JP2011065985A - Fuel cell diagnosis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To diagnose power generation condition of a plurality of power generation cells of a fuel cell with a simple structure and without giving an adverse effect to the power generation performance of the fuel cell. <P>SOLUTION: The fuel cell diagnosis device is provided with a pair of magnetic sensors 53, 54 which are arranged at two places around the outer periphery of power generation cells 10 and detect intensity of the magnetic field formed at the outer circumference of the fuel cell 1 by electric current flowing in the fuel cell 1, magnetic collectors 531, 541 which are arranged adjacent to the magnetic sensors 53, 54 at the outer periphery of the fuel cell 1, extend along the lamination direction of the plurality of power generation cells 10, and collect the magnetic field formed at the outer circumference of the plurality of power generation cells 10 to the magnetic sensors 53, 54, and a diagnosis means (control device) 50 which calculates deviation of current (magnetic force difference) in the cell surface of the plurality of power generation cells 10 by the detection value detected by the pair of magnetic sensors 53, 54, and diagnoses the power generation condition of the fuel cell 1 based on the deviation of current (magnetic force difference) calculated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell diagnostic apparatus for diagnosing a power generation state of a fuel cell in which a plurality of power generation cells that emit electrical energy are stacked.

  2. Description of the Related Art Conventionally, a fuel cell is known in which a plurality of power generation cells that generate electric energy by electrochemical reaction of a fuel gas containing hydrogen and an oxidant gas containing oxygen are known. In a fuel cell, the output voltage (power generation performance) of the battery decreases when the supply amount of reaction gas such as fuel gas and oxidant gas is insufficient. It is necessary to maintain a stable power generation state.

  For this reason, a conductive plate with a built-in magnetic sensor or the like is provided inside the fuel cell (between stacked power generation cells), and the current in a local region within the power generation cell surface is measured to diagnose a lack of reaction gas in the fuel cell. Has been proposed (for example, Patent Document 1).

JP-A-2005-123162

  By the way, in the configuration in which the power generation state is diagnosed by the conductive plate provided inside the fuel cell as in Patent Document 1, the conductive plate itself becomes a resistance during power generation, which may adversely affect the power generation performance of the fuel cell.

  Moreover, in patent document 1, since it is the structure which arrange | positions a conductive plate between the power generation cells which diagnose a power generation state, when diagnosing the reaction gas shortage between several power generation cells collectively, a conductive plate is used between each power generation cell. It is necessary to provide. In this case, the number of conductive plates necessary for diagnosing the power generation state increases, and the configuration for diagnosing the power generation state of the fuel cell becomes complicated.

  An object of the present invention is to provide a fuel cell diagnostic apparatus capable of diagnosing the power generation state of a plurality of power generation cells of a fuel cell with a simple configuration without adversely affecting the power generation performance of the fuel cell. To do.

  In order to achieve the above object, according to the first aspect of the present invention, the power generation state of the fuel cell (1) in which a plurality of power generation cells (10) that generate electricity by electrochemical reaction of an oxidant gas and a fuel gas is stacked is diagnosed. A fuel cell diagnostic device that is arranged in a circumferentially shifted position around the outer periphery of the power generation cell (10) and is formed around the outer periphery of the fuel cell (1) by a current flowing in the fuel cell (1). A pair of magnetic field detecting means (53, 54) for detecting the strength of the magnetic field, and arranged adjacent to the magnetic field detecting means (53, 54) on the outer periphery of the fuel cell (1), the plurality of power generation cells (10) A magnetic current collector (531, 541) that extends along the stacking direction and collects magnetic fields formed around the outer periphery of the plurality of power generation cells (10) in the magnetic field detection means (53, 54), and a pair of magnetic field detection means (53 , 54) It characterized in that it comprises a and a diagnosis means (50) for diagnosing the power generation state of the fuel cell (1) based on the detection value.

  According to this, the power generation state of the fuel cell (1) is based on the detection values of the pair of magnetic field detection means (53, 54) arranged around the outer periphery of the power generation cell (10), that is, outside the fuel cell (1). Therefore, the power generation performance of the fuel cell (1) is not adversely affected.

  Further, by providing the current collectors (531, 541), the magnetic field formed around the outer periphery of the plurality of power generation cells (10) can be collectively detected by the magnetic field detection means (53, 54). Even when the power generation state of the cell (10) is diagnosed collectively, there is no need to increase the configuration for diagnosing the power generation state of the fuel cell (1).

  Therefore, the power generation state of the plurality of power generation cells (10) of the fuel cell (1) can be diagnosed with a simple configuration without adversely affecting the power generation performance of the fuel cell (1). When the power generation state of the power generation cell (10) is normal, the detection values of the pair of magnetic field detection means (53, 54) arranged to be shifted in the circumferential direction are equal. However, when the power generation state is abnormal, the detection values of the pair of magnetic field detection means (53, 54) are different. That is, when the detection values of the pair of magnetic field detection means (53, 54) are different from each other, it can be diagnosed that the power generation state of the power generation cell (10) is abnormal.

  Specifically, as in the invention according to claim 2, in the fuel cell diagnostic device according to claim 1, the magnetic collector (531, 541) is a length in the stacking direction of the plurality of power generation cells (10). (L) can be configured to be longer than the thickness (T) in the stacking direction of the power generation cell (10).

  In the invention according to claim 3, the power generation cell (10) includes a fuel gas upstream portion closer to the inlet (121a) than the fuel gas outlet (121b) in the cell plane, and an oxidant gas inlet (122a). ) And the downstream portion of the oxidant gas closer to the outlet (122b) than in the stacking direction, and the downstream portion of the fuel gas closer to the outlet (121b) than the inlet (121a) of the fuel gas in the cell plane. The upstream portion of the oxidant gas closer to the inlet (122a) than the outlet (122b) is configured to face in the stacking direction, and the pair of magnetic field detecting means (53, 54) includes one magnetic field detecting means (53 ) Are disposed at positions near the fuel gas upstream portion and the oxidant gas downstream portion on the outer periphery of the power generation cell (10), and the other magnetic field detection means (54) is the fuel gas on the outer periphery of the power generation cell (10). The diagnostic means (50) is arranged so that the detected value of the other magnetic field detecting means (54) is different from the detected value of the one magnetic field detecting means (53). When the fuel gas is deficient when it is decreased by a predetermined first set value or more, the detection of one magnetic field detection means (53) is detected with respect to the detection value of the other magnetic field detection means (54). It is characterized that the oxidant gas is deficient when the value is decreased by a predetermined second set value or more.

  According to this, the power generation state of the fuel cell (1) such as whether or not the fuel gas is deficient and whether or not the oxidant gas is deficient is detected by the pair of magnetic field detecting means (53, 54). Based on this, it is possible to make a specific diagnosis. Therefore, the power generation state of the plurality of power generation cells (10) of the fuel cell (1) can be diagnosed with a simpler configuration. The “cell surface” means a surface orthogonal to the stacking direction of the plurality of power generation cells (10) in the power generation cell (10).

  According to a fourth aspect of the present invention, in the fuel cell diagnostic apparatus according to the first or second aspect, the pair of magnetic field detecting means (53a, 54a) is configured such that one of the magnetic field detecting means (53a) is a power generation cell (10). ) Is disposed at a position closer to the upstream portion of the fuel gas closer to the inlet (121a) than to the outlet (121b) of the fuel gas in the cell surface, and the other magnetic field detection means (54a) is located at the outer periphery of the power generation cell (10). In the cell plane, the fuel gas is positioned closer to the downstream portion of the fuel gas closer to the outlet (121b) than the fuel gas inlet (121a), and the diagnostic means (50) detects the one magnetic field detecting means (53a). When the detected value of the other magnetic field detecting means (54a) is decreased by a predetermined first set value or more with respect to the value, it is diagnosed that the fuel gas is deficient.

  According to this, the power generation state of the fuel cell (1), such as whether or not the fuel gas is deficient, can be specifically diagnosed based on the detection values of the pair of magnetic field detection means (53a, 54a). .

