fuel cells

Abstract

To increase the cooling effect of fuel cell cells using porous materials, thereby ensuring sufficient cooling even when the fuel cell is operating at high output. [Solution] The FC stack 11 consists of multiple fuel cell cells 13 stacked on top of each other, with a porous body 19 arranged between adjacent fuel cell cells 13 to form a flow channel for cooling water. The porous body 19 has multiple through holes 20 that penetrate in the direction of the cooling water flow. The multiple through holes 20 are arranged at intervals IV along the longitudinal direction X of the porous body 19, perpendicular to the direction of the cooling water flow.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a fuel cell that generates electricity by receiving supplies of fuel and an oxidant.

Background Art

[0002] Conventionally, as this type of technology, for example, a "fuel cell stack system" described in Patent Document 1 below is known. This system includes a fuel cell in which a plurality of fuel cells are stacked, an anode gas flow path (fuel supply passage) for supplying fuel to the fuel cell, a cathode gas flow path (oxidant supply passage) for supplying an oxidant to the fuel cell, and a porous body that is disposed between adjacent fuel cells and constitutes a flow path through which a cooling medium flows. In this system, the fuel cell is cooled by causing the cooling medium to flow through the porous body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=!]] However, in the fuel cell described in Patent Document 1, the fuel cell was cooled by causing a cooling medium to flow through the porous body. However, since the amount of heat generation increases when the fuel cell has a high output, there was a concern that the cooling of the fuel cell would become insufficient.

[0005] This disclosed technology has been made in view of the above circumstances, and its object is to enable an increase in the cooling effect of the fuel cell by the porous body and to ensure a sufficient cooling effect even when the fuel cell has a high output.

Means for Solving the Problems

[0006] To achieve the above objective, the technology described in claim 1 is a fuel cell in which a plurality of fuel cell cells are stacked and a porous body constituting a flow path for a cooling medium is arranged between adjacent fuel cell cells, wherein the porous body is provided with a plurality of through holes that penetrate in the direction in which the cooling medium flows.

[0007] According to the above technology configuration, each fuel cell is cooled by flowing a cooling medium through a porous material placed between multiple fuel cell cells, thereby cooling the entire fuel cell. In this configuration, the cooling medium is drawn up by the capillary force of the porous material. Furthermore, the cooling medium vaporizes in the porous material due to heat from the fuel cell cells, thereby removing heat from the fuel cell cells and cooling them. In addition, the specific surface area of ​​the porous material with respect to air increases due to the inner surface area of ​​the multiple through-holes, increasing the amount of cooling medium vaporized in the porous material.

[0008] To achieve the above objective, the technology described in claim 2 is characterized in that, in the technology described in claim 1, the plurality of through holes are spaced apart along the longitudinal direction of the porous body in a direction perpendicular to the direction in which the cooling medium flows, and the spacing differs between the middle and both ends in the longitudinal direction.

[0009] According to the configuration of the above technology, in addition to the operation of the technology described in claim 1, the heat generated by the fuel cell cell with the porous body in between may differ between the middle and both ends in the longitudinal direction. In this case, the spacing between the multiple through holes is adjusted between the middle and both ends in the longitudinal direction. This adjusts the amount of vaporization of the cooling medium in the porous body in the longitudinal direction.

[0010] To achieve the above objective, the technology described in claim 3 is intended to be the technology described in claim 2, wherein the spacing is narrowest in the middle portion in the longitudinal direction.

[0011] According to the configuration of the above technology, in addition to the effects of the technology described in claim 2, the spacing between the multiple through holes is narrowest in the middle portion in the longitudinal direction, so the amount of vaporization of the cooling medium in the porous body is greater in the middle portion in the longitudinal direction.

[0012] To achieve the above objective, the technology described in claim 4 is characterized in that, in the technology described in claim 1, the plurality of through holes are spaced apart along the longitudinal direction of the porous body in a direction perpendicular to the direction in which the cooling medium flows, and the cross-sectional area of ​​the through holes differs between the middle and both ends in the longitudinal direction.

[0013] According to the configuration of the above technology, in addition to the operation of the technology described in claim 1, the heat generated by the fuel cell cell with the porous body in between may differ between the middle and both ends in the longitudinal direction. In this case, the cross-sectional area of ​​the multiple through holes is adjusted between the middle and both ends in the longitudinal direction. This adjusts the amount of vaporization of the cooling medium in the porous body in the longitudinal direction.

[0014] To achieve the above objective, the technology described in claim 5 is intended to be the technology described in claim 4 in which the cross-sectional area of ​​the through hole is largest in the middle portion in the longitudinal direction.

[0015] According to the configuration of the above technology, in addition to the effects of the technology described in claim 4, the cross-sectional area of ​​the multiple through holes is largest in the middle part in the longitudinal direction, so the amount of vaporization of the cooling medium in the porous body is greater in the middle part in the longitudinal direction.

[0016] To achieve the above objective, the technology described in claim 6 is characterized in that, in the technology described in claim 1, the porous body is formed from a single material, and the porosity of the porous body differs between the middle and both ends in the longitudinal direction of the porous body in a direction perpendicular to the direction in which the cooling medium flows.

