JP2014203800A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that reduction in a variation of a flow rate supplied to each fuel cell is insufficient.SOLUTION: An auxiliary flow passage 51 is a flow passage for supplying a manifold 41 with hydrogen. Hydrogen flown in the auxiliary flow passage 51 flows into the manifold 41 through a connection flow passage 61. The connection flow passage 61 is disposed on the right side of a cell stack 20. Thus, hydrogen flows into the manifold 41 from both sides.

Description

  The present invention relates to a fuel cell.

  A manifold is used to supply gas to each of a plurality of cells constituting the fuel cell. The manifold forms a flow path in the cell stacking direction. Since pressure loss occurs in the flow path, the flow rate supplied to each cell varies depending on the position in the flow direction of the flow path. In order to reduce this variation, a configuration in which a baffle plate is provided in the flow path is known (for example, Patent Document 1).

JP 2009-140888 A

  The problem of the prior art is that the variation in the flow rate supplied to each cell is insufficiently reduced.

  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.

(1) According to one aspect of the present invention, a fuel cell system is provided. In this fuel cell system, in order to either supply gas to each of a plurality of stacked cells or to discharge gas from each of the stacked cells, the fuel cell system moves in the cell stacking direction in the cell stack. A manifold that forms a flow path in the cell stack; an auxiliary flow path that forms a flow path in the stacking direction in the cell stack; and a connection flow path that connects the manifold and the auxiliary flow path; The auxiliary flow path is open on the same side. According to this embodiment, variation in the flow rate supplied to each cell is reduced. In the case of a supply manifold, gas flows into the manifold from the connection channel and the manifold opening. Therefore, the pressure loss of the gas flowing in from the opening of the manifold can be compensated by the pressure of the gas flowing in from the connection channel. As a result, the pressure variation in the flow direction of the manifold is reduced, and consequently the flow rate variation of each cell is reduced. In addition, since the manifold and the auxiliary flow path are open on the same side, the configuration of the supply piping can be simplified, which is advantageous in terms of cost. This effect is the same also in the case of the discharge manifold.

(2) A fuel cell system using a polymer electrolyte fuel cell; for either supply of gas to each of a plurality of stacked cells or discharge of gas from each of the stacked cells And a manifold for forming a flow path in the cell stacking direction; the manifold is open on both sides. According to this embodiment, variation in the flow rate supplied to each cell is reduced. In the case of a supply manifold, gas flows into the manifold from openings on both sides. Therefore, the pressure loss of the gas flowing in from one opening can be compensated by the pressure of the gas flowing in from the other opening. As a result, the pressure variation in the flow direction of the manifold is reduced, and consequently the flow rate variation of each cell is reduced. This effect is the same also in the case of the discharge manifold.

Outline of the cell stack. AA sectional drawing of FIG. 1 (B). AA sectional drawing in Embodiment 2. FIG. AA sectional drawing in Embodiment 3. FIG. AA sectional drawing in Embodiment 4. FIG. 6 is a schematic diagram of an auxiliary channel according to a fifth embodiment. The schematic diagram of a flow path. The schematic diagram of a flow path. The schematic diagram of a flow path. The graph which shows the simulation result of the flow volume of each separator. The graph which shows the simulation result in the case of using a connection flow path on the discharge side.

  Embodiment 1 will be described. FIG. 1 shows a cell stack 20. 1A is a front view and FIG. 1B is a side view. The cell stack 20 is a part of a fuel cell system using a polymer electrolyte fuel cell. The cell stack 20 includes a plurality of cells (not shown), a plurality of separators 30, manifolds 41 to 46, and an auxiliary channel 51 inside.

  Each of the manifolds 41 to 46 and the auxiliary flow channel 51 forms a flow channel in the cell stacking direction, and opens on one side (left side) of the cell stack 20. The manifold 41 is a flow path for distributing and supplying hydrogen to the flow path in the separator 30. The manifolds 41 to 46 are flow paths for any of hydrogen discharge, air supply and discharge, and cooling water supply and discharge.

