KR102452542B1 - Heat exchange pipe and fuel cell system comprising the same - Google Patents

Abstract

The heat exchange pipe includes a first pipe and a first pipe providing a flow path through which the coolant flows between an inlet pipe provided at the front end and an outlet pipe provided at the rear end based on a flow direction in which the coolant flows to be supplied to the fuel cell stack. It is provided on the outside of the first tube along the longitudinal direction of the first tube and includes a PCM heat storage material filled in the hollow for heat exchange with the second tube and the cooling water forming a hollow between the first tube and the first tube and The second tube is formed to expand in a radial direction or contract in the opposite direction due to a change in internal pressure, and the heat exchange area between the coolant and the PCM heat storage material is increased by the expansion or contraction of the first tube and the second tube. As it fluctuates, the heat transfer rate between the coolant and the PCM heat storage material fluctuates.

Description

Heat exchange pipe and fuel cell system including same

The present invention relates to a heat exchange pipe and a fuel cell system including the same.

A fuel cell is a device that converts chemical energy stored in hydrocarbon or hydrogen fuel into electrical energy through an electrochemical reaction with air. Polymer Electrolyte Fuel Cell (PEFC) used in automobiles is a fuel cell that uses a polymer as an electrolyte and is operated at 100° C. or less. Hydrogen ions produced at the anode of the fuel cell stack move to the cathode through the electrolyte, and react with oxygen at the cathode to generate water and generate electricity.

However, the process of generating electricity in the fuel cell is an exothermic reaction, and the temperature inside the fuel cell stack may exceed 100°C depending on the operation of the fuel cell. Accordingly, it is necessary to supply cooling water to the inside of the fuel cell stack to maintain the temperature of the fuel cell stack at 100° C. or less.

In this case, in order to control the temperature of the cooling water, the cooling water supplied to the fuel cell stack may pass through a heat exchanger to release heat or receive heat, and a PCM heat storage material may be used for the heat exchanger. PCM is a material that changes phase according to temperature, and almost all substances in nature are PCM.

Because PCM absorbs or releases a large amount of thermal energy during phase change, it can be used to accumulate and release heat in fuel cell systems. That is, the PCM may be used as a heat storage material, and the heat stored in the PCM heat storage material may be supplied to the cooling water or the heat of the cooling water may be stored as the PCM heat storage material.

However, the temperature of the coolant supplied to the fuel cell stack during operation of the fuel cell system needs to be changed according to circumstances. However, in the conventional heat exchanger, since the heat transfer amount between the PCM heat storage material and the coolant cannot be changed, there is a problem in that the temperature of the coolant supplied to the fuel cell stack cannot be adjusted according to each situation.

An object of the present invention is to provide a heat exchange pipe capable of controlling the temperature of coolant supplied to a fuel cell stack.

In one example, the heat exchange pipe may include a first pipe providing a flow path through which the coolant flows between an inlet pipe provided at the front end and an outlet pipe provided at the rear end based on a flow direction in which the coolant to be supplied to the fuel cell stack flows. , A PCM heat storage material filled in the hollow is provided on the outside of the first tube, and in order to exchange heat with the second tube and the cooling water forming a hollow between the first tube and the first tube along the longitudinal direction of the first tube, The first tube and the second tube are formed to be expandable in a radial direction by a change in internal pressure or contractible in the opposite direction thereof, and between the cooling water and the PCM heat storage material by the expansion or contraction of the first tube and the second tube. The heat transfer rate between the coolant and the PCM heat storage material changes as the heat exchange area of

In another example, the first tube and the second tube may be formed to expand in a radial direction or contract in the opposite direction by a change in internal pressure according to an increase or decrease in the flow rate of the coolant.

In another example, in the heat exchange pipe, when the pressure inside the first tube and the second tube increases as the flow rate of the cooling water increases and the first tube and the second tube expand in the radial direction, the first tube is interposed therebetween. As the heat exchange area between the coolant and the PCM heat storage material increases, the heat transfer rate between the coolant and the PCM heat storage material may increase.

In another example, in the heat exchange pipe, when the pressure inside the first tube and the second tube decreases as the flow rate of the cooling water decreases and the first tube and the second tube contract in opposite directions, the first tube is interposed between the first tube and the second tube. The heat transfer area between the cooling water and the PCM heat storage material may decrease, so that the heat transfer rate between the cooling water and the PCM heat storage material may decrease.

