KR100551289B1 - A heat control system of fuel cell - Google Patents

Abstract

Parallel to the method for sending the coolant to the water storage tank using a water pump so that a small amount of coolant remaining in the pipe can be stored by gravity in a separate auxiliary water storage tank;

An upper water storage tank including a heating unit, a fuel cell stack, and a heat exchanger are connected to each other through a pipe, and a water pump is formed on a first pipe connecting the fuel cell stack and the heat exchanger to stack the fuel cell in the stack case. In the heat management system for a fuel cell consisting of a cooling circuit for cooling the heat by a heat exchange method, the branch inlet pipe and the branch which is located at the lowermost with respect to the gravity direction of the cooling circuit branched from the first pipe connecting the fuel cell stack and the heat exchanger Auxiliary water storage tank to which the outlet pipe is connected; A first shut-off valve mounted on a second pipe connecting the heat exchanger and the upper water storage tank to open and close the second pipe according to a control signal of a controller; A second shut-off valve mounted on a third pipe connecting the upper water storage tank and the fuel cell stack to open and close the third pipe according to a control signal of a controller; A third shut-off valve mounted on a branch air engine configured to branch from one side of the third pipe to suck external air, and configured to open and close the branch air engine according to a control signal of a controller; A fourth shut-off valve mounted on the branch inlet pipe branched from one side of the first pipe and connected to the auxiliary water storage tank to open and close the branch inlet pipe according to a control signal of a controller; A fifth shut-off valve mounted on the branch outlet pipe branched from the other side of the first pipe and connected to the auxiliary water storage tank, for opening and closing the branch outlet pipe according to a control signal of a controller; A first water level sensor installed in the upper water storage tank to detect a water level inside the tank and output a signal to the controller; And a second water level sensor installed on one side between the water pump and the fuel cell stack on the first pipe to sense a water level inside the first pipe and output a signal to the controller. Provide a system.

Fuel Cells, Stacks, Thermal Management Systems

Description

Thermal Management System for Fuel Cells {A HEAT CONTROL SYSTEM OF FUEL CELL}

1 and 2 is a block diagram of a thermal management system for a fuel cell according to the prior art,

3 is a block diagram of a thermal management system for a fuel cell according to an exemplary embodiment of the present invention.

The present invention relates to a thermal management system for a fuel cell, and more particularly, a method for sending cooling water to a water storage tank using an existing water pump and an auxiliary water storage tank for storing a small amount of water remaining in a pipe. The present invention relates to a thermal management system for a fuel cell that enables effective thermal management of the fuel cell.

In recent years, global environmental issues have become an important concern around the world, and various regulations have been enacted internationally to protect the environment. The most important environmental pollution is mainly caused by the use of petroleum fuel, which is increasing every year, it is very important to reduce the pollution caused by the vehicle.

In order to cope with this, electric vehicles, hybrid vehicles of internal batteries and internal combustion engines, fuel cell vehicles, etc. are being developed to reduce pollution caused by the development of low-pollution vehicles. There is a limit to. A promising technology that can solve the problems of the internal combustion engine and the electric vehicle is an electric vehicle using a fuel cell.

The fuel cell has a high power generation efficiency as compared with the conventional power generation method, and there is no emission of pollutants due to power generation, so it is evaluated as a future power generation technology, and various fuels can be used to be developed as future electricity.

In other words, fuel cells generate electricity and heat by reaction of hydrogen and oxygen, and sulfonic acid is a representative polymer used as a hydrogen ion electrolyte membrane in proton exchange membrane fuel cells (PEMFC). Nafion containing a salt (sulfonate; -SO ₃ H) group is applied, the movement of hydrogen ions in the Nafion is moved with water by a sulfonate group (sulfonate).

In order to show the hydrogen ion conductivity at Nafion, a certain amount of water must be present in the membrane, and the fuel must be humidified to prevent evaporation of water in the membrane by dry fuel (air or hydrogen). do.

At this time, the humidification of the fuel uses an external humidification by a method such as a humidifier and a method of self-humidification in the fuel cell stack.

As the fluid used to humidify the fuel, de-ionized water must be used. In the case of self-humidification, distilled water is used as humidifying water to humidify the fuel, and also as cooling water for cooling the stack. do.

In the case of external humidification, distilled water may be used as humidification water, but distilled water or antifreeze may be used as stack cooling water.

In the above, in the case of self-humidification, since distilled water is used as the humidifying water or the cooling water, the external environment is greatly affected. In other words, when the external temperature is below zero (0 ° C or less), the distilled water in the system has a problem of freezing.