[0017] According to the configuration of the above technology, in addition to the operation of the technology described in claim 1, the heat generated by the fuel cell cell in which the porous body is placed may differ between the middle section and both ends in the longitudinal direction. In this case, the porosity of the porous body is adjusted between the middle section and both ends in the longitudinal direction. This adjusts the amount of vaporization of the cooling medium in the porous body between the middle section and both ends.

[0018] In order to achieve the above object, the technique according to claim 7 is, in the technique according to claim 6, characterized in that the porosity of the porous body is highest at the middle portion in the longitudinal direction.

[0019] According to the configuration of the above technique, in addition to the action of the technique according to claim 6, since the porosity of the porous body is highest at the middle portion in the longitudinal direction, the vaporization amount of the cooling medium in the porous body increases at the middle portion.

[0020] In order to achieve the above object, the technique according to claim 8 is, in the technique according to claim 1, characterized in that the porous body is formed of one material, and the porosity of the porous body is different between the middle portion and both end portions in the direction in which the cooling medium flows.

[0021] According to the configuration of the above technique, in addition to the action of the technique according to claim 1, the heat generation of the fuel cell in which the porous body is disposed therebetween may be different between the middle portion and both end portions in the direction in which the cooling medium flows. In this case, the porosity of the porous body is adjusted between the middle portion and the both end portions. Thereby, the vaporization amount of the cooling medium in the porous body is adjusted between the middle portion and the both end portions.

[0022] In order to achieve the above object, the technique according to claim 9 is, in the technique according to claim 8, characterized in that the porosity of the porous body is highest at the middle portion in the direction in which the cooling medium flows.

[0023] According to the configuration of the above technique, in addition to the action of the technique according to claim 8, since the porosity of the porous body is highest at the middle portion in the direction in which the cooling medium flows, the vaporization amount of the cooling medium in the porous body increases at the middle portion.

[0024] In order to achieve the above object, the technique according to claim 10 is, in the technique according to any one of claims 1 to 9, characterized in that the porosity of the porous body is 0 in the vicinity where the porous body contacts the adjacent fuel cells.

[0025] According to the configuration of the above technology, in addition to the operation of the technology described in any one of claims 1 to 9, since the porosity is 0 in the vicinity where the porous body contacts the fuel cell, the thermal resistance between the porous body and the fuel cell is reduced.

Advantages of the Invention

[0026] According to the technology described in claim 1, the cooling effect of the fuel cell by the porous body can be increased, and a sufficient cooling effect can be ensured even when the fuel cell has a high output.

[0027] According to the technology described in claim 2, in addition to the effect of the technology described in claim 1, the temperature of the fuel cell can be made uniform in the longitudinal direction.

[0028] According to the technology described in claim 3, in addition to the effect of the technology described in claim 2, the cooling effect of the fuel cell can be enhanced at the middle part in the longitudinal direction.

[0029] According to the technology described in claim 4, in addition to the effect of the technology described in claim 1, the temperature of the fuel cell can be made uniform in the longitudinal direction.

[0030] According to the technology described in claim 5, in addition to the effect of the technology described in claim 4, the cooling effect of the fuel cell can be enhanced at the middle part in the longitudinal direction.

[0031] According to the technology described in claim 6, in addition to the effect of the technology described in claim 1, the temperature of the fuel cell can be made uniform in the longitudinal direction.

[0032] According to the technology described in claim 7, in addition to the effect of the technology described in claim 6, the cooling effect of the fuel cell can be enhanced at the middle part in the longitudinal direction.

[0033] According to the technology described in claim 8, in addition to the effect of the technology described in claim 1, the temperature of the fuel cell can be made uniform in the direction in which the cooling medium flows.

[0034] According to the technology described in claim 9, in addition to the effects of the technology described in claim 8, the cooling effect of the fuel cell can be enhanced in the intermediate portion in the direction in which the cooling medium flows.

[0035] According to the technology described in claim 10, in addition to the effects of the technology described in any one of claims 1 to 9, heat can be more easily transferred from the fuel cell to the porous body, thereby enhancing the cooling effect of the fuel cell. [Brief explanation of the drawing]

