Fuel cell vehicle and hydrogen engine vehicle

Abstract

To provide a fuel cell vehicle which can inhibit temperature change of a hydrogen tank and prevent deterioration of the hydrogen tank.SOLUTION: A fuel cell system 1 mounted on a fuel cell vehicle 100 includes: an FC stack 2; a hydrogen tank 3 which is filled with hydrogen to be supplied to the FC stack 2; and a conduit tube 11 which is provided between the FC stack 2 and the hydrogen tank 3 to circulate a refrigerant.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to fuel cell vehicles and hydrogen engine vehicles. [Background technology]

[0002] Hydrogen tanks that store hydrogen at high pressure for supply to fuel cell stacks, and hydrogen tanks that are charged with hydrogen to supply to hydrogen engines, tend to experience a drop in temperature when hydrogen is consumed rapidly, and a rise in temperature when hydrogen is rapidly refilled. Some hydrogen tanks have a reduced lifespan if they are operated outside their operating temperature range. For this reason, it is desirable to provide a device to adjust the temperature of the hydrogen tank.

[0003] Patent document 1 describes a fuel cell system equipped with a secondary battery that stores electricity to supplement the electricity generated by the fuel cell stack, in which the secondary battery is installed in contact with the outer surface of the body of the hydrogen tank, thereby allowing heat exchange between the secondary battery and the hydrogen tank and adjusting their temperatures. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-129342 Summary of the Invention [Problem to be solved by the invention]

[0005] However, secondary batteries tend to generate heat and rise in temperature during charging and discharging, so it is generally desirable to cool them. Conventional methods such as those described in Patent Document 1 utilize heat exchange between the secondary battery and the hydrogen tank. However, when a fuel cell system is applied to a fuel cell vehicle, the hydrogen in the tank is consumed during high-speed driving (high power output), causing the temperature of the hydrogen tank to drop, which is advantageous as it also has a cooling effect on the secondary battery. On the other hand, when hydrogen is filled into the hydrogen tank while the vehicle is stopped, the temperature of the hydrogen tank rises, which may not be advantageous for the secondary battery. As such, conventional methods that utilize heat exchange between the secondary battery and the hydrogen tank leave room for improvement in terms of suppressing temperature changes in the hydrogen tank.

[0006] An object of the present disclosure is to provide a fuel cell vehicle and a hydrogen engine vehicle that can suppress temperature changes in a hydrogen tank and prevent deterioration of the hydrogen tank. [Means for solving the problem]

[0007] A fuel cell vehicle according to one aspect of an embodiment of the present invention comprises an FC stack, a hydrogen tank filled with hydrogen to be supplied to the FC stack, and a conduit arranged between the FC stack and the hydrogen tank for circulating a coolant. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a fuel cell vehicle and a hydrogen engine vehicle that can suppress temperature changes in the hydrogen tank and prevent deterioration of the hydrogen tank. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a conventional fuel cell system according to a reference embodiment. [Figure 2] FIG. 1 is a diagram showing a schematic configuration of a fuel cell system according to a first embodiment; [Figure 3] FIG. 10 is a diagram showing a schematic configuration of a fuel cell system according to a second embodiment. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a hydrogen engine system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0011] [Reference form] 1 is a diagram showing a schematic configuration of a conventional fuel cell system 10 according to a reference embodiment. The fuel cell system 10 includes a fuel cell (FC) stack 2, a hydrogen tank 3, and a cooling system 4.

[0012] FC stack 2 generates electricity by outputting the electricity generated in the process of converting hydrogen and oxygen into water. FC stack 2 is made up of multiple layers of cells stacked together as a single package, each with a structure in which a solid polymer membrane (electrolyte membrane) is sandwiched between positive and negative electrode plates. The positive electrode (oxygen electrode) and negative electrode (hydrogen electrode) of each cell have many thin grooves, and oxygen and hydrogen supplied from the outside pass through these grooves, sandwiching the electrolyte membrane, causing a reaction and generating electricity.

[0013] The hydrogen tank 3 compresses and stores the hydrogen that is supplied to the negative electrode of each cell of the FC stack 2. The hydrogen tank 3 is connected to the FC stack 2 via a hydrogen supply system 5. The hydrogen supplied from the hydrogen tank 3 is depressurized by the hydrogen supply system 5 before being sent to the negative electrode of each cell of the FC stack 2. Note that although the example in Figure 1 illustrates a configuration in which the fuel cell system 10 is equipped with two hydrogen tanks 3, the number of hydrogen tanks 3 may be any number other than two.

