JP5655707B2 - Impedance measuring device - Google Patents

Description

  The present invention relates to an impedance measuring device that measures the impedance of a fuel cell using an alternating current impedance method.

  Conventionally, in order to grasp the internal state (internal moisture content, etc.) of a polymer electrolyte fuel cell, the current flowing through the local part of the cell of the fuel cell is measured, and the impedance of the fuel cell is measured using the AC impedance method. A configuration for measuring (impedance measuring device) has been proposed (see, for example, Patent Document 1).

  In Patent Document 1, when a high-frequency AC signal is superimposed on the output signals of the current detection unit and the voltage detection unit, the membrane resistance of the electrolyte membrane is estimated from the impedance of the fuel cell measured by the impedance measurement device. The amount of water inside the fuel cell is grasped.

  More specifically, the impedance measuring device includes a pair of electrodes and a current measuring unit having a resistor connecting each of the pair of electrodes and a pair of electrodes in order to detect a current flowing through a local portion of the fuel cell. A voltage detection unit that detects a potential difference between the electrodes, and a signal processing circuit that measures a current flowing through the current measurement unit using a detection value of the voltage detection unit and a resistance value of the resistor. Note that the current measuring unit is disposed adjacent to a local site of the cell.

JP 2009-252706 A

  However, the present inventors measured the impedance of the fuel cell when a high-frequency (for example, 400 Hz or more) AC signal was superimposed on the fuel cell as in the impedance measuring device described in Patent Document 1, and the membrane resistance of the electrolyte membrane As a result, it was found that the estimated value of the membrane resistance deviated from the actual membrane resistance value of the electrolyte membrane.

  Therefore, the present inventors investigated the cause, and the induced electromotive voltage generated by the current flowing through the resistor of the current measuring unit when a high-frequency AC signal was superimposed on the fuel cell detected the potential difference between the pair of electrodes. It has been found that it has an adverse effect on the signal lines of the voltage detection section. That is, when a high-frequency AC signal is superimposed on the fuel cell, the current flowing through the local portion of the fuel cell cannot be accurately measured due to the induced electromotive voltage generated by the current flowing through the resistor of the current measuring unit. I understood that.

  The present invention has been made in view of the above points, and an object thereof is to suppress a decrease in measurement accuracy of a current flowing through a local portion of a cell of a fuel cell due to the influence of an induced electromotive voltage when a high-frequency AC signal is superimposed on the fuel cell. .

In order to achieve the above object, according to the first aspect of the present invention, a fuel cell constructed by stacking and arranging a plurality of cells (10a) that output an electric energy by electrochemical reaction of an oxidant gas and a fuel gas. An impedance measuring device for measuring impedance in a cell (10a) of (10), which is disposed on both sides of a plate member (100a) disposed adjacent to the cell (10a) and the plate member (100a). The pair of electrodes (111, 121) having a predetermined electric resistance value are electrically connected to each other, and a current flows in a direction orthogonal to the stacking direction of the cells (10a). Current measuring unit (101) having a resistive element (131, 141) and a first connecting part for connecting the first electrode (111) and the resistive element (131, 141) in the pair of electrodes (111, 121) 101b), a potential difference detecting means (103) for detecting a potential difference between the second connection part (101c) connecting the resistor (131, 141) and the second electrode (121), and a sine wave of a predetermined frequency are superimposed. Current value detection means (51) for detecting a current value flowing through the current measurement unit (101) using the output signal of the potential difference detection means (103) and the electrical resistance value of the resistors (131, 141); The potential difference detection means (103) is electrically connected to the first connection portion (101b) via the first potential difference detection wiring (104), and via the second potential difference detection wiring (105). Each of the first potential difference detection wiring (104) and the second potential difference detection wiring (105) is electrically connected to the second connection portion (101c), and each plate member is at least from the stacking direction of the cells (10a). Site of polymerizing with the resistor (131, 141) when viewed 100a), characterized in that it is perpendicular to the shape to the flow direction of the current flowing through resistor body (131, 141).

  According to this, at least a portion overlapping with the resistor (131, 141) in the first potential difference detection wiring (104) and the second potential difference detection wiring (105), the current flowing through the resistor (131, 141) Since the shape is orthogonal to the flow direction, the induced electromotive voltage caused by the current flowing through the resistor (131, 141) has an adverse effect on the first potential difference detection wiring (104) and the second potential difference detection wiring (105). Can be suppressed. As a result, it is possible to suppress a decrease in measurement accuracy of the current flowing through the local portion of the cell (10a) of the fuel cell (10) due to the influence of the induced electromotive voltage when a high-frequency AC signal is superimposed on the fuel cell (10). it can.