[0036] [Figure 1] A schematic diagram showing a fuel cell system according to the first embodiment. [Figure 2] A schematic diagram showing the cooling system according to the first embodiment. [Figure 3] This is an illustrative diagram showing a part of the FC stack shown in Figure 2, relating to the first embodiment. [Figure 4] A schematic diagram showing the stacked structure of a fuel cell cell according to the first embodiment. [Figure 5] A perspective view relating to the first embodiment, showing a porous body and a pair of fuel cell cells flanking it on both sides. [Figure 6] A plan view relating to the first embodiment, showing a porous body and a pair of fuel cell cells flanking it on both sides. [Figure 7] Figure 6 shows a cross-sectional view along line AA illustrating a porous body and a pair of fuel cell cells flanking it on both sides, according to the first embodiment. [Figure 8] A plan view relating to a second embodiment, showing a porous body and a pair of fuel cell cells flanking it on both sides. [Figure 9] A plan view relating to a third embodiment, showing a porous body and a pair of fuel cell cells flanking it on both sides. [Figure 10] A plan view relating to the fourth embodiment, showing a porous body and a pair of fuel cell cells flanking it on both sides. [Figure 11] A perspective view showing a porous body according to the fifth embodiment. [Figure 12]A perspective view showing a porous body according to the sixth embodiment. [Figure 13] A perspective view showing a porous body according to the seventh embodiment. [Figure 14] An enlarged cross-sectional view showing an image of the contact area between the fuel cell and the porous body according to the first embodiment. [Figure 15] An enlarged cross-sectional view showing an image of the contact area between the fuel cell and the porous body, relating to the seventh embodiment. [Figure 16] A perspective view showing a porous body according to the eighth embodiment. [Figure 17] An enlarged cross-sectional view showing an image of the contact area between the fuel cell and the porous body in contact with both sides thereof, relating to the eighth embodiment. [Figure 18] A perspective view showing a porous body according to the ninth embodiment. [Figure 19] An enlarged cross-sectional view showing an image of the contact area between the fuel cell and the porous body in contact with both sides thereof, relating to the ninth embodiment. [Modes for carrying out the invention]

[0037] The following describes an embodiment in which a fuel cell is implemented in a fuel cell system installed in an electric vehicle.

[0038] <First Embodiment> The first embodiment will be described in detail with reference to the drawings.

[0039] [Regarding the main components of a fuel cell system] Figure 1 shows a schematic configuration diagram of the fuel cell system 1 of this embodiment. As shown in Figure 1, the fuel cell system 1 of this embodiment comprises an FC stack 11, a hydrogen system 21, an air system 22, and a cooling system 23. Figure 2 shows a schematic diagram of the cooling system 23. Figure 3 shows an illustrative diagram of a part of the FC stack 11 shown in Figure 2.

[0040] [About FC stacks] The FC stack 11 generates electricity by receiving a supply of fuel and an oxidizer. In this embodiment, the fuel is hydrogen gas and the oxidizer is air. The FC stack 11 generates electricity by receiving a supply of hydrogen gas from the hydrogen system 21 and an air supply from the air system 22. The electricity generated by the FC stack 11 is supplied to a battery and an inverter (not shown). The cooling system 23 cools the FC stack 11 using cooling water. The FC stack 11 corresponds to an example of a "fuel cell" in this disclosed technology. The cooling water corresponds to an example of a "cooling medium" in this disclosed technology.

[0041] As shown in Figures 1 and 2, in this embodiment, the FC stack 11 is composed of multiple fuel cell cells 13 stacked on top of each other. Between adjacent fuel cell cells 13, block-shaped porous bodies 19 are placed to form channels through which cooling water flows. The porous body 19 is a material having numerous fine gaps or pores inside. Examples of porous bodies 19 include sponges, sponge-like materials, filters, porous ceramics, and porous metals. The porous body 19 has properties such as breathability and absorbency and is used in various fields.

[0042] [About hydrogen systems] The hydrogen system 21 is installed on the anode side of the FC stack 11. The hydrogen system 21 includes a hydrogen supply passage 31, a hydrogen discharge passage 32, and a filling passage 33.

[0043] The hydrogen supply passage 31 is a passage for supplying hydrogen gas from the hydrogen tank 41, where hydrogen gas is stored, to the FC stack 11. The hydrogen discharge passage 32 is a passage for discharging hydrogen gas (i.e., hydrogen off-gas) discharged from the FC stack 11.

[0044] The hydrogen supply passage 31 is equipped with a hydrogen tank 41, a hydrogen valve 51, a hydrogen pressure reducing valve 52, and an injector 53. The filling passage 33 is a passage for filling the hydrogen tank 41 with hydrogen gas from the filling port 42.

[0045] The hydrogen valve 51 is a valve that switches between supplying and shutting off hydrogen gas from the hydrogen tank 41 to the hydrogen supply passage 31, and is composed of multiple devices, such as a solenoid valve. The hydrogen pressure reducing valve 52 is a pressure regulating valve for reducing the pressure of hydrogen gas, and is composed of a solenoid valve, for example. The injector 53 is a device that injects hydrogen gas introduced from the hydrogen tank 41 to the downstream side, and is composed of a solenoid valve, for example. The injector 53 is configured to adjust the discharge pressure (hydrogen pressure) of hydrogen gas by adjusting the opening of the injection port by moving a needle valve, for example.

[0046] An exhaust and drain valve 57 is provided in the hydrogen discharge passage 32. The exhaust and drain valve 57 is a valve that switches between discharging and shutting off hydrogen off-gas and moisture from the FC stack 11, and is composed of, for example, a solenoid valve.

[0047] [Regarding the air system] The air system 22 is provided on the cathode side of the FC stack 11. The air system 22 includes an air supply passage 61, an air discharge passage 62, and an air compressor 71.

[0048] The air supply passage 61 is a passage for supplying air from outside the fuel cell system 1 to the FC stack 11. The air discharge passage 62 is a passage for discharging air (i.e., air-off gas) discharged from the FC stack 11.