[0014] The cooling system 4 cools the FC stack 2. The cooling system 4 has a cooling water flow path 6 that circulates cooling water (refrigerant). The cooling system 4 has a pump 7 installed on the cooling water flow path 6, and by driving the pump 7, the cooling water is circulated within the cooling water flow path 6. The FC stack 2 is placed within the cooling water flow path 6, and is cooled by exchanging heat with the cooling water circulating within the cooling water flow path 6.

[0015] The cooling system 4 also has a radiator 8 installed on the cooling water flow path 6. The cooling water that has absorbed heat through heat exchange with the FC stack 2 is re-cooled in the radiator 8 and reused for heat exchange with the FC stack 2 via the cooling water flow path 6. When the FC stack 2 is operating at high output, air enters the radiator 8 and cooling can be carried out, but if the cooling cannot keep up, the output of the FC stack 2 can be limited or other measures can be taken.

[0016] In the example of Fig. 1, the cooling system 4 circulates the coolant in the coolant flow path 6 in the direction of flow from the FC stack 2 → pump 7 → radiator 8 in that order, or from the FC stack 2 → radiator 8 → pump 7 in that order. Note that in Fig. 1 and Figs. 2 and 3, which will be described later, the coolant, which is an example of a refrigerant, circulating in pipes such as the coolant flow path 6, is shown hatched with thick lines.

[0017] [First embodiment] 2 is a diagram showing a schematic configuration of a fuel cell system 1 according to the first embodiment. The fuel cell system 1 according to the first embodiment is mounted on a fuel cell vehicle 100 according to the embodiment, and is used to supply power to a drive motor that is a drive source for the vehicle.

[0018] As shown in Fig. 2, the fuel cell system 1 of the first embodiment includes a conduit 11 in addition to the components of the conventional fuel cell system 1 described with reference to Fig. 1. The conduit 11 is provided between the FC stack 2 and the hydrogen tank 3, and circulates coolant. More specifically, the conduit 11 is connected to the coolant flow path 6 of the cooling system 4, and is configured to circulate at least a portion of the coolant circulating within the coolant flow path 6. In the example of Fig. 2, one end of the conduit 11 is connected to the coolant flow path 6 at a position where the FC stack 2 is housed, and the other end of the conduit 11 is connected to the coolant flow path 6 at a position between the pump 7 and the radiator 8.

[0019] A second pump 12 is installed on the conduit 11, and by driving the second pump 12, the cooling water is circulated within the conduit 11. The hydrogen tank 3 is disposed within the conduit 11, and is cooled or heated by heat exchange with the cooling water circulating within the conduit 11.

[0020] In a configuration in which the fuel cell system 1 of the first embodiment is applied to a fuel cell vehicle, when the vehicle is traveling at high speed, that is, when the FC stack 2 is generating high output, a large amount of hydrogen is supplied to the FC stack 2 from the hydrogen tank 3. As a result, the hydrogen stored in the hydrogen tank 3 is rapidly consumed, causing the temperature of the hydrogen tank 3 to drop rapidly. In this case, the second pump 12 is driven to introduce the cooling water circulating in the cooling water flow path 6 into the conduit 11. As a result, the cooling water flowing in the conduit 11 exchanges heat with the hydrogen tank 3, whose temperature has dropped, to be cooled, and then returned to the cooling water flow path 6.

[0021] At this time, because the FC stack 2 is in a high-output state, the amount of heat generated by the FC stack 2 increases, and the cooling water circulating in the cooling water flow path 6 is usually heated to over 60°C, which may result in a situation where the cooling system 4 alone is unable to sufficiently cool the FC stack 2. To avoid this situation, it is desirable to be able to cool the cooling water by some means. In contrast, in this embodiment, as described above, the cooling water that has been heated and used to cool the FC stack 2 is cooled again by passing around the hydrogen tank 3. This ensures the cooling effect of the FC stack 2 even in situations where the cooling system 4 alone is unable to sufficiently cool the FC stack 2. Furthermore, in this case, the heat exchange between the cooling water and the hydrogen tank 3 can mitigate the temperature drop in the hydrogen tank 3.

