Battery unit and battery stack

Abstract

A stack of rectangular, planar electrochemical battery units (200), each battery unit (200) having at least one first intermediate fluid port (230, 235) disposed midway along the length of or between one or more active battery chemical regions (210) and in fluid communication with a first fluid volume of the battery unit (200). The first intermediate fluid ports (230, 235) of each battery unit (200) are aligned to form at least one first intermediate fluid passage extending in the stack direction. The stack is configured such that, in each first fluid volume, a first fluid flow path (405, 410) extends across one or more active battery chemical regions (210) between the at least one first intermediate fluid port (230, 235) and each corresponding opposing battery end.

Description

Technical Field

[0001] The present invention relates to a stack comprising a plurality of electrochemical battery units. More particularly, the present invention relates to a metal-supported battery, in particular a metal-supported solid oxide fuel cell unit of either the oxide type (MS-SOFC) or the electrolyte type (MS-SOEC) and stacks thereof.

Background Art

[0002] Depending on the fuel cell unit, power can be generated by using an electrochemical conversion process that oxidizes fuel to generate electricity. Further, or alternatively, depending on the fuel cell unit, it can function as a regenerative fuel cell (or reverse fuel cell) unit, often known as a solid oxide electrolyte fuel cell unit, for example, to separate hydrogen and oxygen from water, or carbon monoxide and oxygen from carbon dioxide. This can be in a tubular or planar shape. The planar fuel cell units can be arranged in a stack configuration, for example, with 100 to 200 fuel cell units stacked on top of each other, and the individual fuel cell units are electrically arranged in series.

[0003] A solid oxide fuel cell that generates electricity is based on a solid oxide electrolyte that conducts oxygen anions from the cathode to the anode, which are located on both sides of the electrolyte. At this time, the fuel or reformed fuel contacts the anode (fuel electrode), and an oxidant such as air or an oxygen-rich fluid contacts the cathode (air electrode). Conventional ceramic-supported (e.g., anode-supported) SOFCs have low mechanical strength and are prone to damage. Therefore, in recent years, metal-supported SOFCs having an active fuel cell component layer supported on a metal substrate have been developed. In these cells, since the ceramic layer only serves an electrochemical function, it can be made very thin. That is, the ceramic layer is not self-supporting, but rather a thin coating / film laid on and supported by the metal substrate. Such a metal-supported SOFC stack is more robust, less costly, and has excellent thermal properties than a ceramic-supported SOFC, and can be manufactured using conventional metal welding techniques.

[0004] International Publication No. WO 2015 / 136295, which is the applicant's previous patent application, discloses a metal-supported SOFC having an anodic, electrolyte, and cathodic layer in which an electrochemically active layer (or active fuel cell component layer) is respectively deposited (e.g., as a thin coating / film) on a metal support plate 12 (e.g., foil) and supported by the metal support plate 12 (e.g., foil). The metal support plate has a porous region surrounded by a non-porous region such that gas can pass through pores from one side of the metal support plate to the opposite side and access the active layer coated thereon, and the active layer is deposited on the porous region. As shown in FIG. 1, the fuel cell unit 9 includes three plates or layers: a metal support plate 12, a separator plate 50, and a spacer plate 13 sandwiched therebetween. The fuel cell unit 9 further has fluid ports 20, 88 (for oxidant or fuel), and the three plates are stacked on one another and welded (fused) via the spacer plate 13 to form a single metal-supported solid oxide fuel cell unit in which a central fluid volume is defined by a large space 14 provided in the spacer plate 13. The metal components of the repeating layers of the fuel cell stack are in electrical contact with each other, and the flow of electrons between them mainly passes through the fusion / welding path, thereby avoiding contact resistance losses between the surfaces.

[0005] As discussed in International Publication No. WO 2015 / 136295, the porous region has small openings (holes drilled through the metal foil substrate) (not shown) that extend through the metal support plate 12 and overlap with the anode (or cathode depending on the polarity orientation of the electrochemically active layer) disposed under the metal support plate 12. These are disposed in a large space or opening 14 defined by the spacer plate 13 such that the fluid volume communicates with the electrochemically active layer on the lower surface of the support plate 12 through the small openings.

[0006] The separator plate 50 is provided with upper and lower corrugations 60 that extend to the cathode (or anode depending on the polarity orientation of the electrochemically active layer) of a subsequent fuel cell unit stacked on this fuel cell unit and also extend to the metal support plate 12 of its own fuel cell unit. Thus, this electrically connects adjacent fuel cell units in the stack and arranges the electrochemically active layers (usually one for each fuel cell unit) of the stack in series with each other.

[0007] It is known to provide a single central port in a circular fuel cell unit (for example, International Publication No. WO 2005 / 064725 and U.S. Patent Application Publication No. US 2011 / 123890), and the electrochemically active layer may be in the form of an annular segment around the central port (for example, International Publication No. WO 2005 / 064725) or in the form of a ring around the central port. Such a structure is significantly different from a rectangular cell unit considering their high symmetry.

[0008] U.S. Patent Application Publication No. US 2013 / 0177829 and U.S. Patent Application Publication No. US 2012 / 0295182 provide a central manifold in a separator of a double - plate configuration. The separator has a "paddle" or "H" shape. There are a pair of elongated channels extending in opposite directions within the separator, and at the distal ends of the channels away from the central manifold, each pair of self - supporting electrolyte electrode assemblies is supplied.

[0009] International Publication No. 2008 / 123968 relates to a stack of battery units having a central port with a self-supporting electrolyte electrode assembly.

[0010] Japanese Patent Application Laid-Open No. 2013 / 187005 relates to a battery unit having two self-supporting electrolyte electrode assemblies disposed in a separator, the separator having a central port for cooling air. The battery unit may be formed in a stack and fixed using bolts passing through the central port.

[0011] A solid oxide electrolyte cell (SOEC) can have the same structure as an SOFC, but essentially the SOFC operates in reverse, i.e., in a regeneration mode, and electrolyzes water and / or carbon dioxide by using a solid oxide electrolyte to produce hydrogen gas and / or carbon monoxide and oxygen.

Summary of the Invention

[0012] The present invention relates to a stack of repeating solid oxide fuel cell units having a structure suitable for use as an SOEC or an SOFC. For convenience, both the SOEC or SOFC stack battery unit will hereinafter be referred to as a "battery unit" (i.e., meaning an SOEC or SOFC stack battery unit).

[0013] The present invention endeavors to provide a cost-effective battery unit while improving the efficiency of the fuel cell unit. Reducing the manufacturing cost of fuel cells would be a great benefit in reducing the entry cost of energy production by fuel cells.

[0014] The present invention provides a stack of rectangular planar electrochemical cell units, each cell unit being arranged within or at the mid-length between one or more active cell chemical substance regions and comprising at least one first fluid intermediate port in fluid communication with a first fluid volume of the cell unit, the first fluid intermediate ports of respective cell units being aligned to form at least one first fluid intermediate passage extending in the stack direction, and in each first fluid volume, the stack being configured such that a first fluid flow path extends across one or more active cell chemical substance regions between at least one first fluid intermediate port and each corresponding opposing cell end.

[0015] Thus, the first fluid flow path may extend in the opposite direction (e.g., the length direction) across one or more active cell chemical substance regions between at least one first fluid intermediate port and each corresponding opposing cell end. Such an arrangement of the flow path means that one or more active cell chemical substance regions may be arranged between the intermediate port and each corresponding opposing cell end. The active cell chemical substances arranged on both sides of the intermediate port have less pressure drop across the region as a whole and the fluid travels a shorter distance to utilize the active cell chemical substance region(s) than when the flow path extends in the length direction from one cell end to the opposing cell end across the cell chemical substance. Thus, the differences in temperature and fuel supply / consumption can be reduced across the chemical substances as a whole.

[0016] The flow path is between the intermediate port and each respective opposing end, but the fluid flow itself spreads fan-like between the intermediate port and the opposing cell end across the active cell chemical substance region. Nevertheless, while the flow spreads fan-like, there are (main) components of the fluid flow path that extend (e.g., in the length direction) between the intermediate port and each cell end.

[0017] The active battery chemical regions may share the same intermediate port and be at the same distance therefrom. This effectively reduces the number of ports required per unit area of the active battery chemical, thereby increasing the power density of each battery unit. This results in an increased proportion of the battery unit area covered by the active battery chemical, a shorter fluid flow path length, and a more thermally ideal battery unit with fewer ports. A shorter fluid flow path length means that the temperature gradient along the flow path can be smaller. The intermediate port(s) may extend in the stacking direction through the height of the stack.

[0018] The stack is configured such that, in use, a first fluid flow path extends in opposite directions between at least one first fluid intermediate port and each corresponding opposing battery end. The flow path may be symmetric with respect to the center of the rectangular battery unit. In fact, the ports do not necessarily need to induce the fluid flow path, and the fluid flow from the ports may be non-directional (there may be no meandering flow path defined within the battery unit). In other words, the flow path around the intermediate port (i.e., from or to the intermediate port) is substantially radial. That is, the flow path is not restricted to the flow path around the intermediate port (i.e., from or to the intermediate port). One or more active battery chemical regions may substantially surround the intermediate port.

[0019] The intermediate port may be disposed in the middle of both the length and width of the battery unit. The rectangular battery unit includes square battery units where the length and width of the battery unit are equal. The battery unit may be elongated, in which case the battery unit has a length greater than the width or vice versa. The rectangular battery unit may have rounded or circular corners disposed between two pairs of parallel edges.

[0020] The rectangular battery unit may have two pairs of substantially parallel sides. If the length of the first pair of sides is greater than the length of the second pair of sides, the fluid intermediate port may be disposed in the middle of the length of the first pair of sides.

[0021] The battery unit may include a metal support plate and a separator plate, between which a first fluid volume portion is defined and accommodated. In the stack, a second fluid volume portion may be defined between adjacent battery units. The battery unit may include a metal-supported solid oxide fuel cell unit.

[0022] Each battery unit may include a separator plate and a metal support plate that holds an active battery chemical region (s) provided on a porous region on its first side surface. The separator plate and the metal support plate overlap each other to form a battery unit. At least one fluid port may be provided on each of the separator plate and the metal support plate, and these are aligned to form respective first fluid intermediate ports and first fluid passages.

[0023] Normally, each battery unit has at least two separate active battery chemical regions, and each region is disposed between an intermediate port and each opposing battery end, respectively.

[0024] The separate active battery chemical regions may be disposed on both sides of the intermediate port. Smaller separate active battery chemical regions generally have lower stress than a single region of equal area, thus reducing the likelihood of stress-related failures.

[0025] Alternatively, each battery unit may have a continuous active battery chemical region, and the intermediate port (s) is disposed within or surrounded by the active battery chemical region. The continuous active battery chemical region may be a single region in each battery unit.

[0026] Normally, parallel to the fluid flow path, the dimension of the active battery chemical region between an intermediate port and one of the opposing ends of the battery unit is less than or equal to the dimension of the active battery chemical region perpendicular to the fluid flow path.

[0027] The dimension of the active battery chemical substance region between the intermediate port and one of the opposing ends of the battery unit, parallel to the fluid flow path, may be the shortest distance from the edge of the active battery chemical substance region close to the intermediate port to the opposing edge of the active battery chemical substance region close to the end of the battery unit.

[0028] The length of the battery unit can be referred to as the dimension of the battery unit generally parallel to the fluid flow path, and the width of the battery unit can be referred to as the dimension generally perpendicular to the fluid flow path. Usually, the length of the flow path across the active battery chemical substance region (between the intermediate port of the battery unit and each end) is about half of the length of the battery unit, more specifically 45% or more of the length of the battery unit. When discussing the width of the battery chemical substance (i.e., the dimension of the battery chemical substance generally perpendicular to the flow path), it may usually be assumed to be 90% or more of the width of the battery unit (the width of the battery unit is the dimension of the battery unit generally perpendicular to the flow path). Thus, the proportion of the battery unit area covered by the active battery chemical substance region can be maximized. When manufacturing the battery unit and the stack, since even a small increment in effective battery coverage can have a significant impact on the power density, it is desirable to arrange the active battery chemical substance region as close as possible to the port(s) and the vicinity of the battery outer periphery. Thus, the aim is to minimize the proportion of the battery area not covered by the active battery chemical substance region.

[0029] In some embodiments, the distance between at least one first fluid intermediate passage and each battery end is less than the width of the battery unit (the width is generally perpendicular to the fluid flow path which is a line between the intermediate passage and the battery end), but not necessarily so.

[0030] In some embodiments, the length of the battery unit is about 2.4 times or less the width of the battery unit, and there may be embodiments where the length is actually smaller than the width. Preferably, the length of the battery unit is 1.5 to 2.4 times the width of the battery unit. More preferably, the length of the battery unit is 2 times or less the width of the battery unit.

[0031] In a preferred embodiment, the fluid flow path traverses the dimension of the active battery chemical substance layer that is the shorter of the length and width dimensions of the active battery chemical substance layer. Thus, the battery unit may have a low aspect ratio. The aspect ratio may be defined as the dimension of the active battery chemical substance region parallel to the fluid flow path divided by the dimension of the active battery chemical substance region perpendicular to the fluid flow path. A low aspect ratio means that the ratio of the width of the active battery chemical substance layer (the distance across the active battery chemical substance region between the inlet port and the outlet port) to the length is less than 1.2, preferably between 0.3 and 1.2. It is preferred that the aspect ratio is less than 1. More preferably, the aspect ratio is less than 0.8, and even more preferably, the aspect ratio is between 0.3 and 0.8. A very low aspect ratio (e.g., an aspect ratio less than 0.3) is advantageous for the performance of the battery, but these are limited due to manufacturing constraints.

[0032] The fluid flow path traversing the shorter dimension can a) improve the heat distribution because the conduction path length from the high-temperature inlet to the lower-temperature outlet decreases (as a result of the fluid entering or exiting the fluid volume portion in the middle of the length of the battery unit), and b) reduce the pressure drop between the intermediate fluid passage and the battery end or the end fluid passage, leading to an improvement in the net efficiency of the stack because the parasitic losses from the fluid blower and / or pump are reduced. The improved heat distribution, i.e., a smaller heat density gradient, can also lead to a decrease in the current density gradient.

[0033] Each battery unit may have only one first fluid intermediate port that is in fluid communication with the first fluid volume portion.

[0034] Each battery unit may have only one first fluid intermediate port, in which case the first fluid flow path branches and extends in two opposite directions between at least one first fluid intermediate port and each corresponding battery end. By having only one first fluid intermediate port, a greater proportion of the battery unit is used for the active battery chemical layer, thereby enabling a greater power density. Alternatively, for example, there may be a plurality of first fluid intermediate ports arranged along a line intermediate between the ends of the battery unit (i.e., on both sides of the middle of the length of the battery unit and / or between the active battery chemical regions).

