JP2011249010A - Fuel cell stack device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack device that contributes to reduction in power generation unevenness in a stacking direction of cells by suppressing an excessive temperature drop at an end cell positioned at an end in the stacking direction of the stack.SOLUTION: A refrigerant passage structure 7 of a stack 1 includes intermediate refrigerant passages 70 of intermediate cells 2C present in the middle in the stack direction, and end refrigerant passages 72, 73 of end cells 2E, 2F present at ends in the stack direction. A refrigerant supplied from a refrigerant supply passage 5 to an entrance is flown to the intermediate refrigerant passages 70 of the intermediate cells 2C to cool the intermediate cells 2C, and the refrigerant which flows in the intermediate refrigerant passages 70 and receives heat from the intermediate cells 2C to be made warm is flown to the end refrigerant passages 72, 73 to cool the end cells 2E, 2F.

Description

  The present invention relates to a fuel cell stack device in which a plurality of cells are stacked.

  A fuel cell stack device is formed by stacking a plurality of cells having a membrane electrode assembly and separators sandwiching the membrane electrode assembly on both sides in the thickness direction, and having a refrigerant passage structure through which a refrigerant flows. A refrigerant supply passage communicating with the inlet of the refrigerant passage structure of the stack and a refrigerant discharge passage communicating with the outlet of the refrigerant passage structure of the stack (Patent Document 1). In such a stack apparatus, the end cell located at the end in the stacking direction tends to have high heat dissipation. For this reason, there is a risk of excessive temperature drop in the end cell. On the other hand, in the intermediate cell on the intermediate side in the stacking direction of the stack, there is a tendency for heat dissipation to be low and heat dissipation to be high. For this reason, in the fuel cell stack device, the temperature unevenness of the cells in the stacking direction is large, and power generation unevenness may occur in the stacking direction. In particular, in the case of a polymer electrolyte fuel cell, an excessive temperature drop in the end cell is a factor causing flooding, which is not preferable. Flooding refers to constraining the flow of reaction gas by narrowing the gas flow path area of a membrane electrode assembly or the like with liquid-phase water.

Japanese Patent Laid-Open No. 8-111231

  The present invention has been made in view of the above circumstances, and a fuel cell stack device that can suppress an excessive temperature drop in an end cell with high heat dissipation in the stack and contribute to reduction of power generation unevenness in the cell stacking direction. The issue is to provide.

  (1) The fuel cell stack device according to the present invention of aspect 1 is formed by laminating a plurality of cells each having a membrane electrode assembly and separators sandwiching both sides of the membrane electrode assembly in the thickness direction. A stack having a refrigerant passage structure for flowing a refrigerant, a refrigerant supply passage communicating with an inlet of the refrigerant passage structure of the stack, and a refrigerant discharge passage communicating with an outlet of the refrigerant passage structure of the stack. The structure has an intermediate refrigerant passage of an intermediate cell that exists in the middle of the stacking direction of the stack and an end refrigerant passage of an end cell that exists at the end of the stacking direction, and is supplied from the refrigerant supply passage To the intermediate refrigerant passage of the intermediate cell to cool the intermediate cell, and the refrigerant that flows through the intermediate refrigerant passage and receives heat from the intermediate cell and flows through the end refrigerant passage of the end cell to exchange heat with the end cell. Yes That.

  According to aspect 1, the refrigerant supplied from the refrigerant supply passage is preferentially caused to flow not in the end refrigerant passage of the end cell but in the intermediate refrigerant passage of the intermediate cell that tends to rise in temperature due to heat confinement, and the intermediate cell is given priority. Let cool. Thereafter, as described above, the refrigerant that has flowed through the intermediate refrigerant passage and received heat from the intermediate cell and warmed is passed through the end refrigerant passage of the end cell to exchange heat with the end cell. Therefore, an excessive drop in temperature in the end cell with high heat dissipation is suppressed. For this reason, the temperature unevenness of the cell in the stacking direction of the stack is reduced.

  (2) In the fuel cell stack device according to the second aspect of the present invention, the refrigerant supplied from the refrigerant supply passage flows into the intermediate refrigerant passage of the intermediate cell to cool the intermediate cell, and flows through the intermediate refrigerant passage to receive heat from the intermediate cell. Thus, it has the same technical characteristics as the aspect 1 in that it has a structure in which the heated refrigerant flows through the end refrigerant passage of the end cell and exchanges heat with the end cell. That is, the fuel cell stack device according to the present invention of aspect 2 is formed by laminating a plurality of cells having a membrane electrode assembly and separators sandwiching the membrane electrode assembly on both sides in the thickness direction, and a refrigerant. A stack having a refrigerant passage structure for flowing the refrigerant, a refrigerant supply passage communicating with an inlet of the refrigerant passage structure of the stack, and a refrigerant discharge passage communicating with an outlet of the refrigerant passage structure of the stack. The intermediate refrigerant passage of the intermediate cell that exists in the middle of the stacking direction, the end refrigerant passage of the end cell that exists at the end of the stacking direction, and the refrigerant that flows through the intermediate refrigerant passage but does not flow through the end refrigerant passage A flow rate control element that adjusts a ratio between the refrigerant flow rate α1 that flows and the refrigerant flow rate α2 that flows through the intermediate refrigerant passage and the end refrigerant passage and reaches the refrigerant discharge passage, and the refrigerant supply passage The refrigerant supplied from the intermediate cell is allowed to flow through the intermediate refrigerant passage of the intermediate cell to cool the intermediate cell, and the refrigerant that has flowed through the intermediate refrigerant passage and received heat from the intermediate cell to flow through the end refrigerant passage of the end cell passes through the end cell. It has a structure for heat exchange.

  According to the aspect 2, the refrigerant supplied from the refrigerant supply passage is preferentially flowed not to the end refrigerant passage of the end cell but to the intermediate refrigerant passage of the intermediate cell that tends to rise in temperature due to heat accumulation, thereby cooling the intermediate cell. . Thereafter, as described above, the refrigerant that has flowed through the intermediate refrigerant passage and received heat from the intermediate cell and warmed is passed through the end refrigerant passage of the end cell to exchange heat with the end cell. Therefore, an excessive drop in temperature in the end cell with high heat dissipation is suppressed. For this reason, the temperature unevenness of the cell in the stacking direction of the stack is reduced.

