Cooling system for fuel cell

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] The present disclosure relates to a system for cooling a fuel cell. [Background technology]

[0002] Patent Document 1 discloses cooling a heat exchanger using a cooling fan. Patent document 2 describes flowing at least a portion of the exhaust air flow into a cooling structure and increasing the mass flow of outside air passing through the cooling structure using the jet pump principle, but does not describe including the jet pump itself as a component. Patent Document 3 discloses that when exhaust air from a fuel cell is used as cooling air for a radiator, pure water is mixed into the exhaust air by a jet pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-323862 A [Patent Document 2] JP 2017-500683 A [Patent Document 3] JP 2002-184419 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is known that a system for cooling a fuel cell is provided with a radiator, which is a heat exchanger that releases heat from the coolant (cooling water) that has acquired heat by cooling the fuel cell to the outside. Therefore, the radiator's ability to cool the coolant is important. On the other hand, it is also desirable to make the radiator more compact to save space, and an effective way to do this is to increase the radiator's airflow and improve its cooling capacity. To achieve this, it is effective to leave a large space in front of and behind the radiator to reduce airflow resistance. However, in reality, it is not possible to leave such a large space because various parts are integrated to make the entire fuel cell system smaller. In addition, when a fuel cell system is used in a moving object such as a vehicle, ventilation due to the vehicle speed can be expected, but since many parts are arranged behind the radiator, it is difficult to obtain the same amount of ventilation as the vehicle speed. Therefore, a radiator fan is essential whether the system is installed in a moving object or in a stationary object such as equipment, but ventilation resistance increases due to the integration of parts, and a means of further improving cooling capacity is necessary.

[0005] In view of the above problems, the present disclosure has an object to provide a cooling system for a fuel cell that can increase the amount of air flow to the radiator while suppressing an increase in space, thereby improving the cooling capacity. [Means for solving the problem]

[0006] The present application discloses a fuel cell cooling system having a fuel cell and a radiator, comprising a cooling water circulation path through which cooling water flows to adjust the temperature of the fuel cell, and a radiator cooling path through which air flows that has passed through the radiator after exchanging heat with the cooling water flowing through the radiator, the radiator cooling path having a radiator exhaust flow path which is a flow path for air that has passed through the radiator, and a jet pump that uses gas exhausted from the fuel cell as a driving fluid, the radiator exhaust flow path being connected to the jet pump, and the intake fluid to the jet pump being air that has passed through the radiator.

[0007] The present application discloses a cooling system for a fuel cell having a fuel cell, a first radiator, and a second radiator arranged in series or parallel to the first radiator, and comprising a cooling water circulation path through which cooling water flows for regulating the temperature of the fuel cell, and a radiator cooling path through which air flows that has exchanged heat with the cooling water flowing through the second radiator and passed through the second radiator, the radiator cooling path having a radiator exhaust flow path which is a flow path for air that has passed through the second radiator, and a jet pump that uses gas exhausted from the fuel cell as a driving fluid, the radiator exhaust flow path being connected to the jet pump, and the intake fluid to the jet pump being air that has passed through the second radiator.

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

[0009] According to the present disclosure, the gas (air) discharged from the fuel cell can be used as the driving fluid for the jet pump, driving the air passing through the radiator and increasing the flow rate, thereby increasing the amount of air passing through the radiator while suppressing expansion of the space, thereby improving cooling capacity. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual diagram of the configuration of a cooling system 10 for a fuel cell. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of the jet pump 24. As shown in FIG. [Diagram 3] FIG. 3 is a diagram illustrating the arrangement of the second radiator 30. As shown in FIG. [Figure 4] FIG. 4 is a diagram illustrating the arrangement of the second radiator 30. As shown in FIG. [Diagram 5] FIG. 5 is a diagram illustrating the arrangement of the second radiator 30. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1. Form 1 1 conceptually illustrates 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 using 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 circulates to adjust the temperature of the fuel cell, such as by cooling the fuel cell 13, and is equipped with a cooling water pump 12, a fuel cell 13, a valve 14, and a radiator 15, and these are connected by piping to circulate the cooling water.

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

[0014] The fuel cell 13 is configured as a fuel cell stack made up of a required number of single cells that receive hydrogen gas and air from paths (not shown) and generate electricity through an electrochemical reaction. The electricity generated by the fuel cell 13 is used for the purpose of the fuel cell system. Any known fuel cell can be used.

[0015] Valve 14 is a three-way valve that can be switched by a signal. This valve 14 can switch between flowing and not flowing cooling water to radiator 15, which is particularly effective when warming up fuel cell 13 during low-temperature startup, because it allows the temperature to rise without flowing cooling water to cold radiator 15.

[0016] The radiator 15 is a heat exchanger that cools the cooling water heated by cooling the fuel cell 13 by exchanging heat with air supplied through a radiator cooling path 21. Therefore, a known type can be used as the radiator 15, and known heat exchangers can be applied.

[0017] In this type of 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, and the cooling water heated in the fuel cell 13 passes through a valve 14 to reach a radiator 15, where it is cooled before returning to the cooling water pump 12. The fuel cell 13 is cooled by circulating the cooling water in this manner.

[0018] 1.2.Radiator cooling path The radiator cooling path 21 is a path for cooling the coolant by sending air to the radiator 15 and performing heat exchange between the air and the coolant flowing through the internal flow path of the radiator 15. As can be seen from FIG 1, the radiator cooling path 21 includes a radiator exhaust 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 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 an intake 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 that is connected from the air outlet side of the radiator 15 to the jet pump 24. Also, the radiator exhaust flow passage 22 may be connected close to the back surface (the side from which air flows out) of the radiator 15, but may be disposed at a slight distance as long as there is substantially little effect on the amount of air passing through the radiator 15. The latter arrangement makes it possible to reduce the number of assembly steps and improve workability. Alternatively, the radiator discharge passage 22 may cover the entire back surface of the radiator 15, or may cover only a part of it. In the latter case, it is desirable to cover an area where it is effective to increase the amount of air passing through the radiator 15, such as the inlet or outlet side of the cooling water passage, in terms of the design of the radiator 15.

