Cell stack and cell stack assembly

Abstract

The electrochemical cell stack (12) comprises a plurality of stacked cell units (10) each defining an outer periphery, a housing (58) surrounding the stack (12) to define a volume around the periphery, and at least one electrically insulating beam (76) extending generally in a stacking direction of the stacked cell units (10), extending across the plurality of cell units (10) and positioned between the periphery and the housing (58), wherein an electrical connection member (54) of a current delivery system of the cell stack extends within the electrically insulating beam (76).

Description

Technical Field

[0001] The present invention relates to an improved cell stack, a cell stack assembly including one or more such cell stacks, and a method for manufacturing the same. More specifically, the present invention relates to stacks of fuel cells or electrolysis cells, generally known as electrochemical cell units, which may be based on various battery chemistries such as solid oxide or PEM, and in particular to metal-supported solid oxide fuel cells (MS-SOFC) or metal-supported solid oxide electrolysis cells (MS-SOEC). The present invention also relates to an assembly including such a fuel cell or electrolysis cell.

Background Art

[0002] Electrochemical fuel cells use an electrochemical conversion process that oxidizes fuel to generate electricity. They generally have a flat configuration and are generally formed into a multilayer fuel cell unit having internal manifold fluid passages between an upper layer and a lower layer. Such fuel cell units are arranged in a stack configuration so as to overlap each other, for example, 10 to 200 fuel cell units are arranged in one stack, and fluid passages are provided between the stacked cell units. Other fuel cells may instead use external manifold flow paths for fuel and oxidant.

[0003] Each fuel cell unit operates to generate electricity during operation.

[0004] The technology behind solid oxide fuel cells (SOFC) is based on a solid oxide electrolyte that conducts negative oxygen ions from the cathode to the anode on the other side of the electrolyte. For this reason, fuel or reformed fuel contacts the anode (also known as the fuel electrode) of the fuel cell unit, and an oxidant such as air or an oxygen-rich fluid contacts the cathode (also known as the air electrode) of the fuel cell unit. The fluid passages inside and between the cell units make this possible. There are also other forms of electrochemical cell units.

[0005] Conventional ceramic-supported (e.g., anode-supported) SOFCs have low mechanical strength and are prone to breakage. Therefore, metal-supported SOFCs, which have an active fuel cell component layer supported on a metal substrate, have been developed. In these metal-supported solid oxide fuel cells, the ceramic layer can be very thin, as it performs not only structural strengthening functions but also electrochemical functions. Stacks incorporating such metal-supported SOFC stacks are generally more robust than ceramic-supported SOFCs and can generally be manufactured at a lower cost. WO2020 / 126486 and WO2015 / 136295 both disclose exemplary prior art configurations of such metal-supported SOFCs, and examples from them are shown in Figures 1-7 of this application to aid in explaining the operation of the stack. However, the present invention can be applied to all forms of electrochemical cell units.

[0006] Solid oxide electrolytic cells (SOECs) are another form of electrochemical cell. They may have the same structure as SOFCs, but essentially operate in reverse or regenerative mode, achieving the electrolysis of water and / or carbon dioxide by using a solid oxide electrolyte to produce hydrogen gas and / or carbon monoxide and oxygen. [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention is directed toward a stack of repeating electrochemical cell units that may have a structure suitable for use as an electrolytic cell or fuel cell. For convenience, the electrochemical cell units in the stack will be referred to below as “cell units.” These may be for use in power generation or in regenerative mode (i.e., including either or both SOEC or SOFC units, or other forms of electrochemical cell units).

[0008] Designing cell units and stacks presents significant mechanical, electrical, and thermal challenges because they must maintain consistent internal electrical connections to prevent electrical spikes or arcs from occurring within the stack. This can stem from the presence of fuel and oxidizer fluids in the stack. It is also crucial to define and separate fluid passages for fuel and oxidizer in the cell units and stack, as this is essential to achieve permanent fluid seals both within and between cell units and throughout the stack, and to prevent mixing of fuel and oxidizer within the stack. Furthermore, in some applications, such as in automotive applications, where repeated power increases and decreases or large movements occur, significant thermal cycles occur in the fuel and / or electrolytic cells. Therefore, the design must ensure a consistent manufacturing process and structural integrity of the stack assembly during long-term use. [Means for solving the problem]

[0009] According to a first aspect of the present invention, an electrochemical cell stack, Each of the stacked cell units defines the outer perimeter, A housing surrounds the stack to define the volume around the outer periphery, At least one electrically insulating beam extends generally in the stacking direction of the stacked cell units, extends across multiple cell units, and is positioned between the outer periphery of the cell units and the housing, The electrical connection members of the current delivery system of the cell stack extend into the interior of the electrically insulating beam. An electrochemical cell stack is provided.

[0010] Examples of electrochemical cell stacks include fuel cell stacks and electrolytic cell stacks.

[0011] This aspect of the present invention helps to reliably protect the current collection circuit from electrical contact with the cell unit and minimize the risk of short circuits within the cell stack. It should be noted that electrical connecting members are (usually) conductive, as are the housing and cell unit, and that direct contact between them can cause electrical short circuits, especially in metal-supported types. Such electrical short circuits are prevented by having an electrical insulating beam (i.e., a non-conductive component) around the electrical connecting members.

[0012] Furthermore, the beam can provide additional beneficial functions during stack assembly and subsequent use of the stack. Since the beam is located between the outer periphery of the cell unit and the housing, it can be positioned to engage with the outer periphery of at least some of the cell units during and after assembly, thus providing an alignment function for the cell units during, after, and in use.

[0013] In some embodiments, one or more beams can be used to eliminate the need for alignment members during the assembly process, which must be removed at a later stage of the assembly process.

[0014] In some embodiments, there are at least two electrically insulated beams, and an electrical connecting member (e.g., a rigid, conductive, elongated) of the current delivery system of the cell stack extends into at least one of these beams.

[0015] In some embodiments, each electrical connection member extending into one of the electrically insulated beams extends along the entire length of the beam, i.e., in the stacking direction of the stacked cell units.

[0016] In some embodiments, a beam or each beam may be formed of two or more parts, for example, an upper part and a lower part. In some embodiments, each part extends generally in the stacking direction of the stacked cell units, extends across multiple cell units, and is positioned between the outer periphery of the cell units and the housing. Electrical connection members of the current delivery system of the cell stack may extend into the interior of each part of the electrically insulating beam. In some embodiments, each part may be positioned to engage with the outer periphery of at least some of the cell units. In some embodiments, each part provides a cell unit alignment function both during and after assembly.

[0017] In some embodiments, the beam or each beam comprises two parts, namely an upper part and a lower part, the upper part stacked on top of the lower part, and electrical connection members extending through both parts.

[0018] In some embodiments, the length of a beam or each beam can be adjusted, for example, by providing one or more stepped surfaces between adjacent parts, or by providing tapered surfaces, or by providing additional parts.

[0019] In some embodiments, slots are provided in the beam or each part of the beam, so that after an electrical connector is fitted through the part of the beam, one or more other parts of the beam can be fitted around the electrical connector to extend the beam.

[0020] In some embodiments, a beam or each beam has one or more notches to increase fluid flow in its region, for example, to allow more airflow and result in greater cooling. The notches may be in a one-piece beam or in a multi-part beam, in which case the notches are in one or more parts of the multi-part beam.

[0021] In some embodiments, the cell unit includes a solid oxide fuel cell (SOFC).

[0022] In some embodiments, the cell unit includes a solid oxide electrolysis cell (SOEC).

[0023] In some embodiments, the cell unit includes one or more other suitable types of electrochemical cells.

[0024] In some embodiments, the cell and / or cell unit is generally flat plate shaped.

[0025] The cell unit may be, for example, electrode or electrolyte supported, or metal supported, in which case the electrochemically active layer may be provided or coated on a porous or perforated metal structure.

[0026] The cell unit may define a first fluid passage inside the cell unit, for example, between the upper plate and the lower plate of each cell unit.

[0027] The cell unit may define a second fluid passage between adjacent cell units.

[0028] The cell unit may be flat or flat plate shaped.

[0029] The housing can be a stack housing that defines a fluid volume for accommodating a stack of cell units. Alternatively, the housing can be a skirt of the stack housing. The skirt can be welded to the upper end plate and the lower end plate of the stack housing.

[0030] The housing or skirt may be associated with only a single stack (which it surrounds), and further, the beam may be associated with only a single stack and not between separate stacks (extending in the stack direction).

[0031] In some embodiments, an electrical connection member extending into the interior of an electrically insulating beam is an electrical connection member specifically for the stack, for delivering current from a current collector plate provided for the stack.

[0032] In some embodiments, the stack may have more than one such dedicated electrical connection member.

[0033] In some embodiments, the stacked cell units are electrically arranged in series throughout, with current collector plates provided at each end of the stack.

[0034] In some embodiments, the stacked cell units are arranged in both series and parallel configurations, with current-collecting plates provided at each pole of the stack.

[0035] In some embodiments, electrical connection members in the form of busbars extend from some or all of the current collection plates to one or more end plates of the stack housing. Preferably, the end plates are located at one end (or both ends) of the cell stack.

[0036] In some embodiments, the insulating beam, which is preferably a mica or ceramic tube, extends to at least one of the top or bottom of the stack of cell units, or to the inner surface of the end plate of the stack housing.

[0037] In some embodiments, the beam contacts the outer periphery of at least two of the multiple cell units, exerting a force that resists the multiple cell units moving further toward the beam.

