JP5186845B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell.

  A fuel cell is known in which a plurality of fuel cells each including an electrolyte membrane having an anode and a cathode formed on the surface are stacked. In this fuel cell, water is generated at the cathode by an electrochemical reaction (see Patent Document 1 below).

JP 2004-288509 A

  However, in the fuel cell, water generated at the cathode is condensed in the gas flow path of the fuel cell, and the condensed water may hinder gas flow. In the fuel cell, the amount of gas used for the electrochemical reaction is insufficient, and the voltage may decrease accordingly. As a result, there is a concern that the power generation efficiency of the fuel cell may decrease due to an increase in the number of such fuel cells.

  The present invention has been made to solve the above-described problems, and aims to suppress a decrease in the voltage of a predetermined fuel cell in a fuel cell and to suppress a decrease in power generation efficiency of the fuel cell. To do.

  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 or application examples.

[Application Example 1]
A fuel cell in which a plurality of fuel cells each having an electrolyte membrane having an anode formed on one surface and a cathode formed on the other surface is laminated, and is disposed at one end of the fuel cell on the outside of the fuel cell. A first fuel cell provided with the anode is disposed toward the other end of the fuel cell, and a second fuel cell provided with the cathode is disposed toward the outside of the fuel cell. In addition, the gist of the present invention is to further include a temperature raising unit that makes the temperature of the first fuel cell higher than the temperature of the second fuel cell.

  According to the fuel cell having the above configuration, it is possible to suppress a decrease in the voltage of the first fuel cell, and as a result, it is possible to suppress a decrease in power generation efficiency of the fuel cell.

[Application Example 2]
In the fuel cell according to Application Example 1, each fuel cell is stacked so that the anode and the cathode are alternately arranged, and the temperature raising portion is in the vicinity of the one end of the fuel cell. The fuel battery cell, wherein the fuel battery cell is located in the vicinity of the other end of the fuel cell, and has an average cell temperature of a plurality of fuel battery cells including the first fuel battery cell. A fuel cell characterized in that the temperature is higher than the average cell temperature of a plurality of fuel cells including the second fuel cell.

  If it does in this way, it can control that the voltage of the fuel cell near one edge part of a fuel cell falls, and, as a result, can suppress the power generation efficiency fall of a fuel cell.

[Application Example 3]
In the fuel cell according to Application Example 1 or Application Example 2, a refrigerant supply manifold for supplying a coolant for cooling the fuel cell to each fuel cell, and a plate belonging to the one end of the fuel cell And a manifold for collecting the refrigerant after cooling each fuel battery cell and discharging the collected refrigerant to the outside of the fuel cell, and at least a part of the temperature riser, A fuel cell comprising: a refrigerant discharge manifold formed in a direction along a plate surface of the plate-like member in order to cause the collected refrigerant to flow inside the plate-like member.

  In this way, without using another temperature raising device, the refrigerant discharge manifold is used to suppress a decrease in the voltage of the fuel cell in the vicinity of one end, thereby suppressing a decrease in power generation efficiency of the fuel cell. can do. Therefore, it is possible to reduce the weight of the fuel cell, suppress the enlargement of the fuel cell, simplify the structure, and reduce the manufacturing cost.

[Application Example 4]
The fuel cell according to Application Example 3, wherein the plate-like member is an insulator.

  In this way, since the refrigerant after cooling the fuel cells, that is, the refrigerant whose temperature has been increased, flows into the insulator, the insulator can be warmed. As a result, the fuel cell in the vicinity of one end can be warmed via the insulator, the voltage of the fuel cell in the vicinity of the one end is suppressed from decreasing, and the decrease in power generation efficiency of the fuel cell is suppressed. can do.

[Application Example 5]
5. The fuel cell according to any one of application examples 1 to 4, wherein a heater is provided on the one end side of the fuel cell as the temperature raising portion.

  If it does in this way, it can control that the voltage of the fuel cell near one edge part falls, and can control the power generation efficiency fall of a fuel cell.

[Application Example 6]
The fuel cell according to any one of Application Examples 1 to 5, further comprising a plate-like member belonging to the one end of the fuel cell, wherein the one end or the one end is used as the temperature raising unit. A fuel cell comprising a heat insulating material covering at least one of the fuel cells in the vicinity of the portion.

  If it does in this way, it can control that the voltage of the fuel cell near one edge part falls, and can control the power generation efficiency fall of a fuel cell.

