JP2010123337A - Fuel cell system and apparatus for evaluating fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure humidity in a gas supplied to a fuel cell and/or in a gas exhausted from the fuel cell even if a condition varies when the fuel cell generates electricity. <P>SOLUTION: A fuel cell system provided with the fuel cell 15 includes: a humidity sensor that is arranged in a gas duct connected to the fuel cell 15; a section for adjusting a state containing water vapor, which is placed in an upper part of gas flow than the humidity sensor and adjusts a state of water content in the gas so that the water content in the gas exists as the water vapor in the duct; and a gas state adjustment section that adjusts the state of the gas relating to accuracy when the humidity is detected by the humidity sensor for the gas flowing from the section for adjusting the state containing water vapor to the humidity sensor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system and a fuel cell evaluation device.

  The electrolyte membrane included in the polymer electrolyte fuel cell exhibits high proton conductivity when in a wet state, and the proton conductivity decreases as the water content decreases. Therefore, in order to maintain the battery performance of the fuel cell, it is necessary to sufficiently maintain the water content of the electrolyte membrane. Therefore, when performing power generation using a fuel cell, it is important to manage the amount of water in the gas supplied to the fuel cell and / or the amount of water in the gas discharged from the fuel cell. Conventionally, as one configuration for managing the amount of water in the gas supplied to the fuel cell in this way, when the fuel gas is humidified and supplied to the fuel cell, the dew point temperature of the fuel gas is measured. Based on this, a fuel cell test apparatus that controls the humidification temperature when humidifying the fuel gas has been proposed (see, for example, Patent Document 1).

JP 2003-346855 A JP 2004-296233 A JP2007-192686A

  However, even when the humidity in the gas supplied to the fuel cell and / or the gas discharged from the fuel cell is measured in this way, the amount of water in the gas (the amount of water vapor and the amount of liquid water), the gas When the conditions such as the flow rate of the gas and the temperature of the gas fluctuate, the accuracy of measuring the gas humidity depends on the state of the liquid water in the gas and the nature of the measuring device for measuring the humidity such as a dew point meter. May be insufficient. Therefore, even when the fuel cell generates power and conditions that may affect the measurement of gas humidity vary, the humidity in the gas supplied to the fuel cell and / or the gas discharged from the fuel cell There is a need for a technique for accurately measuring the above.

  The present invention has been made in order to solve the above-described conventional problems, and even if the conditions under which the fuel cell generates power fluctuate, the gas supplied to the fuel cell and / or the fuel cell is discharged. The purpose is to accurately measure the humidity in the generated gas.

  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 system comprising a fuel cell,
A humidity sensor provided in a gas flow path connected to the fuel cell;
In the flow path, provided in the upstream of the flow of the gas from the humidity sensor, a water vapor containing state adjusting unit that adjusts the state of moisture in the gas so that the moisture in the gas exists as water vapor,
A fuel cell system comprising: a gas state adjusting unit that adjusts a state of the gas related to accuracy when the humidity is detected by the humidity sensor for the gas flowing from the water vapor containing state adjusting unit to the humidity sensor.

  In the fuel cell system described in Application Example 1, after the moisture state in the gas is adjusted by the steam-containing state adjustment unit so that the moisture in the gas flowing in the flow path connected to the fuel cell exists as water vapor. With respect to the gas, the gas state adjustment unit adjusts the state related to the accuracy when the humidity is detected by the humidity sensor, and the humidity of the gas is detected by the humidity sensor. Therefore, even when the conditions under which the fuel cell generates electricity fluctuate, it is possible to accurately measure the humidity in the gas whose moisture state has been adjusted so that the moisture in the gas exists as water vapor. Become.

[Application Example 2]
The fuel cell system according to Application Example 1, wherein the state adjusted by the gas state adjusting unit is a flow rate and / or a temperature of the gas supplied to the humidity sensor. According to the fuel cell system described in Application Example 2, by supplying the humidity sensor with the gas whose flow rate and / or temperature has been adjusted, the accuracy in detecting the humidity of the gas with the humidity sensor can be ensured.

[Application Example 3]
A fuel cell system according to Application Example 2,
The state adjusted by the gas state adjusting unit is the temperature of the gas, and the gas state adjusting unit is supplied with heat from the gas via the water vapor-containing state adjusting unit, and the temperature of the humidity sensor is A fuel cell system that is a heating unit that heats the gas so that the temperature is higher than a dew point temperature predicted for the gas and lower than an upper limit temperature allowed by the humidity sensor. According to the fuel cell system of Application Example 3, the gas state adjusting unit heats the gas that has passed through the water vapor-containing state adjusting unit, so that the temperature of the humidity sensor that receives heat supply from the gas is predicted in the gas. Higher than the dew point temperature. Therefore, condensation of water vapor in the gas can be suppressed in the humidity sensor, and a decrease in detection accuracy of the humidity sensor due to the condensed liquid water can be suppressed. Moreover, since the temperature of a humidity sensor becomes temperature lower than the upper limit temperature which a humidity sensor accept | permits, the fall of durability of a humidity sensor can be suppressed.

[Application Example 4]
The fuel cell system according to Application Example 3, wherein the heating unit includes a pipe heater that heats the gas by heating an entire pipe connecting the water vapor content state adjusting unit and the humidity sensor. system. According to the fuel cell system of Application Example 4, the heating unit that heats the gas heats the entire pipe connecting the water vapor content adjustment unit and the humidity sensor. In the adjusted gas, water vapor does not condense on the way, and the humidity of the gas maintaining the water vapor containing state adjusted by the water vapor containing state adjusting unit can be detected by the humidity sensor.

[Application Example 5]
5. The fuel cell system according to Application Example 3 or 4, wherein the flow path of the gas provided with the humidity sensor is a flow path through which the gas discharged from the fuel cell flows, and the fuel cell system further includes: , Based on the amount of water produced in the fuel cell, the assumed distribution of water in the fuel cell, the flow rate of gas supplied to the fuel cell, and the flow rate of gas consumed in the fuel cell, A dew point temperature predicting unit that predicts the dew point temperature of the gas flowing to the humidity sensor, and the heating unit is configured such that the temperature of the humidity sensor is higher than the dew point temperature predicted by the dew point temperature predicting unit. And a fuel cell system for heating the gas. According to the fuel cell system of Application Example 5, the temperature of the humidity sensor is higher than the gas dew point temperature in order to predict the dew point of gas discharged from the fuel cell according to specific conditions when the fuel cell generates power. Thus, the accuracy of the operation of heating the gas can be improved, and the reliability of the humidity detection operation in the humidity sensor can be improved.

[Application Example 6]
6. The fuel cell system according to any one of Application Examples 3 to 5, wherein the humidity sensor is a dew point meter that detects a dew point temperature of the gas, and the heating unit is in accordance with a dew point temperature detected by the dew point meter. A fuel cell system that changes the degree of heating of the gas. According to the fuel cell system described in Application Example 6, it is possible to accurately detect the dew point temperature of the gas even when the humidity in the gas varies by changing the degree of heating of the gas. .

[Application Example 7]
In the fuel cell system according to application example 6, when the dew point temperature detected by the dew point meter is lower than a lower limit temperature allowed by the dew point meter, the heating unit determines a difference between the dew point temperature and the lower limit temperature. Accordingly, a fuel cell system that reduces the degree of heating of the gas. According to the fuel cell system described in Application Example 7, when the detected dew point temperature is lower than the lower limit temperature, the amount of heating with respect to the gas is decreased according to the difference between the dew point temperature and the lower limit temperature, so the gas dew point temperature decreases. Even in this case, the dew point temperature can be accurately detected by the dew point meter.

[Application Example 8]
A fuel cell system according to Application Example 2,
The state adjusted by the gas state adjusting unit is a flow rate of the gas, and the gas state adjusting unit is provided in communication with the water vapor containing state adjusting unit, and the gas is adjusted without passing through the humidity sensor. The flow rate of the gas distributed to the humidity sensor and the bypass flow path is adjusted so that the flow rate of the gas supplied to the bypass flow path and the humidity sensor is less than or equal to the upper limit value allowed by the humidity sensor. A fuel cell system comprising a flow rate adjusting unit to be adjusted. According to the fuel cell system described in Application Example 8, even when the operating state of the fuel cell fluctuates and the flow rate of the gas passing through the water vapor containing state adjusting unit fluctuates, the gas supplied to the humidity sensor Since the flow velocity is suppressed to the upper limit value or less, it is possible to suppress a decrease in detection accuracy in the humidity sensor and to measure the gas humidity with high accuracy.

[Application Example 9]
The fuel cell system according to any one of Application Examples 1 to 8, wherein the gas flow path provided with the humidity sensor is a flow path through which gas discharged from the fuel cell flows, and the water vapor content adjustment The fuel cell system is a vaporizer that heats the gas discharged from the fuel cell and vaporizes the entire amount of liquid water present in the gas. According to the fuel cell system described in Application Example 9, since the entire amount of liquid water present in the gas is vaporized by the vaporizer, all the moisture in the gas is changed to water vapor, and the total amount of moisture in the gas is reduced. It becomes possible to measure with high accuracy using a humidity sensor. Further, since the humidity sensor is supplied with a gas in which the entire amount of liquid water is vaporized, the amount of moisture in the gas can be accurately detected with good time resolution.

[Application Example 10]
9. The fuel cell system according to any one of Application Examples 1 to 4, and 8, wherein the gas flow path provided with the humidity sensor is a flow path through which a gas supplied to the fuel cell flows. The water vapor-containing state adjusting unit is a fuel cell system that is a humidifier that humidifies the gas supplied to the fuel cell. According to the fuel cell system of Application Example 10, the amount of water vapor in the gas humidified by the humidifier and supplied to the fuel cell can be accurately measured using the humidity sensor.

[Application Example 11]
The fuel cell system according to any one of Application Examples 1 to 10, further comprising a fuel cell evaluation unit for evaluating the behavior of water in the fuel cell based on a detection value of the humidity sensor. According to the fuel cell system described in the application example 11, the humidity in the gas supplied to the fuel cell and / or the gas discharged from the fuel cell can be accurately detected by the humidity sensor. The behavior of can be evaluated with higher accuracy.

  The present invention can be realized in various forms other than those described above. For example, the fuel cell system of the present invention can be realized in the form of an apparatus that is used as a fuel cell evaluation apparatus.

A. Overall configuration of the device:
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell evaluation apparatus 10 as a preferred embodiment of the present invention, in which a fuel cell 15 to be evaluated is attached and operated as a fuel cell system as a whole. It is. The fuel cell evaluation device 10 includes a fuel gas supply unit 20, a fuel gas supply channel 60, a fuel gas discharge channel 62, an oxidizing gas supply unit 30, an oxidizing gas supply channel 64, an oxidizing gas discharge channel 66, and a control. Part 70.

  The fuel gas supply unit 20 is a device for supplying a fuel gas containing hydrogen to the anode of the fuel cell 15. In this embodiment, the fuel gas supply unit 20 is constituted by a hydrogen tank that stores hydrogen.

  The fuel gas supply channel 60 is a channel that connects the fuel gas supply unit 20 and the fuel cell 15. The fuel gas supply path 60 is provided with the first mass flow meter 21, and the flow rate of the fuel gas supplied to the fuel cell 15 is adjusted by the first mass flow meter 21 in the state of the dry gas before humidification. In the fuel gas supply path 60, a first humidifier 22 is provided on the downstream side of the first mass flow meter 21. In the present embodiment, the first humidifier 22 is constituted by a bubbler, and the humidification amount for the fuel gas can be controlled by adjusting the temperature of the bubbler. Here, as a flow path for introducing the fuel gas into the bubbler that is the first humidifier 22, the first humidified gas branch that branches from the fuel gas supply path 60, passes through the bubbler, and merges with the fuel gas supply path 60 again. A path 80 is provided. A three-way valve 68 is provided at the connection between the fuel gas supply path 60 and the first humidified gas branch path 80. By switching the three-way valve 68, it is possible to make the fuel gas unhumidified.