  According to aspect 2, if the opening degree of the flow rate control element is adjusted in the power generation operation of the stack, the refrigerant flow rate α1 per unit time reaching the refrigerant discharge passage without flowing through the end refrigerant passage though flowing through the intermediate refrigerant passage, The ratio with the refrigerant | coolant flow volume (alpha) 2 per unit time which flows through an intermediate | middle refrigerant path and an end refrigerant path, and reaches | attains a refrigerant | coolant discharge path can be adjusted. In other words, the flow rate per unit time of the refrigerant that flows through the end refrigerant passage and exchanges heat with the end cell can be adjusted, and since this refrigerant is warmed through the intermediate refrigerant passage of the intermediate cell, The amount of heat exchange can be adjusted, and the temperature of the end cell can be adjusted.

  ADVANTAGE OF THE INVENTION According to this invention, the excessive temperature fall in the end cell with more heat dissipation than a middle cell can be suppressed among stacks. Therefore, it is possible to contribute to reduction of power generation unevenness in the cell stacking direction.

1 is a perspective view schematically showing a concept of a main part of a stack device according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view schematically showing a main part concept of the stack device according to the first embodiment. FIG. 3 is a side view of an intermediate separator used in the intermediate cell according to the first embodiment. FIG. 3 is a side view of an end separator used in the end cell according to the first embodiment. FIG. 4 is a side view of the current collector plate according to the first embodiment. FIG. 4 is a side view of the first end plate according to the first embodiment. FIG. 10 is a perspective view schematically showing a main part concept of a stack device according to the second embodiment. FIG. 10 is a perspective view schematically showing a main part concept of a stack device according to a sixth embodiment.

  Fuel cells include fluorocarbon electrolyte membranes such as perfluorosulfonic acid polymers, solid polymer fuel cells using hydrocarbon electrolyte membranes, solids using electrolyte membranes such as polybenzimidazole impregnated with phosphoric acid A polymer fuel cell is exemplified. In short, any method may be used as long as a plurality of cells are stacked in the thickness direction and the cells are cooled with a refrigerant. Examples of the refrigerant include a cooling liquid such as cooling water, a cooling gas, and a cooling mist. The intermediate refrigerant passage only needs to cool the intermediate cell, and can be formed using a separator that constitutes an adjacent cell. The end refrigerant passage only needs to cool the end cell, and may be formed by using an end separator constituting the end cell or a current collecting plate adjacent to the end separator. The flow rate control element includes a refrigerant flow rate α1 that flows through the intermediate refrigerant passage but does not flow through the end refrigerant passage and reaches the refrigerant discharge passage, and a refrigerant flow rate α2 that flows through the intermediate refrigerant passage and the end refrigerant passage and reaches the refrigerant discharge passage. Anything can be used as long as the ratio can be adjusted. A flow control valve, a variable orifice, etc. are illustrated.

  Preferably, the stack includes a first refrigerant inlet for supplying a refrigerant from the refrigerant supply passage to an inlet of the refrigerant passage structure of the stack, and a refrigerant that is warmed by receiving heat from the intermediate cell through the intermediate refrigerant passage of the stack. A first refrigerant outlet that flows into the refrigerant discharge passage without flowing into the end refrigerant passage of the cell, and a refrigerant that has flowed through the intermediate refrigerant passage and received heat from the intermediate cell and warmed to the refrigerant discharge passage through the end refrigerant passage of the end cell. And a second refrigerant outlet for flowing. In this case, an inlet temperature sensor for detecting the refrigerant inlet temperature Tin at the first refrigerant inlet, a first outlet temperature sensor for detecting the first outlet temperature Tout1 of the refrigerant discharged from the first refrigerant outlet of the stack, It is preferable to include a second outlet temperature sensor that detects a second outlet temperature Tout2 of the refrigerant discharged from the second refrigerant outlet. The control device sets the opening of the flow rate control element so that the second outlet temperature Tout2 becomes plus or minus τ ° C. (τ = 0 to 7 ° C. or 0 to 5 ° C.) with respect to the inlet temperature Tin. It is preferable to adjust. τ is preferably 0 to 3 ° C. In this case, it becomes advantageous to make the cell surface temperature distribution of the end cell close to the cell surface temperature distribution of the intermediate cell, and the cell surface temperature distribution of all the cells can be made as similar as possible.

(Embodiment 1)
1 to 6 show the concept of the first embodiment. The fuel cell stack device is a polymer electrolyte fuel cell, and includes a stack 1, a refrigerant supply passage 5, and a refrigerant discharge passage 6. The refrigerant supply passage 5 includes a pump 50 that functions as a refrigerant conveyance source that conveys a refrigerant that cools the stack 1 and adjusts the temperature. Examples of the refrigerant include a cooling liquid such as cooling water, a cooling gas, and a cooling mist. In short, any fluid that can exchange heat may be used. The stack 1 is formed by stacking a large number of cells 2. The single cell 2 includes a membrane electrode assembly 3 and a separator 4 that sandwiches the membrane electrode assembly 3 on both sides in the thickness direction. The membrane electrode assembly 3 is formed of a solid polymer electrolyte membrane 30 having ion conductivity (proton conductivity), and an anode 31 and a cathode 32 sandwiching the electrolyte membrane 30 in the thickness direction thereof. The anode 31 is formed of a catalyst layer that causes fuel to undergo an anode power generation reaction and a porous gas diffusion layer that supplies fuel while diffusing the fuel into the catalyst layer. The cathode 32 is formed of a catalyst layer that causes a cathode gas to generate a power and a porous gas diffusion layer that supplies the cathode layer while diffusing the cathode gas.