  Note that the present invention can be realized in the form of other device inventions such as a fuel cell system and a temperature raising device in addition to the fuel cell described above. Further, the present invention is not limited to such a device invention, and can be realized as a method invention such as a method for raising the temperature of a fuel cell.

A. First embodiment:
A1. Overall configuration of the fuel cell system of the first embodiment:
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell system 1000 as an embodiment of the present invention. The fuel cell system 1000 mainly includes a fuel cell 100 that is a main body of power generation, a hydrogen supply unit 22, a blower 24, a hydrogen circulation pump 60, a refrigerant circulation pump 70, a radiator 77, and a gas-liquid separator 65. And a pressure regulating valve 26.

  The fuel cell 100 is a polymer electrolyte fuel cell and has a stack structure in which a plurality of fuel cells are stacked. Details of the fuel cell 100 will be described later.

  The hydrogen supply unit 22 stores hydrogen supplied as fuel gas to the fuel cell 100 (a fuel gas supply manifold MHI described later). As the hydrogen supply unit 22, for example, a hydrogen cylinder that compresses and stores hydrogen gas, or a hydrogen tank including a hydrogen storage alloy can be used. The hydrogen supply unit 22 supplies fuel gas to the fuel cell 100 via the hydrogen supply path 23. The pressure adjustment valve 26 is provided on the hydrogen supply path 23 and adjusts (depressurizes) the pressure of hydrogen supplied from the hydrogen supply unit 22 to the fuel cell 100 to a predetermined pressure. Such hydrogen pressure adjustment is not performed by the single pressure adjustment valve 26, but may be performed by sequentially reducing the pressure using a plurality of valves.

  The fuel gas discharged from the fuel cell 100 (a fuel gas discharge manifold MHO described later) is discharged to the fuel gas discharge path 28. A fuel gas bypass passage 29 is connected to the fuel gas discharge passage 28, and a hydrogen circulation pump 60 is provided on the fuel gas bypass passage 29. The fuel gas discharged to the fuel gas discharge path 28 is guided to the fuel gas bypass path 29 by the hydrogen circulation pump 60 and flows into the hydrogen supply path 23 again. Thus, the remaining hydrogen in the fuel gas discharged from the fuel cell 100 is a flow path (hereinafter referred to as a circulation) composed of a part of the hydrogen supply path 23, the fuel gas bypass path 29, and the flow path in the fuel cell 100. It is circulated in the flow path) and again subjected to the electrochemical reaction.

  Further, a gas-liquid separator 65 is provided in the fuel gas bypass passage 29. As the electrochemical reaction proceeds, water is generated at the cathode, but part of the generated water moves to the anode side through the electrolyte membrane of the fuel cell 100 and is vaporized into the fuel gas. Therefore, in the fuel gas circulating in the circulation channel, the water vapor concentration gradually increases. The gas-liquid separator 65 condenses water vapor contained in the fuel gas that circulates in the circulation flow path, and reduces the water vapor concentration in the fuel gas. The gas-liquid separator 65 is provided with a valve 64. By opening the valve 64, water condensed in the gas-liquid separator 65 is exposed to the outside via the fuel gas discharge path 28. Discharged. Note that by opening the valve 64 at a predetermined timing, a part of the fuel gas circulating in the circulation flow path along with the condensed water is also discharged to the outside, whereby the impurity concentration ( An increase in the concentration of nitrogen or the like that has moved from the cathode side to the anode side through the electrolyte membrane is suppressed.

  The blower 24 is a device for supplying air as an oxidizing gas to the fuel cell 100 (an oxidizing gas supply manifold MAI described later). The blower 24 supplies an oxidizing gas to the fuel cell 100 via the oxidizing gas supply path 25. The oxidizing gas discharged from the fuel cell 100 (an oxidizing gas discharge manifold MAO described later) is discharged outside the fuel cell 100 through the oxidizing gas discharge path 27.

  In the fuel cell 100, a refrigerant circulation passage 75 is connected to a refrigerant supply manifold MWI and a refrigerant discharge manifold MWO, which will be described later. A radiator 77 and a refrigerant circulation pump 70 are provided on the refrigerant circulation channel 75. The refrigerant flowing through the refrigerant circulation passage 75 is circulated through the refrigerant circulation passage 75 and the fuel cell 100 by the refrigerant circulation pump 70. The refrigerant that has cooled the fuel cell 100 is discharged from the refrigerant discharge manifold MWO and then cooled by the radiator 77. Then, the refrigerant is again introduced into the refrigerant supply manifold MWI and used for cooling the fuel cell 100. As the refrigerant, water, antifreeze water such as ethylene glycol, air, or the like can be used.