  In the fuel gas supply path 60, a first dew point meter 24, a first pressure gauge 25, and a first flow meter 26 are provided on the downstream side of the first humidifier 22. By the first dew point meter 24, the first pressure gauge 25, and the first flow meter 26, the dew point temperature, pressure, and flow rate of the humidified fuel gas flowing through the fuel gas supply path 60 are detected. In this embodiment, a specular dew point meter is used as the first dew point meter 24. In addition to the specular dew point meter, it is possible to detect the humidity of the fuel gas by using various humidity sensors such as a polymer capacitive humidity sensor and a laser dew point meter. The reliability with respect to accuracy is particularly high (for example, the error is about ± 0.2 ° C.), which is desirable. The humidity sensor used can accurately detect the water vapor partial pressure even when the conditions relating to the power generation of the fuel cell 15 fluctuate and the water vapor partial pressure in the fuel gas fluctuates, and the water vapor content can be detected with good time resolution. It is sufficient if the pressure can be detected.

  Here, the first dew point meter 24 is provided with a first dew point meter heater 82. The first dew point heater 82 is for heating the fuel gas whose dew point temperature is measured by the first dew point meter 24. In this way, by heating the fuel gas by the first dew point meter heater 82, Condensation of water vapor in the fuel gas in the vicinity of the first dew point meter 24 is suppressed. The control of the heating amount of the fuel gas by the first dew point heater 82 will be described in detail later. The first dew point meter 24 is also provided with a first temperature sensor 83. The first temperature sensor 83 detects the temperature of the fuel gas that is heated by the first dew point meter heater 82 and whose dew point temperature is measured by the first dew point meter 24.

  In the fuel gas supply path 60, a first pipe heater 23 is provided between the first humidifier 22 and the first dew point meter 24. In the present embodiment, the first pipe heater 23 is a pipe that connects the first humidifier 22 and the first dew point meter 24 (in the first humidified gas branch 80, the fuel gas that has passed through the first humidifier 22 flows). And in the fuel gas supply path 60, the fuel gas flows through the first humidified gas branch path 80), and the fuel gas is heated to a desired temperature by energization. More specifically, the 1st piping heater 23 is formed by coat | covering the said piping using the ribbon-shaped heater which has arrange | positioned the heat-transfer coil inside, and also coat | covering the outer side with a heat insulating material. In the present embodiment, the first heating unit is formed by the first pipe heater 23 and the first dew point meter heater 82 described above. The first heating unit is configured such that the temperature of the first dew point meter 24 to which the heated fuel gas is supplied is higher than the predicted dew point temperature of the fuel gas and lower than the heat resistant temperature of the first dew point meter 24. The fuel gas is heated so that The manner of heating in the first heating unit will be described in detail later.

  Further, the fuel gas supply path 60 branches from the fuel gas supply path 60 in the middle of the portion where the first pipe heater 23 is provided, and the first dew point meter 24, the first pressure gauge 25, and the first flow meter 26 are connected. A supply fuel gas bypass passage 61 that guides the fuel gas further downstream of the fuel gas supply passage 60 is provided without passing through the fuel gas supply passage 60. A first flow rate adjustment valve 27 is provided in the supply fuel gas bypass passage 61. By providing such a supply fuel gas bypass passage 61, part of the fuel gas humidified by the first humidifier 22 flows through the supply fuel gas bypass passage 61, and the first dew point meter 24, the first pressure gauge 25, and The fuel gas flow rate via the first flow meter 26 is suppressed. The configuration in which the fuel gas flow rate via the first dew point meter 24 and the like is suppressed by the supply fuel gas bypass passage 61 will be described in detail later.

  In the fuel gas supply path 60, a second pressure gauge 28 is provided downstream of the first flow meter 26 and downstream of the junction with the supply fuel gas bypass path 61. The pressure of the fuel gas flowing into the fuel cell 15 is detected by the second pressure gauge 28. Further, in the fuel gas supply path 60, the vicinity of the connection with the fuel cell 15 (in FIG. 1, between the second pressure gauge 28 and the connection between the fuel gas supply path 60 and the fuel cell 15) is the first. A temperature adjustment unit 29 is provided. In the present embodiment, the first temperature adjusting unit 29 is configured by a temperature adjusting fluid channel provided so as to cover a pipe connecting the second pressure gauge 28 and the fuel cell 15. The temperature of the fuel gas supplied to the fuel cell 15 can be set to a desired temperature by flowing a temperature adjusting fluid controlled to a predetermined temperature through the flow path provided in the first temperature adjusting unit 29.

  The fuel gas discharge path 62 is a flow path that is connected to the fuel cell 15 and through which discharged fuel gas discharged via the anode of the fuel cell 15 flows. In the fuel gas discharge path 62, a third pressure gauge 31 is provided in the vicinity of the connection portion with the fuel cell 15, and the pressure of the discharged fuel gas discharged from the fuel cell 15 is reduced by the third pressure gauge 31. Detected. Further, a first carburetor 32 is provided in the fuel gas discharge path 62 on the downstream side of the third pressure gauge 31. The first vaporizer 32 according to the present embodiment includes a heater provided so as to cover a part of the pipe constituting the fuel gas discharge path 62, similarly to the first pipe heater 23 described above. However, in the first vaporizer 32, the exhaust fuel gas is heated at a temperature higher than that of the first pipe heater 23. When a fuel cell generates electricity, water is generated with the generation of electricity, and the gas discharged from the fuel cell contains a lot of water vapor. In this embodiment, the first vaporizer 32 is provided to vaporize all the liquid water in the fuel gas discharge passage 62. Therefore, the set temperature in the first carburetor 32 is the maximum amount that the power generation amount in the fuel cell 15 is assumed, and even if the amount of generated water is maximum, all the water in the fuel gas discharge path 62 is discharged. It is set as a temperature that can be converted to water vapor. Specifically, the set temperature in the first vaporizer 32 can be set to a constant temperature in the range of 100 to 220 ° C., for example. In this embodiment, the set temperature of the first vaporizer 32 is 200 ° C. Note that the set temperature of the first carburetor 32 can be changed according to the flow rate of the exhaust fuel gas supplied to the first carburetor 32 and the power generation amount (generated water amount) generated in the fuel cell 15.

  In the fuel gas discharge path 62, a second dew point meter 34, a fourth pressure gauge 35, and a second flow meter 36 are provided on the downstream side of the first vaporizer 32. The second dew point meter 34 has the same configuration as the first dew point meter 24. By these second dew point meter 34, fourth pressure gauge 35, and second flow meter 36, the dew point temperature, pressure, and flow rate of the exhaust fuel gas flowing through the fuel gas discharge path 62 are detected. Here, the second dew point meter 34 is provided with a second dew point meter heater 84 and a second temperature sensor 85 similar to the first dew point meter heater 82 and the first temperature sensor 83 in the first dew point meter 24. . The fuel gas whose dew point temperature is measured by the second dew point meter 34 is heated by the second dew point meter heater 84, and the temperature of the heated fuel gas is detected by the second temperature sensor 85. In such a fuel gas discharge path 62, a second pipe heater 33 is provided between the first vaporizer 32 and the second dew point meter 34. The second pipe heater 33 has the same configuration as the first pipe heater 23 provided in the fuel gas supply path 60, and forms a second heating unit together with the second dew point meter heater 84. In the second heating unit, the temperature of the second dew point meter 34 to which the exhaust fuel gas heated by the second heating unit is supplied is higher than the dew point temperature predicted for the exhaust fuel gas, and the heat resistant temperature in the second dew point meter 34 The exhaust fuel gas is heated so that the temperature becomes lower than that. The manner of heating in the second heating unit will be described in detail later.

  In addition, the fuel gas discharge passage 62 branches from the fuel gas discharge passage 62 to the downstream side of the fuel gas discharge passage 62 without passing through the second dew point meter 34, the fourth pressure gauge 35, and the second flow meter 36. A fuel gas bypass 63 is provided. The exhaust fuel gas bypass passage 63 is provided with a second flow rate adjustment valve 37. By providing such an exhaust fuel gas bypass passage 63, part of the exhaust fuel gas that has been vaporized of the liquid water in the first vaporizer 32 flows through the exhaust fuel gas bypass passage 63, and the second dew point meter 34, The flow rate of the exhaust fuel gas passing through the fourth pressure gauge 35 and the second flow meter 36 is suppressed. The configuration in which the exhaust fuel gas flow rate passing through the second dew point meter 34 and the like is suppressed by the exhaust fuel gas bypass passage 63 will be described in detail later.

  In the fuel gas discharge path 62, a first back pressure valve 38 is provided downstream of the second flow meter 36 and downstream of the junction with the exhaust fuel gas bypass path 63. In this embodiment, the pressure of the fuel gas in the fuel cell 15 is adjusted by adjusting the opening degree of the first back pressure valve 38 based on the detection signal of the third pressure gauge 31.

  The oxidizing gas supply unit 30 is an apparatus for supplying an oxidizing gas containing oxygen to the cathode side of the fuel cell 15. The oxidizing gas supply unit 30 can be configured by, for example, a blower that takes in air and compresses it.

  The oxidizing gas supply path 64 is a flow path for connecting the oxidizing gas supply unit 40 and the fuel cell 15. A second mass flow meter 41 is provided in the oxidizing gas supply path 64, and the flow rate of the oxidizing gas supplied to the fuel cell 15 is adjusted by the second mass flow meter 41 in a dry gas state before humidification. Further, in the oxidizing gas supply path 64, on the downstream side of the second mass flow meter 41, a second humidifier 42 similar to the first humidifier 22 in the fuel gas supply path 60 includes a three-way valve 69 and a second humidified gas branch path. 81 is provided.

  In the oxidizing gas supply path 64, a third dew point meter 44, a fifth pressure gauge 45, and a third flow meter 46, which are the same as the sensors provided in the fuel gas supply path 60, are located downstream of the second humidifier 42. Is provided. The third dew point meter 44, the fifth pressure gauge 45, and the third flow meter 46 detect the dew point temperature, pressure, and flow rate of the humidified oxidizing gas that flows through the oxidizing gas supply path 64, respectively. Here, the third dew point meter 44 is provided with a third dew point meter heater 86 and a third temperature sensor 87 similar to the first dew point meter heater 82 and the first temperature sensor 83 in the first dew point meter 24. . The oxidizing gas whose dew point temperature is measured by the third dew point meter 44 is heated by the third dew point meter heater 86, and the temperature of the heated oxidizing gas is detected by the third temperature sensor 87. In such an oxidizing gas supply path 64, a third pipe heater 43 similar to the first pipe heater 23 is provided between the second humidifier 42 and the third dew point meter 44. The third piping heater 43 forms a third heating unit together with the third dew point meter heater 86. The third heating unit is configured such that the temperature of the third dew point meter 44 to which the oxidizing gas heated by the third heating unit is supplied is higher than the predicted dew point temperature of the supplied oxidizing gas, and is higher than the heat resistant temperature in the third dew point meter 44. The oxidizing gas is heated so that the temperature becomes lower. The manner of heating in the third heating unit will be described in detail later.

