JP2016213151A - Separator, cell stack and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technology that prevents generation of flooding in a solid polymer fuel cell.SOLUTION: An anode separator 50 comprises an inner separator 51 that is adhered to an anode side of MEA, and an outer separator 55 that is mounted outside of the inner separator. The inner separator 51 forms a first flow channel including a plurality of first branch flow channels 522 between the inner separator and the MEA in a protrusive space that is made by sheet metal press work. The outer separator 55 forms a plurality of second branch flow channels 564 by covering a groove that is formed between the plurality of first branch flow channels 522 and secures a gas flow-in/flow-out path to the second branch flow channel 564 with a second introduction reservoir part 562 and a second discharge reservoir part 563 that are formed from a protrusive space which is made by sheet metal press work. A vent hole is formed on a bottom of the second branch flow channel 564. Hydrogen gases are made flow into the first branch flow channel 522 and the second branch flow channel 564 in such a manner that circulation directions become opposite to each other.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a separator for a polymer electrolyte fuel cell.

A polymer electrolyte fuel cell (PEFC) is known as one of the fuel cells (see, for example, Patent Document 1).
As one of the problems of polymer electrolyte fuel cells, a phenomenon called “flooding” that degrades battery performance is known. That is, as shown in FIG. 18, in the separator 90 (hydrogen separator, current collector plate constituting the gas diffusion part on the fuel electrode side, bipolar plate) in the single cell constituting the cell stack of the polymer electrolyte fuel cell, A hydrogen flow path 93 is provided in a meandering manner from one edge of the hydrogen inlet 92 toward the opposite edge of the hydrogen outlet 94 for discharging unreacted hydrogen. In the vicinity of the inlet AH corresponding to the upstream side of the hydrogen flow path 93, the hydrogen concentration is high and the generated current is large and the temperature is high. It becomes. For this reason, water generated by the reaction (ionization reaction at the anode surface) near the inlet AH flows into the downstream side as water vapor, but condensation can occur in the vicinity of the outlet AL. The state in which this has progressed is flooding, and the flow path is narrowed by condensed water, and in some cases, the flow path is closed. When flooding occurs, the electrode assembly (solid polymer membrane (electrolyte) and electrode assembly: MEA: Membrane Electrode Assembly) in the cell constituting the cell stack deteriorates due to the oxidative corrosion reaction of the conductive material caused by the accumulated water. As time goes on, power generation is no longer possible.

  As a countermeasure against flooding, for example, a technique is known in which the voltage of each cell is measured and the supply port and the discharge port of hydrogen are switched to reduce the bias in power generation distribution when the voltage drops below a certain voltage. (For example, see Patent Document 2).

JP 2003-317753 A JP 2006-210118 A

  In the technologies disclosed in Patent Documents 1 and 2, it is possible to reduce the state of uneven power generation distribution as much as possible and to suppress the deterioration of MEA (Membrane Electrode Assembly), thereby extending the service life. Unevenness could not be prevented.

  Accordingly, an object of the present invention is to realize a new technique for preventing the occurrence of flooding in a polymer electrolyte fuel cell.

A first invention for solving the above problems is a separator of a polymer electrolyte fuel cell in which a gas flow path for allowing a gas for power generation to flow is formed, the outer separator, the outer separator, and the electrolyte membrane And an inner separator that forms a partition wall between the first gas flow path and the second gas flow path,
The second gas flow path is formed between the outer surfaces of the outer separator and the inner separator, the first gas flow path is formed on the inner surface of the inner separator, and the flow direction of the first gas flow path It is the separator comprised so that the flow direction of the said 2nd gas flow path may run in opposition.

  According to a second aspect of the present invention, the first gas flow path is branched from a first introduction reservoir that temporarily accumulates the gas into the plurality of first branch channels, and the first introduction reservoir. A plurality of first branch passages; and a first discharge reservoir for temporarily storing and discharging the gas flowing through the plurality of first branch passages. , A second introduction reservoir for temporarily storing the gas into the plurality of second branch channels, the plurality of second branch channels branched from the second introduction reservoir, and the plurality of A second discharge reservoir that temporarily stores and discharges the gas flowing through the second branch flow path, and the first branch flow path and the second branch flow path communicate with each other. 1 is a separator according to a first aspect of the present invention, the directions of which are alternately arranged so that the directions thereof are parallel to each other.