[0038] In some embodiments, the force is generated by a housing (or skirt) that directly or indirectly engages with the beam, exerting a force that presses or biases the beam into the cell unit, or presses or biases the beam between the housing and the cell unit, thereby constraining or positioning the cell unit to resist movement of the cell unit relative to the housing and / or beam.

[0039] Preferably, the outer periphery of all cell units of the plurality of cell units is in contact with the electrically insulating beam.

[0040] Electrical connection members extending into the beam can be busbars connected to the stack's connection plates, or several other components of the cell stack's current delivery system. For example, this may include studs or cables connected to the busbars or current collection plates.

[0041] In some embodiments, the electrical connection members extend beyond the beam, pass through the top or bottom of the stack, and exit the housing, for example, through the end plates of the stack housing.

[0042] In some embodiments, an additional conductor is connected to the electrical connection member, and this additional conductor extends outside the housing.

[0043] Some embodiments have additional components for extending the current delivery system outside the housing.

[0044] According to a second aspect of the present invention, an electrochemical cell stack, Each of the stacked cell units defines the outer perimeter, A housing surrounds the stack, enclosing the volume around the outer perimeter, Each of the at least two electrically insulating beams extends across multiple cell units and engages with the outer periphery of at least two of the multiple cell units, Equipped with, The beam defines a line extending between the two beams, and the line defines a transverse line across each cell unit. a) The contact tangents between each beam and each of the plurality of cell units cooperate to resist the movement of each of the plurality of cell units in both lateral directions along the defined transverse line of the cell unit and in at least one longitudinal direction that is generally perpendicular to the transverse line and generally plane with respect to the outer circumference of each cell unit, or b) The contact tangents between each beam and each of the cell units cooperate in each beam to resist the movement of each of the cell units in both at least one transverse direction along the defined transverse line of the cell unit and at least one longitudinal direction that is generally perpendicular to the transverse line and generally plane with respect to the outer perimeter. An electrochemical cell stack is provided which is either or both of the above.

[0045] By resisting the movement of multiple cell units in either lateral direction along the defined horizontal line of a cell unit, a cell unit cannot move to the left or right relative to the central vertical plane of the stack.

[0046] By resisting the movement of each of the multiple cell units in at least one vertical direction that is generally perpendicular to the horizontal line and generally plane relative to the outer perimeter of each cell unit, the cell unit cannot move forward (or backward, depending on the constrained direction) along the central vertical plane of its stack.

[0047] By resisting the movement of each of multiple cell units in at least one lateral direction along the defined horizontal line of the cell unit, the cell unit cannot move to the left or right (depending on the constrained direction) relative to the central vertical plane of the stack.

[0048] Such movement constraints are beneficial because they minimize the relative movement of components within the stack, reducing the possibility that such movement could break seals between neighboring components or that shocks or vibrations applied to the stack could cause elements to shift from their intended positions.

[0049] In some embodiments, the beam extends across the entire height of the fuel cell stack.

[0050] In some embodiments, the electrical connection members of the current delivery system of the cell stack extend into one or both of the beams.

[0051] In some embodiments, the beam contacts at least 50% of the cell units in a stack of cell units. In other embodiments, the beam contacts all of the multiple cell units. In yet another embodiment, the beam contacts more than 50% of the cell units in a multiple cell unit.

[0052] If the edges of the cell units are not perfectly aligned throughout the entire stack, some cell units may not make contact with the beam.

[0053] The lines between beams are typically lines extending from the center of the beam's cross-section or from the furthest end of the beam in the direction of the airflow (or oxidizer flow) through the fuel cell stack.

[0054] Typically, the shapes of the two beams coincide. In some embodiments, they are mirror images of each other across the width of the cell unit.

[0055] This second aspect of the present invention may similarly have the features of the first aspect of the present invention, and vice versa. In particular, the electrical connecting members (e.g., rigid conductive elongated) of the current delivery system of the cell stack may extend into the interior of the beam.

[0056] According to a third aspect of the present invention, an electrochemical cell stack, Each of the stacked cell units defines the outer perimeter, A housing surrounds the stack, enclosing the volume around the outer perimeter, Two opposing electrical insulating plates are positioned between the housing and the multiple stacked cell units, each in contact with one of the two opposing sides of the multiple stacked cell units, An electrically isolated beam extending across multiple cell units in a stack and engaging with the outer periphery of those multiple cell units, The insulating beam also engages with either or both of the housing and one of the electrical insulating plates. Electrochemical cell stacks are also provided.

[0057] The engagement of both the cell unit and the housing or electrical insulating plate ensures that all components are automatically and correctly aligned in the stack during assembly. This allows any suitable fluid passage within the cell unit itself to properly form, for example, the flow of fuel or oxidizer. Furthermore, the edges of the cell units are prevented from coming too close to each other, reducing the possibility of electrical short circuits between cell units in the stack.

[0058] In some embodiments, the electrical connection members of the current delivery system of the cell stack extend into one or both of the beams.

[0059] In some embodiments, there are at least two electrically isolated beams, each extending across multiple cell units.

[0060] In some embodiments, the second beam engages with the outer periphery of each of the plurality of cell units and also engages with the housing and / or one of the electrical insulating plates.

[0061] In some embodiments, each beam engages with the outer periphery of a plurality of cell units and also engages with the housing and / or one of the electrical insulating plates.

[0062] In some embodiments, each beam is formed integrally with one of the electrical insulating plates. However, more generally, they are separate components.

[0063] Each electrical insulating plate that engages with the edge of the cell unit has a cell engagement surface that provides engagement. In some embodiments, the beam closest to one of the cell engagement surfaces of the electrical insulating plates has a cell engagement surface that extends distal to the cell engagement surface of that electrical insulating plate, i.e., away from there toward the central longitudinal plane of the stack, for example toward a recess in the edge of the cell unit, or partially across each end of the cell unit. In a preferred embodiment, two beams each have a cell engagement surface that extends distal to the cell engagement surface of the nearest electrical insulating plate. The distal arrangement of the cell engagement surfaces of the two beams results in a narrowing of the width of the cell unit between the two beams compared to the width between the two electrical insulating plates. This narrowing results in a concentration of airflow through the central stream of the second fluid passage due to the narrowing between the beams, and less airflow to the sides of the second fluid passage in the space of the side of the central stream corresponding to the portion of the second fluid passage adjacent to the two sides of the cell unit where the electrical insulating plates are located.

[0064] In some embodiments, the two beams are positioned at or near the downstream end of the second fluid passage, or at or near the downstream end of the oxidizer-carrying fluid passage, which is the same end in a parallel flow configuration. The oxidizer-carrying downstream end is typically the hot end of the cell stack, and having a constriction at least at that end helps to concentrate the oxidizer flow (i.e., airflow) at that hot end, assisting the need to increase the fluid flow to provide the necessary cooling. In other words, the flow density at that hot portion of the cell stack can be increased.

[0065] In the case of four beams, they can be placed at both ends of the fluid passage.

[0066] Each electrical insulating plate may also engage with the inner wall of the housing, but in some embodiments, the configuration may include two or more electrical insulating plates, i.e., stacked electrical insulating plates, between each opposing side of a plurality of stacked cell units.

[0067] In some embodiments, the electrical insulating plates are located only on two of the sides of the stacked cell units, preferably parallel and opposing sides, more preferably on the long side of the cell unit, i.e., there are no such electrical insulating plates in contact with the outer periphery of the stacked cell unit at the proximal and distal ends (with respect to the direction of airflow / oxidant flow) of the stacked cell unit.

[0068] In some embodiments, more than one electrical insulating plate is arranged side-by-side or stacked in a common plane relative to each of the opposing sides of the stacked cell units.

[0069] A third aspect of the present invention further features one or more features of the first or second aspect of the present invention, and vice versa. In particular, the electrical connecting members (e.g., rigid conductive elongated) of the current delivery system of the cell stack may extend into the interior of the beam.

[0070] A fourth aspect of the present invention provides a cell stack assembly comprising the cell stack as defined above, a fuel delivery port connected to a first fluid passage in the cell stack, an oxidizer delivery port connected to a second fluid passage in the cell stack, a current collector plate for collecting or delivering current from the cell stack, and an electrical connecting member for delivering current from the current collector plate to or from the housing.

[0071] A fourth aspect of the present invention further features one or more features of any one or more of the first, second, or third aspects of the present invention, and vice versa.

[0072] According to a fifth aspect of the present invention, an electrochemical cell stack assembly, Each of the stacks of cell units defines the outer perimeter, The periphery of the stacked cell units, which define the volume around the outer periphery, is initially divided into at least two separate parts: a housing and a housing. At least two electrically isolated beams, The system comprises one electrically insulating beam assembled between one end of the housing and a stacked cell unit, a second electrically insulating beam assembled between the second end of the housing and a stacked cell unit, and at least two electrically insulating beams each extending across multiple cell units and contacting the outer periphery of at least two of the multiple cell units, thereby exerting a force that resists further movement of the multiple cell units toward the beams. The first and second initial parts of the housing are separate parts, and when the two parts of the housing are closed together, they clamp at least two beams to the outer periphery of at least two of the multiple cell units. An electrochemical cell stack assembly is provided.

[0073] Typically, two separate parts are not initially connected to each other.

[0074] Preferably, at least two parts of the housing are welded together in a clamped state to maintain the clamping force.

[0075] A fifth aspect of the present invention further features one or more features of any one or more of the first, second, third, or fourth aspects of the present invention, and vice versa. In particular, the electrical connecting members (e.g., rigid, conductive, elongated) of the current delivery system of the cell stack may extend into the interior of the beam.

