Components and methods for redox flow batteries

Abstract

Components for use in and methods for battery systems, and particularly redox flow battery systems, are disclosed. In aspects the invention relates to an isolator plate, a coupling, a cell stack, a fluid-carrying component, a structural end plate for a cell stack, and a redox flow battery. The components and methods provide for improved reliability, ease of manufacture and maintenance, and cost-efficiencies.

Description

[0001] Components and Methods for Redox Flow Batteries FIELD OF THE INVENTION

[0002] The present invention relates to apparatus for use in battery systems, and particularly redox flow battery systems. In various aspects the invention relates to an isolator plate, a coupling, a cell stack, a fluid-carrying component, and a structural end plate for a cell stack.

[0003] BACKGROUND OF THE INVENTION

[0004] Redox flow battery systems typically comprise multiple cells connected to one another in a bipolar electrochemical cell arrangement, electrically in series, to increase output voltage. These are usually placed in physical proximity next to one another in an arrangement referred to as a stack, or cell stack. Each cell stack is associated with at least one tank, typically at least one tank pair comprising two tanks for anolyte and catholyte, together with one or more pumps that circulate electrolyte from the tank(s), through the cell stack and back to the tank(s). These are referred to as a battery module. Sometimes more than one cell stack can share a tank.

[0005] Flow battery systems are complex having mechanical, chemical and electrical constraints and requirements. Large scale adoption of flow battery systems may be impeded where reliability is in question and / or the cost is too high for any of the component elements, and / or the cost of the footprint is too high.

[0006] The mechanical and fluidic systems of redox flow batteries face certain challenges. For example, fluid connections between electrolyte tanks and cell stacks need to be made during assembly of a redox flow battery system. Such fluid connections may need to be made and unmade repeatedly during assembly, and again during maintenance and / or repair.

[0007] The present invention seeks to address one or more challenges associated with the prior art.SUMMARY OF THE INVENTION

[0008] In accordance with a first aspect, there is provided an isolator plate for assembly between a structural end plate and a stack component in a cell stack for a redox flow battery, the isolator plate comprising:

[0009] a planar region for isolating, in use, the structural end plate from the stack component; and

[0010] a spigot extending away from a plane of the planar region, the spigot for extending, in use, through an aperture in the structural end plate, the spigot defining a fluid conduit extending through the planar region.

[0011] At least a surface of the spigot may be formed from a weldable polymer. For example, at least a surface of the spigot may be formed from a weldable polymer, wherein the surface of the spigot formed from a weldable polymer is complimentary (e.g. in shape) to a corresponding surface of a coupling (e.g., a coupling of the second aspect below) formed from a weldable polymer, e.g., such that the spigot and the coupling may be permanently attached to each other (e.g., by welding).

[0012] Any one or any combination of an outer surface, an end surface, and an inner surface of the spigot may be formed from a weldable polymer. An end region of the spigot may have a surface which is formed from a weldable polymer. This may allow the spigot to be welded to a compatible coupling.

[0013] Welding, such as fusion welding, is a relatively cheap and reliable method for permanently joining compatible components in a leak-free manner.

[0014] An isolator plate with such a spigot may allow for efficient assembly of a cell stack module, and / or allow for efficient connection of a coupling, such as a quick-connect coupling, to the cell stack module.

[0015] In this document, the term “spigot” refers to a hollow conduit, such as a tube. In general, although not universally, a “spigot” is a relatively rigid component that is not intended to flex in a substantial manner (in comparison to a flexible hose, for example). In general, although not universally, a “spigot” may be intended to pass through, and / or extend from, a wall, housing, or other structure, to allow for the passage of fluid from one side of the wall, housing, or other structure to the other side. Although not essential, an outer surface of thespigot may include a portion that tapers in a direction away from the planar region. Where a coupling is being welded (e.g., fusion-welded) to the spigot, the taper may allow contact to be made between the surfaces being welded without the need to slide the melted surfaces along each other, as would be the case with a cylindrical surface. The taper may also assist with centring of the spigot within a coupling to which it is being connected.

[0016] The spigot may extend normally from the planar region. The spigot may be integral to the isolator plate. The spigot may be unitary to the isolator plate. The spigot may be manufactured in the same process as when manufacturing the isolator plate, and the spigot may be manufactured from the same material as the isolator plate. For example, the spigot and isolator plate may be moulded as a single unit.

[0017] At least an outer surface of an end region of the spigot may be formed from a weldable polymer, the end region of the spigot being distal to the planar region. This may allow the spigot to be welded to a compatible coupling. Welding, such as fusion welding, is a relatively cheap and reliable method for permanently joining compatible components in a leak-free manner.

[0018] At least an outer surface of the spigot that, in use, extends beyond the aperture on a side of the structural end plate opposite the side on which the planar region of the isolator plate is disposed may be formed from a weldable polymer.

[0019] At least an inner surface of the spigot, and / or an end surface of the spigot, may also or alternatively be formed from a weldable polymer. This may allow the spigot to be welded to a compatible coupling.

[0020] The isolator plate (e.g., including the spigot) may be moulded from a polymer. The spigot may also be moulded from a polymer. Optionally, the polymer may be a weldable polymer, such as a fusion-weldable polymer. The spigot may have surfaces which are formed from a weldable polymer.

[0021] The polymer may be polypropylene. Polypropylene may provide a suitable combination of weldability, flexibility, electrical isolation resistance, and corrosion-resistance. However, the polymer may also be, for example, polyethylene or polyvinylidene fluoride.The isolator plate may comprises at least two spigots, preferably from two to four spigots, more preferably four spigots. The spigots may be provided in pairs. For example, a first pair of the spigots may be provided adjacent to one edge of the structural end plate and a second pair of the spigots may be provided adjacent to an opposite edge of the structural end plate.

[0022] In accordance with a second aspect, there is provided a coupling configured for permanent attachment to the spigot of an isolator plate according to the first aspect, the coupling defining an internal conduit and comprising:

[0023] a first end configured for attachment to the spigot; and a second end configured to allow releasable connection of a complementary fluid connector.

[0024] Preferably, at least a surface of the first end (e.g., of a body intended for connection to the spigot to be welded) is formed from a weldable polymer. For example, at least a surface of the first end may be formed from a weldable polymer, wherein the surface of the first end formed from a weldable polymer is complimentary (e.g., in shape) to a corresponding surface of a spigot (e.g., of the first aspect above) formed from a weldable polymer, e.g., such that the spigot and the coupling may be permanently attached to each other (e.g., by welding).

[0025] The surface of the first end (e.g., the body intended for connection to the spigot to be welded) formed from a weldable polymer may be any one or any combination of an inner surface, an outer surface, and an end surface of the first end.

[0026] When the coupling is attached to the spigot, at least a portion of the internal conduit may be in fluid communication with the fluid conduit through the spigot.

[0027] The coupling may be, for example, a quick-connect coupling. A quick-connect coupling offers the ability to make a quick, reliable fluid connection, which may be useful during assembly and / or maintenance of a flow battery when connections may need to be repeatedly made and remade.

[0028] In this document, the term “quick-connect coupling” (and related terms) refers to a coupling that allows for a detachable fluid connection to be formedbetween two components. For example, one component may be a fluid conduit, such as a flexible hose, and the other component may be a housing comprising an internal fluid path and / or an internal fluid reservoir to which the flexible conduit is to be connected. In other examples, both components may be fluid conduits, such as flexible hoses. In yet other examples, both components may be housings comprising an internal fluid path and / or an internal fluid reservoir.

[0029] A quick-connect coupling is typically configured to be connected to a complementary quick-connect coupling. Preferably, the quick-connect coupling is configured to be connected to a complementary quick-connect coupling: by pushing the couplings together, without unfastening a fastening, and / or without a tool. Preferably, the quick-connect coupling is configured to be disconnected from a complementary quick-connect coupling: in a single movement, by unfastening a single fastening, and / or without a tool. For example, it is common to provide a complementary pair comprising so-called “male” and “female” quick-connect couplings. The female quick-connect coupling comprises a recess into which a complementary portion of the male quick-connect coupling is inserted to make the connection.

[0030] A quick-connect coupling is typically configured such that, when first connected to a complementary quick-connect coupling, the two couplings are locked (often automatically) together until released by a release mechanism. For example, a clip, latch, catch, or other mechanism, may automatically lock the two couplings together once they are connected. The clip, latch, catch, or other mechanism, must then be released to allow disconnection of the two couplings. Other locking mechanisms may be used.