[0035] Alternatively, for example, a plurality of first fluid intermediate ports may be arranged on both sides of each minor axis line (i.e., on both sides of the middle of the length of the battery unit), so that all the flow from one intermediate port tends to be directed only to a corresponding one battery end.

[0036] Typically, at least one first fluid end passage is provided extending in the stack direction at or near each respective opposing stack end. Thus, the stack may be configured such that its intermediate and end first fluid passages form an inlet passage and an outlet passage, or vice versa, within the stack to supply the first fluid to the first fluid volume of each battery unit during use, so that the first fluid flow path extends across one or more active battery chemical regions of each battery between its intermediate port and both opposing battery ends.

[0037] One or both of the first fluid end passages may be manifolded externally around the stack end. However, typically the first fluid end passages are manifolded internally by providing suitable seals / gaskets between adjacent batteries, for example, to aligned first fluid end ports extending in the stack (axis) direction within the battery unit.

[0038] The first fluid volume portion may be a fluid volume portion of air or fuel. Each battery may include at least one active battery chemical substance region having an electrolyte interposed between an air electrode and a fuel electrode, and each battery includes an air / oxidant fluid volume portion and a fuel fluid volume portion that communicate with each of the air electrode and the fuel electrode, respectively. Accordingly, the intermediate and end fluid passages may each form an inlet passage and an outlet passage for supplying fluid to the same respective fluid volume portions of each battery that may be an air fluid volume portion or a fuel fluid volume portion.

[0039] In one embodiment, each battery unit includes at least a first fluid end port and a second first fluid end port disposed respectively at or near each opposing battery end, and the respective first fluid end ports are aligned to define corresponding first interiors and second interiors, and the first fluid end passage extends in the stack direction, whereby the intermediate and end first fluid passages each form an inlet passage and an outlet passage, or vice versa, within the stack for supplying a first fluid to the first fluid volume portion of each battery unit.

[0040] The end port provides an internal manifold for the first fluid. This helps to surround the first fluid volume portion and means that it is easy to seal the first fluid volume portion from the second fluid volume portion. The active battery chemical substance region and the intermediate port(s) are disposed between the corresponding fluid end ports. For this reason, the fluid flow path between each end port and the intermediate port(s) passes over the active battery chemical substance region and delivers and removes fluid therefrom (i.e., in SOFC operation, delivers fuel and removes exhaust from the fuel volume portion, or delivers an oxidant and removes exhaust from the oxidant volume portion).

[0041] In a battery unit of one embodiment, the first fluid volume portion is defined by two planar components of the battery unit, and the weld lines around them between the two planar components seal the first fluid volume portion. The first fluid intermediate port is in fluid communication with the first fluid volume portion. There is no weld path around any port that is in fluid communication with the first fluid volume portion. One or both of the planar components may have a flanged outer peripheral feature, and the battery unit is sealed around the flanged outer peripheral feature by welding between the two planar components to form the first fluid volume portion. The two planar components abut (i.e., contact) each other around the flanged outer peripheral feature. The flanged outer peripheral feature in the first planar component of the planar components extends toward the other planar component (conversely if both components have a flanged outer peripheral feature).

[0042] Alternatively, when using a battery unit with a spacer, the weld line around the outer periphery of the battery unit may pass through a gasket or spacer disposed between the two planar components.

[0043] In a battery unit of one embodiment, the first fluid volume portion is defined by two planar components (plates) of the battery unit, and the weld line between the two planar components surrounds the second fluid intermediate port such that the second fluid intermediate port is not in fluid communication with the first fluid volume portion. The weld line surrounding the port and between the two planar components (e.g., a metal support plate and a separator plate) seals the port from fluid communication with the space between the two planar components or the (first) fluid volume portion defined by them. One or both of the planar components may have an annular feature surrounding the second fluid intermediate port and extending toward the other planar component, and the weld line is around the annular feature. The two planar components abut (i.e., contact) each other around the annular feature. The annular feature in the first planar component of the planar components extends toward the other planar component (conversely if both planar components have an annular feature), and thus the annular feature extends inwardly within the battery unit.

[0044] Alternatively, the weld line surrounding the port may pass through a gasket or spacer disposed between two planar components.

[0045] In one embodiment, each battery unit further comprises at least one second fluid intermediate port, the at least one second fluid intermediate port being disposed within or intermediate the lengths of one or more active battery chemical regions and in fluid communication with a second fluid volume of the battery unit. The second fluid intermediate ports of each battery unit are aligned to form at least one second fluid intermediate passage extending in the stack direction, and the stack is configured such that, at each second fluid volume, each second fluid flow path extends across one or more active battery chemical regions between at least one second fluid intermediate port and each corresponding opposing battery end.

[0046] The corresponding second fluid flow paths may extend in opposite directions across one or more active battery chemical regions between at least one second fluid intermediate port and each corresponding opposing battery end. As a result of the second fluid intermediate ports, the second fluid volume benefits from advantages similar to those described above for the first volume. The second fluid intermediate ports may be disposed intermediate the length and intermediate the width of the battery unit. One or more of the first fluid intermediate ports and the second fluid intermediate ports may be offset from the middle of the width or length of the battery unit and may be arranged symmetrically with respect to a middle line along the width or length of the battery unit. The second fluid intermediate port(s) are typically spaced apart from the first fluid port in a direction substantially parallel to the width of the battery unit.

[0047] In such a battery unit (having at least one second fluid intermediate port), the first fluid volume portion may be defined by two planar components, and the weld line around their outer periphery between the two planar components seals the first fluid volume portion, and the weld line between the two planar components surrounds the second fluid intermediate port. Thus, the first fluid intermediate port is in fluid communication with the first fluid volume portion, and the weld line surrounding the second fluid intermediate port seals the second fluid volume portion from the first fluid volume portion.

[0048] One or both of the planar components may have an annular feature surrounding the second fluid intermediate port and extending towards the other planar component, and the weld line is around the annular feature. One or both of the planar components may have a flanged outer peripheral feature, and the battery unit is sealed around the flanged outer peripheral feature by welding between the two planar components to form the first fluid volume portion. In this case, the two planar components abut (i.e., contact) each other around the annular feature and abut each other around the flanged outer peripheral feature. The annular feature and the flanged outer peripheral feature in the first planar component of the planar components extend towards the other planar component (and vice versa if both planar components have the annular feature and the flanged outer peripheral feature), and thus the annular feature extends inwards within the battery unit.

[0049] Alternatively, the weld line surrounding the second fluid intermediate port may pass through a gasket or spacer disposed between the two planar components.

[0050] The battery unit may comprise two planar components that define a first fluid volume therebetween, but the second fluid volume is defined between adjacent battery units. Each battery unit (either or both of the planar components) may comprise an annular feature surrounding each first fluid port (the first fluid intermediate port and, if present, the first fluid end port), the annular feature extending towards an adjacent battery unit and contacting the adjacent battery unit within the stack. The first fluid volume may be sealed from the second fluid volume by a weld line between adjacent battery units around the annular feature. The second fluid port (e.g., the second fluid intermediate port) is in fluid communication with the second fluid volume, and each second fluid port may comprise a raised port feature that surrounds the fluid port and enables fluid communication between the second fluid volume and a passage defined by the second fluid port. These raised port features are provided on either or both of the planar components and project away from the other planar component of the battery unit so as to project towards an adjacent battery unit.

[0051] Typically, the first fluid intermediate port is an inlet port. If present, the second fluid intermediate port is preferably an inlet port. The first fluid intermediate passage and / or the second fluid intermediate passage may comprise an inlet passage or an outlet passage. When used as an inlet passage (such that the intermediate port is a delivery port or an inlet port) to the first fluid volume and / or the second fluid volume (respectively), the use of the intermediate port as an inlet port aids in warming up the stack in terms of both warm-up speed, reduces temperature variations across the battery as hot fluid enters each battery unit near the center of the stack, and thus reduces the path length of heat conduction from the inlet to the outlet for a given battery length.

[0052] Each battery unit comprises two first fluid intermediate ports each in fluid communication with the first fluid volume and one second fluid intermediate port in fluid communication with the second fluid volume, and optionally, the second fluid intermediate port is preferably disposed between the two first fluid intermediate ports.

[0053] The flows of both fluid volume portions are preferably symmetric, leading to an improvement in heat and fluid distribution. The fluid intermediate ports may be aligned along a line in the middle of the length of the battery unit, and the line may be within or between one or more active battery chemical substance regions. The line may be substantially perpendicular to the length of the battery unit. Two first fluid intermediate ports (in fluid communication with the first fluid volume portion) may be equidistantly arranged (preferably in the width direction) from one second fluid intermediate port (in fluid communication with the second fluid volume portion).

[0054] Alternatively, there may be two second fluid intermediate ports with one first fluid intermediate port arranged therebetween. Again, this results in a symmetric fluid flow path.

[0055] Alternatively, for example, there may be a plurality of intermediate ports proportional to the width of the battery unit (the dimension perpendicular to the entire fluid flow path), and the plurality of intermediate ports may be arranged symmetrically with respect to the middle of the width of the battery unit. When both the first fluid intermediate port and the second fluid intermediate port are present, there may be a plurality of each of the first fluid intermediate port and the second fluid intermediate port such that the first fluid intermediate port is adjacent to the two second fluid intermediate ports and vice versa, and they may be alternately symmetric with respect to the middle of the width of the battery unit. The plurality of intermediate ports are arranged along a line in the middle between the ends of the battery unit (i.e., on both sides in the middle of the length of the battery unit and / or between the active battery chemical substance regions).

[0056] If there is at least one second fluid intermediate port, a first fluid end passage in fluid communication with the first fluid volume extending in the stack direction at or near each opposing stack end may be provided, which are internally manifolded passages defined by aligned first fluid end ports and second first fluid end ports within each battery unit, respectively. However, a second fluid end passage in fluid communication with the second fluid volume extending in the stack direction at or near each opposing stack end is provided, which are externally manifolded passages across each battery unit.

[0057] For each of the first fluid volume and the second fluid volume, the stack may be configured such that its intermediate and end fluid passages form inlet and outlet passages, or vice versa, within the stack to supply a specific fluid to the fluid volume of each battery unit during use. Therefore, the fluid flow path extends across one or more active battery chemical regions of each battery between both battery ends opposite its intermediate port. The end passages for one or both fluid types may be internally manifolded, but to maximize the active battery chemical surface area, a certain type of fluid end passage is preferably externally manifolded.

[0058] The aligned first fluid end ports and second first fluid end ports, and the two first fluid intermediate ports preferably form a diamond arrangement. The first fluid intermediate ports may be symmetrically arranged at the middle of the length of the battery unit towards the edges of the width of the battery unit, and the first fluid end ports are arranged at the middle of the width of the battery unit. The diamond arrangement of the ports is preferably for fuel ports, and the intermediate ports are preferably inlet ports to the first fluid volume, and the end ports are preferably outlet or discharge ports from the first fluid volume. In this case, the second fluid intermediate ports are for the oxidant and are preferably inlet ports to the second fluid volume.

[0059] Typically, the first fluid volume portion is a fuel volume portion and the second fluid volume portion is an oxidant volume portion. The pressure drop across the length of the active battery chemistry is typically more pronounced with the oxidant, and thus the gap between adjacent battery units is generally larger than the gap between the metal substrate and the separator plate within the battery unit. To define the second fluid volume portion in this way, it is preferred that the second fluid, which is manifolded externally, is the oxidant. This means that in this case, the first fluid volume portion for the fuel is housed or sealed within the battery unit and is in fluid communication with the first fluid intermediate passage and, if present, the first fluid end passage. Further, if the first fluid volume portion (enclosed by the battery unit) is configured for air, the gap between the metal substrate and the separator plate would have to be made larger, leading to the use of more material to form the larger gap and thus higher lamination costs.

[0060] In an alternative arrangement of the ports of the battery unit, there may be two pairs of first fluid end ports in a cross-shaped arrangement having a single first fluid intermediate port. The single first fluid intermediate port may be disposed midway between both the length axis and the width axis of the battery unit, and each of the first fluid end ports may be disposed towards a corner of the (rectangular or square) battery unit. In this case, there may be two second fluid intermediate ports with the first fluid intermediate port disposed therebetween. The second fluid may have end passages, and the second fluid end passages in fluid communication with the second fluid volume portion are provided to extend in the stack direction at or near each opposing stack end, and these are passages that are manifolded externally across each battery unit. In this arrangement, it is preferred that the first fluid is fuel and the second fluid is oxidant.

[0061] Ideally, one or more first fluid intermediate ports are arranged symmetrically within the battery unit with respect to one or both axes of the battery unit. The intermediate port(s) may be arranged towards the center of either or both the longitudinal axis and the width axis of the battery unit. The symmetrical arrangement of the intermediate ports promotes symmetrical flow into and out of the intermediate ports, thus resulting in a symmetrical fluid distribution and even temperature profile throughout the battery unit. An even temperature distribution throughout the battery unit, especially throughout the active battery chemical region(s), promotes uniform degradation of the active battery chemicals over its lifetime.

[0062] If present, one or more second fluid intermediate port(s) are preferably arranged symmetrically within the battery unit with respect to one or two axes of the battery unit.

[0063] In one arrangement, there may be two first fluid intermediate ports and two second fluid intermediate ports. The two first fluid intermediate ports and the two second fluid intermediate ports may each be arranged on either side of a line midway along the length of the battery unit, with the first fluid intermediate port and the second fluid intermediate port each being arranged towards each edge of the width of the battery unit. Thus, there may be multiple pairs of intermediate ports, with each pair having a first fluid intermediate port and a second fluid intermediate port, and each pair being arranged towards each edge of the width of the battery unit. The center of each pair is midway along the length of the battery unit. Preferably, in the first pair, the first fluid intermediate port is directed towards the first end of the length of the battery unit and the second fluid intermediate port is directed towards the second end of the length of the battery unit (the second end being opposite the first end), and in the second pair, the first fluid intermediate port is directed towards the second end of the length of the battery unit and the second fluid intermediate port is directed towards the first end of the length of the battery unit.

[0064] One or more active battery chemical regions are preferably wound around at least one of any intermediate or end ports provided in the battery unit.

[0065] The fluid ports around which the active battery chemical region is wound may include at least one first fluid intermediate port, at least one second fluid intermediate port, and one or more of any battery end ports present. "Wound" means that the active battery chemical region at least partially surrounds the port (e.g., more than 90°, more than 180°, or about 360° of the port). The shape of the edge of the active region may match or reflect the shape of the edge of the port such that the active region at least partially surrounds the port. If the port is circular, the edge of the wound active battery chemical region takes the form of an arc. The edge of the active region may be equidistant from the port around the perimeter of the wound region. Alternatively or additionally, the wound edge of the active region may not be equidistant from the port, and in particular, the radius defining the edge of the active region may increase with the distance from the port around which the active region is wound.

