Metal-supported cell unit

Abstract

The fuel cell system includes at least a pair of cells (110a, 110b), each cell including a metal substrate (120a, 120b) having first and second sides and a porous region (124) providing fluid communication between the sides, and a planar cell chemistry layer (111, 112, 113) including a fuel electrode layer, an electrolyte layer, and an air electrode layer, and coated or deposited over and supported by the porous region (124) on a first side thereof, the metal substrate (120a, 120b) including a metal electrode layer, an electrolyte layer, and an air electrode layer. A metal-supported planar cell device (200) in which the metal substrates (120) are arranged in a stacked configuration with the cell chemistry layers (111, 112, 113) of the metal substrates (120) overlying one another such that both of their first sides or both of their second sides face inward in a spaced apart opposing relationship, whereby the inwardly facing sides define a common first fluid volume (140) for one of fuel or oxidant between the metal substrates (120).

Description

[Technical Field]

[0001] The present invention relates to an improved cell unit and a cell stack including a plurality of such cell units, and to a method for manufacturing the same. More particularly, the present invention relates to a metal-supported cell unit and a stack thereof, and more particularly, to a metal-supported solid oxide fuel cell (MS-SOFC) unit and a stack thereof, and a metal-supported solid oxide electrolysis cell (MS-SOEC) unit and a stack thereof. [Background technology]

[0002] solid oxide fuel cell Fuel cell units use an electrochemical conversion process to oxidize fuel to generate electricity. Fuel cell units may be tubular or planar in form. Solid oxide fuel cells (SOFCs) are based on a solid oxide electrolyte that conducts negative oxygen ions from cathodes to anodes located on either side of the electrolyte. To this end, a fuel or reformed fuel is in contact with the anode (fuel electrode), and an oxidant, such as air or an oxygen-rich fluid, is in contact with the cathode (air electrode).

[0003] When designing a SOFC stack, significant mechanical, electrical, and thermal design challenges are encountered. For example, in a planar SOFC stack configuration, stacks of cells are typically arranged in a stacking direction from one end of the stack (e.g., from the base plate end) to the other end (e.g., the end plate end). The operational performance of the fuel cell / fuel cell stack repeating layers is affected by temperature and other factors.

[0004] Metal-supported solid oxide fuel cells Conventional ceramic-supported (e.g., anode-supported) SOFCs have low mechanical strength and are vulnerable to fracture. Metal-supported SOFCs (MS-SOFCs), in which the active fuel cell component layers are supported on a metal substrate, have recently been developed. In these cells, the ceramic layers perform only electrochemical functions (i.e., they are not self-supporting), and therefore can be very thin. Such metal-supported SOFC stacks are more robust, less costly, and have superior thermal properties. Metal-supported SOFC stacks can also be fabricated using conventional metal welding techniques.

[0005] WO 2015 / 136295 describes a metal-supported SOFC in which the electrochemically active layers (or active fuel cell component layers) comprise an anode layer, an electrolyte layer, and a cathode layer, each deposited on and supported by a metal support plate 120 (e.g., a foil). As shown in FIGS. 1a-1c, a fuel cell repeat unit 90 comprises three plates or planar components—a metal support plate 120, a separator plate (or interconnect) 150, and a spacer plate 130 sandwiched between the plates. The fuel cell repeat unit also has fluid ports 188, 200 for oxidant or fuel. The three plates are stacked together and welded (fused together) via the spacer plate 130 to form a single metal-supported solid oxide fuel cell unit 90, with a central fluid volume 140 defined by a space provided in the spacer plate 130. The metal components of the fuel cell stack repeating layer 90 are in electrical contact with each other, and the flow of electrons between them is primarily via the fuse / weld path, avoiding surface-to-surface contact resistance losses.

[0006] In MS-SOFCs, the metal substrate may be an inherently porous metal substrate formed from a powder metal precursor (e.g., by tape casting), or, more preferably, formed from a metal support plate with porous regions in the form of through-holes or small openings surrounded by non-porous (solid) regions. A porous region 124 extends through the metal support plate 120, and the anode layer 113 (or cathode 111, depending on the polarity orientation of the electrochemically active layer 110) is coated over that region, followed by successive layers, which are then supported by the metal support plate 120. As shown, the electrolyte layer is typically coated over the side edges of the innermost electrode and extends over the metal substrate to seal the gas within the porous region and the innermost electrode. The porous region allows a fluid volume 140 (defined by adjacent plates 120, 150 and spacer plate 130) to fluidly communicate with the electrochemically active layer 110 on the support plate 120 through the small openings. As shown, the electrolyte layer is typically coated over the side edges of the innermost electrode and extends over the metal substrate (as extension layer 123) to seal the gas within the porous region and the innermost electrode.

[0007] The separator plate 150 has top and bottom corrugations extending upward to the cathode 111 (or anode 113, depending on the polarity orientation of the electrochemically active layer 110) of the subsequent fuel cell unit 90 stacked on top of it, and downward to the metal support plate 120 of its own fuel cell unit. This provides electrical connection between adjacent fuel cell units 90 in the stack and positions the electrochemically active layers 110 of the stack (typically one on each fuel cell unit) in series with each other. Other stamped three-dimensional features, such as rounded or elongated depressions (or valleys and peaks) extending from both sides, are also suitable for electrical contact and structural support (resisting stack compression forces).

[0008] Other teachings relating to fuel cells, fuel cell stacks, fuel cell stack assemblies, and heat exchanger systems, apparatus, and methods can be found in WO 2002 / 35628, WO 2003 / 07582, WO 2004 / 089848, WO 2005 / 078843, WO 2006 / 079800, WO 2006 / 106334, WO 2007 / 085863, WO 2007 / 110587, and the like. , WO 2008 / 001119, WO 2008 / 003976, WO 2008 / 015461, WO 2008 / 053213, WO 2008 / 104760, WO 2008 / 132493, WO 2009 / 090419, WO 2010 / 020797, WO 2010 / 061190 and WO 2015 / 004419.

[0009] A solid oxide electrolysis cell (SOEC) may have the same structure as a SOFC, but is essentially a solid oxide fuel cell operated in a regenerative mode to achieve electrolysis of water and / or carbon dioxide to produce hydrogen gas and / or carbon monoxide and oxygen by using a solid oxide electrolyte. In a SOFC, fuel (e.g., hydrogen gas) is supplied by a fuel port and used by the cell, whereas in a SOEC, the cell produces hydrogen gas, which is collected, for example, at the fuel port.

[0010] The present invention relates to a stacked solid oxide cell unit having a structure suitable for use as an SOEC or SOFC. For convenience, hereinafter either an SOEC or SOFC cell unit will be referred to as a "cell unit" (i.e., meaning an SOEC or SOFC cell unit).

[0011] There is a continuing drive to make fuel cells more cost-effective - reducing the manufacturing cost of fuel cells can be of great benefit to reduce the cost of entry into fuel cell energy production. Summary of the Invention

[0012] According to one aspect, a metal-supported planar cell device is described, the metal-supported planar cell device comprising at least a pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between the sides, and a planar cell chemistry layer comprising a fuel electrode layer, an electrolyte layer, and an air electrode layer, and coated or deposited over and supported by the porous region on the first side, wherein the metal substrates are in a stacked arrangement with the cell chemistry layers of the metal substrates overlying each other such that both of the first sides of the metal substrates or both of the second sides of the metal substrates face inwardly in a spaced apart opposing relationship, such that the inwardly facing sides define a common first fluid volume between the metal substrates for one of fuel or oxidant.

[0013] The present invention relates to metal-supported planar cell devices, i.e., cell devices in which the cell chemistry layers are planar (extending only in a single plane) and non-freestanding, i.e., they exist only as thin coatings or films respectively deposited over and integrally supported by a porous metal substrate. This is in contrast to anode-supported, cathode-supported, or electrolyte-supported cells in which the cell chemistry layers exist alone to form rigid, free-standing tiles that can be mounted or attached to other support structures. The present invention particularly relates to metal-supported solid oxide fuel cells "MS-SOFC" or solid oxide electrolysis cells "MS-SOEC."

[0014] The porous metal substrates support cell chemistry layers only on a first side of the porous metal substrate; the second side of each substrate does not support any cell chemistry layers; rather, the second sides face each other and are exposed to a common volume or space between the second sides that allows the first fluid to be supplied to the innermost electrode (closest to the supporting metal substrate) on each of the first sides.

[0015] The (active) cell chemistry layers are planar, and therefore at least a portion of the metal substrate supporting that chemistry is also planar. The cell chemistry layers are stacked in the same order across each region so that the metal substrate defines a common first fluid volume in which each cell can serve as a fuel volume with the fuel electrode closest to the supporting metal substrate, or an oxidizer volume with each cell having the air electrode closest to the supporting metal substrate. In the stacked arrangement, the cell chemistry layers are one above the other (e.g., in parallel planes) and are typically laterally aligned with one another (i.e., aligned with one another).

[0016] The two fuel electrodes may be electrically connected, and the two air electrodes of a pair of cells may also be electrically connected. Typically, the innermost electrode (closest to the supporting metal substrate) is electrically connected by an electrical connection between two respective opposing metal substrates. The two outermost electrodes are connected by a connection between two respective current collectors on the outermost electrodes.

[0017] The metal substrates may be sealingly connected to one another around their periphery.

[0018] Preferably, the pair of metal substrates comprises two separate metal plates, typically identical, that are directly or indirectly connected to one another to form a stacked arrangement, such that each metal plate itself has an integral porous region (bounded by a non-porous region) and supports a cell chemistry layer coated thereon.

[0019] In one embodiment, two metal plates are indirectly connected to each other to form a stacked arrangement, optionally with a (flat) metal spacer plate disposed between the two metal plates. The two metal plates and the intermediate metal spacer plate may be sealingly connected to each other at least around their periphery, for example by welding through all three components.

[0020] If the spacer is placed between two separate metal plates, this has the disadvantage that additional components are required in the stack, but the advantage that a flat, planar metal plate can be used onto which the cell chemistry layer can be conveniently laid directly by conventional coating or spray deposition techniques. The spacer may comprise a frame or flat perimeter component (located beyond the active cell chemistry area) sandwiched between the flat metal substrates to provide a volume for the first fluid volume and sealingly enclose the first fluid volume.

[0021] Typically, there should be no large structures within the fluid volume that obstruct the flow, but if cell chemistries are provided that may support and / or contact the substrate (or chemical structure), further spacer components in the form of open or highly permeable structures may be provided.

[0022] Alternatively (as opposed to indirectly connecting substrates), two metal plates may be directly connected to one another so that they abut one another to form a stacked arrangement, with one or both of the metal plates having an inherent molded feature (e.g., a flanged perimeter feature) that forms a first fluid volume between the plates. The two metal plates may be directly and sealingly connected to one another around at least their perimeters, for example, by welding. This eliminates the need for spacers, thereby reducing the number of components and thus material waste. The two metal plates may also be conveniently electrically connected.