[0049] The air compressor 71 is an electrically powered device that supplies air to the FC stack 11. In this embodiment, no devices such as air valves are provided in the air supply passage 61 between the air compressor 71 and the FC stack 11, or in the air discharge passage 62 downstream of the FC stack 11. In other words, the FC stack 11 in this embodiment is configured to receive air directly from the air compressor 71 and to discharge air-off gas directly to the outside from the FC stack 11.

[0050] [Regarding the cooling system] As shown in Figures 1 and 2, the cooling system 23 includes a cooling water circulation channel 81 that circulates cooling water through each porous body 19. A heat exchanger 82 and a water tank 83 are provided in the cooling water circulation channel 81.

[0051] The heat exchanger 82 is positioned downstream of the FC stack 11 on the cooling water circulation channel 81. In this embodiment, the heat exchanger 82 is configured so that the cooling water flowing through the cooling water circulation channel 81 can exchange heat with the hydrogen gas flowing through the hydrogen supply passage 31.

[0052] The water tank 83 is located upstream of the FC stack 11 on the cooling water circulation channel 81. The water tank 83 is configured to store the cooling water that has been heat-exchanged (cooled) and liquefied (condensed) in the heat exchanger 82.

[0053] The FC stack 11 is provided with an inlet shroud 85 on the cooling water inflow side and an outlet shroud 86 on the cooling water outflow side. The inlet shroud 85 covers the inflow side of the FC stack 11 to allow cooling water to flow into each of the inlet sides of the multiple porous bodies 19. The downstream end of the cooling water circulation channel 81 is connected to the inlet 85a of the inlet shroud 85. The outlet shroud 86 covers the outflow side of the FC stack 11 to collect the cooling water (water vapor) flowing out from the outlet sides of the multiple porous bodies 19. The upstream end of the cooling water circulation channel 81 is connected to the outlet 86a of the outlet shroud 86. The cooling water circulation channel 81 is composed of a closed loop through which only cooling water circulates. In other words, the cooling water circulation channel 81 is a closed channel that does not communicate with the outside.

[0054] As shown in Figure 2, cooling water flows through the central pipe 82a of the heat exchanger 82. Hydrogen gas supplied to the FC stack 11 flows around this central pipe 82a. Hydrogen gas at approximately 20°C flows into the heat exchanger 82. Cooling water at approximately 60°C flows into the central pipe 82a. In the heat exchanger 82, the hydrogen gas is heated to approximately 55°C and supplied to the FC stack 11. The cooling water is cooled from 60°C to approximately 52°C and flows into the water tank 83. The cooling water that flows from the water tank 83 to the FC stack 11 is drawn into the porous body 19 by the capillary force of the porous body 19.

[0055] As shown in Figure 3, a single fuel cell cell 13 consists of an electrode material 14 that serves as a heat source and a pair of separators 15 that sandwich the electrode material 14. Cooling water drawn into the porous body 19 is drawn in from the inlet side (lower side in Figure 3) by the capillary force of the porous body 19. At this time, the heat generated by the electrode material 14 is transferred to the porous body 19 via the separators 15, causing the cooling water inside the porous body 19 to change into water vapor, which then evaporates from the outlet side (upper side in Figure 3), releasing heat. The latent heat of vaporization of the porous body 19 at this time cools the fuel cell cell 13. The heat transfer coefficient of latent heat of vaporization is overwhelmingly higher than that of air cooling or water cooling.

[0056] [Regarding the configuration of fuel cell cells] Figure 4 shows a schematic diagram of the stacked structure of the fuel cell cell 13 of this embodiment. The fuel cell cell 13 comprises an electrode material 14 and a pair of separators 15 sandwiching the electrode material 14. The electrode material 14 includes a pair of gas diffusion layers 16 in contact with each separator 15, a catalyst layer 17 in contact with each gas diffusion layer 16, and an electrolyte membrane 18 sandwiched between the pair of catalyst layers 17.

[0057] [About the composition of porous materials] Figure 5 shows a perspective view of a single porous body 19 and a pair of fuel cell cells 13 flanking it. Figure 6 shows a plan view of a single porous body 19 and a pair of fuel cell cells 13 flanking it. Figure 7 shows a cross-sectional view of a single porous body 19 and a pair of fuel cell cells 13 flanking it, as shown by line AA in Figure 6. Here, for convenience, the number of through-holes 20 in Figure 5 and the number of through-holes 20 in Figure 6 differ by one.

[0058] As shown in Figures 5 to 7, the porous body 19 has a plurality of through holes 20 that penetrate in the direction Y through which the cooling water flows. In this embodiment, the flow path cross-section of each through hole 20 is rectangular. The flow path cross-sectional shape of the through hole 20 may be a polygon other than a rectangle or a circle.

[0059] Here, the multiple through-holes 20 are arranged at intervals IV (see Figure 6) along the longitudinal direction X of the porous body 19 (which is also the direction in which the through-holes 20 are arranged), perpendicular to the direction Y in which the cooling water flows. In this embodiment, the multiple through-holes 20 are arranged in a line in the center of the short direction Z of the porous body 19, perpendicular to the direction Y in which the cooling water flows. Also in this embodiment, the multiple through-holes 20 are arranged at equal intervals IV.

