Electrochemical cell unit with improved separator plate

Abstract

Electrochemical cell units (400) and stacks comprising a separator plate (410) overlying a cell layer (405), the separator plate (410) having a selectively shaped three-dimensional (3D) region overlying at least a portion of the electrochemically active cell area (307), the separator plate (410) being modified in the three-dimensional (3D) region into a first plurality of outwardly extending dimple-like projections (430, 433) that define a height of a first fluid volume (415) on a first side of the separator plate (410) and a second plurality of outwardly extending dimple-like projections (435, 438) that define a height of a second fluid volume on a second side of the separator plate (410). An intermediate planar region (443) is disposed between the protrusions (430, 433, 435), and the intermediate planar region (443) is shaped to selectively vary its height in at least one direction across the active cell area (307) such that the respective heights of the first fluid volume (415) and the second fluid volume relative to one another correspondingly increase and decrease.

Description

Technical Field

[0001] The present invention relates to electrochemical cell units, in particular fuel cell units and electrolysis cell units, stacks comprising such cell units, methods of manufacturing separator plates for use in such cell units, separator plates formed as such, and uses of such cell units. The cell units of the present invention include solid oxide type, polymer electrolyte membrane type, and molten carbonate type cells. The present invention more specifically relates to solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) units, which may include metal-supported solid oxide fuel cell (MS-SOFC) or electrolysis cell (MS-SOEC) units. Background Art

[0002] Some fuel cell units can generate electricity by using an electrochemical conversion process that oxidizes fuel to produce electricity. Some fuel cell units can also, or alternatively, operate as regenerative fuel cell (or reversible fuel cell) units, often known as electrolyser-type fuel cell units, for example to separate hydrogen and oxygen from water, or to separate carbon monoxide and oxygen from carbon dioxide. They may be tubular or planar. Planar fuel cell units may be arranged one on top of another in a stack configuration, for example 100 to 200 fuel cell units in a stack, with the individual fuel cell units being arranged, for example, electrically in series.

[0003] Solid oxide fuel cell (SOFC) units that generate electricity are based on a solid oxide electrolyte that conducts negative oxygen ions from the cathode, located on the opposite side of the electrolyte, to the anode. Thus, the fuel or reformed fuel is in contact with the anode (fuel electrode), and an oxidizer, such as air or an oxygen-rich fluid, is in contact with the cathode (air electrode). Conventional ceramic-supported (e.g., anode-supported) SOFCs have low mechanical strength and are prone to breakage. Therefore, metal-supported SOFCs have been developed that have an active fuel cell component layer supported on a metal substrate. In these cells, the ceramic layer performs only electrochemical functions and can be made very thin; that is, the ceramic layer is not self-supporting but rather a thin coating / film laid on and supported by the metal substrate. Such metal-supported SOFC stacks are more robust, less expensive, have superior thermal properties, and can be manufactured using conventional metal welding techniques compared to ceramic-supported SOFCs.

[0004] Solid oxide electrolytic cells (SOECs) may have the same structure as SOFCs, but they essentially operate SOFCs in reverse or regenerative mode, using electrical energy input to achieve electrolysis of water and / or carbon dioxide, and using a solid oxide electrolyte to produce hydrogen gas and / or carbon monoxide and oxygen.

[0005] This invention relates to electrochemical cell units and the design of their separator plates. Therefore, it is applicable to various types of fuel cells and electrolytic cells, for example, based on solid oxide electrolytes, polymer electrolyte membranes, and fused electrolytes. For convenience, the term "cell unit" is used to refer to an "electrochemical cell unit" including a fuel cell or electrolytic cell unit.

[0006] Each cell unit in a stack of cell units typically contains a cell layer comprising an electrochemically active cell region (such as a metal-supported electrochemically active cell region) and a separator plate. The separator plate typically contacts one side of the cell layer of its cell unit and may also contact the opposite side of the cell layer of an adjacent cell unit in the stack of cell units.

[0007] Figure 1 is quoted from WO 2020 / 126486 A1. Figure 1 shows an exploded view of the fuel cell unit 10 and two gaskets 34. The fuel cell unit 10 comprises a flat metal support plate 14 stacked adjacent to a separator plate 12. The separator plate 12 is shown to have a flanged peripheral feature 18 around its periphery. The flanged peripheral feature 18 extends from the main plane of the sheet, as seen in the central fluid volume area, to form a fluid volume 20 within the fuel cell unit during assembly. In the middle portion of the fuel cell unit 10, an electrochemically active cell region 50 (i.e., including the electrochemically active layer) is provided on the metal support plate located outside the fluid volume 20. The metal support plate 14 is provided with a number of small holes (not shown) so that the fluid in the fluid volume 20 can come into contact with the side of the electrochemical layer closest to the metal support plate 14. The anode (fuel electrode) layer may be located adjacent to a small pore in the fuel cell unit containing a fuel flow volume 20 supplied by the inflow and outflow of fuel through the fluid port 22. The cathode (air electrode) layer may be located on the opposite side of the electrochemically active cell region 50, i.e., its outer surface, and is exposed to air flowing across its layer during use of the fuel cell unit 10. Fluid ports 22 are provided on both the separator plate 12 and the metal support plate 14. Around the fluid ports of the separator plate 12, circular dimples 24 are provided extending from the base plane of the fluid volume 20 for a distance corresponding to the height of the flanged peripheral feature 18. This is to ensure that, when the cell unit 10 is assembled, it makes contact with the opposing surface of the metal support plate 14, as well as the flanged peripheral feature 18. The central projection 32 and the central lower projection 30 create electrical contact between the cell units and also provide support to the fuel cell unit in the central region, extending upward to the lower surface of the metal support plate 14 in the region of small holes and downward to the opposing surface of the electrochemically active layer of the cell below. The separator plate 12 between the central projection 32 and the central lower projection 30 forms an intermediate plane, which is at the same height across the (opposite) areas of the electrochemically active cell region 50.

[0008] In configuration WO 2020 / 126486 A1, the dimples allow the fluid within the fluid volume 20 to mix throughout the entire fluid volume 20. However, since these do not control the distribution of the fluid within the fluid volume 20, the distribution of the fluid within the fluid volume 20 may not be optimal.

[0009] Figure 2 is quoted from US2014 / 065508 A1. Figure 2 (left) is a plan view showing a portion of the interconnect (or separator) 9, and Figure 2 (right) schematically shows a cross-section of the interconnect 9 viewed along line C-C210. ​​The peripheral seal 215 seals the anode side of the interconnect 9 and adjacent fuel cells to prevent air from reaching the anode electrode of the fuel cell. The fuel distribution flow field 219 includes regions 1 (251), 2 (253), and 3 (255) of varying depths within region 205 to provide varying degrees of flow restriction to the fuel entering through port 216a. A channel 208 is provided in the flow field 211 of region 209. The first region 251 has the greatest depth and guides the fuel from port 216a across area 231 to the channel 208 at the periphery of the flow field 211. The second region 253 has an intermediate depth and guides fuel from port 216a across area 231 to channel 208 between the periphery and the middle portion of the flow field 211. The third region 255 has the shallowest depth and guides fuel from port 216a across area 231 to channel 208 in the central portion of the flow field 211. Rib 213 is concentric with port 216a. The depth variations between the different regions 251, 253, and 255 are formed by powder metallurgy. The depth variations between the different regions 251, 253, and 255 can change the degree of flow restriction between the regions. The electrochemically active layer of the cell unit is located within the plan view area of ​​the flow field 211. The height of each channel 208 is the same.

[0010] In the US2014 / 065508 A1 configuration, channels confine (separate) the fuel there, thereby preventing flow across a separator perpendicular to the channel. Fluids in separate channels cannot mix. The manifold must distribute the fuel to various channels, which then duct the fuel across the area of ​​the cell unit covered with the electrochemically active layer. Thus, the channels can distribute the fuel across the entire area of ​​the cell unit covered with the electrochemically active layer. The depth variations between the different regions 251, 253, and 255 of the manifold are formed by powder metallurgy, an expensive technique. Blockage of individual channels can lead to a fuel shortage in the electrochemically active area supplied by that channel. This can damage the electrochemically active area and cause cell unit failure. The contact areas of the channels are in contact with the electrochemically active layer, and these contact areas reduce the area of ​​the outermost layer of the electrochemically active layer that is in fluid communication with the fuel volume. As a result, the power generated in these areas decreases, and the power density of the cell unit may decrease accordingly.

[0011] This invention attempts to address, overcome, or mitigate at least one of the drawbacks of the prior art. [Overview of the Initiative]

[0012] In the first embodiment, an electrochemical cell unit is provided. A cell layer containing an electrochemically active cell region, It includes a separator plate containing a metal sheet covering the cell layer, The separator plate has a selectively molded three-dimensional (3D) region that covers at least a portion of the electrochemically active cell region. In that three-dimensional (3D) domain, The metal sheet is deformed into a first plurality of outwardly extending dimple-like protrusions that define the height of the first fluid volume on the first side of the separator plate. In addition, the metal sheet is deformed into a second plurality of outwardly extending dimple-like protrusions that define the height of the second fluid volume on the second side of the separator plate. As a result, the intermediate planar region is positioned between the protrusions. The intermediate planar region is formed such that its height is selectively varied in at least one direction across the active cell region such that the relative heights of the first and second fluid volumes increase and decrease in corresponding terms.

[0013] The intermediate planar region is typically part of the sheet between dimple-like protrusions. The change in height may be a (continuous) curved surface, a linear (flat) inclined surface (e.g., inclined with respect to the cell layer), or a step-like structure with flat (or curved) surfaces between steps.

[0014] In contrast to conventional techniques where the intermediate planar region between dimple-like protrusions is of constant height, the height of the intermediate planar region can be selectively adjusted / modified in at least one direction across the active cell region. Thus, the height of the first and / or second fluid volume increases and / or decreases accordingly. If the height of a portion of the fluid volume increases due to the change in the height of the intermediate planar region, the fluid flow rate in that portion will be relatively higher than the fluid flow rate in the portion of the fluid volume that is lower (in other words, the higher the height of that portion of the fluid volume, the higher the fluid flow rate in that portion of the fluid volume). Consequently, the change in the height of the intermediate planar region can be used to guide fluid into the first and / or second fluid volume. Since the intermediate planar region overlaps with (and faces) the electrochemically active cell region, the change in the intermediate plane can be used to guide (i.e., distribute more evenly) fluid over a range of the electrochemically active cell region, thereby improving the performance of the cell unit. This can be achieved without requiring channels in the active cell region to guide the fluid (preferably, the 3D region contains no channels), eliminating the need for a fluid distribution region or manifold within each cell unit. As a result, the electrochemically active cell region can occupy a large portion of the cell unit area, thereby improving the power density (in the case of fuel cell operation) or hydrogen production rate (in the case of electrolytic cell operation) of each cell unit.

[0015] Since the separator plate is formed by shaping (deforming) a metal sheet, dimple-like protrusions on the first side of the separator plate appear as dimple-like cavities on the second side of the separator plate, and similarly for any other features formed therein. This link may be perceived as a disadvantage from a design standpoint in that it results in a loss of degrees of freedom. However, the shaping process for forming the metal sheet can be used economically to produce electrochemical cells on a large scale, and at the same time, the link can also be used to adjust the balance between the first and second fluid volumes, respectively, to achieve improved technical performance, taking into account port configuration, flow paths and directions, as well as the thermal profile in the cell in question. For example, in an SOFC, if the height of the midplane is such that the height of the fuel volume decreases toward the center of the cell unit, then the oxidizer volume increases accordingly toward the center of the cell unit, thereby increasing the flow rate of oxidizer across the center of the cell unit. The oxidizer may be used to cool the cell unit, and the center of the cell unit is usually the hottest part of the cell unit. Because the flow rate of oxidizer across the center is relatively increased, the center of the cell unit is cooled favorably.

[0016] The dimple-like protrusions on the first and second sides of the separator plate and the height variations of the midplane can be formed in a single step to economically produce large electrochemical cells.

[0017] If the separator plate of the 3D region has any ribs and channels, these will inevitably physically separate and thus restrict the flow, meaning that adjusting the height will not be very beneficial. Therefore, the 3D region preferably does not have any elongated rib / channel features on each side of the metal sheet, and as a result, “intermediate planar regions” extending between the protrusions can be fluidly interconnected (e.g., so that dimple-like protrusions do not restrict or block the flow within their respective fluid volumes).

[0018] The electrochemically active cell region may be any type (e.g., solid oxide, polymer electrolyte membrane, etc.) in which a separator plate separates two different fluid flow volumes, such as a fuel volume and an oxidizer volume, and a three-dimensional (3D) region covers at least a portion of the electrochemically active cell region.

[0019] In a preferred embodiment, the 3D region covering the electrochemically active cell region comprises a 3D structure configured not to separate the flow into a separate fluid channel, at least over the upstream half (preferably over the entire) of the electrochemically active cell region. For example, this can be achieved by the 3D structure not including any channels that confine the flow into a separate fluid channel over the upstream half (preferably over the entire) of the electrochemically active cell region.

[0020] Therefore, the dimple-like protrusions (dimples) may have a circular, square, cruciate, pentagonal, or hexagonal cross-section. The cross-section may be elliptical or irregularly polygonal, but ideally, it should have an aspect ratio that does not significantly restrict the flow direction within the fluid volume. The aspect ratio of the dimple-like protrusions may be less than 10, preferably less than 5, and more preferably less than 2. Alternatively or additionally, the length of the dimple-like protrusions may be less than half of the characteristic lateral dimensions (e.g., length, width, or diameter) of the electrochemically active cell region.

[0021] The use of dimple-shaped protrusions reduces the limitations on mixing within the fluid volume compared to conventional channel-shaped separators. It also reduces the contact area of ​​the separator plate with respect to the cell layer. This reduced contact area means that the dimple-shaped protrusions do not obstruct access from the fluid volume to the cell layer as much, thereby improving the power density (in fuel cell operation) or hydrogen production rate (in electrolytic cell operation) of each cell unit.

[0022] The first fluid volume may have a height between 30% and 80% of the height of the second fluid volume, preferably between 40% and 60%. The maximum variation in the height of the first and / or second fluid volume may be between 5% and 50% of the maximum height of the first fluid volume, preferably between 5% and 30%, more preferably between 10% and 20%.

[0023] The cell layer may include one or more electrochemically active cell regions.

[0024] The 3D region may cover all of the electrochemically active cell regions.

[0025] The height of the intermediate planar region may be varied as a discontinuous transition. The height of the intermediate planar region may be varied as a discontinuous (or step-like) transition. In this case, the intermediate planar region includes at least two respective heights for the first and / or second fluid volume with a (discontinuous) step therebetween. Such a stepped transition can be easily formed by pressing, and the influence on the fluid flow rate of each volume can be easily determined. Preferably, there are at least three respective heights for the first and / or second fluid volume, with stepped transitions therebetween.

