fuel cell
The fuel cell design addresses water accumulation issues in throttle portions by limiting throttling section areas to 15% or less, thereby maintaining power generation efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-08
- Publication Date
- 2026-05-20
AI Technical Summary
The accumulation of water in throttle portions of fuel cell gas flow paths can lead to blockages, increasing resistance differences and deteriorating power generation performance.
A fuel cell design with a cathode-side separator groove portion that limits the flow path cross-sectional area of throttling sections to 15% or less of normal sections, reducing gas flow resistance disparities when blockages occur.
This design suppresses a decrease in power generation performance by minimizing gas flow resistance differences between blocked and unblocked flow paths.
Smart Images
Figure 2026083896000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a fuel cell.
Background Art
[0002] A fuel cell is known in which a throttle portion is provided in an anode gas flow path or a cathode gas flow path (see Patent Document 1). The flow path cross-sectional area of the throttle portion is smaller than the flow path cross-sectional area of other portions of the anode gas flow path or the cathode gas flow path.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] There is a risk that generated water will accumulate in the throttle portion and the flow path will be blocked. In this case, there is a problem that the resistance difference in the gas flow between the blocked flow path and the unblocked flow path increases, and the power generation performance deteriorates.
Means for Solving the Problems
[0005] The present disclosure has been made to solve the above-described problems and can be realized in the following forms.
[0006] According to an aspect of the present disclosure, a fuel cell is provided. The fuel cell includes a membrane electrode assembly, a power generation body having a cathode-side surface and an anode-side surface, and a pair of separators including a cathode-side separator and an anode-side separator that sandwich the power generation body. The cathode-side separator has a groove portion that forms a cathode gas flow path between the cathode-side surface, and the groove portion has a throttle portion. The flow path cross-sectional area of the throttle portion is 15% or less of the flow path cross-sectional area of a portion of the cathode gas flow path that is not the throttle portion. In this type of fuel cell, since the flow path cross-sectional area of the throttled section is 15 percent or less of the flow path cross-sectional area of the other sections, even if the cathode gas flow path is blocked, the difference in gas flow resistance between the blocked and unblocked cathode gas flow paths can be reduced compared to the case where the flow path cross-sectional area of the throttled section is greater than 15 percent of the flow path cross-sectional area of the other sections. Therefore, a decrease in power generation performance can be suppressed.
[0007] Furthermore, this disclosure can be implemented in various forms, for example, as a separator for fuel cell cells, a fuel cell stack comprising multiple stacked fuel cell cells, or a method for manufacturing fuel cell cells. [Brief explanation of the drawing]
[0008] [Figure 1] This is an explanatory diagram showing a disassembled fuel cell. [Figure 2] This is a cross-sectional view obtained by cutting along the line II-II in Figure 1. [Modes for carrying out the invention]
[0009] A. First Embodiment: Figure 1 is an explanatory diagram showing an exploded view of a fuel cell cell 100 in one embodiment of the present disclosure. The fuel cell cell 100 is a polymer electrolyte fuel cell that generates electricity by receiving hydrogen as the cathode gas and oxygen as the anode gas as reaction gases. The fuel cell cell 100 comprises a power generation unit 10, a resin frame 20, a pair of separators 30 and 40, and a manifold hole 50.
[0010] The power generator 10 comprises an electrolyte membrane (not shown), catalyst layers (not shown) formed adjacent to both sides of the electrolyte membrane, and a gas diffusion layer (not shown) formed adjacent to one side of the catalyst layer. The electrolyte membrane is a solid polymer thin film that exhibits good proton conductivity in a wet state. The electrolyte membrane is composed of, for example, an ion exchange membrane made of a fluororesin. The catalyst layer comprises a catalyst that promotes the chemical reaction between hydrogen and oxygen, and carbon particles supporting the catalyst. The electrolyte membrane and catalyst layer together are also called a membrane electrode assembly (MEA).
[0011] The gas diffusion layer is provided adjacent to one of the catalyst layers. The gas diffusion layer diffuses the reaction gas used in the electrode reaction along the plane of the electrolyte membrane and is composed of a porous diffusion layer substrate. As the diffusion layer substrate, porous substrates with conductivity and gas diffusion properties such as carbon fiber substrates, graphite fiber substrates, and foamed metals are used. This electrolyte membrane, catalyst layer, and gas diffusion layer together are also called a membrane electrode gas diffusion layer assembly (MEGA).