[0066] This winding of the active battery chemical region maximizes the area within the battery unit available to the active battery chemical region, thereby maximizing the power density of the stack. In other words, when viewing the battery unit along its length from one battery end to the other opposing battery end, a particular position along that length simultaneously occupied by both the port and the battery chemical (since the chemical extends around the intermediate or end port) will achieve a higher utilization rate than a battery having the chemical confined only to regions beyond the region where the port is located.

[0067] If the active battery chemical region is a single region, the active region may be wound around the entire perimeter of the intermediate port. The active battery chemical region may be spaced apart from the port to provide space for gaskets and / or molded port features. A barrier layer (e.g., an extended electrolyte layer) may extend under the gasket, and the gasket may contact the barrier (e.g., electrolyte) layer to ensure that the active battery chemical is tightly wound around the port.

[0068] Instead of or in addition to being wound, one or more ports may be elongated in the width direction of the battery unit. For example, one or more ports may be rectangular, thereby allowing for a rectangular wrap around the perimeter of the rectangular port. In this case, the proportion of the increased battery unit area that includes the active battery chemical substance region can be provided without necessarily winding around the active battery chemical substance region, so the intermediate port may preferably be rectangular. The same applies to the end ports.

[0069] In a certain battery unit, one of the first fluid volume portion or the second fluid volume portion is defined by a planar component having an elongated formed feature, and the formed shape feature extends at least partially around the outer periphery of the active battery chemical substance region so as to define a fluid flow path within that region.

[0070] The planar component is preferably a metal component. The planar component may be an interconnecting plate, a current collector plate, a separator plate, a battery chemical substance support substrate, etc. The elongated feature functions to direct and hold fluid in one or both of the fluid volume portions (in some cases plural). That is, the elongated feature significantly reduces the bypass of air around the side surface of the battery unit (the bypass of air around the side surface of the battery unit cannot participate in the chemical reaction in the active battery chemical substance region).

[0071] The elongated formed feature may constitute features of a planar component that form a protruding rib on one side surface of the component and a channel on the other side surface of the component. Such a protruding rib on one side surface of the component defines a flow path for the first fluid or the second fluid within the active battery chemical substance region, and on the other side surface, it extends as a channel that promotes a flow path along the outer periphery of that region, thereby being able to deliver fluid towards the distal edge of the region. In the planar component, the elongated formed feature that constitutes the features of the protruding rib on one side surface of the component and the channel on the other side surface of the component may be a pressure-formed or formed feature.

[0072] The rib protrudes into one fluid volume and functions to contain therein that fluid which is one of fuel or oxidant (otherwise passing around the side of the battery unit). The rib may form a depression in the second fluid volume and form a supply channel for supplying the second fluid which is the other of fuel and oxidant.

[0073] The rib may be a molded or pressure-molded feature, in which case the rib forms a depression in the second fluid volume and forms a supply channel for supplying the second fluid which is the other of fuel and oxidant. The rib may be a feature molded or pressure-molded on an interconnecting plate or separator plate and protrudes towards adjacent battery units in the stack.

[0074] Typically, the rib or elongate feature contacts the electrolyte or cathode layer in the active battery chemical region beyond the region of the adjacent battery. Thus, the fluid volume is formed between the interconnecting plate or separator plate and the active battery chemical region of the adjacent battery unit. The protruding side of the rib or elongate feature functions to contain the fluid within the fluid volume formed between the interconnecting plate or separator plate and the active battery chemical region of the adjacent battery unit and prevent the fluid from exiting the battery to the side of the battery unit.

[0075] The rib or elongate feature protrudes into a fluid volume having a passage manifolded externally beyond the ends of each battery unit, in which case the rib preferably functions to contain and direct that fluid between the respective ends of the battery unit and the fluid intermediate port. The rib or elongate feature preferably protrudes into the oxidant volume and the opposite side of the rib or elongate feature forms a supply channel for fuel within the opposite fluid volume.

[0076] The rib or elongated feature may comprise a pair of such ribs or elongated features aligned with the edge of the porous region or the active cell chemical region in the stack. Each rib or elongated feature is respectively disposed at the edge of the porous region or the active cell chemical region, such that it is substantially aligned with the edge of the battery unit.

[0077] Each rib or elongated feature may be continuous along the length of the battery unit. Alternatively, each rib or elongated feature may be discontinuous, and this discontinuity is due to a fluid intermediate port. The discontinuous ends of the rib or elongated feature may be close to a gasket or a molded port feature, and the gasket or molded port feature forms part of an intermediate fluid passage such that the rib or elongated feature and the gasket or molded port feature cooperate to contain fluid within a fluid volume.

[0078] Discontinuous ribs or elongated features may further curve towards the center of the battery unit at the ends of the ribs or elongated features that are close to the intermediate port. For example, the rib or elongated feature may curve so as to match the curve at the end of the active battery chemical region, for example, a curve wrapped around the port or a curve matching the active battery chemical. In this case, the rib or elongated feature is sized to supply fluid (e.g., fuel) to the corner of the active battery chemical region at the end of the battery unit on the side that is the channel. This is the case where the battery unit comprises at least two first fluid intermediate ports (arranged towards opposite edges of the battery unit) with at least a second fluid intermediate port disposed therebetween, the intermediate ports are aligned in the middle of the length of the battery unit, and there are a first fluid end port and a second first fluid end port respectively disposed near each opposite battery end or thereabouts (i.e., similar or the same as the "diamond" configuration described herein). In such a battery unit, the discontinuous rib may curve towards the second fluid intermediate port in the region of its end that is close to the first fluid intermediate port, and the end of the rib is close to the gasket within the second fluid volume. In this case, the rib may form a protrusion in the second fluid volume and a depression in the first fluid volume. As a result, the curved rib prevents the bypass of the second fluid from the second fluid volume while providing a fluid supply channel for the first fluid, improving the supply to the region near the corner of the battery unit in the battery chemical region, thereby preventing starvation in that region. This has been shown to significantly improve the uniformity of fuel supply to the periphery of the region beyond expectation.

[0079] If there are a plurality of intermediate ports for one of the fluid volume parts, in order to ensure that the fluid is directed only to a specific part of the active battery chemical substance region, for example, rib splitting extending across the battery from a specific intermediate port or shaping of a 3D shape (as a soft barrier) or splitting by welding (as a hard barrier or absolute barrier) can be used. If there are a plurality of chemical substance regions, by using such splitting means, while the active battery chemical substance region has a dedicated intermediate port supply passage that supplies fluid only to a specific chemical substance region (for example, the region in half of the battery), it can be ensured that the other intermediate ports have dedicated supply passages that supply fluid only to the remaining active battery chemical substance regions. This can have advantages, but if the fluid supply in the dedicated fluid passage fails, there is a risk that only the related split region will run out of fuel, leading to a failure of a part of the battery / stack.

[0080] In one embodiment, the battery unit comprises a separator plate, and a metal support plate holding an active battery chemical substance region (which may be plural) provided on a porous region on a first side surface, the separator plate and the metal support plate overlap each other to form a battery unit, at least one of the separator plate and the metal support plate comprises a flanged outer peripheral feature formed by press-forming the plate into a concave shape, the separator plate and the metal support plate are directly adjacent at the flanged outer peripheral feature and form a first fluid volume part therebetween, optionally by welding, at least one fluid port is provided on each of the separator plate and the metal support plate, and these are aligned to form a first fluid passage within the flanged outer peripheral feature, and each port is either a first fluid intermediate port and / or a first fluid end port and communicates with the first fluid volume part, At least one of the separator plate and the metal support plate has a formed port feature formed around at least one of its fluid ports by pressure forming, the formed port feature extending towards the other plate, elements of the formed port feature being spaced apart from each other to define a fluid passage from the port between the elements and allowing fluid to pass from at least one first fluid port to a first fluid volume.

[0081] Instead of the metal support plate, the spacer, and the separator plate, the battery unit may comprise only two layers / components, namely only the metal support plate and the separator plate, but still operate substantially in the same way in the end, and the output per square centimeter of the electrochemically active layer per battery unit is substantially the same. This simplifies the number of components that require supply and processing (e.g., coating), not only making assembly easier, but also immediately reducing the amount of material required, and thus reducing both the material cost and weight of each fuel cell unit.

[0082] The concave shape can give the appearance of a tray with an edge to the associated plate, corresponding to a convex outer shape (relative to the outside of the fuel cell unit) and a usually planar bottom, such that the concave surface defines a fluid volume (e.g., a part thereof) of the assembled battery unit. In this concave shape, the flanged outer peripheral feature extends from the plane of the original sheet of the separator plate and / or the metal support plate towards the other corresponding opposing surface of the separator plate and the metal support plate. Thus, the fluid volume is bounded by the formed flanged outer peripheral features, which are formed by pressure forming, for example, using die pressing, hydroforming, or punching processes. These are a simple process already being done to form a central protrusion within the fluid volume to support and electrically connect adjacent fuel cells through the electrochemically active layer, as can also be seen in prior art separator plates. Such central internal and external protrusions may also be pressure formed from the original sheet for the separator plate either before or after, but more preferably simultaneously with, the flanged outer peripheral features and the formed features.

[0083] In some embodiments, the porous region is formed by holes, typically laser drilled, in the metal support plate.

[0084] In some embodiments, the (active) fuel cell chemical layer is in the form of an electrochemically active layer comprising an anode, an electrolyte, and a cathode, formed (e.g., coated or deposited) on the metal support plate over the porous region provided within the metal support plate in such embodiments. The configuration using this (non-self-standing thin) chemical layer provided directly on the metal support plate requires a minimal number of components. In this way, the metal support plate serves the dual function of supporting the fuel chemicals and defining (together with the separator) the fluid volume. Further, it will be appreciated that both the metal support plate and the separator are components that are exposed to a severe dual atmospheric environment, as both have surfaces exposed to the oxidant and surfaces exposed to the fuel.

[0085] In other embodiments, the porous region is provided in a separate plate (e.g., a metal foil) on which the fuel cell chemical layer is formed (e.g., coated or deposited), and the separate plate (supporting the fuel cell chemical layer) is provided on a window (e.g., a frame) of the metal support plate.

[0086] There may be multiple regions of the fuel cell chemical layer. For example, there may be multiple regions of small holes in the metal support plate covered by separate corresponding electrochemically active layers. Alternatively, there may be multiple windows in the metal support plate and the multiple separate plates, and there (on which) the active cell (fuel cell) chemical layers are arranged on top of the windows to be formed.

[0087] The said or each separate plate may be welded to the metal support plate so as to cover the window of the metal support plate.

[0088] In the stack, at least one further fluid port is provided in each of the separator plate and the metal support plate, which are aligned to form a second fluid passage within the flanged outer peripheral feature, and each port is either a second fluid intermediate port and / or a second fluid end port and communicates with a second fluid volume at a second side of the metal support plate. The second fluid passage is sealed from the first fluid volume, optionally by providing a weld around the second fluid port. The port further optionally comprises an annular flange formed by pressure molding an annular region around the port in at least one of the separator plate and the metal support plate.

[0089] In a preferred embodiment, the first fluid flow path and the second fluid flow path are in a co-flow arrangement across the active battery chemical region. The fluid may flow in a co-flow arrangement where both the first fluid flow path and the second fluid flow path flow from respective ends of the battery unit towards the center of the battery unit, or vice versa. That is, from an end fluid passage to an intermediate fluid passage, or vice versa.

[0090] Alternatively, the fluid may be in a counter-flow arrangement where the first fluid flow path flows from respective ends of the battery unit towards the center of the battery unit, and the second fluid flow path flows from the center of the battery unit towards respective ends of the battery unit, or vice versa. That is, the first fluid flow path is from an intermediate passage to an end passage, the second fluid flow path is from an end fluid passage to an intermediate passage, or vice versa.

[0091] Alternatively, the fluid may be in a co-counter-flow arrangement where the first fluid flow path flows from respective ends of the battery unit towards the center (or vice versa), and the second fluid flow path flows from one end of the battery unit towards the opposite end of the battery unit. That is, the first fluid flow path is from an intermediate passage to an end passage (or vice versa), and the second fluid flow path is from an end fluid passage at one end of the battery to an end passage at the opposite end of the battery.

[0092] Alternatively, the fluid may be such that the first fluid flow path is from each end of the battery unit to the center of the battery unit (or vice versa), the second fluid flow path is substantially perpendicular to the first fluid flow path, and the second fluid flow path is arranged orthogonally from one long side of the battery unit to the opposite long side of the battery unit. That is, the first fluid flow path is from the intermediate passage to the end passage (or vice versa), and the second fluid flow path travels to and from the internal or external side fluid passages respectively arranged at or near the length of each pair of opposing batteries and manifolded.

[0093] The co - flow arrangement is preferred because, in contrast to the counter - flow where the hottest part of the battery unit is towards the center of the active battery chemical region (mid - way between the intermediate port and the end of the battery unit), the hottest battery unit region is towards the end of the battery unit. Thus, in counter - flow, the measured temperature of the discharged fluid better reflects the highest temperature of the stack, which is an important parameter since excessive heat can lead to battery unit failure. Further, in counter - flow, the highest temperature is typically higher than in co - flow (all other parameters being the same), so a larger flow rate is required for cooling (typically using the oxidant flow) in counter - flow arrangement, and thus the parasitic losses due to blowers or pumps increase more than in co - flow arrangement.

[0094] In an alternative arrangement, there may be two first fluid intermediate ports and two second fluid intermediate ports. The two first fluid intermediate ports and the two second fluid intermediate ports are respectively arranged on both sides in the middle of the length of the battery unit, and the first fluid intermediate port and the second fluid intermediate port are respectively arranged towards each edge of the width of the battery unit. Thus, there are multiple pairs of intermediate ports, and each pair of intermediate ports has a first fluid intermediate port and a second fluid intermediate port, and each pair is towards each edge of the width of the battery unit. The center of each pair is in the middle of the length of the battery unit. In the first pair, the first fluid intermediate port is arranged from the middle towards the first end of the battery unit, and in the second pair, the first fluid port is arranged from the middle towards the second end of the battery unit, and the first end is on the opposite side of the second end.

[0095] In an alternative configuration, there may be one first fluid intermediate port and one second fluid intermediate port. The first fluid intermediate port faces a first edge of the width of the battery unit, and a pair of first fluid end ports are arranged one by one at each end of the length of the battery unit, facing a second edge of the width of the battery unit. The second fluid intermediate port is arranged facing the second edge of the width of the battery unit, and a pair of second fluid end ports are arranged one by one at each end of the length of the battery unit, facing the first edge of the width of the battery unit. Therefore, the first fluid ports are arranged in a V shape, and the second fluid ports are arranged in a V shape.