  According to a third aspect of the present invention, a cross section of a portion where the inner separator forms a parallel run of the first branch flow path and the second branch flow path is configured in a serpentine shape, and In the separator according to the second aspect of the present invention, an opening leading to the electrolyte membrane is provided in a portion of the second branch channel formed between the separator and the separator.

  According to any one of the first to third inventions, the first gas flow path and the second gas flow path run in opposite directions in the direction of flow of the power generation gas. The high temperature part which concerns on the other gas flow path exists in the vicinity of a part. Therefore, it is difficult to generate a low-temperature portion in which water vapor is condensed, and a structure that can prevent flooding is obtained.

  A fourth invention is the separator according to the second or third invention, wherein the inner separator and the outer separator are manufactured by pressing a metal plate.

  According to the fourth invention, manufacturing is relatively easy and manufacturing cost can be reduced.

  In the separator of any one of the second to fourth inventions, as a fifth invention, the first introduction reservoir and the second discharge reservoir are provided on one edge side of the separator, The first discharge reservoir and the second introduction reservoir can constitute a separator provided on the other edge side of the separator.

  A sixth invention is a cell stack in which one separator is constituted by sandwiching the electrolyte membrane between two separators of the fifth invention.

  According to the sixth invention, the manufacturing cost of the cell stack can be reduced by making both the anode side and cathode side separators the same.

  A seventh invention is a first reaction measuring unit (for example, the first reaction measuring unit shown in FIG. 17) that measures the degree of fuel reaction in the cell stack of the sixth invention and the first region of the cell stack on the one edge side. 1 reaction sensor 71), a second reaction measurement unit (for example, the second reaction sensor 72 in FIG. 17) that measures the degree of fuel reaction in the second region of the cell stack on the other edge side, A first flow rate adjusting unit (for example, the first electric pump 146 in FIG. 17) that adjusts the flow rate to the first introduction reservoir, and a second flow rate adjusting unit (for example, the flow rate to the second introduction reservoir) (for example, , The second electric pump 147 in FIG. 17, and a control unit (for example, in FIG. 17) that controls the first and second flow rate adjustment units based on the measurement results of the first and second reaction measurement units. CPU74), a fuel cell system comprising .

  According to the seventh aspect of the invention, the cell stack of the sixth aspect of the invention is used in which the flow rate is further adjusted for each gas flow path, and the power generation amount, that is, the heat generation amount, can be adjusted for each of the first region and the second region. A fuel cell system can be realized. Even if there is a difference in the degree of reaction between the first region and the second region for some reason, this can be corrected to prevent the occurrence of low-temperature spots that cause condensation.

The structural example of a polymer electrolyte fuel cell shows (1) front view, (2) side view. The perspective appearance figure seen from the front slanting bottom which shows the example of composition of an anode separator. The exploded view of the structural example of an anode separator. It is a figure which shows the structural example of an inner separator, Comprising: (1) Top view, (2) Front view, (3) Bottom view, (4) Side view. AA sectional drawing of FIG. BB sectional drawing of FIG. CC sectional drawing of FIG. DD sectional drawing of FIG. It is a figure which shows the structural example of an outer separator, Comprising: (1) Top view, (2) Front view, (3) Bottom view. FF sectional drawing of FIG. EE sectional drawing of FIG. The figure which shows the system configuration | structure which concerns on the fuel system and control system of the fuel cell system in 1st Embodiment. The front view for demonstrating the 1st flow direction of the hydrogen gas in an anode separator. Sectional drawing for demonstrating the 1st flow direction of the hydrogen gas in the GG cross section of FIG. Front view for explaining the second flow direction of hydrogen gas in the anode separator Sectional drawing for demonstrating the 2nd flow direction of the hydrogen gas in the HH cross section of FIG. The figure which shows the system configuration | structure which concerns on the fuel system and control system of the fuel cell system in 2nd Embodiment. The figure which shows the structural example of the conventional anode separator.

[First Embodiment]
FIG. 1 is a (1) front view and (2) side view showing a configuration example of a polymer electrolyte fuel cell according to a first embodiment.
The cell stack 2 of the polymer electrolyte fuel cell is a type of fuel cell that uses a polymer ion exchange membrane as an electrolyte and uses hydrogen gas and oxygen gas (or the atmosphere) as power generation fuel. The cell stack 2 is formed by laminating a plurality of single cells 5, sandwiching both ends between a minus electrode 6 and a plus electrode 7, and further sandwiching both ends between an insulating plate 8 and end plates 9 a and 9 b and integrally connecting them. ing.

