Separator for fuel cells
The separators with differently sized protrusions at the corners ensure easy separation of stacked fuel cell components by creating a gap between overlapping grooves, addressing the handling difficulty in fuel cell manufacturing.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-25
AI Technical Summary
The challenge in fuel cell manufacturing is the difficulty in separating stacked separators due to tightly attached gas flow channels, making it hard to pick up individual separators from a stack.
The separators are designed with first and second protrusions of different heights at the corners, ensuring a gap between overlapping gas flow channel grooves when stacked, allowing easy separation by providing a non-overlapping contact point for protrusions.
This design facilitates easy separation of lower separators when lifting the top separator, maintaining efficient stacking during manufacturing by preventing overlapping protrusions and allowing air to enter the gap, thus simplifying the handling process.
Smart Images
Figure 2026085320000001_ABST
Abstract
Description
Technical Field
[0001] The technology disclosed in this specification relates to separators for fuel cells.
Background Art
[0002] In a fuel cell, a separator is disposed between two adjacent Membrane Electrode Assemblies (MEA). Separators for fuel cells are often made of metal plates with a thickness of 1.0 mm or less. The separator is provided with gas flow channels through which oxygen (air) or hydrogen flows. In the manufacturing process of a fuel cell, a plurality of separators are stacked and prepared. The gas flow channels are formed by pressing a thin flat substrate. The gas flow channels are concave-shaped when viewed from one side of the substrate and convex-shaped when viewed from the opposite side. That is, a convex (concave) shape of the same size is formed on the back side of the concave (convex) shape on one side of the substrate. Therefore, when a plurality of separators are stacked, the gas flow channels of the upper and lower separators are tightly attached to each other, making it difficult to pick them up one by one.
[0003] Patent Document 1 discloses a technique in which when picking up the uppermost separator, air is sent between the second separator from the top and the uppermost separator to make it easier to lift only the uppermost separator.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] This specification provides a technique for making it easier to separate the lower separators when picking up the top separator from a stack of multiple separators, by modifying the shape of the separators. [Means for solving the problem]
[0006] The separator disclosed herein comprises a rectangular flat substrate, a gas flow channel groove provided in the substrate, a first projection provided at at least one of the four corners of the substrate, and a plurality of second projections provided in the substrate so as to surround the first projection. The first projection and the second projections are hollow inside. The first projection and the second projections are of different heights. The distance between each first projection and each second projection is smaller than the manufacturing tolerance of the width of the gas flow channel groove.
[0007] In the separators disclosed herein, when stacked, even if the gas flow channel grooves of the upper separator and the lower separator overlap, the first and second protrusions do not necessarily overlap. The first protrusion of the lower (upper) separator is likely to overlap with the second protrusion of the upper (lower) separator. The first and second protrusions are of different heights. When the taller protrusion of the lower separator overlaps with the shorter protrusion of the upper separator, a gap is secured between the gas flow channel grooves of the upper and lower separators. This prevents the lower separator from remaining stacked when the upper separator is picked up.
[0008] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]
[0009] [Figure 1] This is a plan view of the separator in the embodiment. [Figure 2] This is a cross-sectional view of the separator along line II-II in Figure 1. [Figure 3] This is a cross-section of two overlapping separators. [Figure 4] A cross-sectional view of two overlapping separators (second embodiment). [Modes for carrying out the invention]
[0010] (First Embodiment) The separator 10 of the first embodiment will be described with reference to the drawings. The separator 10 is a component placed between two adjacent membrane electrode assemblies (MEAs) in a fuel cell. Figure 1 shows a plan view of the separator 10. Figure 1 also shows an enlarged view of the lower right corner of the separator 10. Figure 2 is a cross-sectional view of the separator 10 cut along the line II-II in Figure 1.
[0011] The separator 10 is a thin metal plate provided with a gas flow channel groove 12 and two types of protrusions (first protrusion 13 and second protrusion 14). Hereafter, the first protrusion 13 and the second protrusion may be collectively referred to as protrusions 13 and 14.