  According to the fifth aspect of the present invention, in the fuel cell diagnostic apparatus according to the first or second aspect, the pair of magnetic field detection means (53b, 54b) is configured such that one of the magnetic field detection means (53b) is a power generation cell (10). ) Is disposed at a position closer to the downstream portion of the oxidant gas nearer to the outlet (122b) than to the inlet (122a) of the oxidant gas in the cell surface, and the other magnetic field detection means (54b) serves as the power generation cell (10). Is disposed at a position nearer to the downstream side of the oxidant gas, closer to the inlet (122a) than to the outlet (122b) of the oxidant gas in the cell surface, and the diagnostic means (50) has the other magnetic field detection means ( 54b), when the detected value of one of the magnetic field detecting means (53b) is decreased by a predetermined second set value or more, it is diagnosed that the oxidant gas is deficient. To do.

  According to this, it is possible to specifically diagnose the power generation state of the fuel cell (1), such as whether or not the oxidant gas is deficient, based on the detection values of the pair of magnetic field detection means (53b, 54b). it can.

  Moreover, in the fuel cell diagnostic apparatus according to any one of claims 1 to 5, as in the invention described in claim 6, resistance measuring means (50 to 50) for measuring the internal resistance in the fuel cell (1). 52), and when the measured value measured by the resistance measuring means (50 to 52) is larger than a preset resistance value, the diagnostic means (50) dries the inside of the fuel cell (1). If so, it can be configured to diagnose the condition.

  Here, in addition to the magnetic field due to the current flowing through the fuel cell (1), a magnetic field due to geomagnetism is formed around the fuel cell (1). In addition, the direction of the magnetic flux by geomagnetism becomes one specific direction.

  For this reason, when the strength of the magnetic field due to the current flowing through the fuel cell (1) is not sufficiently large compared to the strength of the magnetic field due to geomagnetism, the pair of magnetic field detection means (53, 54) is caused by the influence of geomagnetism. There is a possibility that the diagnosis of the power generation state of the fuel cell based on this cannot be performed properly.

  Therefore, according to a seventh aspect of the present invention, in the fuel cell diagnostic apparatus according to any one of the first to sixth aspects, the pair of magnetic field detecting means (53, 54) is provided around the outer periphery of the power generation cell (10). And a positive magnetic field strength that is in the same direction as the direction of the magnetic flux generated in the outer periphery of the fuel cell (1) by the current flowing in the fuel cell (1). Detecting and diagnosing means (50) is preset with the sum of the detected value detected by one magnetic field detecting means (53) and the detected value detected by the other magnetic field detecting means (54). When it is smaller than the first reference value, the power generation state of the fuel cell (1) is diagnosed based on the detection values detected by the pair of magnetic field detection means (53, 54).

  According to this, since the pair of magnetic field detection means (53, 54) is arranged at a position shifted by a half turn in the circumferential direction around the outer periphery of the power generation cell (10), the current flowing in the fuel cell (1) The direction of the magnetic flux generated in the outer periphery of the fuel cell (1) is opposite between the periphery of the first magnetic field detection means (53) and the periphery of the second magnetic field detection means (54). On the other hand, the direction of the magnetic flux due to geomagnetism is the same direction around the first magnetic field detecting means (53) and around the second magnetic field detecting means (54).

  And each of a pair of magnetic field detection means (53, 54) makes positive the intensity | strength of the magnetic field which becomes the same direction as the direction of the magnetic flux produced in the outer periphery of a fuel cell (1) by the electric current which flows through the inside of a fuel cell (1). Therefore, one of the pair of magnetic field detection means (53, 54) detects the strength of the magnetic field due to geomagnetism as positive and the other as the negative strength of the magnetic field due to geomagnetism.

  For this reason, by adding the detection values of the pair of magnetic field detection means (53, 54), the strength of the magnetic field due to geomagnetism contained in the detection value of one magnetic field detection means (53) and the other magnetic field detection means ( 54) and canceling out the strength of the magnetic field by the geomagnetism contained in the detected value.

  Then, when the sum of the detection values in the pair of magnetic field detection means (53, 54) excluding the influence of geomagnetism is low, the fuel cell is based on the detection values detected by the pair of magnetic field detection means (53, 54). Since the power generation state of (1) is diagnosed, even if the strength of the magnetic field due to the current flowing through the fuel cell (1) is not sufficiently larger than the strength of the magnetic field due to geomagnetism, a pair of magnetic field detection means ( 53, 54), it is possible to appropriately diagnose the power generation state of the fuel cell (1).

  Further, according to claim 8, in the fuel cell diagnostic apparatus according to any one of claims 1 to 6, the pair of magnetic field detecting means (53, 54) are arranged in a circumferential direction around the outer periphery of the power generation cell (10). It is arranged at a position shifted by half a circle, and the magnetic field strength that is in the same direction as the direction of the magnetic flux generated in the outer periphery of the fuel cell (1) due to the current flowing in the fuel cell (1) is detected as negative and diagnosed. The means (50) includes a detection value detected by one of the magnetic field detection means (53) and a detection value detected by the other magnetic field detection means (54) of the pair of magnetic field detection means (53, 54). The power generation state of the fuel cell (1) is diagnosed based on the detection values detected by the pair of magnetic field detection means (53, 54) when the total value of the two is larger than a preset second reference value It is characterized by.

  This also cancels out the strength of the magnetic field due to geomagnetism, so even if the strength of the magnetic field due to the current flowing through the fuel cell (1) is not sufficiently large compared to the strength of the magnetic field due to geomagnetism, The power generation state of the fuel cell (1) can be appropriately diagnosed based on the magnetic field detection means (53, 54).

  According to a ninth aspect of the present invention, in the fuel cell diagnostic apparatus according to any one of the first to sixth aspects, the pair of magnetic field detecting means (53, 54) is provided around the outer periphery of the power generation cell (10). Is disposed at a position shifted by a half turn in the circumferential direction of the fuel cell (1), and one of the pair of magnetic field detection means (53, 54) is driven by the current flowing in the fuel cell (1) by one of the magnetic field detection means (53). 1) The strength of the magnetic field in the same direction as the direction of the magnetic flux generated in the outer periphery is detected as positive, and the strength of the magnetic field in the same direction as the direction of the magnetic flux is negative in the other magnetic field detection means (54). The subtracting value obtained by subtracting the detection value detected by the other magnetic field detection means (54) from the detection value detected by the one magnetic field detection means (53) is preset by the detection means (50). If the third reference value is smaller than And wherein the diagnosing the power generation state of the fuel cell (1) based on the detected value detected by the field detecting means (53, 54).

  This also cancels out the strength of the magnetic field due to geomagnetism, so even if the strength of the magnetic field due to the current flowing through the fuel cell (1) is not sufficiently large compared to the strength of the magnetic field due to geomagnetism, The power generation state of the fuel cell (1) can be appropriately diagnosed based on the magnetic field detection means (53, 54).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a perspective view showing a fuel cell and a fuel cell diagnostic device according to a first embodiment. It is sectional drawing which shows schematic structure of the cell of the fuel battery | cell of FIG. It is explanatory drawing explaining the magnetic field formed in the outer periphery of a fuel cell. It is explanatory drawing for demonstrating the length of the lamination direction of the cell of a magnetic current collector. It is a flowchart which shows the diagnostic process of the control apparatus which concerns on 1st Embodiment. It is a perspective view which shows the fuel cell and fuel cell diagnostic apparatus which concern on 2nd Embodiment. It is a perspective view which shows the fuel cell and fuel cell diagnostic apparatus which concern on 3rd Embodiment. It is explanatory drawing for demonstrating the geomagnetism formed in the circumference | surroundings of a fuel cell. It is a flowchart which shows the diagnostic process of the control apparatus which concerns on 4th Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing a fuel cell and a fuel cell diagnostic apparatus according to the present embodiment.

  The fuel cell diagnostic device 5 of the present invention is a diagnostic device for diagnosing the power generation state of the fuel cell 1 in which a plurality of power generation cells (hereinafter referred to as cells or single cells) 10 are stacked.

  First, the fuel cell 1 according to the present embodiment will be described. The fuel cell 1 according to the present embodiment can be used in an on-vehicle power generation system of a so-called fuel cell vehicle, which is a kind of electric vehicle, and supplies power to an electric load such as an electric motor for vehicle travel. In the present embodiment, an example in which a solid polymer electrolyte fuel cell is used as the fuel cell 1 will be described.