At one edge portion of the negative electrode side end plate 9a, the first hydrogen inflow port 11, the second hydrogen outflow port 14, the second oxygen outflow port 18, , A first oxygen inlet port 15 is provided.
At the opposite edge of the positive electrode side end plate 9b, the first hydrogen outflow port 12, the second hydrogen inflow port 13, and the second oxygen inflow port (in order from the lower right to the left toward the front) 17 and a first oxygen outlet port 16 are provided.

  In the cell stack 2, there are a system extending from the first hydrogen inflow port 11 to each of the single cells 5 to the first hydrogen outflow port 12, and a second hydrogen from the second hydrogen inflow port 13 to each of the single cells 5. Two systems of hydrogen gas flow paths with the system leading to the outflow port 14 are provided. Similarly, the system from the first oxygen inflow port 15 to the first oxygen outflow port 16 around each single cell 5 and the second oxygen inflow port 17 to the second oxygen outflow port 18 from each single cell 5 are reached. Two channels of oxygen gas (or air) with the system are provided.

  The single cell 5 is a unit integrated and laminated so that the MEA 30 is sandwiched between an anode separator 50 (hydrogen separator) and a cathode separator 60 (oxygen separator), similarly to the known PEFC. The number of single cells 5 included in one cell stack 2 can be set as appropriate.

  In the present embodiment, since the anode separator 50 and the cathode separator 60 have the same structure, only the anode separator 50 will be described below.

[Description of separator]
FIG. 2 is a perspective external view of a configuration example of the anode separator 50 according to the present embodiment as viewed from the front obliquely below. FIG. 3 is an exploded view of the anode separator 50.
The anode separator 50 of this embodiment includes an inner separator 51 that contacts the MEA 30, an outer separator 55 that is assembled to the front side of the inner separator 51, and a peripheral edge on the front side of the inner separator 51 so as to surround the outer separator 55. And a gasket 57 assembled to the portion.
If the MEA 30 side is called the inner surface, the anode separator 50 is assembled by mounting the outer separator 55 on the outer surface side of the inner separator 51 and mounting the gasket 57 so as to surround the outer separator 55 on the outer surface side of the inner separator 51. It is done.

4A and 4B are diagrams showing a configuration example of the inner separator 51, which are (1) a top view, (2) a front view, (3) a bottom view, and (4) a side view.
The inner separator 51 is a component that constitutes a partition wall between the first gas channel and the second gas channel through which hydrogen gas is passed, and constitutes a first layer of a channel that supplies hydrogen to the MEA 30. For example, the inner separator 51 is formed by pressing a conductive thin metal plate.

  As shown in FIGS. 2 to 4, the inner separator 51 has a first hydrogen inlet hole 511 connected to the first hydrogen inlet port 11 at the upper edge portion (upper edge portion in FIG. 4) toward the front. A second hydrogen outlet hole 514 connected to the second hydrogen outlet port 14, a second oxygen outlet hole 518 connected to the second oxygen outlet port 18, a first oxygen inlet hole 515 connected from the first oxygen inlet port 15, Is provided.

  A first hydrogen outflow hole 512 connected to the first hydrogen outflow port 12 and a second hydrogen inflow connected from the second hydrogen inflow port 13 are formed in the right side edge portion (lower side edge portion in FIG. A hole 513, a second oxygen inflow hole 517 connected to the second oxygen inflow port 17, and a first oxygen outflow hole 516 connected to the first oxygen outflow port 16 are provided.

  And the 1st flow path 52 is shape | molded so that it may protrude from the back surface side (MEA30 side; inner surface side) of the inner separator 51 to the front side (outer surface side), and the space opened on the back surface side is formed. By bringing the MEA 30 into close contact with the back surface side (inner surface side) of the inner separator 51, a space through which gas flows is formed.

  Specifically, the first flow path 52 includes a first introduction reservoir 521 that diffuses and distributes the gas flowing in from the first hydrogen inflow hole 511 to the left and right, and a plurality of second branches branched from the first introduction reservoir 521. A first branch channel 522 and a first discharge reservoir 523 that joins the gas that has passed through the plurality of first branch channels 522 and guides the gas to the first hydrogen outlet hole 512. In addition, the installation number of the 1st branch flow path 522 can be set suitably.