  Further, the supply oxidation that branches from the oxidizing gas supply path 64 and guides the oxidizing gas downstream of the oxidizing gas supply path 64 without passing through the third dew point meter 44, the fifth pressure gauge 45, and the third flow meter 46. A gas bypass 65 is provided. The supply oxidant gas bypass 65 is provided with a third flow rate adjustment valve 47 similar to the first flow rate adjustment valve 27, and a third dew point meter 44, a fifth pressure gauge 45, and a third flow meter 46 are provided. The oxidizing gas flow rate in the provided oxidizing gas supply path 64 is suppressed. The configuration in which the supply oxidant gas flow rate via the third dew point meter 44 and the like is suppressed by the supply oxidant gas bypass 65 will be described in detail later.

  Further, a sixth pressure gauge 48 is provided in the oxidizing gas supply path 64 downstream of the junction with the supply oxidizing gas bypass path 65, and flows into the fuel cell 15 by the sixth pressure gauge 48. The pressure of the oxidizing gas is detected. Further, in the oxidizing gas supply path 64, a second temperature adjusting unit 49 similar to the first temperature adjusting unit 29 is provided in the vicinity of the connection part with the fuel cell 15, and by this second temperature adjusting unit 49, The oxidizing gas temperature supplied to the fuel cell 15 is adjusted to a desired temperature.

  The oxidizing gas discharge path 66 is a flow path that is connected to the fuel cell 15 and into which discharged oxidizing gas discharged via the cathode of the fuel cell 15 is introduced. A seventh pressure gauge 51 is provided in the oxidizing gas discharge path 66, and the pressure of the discharged oxidizing gas discharged from the fuel cell 15 is detected by the seventh pressure gauge 51. Furthermore, a second vaporizer 52 similar to the first vaporizer 32 is provided in the oxidizing gas discharge path 66 on the downstream side of the seventh pressure gauge 51, and the second vaporizer 52 allows the oxidizing gas to flow. All liquid water in the discharge channel 66 is vaporized.

  In the oxidizing gas discharge channel 66, a fourth dew point meter 54, an eighth pressure gauge 55, and a fourth flow meter 56 are provided downstream of the second vaporizer 52. By the fourth dew point meter 54, the eighth pressure gauge 55, and the fourth flow meter 56, the dew point temperature, pressure, and flow rate of the exhausted oxidant gas flowing through the oxidant gas discharge path 66 are detected. Here, the fourth dew point meter 54 is provided with a fourth dew point meter heater 88 and a fourth temperature sensor 89 similar to the first dew point meter heater 82 and the first temperature sensor 83 in the first dew point meter 24. . The oxidizing gas whose dew point temperature is measured by the fourth dew point meter 54 is heated by the fourth dew point meter heater 88, and the temperature of the heated oxidizing gas is detected by the fourth temperature sensor 89. In such an oxidizing gas discharge path 66, a fourth pipe heater 53 similar to the first pipe heater 23 is provided between the second vaporizer 52 and the fourth dew point meter 54. The fourth pipe heater 53 and the fourth dew point meter heater 88 form a fourth heating unit. The fourth heating unit is configured such that the temperature of the fourth dew point meter 54 to which the exhausted oxidant gas heated by the fourth heating unit is supplied is higher than the predicted dew point temperature in the exhausted oxidant gas, and the heat resistant temperature in the fourth dew point meter 54. The exhaust oxidant gas is heated so that the temperature becomes lower than that. The manner of heating in the fourth heating unit will be described in detail later.

  Further, the exhaust gas is branched from the oxidant gas discharge path 66 and led to the downstream side of the oxidant gas discharge path 66 without passing through the fourth dew point meter 54, the eighth pressure gauge 55, and the fourth flow meter 56. An oxidizing gas bypass 67 is provided. The exhaust oxidant gas bypass passage 67 is provided with a fourth flow rate adjustment valve 57 similar to the first flow rate adjustment valve 27, and a fourth dew point meter 54, an eighth pressure gauge 55, and a fourth flow meter 56 are provided. The flow rate of exhaust oxidant gas in the provided oxidant gas exhaust path 66 is suppressed. The configuration in which the exhaust oxidant gas flow rate via the fourth dew point meter 54 and the like is suppressed by the exhaust oxidant gas bypass passage 67 will be described in detail later.

  In the oxidizing gas discharge path 66, a second back pressure valve 58 is provided downstream of the fourth flow meter 56 and downstream of the junction with the exhaust oxidizing gas bypass path 67. In this embodiment, the pressure of the oxidizing gas in the fuel cell 15 is adjusted by adjusting the opening degree of the second back pressure valve 58 based on the detection signal of the seventh pressure gauge 51.

  The control unit 70 is configured as a logic circuit centered on a microcomputer, and includes a CPU, a ROM, a RAM, an input / output port for inputting and outputting various signals, and the like. This controller 70 includes dew point meters 24, 34, 44, 54, pressure gauges 25, 28, 31, 35, 45, 48, 51, 55, flow meters 26, 36, 46, 56, temperature sensors 83, 85, 87, 89 output signals, information on the fuel cell 15 to be evaluated (for example, a detection signal from a temperature sensor (not shown) that detects the operating temperature of the fuel cell 15 and the output of the fuel cell 15 as the amount of power generation). A detection signal from a current sensor (not shown) that detects a current value), and outputs a drive signal to each part related to adjustment of the operating conditions of the fuel cell 15, such as the mass flow meters 21 and 41 and the back pressure valves 38 and 58. To do. Moreover, a drive signal is output to each heating part etc., and the conditions at the time of dew point meter 24,34,44,54 grade | etc., Detecting are adjusted. Such a control unit 70 controls the movement of each part of the fuel cell evaluation device 10 and the fuel cell 15, and also serves as an evaluation unit that evaluates the behavior of water in the fuel cell 15 corresponding to the operating conditions in the fuel cell 15. Function.

  The fuel cell 15 to be evaluated by the fuel cell evaluation apparatus 10 is typically a polymer electrolyte fuel cell, but can be applied to other forms of fuel cells such as a solid oxide fuel cell. The fuel cell 15 has a stack structure in which a plurality of single cells that are units of power generation are stacked. Inside the fuel cell 15, there are provided a plurality of manifolds that are provided in parallel to the stacking direction of the single cells and supply and discharge gas to and from the gas flow paths in each single cell. Specifically, a fuel gas supply manifold that distributes the fuel gas to the fuel gas flow path in each single cell, a fuel gas discharge manifold that collects the fuel gas discharged from the fuel gas flow path in each single cell, An oxidizing gas supply manifold that distributes the oxidizing gas to the oxidizing gas flow path in each single cell, and an oxidizing gas discharge manifold that collects the oxidizing gas discharged from the oxidizing gas flow path in each single cell are provided. .

  When the fuel cell 15 is evaluated using the fuel cell evaluation device 10, the gas flow path provided in the fuel cell evaluation device 10 and the gas manifold provided in the fuel cell 15 to be evaluated are connected. That is, between the fuel gas supply path 60 and the fuel gas supply manifold, between the fuel gas discharge path 62 and the fuel gas discharge manifold, between the oxidant gas supply path 64 and the oxidant gas supply manifold, and between the oxidant gas discharge path 66 and The oxidant gas discharge manifold is connected to each other.

B. Operations related to heating of supply gas:
As described above, in the present embodiment, the temperature of the first dew point meter 24 through which the supply fuel gas heated by the first heating unit flows is higher than the predicted dew point temperature in the supply fuel gas. The amount of heating of the first heating unit is controlled by the control unit 70 so that the temperature is lower than the heat-resistant temperature at. In addition, the temperature of the third dew point meter 44 through which the supply oxidizing gas heated by the third heating unit flows is higher than the predicted dew point temperature in the supply oxidizing gas and lower than the heat resistant temperature in the third dew point meter 44. As described above, the control unit 70 controls the heating amount of the third heating unit. Below, the operation | movement of the heating in such a heating part is demonstrated. In the following, the operation of the first heating unit for heating the fuel gas supplied to the fuel cell 15 will be described, but the operation in the third heating unit for heating the oxidizing gas is the same.

  Here, when all the fuel gas is guided to the first humidifier 22 for humidification, the temperature of the fuel gas discharged from the first humidifier 22 to the first heating unit side and the dew point temperature in this fuel gas. Is substantially equal to the set temperature of the bubbler constituting the first humidifier 22. Therefore, in this embodiment, the set temperature of the bubbler is the predicted dew point temperature of the fuel gas discharged from the first humidifier 22. Here, in the first dew point meter 24 that receives supply of heat from the fuel gas heated by the first heating unit, the dew point temperature is accurately obtained without condensing water vapor in the fuel gas supplied to the first dew point meter 24. Is detected as a target temperature that is higher than the predicted dew point temperature (bubbler temperature) in the fuel gas. Specifically, for example, a temperature that is 5 to 25 ° C. higher than the set temperature in the bubbler and lower than the heat-resistant temperature in the first dew point meter 24 may be set as the target temperature of the first dew point meter 24. In this embodiment, the target temperature of the first dew point meter 24 is set to a temperature 20 ° C. higher than the set temperature in the bubbler. In the first heating unit, the heating amount for the fuel gas is controlled so that the first dew point meter 24 can be set to the above-described target temperature by the heat of the fuel gas heated in the first heating unit.

  The first dew point meter 24 is heated by the fuel gas supplied to the first dew point meter 24, and the fuel gas supplied to the first dew point meter 24 is a first dew point meter provided in the first dew point meter 24. Heated by the meter heater 82 and the first piping heater 23. In the present embodiment, the heating amount by the first piping heater 23 is constant, and the temperature of the first dew point meter 24 increases as the heating amount by the first dew point meter heater 82 increases. At this time, the amount of heat given from the fuel gas to the first dew point meter 24 increases as the fuel gas flow rate increases, and as the heater control temperature (heating amount for the fuel gas) in the first dew point meter heater 82 increases. The higher the temperature (fuel gas temperature before heating), the higher. FIG. 2 is an explanatory diagram showing the relationship between the fuel gas flow rate (dry gas flow rate in the first mass flow meter 21) and the heater control temperature in the first dew point meter heater 82 when the bubbler temperature is set to a predetermined temperature. . Thus, by setting the dew point meter heater control temperature to be lower as the gas flow rate is larger, the temperature of the first dew point meter 24 heated by the fuel gas can be set to the target temperature described above. In this embodiment, the relationship between the fuel gas flow rate and the dew point heater control temperature is stored in advance in the control unit 70 as a map for each bubbler temperature, and the control unit 70 stores the bubbler temperature and the dry gas flow rate. By referring to the map based on the above, the heater control temperature in the first dew point meter heater 82 is determined, and the energization amount to the first dew point meter heater 82 is controlled. However, in practice, it is not realistic to store a huge map for each bubbler temperature, so in this example, a map is prepared for each set range by dividing the bubbler temperature into a certain range. ing. In such a map, even when the bubbler temperature fluctuates within the set range and other conditions related to power generation of the fuel cell 15 fluctuate, the temperature of the first dew point meter 24 is higher than the dew point temperature. It may be set so that the temperature can be kept higher than the heat resistance temperature of the first dew point meter 24. Here, the heating amount by the first pipe heater 23 is a constant amount set so that liquid water does not condense in the pipe, and the first dew point meter is heated by the heating of the fuel gas by the first dew point meter heater 82. Since the temperature of 24 is raised to a desired temperature, the control temperature in the first dew point meter heater 82 is higher than the target temperature of the first dew point meter 24.