  As shown in FIG. 1, the fuel cell 1 has a stack structure in which a plurality of single cells 10 as basic units are stacked. The stacked cells 10 are electrically connected in series. And the electric current obtained by generating electric power in each cell 10 is collected by the current collecting plate 10a provided in the both ends of the laminated | stacked cell 10, and is supplied to electric power apparatuses 4, such as an electrical load.

  On one side surface (current collector plate 10a) of the fuel cell 1, a hydrogen inlet 1a, an air inlet 1b, a hydrogen outlet 1c, and an air outlet 1d are provided. The hydrogen inlet 1 a constitutes an inlet for introducing a fuel gas containing hydrogen (hereinafter simply referred to as hydrogen) into the fuel cell 1, and the air inlet 1 b provides oxygen into the fuel cell 1. An inlet for introducing the contained oxidant gas (hereinafter referred to as air) is configured. The hydrogen outlet 1c constitutes a discharge port for discharging hydrogen from the inside of the fuel cell 1 to the outside, and the air outlet 1d constitutes a discharge port for discharging air from the inside of the fuel cell 1 to the outside. Yes.

  The hydrogen inlet 1 a communicates with a hydrogen supply path 2 a for supplying hydrogen to the hydrogen electrode side of the fuel cell 1, and the hydrogen outlet 1 c externally generates water accumulated on the hydrogen electrode side from the fuel cell 1 together with a small amount of hydrogen. To the hydrogen discharge path 2b for discharging to

  A high-pressure hydrogen tank (not shown) filled with high-pressure hydrogen is provided at the most upstream part of the hydrogen supply path 2a, and the fuel cell 1 is interposed between the high-pressure hydrogen tank and the fuel cell 1 in the hydrogen supply path 2a. A hydrogen pressure regulating valve (not shown) for adjusting the pressure of the supplied hydrogen is provided. The hydrogen discharge path 2b is provided with a solenoid valve (not shown) or the like for discharging impurities such as generated water and nitrogen that have passed through the electrolyte membrane of each cell 10 from the air electrode side to the outside air together with unreacted hydrogen. ing.

  The air inlet 1 b communicates with an air supply path 3 a for supplying air to the air electrode side of the fuel cell 1, and the air outlet 1 d is generated by surplus air and the air electrode that have finished the electrochemical reaction in the fuel cell 1. The generated product water communicates with an air discharge path 3b for discharging the generated water from the fuel cell 1 to the outside.

  An air pump (not shown) for pumping air sucked from the atmosphere to the fuel cell 1 is provided at the most upstream part of the air supply path 3a, and the air in the fuel cell 1 is provided in the air discharge path 3b. An air pressure regulating valve (not shown) for adjusting the pressure is provided.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the cell 10 of the fuel cell 1 according to the present embodiment. As shown in FIG. 2, the cell 10 of this embodiment includes an electrolyte / electrode assembly (hereinafter referred to as “a pair of electrodes”) in which a pair of electrodes (hydrogen electrode, air electrode) are arranged on both sides of an electrolyte membrane mainly composed of a solid polymer membrane. (Referred to as a membrane electrode assembly) 11 and a separator 12 disposed on both outer sides of the membrane electrode assembly 11.

  The separator 12 is formed with a hydrogen inlet manifold 121a that communicates with the hydrogen inlet 1a and supplies hydrogen to each cell 10, and an air inlet manifold 122a that communicates with the air inlet 1b and supplies air to each cell 10. Further, the separator 12 communicates with the hydrogen outlet 1c to discharge the hydrogen electrode side impurities from each cell 10, and communicates with the air outlet 1d to discharge the air electrode side impurities from each cell 10. An air outlet manifold 122b is formed.

  In the separator 12, a hydrogen flow path 123 for supplying hydrogen to the hydrogen electrode is formed on the surface of the pair of electrodes facing the hydrogen electrode, and an air flow for supplying air to the air electrode on the surface facing the air electrode. A path 124 is formed. The hydrogen flow path 123 communicates with the hydrogen inlet manifold 121a and the hydrogen outlet manifold 121b, and the air flow path 124 communicates with the air inlet manifold 122a and the air outlet manifold 122b.

  The separator 12 of this embodiment includes a hydrogen upstream portion (fuel gas upstream portion) on the upstream side of the hydrogen flow in the hydrogen passage 123 and an air downstream portion (oxidant gas downstream portion) on the downstream side of the air flow in the air passage 124. However, they are configured to face each other with the membrane electrode assembly 121 interposed therebetween. The separator 12 includes a hydrogen downstream portion (fuel gas downstream portion) on the downstream side of the hydrogen flow in the hydrogen passage 123 and an air upstream portion (oxidant gas upstream portion) on the upstream side of the air flow in the air passage 124. The membrane electrode assembly 11 is configured to face each other.

  More specifically, the hydrogen upstream portion is a portion closer to the hydrogen inlet manifold 121a than the hydrogen outlet manifold 121b of the hydrogen passage 123, and the hydrogen downstream portion is a hydrogen outlet manifold 121b than the hydrogen inlet manifold 121a of the hydrogen passage 123. It is a part close to. Further, the air upstream part is a part closer to the air inlet manifold 122a than the air outlet manifold 122b of the air flow path 124, and the air downstream part is closer to the air outlet manifold 122b than the air inlet manifold 122a of the air flow path 124. It is a part.

In each cell 10, hydrogen is supplied to the hydrogen electrode via the hydrogen flow path 123 of the separator 12, and oxygen-containing air is supplied to the air electrode via the air flow path 124, whereby the following electrochemical reaction is performed. Occurs and electrical energy is generated.
(Hydrogen electrode) H2 → 2H ++ 2e−
(Air electrode) 2H ++ 1 / 2O2 + 2e− → H2O
And the electric current obtained by generating electric power in each cell 10 is collected by the current collection board 10a provided in the both ends of the laminated | stacked cell 10, and is supplied to the electrical load 4 (refer FIG. 1).

  Here, the flow of current flowing inside the fuel cell 1 is generally viewed from the stacking direction of the cells 10 (the current collector plate on the front side of the fuel cell 1 shown in FIG. 1 faces the current collector plate on the back side). Direction). Therefore, a magnetic field (line of magnetic force) is formed by the current flowing through the fuel cell 1 so as to surround the outer periphery of the fuel cell 1 as shown in FIG. As shown in FIG. 3, when current flows from the front side in the stacking direction of the cells 10 toward the back side, the direction of the magnetic flux of the fuel cell 1 is clockwise when viewed from the front side in the stacking direction of the cells 10. Direction. Since this magnetic field corresponds to a change in the current flowing through the fuel cell 1, the flow of the current flowing through the fuel cell 1 can be grasped by detecting the strength of the magnetic field. FIG. 3 is an explanatory diagram for explaining a magnetic field formed in the outer periphery of the fuel cell.

  Next, the fuel cell diagnostic device 5 that diagnoses the power generation state of the fuel cell 1 will be described. As shown in FIG. 1, the fuel cell diagnostic device 5 diagnoses the power generation state of the fuel cell 1 based on the voltage sensor 51, the current sensor 52, the pair of magnetic sensors 53 and 54, and the output signals of the sensors 51 to 54. The control device 50 and the like are configured.

  The voltage sensor 51 constitutes voltage detecting means for detecting a potential difference (output voltage of the fuel cell 1) between the current collector plates 10a, and the current sensor 52 is a current (output from the current collector plate 10a to the electric load 4 ( Current detection means for detecting the output current of the fuel cell 1) is configured. The control device 50 receives the voltage signal detected by the voltage sensor 51 and the current signal detected by the current sensor 52, and calculates the internal resistance inside the fuel cell based on these signals.

  The pair of magnetic sensors 53 and 54 are arranged at positions shifted in the circumferential direction around the outer periphery of the predetermined cell 10 among the plurality of cells 10 and detect the strength of the magnetic field formed around the outer periphery of the predetermined cell 10. A pair of magnetic field detecting means is configured. As the magnetic sensors 53 and 54, Hall elements can be used.

