Metal supported battery cell

Abstract

A metal-supported planar cell arrangement (200) comprising at least one pair of cells (110a, 110b), each cell (110a, 110b) comprising a metal substrate (120a, 120b) having a first side and a second side and a porous region (124) providing fluid communication between the sides, a planar cell chemistry layer (111, 112, 113) comprising a fuel electrode, an electrolyte, and an air electrode layer, the fuel electrode, electrolyte, and air electrode layer being coated or deposited on and supported by the porous region (124) on the first side, the plurality of metal substrates (120) having their cell chemistry layers (111, 112, 113) arranged in a stack such that two first sides or two second sides face inwardly in a spaced, opposing relationship, the inwardly facing sides thereby defining a common first fluid volume (140) for one of fuel or oxidant.

Description

TECHNICAL FIELD

[0001] The present invention relates to an improved battery cell and a battery stack comprising a plurality of such battery cells, and methods of manufacturing the same. More particularly, the present invention relates to metal supported battery cells and battery stacks thereof, and still more particularly, to metal supported solid oxide fuel cell (MS-SOFC) cells and battery stacks thereof, and metal supported solid oxide electrolysis cell (MS-SOEC) cells and battery stacks thereof. BACKGROUND

[0002] Solid oxide fuel cell

[0003] Fuel cells use an electrochemical conversion process to generate electricity from the oxidation of a fuel. The fuel cell can be of a tubular or planar configuration. A solid oxide fuel cell (SOFC) is based on a solid oxide electrolyte that conducts negative oxygen ions from a cathode to an anode located on opposite sides of the electrolyte. To this end, a fuel or a reformed fuel is in contact with the anode (fuel electrode) and an oxidant (e.g., air or oxygen-rich fluid) is in contact with the cathode (air electrode).

[0004] When designing a SOFC stack, significant challenges are encountered in mechanical, electrical, and thermal design. For example, in a planar SOFC stack arrangement, the battery stack is typically arranged in a stacking direction from one end of the stack (e.g., from a base plate end) to the other end (e.g., to an end plate end). The performance of the fuel cell / fuel cell stack repeat layers is affected by temperature and other factors.

[0005] Metal supported solid oxide fuel cell

[0006] Conventional ceramic supported (e.g., anode supported) SOFCs are mechanically weak and prone to cracking. Metal supported SOFCs (MS-SOFCs) have recently been developed, which have active fuel cell assembly layers supported on a metal base plate. In these cells, the ceramic layers can be very thin, as they only perform the electrochemical function (i.e., they are not self-supporting). Such metal supported SOFC stacks are more robust, less costly, and also exhibit better thermal characteristics. They can also be manufactured using conventional metal welding techniques.

[0007] WO2015 / 136295 describes a metal-supported SOFC in which the electrochemically active layer (or active fuel cell assembly layer) comprises anode, electrolyte and cathode layers deposited on and supported by a metal support plate 120 (e.g. a foil), respectively. As shown in Figures la to lc, the fuel cell repeating unit 90 comprises three plates or planar assemblies - the metal support plate 120, the separator plate (or interconnect plate) 150 and the spacer plate 130 sandwiched between them. It also has fluid ports 188, 200 for oxidant or fuel. The three plates are stacked on top of each other and are welded (fused together) by the spacer plate 130 to form a single metal-supported solid oxide fuel cell unit 90 in which the intermediate fluid volume 140 is defined by the space provided in the spacer plate 130. The metal assemblies of the fuel cell stack repeating layer 90 are in electrical contact with each other, with electron flow between them primarily through the fused / welded paths, thereby avoiding surface-to-surface contact resistance losses.

[0008] In MS-SOFCs, the metal substrate can be a porous metal substrate formed from a powder metal precursor (e.g. by tape casting), or more preferably, a metal support plate having a porous region in the form of a through-hole or small aperture, surrounded by a non-porous (solid) region. The porous region 124 is provided through the metal support plate 120 and an anode layer 113 (or cathode 111, depending on the polarity orientation of the electrochemically active layer 110) is coated on this region, with successive layers then coated on top, so that these layers are supported by the metal support plate 120. As shown, the electrolyte layer is typically coated on the face edges of the innermost electrode and extends to the metal substrate, thereby sealing gas within the porous region and the innermost electrode. The porous region allows fluid volume 140 (defined by the adjacent plates 120, 150 and spacer plate 130) to be in fluid communication with the electrochemically active layer 110 on the support plate 120 through the small aperture. As shown, the electrolyte layer is typically coated on the face edges of the innermost electrode and extends to the metal substrate (as an extended layer 123), thereby sealing gas within the porous region and the innermost electrode.

[0009] In the separator plate 150, up-and-down corrugations are provided to extend up to the cathode 111 (or anode 113, depending on the polarity orientation of the electrochemically active layer 110) of a subsequent fuel cell unit 90 stacked on top of this fuel cell unit, and down to the metal support plate 120 of its own fuel cell unit. This forms an electrical connection between the adjacent fuel cell units 90 of the stack, to serially connect the electrochemically active layers 110 (typically one on each fuel cell unit) of the stack to each other. Other pressed three-dimensional features, such as circular or elongated dimples (or troughs and peaks) extending from each face, are also suitable for providing electrical contact and structural support (against stack compression forces).

[0010] Further teachings relating to fuel cells, fuel cell stacks, fuel cell stack assemblies, and heat exchanger systems, arrangements 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, 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.

[0011] A solid oxide electrolysis cell (SOEC) can have the same structure as a SOFC but is essentially a solid oxide fuel cell operated in a regenerative mode, producing hydrogen and / or carbon monoxide and oxygen by using a solid oxide electrolyte to effect electrolysis of water and / or carbon dioxide. In a SOFC, fuel (e.g. hydrogen) is supplied to the cell from a fuel port and used by the cell, whereas in a SOEC, the cell produces, for example, hydrogen, which is collected at a fuel port.

[0012] The present invention is directed to a stack-repeating solid oxide cell unit suitable for use as a structure for a SOEC or SOFC. For convenience, in the following both SOEC or SOFC cell units will be referred to as "cell units" (i.e. denoting either a SOEC or SOFC cell unit).

[0013] There is a continuing need to improve the cost effectiveness of fuel cells, that is, to reduce the manufacturing cost of fuel cells would have a significant benefit in reducing the entry cost of fuel cell energy production. SUMMARY

[0014] According to an aspect, a metal-supported planar cell arrangement is described, comprising: at least one pair of cells, each cell comprising: a metal substrate having a first face and a second face and a porous region providing fluid communication between the faces; a planar cell chemistry layer comprising a fuel electrode, an electrolyte and an air electrode layer, the fuel electrode, electrolyte and air electrode layer being coated or deposited on and supported by the porous region of the first face; wherein: the plurality of metal substrates are arranged in a stack with their cell chemistry layers such that their two first faces or two second faces face inwardly in spaced, opposing relationship, the inwardly facing faces thereby defining a common first fluid volume for one of fuel or oxidant.

[0015] The present invention relates to a metal-supported planar cell arrangement, that is, a cell arrangement whose cell chemistry layers are planar (extend in only a single plane) and non-self-supporting, i.e. the cell chemistry layers are deposited as thin coatings or films on and (collectively) supported by porous metal substrates, respectively. This is in contrast to anode-supported, cathode-supported or electrolyte-supported cells, in which the cell chemistry layers form rigid, self-supporting sheet-like materials that exist independently and are mounted or connected to other support structures. The present invention relates in particular to metal-supported solid oxide fuel cells "MS-SOFCs" or solid oxide electrolysis cells "MS-SOECs".

[0016] The porous metal substrates support the cell chemistry layers only on their first faces; the second faces of each substrate do not support any cell chemistry layers, but rather the second faces face each other and are exposed to a common volume or space between them that enables the supply of a first fluid to the innermost electrodes on each first face (closest to the supporting metal substrate).

[0017] The (active) cell chemistry layers are planar, and thus, at least the part of the metal substrate that supports the chemistry layers is planar, too. The cell chemistry layers are laid out in the same order on each region, such that the metal substrates define a common first fluid volume that can serve as a fuel volume, with each cell having a fuel electrode closest to the supporting metal substrate, or as an oxidant volume, with each cell having an air electrode closest to the supporting metal substrate. In a stacked arrangement, the cell chemistry layers are located above and below each other (e.g. in parallel planes) and are typically laterally aligned with each other (i.e. flush with each other).

[0018] The two fuel electrodes can be electrically connected, and the two air electrodes of a pair of cells can be electrically connected. Typically, the innermost electrodes (closest to the supporting metal substrate) are electrically connected by an electrical connection between the two respective opposing metal substrates. The two outermost electrodes are connected by a connection between the two respective current collectors on the outermost electrodes.

[0019] The metal substrates can be sealingly connected together around their outer periphery.

[0020] Preferably, the plurality of metal substrates comprises two separate metal plates that are directly or indirectly connected together to form a stacked arrangement, e.g. such that each metal plate has a complete porous region (bounded by a non-porous region) and supports a cell chemistry layer coated on the porous region by itself. Typically, the two separate metal plates are identical.

[0021] In one embodiment, two metal plates are indirectly connected together to form a stacked arrangement, optionally with a (flat) metal spacer plate disposed between the two metal plates. The two metal plates and intermediate metal spacer plate can be sealingly connected together at least around their outer periphery, for example by welding through all three components.

[0022] When a spacer plate is provided between two separate metal plates, the disadvantage is that an additional component is required in the stack, but the advantage is that flat planar metal plates can be used, so that the battery chemistry layers can be laid directly on the planar metal plates by conventional coating or spraying deposition techniques. The spacer plate can comprise a frame or flat peripheral component sandwiched between the flat metal substrates (outside the active battery chemistry region), which creates a volume for the first fluid volume and sealingly surrounds the first fluid volume.

[0023] Typically, there should be no significant structures within the fluid volume that can impede flow, but if cell chemistry is provided that can support and / or contact the substrate (or chemistry), then additional spacer components can be provided in the form of open or very permeable structures.

[0024] As an alternative to indirect connection of the substrates, the two metal plates can be directly connected together so that they abut each other to form a stacked arrangement, one or both of the metal plates having an inherent shaped feature (e.g. a flanged peripheral feature) that forms the first fluid volume between the plates. The two metal plates can be directly sealingly connected together at least around their outer periphery, for example by welding. This reduces the number of components, as no spacer plate is required, thereby reducing material waste. It also conveniently allows electrical connection of the two metal plates.

[0025] As an alternative to separate substrates, the plurality of metal substrates are formed as a continuous metal substrate having a first face on which the battery chemistry layers are respectively coated or deposited on porous regions, the continuous metal substrate being folded (e.g. by 180 degrees) between the battery chemistry layers so that they overlie each other to form a pair of folded batteries, the pair of folded batteries defining a first fluid volume for one of fuel or oxidant. Conveniently, the innermost electrodes (i.e. closest to the supporting metal substrate) are electrically connected by means of the continuous metal substrate. Such a design also inherently requires fewer components and less welding / sealing.