  In addition, the 1st piping heater 23 is provided covering the whole flow path which connects the 1st humidifier 22 and the 1st dew point meter 24 as mentioned above. As described above, since the fuel gas is heated in the entire flow path connecting the first humidifier 22 and the first dew point meter 24, the water vapor in the fuel gas is not condensed in the flow path, and the first humidification is performed. The dew point temperature of the fuel gas can be measured by the first dew point meter 24 in a state where the amount of water vapor applied by the vessel 22 is maintained.

C. Operations related to exhaust gas heating:
As described above, in the present embodiment, the temperature of the second dew point meter 34 to which the exhaust fuel gas heated by the second heating unit is supplied is higher than the dew point temperature predicted for the exhaust fuel gas, and the second dew point. The control unit 70 controls the heating amount of the second heating unit so that the temperature is lower than the heat-resistant temperature in the total 34. Further, the temperature of the fourth dew point meter 54 to which the exhaust oxidant gas heated by the fourth heating unit is supplied is higher than the predicted dew point temperature in the exhaust oxidant gas and lower than the heat resistant temperature in the fourth dew point meter 54. Then, the control unit 70 controls the heating amount of the fourth heating unit. Below, the operation | movement of the heating in such a heating part is demonstrated. In the following, the operation of the second heating unit that heats the exhaust fuel gas will be described, but the operation in the fourth heating unit that heats the exhaust oxidation gas is also the same.

  Here, the amount of water vapor in the exhausted fuel gas is the amount of water vapor added in the fuel cell 15 to the amount of water vapor in the fuel gas supplied to the fuel cell 15 (the amount of generated water moved from the cathode side through the electrolyte membrane). ) Is added. Further, the flow rate of the exhaust fuel gas is obtained by subtracting the amount of hydrogen consumed for power generation in the fuel cell 15 from the flow rate of the fuel gas supplied to the fuel cell 15 and adding the amount of water vapor added in the fuel cell 15. Value. The dew point temperature in the exhaust fuel gas is affected by the amount of water vapor in the exhaust fuel gas and the flow rate of the exhaust fuel gas. As described above, the amount of water vapor in the exhaust fuel gas and the flow rate of the exhaust fuel gas are determined by the fuel cell 15. It varies depending on various conditions when generating electricity. Therefore, when the target temperature in the second dew point meter 34 is determined so that the temperature of the second dew point meter 34 heated by the exhaust fuel gas is higher than the predicted dew point temperature of the exhaust fuel gas, Based on the power generation conditions in the battery 15, the dew point temperature in the exhausted fuel gas is predicted. The target temperature in the second dew point meter 34 may be a temperature that is 5 to 25 ° C. higher than the predicted dew point temperature of the exhaust fuel gas and lower than the heat-resistant temperature in the second dew point meter 34. In this embodiment, the target temperature of the second dew point meter 34 is 20 ° C. higher than the predicted dew point temperature of the exhaust fuel gas. In the second heating unit, the amount of heat with respect to the exhaust fuel gas is controlled so that the second dew point meter 34 can be set to the target temperature described above by the heat of the exhaust fuel gas heated in the second heating unit. It is.

  The prediction of the exhaust gas dew point temperature will be further described. FIG. 3 is an explanatory diagram collectively showing the relationship between the flow rate and the pressure for each of the fuel gas and the oxidizing gas supplied to and discharged from the fuel cell 15. The total gas flow rate is represented as Qtotal, the water vapor amount as Qvapor, the dry gas flow rate as Qdry, the total gas pressure as Ptotal, and the water vapor partial pressure as Pvapor. Also, in each value related to flow rate or pressure, the number 1 is assigned to the supplied fuel gas, the number 2 is assigned to the exhausted fuel gas, the number 3 is assigned to the supplied oxidizing gas, and the number is assigned to the exhausted oxidizing gas. 4 is attached. The dew point temperature in the exhaust fuel gas can be obtained from the water vapor partial pressure (Pvapor2) in the exhaust fuel gas and the pressure of the exhaust fuel gas. In this way, the water vapor partial pressure (Pvapor2) in the exhaust fuel gas used to predict the dew point temperature is the flow rate of the exhaust fuel gas (Qtotal2), the amount of water vapor in the exhaust fuel gas (Qvapor2), and the total amount of exhaust fuel gas. Using the pressure (Pvapor2), it is determined by the following equation (1).

  Pvapor2 = Ptotal2 × Qvaper2 / Qtotal2 (1)

  Here, the pressure detected by the third pressure gauge 31 may be used as the total pressure (Ptotal2) of the discharged fuel gas in the equation (1). In addition, the amount of water vapor (Qvapor2) in the discharged fuel gas in the equation (1) is equal to the amount of water vapor (Qvapor1) in the supplied fuel gas supplied to the fuel cell 15 and the fuel in the fuel cell 15 as described above. It is the sum of the amount of water vapor (Qadd1) added to the gas and can be determined by the following equation (2).

  Qvapor2 = Qvapor1 + Qadd1 (2)

  The amount of water vapor (Qvapor1) in the supplied fuel gas in the equation (2) is the water vapor partial pressure (Pvapor1) in the supplied fuel gas, the total pressure (Ptotal1) of the supplied fuel gas detected by the second pressure gauge 28, Based on the dry gas flow rate (Qdry1) of the supplied fuel gas in the one mass flow meter 21, it can be obtained by the following equation (3). Here, the water vapor partial pressure in the gas is a value that can be obtained based on the dew point temperature and gas pressure of the gas, and the control unit 70 detects the dew point temperature detected by the first dew point meter 24 and the first pressure gauge. The pressure in the first dew point meter 24 detected by 25 is acquired, and the water vapor partial pressure (Pvapor1) in the supplied fuel gas is derived.

  Qvapor1 = Qdry1 × Pvapor1 / (Ptotal1-Pvapor1) (3)

  Further, the amount of water vapor (Qadd1) added to the fuel gas in the fuel cell 15 in the equation (2) is obtained based on the amount of water generated in the fuel cell 15 and the distribution ratio of water in the fuel cell 15. Can do. That is, of the generated water generated in the fuel cell 15, the amount of generated water distributed from the cathode side to the anode side at a predetermined ratio is the amount of water vapor (Qadd1) added to the fuel gas in the fuel cell 15 It becomes. Here, the amount of water generated in the fuel cell 15 can be calculated based on the amount of power generation (current density) in the fuel cell 15. The amount of power generation in the fuel cell 15 may be acquired as the magnitude of the load request in the load connected to the fuel cell 15, or may be acquired by detecting the output current of the fuel cell 15 with an ammeter (not shown). good. Further, the water distribution ratio in the fuel cell 15 may be determined in advance and stored in the control unit 70, for example. The distribution ratio determined and stored in advance can be obtained, for example, by conducting a preliminary experiment in advance. Alternatively, when the evaluation using the fuel cell evaluation device 10 is performed, an arbitrary numerical value may be input by the user. As will be described later, the fuel cell evaluation apparatus 10 of the present embodiment actually measures the amount of water in the supply gas and the amount of water in the exhaust gas, so that the operating conditions of the fuel cell and the membrane of the fuel cell are measured. -An apparatus for evaluating the relationship between the behavior of water in the electrode assembly (MEA) and determining the water distribution ratio in the course of the evaluation. Therefore, in the processing based on the above equation (3), the distribution ratio of water used to obtain the amount of water vapor (Qadd1) added to the fuel gas in the fuel cell 15 is obtained using the value obtained with the evaluation. Correction may be performed.

  Returning to the equation (1), the flow rate (Qtotal2) of the discharged fuel gas in the equation (1) is further provided with a flow meter, for example, in the vicinity of the third pressure gauge 31 in the fuel gas discharge passage 62, ) May be actually measured. Alternatively, using the supplied fuel gas flow rate (Qtotal1), the amount of hydrogen consumed in the fuel cell 15 (QconH), and the amount of water vapor added to the fuel gas in the fuel cell 15 (Qadd1), You may calculate by.

  Qtotal2 = Qtotal1-QconH + Qadd1 (4)

  In the equation (4), the supply fuel gas flow rate (Qtotal1) is the dry gas flow rate (Qdry1) of the supply fuel gas in the first mass flow meter 21, as described in the following equation (5). It can be determined as the sum of the amount of water vapor (Qvapor1) in the supplied fuel gas determined based on the equation. In equation (4), the amount of hydrogen consumed (QconH) in the fuel cell 15 can be obtained based on the amount of power generation (current density) in the fuel cell 15. In the equation (4), the amount of water vapor (Qadd1) added to the fuel gas in the fuel cell 15 is the amount of water produced in the fuel cell 15 and the distribution of water in the fuel cell 15 as described above. It can be determined based on the ratio.

  Qtotal1 = Qdry1 + Qvapor1 (5)

  In the present embodiment, the partial pressure of water vapor (Pvapor2) in the exhausted fuel gas thus obtained based on the formula (1) and the pressure detected by the third pressure gauge 45 (exhaust fuel gas in the second dew point meter 34). The dew point temperature in the second dew point meter 34 is predicted based on the And the temperature 20 degreeC higher than the dew point temperature in the 2nd dew point meter 34 estimated in this way is made into the target temperature of the 2nd dew point meter 34 heated by exhaust fuel gas.

  The second dew point meter 34 is heated by the exhaust fuel gas supplied to the second dew point meter 34, and the exhaust fuel gas supplied to the second dew point meter 34 is attached to the second dew point meter 34. Heated by the two dew point meter heater 84 and the second pipe heater 33. In this embodiment, the heating amount by the second pipe heater 33 is constant, and the temperature of the second dew point meter 34 increases as the heating amount by the second dew point meter heater 84 increases. At this time, the amount of heat given from the exhaust fuel gas to the second dew point meter 34 increases as the exhaust fuel gas flow rate increases, and as the heater control temperature (heating amount for the exhaust fuel gas) in the second dew point meter heater 84 increases. Become more. FIG. 4 is an explanatory diagram showing the relationship between the exhaust fuel gas flow rate (Qtotal 2) and the heater control temperature in the second dew point meter heater 84. As described above, the exhaust fuel gas flow rate (Qtotal2) may be an actual measurement value or a theoretically calculated value. Thus, by setting the dew point meter heater control temperature to be lower as the gas flow rate is higher, the temperature in the second dew point meter 34 can be set to a predetermined target temperature. In the present embodiment, such a relationship between the exhaust fuel gas flow rate and the dew point meter heater control temperature is stored in advance in the control unit 70 as a map for each predicted dew point temperature, and based on the exhaust fuel gas flow rate. By referring to the map, the heater control temperature in the second dew point meter heater 84 is determined, and the energization amount to the second dew point meter heater 84 is controlled. However, since it is not practical to store an enormous map for each predicted dew point temperature, in this embodiment, the predicted dew point temperature is divided into a certain range and set ranges. A map is prepared for each. In such a map, even if the dew point temperature fluctuates within a set range and other conditions related to power generation of the fuel cell 15 fluctuate, the temperature of the second dew point meter 34 is higher than the dew point temperature. Is set so that it can be maintained at a higher temperature than the heat resistance temperature of the second dew point meter 34. Here, the heating amount by the second pipe heater 33 is a constant amount set so that liquid water does not condense in the pipe, and the second dew point is heated by the second dew point meter heater 84 to the exhaust fuel gas. Since the temperature of the meter 34 is raised to a desired temperature, the control temperature in the second dew point meter heater 84 becomes higher than the target temperature of the second dew point meter 34. Further, when the set temperature in the first vaporizer 32 is changed according to the amount of generated water generated in the fuel cell 15 (power generation amount in the fuel cell 15) or the like, the higher the set temperature in the first vaporizer 32, The amount of heat given to the second dew point meter 34 from the exhausted fuel gas increases. Therefore, in such a case, when the heater control temperature in the second dew point meter heater 84 is determined, the set temperature of the first vaporizer 32 may be further taken into consideration.