  The auxiliary channel 51 is a channel for supplying hydrogen to the manifold 41. Hydrogen that has flowed into the auxiliary flow path 51 flows into the manifold 41 via the connection flow path 61. The connection channel 61 is disposed on the right side of the cell stack 20 as shown in FIG. Therefore, hydrogen flows into the manifold 41 from both the left and right sides.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. The separator 30 is bonded to one adjacent separator 30 by an adhesive 110 and is bonded to the other adjacent separator 30 by a sealing material 120.

  According to the first embodiment, since hydrogen is supplied from both sides to the manifold 41, it is possible to avoid the gas pressure in the manifold 41 from decreasing as the distance from the opening portion increases. As a result, variation in the flow rate of hydrogen supplied to each separator 30 is reduced.

  FIG. 3 shows an AA cross-sectional view in the second embodiment. As shown in FIG. 3, a part of the seal functioning as a partition wall between the manifold 41 and the auxiliary flow path 51 is replaced with an adhesive 210. A portion where a part of the seal is replaced with the adhesive 210 is deteriorated in sealing performance and functions as the connection flow path 62.

  According to the second embodiment, a portion for allowing hydrogen to flow from the auxiliary flow path 51 to the manifold 41 can be provided in the middle of the manifold 41, and an arbitrary number of connection flow paths 62 can be provided. As a result, the design that suppresses the variation in the flow rate of each separator 30 is facilitated. In the second embodiment, the connection channel 61 may or may not be provided. Also in the following third and fourth embodiments, the connection channel 61 may or may not be provided.

  FIG. 4 is a cross-sectional view taken along the line AA in the third embodiment. As shown in FIG. 4, the sealing material 320 is displaced from the position of the sealing material 120, and the sealing performance is deteriorated. The part where the sealing performance is reduced functions as the connection flow path 63. According to the third embodiment, the same effect as that of the second embodiment can be obtained.

  FIG. 5 is a cross-sectional view taken along the line AA in the fourth embodiment. As shown in FIG. 5, the sealing material 421 forms a gap so that the sealing is insufficient. This gap functions as a connection flow path 64a. The sealing material 422 is located downstream of the sealing material 421. The sealing material 422 forms a larger gap than the sealing material 421. This gap functions as a connection flow path 64b. Thus, if the flow path area of the connection flow path can be adjusted according to the position, the design for suppressing the variation in the flow rate of each separator 30 is facilitated.

  FIG. 6 shows an auxiliary channel 551 of the fifth embodiment. The auxiliary channel 551 is a hollow tube inserted into the manifold 41. The opening of the auxiliary channel 551 is aligned with the opening of the manifold 41 in the stacking direction. On the other hand, the auxiliary flow path 551 is slightly shorter than the manifold 41. As a result, hydrogen flows into the manifold 41 from the auxiliary flow path 551 near the downstream end of the manifold 41. That is, the opening on the downstream side of the auxiliary flow path 551 functions as the connection flow path 65. According to the fifth embodiment, the same effect as the first embodiment can be obtained.

  The auxiliary flow path and the connection flow path in the above-described embodiment are related to the manifold 41 for supplying hydrogen. The auxiliary flow path and the connection flow path are not limited to the manifold 41, and may be related to at least one of the manifolds 41 to 45.

  FIG. 7 is a schematic diagram of a hydrogen flow path. The flow path shown in FIG. 7 corresponds to the case where the auxiliary flow path 51 and the connection flow path 61 related to the manifold 42 are provided, and the auxiliary flow path 52 and the connection flow path 61 related to the manifold 42 are provided. The manifold 42 is for discharging hydrogen.

  FIG. 8 is a schematic diagram of a hydrogen flow path. The flow path shown in FIG. 8 corresponds to the case where the auxiliary flow path 51 and the connection flow path 62 associated with the manifold 41 are provided, and the auxiliary flow path 52 and the connection flow path 62 associated with the manifold 42 are provided.

  FIG. 9 is a schematic diagram of a hydrogen flow path. The flow path shown in FIG. 9 corresponds to a case where hydrogen flows in from both sides of the manifold 41 and hydrogen flows out from both sides of the manifold 42, unlike the embodiment described above.