[0060] [Regarding the operation of the fuel cell system] In the fuel cell system 1 configured as described above, the hydrogen gas supplied to the FC stack 11 from the hydrogen supply passage 31 is used for power generation in the FC stack 11, and then discharged from the FC stack 11 as hydrogen off-gas to the outside of the fuel cell system 1 via the hydrogen discharge passage 32. Similarly, the air supplied to the FC stack 11 from the air supply passage 61 is used for power generation in the FC stack 11, and then discharged from the FC stack 11 as air off-gas to the outside of the fuel cell system 1 via the air discharge passage 62.

[0061] The electricity generated by the FC stack 11 is either supplied to the battery to charge it, or supplied to the inverter to drive it. The inverter is also powered by the battery.

[0062] [Regarding the operation and effects of fuel cell systems] According to the configuration of the fuel cell system 1 of this embodiment described above, the FC stack 11 is cooled by circulating cooling water through the porous body 19 via the cooling water circulation channel 81. In addition, the cooling water is cooled by heat exchange with hydrogen gas in the cooling water circulation channel 81. Since the cooling water circulation channel 81 is configured as a closed loop in which only cooling water circulates, the cooling water is not released to the outside. Therefore, the cooling water can be used efficiently to cool the FC stack 11 while suppressing the consumption of cooling water.

[0063] According to the configuration of this embodiment, the air system 22 includes an air compressor 71, and air is supplied directly to the FC stack 11 from the air compressor 71, and air-off gas is directly discharged from the FC stack 11. Therefore, no air valves or the like are provided on the supply side of the air system 22 other than the air compressor 71, nor are any air valves or the like provided on the discharge side of the air system 22. As a result, the air system 22 can be simplified, and the cost of the fuel cell system 1 can be reduced.

[0064] [Regarding the operation and effects of FC stacks] In this embodiment of the FC stack 11 configuration, cooling water is circulated through a porous body 19 placed between multiple fuel cell cells 13, thereby cooling each fuel cell 13 and the entire FC stack 11. In this configuration, the cooling water is drawn up through the porous body 19 by its capillary force. Furthermore, the cooling water vaporizes in the porous body 19 due to heat from the FC stack 11, thereby removing heat from the fuel cell cells 13 and cooling them. In addition, the specific surface area of ​​the porous body 19 with respect to air increases due to the inner surface area of ​​the multiple through holes 20, increasing the amount of cooling water vaporized in the porous body 19. As a result, the cooling effect of the fuel cell cells 13 by the porous body 19 can be increased, and sufficient cooling effect can be ensured even when the FC stack 11 is at high output.

[0065] <Second Embodiment> Next, the second embodiment will be described in detail with reference to the drawings. In the following description, components equivalent to those in the first embodiment will be denoted by the same reference numerals, and the differences will be the focus of the description.

[0066] [About the composition of porous materials] This embodiment differs from the first embodiment in terms of the configuration of the porous body 19. Figure 8 shows a plan view of this embodiment, showing a porous body 19 and a pair of fuel cell cells 13 flanking it on both sides. The multiple through-holes 20 are arranged at intervals IV along the longitudinal direction X, which is perpendicular to the direction Y in which the cooling water flows. In this embodiment, the through-holes 20 are arranged in two rows, one row at each end of the short-side direction Z of the porous body 19 (positions in contact with the fuel cell cells 13), which is perpendicular to the direction Y in which the cooling water flows. In addition, the cross-sectional area of ​​the through-holes 20 is smaller than that of the first embodiment, but the number of through-holes 20 is greater than that of the first embodiment. In this embodiment as well, the multiple through-holes 20 are arranged at equal intervals IV.

[0067] [Regarding the operation and effects of FC stacks] According to the configuration of the FC stack 11 in this embodiment, the same operation and effects as in the first embodiment can be obtained. Furthermore, in this embodiment, since the multiple through holes 20 are positioned in contact with the fuel cell 13, heat from the fuel cell 13 can be easily released through the through holes 20.

[0068] <Third Embodiment> Next, a third embodiment will be described in detail with reference to the drawings.

[0069] [About the composition of porous materials] This embodiment differs from the previous embodiments in terms of the configuration of the porous body 19. Figure 9 shows a plan view of this embodiment, comprising a porous body 19 and a pair of fuel cell cells 13 flanking it. In this embodiment, unlike the first embodiment, the spacing IV of the multiple through holes 20 arranged in a row in the longitudinal direction X differs between the middle and both ends in the longitudinal direction X. In particular, in this embodiment, the spacing IV is narrowest in the middle of the longitudinal direction X, and wider at both ends in the longitudinal direction X than in the middle. This arrangement corresponds to the case where the temperature distribution of the fuel cell 13 is higher in the central part of the fuel cell 13.

[0070] [Regarding the operation and effects of FC stacks] In this embodiment of the FC stack 11 configuration, the heat generated by the fuel cell cells 13 with the porous body 19 in between may differ between the middle and both ends in the longitudinal direction X. In this case, the spacing IV of the multiple through holes 20 is adjusted between the middle and both ends in the longitudinal direction X. This adjusts the amount of cooling water vaporized in the porous body 19 in the longitudinal direction X. As a result, the temperature of the fuel cell cells 13 can be made uniform in the longitudinal direction X.