In another example, the first tube and the second tube expand radially as the pressure therein increases, reaching an expansion limit at which further expansion is inhibited.

In another example, the heat exchange pipe is provided to be spaced apart from the outside of the second pipe by a predetermined distance to surround the second pipe, and further includes an outer case that is not deformed by pressure according to the expansion of the second pipe, the first pipe and When the second tube expands so that the second tube comes into contact with the outer case, the outer case may prevent the second tube from expanding and reach the expansion limit.

In another example, a through hole communicating with the outside is formed in the outer case, and air between the outer case and the second tube may move to the outside through the through hole according to the expansion of the first tube and the second tube.

In another example, the PCM heat storage material is filled in a hollow state accommodated in a plurality of microcapsules, and the plurality of microcapsules may have fluidity inside the hollow even when the PCM heat storage material is phase-changed to a solid state.

In another example, the heat exchange pipe may further include a lubricant provided in the hollow and interposed between the microcapsules in order to prevent the microcapsules from being damaged due to friction between the microcapsules.

In another example, in the fuel cell system, a fuel cell stack including an anode and an air electrode, a heat exchange pipe through which coolant supplied to the fuel cell stack exchanges heat, and a heat exchange pipe provided at a front end of the heat exchange pipe based on a flow direction in which the coolant flows to heat exchange an inlet pipe for introducing cooling water into the pipe and an outlet pipe provided at the rear end of the heat exchange pipe based on the flow direction to discharge the cooling water from the heat exchange pipe, wherein the heat exchange pipe provides a flow path through which the cooling water flows between the inlet pipe and the outlet pipe a first pipe, which is provided on the outside of the first pipe, and includes a PCM heat storage material filled in the hollow to exchange heat with a second pipe and cooling water that forms a hollow between the first pipe and the first pipe or The first tube and the second tube are formed to be expandable in a radial direction or contractible in an opposite direction thereof by a pressure change therein.

In another example, in the fuel cell system, as the heat exchange area between the coolant and the PCM heat storage material is changed due to expansion or contraction of the first tube and the second tube, the heat transfer rate between the coolant and the PCM heat storage material may be changed.

In another example, the first tube and the second tube may be formed to expand in a radial direction or contract in the opposite direction by a change in internal pressure according to an increase or decrease in the flow rate of the coolant.

In another example, the fuel cell system is provided in the interior of the discharge pipe close to the first pipe, and prevents the cooling water from flowing into the discharge pipe, thereby increasing the internal pressure of the first pipe according to an increase in the flow rate of the cooling water. It may include more wealth.

In another example, the pressing part may be formed in a shape that gradually decreases the internal cross-sectional area of the discharge pipe along the flow direction.

In another example, the fuel cell system further includes a control unit for controlling the flow rate of the cooling water, wherein the control unit increases the flow rate of the cooling water to increase the heat transfer rate and decreases the heat transfer rate, It is possible to reduce the flow rate of the coolant.

In another example, the first tube and the second tube expand radially as the pressure therein increases, reaching an expansion limit at which further expansion is required to be inhibited.

In another example, the fuel cell system further includes a pump for pumping cooling water to the heat exchange pipe, and a pressure sensor for measuring a pressure of the cooling water flowing in the first tube, wherein the controller is configured to determine whether the pressure of the cooling water is limited to the expansion limit. The pump can be controlled so that it is below the limit pressure, which is the pressure when it is reached.

In another example, the fuel cell system further includes a pump for pumping cooling water to the heat exchange pipe, and the controller is configured to operate at a maximum RPM of the pump below a limit RPM that is an operating RPM of the pump when the expansion limit is reached. You can control the pump.

In another example, the fuel cell system further includes a pressurizing unit provided inside the discharge pipe to increase the internal pressure of the first pipe by preventing the coolant from flowing into the discharge pipe, wherein the pressurizing unit is perpendicular to the longitudinal direction of the discharge pipe a flat plate for closing the discharge tube in a first position or opening the discharge tube at a second position parallel to the longitudinal direction of the discharge tube, the flat plate rotating between the first position and the second position, the first tube and The second tube may be formed to expand in a radial direction or contract in the opposite direction by a change in internal pressure according to the degree of rotation of the plate.

