JP6421717B2 - Current measuring device - Google Patents

Description

  The present invention relates to a current measuring device for measuring a current flowing inside a fuel cell.

  As this current measuring device, Patent Document 1 discloses a shunt-type current measuring device. The current measurement device of Patent Document 1 includes a current measurement unit that is disposed between adjacent cells of a fuel cell. The current measuring unit is located between the first electrode in a flat plate shape that contacts one of the adjacent cells, the second electrode in a flat shape contacted with the other of the adjacent cells, and the first and second electrodes, The resistor is electrically connected to the second electrode. In this current measuring device, the current passing through the current measuring unit from one of the adjacent cells to the other is detected based on the potential difference between both ends of the resistor and the resistance value of the resistor.

JP2012-113848A

  By the way, the present inventors examined the thing of the structure shown to FIGS. 6-8 as a current measurement part used for a shunt-type current measuring apparatus. Hereinafter, this is referred to as a current measurement unit of the examination example. In addition, in FIGS. 6-8, the same code | symbol is attached | subjected to the same structure part as the electric current measurement part of embodiment mentioned later.

  As shown in FIGS. 6 and 7, the current measuring unit J2a of the examination example includes insulating layers 201, 202, and 203 disposed between the first electrode 211 and the second electrode 212. In this current measurement unit, the resistor J220 is configured by resistance members J221a, J222a, and J223a embedded in through holes J201a, J202a, and J203a formed through both surfaces of the insulating layers 201, 202, and 203. ing.

  As shown in FIG. 8, in the current measurement unit J2a of the examination example, a plurality (four in FIG. 8) of through holes J201a are formed in the insulating layer 201 as through holes for forming the resistor. And the opening shape of one through-hole J201a is a perfect circle shape with a diameter Ra, that is, the first opening width L1 in the first direction and the second opening width L2 in the second direction orthogonal to the first direction are the same shape. (L1 = L2 = Ra). For this reason, the resistance member J222a embedded in one through-hole J201a has a cylindrical shape. The same applies to the through holes J202a and J203a of the insulating layers 202 and 203 and the resistance members J222a and J223a.

  Here, unlike the current measurement unit J2a of the study example, when the resistor is formed on the surface of the insulating layer, the resistance value of the resistor is set to a size necessary for measuring the current flowing inside the fuel cell. Requires thicker resistors. For this reason, a current measurement part will become thick.

  On the other hand, according to the current measurement unit J2a of the examination example, the resistors (that is, the resistance members J221a to J223a) are formed inside the insulating layers 201 to 203, so that the number of insulating layers is the same. Compared with the case where a resistor is formed on the surface of the insulating layer, the current measuring portion J2a can be made thinner.

  However, when the current measurement part J2a of the examination example is used, it has been found that the accuracy of current measurement needs to be improved for the following reason.

  The first reason is that a manufacturing variation occurs in the resistance values of the resistance members J222a to J223a embedded in one through hole J201a to J203a, and a variation in the resistance value of the resistor J220 due to this manufacturing variation is large.

  The second reason is that the variation in the contact resistance between the current measuring unit J2a and the cell is large. This is because the current measuring unit J2a in the examination example has the resistance members J221a, J222a, and J223a of the insulating layers 201, 202, and 203, respectively, when viewed from the direction perpendicular to the surfaces of the first and second electrodes 211 and 212. Are placed at overlapping positions. That is, as shown in FIGS. 6 and 7, the resistance members J221a, J222a, and J223a are connected in a straight line in a direction perpendicular to the first and second electrodes 211 and 212. Since each resistance member J221a, J222a, J223a has higher rigidity than each insulating layer 201, 202, 203, when the measurement plate 2 is sandwiched between adjacent cells and pressed, each resistance member J221a, J222a, J223a protrudes, and unevenness is generated on the surfaces 211a and 212a of the first and second electrodes 211 and 212. For this reason, a gap is generated between each of the surfaces 211a and 212a of the first and second electrodes 211 and 212 and the surface of the facing cell. Thereby, the dispersion | variation in contact resistance will become large.

  In view of the above points, an object of the present invention is to provide a current measurement device capable of improving current measurement accuracy as compared with the case where the current measurement unit J2a of the study example is used.

In order to achieve the above object, in the invention described in claim 1,
A current measuring unit (2a) for measuring a current flowing inside a fuel cell (10) in which a plurality of cells (10a) are stacked, and facing a first electrode (211) having a flat plate shape and the first electrode A plate-shaped second electrode (212) arranged between the first and second electrodes, and a resistor (220, L220, M220) electrically connected to the first and second electrodes; A current measuring unit in which at least one of the first and second electrodes is in contact with the cell;
Current detection means (3) for detecting a current flowing between the first and second electrodes based on a potential difference between the first and second electrodes and a resistance value of a current path between the first and second electrodes. 4)
The current measuring unit includes an insulating layer (201, 202, 203) disposed between the first and second electrodes,
The resistor is composed of a resistance member (221a, 222a, 223a) embedded in a through hole (201a, 202a, 203a) formed through both surfaces of the insulating layer,
The opening shape of the through hole is such that the first opening width (L1) in the first direction is longer than the second opening width (L2) in the second direction orthogonal to the first direction. It is a feature.

  Here, when the dimensional error that occurs during processing of the through hole is the same, the ratio of the actual size error to the design size of the opening width is larger when the opening width of the through hole is longer than when the opening width is short Becomes smaller.

  Accordingly, in the present invention, the first opening width of the through hole is made larger than the opening width of one through hole in the current measurement unit of the study example, so that the first opening width is larger than that of the current measurement unit of the study example. The ratio of the actual size error to the design size can be reduced. For this reason, variation in resistance value of the resistor due to variation in manufacturing can be reduced.

  Therefore, according to the present invention, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit of the examination example.