[0031] Some quick-connect couplings include an internal stop or valve that automatically closes when the quick-connect couplings are not connected. Connecting the quick-connect couplings opens the stop or valve, allowing movement of fluid through the quick-connect couplings.

[0032] Some quick-connect couplings are manually operable. That is, it is not ordinarily necessary to use a tool to connect and / or disconnect the quick-connect couplings. For example, quick-connect couplings may be connected by pushing one into the other, resulting in automatic locking of the quick-connect couplingstogether. In other examples, a clip, latch, catch, or other mechanism may need to be manually operated to allow connection of the quick-connect couplings. In yet other examples, a click, latch, catch or other mechanism may need to be manually operated to allow disconnection of the quick-connect couplings. In yet other examples, a tool may be required to lock, unlock, connect and / or disconnect quickconnect couplings. The tool may be as simple as, for example, a flat-bladed screwdriver.

[0033] The coupling may be a female quick-connect coupling.

[0034] In general, on a male quick-connect coupling, the outer surface of the portion of the male quick-connect coupling that engages an O-ring within a corresponding female quick-connect coupling is relatively exposed when compared with the corresponding inner surface of the female quick-connect coupling. As such, it is more likely that the outer surface of the male quickconnect coupling will be damaged during installation and / or maintenance involving the connection and disconnection of the quick-connect couplings to and from each other.

[0035] Where the quick-connect coupling is relatively easy to replace, the risk of damage may be of lower concern. However, if the quick-connect coupling is to be attached (and particularly permanently attached) to a difficult and / or expensive-to-replace component, it is preferable to use a female quick-connect coupling, the sealing surface of which is less likely to be damaged than a corresponding male quick-connect coupling.

[0036] A portion of the body, intended for connection to the spigot, may define a radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached. This may provide a good contact area between the portion of the body and spigot, which may be desirable when the body is to be welded or bonded to the spigot.

[0037] Alternatively, a portion of the body, intended for connection to the spigot, may define a radially-outer surface that has a profile complementary to that of an inner surface of the spigot to which the coupling is to be attached. This may provide a good contact area between the portion of the body and spigot, which may be desirable when the body is to be welded or bonded to the spigot.The radially-inner surface of the coupling may be circular in crosssection. In other implementations, other cross-sectional shapes may be employed.

[0038] The inner surface may diverge in cross section in a direction towards an axially outer end of the first end. The divergence may be selected to match or complement a taper of a spigot to which the coupling is to be connected, for example by welding (such as by fusion welding) or bonding. This may provide a good contact area between the portion of the body and spigot, which may be desirable when the body is to be welded or bonded to the spigot.

[0039] The radially-inner surface may comprise a weldable polymer, such as a fusion-weldable polymer. The body may be moulded from a weldable polymer, such as a fusion-weldable polymer.

[0040] The polymer may be polypropylene. Polypropylene may provide a suitable combination of weldability, flexibility, and corrosion-resistance.

[0041] The internal conduit may extend along a longitudinal axis within the body, and the coupling may comprise:

[0042] a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to a structural end plate; and

[0043] a circumferentially-extending radially-inner wall connected to the outer wall at a position distal to the first end, the inner wall extending towards the first end and defining the radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached;

[0044] wherein the outer wall and the inner wall may define an annular space between them, the annular space being open adjacent to the first end.

[0045] The annular region defined by the gap between the inner wall and the outer wall is may be V- or U-shaped in radial section.

[0046] The mounting component may comprises at least one flange, the or each flange being configured for fastening to the structural end plate by way of a fastener. The or each flange may include at least one aperture for receiving such a fastener.

[0047] The body may be configured such that the inner wall and the outer wall can move relative to each other, particularly in the radial direction. This maybe achieved by the body being configured to allow bending or flexing around a region where the inner wall and the outer wall join each other. Alternatively, or in addition, either or both of the inner and outer walls can themselves bend or flex. The compliance between the inner and outer wall offered by this relative movement may reduce the transmission of forces from the coupling to a spigot to which it is permanently connected. Such forces include those placed directly on the coupling as well as those placed on an attached complementary fluid coupling.

[0048] The coupling may comprise a ridge extending circumferentially around a radially-inner surface of the body, the ridge being configured to inhibit axial movement of molten polymer from a welding region during welding of the coupling to the spigot.

[0049] The body may comprise a radially-inner O-ring sealing surface for sealing engagement with at least one O-ring.

[0050] The O-ring sealing surface may be axially dimensioned to accept two axially-adjacent O-rings. Optionally, the O-ring sealing surface is axially dimensioned to accept two axially-adjacent O-rings separated by an O-ring spacer. Multiple O-rings may improve sealing. During insertion of a coupling past the O-rings, an O-ring initially contacted by the coupling may “wipe” contaminants such as liquid or crystallised electrolyte from the coupling, which may improve the seal between the coupling and one or more other O-rings.

[0051] The body may comprise a retention feature for retaining a sealretainer that, in use, retains the at least one O-ring in its installed position.

[0052] The retention feature may comprise at least one radially-extending opening for receiving a radially-extending tooth or pawl of the seal-retainer.

[0053] Optionally, the at least one radially-extending opening may be a through opening that extends to an outer surface of the body, the through opening being positioned such that, when the coupling is installed onto the spigot at a predetermined orientation, any fluid escaping, in use, past the at least one O-ring can drain through the opening.

[0054] The coupling may comprise the seal-retainer, the seal-retainer being annular and defining:a seal-side axial surface for engaging an axially-adjacent one of the at least one O-rings; and

[0055] at least one radially-extending tooth or pawl for engaging the retention feature when the seal-retainer is installed within the body.

[0056] The body may comprise at least one keyway configured to guide a corresponding one of the at least one radially-extending tooth or pawl as the sealretainer is axially inserted into the body. The keyway may, for example, extend axially from an axially outer end of the second end. The seal-retainer may be configured for insertion into the second end of the body.

[0057] The use of at least one keyway may help ensure that the sealretainer is inserted into the body at a suitable orientation. The at least one keyway may also provide access to at least a portion of the seal-retainer in order to enable release of the seal-retainer from the body.

[0058] The seal-retainer may comprise a radially-outwardly facing shelf extending circumferentially along at least a region adjacent to the tooth or pawl, the coupling and seal-retainer being configured such that the seal-retainer can be demounted from the coupling by using a tool to engage the shelf so as to radially deform the seal -retainer, thereby to disengage the tooth or pawl from the retention feature.

[0059] The seal-retainer may be configured to, while a male coupling (preferably, a male quick-connect coupling) is connected to the coupling and in the event of failure of a mechanism on the seal-retainer for preventing axial displacement of the seal-retainer in the direction away from the first end, axially engage a feature on the male coupling to prevent further axial movement of the seal-retainer in the direction away from the first end.

[0060] The coupling may comprise at least one O-ring installed within the body, wherein seal-retainer is retained within the body by the retention feature so as to retain the at least on O-ring in its installed position.

[0061] The male coupling may be a quick-connect coupling.

[0062] The coupling may comprise:

[0063] a first locating feature for engaging a distal end of a male coupling coupled within the coupling; anda second locating feature for engaging a portion of the male coupling coupled within the coupling, the second locating feature at a position axially spaced from the first locating feature;

[0064] the first locating feature and the second locating feature being configured to inhibit radial movement between a coupled male coupling and the at least one O-ring.

[0065] Inhibiting radial movement in this manner may reduce movement relative to, and / or the forces placed on, one or more O-rings within the coupling, which may in turn reduce O-ring wear and / or reduce the chance of leakage past the O-ring(s).

[0066] In accordance with a third aspect, there is provided a kit for assembling a redox flow battery cell stack, the kit comprising at least one isolator plate in accordance with the first aspect and at least one coupling (preferably, two, three, or four couplings) in accordance with the second aspect.

[0067] In accordance with a fourth aspect, there is provided a cell stack for a redox flow battery, the cell stack comprising:

[0068] a structural end plate;

[0069] an isolator plate in accordance with any aspect described herein, assembled with the structural end plate such that the spigot extends through an aperture in the structural end plate; and

[0070] a coupling in accordance with any aspect described herein, connected to the spigot.

[0071] The coupling may be permanently connected to the spigot by way of welding. The welding may be fusion welding.

[0072] Herein, fusion welding is preferably: socket fusion welding (also known as heated tool sleeve welding), butt fusion welding, or electrofusion welding.

[0073] The structural end plate may be permanently located (or sandwiched) between the isolator plate and the coupling.

