Fuel battery system
By optimizing cooling air flow rates within the fuel cell system, the design addresses uneven cooling distribution, preventing electrolyte membrane drying and maintaining performance.
Patent Information
- Application Number
- JP2023113091
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-07-10
- Publication Date
- 2025-01-23
AI Technical Summary
Existing fuel cell systems experience uneven cooling air distribution, leading to electrolyte membrane drying on the inlet side of the oxidant gas flow path, which results in performance deterioration.
The system employs a cooling fan and fan shroud design that ensures a higher flow rate of cooling air at the oxidant gas inlet side compared to the outlet side, aligning with the plane direction of the fuel cells to counteract drying and maintain humidity.
This design effectively prevents electrolyte membrane drying on the inlet side, thereby maintaining fuel cell performance and durability.
Smart Images
Figure 2025010837000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a fuel cell system. [Background technology]
[0002] A fuel cell stack, in which a plurality of fuel cells that generate electricity by the reaction between hydrogen fuel and oxidant gas are stacked in a predetermined stacking direction, generates heat during power generation and therefore needs to be cooled.
[0003] Patent Document 1 discloses an air-cooled fuel cell system in which a fuel cell stack is cooled with air (cooling air). [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2016-119298 A Summary of the Invention [Problem to be solved by the invention]
[0005] In many fuel cells, an oxidant gas flow path is provided to extend along a planar direction of the fuel cell that intersects with the stacking direction of the fuel cell. In the fuel cell, the electrolyte membrane is more likely to dry out at the inlet side of the flow path than at the outlet side, and therefore the performance is more likely to deteriorate.
[0006] The fuel cell system disclosed in Patent Document 1 merely supplies cooling air whose strength is not uniform in the stacking direction to the fuel cell stack, and does not take into consideration the flow of cooling air in the planar direction. Therefore, in the fuel cell system disclosed in Patent Document 1, the electrolyte membrane at the inlet side of the oxidant gas flow path of the fuel cell is likely to dry out, and performance may be easily degraded.
[0007] The present invention has been made in view of the above, and has an object to suppress the deterioration of fuel cell performance that accompanies drying of the electrolyte membrane of the fuel cell. [Means for solving the problem]
[0008] In order to solve the above problems, the fuel cell system of the present invention is a fuel cell system comprising a fuel cell stack in which a plurality of plate-shaped fuel cell cells that generate electricity by reacting hydrogen fuel with an oxidant gas are stacked in a predetermined stacking direction, and a cooling fan that flows cooling air to cool the fuel cell stack through the fuel cell stack, wherein the fuel cell has an oxidant gas flow path extending along a planar direction of the fuel cell cell that intersects the stacking direction, an oxidant gas inlet that allows the oxidant gas to flow into the oxidant gas flow path, and an oxidant gas outlet that allows the oxidant gas to flow out from the oxidant gas flow path, the flow direction of the cooling air flowing through the fuel cell stack is along the planar direction of the fuel cell cell and intersects the extension direction of the oxidant gas flow path, and the flow rate of the cooling air flowing through the fuel cell stack is greater on the oxidant gas inlet side than on the oxidant gas outlet side. Effect of the Invention
[0009] According to the present invention, it is possible to suppress the deterioration of fuel cell performance that is caused by drying of the electrolyte membrane of the fuel cell. [Brief description of the drawings]
[0010] [Figure 1] FIG. 2 is a top view illustrating the internal configuration of the fuel cell system according to the first embodiment. [Diagram 2] FIG. 2(a) is a top view of a fuel cell, and FIG. 2(b) is a cross-sectional view taken along the line AA of FIG. 2(a). [Diagram 3] FIG. 3(a) is a top view illustrating the internal configuration of a fuel cell system according to a second embodiment, and FIG. 3(b) is a top view illustrating the internal configuration of a fuel cell system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments, the same reference numerals denote the same configurations or functions, and unless otherwise specified, the description thereof will be omitted.
[0012] FIG. 1 is a top view illustrating the internal configuration of a fuel cell system 100 according to a first embodiment.
[0013] The fuel cell system 100 comprises a fuel cell stack 2 consisting of multiple plate-shaped fuel cell cells 21 stacked in a predetermined stacking direction, each of which generates electricity by reacting hydrogen fuel with an oxidant gas, a cooling fan 4 that circulates cooling air through the fuel cell stack 2 to cool the fuel cell stack 2, a fan shroud 3 that connects the fuel cell stack 2 and the cooling fan 4, auxiliary components 5 that operate the fuel cell stack 2, and a housing 1 that accommodates the fuel cell stack 2, the fan shroud 3, the cooling fan 4 and the auxiliary components 5.