[0096] In a preferred arrangement, the first fluid is fuel, the second fluid is an oxidant, the stack comprises a rectangular (including elongated and square) planar electrochemical battery unit, each battery unit is arranged in the middle of the length within or between one or more active battery chemical substance regions, and comprises two first fluid intermediate ports in fluid communication with the first fluid volume of the battery unit. The stack is configured such that in each first fluid volume, the first fluid flow path extends (in opposite directions) across one or more active battery chemical substance regions between at least one first fluid intermediate port and each corresponding opposing battery end. In this arrangement, the stack may further comprise one second fluid intermediate port, the one second fluid intermediate port is arranged in the middle of the length within or between one or more active battery chemical substance regions in fluid communication with the second fluid volume of the battery unit, the second fluid intermediate port is arranged between the two first fluid intermediate ports, and the stack is configured such that in each second fluid volume, each second fluid flow path extends (in opposite directions) across one or more active battery chemical substance regions between at least one second fluid intermediate port and each corresponding opposing battery end.

[0097] In this arrangement, the stack may further include a first fluid end passage that is in fluid communication with a first fluid volume portion that extends in the stack direction at or near each opposing stack end and in the middle of the width of the battery unit. These are passages that are manifolded internally and are defined by a first fluid end port and a second first fluid end port that are aligned within each battery unit. The stack may include a second fluid end passage that is in fluid communication with a second fluid volume portion that extends in the stack direction at or near each opposing stack end. These are passages that are manifolded externally across each battery unit.

[0098] The first fluid intermediate ports of each battery unit are preferably aligned to form at least one first fluid intermediate passage that extends in the stack direction. The second fluid intermediate ports of each battery unit are preferably aligned to form at least one second fluid intermediate passage that extends in the stack direction.

[0099] The battery unit may be a rectangular (e.g., elongated or square) fuel or electrolyte battery unit having at least one fuel intermediate port and one oxidant intermediate port. The intermediate port may be disposed in the middle of the length of the battery unit so as to divide the active battery region into two equal parts, with at least one pair of fuel end ports being disposed one each at each end of the length of the battery unit, and / or at least one pair of oxidant end ports being disposed one each at each end of the length of the battery unit, and each flow path extending in the opposite direction from the respective intermediate port to the respective corresponding opposing end port, or to the respective battery unit end if manifolded externally, such that the battery is configured to have both a fuel flow path and an oxidant flow path. The battery unit may comprise two planar component parts, and the ports are provided to pass through each of the planar component parts. The two planar component parts define or enclose a first fluid volume therebetween. One of the intermediate ports may comprise a raised port feature in the form of a ring, and the raised port feature projects from one or both of the planar component parts towards the other planar component part (i.e., within and through the first fluid volume) such that the raised port feature on one planar component part projects or contacts the other planar component part. A weld line may be provided around the raised port feature that seals the port from fluid communication with the first fluid volume. Ports that are in fluid communication with the first fluid volume (e.g., a first fluid intermediate port) may comprise a raised port feature around the port that extends into the first fluid volume from one or both of the planar component parts and contacts the other planar component part, which functions to allow fluid communication between the port and the fluid volume while resisting stack compression forces. These ports may also comprise an annular raised feature that extends away from the other planar component part within the battery unit on one or both of the planar component parts, and these raised features are configured to contact an adjacent battery unit within the stack, sealing the port (using a weld line around the raised feature) and preventing fluid communication between the port and the fluid volume defined between the port and the adjacent battery unit.

[0100] The battery stack may be an electrochemical battery stack including a plurality of planar batteries stacked on top of each other. Each battery has a length greater than its width and includes at least one battery intermediate port disposed in the middle of the stack length, and at least a first battery end port and a second battery end port respectively disposed at or near each opposite end of the battery length. It includes at least one active battery chemical region with an electrolyte interposed between the air electrode and the fuel electrode, and includes an air fluid volume and a fuel fluid volume respectively communicating with each of the air electrode and the fuel electrode. Each battery intermediate port is aligned to form an internal fluid intermediate passage extending in the stack direction and may be connected to either each air fluid volume or each fuel fluid volume of the battery. Each first battery end port and second battery end port may be aligned to form a corresponding first internal fluid end passage and second internal fluid end passage, each extending in the stack direction and connected to the same fluid volume. The intermediate passage and the end passage may form an inlet passage and an outlet passage, or vice versa, with respect to the fluid volume so as to define opposing flow paths within the volume extending across each battery between each battery intermediate port and its respective corresponding end port.

[0101] In one example, the battery unit includes a unique molding feature (e.g., a flanged outer peripheral feature) that creates a fluid volume within the battery unit. The battery unit may have a flanged outer peripheral feature, and the battery unit may be sealed around the flanged outer peripheral feature to form a first fluid volume. The sealing may use welding around the flanged outer peripheral feature. The welding(s) may also be used around the intermediate port(s) and end port(s) to seal the first fluid volume from the second fluid volume. The battery may include a metal substrate and a separator plate, at least one of which has a flanged outer peripheral feature. This eliminates the need for spacers, reducing the number of components and thus waste of materials. This also conveniently allows for electrical connection of two metal plates.

[0102] The fluid port(s) are provided as openings passing through each of the battery units (i.e., through each of the metal substrate and the separator plate of each battery unit), and each fluid port is aligned with each other in the stacking direction to form a fluid passage communicating with each fluid volume portion.

[0103] The battery unit (i.e., at least one of the metal substrate and the separator plate) has a molded port feature formed around the port extending inwardly within the battery unit, and the elements of the molded port feature are horizontally spaced from each other, defining a fluid passage from the port between the elements, and preferably allowing fluid to pass from the port to the fluid volume portion surrounded by the battery unit. The molded port feature is preferably also formed by pressure molding.

[0104] At least one of the metal substrate and the separator plate may have a molded port feature formed around the port extending outwardly away from the fluid volume portion surrounded by the battery unit. When a plurality of such battery units are stacked adjacent to each other, such a feature can serve to horizontally position a sealing gasket provided between the battery units, or such a feature can form a hard stop that limits the compression of a gasket provided between or within the battery units in contact with the adjacent plates (metal substrate and separator plate), or may form a surface for forming a seal in situ from a sealing paste or the like. In a battery stack, since the metal substrate may be electrically connected to the adjacent separator plate, such a molded port feature can be conveniently welded to the molded port feature of the adjacent metal substrate or separator plate, providing both electrical connection and port / manifold sealing.

[0105] The support structure may be provided within a fluid volume surrounded by the battery unit to help maintain the spacing between the metal substrate and the separator plate. The support structure may be a permeable support structure and need only be exposed to one fluid environment that is the same fluid environment across its surface area. This reduces the thermal and chemical requirements of the support structure. The innermost electrode (closest to the support metal substrate) may be electrically connected by the metal substrate, and the outermost electrode may be electrically connected by the current collector structure. The current collector structure may be a permeable support structure and need only be exposed to one fluid environment that is the same fluid environment across its surface area. This reduces the thermal and chemical requirements of the current collector structure.

[0106] Alternatively, the separator plate may have dimples formed or pressure-molded therein that extend towards or away from the active battery chemical region of the battery unit. These dimples maintain the spacing between the metal substrate and the separator plate and assist in collecting current from the active battery chemical region.

[0107] The support structure or separator plate facing the active battery chemical region within the fluid volume surrounded by the battery unit may be provided with a catalyst, for example, to promote internal reforming if the fluid volume is a fuel volume. If no support structure is provided within the fluid volume, for example, if the fluid volume is a fuel volume, such a catalyst may be provided on the surface of the metal substrate.

[0108] Here, these and other features of the present invention will be described in more detail by way of various embodiments and, by way of mere example, with reference to the accompanying drawings (the drawings are not to scale and the height dimensions are exaggerated in general for clarity).

Brief Description of the Drawings

[0109]

Figure 1

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Figure 4b

Figure 4c

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Embodiments for Carrying Out the Invention

[0110] FIG. 2a shows a first example of a battery unit 200 which is a coupon (i.e., three component layers) with a spacer, similar to a prior art battery.

[0111] The battery unit 200 has a substrate in the form of a rectangular metal support plate 205, on which two separate active battery chemical regions, i.e., electrochemically active layers 210, are deposited. The two electrochemically active layers 210 are arranged side by side.

[0112] Figure 2b is a longitudinal side cross-sectional view along line A-A of the battery unit 200 in Figure 2a. Figure 2b shows the electrochemically active layer 210 in more detail. Each battery unit 200 includes battery chemical layers 211, 212, 213 deposited or coated on a metal support plate 205, forming the electrochemically active layer 210. The anode layer 213, the electrolyte layer 212, and the cathode layer 211 are continuously laid on the porous region 214. However, depending on the battery arrangement, the order may be reversed (such that the cathode layer is closest to the substrate).

[0113] The metal support plate 205 is a metal (e.g., ferritic stainless steel) foil. The porous region 214 includes an array of through-holes formed by perforation (or other means, such as etching) that extends from the first side 225 of the metal support plate 205 to the opposite side (the second side 226) and is surrounded by a non-porous region.

[0114] The anode layer 213, the electrolyte layer 212, and the cathode layer 211 may be formed by vapor deposition on the metal substrate 205, such as chemical vapor deposition, electrostatic coating, spray deposition, spin-on deposition, powder deposition, etc. This process may be a two-step process that performs sintering or other processing after the deposition of the powder or granular material to form each of the layers of the solid oxide battery. Each layer is a thin layer that is not self-standing, i.e., the metal substrate is required to provide support to the solid oxide chemical layer. Other barrier layers, such as an extended electrolyte layer 215, may also be provided.

[0115] The electrochemically active layer 210 may be formed directly on the metal substrate 205, or may be formed on a separate porous metal substrate attached to a substrate with a window frame. In the latter case, the two separate electrochemically active layers shown in Figure 2 may be formed on two separate porous metal supports. However, this requires more components and more manufacturing steps.

[0116] Returning to FIG. 2a, there are two first fluid intermediate ports 230a, 230b for the delivery or removal of a first fluid to or from the first fluid volume, and a single second fluid intermediate port 235 for the delivery or removal of a second fluid to or from the second fluid volume. The first fluid intermediate ports 230a, 230b and the second fluid intermediate port 235 are disposed between two electrochemically active layers (or regions) 210 and are in the middle of the length of the battery unit.

[0117] Since the second fluid intermediate port 235 is disposed between two electrochemically active layers 210, it is disposed substantially centrally along the first (long) axis of the metal support plate 205. The single second fluid intermediate port 235 is further disposed between the two first fluid intermediate ports 230a, 230b, so it is disposed substantially centrally along the second (short) axis of the metal support plate 205. Thus, the second fluid intermediate port 235 is disposed substantially centrally within the metal support plate 205.

[0118] The first fluid intermediate ports 230a, 230b are disposed between two electrochemically active layers 210 that are equidistant from the two battery ends, so they are disposed substantially centrally along the first (long) axis of the metal support plate 205. The first fluid intermediate ports 230a, 230b are disposed on both sides of the second fluid intermediate port 235 away from the center of the second (short) axis, with the first fluid intermediate port 230a disposed towards the first (long) edge of the metal support plate 205 and the first fluid intermediate port 230b disposed towards the second (long) edge of the metal support plate 205.

[0119] Sufficient distance is provided between the intermediate ports 230a, 230b, 235 and between the intermediate ports 230a, 230b, 235 and the electrochemically active layers 210, enabling the placement of gaskets or molded port features around the ports. However, the gasket may contact and rest on a barrier layer (e.g., an extended electrolyte layer (not shown) extending beyond the electrochemically active layer 210).

[0120] The battery unit 200 further includes a pair of first fluid end ports 240a, 240b respectively arranged toward each end of the first (long) axis of the battery unit 200. The first fluid end ports are for the delivery or removal of the first fluid from the battery unit. The first fluid end ports 240a, 240b are closer to the ends of the first (long) axis of the battery unit 200 than the electrochemically active layer 210. For this reason, the ports 230, 240 for the first fluid are arranged in a rhombus shape.

[0121] The external manifold 245 represents the volume between the end of the battery unit 200 (i.e., the end of the metal support plate 205) and the inner edge of the housing in which a stack including a plurality of battery units 200 is arranged. The second fluid may be delivered to the battery unit 200 by the external manifold 245 or removed from the battery unit 200.

[0122] A part of the dimensions of the electrochemically active layer 210 and the battery unit range is further shown in FIG. 2a. Each electrochemically active layer is characterized by a minimum length x1 across the electrochemically active layer between the edge of the electrochemically active layer close to the intermediate port(s) and the opposite edge of the electrochemically active layer close to the end port. The minimum length x1 may be generally parallel to two edges of the electrochemically active layer or / and generally perpendicular to the other two edges of the electrochemically active layer. The length x1 is parallel to the main components of the fluid flow path between the intermediate port and the end of the battery unit (see also FIG. 4). Each electrochemically active layer is further characterized by a minimum width y1 across the electrochemically active layer, and this width is perpendicular to the length x1 and the main components of the fluid flow path. Both the length x1 and the width y1 define the aspect ratio of the electrochemically active layer as aspect ratio = x1 / y1. In one example, the aspect ratio is 1.2 or less.

[0123] The battery unit is characterized by its length x2 that is generally parallel to the main components of the fluid flow path (i.e., parallel to the line from the intermediate port 235 to the end of the battery unit). The battery unit is characterized by its width y2 that is generally perpendicular to the main components of the fluid flow path (i.e., parallel to the line from the intermediate port 235 to the end of the battery unit). In one example, the ratio x2 / y2 is 2.4 or less.

[0124] Figure 2b is a side cross-sectional view along line A-A of the battery unit 200 of Figure 2a. The battery unit 200 is a coupon, i.e., a repeating unit, that includes a metal support plate 205 on which an electrochemically active layer 210 is deposited or coated, and a separator plate 255 spaced from a second side of the metal support plate 205 (i.e., the side not holding the electrochemically active layer 210) by a spacer or gasket 260, whereby the coupon has an enclosed first fluid volume 280. The spacer or gasket 260 may be a framelike component similar to the prior art spacer plate 13 of Figure 1. The separation is also maintained by a formed port feature or gasket 261. When the formed port feature or gasket 261 is a formed port feature, this is a continuous raised ring that is welded or otherwise sealed (e.g., using a gasket or sealing paste) to seal the passageway. The formed port feature is further described with respect to Figure 3. The spacer or gasket 260 and the formed port feature or gasket 261 seal a first fluid (in a first fluid passageway and supplied to the first fluid volume 280 by first fluid ports 240a, 240b) from a second fluid (in a second fluid passageway and supplied to a second fluid volume 285 by a second fluid port 235), thereby preventing intermixing. This sealing may be achieved by welding or brazing through the coupon (i.e., through all of the metal support plate 205, spacers or gaskets 260 and 261, and separator plate 255 - such weld lines are similar to those shown in the variant of Figure 2d described below). See also Figure 4b below, which shows a gasket 262 around the end ports 240a, 240b in the second fluid volume 285 that seals the first fluid end passages 240a, 240b.