[0074] The internal through conduit may extend along a longitudinal axis within the body, the coupling comprising:a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to the structural end plate; and

[0075] a circumferentially-extending radially-inner wall connected to the outer wall at a position distal to the first end, the inner wall extending towards the first end and defining the internal conduit adjacent to the first end;

[0076] wherein the outer wall and the inner wall define an annular space between them, the annular space being open adjacent to the first end; and wherein the at least one radially-extending mounting component is fastened to the structural end plate by way of one or more fasteners.

[0077] The mounting component may comprise at least one flange, the or each flange including at least one aperture, the at least one radially-extending mounting component being fastened to the structural end plate by way of one or more fasteners extending through the one or more apertures.

[0078] In accordance with a fifth aspect, there is provided a cell stack for a redox flow battery, the cell stack comprising a female quick-connect coupling extending from or through a structural end plate of the cell stack, the quickconnect coupling being configured to allow connection and disconnection of a corresponding male coupling attached to a fluid conduit.

[0079] The quick-connect coupling may be in accordance with the second aspect.

[0080] In accordance with a sixth aspect, there is provided an electrolytecarrying component for use in a redox flow battery, the electrolyte-carrying component being configured for connection to a flexible electrolyte conduit, the electrolyte-carrying component comprising:

[0081] a housing comprising an internal electrolyte path and / or an internal electrolyte reservoir; and

[0082] an electrolyte connector in fluid communication with the internal electrolyte path and / or the internal electrolyte reservoir, the electrolyte connector extending outside the housing;

[0083] wherein the electrolyte connector comprises a female quickconnect coupling for receiving a complementary male quick-connect coupling.The female quick-connect coupling may be permanently attached to, or integral with, the housing.

[0084] As explained above, damage to the sealing surface of a quickconnect coupling may be difficult or impossible to repair, so improved damage resistance is of particular interest if a quick-connect coupling is to be attached permanently to, or is integral with, a cell stack module.

[0085] The use of a female quick-connect coupling on an electrolytecarrying component for use in a redox flow battery (such as a cell stack module or a shunt manifold) is novel and provides benefits that are of particular interest to this specific field of application. In unrelated fields, when a quick-connect coupling is used to join, say, a flexible hose to a fixed component such as a housing, a male quick-connect coupling is mounted to the housing and a female quick-connect coupling is connected to the hose.

[0086] The housing may comprise a cell stack component or a shunt manifold component for a redox flow battery.

[0087] The female quick-connect coupling may be connected to the fluidcarrying component by way of a connection to a spigot extending from the housing.

[0088] The connection between the female quick-connect coupling and the spigot may comprise a releasable connection. For example, the connection may be a threaded or clamped connection.

[0089] The connection between the female quick-connect coupling and the spigot may comprise a permanent connection. For example, the connection may be a welded or bonded connection. For example, the connection may comprise fusion welding between a body of the female quick-connect coupling and an external surface of the spigot.

[0090] The female quick-connect coupling may be a quick-connect coupling in accordance with the second aspect.

[0091] In accordance with a seventh aspect, there is provided a structural end plate for a cell stack for use in a redox flow battery, the structural end plate comprising:

[0092] a planar region defining:a first edge; and

[0093] a second edge;

[0094] at least one reinforcing structure extending across a surface of the planar region between the first edge and the second edge, the reinforcing structure comprising a beam extending away from an outer surface of the planar region on an outer side of the planar region when the end plate is installed on a cell stack;

[0095] a first landing surface for accepting, in use, a force from a fastener, the force being in a direction to cause compression of the cell stack, the first landing surface being disposed at a first end of the reinforcing structure adjacent to the first edge; and

[0096] a second landing surface for accepting, in use, a force from a further fastener, the force being in a direction to cause compression of the cell stack, the second landing surface being disposed at a second end of the reinforcing structure adjacent to the second edge;

[0097] wherein the first landing surface and the second landing surface are positioned closer to a first plane than to a second plane, the first plane being defined by the outer surface of the planar region and the second plane being parallel to the first plane and passing through a region of the beam that is furthest from the first plane.

[0098] The beam may comprise a further region between the first edge and the second edge, wherein, in the central region and in cross-section, a first dimension of the beam measured in a direction normal to the first plane is greater than a second dimension of the beam measured across a width of the beam.

[0099] The beam may comprise:

[0100] a first transition region adjacent to the first end of the reinforcing structure; and

[0101] a second transition region adjacent to the second end of the reinforcing structure;

[0102] wherein, within the first transition region and the second transition region, a dimension of the beam measured in a direction normal to the first plane diminishes with distance from a mid-point of the beam, the mid-point of the beam being between the first edge and second edge.Within the first transition region, and in plan view looking into the plane of the structural end plate, the beam may bifurcate into a first bifurcated structure; and within the second transition region, and in plan view looking into the plane of the structural end plate, the beam may bifurcate into a second bifurcated structure.

[0103] In plan view looking into the plane of the structural end plate, the first bifurcated structure may surround the first landing surface; and, in plan view looking into the plane of the structural end plate, the second bifurcated structure may surround the second landing surface.

[0104] In plan view looking into the plane of the structural end plate, the beam may take the visual form of a double-ended open spanner.

[0105] The first landing surface and the second landing surface may each comprise at least one aperture for receiving a fastener.

[0106] A first ratio of a distance between the first landing surface and the first plane; to a distance between the first landing surface and the second plane; may be less than 0.2. A second ratio of a distance between the second landing surface and the first plane; to a distance between the second landing surface and the second plane; may be less than 0.2.

[0107] The first landing surface and the second landing surface may both be within 5 mm of the first plane. Optionally, the first landing surface and the second landing surface may both be located on the first plane.

[0108] The structural end plate may comprise a plurality of the reinforcing structures.

[0109] Optionally, the reinforcing structures extend parallel to each other. In accordance with an eighth aspect, there is provided a structural end plate for a cell stack for use in a redox flow battery, the structural end plate comprising:

[0110] a planar region; and

[0111] at least one eyelet or hook for allowing, in use, lifting of the cell stack to which the structural end plate is installed.

[0112] The at least one eyelet or hook may define an aperture, the aperture extending parallel to a plane defined by the planar region.The aperture may extend within the plane defined by the planar region.

[0113] The structural end plate may comprise at least two of the eyelets or hooks, the at least two eyelets or hooks being disposed along a, in use, top edge of the structural end plate.

[0114] The structural end plate of the eighth aspect may comprising the features of the structural end plate of any other aspect.

[0115] In accordance with a ninth aspect of the invention, there is provided a method of manufacturing the isolator plate and / or the coupling of any other aspect(s) herein. Preferably, the isolator plate and / or the coupling is / are moulded or cast.

[0116] In accordance with a tenth aspect of the invention, there is provided a method of attaching or connecting (e.g. permanently attaching or permanently connecting) a coupling of any aspect herein to the spigot of an isolator plate of any aspect herein. Preferably, the coupling may be permanently attached / connected to the spigot by way of welding. Preferably, the welding may be fusion welding. Preferably, before attaching or connecting, the spigot of the isolator plate is inserted through an aperture in a structural end plate (such as a structural end plate of any aspect herein). In accordance with an eleventh aspect of the invention, there is provided a method of manufacturing the structural end plate of any other aspect(s) herein. Preferably, the structural end plate is moulded or cast.

[0117] In accordance with a twelfth aspect of the invention, there is provided a redox flow battery (preferably, a vanadium redox flow battery) comprising any one or (where the context allows) any combination of two or more of an isolator plate of the first aspect, a coupling of the second aspect, a kit of the third aspect, a cell stack of the fourth or fifth aspects, an electrolyte-carrying component of the sixth aspect, and / or a structural end plate of the seventh of eight aspects.