Furthermore, in the invention according to claim 1 ,
The insulating layer includes a first electrode side insulating layer (201) having a first electrode formed on the surface, and a second electrode side insulating layer (202, 203) having a second electrode formed on the surface,
The resistance member is embedded in a through hole (201a) penetrating both surfaces of the first electrode-side insulating layer, and the first electrode-side resistance member (221a) connected to the first electrode and both surfaces of the second electrode-side insulating layer. A second electrode side resistance member (222a, 223a) embedded in the through hole (202a, 203a) penetrating the first electrode and connected to the second electrode,
The first and second electrode side resistance members are spaced apart from each other in a direction parallel to the surfaces of the first and second electrodes, and are formed between the first electrode side insulating layer and the second electrode side insulating layer. Connected to each other through the conductive layers (K233, M233),
The current measurement unit has at least one of a first recess (241) provided on the surface of the first electrode and a second recess (242) provided on the surface of the second electrode,
The first recess has a second electrode side resistance member projected onto the surface of the first electrode when the second electrode side resistance member is projected onto the surface of the first electrode in a direction perpendicular to the surface of the first electrode. Provided in a position overlapping with the region (R1),
The second recess has a first electrode side resistance member projected onto the surface of the second electrode when the first electrode side resistance member is projected onto the surface of the second electrode in a direction perpendicular to the surface of the second electrode. It is characterized by being provided at a position overlapping with the region (R2).

  According to this, in the case of having the first recess on the surface of the first electrode, the second electrode side resistance member is formed in the current measurement unit when the current measurement unit receives pressure from the second electrode side. The part can be bent toward the first electrode. Thereby, when the 2nd electrode and a cell are made to contact, the surface pressure which a 2nd electrode receives can be closely approached uniformly.

  Similarly, when the second electrode has a second recess on the surface, when the current measurement unit receives pressure from the first electrode side, the portion of the current measurement unit where the first electrode-side resistance member is formed is , Can be deflected to the second electrode side. Thereby, when the first electrode and the cell are brought into contact with each other, the surface pressure received by the first electrode can be made close to uniform.

  For this reason, variation in contact resistance that occurs when the first electrode and the second electrode are brought into contact with the cell can be reduced. Therefore, according to the present invention, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit of the examination example.

In the invention according to claim 2 , in the invention according to claim 1 ,
The conductor layer (M233) has a first connection region (M1) connected to the first electrode-side resistance member and a second connection region (M2) connected to the second electrode-side resistance member. At least a part of the region sandwiched between the first connection region and the second connection region is a conductor layer non-formation region (M3).

  According to this, by forming at least a part of the region sandwiched between the first connection region and the second connection region as a non-formation region of the conductor layer, the region sandwiched between the first connection region and the second connection region The resistance value of the conductor layer can be increased as compared with the case where the entire region is a conductor layer formation region. For this reason, the resistance value of the entire current path between the first electrode and the second electrode including the resistor and the conductor layer can be increased.

  Here, when the resistance value error of the resistor is compared under the same condition, the larger the resistance value of the entire current path, the smaller the ratio of the resistance value error of the resistor to the resistance value of the entire current path. .

  Therefore, according to the present invention, it is possible to reduce variations in the resistance value of the entire current path by increasing the resistance value of the entire current path without changing the resistance value of the resistor. Therefore, according to the present invention, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit of the examination example.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is an overall configuration diagram of a fuel cell system according to a first embodiment. It is a lineblock diagram of current measuring device 1 in a 1st embodiment. FIG. 5 is a cross-sectional view of one current measurement unit 2a in FIG. 2, and is a cross-sectional view taken along line AA in FIG. It is a disassembled perspective view of the electric current measurement part 2a shown in FIG. FIG. 4 is a top view of a first insulating layer 201 in FIG. 3. It is sectional drawing of the electric current measurement part J2a of an examination example, and is BB arrow sectional drawing in FIG. It is a disassembled perspective view of the electric current measurement part J2a shown in FIG. FIG. 7 is a top view of the first insulating layer 201 in FIG. 6. It is a figure which shows the ratio of resistance variation in each of the current measurement part of 1st-4th embodiment. It is sectional drawing of the electric current measurement part 2a of 2nd Embodiment, and is CC sectional view taken on the line in FIG. It is a disassembled perspective view of the electric current measurement part 2a shown in FIG. It is sectional drawing of the electric current measurement part 2a of 3rd Embodiment, and is DD sectional view taken on the line in FIG. It is a disassembled perspective view of the current measurement part 2a shown in FIG. It is sectional drawing of the electric current measurement part 2a of 4th Embodiment, and is EE arrow sectional drawing in FIG. It is a disassembled perspective view of the electric current measurement part 2a shown in FIG. It is a top view of the conductor pattern M233 in FIG. It is a top view of conductor pattern K233 in a 3rd embodiment. It is sectional drawing of the electric current measurement part 2a of 5th Embodiment, and is FF arrow sectional drawing in FIG. It is a disassembled perspective view of the electric current measurement part 2a shown in FIG. It is a top view of the conductor pattern in other embodiments.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
First, a fuel cell system to which the current measuring device of this embodiment shown in FIG. 1 is applied will be described. This fuel cell system is applied to a so-called fuel cell vehicle, which is a kind of electric vehicle, and supplies electric power to an electric load such as an electric motor for vehicle travel.

  As shown in FIG. 1, the fuel cell system includes a fuel cell 10 that generates electric power using an electrochemical reaction between hydrogen and oxygen. The fuel cell 10 outputs electric energy supplied to an electric load such as an electric motor for driving a vehicle (not shown), a secondary battery, and various auxiliary machines for vehicles. In this embodiment, a solid polymer electrolyte fuel The battery is adopted.

  More specifically, the fuel cell 10 is configured by electrically connecting a plurality of fuel cell cells 10a (hereinafter simply referred to as cells 10a) as basic units. 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 fuel cell 10 is electrically connected to a secondary battery via a DC-DC converter (not shown). The DC-DC converter controls the flow of power from the fuel cell 10 to the secondary battery or from the secondary battery to the fuel cell 10, and can exchange power bidirectionally regardless of the magnitude of the voltage. Yes.

  Furthermore, the electrical energy output from the fuel cell 10 is measured by a cell monitor 11 that detects a voltage output from each cell 10a of the fuel cell 10 and a current sensor 12 that detects a current output as the fuel cell 10 as a whole. Is done. Note that detection signals from the cell monitor 11 and the current sensor 12 are input to a control device 50 described later.

