Fuel cell cooling system

Abstract

To provide a cooling system for a fuel cell capable of attaining improvement of cooling capability by increasing a ventilation amount to a radiator while suppressing enlargement of a space.SOLUTION: A cooling system comprises: a cooling water circulation path which includes a fuel cell and a radiator and in which cooling water for adjusting a temperature of the fuel cell flows; and a radiator cooling path in which air exchanging heat with cooling water flowing in the radiator and passing the radiator flows. The radiator cooling path includes: a radiator discharge passage which is a passage of air padding the radiator; and a jet pump which utilizes a gas discharged from the fuel cell as a driving fluid. The radiator discharge passage is connected to the jet pump, and an intake fluid to the jet pump is made into air passing the radiator.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a system for cooling a fuel cell.

Background Art

[0002] Patent Document 1 discloses cooling a heat exchanger using a cooling fan. Patent Document 2 describes flowing at least a part of the exhaust air flow to a cooling structure and increasing the mass flow of outside air passing through the cooling structure by the jet pump principle, but there is no description regarding including the jet pump itself as a component. Patent Document 3 discloses mixing pure water with a jet pump when using the exhaust air of a fuel cell as the cooling air of a radiator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is known that fuel cell cooling systems include a radiator, which is a heat exchanger that releases heat to the outside from the refrigerant (cooling water) that has acquired heat by cooling the fuel cell. Therefore, the ability of the radiator to cool the refrigerant is important. On the other hand, miniaturization of the radiator is also desired to save space, and increasing the airflow to the radiator to increase its cooling capacity is an effective way to achieve this. To do this, it is effective to increase the space before and after the radiator to reduce airflow resistance. However, in reality, various components are integrated in order to miniaturize the entire fuel cell system, so it is not possible to have such a large space. Furthermore, when fuel cell systems are used in mobile devices such as vehicles, ventilation due to vehicle speed can be expected, but because many components are located behind the radiator, it is difficult to obtain the same amount of ventilation as the vehicle speed. Therefore, a radiator fan is essential whether installed in a mobile device or in a stationary device such as equipment, but the increased ventilation resistance due to component integration necessitates further measures to improve cooling capacity.

[0005] In light of the above issues, this disclosure aims to provide a fuel cell cooling system that can improve cooling capacity by increasing the amount of airflow to the radiator while suppressing the expansion of space. [Means for solving the problem]

[0006] The present invention discloses a cooling system for a fuel cell, comprising a fuel cell and a radiator, a cooling water circulation path through which cooling water flows to regulate the temperature of the fuel cell, and a radiator cooling path through which air that has passed through the radiator and exchanged heat with the cooling water flowing through the radiator flows, wherein the radiator cooling path comprises a radiator discharge path which is a passage for air that has passed through the radiator, and a jet pump that uses the gas discharged from the fuel cell as a driving fluid, the radiator discharge path is connected to the jet pump, and the intake fluid to the jet pump is air that has passed through the radiator.

[0007] The present invention discloses a cooling system for a fuel cell, comprising a fuel cell, a first radiator, and a second radiator arranged in series or parallel with the first radiator, the system including a cooling water circulation path through which cooling water flows to regulate the temperature of the fuel cell, and a radiator cooling path through which air that has passed through the second radiator and exchanged heat with the cooling water flowing through the second radiator flows, wherein the radiator cooling path includes a radiator discharge path which is a passage for air that has passed through the second radiator, and a jet pump that uses the gas discharged from the fuel cell as a driving fluid, the radiator discharge path is connected to the jet pump, and the intake fluid for the jet pump is air that has passed through the second radiator.

[0008] The second radiator may have a lower cooling capacity than the first radiator. [Effects of the Invention]

[0009] According to this disclosure, the gas (air) discharged from the fuel cell can be used as the driving fluid for the jet pump, driving the air that has passed through the radiator to increase the flow rate. This allows for an increase in the amount of air supplied to the radiator while suppressing the expansion of space, thereby improving the cooling capacity. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a conceptual diagram of the configuration of the fuel cell cooling system 10. [Figure 2] Figure 2 is a schematic diagram showing the configuration of the jet pump 24. [Figure 3] Figure 3 is a diagram illustrating the arrangement of the second radiator 30. [Figure 4] Figure 4 is a diagram illustrating the arrangement of the second radiator 30. [Figure 5] Figure 5 is a diagram illustrating the arrangement of the second radiator 30. [Modes for carrying out the invention]

[0011] 1. Form 1 FIG. 1 conceptually shows the configuration of a fuel cell cooling system 10 according to Embodiment 1. A fuel cell system equipped with such a fuel cell cooling system 10 is mounted, for example, on a vehicle that drives a motor with a fuel cell or on a stationary power generation facility. The fuel cell cooling system 10 of this embodiment has a cooling water circulation path 11 and a radiator cooling path 21.

[0012] 1.1. Cooling water circulation path The cooling water circulation path 11 is a path through which cooling water for adjusting the temperature of the fuel cell, such as cooling the fuel cell 13, circulates. The cooling water circulation path 11 includes a cooling water pump 12, a fuel cell 13, a valve 14, and a radiator 15, and these are connected by pipes so that the cooling water circulates.