  As shown in FIG. 1, the stack 1 includes a stacked body 10 having a power generation function formed by stacking a plurality of cells 2 in the thickness direction (arrow A direction), and one end side of the stacked body 10 in the stacking direction. The current collector plate 11r formed of the provided conductive material, the first end plate 11 provided outside the current collector plate 11r via an electrical insulating plate (not shown), and the other end in the stacking direction of the stacked body 10 A current collecting plate 11t made of a conductive material provided on the side, and a second end plate 12 provided on the outside of the current collecting plate 11t via an electric insulating plate (not shown). As shown in FIG. 1, the first end plate 11 includes a single refrigerant inlet 13 to which the refrigerant flowing from the refrigerant supply passage 5 is supplied, and a first refrigerant outlet 14 and a second refrigerant outlet 15 that communicate with the refrigerant discharge passage 6. And have. The refrigerant inlet 13 is provided on the upper side of the stack 1. This is because the refrigerant flows downward in an intermediate refrigerant passage 70 described later in the stack 1. As shown in FIG. 1, the first refrigerant outlet 14 is provided on the lower side of the stack 1. The second refrigerant outlet 15 is provided on the upper side of the stack 1 so as to be located on the side opposite to the first refrigerant outlet 14 in the height direction.

  As shown in FIG. 1, the stacked body 10 constituting the stack 1 includes a power generation intermediate cell 2C that exists in the middle of the stacking direction (arrow A direction) and a power generation end cell that exists on one end side in the stacking direction. 2E and a power generation end cell 2F existing on the other end side in the stacking direction. The end cell 2E means an end cell arranged on one end side in the stacking direction (arrow A direction) in the stacked body 10 of the stack 1. The end cell 2F means an end cell arranged on the other end side in the stacking direction (arrow A direction) in the stacked body 10 of the stack 1. Here, the end cell 2 </ b> E on one end side can be the single end cell 2 on the one end side in the stacking direction (arrow A direction) in the stacked body 10. The end cell 2 </ b> F on the other end side can be the one end cell 2 on the other end side in the stacking direction (arrow A direction) of the stacked body 10. In the stacked body 10 of the stack 1, the remaining cells 2 other than the end cells 2E and 2F correspond to the intermediate cell 2C. For example, when 40 cells 2 are stacked, the cell 2 on one end side in the stacking direction (arrow A direction) and the cell 2 on the other end side have high heat dissipation, and therefore correspond to the end cells 2E and 2F. . The remaining 38 cells 2 correspond to the intermediate cell 2C.

  As shown in FIG. 2, the stack 1 includes a refrigerant passage structure 7 for adjusting the temperature of the stack 1 by flowing a refrigerant and exchanging heat with the stack 1 during a power generation operation. As shown in FIG. 2, the refrigerant passage structure 7 includes an intermediate refrigerant passage 70 that cools the intermediate cell 2C, an end refrigerant passage 72 that exchanges heat between the end cells 2E, and an end refrigerant passage 73 that exchanges heat between the end cells 2F. The flow rate control valve 78 functions as a flow rate control element for adjusting the flow rate of the refrigerant per unit time flowing through the end refrigerant passages 72 and 73.

  That is, the intermediate refrigerant passage 70 exists in the intermediate cell 2C existing in the middle of the stacking direction (arrow A direction), and cools the intermediate cell 2C. The end refrigerant passage 72 exists in the end cell 2E existing at the end in the stacking direction (arrow A direction), and exchanges heat with the end cell 2E. The end refrigerant passage 73 exists in the end cell 2F existing at the end in the stacking direction (arrow A direction), and exchanges heat with the end cell 2F.

  As shown in FIGS. 1 and 2, the refrigerant discharge passage 6 includes a first discharge passage 61 that connects the first refrigerant outlet 14 of the stack 1 and the inlet port 78 i of the flow control valve 78, and the second refrigerant of the stack 1. It has the 2nd discharge passage 62 which makes the exit 15 and the exit port 78p side of the flow control valve 78 communicate, and the main discharge passage 63 where the 1st discharge passage 61 and the 2nd discharge passage 62 merge. Since the leading end of the main discharge passage 63 is connected to a refrigerant cooling element 65 such as a radiator, the refrigerant flowing through the main discharge passage 63 is cooled by the refrigerant cooling element 65. The refrigerant cooling element 65 may be anything as long as it has a function of cooling the refrigerant. When a hot water storage tank is provided in which heat of the warm refrigerant discharged from the stack 1 is exchanged by a heat exchanger and stored as warm hot water, the refrigerant cooling element 65 heats the refrigerant and hot water to each other. You may form with the heat exchanger made to exchange.

  An inlet port 78 i of the flow control valve 78 communicates with the first refrigerant outlet 14 of the stack 1 via the first discharge passage 61. The 1st refrigerant | coolant outlet 14 means the exit which discharges | emits the refrigerant | coolant which flowed through the intermediate | middle refrigerant path 70 in the intermediate cell 2C, but was not heated through the end refrigerant paths 72 and 73 in the end cells 2E and 2F. The outlet port 78p of the flow control valve 78 communicates with the second refrigerant outlet 15 of the stack 1 through the second discharge passage 62. The second refrigerant outlet 15 means an outlet through which the refrigerant flowing through the intermediate refrigerant passage 70 in the intermediate cell 2C and then the refrigerant flowing through the end refrigerant passages 72 and 73 in the end cells 2E and 2F is discharged.