  Further, on the air electrode (positive electrode) side of the fuel cell 10, an air supply pipe 20 a for supplying air (oxygen) as an oxidant gas to the fuel cell 10, and the electrochemical reaction in the fuel cell 10 are finished. An air discharge pipe 20b for discharging the surplus air and generated water generated by the air electrode from the fuel cell 10 to the outside air is connected.

  An air pump 21 is provided at the most upstream portion of the air supply pipe 20a to pump air sucked from the atmosphere to the fuel cell 10, and an air discharge pipe 20b adjusts the pressure of the air in the fuel cell 10. An air pressure regulating valve 23 is provided.

  Further, the air supply pipe 20 a and the air discharge pipe 20 b are provided with a humidifier 22 for moving the humidity (water vapor) of the air flowing out from the air pressure regulating valve 23 to the air pumped from the air pump 21. . The humidifier 22 functions to humidify the air supplied to the fuel cell 10.

  On the hydrogen electrode (negative electrode) side of the fuel cell 10, a hydrogen supply pipe 30 a for supplying hydrogen, which is a fuel gas, to the fuel cell 10, and generated water accumulated on the hydrogen electrode side together with a small amount of hydrogen from the fuel cell 10 to the outside air A hydrogen discharge pipe 30b is connected to discharge. Furthermore, the hydrogen supply pipe 30a and the hydrogen discharge pipe 30b are connected via a hydrogen circulation pipe 30c.

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

  The hydrogen discharge pipe 30b is provided with an electromagnetic valve 34 that opens and closes at predetermined time intervals in order to discharge the produced water together with a small amount of hydrogen to the outside air. In the above-described electrochemical reaction, generated water is not generated on the hydrogen electrode side, but generated water that has permeated the electrolyte membrane of each cell 10a from the oxygen electrode side may accumulate on the hydrogen electrode side. Therefore, in this embodiment, the hydrogen discharge pipe 30b and the electromagnetic valve 34 are provided.

  The hydrogen circulation pipe 30c is provided to connect the downstream side of the hydrogen pressure regulating valve 32 of the hydrogen supply pipe 30a and the upstream side of the electromagnetic valve 34 of the hydrogen discharge pipe 30b. Thereby, the unreacted hydrogen flowing out from the fuel cell 10 is circulated to the fuel cell 10 and re-supplied. Further, a hydrogen pump 33 for circulating hydrogen in the hydrogen flow path 30 is disposed in the hydrogen circulation pipe 30c.

  By the way, the fuel cell 10 needs to be maintained at a constant temperature (for example, about 80 ° C.) during operation in order to ensure power generation efficiency. Therefore, a cooling water circuit 40 for cooling the fuel cell 10 is connected to the fuel cell 10. The coolant circuit 40 is provided with a water pump 41 that circulates coolant (heat medium) in the fuel cell 10 and a radiator 43 that includes an electric fan 42.

  Further, the cooling water circuit 40 is provided with a bypass flow path 44 through which the cooling water flows so as to bypass the radiator 43. A flow path switching valve 45 for adjusting the flow rate of the cooling water flowing through the bypass flow path 44 is provided at the junction of the cooling water circuit 40 and the bypass flow path 44. The cooling capacity of the cooling water circuit 40 is adjusted by adjusting the valve opening degree of the flow path switching valve 45.

  Further, a temperature sensor 46 as a temperature detecting means for detecting the temperature of the cooling water flowing out from the fuel cell 10 is provided in the vicinity of the outlet side of the fuel cell 10 in the cooling water circuit 40. By detecting the cooling water temperature by the temperature sensor 46, the temperature of the fuel cell 10 can be indirectly detected. The detection signal of the temperature sensor 46 is also input to the control device 50.

  The control device 50 controls the operation of various electric actuators constituting the fuel cell system on the basis of input signals, and is composed of a well-known microcomputer comprising a CPU, ROM, RAM, etc. and its peripheral circuits. Yes.

  Specifically, on the input side of the control device 50, in addition to the detection signals of the cell monitor 11, the current sensor 12 and the temperature sensor 46 described above, a current signal output from a current detection circuit 3 of a current measurement device to be described later. Is entered. On the other hand, on the output side, various electric actuators such as the air pump 21, the air pressure regulating valve 23, the hydrogen pressure regulating valve 32, the hydrogen pump 33, the electromagnetic valve 34, the water pump 41, and the flow path switching valve 45 are connected. Yes.

  Next, details of the current measuring apparatus of the present embodiment will be described.

  As shown in FIG. 2, the current measurement device 1 includes a measurement plate 2 for measuring a current flowing inside the fuel cell 10 and a current detection circuit 3. Furthermore, the current measuring device 1 includes a voltage sensor 4 shown in FIG.

  As shown in FIG. 2, the measurement plate 2 is disposed between adjacent cells 10 a of the fuel cell 10. The measurement plate 2 is a plate-like member in which a plurality of current measurement units 2a are integrally formed. The current measuring unit 2a measures a current in a region of the cell 10a facing the current measuring unit 2a, and measures a current flowing from one of the adjacent cells 10a to the other as described later. The plurality of current measurement units 2 a are arranged in a matrix in the surface direction of the measurement plate 2. Thereby, when the measuring plate 2 is arranged between the adjacent cells 10a, a plurality of current measuring units 2a are arranged in the surface direction of the cell 10a. Therefore, in the current measuring device 1 of the present embodiment, An in-plane current density distribution can be measured.

  Here, the structure of one current measurement unit 2a in the measurement plate 2 will be described with reference to FIGS. FIG. 5 is a top view of the first insulating layer 201 in FIGS. 3 and 4, in which the first electrode 211 on the surface of the first insulating layer 201 is omitted.

  As shown in FIGS. 3 and 4, the measurement plate 2 is composed of a multilayer substrate in which a plurality of insulating layers are stacked. The insulating layer is a resin layer mainly composed of a thermoplastic resin. In the present embodiment, the multilayer substrate includes three insulating layers, the first insulating layer 201, the second insulating layer 202, and the third insulating layer 203, which are stacked in this order from the top in FIGS. .