  In any of the cases shown in FIGS. 7, 8, and 9, an effect of suppressing variation in the flow rate of each separator 30 can be obtained by providing a connection channel in at least one of the manifold 41 and the manifold 42. .

  FIG. 10 shows a simulation result of the flow rate of each separator 30. 10A, 10B, and 10C, the vertical axis indicates the flow rate, and the horizontal axis indicates the position of the separator 30. FIG. 10A shows “first-in / out”, FIG. 10B shows “first-in / out”, FIG. 10C shows the sum of “first-in / out” and “first-in / out”, and “ The case of “First-in, first-out” is shown.

  Unlike the above-described embodiments, the front-in and front-out corresponds to the case where the openings of the manifold 41 and the manifold 42 are on the same side without using the auxiliary flow path and the connection flow path. Unlike the above-described embodiments, the front-in / after-out corresponds to the case where the openings of the manifold 41 and the manifold 42 are on different sides without using the auxiliary flow path and the connection flow path. The total of first-in, first-out and first-in, second-out is equivalent to “first-in, two-out”. Pre-input / exit corresponds to a modification of the above-described embodiment, and corresponds to the case where the auxiliary flow path and the connection flow path are employed on the discharge side.

  “Only first-in / first-out” shown in FIG. 10C corresponds to first-in / first-out, provided that the total amount of flow is the same as in the case of both front-in / out-out. As shown in FIG. 10C, the minimum flow rate (MIN (C)) in the case of the first-in / out-out case is larger than the minimum flow rate (MIN (D)) in the case of only the first-in / out flow. This means that the variation in the flow rate of each separator 30 is reduced by the front-in / out-out.

  FIG. 11 shows a simulation result when the connection channel 62 is used on the discharge side. This simulation was performed in order to determine the number and positions of the connecting flow paths with the aim of suppressing the flow rate variation as much as possible. As a result, the four connection flow paths 62 were arranged as shown in FIG.

  In each of the six graphs shown in FIG. 11, the vertical axis indicates the flow rate, and the horizontal axis indicates the position of the separator 30. A shows a case where hydrogen is discharged only from the manifold 42, and B shows a case where hydrogen is discharged only from the auxiliary flow path 52 via only the connection flow path 62B. C to E are the same as B. The curve indicating the sum is a value obtained by summing A to E. When A to E are totaled, the variation in flow rate is suppressed as compared with the case of only the first-in / out-out.

  The present invention is not limited to the embodiments, examples, and modifications of the present specification, and can be implemented with various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in the embodiments 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 described above, replacement or combination can be performed as appropriate. If the technical feature is not described as essential in this specification, it can be deleted as appropriate.

20 ... Cell stack 30 ... Separator 41 ... Manifold 42 ... Manifold 43 ... Manifold 44 ... Manifold 45 ... Manifold 46 ... Manifold 51 ... Auxiliary channel 52 ... Auxiliary channel 61 ... Connection channel 62 ... Connection channel 62B ... Connection channel 62C ... Connection channel 62D ... Connection channel 62E ... Connection channel 63 ... Connection channel 64a ... Connection channel 64b ... Connection channel 65 ... Connection channel 110 ... Adhesive 120 ... Sealing material 210 ... Adhesive 320 ... Seal Material 421 ... Sealing material 422 ... Sealing material 551 ... Auxiliary flow path

Claims (2)

A flow path in the cell stacking direction is formed in the cell stack for either supply of gas to each of the plurality of stacked cells or discharge of gas from each of the plurality of stacked cells. Manifold,
An auxiliary flow path that forms a flow path in the stacking direction in the cell stack;
A connection flow path for connecting the manifold and the auxiliary flow path,
The manifold and the auxiliary flow path are open on the same side. A fuel cell system using a polymer electrolyte fuel cell,
A manifold that forms a flow path in the stacking direction of the cells for either gas supply to each of the stacked cells or gas discharge from each of the stacked cells,
The manifold is open on both sides of the fuel cell system.

Images