Heat exchanger

Abstract

The invention provides a heat exchanger which can restrain useless upsizing of the heat exchanger. The heat exchanger may be provided with: a first flow path; a second flow path that is adjacent to the first flow path and exchanges heat with the first flow path; a third flow path that is adjacent to the second flow path and exchanges heat with the second flow path; and a fourth flow path that is adjacent to the third flow path and exchanges heat with the third flow path. The first flow path and the third flow path are respectively connected with one of a flow path for fuel gas supplied to the fuel cell and a flow path for cooling water supplied to the fuel cell. Each of the second flow path and the fourth flow path is connected to one of a flow path for fuel exhaust gas discharged from the fuel cell, a flow path for oxidant gas supplied to the fuel cell, a flow path for oxidant exhaust gas discharged from the fuel cell, and a flow path for cooling water discharged from the fuel cell.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a heat exchanger for a fuel cell. Background Art

[0002] In Patent Document 1, a heat exchanger for a fuel cell is described. The heat exchanger includes: a first flow path that is a flow path through which a fluid having a relatively low temperature flows; and second, third, and fourth flow paths that are flow paths through which fluids having relatively high temperatures flow. The second flow path is adjacent to the first flow path, and heat exchange occurs between the first flow path and the second flow path. The third flow path is adjacent to the first flow path, and heat exchange occurs between the first flow path and the third flow path. The fourth flow path is adjacent to the first flow path, and heat exchange occurs between the first flow path and the fourth flow path.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2008-204834

[0004] In the above heat exchanger, the three flow paths are arranged asymmetrically so as to exchange heat with respect to one flow path. Therefore, the heat exchanger as a whole is relatively likely to be enlarged. In this specification, a technology for suppressing the unnecessary enlargement of the heat exchanger is provided. Summary of the Invention

[0005] The technology disclosed in this specification is embodied as a heat exchanger for a fuel cell. In a first aspect of this technology, the heat exchanger may also include: a first flow path; a second flow path that is adjacent to the first flow path and exchanges heat with the first flow path; a third flow path that is adjacent to the second flow path and exchanges heat with the second flow path; and a fourth flow path that is adjacent to the third flow path and exchanges heat with the third flow path. It may be configured such that either a flow path for fuel gas supplied to the fuel cell or a flow path for cooling water supplied to the fuel cell is connected to the first flow path and the third flow path respectively, and either a flow path for fuel exhaust gas discharged from the fuel cell, a flow path for oxidant gas supplied to the fuel cell, a flow path for oxidant exhaust gas discharged from the fuel cell, or a flow path for the cooling water discharged from the fuel cell is connected to the second flow path and the fourth flow path respectively.

[0006] In the above heat exchanger, either a fuel gas flow path supplied to the fuel cell or a cooling water flow path supplied to the fuel cell is connected to the first flow path and the third flow path, respectively. On the other hand, either a fuel exhaust gas flow path discharged from the fuel cell, an oxidant gas flow path supplied to the fuel cell, an oxidant exhaust gas flow path discharged from the fuel cell, or a cooling water flow path discharged from the fuel cell is connected to the second flow path and the fourth flow path, respectively. That is, it is configured such that a relatively low-temperature fluid flows through the first flow path and the third flow path, respectively, and a relatively high-temperature fluid flows through the second flow path and the fourth flow path, respectively. Based on this structure, the flow paths for the low-temperature fluid and the high-temperature fluid are alternately arranged, and efficient heat exchange can be performed between adjacent pairs of flow paths. Therefore, it is possible to suppress the unnecessary enlargement of the heat exchanger.

[0007] In the second aspect of the present technology, it may also be that, on the basis of the first aspect above, the first flow path is also adjacent to the fourth flow path and heat exchange also occurs between them. Based on this structure, for all of the first to fourth flow paths, they can be adjacent to two other flow paths. By further improving the efficiency of heat exchange, further miniaturization of the heat exchanger can be achieved.