[0012] In this specification, the metal plate that serves as the base material for the separator 10 is referred to as the substrate 11. The gas flow channel groove 12 and the protrusions 13 and 14 are made by press working. Therefore, the gas flow channel groove 12 is concave on one side of the substrate 11 and convex on the opposite side. Conversely, the protrusions 13 and 14 are convex on one side of the substrate 11 and concave on the opposite side. Consequently, the gas flow channel groove 12 becomes a depression, and the protrusions 13 and 14 become hollow dome shapes.
[0013] Gas flow channel grooves 12 are provided on both sides of the substrate 11, but the gas flow channel groove on the other side is omitted from the diagram. In a fuel cell stack, oxygen flows through the gas flow channel groove on one side of the separator 10, and hydrogen flows through the gas flow channel groove on the other side.
[0014] The substrate 11 is rectangular in plan view, and the protrusions 13 and 14 are located at two diagonal corners of the rectangular substrate 11. One first protrusion 13 and multiple second protrusions 14 are arranged at one corner of the substrate 11. As shown in the enlarged view of Figure 1, the multiple second protrusions 14 are arranged to surround the first protrusion 13. In this embodiment, eight second protrusions are arranged to surround the first protrusion 13. In other words, the first protrusion 13 is located in the center of the distribution of the multiple second protrusions.
[0015] Figure 2 is a cross-sectional view of separator 10 cut along the line II-II in Figure 1. In other words, Figure 2 shows a cross-section of the separator cut along a line that intersects the gas flow channel groove 12 and the first projection 13. Two separators are shown in Figure 2, and to distinguish them, one separator (the upper separator in Figure 2) is referred to as separator 10a, and the other separator (the lower separator in Figure 2) is referred to as separator 10b.
[0016] As shown in Figure 2, the first projection 13 is higher than the second projection 14. Furthermore, although gas flow channel grooves 12 are provided in both separators 10a and 10b, the width Wa of the gas flow channel groove 12 in separator 10a and the width Wb of the gas flow channel groove 12 in separator 10b are different. The difference Tr in the widths of the two gas flow channel grooves 12 is due to the manufacturing tolerance of the gas flow channel groove width. The distance Pt between the first projection 13 and the second projection 14 is smaller than the manufacturing tolerance Tr of the gas flow channel groove width.
[0017] The first projection 13 and the second projection 14 provide the following advantages. Figure 3 shows a diagram in which separators 10a and 10b overlap. Because there is a difference in the manufacturing tolerance Tr between the width of the gas flow channel grooves 12 of separators 10a and 10b, even if separators 10a and 10b are offset by a distance Pt in the Y direction of the coordinate system in the figure, the gas flow channel grooves 12 of separator 10a and 10b overlap. As shown in Figure 3, in this case, the first projection 13 of the lower separator 10b overlaps with the second projection 14 of the upper separator 10a. Since the first projection 13 is higher than the second projection 14, the overlap of the first projection 13 and the second projection 14 ensures a gap between the gas flow channel groove 12 of separator 10a and the gas flow channel groove 12 of separator 10b. In Figure 3, arrow A indicates the contact point between the lower first projection 13 and the upper second projection 14, and arrow B indicates the gap between the gas flow channel grooves 12 of the upper and lower separators 10a and 10b. The gas flow channel grooves 12 of the upper and lower separators 10a and 10b overlap when viewed from the direction normal to the substrate 11, but a gap is maintained between them. This gap makes it easier to separate the lower separator 10b when the upper separator 10a is picked up.
[0018] Even if separators 10a and 10b are offset by a distance Pt in the Y direction, the gas flow channel grooves 12 of the upper and lower separators 10a and 10b will overlap. When multiple separators 10 are stacked, there will be variations in the distance Pt in the Y direction of the separators 10, but since the gas flow channel grooves 12 of all separators 10 will overlap, stacking the above separators 10 is permissible in the fuel cell manufacturing process.