  One magnetic sensor (hereinafter referred to as a first magnetic sensor) 53 of the pair of magnetic sensors 53 and 54 has a magnetic field strength formed by a current flowing in the hydrogen upstream portion and the air downstream portion in the cell plane. It is to detect. The first magnetic sensor 53 is arranged at a position closer to the hydrogen upstream portion and the air downstream portion than the hydrogen downstream portion and the air upstream portion in the cell surface on the outer periphery of the predetermined cell 10 (see FIG. 2). The positions near the hydrogen upstream portion and the air downstream portion on the outer periphery of the cell 10 are the hydrogen inlet manifold 121a and the air outlet manifold 122b in the cell 10 surface of the outer peripheral wall surface (side surface parallel to the cell stacking direction) of the cell 10. It is also a position close to the position where is formed.

  The other magnetic sensor 54 (hereinafter referred to as the second magnetic sensor) detects the strength of the magnetic field formed by the current flowing through the hydrogen downstream site and the air upstream site in the cell plane. The second magnetic sensor 54 is arranged at a position facing the position where the first magnetic sensor 53 is arranged with the cell 10 in between. That is, the second magnetic sensor 54 is disposed at a position closer to the hydrogen downstream site and the air upstream site than the hydrogen upstream site and the air downstream site in the cell surface on the outer periphery of the predetermined cell 10 (see FIG. 2). The position near the hydrogen downstream part and the air upstream part on the outer periphery of the cell 10 is also a position near the position where the hydrogen outlet manifold 121b and the air inlet manifold 122a in the cell 10 surface are formed on the outer peripheral wall surface of the cell 10. .

  Further, first and second magnetic current collectors 531 and 541 are arranged adjacent to the magnetic sensors 53 and 54, respectively. The current collectors 531 and 541 can be made of permalloy (magnetic material) with relatively little residual magnetism.

  Each of the magnetic collectors 531 and 541 is for collecting the magnetic field formed around the outer periphery of the plurality of cells 10 in each of the first and second magnetic sensors 53 and 54. The shape extends along the direction. Specifically, as shown in FIG. 4, the first and second current collectors 531 and 541 have a length L in the stacking direction of the cells 10 larger than a thickness T of the single cell (thickness in the stacking direction of the cells). It is formed in the shape of a long long plate.

  In FIG. 4, the length L in the stacking direction of the cells 10 of each of the current collectors 531 and 541 is set to the thickness of three single cells 10. In this case, the first and second magnetic sensors 53 and 54 can collectively detect the strength of the magnetic field formed around the outer periphery of the three cells 10. FIG. 4 is an explanatory diagram for explaining the length of the magnetic current collectors 531 and 541 in the stacking direction of the cells 10, and the stacked cells 10 in the fuel cell 1 are viewed from a direction orthogonal to the stacking direction of the cells 10. It shows the state as seen.

  Returning to FIG. 1, the first magnetic flux collector 531 includes a pair of magnetic flux collectors 531 a and 531 b arranged so as to sandwich the first magnetic sensor 53, and the second magnetic flux collector 541 includes the second magnetic flux collector 541. It is composed of a pair of magnetic flux collectors 541a and 541b arranged so as to sandwich the sensor 54.

  One of the magnetic flux collectors 531a and 531b of the first magnetic flux collector 531 is disposed on the outer periphery closer to the hydrogen upstream portion than the air downstream portion of the cell 10, and the other magnetic flux collector 531b It is arrange | positioned at the outer periphery nearer the downstream air part than the upstream hydrogen part.

  The pair of magnetism collecting portions 531 a and 531 b are formed in a symmetrical shape with respect to the first magnetic sensor 53. In addition, each magnetism collecting part 531a, 531b protrudes toward the first magnetic sensor 53 at a position closest to the first magnetic sensor 53, and contacts the first magnetic sensor 53 at the protruding position.

  In addition, one of the magnetism collecting parts 541a and 541b of the second magnetism collecting body 541 is disposed on the outer periphery closer to the air upstream part than the hydrogen downstream part of the cell 10, and the other magnetism collecting part 541b is The cell 10 is disposed on the outer periphery closer to the hydrogen downstream portion than the air upstream portion.

  The pair of magnetism collecting portions 541 a and 541 b are formed in a symmetrical shape with respect to the second magnetic sensor 54. In addition, each magnetism collection part 541a, 541b protrudes toward the 2nd magnetic sensor 54 in the part nearest to the 2nd magnetic sensor 54, and is contacting the 2nd magnetic sensor 54 in this protruding part.

  By collecting the magnetic fields around the outer circumferences of the plurality of cells 10 to the magnetic sensors 53 and 54 by using the first and second magnetic current collectors 531 and 541, the magnetic sensors 53 and 54 each have a circumference around the predetermined cell 10. However, the strength of the magnetic field formed around the outer periphery of the plurality of cells 10 can be detected.

  The control device 50 of the fuel cell diagnostic device 5 constitutes diagnostic means for diagnosing the power generation state of the fuel cell 1. The control device 50 is configured by a known microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and executes processing such as various calculations according to a program stored in the ROM.

  The voltage sensor 51, the current sensor 52, the pair of magnetic sensors 53, 54, and the like are connected to the input side of the control device 50. In the control device 50 of the present embodiment, calculation processing for calculating the internal resistance of the fuel cell 1 is performed based on the voltage signal from the voltage sensor 51 and the current signal from the current sensor 52. In addition, based on the magnetic signals from the first and second magnetic sensors 53 and 54, a calculation process for calculating the magnetic force difference between the magnetic fields formed in the outer periphery of the fuel cell 1 corresponding to the current bias in the fuel cell 1 It is carried out. Therefore, the control device 50 of the present embodiment constitutes a part of the resistance measurement unit that measures the internal resistance of the fuel cell 1 and also calculates the current bias calculation unit that calculates the current bias in the cell plane in the plurality of cells 10. Is configured.

  Further, a hydrogen pressure regulating valve, a solenoid valve, an air pump, an air pressure regulating valve, and the like are connected to the output side of the control device 50, and a control signal is output to each connected device.

  Next, a method for diagnosing the power generation state of the fuel cell 1 using the fuel cell diagnostic device 5 having the above configuration will be described with reference to FIG. FIG. 5 shows a diagnosis process of the power generation state of the fuel cell 1 executed by the control device 50. The control device 50 executes diagnostic processing during power generation (during operation) of the fuel cell 1.

  First, in step S1, detection signals detected by the voltage sensor 51, the current sensor 52, the pair of magnetic sensors 53, 54, and the like are read.

  Next, the process proceeds to step S2, and the internal resistance R inside the fuel cell 1 is calculated based on the detection signals of the voltage sensor 51 and the current sensor 52 read in step S1. Here, when the wet state inside the fuel cell 1 becomes a dry state (dry up), the resistance of the electrolyte membrane of the membrane electrode assembly 11 increases, so the internal resistance R of the entire fuel cell 1 increases. That is, it is possible to determine whether or not the inside of the fuel cell is in a dry state based on the magnitude of the internal resistance R of the fuel cell 1.

  Therefore, in step S3, it is determined based on the internal resistance R of the fuel cell 1 whether or not the inside of the fuel cell 1 is in a dry state. Specifically, when the internal resistance R (measured value) calculated in step S3 is equal to or greater than a preset resistance value (step S3: YES), the process proceeds to step S4, and the inside of the fuel cell 1 is dry. Diagnose the condition.

  If it is diagnosed that the inside of the fuel cell 1 is dry, the humidity in the fuel cell 1 is increased by reducing the load on the fuel cell 1 and lowering the temperature inside the fuel cell 1. Thereby, the state where the inside of fuel cell 1 is dried can be eliminated. Further, when a humidifier is provided in the air supply pipe 3a, the humidification amount of the air supplied by the humidifier may be increased.

  If the internal resistance R calculated in step S3 is not equal to or greater than the set resistance value (step S3: NO), the process proceeds to step S5. In step S5, it is determined whether or not the amount of hydrogen supplied to each cell 10 is insufficient, that is, whether or not hydrogen is insufficient.