[0008] In the third aspect of the present technology, it may also be that, on the basis of the first or second aspect above, the second flow path and the third flow path are surrounded by at least one of the first flow path and the fourth flow path. Based on this structure, it is possible to increase the area where the first flow path is adjacent to the second flow path and / or the area where the fourth flow path is adjacent to the third flow path, and the efficiency of heat exchange can be improved. In addition, it is possible to suppress unnecessary heat exchange between the second flow path and the third flow path and the outside.

[0009] In the fourth aspect of the present technology, it may also be that, on the basis of the third aspect above, the first flow path, the second flow path, the third flow path, and the fourth flow path are arranged in a concentric circle manner. Based on this structure, for all of the first to fourth flow paths, it is possible to increase the area adjacent to other flow paths, and the efficiency of heat exchange can be improved. In addition, except for the outermost flow path, it is possible to suppress unnecessary heat exchange between each flow path and the outside.

[0010] In the fifth aspect of the present technology, it may also be: based on any one of the above first to fourth aspects, a flow path for the fuel gas is connected to the above first flow path. Moreover, a flow path for the discharged cooling water may be connected to the above second flow path. Moreover, a flow path for the supplied cooling water may be connected to the above third flow path. Moreover, a flow path for the oxidant gas may be connected to the above fourth flow path. With this structure, in the arrangement of the four flow paths in the heat exchanger, the two flow paths through which the cooling water flows are arranged in the central part of the arrangement. Compared with the fuel gas and its exhaust gas as gases, the cooling water as a liquid has a higher heat exchange capacity. Therefore, if the two flow paths through which the cooling water flows are arranged in the center in the arrangement of the four flow paths, the efficiency of heat exchange can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 FIG. is a diagram showing the structure of a fuel system.

[0012] Figure 2 Showing Figure 1 A cross-sectional view of the heat exchanger of Embodiment 1 taken along line II-II.

[0013] Figure 3 (A) in... shows a cross-sectional view of the heat exchanger of Embodiment 2, Figure 3 and (B) in... shows a cross-sectional view of the heat exchanger of Embodiment 3.

[0014] Figure 4 (A) in... shows a cross-sectional view of the heat exchanger of Embodiment 4, Figure 4 and (B) in... shows a cross-sectional view of the heat exchanger of Embodiment 5.

[0015] Figure 5 Showing a cross-sectional view of the heat exchanger of Embodiment 6.

[0016] Figure 6 FIG. is a diagram showing the structure of the heat exchanger of Embodiment 7.

[0017] Description of Reference Numerals:

[0018] 10, 110, 210, 310, 410, 510, 610... heat exchangers; 12... fuel cell; 20... fuel gas flow path; 22... fuel exhaust gas flow path; 24... oxidant gas flow path; 26... oxidant exhaust gas flow path; 28... first cooling water flow path; 30... second cooling water flow path; 32, 332... first flow path; 34, 334, 434, 634... second flow path; 36... third flow path; 38, 438, 638... fourth flow path; C... central axis. DETAILED DESCRIPTION OF THE INVENTION

[0019]

Embodiment

[0020] (Example 1)

[0021] Refer to Figure 1 、 Figure 2 to describe the heat exchanger 10 of Example 1. As Figure 1 shown, the heat exchanger 10 is used in the fuel cell system 100. As an example, the fuel cell system 100 is mounted on an electric vehicle. The fuel cell system 100 supplies the generated electric power to the driving motor of the electric vehicle. Alternatively, the fuel cell system 100 charges the battery of the electric vehicle with the generated electric power. However, the heat exchanger 10 in the present technology is not limited to being mounted on an electric vehicle, and may also be mounted on other mobile devices equipped with fuel cells.

[0022] In addition to the heat exchanger 10, the fuel cell system 100 further includes a fuel cell 12, a fuel gas supply unit 14, an oxidant gas supply unit 16, a radiator 18, and a plurality of flow paths 20, 22, 24, 26, 28, 30.

[0023] A fuel gas and an oxidant gas are supplied to the fuel cell 12. In the present embodiment, the fuel gas is hydrogen, and the oxidant gas is air (oxygen). The fuel cell 12 includes a plurality of fuel cell monomers (not shown). In each of the plurality of fuel cell monomers (hereinafter simply referred to as single cells), the supplied fuel gas reacts with the oxidant gas to generate electricity.

