Fuel cell cooling unit

Abstract

To enable a fuel cell cooling system to be used in a wider variety of forms.SOLUTION: A fuel cell cooling unit includes a primary coolant circuit through which a coolant circulates, a fuel cell cooled by the coolant flowing through a primary coolant circuit, and a heat exchanger. The heat exchanger has a primary flow path and a secondary flow path, the primary flow path constitutes a part of the primary coolant circuit, and heat is exchanged between the primary flow path and the secondary flow path. A connection structure that allows piping to be attached and detached is provided at each of the upstream and downstream ends of the secondary flow path.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a fuel cell cooling unit.

[0002] There is known a fuel cell cooling system that cools a fuel cell using a radiator. This type of fuel cell cooling system has a coolant circulation path through which a coolant circulates. The coolant cooled by the radiator is supplied to the fuel cell via the coolant circulation path, thereby cooling the fuel cell. To ensure insulation between the fuel cell and the radiator, a material with low electrical conductivity is used as the coolant.

[0003] Cited Document 1 discloses a fuel cell cooling system in which a fuel cell side refrigerant circulation path (hereinafter referred to as a primary refrigerant circulation path) and a radiator side refrigerant circulation path (hereinafter referred to as a secondary refrigerant circulation path) are independent. This fuel cell cooling system is provided with a heat exchanger that exchanges heat between the primary refrigerant circulation path and the secondary refrigerant circulation path. This configuration can further improve the insulation between the fuel cell and the radiator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-98553 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, fuel cell cooling systems from the radiator to the fuel cell have been provided as a single unit by manufacturers. However, this type of provision can make it difficult to accommodate the diversification of fuel cell usage patterns. This specification proposes technology that enables the fuel cell cooling system to be used in a wider variety of ways. [Means for solving the problem]

[0006] The fuel cell cooling unit disclosed in this specification includes a primary refrigerant circuit through which a refrigerant circulates, a fuel cell cooled by the refrigerant flowing in the primary refrigerant circuit, and a heat exchanger. The heat exchanger has a primary flow path and a secondary flow path, and the primary flow path forms a part of the primary refrigerant circuit, and exchanges heat between the primary flow path and the secondary flow path. A connection structure that allows detachable piping is provided at each of the upstream and downstream ends of the secondary flow path.

[0007] In this fuel cell cooling unit, a user can use the fuel cell cooling unit by connecting a secondary refrigerant circulation path (i.e., a refrigerant circulation path on the radiator side) to the secondary flow path. That is, in this configuration, a user can prepare a secondary refrigerant circulation path. Since the primary flow path constituting the primary refrigerant circulation path and the secondary flow path constituting the secondary refrigerant circulation path are independent, insulation is ensured between the primary refrigerant circulation path and the secondary refrigerant circulation path. Therefore, a user can connect the secondary refrigerant circulation path to the fuel cell cooling unit without considering the insulation of the secondary refrigerant circulation path. Also, since the primary flow path and the secondary flow path are independent, the pressure distribution in the secondary refrigerant circulation path does not affect the pressure distribution in the primary refrigerant circulation path. Therefore, a user can connect the secondary refrigerant circulation path to the fuel cell cooling unit without considering the pressure distribution in the primary refrigerant circulation path. In this way, a user can provide a secondary refrigerant circulation path without being restricted by insulation or pressure distribution in the primary refrigerant circulation path. Therefore, according to this fuel cell cooling unit, a fuel cell cooling system can be constructed in various forms.

[0008] This specification also proposes a fuel cell cooling system in which the conductivity of the coolant can be easily controlled. The second fuel cell cooling system has a primary coolant circuit through which a coolant circulates, a fuel cell cooled by the coolant flowing in the primary coolant circuit, a secondary coolant circuit through which a coolant circulates, a radiator that cools the coolant flowing in the secondary coolant circuit, and a heat exchanger. The heat exchanger has a primary flow path and a secondary flow path, the primary flow path constitutes a part of the primary coolant circuit, the secondary flow path constitutes a part of the secondary coolant circuit, and heat is exchanged between the primary flow path and the secondary flow path. The conductivity of the coolant in the secondary coolant circuit is higher than the conductivity of the coolant in the primary coolant circuit.