  Further, in the invention according to claim 2, in the impedance measuring device according to claim 1, the resistors (131, 141) are electrically connected to the first electrode (111) via the first connection portion (101b). A first resistor part (131) connected to the second electrode (121) via a second connection part (101c) and a second resistor part (141) electrically connected to the first resistor The portion (131) and the second resistance portion (141) are arranged so as to overlap each other when the plate member (100a) is viewed from the stacking direction of the cells (10a), and the first resistance portion (131). The flow direction of the current flowing through the second resistor portion (141) is opposite to the flow direction of the current flowing through the second resistance portion (141).

  According to this, since the flow direction of the current flowing through the first resistance portion (131) and the flow direction of the current flowing through the second resistance portion (141) are opposite to each other, the first resistance portion It is possible to cancel the magnetic field generated by the current flowing through (131) and the magnetic field generated by the current flowing through the second resistance portion (141). Thereby, since generation | occurrence | production of the induced electromotive voltage at the time of superimposing a high frequency alternating current signal on a fuel cell (10) can be suppressed, the measurement precision of the electric current which flows through the local site | part of the cell (10a) of a fuel cell (10) Can be effectively suppressed.

  Moreover, in invention of Claim 3, in the impedance measuring apparatus of Claim 1 or 2, a plate-shaped member (100a) is comprised with the laminated substrate on which the several board | substrate (110-160) was laminated | stacked, The first potential difference detection wiring (104) and the second potential difference detection wiring (105) are at least partially formed on the same substrate.

  As described above, at least a part of each potential difference detection wiring (104, 105) may be integrated on the same substrate.

  Moreover, in invention of Claim 4, in the impedance measuring apparatus of Claim 1 or 2, a plate-shaped member (100a) is comprised with the laminated substrate on which the several board | substrate (110-160) was laminated | stacked, The first potential difference detection wiring (104) and the second potential difference detection wiring (105) are formed on different substrates among the plurality of substrates (110 to 160).

  According to this, since each potential difference detection wiring (104, 105) does not interfere on the substrate, the degree of freedom in designing the wiring on the substrate can be improved.

  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 schematic configuration diagram of a fuel cell system according to a first embodiment. 1 is a perspective view of a fuel cell according to a first embodiment. It is an exploded view of the current measurement part assembly board which concerns on 1st Embodiment. It is a schematic diagram which shows schematic structure of the electric current measurement part which concerns on 1st Embodiment. It is a schematic diagram which shows schematic structure of the electric current measurement part which concerns on 2nd Embodiment. It is a schematic diagram which shows schematic structure of the electric current measurement part which concerns on 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram showing a fuel cell system according to this embodiment. This fuel cell system is applied to a so-called fuel cell vehicle, which is a kind of electric vehicle, and includes an electric load, a secondary battery, etc. (not shown). It supplies power to the electrical equipment.

  As shown in FIG. 1, the fuel cell system of this embodiment includes a fuel cell 10 that generates electric power by utilizing an electrochemical reaction between hydrogen and oxygen. The fuel cell 10 supplies electric power to an electric load (not shown) or an electric device such as a secondary battery. Incidentally, in the case of an electric vehicle, an electric motor as a vehicle driving source corresponds to an electric load.

  In this embodiment, a solid polymer electrolyte fuel cell is used as the fuel cell 10, and a plurality of fuel cell cells 10a (hereinafter simply referred to as cells 10a) serving as a basic unit are arranged in a stacked manner and electrically. They are connected in series. In each cell 10a, as shown below, hydrogen and oxygen are electrochemically reacted to output electric energy.

(Negative electrode side) H ₂ → 2H ⁺ + 2e ⁻
(Positive electrode side) 2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O
The electric energy output from the fuel cell 10 is measured by a voltage sensor 11 that detects an output voltage that is output as the entire fuel cell 10 and a current sensor 12 that detects an output current output as the entire fuel cell 10. Detection signals of the voltage sensor 11 and the current sensor 12 are input to the control unit 50 described later.

  Further, between the stacked cells 10a, an impedance measuring device 100 that measures the current distribution in the cell surface of the fuel cell 10 and measures the impedance of each cell 10a is provided. The impedance measuring apparatus 100 is configured to include a measuring unit assembly plate 100a that is a plate-like member. The measurement unit assembly plate 100a of the impedance measurement apparatus 100 of the present embodiment is disposed between adjacent cells 10a and is electrically connected in series with the adjacent cells 10a. A detection signal of the impedance measuring apparatus 100 is input to the control unit 50 via a signal processing circuit 51 described later. Details of the impedance measuring apparatus 100 will be described later.