[0024] A plurality of flow paths 20, 22, 24, 26, 28, 30 are respectively connected to the fuel cell 12. For the plurality of flow paths 20, 22, 24, 26, 28, 30, it includes a fuel gas flow path 20, a fuel exhaust gas flow path 22, an oxidant gas flow path 24, an oxidant exhaust gas flow path 26, a first cooling water flow path 28, and a second cooling water flow path 30. The fuel gas flow path 20 is a flow path for the fuel gas supplied to the fuel cell 12. The fuel exhaust gas flow path 22 is a flow path for the fuel exhaust gas discharged from the fuel cell 12. The oxidant gas flow path 24 is a flow path for the oxidant gas supplied to the fuel cell 12. The oxidant exhaust gas flow path 26 is a flow path for the oxidant exhaust gas discharged from the fuel cell 12. The first cooling water flow path 28 is a flow path for the cooling water supplied to the fuel cell 12. The second cooling water flow path 30 is a flow path for the cooling water discharged from the fuel cell 12.

[0025] The fuel gas that passes through each single cell is discharged from the fuel cell 12 as fuel exhaust gas through the fuel exhaust gas flow path 22. The oxidant gas that passes through each single cell is discharged from the fuel cell 12 as oxidant exhaust gas through the oxidant exhaust gas flow path 26. In the fuel exhaust gas flow path 22 and the oxidant exhaust gas flow path 26, there flow fuel exhaust gas and oxidant exhaust gas that are heated due to the fuel cell reaction and have a relatively high temperature compared to the fluids in other flow paths of the fuel cell system 100.

[0026] Although not particularly limited, the fuel exhaust gas flow path 22 may also be connected to a gas-liquid separator (not shown), and impurities such as water generated by the reaction in each single cell can also be removed by the gas-liquid separator. Moreover, the fuel exhaust gas discharged from the fuel cell 12 may be returned to the fuel gas flow path 20 via the gas-liquid separator.

[0027] The fuel gas supply unit 14 has a fuel gas tank for storing the fuel gas. The fuel gas supply unit 14 is connected to the fuel cell 12 via the fuel gas flow path 20. The fuel gas supply unit 14 supplies the fuel gas stored in the fuel gas tank to the fuel cell 12. In the fuel gas flow path 20, there flows fuel gas with a relatively low temperature.

[0028] The oxidant gas supply unit 16 has a compressor for sending out the oxidant gas. The oxidant gas supply unit 16 is connected to the fuel cell 12 via the oxidant gas flow path 24. The oxidant gas supply unit 16 compresses external air by the compressor and supplies the air as an oxidant to the fuel cell 12. In the oxidant gas flow path 24, there flows oxidant gas with a relatively high temperature due to the compression by the compressor.

[0029] The radiator 18 is a heat exchanger that exchanges heat between external air and cooling water. The radiator 18 is connected to the first cooling water flow path 28. Therefore, the radiator 18 is connected to the fuel cell 12 via the first cooling water flow path 28. Thus, in the first cooling water flow path 28, the cooling water supplied from the radiator 18 flows toward the fuel cell 12. In the first cooling water flow path 28, there flows cooling water with a relatively low temperature that has been cooled by the radiator 18. The radiator 18 is connected to the second cooling water flow path 30. Therefore, the radiator 18 is connected to the fuel cell 12 via the second cooling water flow path 30. Thus, in the second cooling water flow path 30, the cooling water discharged from the fuel cell 12 flows toward the radiator 18. Therefore, in the second cooling water flow path 30, there flows cooling water with a relatively high temperature that has been heated by the fuel cell 12. In addition, a pump (not shown) for circulating the cooling water between them is provided between the radiator 18 and the fuel cell 12.