  The current measuring unit 2a includes a flat plate-like first electrode 211 and a flat plate-like second electrode 212 disposed on both surfaces of the multilayer substrate, a resistor 220 disposed inside the multilayer substrate, and an interior of the multilayer substrate. The first signal line 231 and the second signal line 232 are arranged at the same position.

  The first electrode 211 is one surface facing one of the adjacent cells 10a in the multilayer substrate so that the current measuring unit 2a is disposed between the adjacent cells 10a so as to contact one of the adjacent cells 10a. Is formed. The 1st electrode 211 is comprised by the conductor pattern (conductor layer) formed in the single side | surface (upper surface in FIG. 3) of the 1st insulating layer 201 located outside among several insulating layers. Note that the surface 211a of the first electrode 211 is in contact with one of the adjacent cells 10a.

  The second electrode 212 is opposed to the other of the adjacent cells 10a in the multilayer substrate so that the second electrode 212 is in contact with the other of the adjacent cells 10a in a state where the current measuring unit 2a is disposed between the adjacent cells 10a. Formed on the surface. The second electrode 212 is composed of a conductor pattern (conductor layer) formed on one surface (the lower surface in FIG. 3) of the third insulating layer 203 located on the outer side among the plurality of insulating layers. Note that the surface 212a of the second electrode 212 is in contact with the other of the adjacent cells 10a.

  The resistor 220 is configured by a resistance member having a resistance value larger than that of the first and second electrodes 211 and 212, and is electrically connected to both the first electrode 211 and the second electrode 212. The resistor 220 is formed by embedding resistor members 221a, 222a, and 223a constituting the resistor 220 in via holes 201a, 202a, and 203a formed in the insulating layers 201, 202, and 203, respectively. The via holes 201a, 202a, and 203a are through holes that penetrate both surfaces of the first, second, and third insulating layers 201, 202, and 203, respectively.

  As shown in FIG. 5, in this embodiment, there is one via hole for forming a resistor formed in one insulating layer. For example, one via hole 201a for forming a resistor is formed in the first insulating layer 201. The opening shape of the via hole 201a formed in the first insulating layer 201 is elliptical. For this reason, the opening shape of the via hole 201a is such that the first opening width L1 in the first direction (in this embodiment, the major axis direction of the ellipse) is the second direction (in this embodiment) orthogonal to the first direction. , A long shape longer than the second opening width L2 in the direction of the minor axis of the ellipse. The same applies to the via holes 202a and 203a of the second insulating layer 202 and the third insulating layer 203.

  Also, as shown in FIG. 3, the via holes 201a, 202a, 203a formed in the insulating layers 201, 202, 203 are the same in the direction parallel to the surfaces 211a, 212a of the first and second electrodes 211, 212. Placed in position. Therefore, the resistance members 221a, 222a, and 223a embedded in the via holes 201a, 202a, and 203a of the insulating layers 201, 202, and 203 are in a direction perpendicular to the surfaces 211a and 212a of the first and second electrodes 211 and 212. They are connected (see FIG. 4).

  The resistance member 221a formed on the first insulating layer 201 is directly connected to the first electrode 211, and the resistance member 223a formed on the third insulating layer 203 is directly connected to the second electrode 212. Yes. In addition, the resistance member 221a formed on the first insulating layer 201 and the resistance member 222a formed on the second insulating layer 202 are conductor patterns 233 formed on one surface (the upper surface in FIG. 3) of the second insulating layer 202. Connected through. The resistance member 222a formed on the second insulating layer 202 and the resistance member 223a formed on the third insulating layer 203 are directly connected.

  Therefore, the resistor 220 of the present embodiment is disposed so as to extend in a direction perpendicular to the surfaces 211a and 212a of the first and second electrodes 211 and 212. That is, the resistor 220 is arranged so that the current flows in the direction perpendicular to the surfaces 211 a and 212 a of the first and second electrodes 211 and 212 in the resistor 220.

  The first and second signal lines 231 and 232 are used to extract the potential difference between the first and second electrodes 211 and 212 to the outside of the current measuring unit 2a. The first signal line 231 and the second signal line 232 are configured by a conductor pattern (conductor layer) formed on one surface (upper surface in FIG. 3) of the second insulating layer 202. Accordingly, the first and second signal lines 231 and 232 extend in parallel with the surfaces 211a and 212a of the first and second electrodes 211 and 212 between the first and second electrodes 211 and 212, respectively. Are arranged.

  The first signal line 231 is connected to the first electrode 211 via the connection member 221b filled in the first signal line via hole 201b formed in the first insulating layer 201, separately from the resistor forming via hole 201a. And are electrically connected. The opening shape of the first signal line via hole 201b is a perfect circle (see FIG. 5).

  The second signal line 232 is a connecting member filled in the second signal line via holes 202b and 203b formed in the second and third insulating layers 202 and 203 separately from the resistor forming via holes 202a and 203a. The second electrode 212 is electrically connected through 222b and 223b. The opening shape of the second signal line via holes 202b and 203b is a perfect circle. In the present embodiment, the first signal line 231 and the first electrode 211 are connected by the connecting member 221b filled in one via hole 201b, but the connecting member filled in two or more via holes 201b. It is preferable to connect by 221b. The same applies to the connection between the second signal line 232 and the second electrode 212.

  The measuring plate 2 having the current measuring unit 2a having such a structure is manufactured as follows.

  First, a plurality of insulating layers 201, 202, and 203 each having a conductor pattern made of a conductor foil such as a copper foil are prepared.

  At this time, the first insulating layer 201 has the first electrode 211 formed on one surface thereof. Further, a via hole 201a for forming a resistor and a via hole 201b for a first signal line are formed in the first insulating layer 201 by laser processing. These via holes 201a and 201b are filled with a conductive paste. The conductive paste is composed of metal particles and a solvent. The conductive paste becomes the resistance member 221a and the connection member 221b by sintering the metal particles at the time of heating and pressing described later. For example, when tin particles and silver particles are used as the metal particles, the resistance member 221a and the connection member 221b are configured by an alloy of silver and tin. In addition, you may use a tin particle and a copper particle as a metal particle, In this case, the resistance member 221a and the connection member 221b are comprised with the alloy of copper and tin.