[0023] Alternatively (to separate the substrates), the metal substrate can be formed as a single continuous metal substrate having a first side on which a pair of cell chemistry layers are coated or deposited, respectively, over the porous region, and the continuous metal substrate can be folded (e.g., through 180 degrees) between the cell chemistry layers so that the cell chemistry layers overlie each other to form a folded pair of cells that define a first fluid volume for one of the fuel or oxidant. Advantageously, the innermost electrode (i.e., closest to the supporting metal substrate) is electrically connected by the continuous metal substrate. In such a configuration, fewer components and welding / sealing are essentially required.

[0024] The continuous metal substrate can be bent through 180 degrees, which can take the form of two 90-degree folds separated by a short section of the continuous metal substrate, which serves to define a common fluid volume enclosed by the continuous metal substrate. As described elsewhere, molded forms or spacers are provided to support the substrate and maintain an open common fluid volume.

[0025] The device preferably further comprises a plurality of folded pairs of cells stacked next to each other in a bank of cells. In the bank, the innermost electrodes (closest to the supporting metal substrate) may be electrically connected by a continuous metal substrate, and the outermost electrodes may be electrically connected by a current collecting structure. The current collecting structure may be a permeable supporting structure, which need only be exposed to one fluid environment, the same fluid environment across the entire surface area of ​​the current collecting structure. This reduces the thermal and chemical requirements of the current collecting structure.

[0026] In the bank, each folded pair of cells is preferably formed from a separate respective metal substrate, which is folded once so that it has only one folded end, and the first fluid volume is located inside the folded substrate.

[0027] Alternatively (to separate substrates), adjacent folded pairs of cells in a bank may be formed from a common continuous metal substrate that is folded multiple times so that it has multiple opposing folded edges. Such substrate may define multiple respective first fluid volumes for one of fuel or oxidant. Such volumes may alternate with respective second fluid volumes for the other of fuel or oxidant.

[0028] At least one of the metal substrates preferably includes a flanged perimeter feature around which the metal substrates are sealed to each other to form a common first fluid volume between them. The flanged perimeter feature may be formed by pressing the substrates into a concave feature. Both metal substrates of a cell pair may include a flanged perimeter feature.

[0029] At least one fluid port, typically at least one inlet port and at least one outlet port, is preferably provided as an opening through each of the metal substrates, and the respective fluid ports are aligned with each other in the stacking direction and in communication with a common first fluid volume. Alternatively, the at least one fluid port is in communication with a common second fluid volume. Alternatively, the at least one fluid port is in communication with the common first fluid volume and the at least one second fluid port is in communication with the common second fluid volume. The at least first fluid port and the at least second fluid port can deliver a first fluid to the first fluid volume and a second fluid to the second fluid volume, respectively. At least a first exhaust port may be in communication with the common first fluid volume and at least a second exhaust port may be in communication with the common second fluid volume. At least a first exhaust port and at least a second exhaust port are capable of extracting a first exhaust fluid from the first fluid volume and a second exhaust fluid from the second fluid volume.

[0030] At least one of the metal substrates is preferably provided with a molded port feature formed about the port and extending inwardly within the common first fluid volume, elements of the molded port feature being laterally spaced from one another to define fluid paths between the elements from the ports to allow passage of fluid from the ports to the common first fluid volume, and the molded port feature is preferably formed by stamping.

[0031] At least one of the metal substrates may be provided with a molded port feature formed around the port and extending outwardly away from the common first fluid volume. When multiple such cell pairs are stacked next to each other, such features may serve laterally to locate sealing gaskets provided between the cell pairs, or such features may interface with adjacent plates to form hard stops to limit compression of gaskets provided between the cell pairs, or may form surfaces upon which a seal can be formed in situ from a sealing paste or the like. Within a bank of cells, the metal substrates may be electrically connected to each other, so that such molded port features may be welded to features of adjacent cells to conveniently provide electrical connections as well as port / manifold sealing.

[0032] If the compressive forces for current collection are low or the cells are sufficiently rigid, a support structure may be provided within the common first fluid volume to help maintain the spacing between the opposing inward-facing sides.

[0033] The support structure may be a permeable support structure that only needs to be exposed to one fluid environment, which is the same across the surface area of ​​the support structure. This reduces the thermal and chemical requirements of the support structure. The innermost electrode (closest to the supporting metal substrate) may be electrically connected by the metal substrate, and the outermost electrode may be electrically connected by the current collecting structure. The current collecting structure may be a permeable support structure that only needs to be exposed to one fluid environment, which is the same across the surface area of ​​the current collecting structure. This reduces the thermal and chemical requirements of the current collecting structure.

[0034] A catalyst may be provided on the support structure within the common first fluid volume to promote internal reforming, for example, if the common first fluid volume is a fuel volume. If the support structure is not provided within the common first fluid volume, for example, if the common first fluid volume is a fuel volume, such a catalyst may be provided on a metal substrate surface.

[0035] Preferably, the inwardly facing side defines a first fluid volume of fuel. The inwardly facing side is typically the second side of the metal substrate. In that arrangement, the cell chemistry faces outward and current can be conveniently collected from the outermost electrode.

[0036] Typically, the fuel electrode layer is the first of the cell chemistry layers deposited on the first side of the metal substrate. If the inward-facing side defines a first fluid volume for fuel (when operating as a SOFC), then the inward-facing side becomes the second side of the metal substrate, and fuel gas passes from the second side to the first side through the porous region and into contact with the fuel electrode layer.

[0037] In another cell arrangement, the inward-facing side defines a first fluid volume for the oxidant. In this case, again if the fuel electrode layer is the first of the cell chemistry layers deposited on the first side of the metal substrate, the inward-facing side becomes the first side so that the cell chemistry layers are in a common first fluid volume, and the air electrode layer is exposed to the first fluid volume for the oxidant. In that arrangement, the outermost electrode is located within the substrate, and any current collecting devices (at opposite potential) must be carefully insulated from the substrate itself.

[0038] Preferably, multiple pairs of cells are stacked adjacent to each other to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, and the first fluid volume is for either fuel or oxidant, and at least one second fuel volume is for the other of fuel or oxidant. This means that the first and second fluid volumes are defined alternately along the stacking direction. Thus, each other side of the outward-facing metal substrate in each pair of cells of the bank is in a spaced-apart, opposing relationship with its counterpart in each adjacent pair of cells. Typically, the first fluid volume is defined between the metal substrates in a pair of cells, and the second fluid volume is defined between the adjacent pairs.

[0039] In a bank, adjacent first fluid volumes may be in fluid communication with each other through openings provided through their respective metal substrates, which are aligned in the stacking direction to form internal passages (manifolds) within the bank. The same may be true for the second fluid volumes. However, one of the two fluid volumes may have externally manifolded inlet and / or outlet ports. The internal passages may be sealed by gaskets provided between pairs of cells within the bank.

[0040] The support structure may be present within the common first fluid volume and may comprise a catalyst, for example, to promote internal reforming. If the support structure is not provided within the common first fluid volume, such a catalyst may be provided on a metal substrate, for example, when the common second fluid volume is a fuel volume.

[0041] It is preferred that all fuel electrodes in a bank be electrically connected and / or all air electrodes in a bank be electrically connected, meaning that electrodes of one type are connected in parallel, which relatively increases the current output of the bank.

[0042] In a highly preferred arrangement, all respective pairs of cells in a bank are welded together, thus electrically connecting all of the substrates. Welding can be done during layup as each cell is added to the stack.

[0043] Preferably, the metal substrate and cell chemistry layers are positioned with side edges and the connected fuel and / or air electrodes are connected along the same side edges.

[0044] The fuel electrodes in one bank are preferably connected in series with the air electrodes of the next adjacent bank, thereby relatively increasing the voltage output of the bank of fuel cells.

[0045] An insulating sheet is preferably placed between adjacent banks to prevent direct electrical contact between the adjacent banks (e.g., the outermost electrodes of adjacent banks). For example, with the banks connected in series, there may be an electrical connection between the last substrate of one bank and the outermost electrode of the adjacent bank.

[0046] In one embodiment, a single cell is provided at the end of a bank, and the cell makes direct electrical contact with an adjacent bank (e.g., between the substrate of the single cell and the outermost electrode of the adjacent bank), connecting the adjacent banks in series.

[0047] Such single or unpaired cells may comprise a metal substrate with an active cell chemistry layer thereon, which is attached to a non-porous metal sheet to form an end coupon (e.g., by welding to form an end coupon with an enclosed fluid volume). The metal sheet may, for example, be a flat, unshaped, non-perforated metal substrate. In this manner, adjacent banks may advantageously be connected in series in face-to-face contact across most of the cell area without the need for further electrical connections. For example, the interconnects in one bank may all be connected in parallel, and the outermost interconnects may contact (physically and electrically) the non-porous metal sheet of the end coupon of the adjacent bank to form a series connection. In that adjacent bank, the non-porous metal sheet and substrates are at the same potential and are connected in parallel with all other metal substrates in that bank. Thus, the parallel-connected substrates in the adjacent bank are connected to the parallel-connected interconnects in the first bank by a series connection.

[0048] According to a further aspect, a method of assembling a metal-supported planar cell device is described, the method including the steps of providing first and second cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between the sides, a fuel electrode layer, an electrolyte layer, and an air electrode layer, and a planar cell chemistry layer coated or deposited over and supported by the porous region on the first side; and inverting one of the cells relative to the other, so that the metal substrates are in a stacked arrangement with the cell chemistry layers of the metal substrates overlying each other, such that both of the first sides of the metal substrates or both of the second sides of the metal substrates face inward in a spaced apart opposing relationship, defining a common first fluid volume for one of fuel or oxidant between the metal substrates and forming the cell device.

[0049] The method may include electrically connecting either the two fuel electrodes or the two air electrodes of a pair of unit cells, with the continuous substrate allowing such connections to be made.

[0050] Thus, a repeating unit can be manufactured that includes a pair of cells that define a common first fluid volume between the pair of cells.

[0051] Preferably, the metal substrate is formed as a single continuous metal substrate, and the inverting step includes folding the continuous metal substrate between the cell chemistry layers so that the cell chemistry layers overlie each other to form a folded pair of cells defining a first fluid volume for one of fuel or oxidant. The fold may span 180 degrees or may comprise two 90-degree folds separated by a distance corresponding to the desired height of the first fluid volume.

[0052] Preferably, the cell chemistry layers of the twin cells are each coated or deposited over the porous region of the first side, followed by folding of the metal substrate. Advantageously, the coating or deposition followed by folding means that the substrate does not need to be flipped over to coat or deposit the cell chemistry layers of the twin cells, and also means that the cell chemistry layers of the twin cells can be coated or deposited during the same manufacturing process.