[0019] As described above, by providing the first protrusion 13 and the plurality of second protrusions on the substrate 11, when lifting the uppermost separator 10 from the stack of the stacked separators 10, the second separator 10 is likely to separate. Note that the plurality of second protrusions 14 are arranged so as to surround one first protrusion 13, and the first protrusion 13 is higher than the second protrusions. Also, the distance Pt between the first protrusion 13 and the second protrusion 14 is smaller than the manufacturing tolerance Tr of the width of the gas flow path groove 12. Due to this relationship, when the plurality of separators 10 are stacked, the gas flow path grooves overlap each other, but the first protrusions do not overlap each other, and the first protrusion 13 of the upper (lower) separator 10 can overlap with the second protrusion 14 of the lower (upper) separator 10. When the first protrusion 13 of the upper (lower) separator 10 overlaps with the second protrusion 14 of the lower (upper) separator 10, a gap is secured between the gas flow path grooves of the two separators 10. Since this gap is continuous with the space around the separator 10, air enters the gap from the surroundings when lifting the upper separator 10. As a result, when lifting the upper separator 10, the lower separator 10 is likely to separate.
[0020] Note that FIG. 3 shows the case where the two separators 10a and 10b are displaced in the Y direction of the coordinate system in the figure. The same advantages can be obtained even when the two separators 10a and 10b are displaced in the X direction of the coordinate system in the figure. The same advantages can be obtained regardless of the direction in which the two separators 10a and 10b are displaced within the XY plane of the coordinate system in the figure.
[0021] (Second Embodiment) FIG. 4 shows a cross-sectional view when two separators 110a and 110b of the second embodiment are overlapped. The second protrusions 114 are arranged around the first protrusion 113. Similar to the case of the separator 10 of the first embodiment, the plurality of second protrusions 114 are arranged so as to surround the first protrusion 113 within the plane of the substrate 11.
[0022] In the separators 110a and 110b of the second embodiment, the first protrusion 113 is lower than the second protrusion 114. Even in this case, when the upper separator 110a and the lower separator 110b are overlapped with a displacement of a distance Pt in the Y direction, the upper and lower gas flow path grooves 12 overlap, and a gap is secured between them (the portion indicated by the arrow B in FIG. 4). In this case, a gap is secured between the upper and lower gas flow path grooves 12 by contact of one second protrusion 114 of the lower separator 110b with the substrate 11 of the upper separator 110a (the portion of the arrow A in FIG. 4). That is, the first protrusion 13 (113) and the second protrusion 14 (114) only need to have different heights.
[0023] Points to note regarding the technology described in the embodiments will be described. In the separator 10 of the embodiment, a set of protrusions 13 and 14 is provided at two diagonal corners of the substrate 11. The protrusions 13 and 14 only need to be provided at at least one of the four corners of the substrate 11.
[0024] The arrangement of the second protrusions 14 and 114 is not limited to the arrangement of the embodiment. The plurality of second protrusions only need to be arranged so as to surround the first protrusion. However, preferably, four or more second protrusions surround the first protrusion and are arranged at equal intervals.
[0025] The width of the gas flow path groove 12 is approximately 0.5 [mm], and the manufacturing tolerance of the width is approximately 0.05 [mm]. The distance Pt between the first protrusion 13 and the second protrusion 14 only needs to be approximately 0.04 [mm] or less.
[0026] As described above, specific examples of the present invention have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Further, the technology illustrated in this specification or the drawings can achieve a plurality of objects simultaneously, and has technical utility by achieving one of those objects itself.
Explanation of Reference Numerals
[0027] 10, 10a, 10b, 110a, 110b: Separator 11: Substrate 12: Gas flow channel groove 13, 113: First projection 14, 114: Second projection
Claims
[Claim 1] It is a separator for fuel cells, A rectangular flat substrate, A gas flow channel groove provided in the substrate, A first projection is provided at at least one of the four corners of the substrate, A plurality of second protrusions are provided on the substrate so as to surround the first protrusion, It is equipped with, The first projection and the second projection are hollow inside, The first projection and the second projection are of different heights. The distance between the first projection and each of the second projections is smaller than the manufacturing tolerance of the width of the gas flow channel groove. Separator.