A2. Fuel cell configuration:
FIG. 2 is a schematic external configuration diagram of the fuel cell 100. The fuel cell 100 includes an anode side end plate EPA, an anode side insulator ISA, an anode side terminal TMA, a plurality of fuel cell SL and a plurality of refrigerant separators SPW, a cathode side terminal TMC, a cathode side insulator ISC, from the left end in FIG. The cathode side end plate EPC is laminated in this order. Fuel cell SL and refrigerant separator SPW are alternately stacked.

  Here, in the fuel cell 100 of the present embodiment, an end portion closer to the anode of each fuel cell SL, which will be described later, is also referred to as an anode side end portion, and an end portion closer to the cathode side of each fuel cell SL. Also called the cathode side end. The anode side end portion is on the negative electrode side, and specifically includes an anode side end plate EPA, an anode side insulator ISA, and an anode side terminal TMA. The cathode side end portion is on the positive electrode side, and specifically includes a cathode side end plate EPC, a cathode side insulator ISC, and a cathode side terminal TMC.

  Although not shown, the fuel cell 100 is fastened and held by a tension plate or the like with a predetermined pressing force applied in the stacking direction. In the fuel cell 100, the x direction, the y direction, and the z direction are defined as shown in FIG. The direction in which the fuel cell SL and the refrigerant separator SPW are stacked is also referred to as a stacking direction. Furthermore, a direction orthogonal to the stacking direction and along the fuel cell SL is also referred to as a plane direction.

  Each end plate is made of metal such as steel in order to ensure rigidity. Each terminal is formed of a gas impermeable conductive member such as dense carbon or a copper plate. The anode-side terminal TMA includes an anode-side terminal TA that serves as a minus terminal, and the cathode-side terminal TMC includes a cathode-side terminal TC that serves as a plus terminal. Each insulator is formed of an insulating member such as rubber or resin.

  The fuel cell 100 is supplied with an oxidizing gas, and an oxidizing gas supply manifold MAI for introducing the oxidizing gas into each in-cell oxidizing gas flow path, which will be described later, and an oxidizing gas discharged from each in-cell oxidizing gas flow path. Oxidizing gas discharge manifold MAO to be discharged, fuel gas is supplied, and fuel gas supply manifold MHI for introducing fuel gas into each in-cell fuel gas flow path, which will be described later, is discharged from each in-cell fuel gas flow path. Fuel gas discharge manifold MHO in which fuel gas collects, refrigerant supply manifold MWI that is supplied with refrigerant and distributes the refrigerant to the inter-cell refrigerant flow path, and refrigerant discharge in which the refrigerant discharged from the inter-cell refrigerant flow path collects And a manifold MWO.

  Each of these manifolds has an opening at the anode side end of the fuel cell 100 as shown in FIG. The opening of the fuel gas supply manifold MHI is connected to the hydrogen supply path 23 and fuel gas is introduced. The opening of the fuel gas discharge manifold MHO is connected to the fuel gas discharge path 28 and discharges the fuel gas. The opening of the oxidizing gas supply manifold MAI is connected to the oxidizing gas supply path 25, and the oxidizing gas is introduced. The opening of the oxidizing gas discharge manifold MAO is connected to the oxidizing gas discharge path 27 and discharges the oxidizing gas. The openings of the refrigerant supply manifold MWI and the refrigerant discharge manifold MWO are connected to the refrigerant circulation passage 75, and the refrigerant is supplied and discharged.

  FIG. 3 is an exploded perspective view showing the state of the fuel cell SL as a structural unit of the fuel cell 100 and the refrigerant separator SPW. The fuel cell SL includes a membrane electrode assembly (hereinafter referred to as “MEA”), an anode-side separator SPA, and a cathode-side separator SPC. The MEA 10 includes an electrolyte membrane 40, cathodes 41 and anodes 42, which are electrodes, and gas diffusion layers 43 and 44. The electrolyte membrane 40 having the cathode 41 and the anode 42 formed on the surface thereof is connected to the gas diffusion layers 43, 44. The fuel cell SL is configured such that the MEA 10 is further sandwiched between an anode side separator SPA and a cathode side separator SPC.