[0125] The fluid passage for the first fluid is formed by the first fluid port of the metal support plate 205, the corresponding hole through the separator plate 255, and the associated gasket or separator, i.e., the first fluid intermediate passage is formed by the first fluid intermediate port 230a, the corresponding hole through the separator plate 255, and the associated gasket or separator. The second fluid intermediate passage is formed by the second fluid intermediate port 235, the corresponding hole through the separator plate 255, and the associated gasket or separator 261. The first fluid end passage is formed within the region of the metal support plate 205 by the first fluid end port 240a, the corresponding hole through the separator plate 255, and the associated gasket or separator 260, and gasket 262 (FIG. 4b).

[0126] Spacers or gaskets 260 and 261 may be conductive, thereby providing an electrical connection between the metal support plate 205 and the separator plate 255 of the coupon or repeating unit. The conductivity may be improved by welding or brazing through the coupon.

[0127] The separation between the metal support plate 205 and the separator plate 255 defines the first fluid volume 280. In the arrangement shown in FIG. 2b where the anode layer is closest to the metal support plate 205, the first fluid volume is the fuel volume and the second volume is the oxidant volume (when operated in the SOFC mode).

[0128] The separation between the metal support plate 205 and the separator plate 255 can also be maintained by the support structure 265. The elements of the support structure 265 may be integral with the separator plate 255 (which is corrugated with press-forming features such as channels or dimples, or a pressed interconnector / bipolar plate is well-known in the art), and are shown as a plurality of domes, but may have other cross-sectional shapes such as pyramids, flat-top pyramids, cones, domes or bumps. The elements of the integral support structure 265 project from the separator plate 255 towards the coupon metal support plate 205 and contact the second side of the metal support plate 205 (the side on which the electrochemically active layer 210 is not deposited or coated). Alternatively, the support structure 265 may be a separate component, in which case it may include a mesh, expanded metal, or a combination thereof.

[0129] The support structure 265 may be a conductive support structure that functions to electrically connect the metal support plate 205 and the separator plate 255 to each other, thereby eliminating the need to electrically connect the metal support plate 205 and the separator plate 255 to each other using spacers or gaskets 260 and 261.

[0130] The integral second support structure 266 projects from the separator plate 255 so as to be away from the coupon metal support plate 205. The elements of the support structure 266 are shown as a plurality of domes, but may have other cross-sectional shapes such as pyramids, flat-top pyramids, cones, domes or bumps. Alternatively, the second support structure 266 may be a separate component from the separator plate 255, in which case it may include a mesh, expanded metal, or a combination thereof.

[0131] The second support structure 266 is typically a conductive support structure for enabling interconnection between adjacent coupons.

[0132] The integral support structure 265 and the support structure 266 may be formed on the separator plate 255 by pressure molding or molding the support structure 265 in a first direction and the support structure 266 in a second direction. The first direction is towards the second side of the metal support plate 205 (the side on which the electrochemically active layer 210 is not deposited or coated), and the second direction is opposite to the first direction, that is, the second direction is towards the electrochemically active layer 210 of the adjacent coupon. The molding or pressure molding process means that there is a depression (not shown) on the opposite side of the separator plate 255 with respect to the protrusion that is the support structure 265 or the second support structure 266.

[0133] Figure 2c shows a cross-sectional view of the battery unit 200 of Figure 2a taken along line B-B of Figure 2a. Thus, the cross-sectional view of Figure 2c is perpendicular to that shown in Figure 2b. However, an additional battery unit 200b is only shown in this figure to show how the battery units contact each other in the stack direction.

[0134] A pair of ribs 270a, 270b can be seen in Figure 2c. The ribs 270a, 270b are elongated protrusions that extend away from the separator plate 255 and from the metal support plate 205 of the battery unit or coupon 200 (i.e., towards the electrochemically active layer 210 of the adjacent battery unit), and thus the ribs protrude in the same direction as the second support structure 266. The ribs 270a, 270b are shown as having a pyramidal cross-section, but may have other cross-sectional shapes such as a dome, and may have a flat top or a rounded top. In contrast to the support structure 265 and the second support structure 266, the ribs are elongated. The ribs are elongated along the long axis direction of the battery unit 200 (in and out of the plane of Figure 2c) and are sized and arranged to contact the electrochemically active layer of the adjacent battery unit or coupon 200 (further described with reference to Figure 4).

[0135] The rib 270 is integral with the separator plate 255 and is formed by pressure - molding or molding the separator plate 255. Thus, the rib is a protrusion away from the metal support plate 205 and is also a channel on the side surface of the separator plate 255 facing the metal support plate 205. For this purpose, importantly, the rib forms both a channel within the first fluid volume portion 280 and a protrusion into the second fluid volume portion (further described with reference to FIG. 4).

[0136] The distal end, i.e., the peak, of the rib 270 of the first battery unit 200a is configured to contact the electrochemically active layer 210 of the adjacent battery unit 200b, contacting the edge or near the edge of the electrochemically active layer 210. When the rib contacts the cathode layer 211, the rib functions (together with the conductive second support structure 266) to collect current from the battery unit. Alternatively, the rib 270 may contact only the electrolyte layer 212 (since the cathode layer 211 typically has a smaller extent than the electrolyte layer 212). Since the rib 270 contacts the electrochemically active layer 210, there is no need to deposit (or provide) a non - conductive coating that would be required if the rib contacted the metal support plate 205.

[0137] Figures 2d - 2f show alternative battery units or coupons 201a, 201b comprising only two component layers, i.e., plates, i.e., the metal support plate 205 and the separator plate 255. Any spacer plate is omitted and the first fluid volume portion 280 (e.g., fuel volume portion) is instead created by the use of flange features and molding port features as described below.

[0138] FIG. 2d is a plan view, and FIGS. 2e and 2f are cross-sectional views of battery units (coupons) 201a, 201b without stacked spacers. Similar to FIGS. 2b and 2c, each of battery units 201a, 201b includes a metal support plate 205 on which an electrochemically active layer 210 is deposited or coated, a separator plate 255, and a support structure 265 and a second support structure 266 that are integral with or separate from the separator plate 255. Ribs 270a, 270b are similar to the ribs described with reference to FIG. 2c. It is clear that ribs 270a, 270b are in contact with electrochemically active layer 210 near the edge of the layer.

[0139] As shown in FIGS. 2e and 2f, the peaks or tips of the second support structure 266 and ribs 270 of battery unit 201a contact the electrochemically active layer 210 of adjacent battery unit 201b, separating battery unit 201a from adjacent battery unit 201b. Thereby, a second fluid volume portion 285 is formed. As described above, the elements of the second support structure 266 are dome-shaped, pyramid-shaped or cone-shaped (or similar), and thus do not create a restriction to the movement of the second fluid within the second fluid volume portion 285. However, since the ribs are elongated, they limit the outflow of the second fluid (e.g., oxidant) from the second fluid volume portion in a direction perpendicular to the long axis of the ribs.

[0140] It is further shown that battery units 201a, 201b have a flanged outer peripheral feature 275 around their outer periphery. The flanged outer peripheral feature 275 extends from the main planes of separator plate 255 and metal support plate 205 as seen in the central fluid volume portion region, forming a concave surface (forming a recess on the outer surface) on separator plate 255 and metal support plate 205. This concave surface forms the first fluid volume portion 280 within this fuel cell unit during assembly of the fuel cell unit, enabling the battery unit to be formed as a spacerless coupon, thereby reducing the number of parts.

[0141] The peripheric feature 275 with flange may be formed by pressure molding or molding, and may be formed simultaneously with the support structure 265 and the second support structure 266. The peripheric feature 275 with flange is shown on both the metal support plate 205 and the separator plate 255, but may be equally formed on either the metal support plate 205 or the separator plate 255. Since it is more difficult to coat the formed metal support plate with the battery chemical substance, it is more convenient if it does not include the peripheric feature with flange.

[0142] Figure 2d shows a weld line 239 around the outer periphery with flange that seals the first fluid volume of the coupon. (The weld is shown as a dashed line in the plane and as a triangle for stake welding in the cross section.) A weld line 237 is also provided around the second fluid intermediate port 235 to seal the first fluid volume 280 from the second fluid volume 285.

[0143] In Figure 2e, the first fluid end ports 240a, 240b include convex hard stop features 253 that extend towards the adjacent battery units. Such formed port features around these end ports require an insulating layer between the battery units, and an insulating and compressible sealing gasket may be provided (e.g., disposed within the annular hard stop 253), or a sealing paste may be applied to the hard stop and cured in place to form the insulating layer.

[0144] The peripheric feature 275 with flange functions to provide a margin for the spacer plate or gasket 260 in Figures 2b and 2c. A gasket or spacer (such as the gasket or spacer 261 in Figure 2b) may remain around the port. Alternatively, as shown in Figures 2d to 2f, formed port features 238 may also be formed around each of the ports to replace the spacer, and in some examples, the gasket may also be replaced by the formed port features.

[0145] Figures 3a and 3b show in detail and by way of example how formed port features can be formed around any or all of the ports shown in Figures 2a and 2d, how an intermediate port can have a structure in which it can be in fluid communication with a certain fluid volume but sealed from another fluid volume, and how a 3D structure can be ensured such that a sealing load / force is transmitted in the stack direction. In some cases, it will be apparent that formed port features such as dimples allow fluid communication between a fluid chimney and a fluid volume, and in some cases, formed port features prevent fluid communication between a fluid chimney and a fluid volume. A gasket disposed around the fluid chimney (and optionally next to the formed port feature) can additionally or alternatively prevent fluid communication between the chimney and the fluid volume.

[0146] Figure 2g shows a further spacerless coupon variant in which conveniently the metal support plate 205 is flat and the flanged peripheral feature 275 and the (larger) formed port feature 238 are provided only on the metal separator plate 255. In this variant, the end ports 240a, 240b are sealed by a conventional compressible insulating gasket 251 that defines an end port (first) fluid passage extending through the stack. Such a gasket 251 may be placed during stack assembly by known alignment assembly methods, and since the battery units are arranged in series, the gasket needs to be insulating between adjacent battery units. The second fluid intermediate port passage is defined and sealed from the first fluid volume by a pressure-formed flanged annular region around the second fluid intermediate port 235 provided in the metal separator plate 255, and this region is stake welded by an annular weld around the entire port.

[0147] Finally, FIG. 2h shows the middle section of two alternative framed spacers that can be used, for example, in the spaced-apart coupons of FIG. 2a, with pairs of battery chemistries 210 shown on either side of the line of the middle ports. In either case, (dashed) weld lines are shown around the outer perimeter and the central second fluid middle port. The left spacer can be a single continuous spacer frame, which avoids placing a central spacer, but means that the first fluid can only exit each port through the throat. Further, this version shows one first fluid middle port dedicated to / delivering to only one battery region. The right version shows delivery to both chemical regions of each second fluid middle port. However, in this version, a separate central spacer 261 needs to be fixed in place by welding that seals the second fluid passage, and additional fixing spacer components 261 can be provided if additional throats are needed. It will be appreciated that a battery unit having an internal spacer near the middle port should have a spacer structure that transmits the force to seal the passage in the stack direction and still have a throat that allows fluid to exit the port into the coupon internal fluid volume.

[0148] In each of the three respective battery unit variations of FIG. 2 (i.e., both with and without spacers), it is desirable to seal the first fluid volume as a fuel volume by peripheral welding through all of the respective plate components of the battery unit around the entire outer perimeter of the battery and also by welding around the second fluid middle port (or more generally any internally manifolded second fluid port passage).

[0149] As an example, FIGS. 3a and 3b show how port features can be formed having port features depicted in perspective and cross-sectional views. The ports are shown as being at the curved corners of the battery unit, but the molded port features described with reference to FIG. 3 may be equally disposed around any of the ports described herein.

[0150] Figure 3 shows a fluid port 322 surrounded by a molding port feature 324 and a gasket 334 provided to cover a recess formed by the molding port feature 324 during assembly. The molding port feature 324 is provided on the separator plate 255. The molding port feature 324 extends until it contacts the metal support plate 205, and its lowermost surface lies in a first plane that is the same plane as the flanged outer peripheral feature 275, while its uppermost surface and the remaining portion of the separator plate 255 lie in a second plane spaced apart from the metal support plate 205 so as to define a fluid volume portion 320. The fluid volume portion 320 is one of the first fluid volume portion 280 and the second fluid volume portion 285.

[0151] The molding port feature 324 has grooves in its innermost region, and these grooves are open to the fluid port 322. Then there are two alternating circles of circular recesses, followed by a final circle in which the grooves and circular recesses are alternately arranged, and these grooves have a length of approximately twice the diameter of the circular recesses. In this embodiment, the grooves are radially aligned with the inner of the two alternating circles of circular recesses and are arranged alternately with respect to the grooves in the innermost region. The circular recess of the final circle is instead radially aligned with the second of the two alternating circles of circular recesses. This arrangement forms a passage through which fluid can flow (from the fluid port into the interior of the fuel cell unit or in the reverse direction in the case of ventilation) between the recesses inside the fuel cell unit.

[0152] In addition to the recesses and / or grooves forming the molding port feature 324, a raised member 320 is provided. These raised members 320 are arranged in a circle outside the outer periphery of the gasket 334 and provide the following two functions.

[0153] First, by allowing the gasket to fit inside the ring of the raised member 320, it provides a guide for the position of the gasket 334 so that it fits in the correct position with respect to the fluid port 322, that is, at the center of the fluid port 322, during the assembly of the fuel cell stack.

[0154] Second, as shown in FIG. 3b, the raised member 320 has a height h that is preferably less than 75 to 99%, or more preferably 75 to 85% (e.g., 78 to 82%) of the thickness t of the gasket 334. The ratio of height h to thickness t can be adjusted according to the compression requirements of the specific gasket used. To provide the first function, such a large height h is not necessary, and thus, it can alternatively be a not-so-high height (e.g., h can be 5 to 75% of the thickness t of the gasket), but to provide the second function of providing a hard stop during stack assembly and lamination, a higher height is preferred. This hard stop function can be useful during the manufacture of the fuel cell stack because, since the gasket is compressible, it can cover and seal the recesses on the outer surface of the fuel cell unit during compression, and there is a possibility of over-compressing the stack during assembly. This over-compression can cause cracks or otherwise damage the electrochemically active layer on the metal support plate because the support structures 265, 266 also come into contact with these electrochemical layers during compression of the gasket. By having a hard stop, the degree of compression can be limited, whereby over-compression can be prevented by the hard stop, and unexpected cracking of the electrochemically active layer on the metal support plate can be prevented (thus, the allowable value of the engagement pressure within the fuel cell between the central protrusion and the electrochemically active layer is improved).

[0155] Alternatively, the raised member 320 may be a continuous annular raised member. As used herein, the shaped port feature refers to one or both of the raised member 320 and the shaped port feature 324.