[0020] The fuel cell off-gas flow path 23 is a flow path through which air (a gas called off-gas) that is 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 flow path 23 flows into the jet pump 24 as a driving fluid, and drives the intake fluid from the radiator discharge flow path 22. Therefore, the fuel cell off-gas flow path 23 is a flow path that is connected from the air exhaust port 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 usually provided at the outlet on the air exhaust side of the fuel cell 13 to maintain the pressure of the reactant air inside the fuel cell 13. This pressure regulating valve increases the flow rate of the air exhausted from the fuel cell 13, and by sending this air to the jet pump 24, a jet flow can be formed by the jet pump 24. Note that the pressure regulating valve may be incorporated into the jet pump 24, and the pressure regulating valve itself may be configured 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, but may be taken in by branching off from the piping for supplying air to the fuel cell 13, or a separate air intake port may be provided. The air may also be a mixture of the off-gas and these.

[0021] The jet pump 24 is sometimes called an ejector, and has a nozzle 25 and a diffuser 26. The configuration of the jet pump 24 is shown in schematic form in FIG. In the jet pump 24, by releasing the pressure of the gas (driving fluid) injected from the nozzle 25, the surrounding gas (suction fluid) is entrained and sucked in, thereby making it possible to increase the total gas flow rate. In this embodiment, the fuel cell off-gas flow path 23 is connected to the nozzle 25, and the off-gas is injected from the nozzle 25 as the driving fluid toward the diffuser 26. This allows the gas (air that has passed through the radiator) from the radiator discharge flow path 22 to be entrained and sucked in as the suction fluid, increasing the flow rate of air passing through the radiator 15 and improving the cooling capacity of the radiator 15. This also makes it possible to eliminate or reduce the size of the fan that has been conventionally used to cool the radiator. Known basic shapes can be applied to the nozzle 25 and the diffuser 26. There are no particular limitations on the specific dimensions as long as the kinetic energy of the driving fluid can generate negative pressure and draw in the surrounding fluid (suction fluid) to increase the fluid flow rate, but as an example, the nozzle diameter d can be about 4.0 to 4.5 cm and the diffuser diameter D can be about 10 to 15 cm. The position of the jet pump 24 is not particularly limited, and can be adjusted appropriately in relation to other devices. It may be near the air outlet side of the radiator 15 (in this case, the radiator exhaust flow path 22 will be short) or near the fuel cell 13 (in this case, the fuel cell off-gas flow path 23 will be short).

[0022] In the above-described radiator cooling path 21, the jet pump 24 draws in the air that has passed through the radiator 15 as described above, thereby increasing the flow rate of the air passing through the radiator 15, thereby making it possible to improve the cooling capacity of the radiator 15. In this case, even if no special space is provided in front of or behind the radiator 15 (even if the components are arranged in an integrated manner), the amount of ventilation can be secured and the amount of cooling by the radiator can be increased. Furthermore, there is no restriction on the mounting position of the radiator, such as the front of the vehicle where wind at vehicle speed can easily be drawn in, so the shape of the radiator grille and the degree of freedom in mounting can be increased. In addition, the radiator fan can be eliminated or made smaller.

[0023] 2. Form 2 While the first embodiment is an example equipped with one radiator 15, the second embodiment will be described with an example equipped with a secondary second radiator 30 having a cooling capacity lower than that of the radiator 15, and arranging the above-mentioned radiator cooling path 21 in the second radiator 30. In addition to the above-mentioned effects, by arranging the radiator cooling path 21 in the second radiator 30 having a lower cooling capacity, the air flow rate required to enhance the cooling efficiency can be more reliably secured. In the fuel cell cooling system 10 of the second embodiment, the basic configuration is the same as that of the first embodiment except that the radiator cooling path 21 is disposed in the second radiator 30. Therefore, the same reference numerals are used and the description is omitted here. Below, an example of the embodiment according to the difference in the position where the second radiator 30 is disposed will be described.

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

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

[0026] 2.3.Form 2-3 5, a throttle valve 31 is disposed in series between the fuel cell 13 and the valve 14, and the second radiator 30 is installed in parallel to 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 to the second radiator 30. This allows the amount of additional piping required for installation to be kept short compared to the parallel installation shown in Figure 3, and prevents an increase in pressure loss in the cooling system compared to when the first radiator and second radiator 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 exhaust flow path, 23...fuel cell off-gas flow path, 24...jet pump, 25...nozzle, 26...diffuser, 30...second radiator

Claims

1. a cooling water circulation path having a fuel cell and a radiator, through which cooling water for regulating the temperature of the fuel cell flows; and a radiator cooling path through which air that has exchanged heat with the cooling water flowing through the radiator and passed through the radiator flows; The radiator cooling path is a radiator exhaust flow path which is a flow path of the air that has passed through the radiator; 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 air that has passed through the radiator is used as an intake fluid to the jet pump. Fuel cell cooling system.

2. a cooling water circulation path including a fuel cell, a first radiator, and a second radiator arranged in series or in parallel with the first radiator, through which cooling water for adjusting the temperature of the fuel cell flows; and a radiator cooling path through which air that has exchanged heat with the cooling water flowing through the second radiator and passed through the second radiator flows, The radiator cooling path is a radiator discharge flow path which is a flow path of the air that has passed through the second radiator; 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 air that has passed through the second radiator is used as an intake fluid to the jet pump; Fuel cell cooling system.

3. 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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