  FIG. 3 shows a side view of the intermediate separator 4C constituting the intermediate cell 2C. The intermediate separator 4C has a mark 89 for alignment. The intermediate separator 4C is made of a conductive material such as carbon or alloy steel, and includes a first manifold hole 81, a second manifold hole 82, a third manifold hole 83, and a fuel supply hole for supplying fuel to the anode. 84, an air supply hole 86 for supplying air (cathode gas) to the cathode, a fuel discharge hole 85 for discharging fuel from the anode, an air discharge hole 87 for discharging air from the cathode, A surface passage 88 that communicates the first manifold hole 81 and the second manifold hole 82 along the surface direction of the intermediate separator 4C is provided. The surface passage 88 is formed with a guide projection (not shown) for bending the coolant. As shown in FIG. 3, in the intermediate separator 4C, the first manifold hole 81, the second manifold hole 82, the third manifold hole 83, the fuel supply hole 84, the air supply hole 86, and the fuel discharge hole 85 The air discharge hole 87 penetrates in the thickness direction of the intermediate separator 4C. The surface passage 88 of the intermediate separator 4C is formed so that the coolant flows along the surface of the intermediate separator 4C, and does not communicate with the third manifold hole 83, but the first manifold hole 81 and the second manifold hole 82. In this case, as shown in FIG. 3, in the intermediate separator 4C, the refrigerant supplied from the first manifold hole 81 passes through the surface passage 88 in the direction of the arrow B1 (downward) from the intermediate separator 4C (intermediate cell 2C). The intermediate separator 4 </ b> C (intermediate cell 2 </ b> C) is cooled while being heated by receiving heat and discharged from the second manifold hole 82. Accordingly, the intermediate refrigerant passage 70 heat-exchanges with the intermediate cell 2C having the intermediate separator 4C to cool it, and the first manifold hole 81, the surface passage 88, the second manifold formed in the intermediate separator 4C. It is formed using the hole 82.

  FIG. 4 shows a side view of the end separator 4E constituting the end cell 2E. The end separator 4E has a mark 89 for alignment. The end separator 4E is made of a conductive material such as carbon or alloy steel, and supplies fuel for supplying fuel to the first manifold hole 81, the second manifold hole 82, the third manifold hole 83, and the anode. Hole 84, air supply hole 86 for supplying air to the cathode, fuel discharge hole 85 for discharging fuel from the anode, air discharge hole 87 for discharging air from the cathode, and second manifold hole And a surface passage 88 for allowing the second manifold hole 83 and the third manifold hole 83 to communicate with each other along the surface direction of the separator 4E. The surface passage 88 is formed with a guide projection (not shown) for bending the coolant.

  As shown in FIG. 4, in the end separator 4E, a first manifold hole 81, a second manifold hole 82, a third manifold hole 83, a fuel supply hole 84, an air supply hole 86, and a fuel discharge hole 85 are provided. The air discharge hole 87 penetrates in the thickness direction of the end separator 4E. The surface passage 88 of the end separator 4E communicates with the second manifold hole 82 and the third manifold hole 83, although it does not communicate with the first manifold hole 81. In this case, as shown in FIG. 4, in the end separator 4E, the refrigerant supplied from the second manifold hole 82 to the surface passage 88 passes through the surface passage 88 of the end separator 4E in the direction of arrow B2 (upward) and ends. Heat exchange with the end separator 4E is made while coming into contact with the separator 4E, and the heat is discharged from the third manifold hole 83. In this case, since the refrigerant flows upward against the gravity (in the direction of arrow B2), it is advantageous to fill the refrigerant with the surface passage 88 of the end separator 4E. Therefore, the refrigerant receives heat from the intermediate cell 2C (intermediate separator 4C). There is an advantage that the heat exchange time between the warmed refrigerant and the end separator 4E can be secured. Thus, since the end refrigerant passage 72 cools the cell 2E having the end separator 4E, the second manifold hole 82, the surface passage 88, the third manifold hole 83, the current collector formed in the end separator 4E. It is formed using the surface 11rs (see FIG. 2) of the plate 11r.

  FIG. 5 shows a side view of the current collector 11t on the other end side. In the current collector plate 11t, a refrigerant port 13t that overlaps and faces the first manifold hole 81, a refrigerant port 14t that overlaps and communicates with the second manifold hole 82, a refrigerant port 15t that communicates with the third manifold hole 83, and a refrigerant A communication path 88t that communicates the openings 14t and 15t along the surface direction of the current collector plate 11t is formed so as not to penetrate the current collector plate 11t in the thickness direction. In this case, as shown in FIG. 5, in the current collector plate 11t, the refrigerant supplied to the refrigerant port 14t through the second manifold hole 82 passes through the surface passage 88t of the current collector plate 11t in the direction of arrow B3 (upward). By contacting the end separator 4F (adjacent to the current collector plate 11t), heat is exchanged with the end separator 4F (end cell 2F), and the heat is discharged to the third manifold hole 83 through the refrigerant port 15t. . In this case, the refrigerant flows upward (in the direction of arrow B3 shown in FIG. 5) against gravity. In this case, there is an advantage that the heat exchange time between the warm refrigerant received from the intermediate cell 2C (intermediate separator 4C) and the end separator 4F (end cell 2F) can be secured. In this way, the end refrigerant passage 73 exchanges heat with the end cell 2F having the other end separator 4F, and the refrigerant port 14t, the surface passage 88t, the refrigerant port 15t, the end cell formed in the current collector plate 11t. It is formed using the surface 4Fs (see FIG. 2) of the 2F end separator 4F.

  FIG. 6 shows a side view of the first end plate 11 on one end side. As shown in FIG. 6, in the first end plate 11, the coolant inlet 13 facing the first manifold hole 81, the first coolant outlet 14 communicating with the second manifold hole 82, and the third manifold hole 83 are communicated. The communicating second refrigerant outlet 15 is formed so as to penetrate the first end plate 11 in the thickness direction. Further, a fuel supply hole 84, an air supply hole 86, a fuel discharge hole 85, and an air discharge hole 87 are formed so as to penetrate in the thickness direction of the first end plate 11. At the time of assembly, the intermediate separator 4C, the end separators 4E and 4F, and the current collecting plates 11r and 11t are laminated in the thickness direction together with the end plates 11 and 12 in a state where these marks 89 are aligned. Is configured. As shown in FIG. 1, the laminate 10 is sandwiched between the first end plate 11 and the second end plate plate 12 via current collector plates 11 r and 11 t. In this case, the first manifold hole 81 of the intermediate separator 4C, the first manifold hole 81 of the end separator 4E, the refrigerant inlet 13 of the first end plate 11, and the refrigerant outlet 13t of the current collector plate 11t overlap and communicate with each other. . Similarly, the second manifold hole 82 of the intermediate separator 4C, the second manifold hole 82 of the end separator 4E, the first refrigerant outlet 14 of the first end plate 11, and the refrigerant outlet 14t of the current collector plate 11t overlap. Communicate. Similarly, the third manifold hole 83 of the intermediate separator 4C, the third manifold hole 83 of the end separator 4E, the second refrigerant outlet 15 of the first end plate 11, and the refrigerant outlet 15t of the current collector plate 11t overlap. Communicate. The same applies to the fuel supply hole 84. The same applies to the fuel discharge hole 85. The same applies to the air supply hole 86. The same applies to the air discharge hole 87.

