JP2002270206A - Conductivity inspection method of fuel cell cooling liquid, structure of inspection terminal and inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp simply and precisely the conductivity of a cooling liquid that flows in the cooling liquid circulation line. SOLUTION: This method is provided for inspecting the conductivity of a cooling liquid that flows in a cooling liquid circulation line 5 that connects the fuel cell 3 and a heat exchange means 4. By this method, conductivity of a cooling liquid in a closed branch tube part 9 that is made by branching a part of the cooling liquid circulation line 5 and closing its top end is inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the conductivity of a fuel cell coolant flowing through a fuel cell, an inspection terminal structure, and an inspection apparatus.

[0002]

2. Description of the Related Art In general, as shown in FIG. 7, a fuel cell 50 has a hydrogen permeable membrane 51 and catalyst electrodes 52 on both sides thereof.
An electrode membrane structure (MEA) 56 composed of a plurality of unit cells 59 is sandwiched between a pair of separators 57 and 58 via gas diffusion layers 54 and 55 to form a plurality of unit cells 59. Gas diffusion layers 54 and 55 of each unit cell 59
Defines an anode gas channel 60 through which a fuel gas (eg, hydrogen gas) flows and a cathode gas channel 61 through which an oxidizing gas (eg, air containing oxygen) flows. The fuel gas guided into the anode gas diffusion layer 54 is ionized on the electrode reaction surface of the catalyst electrode 52. Thus, the extracted electrons can be used as DC electric energy.

In each of the separators 57 and 58, a cooling liquid flow path 62 for passing a cooling liquid (for example, pure water) for absorbing heat generated when the fuel gas is ionized penetrates the separators 57 and 58. It is defined. In addition, adjacent separators 57 of adjacent unit cells 59,
Between 58, there is formed a coolant flow groove 63 communicating with the coolant channel 62.

[0004] These coolant flow channels 62 and coolant flow grooves 63 are formed in adjacent separators 5 of adjacent unit cells 59.
Sealed to the outside by a waterproof seal 64 disposed between the cells 7 and 58 and a waterproof and insulating pole seal 65 disposed between the separators 57 and 58 of each unit cell 59. FIG. 8 shows the cooling liquid flow path 62 of each unit cell 59.
As shown in the figure, the radiator 66 outside the fuel cell 50
Coolant circulation line 6 for circulating coolant between
7 is connected. The cooling liquid heated in the unit cell 59 enters the radiator 66 through the cooling liquid circulation line 67, and after being cooled there, can flow through the cooling liquid flow path 62 in the unit cell 59 again. I have.

In this case, the coolant circulation line 67
The coolant circulated through the inside is always in contact with the channel wall surface of the coolant channel 62 in the unit cell 59, the channel wall surface in the radiator 66, and the like. These channel walls are made of a metal having high thermal conductivity in order to ensure high heat dissipation performance. For this reason, the coolant is supplied to the coolant circulation line 67.
As the coolant circulates, metal ions dissolve into the coolant from these metal parts, and the conductivity of the coolant increases.

Further, since the space between the flow path wall of the unit cell 59 and the coolant is not electrically insulated, the coolant circulation line 6 is not electrically insulated.
The rise in the conductivity of the coolant flowing through the separator 7 means that the separator 57, 58 electrically insulated by the inter-electrode seal 65 is electrically connected to the separator 57, 58 via the coolant. Cause a phenomenon. This liquid junction phenomenon, as schematically shown in FIG.
This is equivalent to connecting between the resistors 7 and 58 by the resistor 68.

When the conductivity of the coolant increases in the presence of such a liquid junction phenomenon, bubbles are generated due to the electrolysis of the coolant, causing the coolant flow groove 63 in the unit cell 59 to be closed. A weak current is generated along the coolant circulation line 67. The generation of electric current along the coolant circulation line 67 causes power loss of the fuel cell due to heat generation of the coolant circulation line 67, and also has a disadvantage that the ground level is fluctuated and adversely affects the operation of the control device and other electronic devices. Conceivable. Therefore, it is necessary to keep the conductivity of the cooling liquid as low as possible. Conventionally,
In order to suppress an increase in the conductivity of the coolant, an ion removal filter 69 is arranged at a position in the middle of the coolant circulation line 67 to remove metal ions that have melted from a flow path in the radiator 66 or the like. .