  Similarly, the second insulating layer 202 has first and second signal lines 231 and 232 and a conductor pattern 233 formed on one surface thereof. Further, a via hole 202a for forming a resistor and a via hole 202b for a second signal line are formed in the second insulating layer 202 by laser processing. These via holes 202a and 202b are filled with the conductive paste described above.

  Similarly, the 3rd insulating layer 203 has the 2nd electrode 212 formed in the single side | surface. Further, a via hole 203a for forming a resistor and a via hole 203b for a second signal line are formed in the third insulating layer 203 by laser processing. These via holes 203a and 203b are filled with the conductive paste described above.

  Then, a plurality of insulating layers 201, 202, and 203 are stacked to form a stacked body. At this time, the first insulating layer 201 and the second insulating layer 202 are stacked such that the resistance member 221a of the first insulating layer 201 and the conductor pattern 233 of the second insulating layer 202 face each other. The second insulating layer 202 and the third insulating layer 203 are laminated with the resistance members 222a and 223a of the second and third insulating layers 202 and 203 facing each other.

  Then, a multilayer substrate is shape | molded by heat-pressing a laminated body. At this time, adjacent insulating layers in the plurality of insulating layers 201, 202, and 203 are bonded to each other. In addition, the metal particles contained in the conductive paste are sintered to form the resistance members 221a, 222a, and 223a and the connection members 221b, 222b, and 223b. In the present embodiment, the first and second opening widths L1, L2 of the via holes 201a, 202a, 203a for forming the resistor are set so that the resistance value per electrode of the resistor 220 is about 100 μΩ to 1000 μΩ. Is set.

  As shown in FIG. 3, the first signal line 231 and the second signal line 232 are electrically connected to the voltage sensor 4 via an external wiring. The voltage sensor 4 is a potential difference detection unit that detects a potential difference between the first electrode 211 and the second electrode 212 in each current measurement unit 2 a and outputs a detection signal to the current detection circuit 3.

  The current detection circuit 3 shown in FIG. 2 performs an arithmetic process using the potential difference detected by the voltage sensor 4 and the resistance value between the first electrode 211 and the second electrode 212, whereby each current measurement unit of the cell 10a is processed. 2a is a calculation means for detecting the magnitude (current value) of a current flowing from one of the adjacent cells 10a per region corresponding to 2a to the other. The resistance value between the first electrode 211 and the second electrode 212 is measured in advance and stored in the current detection circuit 3. The current detection circuit 3 outputs the detected current value to the control device 50. Therefore, in the present embodiment, the voltage sensor 4 and the current detection circuit 3 constitute current detection means for detecting the magnitude of the current flowing between the first and second electrodes 211 and 212. Note that the current detection circuit 3 may have a function of detecting a potential difference. In this case, the current detection circuit 3 constitutes current detection means for detecting current.

  Next, a current measurement method by the current measurement device 1 of the present embodiment will be described. By supplying hydrogen and air to the fuel cell 10, power generation in the fuel cell 10 is started. The current generated by the power generation flows through the measurement plate 2 from one of the adjacent cells 10a with the measurement plate 2 in between. In each current measurement unit 2 a of the measurement plate 2, a current flows from one of the first and second electrodes 211 and 212 through the resistor 220 to the other.

At this time, since the current path between the first and second electrodes 211 and 212 has a predetermined resistance value (R ₁ ), the current (current value I ₁ ) flows through this current path, so that the first electrode A potential difference ΔV (ΔV = R ₁ × I ₁ ) is generated between the second electrode 212 and the second electrode 212.

  Therefore, this potential difference ΔV is taken out by the first and second signal lines 231 and 232 and detected by the voltage sensor 4. At this time, in the present embodiment, the first signal line 231 is connected to the first electrode 211 via the connection member 221b, and thus has the same potential as the first electrode 211. Similarly, since the second signal line 232 is connected to the second electrode 212 via the connection members 222b and 223b, the potential of the second signal line 232 is equal to that of the second electrode 212. For this reason, the potential difference between the first signal line 231 and the second signal line 232 is equal to the potential difference ΔV between the first electrode 211 and the second electrode 212.

  Then, the current detection circuit 3 performs a calculation process to divide the potential difference detected by the voltage sensor 4 by a resistance value stored in advance, so that the magnitude (current value) of the current that has passed through each current measurement unit 2a is calculated. Can be calculated.

  Further, the control device 50 detects the current distribution in the plane of each cell 10a based on the current value of each current measurement unit 2a obtained by the current detection circuit 3. Then, the control device 50 estimates the power generation state of the fuel cell 10 based on the detected current distribution, and performs feedback control such as control of the air supply amount and supply pressure, the hydrogen supply pressure, and the cooling water circulation amount. This improves the efficiency and reliability of the fuel cell system.

  Note that the power generation state of the fuel cell 10 described above can be estimated based on the change in the AC impedance of each cell 10a. Here, the AC impedance measurement method in the present embodiment will be briefly described. First, an alternating current having a predetermined current is applied to the fuel cell 10 using a secondary battery, a DC-DC converter, or the like. When alternating current is applied to the fuel cell 10, the current distribution input from the cell monitor 11 and the current detection circuit 3 is measured. And based on the change of the voltage value measured with the cell monitor 11, and the change of the current distribution input from the current detection circuit 3, the alternating current impedance of each cell 10a can be measured by calculation.

  Next, the current measurement device 1 of the present embodiment is compared with the current measurement device using the current measurement unit of the study example shown in FIGS. The current measuring unit J2a of the examination example is different from the current measuring unit 2a of the present embodiment in the shape of the resistor J220.

  As shown in FIGS. 6 and 7, in the current measurement unit J2a of the examination example, a plurality of via holes J201a, J202a, J203a are formed in each of the plurality of insulating layers 201, 202, 203, and resistance members J221a, J222a, By embedding J223a, a plurality of resistors J220 extending in a direction perpendicular to the surfaces 211a and 212a of the first and second electrodes 211 and 212 are formed.

  As shown in FIG. 8, the opening shape of one via hole J201a is a perfect circle shape, and the first opening width L1 in the first direction and the second opening width L2 in the second direction have the same dimension Ra ( L1 = L2 = Ra). The via hole J201a is formed by laser processing. The same applies to the via holes J202a and J203a.