[0071] According to the configuration of this embodiment, the spacing IV between the multiple through holes 20 is narrowest in the middle section in the longitudinal direction X, so the amount of cooling water vaporized in the porous body 19 is greater in the middle section in the longitudinal direction X. Therefore, the cooling effect of the fuel cell cell 13 can be enhanced in the middle section in the longitudinal direction X.

[0072] <Fourth Embodiment> Next, a fourth embodiment will be described in detail with reference to the drawings.

[0073] [About the composition of porous materials] This embodiment differs from the previous embodiments in terms of the configuration of the porous body 19. Figure 10 shows a plan view of this embodiment, showing one porous body 19 and a pair of fuel cell cells 13 flanking it. In this embodiment, unlike the first embodiment, the cross-sectional area of ​​the multiple through holes 20 differs between the middle and both ends in the longitudinal direction X. In particular, in this embodiment, the cross-sectional area is largest in the middle in the longitudinal direction X and smallest at both ends in the longitudinal direction X. This arrangement corresponds to the case where the temperature distribution of the fuel cell 13 is higher in the central part of the fuel cell 13.

[0074] [Regarding the operation and effects of FC stacks] In this embodiment of the FC stack 11 configuration, the heat generated by the fuel cell cells 13 with the porous body 19 in between may differ between the middle and both ends in the longitudinal direction X. In this case, the cross-sectional area of ​​the multiple through holes 20 is adjusted between the middle and both ends in the longitudinal direction X. This adjusts the amount of cooling water vaporized in the porous body 19 in the longitudinal direction X. As a result, the temperature of the fuel cell cells 13 can be made uniform in the longitudinal direction X.

[0075] According to the configuration of this embodiment, the cross-sectional area of ​​the multiple through holes 20 is largest in the middle portion in the longitudinal direction X, so the amount of cooling water vaporized in the porous body 19 is greater in the middle portion in the longitudinal direction X. Therefore, the cooling effect of the fuel cell cell 13 can be enhanced in the middle portion in the longitudinal direction X.

[0076] <Fifth Embodiment> Next, a fifth embodiment will be described in detail with reference to the drawings.

[0077] [About the composition of porous materials] This embodiment differs from the first embodiment in terms of the configuration of the porous body 19. Figure 11 shows a perspective view of a porous body 19 according to this embodiment. In this embodiment, as in the first embodiment, the porous body 19 has a plurality of through holes 20 arranged in a row in the longitudinal direction X. The plurality of through holes 20 are arranged at equal intervals IV.

[0078] In this embodiment, the porous body 19 is formed from a single material, but its porosity differs depending on the part. That is, the porosity of the porous body 19 differs between the middle section 19a (shown with dense dots) and both ends 19b and 19c (shown with coarse dots) in the longitudinal direction X. In particular, in this embodiment, the porosity of the porous body 19 is highest in the middle section 19a, and lower at both ends 19b and 19c than in the middle section 19a. Here, "porosity" refers to the ratio of the volume of pores to the volume of the porous body 19.

[0079] [Regarding the operation and effects of FC stacks] In this embodiment of the FC stack 11 configuration, the heat generated by the fuel cell cells 13 with the porous body 19 in between may differ between the middle and both ends in the longitudinal direction X. In this case, the porosity of the porous body 19 is adjusted between the middle and both ends in the longitudinal direction X. This adjusts the amount of cooling water vaporized in the porous body 19 between the middle and both ends. As a result, the temperature of the fuel cell cells 13 can be made uniform in the longitudinal direction X.

[0080] According to the configuration of this embodiment, the porosity of the porous body 19 is highest in the middle section along the longitudinal direction X, so the amount of cooling water vaporized in the porous body 19 is greater in the middle section. Therefore, the cooling effect of the fuel cell can be enhanced in the middle section along the longitudinal direction X.

[0081] <Sixth Embodiment> Next, the sixth embodiment will be described in detail with reference to the drawings.

[0082] [About the composition of porous materials] This embodiment differs from the fifth embodiment in terms of the configuration of the porous body 19. As shown in Figure 12, in this embodiment, similar to the fifth embodiment, the porous body 19 has a plurality of through holes 20 arranged in a row in the longitudinal direction X. The plurality of through holes 20 are arranged at equal intervals IV.

[0083] In this embodiment as well, the porous body 19 is formed from a single material, but its porosity differs depending on the part. That is, unlike in the fifth embodiment, the porosity of the porous body 19 differs between the intermediate part 19d (indicated by dense dots) and both ends 19e, 19f (indicated by coarse dots) in the direction Y through which the cooling water flows. In particular, in this embodiment, the porosity of the porous body 19 is highest in the intermediate part 19d, and lower at both ends 19e, 19f than in the intermediate part 19d.