In another example, the fuel cell system further includes a pair of closing members respectively connected to both ends of the first pipe and the second pipe, and the ends of the inlet pipe and the outlet pipe are inserted into the first pipe, The closing member is formed with an insertion hole into which the inlet pipe or the outlet pipe is sealedly inserted, and slides along the outer surface of the inlet pipe or the outlet pipe by the expansion or contraction of the first and second pipes, and also the first pipe and the second pipe The hollow can be sealed from the outside through the connection with the tube.

In another example, in a fuel cell system, the first tube and the second tube expand radially as the pressure therein increases. When an expansion limit at which further expansion is required is reached, the closing member is In order to prevent further movement toward the center of the first tube, it may further include a stopper provided to protrude from the surface of the inlet pipe or the outlet pipe.

In another example, the fuel cell system may further include a reinforcing member surrounding outer surfaces of the first tube and the second tube to improve the rigidity of the first tube and the second tube.

According to the present invention, since the amount of heat transfer between the PCM heat storage material and the coolant can be adjusted by adjusting the pressure inside the first pipe through which the coolant flows, the temperature of the coolant supplied to the fuel cell stack can be controlled.

1 is a configuration diagram illustrating a fuel cell system according to embodiments of the present invention.
2 is a view showing a cross section of a heat exchange pipe according to Embodiment 1 of the present invention cut in a direction perpendicular to the longitudinal direction.
3 is a view showing a cross section of the heat exchange pipe according to the first embodiment of the present invention cut in a direction perpendicular to the longitudinal direction.
4 is a view showing a cross-section of the heat exchange pipe according to the first embodiment of the present invention cut in the longitudinal direction.
5 is a view showing a cross-section of the heat exchange pipe according to the first embodiment of the present invention cut in the longitudinal direction.
6 is a view showing a cross section of a heat exchange pipe according to a second embodiment of the present invention cut in a direction perpendicular to the longitudinal direction.
7 is a view showing a cross-section of a heat exchange pipe according to a second embodiment of the present invention cut in the longitudinal direction.
8 is a view showing a cross-section of a heat exchange pipe according to a second embodiment of the present invention cut in the longitudinal direction;

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in the description of the embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

Example One

1 is a configuration diagram illustrating a fuel cell system according to embodiments of the present invention. 2 and 3 are views showing a cross-section taken in a direction perpendicular to the longitudinal direction of the heat exchange pipe according to the first embodiment of the present invention. 4 and 5 are views showing cross-sections cut in the longitudinal direction of the heat exchange pipe according to Embodiment 1 of the present invention. Hereinafter, a fuel cell system according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 5 .

The fuel cell system according to Embodiment 1 of the present invention includes a fuel cell stack 1 , a heat exchange pipe 2 , an inlet pipe 3 , and an exhaust pipe 4 .

The fuel cell stack 1 includes a fuel electrode (not shown) and an air electrode (not shown). The fuel cell stack 1 may generate electricity by reacting hydrogen fuel supplied to the anode and oxygen supplied to the cathode. When electricity is generated in the fuel cell stack 1 , heat is generated, and in order to maintain the temperature of the fuel cell stack 1 at 100° C. or less, cooling water may be supplied to the fuel cell stack 1 .

The heat exchange pipe 2 flows the coolant supplied to the fuel cell stack 1 . Cooling water supplied to the fuel cell stack 1 is heat-exchanged inside the heat exchange pipe 2 and supplied to the fuel cell stack 1 .

The inlet pipe 3 is provided at the front end of the heat exchange pipe 2 based on the flow direction in which the coolant flows. The inlet pipe 3 introduces cooling water into the heat exchange pipe 2 .

The discharge pipe 4 is provided at the rear end of the heat exchange pipe 2 based on the flow direction in which the coolant flows. The cooling water flowing through the heat exchange pipe 2 is discharged from the discharge pipe 4 .

Cooling water flows into the heat exchange pipe 2 through the inlet pipe 3, receives heat from the heat exchange pipe 2 or releases heat, and then is discharged through the discharge pipe 4 to be supplied to the fuel cell stack 1. can

Hereinafter, the heat exchange pipe 2 will be described in more detail with reference to FIGS. 2 to 5 .

The heat exchange pipe 2 includes a first pipe 10 , a second pipe 20 , and a PCM heat storage material 30 .

