JP2010182509A - Cooling system of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system of a fuel cell which rationalizes flow-rate of a cooling liquid flowing to a heat exchanger and cools the fuel cell properly by suppressing the flow-rate of the cooling liquid flowing to bypass piping and an ion exchanger during a high load operation of the fuel cell. <P>SOLUTION: Filters 21, 23 are installed inside the vessel body 19 of an ion exchanger 18 which is connected in series to a bypass piping 17 that is connected in parallel on the way of a circulation piping of the cooling system of the fuel cell, and an ion exchange resin E is housed movably in a resin housing chamber R. Flow-rate adjusting plates 27, 28 capable of elastic deformation are installed on mounting seats 25, 26 inside the resin housing chamber R, and a passage T in which the cooling liquid passes is provided between the flow-rate adjusting plates 27, 28. By a flow dynamic pressure by which the cooling liquid flows upward from the bypass piping 17, the flow-rate adjusting plates 27, 28 are elastic deformed upward, and the fuel cell is operated at a high load, and when the flow velocity of the cooling liquid is fast, the passage T of the flow-rate adjusting plates 27, 28 is reduced to decrease the flow-rate of the cooling liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling system for a fuel cell, and more particularly, to a cooling system for absorbing and cooling heat generated from a power generation cell by heat exchange during power generation of the fuel cell.

  In a fuel cell system, when power generation is performed by the reaction of hydrogen gas and oxygen gas by a plurality of power generation cells stacked in a fuel cell, the power generation cell generates heat. If this is left unattended, the power generation cell is overheated and power generation becomes impossible. For this reason, in order to cool a power generation cell at the time of power generation, a fuel cell is generally provided with a cooling system of a coolant type. As this cooling system, the one disclosed in Patent Document 1 has been proposed. The cooling system will be described with reference to FIG. 9. The fuel cell 11 is connected to a circulation pipe 12 that circulates a coolant by a pump 13. A heat exchanger 14 is connected to the circulation pipe 12 on the upstream side of the pump 13. The heat exchanger 14 includes a radiator 15 and a blower fan 16 for blowing air onto the radiator 15.

  As the cooling liquid, LLC (long life coolant) containing ethylene glycol (antifreeze) in water is used. When the pump 13 is driven at the time of power generation and the coolant is supplied to the inside of the fuel cell 11, heat is exchanged in the heat exchanger 14 due to a temperature difference between the heat generated from the power generation cell and the heat of the coolant. The power generation cell of the fuel cell 11 is cooled by the coolant. At this time, ethylene glycol contained in the coolant is thermally decomposed to produce formic acid, and negative ions are produced by the formic acid. Further, when the inner surface of the coolant circulation path is corroded by formic acid, positive ions are also generated. Thus, the cooling liquid contains impurity ions in which negative ions and positive ions are mixed. Since these ions have electric charges, the higher the concentration of impurity ions contained in the coolant, the higher the electrical conductivity of the coolant, and the electricity generated by the fuel cell 11 may leak to the outside using the coolant as a medium. There is.

  In order to cope with the above problem, in Patent Document 1, a bypass pipe 17 is connected to the circulation pipe 12 in parallel with the pump 13. An ion exchanger 18 for adsorbing and removing impurity ions contained in the coolant is connected to the bypass pipe 17. Inside the ion exchanger 18, a particulate anion type adsorbing negative ions and a particulate cation type adsorbing positive ions are accommodated as ion exchange resins. The impurity ions are adsorbed and removed by the ion exchange resin so that the electrical conductivity of the coolant does not increase.

  Patent Document 2 also discloses a cooling system similar to the fuel cell cooling system described above.

JP 2005-161117 A JP 2003-249249 A

  In the conventional cooling system for the fuel cell 11, the pump 13 is operated at a low speed during the low load operation, and the flow rate of the coolant flowing through the circulation pipe 12 is also reduced. The flow rate of the flowing coolant and the flow rate of the coolant flowing in the ion exchanger 18 are also small. Thus, even when the flow rate of the cooling liquid is small, the flow rate of the cooling liquid necessary for ion exchange by the ion exchange resin in the ion exchanger 18 is an appropriate amount.

  On the other hand, during high load operation of the fuel cell 11, the pump 13 is operated at a high speed, the flow rate of the coolant increases, and the flow rate of the coolant flowing to the heat exchanger 14 and the ion exchanger 18 also increases. However, since the excessive supply of the coolant is performed to the ion exchanger 18 having a high pressure loss, the circulation flow rate of the coolant in the entire circulation pipe 12 is reduced, and consequently flows to the heat exchanger 14. There was a problem that the flow rate of the coolant was reduced and the fuel cell 11 could not be properly cooled.