  In contrast, in the current measurement unit 2a of this embodiment, each insulating layer 201, 202, 203 has only one via hole 201a, 202a, 203a for forming a resistor. The resistance members 221a, 222a, and 223a are embedded in the via holes 201a, 202a, and 203a, respectively, so that the first and second electrodes 211 and 212 extend in a direction perpendicular to the surfaces 211a and 212a. A resistor 220 is formed.

  For this reason, in the current measurement part 2a of this embodiment, the opening width of one via hole is larger than that of the current measurement part J2a of the examination example. Specifically, as shown in FIG. 5, the second opening width L2 of the via hole 201a is the same as the opening width of the via hole J201a shown in FIG. 8 (L2 = Ra), and the first opening width L1 is set to the second opening. The length is four times the width L2 (L1 = 4Ra). Therefore, the aspect ratio that is the ratio of the first opening width L1 and the second opening width L2 of the via hole 201a is 4: 1. The same applies to the via holes 202a and 203a.

  Here, when the dimensional error generated when processing the via holes 201a to 203a is the same (for example, ± 5 μm), the longer opening width is the actual dimension with respect to the design dimension of the opening width compared to the case where the opening width is shorter. The ratio occupied by the error becomes smaller.

  Therefore, according to the current measurement unit 2a of the present embodiment, since the opening width of one via hole is made larger than the current measurement unit J2a of the examination example, an error in the actual size with respect to the design size of the opening width is increased. The proportion occupied can be reduced. For this reason, variation in resistance value of the resistor due to variation in manufacturing can be reduced.

  Therefore, according to the current measurement device 1 of the present embodiment, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit J2a of the examination example.

  FIG. 9 shows a measurement result of resistance variation of the current measurement unit 2a of the present embodiment. The vertical axis in FIG. 9 indicates the rate of resistance variation, that is, the rate of variation of the overall resistance of the current measuring unit 2a. The ratio of the resistance variation is the ratio of the resistance variation (standard deviation σ) in the current measuring unit 2a in each embodiment when the resistance variation (standard deviation σ) in the current measuring unit J2a in the above-described study example is 1. Ratio).

  As shown in FIG. 9, the resistance variation in the current measurement unit 2a of the present embodiment is 0.5, and resistance variation can be reduced and the current measurement accuracy can be improved as compared with the current measurement unit J2a of the examination example. Recognize.

  Note that the opening shapes of the via holes 201a, 202a, and 203a are not limited to the elliptical shape as in the present embodiment, and the first opening width in the first direction is the second in the second direction orthogonal to the first direction. Other shapes such as a rectangle may be used as long as the shape is longer than the opening width.

(Second Embodiment)
As shown in FIGS. 10 and 11, in this embodiment, the resistor K220 of the current measurement unit 2a is different from the resistor 220 of the current measurement unit 2a of the first embodiment, and the first and second electrodes 211 and 212 are used. Each has a recess 241, 242 on its surface. Other configurations of the present embodiment are the same as those of the first embodiment.

  The resistor K220 includes a first resistance member J221a, a second resistance member J222a, a third resistance member J223a, and a conductor pattern (that is, a conductor layer) K233.

  The first resistance member J221a, the second resistance member J222a, and the third resistance member J223a are respectively embedded in the via holes J201a, J202a, and J203a whose opening shape is a perfect circle shape, like the current measurement unit J2a of the examination example. . Four via holes J201a, J202a, and J203a are formed in each of the insulating layers 201, 202, and 203, similarly to the current measurement unit J2a in the examination example.

  However, in the current measurement unit 2a of the present embodiment, unlike the current measurement unit J2a of the examination example, the first resistance member J221a, the second resistance member J222a, and the third resistance member J223a are the first and second electrodes 211. , 212 are spaced apart from each other in a direction parallel to the surfaces 211a, 212a.

  In the present embodiment, the first insulating layer 201 is a first electrode-side insulating layer with the first electrode 211 formed on the surface, and the via hole J201a is a first through hole that penetrates both surfaces of the first electrode-side insulating layer. is there. The second and third insulating layers 202 and 203 are second electrode-side insulating layers having the second electrode 212 formed on the surface, and the via holes J202a and J203a pass through both surfaces of the second electrode-side insulating layer. It is a hole. The first resistance member J221a is a first electrode side resistance member connected to the first electrode 211, and the second and third resistance members J222a and J223a are second electrode side resistance members connected to the second electrode 212. It is. Since the second and third resistance members J222a and J223a are linearly connected, they can be regarded as one resistance member. The second and third insulating layers 202 and 203 can be regarded as one insulating layer because one resistance member J222a and J2223a connected in a straight line is formed.

  The second and third resistance members J222a and J223a are connected to each other via a conductor pattern K233 formed on one surface (the upper surface in FIGS. 10 and 11) of the second insulating layer 202. For this reason, the conductor pattern K233 is different in shape from the conductor pattern 233 of the current measurement unit J2a of the study example, and has a larger area than the conductor pattern 233 of the study example.

  In the current measurement unit 2 a of this embodiment, the first recess 241 is provided on the surface 211 a of the first electrode 211, and the second recess 242 is provided on the surface 212 a of the second electrode 212. In the present embodiment, the first recess 241 has a depth that penetrates the first insulating layer 201 and reaches the conductor pattern K233 on the surface of the second insulating layer 202. The second recess 242 has a depth that penetrates through the third insulating layer 203 and reaches the second insulating layer 202.

  The first recess 241 is formed on the surface 211a of the first electrode 211 when the second and third resistance members J222a and J223a are projected onto the surface 211a of the first electrode 211 in a direction perpendicular to the surface 211a of the first electrode 211. Is provided at a position overlapping the region R1 of the second and third resistance members J222a and J223a projected on. The second recess 242 is projected on the surface 212a of the second electrode 212 when the first resistance member J221a is projected onto the surface 212a of the second electrode 212 in a direction perpendicular to the surface 212a of the second electrode 212. It is provided at a position overlapping the region R2 of the one resistance member J221a.