The first pipe 10 provides a flow path through which the cooling water flows between the inlet pipe 3 and the outlet pipe 4 . The coolant introduced through the inlet pipe 3 may flow through the inside of the first pipe 10 and then be discharged to the discharge pipe 4 .

The second tube 20 is provided outside the first tube 10 . The second pipe 20 forms a hollow 15 between the first pipe 10 and the first pipe 10 along the longitudinal direction of the first pipe 10 .

The PCM heat storage material 30 is filled in the hollow 15 formed between the first tube 10 and the second tube 20 . Cooling water flows inside the first tube 10 , and the PCM heat storage material 30 is filled in the hollow 15 between the first tube 10 and the second tube 20 . The PCM heat storage material 30 exchanges heat with the cooling water. That is, the coolant may be supplied to the fuel cell stack 1 after heat exchange with the PCM heat storage material 30 while flowing in the first tube 10 .

At this time, the first tube 10 and the second tube 20 are formed to expand in a radial direction by a change in internal pressure or to be contractible in the opposite direction thereof. When the internal pressure increases and the first tube 10 expands in the radial direction, the PCM heat storage material 30 filled in the hollow 15 also receives pressure in the radial direction. When the PCM heat storage material 30 receives enough pressure to press the second tube 20 , the second tube 20 may also expand in the radial direction.

That is, when the internal pressure increases, only the first tube 10 may radially expand, or both the first tube 10 and the second tube 20 may radially expand. And when the internal pressure is reduced, the expanded first pipe or the first pipe 10 and the second pipe 20 may be contracted in the opposite direction to the radial direction.

At this time, the PCM heat storage material 30 needs to have fluidity according to the expansion or contraction of the first tube 10 and the second tube 20 . However, in general, when the PCM heat storage material 30 is solidified in a solid state, it becomes hard and cannot flow in the hollow 15 .

The PCM heat storage material 30 according to the first embodiment of the present invention may be filled in the hollow 15 in a state accommodated in a plurality of microcapsules to have fluidity. Since the PCM heat storage material 30 will undergo a phase change inside the microcapsule, a plurality of microcapsules having a size of several micrometers to several hundred micrometers are formed in the hollow 15 even when the PCM heat storage material 30 is phase-changed to a solid state. may have liquidity.

And since the microcapsules may be damaged according to friction generated when the microcapsules flow, the heat exchange pipe 2 may further include a lubricant provided in the hollow 15 and interposed between the microcapsules.

When the first tube 10 and the second tube 20 expand or contract, the heat exchange area between the cooling water and the PCM heat storage material 30 is changed. And, as the heat exchange area between the coolant and the PCM heat storage material 30 varies, the heat transfer rate between the coolant and the PCM heat storage material 30 varies.

More specifically, when the first tube 10 and the second tube 20 expand and the heat exchange area between the coolant and the PCM heat storage material 30 increases, the heat transfer rate may increase, and the first tube 10 and the second tube When 20 contracts and the heat exchange area between the coolant and the PCM heat storage material 30 decreases, the heat transfer rate may decrease.

That is, the heat transfer rate between the PCM heat storage material 30 and the coolant may be adjusted by adjusting the internal pressure, and the temperature of the coolant supplied to the fuel cell stack 1 may also be adjusted. Accordingly, the temperature of the coolant supplied to the fuel cell stack 1 may be adjusted while using the same PCM heat storage material 30 .

The fuel cell system according to Embodiment 1 of the present invention may further include a pressurizing part 40 for increasing the pressure inside the first tube 10 . The pressurizing part 40 is provided in the interior of the discharge pipe 4 to be adjacent to the first pipe 10 , and may prevent the cooling water from flowing into the discharge pipe 4 .

The pressing part 40 may be formed in a shape that gradually decreases the internal cross-sectional area of the discharge pipe 4 along the flow direction. For example, the orifice 41 may be provided in the discharge pipe (4).

The internal pressure of the first pipe 10 and the second pipe 20 may be changed according to an increase or decrease in the flow rate of the cooling water. When the flow rate of the cooling water is increased, the cooling water that has not been discharged to the discharge pipe 4 by the pressurizing unit 40 may pressurize the first pipe 10 and the second pipe. As a result, the pressure inside the first tube 10 and the second tube 20 may increase. Conversely, when the flow rate of the coolant decreases, the internal pressure of the first tube 10 and the second tube 20 may decrease.