  Here, the short supply amount of hydrogen is more likely to occur near the hydrogen outlet manifold 121b than on the hydrogen inlet manifold 121a side. In other words, the short supply amount of hydrogen is more likely to occur on the hydrogen downstream side than the hydrogen upstream portion in the cell plane.

  Therefore, when a shortage of hydrogen supply occurs, a current bias occurs such that the current generated at the hydrogen downstream site in the cell plane is lower than the current flowing through the hydrogen upstream site. Due to this current bias, the magnetic force formed on the outer periphery corresponding to the hydrogen downstream portion of the cell 10 becomes smaller than the magnetic force formed on the outer periphery corresponding to the hydrogen upstream portion of the cell 10. Specifically, the detection value of the second magnetic sensor 54 is lower than the detection value of the first magnetic sensor 53.

  Therefore, the shortage of hydrogen supply (hydrogen deficiency) is caused by the difference between the magnetic force formed on the outer periphery corresponding to the hydrogen downstream portion of the cell 10 and the magnetic force formed on the outer periphery corresponding to the hydrogen upstream portion of the cell 10. Can be determined based on

  Therefore, specifically, in step S5, the magnetic force difference corresponding to the current bias is calculated by subtracting the detection value of the second magnetic sensor 54 from the detection value of the first magnetic sensor 53 read in step S1. It is determined whether or not the magnetic force difference is greater than or equal to a preset first set value. When the calculated magnetic force difference is equal to or larger than the first set value set in advance, that is, when it is determined that the supply amount of hydrogen is insufficient (step S5: YES), the process proceeds to step S6, and the supply amount of hydrogen Diagnose that is missing. Here, the first set value is set in advance based on an experiment or a simulation result using a physical model.

  In addition, when it is diagnosed that the supply amount of hydrogen is insufficient, the supply amount of hydrogen is insufficient by increasing the supply amount of hydrogen to the fuel cell 1, for example, by increasing the opening of the hydrogen pressure regulating valve. Can be eliminated.

  When the magnetic force difference calculated in step S5 is not equal to or greater than the first set value, that is, when it is determined that the supply amount of hydrogen is not insufficient (step S5: NO), the process proceeds to step S7. In step S7, it is determined whether or not the amount of air supplied to each cell 10 is insufficient, that is, whether or not the air is insufficient. Note that the shortage of air supply includes not only the case where the amount of air supplied from the outside is small, but also the case where the generated water becomes excessive and air cannot be supplied to the air electrode (flooding). .

  Here, the shortage of air supply is more likely to occur near the air outlet manifold 122b than on the air inlet manifold 122a side. In other words, the shortage of air supply is more likely to occur on the air downstream side than the air upstream portion in the cell plane.

  For this reason, when the supply amount of air is insufficient, a current is biased such that the current generated in the air downstream portion in the cell plane is lower than the current flowing in the air upstream portion. Due to this current bias, the magnetic force formed on the outer periphery corresponding to the air downstream portion of the cell 10 becomes smaller than the magnetic force formed on the outer periphery corresponding to the air upstream portion of the cell 10. Specifically, the detection value of the first magnetic sensor 53 is lower than the detection value of the second magnetic sensor 54.

  Therefore, the shortage of the air supply amount is determined based on the magnetic force difference between the magnetic force formed on the outer periphery corresponding to the air downstream portion of the cell 10 and the magnetic force formed on the outer periphery corresponding to the air upstream portion of the cell 10. Can do.

  For this reason, specifically, in step S7, the magnetic force difference corresponding to the current bias is calculated by subtracting the detection value of the first magnetic sensor 53 from the detection value of the second magnetic sensor 54, and the calculated magnetic force difference is preset. It is determined whether or not the second set value is exceeded. When the calculated magnetic difference is equal to or greater than the second set value, that is, when it is determined that the air supply amount is insufficient (step S7: YES), the process proceeds to step S8, and the air supply amount is insufficient. Diagnose that Here, the second set value is set in advance based on an experiment or a simulation result using a physical model.

  When it is diagnosed that the supply amount of air is insufficient, the supply amount of air to the fuel cell 1 is increased by adjusting the rotation speed of the air pump or the opening of the air pressure regulating valve. Insufficient supply of air can be resolved.

  If the magnetic force difference calculated in step S7 is not equal to or greater than the second set value, that is, if it is determined that the supply amount of air is not insufficient (step S7: NO), the power generation state of the fuel cell 1 is normal. Since it is in a state, the diagnosis process is terminated.

  According to the present embodiment described above, the magnetic force difference in the plurality of cells 10 is calculated by the pair of magnetic sensors 53 and 54 arranged around the outer periphery of the cell 10, and the power generation state of the fuel cell 1 is determined based on the calculation result. Can be diagnosed.

  And each structure of the fuel cell diagnostic apparatus 5 of this embodiment is a structure provided in the exterior of the fuel cell 1, and since it does not become resistance at the time of the power generation of the fuel cell 1, it has a bad influence on the power generation performance of the fuel cell 1. The power generation state of the fuel cell 1 can be diagnosed.

  Here, when it is the structure which arrange | positions the electrically-conductive member which incorporated the magnetic sensor between the cells 10 like the past, and diagnoses the electric power generation state of the fuel cell 1, when diagnosing the electric power generation state of the some cell 10, It is necessary to dispose a conductive member between the cells 10, which is complicated by an increase in the number of conductive plates.

  However, the configuration of the present embodiment is a configuration in which a magnetic field formed on the outer periphery of the plurality of cells 10 by the pair of magnetic collectors 531 and 541 is collected in the pair of magnetic sensors 53 and 54. The pair of magnetic sensors 53 and 54 can collectively detect the strength of the magnetic field formed on the.

  Therefore, even when diagnosing the power generation state of the plurality of cells 10, the power generation state of the fuel cell 1 can be diagnosed without adding a configuration such as a sensor. The power generation state of the cell 10 can be diagnosed.

  Furthermore, according to the configuration of the present embodiment, the configuration using the pair of magnetic sensors 53 and 54 can diagnose the shortage of the hydrogen supply amount and the air supply amount of the fuel cell 1, and thus a simpler configuration. Thus, the power generation state of the fuel cell 1 can be diagnosed.

  Furthermore, in this embodiment, since the difference (magnetic difference) between the detection values of the pair of magnetic sensors 53 and 54 is used for diagnosis of the shortage of the hydrogen supply amount and the shortage of the air supply amount, Similarly, added noise can be removed. Therefore, it is possible to improve the diagnostic accuracy of the power generation state of the fuel cell 1.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. Parts that are the same as or equivalent to those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted. Here, FIG. 6 is a schematic perspective view showing the fuel cell and the fuel cell diagnostic apparatus according to the present embodiment.

  The fuel cell diagnostic device 5 of the present embodiment is different from the fuel cell diagnostic device 5 described in the first embodiment in the shape of the pair of magnetic current collectors 531 and 541. That is, as shown in FIG. 2, the pair of magnetic collectors 531 and 541 of the present embodiment has the magnetic collectors 531a, 531b, 541a, and 541b in an L shape.

  In this embodiment, each magnetism collection part 531a, 531b, 541a, 541b surrounds each manifold 121a, 121b, 122a, 122b which each magnetism collection part 531a, 531b, 541a, 541b respond | corresponds by making it L-shaped. Are arranged as follows.

  Specifically, the magnetic flux collector 531a of the first magnetic flux collector 531 is disposed so as to surround the outer periphery of the cell 10 near the hydrogen inlet manifold 121a, and the magnetic flux collector 531b of the first magnetic flux collector 531 is disposed in the cell 10. It arrange | positions so that the outer periphery near the air outlet manifold 122b may be enclosed.

  Further, the magnetism collecting part 541a of the second magnetism collecting body 541 is disposed so as to surround the outer periphery of the cell 10 near the air inlet manifold 122a, and the magnetism collecting part 541b of the second magnetism collecting body 541 is disposed in the hydrogen outlet manifold of the cell 10. It arrange | positions so that the outer periphery near 121b may be enclosed.