[0053] Pre-folds are preferably formed on the metal substrate prior to coating or depositing the cell chemistry layers. The pre-folds are precursors to the folds and are placed at the desired locations of one or more folds, followed by coating or depositing the cell chemistry layers of the paired cells on either side of the pre-fold. The pre-folds may be formed by stamping or scoring a continuous or discontinuous line across the metal substrate. If the fold comprises two 90-degree folds, two pre-fold lines are formed. Additional pre-fold lines can be formed as precursors to a multiply folded substrate. The pre-folds form lines of weakness along which the substrate is more likely to bend during the folding step after coating or depositing the cell chemistry layers, thereby reducing the likelihood of damaging the cell chemistry layers in the process of folding the substrate. In other words, the pre-folds form lines of weakness.

[0054] The step of forming the pre-fold may be followed by a planarization step, which ensures that the substrate is sufficiently flat for the coating or deposition of cell chemistry layers.

[0055] Preferably, the method further comprises cutting an opening through each of the metal substrates to form at least one inlet port and at least one outlet port.

[0056] Thus, a port for fluid delivery is formed in each metal substrate. Upon folding and / or stacking of the metal substrates, the respective fluid ports are aligned with one another in the folding and / or stacking direction and communicate with a common first fluid volume. Additional ports may similarly communicate with a second fluid volume.

[0057] Preferably, at least one of the metal substrates is pressed around the port to form a molded port feature that extends inwardly into the common first fluid volume or outwardly away from the common first fluid volume.

[0058] In a next step, the metal substrates may be sealed to one another around some or all of the perimeter of the metal substrates (e.g., around one, two, three, or all four sides) by a flanged perimeter or a separate spacer component. In the case of a folded continuous substrate, the folded sides may or may not require a flanged perimeter. A next step of welding or brazing around the flanges may be used. This step of welding or brazing around the perimeter seals the first fluid volume from the rest of the environment, which may or may not be in communication with the second fluid volume.

[0059] The pressing step or steps provide a concave surface in the first and / or second fluid volumes. The peripheral flange and the inwardly extending molded port feature within the common first fluid volume may be formed in the same or separate pressing steps. The pressing and cutting steps may occur before or after the step of coating or depositing the cell chemistry layer. Preferably, the pressing and cutting steps may occur before the step of coating or depositing the cell chemistry layer to prevent damage to the cell chemistry layer.

[0060] Preferably, additional cell devices are provided in the same manner as the first cell device, and these cell devices are stacked into banks to provide electrical connections between the fuel electrodes within the banks and / or between the air electrodes within the banks. A further step may include stacking respective banks of cells to form a stack of cells. Insulators may be provided between adjacent banks so that end cells in adjacent banks are not connected in series. Alternatively, adjacent banks may be connected in series if a single cell is provided at the end of the bank.

[0061] The metal substrates are generally rectangular and are provided with port holes at their left and right ends with the cell chemical layers in a central region facing outward from each pair of metal substrates, and an electrically and fluidically conductive spacer overlies the uppermost chemical layer (outermost electrode) in contact with the chemical layers and spaced from the metal substrates to provide electrical contact to the chemical layers of another cell disposed above in the stacked arrangement, and the spacer is provided with electrical connections at its leading and / or trailing edges perpendicular to the location of the port holes. The electrically conductive spacer is preferably separated from the underlying metal substrate by an extended region of electrolyte that surrounds the central region and acts as an insulator. [Brief explanation of the drawings]

[0062] [Figure 1a] 1 shows an exploded view of a prior art solid oxide fuel cell unit. [Figure 1b] A cross-sectional view of a prior art fuel cell unit is shown inverted relative to FIG. 1a. [Figure 1c] 1 shows a cross-sectional view of two prior art fuel cell units in a stacked arrangement. [Figure 2] 1 shows a novel arrangement of a pair of cell units in a back-to-back configuration with the active cell chemistry layers facing outward. [Figure 3] 1 shows another novel arrangement of a pair of cell units in a face-to-face arrangement with the active cell chemistry layers facing inward. [Figure 4a] 3 shows a bank of fuel cell units comprising two pairs of cell units, each pair in a back-to-back arrangement according to FIG. 2. [Figure 4b] 10 shows another bank of cell units with another spacing arrangement. [Figure 5] A novel stacking arrangement is shown in which pairs of banks, each bank according to FIG. 4a, are stacked on top of each other with an insulating layer between adjacent banks. [Figure 6] 6 shows the stacked arrangement of FIG. 5 including series electrical connections between the banks. [Figure 7a]1 shows another stacking arrangement in which each bank has three pairs of cell units, two banks stacked on top of each other with an insulating layer between adjacent banks, and the banks are electrically connected in series. [Figure 7b] 10 illustrates an alternative arrangement for electrical connections between banks. [Figure 7c] 10 illustrates yet another arrangement for electrical connections between banks. [Figure 8a] 1 shows a novel cell unit comprising a metal substrate and active cell chemistry layers. [Figure 8b] Two such cell units are shown in a back-to-back arrangement with the active cell chemistry layers facing outward. [Figure 8c] 8b shows a bank of cell units comprising two pairs of cell units, each pair in a back-to-back arrangement according to FIG. 8b. [Figure 9a] 1 shows a novel cell unit with port features formed therein. [Figure 9b] Two such cell units are shown arranged in a back-to-back configuration with the active cell chemistry layers facing outward. [Figure 9c] 9b shows a bank of cell units comprising two pairs of cell units, each pair in a back-to-back arrangement according to FIG. 9b. [Figure 10a] 1 shows a further novel cell unit with formed port features. [Figure 10b] Two such cell units are shown arranged in a back-to-back configuration with the active cell chemistry layers facing outward. [Figure 10c] 10b shows a bank of fuel cell units comprising two pairs of cell units, each pair in a back-to-back arrangement according to FIG. 10b. [Figure 10d] 10c shows a cell arrangement comprising two banks of cell units, each bank comprising two pairs of cell units according to FIG. 10c. [Figure 10e] 1 shows a cell device with two banks of cell units, one of the banks having a single cell unit at the end of the bank. [Figure 11]1 shows a first side of a cell unit in a top perspective view. [Figure 12a] FIG. 11a shows a pair of cell units with their respective metal support substrates welded together around their flanged peripheries. [Figure 12b] 12b shows a cross-section of the cell unit according to FIG. 12a from the flanged periphery of the substrate through the chimney. [Figure 13] 13 shows a pair of cell units according to FIG. 12, with an air-side conductive support structure positioned above the cell units. [Figure 14a] FIG. 14 shows a pair of cell units and a conductive support structure according to FIG. 13, with a third cell unit added on top of the support structure. [Figure 14b] 14b is a cross-sectional view of the cell unit according to FIG. 14a from the flanged periphery of the substrate through the chimney. [Figure 15a] 1 shows a stack of cell units and conductive support structures. [Figure 15b] 15b is a cross-sectional view of the bank of cell units according to FIG. 15a from the flanged periphery of the substrate through the chimney. [Figure 15c] 15a shows a stacking arrangement in which pairs of banks, each according to FIG. 15a, are stacked one on top of the other with an insulating layer between adjacent banks. [Figure 16a] Another novel arrangement is shown of a pair of cells in a back-to-back configuration, with the outwardly facing active cell chemistry layers supported by a single folded substrate. [Figure 16b] 16a shows a bank of cell units comprising two pairs of cell units, each pair in a back-to-back arrangement according to FIG. 16a. [Figure 16c] 16b shows a schematic representation of a cell unit according to FIG. 16a with port features formed therein; [Figure 17a] Another novel cell unit is shown comprising an arrangement of two pairs of fuel cells, each pair in a back-to-back arrangement with the active cell chemistry layers facing outward, with the two pairs of cells supported by a single folded substrate. [Figure 17b]17b shows a schematic representation of a cell unit according to FIG. 17a with port features formed therein; DETAILED DESCRIPTION OF THE INVENTION

[0063] A list of reference numbers used in this specification is provided at the end of the specific embodiments. Repeat use of reference numbers in the present specification and drawings is intended to represent the same or similar features or elements.

[0064] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope thereof. For example, features described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0065] In the following description, air is used as the oxidant, and therefore references elsewhere to "oxidant" can be construed as references to "air" and vice versa.

[0066] Referring to FIG. 2, a device 200 is shown that includes a pair of cell units arranged back-to-back. The pair of cell units 200 includes a first cell unit 110a supported by a first metal support plate 120a and a second cell unit 110b supported by a second metal support plate 120b. Each metal-supported cell unit 110a, 110b includes cell chemistry layers 111, 112, 113 deposited or coated on a metal substrate 120 to form an electrochemically active layer 110. The anode layer 113, electrolyte layer 112, and cathode layer 111 are disposed successively over the porous region 124. However, in some cell devices, the order may be reversed (with the cathode layer closest to the substrate).

[0067] 1, the metal substrate 120 is a metal foil, typically a ferritic stainless steel. The porous region 124 comprises an array of through-holes formed by drilling (or other means, e.g., etching) that extend from a first side 125 to an opposite (second side 126) of the metal substrate 120, and the porous region is surrounded by a non-porous (solid) region.

[0068] The anode layer 113, electrolyte layer 112, and cathode layer 111 may be formed on a planar metal substrate 120 by deposition, such as chemical vapor deposition, electrostatic deposition, spray deposition, spin-on deposition, or powder deposition. This process may be a two-step process involving the deposition of powder or granular material followed by sintering or other processing to form each layer of the solid oxide cell. Because each layer is thin, none of the layers are self-supporting; that is, a metal substrate is required to support the solid oxide chemical layers. Other barrier layers, such as an extended electrolyte layer 123, may also be provided. As with prior art cells, the electrolyte layer is coated on the side edges of the innermost electrode and extends over the metal substrate to seal off gases within the porous region and the innermost electrode.

[0069] In FIG. 2 , each metal substrate 120 a, 120 b has a first side 125 and a second side 126, with a porous region 124 extending between them. The porous region 124 allows fluid on the second side 126 of the metal substrate 120 to reach one side of the electrochemically active layer 110 (the anode layer as shown). The electrochemically active layer 110 (comprising the anode layer 113, electrolyte layer 112, and cathode layer 111) is supported by the porous region 124. The second sides 126 of the two metal substrates 120 a, 120 b are attached to either side of one or more spacers 130 so that the cell units have similar sides arranged in a back-to-back configuration. This arrangement forms a first fluid volume 140 between the pair of metal substrates 120 a, 120 b. A support structure 131 may be disposed between the pair of metal substrates to react to any necessary compressive loads and for current collection from the outermost electrodes (see the description of FIG. 4a). In this manner, the anode layers 113 of the two cell units face each other across the entire first fluid volume 140. When the anode layers 113 (or fuel electrodes) of the two cell units face each other across the entire first fluid volume 140, the pair of metal substrates encases the fuel volume, and the support structure 131 is exposed only to the fuel. In this case, the support structure can perform a secondary function of supporting a catalyst required for internal reforming of the fuel. The volume must be sealed to prevent contact of the fuel gas with the oxidant gas.