  Next, the operation of the flow control valve 78 will be described. If the opening degree of the flow control valve 78 is 0 and the cross-sectional area of the flow path is 0, the flow rate α1 of the refrigerant flowing from the first refrigerant outlet 14 and the first discharge passage 61 to the inlet port 78i of the flow control valve 78 can be eliminated. Theoretically, all the refrigerant that has flowed through the intermediate cooling passage 70 can flow into the end refrigerant passages 72 and 73 of the end cells 2E and 2F, and can flow from the second discharge passage 62 to the main discharge passage 63. Therefore, if the opening of the flow control valve 78 is reduced to reduce the cross-sectional area of the flow path that connects the ports 78i and 78p, the inlet port 78i of the flow control valve 78 from the first refrigerant outlet 14 and the first discharge passage 61. It is possible to reduce the flow rate α1 of the refrigerant flowing through the unit time. Accordingly, the flow rate α2 per unit time of the refrigerant that flows through the end refrigerant passages 72 and 73, the second refrigerant outlet 15 and the second discharge passage 63 and reaches the main discharge passage 63 can be increased. In this case, it is possible to increase the amount of heat exchange with which heat is exchanged between the refrigerant that has been warmed by receiving heat from the intermediate refrigerant passage 70 and the end refrigerant passages 72 and 73 (end separators 4E and 4F, end cells 2E and 2F). In other words, the main discharge of the refrigerant discharge passage 6 flows from the first refrigerant outlet 14 and the first discharge passage 61 through the inlet port 78i and the outlet port 78p of the flow control valve 78 without flowing through the end refrigerant passages 72 and 73. The refrigerant flow rate α1 reaching the passage 63 can be reduced.

  On the contrary, when the opening degree of the flow control valve 78 is increased to increase the cross-sectional area of the flow path, the flow flows from the first discharge passage 61 to the main discharge passage 63 through the inlet port 78i and the outlet port 78p of the flow control valve 78. The flow rate α1 of the refrigerant can be increased. That is, the refrigerant flow rate α1 that flows through the flow rate control valve 78 without reaching the end refrigerant passages 72 and 73 and reaches the refrigerant discharge passage 6 can be increased. As a result, the refrigerant flow rate α2 that flows through the end refrigerant passages 72 and 73 and reaches the main discharge passage 63 can be reduced. In this case, the amount of heat exchange with which the refrigerant flowing through the end refrigerant passages 72 and 73 and the end separators 4E and 4F (end cells 2E and 2F) exchange heat can be reduced. In other words, when the opening degree of the flow rate control valve 78 is adjusted and the flow passage cross-sectional area thereof is adjusted, the refrigerant flow rate that reaches the main discharge passage 63 of the refrigerant discharge passage 6 without flowing through the end refrigerant passages 72 and 73. The ratio between α1 and the refrigerant flow rate α2 that flows through the end refrigerant passages 72 and 73 and reaches the main discharge passage 63 of the refrigerant discharge passage 6 can be adjusted. That is, the flow control valve 78 can adjust α1 / α2. As a result, the amount of heat exchange between the refrigerant in the end refrigerant passages 72 and 73 and the end separators 4E and 4F (end cells 2E and 2F) can be adjusted by flowing through the intermediate cell 2C and the end separators 4E and 4F (end cells 2E). , 2F) can be adjusted.

  According to the present embodiment, as can be understood from FIG. 2, when the pump 50 is operated when the flow control valve 78 is closed (opening degree 0), the refrigerant in the refrigerant supply passage 5 is changed to the first end plate 11. The refrigerant inlet 13 and the first manifold hole 81 of the end separator 4E of the end cell 2E reach the first manifold holes 81 of the plurality of intermediate separators 4C. Further, the refrigerant flows downward (in the direction of the arrow B1) through the surface passages 88 of the plurality of intermediate separators 4C to cool the intermediate separator 4C, and eventually cool all the intermediate cells 2C. Warmed. The refrigerant thus heated reaches the second manifold hole 82 of the end separator 4E on one end side via the second manifold holes 82 of the plurality of intermediate separators 4C, and further flows through the surface passage 88 of the end separator 4E. Heat exchange with the end separator 4E (end cell 2E), and further flows in the order of the third manifold hole 83 of the end separator 4E. Furthermore, the second refrigerant outlet 15 of the first end plate 11, the second discharge passage 62, It flows in the order of the main discharge passage 63. Further, when the refrigerant heated from the intermediate cell 2C reaches the refrigerant port 14t of the current collector plate 11t on the other end side (facing the second manifold hole 82 of the intermediate separator 4C), the surface passage of the current collector plate 11t is further increased. 88t flows upward (in the direction of arrow B3) to exchange heat with the end separator 4F (end cell 2F), and further flows to the refrigerant port 15t of the current collector plate 11t, and then flows to the third manifold hole 83 of the intermediate cell 2C. Furthermore, the second refrigerant outlet 15 of the first end plate 11, the second discharge passage 62, and the main discharge passage 63 flow in this order. In other words, as can be understood from FIG. 3, the refrigerant flowing through the intermediate refrigerant passage 70 in the intermediate cell 2C is the first manifold hole 81 of the intermediate separator 4C → the surface passage 88 of the intermediate separator 4C → the second manifold hole of the intermediate separator 4C. It flows in the order of 82. Therefore, the intermediate refrigerant passage 70 is formed using the first manifold hole 81 of the intermediate separator 4C, the surface passage 88 of the intermediate separator 4C, and the second manifold hole 82 of the intermediate separator 4C.