  As described above, the second piping heater 33 is provided so as to cover the entire flow path connecting the first vaporizer 32 and the second dew point meter 34. Thus, since the exhaust fuel gas is heated in the entire flow path connecting the first vaporizer 32 and the second dew point meter 34, the water vapor in the exhaust fuel gas is not condensed in the flow path, and the first The dew point temperature of the discharged fuel gas can be measured by the second dew point meter 34 in a state where the water vapor amount obtained by evaporating the entire amount of water in the first vaporizer 32 is maintained.

D. Operation when dew point temperature drops:
In the description of the operation related to the heating of the supply gas and the operation related to the heating of the exhaust gas described above, the heater control temperature in each heating unit is set so that the temperature of each dew point meter is higher than the predicted dew point temperature in each gas. By setting, the dew point temperature can be accurately measured in each dew point meter even when the humidity in the gas increases. Here, depending on the operating conditions of the fuel cell 15, the dew point temperature of the gas to be measured by each dew point meter may be greatly reduced beyond prediction. If the dew point temperature of the gas is too low compared to the temperature of the dew point meter, the accuracy of dew point temperature detection by the dew point meter may be reduced. In this example, when the dew point temperature of the gas changes beyond the prediction in this way, the degree of detection accuracy in the dew point meter is changed by changing the degree of heating in the heating section provided upstream of each dew point meter. We are trying to secure it. Hereinafter, an operation of correcting the heating amount in the heating unit when the dew point temperature detected by the dew point meter changes will be described.

  In general, a dew point meter has a lower limit value of the gas temperature at which the dew point temperature can be accurately detected according to the operating principle. FIG. 5 is an explanatory diagram showing a schematic configuration of the first dew point meter 24 which is a mirror surface type dew point meter, but other dew point meters included in the fuel cell evaluation device 10 have the same configuration. The first dew point meter 24 includes a light emitting element 90, a light receiving element 91, a mirror 92, and a Peltier element 93. The light emitting element 90 and the light receiving element 91 are arranged so as to face the mirror 92 with the sampling chamber SC to which the measurement target gas (here, fuel gas) is supplied. Specifically, the light emitting element 90 is arranged so that light can be emitted toward the mirror surface of the mirror 92, and the light receiving element 91 receives light emitted from the light emitting element 90 reflected by the mirror surface of the mirror 92. It is placed in a position where it can be done. The mirror 92 is arranged such that one surface thereof is formed as a mirror surface and exposed to the fuel gas supplied to the sampling chamber SC. The Peltier element 93 is disposed on a surface side different from the mirror surface of the mirror 92, and cools the mirror 92 by a signal from the control unit 70. In the first dew point meter 24, the light emitting element 90 and the light receiving element 91 optically detect that water vapor in the fuel gas is condensed on the mirror surface of the mirror 92 cooled by the Peltier element 93. That is, the mirror surface temperature when dew condensation is started on the mirror surface of the mirror 92 is detected as the dew point temperature of the fuel gas. Thus, in the specular dew point meter, since the Peltier element 93 detects the dew point temperature by cooling the mirror 92 and condensing water vapor in the gas, when the dew point temperature exceeds the cooling capacity of the Peltier element, the dew point temperature is low. May occur when the dew point temperature cannot be accurately detected. That is, when the gas dew point temperature is lower than the temperature at which the detection target gas can be cooled by the Peltier element, there is a possibility that the gas dew point temperature cannot be accurately detected by the dew point meter.

  FIG. 6 is a flowchart showing a heater control temperature correction processing routine that is repeatedly executed by the control unit 70 every predetermined time when the fuel cell 15 is evaluated using the fuel cell evaluation device 10. When this routine is executed, the control unit 70 first refers to the map (in the case of control related to the first dew point meter 24 and the third dew point meter 34, the second dew point is determined according to the map shown in FIG. 2). At the time of the control related to the total meter 34 and the fourth dew point meter 54, the dew point meter heater control temperature Tc is obtained (in accordance with the map shown in FIG. 4) (step S100). Next, the control unit 70 acquires the dew point temperature Td detected by each dew point meter and the detected value of the temperature sensor provided in each dew point meter (hereinafter referred to as dew point meter temperature Ts) (step S105). In the following description, the first dew point meter 24 and the first temperature sensor 83 will be described as an example, but the same control is performed for other combinations of dew point meters and temperature sensors.

  Next, the control unit 70 calculates the lower limit value Tdmin of the dew point temperature that can be accurately measured by the current first dew point meter 24 (step S110). Here, the lower limit value Tdmin is obtained by subtracting the coolable temperature in the Peltier element included in the first dew point meter 24 from the detected dew point meter temperature Ts. The cooling capacity by the Peltier element is generally 40 to 50 ° C. When the coolable temperature is 50 ° C., when the dew point meter temperature Ts acquired in step S105 is 90 ° C., the lower limit value Tdmin is 40 ° C. (= 90 ° C.-50 ° C.).

  Next, the control unit 70 compares the dew point temperature Td acquired in step S105 with the lower limit value Tdmin calculated in step S110 (step S120). When the dew point temperature Td is equal to or higher than the lower limit value Tdmin, it can be determined that the first dew point meter 24 is in a temperature condition that can accurately detect the dew point temperature Td. In step S120, when the dew point temperature Td is equal to or higher than the lower limit temperature Tdmin, the control unit 70 determines whether the control temperature of the dew point meter heater provided in the heating unit has already been corrected (step S130). . The correction of the dew point heater control temperature will be described later.

  If it is determined in step S130 that the dew point meter heater control temperature is not corrected, the control unit 70 maintains the dew point meter heater control temperature Tc obtained in step S100 (step S140). Based on the dew point meter heater control temperature Tc, the energization amount to the first dew point meter heater 82 is controlled (step S210), and this routine is terminated. The operation when it is determined in step S130 that the heater control temperature has been corrected will be described later.

  In step S120, if the dew point temperature Td is less than the lower limit value Tdmin, the first dew point meter 24 has detected a dew point temperature lower than the lower limit dew point temperature that can be detected with high accuracy. Therefore, the control unit 70 next determines whether or not the dew point temperature Td is equal to or higher than (lower limit value Tdmin−10 ° C.) (step S160). When the dew point temperature Td is equal to or higher than the lower limit value Tdmin−10 ° C., the control unit 70 increases the correction amount for the dew point meter heater control temperature Tc obtained in step S100 by one step to increase the dew point meter heater control temperature. This is set (step S170), the energization amount to the first dew point meter heater 82 is controlled (step S210), and this routine is finished.

  Here, a correction pattern for the dew point heater control temperature Tc obtained from the map of FIG. 2 will be described. In this embodiment, when the detected dew point temperature Td falls below the lower limit value Tdmin, correction is performed to set a temperature lower than the dew point meter heater control temperature Tc obtained from the map as the dew point meter heater control temperature. Three stages are prepared as correction stages. Specifically, a first correction for lowering the dew point heater control temperature actually set by 20 ° C. from the dew point meter heater control temperature Tc obtained from the map, a second correction for lowering by 30 ° C., and 40 ° C. A three-stage correction pattern is prepared as a third correction to be lowered. When the correction amount is increased by one step in step S170, for example, when correction is not performed at that time, the dew point meter heater control temperature is 20 ° C. lower than the dew point meter heater control temperature Tc obtained from the map. The first correction pattern to be selected is selected. When the correction has already been performed, if the correction that has already been performed is the first correction pattern, the second correction pattern is used. If the correction is already performed, the third correction pattern is used. The correction pattern for setting the dew point heater control temperature is changed.

  If it is determined in step S160 that the dew point temperature Td is lower than (lower limit value Tdmin-10 ° C.), the controller 70 determines whether the dew point temperature Td is equal to or higher than (lower limit value Tdmin-20 ° C.). It is determined whether or not (step S180). When the dew point temperature Td is equal to or higher than (lower limit value Tdmin−20 ° C.), the control unit 70 increases the correction amount with respect to the dew point heater control temperature Tc obtained in step S100 by two steps to set the dew point meter heater control temperature. This is set (step S190), the energization amount to the first dew point meter heater 82 is controlled (step S210), and this routine is finished. To increase the correction amount by two levels, for example, if correction is not performed at that time, select the second correction pattern that lowers the heater control temperature by 30 ° C. from the dew point heater control temperature Tc obtained from the map To do. If correction has already been performed with the first correction pattern, the correction pattern for setting the dew point meter heater control temperature is changed to the third correction pattern.

  When it is determined in step S180 that the dew point temperature Td is less than (lower limit value Tdmin-20 ° C.), the control unit 70 sets the correction amount for the dew point meter heater control temperature Tc obtained in step S100 in three stages. The dew point heater control temperature is set (step S200), the energization amount to the first dew point heater 82 is controlled (step S210), and this routine is finished. When the correction amount is increased by three levels, if the correction is not performed at that time, the third correction pattern for selecting the dew point meter heater control temperature to be 40 ° C. lower than the heater control temperature Tc obtained from the map is selected.

  In this way, when the dew point temperature Td detected by the dew point meter is below the lower limit value Tdmin that can be accurately detected by the dew point meter, the temperature of the gas flowing in the dew point meter is lowered in order to correct the dew point meter heater control temperature lower. In addition, the amount of heat supplied from the gas to the dew point meter decreases. Thereby, since the dew point meter temperature Ts is lowered, the value of the lower limit value Tdmin obtained by subtracting the coolable temperature by the Peltier element from the dew point meter temperature Ts is also lowered. Therefore, even when the dew point temperature of the gas is low, the dew point temperature is close to a state where the dew point temperature can be detected with high accuracy. In this embodiment, the upper limit value of the correction amount for the dew point meter heater control temperature Tc obtained from the map is set to −40 ° C., and the magnitude of the difference between the dew point temperature Td and the lower limit value Tdmin is set. Three stages of correction patterns are prepared by dividing each by 10 ° C. The upper limit value of the correction amount, the reference value for changing the correction pattern, or the number of correction patterns is determined by the fuel cell evaluation device. What is necessary is just to set suitably according to the characteristic of this.

  If it is determined in step S120 that the dew point temperature Td is equal to or higher than the lower limit value Tdmin, and it is determined in step S130 that the dew point meter heater control temperature has already been corrected, the control unit 70 determines the dew point meter determined in step S100. The correction amount for the heater control temperature Tc is lowered by one step to set the dew point meter heater control temperature (step 150), the energization amount to the first dew point meter heater 82 is controlled (step S210), and this routine is finished. Thereby, when the influence of the fluctuation | variation of the driving | running condition of the fuel cell 15 becomes small, it can approximate to the control state at the time of steady operation.

E. Adjusting the gas flow rate into the dew point meter:
As described above, the supply fuel gas bypass passage 61 branched from the fuel gas supply passage 60 is provided with the first flow rate adjusting valve 27, and the discharged fuel branched from the fuel gas discharge passage 62. The gas bypass passage 63 is provided with a second flow rate adjusting valve 37, and the supply oxidizing gas bypass passage 65 branched from the oxidizing gas supply passage 64 is provided with a third flow rate adjusting valve 47, and the oxidizing gas discharge passage. A fourth flow rate adjusting valve 57 is provided in the exhaust oxidant gas bypass passage 67 that is branched off from 66. By providing each bypass path described above, the gas flow rate flowing through the flow path provided with the first to fourth dew point meters is suppressed, and the gas flow rate flowing into each dew point meter is suppressed. Below, adjustment of the gas flow rate using a bypass flow path provided with such a flow control valve is demonstrated. In the following, the supply fuel gas bypass passage 61 through which the supply fuel gas flows and the first flow rate adjustment valve 27 provided in this flow passage will be described, but the operations in other bypass flow passages and flow rate adjustment valves are also the same. It is.