Since the ion removal performance of the ion removal filter 69 decreases with use, the conductivity of the coolant is periodically measured using a dedicated conductivity meter in order to maintain the minimum ion removal performance. In other words, the ion removal filter 69 is replaced based on the measurement time, the usage time of the ion removal filter 69, the traveling distance of the vehicle equipped with the fuel cell 50, and the like.

[0009]

However, when a dedicated conductivity meter is used, several measurement conditions are required to increase the reliability of the measurement data. One is to stop the circulation of the coolant in order to stabilize the state of the measurement. This is performed in order to avoid the influence of bubbles generated on the surface of the measurement electrode permanently provided in the cooling liquid circulation line 67 and eddies generated by the flow of the cooling liquid. Another one
One is to eliminate the voltage distribution at the measurement site. This is performed so that the measurement can be performed only with the voltage generated from the conductivity meter by eliminating the external voltage application element. Many preparatory operations are required to satisfy these measurement conditions, so that there is an inconvenience that much time is required for maintenance.

On the other hand, when the ion removal filter 69 is replaced based on the use time or the traveling distance, the ion removal performance is actually reduced so much for the purpose of maintaining the minimum ion removal performance. There is a disadvantage that the ion removing filter 69 is replaced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is capable of easily and accurately determining the conductivity of a coolant flowing through a coolant circulation line. It is an object to provide a method, an inspection terminal structure and an inspection apparatus.

[0012]

In order to achieve the above object, the present invention employs the following means. The invention described in claim 1 is a method for testing the conductivity of a fuel cell coolant flowing through a fuel cell coolant circulation line that connects a fuel cell and a heat exchange means (for example, the radiator 4 in the embodiment). A fuel cell cooling system, wherein a closed branch pipe portion is provided in which at least a part of the coolant circulation line is branched and the tip is closed, and the conductivity of the coolant is inspected in the closed branch pipe portion. A method for testing the conductivity of liquid is proposed.

[0013] According to the conductivity inspection method of the present invention,
Since the conductivity is inspected in the closed branch pipe portion formed by branching the coolant circulation line and closing the tip, the inspection result does not have to be affected by the flow of the coolant flowing through the coolant circulation line. That is, a part of the coolant flowing through the coolant circulation line flows into the closed branch pipe portion whose tip is closed and temporarily stays there, so that the inspection result does not fluctuate due to the flow. In addition, since the closed branch pipe portion communicates with the coolant circulation line at the base end, a part of the coolant flowing in the coolant circulation line flows constantly and is gradually replaced. Therefore, the conductivity inspection method according to the present invention makes it possible to stably inspect the conductivity of the coolant flowing in the coolant circulation line.

According to a second aspect of the present invention, there is provided an apparatus for inspecting the conductivity of a fuel cell coolant flowing through a fuel cell coolant circulation line connecting a fuel cell and heat exchange means, wherein at least the coolant circulation line has It is assumed that an occluded branch pipe part is formed by partially branching and closing the tip, and at least a pair of electrodes (for example, the electrodes 11 and 12 in the embodiment) are arranged in the occluded branch pipe part. A characteristic test structure of conductivity of fuel cell coolant is proposed.

According to the conductivity testing terminal structure of the present invention, the conductivity measuring means is connected to the electrode of the closed branch pipe portion,
By applying a voltage to the coolant disposed between the electrodes and measuring the conductivity of the coolant, the conductivity of the coolant can be inspected. In this case, since the measurement is performed in the closed branch pipe portion in which the coolant is retained, the conductivity can be stably inspected without being disturbed by the pulsation of the coolant circulation line. Further, when the conductivity needs to be inspected, the conductivity of the coolant can be inspected simply and inexpensively by connecting the conductivity measuring means to the electrodes.

According to a third aspect of the present invention, in the fuel cell coolant conductivity test terminal structure according to the second aspect, the base end of the closed branch pipe is formed in a radial direction of a cross section of the flow path of the cooling liquid circulation line. , The inspection terminal structure (for example, the inspection terminal structure 1C in the embodiment) characterized by being arranged in the horizontal direction or upward from the horizontal.