  As can be understood from FIG. 4, the refrigerant flowing through the end refrigerant passage 72 in the end cell 2E flows from the second manifold hole 82 of the end separator 4E → the surface passage 88 of the end separator 4E → the third manifold hole 83 of the end separator 4E. It flows in the order. Therefore, the end refrigerant passage 72 is formed by the second manifold hole 82 of the end separator 4E, the surface passage 88 of the end separator 4E, the third manifold hole 83 of the end separator 4E, and the current collector plate 11r. In addition, as can be understood from FIG. 5, the refrigerant flowing through the end refrigerant passage 73 in the current collector plate 11t flows in the order of the refrigerant port 14t → the surface passage 88t → the refrigerant port 15t. Therefore, the end refrigerant passage 73 is formed using the refrigerant port 14t, the surface passage 88t, and the refrigerant port 11t of the current collector plate 11t.

  In use, fuel (for example, hydrogen gas) is supplied to the anode 31 of the membrane electrode assembly 3 and air as an oxidant gas is supplied to the cathode 32. As a result, the stack 1 generates power by a power generation reaction. As the power is generated, the stack 1 generates heat and rises in temperature. The fuel gas and air flow paths are basically the same as those in the prior art, and are omitted because they are not the gist of the present embodiment. When the stack 1 is heated to a high temperature, the power generation performance is deteriorated and the durability of the stack 1 is lowered. Therefore, it is necessary to cool the stack 1 with a coolant such as cooling water. As the refrigerant, pure water having high electrical insulation is preferable. Originally, in the stack 1, the intermediate cell 2C has a higher heat storage property than the end cells 2E and 2F, and therefore the temperature of the intermediate cell 2C tends to be higher than the temperature of the end cells 2E and 2F. On the other hand, since the end cells 2E and 2F have higher heat dissipation than the intermediate cell 2C, the temperatures of the end cells 2E and 2F are likely to be lower than those of the intermediate cell 2C. When the temperature is low, there is a risk of flooding that causes the power generation output to decrease.

  Therefore, according to the present embodiment, the refrigerant (temperature: T1) supplied from the refrigerant supply passage 5 to the refrigerant inlet 13 by the pump 50 is not the relatively low-temperature end cells 2E and 2F because of its high heat dissipation. Then, it is preferentially caused to flow through the intermediate refrigerant passage 70 of the relatively high temperature intermediate cell 2C that is likely to be hot. In this way, not the end cells 2E and 2F but the intermediate cell 2C in the stacking direction of the stack 1 is preferentially cooled. Thus, since the intermediate cell 2C is preferentially cooled by the relatively low-temperature refrigerant not received from the stack 1, the intermediate cell 2C that is easily trapped can be effectively cooled, and excessive temperature rise of the intermediate cell 2C is suppressed. it can. In this sense, it is advantageous for improving the output of the stack 1. Here, the refrigerant that has flowed through the intermediate refrigerant passage 70 and received heat from the intermediate cell 2C and warmed by the heat is increased by β, and the temperature is T2 (T2> T1). Thereafter, the refrigerant warmed by the heat received from the intermediate cell 2C flows through the end refrigerant passages 72 and 73 of the end cells 2E and 2F of the stack 1 to exchange heat with the end cells 2E and 2F. Here, if the temperature of the refrigerant is lower than that of the end cells 2E and 2F, the end cells 2E and 2F are cooled by heat exchange. If the temperature of the refrigerant is higher than that of the end cells 2E and 2F, the end cells 2E and 2F are heated by heat exchange.

  As described above, according to the present embodiment, the refrigerant (temperature: T1) supplied from the refrigerant supply passage 5 to the refrigerant inlet 13 by the pump 50 first flows preferentially into the intermediate refrigerant passage 70 of the intermediate cell 2C. Therefore, it is possible to effectively cool the intermediate cell 2C that tends to rise in temperature. Thereafter, the refrigerant warmed by the heat received from the intermediate cell 2C flows through the end refrigerant passages 72 and 73 of the end cells 2E and 2F of the stack 1 and exchanges heat with the end cells 2E and 2F. An excessive temperature drop in the cells 2E and 2F is suppressed. For this reason, the temperature nonuniformity in the laminated body 10 of the stack 1 is suppressed in the lamination direction (arrow A direction). Therefore, the temperature unevenness in the stacked body 10 is suppressed in all the cells 2 constituting the stack 1. As a result, the power generation unevenness of the tas constituting the stack 1 in the stacking direction (arrow A direction) is suppressed. Therefore, it is possible to contribute to the improvement of the power generation output of the stack 1 and the extension of the life of the stack 1. As described above, an excessive temperature drop in the end cells 2E and 2F having high heat dissipation is suppressed, which is advantageous for suppressing flooding in the end cells 2E and 2F, and can contribute to improvement of the power generation performance of the stack 1.

(Embodiment 2)
FIG. 7 shows a second embodiment. Since this embodiment basically has the same configuration and the same function and effect as those of the first embodiment, FIGS. 1 and 3 to 6 are applied mutatis mutandis. As shown in FIG. 7, an inlet temperature sensor 100 that detects an inlet temperature Tin of the refrigerant supplied to the refrigerant inlet 13 of the first end plate 11 is provided. A first outlet temperature sensor 101 that detects a first outlet temperature Tout1 of the refrigerant discharged from the first refrigerant outlet 14 of the first end plate 11 is provided. A second outlet temperature sensor 102 that detects a second outlet temperature Tout2 of the refrigerant discharged from the second refrigerant outlet 15 of the first end plate 11 is provided. Temperature signals from the inlet temperature sensor 100 and the outlet temperature sensors 101 and 102 are input to the control device 110. In response to the temperature signal or the like, the control device 110 outputs a control signal for adjusting the opening degree of the flow control valve 78.