[0118] BRIEF DESCRIPTION OF THE DRAWINGSAspects and implementations will now be described, without limitation and by way of example only, with reference to the accompanying drawings, in which:

[0119] Figure l is a schematic view of a redox flow battery according to an embodiment;

[0120] Figure 2 is a schematics side view of a cell stack of the flow battery of Figure 1;

[0121] Figure 3 is a schematic side view of first and second manifolds of the flow battery of Figure 1, showing anolyte and catholyte connections and flow;

[0122] Figure 4 is a schematic vertical section through a cell stack of the flow battery of Figure 1;

[0123] Figure 5 is a perspective view of a cell stack of the flow battery of Figure 1;

[0124] Figure 6 is a rear perspective view of an isolator plate forming part of the cell stack of the flow battery of Figure 1, according to an embodiment;

[0125] Figure 7 is a front perspective view of the isolator plate of Figure 6; Figure 8 is a detail view of spigots forming part of the isolator plate of Figures 6 and 7;

[0126] Figure 9 is a rear perspective view showing the isolator plate of Figures 6 to 8 installed through a structural end plate;

[0127] Figure 10 to 12 show various perspective views of a quick-connect coupling, according to an embodiment;

[0128] Figure 13 shows the quick-connect coupling of Figures 10 to 12, installed onto a structural end plate forming part of the cell stack of Figures 2 to 5;

[0129] Figure 14 is a vertical section through the quick-connect coupling and structural end plate of Figure 13;

[0130] Figure 15 is an angled vertical section through the quick-connect coupling and structural end plate of Figures 13 and 14, with a male quick-connect coupling installed in the quick-connect coupling;

[0131] Figure 16 is a perspective view of part of a seal-retainer for use with the quick-connect coupling of Figures 10 to 15;Figure 17 is a schematic side view of a cell stack, in accordance with an embodiment;

[0132] Figure 18 is a schematics side view of a fluid-carrying component, in accordance with an embodiment;

[0133] Figure 19 is a perspective view of a structural end plate, in accordance with embodiments;

[0134] Figure 20 is a plan view of the structural end plate of Figure 19; Figure 21 is a longitudinal section through part of the structural end plate of Figures 19 and 20, along a beam;

[0135] Figure 22 is a cross section through part of the structural end plate of Figures 19 and 20, laterally through a beam; and

[0136] Figure 23 is a close-up a portion of the structural end plate of Figures 19 to 22.

[0137] DETAILED DESCRIPTION OF THE INVENTION

[0138] The invention will now be described in more detail, without limitation, with reference to the accompanying Figures.

[0139] In this document, the use of terms ‘first’, ‘second’, ‘third elements’ or ‘primary’, ‘second’ or ‘tertiary elements’ etc. (e.g. a ‘second element’) does not, where only one is mentioned, require the presence of a ‘first’ such element, unless the context requires otherwise. So, for example a ‘second element’ ‘secondary element’ does not require the presence of a ‘first element’ or ‘primary element’, although such a ‘first element’ or ‘primary element’ may be present.

[0140] Further it will be understood that ‘first’ and ‘second’ or ‘primary’ and ‘secondary’ elements, where mentioned, may refer to alternatives, typically of an equivalent or similar nature.

[0141] Various aspects and examples of an end plate for a cell stack module, and of a coupling (preferably, a quick-connect coupling), will be described. For convenience, the aspects and examples will be described in the context of a cell stack module for incorporation into a redox flow battery. It will be appreciated, however, that various aspects and examples may have application in other types of cell stacks or flow batteries.Referring to the drawings, a redox flow battery 100 comprises a plurality of cell stack modules 102 (sometimes referred to as “cell stacks”). The cell stack modules 102 are electrically connected in series by way of electrical connectors 140. DC current generated while the battery 100 is in operation can be converted to AC by an inverter 142. Other electrical arrangements and configurations may be employed in other examples.

[0142] As shown in Figures 1 to 3, the cell stack modules 102 are fluidically connected in parallel. The battery includes a first tank 144, which is a reservoir for an anolyte 146, and a second tank 148, which is a reservoir for a catholyte 150.

[0143] A first anolyte manifold 152 is connected to the first tank 144 by a flow conduit 168. As shown in Figure 3, the flow conduit 168 comprises a flexible hose 191 that extends from the first tank 144 to the first anolyte manifold 152. At the first anolyte manifold 152 end, the flow conduit 168 terminates at a quickconnect coupling 192 that is coupled to a corresponding quick-connect coupling 193 on the first anolyte manifold 152.

[0144] A first catholyte manifold 153 is connected to the second tank 148 by a flow conduit 170. The flow conduit 170 comprises a flexible hose 194 that extends from the second tank 148 to the first catholyte manifold 153. At the first catholyte manifold 153 end, the flow conduit 170 terminates at a quick-connect coupling 195 that is coupled to a corresponding quick-connect coupling 196 on the first catholyte manifold 153.

[0145] The first anolyte manifold 152 distributes the anolyte 146 to the cell stack modules 102 by way of inlet conduits 156 (for clarity, only the inlet and outlet conduits for the rightmost cell stack module in Figure 1 are indicated with reference signs). Each inlet conduit 156 includes a flexible hose 160 that extends from the first anolyte manifold 152 to one of the cell stack modules 102. Each inlet conduit 156 terminates at a quick-connect coupling 162 that is releasably coupled to a corresponding quick-connect coupling 164 on the cell stack module 102.

[0146] The first catholyte manifold 153 distributes the catholyte 150 to the cell stack modules 102 by way of inlet conduits 158. As best shown in Figure 2,each inlet conduit 158 includes a flexible hose 166 that extends from the first catholyte manifold 153 to one of the cell stack modules 102. Each inlet conduit 158 terminates at a quick-connect coupling 167 that is coupled to a corresponding quick-connect coupling 169 on the cell stack module 102.

[0147] A second anolyte manifold 154 is connected to the first tank 144 by a return conduit 172. As best shown in Figure 3, the return conduit 172 comprises a flexible hose 198 that extends from the second anolyte manifold 154 to the first tank 144. At the second anolyte manifold 154 end, the return conduit 172 terminates at a quick-connect coupling 199 that is coupled to a corresponding quick-connect coupling 171 on the second anolyte manifold 154.

[0148] A second catholyte manifold 155 is connected to the second tank 148 by a return conduit 174. The return conduit 174 comprises a flexible hose 173 that extends from the second catholyte manifold 155 to the second tank 148. At the second catholyte manifold 155 end, the return conduit 174 terminates at a quick-connect coupling 175 that is coupled to a corresponding quick-connect coupling 177 on the second catholyte manifold 155.

[0149] The second anolyte manifold 154 receives the anolyte 146 from the cell stack modules 102 by way of outlet conduits 176. As best shown in Figure 2, each outlet conduit 176 includes a flexible hose 178 that extends from the cell stack module 102 to the second anolyte manifold 154. At the cell stack module 102 end, each outlet conduit 176 terminates at a quick-connect coupling 180 that is coupled to a corresponding quick-connect coupling 182 on the cell stack module 102.

[0150] The second catholyte manifold 155 receives the catholyte 150 from the cell stack modules 102 by way of outlet conduits 184. As best shown in Figure 2, each outlet conduit 184 includes a flexible hose 186 that extends from the cell stack module 102 to the second catholyte manifold 155. At the cell stack module 102 end, the outlet conduit 184 terminates at a quick-connect coupling 188 that is coupled to a corresponding quick-connect coupling 190 on the cell stack module 102.

[0151] Pumps (not shown) pump the anolyte 146 and catholyte 150 through an anolyte circuit and a catholyte circuit, respectively, within the cellstack modules 102. The direction of anolyte flow and of catholyte flow through each of the inlet and outlet conduits 156, 158, 176, 184 is indicated by arrows in Figure 2. The direction of anolyte flow and of catholyte flow through each of the flow and return conduits 168, 170, 172, 174 is indicated by arrows in Figure 3.

[0152] The quick-connect couplings 162, 164, 167, 169, 180, 182, 188, 190, 192, 193, 195, 196, 199, 171, 175, 177 can take the form of known quickconnect couplings. Alternatively, one or more of the quick-connect couplings 162, 164, 167, 169, 180, 182, 188, 190, 192, 193, 195, 196, 199, 171, 175, 177 can comprise any of the quick-connect couplings disclosed in this document. One or more of the quick-connect couplings 164, 169, 182, 190, 171, 177, 193, 196 can take the form of a female quick-connect coupling, advantages of which are described below. The female quick-connect coupling can be of a known type or can be a novel female quick-connect coupling incorporating one or more of the novel features of the examples of female quick-connect couplings described herein.

[0153] Operation of the battery 100 may be controlled in a known manner by a controller (not shown), details of which will not, for the sake of brevity, be described in this document.

[0154] Each cell stack module 102 comprises a first structural end plate 104 and a second structural end plate 106. The first end plate 104 and the second end plate 106 can be formed from any suitable material or materials, and by way of any suitable manufacturing process. For example, the first end plate 104 and the second end plate 106 can be cast or otherwise moulded from a metal, polymer(s), and / or any other suitable materials. Alternatively, the first end plate 104 and the second end plate 106 can be machined, additively manufactured, or otherwise produced from one or more materials and / or components.