[0026] Alternatively, the height of the intermediate planar region can be varied as a continuous transition. The height of the intermediate plane may vary continuously in one direction. The continuous variation may be in the form of a linear (flat) inclined surface, or may be a curved profile. The intermediate planar region may be curved in one or two dimensions. In other words, the intermediate planar region includes a curved plane. This provides a fluid volume with a continuously varying height, which controls the flow velocity over the extent of the electrochemically active cell region. The height can be adjusted to control the fluid over the entire extent of the electrochemically active cell region. This can evenly distribute fuel and / or oxidant over the extent of the electrochemically active cell region, and / or can be used to assist cooling of the cell unit by increasing the flow rate of a cooling fluid (e.g., oxidant) in areas of the cell unit that would benefit from additional cooling. The intermediate planar region may include two sub-regions: a first sub-region where the intermediate plane is flat, and a second sub-region where the intermediate plane is curved. The first sub-region may be disposed around the periphery of the separator plate, and the second sub-region may be disposed toward the center thereof. This makes the periphery of the separator plate flat, allowing easy bonding of the separator plate to other plates in the cell unit (e.g., spacer plates and / or cell layers).

[0027] The continuous transition for the height variation of the intermediate plane is further advantageous, as the continuous transition is gradual and thus less likely to disturb the laminar flow in the first and second fluid volumes.

[0028] The electrochemical cell unit may have an inlet to and an outlet from a first fluid volume disposed toward opposite edges of the cell unit, with the electrochemically active cell region disposed therebetween, and at least one direction of the height variation in the intermediate planar region is configured such that the height of the first fluid volume is smaller in the central area of the cell unit than in areas adjacent to the edges of the cell unit.

[0029] The inlet to and outlet from the first fluid volume may be two corresponding fluid ports arranged around the cell unit, thereby collecting and distributing the first fluid internally by a manifold. The inlet to and outlet from the first fluid volume may each comprise one or more inlet ports and one or more outlet ports provided on a separator plate. Typically, the corresponding ports are provided on the cell layer, and these ports are aligned with the ports on the separator plate to form a fluid passage for supplying the first fluid to the first fluid volume of the cell unit and for discharging the first fluid from the first fluid volume. Alternatively, the inlet to and outlet from the first fluid volume may be collected and distributed externally by a manifold using a fluid passage located outside the installation area of ​​the cell unit.

[0030] The central area of ​​the cell unit may have one or both of the length and width equal to the characteristic dimensions (e.g., diameter or width) of the inlet to the first fluid volume and the outlet therefrom. In some cases, the central area may have a width equal to the characteristic dimensions of the inlet to the first fluid volume and the outlet therefrom, and a length less than or equal to the distance between the inlet to the first fluid volume and the outlet therefrom (e.g., 50-70% of the distance).

[0031] The lower the height of the first fluid volume in the central area of ​​the cell unit, the more restricted the fluid flow rate in that portion of the fluid volume; conversely, the higher the height to the edges of the cell unit, the less restricted the flow rate. These edges may include all edges, including those where the inlet to and outlet from the first fluid volume are located, or they may include only the edges other than those where the inlet to and outlet from the first fluid volume are located. The flow rate of the first fluid in areas with higher heights increases compared to the flow rate when the height of the midplane is constant. As a result, the change in the height of the midplane allows the first fluid to be distributed more uniformly over the electrochemically active cell region (typically located between the inlet to and outlet from the first fluid volume). Since the heights of the first and second fluid volumes are interrelated, the lower the height of the first fluid volume, the greater the height of the second fluid volume, and correspondingly the greater the second fluid flow rate. A larger second fluid flow rate may be beneficial, for example, for evenly distributing heat across the entire area of ​​the cell unit.

[0032] At least one direction of height change in the intermediate plane region may be approximately perpendicular to the straight line between the inlet to the first fluid volume and the outlet from the first fluid volume, and the height of the first fluid volume may be smaller along the straight line than on at least one side of the straight line.

[0033] In other words, the height of the first fluid volume may be small along a straight line between the inlet to the first fluid volume and the outlet from the first fluid volume, and the height of the first fluid volume may be large in the area on at least one side of the straight line. It will be understood that the straight line may feature a sub-region (e.g., along its center) having a width greater than or equal to the width (or diameter) of the inlet and outlet. Preferably, the change in height is symmetrical with respect to the straight line, in which case greater heights are provided on both sides of the straight line. The inlet to the first fluid volume and the outlet therefrom may each comprise one or more inlet ports and one or more outlet ports provided on a separator plate. Typically, the corresponding ports are provided on the cell layer, and these ports are aligned with the ports on the separator plate to form a fluid passage for supplying the first fluid to the first fluid volume of the cell unit and for discharging the first fluid from the first fluid volume.

[0034] The lower the height of the first fluid volume along a straight line, the more it restricts the fluid flow rate along that line; conversely, the higher the height on the side of the line, the less restrictive it becomes. The flow rate of the first fluid in areas with higher heights increases compared to the flow rate when the height of the midplane is constant. As a result, the change in the height of the midplane allows the first fluid to be distributed more uniformly over the electrochemically active cell region (typically located between the inlet and outlet of the first fluid volume). Since the heights of the first and second fluid volumes are interrelated, the lower the height of the first fluid volume, the greater the height of the second fluid volume, and correspondingly the greater the flow rate of the second fluid. A larger flow rate of the second fluid can be beneficial, for example, for evenly distributing heat across the entire area of ​​the cell unit.

[0035] In other words, at least one direction across the active cell region is perpendicular to the direction of fluid flow within the first fluid volume.

[0036] In some cases, at least one direction of height change in the intermediate plane region does not have a component that is substantially parallel to the straight line between the inlet to the first fluid volume and the outlet from the first fluid volume. However, in some cases, at least one direction of height change in the intermediate plane region has two directions in which the height changes (i.e., a component parallel to the straight line between the inlet to the first fluid volume and the outlet from the first fluid volume, and a component perpendicular to it).

[0037] In an alternative example, the electrochemical cell unit has an inlet and outlet to a first fluid volume positioned toward opposing edges of the cell unit, with electrochemically active cell regions located between them, such that at least one direction of height change in the midplanar region causes the height of the first fluid volume to decrease from the inlet to the outlet. This may improve the utilization rate of the first fluid in the electrochemical cell unit.

[0038] In this example, the electrochemical cell unit may include an inlet and outlet to a second fluid volume located toward or outward from the opposing edges of the cell unit, between which the electrochemically active cell regions are positioned, with the inlet and outlet of the second fluid volume arranged such that the height of the second fluid volume increases from the inlet to the outlet. When operating as a fuel cell with the first fluid volume for fuel and the second fluid volume for oxidizer, increasing the height of the second fluid volume along the flow path of the second fluid volume increases the flow rate of the second fluid in the relatively hot areas of the stack (due to the co-flow configuration of fuel and oxidizer, the downstream area of ​​the first fluid volume is generally hotter than the upstream area during fuel cell operation), thereby improving cooling and enhancing fuel cell performance.

[0039] If the inlet and outlet to the second fluid volume are located toward opposing edges of the cell unit, the second fluid volume is collected and distributed internally by a manifold. If the inlet and outlet to the second fluid volume are located outside the opposing edges of the cell unit, the second fluid volume is collected and distributed externally by a manifold, thereby increasing the surface area of ​​the electrochemically active cell region.

[0040] In this example, the electrochemical cell unit may include a bypass for the second fluid around a portion of the 3D region adjacent to the inlet to the second fluid volume. This further increases the flow rate of the second fluid in the relatively hot areas of the stack (due to the co-flow of fuel and oxidizer), thereby improving cooling and enhancing the performance of the fuel cell.

[0041] Preferably, the three-dimensional (3D) region covers the entire electrochemically active cell region. Preferably, when the 3D region completely covers the electrochemically active cell region, the changes in the intermediate planar region can be used to guide (i.e., evenly distribute) the fluid across the range of the electrochemically active cell region, thereby improving the performance of the cell unit. Preferably, the design of the 3D region and dimple-like protrusions allows mixing within the entire range of the first fluid volume and the entire range of the second fluid volume.

[0042] Preferably, however, if, for example, the height of the adjusted midplane is not required at the downstream end portion of the electrochemically active area, the 3D region of the separator plate does not need to completely cover the electrochemically active area.

[0043] Furthermore, if, for example, height adjustment is desired in a portion of the separator plate immediately upstream of the active cell region, the 3D region of the separator plate having the height of the adjusted midplane may extend beyond the electrochemically active cell region it faces.

[0044] Preferably, the dimple-like protrusions of the first and second plurality of dimple-like protrusions are shaped such that their outermost portions do not include any lateral contact portions that extend in the height direction, so as to form channels within the fluid volume in which the fluid is constrained.

[0045] As a result, fluid passages within the fluid volume may intersect with each other at multiple points, and the fluids may mix within the fluid volume.

[0046] Preferably, the first side of the separator plate faces the cell layer, and each contact portion of the first plurality of dimple-like protrusions contacts the cell layer.

[0047] The first set of dimple-like protrusions contacts the cell layer, thereby providing electrical contact between the separator plate and the cell layer (in which the separator plate is located). The contact also mechanically supports each plate and transmits compressive force through the stack of cell units. This compressive force then results in good electrical contact between the dimple-like protrusions and the cell layer. The contact portions of the second set of dimple-like protrusions are configured to contact the cell layer of adjacent cell units in the stack of cell units in order to provide electrical and mechanical contact.

[0048] The outermost point of the dimple-shaped projection may have a flat top to form a contact area.

[0049] In one example, each contact point of the first set of dimples and each contact point of the second set of dimples form a first and second plane, respectively, and the first and second planes are both planes and parallel to each other.

[0050] This allows multiple electrochemical cell units to be stacked on top of each other to form a stack of cell units.

[0051] The present invention is applicable to any type of electrochemical cell in which a metal separator sheet is superimposed on the cell layer of each cell unit, and the cells (e.g., planar) are stacked on top of each other during use. Examples of cell types include PEM cells, solid oxide cells, and proton-conducting cells. The cell architecture may be such that the cell chemical layers are structurally supported by metal substrates or ceramics, such as anode layers, electrolyte layers, and cathode layers.

[0052] The cell unit architecture can be selected from one of the following: metal-supported, anode-supported, electrolyte-supported, or cathode-supported architectures.

[0053] Preferably, the cell unit is a metal-supported cell unit in which the cell layer comprises a metal support plate on its first side that supports an electrochemically active cell region provided on a porous region.

[0054] In some cases, the porous region is formed by holes drilled in a metal support plate, usually with a laser.

[0055] In some examples, the (active) fuel cell chemical layer takes the form of an electrochemically active layer comprising an anode, electrolyte, and cathode (e.g., coated or deposited) formed on the metal support plate on a porous region provided within the metal support plate in such embodiments. In this configuration, where the (non-self-supporting, thin) electrochemically active cell region is directly provided on the metal support plate, the number of required parts is minimized. Thus, the metal support plate performs a dual function: supporting the electrochemically active cell region and (together with the separator plate) defining the fluid volume. Furthermore, it will be understood that both the metal support plate and the separator plate have a side exposed to the oxidizer and a side exposed to the fuel, and are therefore components exposed to a harsh dual atmospheric environment.

[0056] In an alternative framed embodiment, the porous regions are provided on each plate (e.g., metal foil) on which the electrochemically active cell regions are formed (e.g., coated or deposited), and each separate plate (carrying the electrochemically active cell regions) is provided on a window (e.g., frame) on a metal support plate.

[0057] Multiple areas of electrochemically active cell regions may exist. For example, a metal support plate covered by separate electrochemically active cell regions may have multiple areas of small holes. Alternatively, there may be multiple windows in the metal support plate, and multiple separate plates on which electrochemically active cell regions are formed. These plates, or each separate plate, may be welded to the metal support plate on the windows of the metal support plate.

[0058] In one example, at least one of the separator plate and the metal support plate has a flanged peripheral feature formed by pressing the plate into a concave configuration, and the separator plate and the metal support plate are directly joined at the flanged peripheral feature and optionally welded to form a first fluid volume between them.

[0059] The cell unit can be sealed around a flanged peripheral feature to form a first fluid volume. Sealing can be performed by welding around the flanged peripheral feature. Welding can also be used around ports formed in the separator plate and cell layer to seal the first fluid volume from the second fluid volume. The cell may comprise a metal substrate and a separator plate, at least one of which has a flanged peripheral feature. This eliminates the need for spacers, thus reducing the number of parts and material waste. Furthermore, the two metal plates can also be electrically connected, which is advantageous.

[0060] The first side of the separator plate may face the second side of the metal support plate (of the cell unit in which the separator plate is placed), and an electrochemically active cell region is supported on the second side of the metal support plate opposite to the first side. In this case, the height of the first plurality of dimple-like protrusions may be equal to the height of the flanged peripheral feature, so that both the first plurality of dimple-like protrusions and the flanged peripheral feature contact the second side of the metal support plate. In other words, the plane formed by the peaks of the dimple-like protrusions coincides with the contact area of ​​the flanged peripheral feature. Preferably, the flanged peripheral feature is formed on the separator plate (i.e., not on the metal support plate) in the same step as forming the 3D region therein. This may eliminate the need to form the metal support plate.

[0061] Preferably, at least one of the separator plate and the metal support plate is provided with a molded port feature formed by press working around at least one fluid port, the molded port feature extending toward the other plate, and the elements of the molded port feature are spaced apart from each other to define a fluid passage from the port to the elements, allowing fluid to pass from at least one first fluid port to a first fluid volume. If the molded port features are formed on the separator plate, they may be formed in the same steps as forming the 3D regions.

[0062] As an alternative to flanged peripheral features, the electrochemical cell unit comprises a spacer plate positioned between a metal support plate and a separator plate, the spacer plate having an opening therein that defines a first fluid volume, and the metal support plate, spacer plate, and separator plate are joined around its periphery.

[0063] In this case, the cell layer (its metal support plate) and the separator plate are indirectly connected to form a stacked arrangement, with a (flat) metal spacer plate positioned between them. The first side of the separator plate may face the spacer plate, and the first plurality of dimple-like protrusions extend through the opening in the spacer plate toward the cell layer. The cell layer (its metal support plate), the separator plate, and the intermediate metal spacer plate can be sealed together, for example, by welding through all three components, at least around them. When spacers are used, the fluid is typically ejected from the narrow passages within the spacers in only a limited number of directions. Thus, the present invention is particularly applicable in that it promotes uniform distribution of the fluid into the active cell region despite restricted intrusion.

[0064] When the spacer is positioned between two separate metal plates, this has the disadvantage of requiring extra components in the stack, but it has the advantage that planar metal plates can be used and the electrochemically active cell region can be easily placed directly on them by conventional coating or spray deposition techniques. The spacer may be sandwiched between flat metal substrates, forming a volume for the first fluid volume, and may comprise a frame or flat peripheral component (positioned beyond the electrochemically active cell region) that seals and surrounds the first fluid volume.