[0156] However, it is important that these raised members 320 do not exceed the thickness t of the gasket 334, because otherwise the gasket cannot be compressed during the lamination process, and similarly, the electrical connection between the electrochemically active layer and the central protrusion may not be made, thus preventing the efficient operation of the stack and potentially causing hot spots to occur within the stack. Nevertheless, the actual height h of the raised member 320 may be appropriately changed or set during assembly to ensure proper sealing of the recess on the outer surface of the fuel cell unit by the gasket and proper electrical connection of the entire set of central protrusions 330, thereby achieving the necessary compression of the gasket and thus the correct connection between the electrochemically active layer and the central protrusion. An electrically insulating coating or paste layer may be used on one or both of the abutting surfaces (the hard stop surface formed by the raised member 320 and the metal substrate of the adjacent fuel cell unit) of the adjacent fuel cell units to prevent electrical contact between the adjacent fuel cell units through the abutting surfaces.

[0157] In a variation of this, instead of a raised member surrounding the outer periphery of the gasket 334, the gasket can have a form or hole inside for accommodating the raised member 320, and thus also provides a fixed position of the gasket with respect to the raised member 320 and potentially a fixed orientation of the gasket with respect to it (or, if the gasket can conform to more than one fixed orientation, multiple fixed orientations).

[0158] In a modification of this, the raised member 320 surrounding the outer periphery of the gasket is formed on the metal support plate 205 extending toward the separator plate 255 of the adjacent fuel cell unit. In a further modification, the raised members are formed on the metal support plate 205 and the separator plate 255, and these raised members may be spaced apart from each other. Further, the raised members of the metal support plate 205 and the separator plate 255 have an intermediate height, and their raised features abut against each other to form matching raised members having the same overall height as when the height of the raised member is provided by the raised member of the separator plate 255 or the metal support plate 205, or they may be spaced apart from each other on both the separator plate 255 and the metal support plate 205.

[0159] FIG. 4 shows the battery unit 200 of FIGS. 2A-2C having an exemplary fluid flow path extending between ports within the battery unit 200. The hatched arrow 405 represents the fluid flow path of the first fluid, and the white arrow 410 represents the fluid flow path of the second fluid. Typically, when operating in the SOFC mode, the first fluid may be fuel and the second fluid may be an oxidant (or air). Generally, the intermediate port(s) is / are fluid inlet port(s). As a result, the fluid input to the battery unit, the hot fluid, is input toward the center of the battery unit. This shortens the warm-up time of the stack and promotes a uniform heat distribution. Nevertheless, when the intermediate port is an outlet port (and thus the fluid enters the fluid volume from the respective opposite ends), a symmetric flow path toward the intermediate port promotes a uniform heat distribution.

[0160] FIG. 4a shows a plan view of the fluid flow paths between various channels, and FIG. 4b shows a cross-sectional view of the fluid flow path, the cross-section of which is along line A-A of FIG. 4a. In FIG. 4a, arrow 405 representing the first fluid flow path and arrow 410 representing the fluid flow path of the second fluid should be understood to represent the flow paths on the second side and the first side of the metal support plate 205, respectively (i.e., clearly, the flow depicted by arrow 405 occurs under the metal support plate 205 and thus would not be visible in the plan view (i.e., those arrows could alternatively be shown as dotted arrows)). This is clear in FIG. 4b, where the second fluid flow path 410 is within the second fluid volume portion 285 and is present on the first side of the metal support plate 205 (coated with the active chemical substance), i.e., on top of the cathode layer 213 of the electrochemically active layer 210. As also shown in FIG. 4b, the first fluid flow path 405 is within the first fluid volume portion 280 and is on the second side of the metal support plate (in fluid communication with the anode layer 211 via the porous region 214).

[0161] The first fluid flow path 405 is between the first fluid intermediate ports 230a, 230b and a pair of first fluid end ports 240a, 240b. The direction of the arrow represents the direction of the first fluid flow path. In this case, the first fluid intermediate ports 230a, 230b are inlet ports for fluid to enter the first fluid volume portion 280, and the first fluid end ports are outlet ports or discharge ports for fluid to exit the first fluid volume portion 280. The first fluid (e.g., fuel) is fully manifolded internally.

[0162] The second fluid flow path 410 is between the second fluid intermediate port 235 and the external manifold 245. The direction of the arrow represents the direction of the second fluid flow path. In this case, the second fluid intermediate port 235 is an inlet port for fluid to enter the second fluid volume portion 285, and the external manifold allows fluid to exit from the second fluid volume portion 285. The external manifold may simply be a gap or space between the battery and an external jacket or housing. The second fluid intermediate passage is formed by the second fluid intermediate port 235, and the passage is sealed from the first fluid volume portion by forming an annular port feature (see FIG. 3) or a gasket 415. If the latter is a conductive gasket or spacer, or an annular molded port feature, the intermediate passage may be sealed by welding or brazing through the conductive gasket or formed port feature around the intermediate port.

[0163] Thus, the first fluid flow path and the second fluid flow path extend from their respective intermediate ports and are symmetric with respect to the intermediate ports. The flow paths are schematically shown by arrows indicating the general direction of flow. In reality, since the flow is not restricted when the flow exits or spreads from the battery chemicals, it will be understood that the flow generally spreads radially or fan-shaped onto the battery chemicals from each port. In particular, there are no three-dimensional channels that force the flow into a specific meandering flow path. Rather, the flow is not restricted except near or at the outer periphery of the electrochemically active layer 210. Thus, for example, an arrow representing the flow path from the first fluid intermediate port 230a to the first fluid end port 240a is shown, but that arrow represents multiple flow paths between the ports, ensuring that the first fluid is supplied to each part of the electrochemically active layer 210 and the discharged fluid is removed from each part of the electrochemically active layer 210. However, each of the multiple flow paths between the ports represented by the arrow has major components between the edge of the electrochemically active layer 210 close to the intermediate port 230a and the opposite edge of the electrochemically active layer 210 close to the end port 240a (which is also parallel to the length of the battery unit). The same is true for all other fluid flow paths described herein.

[0164] Furthermore, referring to FIG. 3, it can be understood that the flow to and from each port is radial (at least in the vicinity of the port). That is, the shaping port feature does not direct the flow in a specific direction (the access to the port is non-directional or isotropic).

[0165] The raised port feature (such as that described with reference to FIG. 3, not shown in FIG. 4) and / or the interconnecting dimples 265 can avoid the collapse of the intermediate port. The raised port feature described with respect to FIG. 3 provides a way to seal the intermediate port passage and enable supply from the passage to the fluid volume.

[0166] The positions of the gasket 415 around the first fluid intermediate port 230 and the gasket 262 around the first fluid end port 240 are further shown in FIG. 4a. The gaskets 415 and 262 contact the first side of the metal support plate 205 (which is also the side that supports the electrochemically active layer 210). In a stack of battery units as shown in FIG. 4b, the gaskets 415 and 262 are disposed between the metal support plate 205 and the separator plate 255 of the next battery unit, separating the first fluid volume 280 and the second fluid volume 285.

[0167] The region 420 where the rib 270 contacts the electrochemically active layer 210 is also shown in FIG. 4a. The rib 270 is parallel to the length of the battery unit and contacts the electrochemically active layer 210 along the edge of the electrochemically active layer 210. Thus, the rib 270 functions to contain a second fluid (e.g., air) within the second fluid volume 285 as represented by the second fluid flow path 410 in FIG. 4a.

[0168] As shown in FIG. 4a, the rib extends beyond the edge of the electrochemically active layer 210, but in this extended region, the rib 270 contacts or is disposed on an insulating electrolyte layer that extends beyond the edge of the electrochemically active layer 210 shown in FIG. 4a.

[0169] The rib 270 (represented in the figure by the region 420 where the rib 270 contacts) extends towards the outer edge of the gasket 415 of the intermediate port 230 and may contact the outer diameter of the gasket 415. Thus, the gasket 415 (containing the first fluid) and the rib 270 cooperate (to form a continuous barrier) to direct the second fluid by restricting the second fluid from exiting the second fluid volume portion 285 in a direction perpendicular to the length of the battery. That is, the gasket 415 and the rib 270 contain the second fluid and direct the second fluid flow path 410 from the second fluid intermediate port 235 over the electrochemically active layer 210 to the external manifold 245. The gasket 262 around the first fluid end port 240 restricts the second fluid flow path 410 to also flow around the gasket 262.

[0170] Thus, the first fluid enters the first fluid volume portion 280 in the middle of the length of the battery unit 200 and exits near the end of the battery unit. Similarly, the second fluid enters the second fluid volume portion 285 in the middle of the length of the battery unit 200 and exits past the end of the battery unit. This can improve thermal management. Also, it enables a low aspect ratio arrangement of the first fluid volume portion and the second fluid volume portion, and the first fluid flow path 405 and the second fluid flow path 410 cross the short side (approximately half of the battery length) of the electrochemically active layer 210 rather than the long side (approximately the battery width) of the electrochemically active layer 210. The low aspect ratio means that the ratio between the width (the distance between the inlet port and the outlet port), labeled x1 in FIG. 2a, and the length, labeled y1 in FIG. 2a, of the active battery chemical substance layer is 1.2 or less (i.e., x1 / y1 ≦ 1.2). In one example, the aspect ratio is less than 1, in another example, the aspect ratio is less than 0.8, and in another example, the aspect ratio is between 0.3 and 0.8. Having a low aspect ratio arrangement reduces the pressure drop between the inlet and outlet of the volume portion and reduces the thermal gradient between them.

[0171] The rib 270 is close to the first fluid intermediate port and is a depression when viewed from the first fluid volume portion 280. Thus, it forms a delivery channel for delivering the first fluid (e.g., fuel) to the first fluid volume portion 280, whereby the first fluid can flow out of the rib along its length. This promotes a uniform flow across the region, despite there being a single first fluid central end port 240, by promoting the flow of the fluid to the outermost corners of the active chemical region (and the stack).

[0172] In FIGS. 4a and 4b, the directions of the first fluid flow path and the second fluid flow path from the center of the battery unit 200 towards the end of the battery unit 200 are shown (by the direction of the arrows). With respect to FIGS. 4c, 4d, and 4e, various alternatives will be described. Each of FIGS. 4c, 4d, and 4e has the same port arrangement within the battery unit 200 as described with respect to FIGS. 2a - 2d, 4a, and 4b.

[0173] FIG. 4c shows a counter - flow arrangement where the direction of the first fluid flow path is generally opposite to the direction of the second fluid flow path. The direction of the second fluid flow path 410 remains from the center of the battery to the end of the battery, while the direction of the first fluid flow path 406 is arranged to go from the end of the battery unit to the center of the battery unit. That is, the first fluid flows from the first fluid end port 240 to the first fluid intermediate port 230.

[0174] FIG. 4d shows a second counter - flow arrangement. In this case, the direction of the first fluid flow path 405 is from the center of the battery towards the end of the battery, while the direction of the second fluid flow path 411 is arranged to go from the end of the battery unit to the center of the battery unit. That is, the second fluid flows from the external manifold 245 to the second fluid intermediate port 235.

[0175] Figure 4e shows a co - flow arrangement where the first fluid flow path and the second fluid flow path are generally in the same direction (similar to the co - flow arrangements in FIGS. 4a and 4b in this sense). In this case, the direction of the first fluid flow path 406 is arranged to be from the end of the battery unit towards the center of the battery unit. That is, the first fluid flows from the first fluid end port 240 to the first fluid intermediate port 230. The direction of the second fluid flow path 411 is arranged to be from the end of the battery unit towards the center of the battery unit. That is, the second fluid flows from the external manifold 245 to the second fluid intermediate port 235.

[0176] Figure 4f shows the battery unit 200 of FIG. 4a with an alternative rib arrangement. Again, the discontinuous ribs 270 of the separator plate (represented in the figure by the region 420 where the ribs 270 contact) extend towards the outer edge of the gasket 415 of the intermediate port 230, but the rib ends curve towards the port (in a hockey - stick shape) to minimize the gap between the rib and the gasket. The second fluid (air / oxidant) flow path is not shown for clarity but is the same as that shown in FIG. 4a. Some air escapes between the rib ends and the gasket, but the curvature minimizes this distance (and thus the escape). (An example of a battery with a continuous battery chemical region and a single continuous rib is shown in FIG. 8.)

[0177] The ribs improve fuel distribution to the corners of the battery by providing fuel fluid delivery channels in the first fluid (fuel) volume from which additional fuel flow paths 406 can branch. In one test, the ribs increased the fuel under the ribs by more than 10%.

[0178] FIG. 5 shows a variant in which the electrochemically active layer 510 is wound around the first fluid end port 240, i.e., the electrochemically active layer extends at least partially around the port, preferably having an edge of the corresponding contour of the electrochemically active layer. Extending at least partially around the port means that the corresponding contour may be greater than 90°, or greater than 180°, or 360° (e.g., FIG. 8a). In other respects, the electrochemically active layer 510 is similar to the electrochemically active layer 210 described above. The edge of the electrochemically active layer 510 proximate to the first fluid end port 240 is deposited in a semi-circular or arcuate shape along the circular shape of the port 240. The annular gap between the end port 240 and the electrochemically active layer 510 allows for the placement of a gasket (e.g., the gasket 262 described with respect to FIG. 4a) around the end port 240, and this annular gap means that the gasket does not contact the cathode of the electrochemically active layer 510. The gasket may contact and rest on the extended electrolyte layer. Alternatively or additionally, the annular gap provides a space for the shaped port feature surrounding the port. The wound electrochemically active layer 510 can further be positioned towards the end of the metal substrate 205 at the edge of the electrochemically active layer 510 (e.g., at the same height as the middle of the end port 240), thus enabling the electrochemically active layer 510 to cover a larger proportion of the metal substrate 205 (compared to those without the wound electrochemically active layer).

[0179] The electrochemically active layer 510 may alternatively or additionally be wound around any of the other ports within the battery unit, e.g., around the first fluid intermediate port and / or the second fluid intermediate port, in a similar manner as the winding around the first fluid end port 240.

[0180] FIG. 6 shows a variant where the first and second fluid ports are non-circular but otherwise similar to those described above. Each of the ports is shown as rectangular, but they may equally well be elliptical or square. Again, the electrochemically active layer 510 is shown wrapped around the perimeter of the first fluid end port 640. Wrapping is more desirable for circular or elliptical ports than for rectangular or square ports which occupy less space on the metal support plate 205. Further, by using intermediate ports that are elongated along a centerline (such that the intermediate ports are longer in the minor axis direction of the battery unit than they are wide in the major axis direction of the battery unit), the intermediate ports 630, 635 occupy substantially all of the area of the metal support plate 205 between the electrochemically active layers 510, enabling the electrochemically active layer 510 to cover a greater proportion of the metal substrate 205.

[0181] With regard to the previous discussion of desirable dimensions, minimum length x1 and minimum width y1 of the electrochemically active layer are added here for purposes of illustration (and could similarly be added to FIG. 5). Width y1 is the same as that in FIG. 2a. Length x1 is the minimum value across the electrochemically active layer between the edge of the electrochemically active layer proximate to the intermediate port and the end of the electrochemically active layer proximate to the end port. Length x1 is parallel to the edge of the electrochemically active layer and the edge of the battery unit (e.g., its length).