[0030] As Figure 1 and Figure 2As shown, the heat exchanger 10 includes a plurality of flow paths 32, 34, 36, 38, which have a first end 10a and a second end 10b and extend between the first end 10a and the second end 10b. The plurality of flow paths 32, 34, 36, 38 extend parallel to each other. The plurality of flow paths 32, 34, 36, 38 include a first flow path 32, a second flow path 34, a third flow path 36, and a fourth flow path 38. The second flow path 34 is adjacent to the first flow path 32 and exchanges heat with the first flow path 32. The third flow path 36 is adjacent to the second flow path 34 and exchanges heat with the second flow path 34. The fourth flow path 38 is adjacent to the third flow path 36 and exchanges heat with the third flow path 36. The plurality of flow paths 32, 34, 36, 38 are arranged in a row in the order of the first flow path 32, the second flow path 34, the third flow path 36, and the fourth flow path 38.

[0031] A fuel gas flow path 20 is connected to the first flow path 32. Specifically, the fuel gas flow path 20 is divided into an upstream portion and a downstream portion by the first flow path 32. More specifically, the downstream end of the upstream portion of the fuel gas flow path 20 is connected to the first flow path 32 at the first end 10a of the heat exchanger 10. The upstream end of the downstream portion of the fuel gas flow path 20 is connected to the first flow path 32 at the second end 10b of the heat exchanger 10. That is, in the heat exchanger 10, the fluid flows from the first end 10a toward the second end 10b in the first flow path 32 (in the Figure 2 depth direction of the paper surface).

[0032] An oxidant gas flow path 24 is connected to the second flow path 34. Specifically, the oxidant gas flow path 24 is divided into an upstream portion and a downstream portion by the second flow path 34. More specifically, the downstream end of the upstream portion of the oxidant gas flow path 24 is connected to the second flow path 34 at the second end 10b of the heat exchanger 10. The upstream end of the downstream portion of the oxidant gas flow path 24 is connected to the second flow path 34 at the first end 10a of the heat exchanger 10. That is, in the heat exchanger 10, the fluid flows from the second end 10b toward the first end 10a in the second flow path 34 (in the Figure 2 front direction of the paper surface).

[0033] A first cooling water flow path 28 is connected to the third flow path 36. Specifically, the first cooling water flow path 28 is divided into an upstream portion and a downstream portion by the third flow path 36. More specifically, the downstream end of the upstream portion of the first cooling water flow path 28 is connected to the third flow path 36 at the first end 10a of the heat exchanger 10. The upstream end of the downstream portion of the first cooling water flow path 28 is connected to the third flow path 36 at the second end 10b of the heat exchanger 10. That is, in the heat exchanger 10, the fluid flows from the first end 10a toward the second end 10b in the third flow path 36 (in the Figure 2 depth direction of the paper surface).

[0034] The second cooling water flow path 30 is connected to the fourth flow path 38. Specifically, the second cooling water flow path 30 is divided into an upstream portion and a downstream portion by the fourth flow path 38. More specifically, the downstream end of the upstream portion of the second cooling water flow path 30 is connected to the fourth flow path 38 at the second end 10b of the heat exchanger 10. The upstream end of the downstream portion of the second cooling water flow path 30 is connected to the fourth flow path 38 at the first end 10a of the heat exchanger 10. That is, in the heat exchanger 10, the fluid flows in the fourth flow path 38 from the second end 10b toward the first end 10a (toward Figure 2 the direction near the front of the paper surface).

[0035] The heat exchanger 10 includes a housing 40. The housing 40 is a cylindrical member. The housing 40 has a cylindrical peripheral wall 42 and a plurality of plate-like partition walls 44 located inside the peripheral wall 42. The peripheral wall 42 and the plurality of partition walls 44 extend between the first end 10a and the second end 10b in the heat exchanger 10. The plurality of partition walls 44 divide the first flow path 32, the second flow path 34, the third flow path 36, and the fourth flow path 38 inside the peripheral wall 42. The cross section of the peripheral wall 42 is substantially rectangular and has a first wall 42a, a second wall 42b, a third wall 42c, and a fourth wall 42d. Here, the cross section refers to the cross section of the peripheral wall 42 perpendicular to the direction of cylindrical extension. However, in other embodiments, the cross section of the peripheral wall 42 may be polygonal or circular. The first wall 42a and the third wall 42c are opposed to each other, and the second wall 42b and the fourth wall 42d are opposed to each other. The second wall 42b and the fourth wall 42d extend between the first wall 42a and the third wall 42c.