When the distilled water freezes below zero, the distilled water, which is the coolant, does not flow in the fuel cell thermal management system, so that the fuel supplied to the fuel cell stack cannot be humidified and the heat generated by the fuel cell cannot be cooled. . Also, if frozen in the pipe or parts, there is a risk of breaking the pipe or parts.

To compensate for this, when the system stops operating, the distilled water remaining in the pipe or parts must be removed.The distilled water is removed from the fuel cell thermal management system and stored in a separate water storage tank. Distilled water is melted through a heater or heat exchanger.

Therefore, when the fuel cell system is stopped, in order to collect distilled water in a separate water storage tank, gravity drain is used as shown in FIG. 1, or a water pump is used as in FIG. 2.

First, when the distilled water is collected using gravity, the positional correlation of the components in the fuel cell thermal management system 101 becomes very important. That is, even if gravity is used in the system and the water is forcibly drained to remove the water, the water storage tank 103 should be located at the lowest position among the system parts.

In addition, when distilled water is collected in the water storage tank 205 using a separate recovery water pump 203, water is additionally added to the water pump 207 for driving the cooling water on the piping in the fuel cell thermal management system 201. The recovered water pump 203 is used to send distilled water in the pipe to the water storage tank 205 to collect the distilled water. At startup, the distilled water in the water storage tank 205 is melted using a heater or a heat exchanger. After that, it can be used as humidifying or cooling water.

In this case, although there is a degree of freedom in the position of the water storage tank 205, an additional recovery water pump 203 for recovering water must be mounted. In addition, since all the water in the pipe cannot be removed by the recovery water pump 203, the water remaining in the fuel cell thermal management system 201, such as the water pump 207, may freeze, which may damage parts or hinder the flow of cooling water. There is a problem.

Accordingly, the present invention has been invented to solve the above problems, the object of which is to separate the small amount of cooling water remaining in the pipe by gravity in parallel with the method for sending the cooling water to the water storage tank using a water pump. It is to provide a thermal management system for a fuel cell that can be stored in an auxiliary water storage tank.

The present invention for realizing the above object is connected to the upper water storage tank including the heating unit and the fuel cell stack and the heat exchanger through a mutual pipe, the water pump on the first pipe connecting the fuel cell stack and the heat exchanger In the thermal management system for a fuel cell consisting of a cooling circuit configured to cool the fuel cell stack by heat exchange in the stack case,

An auxiliary water storage tank positioned at a lower portion with respect to the gravity direction of the cooling circuit and branched from a first pipe connecting the fuel cell stack and the heat exchanger to a branch inlet pipe and a branch outlet pipe; A first shut-off valve mounted on a second pipe connecting the heat exchanger and the upper water storage tank to open and close the second pipe according to a control signal of a controller; A second shut-off valve mounted on a third pipe connecting the upper water storage tank and the fuel cell stack to open and close the third pipe according to a control signal of a controller; A third shut-off valve mounted on a branch air engine configured to branch from one side of the third pipe to suck external air, and configured to open and close the branch air engine according to a control signal of a controller; A fourth shut-off valve mounted on the branch inlet pipe branched from one side of the first pipe and connected to the auxiliary water storage tank to open and close the branch inlet pipe according to a control signal of a controller; A fifth shut-off valve mounted on the branch outlet pipe connected to the auxiliary water storage tank branched from the other side of the first pipe and opening and closing the branch outlet pipe according to a control signal of a controller; A first water level sensor installed in the upper water storage tank to detect a water level inside the tank and output a signal to the controller; And a second water level sensor installed on one side between the water pump and the fuel cell stack on the first pipe to sense the water level inside the first pipe and output the signal to the controller.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a configuration diagram of a fuel cell thermal management system according to an embodiment of the present invention, the configuration of the fuel cell thermal management system 1 according to an embodiment of the present invention is the fuel cell stack 3 and the heat exchanger (5) and heating The upper water storage tank 7 for storing the distilled water circulating the pipe including the unit (HU) is connected to each other through the first pipe (L1), the second pipe (L2) and the third pipe (L3), A cooling circuit configured to form a water pump 9 on the first pipe L1 connecting the fuel cell stack 3 and the heat exchanger 5 to cool the fuel cell stack 3 inside the stack case by heat exchange. It consists of.