[0070] To explain, a fuel (such as hydrogen or a hydrocarbon gas) needs to contact the fuel electrode or anode (in an SOFC) side of the cell unit, and an oxidant (such as air or oxygen) needs access to the air electrode or cathode side of the cell unit. Thus, when the anode is adjacent to the metal substrate, the fluid volume between the support plates (in this case, the "first fluid volume") is preferably for the fuel. However, in a back-to-back configuration, if the cathode layer 111 is instead deposited first, the first fluid volume needs to be the oxidant fluid volume.

[0071] Support structure 131 may be similar to interconnect 160 of FIG. 1b or interconnect 150a of FIG. 1c, but in this case it need not extend all the way to spacer 130. Furthermore, support structure 131 of FIG. 2 is exposed to only one environment (either fuel or oxidant) and does not need to separate the two environments. Therefore, fewer chemical, thermal, and mechanical demands are placed on the support structure than prior art designs. Furthermore, support structure 131 must be sufficiently open to allow fluid to pass from one side of support structure 131 to the other.

[0072] The support structure 131 may be, but need not be, electrically conductive. This is because the spacer 130 (which separates the two metal substrates in a pair of cell unit arrangement) may be electrically conductive, thus enabling electrical connection between the two metal substrates. The electrical connection through the spacer 130 may be assisted by welding or brazing through the metal substrates and the spacer. This welding or brazing also seals the first and second fluid volumes. Furthermore, because the electrical interconnection between the cells does not rely on the electrical connection between the support structure 131 and the metal substrate 120, the compressive load through the support structure (and therefore the strength of the support structure) may be reduced compared to the interconnect 150 in FIG. 1 . While the support structure 131 is shown schematically as a corrugated element, other pressed three-dimensional forms, mesh structures, or expanded metals may be used.

[0073] For clarity, ports in the metal substrate 120 that allow delivery of a fluid (typically fuel) to the first fluid volume 140 are not shown in FIG. 2 (and subsequent FIGS. 3-7). The ports through the metal substrate 120 may be sealed by gaskets or welding between the metal substrate and the spacer plate 130. The ports and spacers (or features formed around the ports) together form chimneys for transport of the first fluid through the stack. The port features or manifolds allow a portion of the fluid to exit the chimney and enter the first fluid volume 140. One or more of the chimneys provide an outlet for exhaust gases from the first fluid volume 140.

[0074] 3 shows another face-to-face arrangement of a pair of cell units 300. This arrangement includes a first electrochemically active layer 110a supported by a first metal substrate 120a and a second electrochemically active layer 110b supported by a second metal substrate 120b. Each pair of electrochemically active layers 110a, 110b has cell chemistry including a cathode layer 111, an electrolyte layer 112, and an anode layer 113, as described above. Each of the metal substrates 120a, 120b has a first side 125 and a second side 126 with a porous region 124 extending between them and on which the electrochemically active layers 110a, 110b are supported. The first sides 125 of the metal substrates 120a, 120b are attached to one or more spacer plates 130 on either side so that the electrochemically active layers 110a, 110b face each other inward in a face-to-face arrangement. This arrangement forms a first fluid volume 141 between the pair of metal substrates 120a, 120b. A conductive support structure 310 may be disposed between the pair of metal substrates. That is, the cathode layers 111 of the two cell units face each other across the entire first fluid volume 141 to form the first fluid volume 141. In this case, the first fluid volume 141 is typically an oxidant (air or oxygen) volume. The conductive support structure 310 is similar to the support structure 131, except that the conductive support structure 310 acts as a current collector to conduct current from the (outermost) electrode layer distal to the metal substrate 120, in this case the cathode layer 111.

[0075] Support structure 131 and conductive support structure 310 are shown schematically as corrugated elements, although again, other stamped three-dimensional features can be used. These features can serve to make electrical connections between adjacent cell units, and in doing so, the support structure and conductive support structure serve to resist buckling or warping of the metal substrates on either side. Support structure 131 and conductive support structure 310 preferably have gaps (not visible in the cross-sectional view shown) for the free flow of fluid through them from left to right (or right to left, or front to back, or back to front) and up and down (or bottom to top, or towards and away from the metal substrate) of the drawing, i.e., these structures are permeable.

[0076] FIG. 4a shows a bank 400 of cell units comprising two pairs of solid oxide cells 200a, 200b, each pair mounted back-to-back according to either of FIG. 2 (the bank comprises a first pair of electrochemically active layers 110a, 110b and a second pair of electrochemically active layers 110c, 110d). Two (or more) pairs of cell units are stacked one on top of the other with one or more gaskets 180a, 180b between them. The gaskets 180a, 180b connect the first fluid volumes of adjacent cell pairs while sealing the first fluid volume from the second fluid volume. The current collector on the outermost electrode 310 is located within the second fluid volume 430 and may be similar to the conductive support structure 310 described above. The current collector may be an atmospheric current collector.

[0077] FIG. 4b shows a bank of cell units similar to that of FIG. 4a, but with support structures 131 shown as short spacers positioned inside first fluid volumes 140a, 140b. Support structures 131 are electrically conductive so as to electrically connect the respective metal substrates on both sides (however, the support structures need not be—this function can be provided at the edges, as will be explained). Support structures 131 may be separate components from metal substrate 120, or may be formed by stamping or forming features on the metal substrate, provided that support structures 131 are external to the cell chemistry. Support structures 131 may also act to prevent bending or flexing of metal substrate 120 as a result of the compressive forces required for current collection.

[0078] 4b shows a typical separator layer 440 in place of the conductive support structure 310. The separator layer 440 may comprise a mesh, expanded metal, or a combination thereof. The separator layer is disposed within the second fluid volume 430 and provides interconnection between the second cell unit 110b of the first pair of cell units 200a and the first cell unit 110c of the second pair of cell units 200b. The layer 440 has spaces or gaps for the flow of oxidant (or fuel, as the case may be).

[0079] FIG. 5 shows a stack 500 of cell units comprising two or more banks 400a, 400b of cell units 200a, 200b stacked one on top of the other. Each bank 400a, 400b is similar to the bank 400 of FIG. 4a or 4b. The stack further comprises an insulating layer 510 disposed between each pair of banks 400a, 400b to electrically isolate the banks from each other. A conductive support structure 530 is provided to contact the electrochemically active layer 110 and act as a current collector (for the cathode layer when the first fluid volume is a fuel volume (e.g., hydrogen in the case of an SOFC) and the second fluid volume is an oxidant volume). Additional banks may be added to the stack by repeating the conductive support structure 530 and insulating layer 510.

[0080] Two pairs of cell units are shown in each bank 400a, 400b in Figure 5. However, a pair of cell units or more than two pairs of cell units may be used. See Table 1 (below).

[0081] FIG. 6 shows a stack 600 of two banks of cell units similar to those shown in FIGS. 4a, 4b, and 5 (more such banks may exist, but only two are shown). Bus bars 610, 615, and 620 are provided. Bus bar 610 connects the conductive spacer plates 130 between the metal substrates 120 of each pair of cell units in the first bank 400a (and thus to the metal substrates of the conductive spacer plates 130). Thus, in general, bus bar 610 electrically connects the anodes of the first bank. Bus bar 615 connects the conductive support structures 630 between the electrochemically active layers 120 of the second bank 400b. Thus, in general, bus bar 615 electrically connects the cathodes of the second bank. Bus bar 620 connects the conductive support structures 630 of the first bank 400a to the conductive spacer plates 130 of the second bank. Thus, in general, busbar 620 electrically connects the cathodes of the first bank with the anodes of the second bank. The busbars are preferably welded to their respective separator plates 130 and conductive support structures 630. Separator plates 130 are shown extended outward to face busbars 610, 620; alternatively, metal substrate 120 may be extended to face and electrically connect busbars 610, 620. Busbars 610, 615 may be connected to further cell units of an adjacent bank (not shown) and thus may have a similar arrangement to busbar 620. Alternatively, busbars 610, 615 may not be connected to an adjacent bank of cell units, but instead may be connected to a power take-off to route power from the stack for external use.

[0082] In this way, a parallel-series arrangement of cell units is achieved. All anodes of a particular bank are connected in parallel. Similarly, all cathodes of a particular bank are connected in parallel. This helps to meet the current requirements imposed on the stack of cell units. Cell units of one bank are connected in series with cell units of an adjacent bank. The cathodes of a bank (e.g., the first bank 400a) are connected in series with the anodes of an adjacent bank (e.g., the second bank 400b). This helps to meet the voltage requirements imposed on the stack. More banks may be added to further increase the voltage.

[0083] 7a shows more schematically a stack 700 of two banks 710a, 710b of cell units. The stack comprises banks of cell units stacked on top of each other with an insulating layer 510 disposed between each pair of banks 710a, 710b. Further banks may be added to the stack 700 by repeating the insulating layer 510 and the banks 710.

[0084] Each bank comprises multiple pairs of cell units. In the illustrated example, there are three pairs of cell units in each bank. However, one, two, or more than two pairs of cell units may be used. See Table 1 (below).

[0085] FIG. 7a is simplified relative to FIG. 6 to show the electrical connections of the cell units between banks. Again, all anodes of a particular bank are connected in parallel. Similarly, all cathodes of a particular bank are connected in parallel. This helps meet the current requirements imposed on the stack of cell units. Cell units of one bank are connected in series with cell units of an adjacent bank. The cathodes of a bank (e.g., the first bank 710a) are connected in series with the anodes of an adjacent bank (e.g., the second bank 710b). This helps meet the voltage requirements imposed on the stack.

[0086] Figure 7b shows a stack of two banks of cell units similar to the banks described in connection with Figures 6 and 7a. The stack further includes conductive gaskets 730a, 730b disposed between the metal substrates of adjacent pairs of cell units to deliver fuel between the cell pairs. The conductive gaskets 730 function as the busbars 610 of Figure 6 in electrically connecting the anodes of the banks of cell units. A busbar 720 is then used to connect the cathodes of the first bank to the anodes of the second bank. A busbar 715 generally electrically connects the cathodes of the second bank (and may connect to the anodes of additional banks (not shown)).

[0087] Two banks with three pairs of cell units each are shown in Figure 7b, however, one, two, or more than two pairs of cell units may be present in each bank, and stacks with multiple banks may be formed.

[0088] Figure 7c shows a stack 750 of two banks of cell units as described in relation to Figure 7b, further comprising a solid block 731 positioned between the conductive support structures 630 which are themselves between each pair of cell units. The solid block 731 electrically connects the first and second banks of cell units, as previously described, eliminating the need for bus bars and welding of the bus bars to the stack of cell units.