According to the inspection terminal structure of the present invention, the base end portion of the closed branch pipe is disposed horizontally or upward in the radial direction of the cross section of the flow path of the coolant circulation line. Impurities contained in the cooling liquid flowing through the cooling liquid circulation line, precipitates generated in the cooling liquid, and the like do not accumulate in the closed branch pipe portion, and it is possible to prevent a decrease in inspection accuracy.

According to a fourth aspect of the present invention, there is provided a fuel cell coolant conductivity test terminal structure according to the second or third aspect, wherein the electrode closer to the base end of the closed branch pipe portion (for example, Test terminal structure (for example, the electrode 12 in the embodiment) is connected to the ground of the control device of the fuel cell.
An inspection terminal structure 1) according to the embodiment is proposed.

According to the inspection terminal structure of the present invention, the electrode near the base end of the electrodes arranged in the closed branch pipe portion is connected to the ground of the control device of the fuel cell, so that the conductivity measuring portion Can be electrically disconnected from the coolant circulation line. That is, in the coolant circulation line,
With the increase in the conductivity of the coolant, a potential distribution is generated along the longitudinal direction, and the measured value of the conductivity may fluctuate due to the potential distribution. Therefore, if the base electrode close to the coolant circulation line is connected to the ground, it is possible to inspect the conductivity of the coolant without being affected by the potential distribution of the coolant circulation line.

According to a fifth aspect of the present invention, there is provided an ion removing means (for example, an ion removing means) comprising the fuel cell cooling liquid conductivity test terminal structure according to any one of the second to fourth aspects arranged in a cooling liquid circulation line. An inspection terminal structure (for example, the inspection terminal structure 30 in the embodiment) disposed upstream and downstream of the ion removal filter 7) in the embodiment is proposed.

According to the inspection terminal structure of the present invention, it is possible to conduct the conductivity inspection upstream and downstream of the ion removing means, and to compare the inspection results to grasp the ion removing performance of the ion removing means. It is possible to do. That is, unlike the method of recording the inspection result in one inspection terminal structure and indirectly determining the replacement time of the ion removing means by knowing the increase in the conductivity by comparing with the past inspection result, It is possible to immediately judge whether or not the ion removing means needs to be replaced at the time of inspection, without depending on past inspection results.

According to a sixth aspect of the present invention, there is provided an electric conductivity test terminal structure for a fuel cell coolant according to any one of the second to fifth aspects, and an electrode connected to the electrode of the test terminal structure. (Refer to, for example, the insulation resistance meter 16 in the embodiment) for measuring the insulation resistance of the cooling liquid of the fuel cell. ).

According to the conductivity inspection apparatus of the present invention,
By operating the insulation resistance measuring means, the insulation resistance of the cooling liquid between the electrodes arranged in the closed branch pipe section is measured, thereby simply and stably increasing the conductivity of the cooling liquid, and necessity of replacing the ion removing means. Can be inspected.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a fuel cell coolant conductivity test terminal structure 1 according to the present embodiment includes a fuel cell 3 in which a plurality of unit cells 2 are stacked, and a coolant supplied to the fuel cell 3. A cooling liquid circulation line 5 is provided to communicate with a radiator (heat exchange means) 4 for cooling (for example, pure water). A pump 6 for circulating the coolant is provided at an intermediate position of the coolant circulation line 5.
And an ion removal filter (ion removal means) 7 that removes ions contained in the coolant by passing the coolant in the coolant circulation line 5.
The conductivity test terminal structure 1 is disposed at one location on the downstream side of the ion removal filter 7.

As shown in FIGS. 1A and 2, the conductivity test terminal structure 1 of the present embodiment branches a part of a pipe 8 constituting a coolant circulation line 5 and closes a tip thereof. A closed branch pipe section 9 formed in a state is provided. The closed branch pipe section 9 extends horizontally, for example, from a side wall of the pipe 8 constituting the coolant circulation line 5 and is closed by a closed end face 10 arranged in a vertical direction. Note that the form of the closed branch pipe section 9 is not limited to a form that extends linearly after branching from the pipe 8 as shown in FIG. 1 (a), and may be a pipe as shown in FIGS. 1 (b) and 1 (c). After branching from 8, the tip may be bent in any direction in the horizontal plane.