In addition, an auxiliary water storage tank 11 is positioned at the bottom of the gravity direction of the cooling circuit, and the auxiliary water storage tank 11 has a first pipe connecting the fuel cell stack 3 and the heat exchanger 5 to each other. Branch inflow pipe LB1 and branch outflow pipe LB2 branched from L1 are respectively connected.

On the second pipe (L2) connecting the heat exchanger (5) and the upper water storage tank (7), the first shut-off valve (S1) for opening and closing the second pipe (L2) in accordance with the control signal of the controller (CU) Is mounted on the third pipe L3 connecting the upper water storage tank 7 and the fuel cell stack 3 to open and close the third pipe L3 according to a control signal of the controller CU. The second shut-off valve (S2) to be mounted.

In addition, a branch air pipe LB3 is configured in the third pipe L3 so as to branch from one side thereof to suck outside air, and on the branch air pipe LB3 according to a control signal of the controller CU, A third shutoff valve S3 for opening and closing the LB3) is mounted.

On the branch inlet pipe LB1 branched from one side of the first pipe L1 and connected to the auxiliary water storage tank 11, the branch inlet pipe LB1 is opened and closed according to a control signal of the controller CU. A fourth shut-off valve S4 is mounted and is branched from the other side of the first pipe L1 to the branch outlet pipe LB2 connected to the auxiliary water storage tank 11 according to the control signal of the controller CU. A fifth blocking valve S5 for opening and closing the branch outlet pipe LB2 is mounted.

In addition, the upper water storage tank 7 is equipped with a first water level sensor WS1 that detects the water level inside the tank and outputs a signal to the controller CU. On the first pipe L1, the water pump At one side between the fuel cell stack 3 and the fuel cell stack 3, a second water level sensor WS2 that detects the level of distilled water flowing in the first pipe L1 and outputs a signal to the controller CU is mounted.

Here, the first, second, third, fourth, fifth blocking valve (S1, S2, S3, S4, S5) is a solenoid valve for opening and closing each pipe in accordance with the control signal of the controller (CU), respectively Preferably, the auxiliary water storage tank 11, like the upper water storage tank 7, preferably comprises a heating unit (HU).

And the second shut-off valve (S2) is mounted on one side between the branch of the branch air pipe (LB3) and the upper water storage tank (7) on the third pipe (L3), the second water level sensor (WS2) is mounted on one side between the two points where the branch inlet pipe (LB1) and the branch outlet pipe (LB2) are respectively branched on the first pipe (L1).

The branch inlet pipe LB1 and the branch outlet pipe LB2 are branched from one side between the fuel cell stack 3 and the water pump 9 on the first pipe L1.

Therefore, the control operation of the thermal management system for fuel cells having the configuration as described above, the controller (CU) first receives a signal from the first water level sensor (WS1) to determine the amount of distilled water in the upper water storage tank (7) During the measurement, the first shutoff valve S1 and the second shutoff valve S2 are opened and controlled simultaneously with the operation of the fuel cell system, and the third shutoff valve S3 and the fourth shutoff valve S4 are closed-controlled. In each pipe including the fuel cell stack 3, water is filled for a set time.

As such, after filling the fuel cell stack 3 and each pipe with water, the controller CU drives the water pump 9 to circulate cooling water forcibly to cool the fuel cell stack 3. Is performed to maintain the activation temperature of the fuel cell stack 3.

In this way, when the system stops operating during the normal operation control, the controller CU continues to operate the water pump 9 and first closes and controls the second shutoff valve S2, and then the third shutoff valve. Opening control of S3 allows air in the atmosphere to be sucked through the branch air pipe LB3 and enter the pipe.

At this time, when water is not detected by the detection signal from the second water level sensor WS2, the controller CU closes and controls the first shutoff valve S1, thereby controlling the operation of the water pump 9. By terminating, operation termination control is performed.

As described above, when the water pump 9 is terminated by the operation end control, the controller (CU) controls the opening of the fourth shut-off valve (S4) to store the auxiliary distilled water remaining in the pipe using gravity using the gravity Gravity storage control to flow into the tank 11 to store is performed.

Of course, prior to the control process of the fuel cell thermal management system 1, the heating unit is configured in each of the upper water storage tank (7) and the auxiliary water storage tank (11) in an external environment in which the outside air temperature such as cold weather is lowered below zero. After the frozen distilled water is dissolved through the HU, the operation of the fuel cell thermal management system 1 is performed.

Here, the heating unit HU may be a conventional electric heater or a heat exchanger, and the like, and the distilled water stored in the auxiliary water storage tank 11 opens the fifth shutoff valve S5 when controlling the normal operation of the system. By controlling, it is allowed to flow into the water pump 9 to be recovered into the system.