[0065] The first side of the separator plate may face the second side of the metal support plate (of the cell unit in which the separator plate is placed), and an electrochemically active cell region is supported on the second side of the metal support plate opposite to the first side. In this case, the height of the first plurality of dimple-like protrusions may be equal to the thickness of the spacer plate, and both the first plurality of dimple-like protrusions and the side of the spacer plate opposite to the separator plate are in contact with the second side of the metal support plate. In other words, the plane formed by the peaks of the dimple-like protrusions coincides with the contact area of ​​the spacer plate.

[0066] Preferably, the first fluid volume is for fuel and the second fluid volume is for oxidizing agent.

[0067] Preferably, the height of the first fluid volume is lower than the height of the second fluid volume.

[0068] Preferably, the height of the first fluid volume is lower than the height of the second fluid volume throughout the entire intermediate plane region. Alternatively, the change in height of the intermediate plane region is such that in some parts of the cell unit the height of the first fluid volume is lower than the height of the second fluid volume, and in other parts the height of the first fluid volume is higher than the height of the second fluid volume.

[0069] For example, the first fluid volume may be for fuel and the second fluid volume for oxidizer. In such a case, to operate the electrochemical cell unit as a fuel cell, the height of the first fluid volume can be lower than the height of the second fluid volume. In contrast, to operate the electrochemical cell unit as an electrolytic cell, the height of the first fluid volume can be higher than the height of the second fluid volume.

[0070] Preferably, at least one fluid port is provided in each of the separator plate and the cell layer, which are aligned to form a first fluid passage within the periphery of the separator plate and the cell layer, and each port is in fluid communication with the first fluid volume.

[0071] Preferably, there are at least first and second fluid ports, which are aligned to form first and second fluid passages, respectively, around the separator plate and cell layer, and are in fluid communication with a first fluid volume, the first fluid passage being configured to supply a first fluid to the first fluid volume, and the second fluid passage being configured to discharge the first fluid from the first fluid volume. In this case, the first and second fluid passages are located at or near opposing cell ends, and the electrochemically active cell region is located between the first and second fluid passages. Opposing cell ends may be opposing sides of a square or rectangular cell, or opposing ends of a diameter across a circular cell.

[0072] According to an alternative embodiment, an electrochemical cell unit is provided, A cell layer containing an electrochemically active cell region (the cell layer may be a metal support plate that supports the electrochemically active cell region provided on a porous region), A separator plate having a plurality of first dimple-shaped protrusions that extend outward from the intermediate plane of the separator plate and form protrusions on the first side of the separator plate, The interconnecting plates and metal support plates overlap each other to form repeating units. The first set of dimple-like protrusions are distributed over a separator plate that covers at least a portion (preferably the entirety) of the electrochemically active cell region, and the dimple-like protrusions on the first side of the separator plate contact the cell layer (metal support plate or its electrochemically active area), thereby separating the separator plate from the cell layer (metal support plate or electrochemically active area) and defining a first fluid volume between them. The separator plate has at least a first sub-region and a second sub-region, and the first plurality of dimple-like protrusions include at least a first subset of dimple-like protrusions in the first sub-region and a second subset of dimple-like protrusions in the second sub-region, the first subset of dimple-like protrusions having a first height and the second subset of dimple-like protrusions having a second height, thereby forming corresponding first and second separation sub-regions between the intermediate plane of the separator plate and the cell layer (metal support plate or its electrochemically active area).

[0073] The intermediate plane of the separator plate (and the heights of the first and second subsets of dimple-like protrusions) can be modified, for example, to guide a first fluid into a first fluid volume in order to promote a uniform distribution of fuel or oxidizer across the electrochemically active cell region and / or to improve the heat distribution across the electrochemically active cell region.

[0074] The separator plate may include a second plurality of dimple-like projections extending outward from the midplane of the separator plate and forming projections on the second side of the separator plate. The second plurality of dimple-like projections, like the first plurality of dimple-like projections, may have at least first and second subsets of different heights that project from the changing midplane of the separator plate.

[0075] In a further alternative embodiment, an electrochemical cell unit is provided, A separator plate having a first surface and a second surface, It includes a cell layer containing an electrochemically active cell region (the cell layer may be a metal support plate that supports the electrochemically active cell region provided on a porous region), The separator plate and cell layer overlap each other to form repeating units, defining the first fluid volume between them. The separator plate has a first plurality of dimple-like protrusions on a first side, and the first plurality of dimple-like protrusions are distributed over a range of the separator plate corresponding to a range of electrochemically active areas, thereby defining fluid passages within a first fluid volume that meander and / or intersect each other at multiple positions. The first fluid volume between the opposing ends of the cell unit contains at least two flow paths, each flow path experiencing a different volume depth of the first fluid volume.

[0076] The difference in volume depth may be due to different midplanes of the separator plate, which are the planes from which the dimple-like protrusions extend. The height of the dimple-like protrusions changes in accordance with the changing midplane. Of the at least two channels, the first channel (i.e., streamline) can take the shortest possible distance between its inlet to the first fluid volume and its outlet, and the second channel of the at least two can take a longer distance between its inlet to the first fluid volume and its outlet. The second channel does not intersect the first channel. In this case, the volume depth of the first channel is less than that of the second channel. This has the effect of increasing the flow rate of the first fluid along the second channel (compared to the flow rate that would exist if the volume depths of the first and second channels were equal), and thus more evenly distributing the fluid within the first fluid volume.

[0077] The separator plate may have a second plurality of dimple-like projections extending outward from the separator plate and forming projections on the second side of the separator plate. The second plurality of dimple-like projections may vary in height, similar to the first plurality of dimple-like projections. The separator plate may also be a pressed sheet, in which case the volume depth of the second fluid volume on the second side of the separator plate varies in correspondence with the volume depth of the first fluid volume.

[0078] In a further alternative embodiment, an electrochemical cell unit is provided, A cell layer containing an electrochemically active cell region, It includes a separator plate containing a metal sheet covering the cell layer, The separator plate has selectively molded three-dimensional (3D) regions that at least partially or completely cover the electrochemically active cell regions. In that three-dimensional (3D) domain, The metal sheet has a first plurality of outwardly extending dimple-like protrusions that define the height of the first fluid volume on the first side of the separator plate, In addition, the metal sheet has a second plurality of outwardly extending dimple-like protrusions that define the height of the second fluid volume on the second side of the separator plate. As a result, the intermediate planar region is positioned between the protrusions. The intermediate planar region is formed such that its height is selectively varied in at least one direction across the active cell region such that the height of one or both of the first and second fluid volumes increases and / or decreases accordingly.

[0079] An electrochemical cell stack comprising multiple of the above electrochemical cell units is further provided. The first side of the separator plate of the first electrochemical cell unit faces the cell layer of the first electrochemical cell unit, and a first fluid volume is enclosed (or defined) between them. The second side of the separator plate of the first electrochemical cell unit faces the cell layer of an adjacent second electrochemical cell unit in the stack of cell units, enclosing (or defining) the second fluid volume between them.

[0080] In this case, the first set of dimple-like protrusions on the separator plate of the first electrochemical cell unit may contact the cell layer of the first electrochemical cell unit, and in this case, the second set of dimple-like protrusions on the separator plate of the first electrochemical cell unit may contact the cell layer of an adjacent second electrochemical cell unit. Typically, the electrochemically active cell region is located on the first side of the cell layer (e.g., the first side of the metal support plate, or supported by the metal support plate), so the second set of dimple-like protrusions contact the electrochemically active cell region (outermost layer) of the second adjacent electrochemical cell unit. Thus, the first set of dimple-like protrusions typically contact another location on the cell layer of the first electrochemical cell unit (e.g., contact the second side of the metal support plate).

[0081] The electrochemical cell stack may further include means for supplying and discharging a first fluid from a first fluid volume positioned toward opposing edges of a cell unit, between which electrochemically active cell regions are located, such that at least one direction of height variation in the intermediate planar region is such that the height of the first fluid volume is smaller in the central area of ​​the cell unit than in the area adjacent to the edges of the cell unit.

[0082] The electrochemical cell stack may further include means for supplying and discharging a first fluid from a first fluid volume, the electrochemically active cell region being positioned between the supply and discharge means, at least one direction of height variation of the midplane being perpendicular to a straight line between the supply and discharge means of the first fluid, and the height of the first fluid volume being smaller along the straight line than on at least one side of the straight line.

[0083] Preferably, the change in height is symmetrical with respect to the line, in which case greater heights are provided on both sides of the line.

[0084] In some examples, the electrochemical cell stack further comprises means for supplying and discharging a first fluid from a first fluid volume, with an electrochemically active cell region positioned between the supply and discharge means, and at least one direction of height change in the intermediate planar region such that the height of the first fluid volume decreases from the supply means to the discharge means of the first fluid volume.

[0085] In such an example, the electrochemical cell stack may include means for supplying and discharging a second fluid from a second fluid volume, and the electrochemically active cell region is located between the means for supplying and discharging the second fluid from the second fluid volume, and at least one direction of height change in the intermediate plane region is such that the height of the second fluid volume increases from the means for supplying the second fluid volume to the means for discharging it. Preferably, the electrochemically active cell region and the means for supplying and discharging a first fluid from a first fluid volume are located between the means for supplying and discharging the second fluid from the second fluid volume.

[0086] In such an example, the electrochemical cell stack may be located within a housing and may be provided with baffles configured to provide a bypass for the second fluid around a portion of the 3D region adjacent to the means for supplying the second fluid to the second fluid volume.

[0087] Means for supplying and discharging the first fluid from the first fluid volume may comprise at least one fluid port provided through a separator plate and a cell layer in fluid communication with the first fluid volume, wherein at least one fluid port of each cell unit is aligned to form at least one passage extending in the stack direction, which is a passage collected and distributed internally by a manifold. The passage collected and distributed internally by the manifold is defined by at least one aligned fluid port located around each cell unit.

[0088] In such stacks, which have internal passages for collection and distribution via manifolds, typically, Each electrochemical cell unit comprises two first fluid ports in which an electrochemically active cell region is in fluid communication with a first fluid volume located between them. The first fluid port is for supplying the first fluid to a first volume, and the second fluid port is for discharging the first fluid from the first fluid volume. At least one direction of height change in the intermediate plane region is approximately perpendicular to the straight line between the first fluid port and the second fluid port, and the height of the first fluid volume is smaller along the straight line than on at least one side of the straight line.

[0089] In this case, the first and second ports are aligned to define the first and second first fluid passages, respectively, that extend in the stack direction, forming an inlet passage and an outlet passage, respectively.

[0090] In stacks where distribution is further handled by a manifold, generally, Each electrochemical cell unit comprises four first fluid ports that fluidly communicate with a first fluid volume arranged in a cross shape, with the electrochemically active cell region positioned between them. Two adjacent fluid ports are for supplying the first fluid to the first fluid volume, and the remaining two fluid ports are for discharging the first fluid from the first fluid volume.

[0091] Each of the four ports is aligned to define four separate first fluid passages extending in the stacking direction, each forming two inlet passages and two outlet passages. In this case, the cell unit may have a rectangular shape, and the four ports may each be positioned toward a different corner of the cell unit. This configuration of the first fluid ports can also be used with other cell shapes, such as a hexagon, where, for example, two adjacent ports for the inlet of the first fluid are positioned toward opposing ends of the first side, and two adjacent ports for the discharge of the first fluid are positioned toward opposing ends of the second side, with the second side facing the first side.

[0092] In stacks where distribution is further handled by a manifold, generally, Each electrochemical cell unit comprises four first fluid ports that fluidly communicate with a first fluid volume arranged in a cross shape, with the electrochemically active cell region positioned between them. Two opposing fluid ports are for supplying the first fluid to the first fluid volume, and the remaining two opposing fluid ports are for discharging the first fluid from the first fluid volume.

[0093] Each of the four ports is aligned to define four separate first fluid passages extending in the stacking direction, each forming two inlet passages and two outlet passages. In this case, the cell unit has a rectangular shape, and the four ports may be positioned midway along the length of the cell unit, each toward a different edge of the cell unit. In the case of a rectangular cell, the inlet port is at the center of the short side and the outlet is at the center of the long side (or vice versa). Opposite ports are ports located on the opposite side of the electrochemically active cell region.

[0094] In a stack further inside, where fluids are collected and distributed by a manifold, each electrochemical cell unit typically has three first fluid ports that communicate with a first fluid volume arranged in a V-shape. a) The first port is for supplying the first fluid to a first fluid volume, the second and third ports are for discharging the first fluid from the first fluid volume, the first port is opposite the second and third fluid ports, and the electrochemically active cell region is positioned between them, or b) The first port is for discharging the first fluid from the first fluid volume, and the second and third ports are for supplying the first fluid to the first fluid volume, with the first port facing the second and third fluid ports, and the electrochemically active cell region positioned between them.

[0095] In other words, the three first fluid ports communicating with the first fluid volume are located at the corners of a V-shape, with the electrochemically active cell region positioned between them. The port at one point of the V-shape is either an inlet or an outlet, while the other two ports are the inlet and outlet. In this case, the cell unit may have a rectangular shape, in which case the ports are usually positioned toward the opposing short sides. This configuration may also be suitable for a triangular cell unit, with one port positioned toward each corner.

[0096] Each electrochemical cell unit in the stack may further include a second fluid intermediate port located midway along the length and width of each cell unit, the second fluid intermediate port being in fluid communication with a second fluid volume, and the second fluid intermediate ports of each cell unit being aligned to form at least one intermediate passage extending in the direction of the stack.

[0097] At least one second fluid end passage, which is in fluid communication with the second fluid volume, may be provided so as to extend in the stack direction at or near the cell end, and at least one second fluid end passage is a passage that is collected and distributed externally by a manifold beyond each cell unit.

[0098] Typically, the first fluid volume is the fuel volume, and the second fluid volume is the oxidizer volume. The pressure drop over the length of the active cell chemistry is usually more pronounced for the oxidizer, and therefore, the gap between adjacent cell units is generally larger than the gap between the metal substrate and the separator plate within the cell unit that defines the second fluid volume; therefore, it is preferable that the second fluid, collected externally by a manifold, be the oxidizer. This means that the first fluid volume, in this case the fuel, is contained or sealed within the cell unit and in fluid communication with the first fluid passage. Furthermore, if the first fluid volume (enclosed by the cell unit) is adapted to air, the gap between the metal substrate and the separator plate needs to be larger, which requires more material to form a larger gap and therefore increases the stacking cost.

[0099] In a stack further inside which fluids are collected and distributed by a manifold, typically a second fluid intermediate port is an inlet port for supplying the second fluid to a second fluid volume, and each of at least one second fluid end passage is for discharging the second fluid from the second fluid volume.

[0100] For cell units with three or more sides, there may be one second fluid end passage on the outside of each side of the cell unit (i.e., the number of second fluid end passages is equal to the number of sides of the cell unit). Alternatively, two second fluid end passages may be provided at opposing cell ends (e.g., opposing short or long edges of a rectangular cell unit, or opposing edges of a hexagonal cell unit), or two pairs of second fluid end passages may be spaced apart around the cell unit (e.g., outside each edge of a rectangular cell unit).

[0101] Instead of providing a second fluid intermediate port, the second fluid may be collected entirely externally by a manifold. This maximizes the proportion of the layer covered by the electrochemically active cell region, thereby improving power density.