[0084] [Regarding the operation and effects of FC stacks] In this embodiment of the FC stack 11 configuration, the heat generated by the fuel cell cells 13 with the porous body 19 in between may differ between the middle section and both ends in the direction Y through which the cooling water flows. In this case, the porosity of the porous body 19 is adjusted between the middle section and both ends. This adjusts the amount of cooling water vaporized in the porous body 19 between the middle section and both ends. As a result, the temperature of the fuel cell cells 13 can be made uniform in the direction Y through which the cooling water flows.

[0085] According to the configuration of this embodiment, the porosity of the porous body 19 is highest in the intermediate portion in the direction Y through which the cooling water flows, so the amount of cooling water vaporized in the porous body 19 is greater in the intermediate portion. Therefore, the cooling effect of the fuel cell cell 13 can be enhanced in the intermediate portion in the direction Y through which the cooling water flows.

[0086] <Seventh Embodiment> Next, the seventh embodiment will be described in detail with reference to the drawings.

[0087] [About the composition of porous materials] This embodiment differs from the previous embodiments in terms of the configuration of the porous body 19. Figure 13 shows a perspective view of one porous body 19 according to this embodiment. In this embodiment, as in the first embodiment, the porous body 19 has a plurality of through holes 20 arranged in a row in the longitudinal direction X. The plurality of through holes 20 are arranged at equal intervals IV.

[0088] In this embodiment, the porosity of the porous body 19 is 0 near where the porous body 19 is in contact with adjacent fuel cell cells 13. That is, as shown in Figure 13, the porous body 19 is formed from a single material, but the porosity of the porous body 19 differs between the middle section 19g (indicated by dense dots) and both ends 19h, 19i (indicated by coarse dots) in the short-side direction Z. In particular, in this embodiment, the porosity of the porous body 19 is "0" at both ends 19h, 19i, while the middle section 19g has a certain degree of porosity.

[0089] Figure 14 shows an enlarged cross-sectional view of the contact area between the fuel cell 13 and the porous body 19 according to the first embodiment. Figure 15 shows an enlarged cross-sectional view of the contact area between the fuel cell 13 and the porous body 19 according to this embodiment. As shown in Figure 14, in the first embodiment, there is a gap at the contact area between the fuel cell 13 and the porous body 19, resulting in poor contact. As a result, thermal resistance is generated between the fuel cell 13 and the porous body 19.

[0090] In contrast, as shown in Figure 15, in this embodiment, there is no gap at the contact point between the fuel cell cell 13 and the porous body 19, and the contact state is improved. That is, in this embodiment, the porous body 19 is in close contact with the fuel cell cell 13 at the end 19h where the porosity is "0". As a result, the thermal resistance between the fuel cell cell 13 and the porous body 19 is reduced.

[0091] [Regarding the operation and effects of FC stacks] According to the configuration of the FC stack 11 in this embodiment, the porosity of the porous body 19 is 0 near where it contacts the fuel cell 13, thus reducing the thermal resistance between the porous body 19 and the fuel cell 13. As a result, heat is more easily transferred from the fuel cell 13 to the porous body 19, thereby enhancing the cooling effect of the fuel cell 13.

[0092] In this embodiment, the porosity of the porous body 19 is set to 0 near the fuel cell cell 13 in a configuration similar to that of the first embodiment, but a similar configuration may be added to the configurations of the second to sixth embodiments.

[0093] <Eighth Embodiment> Next, the eighth embodiment will be described in detail with reference to the drawings.

[0094] [About the composition of porous materials] This embodiment differs from the seventh embodiment in terms of the configuration of the porous body 19. Figure 16 shows a perspective view of one porous body 19 according to this embodiment. As shown in Figure 16, the porous body 19 of this embodiment has a configuration that is generally the same as that of the seventh embodiment.

[0095] Figure 17 shows an enlarged cross-sectional view of the contact area between the fuel cell cell 13 and the porous body 19 that is in contact with both sides thereof, according to this embodiment. In this embodiment, the porosity of the porous body 19 is 0 near where the porous body 19 is in contact with an adjacent fuel cell cell 13. That is, as shown in Figure 17, the end portion 19h of the porous body 19 in contact with the right side of the fuel cell cell 13 includes a portion 19ha where the porosity is "0" and a portion 19hb that is not in contact with the fuel cell cell 13 and has a climate factor of "not 0". This portion with a porosity of "not 0" (slightly greater than 0) constitutes a "gas flow path". Similarly, the end portion 19i of the porous body 19 in contact with the left side of the fuel cell cell 13 includes a portion 19ia where the porosity is "0" and a portion 19ib that is not in contact with the fuel cell cell 13 and has a climate factor of "not 0" (slightly greater than 0). This portion with a porosity of "not 0" constitutes a "gas flow path".

[0096] [Regarding the operation and effects of FC stacks] The configuration of the FC stack 11 in this embodiment allows for the same operation and effects as in the seventh embodiment. In addition, in this embodiment, the ends 19h and 19i of the porous body 19 include portions 19ha and 19ia that are in contact with the fuel cell cell 13 and have a porosity of "0", and portions 19hb and 19ib that are not in contact with the fuel cell cell 13 and have a climate factor that is not "0" (slightly greater than 0), with the portions with a porosity that are not "0" constituting a "gas flow path". That is, the portions 19ha and 19ia with a porosity of "0" can function as separators for the fuel cell cell 13. Therefore, as shown in Figure 17, separators can be omitted from the contact area between the porous body 19 and the fuel cell cell 13. As a result, the number of parts in the fuel cell cell 13 can be reduced.