[0182] Wrapping of the active region is highly desirable in combination with providing a shaped delivery channel / rib for delivering fuel to the outermost corner regions of the battery chemistry so that fuel can reach the outermost corners of the battery chemistry since fuel starvation can occur in the outermost corner chemical regions. In this way, a greater proportion of the metal support plate may be covered by the electrochemically active layer and a high energy density can be achieved.

[0183] FIG. 7 shows a modified battery unit in which the second fluid is also manifolded internally and otherwise the battery unit is similar to the unit described previously. The battery unit includes a pair of offset second fluid end ports 745a and 745b disposed one at each end of the first (long) axis of the battery unit 200. The second fluid end ports are for the delivery or removal of the second fluid from the battery unit. The second fluid end ports 745a, 745b are closer to the ends of the first (long) axis of the battery unit 200 than the electrochemically active layer 210. The second fluid end ports replace the external manifold 245 of the previous figures and form the end fluid passages within the stack for the second fluid. Since the second fluid is fully manifolded internally (using the intermediate ports 235 and the end ports 745), the ends of the battery unit may be positioned very close to the inner ends of the housing in which the stack is disposed.

[0184] Although one second fluid end port is shown at each end of the battery unit, more second fluid end ports may be provided. For example, there may be two second fluid end ports at each end of the battery unit with a first fluid end port disposed therebetween. This maintains symmetry for a uniform flow.

[0185] FIG. 7 also shows the fluid flow path and the fluid flow direction (represented by the arrow) in a plan view. The first fluid flow path 405 and the flow direction are as described with reference to FIGS. 4a and 4b. The second fluid flow path 785 is between the second fluid intermediate port 235 and the second fluid end ports 745a, 745b. The directions of both the first fluid (of the first fluid flow path 405) and the second fluid (of the second fluid flow path 785) are shown to be from the center of the battery unit, i.e., the intermediate port, towards the ends of the battery unit. That is, the directions of the first fluid flow path and the second fluid flow path are generally in a co-flow arrangement, similar to the arrangement described with respect to FIGS. 4a and 4b. Similarly, by reversing either the direction of the first fluid flow path or the second fluid flow path, a counter-flow arrangement similar to the arrangement described with respect to FIGS. 4c and 4d can be provided, or by reversing both the directions of the first fluid flow path and the second fluid flow path, a co-flow arrangement similar to the arrangement described with respect to FIG. 4e can be provided. Further, it should be understood that any of the other variations described earlier or later can have a second fluid volume that is fully internally manifolded as in FIG. 7.

[0186] FIGS. 8a and 8b show a further modified battery unit in which there is a single electrochemically active layer 810, in contrast to the two separate active layers 210 described earlier. In other respects, this variation is similar to the battery unit described earlier. The single electrochemically active layer 810 surrounds the first fluid intermediate port 230 and the second fluid intermediate port 235. That is, a portion of the electrochemically active region 810 is disposed between the intermediate ports 230, 235 and the long sides of the battery unit, which means that the electrochemically active layer is a single continuous region. Thus, the single electrochemically active layer 810 can cover a larger proportion of the metal support plate 205 than in the case of the two electrochemically active layers 210.

[0187] FIG. 8b shows the battery unit of FIG. 8a having an exemplary fluid flow path extending between ports within the battery unit. The first fluid flow path 405 and the second fluid flow path 410 are similar to the fluid flow paths described with reference to FIGS. 4a and 4b, and one or both of them may be reversed as described in FIGS. 4c-4e.

[0188] Also shown in FIG. 8b is a region 820 that contacts continuous ribs 270 provided on the separator plates of adjacent battery units within the stack. The region 820 and the associated ribs are similar to the two regions 420 and the two ribs along each long side of the battery unit of FIG. 4a, except that in this variation, the ribs and the region 820 where the ribs contact are continuous along the length of the battery unit so as to eliminate the bypass of air from between the gasket and the rib ends. As before, the ribs are ribs along the length of the separator plates of adjacent battery units and contact the first battery unit when the first battery unit and the adjacent battery unit are arranged in the stack. That is, the region 820 where the ribs contact is along the electrochemically active layers 810 disposed on both sides of the intermediate port and along the portion of the electrochemically active layer 810 between the intermediate port and the long side of the battery unit. Thus, the ribs contacting the region 810 function to contain the second fluid within the second fluid volume. The ribs are close to the first fluid intermediate port and are depressions when viewed from the first fluid volume, thus forming a delivery channel for delivering the first fluid to the first fluid volume, whereby the first fluid can flow out of the ribs along its length.

[0189] FIGS. 9a-9c show a variation where there is a single first fluid intermediate port and no second fluid intermediate port, and otherwise the variation is similar to that described previously. The first fluid intermediate port 930 is disposed at the center within the battery unit. The first fluid end ports are disposed towards the corners of the battery unit. Thus, the first fluid ports form an "X" shaped cross.

[0190] The second fluid is manifolded externally, as represented by an external manifold 245a disposed at the first end of the battery unit and an external manifold 245b disposed at the second end of the battery unit. The external manifolds 245a and 245b are similar to the aforementioned external manifold 245 and may each extend in the stacking direction.

[0191] The electrochemically active layer 810 surrounds a first fluid intermediate port 930, similar to the electrochemically active layer 810 described with reference to FIG. 8. Alternatively, the electrochemically active layer may comprise a separate electrochemically active layer, similar to the electrochemically active layer 210 described above. Alternatively, further, similar to the two fluid intermediate ports previously described with respect to FIGS. 2 and 4, there may be a plurality of first fluid intermediate ports disposed along the center of the length of the battery unit.

[0192] FIG. 9b shows the first fluid flow path 905 and the second fluid flow path 910 of the modified battery unit of FIG. 9a. The first fluid flow path 905 takes the form of a cross or an "X" shape.

[0193] The second fluid flow path is between the external manifold 245a at the first end of the battery unit and the external manifold 245b at the second end of the battery unit. The second fluid flow path 910 is housed within the second fluid volume by ribs (projecting from the separator plates of adjacent battery units) that contact the electrochemically active layer 810 in region 820. The second fluid flow path 910 passes through the first fluid intermediate port 930 and around a gasket (not shown) surrounding the first fluid intermediate port 930 to separate the first fluid volume and the second fluid volume.

[0194] The direction of the first fluid flow path is shown from the intermediate port 930 to the end port 940. The direction of the second fluid flow path is shown from the external manifold 245a at the first end of the battery unit to the external manifold 245b at the second end of the battery unit. Thus, half of the battery unit has co - flow and the other half of the battery unit has counter - flow. Similarly, the direction of the first fluid flow path may be reversed so that the first fluid flows from the first fluid end port 940 towards the first fluid intermediate port 930. In this case, here too, half of the battery unit has co - flow and the other half of the battery unit has counter - flow. The co - flow of half of the battery unit and the counter - flow of the other half of the battery unit result in an asymmetric heat distribution, which is not advantageous.

[0195] Figure 9c shows a modification of the arrangement of FIGS. 9a and 9b, in which the second fluid is manifolded internally using the second fluid end ports 745a and 745b. The second fluid end port 745a is arranged towards the first end of the battery unit, and the second fluid end port 745b is arranged towards the second end of the battery unit. The second fluid end ports 745 at each end of the battery unit are arranged intermediate along the end of the battery unit, between the first fluid end ports 940 (one first fluid end port 940 is arranged towards each corner of the battery unit). The first fluid flow path 905 and the first fluid flow direction are the same as those described with respect to FIG. 9b. Similarly, the second fluid flow path 910 and the second fluid flow direction are the same as those described with respect to FIG. 9b.

[0196] Figures 10a and 10b show a further modified battery unit in which the first fluid and the second fluid are in a cross-flow arrangement. There is a single first-fluid intermediate port 930 and no second-fluid intermediate port. Further, there is no first-fluid end port. Instead, as represented by an external manifold 1040a disposed at the first end of the battery unit and an external manifold 1040b disposed at the second end of the battery unit, the first fluid is manifolded externally. The external manifolds 1040 are outside the area covered by the metal support plate 205 and form the end fluid passages of the first fluid.

[0197] Fluid side ports 1041, 1046 that are in fluid communication with the second-fluid volume are provided for the delivery and discharge of the second fluid. The side ports are disposed along the long sides of the metal support plate 205 beyond the electrochemically active layer 810. As shown in FIG. 10a, two fluid side ports 1041 are disposed along the first edge of the metal support plate 205, and further two side ports 1046 are disposed along the second edge of the metal support plate 205, and the first edge and the second edge face each other with the electrochemically active layer 810 therebetween.

[0198] FIG. 10b shows the first-fluid flow path 1005 and the second-fluid flow path 1010 of the modified battery unit of FIG. 10a.

[0199] The first-fluid flow path 1005 is between the first-fluid intermediate port 930 and the external manifolds 1040a, 1040b. The second-fluid flow path 1010 is between the fluid side port 1041 at the first edge of the battery unit and the fluid side port 1046 at the second edge of the battery unit. The second-fluid flow path 1010 passes through the first-fluid intermediate port 930 and around a gasket (not shown) surrounding the first-fluid intermediate port 930 to separate the first-fluid volume and the second-fluid volume.

[0200] The direction of the first fluid flow path 1005 is shown from the intermediate port 930 to the external manifolds 1040a, 1040b. The direction of the second fluid flow path 1010 is shown from the fluid side port 1041 at the first edge of the battery unit to the fluid side port 1046 at the second edge of the battery unit. Thus, the flow is in an alternating current configuration across the battery unit. Similarly, the direction of the first fluid flow path may be reversed so that the first fluid flows from the external manifolds 1040a, 1040b towards the first fluid intermediate port 930, and in this case as well, the flow is an alternating current across the battery unit.

[0201] If the repeating unit of the battery is, for example, a sealed unit having a sealed fluid volume that provides both a battery end port and a battery intermediate port with an internal manifold, other fluids may be manifolded externally for both inlet and / or outlet purposes.

[0202] Figures 11a - 11c show a further modified battery unit having four first fluid end ports and two second fluid intermediate ports. The two second fluid intermediate ports 1135a, 1135b are disposed in the middle of the length of the battery unit, and an electrochemically active layer is coated or deposited between the second fluid intermediate ports 1135a, 1135b and the ends of the battery unit. The first fluid intermediate port 1130 is in the middle along the length of the battery unit and is disposed between the two second fluid intermediate ports 1135a, 1135b.

[0203] Towards each corner of the battery unit, the first fluid end port 940 is disposed. The first fluid end port 940 is distal to the middle of the width of the battery unit. The first fluid end port 940 and the first fluid intermediate port 1135 are in fluid communication with each other. Thus, the first fluid end port 940 and the first fluid intermediate port 1130 form a cross or "X" shape with the first fluid intermediate port 1130 at the center of the cross. The external manifold 245 is in fluid communication with the second fluid intermediate ports 1135a, 1135b.

[0204] FIG. 11b shows the first fluid flow path 1105 and the second fluid flow path 1110 of the modified battery unit of FIG. 11a. The first fluid flow path 1105 is between the first fluid intermediate port 1130 and the first fluid end port 940. The second fluid flow path is between the second fluid intermediate ports 1135a, 1135b and the external manifold 245. The direction of the first fluid flow path 1105 is shown from the intermediate port 1130 to the first fluid end port 940. The direction of the second fluid flow path 1110 is shown from the fluid intermediate port to the external manifold 245 at the end of the battery unit. Therefore, the flow is symmetric with respect to the two axes of the battery unit. The flow is in a co-flow configuration across the battery unit. The direction of the first fluid flow path may be reversed so that the first fluid flows from the first fluid end port 940 toward the first fluid intermediate port 1130. In this case, the flow is a counter-flow across the battery unit. Similarly, the flow direction of the second fluid flow path 1110 may be reversed so that the second fluid flows from the external manifold 245 toward the second fluid intermediate port 1135. In this case, the flow is a counter-flow across the battery unit. When both the flow direction of the first fluid and the flow direction of the second fluid are reversed (as indicated by the arrows in FIG. 11b), both fluids flow toward the center of the battery unit in a co-flow configuration.

[0205] FIG. 11c shows a modification of the arrangement of FIGS. 11a and 11b in which the second fluid is internally manifolded using the second fluid end ports 745a and 745b. The second fluid end port 745a is arranged toward the first end of the battery unit, and the second fluid end port 745b is arranged toward the second end of the battery unit. The second fluid end ports 745 at each end of the battery unit are arranged in the middle along the end of the battery unit, between the first fluid end ports 940 (one first fluid end port 940 is arranged toward each corner of the battery unit). The first fluid flow path 1105 and the first fluid flow direction are the same as those described with respect to FIG. 11b. Similarly, the second fluid flow path 1110 and the second fluid flow direction are the same as those described with respect to FIG. 11b.

[0206] Figures 12a to 12c show a further modified battery unit having two first fluid intermediate ports and two second fluid intermediate ports. The fluid intermediate ports are arranged in the middle of the length of the battery unit and towards the side of the battery unit (i.e., spaced from the midline in the width direction of the battery unit). Arranged towards the first side of the battery unit are the first fluid intermediate port 1230a and the second fluid intermediate port 1235a, and their centers are aligned with an axis parallel to the length direction of the battery unit. The first fluid intermediate port 1230a is farther from the external manifold 245a than the second fluid intermediate port 1235a (arranged at the left end of the battery unit). Arranged towards the second side of the battery unit are the first fluid intermediate port 1230b and the second fluid intermediate port 1235b, and their centers are aligned with an axis parallel to the length direction of the battery unit. The axis along which the intermediate ports 1230b and 1235b are aligned is symmetrically arranged with respect to the midline in the width direction of the battery with respect to the axis on which the intermediate ports 1230a and 1235a are arranged. The second fluid intermediate port 1235b is farther from the external manifold 245a than the first fluid intermediate port 1230b (arranged at the left end of the battery unit). The electrochemically active layer is coated or deposited between the intermediate ports 1230a, 1230b and 1235a, 1235b and the ends of the battery unit. As described above, the first fluid end port 240 is arranged towards the end of the battery unit, and the external manifold 245 is arranged across the battery unit. Therefore, the first fluid ports are arranged in a rhombus shape.

[0207] Figure 12b shows the first fluid flow path 1205 and the second fluid flow path 1210 of the modified battery unit of Figure 12a.

[0208] The first fluid flow path 1205 is between the first fluid intermediate ports 1230a, 1230b and the first fluid end port 240. The second fluid flow path 1210 is between the second fluid intermediate ports 1235a, 1235b and the external manifold 245.

[0209] The direction of the first fluid flow path 1205 is shown from the first fluid intermediate ports 1230a, 1230b to the first fluid end port 240. Since the flow from each port is isotropic, the fluid from the first fluid intermediate port 1230a flows around the second fluid intermediate port 1235a (and the accompanying gasket or molded port feature) and reaches the first fluid end port 240a (a part of the electrochemically active layer and the second fluid intermediate port 1235a is disposed between the first fluid intermediate port 1230a and the first fluid end port 240a). Similarly, the fluid from the first fluid intermediate port 1230b flows around the second fluid intermediate port 1235b and reaches the first fluid end port 240b.