[0076] According to a further aspect of the present invention, an electrochemical cell stack, Each of the stacked cell units defines the outer perimeter, At least one electrically isolated beam extending generally in the stacking direction of the stacked cell units and extending across multiple cell units, Equipped with, The electrical connection members of the cell stack's current delivery system extend into the interior of the electrically insulating beam. A beam, or each beam, is formed from two or more parts. An electrochemical cell stack is provided.

[0077] According to a further aspect of the present invention, an electrochemical cell stack, Each of the stacked cell units defines the outer perimeter, At least one electrically isolated beam extending generally in the stacking direction of the stacked cell units and extending across multiple cell units, Equipped with, The electrical connection members of the cell stack's current delivery system extend into the interior of the electrically insulating beam. Each beam or beam has one or more notched areas to increase fluid flow in its region. An electrochemical cell stack is provided. This beam can be divided into one or more parts.

[0078] In these further embodiments, the embodiments may also follow any of the embodiments described above, and for a beam or each beam, there may be a first part, which is usually an upper part, and a second part, which is usually a lower part. In some embodiments, there is a third part. Further parts may also be present.

[0079] In some embodiments, each part generally extends in the stacking direction of the stacked cell units, extends across multiple cell units, and is positioned between the outer periphery of the cell units and the housing of the stack. Electrical connection members of the current delivery system of the cell stack may extend into the interior of each part of the electrically insulating beam. In some embodiments, each part can be positioned to engage with the outer periphery of at least some of the cell units. In some embodiments, each part provides a cell unit alignment function both during and after assembly.

[0080] In some embodiments, a beam, or each beam, comprises two parts, namely an upper part and a lower part, with the upper part stacked on top of the lower part, and electrical connection members extending through both parts.

[0081] In some embodiments, the length of a beam or each beam can be adjusted, for example, by providing one or more stepped or castrated surfaces between adjacent parts, or by providing tapered or chamfered surfaces.

[0082] In some embodiments, slots are provided in the sidewalls of the beam or one or more parts of each beam. This allows for the insertion of one or more other parts of the beam around the electrical connector to extend the beam, for example, after an electrical connector has been fitted through one or more parts of the beam, and access to the free end of the electrical connector has been restricted.

[0083] In some embodiments, a beam or each beam has one or more notched areas to increase fluid flow in that region, for example, to allow more airflow and result in greater cooling. The notched areas may be in a one-piece beam or in a multi-part beam, in which case the notched areas are in one or more parts of the multi-part beam.

[0084] The cell stacks and cell stack assemblies of the present invention may be used in household, industrial, commercial, or transportation / vehicle applications. One such application is provided, which includes a fuel cell system comprising an electrochemical cell stack as defined for use in a vehicle application.

[0085] According to a sixth aspect of the present invention, a method for assembling an electrochemical cell stack, To provide stacked cell units that define the outer perimeter, To provide at least one electrically isolated beam that extends across multiple stacked cell units and is assembled to the stacked cell units so as to engage with the outer periphery of those multiple cell units, Fitting the housing around the stacked cell units and the electrically insulating beam, Includes, The housing defines a volume around its outer periphery, and the housing is initially divided into at least two separate parts. The first and second initial separate parts of the housing, when the two parts of the housing are closed together, clamp against the outer periphery of at least two of the multiple cell units, exerting a force that resists further movement of the multiple cell units toward the beam, and then the initial separate parts are connected or joined to each other in a clamped state to maintain the clamping force by the beam toward the outer periphery of at least two of the multiple cell units. A method is provided.

[0086] In some embodiments, there are at least two electrically isolated beams, One electrically insulating beam is assembled between the first initial part of the housing and the stacked cell units, and a second electrically insulating beam is assembled between the second initial part of the housing and the stacked cell units, and at least two electrically insulating beams each extend across multiple cell units and abut against the outer periphery of at least two of the multiple cell units, exerting a force that resists further movement of the multiple cell units toward the beams. The first and second initial separate parts of the housing, when the two parts of the housing are closed together, clamp against the outer periphery of at least two of the multiple cell units, exerting a force that resists further movement of the multiple cell units toward the beam, and then the initial separate parts are connected or joined to each other in a clamped state to maintain the clamping force by the beam toward the outer periphery of at least two of the multiple cell units.

[0087] In some embodiments, the first and second initial parts of the housing are separate components that are indirectly clamped to the outer periphery of at least two of the multiple cell units via an electrical insulating beam or, in addition to each electrical insulating beam, one or more electrical insulating plates.

[0088] In some embodiments, one or more beams engage with the outer periphery at a recess on the outer periphery.

[0089] A fuel or electrolytic cell stack of a method according to a sixth aspect of the present invention is a fuel or electrolytic cell stack of any one of the first to fifth aspects of the present invention, and may include any one or more preferred or optional features of the first to fifth aspects of the present invention. In particular, the electrical connecting members (e.g., rigid conductive elongated) of the current delivery system of the cell stack may extend into the interior of the beam.

[0090] In some embodiments, the beam is a circular beam.

[0091] In some embodiments, the beam is a tube.

[0092] In some embodiments, the busbars of the cell stack extend into at least one of the beams, for example, to the center of the beam.

[0093] In some embodiments, there are two busbars in the stack, each located on one of the beams.

[0094] In some embodiments, the beam consists of mica.

[0095] In some embodiments, two opposing electrical insulating plates are positioned between the housing and the stacked cell units, each facing one of the two opposing sides of the stacked cell units, and an insulating beam is applied to the electrical insulating plates.

[0096] In some embodiments, the beam also contacts one of the electrical insulating plates.

[0097] In some embodiments, the beam also contacts the housing.

[0098] In some embodiments, the beam extends across the entire height of the stack.

[0099] In some embodiments, each beam is in contact with each cell unit.

[0100] In some embodiments, each beam defines a barrier to the fluid flow entering and leaving the second fluid passage. This can be facilitated by blocking or reducing the fluid flow around the outside of the beam between the outer periphery and the housing, and by directing more fluid flow towards the central stream of the second fluid passage.

[0101] In some embodiments, each beam defines a barrier to the fluid flow entering and leaving the second fluid passage, thereby concentrating the airflow through the central stream of the second fluid passage and reducing the airflow to the sides of the second fluid passage adjacent to the linear sides of the cell unit. This may be beneficial in some embodiments to provide more flow to the hotter portions of the cell.

[0102] In some embodiments, the outer circumference includes two straight sides and a shaped end.

[0103] In some embodiments, the beam is positioned at one of the shaped ends.

[0104] In some embodiments, the beam is seated in a recess or depression formed on the straight side of its outer circumference, the recess or depression preferably having a shape complementary to the shape of the beam, i.e., the portion of the beam into which it fits or contacts.

[0105] In some embodiments, the cell unit is generally rectangular.

[0106] In some embodiments, beams exist along each long side of the rectangle.

[0107] In some embodiments, beams are located at or adjacent to two of the corners of a rectangle.

[0108] In some embodiments, the two corners are adjacent corners.

[0109] In some embodiments, the two corners are adjacent corners located at the end of one of the shorter sides of the rectangle.

[0110] In some embodiments, the two corners are located at the downstream end of a second fluid passage of a stacked cell unit, or a fluid passage of airflow / oxidant flow, which defines a longitudinal direction perpendicular to the transverse line across the fluid passage and generally planar with the outer circumference of at least one of the cell units.

[0111] In some embodiments, the direction of fluid flow through the first fluid passage or fuel flow fluid passage corresponds to the direction of fluid flow through the second fluid passage, i.e., the stacked cell units employ a parallel flow configuration for the fluids flowing through the stacked cell units. Alternatively, there may be a counterflow configuration in which the direction of fluid flow through the second fluid passage is opposite to the direction of fluid flow through the first fluid passage. In other configurations, the flows may be at other angles to each other, for example, 90 degrees to each other.

[0112] In some embodiments, there are three or four beams.

[0113] In some embodiments, each cell unit has two linear sides that house two beams, respectively.

[0114] In some embodiments, the cell unit has two or four corners, each corner having one of the beams.

[0115] In some embodiments, different portions of the outer periphery define recesses or indentations where each beam is seated.

[0116] In some embodiments, each corner has a recess or indentation for accommodating one of the beams.

[0117] In some embodiments, the recess or indentation is located in the center of the side of each cell unit.

[0118] In some embodiments, the recess or indentation wraps around the beam over at least a 90-degree segment.

[0119] In some embodiments, the recess or indentation wraps around the beam over at least 180-degree segments.

[0120] In some embodiments, the recess or indentation has a curved wall.

[0121] In some embodiments, the recess or depression is a recess comprising two or more straight wall portions against which a beam is pressed, the straight wall portions being angled relative to one another in each recess or depression.

[0122] In some embodiments, the beam extends perpendicularly across the cell unit, i.e., parallel to the longitudinal direction of the stack or the stack height direction.

[0123] In some embodiments, the outer perimeters of all cell units are aligned with one another along the entire circumference.

[0124] In some embodiments, the housing has a bottom and a top, and a skirt that surrounds the outer periphery of the cell unit.

[0125] In some embodiments, the skirt is formed of at least two parts that are joined together at their seams, for example by welding.

[0126] In some embodiments, the housing is provided with separate top and bottom components, and the skirt is joined to these top and bottom components, for example, by welding.