[0026] The continuous metal substrate can be folded by 180 degrees, which can take the form of two 90 degree folds separated by a small section of continuous metal substrate, which in turn helps to define a common fluid volume enclosed by the continuous metal substrate. As described elsewhere, shaped features or spacer plates can be provided to support the substrates and maintain an open common fluid volume.

[0027] Preferably, the arrangement further comprises a plurality of pairs of folded cells stacked next to each other in a cell stack. In the cell stack, the innermost electrodes (closest to the supporting metal substrate) can be electrically connected by means of a continuous metal substrate, and the outermost electrodes can be electrically connected by means of a current collecting structure. The current collecting structure can be a permeable support structure, and only needs to be exposed to one fluid environment, which is the same fluid environment over its surface area. This reduces the thermal and chemical requirements of the current collecting structure.

[0028] Preferably, in the cell stack, each pair of folded cells is formed by an independent respective metal substrate, which is folded once to have only one folded end, a first fluid volume being provided within the folded substrate.

[0029] As an alternative (separate substrates), in the cell stack, adjacent pairs of folded cells are formed by the same continuous metal substrate, which is folded multiple times to have multiple opposite folded ends. Such a substrate can define multiple respective first fluid volumes for one of the fuel or oxidant. Such volumes can be replaced by respective second fluid volumes for the other of the fuel or oxidant.

[0030] Preferably, at least one metal substrate comprises a flange peripheral feature, and the metal substrates are sealed together around the flange peripheral feature to form a common first fluid volume therebetween. The flange peripheral feature can be formed by pressing the substrates into a concave configuration. Both metal substrates of the cell pair can comprise a flange peripheral feature.

[0031] Preferably, at least one fluid port, typically at least one inlet port and at least one outlet port, is provided as an opening through each metal substrate, the respective fluid ports being aligned with each other in the stacking direction, and in fluid communication with the common first fluid volume. Alternatively, at least one fluid port is in fluid communication with the common second fluid volume. Alternatively, at least a first fluid port is in fluid communication with the common first fluid volume and at least a second fluid port is in fluid communication with the common second fluid volume. The at least first fluid port and the at least second fluid port can convey a first fluid to the first fluid volume, a second fluid to the second fluid volume, respectively. At least a first exhaust port can be in communication with the common first fluid volume, and at least a second exhaust port can be in communication with the common second fluid volume. The at least first exhaust port and the at least second exhaust port can extract a first exhaust fluid from the first fluid volume, a second exhaust fluid from the second fluid volume.

[0032] Preferably, at least one metal substrate has a shaped port feature formed around its port, the shaped port feature extending inwardly in the common first fluid volume, elements of the shaped port feature being laterally spaced from one another to define a fluid path between elements of the port for enabling passage of fluid from the port to the common first fluid volume. Preferably, the shaped port feature is also formed by a method of pressing.

[0033] At least one metal substrate can have a shaped port feature formed around its port, the shaped port feature extending outwardly away from the common first fluid volume. In the case of multiple such cell pairs stacked adjacent to one another, such features can be used to laterally position a sealing gasket disposed between the cell pairs, or such features can contact an adjacent plate to form a hard stop to limit compression of the gasket between the cell pairs, or can form a surface upon which a seal can be formed in situ by a sealant or the like. Within a set of cells, the metal substrates can be electrically connected together, and such that the shaped port features can be conveniently welded to the shaped port features of an adjacent cell, thereby providing an electrical connection to both and enabling sealing of the port / manifold.

[0034] A support structure can be provided within the common first fluid volume to help maintain spacing between opposing respective inwardly facing surfaces, where compression forces for collecting current are less, or where the cells are sufficiently rigid.

[0035] The support structure can be a permeable support structure, and need only be exposed to one fluid environment, which is the same fluid environment over its surface area. This reduces thermal and chemical requirements of the support structure. The innermost electrode (closest to the support metal substrate) can be electrically connected by means of the metal substrate, and the outermost electrode can be electrically connected by means of a current collecting structure. The current collecting structure can be a permeable support structure, and need only be exposed to one fluid environment, which is the same fluid environment over its surface area. This reduces thermal and chemical requirements of the current collecting structure.

[0036] The support structure within the common first fluid volume can be equipped with a catalyst to facilitate, for example, internal reforming, for example when the common first fluid volume is a fuel volume. If a support structure is not provided within the common first fluid volume, such a catalyst can be provided on the metal substrate surface, for example when the common first fluid volume is a fuel volume.

[0037] Preferably, the inwardly facing surface defines a first fluid volume for fuel. The inwardly facing surface is typically the second surface of the metal substrate. In this arrangement, the cell chemistry layers face outwardly, and current can be conveniently collected from the outermost electrode.

[0038] Typically, the fuel electrode layer will be the first layer of cell chemistry deposited on the first face of the metal substrate. In case the inward facing face defines a first fluid volume for fuel (when operated as a SOFC), the inward facing face is thus the second face of the metal substrate, and fuel gas will pass from the second face through the porous region to the first face in order to contact the fuel electrode layer.

[0039] In an alternative cell arrangement, the inward facing face defines a first fluid volume for oxidant. In this case, if the fuel electrode layer is again the first layer of cell chemistry deposited on the first face of the metal substrate, the inward facing face is thus the first face, so that the cell chemistry is within a common first fluid volume, and the air electrode layer will be exposed to the first fluid volume for oxidant. In said arrangement, the outermost electrode is positioned within the substrate, so it is necessary to take care of the insulation of any current collecting means from the substrate itself (at opposite electrical potential).

[0040] Preferably, pairs of cells are stacked adjacent to each other to form a group of cells, whereby at least one second fluid volume is defined between adjacent pairs of cells, and the first fluid volume is for one of fuel or oxidant, and the at least one second fluid volume is for the other of fuel or oxidant. This means that alternating first and second fluid volumes are defined along the stacking direction. Thus, the other respective faces of the metal substrate of the respective pair of cells of the group that face outwardly are in spaced apart opposing relationship with the corresponding faces in the adjacent respective pair of cells. Typically, the first fluid volume is defined between the metal substrates of a pair of cells, and the second fluid volume is defined between adjacent pairs of cells.

[0041] In the group, adjacent first fluid volumes can be in fluid communication with each other through openings provided by the respective metal substrates, which are aligned in the stacking direction to form internal passages (manifolds) within the cell group. This can equally apply to the second fluid volumes. However, one of the two fluid volumes can have inlet and / or outlet ports of external manifold type. The internal passages can be sealingly defined by spacers located between the pairs of cells in the group.

[0042] A support structure can be present within the common first fluid volume, and can be equipped with catalysts in order to facilitate, for example, internal reforming. If a support structure is not provided within the common first fluid volume, such catalysts can be provided on the surface of the metal substrate, for example when the common second fluid volume is a fuel volume.

[0043] Preferably, all fuel electrodes in the group are electrically connected, and / or all air electrodes in the group are electrically connected. This means that the electrodes of one type are connected in parallel. This results in a relative increase of the current output of the group.

[0044] In a highly preferred arrangement, all of the respective cell pairs in a group are welded together, thus all of the substrates are electrically connected. The welding can be done during the stacking process as each cell is added to the stack.

[0045] Preferably, the metal substrates and cell chemistry layers are arranged by face edges, and the connected fuel electrodes and / or air electrodes are connected along the same face edges.

[0046] Preferably, the fuel electrodes in a group are connected in series to the air electrodes of the next adjacent group. This results in a relative increase in the voltage output of the fuel cell group.

[0047] Preferably, an insulating plate is provided between adjacent groups to prevent direct electrical contact between adjacent groups (e.g., the outermost electrodes of adjacent groups). For example, when individual groups are connected in series, the last substrate of one group can be electrically connected to the outermost electrode of an adjacent group.

[0048] In one embodiment, a single cell is provided at the end of a group, and the cell is in direct electrical contact with an adjacent group (e.g., between the substrate of the single cell and the outermost electrode of the adjacent group) in order to connect the adjacent groups in series.

[0049] Such single or unpaired cells can include a metal substrate with an active cell chemistry layer on top, attached to a non-porous metal plate to form an end block (e.g., by welding to form an end block with a closed fluid volume). The metal plate can be, for example, a non-drilled metal substrate, which can also be flat and unshaped. Advantageously, in this way, adjacent groups can be connected in series, and face-to-face contact over most of the cell area, without the need for additional electrical connections. For example, a group can have all of its interconnects connected in parallel, and the outermost interconnect can contact (physically and electrically) the non-porous metal plate of the end block of an adjacent group, and be connected in series therewith. In that adjacent group, the non-porous metal plate and substrate are at the same potential, and are connected in parallel with all other metal substrates in that group. Thus, the parallel substrates in the adjacent group are connected to the parallel connected interconnects in the first group by a series connection.

[0050] According to another aspect, there is described a method of assembling a metal supported planar cell arrangement, the method comprising: providing a first cell and a second cell, each cell comprising: a metal substrate having a first face and a second face and a porous region providing fluid communication between the faces; a planar cell chemistry layer comprising a fuel electrode, an electrolyte and an air electrode layer, the fuel electrode, electrolyte and air electrode layer being coated or deposited on the porous region of the first face and supported by the porous region on the first face; and inverting one cell relative to the other cell to stack their cell chemistry layers with their two first faces or two second faces facing inwardly in spaced, opposing relationship to define a common first fluid volume therebetween for one of fuel or oxidant to form a cell arrangement.

[0051] The method can comprise electrically connecting the two fuel electrodes or two air electrodes in the pair of cell units. In a continuous substrate, such a substrate can provide the connection.

[0052] Thus, a repeating unit comprising a pair of cell units defining a common first fluid volume therebetween can be manufactured.

[0053] Preferably, the metal substrate is formed as a continuous metal substrate and the inverting comprises folding the continuous metal substrate between the cell chemistry layers so that they overlie one another to form a pair of folded cells defining the first fluid volume for one of fuel or oxidant. The folding can be to 180 degrees and can comprise two 90 degree folds separated by a spacing corresponding to a desired height of the first fluid volume.

[0054] Preferably, the cell chemistry layers of the pair of cells are coated or deposited on the porous region of the first face respectively and the metal substrate is subsequently folded. Conveniently, the subsequent folding of the coating or deposition means that the substrate does not need to be flipped over to coat or deposit the cell chemistry layers of the pair of cells and means that the cell chemistry layers of the pair of cells can be coated or deposited in the same manufacturing process.