  The electrolyte membrane 40 is a proton conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, and exhibits good electrical conductivity in a wet state. The cathode 41 and the anode 42 include a catalyst such as platinum or a platinum alloy supported on a conductive carrier such as carbon particles. The gas diffusion layers 43 and 44 can be formed of a conductive member having gas permeability, for example, carbon paper or carbon cloth, and serves as a gas flow path for an electrochemical reaction and collects current. .

  The anode-side separator SPA and the cathode-side separator SPC are formed of a gas-impermeable conductive member, for example, dense carbon that has been compressed by gas and impermeable to gas, baked carbon, or a press-molded metal plate. . The anode-side separator SPA and the cathode-side separator SPC are members that form the wall surface of a gas flow path through which a reaction gas (a fuel gas containing hydrogen or an oxidizing gas containing oxygen) flows. An uneven shape is formed for forming the. A groove 63 is formed on the surface of the anode-side separator, and an in-cell fuel gas flow path that is a flow path of fuel gas is formed between the anode side separator and the MEA 10. The cathode-side separator has a groove 62 formed on the surface thereof, and forms an in-cell oxidizing gas channel, which is an oxidizing gas channel, between the cathode side separator and the MEA 10.

  A through hole 87 is formed in the refrigerant separator SPW. By alternately stacking the fuel cells SL and the refrigerant separators SPW, the through holes 87 form an inter-cell refrigerant flow path between the fuel cells SL.

  Separator SPA, SPC, SPW is provided with a plurality of holes at positions corresponding to each other near its outer periphery. When the fuel cells are assembled by laminating the separators SPA, SPC, SPW together with the MEA 10, the holes provided at the corresponding positions of the separators overlap each other and flow through the inside of the fuel cell in the separator laminating direction. Form. That is, among the holes provided in each separator, the hole 85 and the hole 86 communicate with a groove 63 provided on the separator surface in order to form an in-cell fuel gas flow path. Further, the hole 83 and the hole 84 communicate with a groove 62 provided on the separator surface in order to form an in-cell oxidizing gas flow path. Furthermore, the hole part 81 and the hole part 82 are connected with the through-hole 87 provided in the separator surface in order to form the inter-cell refrigerant flow path. In this case, the hole 85 forms the fuel gas supply manifold MHI, the hole 86 forms the fuel gas discharge manifold MHO, the hole 83 forms the oxidizing gas supply manifold MAI, and the hole 84. Forms an oxidizing gas discharge manifold MAO. Further, the hole portion 81 forms a refrigerant supply manifold MWI, and the hole portion 82 forms a refrigerant discharge manifold MWO. Therefore, the in-cell fuel gas channel, the in-cell oxidizing gas channel, and the inter-cell refrigerant channel are connected in parallel through the manifold in the fuel cell.

  FIG. 4 is a diagram for explaining details of the refrigerant discharge manifold MWO in the present embodiment. 4A is a side view of the fuel cell 100 (view of the fuel cell 100 viewed in the z direction), and FIG. 4B is a front view of the anode insulator ISA (the anode insulator ISA is shown). (A view seen in the x direction). As shown in FIG. 4 (A), the refrigerant discharge manifold MWO in the present embodiment penetrates the fuel cell SL and the refrigerant separator SPW in the stacking direction (x direction), and FIGS. 4 (A) and 4 (B). As shown in FIG. 4, the anode-side insulator ISA is formed so as to penetrate in a meandering manner along the surface direction and reach the opening. Thereby, in the refrigerant | coolant discharge manifold MWO in the anode side insulator ISA, the refrigerant | coolant heated up by heat exchange in each fuel cell SL will flow.

A3. Relationship between temperature distribution and battery performance:
In a fuel cell having a conventional stack structure, it is generally known that the internal temperature is lower in the fuel cell near the both ends where heat exchange with the outside is likely to occur. When the temperature decreases in this way, condensed water is generated in the gas flow path by decreasing the saturated water vapor pressure, and the gas flow may be inhibited by the condensed water. Therefore, conventionally, it has been considered that a voltage drop due to the inhibition of the gas flow by the condensed water occurs in the fuel cell near the both ends where the temperature becomes lower.

  On the other hand, the inventor of the present application has found as a new finding that a voltage drop is likely to occur in the fuel cell in the vicinity of the anode side end portion, in particular, at both ends where the internal temperature is lowered. That is, in the fuel cell in which the in-cell fuel gas channel and the in-cell oxidizing gas channel are connected in parallel in the fuel cell via the manifold, as in the fuel cell 100 of the present embodiment, As shown in FIG. 5, when the outside air temperature is low, the amount of condensed water inside the fuel cell only in the vicinity of the anode side end portion increases, and as a result, the voltage drop of the fuel cell is particularly noticeable. Admitted.