5 is a cross-sectional view taken along the line AA in FIG. 6 is a cross-sectional view taken along the line BB in FIG. 7 is a cross-sectional view taken along the line CC of FIG. 8 is a cross-sectional view taken along the line DD of FIG.
The first branch channel 522 is a groove that is long in the vertical direction of the inner separator 51 and opens toward the MEA 30 when viewed from the back side (MEA side) of the inner separator 51 by the molding method. That is, the gas flowing into the first branch channel 522 is supplied to the MEA 30 from the opening of the groove.

  When viewed in a C-C cross section (see FIG. 7), the cross section in the left-right direction of the inner separator 51 has a meandering shape, and the interval between the adjacent first branch channels 522 is long in the vertical direction of the inner separator 51 and A groove that opens to the front side is formed and functions as a partition wall between adjacent first branch channels 522.

  When the outer separator 55 is mounted on the front surface (outer surface) of the inner separator 51, a partition wall is formed on the front surface side of the groove between the adjacent first branch flow paths 522. A space through which hydrogen supplied from the second hydrogen inflow hole 513 passes is formed, and a groove between adjacent first branch channels 522 functions as a second branch channel 564. Specifically, a vent hole 565 is provided at the bottom (MEA side) of the second branch channel 564, and the gas flowing into the second branch channel 564 is supplied to the MEA 30 through the vent hole 565. The

  FIGS. 9A and 9B are diagrams illustrating a configuration example of the outer separator 55, which are (1) a top view, (2) a front view, and (3) a bottom view. 10 is a cross-sectional view taken along the line F-F in FIG. 9. 11 is a cross-sectional view taken along line EE in FIG. In FIG. 9, in order to make it easy to understand the relative positional relationship when the outer separator 55 is assembled to the inner separator 51, the groove portion serving as the second branch channel 564 of the inner separator 51 is indicated by a thin broken line in the front view. .

  The outer separator 55 is formed by pressing a conductive metal thin plate, and constitutes a second layer of a flow path for supplying hydrogen to the MEA 30. The outer separator 55 has a second flow path 56 and a fitting piece 551.

The second flow path 56 includes an upper lid portion 561, a second introduction reservoir portion 562, and a second discharge reservoir portion 563.
The upper lid portion 561 is a plate-like portion that adheres to and covers the front side (outer surface side) of the first flow path 52 (see FIG. 4) of the inner separator 51. More specifically, the dimensions of the four sides of the upper lid portion 561 are set so as to just cover the first flow path 52, and the upper lid section 561 covers the front side of the first flow path 52 so that the adjacent first A ceiling of a groove formed between the branch flow paths 522 (a groove having a vent hole 565 at the bottom; see FIG. 4) is formed to function as the second branch flow path 564.

  And the part which covers the upper end part of the 2nd branch flow path 564 and the part which covers the lower end part of the 2nd branch flow path 564 are shape | molded so that each may protrude over the front side among the upper cover parts 561, and the 1st 2 An inlet reservoir 562 and a second outlet reservoir 563 are formed.

The second introduction reservoir 562 opens at the lower end facing the upper side of the second hydrogen inflow hole 513 of the inner separator 51 and expands to the left and right, diffusing the hydrogen flowing from the second hydrogen inflow port 13 (see FIG. 1). Distribute and guide to the second branch channel 564.
The second discharge reservoir 563 has an upper end that opens toward the front side of the second hydrogen outlet hole 514 of the inner separator 51, and combines the gas that has passed through the second branch channel 564 to form a second hydrogen outlet hole. Exhaust to the front side of 514.

  The fitting piece 551 is a connection structure for appropriately holding both the positional relationship and the close contact when the outer separator 55 is put on the front side of the inner separator 51. In the present embodiment, the second flow path 56 extends from the outer periphery of the four sides.

