JP2002117884A - Electric insulation device of flow path and cooling system of fuel cell having this electric insulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an electric insulation resistance of a liquid which flows a flow path without lengthening a length of the flow path, and reducing a cross-section area in which current flows by thinning the flow path section. SOLUTION: Two or more bladed wheels 15, 15 having two or more blades 15a, 15a, and so on, used as a liquid sending part, which rotates by a liquid pressure, are prepared in the above primary side cooling liquid circulation path 4, to secure the electric insulation resistance of the liquid flowing in the flow path, which is electrically conductive. An interval at inside 14a of a revolving body accommodating part 14 of the primary side cooling liquid circulation path 4, which accommodates the above blades 15, 15 in rotating free, and the tips of two or more above blades 15, 15, is set as the interval holding the electric insulation of the cooling liquid, and the above revolving body accommodation part 14, which accommodates the above bladed wheels 15, 15, and the bladed wheels 15, 15, is constituted with a material having high electric insulation resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an electrical insulation device for a flow path for ensuring the electrical insulation resistance of a liquid flowing through the flow path and being electrically conductive, and this electrical insulation device. The present invention relates to a fuel cell cooling system.

[0002]

2. Description of the Related Art In general, a polymer electrolyte fuel cell system is configured such that a cathode electrode is partitioned on one side and a anode electrode is partitioned on the other side with a polymer electrolyte membrane (electrolyte membrane) interposed therebetween. In addition, power is generated by a chemical reaction between oxygen in supply air supplied to the cathode electrode and supply hydrogen supplied to the anode electrode, and an external load connected to the cathode electrode and the anode electrode is driven.

In FIG. 6, reference numeral 111 denotes a fuel cell cooling system. This cooling system 111 connects a primary-side coolant circulation path 114 to a coolant path 113 defined in a fuel cell 112, and a secondary-side coolant circulation path 115.
The heat exchange between the secondary coolant and the primary coolant cooled by the radiator 117 provided between the fuel cells 112 is performed by the heat exchanger 116, and the inside of the fuel cell 112 is cooled by the primary coolant cooled by the heat exchange. I do. A bypass passage 118 is formed in the primary coolant circulation passage 114 so as to bypass the primary side of the heat exchanger 116, and the heat exchanger 11
6, a thermostat valve 120 is provided in a communication portion 119 between the downstream side of the primary coolant circulation passage 114 and the bypass passage 118.
By switching to 0, the temperature of the primary side coolant is controlled to a temperature suitable for power generation of the fuel cell 112. In addition, the primary-side coolant circulation passage 114 and the secondary-side coolant circulation passage 115
Circulating pumps 121 for circulating the coolant,
A primary coolant and a secondary coolant are forcibly circulated by respective circulation pumps 121 and 122.

[0004]

In the conventional cooling system 111 for a fuel cell, a mixture of ethylene glycol and water is contained in the primary coolant and the secondary coolant in order to prevent a liquid junction. An ion exchanger 124 for processing free ions in the primary coolant is provided in a communication passage 123 that communicates the upstream and downstream sides of the heat exchanger 116 in the primary coolant circulation passage 114. Although installed, the ion processing capacity of the ion exchanger 124 has a limit over time, and periodic maintenance must be performed.

Accordingly, the present applicants have made the primary coolant circulation passage 114 a material (resin or the like) having a high electrical insulation resistance and made the primary coolant circulation passage 114 smaller in cross section. A method of obtaining a constant electrical insulation resistance,
A method of obtaining a constant electrical insulation resistance by extending the length of the primary-side coolant circulation passage 114 was examined. However, in the former method, it is difficult to secure a flow rate of the primary-side coolant, and in the latter method, Then, it is difficult to reduce the size of the device.

Therefore, in order to ensure the electrical insulation resistance of the liquid flowing through the flow path without increasing the length of the flow path and without reducing the cross section of the flow path, the liquid can be electrically conducted. A technical problem to be solved arises, and an object of the present invention is to solve this problem.

[0007]

According to the first aspect of the present invention,
In order to ensure an electrical insulation resistance of a liquid flowing through the flow path and an electrically conductive liquid, the flow path is provided with a rotating body having a plurality of liquid feed portions rotated by hydraulic pressure, and The space between the inner surface of the liquid feeder and the tip of the plurality of liquid feeders is set to be narrow, and the rotary body and the rotary body accommodating part of the flow channel that accommodates the rotary body are formed of a material having a high electrical insulation resistance. An electric insulating device is provided.