  The object of the present invention is to solve the above-mentioned problems in the prior art and suppress the flow rate of the coolant flowing through the bypass piping and the ion exchanger having a high pressure loss during the high load operation of the fuel cell. A fuel cell cooling system capable of optimizing the flow rate of the coolant flowing to the exchanger and properly cooling the fuel cell and improving the utilization efficiency of the ion exchange resin accommodated in the ion exchanger. It is to provide.

  In order to solve the above problems, the invention according to claim 1 is characterized in that a coolant circulation pipe is connected to the fuel cell, a pump for circulating the coolant is connected to the circulation pipe, and cooling in the circulation pipe is performed. A fuel in which a heat exchanger for cooling the liquid is connected, a bypass pipe is connected to the circulation pipe, and an ion exchanger for adsorbing and removing impurity ions contained in the coolant in the circulation pipe is connected to the bypass pipe In the battery cooling system, a resin storage chamber is formed between the two filters, storing the upstream filter and the downstream filter at a predetermined interval with respect to the flow direction of the coolant in the ion exchanger container. A granular ion exchange resin is movably accommodated, and a flow rate adjustment plate for adjusting the flow rate of the coolant flowing in the container is provided in the resin storage chamber, and the flow rate adjustment plate is provided during high load operation of the fuel cell. Ri is summarized in that which is configured to reduce the flow rate of the cooling fluid flowing through the vessel.

  According to a second aspect of the present invention, in the first aspect, the flow rate adjusting plate is formed of an elastically deformable plate material, and when the flow rate of the cooling liquid increases, the flow rate adjusting plate is elastically deformed by the flow of the cooling liquid. The gist is that the cross-sectional area of the coolant is reduced.

  According to a third aspect of the present invention, in the first aspect, when the temperature of the coolant in the container increases, the flow rate adjusting plate is deformed by the temperature so that the passage cross-sectional area of the coolant is reduced. The gist is that it is configured.

  According to a fourth aspect of the present invention, in the first aspect, the flow rate adjusting plate is configured such that position switching control is performed by a signal from a sensor that detects the temperature of the coolant in the circulation pipe. Is the gist.

  According to a fifth aspect of the present invention, in the first aspect, the flow rate adjusting plate is configured such that position switching control is performed by a signal from a sensor that detects a flow rate of the coolant in the circulation pipe. Is the gist.

(Function)
According to the present invention, an upstream filter and a downstream filter are accommodated in a container of an ion exchanger, an ion exchange resin is movably accommodated in a resin accommodating chamber between both filters, and the container is accommodated in the resin accommodating chamber. A flow rate adjusting plate for adjusting the flow rate of the coolant flowing inside was provided. Then, the flow rate of the coolant flowing through the ion exchanger is suppressed by the flow rate adjusting plate during high load operation of the fuel cell. For this reason, the flow rate of the coolant flowing from the circulation pipe to the heat exchanger becomes appropriate, and the fuel cell is appropriately cooled by the coolant cooled by the heat exchanger.

  In the present invention, since the flow rate adjusting plate is accommodated in the resin accommodating chamber of the ion exchanger container, the ion exchange resin is stirred and mixed by the movement of the flow rate adjusting plate. Therefore, a large number of ion exchange resins are mixed, the ion exchange action of the granular ion exchange resin is performed uniformly, and the ion exchange resin is evenly consumed. For this reason, the utilization efficiency of an ion exchange resin can be improved.

  According to the present invention, during high load operation of the fuel cell, the flow rate of the coolant flowing through the bypass pipe and the ion exchanger is suppressed, and the flow rate of the coolant flowing from the circulation pipe to the heat exchanger is optimized. The fuel cell can be properly cooled by the liquid, and the utilization efficiency of the ion exchange resin accommodated in the ion exchanger can be improved.

(A) is a longitudinal cross-sectional view of the ion exchanger which accommodated the ion exchange resin of the cooling system of the fuel cell of this invention in the low-speed operation state, (b) is a longitudinal cross-sectional view of the ion exchanger in the high-speed operation state. The cross-sectional view of an ion exchanger. 1 is a schematic circuit diagram showing a fuel cell cooling system. FIG. The longitudinal cross-sectional view of the ion exchanger which shows another embodiment of this invention. The cross-sectional view of the ion exchanger shown in FIG. The expanded longitudinal cross-sectional view of the principal part of the ion exchanger which shows another embodiment of this invention. The longitudinal cross-sectional view of the ion exchanger which shows another embodiment of this invention. The longitudinal cross-sectional view of the ion exchanger which shows another embodiment of this invention. FIG. 6 is a schematic circuit diagram showing a conventional fuel cell cooling system.