Next, the gasket 57 will be described.
As shown in FIG. 3, the gasket 57 includes a first hydrogen inflow pipe portion 571 connected to the first hydrogen inflow port 11 and a second hydrogen at the edge portion of the upper end portion (upper right side in FIG. 3). It has a second hydrogen outflow pipe part 574 connected to the outflow port 14, a second oxygen outflow pipe part 578 connected to the second oxygen outflow port 18, and a first oxygen inflow pipe part 575 connected from the first oxygen inflow port 15. In addition, the first hydrogen outlet pipe portion 572 connected to the first hydrogen outlet port 12 and the second hydrogen inlet port 13 connected to the second hydrogen inlet port 13 are connected to the edge of the lower end portion (the diagonally lower left side in FIG. 3). It has a hydrogen inflow pipe part 573, a second oxygen inflow pipe part 577 connected from the second oxygen inflow port 17, and a first oxygen outflow pipe part 576 connected to the first oxygen outflow port 16.
An accommodation space 580 for accommodating the outer separator 55 fitted to the inner separator 51 is provided at the center of the gasket 57.

A first introduction reservoir in which a first introduction reservoir 521 (see FIG. 4) of the inner separator 51 is fitted to a wall portion separating the accommodation space 580 and the first hydrogen inflow pipe portion 571 above the accommodation space 580. A part fitting groove 581 is provided. Further, a second discharge reservoir fitting groove 584 in which a second discharge reservoir 563 (see FIG. 9) of the outer separator 55 is fitted to a wall portion separating the accommodating space 580 and the second hydrogen outflow pipe portion 574. Is provided.
Similarly, a first discharge reservoir 523 (see FIG. 4) of the inner separator 51 is fitted to a wall that separates the storage space 580 and the first hydrogen outflow pipe portion 572 below the storage space 580. A first discharge reservoir fitting groove 582 is provided. Further, the second introduction reservoir fitting groove 583 in which the second introduction reservoir 562 (see FIG. 9) of the outer separator 55 is fitted to the wall that separates the storage space 580 and the second hydrogen inflow pipe 573. Is provided.
A plurality of ventilation openings 585 are provided on the left and right wall portions of the accommodation space 580.

[Description of system configuration]
FIG. 12 is a diagram showing a system configuration related to the fuel system and the control system of the fuel cell system 100 of the present embodiment. In addition, since a well-known structure is applicable about other system components, such as an oxygen system, a cooling system, and a humidification system, illustration and description here are abbreviate | omitted.

  The fuel cell system 100 adjusts the hydrogen gas provided from the hydrogen supply source 140 to a predetermined atmospheric pressure by the regulator 142 and supplies the hydrogen gas to the first hydrogen supply pipe 110 and the second hydrogen supply pipe 120 in parallel. The first hydrogen supply pipe 110 is connected to the first hydrogen inlet port 11 of the cell stack 2, and the second hydrogen supply pipe 120 is connected to the second hydrogen inlet port 13. Thereby, the flow direction of the hydrogen gas in the first flow path 52 and the flow direction of the hydrogen gas in the second flow path 56 are opposite to each other, that is, have an opposing relationship.

  A first hydrogen recovery pipe 112 is connected to the first hydrogen outlet port 12 of the cell stack 2, and a second hydrogen recovery pipe 122 is connected to the second hydrogen outlet port 14. Both recovery pipes are led to the gas-liquid separator 144.

The gas-liquid separator 144 is realized by a known gas-liquid separator, an aggregating device, or the like.
An electric pump 146 is connected to the gas-liquid separator 144, and the electric pump 146 sucks unreacted hydrogen gas from which the liquid has been separated from the gas-liquid separator 144, and the first return pipe 117 and the second return pipe 127. To the first hydrogen supply pipe 110 and the second hydrogen supply pipe 120, respectively.

[Description of gas flow in separator]
The anode separator 50 having the structure as described above and the cathode separator 60 constitute one single cell 5 with the MEA 30 sandwiched therebetween, and further, the fuel cell system 100 having the above-described piping configuration is configured, whereby the anode separator 50 In the two gas flow paths that the cathode separator 60 and the cathode separator 60 respectively have, the gas flow directions are opposed to each other.

  FIG. 13 is a front view for explaining the first flow direction of hydrogen gas in the anode separator 50. Note that the outer separator 55 is not shown for easy understanding. FIG. 14 is a cross-sectional view for explaining the first flow direction of hydrogen gas in the GG cross section of FIG. 13.