[0055] Preferably, a pre-fold is created on the metal substrate prior to coating or depositing the cell chemistry layers. The pre-fold is a precursor to the fold positioned in the intended location of the fold or folds and the cell chemistry layers of the pair of cells are subsequently coated or deposited to either face of the pre-fold. The pre-fold can be created by stamping or scoring a continuous or discontinuous line across the metal substrate. If the fold comprises two 90 degree folds, then two pre-fold lines are created. More pre-fold lines can be created as precursors to multiple folds of the substrate. The pre-fold creates a line of weakness along which the substrate is more easily folded in the folding step after the coating or depositing of the cell chemistry layers, which reduces the likelihood of damaging the cell chemistry layers in the process of folding the substrate. That is, the pre-fold creates a line of weakness.

[0056] The planarization step can be after the step of creating the pre-folds. The planarization ensures that the substrate is sufficiently planar for the application or deposition of the battery chemistry layers.

[0057] Preferably, the assembly method further comprises cutting an opening through each metal substrate to form at least one inlet port and at least one outlet port.

[0058] Thus, ports for fluid transfer are formed in each metal substrate. On folding and / or stacking of the metal substrates, the respective fluid ports align with each other in the direction of the folding and / or stacking and communicate with a common first fluid volume. Other ports can similarly communicate with a second fluid volume.

[0059] Preferably, at least one metal substrate is pressed around its ports to form a shaped port feature that extends inwardly within the common first fluid volume or outwardly away from the common first fluid volume.

[0060] In a subsequent step, the metal substrates can be sealed together around some or all of their periphery (e.g. around one, two, three or all four faces) by a flange peripheral or a separate spacer assembly. In the case of folded continuous substrates, the folded faces can or can not require a flange peripheral. A subsequent step of welding or brazing around the flange can be used. This step of welding or brazing around the periphery seals the first fluid volume from the remaining environment, which can or can not communicate with the second fluid volume.

[0061] The pressing step(s) provide(s) a recess for the first and / or second fluid volumes. The flange around the periphery and the shaped port feature extending inwardly within the common first fluid volume can be formed in the same or separate pressing steps. The steps of pressing and cutting can be performed before or after the application or deposition of the battery chemistry layers; preferably, the steps of pressing and cutting can be performed before the application or deposition of the battery chemistry layers to prevent damage to the battery chemistry layers.

[0062] Preferably, further battery arrangements are provided in the same manner as the first battery arrangement, the battery arrangements are stacked into groups, and an electrical connection is provided between the fuel electrodes within a group and / or the air electrodes within a group. A further step can comprise stacking respective battery groups to form a battery stack. An insulator can be provided between adjacent battery groups so that respective end cells in adjacent groups are not connected in series. Alternatively, adjacent groups can be connected in series, with a single cell provided at the end of a battery group.

[0063] Preferably, the metal substrates are substantially rectangular, and port holes are provided at their left and right ends, with the battery chemistry layers in the central region facing outwards from each pair of metal substrates, and electrically and fluidically conductive spacer plates laid over the outermost chemistry layers (outermost electrodes), contacting the chemistry layers and separated from the metal substrates so as to provide electrical contact to the chemistry layers of another battery placed above and below in a stacked arrangement, and the spacer plates are provided with electrical connections at their front and / or rear edges perpendicular to the arrangement of the port holes. Preferably, the electrically conductive spacer plates are separated from the underlying metal substrates by an extended region of electrolyte that surrounds the central region and acts as an insulator. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure la shows an exploded view of a prior art solid oxide fuel cell unit;

[0065] Figure lb shows a cross-sectional view of a prior art fuel cell unit, inverted relative to Figure la;

[0066] Figure lc shows a cross-sectional view in two prior art fuel cell units in a stacked arrangement;

[0067] Figure 2 A novel arrangement of a pair of cell units in a back-to-back arrangement is shown, with active battery chemistry layers facing outwards;

[0068] Figure 3 Another alternative novel arrangement of a pair of cell units in a face-to-face arrangement is shown, with active battery chemistry layers facing inwards;

[0069] Figure 4a A set of fuel cell units is shown, comprising two pairs of cell units, each pair of cell units according to the back-to-back arrangement of Figure 2 ;

[0070] Figure 4b An alternative set of cell units is shown, with an alternative spacer arrangement;

[0071] Figure 5 A novel stacked arrangement is shown, in which a pair of sets of cell units (each set according to the back-to-back arrangement of Figure 4a ) are stacked on top of each other, with an insulating layer between adjacent sets of cell units.

[0072] Figure 6 The stacked arrangement of Figure 5 is shown, comprising a series electrical connection between the sets.

[0073] Figure 7a An alternative stacked arrangement is shown, in which there are three pairs of cell units in each set of cells, and two sets of cell units are stacked on top of each other, with an insulating layer between adjacent sets of cell units, and a series electrical connection between the sets of cell units.

[0074] Figure 7b An alternative arrangement of electrical connections between battery cell groups is shown.

[0075] Figure 7c Another alternative arrangement of electrical connections between battery cell groups is shown.

[0076] Figure 8a A novel battery cell comprising a metal substrate and active battery chemistry layers is shown;

[0077] Figure 8b Two such battery cells are shown arranged back-to-back with the active battery chemistry layers facing outward; and Figure 8c A group of battery cells is shown comprising two pairs of battery cells, each pair of battery cells being arranged according to Figure 8b Arranged back to back.

[0078] Figure 9a shows a novel battery cell including molded port features; Figure 9b Two such battery cells are shown arranged back-to-back with the active battery chemistry layers facing outward; and Figure 9c A group of battery cells is shown comprising two pairs of battery cells, each pair of battery cells being arranged according to Figure 9b Arranged back to back.

[0079] Figure 10a Another novel battery cell including a molded port feature is shown; Figure 10b Two such cells are shown arranged back-to-back with the active battery chemistry layers facing outward; Figure 10c A group of fuel cell units is shown, comprising two pairs of battery cells, each pair of battery cells being arranged according to Figure 10b Back-to-back arrangement; Figure 10d A battery arrangement is shown comprising two groups of battery cells, each group of battery cells comprising Figure 10c two pairs of battery cells; and Figure 10e A battery arrangement is shown comprising two groups of battery cells, wherein one group of battery cells has a single battery cell at the end of the group.

[0080] Figure 11 A first side of a battery cell is shown in a top perspective view.

[0081] Figure 12a Shows a pair of Figure 11 a battery cell, wherein the corresponding metal support substrates are welded together around the periphery of the flange; and Figure 12b Shown according to Figure 12a Cross-section of the cell from the periphery of the flange of the base plate through the flue.

[0082] Figure 13 A pair of battery cells according to Figure 12 is shown, with an air-side conductive support structure located above the battery cells.

[0083] Figure 14a A pair of battery cells and conductive support structure according to Figure 13 of Figure 12, with a third battery cell added on top; and Figure 14b A pair of battery cells according to Figure 14a A cross-sectional view of a battery cell passing through a flue from the flanged outer periphery of the substrate.

[0084] Figure 15a A stack of battery cells and conductive support structure is shown; Figure 15b A pair of battery cells according to Figure 15a A cross-sectional view of a group of battery cells passing through a flue from the flanged outer periphery of the substrate. Figure 15c A stack arrangement of a pair of groups of battery cells is shown, where each group of battery cells is according to Figure 15a a group of battery cells according to Figure 12, the pair of groups of battery cells stacked on top of each other, with an insulating layer between adjacent groups;

[0085] Figure 16a An alternative novel arrangement of a pair of batteries is shown, arranged in back-to-back form, where the active battery chemistry layers supported by a single folded substrate face outwards; Figure 16b A group of battery cells is shown, comprising two pairs of battery cells, each pair of battery cells arranged in back-to-back form according to Figure 16a Figure 12; and Figure 16c A battery cell according to Figure 16a is shown, comprising a shaped port feature.

[0086] Figure 17a An alternative novel battery cell is shown, comprising an arrangement of two pairs of fuel cells, each pair arranged in back-to-back form with the active battery chemistry layers facing outwards, where the two pairs of batteries are supported by a single folded substrate; Figure 17b A battery cell according to Figure 17a is shown, comprising a shaped port feature. DETAILED DESCRIPTION

[0087] A list of reference signs used in the detailed description is given at the end of the detailed description. Repeated use of reference signs in the present specification and drawings is intended to represent the same or similar features or elements in the description unless context dictates otherwise.

[0088] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the scope of the present application. For instance, features described as part of one embodiment can be used in another embodiment to create yet another embodiment. Thus, it is intended that the present application cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

[0089] In the following description, air is used as the oxidant. Thus, any reference to "oxidant" anywhere in the text can be understood as a reference to "air", and vice versa.

[0090] Reference is made to Figure 2 , which shows an arrangement 200 of a pair of battery cells arranged in a back-to-back fashion. The pair of battery cells 200 has a first battery cell 110a supported by a first metal support plate 120a, and a second battery cell 110b supported by a second metal support plate 120b. Each metal-supported battery cell 110a, 110b comprises battery chemistry layers 111, 112, 113 deposited or coated on a metal substrate 120 to form an electrochemically active layer 110. An anode layer 113, an electrolyte layer 112, and a cathode layer 111 are laid down in that order on a porous region 124. However, in some battery arrangements, the order can be reversed (so that the cathode layer is closest to the substrate).

[0091] As in Figure 1, the metal substrate 120 is a metal foil, typically ferritic stainless steel. The porous region 124 comprises a series of through-holes formed by drilling (or other means, such as etching) that extend from a first face 125 of the metal substrate 120 to an opposite face (second face 126) of the metal substrate 120, surrounded by a non-porous (solid) region.

[0092] The anode layer 113, electrolyte layer 112, and cathode layer 111 can be formed by deposition onto a planar metal substrate 120, for example, chemical vapor deposition, electrostatic deposition, spray deposition, spin-coat deposition, powder deposition, and the like. The process can be a two-step process, first depositing a powder or granular material, followed by sintering or other treatment to form each layer of the solid oxide battery. Each layer is a thin layer, so none of the layers are self-supporting; that is, the metal substrate is required to support the solid oxide chemistry layers. Other barrier layers can also be provided, for example, an extended electrolyte layer 123. As with prior art batteries, the electrolyte layer is coated on the face edges of the innermost electrodes, and extends over the metal substrate, sealing the gases within the porous region and the innermost electrodes.