Hereinafter, an embodiment in which the present invention is embodied as a cooling system for a fuel cell of an electric vehicle will be described with reference to FIGS.
Although not shown, the fuel cell 11 shown in FIG. 3 includes a fuel electrode, an oxidant electrode, and power generation cells that are stacked in multiple layers between the two electrodes. A hydrogen gas supply system (not shown) for supplying hydrogen gas as fuel is connected to the fuel electrode side. An air supply system (not shown) for supplying air containing oxygen gas as an oxidant is connected to the oxidant electrode side. The hydrogen gas and oxygen gas supplied to each power generation cell in the fuel cell 11 react to generate power.

  A circulation pipe 12 for circulating a coolant for cooling the power generation cells of the fuel cell 11 is connected to the fuel cell 11 in a state where power generation is being performed, and a pump 13 is connected to the circulation pipe 12. Has been. In this embodiment, LLC (long life coolant) containing ethylene glycol in water is used as the coolant. A heat exchanger 14 is connected to the circulation pipe 12 on the upstream side of the pump 13 for cooling the high-temperature coolant used for cooling the power generation cells in the fuel cell 11 and heated by heat exchange. Yes. The heat exchanger 14 includes a radiator 15 connected to the circulation pipe 12 and a blower fan 16 driven by an electric motor for blowing air to the radiator 15 to cool a high-temperature coolant.

  A bypass pipe 17 is connected to the circulation pipe 12 in parallel with the pump 13. An ion exchanger 18 for adsorbing and removing impurity ions contained in the coolant is connected in series to the bypass pipe 17.

Next, the ion exchanger 18 will be described.
As shown in FIG. 1 (a), a male screw portion 19 a is formed at the upper end opening of the container body 19 of the ion exchanger 18, and a female screw portion 20 a formed on the inner peripheral surface of the lower end opening of the lid body 20. The male thread portion 19a of the container body 19 is screwed. A small-diameter joint portion 19 b for connecting the upstream bypass pipe 17 is integrally formed at the lower end portion of the container body 19. A small-diameter joint portion 20 b for connecting the downstream bypass pipe 17 is integrally formed at the upper center of the lid body 20. A filter 21 on the upstream side with respect to the flow direction of the coolant is attached to the lower end portion of the container body 19 by an attachment ring 22 on the outer periphery thereof. The outer peripheral edge of the downstream filter 23 is sandwiched and fixed between the upper end edge of the container body 19 and the stepped portion 20 c formed on the inner periphery of the lid body 20. A resin storage chamber R for storing the ion exchange resin E is formed by the inner peripheral surface of the container body 19 and the filters 21 and 23. Both the filters 21 and 23 are formed by a mesh smaller than the particle diameter of the ion exchange resin E so that the particulate ion exchange resin E does not flow out of the resin storage chamber R to the outside. As the ion exchange resin E, an anion type that adsorbs negative ions and a cation type that adsorbs positive ions are mixed and contained.

  As shown in FIG. 2, mounting seats 25 and 26 are attached to the inner peripheral surface of the container main body 19 at two locations by welding. On the two pairs of mounting seats 25 and 26, flow rate adjusting plates 27 and 28 made of an elastically deformable metal plate are attached by bolts 29. A passage T through which the coolant can flow is formed between the flow rate adjusting plates 27 and 28. The flow rate adjusting plates 27 and 28 are formed in an arc shape as shown in FIG. When the flow rate of the cooling liquid in the resin storage chamber R increases, the flow rate adjusting plates 27 and 28 are elastically deformed by the high flow pressure of the cooling liquid, as shown in FIG. By being elastically deformed in the approaching direction, the passage T becomes smaller and the flow rate of the coolant is reduced.

Next, the operation of the cooling system for the fuel cell 11 configured as described above will be described.
When the fuel cell 11 is activated by an activation signal from a controller (not shown) and various control signals, hydrogen gas and oxygen gas supplied to the fuel cell 11 react to generate power. The generated direct current is converted into an alternating current by an inverter and used to drive a motor for running an electric vehicle.