According to a second aspect of the present invention, there is provided an electrical insulating device for a flow path according to the first aspect, wherein the rotary body is provided with a rotary drive means. .

Further, the invention according to claim 3 is the invention according to claim 1.
An object of the present invention is to provide a cooling system for a fuel cell, wherein the electrical insulation device for a flow path according to the above or claim 2 is provided at at least one position in a coolant circulation passage for cooling the inside of the fuel cell.

In other words, according to the first aspect of the present invention, the rotating body which is rotated by the hydraulic pressure is sent out by a plurality of liquid sending portions, and the rotating body and the rotating body accommodating section of the flow path accommodating the rotating body are electrically connected. It is formed of a material having a high insulation resistance, and by forming a gap corresponding to the electrical insulation resistance of the liquid that can be electrically conducted between the tips of the plurality of liquid feed portions and the inner surface of the flow path, Secure electrical insulation resistance.

According to the second aspect of the present invention, a rotation driving means is attached to the rotating body. For this reason, the rotational drive means improves the rotational resistance of the rotator, controls the flow rate and pressure of the primary coolant circulation passage by controlling the rotation of the rotator,
Further, the forced circulation of the liquid by the driving of the rotation driving means becomes possible.

Further, according to the third aspect of the present invention, the electrical insulation device for the flow path according to the first aspect is provided at at least one position of a cooling liquid circulation passage for cooling the inside of the fuel cell. It is possible to prevent the liquid junction of the cooling liquid in the cooling system, and in the electric insulation device for the flow path according to the second aspect, the cooling liquid necessary for cooling the fuel cell is circulated to improve the fuel cell. Can be cooled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel cell cooling system to which a flow path electrical insulation device according to the present invention is applied will be described in detail with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a fuel cell cooling system. In the cooling system 1, an inlet and an outlet of a primary coolant circulation passage 4 are connected to an inlet and an outlet of a cooling passage 3 partitioned in a fuel cell 2, and the cooling system 3 is interposed in a secondary coolant circulation passage 5. The radiator 7 cools the secondary coolant. Then, heat is exchanged between the primary coolant and the secondary coolant by the heat exchanger 6, and the inside of the fuel cell 2 is cooled by the primary coolant cooled by the heat exchange.

A bypass passage 8 is formed in the primary coolant circulation passage 4 so as to bypass the primary side of the heat exchanger 6, and the bypass passage 8 is formed on the downstream side of the primary coolant circulation passage 4 as viewed from the heat exchanger 6. A thermostat valve 10 is provided in a communication portion 9 between the fuel cell 2 and the bypass passage 8. By switching the thermostat valve 10, the temperature of the primary coolant is controlled to a temperature suitable for power generation of the fuel cell 2. Circulation pump 1 provided in liquid circulation passage 4 and secondary coolant circulation passage 5
The primary side coolant and the secondary side coolant are forcibly circulated by 1 and 12.

In order to prevent a liquid junction of the primary side coolant (ground fault via the coolant), an electrical insulating device 13 is provided between the inlet side and the outlet side of the primary side coolant circulation path 4. 13
Is installed.

As shown in detail in FIG. 2, the electrical insulation device 13 includes a rotating body housing portion 14 formed in the middle of the primary side coolant circulation passage 4 as a flow path, and a rotating body housing portion 14. It comprises a pair of impellers 15 as rotating bodies rotatably housed therein. The rotating body housing portion 14 and a pair of impellers 15 housed in the rotating body housing portion 14;
15 is made of a material having a high electrical insulation resistance for electrical insulation, for example, a resin, and the pair of impellers 15 and 15 are rotatably engaged with each other. It is housed in the rotating body housing 14.

An inlet 16 for passing the primary coolant is formed on the upstream side of the rotator housing portion 14, and an outlet 17 for discharging the primary coolant is formed on the downstream side. And an impeller 15 as the liquid feeder,
The 15 blades 15a, 15a,...
4 is formed so as to be rotated by the pressure of the primary-side coolant moving from the inlet 16 to the outlet 17.

Further, the blades 15 of the impellers 15
, a, 15,...
4a, 14a are formed such that a clearance required for electrical insulation of the primary coolant is set, and the pitch of the blades 15a, 15a,. , 15 are rotated along the inner surfaces 14a, 14a of the rotator housing portion 14 by the pressure of the primary-side cooling liquid, the tip of at least one or more, preferably two or more blades 15a is brought into contact with the rotator housing portion 14. Inner surface 14
a, 14a so as to form the clearance.