[0009] In this fuel cell cooling system, insulation between the fuel cell and the secondary refrigerant circuit is ensured by the independence of the primary refrigerant circuit and the low electrical conductivity of the refrigerant in the primary refrigerant circuit. Therefore, even if the electrical conductivity of the refrigerant in the secondary refrigerant circuit is high, insulation between the radiator and the fuel cell can be ensured. Furthermore, since there is no problem even if the electrical conductivity of the refrigerant in the secondary refrigerant circuit is high, no process is required to reduce the electrical conductivity of the refrigerant in the secondary refrigerant circuit (for example, a process to remove ions from the refrigerant). Therefore, in this fuel cell cooling system, it is easy to manage the electrical conductivity of the refrigerant. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a configuration diagram of a fuel cell cooling system 100. [Diagram 2] FIG. 4 is a diagram showing the connection between the pump 50 and the heat exchanger 30. [Diagram 3] FIG. 11 is a configuration diagram of a fuel cell cooling system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The above-mentioned fuel cell cooling unit or fuel cell cooling system may have a parallel flow path connected in parallel to a fuel cell flow path, which is a portion of the primary coolant circulation path that passes through the fuel cell, and an ion exchanger that removes ions from the coolant in the parallel flow path. When a coolant is circulating in the primary coolant circulation path, the coolant may always flow in the fuel cell flow path and the parallel flow path.

[0012] According to this configuration, an increase in the conductivity of the refrigerant in the primary refrigerant circulation path can be prevented.

[0013] The above-mentioned fuel cell cooling unit or fuel cell cooling system may further include a pump for circulating the coolant through the primary coolant circuit, and a discharge port of the pump may be connected to the upstream end of the primary flow path by a flange connection.

[0014] According to this configuration, the connection strength at the discharge port of the pump is improved, so that the discharge pressure of the pump can be increased.

[0015] The above-mentioned fuel cell cooling unit or fuel cell cooling system may further include a bypass flow path connecting the upstream and downstream portions of the secondary flow path relative to the heat exchanger, and an intercooler provided in the bypass flow path and cooling the air supplied to the fuel cell.

[0016] With this configuration, it is possible to prevent ions from eluting from the intercooler into the refrigerant in the primary refrigerant circulation path.

[0017] The fuel cell cooling unit 10 shown in Fig. 1 is incorporated into a fuel cell cooling system 100. The fuel cell cooling unit 10 has a fuel cell 20. The fuel cell cooling system 100 is mounted on an electric vehicle. The fuel cell 20 is supplied with hydrogen from a tank (not shown) and with compressed air from a compressor (not shown). The fuel cell 20 generates electricity by reacting hydrogen with oxygen in the compressed air, and supplies the generated electricity to a traction motor of the electric vehicle.

[0018] The fuel cell cooling unit 10 is a product configured to be distributed. The parts of the fuel cell cooling system 100 other than the fuel cell cooling unit 10 (i.e., the radiator 110, the pipes 122, 124, etc.) are components that are subsequently connected to the fuel cell cooling unit 10.

[0019] The fuel cell cooling unit 10 has a heat exchanger 30 and a primary refrigerant circulation path 40. The heat exchanger 30 has a primary flow path 31 and a secondary flow path 32. The heat exchanger 30 exchanges heat between the primary flow path 31 and the secondary flow path 32. The primary refrigerant circulation path 40 is an annular flow path in which a refrigerant circulates. The primary refrigerant circulation path 40 is composed of the primary flow path 31 of the heat exchanger 30, a pipe 42, a fuel cell flow path 22 provided inside the fuel cell 20, and a pipe 44. The pipe 42 connects the downstream end of the primary flow path 31 to the upstream end of the fuel cell flow path 22. The pipe 44 connects the downstream end of the fuel cell flow path 22 to the upstream end of the primary flow path 31. A pump 50 is provided between the pipe 44 and the primary flow path 31. The pump 50 pumps the refrigerant from the pipe 44 toward the primary flow path 31. When the pump 50 is operated, the refrigerant flows in the order of the primary flow path 31, the pipe 42, the fuel cell flow path 22, and the pipe 44. That is, the refrigerant circulates within the primary refrigerant circulation path 40 .