As described above, according to the fuel cell thermal management system of the present invention, the size of the auxiliary water storage tank can be drastically reduced in designing the system to ensure the degree of freedom of the position of the components, and the position of other parts except the auxiliary water storage tank. Correlation can be installed regardless.

In addition, it is possible to completely remove residual distilled water by the auxiliary water tank, and to recover it again and to use it again, and to completely remove the residual distilled water, so that it does not damage the system or affect the cooling water flow even at subzero temperatures. It is effective in improving the low temperature startability of the system.

In addition, the system configuration can be simplified and minimizing power consumption, and the system configuration is simplified because no additional parts such as a water pump for conventional distilled water recovery are used. It can also increase the effect.

Further, by continuously operating the water pump, distilled water present in the separator plate of the fuel cell stack can be completely removed, and the fuel cell stack can be stored even at 0 ° C or lower.

Claims (7)

An upper water storage tank including a heating unit, a fuel cell stack, and a heat exchanger are connected to each other through a pipe, and a water pump is formed on a first pipe connecting the fuel cell stack and the heat exchanger to stack the fuel cell in the stack case. In the heat management system for a fuel cell comprising a cooling circuit for cooling the heat by a heat exchange method, An auxiliary water storage tank positioned at a lower portion with respect to the gravity direction of the cooling circuit and branched from a first pipe connecting the fuel cell stack and the heat exchanger to a branch inlet pipe and a branch outlet pipe; A first shut-off valve mounted on a second pipe connecting the heat exchanger and the upper water storage tank to open and close the second pipe according to a control signal of a controller; A second shut-off valve mounted on a third pipe connecting the upper water storage tank and the fuel cell stack to open and close the third pipe according to a control signal of a controller; A third shut-off valve mounted on a branch air engine configured to branch from one side of the third pipe to suck external air, and configured to open and close the branch air engine according to a control signal of a controller; A fourth shut-off valve mounted on the branch inlet pipe branched from one side of the first pipe and connected to the auxiliary water storage tank to open and close the branch inlet pipe according to a control signal of a controller; A fifth shut-off valve mounted on the branch outlet pipe connected to the auxiliary water storage tank branched from the other side of the first pipe and opening and closing the branch outlet pipe according to a control signal of a controller; A first water level sensor installed in the upper water storage tank to detect a water level inside the tank and output a signal to the controller; And A second water level sensor installed on one side between the water pump and the fuel cell stack on the first pipe to sense a water level inside the first pipe and output a signal to the controller; Thermal management system for a fuel cell comprising a. The method of claim 1, wherein the first, second, third, fourth, fifth blocking valve Thermal management system for a fuel cell, characterized in that consisting of a solenoid valve for opening and closing control of each pipe in accordance with the control signal of the controller. The storage tank of claim 1, wherein the auxiliary water storage tank is Thermal management system for a fuel cell comprising the heating unit. The method of claim 1, wherein the second shut-off valve On the third pipe, the thermal management system for a fuel cell, characterized in that mounted on one side between the branch branch engine branch and the upper water storage tank. The method of claim 1, wherein the second water level sensor Thermal management system for a fuel cell, characterized in that on the first pipe, the branch inlet pipe and the branch outlet pipe is mounted on one side between the two side points each branched. According to claim 1, wherein the branch inlet pipe and branch outlet pipe Thermal management system for a fuel cell on the first pipe, characterized in that each branched from one side between the fuel cell stack and the water pump. The method of claim 1, wherein the controller While measuring the quantity of water in the upper water storage tank from the first water level sensor, the first shutoff valve and the second shutoff valve are controlled to open at the same time as the fuel cell system is operated, and the third shutoff valve and the fourth shutoff valve are Thereafter, after filling the water in each pipe including the fuel cell stack for a predetermined time, the normal operation control for driving the water pump to force circulation of the cooling water to cool the fuel cell stack; During the normal operation control, when the system is stopped, the water pump is continuously operated, and the second shutoff valve is first controlled by closing, and the third shutoff valve is opened by controlling the air to be sucked into the pipe. And, if the water is not detected from the second water level sensor, the operation termination control to terminate the operation of the water pump, while closing the first shut-off valve; Gravity storage control to control the opening of the fourth shut-off valve when the water pump is finished by the operation end control, so that the remaining distilled water remaining in the pipe is stored in the auxiliary water storage tank by gravity; A thermal management system for a fuel cell, comprising control logic of the process.

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