[0036] The plurality of partition walls 44 extend between the first end 10a and the second end 10b of the heat exchanger 10. The plurality of partition walls 44 extend between the first wall 42a and the third wall 42c. The plurality of partition walls 44 are juxtaposed at a predetermined interval inside the peripheral wall 42. The plurality of partition walls 44 each have a plurality of heat dissipation fins 44f. The plurality of heat dissipation fins 44f project from both side surfaces of the plurality of partition walls 44 located on the adjacent two flow path sides. Thereby, the contact area between both the first flow path 32 and the second flow path 34 and the partition walls 44 increases, and the heat exchange efficiency can be improved. The shape of each of the plurality of heat dissipation fins 44f is not particularly limited. The plurality of heat dissipation fins 44f may each be in the shape of a long strip plate or in the shape of a pin.

[0037] In the heat exchanger 10 in this embodiment, a fuel gas flow path 20 for supplying fuel gas to the fuel cell 12 is connected to the first flow path 32, and a first cooling water flow path 28 for supplying cooling water to the fuel cell 12 is connected to the third flow path 36. On the other hand, an oxidant gas flow path 24 for supplying oxidant gas to the fuel cell 12 is connected to the second flow path 34, and a second cooling water flow path 30 for discharging cooling water from the fuel cell 12 is connected to the fourth flow path. That is, it is configured such that in the first flow path 32 and the third flow path 36, relatively low-temperature fluids flow respectively, and in the second flow path 34 and the fourth flow path 38, relatively high-temperature fluids flow respectively. Based on this structure, the flow paths 32, 36 through which the low-temperature fluids flow and the flow paths 34, 38 through which the high-temperature fluids flow are alternately arranged, and efficient heat exchange can be performed between adjacent two flow paths. Therefore, the useless enlargement of the heat exchanger 10 can be suppressed.

[0038] In particular, in this embodiment, the multiple flow paths 32, 34, 36, 38 of the heat exchanger 10 are arranged such that the flow directions of the respective fluids are opposite to each other between adjacent two flow paths. That is, in the first flow path 32 and the second flow path 34, the flow directions of the respective fluids are opposite to each other, in the second flow path 34 and the third flow path 36, the flow directions of the respective fluids are opposite to each other, and in the third flow path 36 and the fourth flow path 38, the flow directions of the respective fluids are opposite to each other. Based on this structure, efficient heat exchange can be performed between adjacent two flow paths throughout the entire first end 10a to the second end 10b of the heat exchanger 10. However, in other embodiments, the flow directions of the respective fluids may also be the same between adjacent two flow paths.

[0039] Moreover, in this embodiment, fuel gas flows in the first flow path 32, and oxidant gas flows in the second flow path 34. On the other hand, cooling water flows in the third flow path 36 and the fourth flow path 38. That is, the respective fluids flowing in two adjacent flow paths among the multiple flow paths 32, 34, 36, 38 of the heat exchanger 10 are either both gases or both water. Based on this structure, efficient heat exchange can be performed between adjacent two flow paths. However, in other embodiments, between adjacent two flow paths, it may also be that the fluid flowing in one flow path is a gas and the fluid flowing in the other flow path is water.

[0040] (Embodiment 2)

[0041] Refer to Figure 3 in (A) to describe the heat exchanger 110 of Embodiment 2. As Figure 3As shown in (A) of FIG. 0, the heat exchanger 110 of Embodiment 2 includes eight flow paths formed by arranging the same multiple flow paths 32, 34, 36, and 38 as those of Embodiment 1 in a single row and repeating the arrangement. In this regard, it is different from the heat exchanger 10 of Embodiment 1. For other structures of the heat exchanger 110 of Embodiment 2, they can be configured in the same manner as those of Embodiment 1. By configuring in this way, the flow paths 32 and 36 through which the low-temperature fluid flows and the flow paths 34 and 38 through which the high-temperature fluid flows are also alternately arranged, enabling efficient heat exchange between adjacent two flow paths. However, the number of the multiple flow paths is not limited to four or eight in Embodiments 1 and 2, and it is sufficient that the multiple flow paths 32, 34, 36, and 38 have at least four flow paths.