[0022] On the other hand, when filling the hydrogen tank 3 with hydrogen while the vehicle is stopped, the amount of hydrogen in the hydrogen tank 3 increases rapidly, causing a sudden rise in temperature in the hydrogen tank 3. Furthermore, because the vehicle is stopped, the FC stack 2 is also stopped or at low output, so heat generation in the FC stack 2 is suppressed and cooling by the cooling system 4 is less necessary than when the vehicle is running. In this case, the second pump 12 is driven to introduce the cooling water circulating in the cooling water flow path 6 into the conduit 11. As a result, the cooling water flowing in the conduit 11 exchanges heat with the hydrogen tank 3, which has a rising temperature, to cool the hydrogen tank 3, before being returned to the cooling water flow path 6. As a result, the heat exchange between the cooling water and the hydrogen tank 3 can mitigate the temperature rise in the hydrogen tank 3.

[0023] As described above, the fuel cell system 1 mounted on the fuel cell vehicle 100 according to the first embodiment comprises the FC stack 2, the hydrogen tank 3 filled with hydrogen to be supplied to the FC stack 2, and a conduit 11 provided between the FC stack 2 and the hydrogen tank 3 for circulating cooling water as an example of a refrigerant. With this configuration, heat from the FC stack 2, which tends to become hot mainly during power generation, is transferred to the hydrogen tank 3 by the cooling water passing through the conduit 11, thereby preventing a sudden drop in temperature when hydrogen is released from the hydrogen tank 3. Furthermore, the hydrogen tank 3 can also be cooled by the cooling water passing through the conduit 11 when filling it with hydrogen, thereby preventing a sudden rise in temperature of the hydrogen tank 3. This prevents temperature changes in the hydrogen tank 3 and prevents deterioration of the hydrogen tank 3.

[0024] Furthermore, in the fuel cell system 1 of the first embodiment, when necessary, specifically in situations where a sudden rise or fall in temperature of the hydrogen tank 3 may occur, the second pump 12 is driven to introduce cooling water into the conduit 11, thereby suppressing a sudden rise or fall in temperature of the hydrogen tank 3. This allows cooling water to circulate to the hydrogen tank 3 side only when necessary, improving the cooling efficiency of the cooling system 4 and suppressing power consumption by the second pump 12.

[0025] High-pressure gas tanks are typically made of metal, and their temperature rarely rises or falls beyond their operating temperature range. However, if a material such as resin is used, durability problems arise at relatively high or low temperatures. Temperature changes also affect the rate at which the amount of high-pressure gas, such as hydrogen gas, changes in its fill volume or consumption. For this reason, when high-pressure gas tanks are made of materials other than metal, such as resin, it is advisable to heat the low-temperature side and cool the high-temperature side in some way to prevent the tank temperature from deviating from the operating temperature range.

[0026] To address this issue, the fuel cell system 1 of this embodiment is configured so that the FC stack 2 and the hydrogen tank 3 are both placed within the conduit 11, and heat exchange with the FC stack 2 and the hydrogen tank 3 is carried out using common cooling water circulating within the conduit 11, thereby suppressing sudden temperature changes in the hydrogen tank 3.

[0027] Therefore, when using a hydrogen tank 3 made of resin, which is vulnerable to sudden temperature changes, the fuel cell system 1 of this embodiment is particularly effective in preventing deterioration such as cracking of the hydrogen tank 3. Furthermore, the use of a hydrogen tank 3 made of resin allows the system to be lighter than a system made of metal, expanding the range of application and improving versatility.

[0028] [Second embodiment] 3 is a diagram showing a schematic configuration of a fuel cell system 1A according to the second embodiment. The fuel cell system 1A according to the second embodiment is mounted on a fuel cell vehicle 100 according to the embodiment and is used to supply power to a drive motor, which is a drive source for the vehicle.

[0029] As shown in Fig. 3, the fuel cell system 1A of the second embodiment includes a heat exchange system 13 instead of the cooling system 4 in the configuration of the conventional fuel cell system 1 described with reference to Fig. 1. The heat exchange system 13 cools the FC stack 2 with cooling water and exchanges heat with the hydrogen tank 3.