  Although not shown, the fuel cell 10 is provided with a sine wave oscillator as sine wave superimposing means for superimposing a sine wave of a predetermined frequency on the output current of the fuel cell 10. Thereby, a sine wave can be superimposed on output signals of the voltage sensor 11, the impedance measuring apparatus 100, and the like.

  The fuel cell system includes an air flow path 20 for supplying an oxidant gas (air) containing oxygen as a main component to the air electrode side (positive electrode side) of the fuel cell 10, and the hydrogen electrode side (negative electrode) of the fuel cell 10. A hydrogen channel 30 for supplying a fuel gas (hydrogen) containing hydrogen as a main component is provided on the side). Here, the upstream side of the fuel cell 10 in the air channel 20 is referred to as an air supply channel 20a, and the downstream side is referred to as an air discharge channel 20b. Further, the upstream side of the fuel cell 10 in the hydrogen channel 30 is referred to as a hydrogen supply channel 30a, and the downstream side is referred to as a hydrogen discharge channel 30b.

  An air pump 21 for pressure-feeding air sucked from the atmosphere to the fuel cell 10 is provided at the most upstream portion of the air supply channel 20a, and between the air pump 21 and the fuel cell 10 in the air supply channel 20a. Is provided with a humidifier 22 for humidifying the air. The air discharge passage 20b is provided with an air pressure regulating valve 23 for adjusting the pressure of air in the fuel cell 10.

  A high-pressure hydrogen tank 31 filled with hydrogen is provided at the most upstream portion of the hydrogen supply flow path 30a, and the fuel cell 10 is supplied between the high-pressure hydrogen tank 31 and the fuel cell 10 in the hydrogen supply flow path 30a. A hydrogen pressure regulating valve 32 for adjusting the pressure of the generated hydrogen is provided.

  The hydrogen discharge passage 30b is provided with a branching hydrogen circulation passage 30c that is connected to the downstream side of the hydrogen pressure regulating valve 32 in the hydrogen supply passage 30a and forms a closed loop. Then, hydrogen is circulated so that unreacted hydrogen is supplied to the fuel cell 10 again. The hydrogen circulation channel 30 c is provided with a hydrogen pump 33 for circulating hydrogen in the hydrogen channel 30.

  The fuel cell 10 needs to be maintained at a constant temperature (for example, about 80 ° C.) during operation to ensure power generation efficiency. For this reason, a cooling system for cooling the fuel cell 10 is provided. The cooling system is provided with a cooling water path 40 that circulates the cooling water (heat medium) in the fuel cell 10, a water pump 41 that circulates the cooling water, and a radiator (radiator) 43 that includes a fan 42.

  The cooling water path 40 is provided with a bypass path 44 for bypassing the radiator 43 and flowing the cooling water. A flow path switching valve 45 for adjusting the flow rate of the cooling water flowing through the bypass path 44 is provided at the junction of the cooling water path 40 and the bypass path 44. Further, a temperature sensor 46 is provided as a temperature detecting means for detecting the temperature of the cooling water flowing out from the fuel cell 10 near the outlet side of the fuel cell 10 in the cooling water path 40. By detecting the cooling water temperature by the temperature sensor 46, the temperature of the fuel cell 10 can be indirectly detected.

  The fuel cell system is provided with a control unit (ECU) 50 that performs various controls. The control unit 50 is composed of a well-known microcomputer comprising a CPU, ROM, RAM, etc. and its peripheral circuits. In addition to the detection signals from the voltage sensor 11, the current sensor 12, and the temperature sensor 46, a detection signal output from a signal processing circuit 51 of the impedance measuring apparatus 100 described later is input to the control unit 50.

  In the control unit 50 of the present embodiment, the distribution of impedance in the plane of the cell 10a is measured using the detection signal (current value) from the signal processing circuit 51 of the impedance measuring apparatus 100 and the detection signal from the voltage sensor 11. . Note that the configuration (software and hardware) for calculating the impedance of the cell 10 a in the control unit 50 constitutes an impedance calculation means, and functions as a part of the impedance measuring apparatus 100.

  Further, the control unit 50 outputs a control signal to the air pump 21, the humidifier 22, the air pressure regulating valve 23, the hydrogen pressure regulating valve 32, the hydrogen pump 33, the water pump 41, the flow path switching valve 45, etc. based on the calculation result. To do.

  Next, details of the impedance measuring apparatus 100 of the present embodiment will be described. The impedance measuring apparatus 100 includes a measurement unit aggregate plate 100a formed of a plate-shaped member, a plurality of current measurement units 101 provided on the measurement unit aggregate plate 100a, and a potential difference detection that detects a potential difference between predetermined portions of the current measurement unit 101. The signal processing circuit 51 for detecting the current of the local part corresponding to the arrangement position of the current measurement part 101 in the plane of the voltage detection part 103 and the cell 10a is provided.