[0093] In Figure 2Each metal substrate 120a, 120b has a first face 125 and a second face 126, with the porous region 124 extending between the faces thereof. The porous region 124 allows fluid on the second face 126 of the metal substrate 120 to reach one face of the electrochemically active layer 110 (the anode layer, as shown). The electrochemically active layer 110 (including the anode layer 113, electrolyte layer 112, and cathode layer 111) is supported by the porous region 124. The second faces 126 of the two metal substrates 120a, 120b are attached to opposite faces of one or more spacer plates 130, such that the cell has similar faces in a back-to-back arrangement. This arrangement forms a first fluid volume 140 between the pair of metal substrates 120a, 120b. A support structure 131 can be provided between the pair of metal substrates to account for the compressive load required, if any, and to serve to collect current from the outermost electrodes (see Figure 4a The anode layers 113 of the two cells thus face each other through the first fluid volume 140. With the anode layers 113 (or fuel electrodes) of the two cells facing each other through the first fluid volume 140, the pair of metal substrates will enclose the fuel volume, and the support structure 131 will be exposed to fuel only. In this case, the support structure can provide an ancillary function, namely, to support the catalyst required for internal reforming of the fuel. The volume needs to be sealed so that fuel gas cannot contact oxidant gas.

[0094] As explained below, fuel (e.g., hydrogen or hydrocarbon gas) needs to access the fuel electrode or anode (in SOFCs) face of the cell, and oxidant (e.g., air or oxygen) needs to access the air electrode or cathode face of the cell. 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 used for fuel. However, in a back-to-back arrangement, if the cathode layer 111 is deposited first instead, then the first fluid volume would need to be an oxidant fluid volume.

[0095] The support structure 131 can be similar to the interconnect 160 of Figure 1b or the interconnect 150a of Figure 1c, but in this case need not extend all the way to the spacer plate 130. Also, Figure 2 The support structure 131 is exposed to only one environment (fuel or oxidant) and need not separate the two environments. Thus, the chemical, thermal, and mechanical demands on the support structure are lower than for prior art designs. Also, the support structure 131 should be sufficiently open to allow fluid to pass from one face of the support structure 131 to the other.

[0096] The support structure 131 need not be electrically conductive, although it can be. This is because the spacer plate 130 (used to separate two metal substrates in an arrangement of pairs of battery cells) can be electrically conductive, thus enabling electrical connection between the two metal substrates. The electrical connection through the spacer plate 130 can be aided by a weld or solder of the metal substrates and the spacer plate. This weld or solder also seals the first and second fluid volumes. Furthermore, because the electrical interconnection between the batteries does not rely on an electrical connection between the support structure 131 and the metal substrates 120, the compressive load through the support structure (and the strength of the support structure) can be reduced compared to the interconnection 150 of Figure 1. The support structure 131 is schematically illustrated as a corrugated element, but other pressed three-dimensional features, mesh structures, or expanded metals can be used.

[0097] For clarity, Figure 2 (and subsequent Figure 3 A port is not shown in Figure 7 provided in the metal substrate 120 that allows fluid (typically fuel) to be delivered to the first fluid volume 140. The port through the metal substrate 120 can be sealed by a gasket or weld between the metal substrate and the spacer plate 130. The port and the spacer plate (or a shaped feature around the port) collectively form a flue for the first fluid to be delivered in the stack. The port feature or manifold allows a portion of the fluid to exit the flue and enter the first fluid volume 140. One or more flues are used to provide exhaust gas to exit from the first fluid volume 140.

[0098] Figure 3An alternative face-to-face arrangement of a pair of battery cells 300 is shown. The 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 of the pair of electrochemically active layers 110a, 110b has a battery chemistry layer including a cathode layer 111, an electrolyte layer 112, and an anode layer 113, as described above. Each metal substrate 120a, 120b includes a first face 125 and a second face 126, with a porous region 124 extending between the faces and supporting the electrochemically active layers 110a, 110b. The first face 125 of the metal substrates 120a, 120b is attached to opposite faces of one or more spacer plates 130, such that the electrochemically active layers 110a, 110b face each other inwardly, arranged in a face-to-face format. This arrangement forms a first fluid volume 141 between the pair of metal substrates 120a, 120b. An electrically conductive support structure 310 can be provided between the pair of metal substrates. That is, the cathode layers 111 of the two battery cells face each other through the first fluid volume 141, so as to form the first fluid volume 141. In this case, the first fluid volume 141 is typically an oxidant (air or oxygen) volume. The electrically conductive support structure 310 is similar to the support structure 131, except that the electrically conductive support structure 310 serves as a current collector to conduct current from the (outermost) electrode layer (in this case, the cathode layer 111) away from the metal substrate 120.

[0099] The support structures 131 and the electrically conductive support structures 310 are schematically illustrated as corrugated elements, but other pressed three-dimensional features can equally be used. They can serve to provide electrical connections between adjacent battery cells. In this way, the support structures and the electrically conductive support structures serve to resist bending or warping of either side metal substrate. The support structures 131 and the electrically conductive support structures 310 preferably have gaps (not visible in the illustrated cross-sectional faces) for free circulation of fluid therethrough, both in the figure from left to right (or right to left, or front to back, or back to front) and in the figure from top to bottom (or bottom to top, or towards and away from the metal substrate), i.e. they are permeable.

[0100] Figure 4a A battery cell group 400 is shown including two pairs of solid oxide batteries 200a, 200b, each pair of batteries according to Figure 2Any of the descriptions in . (Each set includes a first pair of electrochemically active layers 110a, 110b and a second pair of electrochemically active layers 110c, 110d). The two pairs (or more) of battery cells are stacked on top of each other with one or more spacers 180a, 180b in between. The spacers 180a, 180b connect the first fluid volume of adjacent pairs of cells 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 can be similar to the conductive support structure 310 described previously. The current collector can be provided as a pressureless current collector.

[0101] Figure 4b A battery cell set similar to Figure 4a is shown, but the support structure 131 is shown as a short spacer placed inside the first fluid volume 140a, 140b. The support structure 131 is electrically conductive in order to electrically connect the respective metal substrate on either side (but does not have to be, this functionality can be provided at the edge as will be described below). The support structure 131 can be a separate component from the metal substrate 120 or can be formed by a pressed or formed feature of the metal substrate, as long as it is outside of the battery chemistry layers. The support structure 131 can also serve to prevent warping or bending of the metal substrate 120 due to the compression forces required for current collection.

[0102] In Figure 4b , a general spacer layer 440 is shown in place of the conductive support structure 310. The spacer layer 440 includes a mesh, expanded metal, or a combination thereof. The spacer layer 440 is located inside the second fluid volume 430 to provide interconnection between the second battery cell 110b of the first pair of battery cells 200a and the first battery cell 110c of the second pair of battery cells 200b. The layer 440 has spaces or voids for circulation of oxidizer (or fuel, as the case can be).

[0103] Figure 5 A battery cell stack 500 is shown that includes two or more sets 400a, 400b of battery cells 200a, 200b stacked on top of each other. Each set 400a, 400b is similar to the set 400 in Figure 4a or Figure 4b . The stack also includes an insulating layer 510 placed between each pair of sets 400a, 400b to electrically insulate the sets from each other. A conductive support structure 530 is provided to contact the electrochemically active layers 110 to act as a current collector (for the cathode layers in the case where the first fluid volume is a fuel volume (e.g., hydrogen for SOFCs) and the second fluid volume is an oxidizer volume). Additional sets can be added to the stack by repeating the conductive support structure 530 and the insulating layer 510.

[0104] Figure 5Two pairs of battery cells are shown in each group 400a, 400b. However, one pair of battery cells or more than two pairs of battery cells can also be used. See Table 1 (below).

[0105] Figure 6 A stack 600 of two groups of battery cells is shown, similar to Figure 4a , Figure 4b and Figure 5 stacks. (There can be more such groups, but only two are shown). Busbars 610, 615, 620 are provided, busbar 610 is connected to the conductive separator plates 130 between each pair of battery cells of the first group 400a (and thus to their metal substrates). Thus, generally busbar 610 electrically connects the anodes in the first group. Busbar 615 is connected to the conductive support structures 630 between the electrochemically active layers 120 of the second group 400b. Thus, generally busbar 615 electrically connects the cathodes in the second group. Busbar 620 connects the conductive support structures 630 of the first group 400a to the conductive separator plates 130 of the second group. Thus, generally busbar 620 electrically connects the cathodes in the first group and the anodes in the second group. The busbars are preferably welded to their respective separator plates 130 and conductive support structures 630. The separator plates 130 are shown as extending outward to touch the busbars 610, 620, or, the metal substrates 120 can extend to touch and electrically connect to the busbars 610, 620. Busbars 610 and 615 can connect to other battery cells of adjacent groups (not shown), thus having a similar arrangement as busbar 620. Alternatively, busbars 610, 615 can not connect to the battery cells of adjacent groups, but instead can connect to a power output to deliver power out of the stack for external use.

[0106] In this way, a parallel-series arrangement of battery cells is provided. All of the anodes of a particular group are connected in parallel. Similarly, all of the cathodes of a particular group are connected in parallel. This helps to meet the current requirements imposed on the stack of battery cells. The battery cells of one group are connected in series with the battery cells of an adjacent group. The cathodes of one group (e.g., first group 400a) are connected in series with the anodes of an adjacent group (e.g., second group 400b). This helps to meet the voltage requirements imposed on the stack. More groups can be added to further increase the voltage.

[0107] Figure 7a A stack 700 of two groups 710a, 710b of battery cells is shown more schematically. The stack includes multiple groups of battery cells stacked on top of one another, with an insulating layer 510 placed between each pair of groups 710a, 710b of battery cells. Additional groups can be added to the stack 700 by repeating the insulating layer 510 and groups 710.

[0108] Each group includes multiple pairs of battery cells. In the example of the figure, each group has three pairs of battery cells. However, one, two, or more than three pairs of battery cells can also be used. See Table 1 (below).

[0109] Figure 7a For Figure 6 simplification, the electrical connections of the battery cells between groups are shown. Also, all anodes of a particular group are connected in parallel. Similarly, all cathodes of a particular group are connected in parallel. This helps to meet the current requirements imposed on the stack of battery cells. The battery cells of one group of battery cells are connected in series with the battery cells of an adjacent group. The cathodes of one group (e.g., first group 710a) are connected in series with the anodes of an adjacent group (e.g., second group 710b). This helps to meet the voltage requirements imposed on the stack.

[0110] Figure 7b A stack of two groups of battery cells is shown, similar to the groups described with reference to Figure 6 and Figure 7a The stack also includes electrically conductive gaskets 730a and 730b, which are provided between the metal substrates of adjacent pairs of battery cells to transport fuel between the pairs of battery cells. The electrically conductive gaskets 730 serve the role of the busbar 610, which electrically connects the anodes of a group of battery cells in Figure 6 Then, the busbar 720 is used to connect the cathodes in the first group with the anodes in the second group. Typically, the busbar 715 electrically connects the cathodes in the second group, and can be connected to the anodes in another group (not shown).