More specifically, when the internal pressure of the first pipe 10 and the second pipe 20 is increased by increasing the flow rate of the cooling water in a state in which it is not expanded or contracted, the first pipe 10 and the second pipe 20 are not expanded or contracted. 20 expands, and the heat transfer area between the cooling water and the PCM heat storage material 30 increases, so that the heat transfer rate may increase.

And when the flow rate of the cooling water is reduced again and the internal pressure is below a certain pressure, the first pipe 10 and the second pipe 20 contract again, and the heat exchange area between the cooling water and the PCM heat storage material 30 is reduced. The heat transfer rate may decrease.

However, the first tube 10 and the second tube 20 expand radially as the internal pressure increases, and further expansion is inhibited, or the expansion limit at which further expansion is inhibited is reached. can If the expansion limit is not set, the rigidity of the first pipe 10 or the second pipe 20 cannot overcome the pressure caused by the expansion, and the first pipe 10 or the second pipe 20 may be damaged. Therefore, it is necessary to prevent further expansion when the expansion limit is reached.

For example, the heat exchange pipe 2 according to Embodiment 1 of the present invention further includes an outer case 50 , and the outer case 50 controls the expansion of the first tube 10 and the second tube 20 . can stop

The outer case 50 is provided to be spaced apart from the outside of the second tube 20 by a predetermined distance and surrounds the second tube 20 , and is not deformed by the pressure according to the expansion of the second tube 20 , so that the first tube 10 is not deformed. ) and the expansion of the second tube 20 can be prevented.

The first tube 10 and the second tube 20 expand in the radial direction as the internal pressure increases. When the outer case 50 comes into contact, the outer case 50 blocks the expansion of the second tube 20 . And, the first tube 10 and the second tube 20 may reach the expansion limit.

And a through hole 55 communicating with the outside may be formed in the outer case 50 , and the air between the outer case 50 and the second tube 20 is the first tube 10 and the second tube 20 . It may move to the outside through the through hole 55 according to the expansion. The through hole 55 is formed so that the air between the outer case 50 and the second tube 20 according to the expansion of the second tube 20 can remove the pressure that presses the outer case 50 .

Through this configuration, only by changing the flow rate of the coolant, the heat transfer rate between the coolant and the PCM heat storage material 30 may be adjusted, and accordingly, the temperature of the coolant supplied to the fuel cell stack 1 may be adjusted.

Example 2

6 is a view showing a cross-section of a heat exchange pipe according to a second embodiment of the present invention cut in a direction perpendicular to the longitudinal direction. 7 and 8 are views showing cross-sections of a heat exchange pipe according to a second embodiment of the present invention cut in the longitudinal direction. Hereinafter, a fuel cell system according to a second embodiment of the present invention will be described with reference to FIGS. 6 to 8 .

The fuel cell system according to the second embodiment is different from the fuel cell system according to the first embodiment in the presence or absence of the outer case 50 , the shape of the heat exchange pipe 2 ′, and the shape of the pressurizing part 40 ′.

First, in the fuel cell system according to Embodiment 2 of the present invention, the ends of the inlet pipe 3 and the outlet pipe 4 may be inserted into the first pipe 10 . 7 and 8 , the first tube 10 may have a shape surrounding the ends of the inlet tube 3 and the outlet tube 4 .

And, it may further include a pair of closing members 60 respectively connected to both ends of the first tube 10 and the second tube 20. In this case, the outer case 50 may not be provided.

The closing member 60 may have an insertion hole (not shown) into which the inlet pipe 3 or the outlet pipe 4 is sealedly inserted. It is inserted into the inlet pipe 3 or the discharge pipe 4 through the insertion hole, and the inner surface of the insertion hole and the outer surface of the inlet pipe 3 or the inner surface of the insertion hole and the inner surface of the discharge pipe 4 may be sealed.

In addition, it is possible to seal the hollow 15 between the first tube 10 and the second tube 20 from the outside through the connection with the first tube 10 and the second tube 20, and the first tube The space between the (10) and the inlet pipe (3) or the first pipe (10) and the discharge pipe (4) can also be sealed from the outside.

The closing member 60 may slide along the outer surface of the inlet pipe 3 or the outlet pipe 4 according to the expansion or contraction of the first pipe 10 and the second pipe 20 . There is no particular limitation on the sliding method.