  The controller 110 opens the flow control valve 78 so that the second outlet temperature Tout2 of the refrigerant becomes plus or minus τ ° C. (for example, τ = 0 to 7 ° C., 0 to 3 ° C.) with respect to the refrigerant inlet temperature Tin. Adjust. In this case, when the second outlet temperature Tout2 becomes excessively higher than the inlet temperature Tin, the opening degree of the flow rate control valve 78 is increased, and the flow rate of the refrigerant heated in the intermediate cell 2C toward the end cells 2E and 2F is decreased. It is preferable to make it. Further, when the second outlet temperature Tout2 becomes excessively lower than the inlet temperature Tin, the opening degree of the flow control valve 78 is decreased, and the refrigerant warmed in the intermediate cell 2C increases the flow rate toward the end cells 2E and 2F. As a result, it is preferable to raise the temperature of the end cells 2E and 2F. By controlling the opening degree of the flow control valve 78 in this way, the second outlet temperature Tout2 of the refrigerant can be made the same or as close as possible to the inlet temperature Tin of the refrigerant. In this case, Tin≈Tout2.

  For example, if the refrigerant inlet temperature Tin is 70 ° C., assuming that the refrigerant is warmed by 5 ° C. by cooling the intermediate cell 2C, the temperature of the refrigerant heated by cooling the intermediate cell 2C is about 75 ° C. Become. At this time, the outlet temperature Tout2 of the refrigerant discharged from the second refrigerant outlet 15 is adapted to the inlet temperature Tin of the refrigerant inlet 13 (Tin≈Tout2, that is, 70 ° C.). If the opening degree is controlled, basically, the upper temperature of each cell 2 (intermediate cell 2C, end cell 2E, 2F) of the stack 1 is set to around 70 ° C., and each cell 2 (intermediate cell 2C, end cell 2E). , 2F), the cell surface temperature distribution in the cell surface direction is obtained with the temperature near 75 ° C. Although the temperature of the refrigerant discharged from the first refrigerant outlet 14 is detected by the temperature sensor 101, since this refrigerant does not pass through the end cells 2E and 2F at both ends, the temperature of this refrigerant is basically 75 ° C. It is considered to be near. If the opening degree of the flow control valve 78 is adjusted as described above, the cell temperature distribution in all the intermediate cells 2C and the end cells 2E and 2F of the stack 1 can be brought close to the above temperature distribution. In addition, 70 degreeC and 75 degreeC are illustrations to the last, and are not limited to this temperature, 75 degreeC and 80 degreeC may be sufficient. Furthermore, 80 degreeC and 85 degreeC may be sufficient.

(Embodiment 3)
This embodiment basically has the same configuration and the same function and effect as the first and second embodiments. In the first embodiment described above, the end refrigerant passage 73 that cools the end cell 2F on the other end side is formed by using the current collector plate 11t. A concave end refrigerant passage 73 may be formed in the end separator 4F. In short, the end refrigerant passage 73 may be any one that can exchange heat with the end cell 2F on the other end side. In the first embodiment, the end refrigerant passage 72 for cooling the end cell 2E on one end side is formed using the end separator 4E. However, the present invention is not limited to this, and the current collector adjacent to the end separator 4E on one end side is used. An end refrigerant passage 72 may be formed in the plate 11r. In short, the end refrigerant passage 72 only needs to exchange heat between the end cells 2E on one end side.

(Embodiment 4)
This embodiment basically has the same configuration and the same function and effect as the first and second embodiments. In the first embodiment described above, the end cell 2E on one end side means the one end cell 2 on the one end side in the stacking direction. The end cell 2F on the other end side means the one end cell 2 on the other end side in the stacking direction. The remaining cell 2 corresponds to the intermediate cell 2C. However, in this embodiment, since the number of stacked cells 2 is as large as 40 to 300, for example, the end cell 2E on one end side is a plurality of cells (arbitrary value of 1 to 6) on one end side in the stacking direction. 2 means. The end cell 2F on the other end side means a plurality of cells (arbitrary value among 1 to 6) on the other end side in the stacking direction. The remaining cell 2 corresponds to the intermediate cell 2C. When the number of stacked cells 2 is N, the upper limit number of end cells 2E on one end side can be {N− (0.6 × N)} / 2. The same applies to the end cell 2F on the other end side.

(Embodiment 5)
This embodiment basically has the same configuration and the same function and effect as the first and second embodiments. However, the flow control valve 78 is provided not on the first refrigerant outlet 14 side but on the second refrigerant outlet 15 side. Also in the present embodiment, since the refrigerant that has been warmed by receiving heat from the intermediate cell 2C flows to the end cells 2E and 2F, an excessive temperature drop in the end cells 2E and 2F is suppressed. Further, if the opening degree of the flow control valve 78 is adjusted, the refrigerant flow rate α1 that reaches the main discharge passage 63 of the refrigerant discharge passage 6 without flowing through the end refrigerant passages 72 and 73 and the end refrigerant passages 72 and 73 flow. The ratio of the refrigerant discharge passage 6 to the main discharge passage 63 via the flow control valve 78 can be adjusted. For this reason, the temperature of the end cells 2E and 2F can be adjusted.

(Embodiment 6)
FIG. 8 shows a sixth embodiment. This embodiment basically has the same configuration and the same function and effect as the first and second embodiments. However, the flow control valve 78, the first discharge passage 61, and the first refrigerant outlet 14 are not equipped. Originally, since the end cells 2E and 2F have higher heat dissipation than the intermediate cell 2C, the temperature of the end cells 2E and 2F tends to be lower than the temperature of the intermediate cell 2C. At low temperatures, flooding may occur. Therefore, according to the present embodiment, as in the first embodiment, the refrigerant (temperature: T1) supplied from the refrigerant supply passage 5 to the inlet is not passed through the end cells 2E and 2F of the stack 1, It flows preferentially through the 2C intermediate refrigerant passage 70 to cool the intermediate cell 2C preferentially. The refrigerant that has flowed through the intermediate refrigerant passage 70 and received heat from the intermediate cell 2C and warmed up by β is raised by β by the heat reception to a temperature T2 (T2> T1). Next, the refrigerant warmed by the heat received from the intermediate cell 2C is passed through the end refrigerant passages 72 and 73 of the end cells 2E and 2F of the stack 1 to exchange heat between the end cells 2E and 2F. The refrigerant is discharged from the second refrigerant outlet 15 to the refrigerant discharge passage 6. Also in the present embodiment, since the refrigerant that has been warmed by receiving heat from the intermediate cell 2C flows to the end cells 2E and 2F, an excessive temperature drop in the end cells 2E and 2F is suppressed.