[0012] The resin frame 20 is a frame-shaped resin sheet member having a hole 21 in the center. In this embodiment, polyethylene terephthalate (PET) is used for the resin frame 20. However, various other thermoplastic resin members such as polypropylene and polyethylene may be used as the resin member. The power generation element 10 is placed in the hole 21 of the resin frame 20. The bonded structure of the power generation element 10 and the gas diffusion layer provided on the other side of the power generation element 10 (the side with the catalyst layer) to the resin frame 20 is also called a bonded structure.
[0013] The pair of separators 30 and 40 are members that sandwich the power generator 10. More specifically, the cathode-side separator 30 is positioned adjacent to the cathode-side surface of the power generator 10. The anode-side separator 40 is positioned adjacent to the anode-side surface of the power generator 10. The separators 30 and 40 are formed, for example, by press molding a metal plate made of stainless steel, titanium, or an alloy thereof.
[0014] The cathode-side separator 30 has a groove 31. The groove 31 is a portion that forms a cathode gas flow path between the cathode-side separator 30 and the cathode-side surface of the power generator 10 by sandwiching the anode-side separator 40 and the power generator 10. The groove 31 has a plurality of throttling portions 31a and normal portions 31b. The throttling portions 31a are portions that limit the flow rate of the cathode gas passing through. The normal portions 31b are portions of the cathode gas flow path that are not throttling portions 31a. Details of the throttling portions 31a will be described later.
[0015] The resin frame 20 and the separators 30 and 40 have manifold holes 50. The manifold holes 50 connect the resin frame 20 and the separators 30 and 40, through which reaction gas or cooling water flows.
[0016] Figure 2 is a schematic cross-sectional view of the cathode gas flow path in Figure 1, taken along the II-II line. More specifically, Figure 2 is a cross-sectional view of the cathode gas flow path in Figure 1, taken along a direction perpendicular to the gas flow direction. The flow path cross-sectional area S1 of the throttling section 31a is 15 percent or less of the flow path cross-sectional area S2 of the normal section 31b. In this embodiment, the width of the throttling section 31a is smaller than the width of the normal section 31b. Also, the height of the throttling section 31a is smaller than the height of the normal section 31b.
[0017] In this embodiment, since the flow path cross-sectional area S1 of the throttle portion 31a is 15% or less of the flow path cross-sectional area S2 of the normal portion 31b that is not the throttle portion 31a, compared with the case where the flow path cross-sectional area S1 of the throttle portion 31a is larger than 15% of the flow path cross-sectional area S2 of the normal portion 31b, even if the cathode gas flow path is blocked, the resistance difference in the gas flow between the unblocked cathode gas flow path can be reduced. Therefore, it is possible to suppress a decrease in power generation performance.
[0018] B. Other Embodiments: (B1) In the above-described embodiment, the groove portion 31 has a plurality of throttle portions 31a. However, the groove portion 31 may have only one throttle portion 31a.
[0019] (B2) In the above-described embodiment, the anode-side separator 40 may also have a throttle portion. More specifically, by sandwiching the power generation body 10 between the cathode-side separator 30 and the anode-side separator 40, the groove portion of the anode-side separator 40 that forms an anode gas flow path between the anode-side separator 40 and the anode-side surface of the power generation body 10 may have a throttle portion.
[0020] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.
Description of Reference Numerals
[0021] 10... Power generation body, 20... Resin frame, 21... Hole portion, 30... Cathode-side separator, 31... Groove portion, 31a... Throttle portion, 31b... Normal portion, 40... Anode-side separator, 50... Manifold hole, 100... Fuel cell
Claims
[Claim 1] It is a fuel cell cell, A power generator comprising a film electrode assembly and having a cathode-side surface and an anode-side surface, The system comprises a pair of separators, one having a cathode-side separator and the other an anode-side separator, which sandwich the power generation unit. The cathode-side separator has a groove that forms a cathode gas flow path between itself and the cathode-side surface, and has a groove with a constricted portion. A fuel cell in which the flow path cross-sectional area of the throttled portion is 15 percent or less of the flow path cross-sectional area of the portion of the cathode gas flow path that is not the throttled portion.