[0102] In stacks where fluid is collected and distributed externally by a manifold, typically, two second fluid end passages are provided that are in fluid communication with a second fluid volume, extending in the direction of the stack at or near opposing cell ends, the second fluid end passages being passages that are collected and distributed externally by a manifold beyond each cell unit, one of the second fluid end passages being for supplying the second fluid to the second fluid volume, and the other of the second fluid end passage being for discharging the second fluid from the second fluid volume.

[0103] Alternatively, in a stack collected and distributed externally by a manifold, four second fluid end passages, which are in fluid communication with a second fluid volume, are provided extending in the direction of the stack and arranged in two pairs, with each pair of passages facing each other with an electrochemically active cell region positioned between them, and these are passages collected and distributed externally by a manifold beyond each cell unit, the first pair being for supplying the second fluid to the second fluid volume, and the second pair being for discharging the second fluid from the second fluid volume, with the outlet passages and inlet passages arranged alternately around the cell unit.

[0104] In a preferred example, each electrochemical cell unit comprises first and second fluid ports provided through a separator plate and a cell layer that is in fluid communication with a first fluid volume, wherein each fluid port in each cell unit is aligned to form respective first and second passages extending in the stack direction, which are passages collected and distributed internally by a manifold. In this case, the first fluid port is for supplying the first fluid to the first volume, and the second fluid port is for discharging the first fluid from the first fluid volume, and at least one direction of height change in the intermediate planar region is approximately perpendicular to the line between the first and second fluid ports, and the height of the first fluid volume is smaller along the line than on at least one side of the line. As a result, the height of the first fluid volume is usually lower toward the center of the cell unit. In this case, the cell unit has a rectangular shape, and the first fluid ports are positioned toward the opposing short ends of the cell unit. Preferably, this first fluid volume is for fuel. Since the height of the second fluid volume changes in accordance with the height of the first fluid volume (for example, because the separator plate deforms to form a 3D region), the second fluid (oxidizer) can be collected externally by a manifold so that it flows in the same direction as the flow direction of the first fluid, or in the opposite direction to the flow direction of the first fluid (i.e., 180 degrees). This is advantageous because it increases the flow rate of the oxidizer to the center of the cell unit, thereby enhancing the cooling of the center of the cell unit when it is operating as an SOFC.

[0105] In the above, the first fluid channel in the first fluid volume is formed between an inlet to the first fluid volume and an outlet therefrom, and the second fluid channel is formed between an inlet to the second fluid volume and an outlet therefrom.

[0106] In a preferred example, the first and second fluid channels are configured to flow together across the electrochemically active cell region. The fluid may flow in a co-flow configuration where both the first and second fluid channels flow from one end of the cell unit to the opposite end of the cell unit.

[0107] Alternatively, the fluid may be configured in reverse flow, in which case the first fluid passage is from the first end of the cell unit to the opposing second end of the cell unit, and the second fluid passage is from the second end of the cell unit to the opposing first end of the cell unit, or vice versa.

[0108] Alternatively, the fluid may be configured to flow in both directions, in which case the first fluid passage extends from the first end of the cell unit to the opposing second end of the cell unit, and the second fluid passage extends from each end of the cell unit to the center of the cell unit (or vice versa). That is, the second fluid passage extends from the intermediate passage to the end passage (or vice versa), and the first fluid passage extends from the end fluid passage at one end of the cell to the end passage at the opposite end of the cell.

[0109] Alternatively, the fluid may be in a cross-flow configuration, in which the first fluid passage is from a first end of the cell unit to the opposing second end of the cell unit (or vice versa), the second fluid passage is substantially perpendicular to the first fluid passage, and the second fluid passage is from a third side of the cell unit to a fourth side of the cell unit. The third and fourth sides are different from the opposing first and second sides.

[0110] Co-flow configurations can be preferable because, in contrast to reverse flow, the hottest part of the cell unit is directed toward the edges of the cell unit, as opposed to reverse flow where the hottest part of the cell unit is directed toward the center of the active cell chemical region. Therefore, in the case of reverse flow, the measured temperature of the discharged fluid better reflects the highest temperature of the stack, which is an important parameter because excess heat can lead to cell unit failure. Furthermore, in reverse flow, the highest temperature is usually higher than in the case of co-flow (all other parameters are equal), so a larger fluid flow rate (usually using an oxidizer flow) is required for cooling in a reverse flow configuration, resulting in increased parasitic losses from the blower or pump compared to a co-flow configuration.

[0111] In a second embodiment, a method for manufacturing a separator plate is provided. To provide a flat metal sheet, This includes deforming a metal sheet to provide a three-dimensional (3D) region, where the three-dimensional (3D) region is A first plurality of outwardly extending dimple-like protrusions define the height of the first fluid volume on the first side of the separator plate, It includes a second plurality of outwardly extending dimple-like protrusions that define the height of the second fluid volume on the second side of the separator plate, As a result, the intermediate planar region is positioned between the protrusions. The intermediate planar region is shaped to selectively change its height in at least one direction across the active cell region such that the corresponding heights of the first and second fluid volumes increase and decrease accordingly.

[0112] Since the separator plate is formed by deforming (pressing) a metal plate, the dimple-like protrusions on the first side of the separator plate appear as dimple cavities on the second side of the separator plate, and so do other features formed therein. This link may be perceived as a disadvantage from a design standpoint in that it results in a loss of degrees of freedom. However, the deformation process for forming the metal sheet can be used economically to produce electrochemical cells on a large scale, and at the same time, the link can also be used to adjust the balance between the first and second fluid volumes, respectively, to achieve improved technical performance, taking into account the port configuration, flow paths, and thermal profile in the cell in question. For example, in an SOFC, if the height of the midplane is such that the height of the fuel volume decreases toward the center of the cell unit, then the oxidizer volume increases accordingly toward the center of the cell unit, thereby increasing the flow rate of oxidizer across the center of the cell unit. The oxidizer may be used to cool the cell unit, and the center of the cell unit is usually the hottest part of the cell unit. Because the flow rate of oxidizer across the center is relatively increased, the center of the cell unit is cooled favorably.

[0113] This method may further include forming at least an inlet to a first fluid volume and an outlet from the first fluid volume. These may be formed in the step of deforming a metal sheet to provide a three-dimensional (3D) region by forming respective ports that penetrate the metal sheet.

[0114] Preferably, in the same step in which the intermediate planar region and protrusions are formed, any one or more of the 3D features of the molded port features, flanged peripheral features, and other molded flow control features are also formed on the separator plate.

[0115] The method may include providing a cell layer on its first surface, which includes a metal support plate supporting an electrochemically active cell region; providing the separator plate; and joining the metal support plate and the separator plate such that a three-dimensional (3D) region of the separator plate covers the cell layer (i.e., the 3D region covers at least a portion, preferably all, of the electrochemically active cell region), optionally including welding the metal support plate and the separator plate together around their periphery. The metal support plate may be provided with fluid ports corresponding to fluid ports formed in a metal sheet (e.g., by pressing).

[0116] The method may further include stacking a plurality of electrochemical cell units, each formed such that a first side of the separator plate of a first electrochemical cell unit faces the cell layer of the first electrochemical cell unit, with a first fluid volume sealed between them, and a second side of the separator plate of a first electrochemical cell unit faces the cell layer of an adjacent second electrochemical cell unit in a stack of cell units, with a second fluid volume sealed between them.

[0117] The first fluid volume and the second fluid volume may be configured to flow together (i.e., the volumes may be configured such that the first and second fluids flow substantially in the same direction). The first and second fluids may flow together on two opposing surfaces of the separator plate. The stack (and / or cell units within it) may be provided with at least an inlet to the first fluid volume and an outlet therefrom. Similarly, it may be provided with at least an inlet to the second fluid volume and an outlet therefrom. A separator plate formed by the above method is further provided.

[0118] The use of the electrochemical cell unit described above is further provided, and the shape of the intermediate planar region is selectively adjusted to optimize the distribution of the first fluid in the first fluid volume, taking into account the number and location of each inlet and outlet through which the first fluid enters and exits the cell unit during operation. Alternatively, or additionally, the shape of the intermediate planar region is selectively adjusted to optimize the distribution of the second fluid in the second fluid volume, taking into account the number and location of each inlet and outlet through which the second fluid enters and exits the cell unit during operation.

[0119] As shown above, the terms "cell unit" or "cell stack" are used to refer to an "electrochemical cell unit" or "electrochemical cell stack."

[0120] Specific preferred embodiments of the present invention are described in the appended independent claims. Combinations of features from the dependent claims may be combined with features of the independent claims, not merely as explicitly described in the claims, but as desired and appropriate. The term “comprising” as used herein to define the inclusion of components also includes embodiments in which no further components exist.

[0121] This specification contains disclosures of the present invention that would be useful to those skilled in the art. One or more examples of embodiments of the present invention are described below with reference to details. Each example is provided for illustrative purposes only and is not intended to limit the present invention. [Brief explanation of the drawing]

[0122] Next, the features of the present invention will be described in more detail by various embodiments and, merely as examples, with reference to the accompanying drawings (the drawings are not to scale, and height dimensions are generally exaggerated for clarity).

[0123] [Figure 1] This is an exploded perspective view of a conventional cell unit. [Figure 2] This is a schematic plan view showing a portion of a conventional separator plate. [Figure 3A] This is an exploded perspective view of two cell units according to the present invention. [Figure 3B] Figure 3A shows a perspective view and a plan view including the relevant cross-section of the separator plate. [Figure 3C] Figure 3A shows a perspective view and a plan view including the relevant cross-section of the separator plate. [Figure 4A] This is an exploded perspective view of two cell units according to the present invention. [Figure 4B] Figure 4A shows a plan view of the separator plate and related cross-sections. [Figure 4C] Figure 4A shows a plan view of the separator plate and related cross-sections. [Figure 5] This is a plan view and a related cross-sectional view of a further separator plate according to the present invention. [Figure 6] This is a plan view and a related cross-sectional view of a further separator plate according to the present invention. [Figure 7] This is a perspective view of a further separator plate according to the present invention. [Figure 8] This is a perspective view of a further separator plate according to the present invention. [Figure 9] This is a schematic plan view of a further separator plate according to the present invention. [Figure 10] This is a schematic plan view of the port and manifold configuration for the first and second fluids according to the present invention. [Figure 11] This is a plan view and a related cross-sectional view of a further separator plate according to the present invention. [Figure 12] Figure 11 is a cross-sectional plan view of the stack. [Figure 13] This is a cross-sectional plan view of a modified example of the stack shown in Figure 12.

[0124] In the following diagrams and descriptions, similar elements in different diagrams will use the same reference numbers. [Modes for carrying out the invention]

[0125] Referring to Figure 3A, an exploded view of two cell units 301a and 301b of an electrochemical cell stack configuration 300 is shown. The number of cell units has been reduced for illustrative purposes and is usually much larger (e.g., 300). Each cell unit comprises a cell layer 305 (including a metal support plate or substrate) and a separator (or interconnect) plate 315, which may be similar to those described in the applicant's previous patent application WO 2020 / 126486 A1. The cell layer 305 and the separator plate 315 are each freestanding plates. A spacer 310 is provided to separate the separator plate 315 from the substrate 305. Each cell layer 305 is deposited (e.g., as a thin coating / film) on a metal support plate (e.g., a self-supporting metal / steel plate or foil) and includes an electrochemically active cell region 307 comprising an anode layer, an electrolyte layer, and a cathode layer supported by the metal support plate, the electrochemically active cell region 307 facing the separator plate 315 of the adjacent cell unit.

[0126] The metal support plate has a porous region (not shown) surrounded by a non-porous region, and the overlapping layers of electrochemically active cell regions are deposited on the porous region so that gas can access the active layer coated thereon by passing through holes from one side of the metal support plate 305 to the other. As discussed in WO 2020 / 126486 A1, the porous region includes a small opening (a hole drilled through the metal foil substrate) (not shown) extending through the metal support plate of the cell layer 305 and is positioned to cover the anode (or cathode, depending on the polarity orientation of the electrochemically active cell region 307) located on the metal support plate of the cell layer 305 (the planar area covered by each electrochemically active cell layer is known as the “active cell region”). In a preferred embodiment, the anode (fuel electrode) layer is located adjacent to a porous region having a (sealed) fluid volume in the fuel cell unit 301, which includes a fluid port 316 and thus a fuel flow volume supplied by fuel entering and exiting through the fuel port 316. The cathode (air electrode) layer is located on the opposite side of the electrochemically active cell region 307, i.e., its outer surface, and is exposed to air flowing across it during use of the fuel cell unit 301 (a perforated, porosity-adjusted metal substrate is preferred, but the present invention is also applicable to metal substrates with other porosities, such as porous metal foam or porous tape-cast metal substrates).

[0127] The cell layer 305 and the separator plate 315 are each (oxidizing agent Oh Fluid port 306 provided on the plate (for fuel / or other purposes) Oh The spacer plate 310 has a 316 and is positioned toward the center of the opposing edges of the cell unit 301 and on the opposing side of the electrochemically active layered region 307. The spacer plate 310 has an opening port that allows fluid communication between the fluid ports 306, 316, and the first fluid volume provided between the metal support plate 305 and the separator plate 315 is defined by the spacer plate 310.

[0128] As shown in Figure 3, each cell unit 301 includes three plates or layers, with a spacer plate 310 sandwiched between the cell layer 305 and the separator plate 315 (however, it may also include only two plates or layers, and one or both of the metal support plate 305 and the separator plate 315 may include flanged peripheral features projecting toward the other of the metal support plate 306a and the separator plate 306b, thus eliminating the need for the spacer plate 310, as will be explained in more detail with respect to Figure 4).

[0129] The cell layer 305, spacer 310, and separator plate 315 are stacked on top of each other and welded (fused) around their periphery to form a single metal-supported repeat cell unit 301a having a first fluid volume in the center defined by the space provided by the spacer plate 310. Each of the cell layer 305, spacer 310, and separator plate 315 is a self-supporting metal plate and can be handled as separate plates before welding or fusion. The metal components of the cell stack repeat layer 301a are in electrical contact with each other, and the flow of electrons between them occurs mainly through fuse / weld paths, thereby avoiding loss of contact resistance between surfaces.

[0130] The stack of cell units 301 in Figure 3 is stacked with gaskets 320 placed between adjacent cell units 301. Each gasket 320 surrounds the fluid ports 306, 316 of the cell unit 301 and is electrically insulated. The stacks of cell units 301, each with its own gasket 320, are stacked on top of each other such that the corresponding fluid ports 306, 316 in the cell unit 301 are aligned to form an internal manifold or chimney through the stack of cell units, through which fluid can be supplied to and discharged from the cell units (specifically, the opening between the cell layer 305 and the separator plate 315 of each cell unit 301). The gaskets 320 provide a fluid seal between their surface and that of adjacent surfaces. The gaskets 320 are shown as pre-formed gaskets, but may also be formed in place. The gaskets are not conductive. Gaskets can be made from, for example, vermiculite (or thermiculite), which offers superior sealing performance compared to mica or ceramic, while requiring a much lower load for sealing.