[0042] In addition, when multiple first flow paths 32 are connected to the fuel gas flow path 20 as in the above structure, the two first flow paths 32 may be connected in parallel to the fuel gas flow path 20. Based on this structure, for any first flow path 32, efficient heat exchange can be carried out between it and the adjacent second flow path 34. However, in other embodiments, the two first flow paths 32 may be connected in series to the fuel gas flow path 20. The two second flow paths 34, the two third flow paths 36, and the two fourth flow paths 38 can be configured in the same manner as the two first flow paths 32.

[0043] (Embodiment 3)

[0044] Refer to Figure 3 FIG. (B) to describe the heat exchanger 210 of Embodiment 3. As Figure 3 shown in (B) of FIG., in the heat exchanger 210 of Embodiment 3, the arrangement of the multiple flow paths 32, 34, 36, and 38 is different from that of the heat exchanger 10 of Embodiment 1. In the heat exchanger 210, the multiple flow paths 32, 34, 36, and 38 are arranged in a manner that circulates once from the first flow path 32 to the fourth flow path 38. The first flow path 32 is adjacent to the fourth flow path 38. That is, the first flow path 32 is configured to also perform heat exchange with the fourth flow path 38. Based on this structure, for all of the first flow path 32 to the fourth flow path 38, they can be adjacent to another two flow paths. By further improving the efficiency of heat exchange, further miniaturization of the heat exchanger 210 can be achieved.

[0045] Specifically, the heat exchanger 210 includes a housing 240. The housing 240 has a cylindrical peripheral wall 42 same as that of Embodiment 1 and a plurality of plate-like partition walls 244 located inside the peripheral wall 42. Among the plurality of partition walls 244, one ends of each are combined with each other, and the other ends of each are combined with the peripheral wall 42.

[0046] (Embodiment 4)

[0047] Refer to Figure 4In (A), the heat exchanger 310 of Example 4 will be described. As Figure 4 As shown in (A) of the figure, in the heat exchanger 310 of Example 4, in addition to the plurality of flow paths 32, 34, 36, 38 in Example 1, the plurality of flow paths 32, 34, 36, 38, 332, 334 further include a second first flow path 332 and a second second flow path 334. In this regard, the heat exchanger 310 of Example 4 is different from the heat exchanger 10 of Example 1. The second first flow path 332 is adjacent to the fourth flow path 38 and exchanges heat with the fourth flow path 38. The second first flow path 332 is the same as the first flow path 32 of Example 1 and is connected to the fuel gas flow path 20. The second second flow path 334 is adjacent to the second first flow path 332 and exchanges heat with the second first flow path 332. The second second flow path 334 is the same as the second flow path 34 of Example 1 and is connected to the oxidant gas flow path 24.

[0048] In the structure of Example 4, the third flow path 36 and the fourth flow path 38 through which cooling water flows are located in the central part of the flow path arrangement formed by arranging the plurality of flow paths 32, 34, 36, 38, 332, 334 in parallel. Compared with the fuel gas as a gas and the exhaust gas of the fuel gas, the cooling water as a liquid has a higher heat exchange capacity. Therefore, if the two flow paths 36, 38 through which cooling water flows are arranged in the central part of the arrangement of the plurality of flow paths 32, 34, 36, 38, 332, 334, the heat exchange efficiency can be effectively improved. In addition, the second first flow path 332 in the present embodiment is an example of the "first flow path" in the present technology. The fourth flow path 38 in the present embodiment is an example of the "second flow path" in the present technology. The third flow path 36 in the present embodiment is an example of the "third flow path" in the present technology. The fourth flow path 38 in the present embodiment is an example of the "fourth flow path" in the present technology.