  As shown in FIG. 13, in the first flow path 52 formed by the inner separator 51, the hydrogen gas that has passed through the first hydrogen inflow pipe portion 571 of the gasket 57 is led to the first introduction reservoir portion 521, where a plurality of hydrogen gases are introduced. The first branch channel 522 is distributed. Then, as shown in FIG. 14, the hydrogen gas flowing into the first branch channel 522 is supplied to the MEA 30 from the opening of the first branch channel 522 and used for the reaction. The hydrogen gas remaining without being reacted flows through the first branch channel 522 below the anode separator 50, is collected by the first discharge reservoir 523, and is discharged to the first hydrogen outlet pipe 572 of the gasket 57.

  The cathode separator 60 is in close contact with the back side of the MEA 30 in an inverted orientation. Since the cathode separator 60 has the same configuration as the anode separator 50, oxygen gas flows through the first flow path 52 of the cathode separator 60. The flow configuration is such that the hydrogen gas in the first flow path 52 of the cathode separator 60 and the MEA 30 are reversed and turned upside down.

  Here, paying attention to the hydrogen concentration in the first flow path 52 of the cathode separator 60, the concentration is higher in the upstream portion, and the concentration is lowered toward the downstream. The higher the concentration of hydrogen gas, the greater the amount of power generated and the higher the amount of heat generated. Therefore, in the first flow path 52 of the cathode separator 60, the heat generation amount is higher at the upper part of the anode separator 50 and the heat generation amount is lower at the lower part, and the lower part is more likely to condense than the upper part of the anode separator 50.

  FIG. 15 is a front view for explaining a second flow direction of hydrogen gas in the anode separator 50. Note that the outer separator 55 is not shown for easy understanding. FIG. 16 is a cross-sectional view for explaining a second flow direction of hydrogen gas in the HH cross section of FIG. 15.

  As shown in FIG. 15, in the second flow path 56 formed by the inner separator 51 and the outer separator 55, the hydrogen gas that has passed through the second hydrogen inflow pipe portion 573 of the gasket 57 is guided to the second introduction reservoir portion 562. There it is distributed to a plurality of second branch channels 564. Then, as shown in FIG. 16, the hydrogen gas that has flowed into the second branch channel 564 is supplied from the vent hole 565 to the MEA 30 and used for the reaction. The hydrogen gas remaining without being reacted flows upward through the second branch channel 564, is collected by the second discharge reservoir 563, and is discharged to the second hydrogen outlet pipe 574 of the gasket 57.

  The cathode separator 60 is in close contact with the back side of the MEA 30 in an inverted orientation. Since the cathode separator 60 has the same configuration as the anode separator 50, oxygen gas flows through the second flow path 56 of the cathode separator 60. The flow form is such that the hydrogen gas in the second flow path 56 of the cathode separator 60 and the MEA 30 are sandwiched and turned upside down.

  Here, paying attention to the hydrogen concentration in the second flow path 56 of the outer separator 55, the concentration is higher in the upstream portion and the concentration is lowered toward the downstream. The higher the concentration of hydrogen gas, the greater the amount of power generated and the higher the amount of heat generated. Therefore, in the second flow path 56, the lower the anode separator 50, the higher the heat generation amount, and the upper the lower the heat generation amount, and the upper portion is more likely to condense than the lower portion.

  Further, here, when comparing the distribution trend of the heat generation amount in the first flow path 52 (broken line in the graph in FIG. 16) with the distribution trend of the heat generation amount in the second flow path 56 (solid line in the graph in FIG. 16). The distribution trend is just reversed. Therefore, since a range of low heat generation for each other can be covered with a range of high heat generation, the overall distribution of the heat generation is more uniform than in the anode separator 50, and condensation is less likely to occur.

  As described at the beginning, the cathode separator 60 has the same structure as the anode separator 50, and the flow direction of the oxygen gas in the two flow paths is also opposite. Therefore, the calorific value distribution in the cathode separator 60 is the same as that in the anode separator 50, and the calorific value distribution is uniform in the cathode separator 60 as a whole and condensation is less likely to occur.

  Therefore, according to the present embodiment, it is possible to realize a new technique for preventing the occurrence of flooding in the polymer electrolyte fuel cell.

[Second Embodiment]
Next, a second embodiment to which the present invention is applied will be described. In the following, only differences from the first embodiment will be described, and the same components are assigned the same reference numerals and redundant description will be omitted.