  On the other hand, when the pump 13 of the cooling system is started, the coolant in the circulation pipe 12 is circulated in the direction of the arrow in FIG. 3, and the coolant cooled by the heat exchanger 14 is supplied into the fuel cell 11, The heat generated by the power generation of the battery 11 is absorbed by the coolant, and the fuel cell 11 is cooled. The coolant that has absorbed heat and has reached a high temperature is cooled again by the heat exchanger 14 and reused for cooling the fuel cell 11.

  Since the coolant in the circulation pipe 12 is heated by the heat generated by the power generation cells in the fuel cell 11, the ethylene glycol contained in the coolant is thermally decomposed to produce positive and negative impurity ions. The A part of the cooling liquid containing the impurity ions flows into the container body 19 from the lower inlet of the ion exchanger 18 as shown in FIGS. 1A and 1B from the bypass pipe 17 and flows upward. Then, it is led from the upper outlet to the circulation pipe 12 through the bypass pipe 17. Then, negative and positive impurity ions are removed by the ion exchange resin E (anion type and cation type) in the ion exchanger 18.

According to the fuel cell cooling system of the above embodiment, the following effects can be obtained.
According to the fuel cell cooling system of the above embodiment, the following effects can be obtained.

  (1) In the above embodiment, when the flow rate adjusting plates 27 and 28 are mounted inside the container body 19 of the ion exchanger 18 and the flow rate of the coolant flowing inside the ion exchanger 18 is increased, the cooling is performed. The flow rate adjusting plates 27 and 28 are elastically deformed by the flow pressure of the liquid, and the cooling liquid passage T formed between the flow rate adjusting plates 27 and 28 is reduced. Therefore, when the fuel cell 11 is operated at a high load, the flow rate of the coolant flowing in the circulation pipe 12 is increased, and the flow rate of the coolant flowing in the bypass pipe 17 is also increased. 27 and 28 reduce the flow rate of the coolant. Accordingly, the coolant does not flow excessively in the ion exchanger 18 having a high pressure loss, and the circulation flow rate of the coolant in the circulation pipe 12 can be optimized and an appropriate amount of coolant can be supplied to the heat exchanger 14. The cooling of the fuel cell 11 with the coolant can be optimized.

  (2) In the embodiment described above, the ion exchange resin E contained in the resin containing chamber R in the container body 19 is agitated and mixed by the elastic deformation operation of the flow rate adjusting plates 27 and 28. Therefore, the ion exchange resin E is evenly consumed by the ion exchange action. Therefore, when the ion exchanger 18 is replaced, the ion exchanger 18 in which usable ion exchange resin remains is not discarded, and the utilization efficiency of the ion exchange resin E can be improved.

  (3) In the above embodiment, the flow rate adjusting plates 27 and 28 are arranged in the container main body 19 of the ion exchanger 18, so that the configuration is simplified and the manufacturing and assembling operations are facilitated. Because there are few failures, durability can be improved.

In addition, you may change the said embodiment as follows.
As shown in FIGS. 4 and 5, the flow rate adjusting plates 31 and 32 made of bimetal are attached to the mounting seats 25 and 26 provided inside the container main body 19 with bolts 29. The flow rate adjusting plates 31 and 32 are fixed in a state where a plate 33 having a small linear expansion coefficient and a plate 34 having a large linear expansion coefficient are overlapped. The flow rate adjusting plates 31 and 32 are deformed into a curved state indicated by a solid line or a linear state indicated by a two-dot chain line depending on the temperature of the coolant flowing in the bypass pipe 17 and the ion exchanger 18. The passage T is narrowed by the flow rate adjusting plates 31 and 32 during the high load operation of the fuel cell 11 in which the coolant temperature is high, and the passage T is widened during the low load operation where the coolant temperature is lowered. It is configured.

This embodiment also has the same effects as the effects (1) to (3) of the cooling system of the present embodiment described above.
As shown in FIG. 6, the arrangement structure of the flow rate adjusting plates 31 and 32 shown in FIG. 4 may be turned upside down.