[0111] Figure 7b A stack of two groups of battery cells is shown, similar to the groups described with reference to

[0112] Figure 7c A stack of two groups of battery cells is shown, similar to the groups described with reference to Figure 7b and also includes solid blocks 731 placed between the electrically conductive support structures 630 between each pair of battery cells. The solid blocks 731 electrically connect the first and second groups of battery cells, as previously described, and eliminate the need for busbars and welding the busbars to the stack of battery cells.

[0113]

[0114]

[0115] Table 1

[0116] Table 1 shows that when the cells are operated as MS-SOFC cells, the volumetric power density increases as the number of cells in a group increases relative to the prior art design of FIG. When operating in S-SOFC mode, with a group having only two cells (i.e., a pair of cells arranged back-to-back or face-to-face), the volumetric power density increases by 19%. This is because one fluid volume is now shared by two electrochemically active layers on two metal substrates 120. Consequently, 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, as the amount of viscous losses due to frictional effects at the fluid volume walls is reduced.

[0117] Those skilled in the art will appreciate that these advantages also apply when the battery cell operates as an MS-SOEC cell.

[0118] For battery cell groups with four cells (i.e., two pairs of cells arranged back-to-back or face-to-face), the increase in volumetric power density is somewhat greater. This is because for a given number of cells in the stack, fewer separators are required between the groups (which increases the stack height).

[0119] The gain in volumetric power density is less pronounced when increasing from two to three (and four, etc.) pairs of cells per group. Furthermore, as the number of cells per group increases, the current produced by each group also increases. This can be advantageous in high-current applications, but it results in greater resistive losses and may require components to be formed from thicker or more conductive materials to withstand or mitigate resistive heating.

[0120] The metal substrate can be completely flat so that its entirety lies on a single plane, or, as described below, beyond the battery chemistry layers, the substrate can be pressed or formed so as to have 3D features that can be created before or after depositing the battery chemistry layers.

[0121] Variants of unspaced plate-type battery cell pairs

[0122] The following embodiments of FIGS. 8-10 show pairs of battery cells according to the present application in which the battery cells are directly connected together so that they abut one another, and these pairs of battery cells can be referred to as spacerless pairs of battery cells. To achieve the required common fluid volume between the battery cells, each metal substrate is not flat, but has a shaped (e.g., pressed or stamped) 3D feature that eliminates the need for a spacer to create the fluid volume between the battery cells. These examples are shown in a back-to-back arrangement for illustration. The spacerless pairs of battery cells of FIGS. 8-10 are not drawn to scale, but there are discontinuities in the active battery chemistry (not fully shown) so that the ends where the ports are located can be shown in more detail. The actual ports through the metal substrate 120 are not shown for clarity.

[0123] Figure 8a A battery cell 810 is shown that includes an electrochemically active layer 110 deposited or coated on a metal substrate 120. (In the figures, the active layer and substrate are truncated at the center in order to focus on the edges.) A thin electrochemically active layer 110 is again laid over a supporting metal substrate 120 as previously described. The second face 126 of the metal substrate 120 has shaped (e.g., pressed or stamped) features or protrusions 840 that extend out of (as shown, down from) its surface. The protrusions 840 are illustrated as triangular (i.e., a cone or pyramid in three dimensions), but can have other cross-sectional shapes, such as a dome or a bump, and can have a peak. The protrusions 840 are distributed around the ports (not shown) to allow fluid to flow from the ports to the first fluid volume or from the first fluid volume to the ports (i.e., fluid is transported between the ports and the fluid volume). In this way, the protrusions pass the stack compression load around the ports while maintaining the required fluid passage from the fluid chimney opening to the first fluid volume.

[0124] The apex or peak of the protrusions (or features formed in the substrate) 840 extends away from the second face 126. The metal substrate 120 also includes shaped features, including flanges 850 at its periphery. The flanges are positioned in a plane that is parallel to and vertically spaced apart from the main plane of the metal substrate 120 (lower in the orientation shown in the figure). The main 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 ways of forming a planar metal substrate. The porous region and electrochemically active layer 110 can be formed before or after the protrusions 840 and flanges 850 are formed, but preferably the protrusions 840 and flanges 850 are formed before the electrochemically active layer 110 is deposited to reduce the chance of damage to the layer.

[0125] Figure 8bA pair of unspaced plate-type battery cells 805 are shown in a back-to-back arrangement, with each battery cell 810a, 810b as shown in FIG. Figure 8a As shown, the battery cell pair includes a first battery cell and a second battery cell. The first battery cell 810a and the second battery cell 810b are connected back to back, wherein the peak of the protrusion 840a extending from the first battery cell touches or abuts the protrusion 840 extending from the second battery cell. The battery cell pair 805 forms a continuous fluid volume 140 between the first metal substrate and the second metal substrate. The volume is sealed around the peripheral flange 850 by welding, brazing or similar techniques. As shown in FIG. Figure 8b As will be apparent, the protrusion 840 and flange 850 eliminate the need for a spacer plate (eg, spacer plate 130 of FIG. 4 ) between the battery cells 810a, 810b in the battery cell pair 805 arranged in a back-to-back arrangement.

[0126] Figure 8c A battery cell group 870 is shown that includes two pairs of unspaced plate-type battery cells, each pair of battery cells 805a, 805b as shown in FIG. Figure 8b As previously described, there may be one or more than two pairs of battery cells in each group. The pairs of battery cells 805a, 805b are positioned in a stacked arrangement: stacked on top of each other, with one or more gaskets 180 providing a fluid connection between adjacent pairs of first fluid volumes as previously described. As previously described, these gaskets may be electrically conductive and electrically connected to the substrates of adjacent battery pairs. A conductive support structure 440 is provided between adjacent pairs of battery cells to electrically connect the surfaces of the electrochemically active layer away from the metal substrate 120 (e.g., to connect the cathodes (outermost electrodes) of the first pair of battery cells 805a with the cathodes of the second pair of battery cells 805b). The conductive support structure 440 is similar to the conductive support structure 440 described previously and may include a mesh, expanded metal, or may be similar to the conductive support structure 310. Optionally, a support structure 131 may be provided within the fluid volume 140, as previously described.

[0127] Figures 9a to 9c Shown Figures 8a to 8c Variations of battery cells. Figure 9aThe battery cell is provided with a raised port feature 910 around the fluid port 980. Preferably, the raised port feature is annular. The raised port feature includes a planar surface parallel to and vertically spaced apart from the major plane of the metal substrate 120 (higher in the orientation shown in the figure). The planar surface 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 layers, each of which is planar and vertically spaced apart: the planar surface of the raised port feature 910 is on the major plane of the metal substrate, while the major plane of the metal substrate itself is on the plane of the flange 850. The raised port feature 910 is formed in the metal substrate 120 by pressing, stamping, or forming the planar metal substrate, similar to and preferably simultaneous with the protrusion 840 and the flange 850. The protrusion 840 and the raised port feature 910 are arranged to transfer stack compression loads around the port while maintaining the required fluid passage from the fluid chimney opening to the first fluid volume 140.

[0128] Figure 9b A pair of battery cells 905 as described in Figure 9a The first and second battery cells are arranged back-to-back, with the peak of the protrusion 840 extending from the second face of the first battery cell touching or abutting the protrusion 840 extending from the second face of the second battery cell. The pair of battery cells enclose the first fluid volume 140 between the first and second metal support plates. The height of the first fluid volume 140 is defined by the protrusion 840 and the flange 850, and sealed by the weld around the perimeter of the flange 850.

[0129] Figure 9c A battery cell group 900 is shown including two pairs of battery cells, each pair of battery cells 905a, 905b as described in Figure 9a As described previously, there can be one or more than two pairs of battery cells in each group, and multiple groups can be stacked and electrically connected as described previously. The pairs of battery cells 805a, 805b are positioned in a stacked arrangement: stacked on top of each other, with the stacked arrangement between adjacent pairs of battery cells forming a second fluid volume 430.

[0130] The raised port features 910 of adjacent pairs of battery cells are spaced apart from the adjacent pairs of battery cells and create the second fluid volume 430. The height of the raised port features is sufficient to create the second fluid volume, thus isolating the electrochemically active layers 110 of the battery cells in the first pair of battery cells from the electrochemically active layers 110 of the battery cells in the adjacent second pair of battery cells. The raised port features 910 and the ports 980 form a fluid chimney for conveying fluid to (or from) the first fluid volume 140.

[0131] The planar surface of the raised port feature of the first cell unit interfaces with the corresponding planar surface of the raised port feature of the second cell unit, which is an adjacent cell pair to 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 the gasket 180 described with reference to FIG. 4) between and spacing apart the adjacent cell pair to create a second fluid volume. These cell pairs can be referred to as gasketless, spacerless cell pairs, which can be formed into a stack with an even lower part count.

[0132] In order to seal the chimney, the interface between the planar surface of the raised port feature of the first cell unit and the corresponding planar surface of the raised port feature of the second cell unit must be sealed, and fluid mixing between the first and second fluid volumes prevented. The sealing can be performed using a gasket: a preformed gasket, or preferably, a sealing contact glue or liquid that forms a seal in situ. The latter can be provided in an annular groove in one or both interface planes. Additionally, a (e.g., compressible) annular gasket can be placed, if desired, also around the outside perimeter of the raised port feature, and secured. Or more advantageously, the sealing can be performed by welding a seal around the interface plane of the raised port feature, which further reduces the part count.

[0133] Figure 10a A variant of the cell unit of Figure 9a is shown. In contrast to the raised port feature 910 of FIG. 9, the raised port feature 1050 is moved radially outward from the circumference of the port 980. This causes the planar surface of the raised port feature 1050 to be supported on its radially inward and radially outward (relative to the port 980) faces by the protrusions 840, 1040. The raised port feature 1050 is an annular ring supported on two faces. An additional protrusion 1040 is shown in the figure, which is similar to the protrusion 840, except that it is disposed between the port 980 and the raised port feature 1050, whereas the protrusion 840 is disposed radially outward (relative to the port 980) of the raised port feature 1050. The raised port feature 1050 passes compression through the cell stack via the protrusions 840 and 1040. In this way, the raised port feature 1050 is arranged to pass the stack compression load required to surround the port with a gasket (see Figure 10d ) between the sealing groups, while maintaining the required fluid passage from the fluid chimney opening to the first fluid volume 140.

[0134] Figure 10b A pair of how such cell units are arranged back-to-back so that the additional protrusions 1040 abut against each other (in a similar manner to the protrusions 840) and provide spacing between the metal substrates to allow fluid to pass from the fluid chimney and the port 980 into the first fluid volume 140 is shown.

[0135] Protrusion 1040 is shown protruding into first fluid volume 140. Protrusion 1040 may protrude into and away from the volume in alternative manners. This will be described below. Where protrusion 1040 protrudes away from fluid volume 140, protrusion 1040 protrudes to the same level as raised port feature 1050 so as to share stack compression loads with raised port feature 1050. Protrusion 840 may be substituted in a similar manner.