[0089] [Table 1] Table 1 shows the increase in volumetric power density compared to the prior art design of FIG. 1 as a function of the number of cell units in the bank when the cell units are operated as MS-SOFC units. When operated in MS-SOFC mode, having a bank of just two cell units (i.e., a pair of cell units in a back-to-back or face-to-face arrangement) increases the volumetric power density by 19%. This is because one fluid volume is shared by two electrochemically active layers on two metal substrates 120. Therefore, the height of the shared fluid volume can be reduced compared to the combined height of the two fluid volumes in the prior art design due to the reduced amount of viscous losses caused by frictional effects at the walls of the fluid volume.

[0090] As will be appreciated by those skilled in the art, these advantages apply equally to operating the cell unit as an MS-SOEC unit.

[0091] The volumetric power density increases for banks with four cells (i.e., two pairs of cell units in a back-to-back or face-to-face arrangement) because for a given number of cells in the stack, fewer insulating layers (which increase the stack height) are required between the banks.

[0092] The increase in volumetric power density is less pronounced, such as when increasing from two pairs of cell units to three pairs of cell units per bank. Furthermore, as the number of cell units per bank increases, the current generated by the bank also increases. This can be advantageous in high-current applications, but it can also increase resistive losses and require components to be made of thicker or more conductive materials to withstand or mitigate resistive heating.

[0093] The metal substrate may be completely flat, so that it lies entirely in a single plane, or, as described below, may be pressed or formed so that beyond the cell chemistry layers, the substrate has 3D features, which may be formed before or after deposition of the cell chemistry.

[0094] Spacerless cell unit pair modified example The next embodiment, shown in Figures 8-10, illustrates cell unit pairs according to the present invention. In this case, the cell units are directly connected to each other so that they abut each other; these pairs may be referred to as spacerless cell unit pairs. To achieve the necessary common fluid volume between the cell units, each metal substrate is not flat, but rather forms a 3D feature (e.g., pressed or stamped) that eliminates the need for spacers to form the fluid volume between the cell units. These examples are shown with a back-to-back arrangement as an example. The spacerless cell unit pairs in Figures 8-10 are not drawn to scale; rather, the ends with ports may be shown in more detail due to discontinuities (not fully shown) in the active cell chemistry. For clarity, the actual ports through the metal substrate 120 are not shown.

[0095] FIG. 8a shows a cell unit 810 comprising an electrochemically active layer 110 deposited or coated on a metal substrate 120 (in the figure, the active layer and substrate are truncated in the center to focus on the edges). The thin electrochemically active layer 110 is again placed on a supporting metal substrate 120, as previously described. The second side 126 of the metal substrate 120 forms (e.g., pressed or stamped) features or protrusions 840 extending from its surface (downward as shown). The protrusions 840 are shown as triangular (i.e., three-dimensional cones or pyramids) but may have other cross-sectional shapes, such as domes or ridges, and may have peaks. The protrusions 840 are distributed around ports (not shown) to allow fluid to flow from the ports to a first fluid volume or from the first fluid volume to the ports (i.e., to allow fluid movement between the ports and the fluid volumes). In this way, the protrusion transfers the stack compressive load around the port while keeping the necessary fluid channel open from the fluid chimney to the first fluid volume.

[0096] The apex or peak of the protrusion (or substrate-formed feature) 840 extends away from the second side 126. The metal substrate 120 further includes a formed feature comprising a flange 850 on its periphery. The flange is oriented in a plane parallel to and perpendicularly spaced from (lower than) the major plane of the metal substrate 120. The major plane of the metal substrate 120 is the plane that supports the electrochemically-active layer 110. The protrusions 840 and flanges 850 are formed in the metal substrate 120 by pressing, stamping, or other methods of forming a planar metal substrate. The porous region and electrochemically-active layer 110 can be formed before or after the formation of the protrusions 840 and flanges 850, but preferably the protrusions 840 and flanges 850 are formed before depositing the electrochemically-active layer 110 to reduce the possibility of damage to the layer.

[0097] FIG. 8b illustrates a spacerless pair 805 of cell units in a back-to-back arrangement, with each cell unit 810a, 810b as described in connection with FIG. 8a. As shown, the pair includes first and second cell units. The first cell unit 810a and the second cell unit 810b are connected back-to-back, with the peak of a protrusion 840a extending from the first cell unit contacting or abutting a protrusion 840 extending from the second cell unit. The pair 805 of cell units forms a continuous fluid volume 140 between the first and second metal substrates. The volume is sealed around a peripheral flange 850 by welding, brazing, or a similar technique. As is apparent from FIG. 8b, the protrusion 840 and flange 850 eliminate the need for a spacer (e.g., spacer 130 of FIG. 4) between the cell units 810a, 810b in the back-to-back pair 805 of cell units.

[0098] FIG. 8c shows a bank 870 of cell units comprising two spacerless pairs of cell units, each pair 805a, 805b being as described in connection with FIG. 8b. As previously described, each bank may have one or more pairs of cell units. The pairs 805a, 805b of cell units are arranged in a stacked arrangement, one above the other, with one or more gaskets 180 providing fluid connection between the first fluid volumes of adjacent pairs, as previously described. As previously described, these gaskets are electrically conductive and can electrically connect the substrates of adjacent cell pairs. A conductive support structure 440 is provided between adjacent pairs of cell units to electrically connect the surfaces of the electrochemically active layers distal to the metal substrate 120 (e.g., to connect the cathodes (outermost electrodes) of the first pair of cell units 805a with the cathodes of the second pair of cell units 805b). The conductive support structure 440 is similar to the conductive support structure 440 described above and may comprise mesh, expanded metal, or may be similar to the conductive support structure 310. The support structure 131 may optionally be provided within the fluid volume 140, as described above.

[0099] 9a-9c show a modification of the cell unit of FIGS. 8a-8c. The cell unit of FIG. 9a is provided with a raised port feature 910 surrounding the fluid port 980. The raised port feature is preferably annular. The raised port feature has a plane parallel to and vertically spaced apart from the major plane of the metal substrate 120 (higher than the major plane in the illustrated direction). The plane of the raised port feature 910 is in the opposite direction from the major plane of the metal substrate to the plane of the flange 850. That is, the metal substrate has three levels, each of which is planar and vertically spaced apart. That is, the plane of the raised port feature 910 is above the major plane of the metal substrate, which is itself above the plane of the flange 850. The raised port feature 910 is formed in the metal substrate 120, preferably simultaneously with the protrusion 840 and flange 850, by pressing, stamping, or forming a planar metal substrate. The protrusions 840 and raised port features 910 are positioned to transfer stack compressive loads around the ports while keeping the necessary fluid channels open from the fluid chimney to the first fluid volume 140 .

[0100] Figure 9b shows a pair of cell units 905 as described in Figure 9a. The first and second cell units are arranged back to back, with the peak of the protrusion 840 extending from the second side of the first cell unit contacting or abutting the protrusion 840 extending from the second side of the second cell unit. The pair of cell units encloses a first fluid volume 140 between a first metal support plate and a second metal support plate. The height of the first fluid volume 140 is defined by the protrusion 840 and a flange 850 and is sealed by welding around the flange 850.

[0101] Figure 9c shows a bank 900 of cell units comprising two pairs of cell units, each pair 905a, 905b of cell units being similar to that shown in Figure 9a. As previously described, each bank may have one or more pairs of cell units, and banks may be stacked and electrically connected as previously described. The pairs 805a, 805b of cell units are positioned in a stacked arrangement, one above the other, with the stacked arrangement forming a second fluid volume 430 between adjacent pairs of cell units.

[0102] The raised port features 910 of adjacent cell pairs interact to separate the adjacent pair of cell units to form the second fluid volume 430. The height of the raised port features is sufficient to form the second fluid volume, thus further separating the electrochemically active layers 110 of the cell units in the first pair of cell units from the electrochemically active layers 110 of the cell units in the second adjacent pair of cell units. The raised port features 910 and ports 980 form a fluid chimney for delivering fluid to (or evacuating from) the first fluid volume 140.

[0103] The planar surface of the raised port feature of a first cell unit interfaces with the corresponding planar surface of the raised port feature of a second cell unit, with the second cell unit being paired with the first cell unit. Thus, in contrast to the previously described cell units, the raised port feature 910 eliminates the need for a gasket (such as gasket 180 described in connection with FIG. 4 ) between adjacent pairs of cell units to form the second fluid volume. These cell unit pairs may be referred to as gasketless, spacerless cell pairs, which can be formed into a stack with even fewer parts.

[0104] The interface between the flat surface of the raised port feature of the first cell unit and the corresponding flat surface of the raised port feature of the second cell unit must be sealed to seal the chimney and prevent mixing of the fluids in the first and second fluid volumes. The seal may be achieved using a gasket, i.e., a preformed gasket, or preferably, a sealing contact paste or liquid that forms a seal in situ. The latter may be placed in an annular groove in one or both of the interfacing flat surfaces. If necessary, an additional (e.g., compressible) annular gasket may be placed around the outside of the raised port feature—in effect, fixed in place. Alternatively, the seal may be achieved by welding a seal around the interfacing flat surface of the raised port feature, which preferably further reduces the number of parts.

[0105] FIG. 10a shows a variation of the cell unit of FIG. 9a. The raised port feature 1050 is moved radially outward from the outer periphery of the port 980 compared to the raised port feature 910 of FIG. 9. This allows the planes of the raised port feature 1050 to be supported radially inward and radially outward (relative to the port 980) by the protrusions 840, 1040. The raised port feature 1050 is an annular ring supported on both sides. Additional protrusions 1040 are shown, which are similar to the protrusions 840, except that they are positioned between the port 980 and the raised port feature 1050, while the protrusions 840 are positioned radially outward (relative to the port 980) of the raised port feature 1050. The raised port feature 1050 transmits compression through the stack of cells via the protrusions 840, 1040. In this way, the raised port feature 1050 is positioned to transfer the stack compressive load required for gasket sealing between the banks around the port while keeping the necessary fluid channel open from the fluid chimney to the first fluid volume 140 (see Figure 10d).

[0106] Figure 10b shows how a pair of such cell units can be arranged back to back so that further protrusions 1040 abut each other (in a similar manner to protrusions 840) and provide separation between the metal substrates to allow fluid to enter the first fluid volume 140 from the fluid chimney and port 980.

[0107] The protrusions 1040 are shown protruding into the first fluid volume 140. The protrusions can alternately protrude into and out of that volume, as described below. If the protrusions protrude away from the fluid volume 140, they protrude to the same level as the raised port feature 1050 and help share the stack compression load with the raised port feature 1050. The protrusions 840 can alternate as well.

[0108] Figure 10c shows such a bank of cell units and illustrates how the raised port features 1050a of one pair of cell units abut the raised port features 1050b of an adjacent pair of cell units. As described in relation to Figure 9c, the raised port features interact and are sealed to define a chimney.