  Here, the opening degree of the first flow rate adjusting valve 27 provided in the supply fuel gas bypass passage 61 is allowable in order to ensure the accuracy of detection of the flow rate of the fuel gas flowing through the first dew point meter 24 by the first dew point meter 23. It is set not to exceed the upper limit. In the present embodiment, the flow rate of the fuel gas flowing through the first dew point meter 23 even when the conditions of power generation in the fuel cell 15 fluctuate and the amount of exhaust gas discharged from the first vaporizer 32 fluctuates. The opening of the first flow rate adjustment valve 27 is fixed at a constant opening so that the upper limit does not exceed the above upper limit.

  The upper limit of the flow rate of the fuel gas that is acceptable for ensuring the detection accuracy in the first dew point meter 24 is a value determined by the dew point meter used. Hereinafter, an allowable upper limit of the flow rate of the fuel gas in the specular dew point meter used as the first dew point meter 24 in this embodiment will be described. As already described with reference to FIG. 5, when the dew point temperature is detected, the cooling state by the Peltier element 93 is set so that vaporization and condensation are in an equilibrium state in a state where condensation begins to occur on the mirror surface of the mirror 92. The dew point temperature is measured while controlling the water temperature, that is, while maintaining the water balance and the heat balance. In such a dew point meter, when the flow rate of the fuel gas to be measured is too high, so-called blowing (a phenomenon in which condensed liquid water is blown off by a fast gas flow) occurs in the sampling chamber SC, and water balance and heat There is a possibility that the equilibrium state maintaining the balance is lost and the accuracy of the dew point measurement is insufficient. The upper limit fuel gas flow velocity is a value set as the upper limit of the fuel gas flow velocity that can sufficiently suppress such a decrease in detection accuracy. In the present embodiment, the conditions of power generation in the fuel cell 15 fluctuate and the fuel gas flow rate in the mass flow meter 21, the humidification amount in the humidifier 22, or the pressure inside the fuel cell adjusted by the back pressure valve 38 changes. Even if it exists, the opening degree of the 1st flow regulating valve 27 is being fixed to the fixed opening degree so that the gas flow velocity in the 1st dew point meter 23 may not exceed the said upper limit. In addition, when using a humidity sensor of a different system instead of the specular dew point meter, an upper limit of an allowable gas flow rate may be determined for each humidity sensor used in accordance with each detection principle or the like.

  Here, the gas flow velocity is a value obtained by dividing the gas flow rate by the flow path cross-sectional area. In the present embodiment, the flow rate of the fuel gas discharged from the first humidifier 22 is set based on the conditions for evaluating the fuel cell 15, and the supply gas flow rate from the first mass flow meter 21 and the first humidifier. 22 is determined by the amount of humidification. The fuel gas flow path cross-sectional area is the sum of the cross-sectional area of the fuel gas supply path 60 where the first dew point meter 24 is disposed and the cross-sectional area of the supply fuel gas bypass path 61. As described above, in this embodiment, it is possible to suppress the flow velocity of the fuel gas flowing into the first dew point meter 24 by providing the supply fuel gas bypass passage 61 and increasing the cross-sectional area of the fuel gas passage. It has become. In other words, in the present embodiment, the supply fuel gas bypass passage 61 is provided, and the flow rate of the gas flowing through the fuel gas supply passage 60 provided with the first dew point meter 24 is reduced, thereby flowing into the first dew point meter 24. It is possible to suppress the flow rate of the fuel gas.

  Furthermore, in this embodiment, in addition to suppressing the flow rate of the fuel gas flowing into the first dew point meter 24 by branching the flow path and increasing the flow path cross-sectional area, the first flow rate adjustment is performed on the branched flow path. By providing the valve 27, the distribution state of the fuel gas distributed to the fuel gas supply path 60 and the supply fuel gas bypass path 61 can be changed to a desired state. In addition to the first dew point meter 24, the fuel gas supply path 60 is provided with a first pressure gauge 25 and a first flow meter 26, and each sensor can realize sufficient detection accuracy. There are desirable gas flow rates and gas flow rates. In this embodiment, the opening degree of the first flow rate adjusting valve 27 is set, and the flow rate and flow rate of the gas flowing through the fuel gas supply path 60 are set in a desirable range corresponding to each sensor described above. The distribution status is adjusted.

  In addition, suppression of the gas flow rate in the first dew point meter 24 by increasing the cross-sectional area of the flow path can be realized by simply increasing the number of flow paths to be branched without providing the first flow rate adjusting valve 27. It is. In this case, however, the cross-sectional area of the flow path is a sum of the cross-sectional areas of the branched individual flow paths, and can only be changed as a discontinuous value corresponding to the number of flow paths to be branched. Therefore, the distribution ratio of the fuel gas in the flow path provided with each sensor can also be changed only as a discontinuous value corresponding to the number of flow paths to be branched. In contrast, in this embodiment, the gas loss between the fuel gas supply path 60 and the supply fuel gas bypass path 61 is adjusted by adjusting the pressure loss in the supply fuel gas bypass path 61 according to the opening of the first flow rate adjustment valve 27. Can be adjusted, and the flow rate in the fuel gas supply passage 60 provided with each sensor can be changed as a continuous value. Thereby, the gas flow rate in each sensor can be brought closer to a more desirable value.

  Here, in order to control the gas flow rate in the fuel gas supply path 60 provided with each sensor and to continuously control the gas flow rate, for example, without providing a bypass path in the fuel gas supply path 60, the fuel gas A configuration in which a flow rate adjusting valve is provided in the supply path 60 is also possible. However, in this case, the pressure loss increases in the flow rate adjusting valve through which the entire amount of gas passes, so the gas flow rate supplied to the fuel cell 15 and the pressure inside the fuel cell are affected, and the fuel cell evaluation device It becomes difficult to control the operating conditions of the fuel cell as a whole. On the other hand, in the present embodiment, since the flow rate adjustment valve 27 is provided in the supply fuel gas bypass passage 61, the flow rate of the fuel gas in each sensor and the influence of the increase in pressure loss caused by the flow rate adjustment valve 27 are suppressed. The flow rate can be adjusted.

  In addition, the opening degree of the first flow rate adjusting valve 27 may be controlled according to the amount of supplied fuel gas, in addition to the configuration in which the opening degree is fixed at a constant opening degree as described above. That is, as the flow rate of the fuel gas passing through the first humidifier 22 increases, the opening degree of the first flow rate adjustment valve 27 is increased, the flow resistance in the supply fuel gas bypass passage 61 is reduced, and the first dew point meter It is also possible to suppress an increase in the flow velocity of the fuel gas flowing through 24. Alternatively, if the flow rate of the fuel gas does not exceed the upper limit even if the entire amount of the fuel gas that has passed through the first humidifier 22 flows to the first dew point meter 24 side, the first flow rate adjustment valve 27 is closed. It is also good.

  In this embodiment, the first flow rate adjusting valve 27 is provided as a flow rate adjusting unit for adjusting the flow rate of the fuel gas distributed to the first dew point meter 24 and the supply fuel gas bypass passage 61. May be configured differently. For example, a three-way valve as a flow rate adjusting unit is provided at the connection between the fuel gas supply path 60 through which the fuel gas supplied to the first dew point meter 24 flows and the supply fuel gas bypass path 61, and the three-way valve is opened. The flow rate of the fuel gas distributed to the first dew point meter 24 and the supply fuel gas bypass passage 61 may be adjusted by adjusting the degree. A similar effect can be obtained if the flow of the fuel gas can be adjusted so that the flow rate of the fuel gas supplied to the first dew point meter 24 is equal to or lower than the upper limit value allowed by the first dew point meter 24.

F. Operations related to evaluation:
The fuel cell evaluation device 10 is a device for evaluating the relationship between the operating conditions relating to the gas flowing in the fuel cell 15 and the behavior of water in the fuel cell 15. Here, when evaluating the performance of the fuel cell, generally, the output voltage value is measured with respect to the output current value. It can be determined that the higher the output voltage value with respect to the predetermined current value, the better the battery performance. Various factors are conceivable as factors that cause such a decrease in the output voltage value, and examples thereof include an increase in internal resistance and a decrease in gas utilization rate. The increase in the internal resistance of the fuel cell is caused by, for example, an increase in internal resistance in the constituent members of the fuel cell or an increase in contact resistance between the constituent members of the fuel cell. In addition, the decrease in gas utilization rate is caused by, for example, excessive liquid water existing on the electrolyte membrane. Among the various factors that cause the deterioration of the battery performance described above, the increase in internal resistance in the electrolyte membrane, which is a constituent member of the fuel cell, is caused by a lack of moisture in the electrolyte membrane, and is excessively present on the electrolyte membrane. This is a problem related to the movement of water in the electrolyte membrane as well as the problem of liquid water. When performing the evaluation of the fuel cell, by using the fuel cell evaluation apparatus 10 of the present embodiment to examine the behavior of water in the fuel cell, water movement within the fuel cell among the problems related to the cell performance. The problem concerning can be clarified.

  The behavior of water in the fuel cell 15 includes the amount of moisture in the gas supplied to the fuel cell 15, the amount of moisture in the gas discharged from the fuel cell 15, and the generation generated in the fuel cell 15 due to power generation. Judgment based on the amount of water. Normally, in a fuel cell, if power generation is continued under certain conditions, the amount of water in the gas supplied to the fuel cell and the total amount of water produced as a result of power generation are discharged from the fuel cell. It reaches a steady state that balances the amount of water in the gas. In the fuel cell evaluation apparatus 10 of the present embodiment, for example, the behavior of water in the fuel cell in such a steady state, specifically, the behavior of water moving from the cathode side to the anode side in the electrolyte membrane is analyzed. Thus, the performance of the fuel cell can be evaluated.

  Below, the operation | movement which the fuel cell evaluation apparatus 10 analyzes the behavior of the water in the fuel cell 15 is demonstrated. When analyzing the behavior of water in the fuel cell 15, the amount of generated water in the fuel cell 15, the amount of supplied water, the amount of discharged water, and the distribution ratio of water are derived.

  The derivation of the generated water amount in the fuel cell 15 can be theoretically obtained based on the power generation amount in the fuel cell 15 (specifically, the output current value in the fuel cell 15), as described above.

  The amount of water supply in the fuel cell is derived by adding the amount of water vapor (Qvapor1) in the fuel gas supplied to the fuel cell 15 and the amount of water vapor (Qvapor3) in the oxidizing gas supplied to the fuel cell 15. Done. Here, the amount of water vapor (Qvapor1) in the supplied fuel gas supplied to the fuel cell 15 includes the dew point temperature detected by the first dew point meter 24 and the first dew point detected by the first pressure gauge 25, as described above. The water vapor partial pressure (Pvapor1) in the supplied fuel gas obtained from the fuel gas pressure in the meter 24, the total pressure (Ptotal1) of the supplied fuel gas detected by the second pressure gauge 28, and the supplied fuel gas in the first mass flow meter 21 Based on the dry gas flow rate (Qdry1), it can be obtained by equation (3). Similarly, the amount of water vapor (Qvapor3) in the supplied oxidizing gas supplied to the fuel cell 15 is determined by the dew point temperature detected by the third dew point meter 44 and the oxidizing gas pressure in the third dew point meter 44 detected by the fifth pressure gauge 45. The partial pressure of water vapor (Pvapor3) in the supplied oxidizing gas obtained from the above, the total pressure (Ptotal3) of the supplied oxidizing gas detected by the sixth pressure gauge 48, and the dry gas flow rate (Qdry3) of the supplied oxidizing gas in the second mass flow meter 41 Can be obtained by the following equation (6).