[0020] FIG. 2 shows a connection between the pump 50 and the heat exchanger 30 (i.e., the upstream end of the primary flow path 31). As shown in FIG. 2, the discharge port 50a of the pump 50 is connected to the upstream end of the primary flow path 31 by a flange connection. Although not shown, a gasket is disposed on the sealing surface between the pump 50 and the heat exchanger 30 to prevent leakage of the refrigerant. In general, the discharge port of the pump is connected to the heat exchanger via a rubber hose. In this case, the pressure resistance of the rubber hose is low, so the discharge pressure of the pump is limited. In contrast, when the discharge port 50a of the pump 50 is connected to the heat exchanger 30 (i.e., the primary flow path 31) by a flange connection as shown in FIG. 2, the strength of the connection is high, so the discharge pressure of the pump 50 can be increased. By increasing the discharge pressure of the pump 50, the suction side pressure of the pump 50 is also increased, and the occurrence of cavitation and the collapse of the piping 44 (e.g., a rubber hose) due to negative pressure can be suppressed. In this way, the use of a flange connection can expand the pressure range in which the pump 50 can operate.

[0021] The frame of the body of the electric vehicle is used as an electrical ground point. The housing of the heat exchanger 30 and the housing of the pump 50 are connected to the frame of the electric vehicle by an earth wire (i.e., grounded). On the other hand, the fuel cell 20 is a power source and is insulated from the frame of the electric vehicle. Therefore, the fuel cell 20 needs to be insulated from the heat exchanger 30 and the pump 50. In the fuel cell cooling unit 10, the pipes 42, 44 are made of insulating materials (e.g., rubber hoses). Also, in the fuel cell cooling unit 10, the conductivity of the refrigerant flowing in the primary refrigerant circulation path 40 is low. For this reason, the fuel cell 20 is insulated from the heat exchanger 30 and the pump 50.

[0022] As shown in FIG. 1, the fuel cell cooling unit 10 has a parallel flow path 62 and an ion exchanger 60. The parallel flow path 62 is connected to the primary refrigerant circulation path 40 at each position upstream and downstream of the heat exchanger 30. The parallel flow path 62 is connected in parallel to the fuel cell flow path 22. The ion exchanger 60 is provided in the parallel flow path 62. No valve is provided in the parallel flow path 62. Therefore, when the pump 50 is operating and the refrigerant is circulating in the primary refrigerant circulation path 40, the refrigerant always flows in the fuel cell flow path 22 and the parallel flow path 62. The ion exchanger 60 removes ions from the refrigerant flowing in the parallel flow path 62. Ions are eluted into the refrigerant in the primary refrigerant circulation path 40 from each component (i.e., piping, etc.) that constitutes the primary refrigerant circulation path 40. The ion exchanger 60 suppresses an increase in the ion concentration in the refrigerant by removing ions from the refrigerant. This prevents the electrical conductivity of the coolant in the primary coolant circulation path 40 from increasing, and maintains the insulation of the fuel cell 20 from the heat exchanger 30 and the pump 50 .

[0023] The fuel cell cooling unit 10 has a reservoir tank 70. The reservoir tank 70 is connected to the primary refrigerant circulation path 40 at positions upstream and downstream of the heat exchanger 30. The reservoir tank 70 stores surplus refrigerant in the primary refrigerant circulation path 40.

[0024] The secondary flow passage 32 of the heat exchanger 30 is configured with a pipe 32a at a portion upstream of the heat exchanger 30. The secondary flow passage 32 of the heat exchanger 30 is configured with a pipe 32b at a portion downstream of the heat exchanger 30. The pipes 32a and 32b are configured with a rigid body such as resin. The fuel cell cooling unit 10 has a bypass flow passage 82 and an intercooler 80. The bypass flow passage 82 connects the pipe 32a to the pipe 32b. The intercooler 80 cools the compressed air supplied to the fuel cell 20 by heat exchange with the refrigerant flowing through the bypass flow passage 82. The pipe 32a is provided with a connection structure that allows an external pipe to be attached and detached. The pipe 32b is provided with a connection structure that allows an external pipe to be attached and detached. As these connection structures, a bolt-type connection structure or a connector-type connection structure can be adopted. The bolt-type connection structure is a structure in which pipes are connected to each other by fastening bolts. The connector-type connection structure is a connection structure in which the pipes can be switched between an engaged state and a disengaged state by the movement of a movable member. A pump 150, which will be described later, is detachably connected to the pipe 32a. A pipe 122, which will be described later, is detachably connected to the pipe 32b.