[0014] The housing 1 houses the fuel cell stack 2, the fan shroud 3, the cooling fan 4, and the auxiliary components 5. The housing 1 has a substantially rectangular box shape. The housing 1 has a front wall 11 provided with an intake port 15 for drawing cooling air (F1) into the housing 1, a rear wall 12 provided with an exhaust port 16 for discharging cooling air (F5) to the outside of the housing 1 and facing the front wall 11, a left wall 13 continuous with the front wall 11 and the rear wall 12, a right wall 14 continuous with the front wall 11 and the rear wall 12 and facing the left wall 13, a bottom plate continuous with the front wall 11, the rear wall 12, the left wall 13, and the right wall 14, and a top plate continuous with the front wall 11, the rear wall 12, the left wall 13, and the right wall 14 and facing the bottom plate.
[0015] The fuel cell stack 2 is constructed by stacking a plurality of plate-shaped fuel cell cells 21 in a predetermined stacking direction. The stacking direction of the fuel cell cells 21 is from the back side of the paper surface of FIG. 1 to the front side of the paper surface. The fuel cell stack 2 has a cooling air inlet 6 that allows cooling air (F2) sucked into the housing 1 to flow into the fuel cell stack 2. The cooling air inlet 6 is provided in the wall on the intake port 15 side of the fuel cell stack 2. An opening is provided in the wall on the exhaust port 16 side of the fuel cell stack 2, and a cooling fan 4 is connected to the opening via a fan shroud 3.
[0016] The auxiliary parts 5 include, for example, an air compressor that supplies oxidant gas into the fuel cell stack 2, and an air cleaner connected upstream of the air compressor that removes foreign matter from the oxidant gas. The auxiliary parts 5 include a regulator that adjusts the amount of hydrogen fuel supplied from the hydrogen tank, and an injector connected downstream of the regulator that supplies hydrogen fuel into the fuel cell stack 2. The auxiliary parts 5 include a converter that increases or decreases the voltage of the power generated by the fuel cell stack 2, and an inverter that converts direct current to alternating current. The auxiliary parts 5 are arranged closer to the intake port 15 than the fuel cell stack 2.
[0017] The cooling fan 4 is disposed on the exhaust port 16 side of the fuel cell stack 2 via the fan shroud 3. That is, the cooling fan 4 is connected to the downstream side of the cooling air inlet 6 of the fuel cell stack 2 via the fan shroud 3. The intake port 15 side of the cooling fan 4 is connected to the fan shroud 3. The exhaust port 16 side of the cooling fan 4 is provided with a cooling air outlet 7 that allows the cooling air (F3, F4) flowing in the fuel cell stack 2 to flow out of the cooling fan 4. The flow direction of the cooling air is from the fuel cell stack 2 toward the cooling fan 4, along the planar direction of the fuel cell 21, and perpendicular to the stacking direction of the fuel cell 21. The flow direction of the cooling air is from the left side of the paper to the right side of the paper in FIG. 1.
[0018] When the cooling fan 4 rotates, cooling air (F1) is sucked into the housing 1 through the intake port 15 and passes through the auxiliary components 5. The cooling air (F2) that has passed through the auxiliary components 5 flows into the fuel cell stack 2 through the cooling air inlet 6. The cooling air (F3, F4) in the fuel cell stack 2 passes through the cooling fins, fan shroud 3 and cooling fan 4 in the fuel cell stack 2 and flows out from the cooling air outlet 7. The cooling air (F5) that flows out from the cooling air outlet 7 is exhausted to the outside of the housing 1 through the exhaust port 16.
[0019] Fig. 2(a) is a top view of the fuel cell 21. Fig. 2(b) is a cross-sectional view taken along line AA of Fig. 2(a).
[0020] 2(b), the fuel cell 21 includes an electrolyte membrane 91, catalyst layers (electrodes) 92, 93, diffusion layers 94, 95, a cathode separator 96, and an anode separator 97. The fuel cell 21 is configured such that the catalyst layers (electrodes) 92, 93 are disposed on both sides of the electrolyte membrane 91, the diffusion layers 94, 95 are disposed on the outer surfaces of the catalyst layers (electrodes) 92, 93, and the cathode separator 96 and the anode separator 97 are disposed on the outer surfaces of the diffusion layers 94, 95, respectively. Flow paths through which oxidant gas and hydrogen fuel can flow are formed on the sides of the cathode separator 96 and the anode separator 97 that contact the diffusion layers 94, 95, respectively.