[0030] The heat exchange system 13 has a conduit 14 through which cooling water (refrigerant) circulates. A pump 7 and a radiator 8, similar to those in the fuel cell system 1, are installed on the conduit 14. The FC stack 2 and the hydrogen tank 3 are both placed inside the conduit 14, and exchange heat with the cooling water circulating inside the conduit 14.

[0031] In the example of Figure 3, heat exchange system 13 circulates cooling water within conduit 14 in the following order: FC stack 2 → hydrogen tank 3 → pump 7 → radiator 8, or in the following order: FC stack 2 → radiator 8 → pump 7 → hydrogen tank 3. In the example of Figure 3, a single pump 7 supplies cooling water to both the FC stack 2 and the hydrogen tank 3, so the performance of pump 7, such as the discharge rate, needs to be improved.

[0032] In the fuel cell system 1A of the second embodiment, by driving the pump 7 of the heat exchange system 13 to circulate cooling water within the conduit 14, it is possible to cool the FC stack 2 while suppressing sudden temperature increases and decreases in the hydrogen tank 3. This makes it possible to suppress temperature changes in the hydrogen tank 3 and prevent deterioration of the hydrogen tank 3.

[0033] [Third embodiment] The cooling water may be circulated as in the fuel cell systems 1 and 1A of the first and second embodiments, but in the case of an engine, since the exhaust often absorbs heat, the exhaust may be configured to warm the hydrogen tank 3 rather than cooling it.

[0034] 4 is a diagram showing a schematic configuration of a hydrogen engine system 1B according to the third embodiment. The hydrogen engine system 1B according to the third embodiment is mounted on a hydrogen engine vehicle 200 according to the embodiment.

[0035] The hydrogen engine system 1B includes a hydrogen tank 3, a hydrogen engine 15 (vehicle drive source), and an exhaust pipe 16. The hydrogen engine 15 is an engine in which the fuel of a conventional internal combustion engine is replaced with hydrogen, and is able to obtain power by utilizing the hydrogen combustion reaction. A tank housing section 17 that houses the hydrogen tank 3 is provided midway along the exhaust pipe 16. In the third embodiment, the exhaust pipe 16 and the tank housing section 17 function as a heating section that warms the hydrogen tank 3 by utilizing the heat generated when the hydrogen engine 15 is operating.

[0036] If sound-absorbing material is placed inside the tank housing 17 to provide a sound-absorbing function, the muffler used in a general engine can be used, reducing the number of parts. Unlike a gasoline engine, there is no burnt residue in the exhaust gas, and only water is produced, so there is no impact on deterioration of the hydrogen tank.

[0037] The hydrogen engine system 1B mounted on a hydrogen engine vehicle 200 according to the third embodiment comprises a hydrogen engine 15, a hydrogen tank 3 filled with hydrogen to be supplied to the hydrogen engine 15, and an exhaust pipe 16 and tank housing 17 that serve as a heating unit that uses heat generated when the hydrogen engine 15 is operating to heat the hydrogen tank 3. With this configuration, when the temperature of the hydrogen tank 3 drops as hydrogen stored in the hydrogen tank 3 is supplied to the hydrogen engine 15 while the vehicle is running, the heat generated when the hydrogen engine 15 is operating can be used to warm the hydrogen tank 3, thereby mitigating the temperature drop in the hydrogen tank 3. This makes it possible to suppress temperature changes in the hydrogen tank 3 and prevent deterioration of the hydrogen tank 3.

[0038] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0039] 100 Fuel Cell Vehicles 200 Hydrogen Engine Vehicles 1. 1A fuel cell system 1B Hydrogen Engine System 2 FC stack 3 Hydrogen Tank 11, 14 Conduit 15 Hydrogen engine 16 Exhaust pipe (heating section) 17 Tank housing section (heating section)

Claims

1. FC stack and a hydrogen tank filled with hydrogen to be supplied to the FC stack; a conduit for circulating a refrigerant, the conduit being provided between the FC stack and the hydrogen tank; A fuel cell vehicle equipped with:

2. A hydrogen engine, a hydrogen tank filled with hydrogen to be supplied to the hydrogen engine; a heating unit that heats the hydrogen tank 3 by utilizing heat generated when the hydrogen engine is operating; A hydrogen engine vehicle equipped with:

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