[0131] The separator plate is provided with a 3D region that includes dimple-like protrusions and varying midplane heights. In the 3D region, upward and downward dimple-like protrusions are provided to extend from the midplane region to the cell layer 305 of its own cell unit 301a (e.g., on the opposite side of the metal support plate supporting the electrochemically active cell region 307) and from the midplane region to the cathode (or anode, depending on the polarity orientation of the electrochemically active layer) of a subsequent (or adjacent) cell unit 301b stacked beneath this cell unit 301a. In this example, since the 3D region of the separator plate 315 completely covers the electrochemically active cell layer 305, the midplane height can be appropriately adjusted over the entire electrochemically active cell region 307. However, if, for example, the upstream or downstream end of the active cell region does not need to use height to influence the fluid flow, the midplane height of the 3D region does not need to be varied over the entire electrochemically active cell region. The 3D region can optionally extend beyond the active cell region 307 and can optionally have the height of an intermediate plane adjusted to influence the fluid flow upstream or downstream of it.

[0132] The separator plate 315 is formed from a sheet (e.g., a metal sheet). The intermediate planar region is part of the sheet between the dimple-like protrusions. In Figure 3, the intermediate planar region includes three intermediate planar sub-regions, each of which is a flat plane, and the intermediate planar sub-regions are separated from each other by their respective steps. However, the intermediate plane (and its sub-regions) does not have to be flat (as illustrated, for example, with reference to Figure 4). The dimple-like protrusions are distributed across the area of ​​the separator plate 315 corresponding to the area of ​​the electrochemically active cell region 307. In other words, the dimple-like protrusions have a similar area to the electrochemically active cell region and are located beneath it. The dimple-like protrusions may have an area equivalent to that of the active cell region 307, and their centers coincide with those of the active cell region 307. The dimple-like protrusions may be arranged alternately across the separator plate 315 (between upward and downward), and typically there are an equal number of "upward" and "downward" protrusions in a given area. In other words, the nearest neighbor of a given "upward" protrusion is usually a "downward" protrusion (and vice versa). As a result, the dimple-like protrusions 330 and 335 electrically connect adjacent cell units 301 of the stack and connect the electrochemically active cell regions 307 of the stack (usually one per cell unit) in series with each other.

[0133] The distance between the cell layer 305 and the intermediate plane of the separator plate 315 changes across the 3D region due to changes in the intermediate plane region. The height of the upward and downward dimple-like protrusions changes in response to changes in the intermediate plane region of the separator plate 315 (explained in more detail below). Regardless of the individual dimensions of the different protrusions, it will be understood that the overall height (thickness) of the interconnection, i.e., the height from the bottom of the downward protrusion to the top of the upward protrusion, is always the same.

[0134] The dimple-like protrusions and the changing intermediate planar regions are formed by deforming or pressing a metal plate to form 3D regions. The deformation / pressing may be any suitable method for forming the sheet into the desired configuration, such as hydroforming or stamping / pressing. Thus, a single thin sheet can be deformed into a separator plate 315. As a result of pressing, dimple-like protrusions extending outward on one side of the separator plate 315 form cavities on the other side of the separator plate 315. Those skilled in the art will understand that the height of the features formed by pressing is limited by the material properties and thickness of the metal sheet. However, in this case, the height of the pressed features is relatively small (usually a maximum of 1 mm), and the mechanical strength of the metal plate deformed by pressing is not significantly reduced.

[0135] Figures 3B and 3C show the separator plate 315 of Figure 3A in perspective and plan view, respectively. Figure 3C also shows sections AA, BB, and CC of the separator plate 315. In the figures, the thickness (vertical direction) dimension of the dimple-like protrusions, and therefore the height, is exaggerated for illustrative purposes.

[0136] The first set of dimple-like protrusions 330, 331, 332 extend outward (upward in Figure 3) from the intermediate planar region of the separator plate 315 toward the cell layer 305 (and its metal support plate) of the cell unit 301a on which the separator plate is located. The outermost points of the first dimple-like protrusions 330, 331, 332 contact the cell layer 305 of the cell unit 301a on which the separator plate is located. As a result, the first dimple-like protrusions 330, 331, 332 (together with the spacer plate 310) define a first fluid volume between the cell layer 305 and the intermediate planar region (on the first side) of the separator plate 315.

[0137] The second set of dimple-like protrusions 335, 336, and 337 extend outward (downward in Figure 3) from the intermediate planar region of the separator plate 315 (of cell unit 301a) toward the cell layer 305 of the adjacent cell unit 301b (i.e., the cell unit adjacent to the cell unit on which the separator plate 315 is located). In other words, the dimple-like protrusions 330, 331, and 332 extend outward from the first side of the separator plate, while the dimple-like protrusions 335, 336, and 337 extend outward from the second side of the separator plate. The outermost points of the dimple-like protrusions 335, 336, and 337 contact the electrochemically active cell region 307 of the adjacent cell unit 301b. As a result, the dimple-like protrusions 335, 336, and 337 define a second fluid volume between the intermediate plane (second side) of the separator plate 315 and the electrochemically active layer 307 of the adjacent cell unit 301b.

[0138] The midplane of the separator plate 315 changes in height across the active cell region 307, and the dimple-like protrusions also change in height accordingly (so that their outermost points form a plane). Figure 3 shows a midplane with three different heights of midplane sub-regions 340, 341, and 342, with steps between each midplane sub-region. In this case, each midplane sub-region is itself a flat plane. Although Figure 3 shows three different midplane heights as merely an example, it will be understood that there may be more than two or three midplane heights. The dimple-like protrusions 330 project upward from the first midplane sub-region 340. The dimple-like protrusions 330 of the first midplane sub-region 340 extend outward from the separator plate 315 toward the cell layer 305 of the cell unit 301a in which the separator plate is located. The outermost points of the dimple-shaped protrusions 330 define a plane that is parallel to and in contact with the cell layer 305 (as a result, the dimple-shaped protrusions 330 of the first intermediate plane sub-region 340 have the same height as the thickness of the spacer plate 310). In this case, each intermediate plane sub-region of the separator plate is a flat (uncurved) plane parallel to the cell layer 305. However, this is not necessarily the case (see, for example, Figure 4).

[0139] The dimple-like projections 335 protrude downward from the first intermediate plane sub-region 340. The dimple-like projections 335 of the first intermediate plane sub-region 340 extend outward from the separator plate 315 toward the cell layer 305 of the cell unit 301b adjacent to the one containing the separator plate 305. The outermost point of the dimple-like projections 335 is parallel to the cell layer 305 (of the electrochemically active cell region 307) of the adjacent cell unit 301b, defining a contact plane.

[0140] The dimple-shaped projection 331 protrudes upward from the second intermediate plane sub-region 341, and the dimple-shaped projection 336 protrudes downward from the second intermediate plane sub-region 341. The second intermediate plane sub-region 341 of the separator plate 315 is closer to the cell layer 305 of the cell unit on which the separator plate is located than the first intermediate plane sub-region 340. Therefore, the dimple-shaped projection 331 is shorter than the dimple-shaped projection 330 (so that the outermost points of these projections 330 and 331 are located in a plane parallel to the cell layer 305), and the dimple-shaped projection 336 is longer than the dimple-shaped projection 335 (so that the outermost points of these projections 335 and 336 are located in a plane parallel to the cell layer 305).

[0141] The dimple-shaped projection 332 protrudes upward from the third intermediate plane sub-region 342, and the dimple-shaped projection 337 protrudes downward from the third intermediate plane sub-region 342. The third intermediate plane sub-region 342 of the separator plate 315 is closer to the cell layer 305 of the cell unit 301a on which the separator plate 315 is located than the second intermediate plane sub-region 341 (and also closer than the first intermediate plane sub-region 340). Therefore, the dimple-shaped projection 332 is shorter than the dimple-shaped projection 331 (so that the outermost points of the dimple-shaped projections 330, 331, and 332 are located in a plane parallel to the cell layer 305), and the dimple-shaped projection 337 is higher than the dimple-shaped projection 336 (so that the outermost points of the dimple-shaped projections 335, 336, and 337 are located in a plane parallel to the cell layer 305).

[0142] The height of the first fluid volume as it changes is defined between the midplane region and the outermost points of the dimple-shaped protrusions 330, 331, and 332. The height of the second fluid volume as it changes is defined between the midplane sub-region and the outermost points of the dimple-shaped protrusions 335, 336, and 337. The height of the first fluid volume is highest in the first midplane sub-region 340, lowest in the second midplane sub-region 341, and lowest in the third midplane sub-region 342. Correspondingly, as the changing midplane is formed by pressing, the height of the second fluid volume is lowest in the first midplane sub-region 340, highest in the second midplane sub-region 341, and highest in the third midplane sub-region 342. As can be seen in sections AA, BB, and CC, the sum of the first and second fluid volume heights is the same in each intermediate plane sub-region (first intermediate plane sub-region 340, second intermediate plane sub-region 341, and third intermediate plane sub-region 342).

[0143] The change in height of the first fluid volume is perpendicular to the line between the first fluid ports 316 (and therefore, in this example, perpendicular to the overall flow direction within the first fluid volume (the overall flow direction within the second fluid volume may be the same as that of the first fluid volume, in which case the first and second fluids are in a coflow configuration)). One end of the fluid port 316 is an inlet port for supplying the first fluid to the first fluid volume, and the other end of the fluid port 316 is an outlet for discharging the first fluid from the first fluid volume. The first fluid flows within the first fluid volume, generally from the inlet to the outlet. The height of the first fluid volume is lowest in the third intermediate plane sub-region 342. This restricts the flow of the first fluid between the inlet port and the outlet port 316 (with respect to the second and first intermediate plane sub-regions 341 and 340, respectively), ensuring that a portion of the first fluid is forced to follow a longer path from the inlet port to the outlet port across the second intermediate plane sub-region 341. Similarly, the second intermediate plane sub-region 341 provides a restriction (in a smaller area than the third intermediate plane sub-region 342) that ensures a second portion of the first fluid is forced to follow a longer path from the inlet port to the outlet port across the first intermediate plane sub-region 340. Thus, the change in the height of the first fluid volume promotes uniform distribution of the first fluid across the entire area covered by the dimple-like protrusions and the active cell region 307. The dimple-like protrusions enable mixing of the first fluid, and the intermediate plane sub-regions allow control over the distribution of the first fluid.

[0144] In the example shown in Figure 3, the cell unit 301 does not have a fluid port for the second fluid. In this case, the second fluid volume is collected and distributed externally by a manifold, and the second fluid is supplied to the second fluid volume by a passage located beyond the edge of the cell unit 301 as shown in Figure 3. The second fluid is supplied by at least one inlet passage and discharged by at least one outlet passage. In some cases, the second fluid inlet and outlet passages are located at opposing edges of the cell unit 301 (e.g., Figure 10, configurations 1015, 1020). In some cases, a fluid port for the second fluid (not shown in Figure 3) is provided in the center of the plan view area of ​​the cell unit, which may also be an inlet port, in which case passages that collect at the manifold outside the outlet are provided at at least one pair of opposing cell edges (e.g., Figure 10, configurations 1005, 1010).

[0145] Changes in the height of the second fluid volume affect the flow of the second fluid within that volume. Similar to the first fluid volume, a lower height in the second fluid volume imposes restrictions compared to a higher height, causing the second fluid to preferentially flow towards areas of greater height.

[0146] In the example shown in Figure 3, the first intermediate plane sub-region 340 is located midway between the outermost points of the dimple-shaped protrusions 330 and 335, but this is not required. The height of the first fluid volume may be lower than the height of the second fluid volume. The first fluid volume may have a height between 30% and 80%, preferably between 40% and 60%, of the height of the second fluid volume.

[0147] In laminar flow between two plates separated by a height h, the maximum flow velocity (at the midpoint between the two plates) is h. 2It is proportional to the flow rate. The same relationship holds for the flow rate between the inlet and outlet ports. The flow rate is higher in the volume portion with greater height and lower in the volume portion with less height (in other words, for the flow rate between the inlet and outlet ports, the flow rate in a portion of the volume can be increased by making that portion of the volume higher, and conversely, the flow rate in a portion of the volume can be decreased by making that portion of the volume lower. For example, when the distance between two plates changes in a direction perpendicular to the straight line between two ports (e.g., the two ports in Figure 3), the change can make the flow rate along a straight channel (or streamline) between the ports the same (or similar) as the flow rate along a less straight channel (or streamline). In other words, the change can make the flow rate in the first fluid volume the same throughout the region enclosed by the first intermediate plane sub-region 340, the second intermediate plane sub-region 341, and the third intermediate plane sub-region 342. Thus, by changing the intermediate plane height, the distribution of the first fluid across the electrochemically active cell region can be improved.

[0148] In a preferred example, the first fluid is fuel and the second fluid is air or an oxidizer, with the height of the first fluid volume being smaller than the height of the second fluid volume (in the case of air or an oxidizer). In operation as an SOFC, the fuel (in gaseous form) is typically supplied at a higher pressure than the oxidizer (also in gaseous form), and the height of the fuel volume is lower than the height of the oxidizer volume. As a result, changes in the midplane (i.e., changes in the height of each volume) have a greater impact on the fuel volume than on the oxidizer volume. For this reason, changes in the midplane height can be preferentially adjusted for the first fluid (fuel, etc.) rather than the second fluid (oxidizer, etc.). For example, this embodiment helps distribute (higher pressure) fuel to the outer edge regions of the cell (region 340) furthest from the ports (located in the center) (these are the places where it is most difficult to supply fuel with a limited number of ports), while simultaneously promoting / distributing more airflow to the central region 342 of the cell, which is generally the hottest part of the cell, thereby providing more cooling and an improved cell thermal profile (i.e., smoother / flatter). By deforming the separator, the height of each fluid volume increases or decreases accordingly, allowing for optimal utilization of this inverse correlation / requirement.

[0149] The dimple-like protrusions 330, 331, 332, 335, 336, and 337 in this example have a circular cross-section. They do not direct the first and second fluids in any particular direction, thus allowing for the distribution of the first and second fluids over the electrochemically active cell region 307. Therefore, the flow paths around the dimple-like protrusions can be described as meandering. The dimple-like protrusions are substantially frustoconical in shape, having non-vertical sidewalls and a truncated flat top (referred to above as the outermost point). They may have cross-sectional shapes other than circular, such as square, cruciate, or hexagonal, and do not control the direction of the surrounding fluid flow in their respective fluid volumes. To avoid restricting flow in any particular direction, they may have elongated shapes such as elliptical, rectangular, or non-regular polygonal shapes with an aspect ratio of less than 10, preferably less than 5, and more preferably less than 2. The dimple-like protrusions are press-fitted into the plate of the separator plate 315. Such inclined walls are preferable to vertical walls because they allow for easier angle formation when the separator plate 315 is pushed out from the plate in which it is formed. However, any angle between 20 and 90 degrees may provide a usable shape. Preferably, the angle is between 40 and 90 degrees from the plane of the sheet being pressed.