[0021] FIG. 2(a) shows the oxidant gas flow path 25 formed in the cathode separator 96. The fuel cell 21 has an oxidant gas flow path 25 extending along the planar direction of the fuel cell intersecting the stacking direction, an oxidant gas inlet 23 for making the oxidant gas flow into the oxidant gas flow path 25, and an oxidant gas outlet 24 for making the oxidant gas flow out from the oxidant gas flow path 25. The oxidant gas flowing in from the oxidant gas inlet 23 is supplied to the power generation surface 22 of the fuel cell 21 through the oxidant gas flow path 25, and flows out from the oxidant gas outlet 24 through the oxidant gas flow path 25. The oxidant gas flow path 25 extends from the upper side to the lower side of the paper in FIG. 2(a). The cooling air (F3, F4) flows from the left side to the right side of the paper in FIG. 2(a). That is, the flow direction of the cooling air (F3, F4) flowing through the fuel cell stack 2 is along the planar direction of the fuel cells 21 and intersects with the direction in which the oxidizing gas flow field 25 extends.
[0022] The fuel cell 21 also has a hydrogen fuel inlet 26 that allows hydrogen fuel to flow into a hydrogen fuel flow passage formed in the anode separator 97, and a hydrogen fuel outlet 27 that allows hydrogen fuel to flow out from the hydrogen fuel flow passage.
[0023] Here, dry oxidant gas is supplied from outside the fuel cell 21 to the oxidant gas inlet 23 side of the fuel cell 21, whereas oxidant gas containing a large amount of water produced by power generation on the power generation surface 22 flows on the oxidant gas outlet 24 side of the fuel cell 21. Therefore, the amount of water in the oxidant gas is less on the oxidant gas inlet 23 side of the fuel cell 21 than on the oxidant gas outlet 24 side, and the electrolyte membrane 91 is more likely to dry out. As a result, the performance as a fuel cell, such as power generation performance and durability, is more likely to deteriorate on the oxidant gas inlet 23 side of the fuel cell 21 than on the oxidant gas outlet 24 side.
[0024] Therefore, in the fuel cell system 100, the flow rate of the cooling air (F3, F4) flowing through the fuel cell stack 2 is set to be greater on the oxidant gas inlet 23 side (flow rate of the cooling air F3) than on the oxidant gas outlet 24 side (flow rate of the cooling air F4). This allows the fuel cell 21 to lower the temperature on the oxidant gas inlet 23 side than on the oxidant gas outlet 24 side even if the amount of moisture in the oxidant gas on the oxidant gas inlet 23 side is reduced. As a result, the fuel cell 21 can suppress a decrease in relative humidity on the oxidant gas inlet 23 side, and can suppress drying of the electrolyte membrane 91 on the oxidant gas inlet 23 side. Therefore, the fuel cell system 100 can suppress a decrease in performance as a fuel cell caused by drying of the electrolyte membrane 91 of the fuel cell 21.
[0025] 1, in the fuel cell system 100 of the first embodiment, the shape of the fan shroud 3 is asymmetric with respect to a plane P that passes through the center of the fuel cell stack 2 and is aligned along both the flow direction of the cooling air and the stacking direction of the fuel cell units 21. Furthermore, in the fuel cell system 100 of the first embodiment, the cooling fan 4 is disposed such that the rotation axis of the cooling fan 4 is offset toward the oxidant gas inlet 23 with respect to the plane P.
[0026] As a result, the fuel cell system 100 of the first embodiment can make the flow rate of the cooling air flowing through the fuel cell stack 2 on the oxidant gas inlet 23 side greater than the flow rate on the oxidant gas outlet 24 side. Therefore, the fuel cell system 100 of the first embodiment can reduce the temperature on the oxidant gas inlet 23 side to suppress a decrease in relative humidity, thereby suppressing drying of the electrolyte membrane 91 on the oxidant gas inlet 23 side. Therefore, the fuel cell system 100 of the first embodiment can suppress a decrease in fuel cell performance due to drying of the electrolyte membrane 91.
[0027] The plane P is a plane that passes through the middle between the oxidant gas inlet 23 and the oxidant gas outlet 24 in a direction (the up-down direction on the page of FIG. 1) perpendicular to the flow direction of the cooling air and the stacking direction of the fuel cell units 21. The distance from the oxidant gas inlet 23 to the plane P and the distance from the oxidant gas outlet 24 to the plane P are approximately equal.