  Thereby, in each magnetism collection part 531a, 531b, 541a, 541b, the magnetic field formed in the position close | similar to each corresponding manifold 121a, 121b, 122a, 122b can be collected in the magnetic sensor 53,54. As a result, it is possible to more appropriately detect a magnetic force difference caused by a shortage of hydrogen supply and a shortage of air supply.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. Parts that are the same as or equivalent to those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted. Here, FIG. 7 is a schematic perspective view showing the fuel cell and the fuel cell diagnostic apparatus according to the present embodiment.

  In the first embodiment described above, a pair of magnetic sensors 53 and 54 are arranged on the outer periphery of the predetermined cell 10 of the fuel cell 1. In the present embodiment, the predetermined cell 10 of the fuel cell 1 is disposed. Two sets of a pair of magnetic sensors 53 and 54 are arranged on the outer periphery.

  Of the pair of magnetic sensors 53, 54, the first pair of magnetic sensors 53 a, 54 a are disposed on the outer periphery of the cell 10 at positions close to the hydrogen inlet manifold 121 a and the hydrogen outlet manifold 121 b. Therefore, based on the detection values of the first pair of magnetic sensors 53a and 54a, it is possible to grasp the current bias in the hydrogen upstream portion and the hydrogen downstream portion of the cell 10.

  Further, the second pair of magnetic sensors 53b and 54b are disposed on the outer periphery of the cell 10 at positions close to the air inlet manifold 122a and the air outlet manifold 122b. Therefore, it is possible to grasp the current bias between the air upstream portion and the air downstream portion of the cell 10 based on the detection values of the second pair of magnetic sensors 53b and 54b.

  The magnetic sensors 53a, 53b, 54a, and 54b are connected to the pair of magnetic collectors 532, 533, 542, and 543, respectively, and are formed at positions near the manifolds 121a, 121b, 122a, and 122b on the outer periphery of the cell 10. Magnetic field is collected.

  Thus, when it is set as the structure which provides the four magnetic sensors 53a, 53b, 54a, 54b, the bias of the electric current of the hydrogen upstream site | part of the cell 10 and a hydrogen downstream site | part, and the air upstream site | part and air downstream site | part of the cell 10 Can be grasped independently. That is, as in the first embodiment, the hydrogen upstream portion and the air downstream portion in each gas flow path 123, 124 formed in the separator 12 face each other, and the hydrogen downstream portion and the air upstream portion face each other. Even if not, it is possible to grasp the current bias in each part.

  Therefore, in the fuel cell diagnostic device of the present embodiment, it is possible to diagnose the power generation state of the plurality of cells 10 without depending on the structure of the gas flow paths 123 and 124 of the cells 10 of the fuel cell 1.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described mainly based on FIGS. The same or equivalent parts as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted or simplified. Here, FIG. 8 is an explanatory diagram for explaining the geomagnetism formed around the fuel cell 1, and FIG. 9 is a diagnosis process of the power generation state of the fuel cell 1 executed by the control device 50 of the present embodiment. Show.

  Here, in addition to the magnetic field due to the current that flows when the fuel cell 1 generates power, a magnetic field due to geomagnetism is formed around the fuel cell 1. As indicated by the solid line arrow in FIG. 8, this geomagnetic magnetic flux is in one specific direction with respect to the fuel cell 1 (the right direction in the drawing in FIG. 8). When the fuel cell 1 is applied to an in-vehicle power generation system, the direction of the geomagnetic flux with respect to the fuel cell 1 changes as the vehicle moves.

  When the strength of the magnetic field due to the current flowing during the power generation of the fuel cell 1 is not sufficiently large compared to the strength of the magnetic field due to geomagnetism, the influence of geomagnetism cannot be ignored, and the first magnetic sensor 53 and the second magnetic sensor 54. There is a possibility that the fuel cell 1 cannot be properly diagnosed based on the detected value.

  Therefore, an object of the present embodiment is to provide a fuel cell diagnostic device 5 that can appropriately diagnose the fuel cell 1 while eliminating the influence of geomagnetism.

  The basic configuration of the fuel cell diagnostic device 5 of this embodiment is the same as that of the first embodiment. The configuration of the present embodiment will be briefly described. The first magnetic sensor 53 and the second magnetic sensor 54 of the present embodiment are shifted by a half circumference (for example, about 160 ° to 200 °) in the circumferential direction around the outer periphery of the cell 10. Placed in position. In other words, the first magnetic sensor 53 and the second magnetic sensor 54 are arranged at positions facing each other across the cell 10 in a direction orthogonal to the stacking direction of the cells 10 (see FIG. 8).

  Therefore, the direction of the magnetic flux generated in the outer periphery of the fuel cell 1 by the current flowing in the fuel cell 1 is opposite between the periphery of the first magnetic sensor 53 and the periphery of the second magnetic sensor 54. That is, in FIG. 8, when the direction of the magnetic flux generated in the outer periphery of the fuel cell 1 by the current flowing in the fuel cell 1 is the clockwise direction around the outer periphery of the fuel cell 1 (see the broken line arrow in FIG. 8), The direction of the magnetic flux around the first magnetic sensor 53 is the right direction of the paper (see the white broken arrow above the paper surface), whereas the direction of the magnetic flux around the second magnetic sensor 54 is the left direction of the paper (lower the paper surface). (See the white dashed arrow).

  On the other hand, the direction of the geomagnetic flux is a specific direction with respect to the fuel cell 1. For example, when the direction of the geomagnetic flux is the direction indicated by the solid line arrow in FIG. 8, the direction of the magnetic flux around the first magnetic sensor 53 and the second magnetic sensor 54 is the right direction on the page.

  Each of the first magnetic sensor 53 and the second magnetic sensor 54 detects positively the strength of the magnetic field that is in the same direction as the direction of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1. Has been placed. Therefore, the first magnetic sensor 53 and the second magnetic sensor 54 output the strength of the magnetic field generated by the current flowing through the fuel cell 1 to the control device 50 as a positive value.

  On the other hand, since the direction of the magnetic flux of the geomagnetism is a specific direction with respect to the fuel cell 1, the first magnetic sensor 53 and the second magnetic sensor 54 have the magnetic field strength caused by the geomagnetism positive by one magnetic sensor. The value is output to the control device 50 as a negative value by the other magnetic sensor.

  For example, under the condition that the direction of the magnetic flux of the geomagnetism is the right direction in FIG. 8, the strength of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1 is φ (≧ 0), and the magnetic field due to the geomagnetism. Is φe (≧ 0), the detection value Va detected by the first magnetic sensor 53 is φ + φe, and the detection value Vb detected by the second magnetic sensor 54 is φ−φe.

  Therefore, by adding the detection values of the first magnetic sensor 53 and the second magnetic sensor 54 together, the strength of the magnetic field due to geomagnetism contained in the detection value Va of the first magnetic sensor 53 and the detection of the second magnetic sensor 54 are detected. It is possible to cancel the strength of the magnetic field due to the geomagnetism included in the value Vb.

  Thereby, the influence of the magnetic field by geomagnetism can be excluded from the magnetic field formed on the outer periphery of the fuel cell 1. Note that the total value V obtained by adding the detection values of the first magnetic sensor 53 and the second magnetic sensor 54 is V = (φ + φe) + (φ−φe) = 2φ.

  Next, a method for diagnosing the power generation state of the fuel cell 1 using the fuel cell diagnostic device 5 having the above configuration will be described with reference to FIG.

  In this embodiment, when it is determined that the internal resistance R is not equal to or greater than the set resistance value in the determination process of step S3 (step S3: NO), the detection value Va of the first magnetic sensor 53 and the second magnetic sensor 54 are determined. The presence or absence of abnormality of the fuel cell 1 is determined based on the sum value with the detected value Vb (step S9).

  Specifically, in step S9, the detected value Va of the first magnetic sensor 53 and the detected value Vb of the second magnetic sensor 54 are added together, and the fuel cell 1 is generated by the current flowing through the fuel cell 1 excluding the influence of geomagnetism. Detect the strength of the magnetic field formed around the outside of the.

  The sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is the intensity of the magnetic field formed around the outer periphery of the fuel cell 1 when the output of the fuel cell 1 is normal. It becomes about twice. Therefore, based on the current signal from the current sensor 52 and the like, the strength of the magnetic field formed around the outer periphery of the fuel cell 1 when the output of the fuel cell 1 is normal is estimated, and the estimated value is For example, a value obtained by multiplying 1.8 to 1.9 is set as the first reference value.