[0097] <Ninth Embodiment> (First Embodiment) Next, the ninth embodiment will be described in detail with reference to the drawings.

[0098] [About the composition of porous materials] This embodiment differs from the seventh embodiment in terms of the configuration of the porous body 19. Figure 18 shows a perspective view of one porous body 19 according to this embodiment.

[0099] As shown in Figure 18, in this embodiment, unlike the seventh embodiment, the porous body 19 has a porous outermost end 19j formed outside the non-porous end 19h in the short direction Z of the porous body 19, and a porous outermost end 19k formed outside the non-porous end 19i.

[0100] Figure 19 shows an enlarged cross-sectional view of the contact area between the fuel cell cell 13 and the porous body 19 that is in contact with both sides thereof, according to this embodiment. In this embodiment, the outermost ends 19j and 19k of the porous body 19 are in contact with adjacent fuel cell cells 13, so these porous outermost ends 19j and 19k function as a gas diffusion layer for the fuel cell cell 13. Furthermore, the ends 19h and 19i following each outermost end 19j and 19k do not have pores, so these ends 19h and 19i function as separators for the fuel cell cell 13.

[0101] [Regarding the operation and effects of FC stacks] According to the configuration of the FC stack 11 in this embodiment, unlike the eighth embodiment, the non-porous ends 19h and 19i can function as separators, and the outermost ends 19j and 19k with pores can function as gas diffusion layers. Therefore, as shown in Figure 19, the separators and gas diffusion layers can be omitted from the fuel cell cell 13. As a result, the number of parts in the fuel cell cell 13 can be reduced.

[0102] In this embodiment as well, the porous body 19 is configured as described above near the contact portion with the fuel cell cell 13 in the same configuration as in the first embodiment, but a similar configuration may be added to the configurations of the second to sixth embodiments.

[0103] <Another embodiment> Furthermore, this disclosed technology is not limited to the embodiments described above, and it may be implemented by appropriately modifying some parts of the configuration without departing from the spirit of the disclosed technology.

[0104] (1) In each of the above embodiments, multiple through holes 20 are arranged in a row along the longitudinal direction X of the porous body 19, but they can also be arranged in a staggered pattern or randomly along the longitudinal direction X.

[0105] (2) In each of the above embodiments, the fuel cell system 1 is implemented in an electric vehicle, but the fuel cell system can also be implemented in a vehicle other than an electric vehicle. [Industrial applicability]

[0106] This disclosed technology can be used, for example, in fuel cell systems installed in electric vehicles. [Explanation of Symbols]

[0107] 1. Fuel cell system 11 FC Stack (Fuel Cell) 13 fuel cell cells 20 Through holes Y Direction of coolant flow X Longitudinal direction Z Short direction IV interval

Claims

1. In a fuel cell in which multiple fuel cell cells are stacked and a porous body constituting a channel through which a cooling medium flows is arranged between adjacent fuel cell cells, The porous body comprises a plurality of through holes that penetrate in the direction through which the cooling medium flows. A fuel cell characterized by the following features.

2. In the fuel cell according to claim 1, The multiple through holes are spaced apart along the longitudinal direction of the porous body in a direction perpendicular to the direction in which the cooling medium flows, The aforementioned interval differs between the middle and both ends in the longitudinal direction. A fuel cell characterized by the following features.

3. In the fuel cell according to claim 2, The aforementioned spacing is narrowest in the middle section along the longitudinal direction. A fuel cell characterized by the following features.

4. In the fuel cell according to claim 1, The multiple through holes are spaced apart along the longitudinal direction of the porous body in a direction perpendicular to the direction in which the cooling medium flows, The cross-sectional area of ​​the through hole differs between the middle and both ends in the longitudinal direction. A fuel cell characterized by the following features.

5. In the fuel cell according to claim 4, The cross-sectional area of ​​the through hole is largest in the middle section along the longitudinal direction. A fuel cell characterized by the following features.

6. In the fuel cell according to claim 1, The porous body is formed from a single material, The porosity of the porous material differs between the middle and both ends in the longitudinal direction of the porous material in a direction perpendicular to the direction in which the cooling medium flows. A fuel cell characterized by the following features.

7. In the fuel cell according to claim 6, The porosity of the porous material is highest in the middle portion in the longitudinal direction. A fuel cell characterized by the following features.

8. In the fuel cell according to claim 1, The porous body is formed from a single material, The porosity of the porous material differs between the middle and both ends in the direction in which the cooling medium flows. A fuel cell characterized by the following features.

9. In the fuel cell according to claim 8, The porosity of the porous material is highest in the middle portion in the direction in which the cooling medium flows. A fuel cell characterized by the following features.

10. In a fuel cell according to any one of claims 1 to 9, The porosity of the porous material is 0 near the point where the porous material is in contact with adjacent fuel cell cells. A fuel cell characterized by the following features.

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