  First, the measurement part assembly board 100a is demonstrated based on FIG. 2, FIG. FIG. 2 is an external perspective view of the fuel cell 10, and FIG. 3 is a perspective view of the measurement unit assembly plate 100a. As shown in FIG. 2, a plurality of measurement unit assembly plates 100a of the present embodiment are provided, and are arranged between adjacent cells 10a.

  Further, as shown in FIG. 3, the measurement unit assembly board 100 a is configured as a laminated board in which a plurality of printed boards 110 to 140 on which wiring patterns are formed (printed) are laminated. The impedance measuring apparatus 100 according to the present embodiment is configured by stacking four printed circuit boards, first to fourth printed circuit boards 110 to 140. These printed circuit boards 110 to 140 are integrated by hot pressing with an insulating adhesive (not shown) interposed therebetween.

  As each printed board 110-140, a general glass epoxy board can be used. Each of the printed boards 110 to 140 is formed with three through holes that penetrate the front and back of the multilayer board in the vicinity of two opposing sides (left and right sides in FIG. 3) at the periphery. These through holes function as manifolds through which air, hydrogen, and cooling water pass when the cells 10a are stacked.

  Further, between the manifolds on both sides, a plurality of current measuring units 101 are arranged in a matrix (lattice) in two orthogonal directions. More specifically, as shown in FIG. 3, the current measuring unit 101 is arranged in a matrix of 6 in the vertical direction on the paper surface and 7 in the horizontal direction on the paper surface. Yes.

  That is, in the present embodiment, a plurality of current measuring units 101 are arranged in the same adjacent cell 10a. As a result, the plurality of current measurement units 101 are arranged over the entire plate surface of the measurement unit assembly plate 100a. Therefore, in the impedance measurement device 100 of the present embodiment, the impedance distribution in the plane of the cell 10a. Can be measured.

  Next, details of the current measuring unit 101 will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating a schematic configuration of the current measurement unit 101 according to the present embodiment. In FIG. 4, one current measuring unit 101 in the measuring unit assembly plate 100a is partially extracted.

  As shown in FIG. 4, the current measurement unit 101 of the present embodiment includes a first electrode 111 that is in electrical contact with one cell 10a among the adjacent cells 10a, and an electrical connection with the other cell 10a among the adjacent cells 10a. The first electrode 111 and the second electrode 121 are electrically connected to each other, and the resistors 131 and 141 having a predetermined electric resistance value are electrically connected. In addition, the 1st electrode 111 and the 2nd electrode 121 are comprised as a pair of electrode, and are arrange | positioned at both surfaces of the measurement part assembly board 100a.

  Specifically, the first electrode 111 is disposed on the surface (front side in FIG. 4) facing the one cell 10 a of the first printed circuit board 110, and the second electrode 121 is disposed on the other side of the second printed circuit board 120. It is arrange | positioned in the surface (paper surface back | inner side of FIG. 4) which opposes the cell 10a.

  The resistors 131 and 141 include a plate-like first resistor 131 that is electrically connected to the first electrode 111 via a first via hole (first connecting portion) 101b described later, and a second via hole (first described later). 2 connection part) 101c, it has the plate-shaped 2nd resistance part 141 electrically connected to the 2nd electrode 121 via 101c.

  Specifically, the first resistance part 131 is disposed on the surface of the third printed circuit board 130 that faces the first printed circuit board 110 (the front side in FIG. 4), and the second resistance part 141 is the fourth printed circuit board. 140 is disposed on the surface facing the third printed circuit board 130 (the front side in FIG. 4).

  Each of the pair of electrodes 111 and 121 and each of the resistance parts 131 and 141 is made of a metal foil, and each of the resistance parts 131 and 141 is made of a material having a higher resistance value than the pair of electrodes 111 and 121. Yes. For example, the pair of electrodes 111 and 121 can be made of copper foil, and the resistance portions 131 and 141 can be made of nickel foil.

  Here, each printed circuit board 110-140 is provided with a plurality of round hole-shaped first through holes 101a penetrating each printed circuit board 110-140. The first printed circuit board 110 is provided with a plurality of round hole-shaped first via holes 101b penetrating the first printed circuit board 110, and the second and fourth printed circuit boards 120 and 140 have second and fourth holes. A plurality of round hole-shaped second via holes 101c penetrating the printed circuit boards 120 and 140 are provided.

  Inside these first through holes 101a and first and second via holes 101b and 101c, a conductor such as copper is provided. And the 1st resistance part 131 and the 2nd resistance part 141 are connected via the 1st through-hole 101a. As shown in FIG. 4, the first through hole 101 a has relief portions 106 formed on both end surfaces in the longitudinal direction. The relief portion 106 allows the first through hole 101 a to be connected to the first electrode 111 and the first through hole 101 a. It is insulated from the second electrode 151.