[0150] Each step between intermediate plane sub-regions is a separate step, and in this case too, as shown in Figure 3, it may have angled (non-vertical) side walls. Such inclined walls are a preferred configuration because they are easier to angle than vertical walls when the separator plate 315 is pushed out of the plate in which it is formed. However, any angle from 20 to 90 degrees can probably provide a usable shape. Preferably, it is between 40 and 90 degrees from the plane of the sheet being pressed.

[0151] Typically, the upwardly projecting dimple-like protrusions 330, 331, and 332 and the downwardly projecting dimple-like protrusions 335, 336, and 337 are pressed in the same step as the intermediate planar sub-regions 340, 341, and 342 are pressed. The first intermediate planar sub-region 340 may represent an undeformed area of ​​the planar metal sheet on which the separator plate 315 is formed.

[0152] Compressive forces within the stack near the active cell region 307 are necessary for good electrical contact and therefore good conductivity through the stack. Dimpled protrusions 330, 331, and 332 (towards the cell layer 305 of cell unit 301a where the separator plate 315 is located), as well as dimpled protrusions 335, 336, and 337 (away from the cell layer 305 of cell unit 301a where the separator plate 315 is located, towards the cell layer 305 of the adjacent cell unit 301b), form the necessary electrical contacts between cell units 301 in the stack and also provide support for the fuel cell unit in the central region. The dimpled protrusions are arranged with alternating upward and downward dimpled protrusions (towards and away from the cell layer 305 of cell unit 301a where the separator plate is located), transmitting compressive forces through the stack (to the cell layer of the cell unit where the separator plate is located and to the cell layer of the adjacent cell unit). It will be understood that, as long as there are enough dimple-like protrusions in each direction to transmit compressive force and maintain the first and second fluid volumes without causing excessive distortion in the separator plate and cell layer, the dimple-like protrusions do not need to be strictly arranged in alternating upward and downward directions.

[0153] Referring to Figure 4A, an exploded view of a stack configuration 400 having a separator plate 415 is shown. Figure 4B shows a plan view of the separator plate 415, and Figure 4C shows the cross sections AA, BB, CC, and DD shown in Figure 4B. The cell unit in Figure 4 has a cell layer 405 and a separator plate 415 with a lateral port configuration similar to that in Figure 3. However, the separator plate 415 in Figure 4 is provided with a flanged peripheral feature 410, eliminating the need for the spacer plate 310 in Figure 3. The flanged peripheral feature 410 extends from the first intermediate plane 440 of the separator plate 415 toward the cell layer of the cell unit in which the separator plate is placed, forming a recess (with a convex portion on the outer surface) in the separator plate. The recess forms a first fluid volume within the cell unit during assembly of the cell unit. Although the flanged peripheral feature 410 is shown only on the separator plate 415, it may also be formed on the cell layer, or on both the separator plate and the cell layer. The cell layer 405 and the separator plate 415 are stacked on top of each other and welded (fused) around the flanged peripheral feature 410 to form a single metal-supported repeat cell unit 401a having a first fluid volume in the center defined by the space provided by the flanged peripheral feature. Each of the cell layer 405 and the separator plate 415 is a self-supporting metal plate and can be handled as separate plates before welding or fusion. The metal components of the cell stack repeat layer 401a are in electrical contact with each other, and the flow of electrons between them occurs mainly through fuse / weld paths, thereby avoiding loss of contact resistance between surfaces.

[0154] The separator plate 415 has formed port features 450 that surround the port 316 and extend toward the cell layer 405, with their outermost points forming a flat plane with the outer surface of the flanged peripheral feature 410. The formed port features have a circular cross-section, angled sidewalls, and a cut-off flat top (similar to a dimple-like projection). During compression of the stack of cell units, the outermost points (flat tops) of the formed port features (and flanged peripheral feature 410) contact the cell layer, thereby supporting the compression of the cell stack and transmitting the compressive force to the gasket 320, providing a fluid seal between its surface and the adjacent surface. The first fluid can enter and exit the first fluid volume through the gap between the formed port features 450.

[0155] Similar to the separator plate 315 in Figure 3, the separator plate 415 in Figure 4 is provided with dimple-like protrusions extending toward and away from the cell layer 405 over an area corresponding to the active cell region 307. The dimple-like protrusions 430 extend from a first region 440 of the separator plate 415 toward the cell layer 405 of the cell unit 401a in which the separator plate is located. The outermost point of the dimple-like protrusions 430 forms a plane that coincides with the outermost points of the formed port feature 450 and flanged peripheral feature 410 (only when the flanged peripheral feature is formed on the separator plate; in any case, the height of the dimple-like protrusions 430 is the same as the total height of the flanged peripheral feature formed on the separator plate and / or cell layer).

[0156] The dimple-shaped protrusions 435 extend from the first region 440 of the separator plate 415 toward the cell layer 405 of the adjacent cell unit 401b (and away from the cell layer 405 of the cell unit 401a on which the separator plate is located). The outermost points of the dimple-shaped protrusions 435 form a plane.

[0157] The height of the intermediate plane of the separator plate 415 varies across the active cell region 307. In this case, the height change is not stepwise but gradual or smooth, forming a curved intermediate plane. Figure 4 shows how the height of the intermediate plane gradually changes in the second region 443 of the separator plate. The height of the intermediate plane gradually changes in a direction roughly perpendicular to the straight line between the first fluid ports 316. This change causes the height of the first fluid volume to decrease along the straight line between the first fluid ports 316 and gradually increase as it moves away from that line (sections AA, BB). Correspondingly, the change causes the height of the second fluid volume to increase along the straight line between the first fluid ports 316 and gradually decrease as it moves away from that line (sections AA, BB). The effect on the first and second fluid flow paths through the respective first and second fluid volumes is the same as described above with respect to Figure 3.

[0158] As shown in Figure 4, the gentle curvature of the midplane is only in a direction roughly perpendicular to the line between the first fluid ports 316. At the beginning and end of the second midplane sub-region 443, there are steps in the midplane in a direction parallel to its straight line.

[0159] The dimple-shaped protrusions 433 extend from the second intermediate plane sub-region 443 toward the cell layer 405 of the cell unit 401a where the separator plate is located. The outermost point of the dimple-shaped protrusions 433 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 430 of the first intermediate plane sub-region 440.

[0160] The dimple-shaped protrusions 438 extend from the second intermediate plane sub-region 443 of the separator plate 415 toward the cell layer 405 of the adjacent cell unit 401b (and away from the cell layer 405 of the cell unit 401a on which the separator plate is located). The outermost point of the dimple-shaped protrusions 438 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 435 of the first intermediate plane sub-region 440.

[0161] Figure 4 also shows an active cell region 307 in which the electrochemically active cell region is wrapped around the fluid port 306 in order to increase the proportion of the electrochemically active cell unit area and thereby increase the power density of the stack of cell units. In other words, near the port, the edge of the active cell region is shaped to match the shape of the port, and in this case, since the port is circular, the edge of the active cell region forms a concentric subcircle with the port. The edge of the active cell region 307 is spaced away from the edge of the port to ensure space for the formed port feature 450 and the gasket 320 positioned around the port.

[0162] Similar to the features on separator plate 315, the features on separator plate 415 are formed by pressing. The dimple-like protrusions 430, 433, 435, and 458, the varying intermediate planar sub-regions 440, 443, the formed port feature 450, and the flanged peripheral feature 410 can each be formed from a planar sheet by one or more pressing steps.

[0163] Figure 5 shows a plan view of an exemplary separator plate 515 and the cross-sections AA and BB shown therein. Separator plate 515 is similar to the separator plate described above, but has four ports 316a, 316b for a first fluid and a single port 518 for a second fluid. It will be understood that the cell layer used with separator plate 515 has four corresponding ports for the first fluid and a single port for the second fluid. Preferably, the first fluid is a fuel and the second fluid is an oxidizer.

[0164] The two first fluid ports 316a are positioned midway along the width of the separator plate 515, facing the opposing short edges of the separator plate. The two first fluid ports 316b are positioned midway along the length of the separator plate 515, facing the opposing long sides of the separator plate. Either the two first fluid ports 316a are inlet ports and the two first fluid ports 316b are outlet (discharge) ports, or the two first fluid ports 316a are outlet (discharge) ports and the two first fluid ports 316b are inlet ports. The first fluid ports 316a and 316b deliver and discharge the first fluid to a first fluid volume enclosed between the separator plate 515 and the cell layer. Thus, the first fluid in the first fluid volume flows from the inlet port (one of 316a and 316b) to the outlet port (the other of 316a and 316b). Each first fluid port 316 has a formed port feature 450 similar to those described above.

[0165] The second fluid port 518 is positioned midway along the length and width of the separator plate 515 (i.e., in the center of the separator plate 515). Around the second fluid port is a flange configured to contact the cell layer (of the same cell unit to which the separator plate 515 belongs). During the manufacture of the cell unit, a fluid seal is formed between the flange and the cell layer (e.g., by welding around the flange).

[0166] The second fluid port 518 is used to deliver or discharge a second fluid to or from a second fluid volume between the separator plate 515 of a cell unit and the cell layer of an adjacent cell unit. The second fluid volume is also collected externally by a manifold (in the same manner as described above). Preferably, the second fluid port 518 is an inlet port for delivering the second fluid to the second fluid volume, and the discharge from the second fluid volume is collected externally by a manifold, for example at two opposing edges of the separator plate 515.

[0167] The height of the intermediate plane of the separator plate 515 of the cell unit varies across the active cell region. That is, the distance between the intermediate plane of the separator plate 515 and the cell layer of the cell unit in which the separator plate is located changes. In this case, as with the separator plate 315, the height change is stepwise. The height of the intermediate plane changes in a direction approximately perpendicular to the straight line between the first fluid port, which functions as an inlet, and the first fluid port, which functions as an outlet. This change causes the height of the first fluid volume to decrease along the straight line between the inlet and outlet first fluid ports 316a and 316b, and to increase as it moves away from that line. Correspondingly, this change causes the height of the second fluid volume to increase along the straight line between the inlet and outlet first fluid ports 316a and 316b, and to decrease as it moves away from that line. The effect on the first and second fluid flow paths through the respective first and second fluid volumes is the same as described above with respect to Figures 3 and 4.

[0168] Figure 5 shows two different mid-plane sub-regions. The first mid-plane sub-region 540 is positioned along a straight line between the inlet and outlet first fluid ports 316a, 316b. The second mid-plane sub-region 541 is positioned toward the corners and center of the separator plate 515. The first mid-plane sub-region 540 is closer to the cell layer of the cell unit in which the separator plate is positioned than the second mid-plane sub-region 541. As a result, the height of the first fluid volume is greater in the second mid-plane sub-region 541 than in the first mid-plane sub-region 540, and the first fluid is encouraged to be distributed across the first and second mid-plane sub-regions.

[0169] The dimple-like projections 430 extend from the first intermediate planar sub-region 540 of the separator plate 515 toward the cell layer of the cell unit in which the separator plate is located. The outermost point of the dimple-like projections 430 forms a plane that coincides with the outermost points of the formed port feature 450 and flanged peripheral feature 410 (when the flanged peripheral feature is formed only on the separator plate; if the flanged peripheral feature is formed at least partially on the cell layer, the height of the dimple-like projections 430 is the same as the total height of the flanged peripheral feature).

[0170] The dimple-shaped protrusions 435 extend from the first intermediate planar sub-region 540 of the separator plate 515 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost points of the dimple-shaped protrusions 435 form a plane.

[0171] The dimple-shaped protrusions 431 extend from the second intermediate plane sub-region 541 of the separator plate 515 toward the cell layer of the cell unit in which the separator plate is arranged. The outermost point of the dimple-shaped protrusions 431 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 430 of the first intermediate plane sub-region 540.

[0172] The dimple-shaped protrusions 436 extend from the second intermediate plane sub-region 541 of the separator plate 515 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost point of the dimple-shaped protrusions 436 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 435 of the first intermediate plane sub-region 540.

[0173] Figure 6 shows a plan view of an exemplary separator plate 615 and the cross-sections AA and BB shown therein. Separator plate 615 is similar to the separator plate described above, particularly that of Figure 4, but the shape of the separator plate is hexagonal rather than rectangular. It will be understood that the cell layer used with separator plate 615 is correspondingly hexagonal in shape. In this case, the cell layer is an electrolyte-supported polymer electrolyte membrane (PEM). Separator plate 615 comprises, as described above, a first fluid port 316 (one end being an inlet to the first fluid volume and the other end being an outlet from the first fluid volume), a formed port feature 450, and a flanged peripheral feature 410. It will be understood that the changing intermediate plane can also be used for cell units having planar shapes other than rectangles and hexagons, such as circles, triangles, squares, and polygons with more sides.

[0174] The height of the intermediate plane of the separator plate 615 varies across the active cell region. That is, the distance between the intermediate plane of the separator plate 615 and the cell layer of the cell unit in which the separator plate is located changes. In this case, as with the separator plate 415, the change in height is gradual. The height of the intermediate plane changes in a direction approximately perpendicular to the straight line between the first fluid port, which functions as an inlet, and the first fluid port, which functions as an outlet. This change causes the height of the first fluid volume to decrease along the straight line between the inlet and outlet first fluid ports 316 and to increase as it moves away from that line. Correspondingly, this change causes the height of the second fluid volume to increase along the straight line between the inlet and outlet first fluid ports 316 and to decrease as it moves away from that line. The effect on the first and second fluid flow paths through the respective first and second fluid volumes is the same as described above with respect to Figures 3 to 5.

[0175] Figure 6 shows two different mid-plane sub-regions. The first mid-plane sub-region 440 is positioned toward the edge of the separator plate. The second mid-plane sub-region 443 is positioned toward the center of the separator plate 615. The second mid-plane sub-region 443 is a curved plane similar to that in Figure 4. The second mid-plane sub-region 443 is closer to the cell layer of the cell unit in which the separator plate 615 is positioned than the first mid-plane sub-region 440. The curvature of the second mid-plane sub-region 443 is such that the distance between the mid-plane of the separator plate 615 and the cell layer gradually increases as it moves away from the center of the separator plate 615. As a result, the height of the first fluid volume is greater in the first mid-plane sub-region 440 than in the second mid-plane sub-region 443, and the first fluid is encouraged to be distributed across the first and second mid-plane sub-regions.

[0176] The dimple-like projections 430 extend from the first intermediate planar sub-region 440 of the separator plate 615 toward the cell layer of the cell unit in which the separator plate is located. The outermost point of the dimple-like projections 430 forms a plane that coincides with the outermost points of the formed port features 450 and flanged peripheral features 410 (only when flanged peripheral features are formed on the separator plate; in any case, the height of the dimple-like projections 430 is the same as the total height of the flanged peripheral features formed on the separator plate and / or cell layer).

[0177] The dimple-shaped protrusions 435 extend from the first intermediate planar sub-region 440 of the separator plate 615 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost points of the dimple-shaped protrusions 435 form a plane.