[0155] As shown in the schematic diagram of Figure 4 (with the component shown slightly spaced apart for clarity), a stack of stack components 108 is sandwiched between the first end plate 104 and the second end plate 106. The stack components 108 include various elements that support the structural, electrical and fluidic requirements of the cell stack module 102. For example, the stack components 108 include various layers that together define a plurality ofbipolar cells arranged in series between the first end plate 104 and the second end plate 106. Potential structures and functions of the cell components 108 in a redox flow battery are known to the skilled person, and so will not be described in detail.

[0156] The stack components 108 include an isolator plate 112. In the illustrated example, the isolator plate 112 is disposed between the first end plate 104 and an adjacent one of the stack components 108. The isolator plate 112 is formed from an electrically insulating material and operates to electrically isolate the first end plate 104 from the adjacent stack component 108. The isolator plate 112 also provides fluidic distribution and sealing functions, as described in more detail below.

[0157] The isolator plate 112 is shown by itself in Figures 6 to 8. In the illustrated example, the isolator plate 112 is an injection moulded component. The isolator plate 112 is formed from polypropylene, but any other suitable polymer, other material, or combination of materials may be employed in other examples.

[0158] The isolator plate 112 comprises a planar region 114 for isolating, in use, the first end plate 104 from the adjacent stack component 108. As best shown in Figure 7, spaced apart ribs 116 extend over the side of the isolator plate 112 that is in contact with the adjacent surface of the first end plate 104. The ribs 116 help provide consistent contact between the isolator plate 112 and the first end plate 104. The ribs also provide additional stiffening without introducing overly thick regions, which may be undesirable in moulded polymer components.

[0159] The isolator plate 112 includes a first spigot 118 and a second spigot 120 disposed beside each other at a region adjacent to an upper edge of the isolator plate 112. The isolator plate 112 also includes a third spigot 122 and a fourth spigot 124 disposed beside each other at a region adjacent to a lower edge of the isolator plate 112. Each of the spigots 118 120, 122, 124 are the same as each other except for their locations.

[0160] For brevity, only the first spigot 118 will be described in detail. It will be appreciated that the description of the first spigot 118 can be applied to the other spigots 120, 122, 124. The first spigot 118 extends away from a plane of the planar region 114. In the illustrated example, the first spigot extends normally from the plane of the planar region 114. The first spigot 118 defines a fluidconduit extending through the planar region 114. That is, the first spigot 118 is effectively a tube that fluidically links the first end plate 104 side of the isolator plate 112 with the stack component 108 side of the isolator plate 112.

[0161] An outer surface 126 of the first spigot 118 may include a portion that tapers in a direction away from the planar region 114. In the illustrated example, the first spigot 118 tapers slightly along its entire length. As well as assisting in the attachment of the first spigot 118 to a quick-connect coupling as described below, the taper also assists in withdrawal of the isolator plate 112 from a mould following injection moulding of the isolator plate 112.

[0162] The isolator plate 112 includes axially-extending sleeves 128, one disposed adjacent each lateral side of the isolator plate 112. As best shown in Figure 4, the sleeves 128 extend through corresponding respective apertures 130 formed at corresponding positions in the first end plate 104. In the assembled cell stack module 102, electrical terminals 322 extend through the sleeves 128. The electrical terminals 322 are for termination of the connections 140 shown in Figure 1.

[0163] Figure 6 shows the other side of the isolator plate 112, showing various sealing and fluid-directing features (not indicated with reference signs). The sealing and fluid-directing features are not essential to an understanding of aspects or examples of the invention, and so will not be described in detail.

[0164] Because the isolator plate 112 is moulded in one piece from polypropylene, the first spigot 118 is formed from polypropylene. Polypropylene is a weldable polymer. Upon heating to a sufficient temperature, polypropylene melts. When melted, the polypropylene can be brought into contact with another component and held in place while the melted polypropylene solidifies. When the surface of the other component is formed from a compatible substance, the polypropylene welds itself to that surface. To improve such welds, both the polypropylene and the material of the other surface can be melted before being brought together. Welding of this type is generally considered to form a permanent connection, due to fusing of the materials while the polypropylene is in a melted state.In other examples, the isolator plate 112 can be moulded from another weldable polymer. In yet other examples, the isolator plate 112 can be formed from more than one material, with only the spigots 118, 120, 122, 124 being formed from a weldable polymer. In yet other examples, only that portion of the spigots 118, 120, 122, 124 that are to be welded are formed from a weldable polymer. For example, only an outer surface of the spigots can be formed from a weldable polymer.

[0165] Any form of polymer welding may be employed. For example, fusion welding is used in the illustrated example, as described in more detail below.

[0166] In other implementations, the spigots (or at least portions of the spigots that are to be connected to a quick-connect coupling as described in more detail below) can be formed from a solvent-weldable polymer.

[0167] A further isolator plate (not shown) forms part of the stack components 108. The further isolator plate is positioned between the second end plate 106 and the rest of the stack components 108. In this embodiment, the further isolator plate does not include any spigots, as all fluidic connections are made through the first end plate 104 via the isolator plate 112. In other implementations, the further isolator plate may include one more spigots, which may be the same as, or similar to, any of the spigots (or their alternatives) as described herein.

[0168] As best shown in Figure 4, when the cell stack module 102 is assembled with the planar region 114 sandwiched between the first end plate 104 and the adjacent stack component 108, the spigots 118, 120, 122, 124 extend through corresponding respective apertures in the first end plate 104 (only apertures 132 and 134 are referenced - see Figure 4). The spigots 118, 120, 122, 124 are dimensioned such that they extend outwards from the outer surface of the first end plate 104. This allows a quick-connect coupling to be attached to each spigot, as described in more detail below.

[0169] Although the isolator plate 112 includes four spigots, in other implementations, more or fewer spigots may be employed (with a corresponding adjustment of the number of apertures through the end plate 104). Similarly,although no spigots pass through the end plate 106, in other implementations, one or more spigots may be provided at the end plate 106 end of the cell stack 102. As one non-limiting example, two spigots may be provided through the end plate 104 and two spigots may be provided through the end plate 106.

[0170] Turning to Figures 10 to 12, there is shown a quick-connect coupling 200. In the illustrated example, the quick-connect coupling 200 is configured for permanent attachment to one the spigots 118, 120, 122, 124.

[0171] In the illustrated example, the quick-connect coupling 200 takes the form of a female quick-connect coupling 200. The female quick-connect coupling 200 is configured to allow quick, releasable connection of a complementary male quick-connect coupling, as described below. In other implementations, the quickconnect coupling can take the form of a male quick-connect coupling.

[0172] The quick-connect coupling 200 comprises a body 202. The body 202 defines an internal through conduit 204. The internal conduit 204 extends along a longitudinal axis 210 within the body 202.

[0173] A first end 206 of the body 202 is intended for connection to one of the spigots 118, 120, 122, 124. In the illustrated example, the first end 206 includes a portion 208 having a radially-inner surface that has a profile complementary to that of the outer surface 126 of the spigot to which the quickconnect coupling 200 is to be attached, as described below. A second end 272 of the body 202 opposite to the first end 206 is intended for connection to a complementary male quick-connect coupling, as also described below.

[0174] In the illustrated example, the quick-connect coupling 200 is intended to be permanently connected to the first spigot 118. Accordingly, the inner surface of the portion 208 diverges in cross section in a direction towards the axially outer end of the first end 206. The angle of the divergence corresponds with the taper angle of the corresponding portion of the outer surface 126 of the first spigot 118. The use of the same (or at least a similar) angle for the mating portions may help with centring of the quick-connect coupling 200 relative to the spigot 118, 120, 122, 124 while they are being connected (e.g., fusion welded). The use of the same (or at least a similar) angle for the mating portions may also improve the strength of the fusion weld (where fusion welding is employed).The radially-inner surface of the portion 208 may comprise a weldable polymer, such as a fusion-weldable polymer. The body 202 is moulded from such a polymer. Alternatively, the radially-inner surface of the portion 208 may be formed from such a polymer, with the rest of the body being formed from another material. In the illustrated example, the body is moulded from polypropylene.