  In addition, the first electrode 111 and the first resistance part 131 are connected via the first via hole 101b, and the second electrode 121 and the second resistance part 141 are connected via the second via hole 101c. . Accordingly, the first and second via holes 101b and 101c constitute the first and second connection portions of the present embodiment, respectively. The first and second via holes 101b and 101c are provided so as to overlap when viewed from the stacking direction of the measurement unit assembly plate 100a. The first and second via holes 101b and 101c are configured not to be electrically connected to each other by the third printed circuit board 130.

  The first electrode 111 is connected to one end side of the first resistance part 131 via the first via hole 101b, and the second electrode 121 is connected to one end side of the second resistance part 141 via the second via hole 101c. Has been. Further, the other end side of the first resistance portion 131 is connected to the other end side of the second resistance portion 141 through the first through hole 101a.

  Therefore, in the resistors 131 and 141, as indicated by the white arrows in FIG. 4, a current flows from one end side to the other end side (from the bottom to the top) of the first resistor portion 131, and conversely the second resistor portion 141. Current flows from the other end side to the one end side (from the upper side to the lower side). That is, the first resistance part 131 and the second resistance part 141 include the direction of current flowing through the first resistance part 131 disposed on the first electrode 111 side and the second resistance part disposed on the second electrode 121 side. The flow direction of the current flowing through 141 is opposite to each other. In other words, a current flows through the first and second resistance portions 131 and 141 and the first through hole 101a by bending in a U-shape when viewed from the cross-section in the stacking direction of the measurement unit assembly plate 100a. As a result, the magnetic field due to the current flowing through the first resistance portion 131 and the magnetic field due to the current flowing through the second resistance portion 141 are canceled out.

  In addition, the first via hole (first connection portion) 101b and the second via hole (second connection portion) 101c are respectively connected to the potential difference detection voltage detection section via the first and second potential difference detection wirings 104 and 105, etc. 103 is connected.

  The potential difference detection voltage detector 103 constitutes a potential difference detector that detects a potential difference (between the first connection portion and the second connection portion) between two points of the first via hole 101b and the second via hole 101c. Then, the detection signal of the potential difference detection voltage detection unit 103 is output to the signal processing circuit 51.

  Here, the first potential difference detection wiring 104 constitutes a signal line connecting the first via hole 101b and the potential difference detection voltage detection unit 103, and the second potential difference detection wiring 105 is connected to the second via hole 101c and the potential difference detection. This constitutes a signal line for connecting the voltage detector 103 for use.

  As shown in FIG. 4, each potential difference detection wiring 104, 105 has a portion where it overlaps with each of the resistance parts 131, 141 when viewed from the stacking direction of the measurement unit assembly plate 100a (the stacking direction of the cells 10a). It has a shape extending in a direction (left and right direction on the paper) perpendicular to the flow direction (up and down direction on the paper) of the current flowing through the resistance portions 131 and 141. In particular, each of the potential difference detection wirings 104 and 105 is orthogonal to the flow direction of the current flowing through each of the resistance units 131 and 141 (up and down direction on the paper) at a portion corresponding to the power generation unit of the cell 10a in the current measurement unit 101. It is preferable to have a shape extending in the direction (left and right direction on the paper). Each of the potential difference detection wirings 104 and 105 is made of a metal foil (for example, a copper foil), like the pair of electrodes 111 and 121.

  Specifically, the first potential difference detection wiring 104 of the present embodiment is formed on the surface of the first printed circuit board 110 opposite to the surface on which the first electrode 111 is disposed so as to straddle each first via hole 101b. Yes.

  In addition, the second potential difference detection wiring 105 of the present embodiment is formed on the surface of the second printed circuit board 120 opposite to the arrangement surface of the second electrode 121 so as to straddle each second via hole 101c. A part of the printed circuit board 110 is formed on the surface opposite to the surface on which the first electrode 111 is disposed. The wiring provided on the second printed circuit board 120 in the second potential difference detecting wiring 105 is connected to the first printed circuit board 110 in the second potential difference detecting wiring 105 through the second through hole 101d penetrating each printed circuit board 110-140. It is connected to the wiring provided in

  Therefore, a part of the second potential difference detection wiring 105 of the present embodiment is formed on the first printed circuit board 110 on which the first potential difference detection wiring 104 is formed. In other words, at least a part of each of the potential difference detection wirings 104 and 105 is formed on the same substrate. In addition, a conductor such as copper is provided in the second through hole 101d in the same manner as the first through hole 101a and the first and second via holes 101b and 101c.