[0178] The dimple-shaped protrusions 433 extend from the second intermediate plane sub-region 443 of the separator plate 615 toward the cell layer of the cell unit in which the separator plate is arranged. The outermost point of the dimple-shaped protrusions 433 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 430 of the first intermediate plane sub-region 440.

[0179] The dimple-shaped protrusions 438 extend from the second intermediate plane sub-region 443 of the separator plate 615 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost point of the dimple-shaped protrusions 438 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 435 of the first intermediate plane sub-region 440.

[0180] Figure 7 shows a perspective view of an exemplary separator plate 715. Separator plate 715 is similar to the separator plate described above, particularly that of Figure 4, but separator plate 715 has four first fluid ports. It will be understood that the cell layer used with separator plate 715 is provided with corresponding first fluid ports. In this case, the cell layer includes an electrochemically active region supported (or deposited on and supported) by a metal support plate that is inherently porous (rather than a drilled non-porous metal substrate). Such a porous metal support plate can be produced by tape casting and sintering. Separator plate 715 is provided with formed port features 450 surrounding the ports and flanged peripheral features 410, as described above.

[0181] The separator plate 715 is provided with four first fluid ports 716, 717, each port positioned toward each corner of the separator plate 715. Each of the fluid ports 716, 717 is in fluid communication with a first fluid volume (between the separator plate 715 and the cell layer of the cell unit on which the separator plate is located). Two fluid ports 716 are located at the corners of the separator plate 715 that share the edge of the separator plate 715, and two fluid ports 717 are located at the corners of the separator plate 715 that share the opposite edge of the separator plate 715. The two fluid ports 716 are inlets to the first fluid volume, and the two fluid ports 717 are outlets from the first fluid volume. Thus, the first fluid is introduced into the first fluid volume by the fluid ports 716 and discharged from the first fluid volume by the fluid ports 717.

[0182] The height of the intermediate plane of the separator plate 715 varies across the active cell region. That is, the distance between the intermediate plane of the separator plate 715 and the cell layer of the cell unit in which the separator plate is located changes. In this case, as with the separator plate 415, the change in height is gradual. The height of the intermediate plane varies in a direction roughly perpendicular to the flow direction of the first fluid in the first fluid volume between the first fluid port 716, which functions as an inlet, and the first fluid port 717, which functions as an outlet. The height of the intermediate plane is greater along a line from the midpoint between the two inlet ports 716a and 716b to the midpoint between the two outlet ports 717a and 717b than between ports 716a and 717a (and similarly, between ports 716b and 717b). Correspondingly, this change causes the height of the second fluid volume to increase along the straight line between the inlet and outlet first fluid ports 716a and 717b (and similarly between 716b and 717b), and then decrease away from that straight line toward a straight line from the midpoint between the two inlet ports 716a and 716b toward the midpoint between the two outlet ports 717a and 717b. The effect on the first and second fluid flow paths through the respective first and second fluid volumes is the same as described above with respect to Figures 3 to 6.

[0183] Figure 7 shows two different intermediate plane sub-regions. The first intermediate plane sub-region 440 is positioned toward two opposing edges of the separator plate (the edges between ports 716a and 717a, and between 716b and 717b, i.e., the long edges in this case). The second intermediate plane sub-region 443 is positioned toward the center of the separator plate 615. The second intermediate plane sub-region 443 is a curved plane similar to those in Figures 4 and 6. As previously described, dimple-like protrusions 430 and 435 are provided in the first intermediate plane sub-region 440, and dimple-like protrusions 433 and 438 are provided in the second intermediate plane sub-region.

[0184] Figure 8 shows a perspective view of an exemplary separator plate 815. Separator plate 815 is similar to the separator plate described above, particularly that of Figure 4, but separator plate 815 has three first fluid ports. It will be understood that the cell layer used with separator plate 815 is provided with corresponding first fluid ports. Separator plate 815 is provided with formed port features 450 surrounding the ports and flanged peripheral features 410, as described above.

[0185] The separator plate 815 is provided with three first fluid ports 816, 817. The first fluid port 816 is located midway along its edge toward the first short edge of the separator plate 815. The two first fluid ports 817a, 817b are located toward the respective corners of the separator plate 815 along the second edge opposite the first edge. Each of the fluid ports 816, 817 is in fluid communication with a first fluid volume (between the separator plate 815 and the cell layer of the cell unit in which the separator plate is located). The first fluid port 816 may be an inlet port, and the two first fluid ports 817 may be outlet ports. Thus, the first fluid is introduced into the first fluid volume by the fluid port 816, flows through the first fluid volume, and is discharged from the first fluid volume by the second fluid ports 817. Alternatively, the first fluid port 816 may be an outlet port, and the two first fluid ports 817 may be inlet ports. Thus, the first fluid is introduced into the first fluid volume by the two fluid ports 817, flows through the first fluid volume, and is discharged from the first fluid volume by the fluid port 816.

[0186] The height of the intermediate plane of the separator plate 815 varies across the active cell region. That is, the distance between the intermediate plane of the separator plate 815 and the cell layer of the cell unit in which the separator plate is located changes. In this case, as with the separator plate 315, the change in height is stepwise. The height of the intermediate plane changes in a direction roughly perpendicular to the flow direction of the first fluid in the first fluid volume between the first fluid port 816, which functions as an inlet (outlet), and the first fluid port 817, which functions as an outlet (inlet). The height of the intermediate plane (and therefore the height of the first fluid volume) is smaller along the straight lines between ports 816 and 817a and between ports 816 and 817b than elsewhere across the separator plate. The height of the second fluid volume changes accordingly. The effects on the first and second fluid flow paths through the respective first and second fluid volumes are the same as those described above with respect to Figures 3 to 7.

[0187] Figure 8 shows two different intermediate plane sub-regions. The second intermediate plane sub-region 441 is located along the straight lines between ports 816 and 817a, and between ports 816 and 817b. The first intermediate plane sub-region 440 is located elsewhere across the separator plate 815. As previously described, dimple-like protrusions 430, 435 are provided in the first intermediate plane sub-region 440, and dimple-like protrusions 431, 436 are provided in the second intermediate plane sub-region 441.

[0188] Figure 9 shows schematic plan views of further exemplary separator plates 915, 916, 917, 918, and 919. Separator plates 915, 916, 917, 918, and 919 illustrate further first fluid port configurations that can be used with the corresponding varying midplane heights of separator plates 915, 916, 917, 918, and 919. In each case, a relatively high midplane height (high height to the first fluid volume) is represented by a dotted area 340, an intermediate midplane height (intermediate height to the first fluid volume) is represented by a shaded area 341, and a low midplane height (low height to the first fluid volume) is represented by a dashed area 342. In each case, the midplane height may vary in steps or gradually as described above. In each case, the first fluid port communicating with the first fluid volume is represented by a circle 916. The main flow direction is indicated by arrows, which also serve to indicate which port 916 is the inlet port and which is the outlet port. It will be understood that the flow direction across the separator plate can be reversed from the direction indicated by the arrows by swapping the inlet and outlet ports. Note that separator plate 915 is similar to separator plates 315 and 415 for illustrative purposes. Also note that each port configuration shown in Figure 9 (and actually in Figures 7 and 8) can be applied to separator plates having different planar shapes, such as circular, triangular, square, hexagonal (e.g., Figure 6), or other polygons.

[0189] Figure 10 shows a schematic plan view of a preferred layout of the separators and ports (indicated by circles) in the external manifold (if used) for the first and second fluids. For clarity, any second fluid ports are not shown in the diagram of the first fluid port layout, and vice versa. The arrows indicate the general fluid flow direction for the first and second fluids, and thus also indicate whether each port is an inlet or outlet port. It will be understood that the flow direction across the separator plate can also be reversed from the direction indicated by the arrows by swapping the inlet and outlet ports. The height of the midplane of the separator plate is varied to facilitate uniform distribution of the first fluid across the separator plate, as described above, and therefore it will be understood that the arrows are a simplified representation of the first fluid flow path.

[0190] For example, the layout from the side of the first fluid port to the opposite side (similar to Figures 3 and 4) may preferably be accompanied by one of the second fluid layouts 1005, 1010, 1015, and 1020. The second fluid layouts 1005 and 1010 include a central port for a second fluid (similar to Figure 5), and the second fluid can be collected externally by a manifold with a pair of opposing edges of one (1005) or two (1010) separators. The second fluid layouts 1015 and 1020 include a complete external manifold for the second fluid, with flow from one end of separator to the opposite end. Depending on the second fluid layout and the selection of ports as inlets and outlets, it can be seen that various flow conditions can be selected in the layout from the side of the first fluid port to the opposite side. For example, there is reverse flow using the second fluid layout 1015 (where the first and second fluids generally flow in opposite directions), co-flow using the second fluid layout 1015 (with the arrows reversed) (where the first and second fluids generally flow in the same direction), and cross-flow using the second fluid layout 1020 (where the first and second fluids generally flow at 90 degrees to each other).

[0191] In another example, the second fluid layouts 1015 and 1020 are preferably used in conjunction with the first fluid layout from one corner to the opposite corner (as described with reference to Figure 8 above).

[0192] A preferred layout of the second fluid (with respect to a given first fluid layout) is preferred for at least one of thermal management and symmetry throughout the cell unit.

[0193] Typically, the first and second fluids are fuel and oxidizer, respectively, with the fuel usually supplied at high pressure. A layout in which the volume of the second (oxidizer) fluid is higher toward the center of the separator plate (or has a central port for the inlet of the second (oxidizer) fluid) is considered preferable when operated as an SOFC to improve cooling of the hot central portion of the cell unit by the second fluid.

[0194] Figure 11 shows a plan view of an exemplary separator plate 1115 and the cross sections AA, BB, CC, and DD shown therein. The separator plate 1115 is similar to the separator plate described above, particularly the one in Figure 4, but the height of the intermediate plane of the separator plate 1115 changes across the active cell region in a direction roughly parallel to the straight line between the inlet and outlet to the first fluid volume.

[0195] As described above, the separator plate 1115 comprises a first fluid port 316 (one end being an inlet to the first fluid volume and the other end being an outlet from the first fluid volume), a formed port feature 450, and a flanged peripheral feature 410. It will be understood that the changing intermediate plane can also be used for cell units having planar shapes other than rectangles, such as circles, triangles, squares, hexagons, and polygons with more sides.

[0196] The height of the intermediate plane of the separator plate 1115 varies across the active cell region. That is, the distance between the intermediate plane of the separator plate 1115 and the cell layer of the cell unit in which the separator plate is located changes. In this case, as with the separator plate 415, the change in height is gradual. The height of the intermediate plane changes in a direction roughly parallel to the straight line between the first fluid port acting as an inlet and the first fluid port acting as an outlet. This change is such that the height of the first fluid volume is lower near the first fluid port 316a and increases to a maximum near the first fluid port 316b. Since the intermediate plane has the same height around each first fluid port 316, the same type of gasket can be used around each first fluid port 316. This means that there is a step in the intermediate plane between the portion of the intermediate plane that provides the maximum height of the first fluid volume 415 and the nearby first fluid port 316b. In response to this, the change is such that the height of the second fluid volume increases near the first fluid port 316a and decreases to a minimum near the first fluid port 316b.

[0197] Figure 11 shows two different mid-plane sub-regions. The first mid-plane sub-region 440 is positioned toward the edge of the separator plate. The second mid-plane sub-region 1144 is positioned toward the center of the separator plate 1115. The second mid-plane sub-region 1144 is an inclined surface. Near the first fluid port 316a, the second mid-plane sub-region 1144 is at the same distance from the cell layer of the cell unit that the separator plate 1115 is the first mid-plane sub-region 440. The inclination of the second mid-plane sub-region 1144 is such that the distance between the mid-plane of the separator plate 1115 and the cell layer gradually increases as it moves away from the first fluid port 1143 of the separator plate 1115. As a result, the height of the first fluid volume is higher in the second mid-plane sub-region 1144 than in the first mid-plane sub-region 440. The second mid-plane sub-region 1144 is shown as an inclined surface in Figure 11, in other words, the height of the mid-plane region changes as a continuous transition. Alternatively, the second mid-plane sub-region may be realized as a series of step-like sub-regions, in which case the height of the mid-plane region changes as a corresponding number of discontinuous transitions, similar to those described with reference to Figure 3.

[0198] The dimple-like projections 430 extend from the first intermediate planar sub-region 440 of the separator plate 1115 toward the cell layer of the cell unit in which the separator plate is located. The outermost point of the dimple-like projections 430 forms a plane that coincides with the outermost points of the formed port features 450 and flanged peripheral features 410 (only when flanged peripheral features are formed on the separator plate; in any case, the height of the dimple-like projections 430 is the same as the total height of the flanged peripheral features formed on the separator plate and / or cell layer).

[0199] The dimple-shaped protrusions 435 extend from the first intermediate planar sub-region 440 of the separator plate 1115 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost points of the dimple-shaped protrusions 435 form a plane.

[0200] The dimple-shaped protrusions 1134 extend from the second intermediate plane sub-region 1144 of the separator plate 1115 toward the cell layer of the cell unit in which the separator plate is arranged. The outermost point of the dimple-shaped protrusions 1134 forms a plane that coincides with the outermost point of the dimple-shaped protrusions 430 of the first intermediate plane sub-region 440.

[0201] The dimple-shaped projections 1139 extend from the second intermediate plane sub-region 1144 of the separator plate 1115 toward the cell layer of the adjacent cell unit (extending away from the cell layer of the cell unit on which the separator plate is located). The outermost point of the dimple-shaped projections 1139 forms a plane that coincides with the outermost point of the dimple-shaped projections 435 of the first intermediate plane sub-region 440.

[0202] Typically, the separator plate 1115 in Figure 11 may be used such that the first fluid port 316a is the outlet from the first fluid volume and the first fluid port 316b is the inlet to the first fluid volume, and the first fluid in the first fluid volume experiences a relatively high volume near the inlet and a relatively low volume near the outlet. This may improve the utilization of this first fluid by the electrochemically active cell region 307.

[0203] For example, the first fluid volume may be configured for fuel and the second fluid volume for oxidizer. When operating as a fuel cell, with the first fluid port 316a being the inlet to the first fluid volume and the first fluid port 316b being the outlet from the first fluid volume, the fuel utilization rate may increase due to a change in the midplane (a decrease in the height of the first fluid volume from the inlet to the outlet). On the other hand, the second fluid volume can be configured such that the second fluid (e.g., oxidizer) within it flows in the same direction as the first fluid. This is sometimes called co-flow. In such a co-flow configuration, the height of the second fluid volume increases along the second fluid flow path, thereby improving the cooling of the cell unit. Generally, when used as a fuel cell in this way, the height of the first fluid volume may be greater than the height of the second fluid volume across the entire cell area.