[0175] In the illustrated embodiment, the first end of the quick-connect coupling is configured for permanent connection to a corresponding spigot by way of fusion welding. In other implementations, the first end may be configured for permanent connection to a corresponding spigot by way of other mechanisms, such as bonding or solvent welding. In yet other implementations, the first end may be configured for releasable connection to a corresponding spigot. For example, an inner or outer surface of the first end may be threaded, allowing the quick-connect coupling to be screwed onto a corresponding complementary thread formed on or in the spigot. In other implementations, the first end may include a flange, allowing it to be clamped to a corresponding flange on the spigot. Other means of permanent and temporary connection of the quick-connect coupling to a corresponding spigot will suggest themselves to the skilled person.

[0176] As explained in more detail below, when the body 202 is attached to the spigot 118, the internal conduit 204 is in fluid communication with the fluid conduit defined by the spigot 118.

[0177] The quick-connect coupling 200 comprises a circumferentially-extending radially-outer wall 212. The outer wall 212 is generally cylindrical with a slight taper in a direction away from the axially outer end of the first end 206. Other cross-sectional and longitudinal profiles may be used in other examples. The outer wall 212 includes a radially-extending mounting component in the form of a flange 214 adjacent to the axially outer end of the first end 206. The flange 214 includes four axial apertures 286, each of which is configured for receiving a fastener 280 (as described below) to fasten the quick-connect coupling 200 to a corresponding threaded boss 282 on the end plate 104.

[0178] The quick-connect coupling 200 also comprises a circumferentially-extending radially-inner wall 216. The inner wall 216 isconnected to the outer wall 212 at a position 218 distal to the axially outer end of first end 206. The inner wall 216 extends from the position 218 towards the axially outer end of the first end 206.

[0179] The outer wall 212 and the inner wall 216 define an annular space 220 between them. The annular space 220 is open adjacent to the axially outer end of the first end 206. The annular space 220 may have any suitable shape in radial section. For example, the annular space 220 may be V- or U-shaped in radial section.

[0180] The quick-connect coupling 200 includes a radially-inner O-ring sealing surface 224. In the illustrated example, the O-ring sealing surface 224 is axially dimensioned to accept a first O-ring 226 and an axially-adjacent second O-ring 228. In other examples, the O-ring sealing surface is axially dimensioned to accept only a single O-ring. In yet other examples, the O-ring sealing surface is axially dimensioned to accept three or more O-rings.

[0181] In the illustrated example, in addition to the first and second O-rings 226, 228, the O-ring sealing surface 224 is axially dimensioned to accept an O-ring spacer 230 positioned between the first O-ring 226 and the second O-ring 228. The O-ring spacer 230 prevents the first O-ring 226 from coming into contact with the second O-ring 228. This may reduce the chance of any contamination of the first O-ring 226 reaching the second O-ring 228. In addition, the first O-ring 226 can operate as a wiper, cleaning the outer surface of a male quick-connect coupling as it is inserted into the quick-connect coupling 200. This may be of particular use where contamination from, e.g., electrolyte, electrolyte crystals, environmental detritus, or the like, may be present during maintenance or repair of the cell stack module 102.

[0182] The quick-connect coupling 200 is configured to accept a sealretainer 232. The seal -retainer 232 is configured to retain the first and second O-rings 226, 228 in their installed positions. As best shown in Figures 14 and 16, the seal-retainer 232 is an annular component having a seal-side axial surface 234 for engaging an axially-adjacent one of the at least one O-rings. The seal-retainer 232 also includes a first radially-extending tooth 236, and a second radially-extending tooth 238 positioned diametrically opposite the first radially-extending tooth 236.The seal-retainer 232 includes a radially-outwardly facing shelf 240. In the illustrated example, the shelf 240 extends around the entire circumference of the seal-retainer 232. In other implementations, the shelf extends circumferentially only along regions adjacent to the respective teeth 236, 238.

[0183] The body 202 comprises an axial stop 242 within the internal conduit 204. The stop 242 is configured to impede or prevent, in use, axial movement of the second O-ring 228 (and hence the spacer 130 and the first O-ring 226) beyond its installed position, as described in more detail below.

[0184] In the illustrated example, the quick-connect coupling 200 includes a first locating feature. The first locating feature is formed by a narrowed portion of the internal conduit 204 and comprises, in radial section, a ramp 244. In use, the ramp 244 is configured to engage a distal end of a male quick-connect coupling coupled within the quick-connect coupling 200, as described in more detail below.

[0185] In the illustrated example, the quick-connect coupling 200 also includes a second locating feature 246. The second locating feature 246 comprises a radially-inner surface of the outer wall 212 adjacent to the axially outer end of the second end 272 of the body 202. In use, the second locating feature 246 is configured to engage a radially-outer surface of a corresponding feature of a male quick-connect coupling coupled within the quick-connect coupling 200, as described in more detail below. The second locating feature 246 is on an axially opposite side of the O-rings 226, 228 relative to the first locating feature (i.e., the ramp 244).

[0186] The body 202 includes a retention feature for retaining the sealretainer 232. In the illustrated example, the retention feature comprises a first radially-extending opening 248 for receiving the first tooth 236. The retention feature also comprises a second radially-extending opening 250 positioned diametrically opposite the first radially-extending opening 248, for receiving the second tooth 238.

[0187] In the illustrated example, the first opening 248 and the second opening 250 take the form of through openings that extend to an outer surface of the body 202. The first opening 248 is positioned such that, when the quickconnect coupling 200 is installed onto the first spigot 118 at the predeterminedorientation shown in Figures 13 to 15, any fluid can drain through the first opening 248.

[0188] The second end 272 of the body 202 comprises a first key way in the form of an axially-extending recess 274. The recess 274 extends from the axially outer end of the second end 272. The recess 274 is circumferentially aligned with the radially-extending opening 248. The recess 274 terminates at a ramp 276. The recess 274 is configured to axially guide the tooth 236 as the sealretainer 232 is inserted into the body 202, as described in more detail below.

[0189] The body comprises a second keyway in the form of an axially-extending recess 278 positioned diametrically opposite to the axially-extending recess 274. The second keyway is structurally and functionally the same as the first key way, so will not be described in detail.

[0190] The quick-connect coupling 200 comprises a retaining clip 252 for retaining a male quick-connect coupling coupled within the quick-connect coupling 200, as described in more detail below. The retaining clip 252 is a generally U-shaped component formed from bent stainless steel wire. The retainer clip 252 has straight legs 254 extending downwards from a semi-circular base 256. Each of the legs 254 terminates at a short axially-extending portion 270, which acts to prevent the retaining clip 252 being removed from the body 202 unless intended by a user.

[0191] The outer surface of the body 202 includes a circumferentially-extending first channel 258 formed in one side of the outer wall 212, and a circumferentially-extending second channel 260 formed in the diametrically opposite side of the outer wall 212. Central regions of the respective first and second channels 258, 260 are open to the inside of the outer wall 212.

[0192] The first channel 258 and the second channel 260 extend upwards along the outer surface of the body 202. Moving upwards along the body 202, the first channel 258 and the second channel 260 become shallower. Near the top of the body 202, the first channel 258 becomes defined by a first pair of parallel ribs 262, and the second channel 260 becomes defined by a second pair of parallel ribs 264. The ribs 262, 264 terminate near the top of the body 202, leaving a gap between the adjacent ends of the ribs 262, 264.On a lower region of the body 202, a recess 266 extends along the first channel 258. The recess 266 includes a landing region 268, for holding the retaining clip 252 in the open position, as described in more detail below.

[0193] The retaining clip 252 is retained within the channels 258, 260. The retaining clip 252 can be moved between a closed position (as shown in Figures 10 to 15) and an open position (not shown). When the retaining clip 252 is in the open position, a male quick-connect coupling can be disconnected from the quickconnect coupling 200. When the retaining clip 252 is in the closed position, a male quick-connect coupling can be connected to, but not disconnected from, the quickconnect coupling 200, as described in more detail below.

[0194] As best shown in Figure 14, the quick-connect coupling 200 includes a ridge 222 extending circumferentially around a radially-inner surface of the internal conduit 204. The ridge 222 is positioned between the axially outer end of the first end 206 and O-ring sealing surface 224. The ridge 222 is configured to inhibit axial movement of molten polymer from the welding region, during welding of the quick-connect coupling 200 to the spigot 118, 120, 122, 124.

[0195] A male quick-connect coupling 300 will now be described with reference to Figure 15. The male quick-connect coupling 300 includes a hollow body 302 that defines an internal conduit 304. The body 202 is attached to a flexible fluid conduit 306 in a conventional manner.

[0196] A distal end of the body 302 terminates at a nose portion 308, which is at least partly defined, in radial section, by a ramp 310. The ramp 310 is configured to engage with the corresponding ramp 244 formed within the body 202, as described in more detail below.