  As shown in FIG. 3, a connector 113 for connecting the first and second potential difference detection wirings 104 and 105 and the potential difference detection voltage detection unit 103 is provided on one side of the first printed circuit board 110. ing.

  The signal processing circuit 51 of the impedance measuring apparatus 100 performs an arithmetic process using the detection signal (detected potential difference) of the voltage detection unit 103 for detecting the potential difference and the electric resistance values of the resistors 131 and 141, so that the in-plane of the cell 10a. The value of the current flowing through the part corresponding to each current measuring unit 101 is detected. Specifically, the signal processing circuit 51 divides the detection signal (detection potential difference) of the potential difference detection voltage detection unit 103 by the electric resistance values of the resistors 131 and 141, so that a portion corresponding to the current measurement unit 101 is obtained. The flowing current value is detected. Therefore, the signal processing circuit 51 constitutes a current value detecting means for detecting a current value flowing through a local part in the cell 10a. The current value detected by the signal processing circuit 51 is output to the control unit 50.

  Next, a current measuring method and an impedance measuring method by the impedance measuring apparatus 100 and the control unit 50 of the present embodiment will be described. It is assumed that at the time of current measurement and impedance measurement, a sine wave having a predetermined frequency is superimposed on the output current of the fuel cell 10 by a sine wave oscillator.

  When the supply of hydrogen and air to the fuel cell 10 is started, power generation in the fuel cell 10 is started. In each current measuring unit 101 of the impedance measuring apparatus 100, a current flows from the cell 10a on the upstream side in the current flow direction to the plate surface of the first electrode 111, as shown in FIG. Then, current flows in the order of the first electrode 111 → the first via hole 101b → the first resistance portion 131 → the first through hole 101a → the second resistance portion 141 → the second via hole 101c → the second electrode 121, and the second electrode 121 Current flows from the plate surface to the cell 10a downstream in the current flow direction.

  At this time, the potential difference detection voltage detection unit 103 measures the potential difference between one end side of the first resistance unit 131 (first via hole 101b) and one end side of the second resistance unit 141 (second via hole 101c).

  Then, the signal processing circuit 51 calculates the magnitude of the current flowing through the resistors 131 and 141 using the detected potential difference by the potential difference detection voltage detector 103 and the electric resistance values of the resistors 131 and 141. Thereby, the signal processing circuit 51 can measure the current value of the part corresponding to each current measuring unit 101 of the impedance measuring apparatus 100 in the plane of the cell 10a, that is, the distribution of impedance in the plane of the cell 10a.

  Next, the control unit 50 measures the local impedance of the cell 10a by a known AC impedance method using each current value measured by the signal processing circuit 51 and the detection signal of the voltage sensor 11. Specifically, the AC component of the sine wave superimposed by the sine wave oscillator (frequency analysis processing such as fast Fourier transform processing) from each current value measured by the signal processing circuit 51 and the detection signal of the voltage sensor 11 ( Current component and voltage component) are extracted, and the local impedance of the cell 10a is calculated using the extracted AC component.

  According to the impedance measuring apparatus 100 of the present embodiment described above, at least the resistors 131 and 141 in the first potential difference detection wiring 104 and the second potential difference detection wiring 105 connected to the potential difference detection voltage detection unit 103 are overlapped with each other. The portion to be operated is shaped to be orthogonal to the flow direction of the current flowing through the resistors 131 and 141. Therefore, the induced electromotive voltage due to the current flowing through the resistors 131 and 141 is the first potential difference detection wiring 104 and the second potential difference detection. The adverse effect on the wiring 105 can be suppressed. As a result, it is possible to suppress a decrease in measurement accuracy of the current flowing through the local portion of the cell 10a of the fuel cell 10 due to the influence of the induced electromotive voltage when a high-frequency AC signal is superimposed on the fuel cell 10. Further, when the local impedance of the cell 10a of the fuel cell 10 is measured using the current value measured by the impedance measuring device 100, the local impedance can be detected with high accuracy, so that the internal moisture content of the fuel cell Etc. can be properly grasped.

  Moreover, in the impedance measuring apparatus 100 of this embodiment, since the flow direction of the electric current which flows through the 1st resistance part 131 which is the resistors 131 and 141 and the 2nd resistance part 141 becomes a reverse direction, it is comprised. The magnetic field generated by the current flowing through the first resistance portion 131 and the magnetic field generated by the current flowing through the second resistance portion 141 can be canceled out. As a result, it is possible to suppress the generation of the induced electromotive voltage itself when a high-frequency AC signal is superimposed on the fuel cell 10, thereby effectively reducing the measurement accuracy of the current flowing through the local portion of the cell 10 a of the fuel cell 10. Can be suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic diagram illustrating a schematic configuration of the current measurement unit 101 according to the present embodiment. In the present embodiment, description of the same or equivalent parts as in the first embodiment will be omitted or simplified.