[0136] Figure 10c A group of such cells is shown, illustrating how the raised port features 1050a in one pair of cells abut against the raised port features 1050b of an adjacent pair of cells. Figure 9c As described, the raised port feature has an interface and is sealed to define a flue.

[0137] Figure 10d Two groups of battery cell pairs are shown in a stacked arrangement. An insulating layer 1070 is provided between the battery cell groups, separating and electrically isolating adjacent planar surfaces of the raised port features 1050. The isolation layer 1070 (e.g., an electrolyte layer) can be similar to the insulating layer 510 (as previously described with respect to FIG. Figure 5 980) or may be in the form of an insulating glue. An additional gasket 1080 is provided inside the flue, located radially inward (relative to ports 980) of adjacent groups of opposing raised port features 1050a and 1050b and disposed above the protrusion 1040 to seal and transfer compressive forces across the stack. Alternatively, an annular insulator 1080 may be provided outside the flue, located radially outward (relative to ports 980) of adjacent groups of opposing raised port features 1050a and 1050b and disposed above the protrusion 840 to transfer compressive forces across the stack. The insulating layer 1070 and insulating gasket 1080 together or separately serve to seal the fluid flue (thereby defining a first fluid volume, separated from a second fluid volume), provide electrical isolation between the groups, and transfer compressive forces across the stack. The insulating layer may be selected so that it meets all of these requirements, and the gasket 1080 may be eliminated to further reduce parts count. Figures 9a to 9c The battery cell can be formed similar to Figure 10d In addition, Figure 10d The groups in the grouping arrangement can be referenced by Figures 6 to 7c Electrical connection as described.

[0138] Figure 10eAlternative electrical connections between pairs of battery cells of two groups in a stacked arrangement are shown. In this arrangement, a single battery cell 1020 is provided at the end of a group (which can be at the top or bottom of the group as shown). The single battery cell 1020 is similar to the battery cells described with reference to Figure 10a The single battery cell 1020 is attached (e.g., by welding or soldering) to a non- porous metal plate 1021 to form an enclosed fluid volume between the single battery cell 1020 and the non-porous metal plate 1021 (i.e., there is no fluid communication from one side of the non-porous metal plate 1021 to the other side of the non-porous metal plate 1021 unless through a port of the non-porous metal plate 1021 that corresponds to a port in the battery cell 1020). A spacer plate 131 is disposed within the enclosed fluid volume between the single battery cell 1020 and the non-porous metal plate 1021, the spacer plate 131 being as previously described. The non-porous metal plate 1021 is a non-drilled metal substrate that does not have an active battery chemistry layer. The non-porous metal plate 1021 incorporates a hole to form a port in fluid communication with the battery cell 1020. The non-porous metal plate 1021 is shown as a flat, unformed plate, but can similarly have a formed port feature as the battery cell 1020.

[0139] From Figure 10e It can be apparent that, in contrast to Figure 10d , there is no insulating layer 1070 separating the groups in width; the electrically conductive support structure (divider 440) at the end of the first group directly contacts the non-porous metal plate 1021 at the end of the adjacent second group. The electrically conductive support structure (divider 440) is as previously described. An insulating layer or gasket 1071 disposed on the raised port feature 1050 of the battery cell at the end of the first group electrically isolates the raised port feature 1050 from the non-porous metal plate 1021 at the end of the adjacent second group and seals the fluid within the manifold. Thus, the adjacent groups are connected in series between them, and face-to-face contact over most of the battery area (through the divider 440) without the need for additional electrical connections. For example, a group can have all of its electrically conductive support structures (or interconnects) connected in parallel, and the outermost electrically conductive support structure (divider 440 or interconnect) can contact (physically and electrically) the non-porous metal plate at the end of the pair of battery cells (the pair including the non-porous metal plate 1021 and the battery cell 1020) of the adjacent group and be connected in series with it. In the adjacent group, the non-porous metal plate and substrate are at the same potential and are connected in parallel to all other metal substrates in the group. Thus, the parallel substrates in the adjacent group are interconnected through the series connection to the parallel connection interconnects in the first group.

[0140] The pair of battery cells (the pair including the non-porous metal plate 1021 and the battery cell 1020) at the end of a group can be used to reference Figure 10e Figure 2 ​The assembly of a pair of battery cells into the arrangement described in FIG. 9 will now be described with reference to Figure 6 And Figures 7a to 7b In the arrangement described with reference to

[0141] Assembly method (for spacerless battery cell pair)

[0142] A preferred assembly method for a novel arrangement of spacerless battery cell pairs will now be described with reference to Figure 11 to FIG. 15.

[0143] As shown in Figure 11 the battery cell comprises a metal substrate 120 having an uppermost first face and a lower second face. The metal substrate comprises a porous region 124 having an electrochemically active layer beneath. The electrochemically active layer comprises a cathode layer, an electrolyte layer, and an anode layer, as described previously. It will be appreciated that Figure 11 A portion of the battery cell is shown, with the length of the cell having been cut off (as shown, on the right-hand side) for clarity, and the cell would continue through the right-hand side of the figure in operation, with the metal substrate and electrochemically active layer extending, surrounded by a flange forming a continuous perimeter of the battery cell. Other ports can also be present.

[0144] Two ports 980a and 980b are shown in the battery cell; the ports are holes through the metal substrate 120. Radially outward from each port is an annular raised port feature 1050 Figure 11 shown as in the form of a grooved or concave ring). A protrusion 1040 is provided radially inward of the raised port feature 1050. The protrusion 1040 is illustrated as alternating up and down, and shaped as a flat-topped pyramid, but can have other cross-sectional shapes such as a cone, a dome, or a raised block, and can have a rounded top. The raised port feature 1050 is further surrounded by an upward protrusion 840 surrounding the raised port feature 1050 and radially outward. The protrusion 840 is illustrated as a raised block or a dome, but can have other cross-sectional shapes such as a cone, a flat-topped pyramid (and can be interspersed with downward protrusions).

[0145] The assembly process for a pair of battery cells begins with the formation of a first battery cell by stamping or pressing the metal substrate into shape, and forming the port hole perimeter flange 850, the protrusions 840 and 1040, and the raised port feature 1050 (with the protrusion 840 protruding in the same face / direction as the flange 850, and the raised port feature 1050 protruding in the opposite face / direction), as described in previous embodiments.

[0146] The porous region 124 and the electrochemically active layer 120 can be formed before or after (preferably the latter) the stamping or pressing of the metal substrate, by the methods described previously with respect to FIG. 1 and Figure 2 The methods described previously.

[0147] The port hole can also be referred to as a fuel port, as in MS-SOFC operation, the port hole delivers fuel (e.g., hydrogen gas) to the first fluid volume; and in MS-SOEC operation, the port hole delivers gas, e.g., hydrogen gas (as a product of the MS-SOEC cell) from the first fluid volume.

[0148] As shown in FIG. 12, a set of cell units includes one or more pairs of cell units formed using the methods described with respect to FIG. 11. Figure 12a and Figure 12b A second such cell unit is provided upside down and placed on the first cell to form a first pair of cell units arranged in back-to-back fashion. Figure 12a and Figure 12b A first metal substrate 120a and a second metal substrate 120b disposed above the first metal substrate 120a are shown. The two metal substrates 120a, 120b are welded together along a weld 1210 on the flange 850 to form a pair of cell units. Optionally, a spacer plate (such as spacer plate 131) is placed in the first fluid volume before the second cell unit is provided upside down to the first cell unit.

[0149] Figure 12b is a cross-sectional view through the port region of the pair of cell units. The projections 1040 alternate in direction (toward and away from the gap between the metal substrates 110a, 110b forming the pair of cell units) so as to transmit a compressive force through the stack of cell units. Figure 12a Once sealed, the inwardly projecting projections 1040 in the first and second cell units around the inner circumference of the annular raised port feature 1050 are in contact with each other in opposing and counter-acting relationship, as can be seen in the cross-sectional view of

[0150] The same applies to the projections 840 around the outer circumference of each annular raised port feature 1050. Figure 12b The method of assembly of the battery pack as described in any of the previous embodiments follows the sequence of

[0151] to FIG. 14. Figure 13 As shown in FIG. 12, a set of cell units includes one or more pairs of cell units formed using the methods described with respect to FIG. 11.

[0152] As shown in FIG. 12, a set of cell units includes one or more pairs of cell units formed using the methods described with respect to FIG. 11. Figure 13 Figure 11 As shown in FIG. 12, a set of cell units includes one or more pairs of cell units formed using the methods described with respect to FIG. 11.

[0153] ​The assembly process for the group begins with placing the conductive support structure 310 over the first cell pair assembly, contacting the electrochemically active layer 110 to provide an electrical connection to the upper layer of the electrochemically active layer 110. The conductive support structure 310 extends beyond the edge of the metal substrate on one or more of its faces, the placement of the conductive support structure 310 does not interfere with the chimney formed by the port and raised port features.

[0154] The conductive support structure can be a stamped metal sheet, similar to the conductive support structure 310 described previously, and can be in the form of a conductive mesh or similar (as described above with reference to the separator 440).

[0155] Figure 14a A third cell unit is shown, where a metal substrate 120c is assembled on the first cell pair assembly such that the conductive support structure 310 contacts the electrochemically active layer of the third cell unit. The raised annular port feature 1050c and the outward protrusion 1040 of the third cell unit contact the corresponding raised annular port feature and outward protrusion 1040 of the first cell pair assembly. Figure 14b A cross-sectional view through the port region of the cell unit is shown in Figure 14a A cross-sectional view through the port region of the cell unit is shown in

[0156] As shown in Figure 15a Edge tangs 1510 are also provided to electrically connect adjacent conductive support structures 310 outside the perimeter of the cell substrate. The electrical connection between the edge tangs of adjacent conductive support structures can be improved by welding across the joint face of the edge tangs.

[0157] Other cell units can be added in the manner described with respect to Figure 11 to FIG. 14 until each group reaches the desired number of cell pairs. In such groups, there is no need to place a gasket between the cell pairs around the fluid port to form a seal to make the cells into a complete welded assembly. Alternatively, a single cell unit is added in FIG. 14, cell pairs (as shown in FIG. 12) can be placed on each conductive support structure 310, however this makes the welding around the fluid port more difficult.