[0197] Axially-adjacent to the nose portion 308, an outer surface of the body 302 includes a seal-engaging surface 312 for engaging the radially-inner surfaces of the O-rings 226, 228, as described in more detail below.

[0198] Moving axially away from seal-engaging surface 312, the body 302 includes, in radial section, an alignment ramp 314. The alignment ramp 314 is configured to align the male quick-connect coupling 300 with the quick-connect coupling 200 during connection. The alignment ramp 314 is also configured toradially displace the exposed legs 254 of the retaining clip 252 as the male quickconnect coupling 300 is inserted into the quick-connect coupling 200.

[0199] The body 302 includes, in radial section, a valley 316 defined between a radially-extending axial terminus of the alignment ramp 314 and a first circumferentially-extending rib 318. The valley 316 is configured to receive the exposed legs 254 of the retaining clip 252 as the male quick-connect coupling 300 reaches its installed position during insertion into the quick-connect coupling 200. The retaining clip 252 is retained within the valley 316, preventing disconnection of the male quick-connect coupling 300 from the quick-connect coupling 200.

[0200] The body 302 then includes a second circumferentially-extending rib 320 axially spaced from the first circumferentially-extending rib 318. An outer edge of the second circumferentially-extending rib 320 is configured to interact with the second locating feature 246 (i.e., the radially-inner surface of the outer wall 212 adjacent to an end of the body 202 opposite that of the first end).

[0201] Referring to Figures 19 to 23, there is shown a structural end plate 400. The end plate 400 can be, for example, a structural end plate for a stackbased flow battery, such as the first or second end plate 104, 106 for use with the redox flow battery 100. The end plate 400 need not include, for example, the apertures 132, 134, 136, 138 of the first end plate 104. The end plate 400 can have any number of such apertures, including zero such apertures.

[0202] The end plate 400 includes a planar region 402. The planar region 402 can correspond to, for example, the planar region 114 of the first end plate 104. The planar region 402 includes a first edge 404 and a second edge 406. In the illustrated example, the first edge 404 and the second edge 406 are generally straight and parallel to each other. In other implementations, the first edge 404 and the second edge 406 may be curved, or have any other profile in plan view. In the illustrated example, the first edge 404 and the second edge 406 are upper and lower edges of the planar region 114. In other implementations, the first edge 404 and / or the second edge 406 may be another edge of the planar region 114, including an upper edge, a lower edge, a lateral edge, or any other edge at any angle and having any shape.The end plate 400 includes four reinforcing structures in the form of a first beam 408, a second beam 410, a third beam 412, and a fourth beam 414. Each of the beams 408, 410, 412, 414 extends across a surface of the planar region 402 between the first edge 404 and the second edge 406.

[0203] The beams 408, 410, 412, 414 are structurally and functionally similar to each other, and hence only the beam 408 will be described in detail. As best shown in Figures 21 and 22, the beam 408 extends away from an outer surface of the planar region 402, on an outer side of the planar region 402 when the end planar region 402 is installed on a cell stack module, such as the cell stack module 102. In plan view (i.e., looking directly into the outer surface of the planar region 402), the beam 408 extends across the planar region 402 at right angles to both the first edge 404 and the second edge 406.

[0204] The end plate 400 includes a first landing surface 416 disposed at a first end of the first beam 408 adjacent to the first edge 404. The end plate 400 includes a second landing surface 418 disposed at a second end of the first beam 408 adjacent to the second edge 406. As described in more detail below, the first landing surface 416 and the second landing surface 418 are configured to receive, in use, force from fasteners, the forces being in a direction to cause compression of the cell stack module.

[0205] As best shown in Figure 21, the first landing surface 416 and the second landing surface 418 are positioned closer to a first plane 420 than to a second plane 422. The first plane 420 is defined by an outer surface of the planar region. The second plane 422 is parallel to the first plane 420 and passes through a region 424 of the first beam 408 that is furthest from the first plane 420.

[0206] In the illustrated example, the first landing surface 416 and the second landing surface 418 are positioned within 5 mm of the first plane 420. In other examples, a first ratio of: a distance between the first landing surface and the first plane; to a distance between the first landing surface and the second plane; is less than 0.2; and a second ratio of: a distance between the second landing surface and the first plane; to a distance between the second landing surface and the second plane; is less than 0.2.The first beam 408 includes a further region 426 between the first edge 404 and the second edge 406. The further region 426 may be, for example, centered at a position equidistant between the first edge 404 and the second edge 406. As best shown in Figure 20, in the further region 426 (and in cross-section), a first dimension 428 of the first beam 408 measured in a direction normal to the first plane 420 is greater than a second dimension 430 of the beam measured across a width of the first beam 408.

[0207] The first beam 408 includes a first transition region 432 adjacent to the first end of the first beam 408 and a second transition region 434 adjacent to the second end of the first beam 408. As best shown in Figures 20 and 21, within the first transition region 432 and the second transition region 434, a dimension of the first beam 408 measured in a direction normal to the first plane 420 diminishes with distance from a mid-point of the first beam 408 between the first edge 404 and second edge 406. That is (and as shown in Figure 21), the height 458 of the first beam 408 as viewed from the side of first beam 408 reduces within the first transition region 432 and the second transition region 434, in a direction away from the midpoint of the first beam 408.

[0208] As best shown in Figure 20, within the first transition region 432 (and in plan view looking into the plane of the end plate 400), the first beam 408 bifurcates into a first bifurcated structure 436. Similarly, within the second transition region 434 (and in plan view looking into the plane of the end plate 400), the first beam 408 bifurcates into a second bifurcated structure 438.

[0209] In the illustrated example, the first and second bifurcated structures 436, 438 are generally C-shaped in plan view looking into the plane of the end plate 400, with the open end of the C facing directly away from a mid-points of the first beam 408. In this way, the first beam 408 takes, in plan view, a visual form approximating that of symmetrical double-ended open spanner.

[0210] In plan view looking into the plane of the end plate 400, the first bifurcated structure 436 surrounds the first landing surface 416. Similarly, in plan view looking into the plane of the end plate 400, the second bifurcated structure 438 surrounds the second landing surface 418. The positioning of the first and second landing surfaces 416, 418 within the respective first and second bifurcatedstructures 436, 438 assists with rigidity and with the smooth transfer of force between the landing structures and the beam, and hence the end plate 400.

[0211] The first landing surface 416 includes an aperture 440 and the second landing surface 418 includes an aperture 442. The apertures 440 and 442 are configured for receiving a fastener, as described in more detail below.

[0212] In the illustrated example, the end plate 400 includes four of the beams 408, 410, 412, 414, and the beams extend parallel to each other. In other examples, the number of beams may be greater or fewer. In other examples including at least two of the beams, the beams need not be parallel to each other. The skilled person can select the number, configuration, and orientation of the beams to suit the particular application.

[0213] The end plates 104, 106, 400 include a reinforcing ridge 444 formed on an outer surface of the end plate 104, 106, 400. In plan view (i.e., looking into the surface of the end plate 104, 106, 400), the reinforcing ridge 444 takes the form of a pinched or slightly squashed stadium or obround shape. The reinforcing ridge 444 crosses each of the beams 408, 410, 412, 414 twice, at positions adjacent to the respective first and second edges 404, 406. The location, height, shape, and position of the reinforcing ridge 444 is selected to stiffen the end plate 104, 106, 400, and to assist in transferring between the end plate 400, the planar region 114, the beams 408, 410, 412, 414, and the landing surfaces 416, 418.

[0214] The end plate 400 includes two eyelets 446, 448. The eyelets, in use, allow lifting of the cell stack module to which the end plate 106, 108, 400 is installed. The eyelets 446, 448 are disposed above the first edge 404, and extend laterally from the first transition regions 432 of the second and third beams 410, 412. Each eyelet 446, 448 is formed by an element 450 that extends laterally from the edge of the first transition regions 432, curving down to meet the first edge 404. The element 408 continues as a ridge along the surface of the end plate 104, 106, 400, extending until it meets the ridge 444. This arrangement helps with transfer and distribution of loads between the eyelets 446, 448 and the planar region 402. In the illustrated example, each eyelet 446, 448 defines an aperture that extends within, or adjacent to, the plane 420.In other examples, a hook (not shown) may be provided in place of the eyelets 446, 448. The difference between an eyelet and a hook is that an eyelet includes a closed aperture whereas a hook is open. For a given dimension, an eyelet may be stronger than a similarly dimensioned hook, due to the transfer of loads between both ends of the element defining the eyelet. A hook, however, may be grabbed by a closed lifting element, which may be preferable in certain circumstances.