A pair of electrodes 11, 1 are provided inside the closed branch pipe section 9 at intervals in the longitudinal direction of the closed branch pipe section 9.
2 are arranged. The one electrode 11 is a disc-shaped electrode arranged at the center of the closed end face 10 that closes the tip of the closed branch pipe section 9. The other electrode 12 is a disk-shaped electrode arranged at the radial center of the closed branch pipe section 9 so as to face the one electrode 11. In the figure, reference numeral 13
Is a support member for holding the other electrode 12 at the radial center position of the closed branch pipe section 9, and reference numeral 14 is a ring member for fixing the support member 13 to the inner wall of the closed branch pipe section 9. is there.

To these electrodes 11 and 12, a lead 15 led out of the closed branch pipe section 9 is connected, so that an insulation resistance meter (conductivity measuring means) 16 can be connected. ing. As shown in FIG. 2, the lead 15 connected to the electrode 12 near the base end of the closed branch pipe section 9 is connected to the ground (for example, the ground) of the control device of the fuel cell 3.
(E.g., a vehicle body on which a fuel cell is mounted). The insulation resistance meter 16 is composed of, for example, a DC power supply 17 of about 500 V and an ammeter 18 connected in series. By connecting both ends to the electrodes 11 and 12, respectively, The fixed voltage applied to electrode 1
The current flowing in addition to between 1 and 12 can be read by the ammeter 18.

The operation of the thus-configured conductivity test terminal structure 1 according to the present embodiment will be described below.
According to the inspection terminal structure 1 of the present embodiment, part of the coolant circulated through the coolant circulation line 5 by the operation of the pump 6 flows into the closed branch pipe section 9. Since the distal end of the closed branch pipe section 9 is closed, the flowing coolant temporarily stays in the closed branch pipe section 9, and the electrodes 11, which are arranged at intervals in the closed branch pipe section 9. 12 are arranged.

An operator who wants to check the conductivity of the coolant connects an insulation resistance meter 16 to a lead 15 drawn out of the closed branch pipe section 9 as shown in FIG.
Is operated to measure the current value, and it is possible to know the insulation resistance value of the coolant calculated from the generated voltage and the current value of the DC power supply 17. That is, a constant voltage V generated by the operation of the DC power supply 17 is applied to the coolant between the electrodes 11 and 12 arranged opposite to each other in the closed branch pipe section 9, and the current I flowing through the coolant is measured by the ammeter 18. As a result, the insulation resistance value R = V / I is measured. The conductivity of the coolant is the reciprocal of the insulation resistance value R, and knowing the insulation resistance value R means that the conductivity is known.

Therefore, according to the conductivity test terminal structure 1 according to the present embodiment, the insulation resistance value R of the coolant can be measured by connecting the insulation resistance meter 16, so that a dedicated conductivity meter is not used. In addition, an increase in conductivity can be easily inspected. In addition, since the inspection is performed on the coolant that is guided into the closed branch pipe portion 9 and stays there at a relatively low flow rate, the pump 6 provided in the coolant circulation line 5
A stable measured value can be obtained without being affected by the pulsation caused by the operation of

Further, according to the conductivity test terminal structure 1 according to the present embodiment, the electrode 1 disposed in the closed branch pipe portion 9 is formed.
Since the electrode 12 on the base end side of the closed branch pipe section 9 is connected to the ground, the influence of the potential distribution generated in the coolant circulation line 5 is prevented. That is, as the conductivity of the coolant flowing through the coolant circulation line 5 connecting the two electrodes of the fuel cell 3 increases, a potential distribution occurs in the coolant circulation line 5 along its length direction. Since the influence of the potential distribution of the coolant circulation line 5 is cut off by connecting the electrode 12 on the base end side of the pipe portion 9 to the ground, the conductivity of the coolant between the electrodes 11 and 12 is accurately inspected. Can be.

Further, since the closed branch pipe portion 9 is provided so as to extend in the horizontal direction from the base end to the tip end,
There is no inconvenience such as deposition of impurities in the cooling liquid on the electrode 11 disposed at the tip. Therefore,
The inspection conditions of the conductivity by the electrodes 11 and 12 can be kept constant over a long period of time, and an accurate inspection can be performed.