In addition, the outer surfaces of the first tube 10 and the second tube 20 may be surrounded by reinforcing members 14 and 24 for improving the rigidity of the first tube 10 and the second tube 20 . For example, a reinforcing material in the form of a mesh may surround the first tube 10 and the second tube 20 . The reinforcing members 14 and 24 allow the first tube 10 and the second tube 20 to expand more in the radial direction than without the reinforcing members 14 and 24 . Since the total volume of the hollow 15 is constant as the first tube 10 and the second tube 20 expand in the radial direction, the ends of the first tube 10 and the second tube 20 are It may be moved toward the center of the tube 10 and the second tube 20 .

The fuel cell system according to Embodiment 2 of the present invention may further include a stopper 70 . The stopper 70 may prevent the first tube 10 from moving further toward the center of the first tube 10 while sliding.

More specifically, when the first tube 10 and the second tube 20 expand radially as the internal pressure increases, and reaches the expansion limit required to prevent further expansion, the closing member 60 is Movement may be prevented by the stopper 70 (see FIG. 8 ).

That is, the formation position of the stopper 70 can control the expansion limit. The stopper may be provided to protrude from the surface of the inlet pipe or the outlet pipe. For example, the stopper 70 may be formed in a ring shape surrounding the outer surface of the inlet pipe 3 or the outlet pipe 4 and coupled to the outer surface of the inlet pipe 3 or the outlet pipe 4 to be fixed.

Next, the pressing part 40' according to the second embodiment of the present invention closes the discharge pipe 4 at a first position perpendicular to the longitudinal direction of the discharge pipe 4, or parallel to the longitudinal direction of the discharge pipe 4 It may include a plate 43 that opens the discharge pipe 4 in a second position.

And the flat plate 43 may rotate between the first position and the second position. For example, as shown in FIGS. 7 and 8 , it may be coupled to the rotation shaft 45 provided in the interior of the discharge pipe 4 and rotated between the first position and the second position.

The first tube 10 and the second tube 20 may be formed to expand in a radial direction or contract in the opposite direction according to the degree of rotation of the flat plate 43 . More specifically, when the flat plate 43 is in the first position, the internal cross-sectional area of the discharge pipe 4 is narrow, and the flow of the cooling water to the discharge pipe 4 may be prevented. Accordingly, the coolant that has not been discharged to the discharge pipe 4 will pressurize the first pipe 10 and the second pipe 20 , and accordingly, the first pipe 10 and the second pipe 20 may expand.

However, when the flat plate 43 is in the second position, the cross-sectional area of the inside of the discharge pipe 4 will be widened, and the flow of the cooling water to the discharge pipe 4 is not greatly hindered, so that the first pipe 10 and the second pipe ( 20) the amount of cooling water pressurizing will be less. Accordingly, the first tube 10 and the second tube 20 may contract in opposite directions.

As such, by including the rotatable flat plate 43 at the first and second positions, the expansion or contraction of the first tube 10 and the second tube 20 can be adjusted even without adjusting the flow rate of the cooling water. The fuel cell system according to the second embodiment of the present invention may further include a control unit (not shown) for controlling the pressing unit 40', and the PCM heat storage material ( 30) and the coolant, the temperature of the coolant supplied to the fuel cell stack 1 may be adjusted.

Example 3

The fuel cell system according to the third embodiment of the present invention is different from the fuel cell system according to the first embodiment in the configuration of allowing the first tube 10 and the second tube 20 to reach the expansion limit.

The fuel cell system according to Embodiment 3 of the present invention may further include a pump 5 , a pressure sensor (not shown), and a controller (not shown).

The pump 5 may pressurize the cooling water to the heat exchange pipe 2 . The pressure sensor may measure the pressure of the coolant flowing in the first tube 10 .

The control unit may control the operation of the pump 5 . The controller may control the pump 5 to control the flow rate of the cooling water. To increase the heat transfer rate, the flow rate of the cooling water may be increased, and to decrease the heat transfer rate, the flow rate of the cooling water may be decreased.

In addition, the pump 5 may be controlled so that the pressure of the coolant measured by the pressure sensor is equal to or less than the limit pressure. The limit pressure refers to a pressure when the pressure of the cooling water flowing inside the first pipe 10 becomes the pressure when the first pipe 10 and the second pipe 20 reach the expansion limit. The control unit controls the pump 5 so that the pressure of the pump 5 is equal to or less than the limit pressure, so that the first tube 10 and the second tube 20 do not reach the expansion limit or, even if they reach the limit, no longer reach the expansion limit. Expansion may be controlled to be inhibited.