  In the impedance measuring apparatus 100 of the present embodiment, the first potential difference detection wiring 104 is formed on a different substrate from the first electrode 111, and the second potential difference detection wiring 105 is formed on a different substrate from the second electrode 121. This is different from the first embodiment.

  In the impedance measuring apparatus 100 of the present embodiment, the measurement unit assembly plate 100a is configured by a laminated substrate in which six printed substrates 110 to 160 are laminated. Specifically, in the measurement unit assembly board 100a of this embodiment, a fifth printed board 150 is added between the first printed board 110 and the third printed board 130, and the second printed board 120 and the fourth printed board are added. A sixth printed circuit board 160 is added between the second printed circuit board 140 and the second printed circuit board 140. The basic configuration of the added fifth and sixth printed circuit boards 150 and 160 is the same as that of the first to fourth printed circuit boards 110 to 140.

  Then, the first potential difference detection wiring 104 is formed on the surface (front side of the sheet) of the fifth printed circuit board 150 that faces the first printed circuit board 110, and the surface of the sixth printed circuit board 160 that faces the fourth printed circuit board 140 ( A second potential difference detection wiring 105 is formed on the front side of the drawing.

  As described above, in the impedance measuring apparatus 100 according to the present embodiment, although the laminated structure of the measurement unit assembly plate 100a is changed, at least the resistors 131 and 141 in the first and second potential difference detection wirings 104 and 105 are overlapped. Since the portion to be made is in a shape orthogonal to the flow direction of the current flowing through the resistors 131 and 141, the current flowing through the local portion of the cell 10a of the fuel cell 10 is the same as the impedance measuring device 100 described in the first embodiment. It is possible to suppress a decrease in measurement accuracy.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic diagram illustrating a schematic configuration of the current measurement unit 101 according to the present embodiment. In the present embodiment, description of the same or equivalent parts as in the first and second embodiments will be omitted or simplified.

  This embodiment is different from the second embodiment in that the first potential difference detection wiring 104 and the second potential difference detection wiring 105 are formed on different printed boards among the plurality of printed boards 110 to 160. Yes.

  Specifically, the first potential difference detection wiring 104 is formed on the surface (front side of the paper) of the fifth printed circuit board 150 facing the first printed circuit board 110, and the second potential difference detection wiring 105 is connected to the sixth printed circuit board. The substrate 160 is formed on the surface (front side of the paper) facing the fourth printed circuit board 140. The first potential difference detection wiring 104 and the second potential difference detection wiring 105 are formed on the fifth and sixth printed circuit boards 150 and 160 so as to have the same shape when viewed from the stacking direction of the measurement unit assembly plate 100a. Is formed.

  Although not shown, a connector for connecting the first potential difference detection wiring 104 and the potential difference detection voltage detection unit 103 is provided on one side of the fifth printed circuit board 150 of the present embodiment. A connector for connecting the second potential difference detection wiring 105 and the potential difference detection voltage detection unit 103 is provided on one side of 160.

  As described above, in the impedance measuring apparatus 100 according to the present embodiment, the arrangement structure of the potential difference detection wires 104 and 105 in the measurement unit assembly plate 100a is changed, but the first and second potential difference detection wires 104 and 105 are changed. Since at least the portion that overlaps with the resistors 131 and 141 has a shape orthogonal to the flow direction of the current flowing through the resistors 131 and 141, similarly to the impedance measuring apparatus 100 described in the first and second embodiments, A decrease in measurement accuracy of the current flowing through the local portion of the cell 10a of the fuel cell 10 can be suppressed.

  Further, when the potential difference detection wirings 104 and 105 are provided on different printed circuit boards as in the present embodiment, the degree of freedom in designing the wirings on the printed circuit board can be improved.

(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 each of the above-described embodiments, the example in which the flow direction of the current flowing through each of the resistance units 131 and 141 is set to the vertical direction has been described. However, the present invention is not limited to this example. The flow direction may be the left-right direction. In this case, each of the potential difference detection wirings 104 and 105 may have a shape extending in the vertical direction so as to be orthogonal to the flow direction of the current flowing through each of the resistance portions 131 and 141.

  (2) As in each of the above-described embodiments, the resistor is preferably configured by a pair of resistor units 131 and 141. However, the present invention is not limited to this, and the resistor may be configured by one resistor unit.

  (3) In each of the above-described embodiments, an example in which the measurement unit assembly plate 100a is configured by a laminated substrate in which a plurality of printed boards are stacked has been described. Can do.