FIG. 17 is a diagram illustrating a configuration example of the fuel cell system 100B in the present embodiment, and is a diagram illustrating a system configuration related to a fuel system and a control system.
In the fuel cell system 100B, in addition to the configuration of the first embodiment, the second gas-liquid separator 145 and the second electric pump 147 are independently provided between the second hydrogen recovery pipe 122 and the second return pipe 127. Is provided. The structure regarding the 1st flow path 52 and the 2nd flow path 56 in the cell stack 2 is the same as that of 1st Embodiment.

The cell stack 2 includes a first region for measuring a reaction degree (power generation degree) in each of the upper half first area and the lower half second area (see FIG. 4) of the anode separator 50. A reaction sensor 71 and a second reaction sensor 72 are provided.
As for the 1st reaction sensor 71 and the 2nd reaction sensor 72, for example, the magnetic sensor which detects the magnetic change which arises by the generated electric current, the temperature sensor for knowing the calorific value, etc. are attached to the back of the power generation surface of the anode separator 50. It is realized by.
The output signals from these sensors are converted into digital signals via the input interface device 73 corresponding to the type of sensor and input to the computer 74.

  The computer 74 executes a predetermined program so that a difference in power generation distribution between the first region and the second region does not occur based on the input measurement results by the first reaction sensor 71 and the second reaction sensor 72. The first electric pump 146 and the second electric pump 147 are driven and controlled. This prevents flooding.

Specifically, the difference in power generation distribution between the first region and the second region is determined from the difference between the measured values of the first reaction sensor 71 and the second reaction sensor 72.
If the measured value of the first reaction sensor 71 exceeds the measured value of the second reaction sensor 72 by a given reference value or more, it is determined that the power generation amount in the second region has decreased, and the second A control signal for increasing the driving force of the electric pump 147 is output from the output interface device 75. That is, control is performed to increase the power generation amount by increasing the flow rate to the second flow path 56.
On the other hand, when the measured value of the second reaction sensor 72 exceeds the measured value of the first reaction sensor 71 by a given reference value or more, it is determined that the power generation amount in the first region is reduced, A control signal for increasing the driving force of one electric pump 146 is output from the output interface device 75. That is, the power generation amount is increased by increasing the flow rate to the first flow path 52.

  According to the present embodiment, flooding can be basically suppressed as in the first embodiment. Furthermore, even if there is a difference in pressure loss between the first flow path 52 and the second flow path 56 and a difference in power generation amount, this can be corrected and prevented before flooding occurs.

[Modification]
As mentioned above, although embodiment which applied this invention was described, embodiment of this invention is not limited to these, The addition, omission, and change of a component can be performed suitably.

  For example, the posture of the inner separator 51 and the outer separator 55 in the above embodiment, that is, the relationship between the top, bottom, left, and right can be changed as appropriate.

  Further, the anode separator 50 is provided with a hydrogen inflow position and a discharge position at a position of 180 ° opposite to each other across the center of the separator. However, the position can be set at 90 ° or 270 °. It is. In this case, the first branch flow path 522 and the second branch flow path 564 are not linear but bent in an L shape of the alphabet as in the above embodiment. The same applies to the cathode separator 60.

  Moreover, about 2nd Embodiment, the piping structure of collection | recovery and return of unreacted hydrogen can be changed suitably. For example, unreacted hydrogen in the first hydrogen recovery pipe 112 is returned to the second hydrogen supply pipe 120 via the gas-liquid separator 144 and the electric pump 146, and unreacted hydrogen in the second hydrogen recovery pipe 122 is returned to the second hydrogen supply pipe 120. It is good also as a structure which returns to the 1st hydrogen supply piping 110 via the gas-liquid separator 145 and the 2nd electric pump 147.