  Then, it is determined whether or not the sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is smaller than a preset first reference value.

  As a result, if it is determined that the sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is smaller than the first reference value, some abnormality occurs in the fuel cell 1. Therefore, it is determined that there is an abnormality in the fuel cell 1 (step S9: YES).

  On the other hand, when it is determined that the sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is larger than the first reference value, it is determined that there is no abnormality in the fuel cell 1 ( Step S9: NO).

  If it is determined in step S9 that the fuel cell 1 is abnormal (step S9: YES), the process proceeds to step S5, and the hydrogen supply amount of the fuel cell 1 is insufficient. It is determined whether or not.

  If it is determined in step S9 that there is no abnormality in the fuel cell 1 (step S9: NO), it is determined that there is no abnormality in the fuel cell 1, and the diagnosis process is terminated.

  According to the configuration of the present embodiment described above, the first magnetic sensor that eliminates the influence of geomagnetism when the sum of the detection values in the pair of magnetic field detection means (53, 54) that excludes the influence of geomagnetism is low. When the combined value of the detected values of 53 and the second magnetic sensor 54 is lower than the first reference value, the power generation state of the fuel cell 1 such as insufficient supply of hydrogen or air to the fuel cell 1 is diagnosed. Even if the strength of the magnetic field due to the current flowing through the battery 1 is not sufficiently large compared to the strength of the magnetic field due to geomagnetism, the power generation state of the fuel cell 1 based on the first magnetic sensor 53 and the second magnetic sensor 54 Can be diagnosed appropriately.

  Here, in this embodiment, each of the first magnetic sensor 53 and the second magnetic sensor 54 has a magnetic field strength that is in the same direction as the direction of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1. Although it arrange | positions so that it may detect as positive, it is not limited to this.

  For example, each of the first magnetic sensor 53 and the second magnetic sensor 54 detects the strength of the magnetic field that is in the same direction as the direction of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1 as negative. It is good also as a form to arrange.

  In this case, the first magnetic sensor 53 and the second magnetic sensor 54 output the intensity of the magnetic field generated by the current flowing through the fuel cell 1 to the control device 50 as a negative value. Since the direction of the magnetic flux of the geomagnetism is a specific direction with respect to the fuel cell 1, in the first magnetic sensor 53 and the second magnetic sensor 54, the strength of the magnetic field due to the geomagnetism is a positive value by one magnetic sensor, The other magnetic sensor outputs a negative value to the control device 50.

  For example, under the condition that the direction of the magnetic flux of geomagnetism is the right direction in the drawing in FIG. Is φe (≧ 0), the detection value Va detected by the first magnetic sensor 53 is −φ−φe, and the detection value Vb detected by the second magnetic sensor 54 is −φ + φe.

  Therefore, by adding the detection values of the first magnetic sensor 53 and the second magnetic sensor 54 together, the strength of the magnetic field due to geomagnetism contained in the detection value Va of the first magnetic sensor 53 and the detection value of the second magnetic sensor 54 are calculated. It is possible to cancel the strength of the magnetic field due to the geomagnetism contained in Vb. The sum V obtained by adding the detection values of the first magnetic sensor 53 and the second magnetic sensor 54 is V = (− φ−φe) + (− φ + φe) = − 2φ.

  Further, the sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 becomes a negative value. For this reason, in the determination process of step S9, the second reference value in which the sum of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is changed to a negative value. It may be determined whether or not the fuel cell 1 is greater than the value, and if it is greater than the second reference value, it may be determined that the fuel cell 1 is abnormal.

  As another form, the first magnetic sensor 53 is arranged so as to detect positively the strength of the magnetic field that is in the same direction as the direction of the magnetic field generated around the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1. The two magnetic sensor 54 may be arranged so as to detect as negative the strength of the magnetic field that is in the same direction as the direction of the magnetic field generated around the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1.

  In this case, the first magnetic sensor 53 outputs the strength of the magnetic field generated by the current flowing through the fuel cell 1 as a positive value to the control device 50, and the second magnetic sensor 54 outputs the magnetic field generated by the current flowing through the fuel cell 1. Is output to the control device 50 as a negative value. Since the direction of the magnetic flux of the geomagnetism is a specific direction with respect to the fuel cell 1, the first magnetic sensor 53 and the second magnetic sensor 54 indicate the strength of the magnetic field due to geomagnetism with the same sign (positive value or (Negative value) is output to the control device 50.

  For example, under the condition that the direction of the magnetic flux of geomagnetism is the right direction in the drawing in FIG. Is φe (≧ 0), the detection value Va detected by the first magnetic sensor 53 is φ + φe, and the detection value Vb detected by the second magnetic sensor 54 is −φ + φe.

  Accordingly, by subtracting the detection value of the second magnetic sensor 54 from the detection value of the first magnetic sensor 53, the strength of the magnetic field due to the geomagnetism contained in the detection value Va of the first magnetic sensor 53, and the second magnetic sensor 54 It is possible to cancel out the strength of the magnetic field due to geomagnetism contained in the detection value Vb. A subtraction value V obtained by subtracting the second magnetic sensor 54 from the detection value of the first magnetic sensor 53 is V = (φ + φe) − (− φ + φe) = 2φ.

  Further, since the subtraction value of the detection value Va of the first magnetic sensor 53 and the detection value Vb of the second magnetic sensor 54 is a positive value, in the determination process of step S9, the detection value Va of the first magnetic sensor 53 and the first value 2 It is determined whether or not the subtraction value of the detection value Vb of the magnetic sensor 54 is smaller than a third reference value set to the same value as the first reference value, and if smaller than the third reference value, What is necessary is just to determine with the fuel cell 1 having abnormality.

  Further, the first magnetic sensor 53 is arranged so as to detect as negative the strength of the magnetic field that is in the same direction as the direction of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1. 54 may be arranged so as to detect the strength of the magnetic field in the same direction as the direction of the magnetic field generated in the outer periphery of the fuel cell 1 by the current flowing through the fuel cell 1 as positive.

  In this case, by subtracting the detection value of the first magnetic sensor 53 from the detection value of the second magnetic sensor 54, the strength of the magnetic field due to geomagnetism contained in the detection value Va of the first magnetic sensor 53, and the second magnetic sensor. The strength of the magnetic field due to the geomagnetism contained in the detection value Vb of the sensor 54 can be canceled out.

  These modifications can also cancel the strength of the magnetic field due to geomagnetism, and the power generation state of the fuel cell 1 can be appropriately diagnosed based on the first magnetic sensor 53 and the second magnetic sensor 54.

  In this embodiment, the basic configuration of the fuel cell diagnostic device 5 is the same as that of the first embodiment. However, the basic configuration of the fuel cell diagnostic device 5 is not limited to this, for example, the second embodiment. Alternatively, the configuration may be the same as that of the third embodiment.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, this invention is not limited to this, Unless it deviates from the range described in each claim, it is not limited to the wording of each claim, and those skilled in the art Improvements based on the knowledge that a person skilled in the art normally has can be added as appropriate to the extent that they can be easily replaced. For example, various modifications are possible as follows.

  (1) In the above-described embodiment, the example in which the length L in the stacking direction of the cells 10 of each of the current collectors 531 and 541 is set to the thickness of three single cells has been described with reference to FIG. Not. The length L of each of the current collectors 531 and 541 in the stacking direction of the cells 10 may be equal to or greater than the thickness of the single cell 10. For example, the length L may be the same as the length of the cells 10 of the fuel cell 1 in the stacking direction. Good.

  (2) In the diagnosis process (see FIG. 4) of the power generation state of the fuel cell 1 of the above-described embodiment, the air supply amount is determined to be insufficient after the hydrogen supply amount is determined to be insufficient. It is not limited to this. That is, in the diagnosis process, after determining the shortage of the air supply amount, the shortage of the hydrogen supply amount may be determined.

  (3) In the above-described embodiment, the example in which the magnetic sensor is configured by the Hall element has been described. However, the present invention is not limited thereto, and for example, an MI element, an AMR element, an MR element, a flux gate, or the like may be used. .