[0028] Fig. 3(a) is a top view illustrating the internal configuration of a fuel cell system 100 according to a second embodiment. Fig. 3(b) is a top view illustrating the internal configuration of a fuel cell system 100 according to a third embodiment.
[0029] 3(a), in the fuel cell system 100 of the second embodiment, the cooling fan 4 is disposed so that the rotation axis of the cooling fan 4 is positioned on the plane P without being offset toward the oxidant gas inlet 23 side with respect to the plane P. However, in the fuel cell system 100 of the second embodiment, the shape of the fan shroud 3 is asymmetric with respect to the plane P. Specifically, the fan shroud 3 of the second embodiment is formed in a bulging shape with the oxidant gas inlet 23 side away from the plane P, and is formed in a narrowing shape with the oxidant gas outlet 24 side approaching the plane P.
[0030] As a result, in the fuel cell system 100 of the second embodiment, similar to the first embodiment, the flow rate of the cooling air on the oxidant gas inlet 23 side can be made greater than the flow rate of the cooling air on the oxidant gas outlet 24 side. Therefore, in the fuel cell system 100 of the second embodiment, similar to the first embodiment, drying of the electrolyte membrane 91 on the oxidant gas inlet 23 side can be suppressed, and thus deterioration of the fuel cell performance due to drying of the electrolyte membrane 91 can be suppressed.
[0031] 3(b), in the fuel cell system 100 of the third embodiment, the shape of the fan shroud 3 is symmetrical with respect to the plane P, and the cooling fan 4 is arranged so that the rotation axis of the cooling fan 4 is also located on the plane P. However, in the fuel cell system 100 of the third embodiment, the auxiliary parts 5 are arranged so that the occupied space of the auxiliary parts 5 occupying the oxidant gas outlet 24 side of the plane P is larger than the occupied space of the auxiliary parts 5 occupying the oxidant gas inlet 23 side.
[0032] As a result, in the fuel cell system 100 of the third embodiment, similar to the first and second embodiments, the flow rate of the cooling air on the oxidant gas inlet 23 side can be made greater than the flow rate of the cooling air on the oxidant gas outlet 24 side. Therefore, in the fuel cell system 100 of the third embodiment, similar to the first and second embodiments, drying of the electrolyte membrane 91 on the oxidant gas inlet 23 side can be suppressed, and thus deterioration of the fuel cell performance due to drying of the electrolyte membrane 91 can be suppressed.
[0033] The fuel cell system 100 may combine the respective features of the first to third embodiments, thereby making it possible for the fuel cell system 100 to enhance the effect of suppressing the deterioration of the performance of the fuel cell due to the drying of the electrolyte membrane 91.
[0034] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the present invention. In the present invention, the configuration of one embodiment can be added to the configuration of another embodiment, the configuration of one embodiment can be replaced with the configuration of another embodiment, or a part of the configuration of one embodiment can be deleted. [Explanation of symbols]
[0035] 1...housing, 2...fuel cell stack, 3...fan shroud, 4...cooling fan, 5...auxiliary parts, 6...cooling air inlet, 7...cooling air outlet, 8...oxidant gas flow direction, 11...front wall, 12...rear wall, 13...left wall, 14...right wall, 15...air intake, 16...exhaust port, 21...fuel cell, 22...power generation surface, 23...oxidant gas inlet, 24...oxidant gas outlet, 25...oxidant gas flow path, 26...hydrogen fuel inlet, 27...hydrogen fuel outlet, 91...electrolyte membrane, 92, 93...catalyst layer (electrode), 94, 95...diffusion layer, 96...cathode separator, 97...anode separator, 100...fuel cell system
Claims
[Claim 1] a fuel cell stack in which a plurality of plate-shaped fuel cells that generate electricity by a reaction between hydrogen fuel and an oxidant gas are stacked in a predetermined stacking direction; a cooling fan that supplies cooling air to the fuel cell stack to cool the fuel cell stack, the fuel cell has an oxidant gas flow path extending along a planar direction of the fuel cell intersecting the stacking direction, an oxidant gas inlet for causing the oxidant gas to flow into the oxidant gas flow path, and an oxidant gas outlet for causing the oxidant gas to flow out from the oxidant gas flow path, a flow direction of the cooling air flowing through the fuel cell stack is aligned with a planar direction of the fuel cell unit and intersects with a direction in which the oxidizing gas flow field extends, The flow rate of the cooling air flowing through the fuel cell stack is greater on the oxidant gas inlet side than on the oxidant gas outlet side. A fuel cell system comprising:
Citation Information
Patent Citations
Fuel cell module, and method for operating fuel cell module
JP2016119298A