[0109] Figure 10d shows two banks of pairs of cell units in a stacked arrangement. Between the banks of cell units, an insulator layer 1070 is provided, separating and electrically insulating adjacent planar surfaces of the raised port features 1050. The insulator layer 1070 (e.g., an electrolyte layer) may be similar to the insulating layer 510 (described above in connection with Figure 5) or may be in the form of an insulating paste. An additional gasket 1080 is provided inside the chimney, positioned radially inward (relative to the ports 980) of the opposing raised port features 1050a, 1050b of adjacent banks, and positioned above the protrusions 1040 to seal them and transmit compressive forces through the stack. Alternatively, an annular insulator 1080 may be provided outside the chimney, positioned radially outward (relative to the ports 980) of the opposing raised port features 1050a, 1050b of adjacent banks, and positioned above the protrusions 840 to transmit compressive forces through the stack. The insulating layer 1070 and insulating gasket 1080 act together or individually to seal the fluid chimney (thus defining a first fluid volume separate from a second fluid volume), provide electrical insulation between the banks, and transmit compressive forces through the stack. The insulating layer may be selected so that it meets all of these requirements, and the gasket 1080 may be omitted to further reduce parts count. The cell units of FIGS. 9a-9c may be formed into a bank arrangement similar to that of FIG. 10d. Furthermore, the banks in the bank arrangement of FIG. 10d may be electrically connected in the manner described in connection with FIGS. 6-7c.

[0110] FIG. 10e illustrates another electrical connection between two banks of pairs of stacked cell units. In this arrangement, a single cell unit 1020 is provided at the end of the bank (it may be at the top or bottom of the bank, as shown). The single cell unit 1020 is similar to the cell unit described in connection with FIG. 10a. The single cell unit 1020 is attached (e.g., by welding or brazing) to a non-porous metal sheet 1021 to form an enclosed fluid volume between the single cell unit 1020 and the non-porous metal sheet 1021 (i.e., there is no fluid communication from one side of the non-porous metal sheet 1021 to the other side of the non-porous metal sheet 1021, except through ports through the non-porous metal sheet 1021 corresponding to the ports of the cell unit 1020). A spacer 131 is disposed within the enclosed fluid volume between the single cell unit 1020 and the non-porous metal sheet 1021, and the spacer 131 is as described above. The non-porous metal sheet 1021 is an unperforated metal substrate that does not have any active cell chemistry layers. The non-porous metal sheet 1021 incorporates holes for forming fluid-compatible ports in the cell units 1020. Although the non-porous metal sheet 1021 is shown as a flat, unformed sheet, it may also have port features formed in the same manner as the cell units 1020.

[0111] As is clear from Figure 10e, and in contrast to Figure 10d, there is no insulator layer 1070 separating the banks across their width. The conductive support structure (separator 440) at the end of a first bank directly contacts the non-porous metal sheet 1021 at the end of the adjacent second bank. The conductive support structure (separator 440) is as described above. An insulator layer or insulating gasket 1071 disposed on the raised port feature 1050 of the cell unit at the end of the first bank electrically insulates the raised port feature 1050 from the non-porous metal sheet 1021 at the end of the adjacent second bank and seals the fluid within the manifold. Thus, adjacent banks are connected in series (via separator 440) in face-to-face contact across most of the cell area without the need for further electrical connections. For example, a bank may have all of its conductive support structures (or interconnects) connected in parallel, and the outermost conductive support structure (separator 440 or interconnect) may be in contact (physically and electrically) and connected in series with the non-porous metal sheet of an end pair of units (a pair comprising a non-porous metal sheet 1021 and a cell unit 1020) of an adjacent bank. In that adjacent bank, the non-porous metal sheet and substrate are at the same potential and connected in parallel with all other metal substrates in that bank. Thus, the parallel-connected substrates in the adjacent bank are connected by a series connection to the parallel-connected interconnects in the first bank.

[0112] End pairs of units of a bank (pairs comprising a non-porous metal sheet 1021 and cell unit 1020, as in Figure 10e) may be used in the bank of cell unit pairs described in connection with Figures 2 to 9. In the devices described in connection with Figures 6 and 7a-7b, the use of single or unpaired cells results in shorter bus bars 610, 615, 620, 710, 715, 720, as the bus bars are not required to electrically interconnect adjacent banks. As before, the bus bars still connect the pairs of cell units within each bank.

[0113] Assembly method (for spacerless cell unit pairs) By way of example, one preferred method of assembling the novel device of spacerless pairs of cell units will now be described with reference to Figures 11-15.

[0114] As shown in FIG. 11 , the cell unit comprises a metal substrate 120 having an uppermost first side and a lower second side. The metal substrate comprises a porous region 124 with an electrochemically active layer on the underside. The electrochemically active layer comprises a cathode layer, an electrolyte layer, and an anode layer, as previously described. FIG. 11 shows a portion of the cell unit; the extent of the unit has been cut off (on the right as shown) for clarity; it will be appreciated that a working version of the unit continues beyond the right side of the image, with the extended metal substrate and electrochemically active layer surrounded by a flange that forms a continuous perimeter of the cell unit. Additional ports may be present.

[0115] Two ports 980a, 980b are shown in the cell unit. The ports are holes that penetrate the metal substrate 120. Radially outward from each port is an annular raised port feature 1050 (shown in FIG. 11 as a valley or recessed ring). Protrusions 1040 are provided radially inward from the raised port features 1050. The protrusions 1040 alternate upward and downward and are shown as flat-topped pyramids, but may have other cross-sectional shapes, such as cones, domes, or protrusions, and may have rounded tops. The raised port features 1050 are further surrounded by upward protrusions 840 around and radially outward from the raised port features 1050. The protrusions 840 are shown as raised protrusions or domes, but may have other cross-sectional shapes, such as conical flat-topped pyramids (possibly interspersed with downward protrusions).

[0116] The cell pair assembly process begins by stamping or pressing a metal substrate into a predetermined shape to form the first cell unit (as described in the previous embodiment) and forming the port hole peripheral flange 850, protrusions 840, 1040, and raised port feature 1050 (protrusion 840 protruding on the same side / in the same direction as flange 850, raised port feature 1050 protruding on the opposite side / in the opposite direction).

[0117] The porous region 124 and electrochemically active layer 120 may be formed by the methods described above with respect to FIGS. 1 and 2 either before or after (the latter is preferred) stamping or pressing the metal substrate.

[0118] The port holes may be referred to as fuel ports because, when operated as an MS-SOFC, they route fuel (e.g., hydrogen gas) into the first fluid volume, and, when operated as an MS-SOEC, they route gas, e.g., hydrogen gas (as a product of the MS-SOEC cell unit), from the first fluid volume.

[0119] A second such cell unit is provided, inverted, and positioned over the first cell to form a first pair of cell units in a back-to-back arrangement, as shown in Figures 12a and 12b. Figures 12a and 12b show a first metal substrate 120a and a second metal substrate 120b positioned above the first metal substrate 120a. The two metal substrates 120a, 120b are welded to each other along weld line 1210 on flange 850 to form the pair of cell units. Optionally, a spacer (such as spacer 131) is placed in the first fluid volume before the second cell unit is provided to the first cell unit.

[0120] Figure 12b is a cross-sectional view through the port area of ​​the cell unit pair of Figure 12a. The protrusions 1040 alternate direction (towards and away from the gap between the metal substrates 110a, 110b that make up the cell unit pair) to transmit compressive forces through the stack of cell units.

[0121] Once sealed, the inwardly projecting protrusions 1040 around the inner periphery of the annular raised port forms 1050 of the first and second cell units contact each other in an opposed relationship, as can be seen in the cross-section of Figure 12b (a cross-section of a chimney providing inflow or outflow to the first fluid volume, generally indicated by circle 1200). The same is true for the protrusions 840 around the periphery of each annular raised port form 1050.

[0122] The method for assembling a cell bank as described above in any of the previous embodiments follows the sequence shown in FIGS.

[0123] As shown in FIG. 13, a bank of cell units comprises one or more pairs of cell units formed using the method described in connection with FIGS.

[0124] The bank assembly process begins with placing a conductive support structure 310 over the first cell pair assembly and in contact with the electrochemically active layer 110 to provide electrical connection to the upper layer of the electrochemically active layer 110. The conductive support structure 310 is positioned so that it extends beyond the edges of the metal substrate on one or more sides and does not interfere with the chimneys formed by the ports and raised port features.

[0125] The conductive support structure may be a stamped metal plate similar to conductive support structure 310 described above, or may be a conductive mesh or similar form (as described above in connection with separator 440).

[0126] FIG. 14a shows a third cell unit having a metal substrate 120c positioned over the first cell pair assembly such that the conductive support structure 310 contacts the electrochemically active layer of the third cell unit. The annular raised port features 1050c and outward protrusions 1040 of the third cell unit contact the corresponding annular raised port features and outward protrusions 1040 of the first cell pair assembly. FIG. 14b shows a cross section through the port area of ​​the cell unit of FIG. 14a. The third cell unit is then welded to the first cell pair assembly around the raised annular port features 1050b, 1050c, which contact along a weld line to form a seal between the port holes 980a, 980b of the first cell pair assembly and the third cell unit.

[0127] 15a, edge tangs 1510 are also provided outside the periphery of the cell substrate to electrically connect adjacent conductive support structures 310. The electrical connection between the edge tangs of adjacent conductive support structures can be improved by welding through the interface of the edge tangs.

[0128] Additional cell units can be added in the manner described with respect to Figures 11-14 until the bank reaches the desired number of cell unit pairs. In such a bank, no gaskets are required to form seals around the fluid ports between cell pairs, and the cells form a complete welded assembly. Instead of adding a single cell unit in Figure 14, pairs of cell units (shown in Figure 12) can be placed on each conductive support structure 310, although this makes welding around the fluid ports more difficult.

[0129] Figure 15a shows a bank of cell units comprising three pairs of cell units formed using the method described above, and Figure 15b is a cross-sectional view through the chimney region of the bank of cell units of Figure 15a.

[0130] The conductive support structure 310 preferably comprises tangs (metal fingers) 311, as shown in Figure 14b. The tangs are stamped in rows from a flat metal sheet. For example, alternating tangs in a row are stamped upward and downward from the plane of the sheet. The tangs serve as electrical contacts to electrically interconnect opposing surfaces with the electrochemically active layers.

[0131] A further step in the method of assembling a cell stack will now be described with reference to Figure 15c. As shown in Figure 15c, the stack of cell units includes a plurality of bank assemblies formed as described above in connection with Figures 11-15b. A conductive support structure, an insulating layer, and a second conductive support structure are disposed on the bank of cell units of Figure 15, and a second bank of cell units (similar to that of Figure 15) is disposed thereon. Figure 15c shows two banks of cell units separated by an insulating layer 1070 similar to that of Figure 10d. The annular raised port features and the protrusions between the banks are also electrically isolated, similar to those shown in Figure 10d. The edge tongues of the first bank of cell units do not connect to the edge tongues of the second bank of cell units similar to those of Figures 6-7.