[0013] The cooling water pump 12 is a pump for circulating cooling water in the cooling water circulation path 11, and a known one can be used.

[0014] The fuel cell 13 is configured as a fuel cell stack formed by stacking a required number of single cells that generate electricity through an electrochemical reaction by receiving supply of hydrogen gas and air from a path not shown. The power generated by the fuel cell 13 is used for the purpose of the fuel cell system. A known fuel cell can be used.

[0015] The valve 14 is a three-way valve and can be switched by a signal. By this valve 14, it is possible to switch whether to flow cooling water to the radiator 15 or not. In particular, when warming up the fuel cell 13 during low-temperature startup or the like, it is effective to raise the temperature without flowing cooling water to the cooled radiator 15.

[0016] [[ID=2,4]]

[0017] ​In such a cooling water circulation path 11, cooling water is sent to the fuel cell 13 by the cooling water pump 12 to cool the fuel cell 13. The cooling water heated by the fuel cell 13 passes through the valve 14 and reaches the radiator 15, and after being cooled by the radiator 15, it returns to the cooling water pump 12. The fuel cell 13 is cooled by such a circulation of the cooling water.

[0018] 1.2. Radiator Cooling Path The radiator cooling path 21 is a path for sending air to the radiator 15 to cool the cooling water by causing heat exchange between the cooling water flowing through the internal flow path of the radiator 15 and the air. As can be seen from FIG. 1, the radiator cooling path 21 includes a radiator discharge flow path 22, a fuel cell off-gas flow path 23, and a jet pump 24.

[0019] The radiator discharge flow path 22 is an air flow path through which the air that has passed through the radiator 15 flows toward the jet pump 24. The air flowing through the radiator discharge flow path 22 flows into the jet pump 24 as a suction fluid and is driven by the driving fluid from the fuel cell off-gas flow path 23. Therefore, the radiator discharge flow path 22 is a flow path connected from the air outlet side of the radiator 15 to the jet pump 24. Also, the radiator discharge flow path 22 may be connected so as to be close to the back surface (the side where air flows out) of the radiator 15, but it may be arranged at a certain distance as long as the influence on the amount of air passing through the radiator 15 is small. The latter enables reduction of the assembly man-hours of parts and improvement of workability. In addition, the radiator discharge flow path 22 may cover the entire back surface of the radiator 15 or may cover it partially. In the latter case, it is desirable to make it an area that is effective in increasing the amount of air passing through the radiator 15, such as the inlet side or the outlet side of the cooling water flow path, in terms of the design of the radiator 15.

[0020] The fuel cell off-gas passage 23 is a passage through which air (a gas called off-gas) that has been supplied to the fuel cell 13 and then discharged without being used flows toward the jet pump 24. The air flowing through the fuel cell off-gas passage 23 flows into the jet pump 24 as a driving fluid and drives the intake fluid from the radiator discharge passage 22. Therefore, the fuel cell off-gas passage 23 is a passage that connects the air outlet of the fuel cell 13 to the jet pump 24 (connected to the nozzle 25 of the jet pump 24). A pressure regulating valve is typically provided at the air outlet of the fuel cell 13 to maintain the pressure of the reaction air inside the fuel cell 13. This pressure regulating valve ensures that the air discharged from the fuel cell 13 has a high flow velocity, which can then be sent to the jet pump 24 to form a jet flow. Alternatively, the pressure regulating valve may be integrated into the jet pump 24, so that the valve itself acts as a nozzle for the driving fluid. However, the air supplied to the jet pump 24 as the driving fluid is not limited to the off-gas from the fuel cell 13. It may be taken in by branching off from the piping supplying air to the fuel cell 13, or a separate air intake may be provided. It may also be a mixture of the above off-gas and these.

[0021] The jet pump 24, sometimes called an ejector, has a nozzle 25 and a diffuser 26. Figure 2 schematically shows the configuration of the jet pump 24. In the jet pump 24, by releasing the pressure of the gas (driving fluid) injected from the nozzle 25, surrounding gas (intake fluid) is drawn in and the total gas flow rate can be increased. In this configuration, a fuel cell off-gas passage 23 is connected to the nozzle 25, and the off-gas is injected from the nozzle 25 as the driving fluid towards the diffuser 26. This draws in and increases the gas from the radiator discharge passage 22 (air that has passed through the radiator) as the intake fluid, thereby increasing the airflow rate passing through the radiator 15 and improving the cooling capacity of the radiator 15. This also makes it possible to eliminate or miniaturize the fan that was conventionally used to cool the radiator. The basic shapes of the nozzle 25 and diffuser 26 can be those of known design. The specific dimensions are not particularly limited as long as negative pressure is generated by the kinetic energy of the driving fluid, drawing in the surrounding fluid (intake fluid) and increasing the fluid flow rate. As an example, the nozzle diameter d can be approximately 4.0 to 4.5 cm, and the diffuser diameter D can be approximately 10 to 15 cm. Furthermore, the position of the jet pump 24 is not particularly limited and can be adjusted as appropriate in relation to other equipment. It may be located near the air outlet side of the radiator 15 (in which case the radiator discharge passage 22 will be shortened), or near the fuel cell 13 (in which case the fuel cell off-gas passage 23 will be shortened).