Further, an insulation resistance meter 1 using a relatively high voltage DC power supply 17 of about 500 V as conductivity measuring means.
By using 6, a stable measurement result can be obtained even if measurement conditions such as bubbles generated on the electrode surface and the temperature of the cooling liquid change.

In the above embodiment, the closed branch pipe section 9
Although the disk-shaped electrodes 11 and 12 which are opposed to each other with an interval in the length direction are used, the present invention is not limited to this and includes the following modifications.

The first modification is, as shown in FIG.
Instead of the disk-shaped electrodes 11 and 12 shown in FIG. 2, a pair of ring-shaped electrodes 19 and 20 are arranged at intervals in the length direction of the closed branch pipe section 9. Ring-shaped electrode 1
9 and 20 are each formed in an annular shape arranged in the circumferential direction along the inner wall of the closed branch pipe section 9, and by connecting the insulation resistance meter 16 to the electrodes 19 and 20 in the same manner as in the above embodiment. The insulation resistance value of the coolant interposed between the two can be measured.

The conductivity test terminal structure 1A according to this modification example
According to the present embodiment, the same effects as those of the inspection terminal structure 1 according to the above embodiment can be obtained, and the electrodes 19 and 20 can be connected to the closed branch pipe portion 9.
By arranging along the inner wall, obstacles that hinder the flow of the coolant in the closed branch pipe section 9 can be reduced, and the replacement of the coolant in the closed branch pipe section 9 can be promoted. There is.

In the second modification, as shown in FIG.
In that it includes a pair of rod-shaped electrodes 21 and 22 that are arranged at intervals in the diametric direction of the closed branch pipe section 9.
This is different from the above embodiment and the first modification. The electrodes 21 and 22 are attached to a ring-shaped support member 23 made of, for example, an insulating material, and the ring-shaped support member 23 is fixed to the inner wall of the closed branch tube portion 9 to thereby close the closed branch tube portion 9. Are disposed facing each other. Thus, the closed branch pipe section 9 is formed by the rod-shaped electrodes 21 and 22.
The conductivity of the coolant interposed in the diametric direction is inspected.

A conductivity test terminal structure 1B according to this modification.
Also, the conductivity test terminal structure 1 according to the first modified example.
As in the case of A, obstacles that hinder the flow of the coolant in the closed branch pipe section 9 can be reduced. The rod-shaped electrode 2
Instead of 1 and 22, parallel plate-shaped or arc-shaped plate-shaped electrodes may be arranged facing each other at intervals in the diametrical direction of the closed branch pipe section 9.

The third modification is, as shown in FIG.
The base end of the closed branch pipe section 9 is disposed at a position higher than horizontal in the radial direction of the flow path cross section of the coolant circulation line 5,
Further, the present embodiment is different from the above-described embodiment and the modified example in that the closed branch pipe portion 9 extends obliquely upward from the base end toward the distal end.

The conductivity test terminal structure 1C according to this modification example
According to this, since the base end of the closed branch pipe section 9 is arranged on the upper side, impurities having a higher specific gravity than the coolant contained in the coolant flowing through the coolant circulation line 5 can be removed. Inside is prevented. Further, the impurities contained in the cooling liquid easily flow to the base end side along the pipe wall of the oblique closed branch pipe section 9. Therefore, it is also possible to prevent the impurities in the coolant from adhering to the lower pipe wall of the closed branch pipe section 9. In this case, the inclination angle α of the closed branch pipe section 9 is, for example, 30 °,
What is necessary is just to set appropriately like 45 degrees and 60 degrees. Further, the inclination angle may be 90 °, that is, the tip may extend vertically upward.

When the closed branch pipe portion 9 is configured so that its tip is directed obliquely upward or vertically upward as in the third modification, bubbles generated inside the coolant are directed toward the tip. It is possible that it accumulates. Therefore, the closed branch pipe section 9
May be a removable transparent cap or a cap with air vent. With such a configuration, there is also an advantage that the operator who has confirmed that air bubbles have accumulated through the transparent cap can perform air bleeding as needed.