[0132] Cell unit pair formed by folding 16 and 17 show another apparatus for forming pairs of cells in a back-to-back or face-to-face arrangement (not shown). In this apparatus, at least one pair of cell units is formed by depositing the active layers of each of the opposing cell units on a common substrate and bending the metal substrate so that the active layers are supported by the common substrate. Because the metal substrate is conductive, the electrodes closest to the metal substrate are electrically connected to the same potential.

[0133] FIG. 16a shows a pair of folded cell units 1600a, 1600b in a device in which the metal substrate 120 is U-shaped. The metal substrate 120 is formed from a single metal plate or continuous metal substrate that is folded 180 degrees at a folding zone 1620. The metal plate is provided with two porous regions and two electrochemically active layers 110a, 110b sealingly overlaying the porous regions at two respective locations on a first side 125 of the metal plate, with the folding zone 1620 between the two electrochemically active layers 110a, 110b. In the case of a SOFC, the two porous regions and the associated electrochemically active regions 110 are separate, i.e., distinct. That is, the electrochemically active regions 110 are not deposited in the area of ​​the folding zone 1620 because the electrochemically active regions 110 are inflexible.

[0134] 16a, the electrochemically active layers lie on top of each other in a back-to-back (or face-to-face) arrangement, occupying respective substantially parallel (flat) planes, once folded through 180 degrees in the folding zone 1620. The folding zone 1620 at the folding end of a pair of folded cell units may comprise two 90-degree folds with a short section between them, which provides the height of the first fluid volume 140.

[0135] Ports may be formed in the substrate 120 between the electrochemically active region 110 and the folding zone 1620 (and at the other end of the folded substrate between the electrochemically active region 110 and the edge of the substrate) to form chimneys for supplying (and / or discharging) the first (and / or second) fluid volumes, thus manifolding the first (and / or second) fluid volumes internally.

[0136] The first fluid volume 140 may be sealed at the other end 1630 (i.e., the end distal to the bending zone 1620) using a (e.g., conductive) spacer such as spacer 130 welded to the metal substrate 120, as further described with respect to Figure 16b.

[0137] The arrangement of cell unit pairs 1600 forms a repeating unit and may be used in place of cell pairs 200 in the cell bank described in connection with FIGS.

[0138] As mentioned above, the electrochemically active layers, when used in a solid oxide cell, typically comprise an anode layer 113, an electrolyte layer 112, and a cathode layer 111 deposited on a porous region 124, and there may also be an extended electrolyte coating 123. A metal substrate (of the same polarity as the innermost electrode) may be connected to an electrical connection (not shown).

[0139] FIG. 16b illustrates how folded pairs of cell units 1600a, 1600b are stacked together to form a bank 1640 of cell units. The bank 1640 is similar to the banks described in connection with FIGS. 4-10. Each folded pair of cell units 1600a, 1600b has a spacer 130 or gasket that seals the first fluid volume 140. Gaskets 180a, 180b (which may be conductive as described above) and conductive support structures 310 are positioned between adjacent folded pairs 1600a, 1600b. Between the pairs, the gaskets 180a, 180b seal internal manifolds that provide fluid communication between adjacent cell pairs to the first fluid volume. The conductive support structure 310 makes electrical contact with the outermost electrodes of the electrochemically active layers 110 of adjacent folded units 1600a, 1600b, which are of opposite polarity to the metal substrate, and may also be connected to an electrical connector (e.g., for power take-off). A support structure (not shown) may be provided in the first fluid volume 140 to resist bending of the metal substrate 120. As described above in connection with Figures 5-10, two or more banks 1640 may be arranged.

[0140] 16c shows a folded pair 1650 of cell units in a back-to-back arrangement, including formed port features 840, 910, and 1040 and a peripheral flange 850. The formed port features maintain chimneys for delivery and evacuation of the first fluid volumes 140, eliminating the need for gaskets 180a and 180b. Thus, the device has internally manifolded first fluid volumes (i.e., ports and formed port features define inlets to and outlets from the first fluid volumes 140 of each pair of cell units). The second fluid volume may be similarly internally manifolded (i) with additional ports and formed port features providing inlets to and outlets from a second fluid volume (not shown), or may be externally manifolded with a second fluid flow around the periphery of the pair of cell units.

[0141] The folded pair of cell units 1650 may be substantially similar to the pair of cell units described in connection with FIGS. 9b, 10b, and 16a, except for the presence of a folding zone 1620 at one end of the peripheral flange 850. The folding zone 1620 is shown as replacing one end of the peripheral flange 850. At least the opposite end of the folding zone 1620 is the peripheral flange 850, preferably around all three edges of the (e.g., rectangular) cell. Alternatively, the peripheral flange 850 may be held at all edges of the cell (e.g., all four edges of a rectangular cell), with the folding zone 1620 integrated into the flange 850 (as shown in FIG. 17b), and a weld may be made around the perimeter of the peripheral flange 850 to seal the first fluid volume 140.

[0142] The cell unit pair 1650 is formed from a metal sheet with a formed feature that is folded at the folding zone 1620. The formed feature is formed by stamping a flat metal sheet. The formed feature includes a protrusion 840 (in the form of a recess) around the chimney, a chimney protrusion 910 (annular and can be used with or without a gasket to seal the chimney), and a protrusion 1040 on the outside of the chimney. The protrusions 840, 1040 help define the first fluid volume 140 by resisting stack compression forces. A support structure 131 may be positioned between the porous regions of the substrate 120 to prevent bending of the substrate 120 and define the first fluid volume 140. The electrochemically active layer 110 may be deposited on the porous region 124 of the metal substrate 120 before or after folding the metal sheet.

[0143] 17a shows another arrangement of a cell unit 1700 in which four electrochemically active regions 110 share the same metal substrate 120. The metal substrate 120 is formed from a single metal plate or continuous metal substrate that is folded at folding zones 1720a, 1720b, and 1720c. The single metal plate is provided with four porous regions, over which four electrochemically active regions 110 are deposited on the first side 125, respectively. In the case of a SOFC or SOEC, the four porous regions and the electrochemically active regions 110 are separate. The metal substrate 120 is formed by bending a single metal plate 180 degrees in a first direction (clockwise as shown in FIG. 17a) in the first bending zone 1720a, bending a single metal plate 180 degrees in a second direction (counterclockwise as shown in FIG. 17a) in the second bending zone 1720b, and bending a single metal plate 180 degrees in the first direction (clockwise as shown in FIG. 17a) in the third bending zone 1720c. As shown in FIG. 17a, this results in a back-to-back arrangement. Bending in the opposite direction (i.e., counterclockwise in the first and third bending zones, clockwise in the second bending zone) can result in a face-to-face arrangement. Thus, the metal substrate 120 forms a zigzag configuration. The first and third fold zones 1720a, 1720c define the first fluid volume 140, and the second fold zone 1720b defines the second fluid volume 430. Each fold zone 1720 may comprise two 90-degree folds with a short section between them that provides the height of the first and second fluid volumes 140, 430, respectively.

[0144] While the support structures 131 can assist in connecting opposing electrodes from adjacent electrochemically active layers 110, their primary role is to define the first fluid volume 140. The current collectors 310 collect current from opposing (outermost) electrodes from adjacent electrochemically active layers 110 and define the second fluid volume 430. (The support structures are not shown in the first fluid volume, but are shown in FIG. 17a in the second fluid volume, where they electrically connect the outermost electrodes of the active layers (optionally with contact paste).) As will be appreciated by those skilled in the art, a single metal plate may be provided with virtually any number of electrochemically active areas and a corresponding number of folding zones to provide a corresponding number of paired cell units in the zigzag cell. The limiting factor is typically the amount of current that can be drawn from multiple cells on a common substrate.

[0145] The arrangement of cell units 1700 on a single metal substrate 120 may be used as a single bank, optionally with spacers 130 or gaskets at the edges to seal the first fluid volume 140. As previously mentioned, multiple banks may be arranged to form a stack of cell units.

[0146] FIG. 17b shows an arrangement of cell units 1750 in a back-to-back arrangement, including formed port features 840, 910, and 1040 and a peripheral flange 850. The cell unit pair 1750 is substantially similar to the cell unit pairs described in connection with FIGS. 9b, 10b, and 17a. The fold zone 1720 is shown as forming part of the peripheral flange 850, or the fold zone can replace part of the peripheral flange (as shown with respect to fold zone 1620 in FIG. 16c). The peripheral flanges need not be welded at the first and third fold zones 1720a, 1720c, although the flange adjacent the second fold zone 1720b is welded to seal the first fluid volume 140.

[0147] As shown in FIG. 17b, two pairs of cell units 1750 are formed from a single metal sheet with formed features that are folded at folding zones 1720. The formed features are formed by stamping a flat metal sheet. The formed features include a protrusion 840 (in the form of a depression) around the chimney, a chimney protrusion 910 (annular and can be used with or without a gasket to seal the chimney), and a protrusion 1040 on the outside of the chimney. The protrusions 840 and 1040 help define the first fluid volume 140 by resisting stack compression. The chimney is used to deliver fuel (e.g., hydrogen gas) to the first fluid volume 140 when the cell unit is operated as an SOFC and to evacuate fuel (e.g., hydrogen gas) from the first fluid volume 140 when the cell unit is operated as an MS-SOEC. A second chimney may be used to evacuate the first fluid volume when the cell unit is operated as an MS-SOFC and to supply fluid to the first fluid volume when the cell unit is operated as an MS-SOEC. Conductive support structures 310a may be positioned between the porous regions of the substrate 120 to prevent bending of the substrate 120 and define the first fluid volume 140. Conductive support structures 310b may be positioned between the electrochemically active layers 110 to facilitate electrical interconnection between the electrochemically active layers 110 and to prevent bending of the substrate 120 and define the second fluid volume 430. The electrochemically active layers 110 may be deposited on the porous regions 124 of the metal substrate 120 before folding the metal sheet. Two pairs 1750 of cell units described in connection with FIG. 17b may be used as a single bank of cell units, or multiple banks may be arranged to form a stack, as previously described herein.