[0022] In the radiator cooling path 21 described above, the jet pump 24 sucks in the air that has passed through the radiator 15, thereby increasing the airflow rate passing through the radiator 15 and improving the cooling capacity of the radiator 15. In this configuration, even without providing special spaces in front of or behind the radiator 15 (even if components are clustered together), sufficient airflow can be ensured to increase the cooling capacity of the radiator. Furthermore, there are no constraints on the radiator's mounting position, such as placing it at the front of the vehicle where it is easier to take in airflow at vehicle speed, allowing for greater flexibility in the shape and mounting of the radiator grille. In addition, the radiator fan can be eliminated or made smaller.

[0023] 2. Form 2 While Embodiment 1 was an example equipped with one radiator 15, Embodiment 2 describes an example in which a secondary radiator 30 with a lower cooling capacity than the radiator 15 is provided, and the radiator cooling path 21 described above is arranged in the secondary radiator 30. As a result, in addition to the effects described above, by arranging the radiator cooling path 21 in the secondary radiator 30 with a lower cooling capacity, the airflow rate necessary to improve cooling efficiency can be more reliably secured. In the fuel cell cooling system 10 of form 2, the basic configuration is the same as in form 1, except that the radiator cooling path 21 is located in the second radiator 30. Therefore, the same reference numerals are used and the explanation is omitted here. Below, examples of forms differing in the location where the second radiator 30 is located will be described.

[0024] 2.1.Form 2-1 Figure 3 shows a configuration in which the second radiator 30 is installed in parallel with the radiator 15 (first radiator). By installing them in parallel in this way, the increase in pressure loss in the cooling system can be suppressed. In Figure 3(a), the second radiator 30 is branched off from the piping before and after the radiator 15. This makes it easy to change the piping configuration when adding the second radiator 30. In Figure 3(b), the second radiator 30 is branched off on the coolant outlet side of the fuel cell 13.

[0025] 2.2.Form 2-2 Figure 4 shows a configuration in which the second radiator 30 is installed in series with respect to the radiator 15 (first radiator). In a series configuration, the amount of additional piping required for installation can be kept to a minimum compared to the parallel configuration described above. In Figure 4(a), the second radiator 30 is installed between the valve 14 and the radiator 15, and in Figure 4(b), the second radiator 30 is installed between the fuel cell 13 and the valve 14.

[0026] 2.3.Form 2-3 In the example shown in Figure 5, a throttle valve 31 is placed in series between the fuel cell 13 and the valve 14, and the second radiator 30 is installed in parallel with this throttle valve 31. The throttle valve 31 is a valve that can adjust the flow rate steplessly, and by adjusting the throttle of the throttle valve 31, it is possible to adjust the amount of cooling water supplied to the second radiator 30. According to this, the amount of additional piping required for installation can be kept to a minimum compared to the parallel installation shown in Figure 3, and the increase in pressure loss in the cooling system can be suppressed compared to when the first and second radiators are installed in series. [Explanation of symbols]

[0027] 10…Fuel cell cooling system, 11…Cooling water circulation path, 12…Cooling water pump, 13…Fuel cell, 14…Valve, 15…Radiator, 21…Radiator cooling path, 22…Radiator discharge path, 23…Fuel cell off-gas path, 24…Jet pump, 25…Nozzle, 26…Diffuser, 30…Second radiator

Claims

1. It has a fuel cell and a radiator, and a cooling water circulation path through which cooling water flows to regulate the temperature of the fuel cell, The system includes a radiator cooling path through which air that has passed through the radiator and exchanged heat with the coolant flowing through the radiator flows, The aforementioned radiator cooling path is, The radiator discharge channel is a passage for the air that has passed through the radiator, The system includes a jet pump that uses the gas discharged from the fuel cell as a driving fluid, The radiator discharge passage is connected to the jet pump, and the intake fluid to the jet pump is the air that has passed through the radiator. Cooling system for fuel cells.

2. A fuel cell, a first radiator, and a second radiator arranged in series or parallel with the first radiator, and a cooling water circulation path through which cooling water flows to regulate the temperature of the fuel cell, The system includes a radiator cooling path through which air that has passed through the second radiator and exchanged heat with the coolant flowing through the second radiator flows, The aforementioned radiator cooling path is, The radiator discharge channel is the air passage through which the air has passed through the second radiator, The system includes a jet pump that uses the gas discharged from the fuel cell as a driving fluid, The radiator discharge passage is connected to the jet pump, and the intake fluid to the jet pump is the air that has passed through the second radiator. Cooling system for fuel cells.

3. The fuel cell cooling system according to claim 2, wherein the second radiator has a lower cooling capacity than the first radiator.

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