FIG. 5 is an explanatory diagram showing the distribution of the amount of condensed water inside the fuel cell while showing the relative position of each fuel cell in the fuel cell having the conventional stack structure on the horizontal axis. The fuel cell having the condensed water amount distribution shown in FIG. 5 is a conventionally known stack-structure fuel cell, in which the refrigerant discharge manifold MWO includes the anode-side insulator ISA and the other members (fuel cell SL, refrigerant separator SPW). , Terminals, etc.) are simply penetrated in the stacking direction. FIG. 5 shows that when the outside air temperature is 60 ° C., 20 ° C., and −10 ° C., a large excess amount of both fuel gas and oxidizing gas is allowed to flow through the fuel cell. The results are shown when power is generated for 1 hour under the conditions of / cm ² .

  In this way, the voltage drop is particularly likely to occur in the fuel cell near the anode side end, because of the small temperature difference existing between both sides of the electrolyte membrane in the group of fuel cells arranged near the end. This is considered to be due to the difference in properties between the fuel gas and the oxidizing gas. When the fuel cell generates power, it is considered that condensed water is first generated in the gas flow path on the lower temperature side due to the small temperature difference. That is, even within the same fuel battery cell, a slight temperature difference occurs between the oxidizing gas flow path in the fuel battery cell and the fuel gas flow path in the fuel battery cell. The gas channel has a lower temperature. When a temperature difference occurs in this way, even if both the fuel gas and the oxidizing gas have substantially saturated vapor pressure, the gas inside the fuel cell in the end portion side where the temperature is slightly low By being cooled slightly on the channel wall, condensed water begins to be generated on the channel wall. The gas at the lower temperature side is agitated and contacts the electrolyte membrane. At this time, the electrolyte membrane is at an intermediate temperature between the gas flow paths on both sides, so the gas in contact is slightly heated. The saturated vapor pressure rises slightly and deprives the electrolyte membrane of moisture. The gas that has received moisture from the electrolyte membrane is stirred again and cooled by the flow path wall to generate condensed water again. On the other hand, the gas flowing through the gas flow path in the fuel cell on the inner side where the temperature is slightly high is agitated and comes into contact with the electrolyte membrane. Then, condensed water is generated on the electrolyte membrane. The generated condensed water moves in the electrolyte membrane to the opposite surface side (the gas flow path side having a slightly low temperature). By repeating such a process, it is considered that condensed water is more likely to be generated in the gas flow path in the fuel cell on the slightly lower temperature side.

  When liquid water is generated in the flow path on the low temperature side as described above, if the flow path on the low temperature side is a flow path for fuel gas, the difference in properties between the fuel gas and the oxidizing gas Therefore, it is considered that liquid water tends to stay particularly in the flow path. This difference in the properties of gas is a difference in the force of flowing liquid water, and the force of flowing liquid water is influenced by the flow rate of each gas, for example. The gas flow rate is generally faster in the oxidizing gas than in the fuel gas, which will be described below. The electrochemical reaction that proceeds in the fuel cell can be expressed by the following equations (1) to (3). Formula (1) represents the reaction on the anode side, Formula (2) represents the reaction on the cathode side, and Formula (3) represents the reaction that proceeds in the entire fuel cell.

H ₂ → 2H ⁺ + 2e ⁻ (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
H ₂ + (1/2) O ₂ → H ₂ O (3)

  As shown in the equation (3), the ratio of the hydrogen amount and the oxygen amount theoretically required when the fuel cell generates a predetermined amount of power is 2: 1. When hydrogen is used as the fuel gas and air is used as the oxidizing gas as in this embodiment, the proportion of oxygen in the air is about 20%. The ratio of gas amounts is approximately 2: 5. Therefore, if the excess ratio when supplying gas to the fuel cell (the ratio of the amount actually supplied to the theoretically required amount) is the same for the fuel gas and the oxidizing gas, the inlet of the fuel cell The flow rate of the oxidizing gas supplied can be said to be about 2.5 times the flow rate of the fuel gas. As described above, generally, the flow rate of the oxidizing gas supplied to the fuel cell is faster than the flow rate of the fuel gas. Therefore, the oxidizing gas has a stronger force for blowing off the condensed water.