[0158] Figure 15a A group of cell units is shown, the group of cell units includes three pairs of cell units formed using the method described above. Figure 15b A cross-sectional view through the chimney region of the group of cell units is shown in Figure 15a A cross-sectional view through the chimney region of the group of cell units is shown in

[0159] The electrically conductive support structure 310 preferably includes tangs (metal fingers) 311, as shown. The tangs are pressed out of a flat metal sheet in rows. For example, successive tangs are pressed up and down out of the plane of the sheet. The tangs serve as electrical contacts to electrically interconnect the surfaces of the facing electrochemically active layers. Figure 14b Other steps are described for the assembly method of the battery stack. As shown in

[0160] Reference is made to Figure 15c Other steps are described for the assembly method of the battery stack. As shown in Figure 15c The stack of battery cells includes multiple sets of assemblies formed as previously described with reference to Figures 11 to 15b The electrically conductive support structure, the insulating layer, and the second electrically conductive support structure are provided on the set of battery cells of Figure 15, and then a second set of battery cells (similar to the set of battery cells of Figure 15) is provided thereon. Figure 15c Two sets of battery cells are shown separated by the insulating layer 1070, similar to Figure 10d The annular raised port features and the protrusions between the sets are also electrically isolated in a similar manner as shown in Figure 10d Figure 7, the edge tangs of the first set of battery cells are not connected to the edge tangs of the second set of battery cells. Figure 6

[0161] The pair of battery cells formed by folding

[0162] Figures 16-17 show an alternative arrangement for arranging the battery pairs formed in back-to-back or face-to-face (not shown) fashion. In this arrangement, at least one pair of battery cells is formed from a folded metal substrate such that the respective active layers of the opposing battery cells are deposited on and supported by a common substrate. Since the metal substrate is electrically conductive, the electrodes closest to the metal substrate are electrically connected and at the same potential.

[0163] Figure 16a One arrangement of a pair of folded battery cells 1600a, 1600b is shown, in which the metal substrate 120 is in the form of a U-shape. The metal substrate 120 is formed by folding a metal sheet or continuous metal substrate 180 degrees at a fold region 1620. The metal sheet is provided with two porous regions and two electrochemically active layers 110a, 110b, which are sealingly covered in the regions at two respective locations on the first face 125 of the metal sheet, with the fold region 1620 located between the two electrochemically active layers 110a, 110b. For SOFCs, the two porous regions and associated electrochemically active regions 110 are separated, i.e., distinct; that is, the electrochemically active regions 110 are not deposited in the region of the fold region 1620, as the electrochemically active regions 110 are not flexible.

[0164] As shown in Figure 16a ​As shown, once folded at the fold region 1620 by 180 degrees, the electrochemically active layers are superimposed and aligned, occupying respective substantially parallel (flat) planes in a back-to-back (or face-to-face) arrangement. The fold region 1620 at the folded end of the folded cell pair can comprise two 90 degree folds, one of which is a shorter segment, which produces the height of the first fluid volume 140.

[0165] Ports can be formed in the substrate 120 between the electrochemically active region 110 and the fold region 1620 (and, at the other end of the folded substrate, between the electrochemically active region 110 and the edge of the substrate) to form flues to supply (and / or discharge) the first (and / or second) fluid volumes; thus the first (second) fluid volumes are internally manifolded.

[0166] The first fluid volume 140 can be sealed at the other end 1630 (i.e. the end distal to the fold region 1620) using a (e.g. conductive) spacer plate (such as the spacer plate 130 welded to the metal substrate 120), as described with respect to Figure 16b Further description.

[0167] The arrangement of the cell pair 1600 forms a repeating unit, and can be used to replace the cell pair 200 in the battery stack described with respect to Figures 4 to 10.

[0168] As previously described, if for a solid oxide cell, typically the electrochemically active layers comprise an anode layer 113, an electrolyte layer 112 and a cathode layer 111 deposited on the porous region 124, and there can also be an extended electrolyte coating 123. The metal substrate (in the same polarity as the innermost electrode) can be connected to an electrical connection (not shown).

[0169] Figure 16bThe respective folded pairs of battery cells 1600a, 1600b are shown how they can be stacked on top of one another to form a group 1640 of battery cells. The group 1640 is similar to the groups described with reference to FIGS. 4-10. The folded pairs of battery cells 1600a, 1600b have a spacer plate 130 or gasket that seals the first fluid volume 140, respectively. The gaskets 180a, 180b (which can be electrically conductive as previously described) and the electrically conductive support structure 310 are positioned between adjacent folded pairs 1600a, 1600b. Between these pairs of battery cells, the gaskets 180a, 180b seal an internal manifold that provides fluid communication between adjacent battery pairs to the first fluid volume. The electrically conductive support structure 310 provides electrical contact to the outermost electrodes of the electrochemically active layers 110 of the adjacent folded cells 1600a, 1600b, which have opposite polarity to the metal substrate, and can be connected to an electrical connector (e.g., for power output). A support structure (not shown) can be provided in the first fluid volume 140 to resist bending of the metal substrate 120. Two or more groups 1640 can be arranged, as previously described with reference to FIGS. 4-10. Figure 5

[0170] Figure 16c Folded pair battery cells 1650 are shown in a back-to-back arrangement, and include shaped port features 840, 910, 1040 as well as a perimeter flange 850. The shaped port features maintain a chimney for transport and venting of the first fluid volume 140, thereby eliminating the need for gaskets 180a, 180b. Thus, the arrangement has an internal manifolded first fluid volume (i.e., the ports and shaped port features define an inlet and an outlet to and from the first fluid volume 140 of each pair of battery cells). The second fluid volume can be 1) similarly internal manifolded by way of other ports and shaped port features that provide an inlet to and an outlet from the second fluid volume (not shown), or 2) can be external manifolded by way of a second fluid that flows around the pair of battery cells.

[0171] The folded pair battery cells 1650 can be substantially similar to the battery cell pairs described with reference to Figure 9b Figure 10b and Figure 16a , except that the perimeter flange 850 has a folded strap 1620 at one end. The folded strap 1620 is shown in place of one end of the perimeter flange 850. The perimeter flange 850 is present at least at the end opposite the folded region 1620, and preferably around all three edges of the battery (e.g., a rectangular battery). Alternatively, the perimeter flange 850 remains at all edges of the battery (e.g., all four edges of a rectangular battery), and the folded region 1620 is incorporated into the flange 850 (as shown in FIG. 1650b). The folded strap 1620 can be a folded region of the perimeter flange 850, or can be a separate piece of material that is attached to the perimeter flange 850. Figure 17b ​​The first fluid volume 140 is defined by the perimeter of the metal substrate 120, the perimeter flange 850, and the perimeter of the flange 950. The first fluid volume 140 is sealed by welding the perimeter flange 850 to the perimeter flange 950.

[0172] This pair of cell units 1650 is formed from a metal sheet with shaped features that are folded at the fold region 1620. The shaped features are made by pressing a flat metal sheet. The shaped features include a protrusion 840 around the chimney (in the form of a dimple), a chimney protrusion 910 (which can be annular and sealed with or without a gasket), and a protrusion 1040 outside the chimney. The protrusions 840 and 1040 assist in defining the first fluid volume 140 by resisting the compressive forces of the stack. Support structures 131 can be positioned between the porous regions of the substrate 120 to prevent the substrate 120 from bending so as to define the first fluid volume 140. The electrochemically active layers 110 can be deposited on the porous regions 124 of the metal substrate 120 before or after the metal sheet is folded.

[0173] Figure 17a An alternative arrangement of cell units 1700 is shown, in which four electrochemically active regions 110 share the same metal substrate 120. The metal substrate 120 is formed from a metal sheet or continuous metal substrate that is folded at fold regions 1720a, 1720b, and 1720c. The single metal sheet is provided with four porous regions on which the four electrochemically active regions 110 are deposited on the first face 125, respectively. For SOFC or SOEC, the four porous regions and electrochemically active regions 110 are distinguished. The single metal sheet is folded by 180 degrees at the first fold region 1720a in a first direction (clockwise, as shown) to form the metal substrate 120. Figure 17a The single metal sheet is folded by 180 degrees at the second fold region 1720b in a second direction (counter-clockwise, as shown) to form the metal substrate 120. Figure 17a The single metal sheet is folded by 180 degrees at the third fold region 1720c in a first direction (clockwise, as shown) to form the metal substrate 120. Figure 17a The single metal sheet is folded by 180 degrees at the third fold region 1720c in a first direction (clockwise, as shown) to form the metal substrate 120. Figure 17a The single metal sheet is folded by 180 degrees at the third fold region 1720c in a first direction (clockwise, as shown) to form the metal substrate 120.

[0174] The support structure 131 can help to connect opposing electrodes from adjacent electrochemically active layers 110, but its primary role is to define the first fluid volume 140. The current collector 310 collects current from the opposing (outermost) electrodes of adjacent electrochemically active layers 110, and defines the second fluid volume 430 (support structure not shown in the first fluid volume, but shown in the second fluid volume in Figure 17a , where the support structure electrically connects the outermost electrodes of the active layers (optionally through contact adhesive)). The skilled person will appreciate that a single metal plate can be provided with substantially any number of electrochemically active regions and a corresponding number of fold regions to provide a sawtooth battery with a corresponding number of pairs of battery cells. The limiting factor is typically the amount of current that can be drawn from multiple batteries on the same common substrate.

[0175] The arrangement of battery cells 1700 on a single metal substrate 120 can provide for spacer plates 130 or gaskets at the ends to seal the first fluid volume 140, and can be used as a single pack. Multiple packs can be arranged to form a stack of battery cells, as previously described.

[0176] Figure 17b An arrangement of battery cells 1750 in a back-to-back arrangement is shown, and includes shaped port features 840, 910, 1040, and a perimeter flange 850. This pair of battery cells 1750 is substantially similar to those described with reference to Figure 9b , Figure 10b , and Figure 17a . The fold region 1720 is shown as a portion of the formation of the perimeter flange 850; alternatively, the fold region 1720 can replace a portion of the perimeter flange (as shown by the fold strap 1620 in Figure 16c . The perimeter flange does not necessarily have to be welded at the first fold region 1720a and the third fold region 1720c, but the flange of the adjacent second fold region 1720b is welded to seal the first fluid volume 140.

[0177] As Figure 17bAs shown, the two pairs of cell units 1750 are formed from a single sheet of metal with formed features that are folded at the fold regions 1720. The formed features are made by pressing a flat sheet of metal. The formed features include a protrusion 840 around the chimney (in the form of a dimple), a chimney protrusion 910 (which can be annular and sealed using or not using a gasket), and a protrusion 1040 outside the chimney. The protrusions 840 and 1040 assist in defining the first fluid volume 140 by resisting compression of the stack. The chimney is used to pass fuel (e.g., hydrogen gas) to the first fluid volume 140 when the cell unit is operating as a SOFC, and to exhaust (e.g., hydrogen gas) from the first fluid volume when the cell unit is operating as a MS-SOEC. A second chimney can be used to exhaust the first fluid volume when the cell unit is operating as a MS-SOFC, and to provide fluid to the first fluid volume when the cell unit is operating as a MS-SOEC. The electrically conductive support structures 310a can be positioned between the porous regions of the substrate 120 to prevent the substrate 120 from bending so as to define the first fluid volume 140. The electrically conductive support structures 310b can be positioned between the electrochemically active layers 110 to assist in electrical interconnection therebetween and to prevent the substrate 120 from bending so as to define the second fluid volume 430. The electrochemically active layers 110 can be deposited on the porous regions 124 of the metal substrate 120 prior to folding the sheet of metal. Referring to Figure 17b The two pairs of cell units 1750 described can be used as a single set of cell units, and multiple sets can be arranged to form a stack, as previously described herein.