Next, a fuel cell coolant conductivity test terminal structure 30 according to a second embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment,
The conductivity test terminal structure 1 according to the first embodiment described above,
1A, 1B, and 1C are denoted by the same reference numerals as those having the same configuration, and the description will be simplified.

The inspection terminal structure 30 according to the present embodiment includes the inspection terminal structures 1, 1A, 1B, and 1 according to the first embodiment.
1C on the upstream side and the downstream side of the ion removal filter 7 provided in the coolant circulation line 5, respectively.
It is configured by arranging them one by one. In the illustrated example, the conductivity inspection terminal structure 1B according to the second modification is arranged. The upstream-side inspection terminal structure 31 and the downstream-side inspection terminal structure 31 are provided with lead wires 15 to which separate insulation resistance meters 16 can be connected. Electrodes 21 and 2
The two structures may be the same or different.

According to the inspection terminal structure 30 according to the present embodiment configured as described above, the conductivity of the cooling liquid disposed both upstream and downstream of the ion removal filter 7 can be simultaneously or almost simultaneously increased. Inspection is possible.
Therefore, the ion removal performance of the ion removal filter 7 can be checked by comparing the conductivity of the coolant inspected by the upstream inspection terminal structure 31 with the conductivity inspected by the downstream inspection terminal structure 32.

That is, when the inspection results of both the upstream inspection terminal structure 31 and the downstream inspection terminal structure 32 are the same, the ion removal performance of the ion removal filter 7 is reduced, and the downstream inspection terminal structure is reduced. If the inspection result at 32 is better than the inspection result at the upstream inspection terminal structure 31, it can be confirmed that the ion removal filter 7 has properly removed ions.

The present invention also proposes a method for testing the conductivity of a fuel cell coolant for checking the conductivity in the closed branch pipe section 9. Therefore, in addition to the case where the inspection terminal structures 1, 1A, 1B, 1C, 30 according to the above-described embodiment are used, regardless of the inspection terminal structure, the closed branch pipe portion 9 is used.
And all the inspection methods for inspecting the conductivity.

The present invention also relates to the electrodes 11, 1 of the inspection terminal structures 1, 1A, 1B, 1C, 30 according to the above embodiment.
2; 19, 20; 21 and 22 have also been proposed a fuel cell coolant conductivity testing device 40 in which an insulation resistance meter 16 as conductivity measuring means is connected. Therefore, an insulation resistance meter 16 is always connected to the inspection terminal structures 1, 1A, 1B, 1C, 30 and a conductivity inspection device 40 for continuously inspecting the conductivity of the coolant is included. It is.

In the above embodiments, pure water has been described as an example of the cooling liquid. However, the present invention may be applied to a case where an arbitrary cooling liquid such as ethylene glycol is used instead.

[0049]

As is clear from the above description, the present invention has the following effects. (1) According to the method for inspecting the conductivity of a coolant of a fuel cell according to the first aspect of the present invention, the conductivity is inspected in a closed branch pipe section which is not affected by the flow of a coolant in a coolant circulation line. Thereby, the inspection can be performed stably.
That is, since the inspection is performed on the staying coolant that has little external influence such as pulsation of the pump connected to the coolant circulation line, the inspection result does not fluctuate, and an accurate inspection can be performed. (2) According to the fuel cell coolant conductivity test terminal structure according to the second aspect of the present invention, the fuel cell coolant is disposed between the electrodes simply by connecting the conductivity measuring means to the electrodes arranged in the closed branch pipe portion. The conductivity of the coolant can be checked very simply. In particular, unlike the method of indirectly estimating the conductivity based on the usage time of the coolant or the mileage of a vehicle equipped with a fuel cell, the conductivity can be directly inspected. It is possible to eliminate waste of maintenance parts and maintenance work as described above. In addition, since the inspection is performed on the coolant in the closed branch pipe portion, it is possible to perform an accurate inspection with no change in the inspection result. (3) According to the fuel cell coolant conductivity test terminal structure according to the third aspect of the present invention, it is possible to prevent impurities or precipitates floating in the coolant from accumulating or adhering inside the closed branch pipe portion. Can be prevented. Therefore, it is possible to prevent the electrode in the closed branch pipe portion from being covered or soiled by the deposit, and to maintain an inspection environment in which an accurate inspection can be performed for a long time. (4) According to the fuel cell coolant conductivity test terminal structure according to the fourth aspect of the present invention, the influence of the potential distribution occurring along the longitudinal direction on the coolant circulation line on the test result is suppressed. be able to. That is, by connecting the electrode on the proximal end side of the closed branch pipe section to the ground of the control device of the fuel cell, the electrode can be electrically disconnected from the coolant circulation line, and the coolant in the closed branch pipe section can be electrically connected to the coolant. On the other hand, an accurate conductivity test can be performed. (5) According to the fuel cell coolant conductivity test terminal structure according to the fifth aspect of the invention, the conductivity of the coolant at the upstream and downstream of the ion removal filter can be compared, and the ion of the ion removal filter can be compared. The removal performance can be quickly confirmed. Therefore, it is possible to know the exact replacement time of the ion removal filter, and it is possible to reliably suppress the increase in the conductivity of the fuel cell coolant without waste. (6) According to the fuel cell coolant conductivity inspection apparatus according to the sixth aspect of the present invention, in addition to the above-described effects, the coolant circulation line is connected by the insulation resistance measuring means connected to the electrode in the closed branch pipe portion. This has the effect of continuously monitoring the conductivity of the flowing cooling liquid.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a fuel cell cooling circuit provided with a fuel cell coolant conductivity inspection terminal structure according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the conductivity test terminal structure of FIG.