[0127] In some embodiments, each stacked cell unit comprises a separator plate and a metal support plate, the separator plate and the metal support plate overlapping each other. One or more first fluid passages extend through the cell unit between the respective separator plate and metal support plate of each cell unit, The stacked cell units are equipped with a second fluid passage extending between adjacent cell units. The first and second fluid passages are for distributing fuel and oxidizer through the stack.

[0128] In some embodiments, the stack contains active cell units and inactive cell units.

[0129] In some embodiments, each active cell unit has one or more cell chemical layers provided on a porous or perforated region of the metal plate of the cell unit.

[0130] In some embodiments, the cell chemical layer comprises a plurality of layers, including an anode layer, an electrolyte layer, and a cathode layer.

[0131] In some embodiments, each cell unit is provided with at least one fluid port, and the fluid ports of adjacent cell units are aligned with and communicate with the first fluid passage of each cell unit.

[0132] In some embodiments, the cell unit includes a separator plate with molded outward projections to partially separate adjacent cell units in order to define a second fluid passage between them.

[0133] In some embodiments, outward-facing projections of the first cell unit engage with the outer surface of the cell chemical layer of an adjacent cell unit at their ends.

[0134] In some embodiments, the cell unit includes a metal support plate having a molded port feature formed around its port, the molded port feature extending toward a separator plate of the cell unit, and the elements of the molded port feature are spaced apart from each other to define a fluid path from the port to the elements, thereby enabling the passage of fluid from the port to a first fluid passage within the cell unit between the metal support plate and the separator plate.

[0135] In some embodiments, each cell unit is flat.

[0136] In some embodiments, each cell unit has at least one recess on at least one edge, and these recesses are aligned across the width or length of the cell unit.

[0137] In some embodiments, the recess is configured to be at least partially coincide with and contact the opposing portion of an adjacent electrically insulating beam or tube.

[0138] In some embodiments, the electrically insulating beam is positioned between the housing and the outer circumference of the cell unit, in contact with them, so as to obstruct or close off the fluid flow path between the electrically insulating beam and the housing or its skirt.

[0139] In some embodiments, two of the electrically isolated beams are positioned adjacent to an internal manifold fluid port or fluid outlet port and act to define, limit, or restrict the fluid flow path to the internal manifold fluid port or fluid outlet port at the point where the beams contact the outer periphery of the cell unit.

[0140] In some embodiments, each cell unit has at least one recess on at least one edge into which one of the electrically insulating beams is assembled, and at least one recess has a shape opposite to the portion of the electrically insulating beam assembled within the recess (each recess of adjacent recesses is aligned to define a recessed channel extending in the stacking direction).

[0141] According to a further aspect of the present invention, a method for assembling an electrochemical cell stack, To provide cell units that define the outer perimeter of each, To provide at least one electrically insulating beam assembled to a cell unit such that the electrically insulating beam extends across a plurality of stacked cell units and engages with the outer periphery of each of the plurality of cell units, with the electrical connection members of the cell stack's current delivery system extending into the electrically insulating beam. Includes, The first part of the electrical insulation beam is fitted onto the electrical connection member, the cell unit is stacked in contact with the first part of the electrical insulation beam, and then the second part of the electrical insulation beam is fitted onto the electrical connection member and the first part of the electrical insulation beam. A method including this is provided.

[0142] This method can be combined with any one or more other embodiments of the present invention.

[0143] In some embodiments, the beam, or each beam, is formed from just two separate parts. In some embodiments, the beam is formed from three or more separate parts.

[0144] In some embodiments, the beam or each beam has one or more notched areas to increase fluid flow in that region within the stack.

[0145] In some embodiments, the length of a beam or each beam can be adjusted, for example, by providing one or more stepped or castrated surfaces between adjacent parts, or by providing tapered surfaces.

[0146] In this aspect of the present invention, the method includes first installing the first and second parts of the beam in a shortened configuration on their respective electrical connectors, then connecting the tops of the electrical connectors to the upper electrical connectors, and subsequently extending the beam to a further extended length. Alternatively, if the beam is initially installed to a further extended length, access to the tops of the electrical connectors may be blocked by the upper current collector plate located at the top of the stack of cell units, by the tops of the beam, or both.

[0147] In some embodiments, the length of the beam is adjusted to fit under the upper current collector plate.

[0148] In some embodiments, slots are provided in the sidewalls of the beam or one or more parts of each beam. This allows for the insertion of one or more other parts of the beam around the electrical connector to extend the beam, for example, after an electrical connector has been fitted through one or more parts of the beam, and access to the free end of the electrical connector has been restricted.

[0149] In some embodiments, the beam or each beam has one or more notched areas to increase fluid flow in that region within the stack.

[0150] Those skilled in the art will understand that each feature of each embodiment can be used individually or in combination with other features of each embodiment, and similarly by each of the other embodiments.

[0151] These and other features of the present invention will be described in further detail here with reference to the accompanying drawings, using various simple examples. [Brief explanation of the drawing]

[0152] [Figure 1] This is an exploded view of a conventional cell unit, where two cell units are arranged as a vertical stack. [Figure 2] This is an exploded view of a conventional cell unit, where two cell units are arranged as a vertical stack. [Figure 3] This diagram shows the stack in its assembled form, as shown in Figure 2. [Figure 4] This figure shows a further modification of the cell unit, similar to Figure 1, but with separate metal cell components and a metal support plate. [Figure 5] This is an exploded view of an alternative conventional cell unit. [Figure 6] This figure shows a disassembled version of a conventional cell stack assembly, with some cell units removed for clarity. [Figure 7]This figure shows a conventional cell stack assembly in its assembled form. [Figure 8] This is a plan view of a first embodiment of the present invention, which includes four busbars and two electrical insulating beams extending upward from a current collection plate 52. [Figure 9] This figure shows a second embodiment of the present invention, which is similar to the first embodiment but is equipped with only two busbars extending upward from the current collection plate. [Figure 10] This figure shows a modified version of the cell stack in Figure 8, in which the shape of the corners of the cell unit has been changed, and four electrically insulating beams are provided, one at each corner. [Figure 11] This figure shows a further modification of the cell stack in Figure 8, with four electrically insulating beams, one at each corner, illustrating the configuration of parallel flow fuel and oxidizer (air). [Figure 12] Figure 11 is a perspective view of the cell stack without the four busbars. [Figure 13] This diagram shows the cell stack in Figure 12, which has four busbars. [Figure 14] This figure shows the cell stack in Figure 12 with a portion of the housing removed. [Figure 15] Figure 12 is a partial cutaway view of the assembly steps for assembling the housing around the stack of cell units in the cell stack. [Figure 16] Figure 12 is a partial cutaway view of the assembly steps for assembling the housing around the stack of cell units in the cell stack. [Figure 17] Figure 12 is a partial cutaway view of the assembly steps for assembling the housing around the stack of cell units in the cell stack. [Figure 18] This figure shows a further modification of the present invention, in which part of the housing has been removed. [Figure 19] This figure shows a further modification of the present invention, in which part of the housing has been removed. [Figure 20]This figure shows yet another further modification of the present invention, featuring a one-piece housing. [Figure 21] This figure shows a further modification of the present invention, comprising four 2-piece beams. [Figure 22] This figure shows a further modification of the present invention, comprising four two-piece beams, each having a stepped surface for varying the length of the beam. [Figure 23] This diagram shows the two beam pieces from Figure 22 in more detail. [Figure 24] This figure shows a further modification of the present invention, comprising four two-piece beams, each having a tapered surface for varying the length of the beam. [Figure 25] This diagram shows the two beam pieces from Figure 24 in more detail. [Figure 26] This figure shows a further modification of the present invention, comprising four three-piece beams, each consisting of a central first part and two outer parts, with each outer part having a slot for inserting the outer part after the central first part has been fitted around the electrical connection members of the stack. [Figure 27] This figure shows a further modification of the present invention, comprising four beams, the ends of which have notched areas to increase fluid flow in that region, for example, to allow more airflow and result in greater cooling. [Modes for carrying out the invention]

[0153] Referring first to Figure 1, a prior art configuration of a fuel cell unit 10 is shown, and two disassembled versions are shown to illustrate a possible internal structure of a fuel cell unit 12, which is arranged as a stack 12, with fluid passages accessible via ports 16 at each end formed in the central interior of the fuel cell unit 10. Details of this form of fuel cell unit 10 are described in depth in WO2020 / 126486, the entire contents of which are incorporated herein by reference. However, in short, each of these fuel cell units 10 in this example comprises two plates or layers in the form of an upper metal support plate 18 and a lower separator plate 20. The metal support plate 18 has an active fuel cell component layer 22 on it, and the separator plate 20 has a number of punched central protrusions and recesses 24 and further protrusions and recesses 36, along with a raised rim 26 for joining the separator plate to the underside of the metal support plate 18.

[0154] Figure 2 shows a modified fuel cell unit of Figure 1, in which additional protrusions and recesses 36 are provided around the ports 16 of the metal support plate 18 so as to face the additional protrusions and recesses around the ports 16 of the separator plate 20. Similarly, a raised rim is provided on the metal support plate so as to overlap a similar rim on the separator plate.

[0155] As can be seen by comparing Figure 1 and Figure 2, Figure 2 shows the underside of the plate, while Figure 1 shows the upper side. Therefore, a protrusion in Figure 1 is a recess in Figure 2, and vice versa. Thus, these terms are interchangeable.

[0156] Figure 2 also shows that the lower region of the metal support plate beneath the fuel cell component layer 22 comprises an array of perforations 30. These perforations allow access to both sides of the fuel cell component layer, even though the fuel cell component layer is formed on the metal support plate, and these are similarly present in the example in Figure 1.