DESCRIPTION OF SYMBOLS 2 ... Cell stack 5 ... Single cell 50 ... Anode separator 51 ... Inner separator 511 ... 1st hydrogen inflow hole 512 ... 1st hydrogen outflow hole 513 ... 2nd hydrogen inflow hole 514 ... 2nd hydrogen outflow hole 515 ... 1st oxygen inflow Hole 516: First oxygen outflow hole 517: Second oxygen inflow hole 518: Second oxygen outflow hole 52 ... First flow path 521 ... First introduction reservoir 522 ... First branch flow path 523 ... First discharge reservoir 55 ... outer separator 551 ... fitting piece 56 ... second flow path 561 ... upper lid part 562 ... second introduction reservoir part 563 ... second discharge reservoir part 564 ... second branch flow path 565 ... vent hole 57 ... gasket 571 ... first Hydrogen inflow pipe part 572 ... 1st hydrogen outflow pipe part 573 ... 2nd hydrogen inflow pipe part 574 ... 2nd hydrogen outflow pipe part 575 ... 1st oxygen inflow pipe part 576 ... 1st oxygen outflow pipe part 577 ... 2nd Oxygen inflow pipe portion 578 ... second oxygen outflow pipe portion 580 ... accommodating space 581 ... first introduction reservoir fitting groove 582 ... first discharge reservoir fitting groove 583 ... second introduction reservoir fitting groove 584 ... second Discharge reservoir fitting groove 585 ... Ventilation opening 6 ... Negative electrode 7 ... Positive electrode 8 ... Insulating plate 9a, 9b ... End plate 11 ... First hydrogen inflow port 12 ... First hydrogen outflow port 13 ... Second hydrogen inflow port 14 ... second hydrogen outlet port 15 ... first oxygen inlet port 16 ... first oxygen outlet port 17 ... second oxygen inlet port 18 ... second oxygen outlet port 30 ... MEA
DESCRIPTION OF SYMBOLS 60 ... Cathode separator 71 ... 1st reaction sensor 72 ... 2nd reaction sensor 73 ... Input interface device 74 ... Computer 75 ... Output interface device 100 ... Fuel cell system 110 ... 1st hydrogen supply piping 112 ... 1st hydrogen recovery piping 117 ... First return pipe 120 ... second hydrogen supply pipe 122 ... second hydrogen recovery pipe 127 ... second return pipe 140 ... hydrogen supply source 142 ... regulator 144 ... gas-liquid separator 145 ... second gas-liquid separator 146 ... electric Pump 147 ... second electric pump

Claims (7)

A separator of a polymer electrolyte fuel cell in which a gas flow path for allowing a gas for power generation to flow is formed,
An outer separator,
An inner separator provided between the outer separator and the electrolyte membrane and constituting a partition wall between the first gas channel and the second gas channel;
The second gas flow path is formed between the outer surfaces of the outer separator and the inner separator, the first gas flow path is formed on the inner surface of the inner separator, and the first gas flow path The separator comprised so that a flow direction and the flow direction of the said 2nd gas flow path may run side by side in opposing relation. The first gas channel includes a first introduction reservoir that temporarily accumulates the gas into the plurality of first branch channels, and the plurality of first branches branched from the first introduction reservoir. A flow path and a first discharge reservoir for temporarily storing and discharging the gas flowing through the plurality of first branch flow paths,
The second gas channel includes a second introduction reservoir for temporarily storing the gas into the plurality of second branch channels, and the plurality of second branches branched from the second introduction reservoir. A flow path, and a second discharge reservoir for temporarily storing and discharging the gas flowing through the plurality of second branch flow paths,
The first branch flow path and the second branch flow path are alternately configured such that the flow directions of the first branch flow path and the second branch flow path are parallel to each other.
The separator according to claim 1. The inner separator is formed in a meandering cross section of a portion that forms a parallel run of the first branch channel and the second branch channel, and is formed between the outer separator in the serpentine portion. The second branch channel portion is provided with an opening leading to the electrolyte membrane,
The separator according to claim 2. The inner separator and the outer separator are manufactured by pressing a metal plate,
The separator according to claim 2 or 3. The first introduction reservoir and the second discharge reservoir are provided on one edge side of the separator;
The first discharge reservoir and the second introduction reservoir are provided on the other side of the separator,
The separator as described in any one of Claims 2-4.   A cell stack in which one cell is configured by sandwiching the electrolyte membrane between the two separators according to claim 5. A cell stack according to claim 6;
A first reaction measurement unit for measuring a fuel reaction degree in a first region of the cell stack on the one edge side;
A second reaction measuring unit that measures the degree of fuel reaction in the second region of the cell stack on the other edge side;
A first flow rate adjustment unit for adjusting a flow rate to the first introduction reservoir,
A second flow rate adjusting unit for adjusting the flow rate to the second introduction reservoir,
A control unit for controlling the first and second flow rate adjustment units based on the measurement results of the first and second reaction measurement units;
A fuel cell system comprising:

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