FIG. 3 is a partially cutaway perspective view showing a first modified example of the conductivity test terminal structure of FIG. 2;

FIG. 4 is a partially cut perspective view showing a second modification of the conductivity test terminal structure of FIG. 2;

FIG. 5 is a sectional view showing a third modification of the conductivity test terminal structure of FIG. 2;

FIG. 6 is a perspective view showing a fuel cell coolant conductivity test terminal structure according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram for explaining the structure of a fuel cell.

FIG. 8 is a plan view schematically showing a conventional cooling circuit including the fuel cell of FIG.

[Explanation of symbols]

1, 1A, 1B, 1C, 30 Conductivity inspection terminal structure 3 Fuel cell 4 Radiator (heat exchange means) 5 Cooling liquid circulation line 7 Ion removal filter (ion removal means) 9 Closed branch pipe section 11, 12, 19, 20 21 and 22 electrodes 16 insulation resistance meter (conductivity measuring means, insulation resistance measuring means) 40 conductivity testing device

Claims (6)

[Claims] 1. A method for testing the conductivity of a fuel cell coolant flowing through a fuel cell coolant circulation line connecting a fuel cell and a heat exchange means, wherein at least a part of the coolant circulation line is branched and A method for inspecting the conductivity of a fuel cell coolant, comprising: providing a closed branch pipe section that closes the fuel cell; and inspecting the conductivity of the fuel cell coolant in the closed branch pipe section. 2. An inspection terminal structure for inspecting the conductivity of a fuel cell coolant flowing through a fuel cell coolant circulation line connecting a fuel cell and heat exchange means, wherein at least one of the coolant circulation lines is provided. A terminal structure for inspecting the conductivity of a coolant for a fuel cell, wherein a closed branch pipe part is formed by partially branching and closing a tip, and at least a pair of electrodes are arranged in the closed branch pipe part. . 3. The cooling liquid circulation line according to claim 2, wherein the base end of the closed branch pipe is arranged horizontally or upward in the radial direction of the flow path cross section of the cooling liquid circulation line. Fuel cell coolant conductivity inspection terminal structure. 4. The fuel cell control device according to claim 2, wherein, of the electrodes, an electrode closer to a base end of the closed branch pipe portion is connected to a ground of the fuel cell control device. Inspection terminal structure of fuel cell coolant conductivity. 5. The conductivity test of a fuel cell coolant according to claim 2, wherein the coolant is disposed upstream and downstream of the ion removing means disposed in the coolant circulation line. Terminal structure. 6. The conductivity test terminal structure of a fuel cell coolant according to claim 2, and an insulation of the coolant between the electrodes connected to the electrodes of the conductivity test terminal structure. An apparatus for testing the conductivity of a coolant for a fuel cell, comprising: an insulation resistance measuring means for measuring resistance.