  More specifically, it can be considered that the force by which the gas blows off the liquid water depends on, for example, the momentum of the gas and the viscous force. Since momentum is the product of mass and velocity, the momentum of the gas can be compared as the product of the molecular weight of the gas and the flow velocity. The molecular weight of hydrogen is 2, whereas the average molecular weight of air is about 29. As described above, the gas flow rate at the inlet supplied to the fuel cell when the excess ratio is the same is approximately 2.5 times that of the fuel gas for the oxidizing gas. Therefore, the ratio of the momentum of the oxidizing gas to the momentum of the fuel gas is 1: 36.25 as shown in the following equation (4), and the force by which the fuel gas jumps off the liquid water is about 36 minutes of the oxidizing gas. It can be considered that there is only one of them.

  2 × 1: 29 × 2.5 = 2: 72.5 = 1: 36.25 (4)

Moreover, the viscous force of gas can be grasped as a force by which gas drags liquid water with stickiness, and can be compared as the product of the viscosity coefficient of gas and the flow velocity. The viscosity coefficient of hydrogen at 20 ° C. and 1 atm is 8.8 × 10 ⁻⁶ [Pa · s], whereas the viscosity coefficient of air is 18.2 × 10 ⁻⁶ [Pa · s]. . As described above, the gas flow rate at the inlet supplied to the fuel cell when the excess ratio is the same is approximately 2.5 times that of the fuel gas for the oxidizing gas. Therefore, the ratio of the viscous force of the oxidizing gas to the viscous force of the fuel gas is 1: 5.2 as shown in the following equation (5), and the force by which the fuel gas drags the liquid water is about 5 times that of the oxidizing gas. It can be considered that there is only a fraction.

  8.8 × 1: 18.2 × 2.5 = 8.8: 45.5≈1: 5.2 (5)

  As described above, in the fuel cells in the vicinity of both ends of the fuel cell, condensed water begins to be generated in the gas flow channel in the fuel cell on the end portion having a lower temperature due to a subtle temperature difference. . And in the flow path of the fuel gas whose power for discharging the condensed water is weaker than that of the oxidizing gas, the generated condensed water cannot be discharged and the condensed water gradually stays. In this way, it is considered that a voltage drop occurs in the fuel battery cell near the anode side end portion due to the retention of the condensed water in the in-cell fuel gas flow path.

  On the other hand, in the fuel cell 100 of the present embodiment, the refrigerant discharge manifold MWO is formed so as to penetrate the anode-side insulator ISA along the surface direction. In this way, when the fuel cell SL is cooled and the heated refrigerant flows through the anode insulator ISA, the anode insulator ISA can be warmed, and accordingly, the fuel cell in the vicinity of the anode side end portion. The cell SL can be warmed. Therefore, the generation of condensed water can be suppressed in the fuel cell SL in the vicinity of the anode side end, and the voltage drop caused by it can also be suppressed. As a result, in the fuel cell 100, it is possible to suppress the generation of the fuel cell SL having a locally low voltage, and the power generation efficiency of the entire fuel cell 100 can be improved.

  Further, in the fuel cell 100 of the present embodiment, a mechanism for raising the temperature at the cathode side end portion is not provided, and a mechanism for raising the temperature is provided only at the anode side end portion. Simplification of the structure, reduction of weight, suppression of enlargement, or reduction of manufacturing costs can be realized.

  The fuel cell SL corresponds to the fuel cell in the claims, and the refrigerant discharge manifold MWO corresponds to the temperature raising unit in the claims. The anode side end corresponds to one end in the claims, and the cathode side end corresponds to the other end in the claims.

B. Second embodiment:
FIG. 6 is a side view of the fuel cell 100A of the second embodiment. The fuel cell system 1000A of the second embodiment basically has the same structure as the fuel cell system 1000 of the first embodiment, but differs from the fuel cell system 1000 of the first embodiment in the following points. . The fuel cell 100 according to the first embodiment warms the fuel cell SL in the vicinity of the anode side end portion by flowing the refrigerant whose temperature is increased in each fuel cell SL along the surface direction inside the anode insulator ISA. However, the fuel cell 100A of this embodiment includes the heater HT, and the heater HT warms the fuel cell SL near the anode side end. Specifically, in the fuel cell 100A, as shown in FIG. 6, the heater HT is disposed outside the anode side end plate EPA, and includes the anode side end plate EPA, the anode side insulator ISA, and the anode side terminal TMA. Then, the fuel cell SL near the anode side end is warmed.