  Qvapor3 = Qdry3 × Pvapor3 / (Ptotal3−Pvapor3) (6)

  Derivation of the amount of moisture discharged from the fuel cell 15 is the sum of the amount of water vapor (Qvapor2) in the discharged fuel gas discharged from the fuel cell 15 and the amount of water vapor (Qvapor4) in the discharged oxidizing gas discharged from the fuel cell 15. It is done by doing. Here, the amount of water vapor (Qvapor2) in the discharged fuel gas discharged from the fuel cell 15 is determined by the dew point temperature detected by the second dew point meter 34 and the discharged fuel gas in the second dew point meter 34 detected by the fourth pressure gauge 35. Based on the partial pressure of water vapor (Pvapor2) in the exhaust fuel gas determined from the pressure, the total pressure (Ptotal2) of the exhaust fuel gas detected by the third pressure gauge 31, and the dry gas flow rate (Qdry2) of the exhaust fuel gas, It can obtain | require by the following (7) Formula. Here, the dry gas flow rate (Qdry2) of the discharged fuel gas in the equation (7) is calculated from the dry gas flow rate (Qdry1) of the supplied fuel gas in the first mass flow meter 21, as shown in the following equation (8). 15, the amount of hydrogen consumed by power generation (QconH) is subtracted. As described above, the hydrogen consumption amount (QconH) in the fuel cell 15 can be obtained based on the power generation amount (current density) in the fuel cell 15.

Qvapor2 = Qdry2 × Pvapor2 / (Ptotal2-Pvapor2) (7)
Qdry2 = Qdry1−QconH (8)

  Similarly, the amount of water vapor (Qvapor4) in the exhausted oxidant gas discharged from the fuel cell 15 is determined by the dew point temperature detected by the fourth dew point meter 54 and the exhaust oxidant gas in the fourth dew point meter 54 detected by the eighth pressure gauge 55. Based on the partial pressure of water vapor (Pvapor4) in the exhausted oxidant gas determined from the pressure, the total pressure (Ptotal4) of the exhausted oxidant gas detected by the seventh pressure gauge 51, and the dry gas flow rate (Qdry4) of the exhausted oxidant gas, It can obtain | require by the following (9) Formula. Here, the dry gas flow rate (Qdry4) of the exhausted oxidant gas in the equation (9) is calculated from the dry gas flow rate (Qdry3) of the supplied oxidant gas in the second mass flow meter 41 as shown in the following equation (10). 15 is obtained by subtracting the amount of oxygen consumed by power generation (QconO). The oxygen consumption amount (QconO) in the fuel cell 15 can be obtained based on the power generation amount (current density) in the fuel cell 15 as described above.

Qvapor4 = Qdry4 × Pvapor4 / (Ptotal4-Pvapor4) (9)
Qdry4 = Qdry3−QconO (10)

  Derivation of the distribution ratio of water in the fuel cell 15 is performed by determining the ratio of the generated water generated at the cathode of the fuel cell 15 to each of the anode side and the cathode side. As described above, when the fuel cell continues to generate electricity under certain conditions and reaches a steady state, the water balance in the fuel cell is balanced as a whole. Specifically, the sum of the increase in the moisture content on the discharge side relative to the moisture content on the supply side in the fuel gas and the increase in the moisture content on the discharge side relative to the moisture content on the supply side in the oxidizing gas is Will be equal. In such a state, the increase amount (Qvapor4-Qvapor3) of the discharge-side water vapor amount (Qvapor4) relative to the supply-side water vapor amount (Qvapor3) in the oxidizing gas is vaporized in the oxidizing gas in the generated water generated at the cathode. Reflects the amount of water used. Further, the increase amount (Qvapor2-Qvapor1) of the water vapor amount (Qvapor2) on the discharge side relative to the water vapor amount (Qvapor1) on the supply side in the fuel gas is the electrolyte membrane from the cathode side to the anode side in the generated water generated at the cathode. It moves through and reflects the amount of water vaporized in the fuel gas. Therefore, the distribution ratio of water in the fuel cell 15 is derived by comparing the amount of increase in water vapor on the oxidizing gas side (Qvapor4-Qvapor3) and the amount of water vapor increase on the fuel gas side (Qvapor2-Qvapor1). Done.

  In a fuel cell, if the ratio of generated water discharged through each gas is a close value with no deviation among the gases, the generated water will spread throughout the electrolyte membrane and the electrolyte membrane will be in a good wet state. It is thought that it is maintained. In contrast, when most of the generated water is discharged through one gas and the absolute value of moisture contained in the other gas becomes small, the surface of the electrolyte membrane on the side through which the gas with a small amount of moisture flows is insufficient for water. It can be seen that there is a possibility that the battery performance is lowered due to the drying of the electrolyte membrane. When such an analysis is performed, in the fuel cell 15 to be evaluated, the gas pressure inside the fuel cell, the operating temperature during power generation, the humidification amount of the supply gas, or the power generation amount (output current value) in the fuel cell. The performance of the fuel cell 15 can be evaluated by obtaining the distribution ratio of the generated water while varying the conditions such as

  According to the fuel cell evaluation apparatus 10 of the present embodiment configured as described above, when the dew point temperature of the gas humidified to be supplied to the fuel cell 15 is detected or discharged from the fuel cell 15. When detecting the dew point temperature of the gas from which all liquid water has been vaporized, the state of the gas related to the accuracy when the dew point temperature is detected by the dew point meter is adjusted prior to introduction to the dew point meter. Specifically, the heating amount of the gas is adjusted so that the temperature of the dew point meter heated by the introduced gas is higher than the dew point temperature of the gas and lower than the heat resistance temperature of the dew point meter. In addition, the flow rate of the gas introduced into the dew point meter is suppressed to a flow rate that does not exceed an allowable upper limit in order to ensure the accuracy of the dew point meter. With such a configuration, even if the conditions under which the fuel cell 15 generates power fluctuate, the dew point temperature in the supply gas to the fuel cell 15 or the exhaust gas from the fuel cell 15 can be accurately determined. It becomes possible to measure.

  More specifically, the amount of heating with respect to the gas is adjusted in the heating section so that the temperature of the dew point meter heated by the introduced gas is higher than the predicted dew point temperature of the gas. Even if the conditions under which the battery 15 generates electricity fluctuate, it is possible to suppress a decrease in dew point temperature detection accuracy due to condensation of water vapor in the gas introduced into the dew point meter. In addition, since the amount of heating to the gas is adjusted in the heating section so that the temperature of the dew point meter heated by the introduced gas is lower than the heat resistance temperature of the dew point meter, the temperature of the dew point meter increases. It is possible to suppress deterioration of the durability of the dew point meter due to being too much.

  In addition, the flow rate of the gas introduced into the dew point meter is kept at a flow rate that does not exceed the upper limit that is acceptable to ensure the accuracy of the dew point meter, so the gas flow rate becomes excessive in the dew point meter, and the water balance and heat balance are maintained. It is possible to suppress a decrease in detection accuracy due to the collapse of the balanced state.

  Here, in the fuel cell evaluation device 10 of the present embodiment, prior to each dew point meter, a water vapor containing state adjusting unit that adjusts the state of water in the gas is provided so that the water in the gas exists as water vapor. ing. Specifically, the supply gas flow path for supplying the fuel cell 15 is provided with a humidifier for humidifying the supply gas so as to have a desired humidity, and the exhaust gas flow discharged from the fuel cell 15 is provided. In the road, a vaporizer is provided for vaporizing the entire amount of liquid water in the flow path. In the present embodiment, the heating unit described above is provided so as to heat the entire flow path connecting the water vapor containing state adjusting unit such as a humidifier or a vaporizer and the dew point meter. Even if the conditions vary, the water vapor in the gas will not condense on the way, and the dew point temperature is measured with a dew point meter while maintaining the water vapor content state adjusted by the water vapor content state adjustment unit. can do.

  In particular, on the exhaust gas side, a vaporizer is provided as a water vapor-containing state adjusting unit to vaporize all the water in the gas. Therefore, for example, when the amount of power generation in the fuel cell 15 increases and the amount of water in the exhaust gas (the total amount of water vapor and liquid water) increases, or the stoichiometric ratio (theoretical required amount of gas required in the supply gas) Even if the amount of water in the exhaust gas (the sum of the amount of water vapor and liquid water) is large, the amount of water in the exhaust gas is determined as the amount of water vapor in the dew point meter. Specifically, it can be accurately detected as the dew point temperature for obtaining the humidity which is the water vapor concentration.

  In this way, on the exhaust gas side, in order to heat the exhaust gas supplied to the dew point meter, the vaporizer that heats at high temperature in order to vaporize all the water in the exhaust gas, and the temperature of the dew point meter to the target temperature In order to do this, a heating unit that performs heating is combined. Therefore, it is possible to secure a state where all the water is vaporized by the vaporizer and to improve the reliability of the operation of supplying the gas at a desired temperature to the dew point meter without exceeding the heat resistance temperature of the dew point meter by the heating unit. it can.

  Further, in the fuel cell evaluation device 10 of this embodiment, when adjusting the temperature of the gas supplied to the dew point meter as described above, the dew point temperature of the gas is predicted to control the heating amount in the heating unit. Yes. Therefore, even if the conditions relating to the power generation of the fuel cell 15 fluctuate, it is possible to suppress undesirable dew condensation in the dew point meter and to ensure the detection accuracy of the dew point temperature. Here, especially in exhaust gas, the dew point temperature fluctuates depending on the amount of generated water accompanying power generation and the amount of electrode active material (hydrogen or oxygen) consumed by power generation. Specifically, the stoichiometric ratio of the gas supplied to the fuel cell 15 (the amount of gas actually supplied with respect to the theoretically required amount of gas), the power generation amount, and the distribution ratio of generated water inside the fuel cell 15 The dew point temperature in the exhaust gas varies depending on (a ratio between the amount of generated water vaporized on the fuel gas side and the amount of generated water vaporized on the oxidizing gas side). Thus, even if the dew point temperature fluctuates, the stoichiometric ratio (in the embodiment, the supplied dry gas flow rate and the amount of electrode active material consumed by power generation), the power generation amount, Since the dew point temperature is predicted based on the distribution ratio in the fuel cell 15 and the heating amount in the heating unit is set, the accuracy of the dew point temperature measurement in the dew point meter can be sufficiently ensured.

  Further, in the fuel cell evaluation device 10 of the present embodiment, the gas flow rate is controlled when the heating unit is controlled so that the temperature in the dew point meter that receives the supply of heat from the gas is equal to or higher than the dew point temperature predicted as described above. Based on this, the heating amount in the heating unit is adjusted. For this reason, it is possible to suppress the temperature of the dew point meter from being excessively increased due to the excessive gas flow rate, or the dew point meter from being sufficiently secured due to the insufficient gas flow rate to cause dew condensation. Here, the flow rate of the supply gas can be adjusted with relatively high accuracy by setting the mass flow meters 21 and 41 and the humidifiers 22 and 42. On the other hand, the flow rate of the exhaust gas decreases as the electrode active material is consumed by power generation, and increases as the generated water evaporates. Can vary. In this embodiment, the amount of exhaust gas is calculated in consideration of the above-mentioned fluctuation factors, and the heating amount in the heating unit is controlled. Therefore, even if the power generation conditions fluctuate, the dew point meter temperature is set to a desired temperature range. Thus, the dew point temperature can be accurately detected.