The pair of impellers 15, 15 has at least one discharge amount necessary for circulation in a space defined by adjacent blades 15 a, 15 a and inner surfaces 14 a, 14 a of the rotator housing 14. / 2 cooling liquid can be taken in.

Hereinafter, the operation of the embodiment of the present invention will be described. As shown in FIG. 1, the primary-side coolant circulation passage 4, and
When the circulation pumps 11 and 12 of the secondary-side coolant circulation path 5 are driven, the primary-side coolant circulates through the primary-side coolant circulation path 4 and the cooling path 3, and the water of the secondary-side coolant path 5 and the radiator 7 is discharged. A secondary-side coolant circulates in a jacket (not shown).

As shown in FIGS. 1 and 2, the pressure of the primary side coolant entering the rotating body housing 14 from the inlet 16 of the rotating body housing 14 of the electrical insulating device 13 is controlled by a pair of impellers 15. , 15, the impellers 15, 15 rotate in opposite directions due to this pressure. At this time, the impellers 15, 15 are formed on the impeller shafts 15b, 15b at the above-mentioned pitch, so that at the time of rotation, the tips of at least two blades 15a, 15a and the inner surface 14a Between them, a small clearance for maintaining the electrical insulation resistance of the primary coolant is set. For this reason, the electrical insulation resistance of the primary coolant is maintained.

On the other hand, a pair of impellers 15, 15
a, and rotates while taking in at least half of the flow rate of the primary-side cooling liquid into a space defined between the first-side cooling liquid and the first-side cooling liquid. Therefore, the required flow rate circulates without setting the flow path cross section of the primary coolant to be large, and the interior of the fuel cell 2 is cooled well by the primary coolant.

FIG. 3 shows the electrical insulation resistance of the primary coolant relative to the pipe length (flow path length) L when the electrical insulation device 13 is provided in the primary coolant circulation passage 4 and when it is not provided. Indicates the size. In the figure, reference symbol R1 denotes an electrical insulating device 13
Indicates the electrical insulation resistance value of the primary-side coolant when no electrical insulation is provided, and reference numeral R2 indicates the electrical insulation resistance value of the primary-side coolant when the electrical insulation device 13 is provided.

As is apparent from FIG. 3, when the electrical insulating device 13 is provided in the primary coolant circulation passage 4,
Even if the pipe length L is the same, the electrical insulation resistance value is maintained at the electrical insulation resistance R2 necessary for electrical insulation of the primary coolant flowing in the primary coolant circulation passage 4.

For this reason, it is possible to make the coolant circulation amount of the primary coolant to a necessary flow rate without increasing the cross section of the primary coolant circulation passage 4. The electrical insulation between the upstream side and the downstream side centered at 14 is kept constant, and the upstream side and the downstream side of the primary side coolant circulation path 4, and thus the primary side circulation path 4 and the secondary side circulation path 5 are connected. It is also possible to prevent a ground fault caused by a liquid junction.

FIG. 4 shows an embodiment in which the electrical insulation device 13 can be driven as a positive displacement pump.
In this embodiment, the gear 1 is attached to the impeller shafts 15b, 15b.
8 and 19 are attached, respectively, and a motor 20 as a rotation driving means is connected to one of the impeller shafts 15b. Of course, the gears 18, 19 are meshed with each other.

Therefore, according to this configuration, the rotation resistance of the impellers 15, 15 with respect to the circulation of the primary coolant can be reduced by the rotation of the pair of impellers 15, 15. Conversely, it is also possible to control the flow rate and pressure of the primary-side coolant circulation path 4 by controlling the rotation of the impellers 15, 15 and to forcibly circulate the primary-side coolant by the rotational driving force of the motor 20. it can.

FIG. 5 shows an electrical insulating device 13a configured as a roots volume pump. In this case, the rotating body 2
The gears 18 and 19 are attached to the rotation shafts 21b and 21b of the rotation shafts 21 and 21 respectively.
A motor 20 as a rotation driving means is connected to 1b, and the gears 18, 19 mesh with each other.

The rotating body housing 22 and the pair of rotating bodies 21 and 21 rotatably housed therein are formed of a material having a high electrical insulation resistance, for example, a resin, for electrical insulation. The pair of rotating bodies 21 and 21
It is housed in the rotating body housing part 22 in a state of being engaged with each other and rotating.

The rotary body housing 22 has an inlet 23 and an outlet 24 for allowing the primary side coolant to pass therethrough, and the liquid feeders 21a, 21a, 2 of the rotary bodies 21 and 21 are formed.
1 a is configured to pump the primary-side coolant that moves from the inlet 23 to the outlet 24 of the rotator housing 22.