[0178] The stack of folded pairs of cell units is internally manifolded, that is, they have ports within the metal substrate 120 to form internal manifold(s) or chimneys that connect the first fluid volume 140 of each pair of cell units.

[0179] REFERENCE NUMERALS:

[0180] Prior Art - Introduction Only

[0181] 90 fuel cell repeating unit

[0182] 110 electrochemically active layer

[0183] 111 cathode layer

[0184] 112 electrolyte layer

[0185] 113 anode layer

[0186] 120 metal substrate

[0187] 124 porous region

[0188] 130 spacer plate

[0189] 140 first fluid volume

[0190] 150 interconnect

[0191] 160 large space / aperture

[0192] 180a,b gasket

[0193] 188 oxidant port / manifold

[0194] 200 port / manifold

[0195] Figure 2 To Figure 17

[0196] 110 electrochemically active layer

[0197] 111 cathode layer

[0198] 112 electrolyte layer

[0199] 113 anode layer

[0200] 120 metal substrate

[0201] 123 extended electrolyte coating

[0202] 124 porous region

[0203] 125 first face of metal substrate

[0204] 126 second face of metal substrate

[0205] 130 spacer plate

[0206] 131 support structure

[0207] 140 first fluid volume

[0208] 141 first fluid volume

[0209] 180 gasket

[0210] 200 cell pair

[0211] 300 cell pair

[0212] 310 electrically conductive support structure / current collector

[0213] 311 interconnect tab

[0214] 400 cell group

[0215] 430 second fluid volume

[0216] 440 electrically conductive support structure

[0217] 500 cell stack

[0218] 510 insulating layer

[0219] 530 electrically conductive support structure

[0220] 610 bus bar electrically contacting anodes

[0221] 615 bus bar electrically contacting cathodes

[0222] 620 bus bar electrically contacting anodes and cathodes

[0223] 630 electrically conductive support structure

[0224] 700 cell stack

[0225] 710 cell group

[0226] 711 bus bar electrically contacting anodes and cathodes

[0227] 715 bus bar electrically contacting anodes

[0228] 720 bus bar electrically contacting anodes and cathodes

[0229] 730 electrically conductive gasket

[0230] 731 electrically conductive gasket

[0231] 750 cell stack

[0232] 805 cell pair

[0233] 810 shaped cell

[0234] 840 protrusion

[0235] 850 flange

[0236] 870 cell group

[0237] 905 cell pair

[0238] 910 raised port feature

[0239] 980 fluid port

[0240] 1020 cell

[0241] 1021 non-porous metal plate

[0242] 1040 chimney protrusion

[0243] 1050 raised port feature

[0244] 1070 insulating layer

[0245] 1071 insulating layer / insulating spacer

[0246] 1080 insulating spacer

[0247] 1200 flue

[0248] 1210 weld path

[0249] 1600 cell pair

[0250] 1620 fold region

[0251] 1630 end of cell pair

[0252] 1640 cell group

[0253] 1650 cell pair

[0254] 1700 cell

[0255] 1720 fold region

[0256] 1750 cell

Claims

1. A metal-supported planar battery arrangement comprising: At least one pair of batteries, Each cell comprises: a metal substrate having a first side and a second side and a porous region providing fluid communication between the sides; planar cell chemistry layers including a fuel electrode, an electrolyte, and an air electrode layer, the fuel electrode, electrolyte, and air electrode layers being coated or deposited on and supported by the porous region on the first side; Its characteristics are: A plurality of said metal substrates are arranged with their battery chemical layers in a stacked manner such that their two first faces or two second faces face inwardly in a spaced, opposing relationship, the inwardly facing faces thereby defining a common first fluid volume for one of the fuel or the oxidant, with a permeable support structure within the common first fluid volume to maintain a spacing between the two inwardly facing faces.

2. The battery arrangement according to claim 1, characterized in that The plurality of metal substrates include two independent metal plates, which are directly or indirectly connected together to form the stacked arrangement.

3. The battery arrangement according to claim 2, characterized in that The two metal plates are indirectly connected together to form the stacked arrangement. Optionally, a metal spacer plate is provided between the two metal plates.

4. The battery arrangement according to claim 2, characterized in that The two metal plates are directly connected together such that they abut one another to form the stacked arrangement, wherein one or both of the metal plates have shaped features that form the first fluid volume between the metal plates.

5. The battery arrangement according to claim 1, characterized in that The plurality of metal substrates are formed as a continuous metal substrate having a first side, with a pair of battery chemistry layers respectively coated or deposited on the porous areas of the first side, and the continuous metal substrate is folded between the battery chemistry layers so that they overlap each other to form a pair of folded cells that define a first fluid volume for one of a fuel or an oxidant.

6. The battery arrangement according to claim 5, characterized in that The invention comprises a plurality of pairs of folded batteries, which are stacked adjacent to each other in a battery pack.

7. The battery arrangement according to claim 6, characterized in that In the battery pack, each pair of folded batteries is formed by independent respective metal substrates, which are folded once so as to have only one folded end enclosing the first fluid volume.

8. The battery arrangement according to claim 5 or 6, characterized in that Adjacent pairs of folded cells are formed from a common continuous metal substrate that is folded multiple times to have a plurality of opposing folded ends and define a plurality of respective first fluid volumes for one of a fuel or an oxidant.

9. A battery arrangement according to any one of the preceding claims, characterized in that At least one of the metal substrates includes a flange peripheral feature, and the metal substrates are sealed together about the flange peripheral feature to form the common first fluid volume therebetween.

10. A battery arrangement according to any one of the preceding claims, characterized in that At least one fluid port is provided through an opening in each of the metal base plates, the respective fluid ports being aligned with each other in the stacking direction and communicating with the common first fluid volume.

11. The battery arrangement according to claim 10, characterized in that At least one of the metal substrates includes a molded port feature formed around a port thereof, the molded port feature extending inwardly within the common first fluid volume, elements of the molded port feature being laterally spaced from one another to define a fluid path between the elements of the port to enable passage of fluid from the port to the common first fluid volume.

12. The battery arrangement according to claim 10 or 11, characterized in that At least one of the metal substrates includes a formed port feature formed around a port thereof, the formed port feature extending outwardly away from the common first fluid volume.

13. A battery arrangement according to any one of the preceding claims, characterized in that The inwardly facing surface defines a first fluid volume for fuel.

14. A battery arrangement according to any one of the preceding claims, characterized in that The inwardly facing surface is the second surface of the metal substrate.

15. A battery arrangement according to any one of the preceding claims, characterized in that A plurality of cell pairs are stacked adjacent to one another to form a group of cells, whereby at least one second fluid volume is defined between adjacent cell pairs, and the at least one second fluid volume is used for the other of a fuel or an oxidant.

16. The battery arrangement according to claim 15, characterized in that Adjacent first fluid volumes are in fluid communication with each other by passage of fluid through openings provided in the respective metal substrates, the openings being aligned in the stacking direction to form an internal passage within the battery pack.

17. The battery arrangement according to claim 16, characterized in that The internal passage is sealingly defined by a gasket positioned between the pair of cells in the battery pack.

18. The battery arrangement according to claim 15, characterized in that All fuel electrodes in the stack are electrically connected to each other, and / or all air electrodes in the stack are electrically connected to each other.

19. The battery arrangement according to claim 15, characterized in that All corresponding pairs of cells in a battery pack are welded together, and all base plates are electrically connected.

20. The battery arrangement according to claim 15, comprising a plurality of battery groups stacked on top of each other, characterized in that The fuel electrodes in one group are connected in series to the air electrodes in the next adjacent group.

21. The battery arrangement according to claim 15, comprising a plurality of battery groups stacked on top of each other, characterized in that: Insulation plates are provided between adjacent groups to prevent direct electrical contact between the adjacent groups.

22. The battery arrangement of claim 15, comprising a plurality of battery groups stacked one on top of the other, wherein: At the ends of the groups are provided individual cells which make direct electrical contact with adjacent cells of an adjacent group in order to connect the adjacent groups in series.

23. A method for assembling a metal-supported planar battery arrangement, characterized in that: include: providing a first cell and a second cell, each cell comprising: a metal substrate having a first face and a second face and a porous region providing fluid communication between the faces; Planar battery chemistry layers comprising a fuel electrode, an electrolyte, and an air electrode layer, said fuel electrode, electrolyte, and air electrode layers being coated or deposited on and supported by said porous area on said first side; and inverting one of said batteries relative to another so that said metal substrates arrange their battery chemistry layers in a stacked manner so that their two first sides or their two second sides face inwardly in a spaced, opposed relationship so as to define therebetween a common first fluid volume for one of the fuel or oxidant so as to form said battery arrangement with a permeable support structure within the common first fluid volume to maintain spacing between the two inwardly facing sides.

24. The method according to claim 23, wherein Also includes: At least one other cell arrangement is provided in the same manner as the first cell arrangement, and the respective cell arrangements are stacked to form a group of cells, and all fuel electrodes within a group or all air electrodes within a group are electrically connected.

25. The method according to claim 23 or 24, characterized in that The method also includes stacking the corresponding batteries to form a battery stack.

26. The method according to any one of claims 23 to 25, characterized in that A plurality of the metal substrates are formed as a continuous metal substrate, and the inverting includes folding the continuous metal substrate between the battery chemistry layers so that they overlap each other to form a pair of folded batteries, the folded battery pair defining the first fluid volume for one of a fuel or an oxidant.

27. The method according to claim 26, characterized in that Before the continuous metal substrate is inverted by folding to form a folded pair, the battery chemical layers of the battery pair are respectively coated or deposited on the first side.

28. The method according to claim 27, characterized in that Also includes: Prior to coating or depositing the battery chemistry layers, a pre-fold is created on the metal substrate.

29. The method according to any one of claims 23 to 28, characterized in that Also includes: Openings are cut through each of the metal substrates to form at least one inlet port and at least one outlet port.

30. The method according to claim 29, wherein Also includes: At least one of the metal substrates is pressed about its port to form a formed port feature that extends inwardly into the common first fluid volume and / or outwardly away from the common first fluid volume.

31. The method according to any one of claims 23 to 30, characterized in that Also included is pressing at least one of the metal substrates to form a flange peripheral feature before inverting the battery.

Images