As shown in FIG. 7, the mounting seats 25 and 26 may be moved closer to each other, the flow rate adjusting plates 27 and 28 may be opposed to the inner surface of the container body 19, and the passage T may be formed in two places.
As shown in FIG. 8, a flow rate adjusting plate 42 is supported on the container body 19 via a rotating shaft 41 so as to be reciprocally rotatable. Further, a motor 43 capable of rotating in the forward and reverse directions for rotating the rotary shaft 41 and the flow rate adjusting plate 42 is attached to the outer surface of the container body 19. Further, a sensor 44 that detects the temperature of the coolant in the circulation pipe 12 is provided for the circulation pipe 12. The motor 43 is configured to rotate according to a detection signal from the sensor 44. During high load operation of the fuel cell 11 with a high coolant temperature, the motor 43 is activated by a temperature detection signal from the sensor 44 and the flow rate adjusting plate 42 is displaced to a position indicated by a chain line where the passage T becomes narrow. Let On the other hand, during low load operation where the coolant temperature is low, the motor 43 is activated by the temperature detection signal from the sensor 44 so that the flow rate adjusting plate 42 is displaced to the position indicated by the solid line where the passage T becomes wider. May be.

  Although not shown, the position control of the flow rate adjustment plate 42 shown in FIG. 8 is controlled by the motor 43 by a signal from a flow rate sensor that detects the flow rate of the coolant in the circulation pipe 12. Then, during high load operation of the fuel cell 11 with a high coolant flow rate, the motor 43 is activated by a detection signal from the flow sensor, and the flow rate adjusting plate 42 is displaced to a position where the passage T becomes narrow. On the contrary, the motor 43 may be activated by a detection signal from the flow sensor during low load operation with a low coolant flow rate, and the flow rate adjustment plate 42 may be displaced to a solid line position where the passage T becomes wider.

In place of the motor 43, an actuator such as an electromagnetic solenoid or a cylinder may be used.
In the embodiment, as shown in FIG. 3, the bypass pipe 17 and the ion exchanger 18 are connected to the circulation pipe 12 in parallel with the heat exchanger 14. Instead of this, a bypass pipe 17 and an ion exchanger 18 may be connected to the circulation pipe 12 in parallel with the pump 13.

  Also in this embodiment, when the fuel cell 11 is operated at a high load, the coolant is not excessively supplied to the ion exchanger 18 having a high pressure loss. Therefore, the coolant flowing through the circulation pipe 12 and the heat exchanger 14 is not used. The circulation flow rate of the fuel cell 11 is appropriately maintained without being reduced, and the fuel cell 11 can be properly cooled with the coolant.

  In the above embodiment, the present invention is embodied in a fuel cell system for an electric vehicle, but may be embodied in a cooling system for a fuel cell system for power generation in a production factory or a general household.

  E ... ion exchange resin, R ... resin storage chamber, 11 ... fuel cell, 12 ... circulation piping, 13 ... pump, 14 ... heat exchanger, 17 ... bypass piping, 18 ... ion exchanger, 21, 23 ... filter, 27 , 28, 31, 32, 42 ... flow rate adjusting plate, 44 ... sensor.

Claims (5)

A coolant circulation pipe is connected to the fuel cell, a pump for circulating the coolant is connected to the circulation pipe, and a heat exchanger for cooling the coolant in the circulation pipe is connected, and the bypass is bypassed to the circulation pipe. In a fuel cell cooling system in which a pipe is connected and an ion exchanger for adsorbing and removing impurity ions contained in the coolant in the circulation pipe is connected to the bypass pipe,
With respect to the flow direction of the cooling liquid in the container of the ion exchanger, an upstream filter and a downstream filter are accommodated at a predetermined interval, and a granular ion exchange resin is formed in a resin accommodation chamber formed between the two filters. The flow rate adjusting plate for adjusting the flow rate of the coolant flowing in the container is provided in the resin storage chamber, and the flow rate of the coolant flowing in the vessel is controlled by the flow rate adjusting plate during high load operation of the fuel cell. A fuel cell cooling system configured to reduce a flow rate. 2. The flow rate adjusting plate according to claim 1, wherein the flow rate adjusting plate is formed of an elastically deformable plate material, and when the flow rate of the cooling liquid increases, the flow rate adjusting plate is elastically deformed by the flow of the cooling liquid, and the passage sectional area of the cooling liquid is increased. A cooling system for a fuel cell, characterized by being configured to be reduced. 2. The flow rate adjusting plate according to claim 1, wherein when the temperature of the coolant in the container increases, the flow rate adjusting plate is deformed by the temperature and the passage cross-sectional area of the coolant is reduced. Fuel cell cooling system. 2. The fuel cell cooling system according to claim 1, wherein the flow rate adjusting plate is configured such that position switching control is performed by a signal from a sensor that detects the temperature of the coolant in the circulation pipe. . 2. The fuel cell cooling system according to claim 1, wherein the flow rate adjusting plate is configured to perform position switching control by a signal from a sensor that detects a flow rate of the coolant in the circulation pipe. .

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