  (4) In the second and third embodiments described above, the example in which the first potential difference detection wiring 104 is formed on the surface of the fifth printed circuit board 150 facing the first printed circuit board 110 has been described. However, the present invention is not limited thereto. For example, the first potential difference detection wiring 104 may be formed on the surface of the fifth printed circuit board 150 that faces the third printed circuit board 130. Similarly, the second potential difference detection wiring 104 may be formed on the surface of the sixth printed board 160 facing the second printed board 120.

  (5) In each of the above-described embodiments, the example in which the first and second through holes 101a and 101d and the first and second via holes 101b and 101c are round holes has been described. However, the present invention is not limited to this. It is good also as a hole shape.

  (6) In each of the above-described embodiments, the impedance measuring apparatus 100 is provided with a plurality of current measuring units 101 corresponding to the entire surface of the cell 10a. However, if at least one current measuring unit 101 is provided. Good. Thereby, the local current of the site | part corresponding to the electric current measurement part 101 in the cell 10a can be measured.

  (7) In each of the above-described embodiments, the impedance measuring device 100 is arranged between the adjacent cells 10a. However, the present invention is not limited to this. For example, the impedance measuring device 100 is arranged at the stacking direction end of the cells 10a in the fuel cell 10. In this case, it may be arranged adjacent to the cell 10a at the end in the stacking direction. According to this, it is possible to measure the local current in the cell plane at the end of the fuel cell 10 in the stacking direction of the cells 10a.

10 Fuel cell 10a Fuel cell (cell)
100 Impedance measuring device 100a Measuring unit assembly plate (plate-like member)
101 Current measurement unit 101b First via hole (first connection unit)
101c Second via hole (second connection part)
103 Voltage detection unit for potential difference detection (potential difference detection means)
104 1st potential difference detection wiring 105 2nd potential difference detection wiring 111 1st electrode 121 2nd electrode 131 1st resistance part (resistor)
141 2nd resistance part (resistor)

Claims (4)

Impedance measurement for measuring the impedance of the cell (10a) of the fuel cell (10) configured by stacking and arranging a plurality of cells (10a) for outputting electric energy by electrochemical reaction of an oxidant gas and a fuel gas. A device,
A plate-like member (100a) disposed adjacent to the cell (10a);
A pair of electrodes (111, 121) disposed on both surfaces of the plate-like member (100a), a pair of electrodes (111, 121) having a predetermined electric resistance value, and electrically connected to the cell (10a) current measuring unit that direction current having a flow Ru resistor (131, 141) perpendicular to the stacking direction) and (101),
The first connection part (101b) for connecting the first electrode (111) and the resistor (131, 141) in the pair of electrodes (111, 121), and the resistor (131, 141) and the second electrode A potential difference detecting means (103) for detecting a potential difference between the second connecting portions (101c) connecting (121);
A current value flowing through the current measuring unit (101) is detected using an output signal of the potential difference detecting means (103) to which a sine wave having a predetermined frequency is applied and an electric resistance value of the resistor (131, 141). Current value detecting means (51) for providing,
The potential difference detection means (103) is electrically connected to the first connection portion (101b) via the first potential difference detection wiring (104) and also via the second potential difference detection wiring (105). Electrically connected to the second connection part (101c),
Each of the first potential difference detection wiring (104) and the second potential difference detection wiring (105) has the resistor (100a) when viewed from at least the plate member (100a) from the stacking direction of the cells (10a). 131, 141), and the position where it overlaps with the flow direction of the current flowing through the resistor (131, 141). The resistor (131, 141) includes a first resistor (131) electrically connected to the first electrode (111) via the first connection (101b), and the second connection ( 101c) having a second resistance part (141) electrically connected to the second electrode (121) through
The first resistance part (131) and the second resistance part (141) are arranged so as to overlap each other when the plate-like member (100a) is viewed from the stacking direction of the cells (10a), The structure according to claim 1, wherein the flow direction of the current flowing through the first resistance portion (131) and the flow direction of the current flowing through the second resistance portion (141) are opposite to each other. The impedance measuring apparatus described. The plate-like member (100a) is composed of a laminated substrate in which a plurality of substrates (110 to 160) are laminated,
The impedance according to claim 1 or 2, wherein at least a part of the first potential difference detection wiring (104) and the second potential difference detection wiring (105) are formed on the same substrate. measuring device. The plate-like member (100a) is composed of a laminated substrate in which a plurality of substrates (110 to 160) are laminated,
The first potential difference detection wiring (104) and the second potential difference detection wiring (105) are formed on different substrates among the plurality of substrates (110 to 160). The impedance measuring apparatus according to 1 or 2.

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