  The current measurement unit 2a of the present embodiment includes the first recess 241 so that when the current measurement unit 2a receives pressure from the second electrode 212 side, the second and third resistance members of the current measurement unit 2a are provided. The portion where J222a and 223a are formed can be bent toward the first electrode 211 side. Thereby, when the 2nd electrode 212 and the cell 10a are made to contact, the surface pressure which the 2nd electrode 212 receives can be approached uniformly.

  Similarly, the current measurement unit 2a of the present embodiment has the second recess 242 so that when the current measurement unit 2a receives pressure from the first electrode 211 side, the first resistance member of the current measurement unit 2a. The portion where J221a is formed can be bent toward the second electrode 212 side. Thereby, when the 1st electrode 211 and the cell 10a are made to contact, the surface pressure which the 1st electrode 211 receives can be closely approached uniformly.

  For this reason, it is possible to reduce variations in contact resistance that occur when the first electrode 211 and the second electrode 212 are brought into contact with the cell 10a. Specifically, as shown in FIG. 9, the resistance variation of the entire resistance including the contact resistance in the current measuring unit 2a of the present embodiment can be set to 0.25.

  Therefore, according to the current measurement device 1 of the present embodiment, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit J2a of the examination example.

(Third embodiment)
As shown in FIGS. 12 and 13, in the present embodiment, the resistor L220 of the current measuring unit 2a is different from the resistor 220 of the current measuring unit 2a of the first embodiment, and the first and second electrodes 211 and 212 are used. The first and second recesses 241 and 242 are provided on the respective surfaces. Other configurations of the present embodiment are the same as those of the first embodiment.

  The resistor L220 includes a first resistance member 221a, a second resistance member 222a, a third resistance member 223a, and a conductor pattern (that is, a conductor layer) K233.

  The first resistance member 221a, the second resistance member 222a, and the third resistance member 223a are embedded in the via holes 201a, 202a, and 203a having elliptical openings, respectively, as in the current measurement unit 2a of the first embodiment. Yes. The via holes 201a, 202a, and 203a are respectively formed in the insulating layers 201, 202, and 203 in the same manner as the current measurement unit 2a of the first embodiment. As in the second embodiment, the first resistance member 221a and the second and third resistance members 222a and 223a are mutually connected in a direction parallel to the surfaces 211a and 212a of the first and second electrodes 211 and 212. They are spaced apart.

  The conductor pattern K233 connects the first resistance member 221a and the second and third resistance members 222a and J223a to each other, as in the second embodiment.

  In the present embodiment, the first insulating layer 201 is a first electrode side insulating layer, and the via hole 201a is a first through hole. The second and third insulating layers 202 and 203 are second electrode side insulating layers, and the via holes 202a and 203a are second through holes. The first resistance member 221a is a first electrode side resistance member, and the second and third resistance members 222a and 223a are second electrode side resistance members.

  As in the second embodiment, the first recess 241 is formed when the second and third resistance members 222a and 223a are projected onto the surface 211a of the first electrode 211 in a direction perpendicular to the surface 211a of the first electrode 211. The second and third resistance members 222a and 223a projected on the surface 211a of the first electrode 211 are provided at positions overlapping the region R1.

  Similar to the second embodiment, the second recess 242 is formed when the first resistance member 221a is projected onto the surface 212a of the second electrode 212 in a direction perpendicular to the surface 212a of the second electrode 212. It is provided at a position overlapping the region R2 of the first resistance member 221a projected on the surface 212a of the first resistor 212a.

  Therefore, according to this embodiment, there are both the effects of the first embodiment and the effects of the second embodiment. In addition, as shown in FIG. 9, the resistance variation of the whole resistance including the contact resistance in the current measurement unit 2a of the present embodiment was 0.25.

(Fourth embodiment)
As shown in FIGS. 14 and 15, the current measurement unit 2 a of the present embodiment is a conductor that connects the first resistance member 221 a and the second and third resistance members 222 a and 223 a in the current measurement unit 2 a of the third embodiment. The shape of the pattern M233 is changed.

  That is, the resistor M220 of the current measuring unit 2a of the present embodiment includes the first resistance member 221a, the second resistance member 222a, the third resistance member 223a, and the conductor pattern M233. The resistor M220 corresponds to the resistor 220 of the first embodiment.

  The conductor pattern M233 is connected to the first connection region M1 that is connected to the first resistance member 221a that is the first electrode side resistance member, and the second and third resistance members 222a and 223a that are the second electrode side resistance member. A region sandwiched between the second connection regions M2 is a non-formation region M3 of the conductor pattern M233.

  As shown in FIG. 16, in this embodiment, the planar shape of the conductor pattern M233 is a square shape. Further, the length in the first direction of the non-formation region M3 of the conductor pattern M233 is the same as the length in the first direction of the first and second connection regions M1 and M2.

  In the conductor pattern M233 of the present embodiment, when a current flows from the first connection region M1 to the second connection region M2, a current flows around the non-formation region M3. On the other hand, as shown in FIG. 17, in the conductor pattern K233 of the third embodiment, the current from the first connection region M1 to the second connection region M2 is linear in the second direction so that the current path length is the shortest. It flows in a shape. For this reason, according to the conductor pattern M233 of the present embodiment, the current path between the first connection region M1 and the second connection region M2 can be made longer than the conductor pattern K233 of the third embodiment, and the conductor pattern The resistance value of M233 can be increased.

  As described above, according to the present embodiment, the region sandwiched between the first connection region M1 and the second connection region M2 is the non-formation region M3 of the conductor pattern, and thus the first connection region M1 and the second connection region. The resistance value of the conductor pattern M233 can be increased as compared with the case where the entire region sandwiched between M2 is the conductor pattern formation region. For this reason, the resistance value of the entire current path between the first electrode 211 and the second electrode 212 including the resistor M220 and the conductor pattern M233 can be increased.

  Here, when the resistance values of the resistance members 221a, 222a, and 223a constituting the resistor are compared under the same condition, the resistance member 221a with respect to the resistance value of the entire current path increases as the resistance value of the entire current path increases. , 222a and 223a account for a small proportion of error.