  If it does in this way, it will become possible to warm the fuel cell SL near the anode side end by the heater HT. Therefore, the generation of condensed water can be suppressed in the fuel cell SL in the vicinity of the anode side end, and the voltage drop caused by it can also be suppressed. As a result, in the fuel cell 100A, it is possible to suppress the generation of the fuel cell SL having a locally low voltage, and the power generation efficiency of the entire fuel cell 100A can be improved.

C. Third embodiment:
FIG. 7 is a side view of the fuel cell 100B of the third embodiment. The fuel cell system 1000B of the third embodiment basically has the same structure as the fuel cell system 1000 of the first embodiment, but differs from the fuel cell system 1000 of the first embodiment in the following points. . The fuel cell 100 according to the first embodiment warms the fuel cell SL in the vicinity of the anode side end portion by flowing the refrigerant whose temperature is increased in each fuel cell SL along the surface direction inside the anode insulator ISA. However, the fuel cell 100B of the present embodiment includes the heat insulating material HS, and the heat insulating material HS suppresses the temperature drop of the fuel cell SL near the anode side end. Specifically, in the fuel cell 100B, as shown in FIG. 7, the heat insulating material HS includes the anode side end plate EPA, the anode side insulator ISA, the anode side terminal TMA, and the fuel cell SL near the anode side end. It arrange | positions so that (7) may be covered. In addition, glass wool, rock wool, etc. can be used for the heat insulating material HS, for example. The number of fuel cells SL covered with the heat insulating material HS is determined based on the specific design of the fuel cell 100B.

  In this way, the fuel cells SL in the vicinity of the anode side end are substantially insulated, and the temperature of these fuel cells SL is prevented from lowering, compared with the fuel cell SL in the vicinity of the cathode side end. Thus, it is possible to suppress the temperature from becoming relatively low. Therefore, the generation of condensed water can be suppressed in the fuel cell SL in the vicinity of the anode side end, and the voltage drop caused by it can also be suppressed. As a result, in the fuel cell 100B, it can suppress that the fuel cell SL with a low voltage locally arises, and can improve the electric power generation efficiency of the fuel cell 100B whole.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
The fuel cell 100 according to the first embodiment causes the fuel cell SL in the vicinity of the anode side end portion to flow in the surface direction inside the anode side insulator ISA by causing the refrigerant whose temperature is increased in each fuel cell SL to flow. Although warming is performed, the present invention is not limited to this. For example, the refrigerant discharge manifold MWO is formed so as to penetrate the anode-side terminal TMA or the anode-side end plate EPA in the surface direction, and the refrigerant whose temperature is increased in each fuel cell SL is moved along the surface direction in the inside thereof. The fuel cell SL near the anode side end may be warmed by flowing. Even if it does in this way, there can exist an effect similar to the said Example.

C2. Modification 2:
In the fuel cell 100A of the second embodiment (FIG. 6), the heater HT is disposed outside the anode side end plate EPA, and the anode side end plate EPA, the anode side insulator ISA, and the anode side terminal TMA are used. Although the fuel cell SL in the vicinity of the anode side end is heated, the present invention is not limited to this. For example, the heater HT is disposed between the anode side end plate EPA and the anode side insulator ISA so as to warm the fuel cell SL near the anode side end via the anode side insulator ISA and the anode side terminal TMA. May be. Further, the heater HT may be disposed between the anode-side insulator ISA and the anode-side terminal TMA so as to warm the fuel cell SL near the anode-side end via the anode-side terminal TMA. In this case, the heater HT is covered with an insulating member. Even if it does as mentioned above, there can exist an effect similar to the said Example.

C3. Modification 3:
The fuel cell 100B (FIG. 7) of the third embodiment includes a heat insulating material HS, an anode side end plate EPA, an anode side insulator ISA, an anode side terminal TMA, and fuel cell cells SL (7 However, the present invention is not limited to this. For example, the heat insulating material HS may cover only the anode side end plate EPA, only the anode side insulator ISA, only the anode side terminal TMA, or only the fuel cell SL near the anode side end. Good. The heat insulating material HS may cover the anode side end plate EPA and the anode side insulator ISA, or may cover the anode side end plate EPA, the anode side insulator ISA, and the anode side terminal TMA. Even if it does in this way, there can exist the effect of the said Example.