[0157] Since the present invention can utilize similar cell unit structures, these exploded views, along with Figures 3 and 4, are useful in illustrating the possible internal configurations of the cell units of the present invention, although, as will be discussed later, the outer contour differs in typical embodiments of the present invention. Depending on the fluid flow requirements of the stack, additional or fewer ports 16 may be provided.

[0158] In each active fuel cell unit of the stack, the fuel cell component layer may be an electrochemically active layer, typically a metal (usually stainless steel) foil, deposited and supported on a metal support plate 18. The electrochemically active layer includes, as known in the art, an anode layer, an electrolyte layer, and a cathode layer, respectively. Additional layers, such as a cover layer or a control layer, may also be included, as known in the art.

[0159] Referring to Figure 3, the fuel cell unit 10 of Figure 2 is shown in an assembled configuration, where the metal support plate 18 and separator plate 20 of each fuel cell unit 10 are joined together around their edges. As can be seen in this cross-sectional view, the central projections and recesses 24 of the separator plate 20 define a first fluid passage 14 by maintaining the space between the two plates of each unit, and also define a second fluid passage 32 by maintaining a second space between adjacent fuel cell units 10. Gaskets 34 maintain the spacing at the ends of the fuel cell units 10 and overlap further projections or recesses 36 around the ports 16 of both the separator plate and the metal support plate. The gaskets 34 are annular, and therefore their central openings overlap the ports 16. Thus, a “chimney” or passage 38 is formed through the stack, which is sealed by the gaskets 34 from the second fluid passage 32 between adjacent fuel cell units 10, but leads to the first fluid passage 14 inside the fuel cell unit. Therefore, the fluid can enter and exit the first fluid passage through port 16. Alternatively, the fluid passing through the second fluid passage circulates around the outside of the fuel cell unit, as will be described in more detail below.

[0160] In Figure 4, the additional protrusions and recesses 36 are provided only on the separator plate as in Figure 1, and in some embodiments, it may be necessary to punch out longer / deeper protrusions / recesses so that they cannot be added. However, in this embodiment, the fuel cell component layer is instead deposited on an additional support plate 40 and bonded to the metal support plate 18 in a further step as further described in WO2020 / 126486, so that the thickness of the support plate 18 present as the fuel cell component layer can be further increased. As seen in Figure 4, instead an array of perforations is provided on the underside of that additional support plate.

[0161] Figures 1-4 are from WO2020 / 126486, while Figures 5-7 are from WO2015 / 136295. These show further possible configurations of conventional fuel cells. A stack of metal-supported SOFCs is again provided, and the operation is almost the same. However, instead of further protrusions and recesses on the separator plate, and instead of the metal support plate in the case of Figures 2 and 3, this example uses a spacer plate 42 between the metal support plate 18 and the separator plate 20. Furthermore, the separator plate 20 uses beams and grooves 24 instead of protrusions and recesses 24.

[0162] In this example, the spacer plate 42 has a central opening 44 that (when assembled) defines a first fluid passage 14 within the cell unit, and the central opening 44 connects to ports 16 of the separator plate 20 and the metal support plate 18 via a ventilation passage 46. Furthermore, the three plates 18, 20, and 42 also have additional ports 48 for ventilation to (or from) a second fluid passage 32 between adjacent fuel cell units 10, as described in WO2015 / 136295, the full contents of which are incorporated herein by reference.

[0163] Figure 6 shows multiple fuel cell units 10 of Figure 5 configured in a fuel cell stack 12. A dummy cell 48 is also shown, which may lack all the layers or perforations necessary to activate the fuel cell component layers, but otherwise appears complete as a consistent design configuration as known in the art. Furthermore, a current collector plate 52 for collecting the charge generated by the stack of fuel cell units 10 is shown.

[0164] To maximize the capture of that charge, fuel cell units are usually arranged electrically in series through a stack, with current collector plates at both ends of the series stack; however, fuel cell units in a stack can also (or instead) include units arranged in parallel, as known in the art, in which case current collector plates are appropriately positioned at both poles of those parallel stacks.

[0165] The current collector plate 52 can be connected to or formed integrally with one or more busbars 54 and / or terminals 56 (as shown in the current collector plate on the left in Figure 8) to carry current from there to the outside of the stack assembly. Such current collector plates 52, busbars, and terminals can be seen in Figures 6 and 8, and the terminals 56 can be seen in Figure 7 as extending to the outside of the stack assembly when the stack assembly is fully assembled.

[0166] When assembling the stack 12, multiple fuel cell units 10 are used, and the fuel cell units 10 are stacked one after another between two end plates 62. There are current collector plates 52 at both poles of the stack of fuel cell units, and an insulating plate 50 is placed between the current collector plates 52 and the end plates 62.

[0167] In Figure 6, the solid oxide fuel cell unit is compressed and held in place in the assembled stack using multiple (four shown) tie bars 64 that extend between two end plates 62 through guide holes 66 (see Figure 5) in three plates 18, 20, and 42 of the fuel cell unit 10. As can be seen in Figure 7, nuts at the ends of the tie bars 64 provide the compression. In other examples, compression can be pre-loaded and held by welding a skirt around the cell to the end plates. This latter technique is used in the examples of the present invention from Figure 9 onward, although compression bolts may be used instead; however, careful design consideration is required because the tie bars are close to the edges of the guide holes (i.e., the edges of the metal components defining the guide holes of at least one fuel cell stack), and there is a risk of short circuits between the tie bars and the stack when the components expand at high temperatures in a mixed atmosphere that may contain vapor, reacted and unreacted hydrocarbons and air; therefore, it is preferable to constrain with a skirt.

[0168] All of the above examples of conventional fuel cells are described as examples of one possible type of cell unit in which the features and advantages of the present invention can be used in a cell stack or cell stack assembly. Those skilled in the art will understand that further shapes of the cell unit, busbar / electrical takeoff designs, and housing shapes can also be used. Such further designs are described in the following description of exemplary embodiments of the present invention.

[0169] Referring now to Figure 8, one embodiment of the present invention is shown. In this cell stack assembly 12, the cell stack comprises a plurality of cell units 10 arranged as a stack inside a housing 58, in this embodiment the housing 58 is a skirt formed of two halves 68, 70 joined to each other at the long sides of the cell units 10. The joining may be a weld at a weld line 72 located in the center of the long side of the stack, as shown in Figure 8. It does not have to be in the center, but it is convenient to have it in the center for symmetry or for ease of manufacture and assembly, and this allows the two halves to be easily swapped during assembly. In an alternative version of Figure 10, the weld line 72 may be at the short end of the cell unit 10, in which Figure 10 the weld line 72 is shown in the center of the side of the cell unit 10, which is also optional but preferred for symmetry or for ease of manufacture and assembly.

[0170] The cell unit 10 is generally rectangular despite having molded corners 74, and the corners 74 can accommodate an electrically insulating beam such that the beam is positioned between the corners 74 and the housing or skirt 58. In these examples, the electrically insulating beam 76 takes the form of a circular or tubular molded beam with a central void, such as a pipe or tube as shown. In preferred examples, they are made of mica, but other electrically insulating materials, including many ceramics, can also be used, preferably a brittle electrically insulating material. In Figure 8, only two of the corners are equipped with beams 76. Both are located at the short end of the stack, which in this embodiment is the fluid outlet end of the stack, as shown in Figure 11. In some embodiments, only one beam 76 may be provided. In other embodiments, three, four, or more beams may be provided. Figure 10 shows four.

[0171] The example in Figure 8 shows four busbars or electrical connection poles 54, each making electrical contact with a current collector plate 52 at the bottom of the stacked cell unit 10. In this example, they are all common poles and therefore all collect current from that pole. Additional current collector plates may be provided on the opposite poles, and additional busbars or direct connectors may be used.

[0172] These busbars and any connectors connected to them allow the current generated by the stacked cell units 10 to be collected and distributed outside the stack, distal to the current collection plate, similar to the stack in Figure 6. Although four busbars 54 are shown in this example, it is possible to have only one busbar, or two (as in Figure 9), or any desired number of busbars, or to replace the busbars with other forms of electrical connection members or other forms of terminals.

[0173] In Figure 8, two busbars 54 are passed through the central holes of two beams 76, and are therefore surrounded by beams that insulate the busbars from the cell unit and housing. Since the busbars are conductive and usually made of stainless steel, and the housing / skirt and cell unit (which is metal-supported in this embodiment) are also made primarily of steel, insulating the busbars from them provides an advantage as it allows the components to be packed more compactly into the housing.

[0174] Next, referring to Figure 9, there are only two busbars. Similarly, as in Figure 8, there are two beams 76. In this embodiment, both busbars 54 are located within the beams 76.

[0175] In the example in Figure 9, the electrically insulating beams 76 are located at two corners 74 of the stack. There are no such beams at the other two corners 74. As illustrated, each beam is specific to its stack and engages with the stack along substantially its entire length (if not its entire length).

[0176] In these embodiments, the housings facing these beams 76 are chamfered. Thus, the long sides of the housings are joined to the short sides of the housings by angled chamfers 90 so that the housings 68, 70 abut the beams 76 with a net force oblique to the cell units 10. This helps to keep the cell units 10 in their proper positions and prevents them from shifting when the stack 12 is subjected to vibration or other shocks during use or transport.