[0049] (Example 5)

[0050] Refer to Figure 4 In (B), the heat exchanger 410 of Example 5 will be described. As Figure 4As shown in (B) of FIG. 0, the heat exchanger 410 of Embodiment 5 includes a plurality of flow paths 32, 434, 36, 438 including the first flow path 32 and the third flow path 36 which are the same as those of Embodiment 1, and the second flow path 434 and the fourth flow path 438. The second flow path 434 is connected to the second cooling water flow path 30. The fourth flow path 438 is connected to the oxidant gas flow path 24. In these respects, the structure of the heat exchanger 410 of Embodiment 5 is different from that of the heat exchanger 10 of Embodiment 1. In the structure of Embodiment 5 described above, in the flow path arrangement of the four flow paths 32, 434, 36, 438 in the heat exchanger 410, the two flow paths 434, 36 through which cooling water flows are arranged in the central portion of the flow path arrangement. Therefore, the efficiency of heat exchange can be effectively improved.

[0051] In the heat exchanger 410 of Embodiment 5, the flow path arrangement of the plurality of flow paths 32, 434, 36, 438 is also different from that of the heat exchanger 10 of Embodiment 1. The second flow path 434 is adjacent to the first flow path 32 and exchanges heat with the first flow path 32. The third flow path 36 is adjacent to the second flow path 434 and exchanges heat with the second flow path 434. The fourth flow path 438 is adjacent to the third flow path 36 and exchanges heat with the third flow path 36. Also, in the heat exchanger 410, the first flow path 32 is configured to be adjacent to the fourth flow path 438 and exchange heat with the fourth flow path 438. Based on this structure, for all of the first flow path 32 to the fourth flow path 438, it can be adjacent to the other two flow paths. By further improving the efficiency of heat exchange, further miniaturization of the heat exchanger 410 can be achieved.

[0052] Also, the second flow path 434 is surrounded by the first flow path 32 outside the range adjacent to the third flow path 36. The third flow path 36 is surrounded by the fourth flow path 438 outside the range adjacent to the second flow path 434. Based on this structure, the area where the first flow path 32 is adjacent to the second flow path 434 and the area where the fourth flow path 438 is adjacent to the third flow path 36 can be increased, and the efficiency of heat exchange can be improved. In addition, useless heat exchange between the second flow path 434 and the third flow path 36 and the outside can be suppressed.

[0053] Although not particularly limited, the heat exchanger 410 includes a housing 440. The housing 440 has a cylindrical peripheral wall 42 similar to that of the first embodiment and a plurality of partition walls 444 located within the peripheral wall 42. The plurality of partition walls 444 include a cylindrical first partition wall 444a and a plate-like second partition wall 444b. The first partition wall 444a extends along the inner surface of the peripheral wall 42. A gap is provided between the first partition wall 444a and the peripheral wall 42. The second partition wall 444b extends between the second wall 42b and the fourth wall 42d of the peripheral wall 42. The second partition wall 444b is configured to partition together the space divided by the first partition wall 444a and the space divided by the peripheral wall 42.

[0054] (Embodiment 6)

[0055] Refer to Figure 5 The heat exchanger 510 of Embodiment 6 will be described. As Figure 5 shown, in the heat exchanger 510 of Embodiment 6, the flow path arrangement of the plurality of flow paths 32, 434, 36, 438 is different from that of the heat exchanger 410 of Embodiment 5. The first flow path 32, the second flow path 434, the third flow path 36, and the fourth flow path 438 each extend along the same central axis C. The first flow path 32 is located in the innermost side and is arranged outward in the order of the second flow path 434, the third flow path 36, and the fourth flow path 438. The entire outer periphery of the first flow path 32 is surrounded by the second flow path 434. The entire outer periphery of the second flow path 434 is surrounded by the third flow path 36. The entire outer periphery of the third flow path 36 is surrounded by the fourth flow path 438. Specifically, the first flow path 32, the second flow path 434, the third flow path 36, and the fourth flow path 438 are arranged in a concentric circle shape centered on the central axis C. Based on this structure, in all of the first flow path 32 to the fourth flow path 438, the area adjacent to other flow paths can be increased, and the heat exchange efficiency can be improved. In addition, except for the outermost fourth flow path 438, useless heat exchange between each of the flow paths 32, 434, 36 and the outside can be suppressed.