[0025] The fuel cell cooling system 100 includes a radiator 110, pipes 122 and 124, and a pump 150 in addition to the fuel cell cooling unit 10. The upstream end of the pipe 122 is connected to the downstream end of the secondary flow path 32 of the heat exchanger 30 (i.e., a connection structure provided on the pipe 32b). The downstream end of the pipe 122 is connected to the upstream end of a refrigerant flow path (hereinafter referred to as a radiator flow path) provided inside the radiator 110. The downstream end of the radiator flow path is connected to the upstream end of the pipe 124. The downstream end of the pipe 124 is connected to an intake port of the pump 150. The discharge port of the pump 150 is connected to the upstream end of the secondary flow path 32 of the heat exchanger 30 (i.e., a connection structure provided on the pipe 32a). A secondary refrigerant circulation path 140 is formed by the radiator flow path, the pipes 122 and 124, the pump 150, and the secondary flow path 32. The secondary refrigerant circulation path 140 is an annular path through which the refrigerant circulates. The conductivity of the refrigerant in the secondary refrigerant circulation path 140 is higher than the conductivity of the refrigerant in the primary refrigerant circulation path 40. The pump 150 pumps the refrigerant from the pipe 124 toward the secondary flow path 32. When the pump 150 operates, the refrigerant flows through the secondary flow path 32, the pipe 122, the radiator flow path, and the pipe 124 in this order. That is, the refrigerant circulates in the secondary refrigerant circulation path 140. In addition, when the refrigerant circulates in the secondary refrigerant circulation path 140, the refrigerant also flows in the bypass flow path 82, enabling the intercooler 80 to operate.

[0026] The fuel cell cooling system 100 has a reservoir tank 170. The reservoir tank 170 is connected to the secondary refrigerant circulation path 140 at positions upstream and downstream of the heat exchanger 30. The reservoir tank 170 stores an excess amount of refrigerant in the secondary refrigerant circulation path 140.

[0027] An air conditioning circuit 200 is connected to the pipe 122. The air conditioning circuit 200 has an air conditioning refrigerant circulation path 210, a pump 220, a water heater 230, a heater core 240, a valve 250, and the like. When the valve 250 is opened, a refrigerant flows between the secondary refrigerant circulation path 140 and the air conditioning refrigerant circulation path 210. The air conditioning circuit 200 adjusts the temperature in the passenger compartment of the electric vehicle by exchanging heat with the refrigerant in the air conditioning refrigerant circulation path 210.

[0028] When the electric vehicle is in use, the fuel cell cooling system 100 operates. When the fuel cell cooling system 100 operates, the pump 150 circulates the refrigerant in the secondary refrigerant circuit 140, and the pump 50 circulates the refrigerant in the primary refrigerant circuit 40. The radiator 110 cools the refrigerant circulating in the secondary refrigerant circuit 140. Therefore, the refrigerant cooled by the radiator 110 flows in the secondary flow path 32 of the heat exchanger 30. The heat exchanger 30 cools the refrigerant in the primary flow path 31 by heat exchange between the refrigerant in the secondary flow path 32 and the refrigerant in the primary flow path 31. Therefore, the refrigerant cooled by the heat exchanger 30 flows in the fuel cell flow path 22 of the fuel cell 20. This cools the fuel cell 20.