[0177] Electrical insulating plates 78 are also provided along the long sides of the cell unit 10. In Figure 9, as in Figures 8 and 10-17, these electrical insulating plates 78 extend along the long sides of the cell unit 10 and contact the starting point of the chamfer 90 at their ends. In other examples, they only extend partway along the long sides of the housings 68, 70. For example, there may be multiple electrical insulating plates 78 along each long side. For example, there may be multiple electrical insulating plates 78 separated by one or more beams 76, as shown in Figure 20. As in Figure 20, this may be a single beam 76 in the center of the side.

[0178] In the alternative embodiment shown in Figure 20, the beam 76 has a rectangular cross-section rather than a circular one, but it should be noted that other shapes are also possible, as will be easily understood by those skilled in the art.

[0179] Returning to Figure 9, the molded corner 74 of the cell unit 10 is shown to have a curved shape with a concave curve on either side of a convex curve, the concave curve being molded to follow the adjacent contour of the beam 76 on which it sits. In this embodiment, the curved shape coincides and aligns perpendicularly with all cell units in the stack. By thus following or coinciding with the shape of the beam, multiple contact points (or a long, single continuous contact line) can be achieved between the beam 76 and the corner 74 of the cell unit 10 (in fact, in a preferred configuration of all cell units 10). In particular, it is preferable that the beam closely abuts and engages with the cell unit. This reduces the point load on the cell unit 10 and helps to grip or otherwise control the cell unit (e.g., through the oblique load described above) to resist the movement of the cell unit during the operation of the stack assembly. In Figure 9, the convex curve follows the circumference of the circular beam over a segment of approximately 90 degrees. In Figure 19, on the other hand, this follows approximately 180 degrees, i.e., a semicircle of the beam. This latter configuration does not generate a net oblique holding force, but instead, by sufficiently enveloping the beam, it holds the beam against longitudinal movement in both directions (forward or backward) in addition to holding it laterally (towards the beam).

[0180] Figure 10 shows an alternative configuration in which the corner 74 instead has two perpendicular sides, i.e., a square or rectangular cutout. Thus, a square or rectangular beam may be used to match its shape, but in this embodiment, the beam 76 still maintains its circular (tubular) cross-section. In this alternative configuration, the beam 76 still has multiple (two) contact points with the corner / recess 74. Thus, there are two tangents between the corner 74 and the beam 76, which still impart a net oblique force to the cell unit 10. These still grip the cell unit by the beam to resist movement of the cell unit in use, i.e., movement in both the lateral and longitudinal directions.

[0181] Next, referring to Figure 20, a rectangular recess is provided in the center of the two sides, and a rectangular beam is used. Thus, the cell unit 10 is also gripped by the beam 76 to resist movement of the cell unit 10 in use, i.e., to resist movement in both the lateral and longitudinal directions. However, here, the rectangular recess, as shown in Figure 19, wraps around the beam sufficiently to hold the beam against longitudinal movement in both directions (forward or backward) in addition to lateral holding (towards the beam).

[0182] Furthermore, when fitting the beam 76 into the recess of the corner or side of the cell unit 10 between the cell unit and the housing 58, a person skilled in the art will understand that many different shapes of the recess of the corner 74 or other locations where recesses are provided, as well as the shape of the beam 76, are suitable.

[0183] Furthermore, the beam 76 does not need to be located at a corner or in the center of a side, but can be anywhere along the length of the side of the cell unit 10. Figures 18 and 19 show beams 76 positioned near a corner, and Figure 20 shows a beam in the central part of a side. Thus, the beam 76 can be provided anywhere along the side of the cell unit 10.

[0184] Although only two beams are shown in Figure 9, it should be noted that they are preferably located at the downstream end of the cell unit with respect to the direction of fluid flow through the stacked cell unit (see Figure 10 for the direction of that flow).

[0185] Similarly, from Figures 10 to 19, it can be seen that instead of just two beams 76, in many preferred embodiments there are a total of four beams, two on each side of the cell unit 10 and at or near each end.

[0186] Fluid ports 60 are also shown in Figures 8 to 20. In the example in Figures 8 to 17, there are two fluid ports in the end region of the cell unit 10, giving the cell unit 10 a total of four fluid ports, while each end of the cell unit 10, on the end plate 62 (separated from the cell unit 10 by the current collector plate 52 and an insulating plate 50 (see Figure 6 as an example) not shown), on which the cell unit 10 is stacked, is provided with a single fluid port 60. These allow for the circulation of fuel and air / oxidizer through the stack 12.

[0187] In Figure 11, for the fuel cell, the fluid ports 60 on the end plate 62 are ports for the flow of the oxidizer, while the two pairs of fluid ports 60 at the ends of the cell unit 10 are fuel ports. However, depending on the configuration of the active electrochemical component layer of the fuel cell, these may be reversed to ensure that the fuel and oxidizer are in contact with the appropriate side of the cathode or anode of the cell unit.

[0188] Referring now to Figure 11, a further embodiment is shown. This is similar to the embodiment in Figure 10, which has four beams 76, but instead of the square recesses of the corners 74, the rounded corners from Figure 9 are used.

[0189] Figure 11 schematically shows the fuel flow and air flow (oxidizer flow) in the fuel cell operating mode. As can be seen from the figure, air or oxidizer flows into a volume defined by the housings 68 and 70 at one end of the cell unit 10 through the two fluid ports 60 of the end plate 62 (hereinafter referred to as the air flow input port 80 and the air flow output port 82). Within that volume, it rises, circulates through the cell units 10 between adjacent cell units 10, and descends before exiting through the air flow output port 82. The direction of this flow defines a central longitudinal flow line 88 from the first end of the cell unit to the far end of the cell unit 10. Lateral air passages 89 are also shown, which pass closer to the beam and near the sides of the cell unit 10. In practice, there are multiple channels through the stacked cell units 10, which may be linear or spiral depending on the design of the cell units, particularly any protrusions or recesses, bars or troughs on the separator plates of the cell units. See Figures 1 to 5 for various potential different shapes of protrusions / bars / grooves / recesses defining the channels. Other designs known in the art will also be apparent to those skilled in the art.

[0190] Depending on the direction of the air or oxidizer flow, Figure 9 shows that there are only two electrical insulation beams 76, which are preferentially located at the outlet end of the cell unit 10 (at least with respect to the air / oxidizer flow). This is because the airflow tends to push the cell unit 10 toward its outlet end, which is usually the hot end of the stack when parallel flow is used for the fuel and oxidizer, making it a preferred end for the beams 76. Therefore, by positioning the beams 76 at the far end, the contact point between the corner 74 and the beams 76 has a net angled return force at least partially toward the inlet end, and the beams resist the cell unit being pushed in that manner. Thus, the cell unit 10 can resist movement due to the airflow by the beams 76. On the other hand, the electrical insulation plates rest only on the sides and therefore do not have an angle of holding force to resist the cell unit being pushed in that manner, and over time the cell unit 10 may slide against the electrical insulation plates 78, and thus eventually lose contact with the electrical insulation plates 78 on their sides.

[0191] Referring further to Figure 11, the fuel flow in this embodiment is shown to flow in the same direction as the air / oxidant flow, but this flow instead lies between the layers of the individual cell units and therefore inside the cell unit 10. Thus, in this example, this is a parallel flow configuration. For this purpose, the pairs of fluid ports 60 at each end of the cell unit 10 are provided with a pair of fuel input ports 84 and a pair of fuel output ports 86, respectively, located toward the opposing ends of the cell unit 10, and are numbered as such in Figure 11.

[0192] As explained with respect to Figures 1 to 7, air and fuel flow through or between cell units in such a manner that they do not mix, but both can flow over appropriately opposing layers of the electrochemically active layer of the cell unit in order to bring about the desired function of the cell stack assembly. In the case of metal-supported types, the metal support plates can be perforated or porous to allow for later interaction between the fuel and the electrochemically active layer, as shown in Figures 2, 3, and 4.

[0193] From Figure 11, it can be observed that the airflow flows between opposing beams 76 at the far end of the cell unit 10, where the airflow is constricted between the two beams 76 compared to the region in front of those beams, as shown by the curved airflow line 89 in Figure 11. This constriction ensures that the airflow is more concentrated between the beams 76 compared to the wider space in front of them. This is an advantageous feature in a parallel flow configuration, as the hottest ends of the cell unit are at the fuel and air outlet ends. The constriction, and therefore the increased density of the airflow, enhances the cooling effect and thus helps control the temperature of the cell unit's outlet end. While this is particularly advantageous in a parallel flow configuration, it can also be beneficial in a counterflow configuration, as the air is heated as it crosses the cell unit 10 and therefore requires an increased density of airflow to achieve a similar level of cooling.

[0194] Next, referring to Figure 12, a nearly fully assembled cell stack is shown. In Figure 12, multiple stacked cell units 10 are shown in a configuration having electrically insulating beams at each corner 74, as in Figure 11. There are electrically insulating plates 78 extending downward from each of its two long sides. Furthermore, two halves 68, 70 of the housing 58 are fitted around the stacked cell units. In this embodiment, it can be seen that the two halves 68, 70 of the housing 58 are positioned so as to press the ends of the electrically insulating plates 78 against the beam 76 and also directly against the beam 76. This provides a net clamping force on the beam 76, with both lateral and longitudinal force components relative to the central flow line 88 (see Figure 11), pushing the beam 76 into the recessed corners 74 of the cell units 10. This bidirectional clamp provides a holding force to the stack of cell units 10, thereby keeping the individual cell units 10 in the stack fixed laterally and resisting forward longitudinal movement. Furthermore, since beams are also present at the input ends of the cell units, the cell units cannot move backward either. Thus, the cell units are clamped or held side by side and locked against individual relative movement, and therefore the likelihood of the cell units being damaged or moved by external forces applied to the stack assembly is reduced, thus maintaining the effectiveness of the seal between the layers (the seal is known in the art and is usually by an electrically insulating gasket, typically a mica gasket).