  (4) In the above-described embodiment, the example in which the current collector is made of permalloy (magnetic material) has been described. However, the present invention is not limited to this. Good.

  (5) In the above-described embodiment, the example in which the polymer electrolyte fuel cell (PEMFC) is used as the fuel cell 1 has been described. However, the present invention is not limited to this. For example, a phosphoric acid fuel cell (PAFC), a solid oxide fuel cell (SOFC), an alkaline fuel cell (AFC), or the like may be used as the fuel cell 1.

  (6) Further, the fuel cell 1 can be applied to an in-vehicle power generation system of a fuel cell vehicle, a power generation system mounted on another moving body (such as a ship or an airplane), a stationary power generation system, and the like.

1 Fuel cell 10 cells (power generation cell)
121a Hydrogen inlet manifold (fuel gas inlet)
121b Hydrogen outlet manifold (fuel gas outlet)
122a Air inlet manifold (oxidant gas inlet)
122b Air outlet manifold (oxidant gas outlet)
51 Voltage sensor (part of resistance measuring means)
52 Current sensor (part of resistance measurement means)
53 1st magnetic sensor (one magnetic field detection means)
531 Magnetic collector 54 Second magnetic sensor (the other magnetic field detecting means)
541 Magnetic current collector 50 Control device (diagnostic means)

Claims (9)

A fuel cell diagnostic device for diagnosing a power generation state of a fuel cell (1) in which a plurality of power generation cells (10) that generate electricity by causing an electrochemical reaction between an oxidant gas and a fuel gas,
It is arranged at a position shifted in the circumferential direction around the outer periphery of the power generation cell (10), and detects the strength of the magnetic field formed in the outer periphery of the fuel cell (1) by the current flowing in the fuel cell (1). A pair of magnetic field detection means (53, 54),
An outer periphery of the fuel cell (1) is disposed adjacent to the magnetic field detection means (53, 54), extends along the stacking direction of the plurality of power generation cells (10), and the plurality of power generation cells (10). A magnetic current collector (531, 541) that collects the magnetic field formed around the outer periphery of the magnetic field detection means (53, 54);
Diagnostic means (50) for diagnosing the power generation state of the fuel cell (1) based on the detection values detected by the pair of magnetic field detection means (53, 54);
A fuel cell diagnostic apparatus comprising:   2. The magnetic current collector (531, 541) has a length (L) in the stacking direction that is longer than a thickness (T) in the stacking direction of the power generation cell (10). Fuel cell diagnostic device. The power generation cell (10) has a fuel gas upstream portion closer to the inlet (121a) than the fuel gas outlet (121b) in the cell plane, and an oxidation closer to the outlet (122b) than the inlet (122a) of the oxidant gas. The downstream portion of the oxidant gas faces the stacking direction, and the downstream portion of the fuel gas closer to the outlet (121b) than the inlet (121a) of the fuel gas in the cell surface and the inlet (122a) of the oxidant gas outlet (122b). ) And an upstream portion of the oxidant gas close to the stacking direction.
The pair of magnetic field detection means (53, 54) is arranged such that one of the magnetic field detection means (53) is close to the fuel gas upstream part and the oxidant gas downstream part on the outer periphery of the power generation cell (10), The other magnetic field detection means (54) is disposed at a position near the fuel gas downstream part and the oxidant gas upstream part on the outer periphery of the power generation cell (10),
The diagnosis means (50) is configured such that the detection value of the other magnetic field detection means (54) is decreased by a predetermined first set value or more with respect to the detection value of the one magnetic field detection means (53). And the detected value of the one magnetic field detecting means (53) is decreased by a predetermined second set value or more with respect to the detected value of the other magnetic field detecting means (54). 3. The fuel cell diagnostic apparatus according to claim 1 or 2, wherein a diagnosis is made that the oxidant gas is deficient when the fuel cell is running. The pair of magnetic field detection means (53a, 54a)
One magnetic field detection means (53a) is disposed at a position near the fuel gas upstream portion closer to the inlet (121a) than the fuel gas outlet (121b) in the cell surface on the outer periphery of the power generation cell (10),
The other magnetic field detection means (54a) is disposed at a position near the fuel gas downstream portion closer to the outlet (121b) than the fuel gas inlet (121a) in the cell surface on the outer periphery of the power generation cell (10),
The diagnosis means (50) is configured such that the detection value of the other magnetic field detection means (54a) is decreased by a predetermined first set value or more with respect to the detection value of the one magnetic field detection means (53a). 3. The fuel cell diagnostic apparatus according to claim 1, wherein the fuel cell is diagnosed as being deficient in fuel gas. The pair of magnetic field detection means (53b, 54b)
One magnetic field detection means (53b) is disposed at a position closer to the oxidant gas downstream part closer to the outlet (122b) than the oxidant gas inlet (122a) in the cell surface on the outer periphery of the power generation cell (10),
The other magnetic field detection means (54b) is disposed at a position near the oxidant gas downstream portion closer to the inlet (122a) than the oxidant gas outlet (122b) in the cell surface on the outer periphery of the power generation cell (10). And
The diagnosis means (50) is configured such that the detection value of the one magnetic field detection means (53b) is decreased by a predetermined second set value or more with respect to the detection value of the other magnetic field detection means (54b). The fuel cell diagnostic apparatus according to claim 1, wherein the fuel cell diagnostic device is diagnosed as being deficient in oxidant gas. Comprising resistance measuring means (50 to 52) for measuring an internal resistance inside the fuel cell (1),
When the measured value measured by the resistance measuring means (50 to 52) is larger than a preset resistance value, the diagnostic means (50) is dry inside the fuel cell (1). 6. The fuel cell diagnosis apparatus according to claim 1, wherein the diagnosis is a state. The pair of magnetic field detecting means (53, 54) is disposed at a position shifted by a half circumference in the circumferential direction around the outer periphery of the power generation cell (10), and the fuel flows by the current flowing in the fuel cell (1). The strength of the magnetic field that is in the same direction as the direction of the magnetic flux generated in the outer periphery of the battery (1) is detected as positive,
The diagnostic means (50) is detected by the detected value detected by one magnetic field detecting means (53) and the other magnetic field detecting means (54) of the pair of magnetic field detecting means (53, 54). When the sum of the detected values is smaller than a preset first reference value, the fuel cell (1) generates power based on the detected values detected by the pair of magnetic field detecting means (53, 54). 7. The fuel cell diagnostic apparatus according to claim 1, wherein the condition is diagnosed. The pair of magnetic field detecting means (53, 54) is disposed at a position shifted by a half circumference in the circumferential direction around the outer periphery of the power generation cell (10), and the fuel flows by the current flowing in the fuel cell (1). Detecting the strength of the magnetic field in the same direction as the direction of the magnetic flux generated in the outer periphery of the battery (1) as negative,
The diagnostic means (50) is detected by the detected value detected by one magnetic field detecting means (53) and the other magnetic field detecting means (54) of the pair of magnetic field detecting means (53, 54). When the sum of the detected values is larger than a preset second reference value, the fuel cell (1) generates power based on the detected values detected by the pair of magnetic field detecting means (53, 54). 7. The fuel cell diagnostic apparatus according to claim 1, wherein the condition is diagnosed. The pair of magnetic field detection means (53, 54) is disposed at a position shifted by a half turn in the circumferential direction around the outer periphery of the power generation cell (10), and of the pair of magnetic field detection means (53, 54), One magnetic field detection means (53) detects the strength of the magnetic field in the same direction as the direction of the magnetic flux generated in the outer periphery of the fuel cell (1) by the current flowing in the fuel cell (1) as positive, The other magnetic field detection means (54) detects the strength of the magnetic field in the same direction as the direction of the magnetic flux as negative,
The diagnosis means (50) sets in advance a subtraction value obtained by subtracting the detection value detected by the other magnetic field detection means (54) from the detection value detected by the one magnetic field detection means (53). The power generation state of the fuel cell (1) is diagnosed based on the detection values detected by the pair of magnetic field detection means (53, 54) when it is smaller than the third reference value. Item 7. The fuel cell diagnostic device according to any one of Items 1 to 6.

Images