  Furthermore, in the fuel evaluation apparatus 10 of the present embodiment, based on the dew point temperature Ts, the dew point meter obtains a lower limit value Tdmin that enables accurate detection of the dew point temperature. When the dew point temperature Td falls below the lower limit value Tdmin, heating is performed. The temperature of the dew point meter is lowered by controlling the heating unit so that the amount of heating in the unit decreases, and suppressing the amount of heat supplied from the gas to the dew point meter. In this way, even if the dew point temperature Ts of the gas to be detected varies greatly between a high state and a low state by changing the dew point meter temperature Ts according to the measured dew point temperature Td, It becomes possible to ensure the accuracy of dew point temperature detection.

G. Variation:
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.

G1. Modification 1:
In the embodiment, a dew point meter provided with a pressure gauge is used as the humidity sensor, but different types of humidity sensors may be used. Even when another type of humidity sensor is used, the present invention is applied to adjust the state related to the accuracy of detection by the humidity sensor, such as the temperature and flow rate of the gas supplied to the humidity sensor, so that the fuel cell Even if the conditions relating to the power generation vary, it is possible to ensure the accuracy of humidity detection of the gas supplied to the fuel cell or the gas discharged from the fuel cell.

G2. Modification 2:
In the embodiment, each heating unit is constituted by a pipe heater and a dew point meter heater, and the heating amount by the pipe heater is fixed, while the heating amount by the dew point meter heater is changed based on the gas flow rate or the like. A different configuration may be used. For example, instead of the dew point meter heater, the heating amount of the piping heater may be changed, or both the heating amount of the piping heater and the heating amount of the dew point meter heater may be changed. By controlling the heating amount of the heating unit as a whole for the gas supplied to the humidity sensor in the same manner as in the embodiment based on the gas flow rate or the like, the same effect as in the embodiment can be obtained.

G3. Modification 3:
The configuration of each part of the fuel cell evaluation device 10 can be variously modified with respect to the embodiment. For example, the order of arrangement of the pressure gauge and the dew point gauge may be an order different from that of the embodiment. In order to suppress an error between the pressure of the gas at which the dew point meter measures the dew point temperature and the gas pressure detected by the pressure gauge, the dew point meter and the pressure gauge may be arranged close enough.

  In the embodiment, the control unit 70 included in the fuel cell evaluation apparatus 10 derives the amount of generated water, the amount of supplied water, the amount of discharged water, and the water for evaluating the fuel cell 15. Although the distribution ratio is derived, different configurations may be used. For example, the fuel cell evaluation apparatus 10 may only acquire information related to the operating conditions of the fuel cell, the amount of water in the supply gas, the amount of water in the exhaust gas, and the amount of generated water. And it is good also as a separate apparatus to perform the process for evaluation of a fuel cell including derivation | leading-out of the behavior (distribution ratio of produced water) in the electrolyte membrane mentioned above based on the acquired information. .

G4. Modification 4:
In the embodiment, the fuel cell evaluation apparatus 10 is used, but the present invention may be applied to an apparatus having a different configuration. For example, the present invention may be applied to a fuel cell system used as a power source for supplying power to a load. That is, the present invention can be applied to a fuel cell system mounted as a driving power source on a moving body such as a vehicle or a fuel cell system as a stationary power generator. When a humidity sensor is provided in the gas flow path in order to detect and monitor the amount of water vapor in the flow path of the gas supplied to the fuel cell and / or the gas flow path discharged from the fuel cell, By applying the present invention, the same effect can be obtained that improves the accuracy of humidity detection in gas, ensures the durability of the humidity sensor, and increases the reliability of the sensor. As described above, in the fuel cell system, when the amount of water vapor in the gas supplied to the fuel cell or the gas discharged from the fuel cell is detected and monitored, the fuel cell used is a fuel other than the polymer electrolyte fuel cell. A battery may be used. For example, when a fuel cell other than a solid polymer fuel cell is used, such as a solid oxide fuel cell, there is no movement of water in the electrolyte membrane, but the amount of water vapor in the supply gas or exhaust gas is accurately determined. By being able to detect, such a detection result can be used for, for example, determination of occurrence of flooding in the fuel cell and operation control for suppressing flooding.

2 is a block diagram showing a schematic configuration of a state in which a fuel cell 15 is attached to the fuel cell evaluation device 10. FIG. It is explanatory drawing showing the relationship between supply fuel gas flow volume and heater control temperature. It is explanatory drawing which shows collectively the relationship between a flow volume and pressure about each of the fuel gas and oxidizing gas which are supplied / discharged with respect to the fuel cell. It is explanatory drawing showing the relationship between exhaust fuel gas flow volume and heater control temperature. It is explanatory drawing showing the schematic structure of the 1st dew point meter 24 which is a mirror surface type dew point meter. It is a flowchart showing a heater control temperature correction processing routine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell evaluation apparatus 15 ... Fuel cell 20 ... Fuel gas supply part 21 ... 1st mass flow meter 22 ... 1st humidifier 23 ... 1st piping heater 24 ... 1st dew point meter 25 ... 1st pressure gauge 26 ... 1st flow rate Total 27 ... 1st flow control valve 28 ... 2nd pressure gauge 29 ... 1st temperature control part 30 ... Oxidation gas supply part 31 ... 3rd pressure gauge 32 ... 1st vaporizer 33 ... 2nd piping heater 34 ... 2nd dew point 35 ... 4th pressure gauge 36 ... 2nd flow meter 37 ... 2nd flow control valve 38 ... 1st back pressure valve 40 ... Oxidizing gas supply part 41 ... 2nd mass flow meter 42 ... 2nd humidifier 43 ... 3rd piping heater 44 3rd dew point meter 45 ... 3rd pressure gauge 46 ... 3rd flow meter 47 ... 3rd flow rate adjustment valve 49 ... 2nd temperature control part 52 ... 2nd vaporizer 53 ... 4th piping heater 54 ... 4th dew point meter 56 ... 4th flow meter 57 ... 4th flow adjustment bar Lub 58 ... second back pressure valve 60 ... fuel gas supply path 61 ... supply fuel gas bypass path 62 ... fuel gas discharge path 63 ... exhaust fuel gas bypass path 64 ... oxidant gas supply path 65 ... supply oxidant gas bypass path 66 ... oxidant gas Discharge path 67 ... Exhaust oxidizing gas bypass path 68,69 ... 3-way valve 70 ... Control unit 80 ... First humidified gas branch path 81 ... Second humidified gas branch path 82 ... First dew point meter heater 83 ... First temperature sensor 84 ... Second dew point heater 85 ... Second temperature sensor 86 ... Third dew point heater 87 ... Third temperature sensor 88 ... Fourth dew point meter heater 89 ... Fourth temperature sensor 90 ... Light emitting element 91 ... Light receiving element 92 ... Mirror 93 ... Peltier element

Claims (12)

A fuel cell system comprising a fuel cell,
A humidity sensor provided in a gas flow path connected to the fuel cell;
In the flow path, provided in the upstream of the flow of the gas from the humidity sensor, a water vapor containing state adjusting unit that adjusts the state of moisture in the gas so that the moisture in the gas exists as water vapor,
For the gas flowing from the water vapor-containing state adjusting unit to the humidity sensor, a gas state adjusting unit that adjusts the state of the gas according to accuracy when the humidity is detected by the humidity sensor;
A fuel cell system comprising: The fuel cell system according to claim 1, wherein
The state adjusted by the gas state adjusting unit is a flow rate and / or temperature of the gas supplied to the humidity sensor. The fuel cell system according to claim 2, wherein
The state adjusted by the gas state adjusting unit is the temperature of the gas,
The gas condition adjustment unit is configured such that the temperature of the humidity sensor that receives heat supply from the gas via the water vapor content condition adjustment unit is higher than a dew point temperature predicted for the gas, and the humidity sensor allows an upper limit. A fuel cell system, which is a heating unit that heats the gas so that the temperature is lower than a temperature. The fuel cell system according to claim 3, wherein
The said heating part is provided with the piping heater which heats the said gas by heating the whole piping which connects the said water vapor containing state adjustment part and the said humidity sensor. Fuel cell system. The fuel cell system according to claim 3 or 4, wherein
The gas flow path provided with the humidity sensor is a flow path through which the gas discharged from the fuel cell flows,
The fuel cell system further includes:
Based on the amount of water produced in the fuel cell, the assumed distribution of water in the fuel cell, the flow rate of gas supplied to the fuel cell, and the flow rate of gas consumed in the fuel cell, A dew point temperature predicting unit for predicting the dew point temperature of the gas flowing to the humidity sensor;
The heating unit heats the gas so that the temperature of the humidity sensor is higher than the dew point temperature predicted by the dew point temperature prediction unit. A fuel cell system according to any one of claims 3 to 5,
The humidity sensor is a dew point meter that detects a dew point temperature of the gas,
The said heating part changes the grade of the heating with respect to the said gas according to the dew point temperature which the said dew point meter detected. Fuel cell system. The fuel cell system according to claim 6, wherein
When the dew point temperature detected by the dew point meter is lower than a lower limit temperature allowed by the dew point meter, the heating unit reduces the degree of heating of the gas according to a difference between the dew point temperature and the lower limit temperature. Fuel cell system. The fuel cell system according to claim 2, wherein
The state adjusted by the gas state adjusting unit is a flow rate of the gas,
The gas state adjusting unit is
A bypass flow path that is provided in communication with the water vapor-containing state adjusting unit and guides the gas without passing through the humidity sensor;
A flow rate adjusting unit for adjusting a flow rate of the gas distributed to the humidity sensor and the bypass flow path so that a flow rate of the gas supplied to the humidity sensor is equal to or lower than an upper limit value allowed by the humidity sensor; A fuel cell system comprising: A fuel cell system according to any one of claims 1 to 8,
The gas flow path provided with the humidity sensor is a flow path through which the gas discharged from the fuel cell flows,
The water vapor-containing state adjusting unit is a vaporizer that heats the gas discharged from the fuel cell and vaporizes the entire amount of liquid water present in the gas. A fuel cell system according to any one of claims 1 to 4 and 8,
The flow path of the gas provided with the humidity sensor is a flow path through which the gas supplied to the fuel cell flows,
The water vapor-containing state adjusting unit is a humidifier that humidifies a gas supplied to the fuel cell. The fuel cell system according to any one of claims 1 to 10, further comprising:
A fuel cell system comprising a fuel cell evaluation unit for evaluating the behavior of water in the fuel cell based on a detection value in the humidity sensor. A fuel cell evaluation apparatus for evaluating the behavior of water in a fuel cell,
A first humidity sensor provided in a flow path of a supply fuel gas supplied to the fuel cell;
A second humidity sensor provided in a flow path of a supply oxidizing gas supplied to the fuel cell;
A third humidity sensor provided in a flow path of exhaust fuel gas discharged from the fuel cell;
A fourth humidity sensor provided in a flow path of exhausted oxidant gas discharged from the fuel cell;
Provided upstream of the humidity sensor in the flow path of each of the supply fuel gas, the supply oxidant gas, the exhaust fuel gas, and the exhaust oxidant gas, the fuel cell A water vapor-containing state adjusting unit that adjusts the state of water in the gas so that water in the gas supplied or water in the gas discharged from the fuel cell exists as water vapor;
For the gas supplied from the water vapor containing state adjusting unit to the humidity sensor, a gas state adjusting unit that adjusts the state of the gas according to accuracy when the humidity is detected by the humidity sensor;
A fuel cell evaluation apparatus comprising:

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