[0029] The conductivity of the refrigerant in the primary refrigerant circulation path 40 is lower than that of the refrigerant in the secondary refrigerant circulation path 140. In addition, the primary refrigerant circulation path 40 is provided with an ion exchanger 60 via a parallel flow path 62. As described above, when the refrigerant circulates in the primary refrigerant circulation path 40, the refrigerant also flows in the parallel flow path 62 at all times, and ions in the refrigerant are removed by the ion exchanger 60. Therefore, an increase in the conductivity of the refrigerant in the primary refrigerant circulation path 40 is suppressed. Therefore, high insulation is ensured between the fuel cell 20 and the heat exchanger 30 (i.e., the ground point). On the other hand, since the secondary refrigerant circulation path 140 is not provided with an ion exchanger, the conductivity of the refrigerant in the secondary refrigerant circulation path 140 is high. Therefore, the insulation resistance between the radiator 110 and the heat exchanger 30 is low. However, since the heat exchanger 30 and the fuel cell 20 are insulated from each other, the insulation between the radiator 110 and the fuel cell 20 is ensured.

[0030] By dividing the refrigerant circulation path into a primary refrigerant circulation path 40 and a secondary refrigerant circulation path 140 and making the conductivity of the refrigerant in the secondary refrigerant circulation path 140 higher than the conductivity of the refrigerant in the primary refrigerant circulation path 40, the following advantages are obtained.

[0031] The first advantage is that the ion concentration in the refrigerant in the primary refrigerant circulation path 40 is unlikely to increase. When the radiator and the fuel cell are connected by one refrigerant circulation path, the refrigerant circulation path becomes long. In contrast, when the primary refrigerant circulation path 40 and the secondary refrigerant circulation path 140 are provided independently, the primary refrigerant circulation path 40 and the secondary refrigerant circulation path 140 become short. By shortening the primary refrigerant circulation path 40, the amount of ions eluted from the components (i.e., piping, etc.) of the primary refrigerant circulation path 40 into the refrigerant is reduced. In general, the part that is likely to cause ions to elute into the refrigerant is the radiator. In the fuel cell cooling system 100, the radiator 110 is separated from the primary refrigerant circulation path 40, so that ions do not elute from the radiator 110 into the refrigerant in the primary refrigerant circulation path 40. Furthermore, in the fuel cell cooling system 100, the intercooler 80 and the air conditioning circuit 200 are also separated from the primary refrigerant circulation path 40, so there is no elution of ions from the intercooler 80 and the air conditioning circuit 200 into the refrigerant in the primary refrigerant circulation path 40. Therefore, the ion concentration is unlikely to increase in the refrigerant in the primary refrigerant circulation path 40. As a result, the amount of ions removed by the ion exchanger 60 is also reduced, allowing the ion exchanger 60 to be made smaller in size.

[0032] The second advantage is the reduction in parts costs. In the fuel cell cooling system 100, insulation is ensured between the fuel cell 20 and the heat exchanger 30, so there is no need to ensure insulation between the radiator 110 and the heat exchanger 30. Therefore, a refrigerant with high conductivity can be used as the refrigerant in the secondary refrigerant circulation path 140. In addition, since there is no need to manage the conductivity of the refrigerant in the secondary refrigerant circulation path 140, the material of the components (i.e., piping, etc.) of the secondary refrigerant circulation path 140 can be selected without considering the elution of ions. In this way, the range of choices for the refrigerant and components of the secondary refrigerant circulation path 140 is wider, so that inexpensive materials can be used.

[0033] The third advantage is reduced cleaning costs. When a refrigerant with low conductivity is used, the inside of the piping needs to be cleaned before the vehicle is shipped. This is to prevent ions from dissolving into the refrigerant. In the fuel cell cooling system 100, a refrigerant with low conductivity is used only in the primary refrigerant circulation path 40, so cleaning the inside of the secondary refrigerant circulation path 140 is not necessary. Since the primary refrigerant circulation path 40 is short and the radiator 110, intercooler 80, air conditioning circuit 200, etc. are not connected to the primary refrigerant circulation path 40, cleaning of the primary refrigerant circulation path 40 can be easily performed. Therefore, the cost required for cleaning before shipping can be reduced.