[0210] The direction of the second fluid flow path 1210 is shown from the second fluid intermediate ports 1235a, 1235b to the external manifold 245 at the end of the battery unit. The fluid from the second fluid intermediate port 1235a flows around the first fluid intermediate port 1230a (and the accompanying gasket or molded port feature) and reaches the external manifold 245b (a part of the electrochemically active layer and the first fluid intermediate port 1235a is disposed between the second fluid intermediate port 1235a and the external manifold 245b). Similarly, the fluid from the second fluid intermediate port 1235b flows around the first fluid intermediate port 1230b and reaches the external manifold 245b.

[0211] Thus, the flow is generally symmetric with respect to the two axes of the battery unit. The flow is a co-flow arrangement across the battery unit. The direction of the first fluid flow path may be reversed such that the first fluid flows from the first fluid end port 240 towards the first fluid intermediate port 1230, in which case the flow is a counter-flow across the battery unit. Similarly, the flow direction of the second fluid flow path 1210 may be reversed such that the second fluid flows from the external manifold 245 towards the second fluid intermediate port 1235, in which case the flow is a counter-flow across the battery unit. If both the flow direction of the first fluid and the flow direction of the second fluid are reversed (as indicated by the arrows in FIG. 12b), both fluids flow towards the center of the battery unit in a co-flow arrangement.

[0212] FIG. 12c shows a modification of the arrangement of FIGS. 12a and 12b, in which the second fluid is internally manifolded using the second fluid end ports 745a and 745b. The second fluid end port 745a is arranged towards the first end of the battery unit, and the second fluid end port 745b is arranged towards the second end of the battery unit. The second fluid end ports 745 at each end of the battery unit are arranged approximately in the middle along the end of the battery unit, but may be arranged on one side of the middle such that the first fluid end port 240 and the second fluid end port 745 are offset in opposite directions from the midpoint of the battery unit. The first fluid flow path 1205 and the first fluid flow direction are the same as those described with respect to FIG. 12b. Similarly, the second fluid flow path 1210 and the second fluid flow direction are the same as those described with respect to FIG. 12b.

[0213] FIGS. 13a - 13c show a further modified battery unit having two first fluid intermediate ports 230 and one second fluid intermediate port 235 similar to those described with reference to FIG. 2. Also shown are the first fluid end ports 940 respectively arranged towards each corner of the battery unit, similar to those described with reference to FIG. 9.

[0214] FIG. 13b shows the first fluid flow path 1305 and the second fluid flow path 1310 of the modified battery unit of FIG. 13a.

[0215] The first fluid flow path 1305 is between the first fluid intermediate ports 230a, 230b and the first fluid end port 940. The second fluid flow path 1310 is between the second fluid intermediate port 235a and the external manifold 245.

[0216] The direction of the first fluid flow path 1305 is shown from the first fluid intermediate ports 230a, 230b to the first fluid end port 240. The direction of the second fluid flow path 1310 is shown from the second fluid intermediate port 235 to the external manifold 245 at the end of the battery unit.

[0217] Thus, the flow is symmetric with respect to the two axes of the battery unit. The flow is in a co-flow configuration across the battery unit. The direction of the first fluid flow path 1305 may be reversed so that the first fluid flows from the first fluid end port 940 towards the first fluid intermediate port 230. In this case, the flow is a counter-flow across the battery unit. Similarly, the flow direction of the second fluid flow path 1310 may be reversed so that the second fluid flows from the external manifold 245 towards the second fluid intermediate port 235. In this case, the flow is a counter-flow across the battery unit. If both the flow direction of the first fluid and the flow direction of the second fluid are reversed (as indicated by the arrows in FIG. 13b), both fluids flow towards the center of the battery unit in a co-flow configuration.

[0218] FIG. 13c shows a modification of the arrangement of FIGS. 13a and 13b in which the second fluid is manifolded internally using the second fluid end ports 745a and 745b. The second fluid end ports 745a, 745b are the same as those described previously with reference to FIG. 7. The first fluid flow path 1305 and the first fluid flow direction are the same as those described with respect to FIG. 13b. Similarly, the second fluid flow path 1310 and the second fluid flow direction are the same as those described with respect to FIG. 13b.

[0219] Figures 14a - 14c show a further modified battery unit in which a partition, a partition, or a baffle may be provided to divide the first fluid volume or the second fluid volume by causing some interference to the flow such that each of the intermediate ports can mainly direct the fluid to a specific battery chemical region. The partition can also fluidly separate the fluid volume into two volumes, but this requires an outer seal such as welding.

[0220] As previously described with reference to FIG. 2, there is a single second fluid intermediate port 235 disposed in the middle of the length and width of the battery unit. The second fluid intermediate port is in fluid communication with an external manifold 245. The two first fluid intermediate ports 230a, 230b are disposed in the middle of the length of the battery unit, one on each side of the second fluid intermediate port 235, and the first fluid end ports are provided towards each corner of the battery unit.

[0221] The partition 1490 is provided on or in contact with the second side of the metal support plate 205 and separates the fluid volume on that side of the metal support plate into two volumes. The partition 1490 is shown as being present in the first fluid volume of the second side of the metal support plate 205. The partition partitions the volume such that the first fluid intermediate port 230a is in fluid communication with the first fluid end ports 940c, 940d towards the second end of the battery unit and the electrochemically active layer 210b, and the partition partitions the volume such that the first fluid intermediate port 230b is in fluid communication with the first fluid end ports 940a, 940b towards the first end of the battery unit and the electrochemically active layer 210a.

[0222] The partition 1490 may be a feature formed or pressure - formed on either the metal support plate 205 or the separator 255, similar to the formed port feature, and may be formed in the same manufacturing process as the forming or pressure - forming of the formed port feature.

[0223] FIG. 14b shows the first fluid flow path 1405 and the second fluid flow path 1410 of the modified battery unit of FIG. 14a. The second fluid flow path 1410 is between the second fluid intermediate port 235a and the external manifold 245. The first fluid flow path 1405 is between the first fluid intermediate ports 230a, 230b and the first fluid end port 940. The first fluid flow path 1405 includes a first sub-flow path 1405a and a second sub-flow path 1405b separated by a partition 1490. The first sub-flow path 1405a is between the first fluid intermediate port 230b and the first fluid end ports 940a, 940b and is in fluid communication with the electrochemically active layer 210a. The second sub-flow path 1405b is between the first fluid intermediate port 230a and the first fluid end ports 940c, 940d and is in fluid communication with the electrochemically active layer 210b.

[0224] The direction of the first fluid flow path 1405 is shown from the first fluid intermediate ports 230a and 230b to the first fluid end ports 940c, 940d and 940a, 940b, respectively. The direction of the second fluid flow path 1410 is shown from the second fluid intermediate port 235 to the external manifold 245 at the end of the battery unit.

[0225] The flow is a co-flow configuration across the battery unit. The direction of the first fluid flow path 1405 may be reversed such that the first fluid flows from the first fluid end port 940 towards the first fluid intermediate port 230. In this case, the flow is a counter-flow across the battery unit. Similarly, the flow direction of the second fluid flow path 1410 may be reversed such that the second fluid flows from the external manifold 245 towards the second fluid intermediate port 235. In this case, the flow is a counter-flow across the battery unit. If both the flow direction of the first fluid and the flow direction of the second fluid are reversed (as shown by the arrows in FIG. 14b), both fluids flow towards the center of the battery unit in a co-flow configuration.

[0226] FIG. 14c shows a modification of the arrangement of FIGS. 14a and 14b in which a second fluid is internally manifolded using second fluid end ports 745a and 745b. The second fluid end ports 745a, 745b are the same as those described above with reference to FIG. 7. The first fluid flow path 1405 and the first fluid flow direction are the same as those described with respect to FIG. 14b. Similarly, the second fluid flow path 1410 and the second fluid flow direction are the same as those described with respect to FIG. 14b.

[0227] The battery of FIG. 14 may be formed from a single continuous metal substrate plate that supports two regions of battery chemistry, and this plate can be incorporated into a battery unit with or without spacers.

[0228] However, for example, for manufacturing reasons, if it is beneficial to have a plurality of smaller coated substrates, a single battery unit can be formed using a plurality of metal substrates, each having a battery chemistry region. In the case of two coated battery substrates, these can be joined, for example, by welding their abutting edges to form one metal substrate having a plurality of battery regions, which can then be incorporated into a coupon as described above.

[0229] Alternatively, it is not necessary to directly connect the plurality of coated battery substrates, but rather, for example, by resistance welding or brazing, to either a spacer and interconnect or an interconnect having 3D features that provide a fluid volume, to form, for example, a battery unit having a dedicated sealed fluid volume for each separate battery chemistry region.

[0230] These and other features of the invention have been described purely by way of example. Within the scope of the claims, modifications in detail may be made to the invention, particularly with respect to the shape of the fuel cell unit, the electrochemically active layers, and the arrangement of the ports for the first and second fluids.

Claims

Claim 1 A stack of rectangular planar electrochemical cell units, each of said cell units comprising at least one first fluid intermediate port disposed within or intermediate the lengths between one or more active cell chemical substance regions and in fluid communication with a first fluid volume of said cell unit, the first fluid intermediate ports of respective said cell units being aligned to form at least one first fluid intermediate passage extending in the stack direction, said stack being configured such that in each of said first fluid volumes, a first fluid flow path extends across said one or more active cell chemical substance regions between said at least one first fluid intermediate port and each corresponding opposing cell end, a stack of rectangular planar electrochemical cell units, wherein the dimension of said active cell chemical substance region between said intermediate port and one of said opposing ends of said cell unit parallel to said fluid flow path is less than or equal to the dimension of said active cell chemical substance region perpendicular to said fluid flow path. Claim 2 A stack of rectangular planar electrochemical cell units according to claim 1, wherein each of said cell units has at least two separate active cell chemical substance regions, each region being disposed between said intermediate port and each corresponding opposing cell end. Claim 3 A stack of rectangular planar electrochemical cell units according to claim 1 or 2, wherein each of said cell units has only one first fluid intermediate port in fluid communication with said first fluid volume. Claim 4 A stack of rectangular planar electrochemical cell units according to any one of claims 1 to 3, wherein each of said cell units comprises at least a first fluid end port and a second first fluid end port respectively disposed at or near each opposing cell end, said first fluid end ports of respective ones being aligned to define corresponding first interiors and second interiors, a first fluid end passage extending in said stack direction, whereby said intermediate and end first fluid passages respectively form an inlet passage and an outlet passage, or vice versa, in said stack for supplying a first fluid to said first fluid volume of each of said cell units. Claim 5 Each of the battery units further includes at least one second fluid intermediate port, the at least one second fluid intermediate port is disposed within or at an intermediate length between one or more active battery chemical substance regions, and is in fluid communication with a second fluid volume portion of the battery unit. The second fluid intermediate ports of each of the battery units are aligned to form at least one second fluid intermediate passage extending in the stack direction. The stack is configured such that, in each of the second fluid volume portions, each second fluid flow path extends across the one or more active battery chemical substance regions between the at least one second fluid intermediate port and each corresponding opposing battery end. The stack of rectangular planar electrochemical battery units according to any one of claims 1 to 4.

6. Each of the battery units includes two first fluid intermediate ports each in fluid communication with the first fluid volume portion and one second fluid intermediate port in fluid communication with the second fluid volume portion. Optionally, the second fluid intermediate port is disposed between the two first fluid intermediate ports. The stack of rectangular planar electrochemical battery units according to claim 5.

7. A first fluid end passage extending in the stack direction at or near each opposing stack end and in fluid communication with the first fluid volume portion is provided. The first fluid end passage is a passage manifolded internally and defined by a first fluid end port and a second first fluid end port aligned within each of the battery units. A second fluid end passage extending in the stack direction at or near each opposing stack end and in fluid communication with the second fluid volume portion is provided. The second fluid end passage is a passage manifolded externally across each battery unit. The stack of rectangular planar electrochemical battery units according to claim 5.

8. The first fluid volume portion is a fuel volume portion, and the second fluid volume portion is an oxidant volume portion. The stack of rectangular planar electrochemical battery units according to any one of claims 5 to 7.

9. The first fluid intermediate port is an inlet port. The stack of rectangular planar electrochemical battery units according to any one of claims 1 to 8.

10. The stack of rectangular planar electrochemical battery units according to any one of claims 1 to 9, wherein the one or more active battery chemical substance regions are wound around at least one of any intermediate ports or end ports provided in the battery unit.

11. The stack of rectangular planar electrochemical battery units according to any one of claims 1 to 10, wherein one of the first fluid volume portion or the second fluid volume portion is defined by a planar component having an elongated shaped feature, and the elongated shaped feature at least partially extends around the outer periphery of the active battery chemical substance region so as to define a fluid flow path within the region.

12. The stack of rectangular planar electrochemical battery units according to claim 11, wherein the elongated shaped feature comprises a feature forming at least one of a protruding rib on one side surface of the component and a channel on the other side surface of the component in the planar component, and optionally, the elongated shaped feature is a pressure-formed or shaped feature.

13. The battery unit is a separator plate, a metal support plate holding an active battery chemical substance region (which may be plural) provided on a porous region on a first side surface and includes the separator plate and the metal support plate overlap each other to form the battery unit, at least one of the separator plate and the metal support plate has a flanged outer peripheral feature formed by pressure-forming the plate into a concave shape, the separator plate and the metal support plate are directly adjacent to each other at the flanged outer peripheral feature and form the first fluid volume portion between the separator plate and the metal support plate, optionally by welding, at least one fluid port is provided in each of the separator plate and the metal support plate, the fluid ports are aligned to form the first fluid passage within the flanged outer peripheral feature, and each port is either the first fluid intermediate port and / or the first fluid end port and communicates with the first fluid volume portion. At least one of the separator plate and the metal support plate has a formed port feature formed around the at least one fluid port by pressure forming, the formed port feature extends towards the other plate, and elements of the formed port feature are spaced apart from each other to define a fluid passage from the port between the elements, enabling fluid to pass from the at least one first fluid port to the first fluid volume. The stack of rectangular planar electrochemical cell units according to any one of claims 1 to 12.

14. Furthermore, at least one fluid port is provided in each of the separator plate and the metal support plate, the fluid ports are aligned to form a second fluid passage within the flanged outer peripheral feature, each port is either a second fluid intermediate port and / or a second fluid end port, and communicates with a second fluid volume at a second side surface of the metal support plate. The second fluid passage is optionally sealed from the first fluid volume by providing a weld around the second fluid port. The port optionally comprises an annular flange formed by pressure forming an annular region around the port in at least one of the separator plate and the metal support plate. The stack of rectangular planar electrochemical cell units according to claim 13.

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