[0148] The stacks of folded pairs of cell units are internally manifolded, i.e., they have ports in the metal substrate 120 to form internal manifold(s) or chimneys connecting the first fluid volumes 140 of each pair of cell units. [Explanation of symbols]

[0149] Prior Art - Preface Section Only 90 fuel cell repeat units 110 Electrochemically active layer 111 Cathode layer 112 Electrolyte layer 113 Anode layer 120 Metal Substrate 124 Porous region 130 spacer plate 140 first fluid volume 150 Interconnection 160 Wide space / opening 180a, 180b gasket 188 Oxidizer Port / Manifold 200 ports / manifold Figure 2-Figure 17 110 Electrochemically active layer 111 Cathode layer 112 Electrolyte layer 113 Anode layer 120 Metal Substrate 123 Extended Electrolyte Coating 124 Porous region 125 First side of metal substrate 126 Second side of metal substrate 130 spacer 131 Support structure 140 first fluid volume 141 first fluid volume 180 Gasket 200 cell unit pairs 300 cell unit pairs 310 Conductive support structure / current collector 311 Interconnection tongue 400 cell unit bank 430 second fluid volume 440 Conductive Support Structure 500 cell unit stack 510 Insulating layer 530 Conductive Support Structure 610 Busbar in electrical contact with anode 615 Busbar in electrical contact with cathode 620 Busbars in electrical contact with the anode and cathode 630 Conductive Support Structure 700 cell unit stack Bank of 710 cell units 711 Busbars in electrical contact with anode and cathode 715 Busbar in electrical contact with anode 720 Busbars in electrical contact with anode and cathode 730 Conductive Gasket 731 Conductive Gasket 750 cell unit stack 805 cell unit pairs 810 Molded cell unit 840 protrusion 850 flange Bank of 870 cell units 905 cell unit pairs 910 Raised port form part 980 fluid port 1020 cell units 1021 Non-porous metal sheet 1040 Protrusion inside chimney 1050 raised port form 1070 insulating layer 1071 Insulating layer / insulating gasket 1080 Insulation Gasket 1200 Chimney 1210 Welding Path 1600 cell unit pair 1620 bending zone 1630 End of cell unit pair Bank of 1640 cell units 1650 cell unit pairs 1700 cell units 1720 bending zone 1750 cell units

Claims

1. At least one pair of cells; each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; the plurality of internal passages are sealingly defined by a plurality of gaskets disposed between pairs of the cells within the bank; Metal-supported planar cell device.

2. 10. The cell apparatus of claim 1, wherein a pair of metal substrates comprises two separate metal plates directly or indirectly connected to each other in said stacked arrangement.

3. A fuel cell comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; a pair of metal substrates comprising two separate metal plates connected to each other directly or indirectly in said stacked arrangement; A cell arrangement wherein said two metal plates are indirectly connected to each other, optionally with a metal spacer plate disposed therebetween, to form said stacked arrangement.

4. 3. The cell apparatus of claim 2, wherein the two metal plates are directly connected to each other so that they abut each other in the stacked arrangement, and one or both of the two metal plates has a molded form that forms the first fluid volume between the two plates.

5. A fuel cell system comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; a cell device, wherein a plurality of the metal substrates are formed as a single continuous metal substrate having a first side, a pair of cell chemistry layers are coated or deposited on the first side respectively over the porous region, and the continuous metal substrate is folded between the plurality of cell chemistry layers so that they overlie each other to form a folded pair of cells that define the first fluid volume for the one of fuel or oxidant.

6. 6. The cell apparatus of claim 5, comprising a plurality of folded cell pairs stacked next to each other in a plurality of said bank of cells.

7. 7. The cell device of claim 6, wherein each pair of folded cells in the bank is formed from a separate respective metal substrate, the substrate being folded once so that it has only one folded end that encloses the first fluid volume.

8. 7. The cell device of claim 5 or 6, wherein adjacent pairs of folded cells in the bank are formed from a common continuous metal substrate that is folded multiple times so that it has multiple opposing folded ends to define multiple respective first fluid volumes for the one of fuel or oxidant.

9. A fuel cell system comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; a cell apparatus, wherein at least one of the plurality of metal substrates includes a flanged perimeter feature, and wherein the plurality of metal substrates are sealed together around the flanged perimeter feature to form the common first fluid volume therebetween.

10. 10. The cell device according to claim 1, wherein at least one fluid port is provided as an opening penetrating each of the plurality of metal substrates, and the fluid ports are aligned with each other in the stacking direction and communicate with the common first fluid volume portion.

11. A fuel cell system comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; at least one fluid port is provided as an opening through each of the plurality of metal substrates, the fluid ports being aligned with one another in the stacking direction and communicating with the common first fluid volume; a cell device, wherein at least one of the plurality of metal substrates is provided with a molded port feature formed around the port and extending inwardly within the common first fluid volume, and wherein elements of the molded port feature are laterally spaced from one another to define a fluid path from the port between the elements and to allow passage of fluid from the port to the common first fluid volume.

12. 12. The cell apparatus of claim 10 or 11, wherein at least one of the plurality of metal substrates is provided with a molded port feature formed around the port and extending outwardly away from the common first fluid volume.

13. A fuel cell comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; A cell apparatus, wherein a plurality of said inwardly facing sides define a first fluid volume for fuel.

14. The cell device of any one of claims 1 to 13, wherein the inwardly facing side surfaces are the second side surfaces of the metal substrates.

15. 15. The cell device of claim 1, wherein all of the fuel electrodes in the bank are electrically connected to each other, and / or all of the air electrodes in the bank are electrically connected to each other.

16. A fuel cell comprising at least one pair of cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides; a fuel electrode layer, an electrolyte layer, and a air electrode layer; and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; the plurality of metal substrates are arranged in a stack with their cell chemistry layers overlying one another such that both of their first sides or both of their second sides face inwardly in a spaced apart opposing relationship, whereby the inwardly facing sides define therebetween a common first fluid volume for one of fuel or oxidant; a plurality of pairs of cells stacked adjacent to one another to form a bank of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, the at least one second fluid volume being for the other of fuel or oxidant; adjacent first fluid volumes are in fluid communication with one another via a plurality of openings formed through a respective one of the plurality of metal substrates, the plurality of openings being aligned in a stacking direction to form a plurality of internal passages within the bank; A cell device wherein all of the pairs of cells in each of the banks are welded together and all of the substrates are electrically connected.

17. 15. The cell device of claim 1, comprising a plurality of banks of cells stacked on top of each other, the fuel electrodes in one bank being connected in series to the air electrodes in the next adjacent bank.

18. 15. The cell device of claim 1, comprising a plurality of banks of cells stacked on top of each other, with an insulating sheet disposed between adjacent banks to prevent direct electrical contact between the adjacent banks.

19. 15. A cell device according to any preceding claim, comprising banks of cells stacked on top of each other, with a single cell at an end of a bank, said cell making direct electrical contact with adjacent cells of said adjacent banks to connect said adjacent banks in series.

20. 1. A method for assembling a metal supported planar cell device, comprising: providing first and second cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides, a fuel electrode layer, an electrolyte layer, and a air electrode layer, and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; cutting a plurality of apertures through each of a plurality of said metal substrates to form at least one inlet port and at least one outlet port; inverting one of the plurality of cells relative to the other, whereby the plurality of metal substrates are in a stacked arrangement with their cell chemistry layers overlying one another such that both of their plurality of first sides or both of their plurality of second sides face inwardly in spaced apart opposing relationship to define a common first fluid volume for one of fuel or oxidant therebetween to form the cell device; providing at least one additional cell device in the same manner as the first said cell device; and stacking a plurality of said cell devices to form a bank of cells; Including, at least one second fluid volume is defined between a pair of adjacent cells, the at least one second fluid volume being for the other of fuel or oxidant, adjacent first fluid volumes are in fluid communication with one another through a plurality of openings disposed through a respective plurality of the metal substrates, the openings being aligned in a stacking direction to form a plurality of internal passages within the bank; the plurality of internal passages are sealingly defined by a plurality of gaskets disposed between pairs of the cells within the bank; method.

21. 21. The method of claim 20, further comprising electrically connecting all of the fuel electrodes in the bank or all of the air electrodes in the bank.

22. 22. The method of claim 20 or 21, further comprising stacking each of a plurality of said banks of cells to form a stack of cells.

23. A method for assembling a metal-supported planar cell device, comprising: providing first and second cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides, a fuel electrode layer, an electrolyte layer, and a air electrode layer, and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; cutting a plurality of apertures through each of a plurality of said metal substrates to form at least one inlet port and at least one outlet port; inverting one of the plurality of cells relative to the other, whereby the plurality of metal substrates are in a stacked arrangement with their cell chemistry layers overlying one another such that both of their plurality of first sides or both of their plurality of second sides face inwardly in spaced apart opposing relationship to define a common first fluid volume for one of fuel or oxidant therebetween to form the cell device; providing at least one additional cell device in the same manner as the first said cell device; and stacking a plurality of said cell devices to form a bank of cells; Including, at least one second fluid volume is defined between a pair of adjacent cells, the at least one second fluid volume being for the other of fuel or oxidant, adjacent first fluid volumes are in fluid communication with one another through a plurality of openings disposed through a respective plurality of the metal substrates, the openings being aligned in a stacking direction to form a plurality of internal passages within the bank; wherein a plurality of the metal substrates are formed as a single continuous metal substrate, and the inverting step includes folding the continuous metal substrate between a plurality of the cell chemistry layers to form folded pairs of cells overlying each other and defining the first fluid volume for the one of fuel or oxidant.

24. 24. The method of claim 23, wherein the plurality of cell chemistry layers of the pair of cells are coated or deposited over the first side, respectively, before the continuous metal substrate is inverted by folding to form the folded pair.

25. 25. The method of claim 24, further comprising forming a pre-fold on the metal substrate prior to coating or depositing a plurality of the cell chemistry layers.

26. A method for assembling a metal-supported planar cell device, comprising: providing first and second cells, each cell comprising a metal substrate having first and second sides and a porous region providing fluid communication between said sides, a fuel electrode layer, an electrolyte layer, and a air electrode layer, and a planar cell chemistry layer coated or deposited over and supported by said porous region on said first side; cutting a plurality of apertures through each of a plurality of said metal substrates to form at least one inlet port and at least one outlet port; inverting one of the plurality of cells relative to the other, whereby the plurality of metal substrates are in a stacked arrangement with their cell chemistry layers overlying one another such that both of their plurality of first sides or both of their plurality of second sides face inwardly in spaced apart opposing relationship to define a common first fluid volume for one of fuel or oxidant therebetween to form the cell device; providing at least one additional cell device in the same manner as the first said cell device; and stacking a plurality of said cell devices to form a bank of cells; Including, at least one second fluid volume is defined between a pair of adjacent cells, the at least one second fluid volume being for the other of fuel or oxidant, adjacent first fluid volumes are in fluid communication with one another through a plurality of openings disposed through a respective plurality of the metal substrates, the openings being aligned in a stacking direction to form a plurality of internal passages within the bank; the method further comprising pressing at least one of the plurality of metal substrates around the port to form a molded port feature extending inwardly within the common first fluid volume and / or extending outwardly away from the common first fluid volume.

27. 27. The method of any one of claims 20 to 26, further comprising stamping at least one of the metal substrates to form a flanged perimeter feature before inverting the plurality of cells.

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