[0204] Figure 12 is a cross-sectional plan view of a stack of cell units, the cell units within the stack having a configuration similar to that described with reference to Figure 11. The cross-section shown in Figure 12 passes through the second fluid volume. For clarity, dimples or electrochemically active cell regions are not shown. The plan view installation area of ​​the stack of cell units is represented by the outline of the separator plate 1115. As previously mentioned, the gasket 320 surrounds the first fluid port 316. These gaskets separate the first and second fluid volumes and form part of an internal manifold or chimney that penetrates the stack of cell units, through which the first fluid can be delivered to and discharged from the first fluid volume of the cell unit. The stack of cell units is placed within a housing 1255 that provides a boundary for enclosing the second fluid volume. There is a gap between the stack of cell units and the housing 1255.

[0205] An inlet 1218a to a second fluid volume and an outlet 1218b from the second fluid volume are configured to deliver and discharge the second fluid from the second fluid volume. The second fluid volume may be collected externally by a manifold, in which case the cell unit does not have fluid ports for delivery and / or discharge of the second fluid, or it may be collected internally by a manifold, in which case the inlet 1218a to the second fluid volume and the outlet 1218b therefrom are provided within each cell unit (the installation area of ​​the cell unit represented by 1115 includes the dashed area in Figure 12).

[0206] In this example, each separator plate 1115 has an inlet 316b into the first fluid volume and an outlet 316a from the first fluid volume. Correspondingly, the height of the second fluid volume is configured to increase from an inlet 1218a into the second fluid volume to an outlet 1218b from the second fluid volume.

[0207] During use, the height of the second fluid volume is relatively low near the inlet to the second fluid volume, so the gap between the installation area of ​​the cell unit / stack (represented by 1115 in Figure 12) and the housing 1255 provides a bypass for some of the second fluid delivered by the inlet 1218a to the second fluid volume. Generally, as the height of the second fluid volume increases toward the outlet 1218b from the second fluid volume, the second fluid is drawn out of the gap into the portion of the second fluid volume within the installation area of ​​the cell unit / stack (represented by 1115 in Figure 12). This flow of the second fluid in the second fluid volume is represented by arrow 1260.

[0208] In this example, the first fluid volume can be for fuel and the second fluid volume for oxidizer, and the cell unit can operate as a fuel cell unit. By decreasing the height of the first fluid volume along the flow path of the first fluid volume, fuel utilization may increase. On the other hand, by increasing the height of the second fluid volume along the flow path of the second fluid volume (and bypass as a byproduct), the flow rate of the second fluid in the relatively hot areas of the stack increases (due to co-flow of fuel and oxidizer), improving cooling and enhancing fuel cell performance.

[0209] Figure 13 shows a modified version of the stack cell unit described with reference to Figure 12. The modification in Figure 13 further includes a baffle 1365 that reduces or eliminates the gap between the installation area of ​​the stack of cell units (represented by 1115) and the housing 1255. The baffle 1365 further enhances the bypass effect described with reference to Figure 12 by forcing much or all of the second fluid into the portion of the second fluid volume within the installation area of ​​the cell unit / stack (represented by 1115 in Figure 13). The baffle may be formed of an insulating material such as mica, and the pair of baffles may extend through the height of the housing (i.e., in the stacking direction), and the pair is a separate component from the stack and the housing.

[0210] The separator plate described above may be manufactured by providing a planar metal sheet and deforming the metal sheet to provide a three-dimensional (3D) region. The deformation may be performed by pressing or forming, as previously described. The three-dimensional (3D) region includes at least: a first plurality of outwardly extending dimple-like protrusions defining the height of a first fluid volume on the first side of the separator plate, and a second plurality of outwardly extending dimple-like protrusions defining the height of a second fluid volume on the second side of the separator plate, thereby arranging an intermediate planar sub-region between the protrusions, and the intermediate planar sub-region is formed to selectively change its height in at least one direction across the active cell region such that the respective relative heights of the first and second fluid volumes increase and decrease accordingly as a result.

[0211] Molded port features, flanged periphery features, and / or other molded flow control features can be conveniently formed on the separator plate in the same steps as the intermediate planar regions and protrusions are formed, as described above.

[0212] An electrochemical cell unit can be manufactured by providing a cell layer including a metal support plate that joins a metal support plate and a separator plate, with the first side carrying an electrochemically active cell region and the three-dimensional (3D) region of the separator plate covering the cell layer. The joining can be done by welding the metal support plate and the separator plate together around their periphery. In the manufacture of the cell unit, the first plurality of dimple-like protrusions typically contact the metal support plate (of the cell layer) of the cell unit. When manufacturing the cell unit, the periphery of the cell layer and the separator plate, and any fluid ports provided therein, are typically aligned.

[0213] A stack of electrochemical cell units can be manufactured by stacking multiple electrochemical cell units such that the first side of the separator plate of a first electrochemical cell unit faces the cell layer of the first electrochemical cell unit, enclosing a first fluid volume between them, and the second side of the separator plate of a first electrochemical cell unit faces the cell layer of an adjacent second electrochemical cell unit in the stack of cell units, enclosing a second fluid volume between them. When manufacturing a stack of cell units, the second set of dimple-like protrusions of the first electrochemical cell unit typically contact the cell layer of a second, adjacent electrochemical cell unit (usually the electrochemically active cell region on a metal support plate). When manufacturing a stack of cell units, the periphery of the cell units and any fluid ports provided therein are typically aligned. The aligned fluid ports form fluid passages for supplying and discharging fluid volumes. In the next step, the stack may be housed in a container and an external fluid passage may be provided.

[0214] The present invention is not limited to the examples described above, and other embodiments will be readily apparent to those skilled in the art without departing from the scope of the appended claims.

[0215] These and other features of the present invention are described above merely as examples. Further modifications to the present invention may be made within the scope of the claims.

Claims

1. An electrochemical cell unit, A cell layer containing an electrochemically active cell region, A separator plate including a metal sheet covering the cell layer, It is an electrochemical cell unit that includes, The separator plate has a selectively molded three-dimensional (3D) region that covers at least a portion of the electrochemically active cell region, In that three-dimensional (3D) domain, The metal sheet is deformed into a first set of outwardly extending dimple-like protrusions that define the height of the first fluid volume on the first side of the separator plate. In addition, the metal sheet is deformed into a second set of outwardly extending dimple-like protrusions that define the height of the second fluid volume on the second side of the separator plate. As a result, the intermediate planar region is positioned between the protrusions, The intermediate planar region is shaped to selectively vary its height in at least one direction across the electrochemically active cell region such that the relative heights of the first fluid volume and the second fluid volume increase and decrease in corresponding terms. Electrochemical cell unit.

2. The electrochemical cell unit according to claim 1, wherein the height of the intermediate planar region changes as a discontinuous transition.

3. The electrochemical cell unit according to claim 1, wherein the height of the intermediate planar region changes as a continuous transition.

4. The electrochemical cell unit according to any one of claims 1 to 3, wherein the electrochemical cell unit includes an inlet to and an outlet therefrom for a first fluid volume, which is positioned toward opposing edges of the cell unit, with the electrochemically active cell regions positioned between them, and at least one direction of height variation in the intermediate planar region is such that the height of the first fluid volume is smaller in the central area of ​​the cell unit than in the area adjacent to the edges of the cell unit.

5. The electrochemical cell unit according to any one of claims 1 to 3, wherein at least one direction of height change in the intermediate planar region is substantially perpendicular to a straight line between an inlet to the first fluid volume and an outlet from the first fluid volume, and the height of the first fluid volume is smaller along the straight line than with respect to at least one side of the straight line.

6. The electrochemical cell unit according to any one of claims 1 to 3, wherein the electrochemical cell unit includes an inlet to and an outlet therefrom for a first fluid volume, which is positioned toward opposing edges of the cell unit between which the electrochemically active cell regions are located, and at least one direction of height change in the intermediate planar region is such that the height of the first fluid volume decreases toward the outlet of the first fluid volume.

7. The electrochemical cell unit according to claim 6, wherein the electrochemical cell unit includes an inlet and an outlet therefrom to a second fluid volume, which is located toward or outward to opposing edges of the cell unit, between which the electrochemically active cell region is positioned, and the inlet and outlet of the second fluid volume are arranged such that the height of the second fluid volume increases from the inlet to the outlet of the second fluid volume.

8. The electrochemical cell unit according to claim 7, wherein the second fluid volume includes a bypass for the second fluid around a portion of the 3D region adjacent to the inlet to the second fluid volume.

9. The electrochemical cell unit according to any one of claims 1 to 3, wherein the three-dimensional (3D) region covers the entirety of the electrochemically active cell region.

10. The electrochemical cell unit according to any one of claims 1 to 3, wherein the dimple-shaped protrusions of the first plurality of dimple-shaped protrusions and the second plurality of dimple-shaped protrusions are shaped such that their outermost portions do not include any contact portions extending in any lateral direction that extends in the height direction, such that they form channels within a fluid volume in which the flow is constrained.

11. The electrochemical cell unit according to any one of claims 1 to 3, wherein the first side of the separator plate faces the cell layer, and each contact portion of the first plurality of dimple-shaped protrusions contacts the cell layer.

12. The electrochemical cell unit according to claim 11, wherein each contact portion of the first plurality of dimples and each contact portion of the second plurality of dimples each form a first plane and a second plane, and the first plane and the second plane are each planes and parallel to each other.

13. The electrochemical cell unit according to any one of claims 1 to 3, wherein the architecture of the cell unit is selected from one of metal-supported, anode-supported, electrolyte-supported, and cathode-supported architectures.

14. The electrochemical cell unit according to any one of claims 1 to 3, wherein the cell unit is a metal-supported cell unit in which the cell layer comprises a metal support plate on its first side that supports the electrochemically active cell region provided on a porous region.

15. At least one of the separator plate and the metal support plate has a flanged peripheral feature formed by pressing the plate into a concave configuration, The separator plate and the metal support plate are directly joined at the flanged peripheral feature, forming the first fluid volume between them. The electrochemical cell unit according to claim 14.

16. The electrochemical cell unit according to claim 14, further comprising a spacer plate disposed between the metal support plate and the separator plate, wherein the spacer plate has an opening therein that defines the first fluid volume, and the metal support plate, the spacer plate, and the separator plate are joined around each other.

17. The electrochemical cell unit according to any one of claims 1 to 3, wherein the first fluid volume is for fuel and the second fluid volume is for oxidizing agent.

18. The electrochemical cell unit according to any one of claims 1 to 3, wherein the height of the first fluid volume is lower than the height of the second fluid volume.

19. An electrochemical cell stack comprising a plurality of electrochemical cell units according to any one of claims 1 to 3, The first side of the separator plate of the first electrochemical cell unit faces the cell layer of the first electrochemical cell unit, and the first fluid volume is sealed between them. The second side of the separator plate of the first electrochemical cell unit faces the cell layer of the second adjacent electrochemical cell unit in the stack of the cell unit, and the second fluid volume is sealed between them. Electrochemical cell stack.

20. The electrochemical cell stack according to claim 19, wherein the electrochemical cell unit includes an inlet to and an outlet therefrom for a first fluid volume positioned toward opposing edges of the cell unit, between which the electrochemically active cell regions are located, and at least one direction of height variation in the intermediate plane region is such that the height of the first fluid volume is smaller in the central area of ​​the cell unit than in the area adjacent to the edges of the cell unit, and the electrochemical cell stack further includes means for supplying and discharging a first fluid from the first fluid volume positioned toward opposing edges of the cell unit, between which the electrochemically active cell regions are located, and at least one direction of height variation in the intermediate plane region is such that the height of the first fluid volume is smaller in the central area of ​​the cell unit than in the area adjacent to the edges of the cell unit.

21. The electrochemical cell stack according to claim 19, wherein at least one direction of height variation in the intermediate plane region is substantially perpendicular to a straight line between an inlet to the first fluid volume and an outlet from the first fluid volume, the height of the first fluid volume is smaller along the straight line than with respect to at least one side of the straight line, the electrochemical cell stack further comprises means for supplying and discharging the first fluid from the first fluid volume, the electrochemical active cell region is positioned between the supply means and the discharge means, at least one direction of height variation in the intermediate plane is perpendicular to a straight line between the supply means and the discharge means, and the height of the first fluid volume is smaller along the straight line than with respect to at least one side of the straight line.

22. The electrochemical cell stack according to claim 19, wherein the electrochemical cell unit includes an inlet to and an outlet therefrom to the first fluid volume, which is positioned toward opposing edges of the cell unit, between which the electrochemically active cell region is positioned, such that at least one direction of height change in the intermediate planar region causes the height of the first fluid volume to decrease from the inlet to the outlet of the first fluid volume, and the electrochemical cell stack further comprises means for supplying and discharging the first fluid from the first fluid volume, the electrochemically active cell region is positioned between the supplying means and the discharging means, such that at least one direction of height change in the intermediate planar region causes the height of the first fluid volume to decrease from the supplying means to the first fluid volume to the discharging means of the first fluid volume.

23. The electrochemical cell stack according to claim 22, further comprising means for supplying and discharging a second fluid from the second fluid volume, wherein the electrochemically active cell region is positioned between the means for supplying and discharging the second fluid from the second fluid volume, and at least one direction of height change in the intermediate planar region is such that the height of the second fluid volume increases from the means for supplying the first fluid volume to the means for discharging the first fluid volume.

24. The electrochemical cell stack according to claim 23, wherein the electrochemical cell stack comprises a baffle configured to provide a bypass for the second fluid around a portion of the 3D region that is located within a housing and is close to means for supplying the second fluid to the second fluid volume.

25. The electrochemical cell stack according to claim 20, wherein the means for supplying and discharging the first fluid from the first fluid volume comprises at least one fluid port provided through the separator plate and the cell layer, the at least one fluid port being in fluid communication with the first fluid volume, and the at least one fluid port of each cell unit being aligned to form at least one passage extending in the stack direction, which is a passage collected and distributed internally by a manifold.

26. A method for manufacturing a separator plate for an electrochemical cell unit, wherein the electrochemical cell unit comprises a cell layer having an electrochemically active cell region, and the method is To provide a flat metal sheet, The metal sheet is deformed to provide a three-dimensional (3D) region within the electrochemical cell unit that, when in use, covers at least a portion of the electrochemically active cell region of the cell layer, wherein the three-dimensional (3D) region is A first set of outwardly extending dimple-like protrusions defines the height of the first fluid volume on the first side of the separator plate, A plurality of outwardly extending second dimple-shaped protrusions define the height of the second fluid volume on the second side of the separator plate, Includes, As a result, the intermediate planar region is positioned between the protrusions, The intermediate planar region is shaped to selectively vary its height in at least one direction across the electrochemically active cell region such that the relative heights of the first fluid volume and the second fluid volume increase and decrease in corresponding terms. That thing, Methods that include...

27. The method according to claim 26, wherein any one or more of the 3D features of the molded port features, flanged peripheral features, and other molded flow control features are also formed on the separator plate in the same step as the intermediate planar region and protrusions are formed.

28. The use of the electrochemical cell unit according to any one of claims 1 to 3, wherein the shape of the intermediate planar region is selectively adjusted to optimize the distribution of the first fluid within the first fluid volume, taking into account the number and location of each inlet and outlet through which the first fluid enters and exits the cell unit during operation.

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