(Other)
The above-mentioned drawings show the concept of the embodiment, and the end refrigerant passage 72 is formed by forming a passage through which the refrigerant flows in the end separator 4E, but the end separator 4E and the current collector plate 11r are mutually connected. It is good also as the end refrigerant path 72 by forming the channel | path through which a refrigerant | coolant flows between the surfaces which oppose. In short, the end refrigerant passage 72 only needs to exchange heat between the end cells 2E on one end side with the refrigerant. The end refrigerant passage 73 is formed by forming a passage through which the refrigerant flows in the current collector plate 11t. However, the end refrigerant passage 73 forms a passage through which the refrigerant flows between the opposing surfaces of the end separator 4F and the current collector plate 11t. The end refrigerant passage 73 may be used. In short, the end refrigerant passage 73 only needs to exchange heat between the end cells 2F on the other end side with the refrigerant. The flow control valve 78 may be a three-way valve connected to the first discharge passage 61, the second discharge passage 62, and the main discharge passage 63. The intermediate refrigerant passage 70 causes the refrigerant to flow downward, and the end refrigerant passages 72 and 73 cause the refrigerant to flow upward. However, the present invention is not limited to this. May be allowed to flow downward. Furthermore, in the stack 1, the fuel may flow downward or upward. Similarly, the air may flow downward or upward. Therefore, although the first refrigerant outlet 14 is provided on the lower side of the stack 1, it may be provided on the upper side. The refrigerant inlet 13 and the second refrigerant outlet 15 are provided on the upper side of the stack 1, but may be provided on the lower side. In the above-described embodiment, in the stack 1, the cells 2 are arranged side by side along the horizontal direction. However, the present invention is not limited to this, and the cells 2 may be arranged side by side along the height direction. good. The stack 1 only needs to cool the cell 2 with a coolant such as cooling water. The present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist.

  1 is a stack, 10 is a laminate, 11 is a first end plate, 12 is a second end plate, 13 is a refrigerant inlet, 14 is a first refrigerant outlet, 15 is a second refrigerant outlet, 2 is a cell, 2C is an intermediate cell 2E and 2F are end cells, 4 is a separator, 5 is a refrigerant supply passage, 50 is a pump, 6 is a refrigerant discharge passage, 7 is a refrigerant passage structure, 70 is an intermediate refrigerant passage, 72 and 73 are end refrigerant passages, and 78 is A flow control valve (flow control element), 81 is a first manifold hole, 82 is a second manifold hole, 83 is a third manifold hole, 88 is a surface passage, 100 is an inlet temperature sensor, 101 is a first outlet temperature sensor, 102 Denotes a second outlet temperature sensor, and 110 denotes a control device.

Claims (4)

A stack having a refrigerant passage structure that is formed by laminating a plurality of cells having a membrane electrode assembly and separators sandwiching both sides of the membrane electrode assembly in the thickness direction and that allows a refrigerant to flow;
A refrigerant supply passage communicating with an inlet of the refrigerant passage structure of the stack;
A refrigerant discharge passage communicating with an outlet of the refrigerant passage structure of the stack,
The refrigerant passage structure of the stack is
An intermediate refrigerant passage of an intermediate cell that exists in the middle of the stacking direction of the stack, and an end refrigerant passage of an end cell that exists at an end of the stacking direction, and
The refrigerant supplied from the refrigerant supply passage is caused to flow through the intermediate refrigerant passage to cool the intermediate cell, and the refrigerant that has flowed through the intermediate refrigerant passage and received heat from the intermediate cell is heated. A fuel cell stack device having a structure for flowing through a passage and exchanging heat with the end cell. A stack having a refrigerant passage structure formed by laminating a plurality of cells having a membrane electrode assembly and separators sandwiching both sides of the membrane electrode assembly in the thickness direction and flowing a refrigerant; and
A refrigerant supply passage communicating with an inlet of the refrigerant passage structure of the stack;
A refrigerant discharge passage communicating with an outlet of the refrigerant passage structure of the stack,
The refrigerant passage structure of the stack is
The intermediate refrigerant passage of the intermediate cell that exists in the middle of the stacking direction of the stack, the end refrigerant passage of the end cell that exists at the end of the stacking direction, the flow through the intermediate refrigerant passage, but not through the end refrigerant passage A flow rate control element for adjusting a ratio between the refrigerant flow rate α1 reaching the refrigerant discharge passage and the refrigerant flow rate α2 flowing through the intermediate refrigerant passage and the end refrigerant passage and reaching the refrigerant discharge passage, and ,
The refrigerant supplied from the refrigerant supply passage is caused to flow through the intermediate refrigerant passage to cool the intermediate cell, and the refrigerant received through the intermediate refrigerant passage and heated from the intermediate cell is allowed to flow through the end refrigerant passage. A fuel cell stack device having a structure for exchanging heat with the end cell.   3. The stack according to claim 2, wherein the stack flows from the refrigerant supply passage to a first refrigerant inlet for supplying a refrigerant to an inlet of the refrigerant passage structure of the stack, and flows from the intermediate cell through the intermediate refrigerant passage of the stack. A first refrigerant outlet for flowing the received and warmed refrigerant into the refrigerant discharge passage without flowing into the end refrigerant passage of the end cell; and a refrigerant which is warmed by receiving heat from the intermediate cell through the intermediate refrigerant passage And a second refrigerant outlet for flowing the refrigerant into the refrigerant discharge passage through the end refrigerant passage of the end cell.   The inlet temperature sensor for detecting an inlet temperature Tin of the refrigerant at the first refrigerant inlet, a first outlet temperature sensor for detecting an outlet temperature Tout1 of the refrigerant discharged from the first refrigerant outlet, (2) a second outlet temperature sensor that detects the outlet temperature Tout2 of the refrigerant discharged from the refrigerant outlet, and the outlet temperature Tout2 becomes plus or minus τ ° C. (τ = 0 to 5 ° C.) with respect to the inlet temperature Tin. A fuel cell stack device comprising: a control device that adjusts an opening degree of the flow rate control element;

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