At this time, the reference of the limit pressure is not necessarily the pressure of the coolant, and may be the pressure inside the first pipe 10 or the pressure in the hollow 15 between the first pipe and the second pipe 20 .

Alternatively, the control unit may control the pump 5 so that the operating RPM of the pump 5 operates below the limit RPM, thereby preventing the first tube 10 and the second tube 20 from expanding more than the expansion limit. . Here, the limit RPM refers to the operating RPM of the pump 5 when the first tube 10 and the second tube 20 reach the expansion limit.

The control unit controls the pump 5 so that the maximum RPM of the pump 5 operates below the limit RPM so that the first tube 10 and the second tube 20 do not reach the expansion limit, or even reach the expansion limit. It can be controlled so that abnormal expansion is prevented. When the maximum RPM of the pump 5 is controlled to operate below the limit RPM, there is no need to monitor the pressure of the coolant and there is no need for a pressure sensor, so the control can be much simpler.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

1: fuel cell stack
2, 2': heat exchange pipe
3: Inlet pipe
4: discharge pipe
5: Pump
10: Section 1
14: reinforcing member
15: hollow
20: tube 2
24: reinforcing member
30: PCM heat storage material
40, 40': pressing part
41: orifice
43: Reputation
45: axis of rotation
50: outer case
55: through hole
60: finishing member

Claims (22)