[0195] As explained with respect to Figures 1 to 7, gaskets are typically placed between cell units 10 to manifold the ports together so that a passage is formed for the fluid passing through the stack (in the examples of Figures 1 to 4 and 8 to 20, this is only fuel, but potentially also oxidizer as in Figures 5 to 7).

[0196] Therefore, in the present invention, relative turbulence between the cell units 10 is avoided, and thus the integrity of these fluid passages is maintained, as loss of integrity is highly undesirable given the possibility of ignition and potential explosion due to the mixing of fuel and oxidizer at the normal operating temperatures of these cell units.

[0197] Next, referring to Figure 13, the configuration of Figure 12 is again shown, but here four busbars 54 extending from the current collector plate 52 (not shown, see Figure 14) through four beams are also shown. These allow the collected current to be sent to the terminals of the top plate (not shown, see Figure 7 for a similar configuration with two terminals).

[0198] Next, referring to Figure 14, the configuration of Figure 12 is again shown with one portion 70 of the housing and one of the electrical insulating plates 78 removed. This shows that the current collector plate 52 is visible beneath the stacked cell units 10. Between the current collector plate and the lower end plate 62, an additional electrical insulating plate 50 can be provided to insulate the end plate 62 from the current collector plate, similar to that shown in Figure 6.

[0199] With the second part 70 of the housing removed, the oxidizer outflow port 82 of the lower end plate 62 is also visible. As shown, the current collector plate 52 does not extend over the oxidizer ports 80, 82. The electrical insulation plate is not similar, but in some examples, the electrical insulation plate 50 may be similar, in which case a corresponding port can be provided on it so that the port remains open to the internal volume of the housing at the end of the cell unit 10.

[0200] Next, referring to Figures 15, 16, and 17, various steps in the assembly process of the cell stack assembly are shown. These are preferred steps according to a sixth aspect of the present invention. Figures 14 to 16 are partial cutaways of the stack assembly of Figure 13, in which the beam 76 is cut shorter and fewer cell units 10 are stacked. This is to make the electrical insulating plate 78 behind it visible.

[0201] As shown in Figure 15, the stack of cell units 10 is stacked on the lower end plate 62 together with the first insulating plate 50, the current collector plate 52, and the four electrical insulating beams 76. The four beams 76 are positioned in the squares of the stacked cell units. To hold two beams at the rear of the stacked cell units 10 (as shown), the first electrical insulating plate 78 is fitted along the far longer side of the cell unit 10, adjacent to the rear of these two beams 76, and the first housing half 68 holds them in place.

[0202] Next, Figure 16 shows the two (illustrated) closer beams 76 and a second electrical insulating plate 78 positioned against the (illustrated) closer long edge of the cell unit 10.

[0203] Next, Figure 17 shows the rear half of the housing 70 fitted to the second electrical insulating plate 78 and the two (illustrated) closer beams 76 for clamping the assembled components together.

[0204] Finally, in this embodiment, the two halves 68, 70 of the housing 58, which is the skirt, can be joined together by welding or other means in a clamped state along a pair of weld lines 72 at each end, which are provided at the short end of the cell stack in this example.

[0205] The provision of the housing or skirt in two halves simplifies the process of assembling the cell unit 10 with the beam and electrical insulating board, clamping the assembled components together, and thus welding the skirts together while maintaining compressive forces across the beam and cell unit. These compressive forces hold the cell units in their desired relative positions and thus maintain the integrity of the fluid columns formed therein by the fluid ports and gaskets between the ports on each cell unit, as seen, for example, in Figures 3, 4, and 6.

[0206] Next, referring to Figures 18 and 19, an alternative configuration is shown, in which the beam 76 is instead separated from the corner. The housing 58 is also shown to be divided into two halves 68, 70, but here only the front half 68 is shown. To complete the assembly of this stack assembly 12, the second electrical insulating plate 78 must be fitted so as to be mirror image of the first electrical insulating plate 68 already shown, and then the back half 70 of the housing 58 is installed so as to be compressed or clamped between the beams 76 across the cell unit.

[0207] In this embodiment, the housing compresses the beam only in contact with it, rather than compressing it both directly and indirectly, and the housing 58 does not compress the beam 76 through the electrical insulating plate 78. The electrical insulating plate 78 compresses only in contact with the sides of the cell unit 10 instead. However, the beam 76 is still compressed in contact with the cell unit in multiple directions due to the shape of the recess in the cell unit 10, which in this example matches the shape of the wall opposite the beam. However, other shapes of the recess and beam, as shown in Figures 10 and 20, are also within the scope of the claimed invention, provided that square or rectangular recesses are available and different beam shapes are provided.

[0208] Referring to Figure 20, we can see that this housing is a one-piece sleeve that fits onto the component in one go. It can be bent to fit onto the component and therefore can still be held biased against the beam. It also surrounds the beam 76 and electrical insulating plate 78 on the two long sides of the cell unit 10.

[0209] Referring now to Figure 21, further embodiments of the present invention are shown. In this embodiment, which is substantially similar to the embodiments in Figures 11 to 17, the beams 76 also have busbars 54 extending through each of them, each abutting against a corner 74 of the fuel cell unit 10, where there is one beam 76 at each corner 74 of the stack of cell units 10. Furthermore, each busbar 54 connects to a current collector plate 52 located on the underside of the stack of cell units 10, extending upward from there. However, the beams are not one-piece but are each made of two parts, namely a first or lower part 92 and a second or upper part 94, with the second part 94 stacked on top of the first part 92.

[0210] In this embodiment, the two parts are in the form of the same tube or cylinder, with the busbar 54 extending through its central hole.

[0211] During assembly, the four busbars 54 can be electrically connected by welding or other means to the current collection plates 52 which are stacked on the end plates 62 of the cell stack assembly 12.

[0212] Next, with the four first parts 92 positioned on the busbar 54 to align the stack of cell units 10, the cell units 10 can begin to be stacked on the current collector plate 52. As the stack approaches the top of the first parts 92, the second parts can be placed on the busbar, and then the stack of cell units 10 is completed in the space between the four second parts 94 of the beam 76. Finally, the upper current collector plate (not shown), upper end plate (not shown), electrical insulating plate 78 (one shown), and housing 58 (one shown) can be fitted around the stack of cell units 10.

[0213] In some embodiments, more than two parts may be provided, especially for higher stacks.

[0214] Referring next to Figure 22, a further modification is shown. In this embodiment, two parts 92, 94 of the beam 76 are provided to be adjustable in length. This allows the same two parts to be used for various different stack heights. Figure 23 shows these two parts in more detail. Figure 24 shows another form of parts 92, 94 of the beam 76 to allow the length of the beam 76 to be adjusted, and those parts 92, 94 are shown in more detail in Figure 25.

[0215] In Figures 22 and 23, the length of the beam is adjustable by providing stepped or castrated ends 100 on two parts 92 and 94, the stepped or castrated ends 100 facing each other in the middle of the beam 76. These stepped or castrated ends 100 have risers and flats that can interact with the opposing risers and flats of the opposing parts, and one part can be rotated relative to the other part around an axis defined by a central hole (for example, around the busbar 54), so that different risers and flats can engage with each other, resulting in a change in the length of the stacked parts 92 and 94.

[0216] During assembly, the stacked parts 92 and 94 may initially be placed on top of each busbar 54 at a shortened length. This allows access to the top of the busbar 54 for welding or otherwise electrically connecting it to an upper electrical connector (not shown). If placed at full length instead, access to the top of the busbar may be blocked by the top of the upper current collector plate or the top of the beam 76, or both. Once the top of the busbar 54 is electrically connected to the upper electrical connector (not shown), the length of the beam 76 can be adjusted to fit under the upper current collector plate.

[0217] Referring instead to Figures 24 and 25, an alternative form of beam 76 is shown, which is also adjustable in length, but here the length can be changed more infinitely between a maximum length and a minimum length, rather than the predefined stepped changes provided by the risers and flat sections. For this purpose, the opposing ends 100 of the two parts 92, 94 each have a chamfered or angled / inclined surface 100 and a stop member 102. The length of the beam 76 can also be changed by rotating the two parts 92, 94 relative to each other around their central axis (i.e., around the busbar 54), and the same advantages as above are obtained. The stop members 102 of each end 100 interact with each other at the endpoints of the length change, so the stop members provide a predetermined limit to the length change.

[0218] In each of these two variations, in which the beam length is adjustable, the length can be locked after installation, for example, by using thermal paste or adhesive or by providing keying features.

[0219] Referring now to Figure 26, an alternative method is provided for providing access to the underside of the upper current collector plate, for example, to allow the ends of the busbar 54 to be easily connected by the upper electrical connector. In this embodiment, the upper part 94 is a slotted component, which is substantially tubular as already described, but has a slot 104 extending from its central hole to its side wall, the slot 104 being wide enough to be installed on the busbar 54 without accessing the free end of the busbar 54. This configuration allows the first parts (and here a separate intermediate part 96) to be initially installed on the busbar 54, the cell units 10 to be stacked between them, and further stacked up to the top of the stack, then the upper current collector plate (and upper electrical connector) to be installed, and then the upper part 94 of the beam 76 to be fitted, which is made possible by fitting them onto the busbar 54 using the slot 104. The upper part 94 can then be rotated so that the slot 104 is oriented away from the corner 74 of the cell unit 10, so that they do not come loose.