  Therefore, according to the present embodiment, it is possible to reduce variations in the resistance value of the entire current path by increasing the resistance value of the entire current path without changing the resistance values of the resistance members 221a, 222a, and 223a. Specifically, as shown in FIG. 9, the resistance variation of the entire resistance including the contact resistance in the current measurement unit 2a of the present embodiment can be set to 0.2. Therefore, according to the current measurement device 1 of the present embodiment, the current measurement accuracy can be improved as compared with the current measurement device using the current measurement unit J2a of the examination example.

  In addition, the length in the 1st direction of the non-formation area | region M3 of the conductor pattern M233 can be changed arbitrarily. If at least a part of the region sandwiched between the first connection region M1 and the second connection region M2 of the conductor pattern M233 is the non-formation region M3 of the conductor layer, the non-formation region M3 of the conductor pattern M233 in the first direction. The length may be shorter or longer than the length of the first and second connection regions M1 and M2 in the first direction.

(Fifth embodiment)
As shown in FIGS. 18 and 19, in the present embodiment, the resistor N220 of the current measuring unit 2a is different from the resistor 220 of the current measuring unit 2a of the first embodiment. Other configurations of the present embodiment are the same as those of the first embodiment.

  The resistor N220 includes a first resistance member J221a, a second resistance member J222a, a third resistance member J223a, and a conductor pattern M233.

  The first resistance member J221a, the second resistance member J222a, and the third resistance member J223a have the same shape and arrangement as the first resistance member J221a, the second resistance member J222a, and the third resistance member J223a of the second embodiment. It is.

  The conductor pattern M233 has the same shape as the conductor pattern M233 of the fourth embodiment. In the present embodiment, the first connection region M1 of the conductor pattern M233 is a continuous region including the connection portions with the four first resistance members 221a. Similarly, the second connection region M2 of the conductor pattern M233 is a continuous region including the connection portions with the four second resistance members 222a. For this reason, also in this embodiment, there exists an effect similar to 4th Embodiment.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope described in the claims as follows.

  (1) In each of the above embodiments, the measurement plate 2 is disposed between the adjacent cells 10a, and both the first and second electrodes 211 and 212 of the current measurement unit 2a are in contact with the cell 10a facing each other. However, the measurement plate 2 may be arranged at the end in the stacking direction among the stacked cells 10a. In this case, one of the first and second electrodes 211 and 212 of the current measuring unit 2a is in contact with the cell 10a, and the other of the first and second electrodes 211 and 212 is in contact with the current collector plate.

  (2) In each of the above embodiments, the via holes 201a to 203a and J201a to J203a are formed by laser processing, but processing other than laser processing, for example, a via hole may be formed.

  (3) In the second to fourth embodiments, both the first recess 241 and the second recess 242 are provided, but only one of them may be provided.

  (4) In the fourth and fifth embodiments, the planar shape of the conductor pattern M233 is a square shape, but may be changed to a U shape as shown in FIG. In the conductor pattern O233 shown in FIG. 20, two U-shaped portions are arranged to face each other.

  (5) The above-described embodiments are not irrelevant to each other, and can be appropriately combined unless the combination is clearly impossible. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes.

DESCRIPTION OF SYMBOLS 1 Current measuring apparatus 2a Current measuring part 220 Resistor 201 1st insulating layer (insulating layer)
201a Via hole (through hole)
202 2nd insulating layer (insulating layer)
202a Via hole (through hole)
203 3rd insulating layer (insulating layer)
203a Via hole (through hole)
221a Resistance member (first electrode side resistance member)
222a Resistance member (second electrode side resistance member)
223a Resistance member (second electrode side resistance member)

Claims (2)

A current measuring unit (2a) for measuring a current flowing through a fuel cell (10) in which a plurality of cells (10a) are stacked;
A flat plate-like first electrode (211), a flat plate-like second electrode (212) arranged opposite to the first electrode, and the first and second electrodes, the first, A current measurement unit having a resistor (220, L220, M220) electrically connected to the second electrode, wherein at least one of the first and second electrodes is in contact with the cell;
Current detection for detecting a current flowing between the first and second electrodes based on a potential difference between the first and second electrodes and a resistance value of a current path between the first and second electrodes. Means (3, 4),
The current measuring unit includes an insulating layer (201, 202, 203) disposed between the first and second electrodes,
The resistor is constituted by a resistance member (221a, 222a, 223a) embedded in a through hole (201a, 202a, 203a) formed through both surfaces of the insulating layer,
The opening shape of the through hole, Ri first second long elongated shape der than the opening width (L2) in the second direction it is perpendicular to the first direction of the opening width (L1) in a first direction ,
The insulating layer includes a first electrode side insulating layer (201) having the first electrode formed on the surface and a second electrode side insulating layer (202, 203) having the second electrode formed on the surface. ,
The resistance member is embedded in a first through hole (201a) as the through hole penetrating both surfaces of the first electrode side insulating layer, and is connected to the first electrode side resistance member (221a). And second electrode side resistance members (222a, 223a) embedded in second through holes (202a, 203a) as the through holes penetrating both surfaces of the second electrode side insulating layer and connected to the second electrode. ) And
The first and second electrode-side resistance members are spaced apart from each other in a direction parallel to the surfaces of the first and second electrodes, and the first electrode-side insulating layer and the second electrode-side insulating layer Are connected to each other through conductor layers (K233, M233) formed between
The current measuring unit has at least one of a first recess (241) provided on the surface of the first electrode and a second recess (242) provided on the surface of the second electrode,
The first recess is projected on the surface of the first electrode when the second electrode side resistance member is projected on the surface of the first electrode in a direction perpendicular to the surface of the first electrode. Provided at a position overlapping the region (R1) of the two-electrode-side resistance member,
The second recess is projected on the surface of the second electrode when the first electrode side resistance member is projected on the surface of the second electrode in a direction perpendicular to the surface of the second electrode. current measuring device according to claim Rukoto provided in a position overlapping the region (R2) of the first electrode side resistor member. The conductor layer (M233) includes a first connection region (M1) connected to the first electrode side resistance member, and a second connection region (M2) connected to the second electrode side resistance member, The current measuring device according to claim 1 , wherein at least a part of a region sandwiched between the first connection region and the second connection region is a non-formation region (M3) of the conductor layer.

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