a first pipe providing a flow path through which the coolant flows between an inlet pipe provided at the front end and an outlet pipe provided at the rear end based on a flow direction in which the coolant to be supplied to the fuel cell stack flows;
a second pipe provided on the outside of the first pipe and forming a hollow between the first pipe and the first pipe along the longitudinal direction of the first pipe; and
In order to exchange heat with the cooling water, it comprises a PCM heat storage material filled in the hollow,
The first tube and the second tube are formed to expand in a radial direction by a change in internal pressure or to be contractible in the opposite direction thereof,
A heat exchange pipe in which a heat transfer rate between the cooling water and the PCM heat storage material is changed as a heat exchange area between the cooling water and the PCM heat storage material is changed due to expansion or contraction of the first tube and the second tube. The method according to claim 1,
The first pipe and the second pipe are formed to be expandable in the radial direction or contractible in the opposite direction by a change in internal pressure according to an increase or decrease in the flow rate of the cooling water. 3. The method according to claim 2,
When the pressure inside the first tube and the second tube increases as the flow rate of the coolant increases and the first tube and the second tube expand in the radial direction, the first tube and the second tube are interposed therebetween. A heat exchange pipe, wherein a heat exchange area between the coolant and the PCM heat storage material increases to increase a heat transfer rate between the coolant and the PCM heat storage material. 3. The method according to claim 2,
When the pressure inside the first tube and the second tube decreases according to the decrease in the flow rate of the cooling water, and the first tube and the second tube contract in the opposite directions, the first tube and the second tube are interposed therebetween. A heat exchange pipe, wherein a heat exchange area between the coolant and the PCM heat storage material is reduced, so that a heat transfer rate between the coolant and the PCM heat storage material is reduced. The method according to claim 1,
wherein the first tube and the second tube expand radially as the internal pressure increases, reaching an expansion limit at which further expansion is prevented. 6. The method of claim 5,
It is provided to be spaced apart from the outside of the second tube by a predetermined distance and surrounds the second tube, further comprising an outer case that is not deformed by the pressure according to the expansion of the second tube,
When the first tube and the second tube expand so that the second tube contacts the outer case, the outer case prevents the second tube from expanding to reach the expansion limit. 7. The method of claim 6,
A through hole communicating with the outside is formed in the outer case,
The air between the outer case and the second tube, according to the expansion of the first tube and the second tube, moves to the outside through the through hole, a heat exchange pipe. The method according to claim 1,
The PCM heat storage material is filled in the hollow in a state accommodated in a plurality of microcapsules,
The plurality of microcapsules have fluidity inside the hollow even when the PCM heat storage material is phase-changed to a solid state, the heat exchange pipe. 9. The method of claim 8,
In order to prevent the microcapsules from being damaged by friction between the microcapsules, the heat exchange pipe further includes a lubricant provided in the hollow and interposed between the microcapsules. a fuel cell stack including an anode and a cathode;
a heat exchange pipe through which the coolant supplied to the fuel cell stack exchanges heat;
an inlet pipe provided at a front end of the heat exchange pipe based on a flow direction in which the coolant flows and for introducing the coolant into the heat exchange pipe; and
and a discharge pipe provided at the rear end of the heat exchange pipe based on the flow direction to discharge the cooling water from the heat exchange pipe,
The heat exchange pipe may include a first pipe providing a flow path through which the cooling water flows between the inlet pipe and the outlet pipe, a second pipe provided outside the first pipe, and forming a hollow between the first pipe and the first pipe In order to exchange heat with the tube and the cooling water, it comprises a PCM heat storage material filled in the hollow,
The first tube or the first tube and the second tube are formed to be expandable in a radial direction by a change in internal pressure or contractible in the opposite direction thereof. 11. The method of claim 10,
The heat transfer rate between the coolant and the PCM heat storage material is changed as a heat exchange area between the coolant and the PCM heat storage material is changed due to expansion or contraction of the first tube and the second tube. 12. The method of claim 11,
The first pipe and the second pipe are formed to be expandable in the radial direction or contractible in the opposite direction by a change in internal pressure according to an increase or decrease in the flow rate of the coolant. 13. The method of claim 12,
It is provided in the interior of the discharge pipe close to the first pipe, and prevents the cooling water from flowing into the discharge pipe, further comprising a pressurizing part that increases the internal pressure of the first pipe according to an increase in the flow rate of the cooling water , fuel cell systems. 14. The method of claim 13,
The pressurizing portion is formed in a shape to gradually decrease the internal cross-sectional area of the discharge pipe along the flow direction, the fuel cell system. 13. The method of claim 12,
Further comprising a control unit for controlling the flow rate of the cooling water,
The control unit increases the flow rate of the cooling water when increasing the heat transfer rate and decreases the flow rate of the coolant when decreasing the heat transfer rate. 16. The method of claim 15,
The first tube and the second tube expand radially as the internal pressure increases, reaching an expansion limit at which further expansion is inhibited. 17. The method of claim 16,
a pump for pressurizing the cooling water to the heat exchange pipe; and a pressure sensor for measuring the pressure of the cooling water flowing in the first pipe;
wherein the control unit controls the pump so that the pressure of the coolant becomes equal to or less than a limit pressure, which is a pressure when the pressure of the coolant reaches the expansion limit. 17. The method of claim 16,
Further comprising a pump for pressurizing the cooling water to the heat exchange pipe,
The control unit controls the pump so that the maximum RPM of the pump operates below a limit RPM that is an operating RPM of the pump when the expansion limit is reached. 12. The method of claim 11,
It is provided inside the discharge pipe, further comprising a pressurizing part for increasing the internal pressure of the first pipe by preventing the cooling water from flowing to the discharge pipe,
The pressing unit includes a flat plate that closes the discharge pipe at a first position perpendicular to the longitudinal direction of the discharge pipe, or opens the discharge pipe at a second position parallel to the longitudinal direction of the discharge pipe,
The flat plate rotates between the first position and the second position,
The first tube and the second tube are formed to be expandable in the radial direction or contractible in the opposite direction by a change in internal pressure according to the degree of rotation of the flat plate. 12. The method of claim 11,
Further comprising a pair of closing members respectively connected to both ends of the first tube and the second tube,
Ends of the inlet pipe and the outlet pipe are inserted into the first pipe,
The closing member is formed with an insertion hole into which the inlet pipe or the outlet pipe is sealedly inserted, and slides along the outer surface of the inlet pipe or the outlet pipe by expansion or contraction of the first and second pipes, and A fuel cell system that seals the hollow from the outside through a connection with the first pipe and the second pipe. 21. The method of claim 20,
The first tube and the second tube expand radially as the internal pressure increases. When the expansion limit at which further expansion is inhibited is reached, the closing member moves toward the center of the first tube. In order to prevent further movement, the fuel cell system further comprises a stopper provided to protrude from the surface of the inlet pipe or the discharge pipe. 22. The method of claim 21,
In order to improve the rigidity of the first tube and the second tube, the fuel cell system further comprising a reinforcing member surrounding outer surfaces of the first tube and the second tube.

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