[0056] In addition, through the above flow path arrangement, in the flow path arrangement of the four flow paths 32, 434, 36, 438 in the heat exchanger 510, the two flow paths 434, 36 through which the cooling water flows are also arranged in the central part of the flow path arrangement. Therefore, the heat exchange efficiency can be effectively improved.

[0057] Although not particularly limited, the heat exchanger 510 includes a housing 540. The housing 540 has a cylindrical peripheral wall 542 and a plurality of cylindrical partition walls 544 located within the peripheral wall 542. The plurality of partition walls 544 include a first partition wall 544a, a second partition wall 544b that surrounds the entire outer peripheral surface of the first partition wall 544a, and a third partition wall 544c that surrounds the entire outer peripheral surface of the second partition wall 544b.

[0058] (Embodiment 7)

[0059] Refer to Figure 6 The heat exchanger 610 of Embodiment 7 will be described. As Figure 6 shown, the heat exchanger 610 of Embodiment 7 includes a plurality of flow paths 32, 634, 36, 638 including the first flow path 32 and the third flow path 36 that are the same as those of Embodiment 1, and the second flow path 634 and the fourth flow path 638. The second flow path 634 is connected to the fuel exhaust gas flow path 22, and the fourth flow path 638 is connected to the oxidant exhaust gas flow path 26. In this regard, the heat exchanger 610 of Embodiment 6 is different from the heat exchanger 10 of Embodiment 1. In this case, it is also configured such that in the first flow path 32 and the third flow path 36, fluids with relatively low temperatures flow respectively, and in the second flow path 634 and the fourth flow path 638, fluids with relatively high temperatures flow respectively. Therefore, the flow paths 32, 36 for the low-temperature fluid and the flow paths 634, 638 for the high-temperature fluid are alternately arranged, and efficient heat exchange can be performed between adjacent two flow paths each.

[0060] In addition, in Embodiments 1 to 7, various combinations of a plurality of flow paths in the heat exchangers 10, 110, 210, 310, 410, 510, 610 have been described, but the combination of the plurality of flow paths is not particularly limited. It is only necessary that either the fuel gas flow path 20 or the first cooling water flow path 28 is connected to the first flow path and the third flow path respectively. Moreover, it is only necessary that either the fuel exhaust gas flow path 22, the oxidant gas flow path 24, the oxidant exhaust gas flow path 26, or the second cooling water flow path 30 is connected to the second flow path and the fourth flow path respectively.

Claims

1. A heat exchanger for a fuel cell, wherein, Comprising: A first flow path; A second flow path, which is adjacent to the first flow path and exchanges heat with the first flow path; A third flow path, which is adjacent to the second flow path and exchanges heat with the second flow path; And A fourth flow path, which is adjacent to the third flow path and exchanges heat with the third flow path, Either a flow path for fuel gas supplied to the fuel cell or a flow path for cooling water supplied to the fuel cell is connected to the first flow path and the third flow path respectively; Either a flow path for fuel exhaust gas discharged from the fuel cell, a flow path for oxidant gas supplied to the fuel cell, a flow path for oxidant exhaust gas discharged from the fuel cell, or a flow path for the cooling water discharged from the fuel cell is connected to the second flow path and the fourth flow path respectively.

2. The heat exchanger according to claim 1, wherein The first flow path is also adjacent to the fourth flow path and exchanges heat with the fourth flow path.

3. The heat exchanger according to claim 1, wherein At least one of the first flow path and the fourth flow path surrounds the second flow path and the third flow path.

4. The heat exchanger according to claim 3, wherein The first flow path, the second flow path, the third flow path, and the fourth flow path are arranged in a concentric circle manner.

5. The heat exchanger according to any one of claims 1 to 4, wherein A flow path for the fuel gas is connected to the first flow path, A flow path for the discharged cooling water is connected to the second flow path, A flow path for the supplied cooling water is connected to the third flow path, A flow path for the oxidant gas is connected to the fourth flow path.

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