Then, the liquid feed portions 21a,
21a, 21a are formed such that a tip thereof sets a clearance required for electrical insulation of the primary-side coolant between the inner surface 22a of the rotator housing 22 and a pair of rotators 21, The pitch of the liquid sending portions 21a, 21a adjacent to each other is determined by the pressure of the primary side cooling liquid.
When the first and second components 21 and 21 are rotated along the inner surface 22a of the rotator housing portion 22, at least one or more, preferably two or more liquid feed portions 21a are positioned between the tip of the liquid feeder 21a and the inner surface 22a of the rotator housing portion 22. It is determined to provide the necessary clearance for electrical insulation.

Further, at least a primary coolant is required to circulate in a space defined by the liquid feed portions 21a, 21a adjacent to the pair of rotating bodies 21, 21 and the inner surface 22a of the rotating body housing 22. The primary cooling liquid is set so as to be の of the appropriate discharge amount.

Therefore, at the time of rotation, the electrical insulation resistance of the primary-side coolant is ensured between the tips of the at least two liquid feed portions 21a, 21a and the inner surface 22a of the rotator housing 22, and the adjacent liquid feed portions 21a, 21a and rotating body housing 2
At least one half of the flow rate of the primary coolant can be taken into and sent out into the space defined between the second coolant and the inner surface 22a.

As a result, it is possible to circulate the required amount of the primary coolant without setting the flow path cross section of the primary coolant to be large. Can be cooled.

Of course, the flow rate and pressure of the primary coolant circulation path 4 may be controlled by controlling the rotation of the rotating body 21 by the motor 20.

In this embodiment, an example has been described in which the electrical insulation devices 13, 13, and 13a are attached to the cooling system 1 for a fuel cell. However, the electrical insulation devices 13, 13, and 13a are used for various flow paths requiring electrical insulation. Shall be. As described above, the present invention can be variously modified without departing from the technical idea of the present invention, and it goes without saying that the present invention extends to the modified invention.

[0038]

According to the first aspect of the present invention, as described in detail in the first embodiment, the length of the flow path is not increased, and the cross section of the flow path is reduced by reducing the cross section of the flow path. This is an invention that exhibits a very great effect, such as being able to secure electrical insulation resistance of a liquid flowing through a flow path and being electrically conductive, and being able to be formed in a small size.

Further, according to the present invention, the rotational resistance of the rotator can be improved, and conversely, the flow rate and the pressure of the primary coolant circulation path can be controlled by controlling the rotation of the rotator. It has an excellent effect that the liquid can be forcibly circulated.

Further, according to the third aspect of the present invention, it is possible to prevent a liquid junction of the cooling liquid in the cooling system of the fuel cell, and to circulate and cool the cooling liquid necessary for cooling the fuel cell. It is an invention that exhibits a truly remarkable effect, for example,

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a fuel cell cooling system according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a structure of a flow path electrical insulation device according to the present invention.

FIG. 3 is a diagram showing a change in an electric resistance value by an electric insulation device for a flow channel according to the present invention.

FIG. 4 is an explanatory view showing a state in which a motor as a rotation driving means is attached to the electrical insulation device for the flow channel according to the present invention.

FIG. 5 is an explanatory view showing an embodiment in which the electrical insulating device for a flow channel according to the present invention is formed in a roots-shaped positive displacement pump shape.

FIG. 6 is an explanatory view showing a conventional example and showing a cooling system for a fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling system 2 Fuel cell 4 Primary-side cooling-fluid circulation path 15 Impeller (rotating body) 15a Blade (liquid sending part) 14 Rotating body housing part 14a Inner surface of rotating body housing part

Claims (3)

[Claims] A rotator having a plurality of liquid feed portions which are rotated by liquid pressure is provided in said flow path in order to secure an electrical insulation resistance of a liquid flowing through the flow path and being electrically conductive. In addition, the gap between the inner surface of the flow path and the tip of the plurality of liquid feed sections is set to be narrow, and the rotator and the rotator housing section of the flow path that accommodates the rotator are made of a material having a high electrical insulation resistance. An electrical insulation device for a flow path, comprising: 2. The electrical insulation device for a flow path according to claim 1, wherein a rotation driving means is attached to said rotating body. 3. The fuel cell according to claim 1, wherein the electrical insulating device for the flow path according to claim 1 or 2 is provided at least at one position of a coolant circulation passage for cooling the inside of the fuel cell. Cooling system.