[0220] In this embodiment, the first part 92 is also shown to be a slotted part because it may be desirable to remove it (or later install it on the intermediate part 96) to access, for example, the busbar 54 to connect to the lower current collection plate 52 (or for maintenance).

[0221] In some embodiments, the configuration of this slotted part may also feature the stepped or chamfered surfaces of the previous embodiments.

[0222] Referring now to Figure 27, further alternative configurations of the beam 76 are shown. In this embodiment, the beam is shown as a one-piece beam, although they may be made of more than one piece as previously described. However, in this embodiment, the top of the beam has a semicircular notch 98 at the top, as shown in the figure. This semicircle abuts the corner 74 of the cell unit 10 at the top of the stack, but its flat surface faces outward, providing a flow path around the outside of the beam 76 at the top of the stack. Such a flow provides an additional route for air to flow into the top of the stack (to flow between the cell units), as well as through the gaps between the beams at each end of the stack. This increased airflow can improve thermal management at the top of the stack, which is generally a hotter location in the stack than the bottom or middle of the stack.

[0223] In this embodiment, for structural symmetry (and therefore to reduce the manufacturing cost of the component), the first part 92 of the beam is also provided with a notch 98. However, if such further flow is not required there, the lower part 92 does not need to have a notch 98.

[0224] In this embodiment, the intermediate section 96 is shown as a complete tubular shape without notches, but notches may be provided as needed to further cool the intermediate area of ​​the stack.

[0225] Instead of a semicircular notch, other forms of notches would also provide similar additional channels. For example, a beam part with notch 98 could be a coaxial tube structure in which a portion of the outer tube is cut out. Such a structure allows the busbar 54 to remain insulated around its periphery even in the notched region, which helps prevent airborne contaminants (or dust) from easily accessing the busbar.

[0226] In these alternative embodiments, the beam still has a straight end face facing the corners 74 of the cell units 10, so that the beam still functions as an alignment guide for stacking the cell units 10. This straight end face, which may be rounded as part (segment) of the tube, rotates to engage with the corners 74 of the cell units 10.

[0227] The beam parts 92, 94, and 96 are preferably formed from mica tubes. However, the stepped end 100, the chamfered end 100 and stop 102, and the slot 104 form smaller details on the beam, reducing the structural integrity of its shape. Therefore, it may be preferable to instead fabricate one or more of the beam parts 92, 94, and 96 from a ceramic material with more suitable structural strength.

[0228] As will be apparent to those skilled in the art, various structural shapes of the cell unit have been described herein, ranging from the generally elliptical shapes in Figures 1 to 4 to the generally rectangular shapes in Figures 5 to 20. However, the present invention can also utilize many other shapes of the cell unit and is applicable to many chemical types of electrochemical cells. In fact, those skilled in the art will understand that the shape of the cell unit can be broadly modified while still using the electrically insulating beam 76 of the present invention. Thus, the present invention has been described above merely as an example, and modifications to the invention in detail can be made within the scope of the claims appended herein.

Claims

1. An electrochemical cell stack, wherein the cell stack is Each of the stacked cell units defines the outer perimeter, A housing surrounding the stack so as to define or enclose a volume around the outer periphery, Displaced between the housing and the plurality of stacked cell units, and each contacting one of the two opposing sides of the plurality of stacked cell units, two opposing electrical insulating plates, An electrically insulating beam extending across multiple cell units of the stack and engaging with the outer periphery of those multiple cell units, Equipped with, The electrical insulating beam also engages with the housing and one or both of the electrical insulating plates. The electrically insulating beam generally extends in the stacking direction of the stacked cell units, The aforementioned electrical insulating beam is a cell stack positioned between the outer circumference of the cell unit and the housing.

2. The cell stack comprises at least two electrically insulating beams, each extending across the plurality of cell units and engaging with the outer periphery of at least two of the plurality of cell units. The beam defines a line extending between the two beams, and the line defines a transverse line spanning each cell unit. Therefore, a) The contact tangents between each beam and each of the cell units cooperate to resist the movement of each of the cell units in both lateral directions along the defined transverse line of the cell unit and in at least one longitudinal direction that is generally perpendicular to the transverse line and generally plane with respect to the outer circumference of each cell unit, or b) The contact tangents between each beam and each of the cell units cooperate in each beam to resist the movement of each of the cell units in both at least one transverse direction along the defined transverse line of the cell unit and at least one longitudinal direction that is generally perpendicular to the transverse line and generally plane with respect to the outer perimeter. The cell stack according to claim 1, which is either or both of the above.

3. The cell stack according to claim 1, wherein an electrical insulating plate or each electrical insulating plate that engages with the edge of the cell unit has a cell engagement surface that provides engagement, and the beam closest to one of the cell engagement surfaces of the electrical insulating plates has a cell engagement surface that extends distal to the cell engagement surface of the electrical insulating plate.

4. The cell stack according to claim 3, wherein there are two beams, each having a cell engagement surface extending distal to the cell engagement surface of the nearest electrical insulating plate, and the two beams result in a narrowing of the width of the cell unit between the two beams compared to the width between the two electrical insulating plates.

5. Each electrical insulating plate also engages with the inner wall of the housing, the cell stack according to claim 1.

6. The cell stack according to claim 1, wherein two or more electrical insulating plates are provided between each opposing side of the plurality of stacked cell units and the housing.

7. The cell stack according to claim 1, wherein the electrical insulating plates are arranged on only two of the sides of the stacked cell units.

8. The cell stack according to claim 1, wherein more than one electrical insulating plate is arranged side by side or stacked in a common plane relative to two opposing sides of the stacked cell unit.

9. The cell stack according to claim 1, wherein the beam or each beam is formed of two or more parts.

10. The cell stack according to claim 1, wherein the length of the beam or each beam is adjustable.

11. The cell stack according to claim 1, wherein the beam or each beam has one or more notched areas to increase fluid flow in that region.

12. The housing initially comprises at least two separate parts, The at least one electrically insulating beam is assembled between one of the housing's initial separate parts and the stacked cell units, the electrically insulating beam extends across the plurality of cell units and contacts the outer periphery of at least two of the plurality of cell units, exerting a force that resists the plurality of cell units moving further toward the beam. The cell stack according to claim 1, wherein the first and second initial separate parts of the housing clamp or engage at least one beam with respect to the outer circumference of at least two of the plurality of cell units when the two parts of the housing are closed together.

13. The cell stack according to claim 12, wherein at least two parts of the housing are welded together in a clamped state to maintain a clamping force.

14. The cell stack according to claim 1, wherein the at least one beam defines a barrier to the flow of fluid entering and leaving the stacked cell unit, blocking or reducing the flow of fluid around the outside of the beam between the outer periphery of the cell unit and the housing, and directing the fluid flow through or toward a central stream passing through the stacked cell unit.

15. The cell stack according to claim 1, wherein the at least one beam defines a barrier to the fluid flow entering and leaving the stacked cell unit, thereby concentrating the airflow through the central stream passing through the stacked cell unit and reducing the airflow to the side of the central stream adjacent to the side of the cell unit.

16. The cell stack according to claim 1, wherein the at least one beam is seated in a recess or depression formed on the outer circumference of the cell unit.

17. The cell stack according to claim 16, wherein the recess or recess wraps around the beam over at least a 90-degree segment.

18. The cell stack according to claim 1, wherein the housing comprises a skirt around the cell unit, and the skirt is formed of at least two parts joined together at their seams.

19. A method for assembling a cell stack according to claim 1, wherein the method is: A stacked cell unit, where each cell unit defines the outer perimeter, At least two electrically insulating beams, each extending across multiple stacked cell units and assembled relative to the stacked cell units so as to engage with the outer periphery of those multiple cell units, This includes providing The aforementioned method, The method involves fitting a housing around the stacked cell units and the electrically insulating beam, wherein the housing defines a volume around the outer circumference, and the housing is initially divided into at least two separate parts. Includes, The first and second initial separate parts of the housing, when the two parts of the housing are closed together, clamp against the outer periphery of at least two of the plurality of cell units, exerting a force that resists further movement of the plurality of cell units toward the beam, and the initial separate parts are then connected or joined to each other in a clamped state to maintain the clamping force by the beam toward the outer periphery of at least two of the plurality of cell units, in a method.

20. There are at least two electrically isolated beams, One electrically insulating beam is assembled between the first initial part of the housing and the stacked cell units, and a second electrically insulating beam is assembled between the second initial part of the housing and the stacked cell units, and each of the at least two electrically insulating beams extends across a plurality of cell units and contacts the outer periphery of at least two of the plurality of cell units, exerting a force that resists the plurality of cell units moving further toward the beam. The first and second initial separate parts of the housing, when the two parts of the housing are closed together, clamp against the outer periphery of at least two of the plurality of cell units, exerting a force that resists further movement of the plurality of cell units toward the beam, and the initial separate parts are then connected or joined to each other in a clamped state to maintain the clamping force by the beam toward the outer periphery of at least two of the plurality of cell units, according to claim 19.

21. The method according to claim 19 or 20, wherein the first and second initial parts of the housing are separate parts and are indirectly clamped to the outer periphery of at least two of the plurality of cell units via one or more electrical insulating plates in addition to the electrical insulating beams or each of the electrical insulating beams.

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