C4. Modification 4:
Although the fuel cell of the said Example is comprised so that the fuel cell SL and the separator for refrigerant | coolants SPW may be piled up alternately, this invention is not limited to this. For example, in the separator of the fuel cell, a groove may be formed on the surface opposite to the surface forming the in-cell gas flow path, and the fuel cell may be stacked using this separator. In this case, the space formed by the grooves between the fuel cells serves as the refrigerant flow path. Further, the separator may be a so-called three-layer laminated separator, and the fuel cell may be configured by alternately laminating the three-layer laminated separator and a laminated body having an MEA or a porous channel. Good. In addition, this laminated body functions as a fuel battery cell. Even a fuel cell having such a configuration can achieve the same effects as the above-described embodiment.

It is a block diagram showing schematic structure of the fuel cell system 1000 as one Example of this invention. 1 is a schematic external configuration diagram of a fuel cell 100. FIG. 2 is an exploded perspective view showing the state of fuel cell SL and refrigerant separator SPW, which are constituent units of fuel cell 100. FIG. It is a figure for demonstrating the detail of the refrigerant | coolant discharge manifold MWO. It is explanatory drawing showing the amount distribution of the condensed water in a fuel cell, showing the relative position of each fuel cell in the fuel cell which has a stack structure on a horizontal axis. It is a side view of fuel cell 100A of the 2nd example. It is a side view of the fuel cell 100B of 3rd Example.

Explanation of symbols

10 ... MEA
DESCRIPTION OF SYMBOLS 22 ... Hydrogen supply part 24 ... Blower 40 ... Electrolyte membrane 41 ... Cathode 42 ... Anode 43 ... Gas diffusion layer 60 ... Hydrogen circulation pump 62 ... Groove 63 ... Groove 65 ... Gas-liquid separator 70 ... Refrigerant circulation pump 75 ... Refrigerant circulation flow Path 77 ... Radiators 81-86 ... Hole 87 ... Through hole 100, 100A, 100B ... Fuel cell 1000, 1000A, 1000B ... Fuel cell system TA ... Anode side terminal TC ... Cathode side terminal SL ... Fuel cell HS ... Heat insulation HT ... heater MAI ... oxidizing gas supply manifold TMA ... anode side terminal TMC ... cathode side terminal MAO ... oxidizing gas discharge manifold SPA ... separator MHI ... fuel gas supply manifold SPA ... anode side separator EPA ... anode side end plate SPC ... cathode side separator EPC ... Cathode side end plate ISA ... Anode side insulator ISC ... Cathode side insulator MHO ... Fuel gas discharge manifold MWI ... Refrigerant supply manifold MWO ... Refrigerant discharge manifold SPW ... Separator for refrigerant

Claims (4)

A fuel cell comprising an electrolyte membrane having an anode formed on one side and a cathode formed on the opposite side, and a plurality of fuel cells stacked such that the anode and the cathode are alternately arranged ,
At one end of the fuel cell, a first fuel cell provided with the anode toward the outside of the fuel cell is disposed, and at the other end of the fuel cell, the outside of the fuel cell. A second fuel cell provided with the cathode toward the surface is further disposed;
A plate-like member belonging to the one end of the fuel cell;
A refrigerant supply manifold for supplying a refrigerant for cooling the fuel cell to each fuel cell;
Refrigerant discharge manifold for collecting the refrigerant after cooling each fuel battery cell to flow in one direction and discharging it outside the fuel cell;
The fuel cell located in the vicinity of the one end of the fuel cell, wherein a cell average temperature of a plurality of fuel cells including the first fuel cell is calculated as the other end of the fuel cell. The fuel cell located in the vicinity, wherein the temperature riser is higher than the cell average temperature of a plurality of fuel cells including the second fuel cell,
With
The plate-like member has a refrigerant discharge passage serving as the temperature raising portion for flowing the refrigerant of the refrigerant discharge manifold in a direction along the plate surface of the plate-like member and discharging the refrigerant to the outside. A fuel cell. The fuel cell according to claim 1 , wherein
The fuel cell, wherein the plate-like member is an insulator. According to claim 1 or claim 2 Symbol mounting the fuel cell,
A fuel cell comprising a heater on the one end side of the fuel cell as the temperature raising portion. The fuel cell according to any one of claims 1 to 3 ,
A plate-like member belonging to the one end of the fuel cell;
The fuel cell according to claim 1, wherein a heat insulating material that covers at least one of the one end portion or the vicinity of the one end portion is provided as the temperature raising portion.

Images