[0034] Next, the advantages of the fuel cell cooling unit 10 will be described. As described above, the fuel cell cooling system 100 is manufactured by adding the radiator 110, the pipes 122, 124, etc. to the fuel cell cooling unit 10 configured to be able to be distributed. That is, the fuel cell cooling unit 10 is designed by the manufacturer of the fuel cell cooling unit 10, and the secondary refrigerant circulation path 140 is designed by the user of the fuel cell cooling unit 10 (i.e., the manufacturer of the electric vehicle). Since insulation is ensured between the fuel cell 20 and the heat exchanger 30 in the fuel cell cooling unit 10, the manufacturer of the electric vehicle can design the secondary refrigerant circulation path 140 without considering insulation. Also, since the secondary flow path 32 of the heat exchanger 30 is separated from the primary refrigerant circulation path 40, the manufacturer of the electric vehicle can design the secondary refrigerant circulation path 140 without considering the influence of pressure from the secondary refrigerant circulation path 140 to the primary refrigerant circulation path 40. In this way, by using the fuel cell cooling unit 10, various designs of the secondary refrigerant circulation path 140 are possible. That is, by using the fuel cell cooling unit 10, the fuel cell can be used in various forms.

[0035] In the above-described embodiment, since the intercooler 80 is provided on the secondary refrigerant circulation path 140 side, coordinated control of the pump 50 and the pump 150 is required to control the cooling of the fuel cell 20 and the intercooler 80. For this reason, the intercooler 80 may be provided on the primary refrigerant circulation path 40 side, as shown in Fig. 3. With this configuration, the cooling of the fuel cell 20 and the intercooler 80 can be controlled by controlling only the pump 50.

[0036] In the above-described embodiment, a fuel cell cooling system mounted on an electric vehicle has been described, but the technology disclosed in this specification may also be applied to a fuel cell cooling system used for purposes other than electric vehicles.

[0037] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical utility. [Explanation of symbols]

[0038] 10: Fuel cell cooling unit 20:Fuel cell 30: Heat exchanger 31: Primary flow path 32: Secondary flow path 40: Primary refrigerant circulation path 60: Ion exchanger 80: Intercooler 110: Radiator 140:Secondary refrigerant circulation path

Claims

1. a primary refrigerant circulation path through which a refrigerant circulates; a fuel cell cooled by a refrigerant flowing through the primary refrigerant circulation path; a heat exchanger having a primary flow path and a secondary flow path, the primary flow path constituting a part of the primary refrigerant circulation path, and exchanging heat between the primary flow path and the secondary flow path; having A connection structure capable of attaching and detaching a pipe is provided at each of the upstream end and downstream end of the secondary flow path. Fuel cell cooling unit.

2. a parallel flow path connected in parallel to a fuel cell flow path, which is a portion of the primary coolant circulation path that passes through the fuel cell; an ion exchanger for removing ions from the refrigerant in the parallel flow paths; and When a coolant is circulating in the primary coolant circulation path, the coolant always flows in the fuel cell flow path and the parallel flow path. The fuel cell cooling unit according to claim 1 .

3. The cooling system further includes a pump for circulating the cooling medium in the primary cooling medium circulation path, The pump outlet is connected to an upstream end of the primary flow path by a flange connection.

3. The fuel cell cooling unit according to claim 1 or 2.

4. a bypass flow passage connecting an upstream portion and a downstream portion of the secondary flow passage with respect to the heat exchanger; an intercooler provided in the bypass flow path for cooling air supplied to the fuel cell; The fuel cell cooling unit according to claim 1 or 2, further comprising:

5. a primary refrigerant circulation path through which a refrigerant circulates; a fuel cell cooled by a refrigerant flowing through the primary refrigerant circulation path; a secondary refrigerant circulation path through which the refrigerant circulates; a radiator that cools the refrigerant flowing through the secondary refrigerant circulation path; a heat exchanger having a primary flow path and a secondary flow path, the primary flow path constituting a part of the primary refrigerant circulation path, the secondary flow path constituting a part of the secondary refrigerant circulation path, and exchanging heat between the primary flow path and the secondary flow path; having the conductivity of the refrigerant in the secondary refrigerant circuit is higher than the conductivity of the refrigerant in the primary refrigerant circuit; Fuel cell cooling system.

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