[0215] Although two eyelets 446, 448 are shown, it will be appreciated that a different number of eyelets (or hooks) may be provided in other examples.

[0216] As with the first and second end plates 104 and 106, the end plate 400 can be formed from any suitable material or materials, and by way of any suitable manufacturing process. For example, the end plate 400 can be cast or otherwise moulded from a metal, polymer(s), and / or any other suitable materials. Alternatively, the end plate 400 can be machined, additively manufactured, or otherwise produced from one or more materials and / or components

[0217] or otherwise moulded from a metal and / or a polymer. Alternatively, the end plate 400 may be machined, additively manufactured, or otherwise produced from one or more materials and / or components.

[0218] Assembly of a cell stack module for use in a redox flow battery will now be described with reference to Figures 3 and 4.

[0219] The isolator plate 112 and the stack components 108 are assembled into a stack, with the spigots 118, 120, 122, 124 facing away from the stack components 108. The first end plate 104 / 400 is positioned relative to the isolator plate 112 such that the spigots 118, 120, 122, 124 are aligned with their respective apertures 132, 134, 136, 138 in the first end plate 104 / 400. The first end plate 104 / 400 is axially slid into contact with the planar region 114, with the spigots 118, 120, 122, 124 extending through their respective apertures 132, 134, 136, 138. The second end plate 106 / 400 is positioned at the other end of the stack components 108.

[0220] Threaded rods 452 are passed through corresponding pairs of the apertures 440, 442, resulting in the arrangement of Figure 4. A hydraulic press (not shown) is used to push the first end plate 104 / 400 and the second end plate106 / 400 towards each other, thereby to compress the cell stack module 102. While the cell stack module 102 is compressed, springs 460 are slid over the threaded rods 452 and nuts 456 are screwed onto the ends of the threaded rods 452 before the hydraulic press is released.

[0221] Loads are distributed between the beams 408, 410, 412, 414, their associated first and second bifurcated structures 436, 438, the landing surfaces 416, 418, and the threaded rods 452. The position of the landing surfaces 416, 418 relative to the first plane 420 allows for threaded rods 452 of reduced length to be used. If the overall length of the cell stack module 102 is defined by the threaded rods 452, then the position of the landing surfaces 416, 418 relative to the first plane 420 allows for a reduced overall length of the cell stack module. Particularly where the end plates 104, 106, 400 are formed from cast metal or another relatively heavy material, the reduced amount of material in and around the landing surfaces 416, 418 may contribute to a reduced overall weight of the end plates 104, 106, 400 as well as lower material costs.

[0222] One of the quick-connect couplings 200 is then installed on each of the spigots 118, 120, 122, 124. This is done by fusion welding each of the quickconnect couplings 200 to a corresponding one of the spigots 118, 120, 122, 124. Once the tapered outer surface 126 of one of spigots 118, 120, 122, 124 and the correspondingly angled radially-inner surface of the portion 208 of the body 202 are melted, the quick-connect coupling 200 is pushed axially into the spigot 118, 120, 122, 124. The melted material melds together, fusion welding the quickconnect coupling 200 to the corresponding spigot 118, 120, 122, 124. During this process, the ridge 222 impedes flow of any escaped melted polymer towards the O-ring sealing surface 224.

[0223] The tapered outer surface 126 of each spigot 118, 120, 122, 124 and the correspondingly angled radially-inner surface of the portion 208 of the body 202 assist with centring of the coupling 200 on its corresponding spigot 118, 120, 122, 124 as the components are brought together during the welding process. Fusion welding offers a fast and reliable method of providing a strong, permanent connection between polymer components., A fastener 280 is inserted through each of the apertures 174 in the flange 214 and screwed into the corresponding threaded boss 282. Once tightened, the four fasteners 280 hold the flange 214, and hence the outer wall 212, firmly against the first structural endplate 104. The annular space 220 between the inner wall 216 and the outer wall 212 partly decouples the inner wall 216, and hence the spigot 118, 120, 122, 124, from lateral and other forces received by the outer wall 212. This includes forces applied as a result of direct contact with the outer wall 212, but also forces applied indirectly via the male quick-connect coupling 300. This decoupling reduces the chance of damage to the spigots 118, 120, 122, 124 and / or the isolator plate 112, which is advantageous given the challenges that may be associated with replacement of the isolator plate 112.

[0224] The decoupling provided by the annular space 220 also reduces forces on the planar region 114 around the base of the spigot 118, 120, 122, 124 due to lateral forces applied to the spigot. This may be advantageous when a region around the base of the spigot defines a sealing surface for an adjacent stack component 108.

[0225] Once the quick-connect coupling 200 has been welded to the corresponding spigot 118, 120, 122, 124, the second O-ring 228, the spacer 230, and the first O-ring 226 can be installed. Alternatively, the quick-connect coupling 200 may be welded to the corresponding spigot 118, 120, 122, 124 with the second O-ring 228, the spacer 230, and the first O-ring 226 pre-installed If the retaining clip 252 is pre-installed on the quick-connect coupling 200, it is moved into the open position. A simple tool, such as a flat-bladed screwdriver, can be used to prise the base 256 upwards, disengaging the retaining clip 252 from between the first and second ribs 262, 264 holding it in place. The retaining clip 232 can then be manually moved into the fully open position.

[0226] The second O-ring 228, the spacer 230, and the first O-ring 226 are installed by pushing them axially into the second end 272 of the body 202. The stop 242 prevents axial movement of the second O-ring 228 (and hence the spacer 130 and the first O-ring 226) beyond its intended installation position.

[0227] The seal-retainer 232 is then installed. First, the seal-retainer 232 is rotationally orientated such that the first and second teeth 236, 238 are alignedwith the corresponding key ways 274, 278. The seal-retainer 232 is then pushed axially into the second end 272. The seal-retainer 232 is guided by the interaction of the teeth 236, 238 and the corresponding keyways 274, 278.

[0228] When the teeth 236, 238 reach the ramp 276 the end of each key way 274, 278, further axial movement of the seal-retainer 232 causes the teeth 236, 238 to be pushed radially inwards due to their interaction with the ramp 276. This causes radial deformation of the seal-retainer 232, allowing the teeth 236, 238 to ride up the ramp 276, and the seal-retainer 232 to continue moving axially. When the teeth 236, 238 reach the respective first and second openings 248, 250, the radially outward force due to the resilience of the seal-retainer 232 causes the teeth 236, 238 to drop into the respective first and second openings 248, 250, which prevents the seal-retainer 232 from being pushed out of the body 202 when the quick-connect coupling 200 is in use.

[0229] The retaining clip 252 is then returned to the closed position (or installed, if the retaining clip 252 had not been pre-installed).

[0230] The assembled cell stack module 102 can be installed in a redox flow battery (such as the battery 102). The eyelets 446, 448 may be used to lift the cell stack module 102 using a crane (not shown) or other lifting equipment.

[0231] Installation of the cell into the redox flow battery can also take place at any other time, such as before installation of the quick-connect coupling 200 onto the spigots 118, 120, 122, 124.

[0232] Before, during, or after assembly of the redox flow battery, one or more fluid connectors may be connected to the cell stack module 102 by way of the quick-connect coupling 200. A distal end of the male quick-connect coupling 300 is inserted into the quick-connect coupling 200. The alignment ramp 314 engages the portions of the retaining clip 252 that extend within the body 202 of the quick-connect coupling 200. The alignment ramp pushes the legs 254 of the retaining clip 252 apart as the male quick-connect coupling 300 is pushed further into the quick-connect coupling 200.

[0233] As the male quick-connect coupling 300 approaches its final installation position, at least one radial side of the nose portion 308 of the male quick-connect coupling 300 engages the ramp 244 formed within the body 202,which helps to centre the nose portion 308 with the body 202. Further axial movement causes the ramp 310 to engage the ramp 244. During this movement, at least a portion of the first circumferential rib 318 engages the inside of the body 202, which again helps to centre the adjacent portion of the male quick-connect coupling 300 relative to the body 202. Further axial movement causes at least a portion of the second circumferential rib 320 to similarly engage the inside of the body 202, further helping to centre the adjacent portion of the male quick-connect coupling 300 relative to the body 202.

[0234] As the nose portion 308, the ramp 310, the first circumferential rib 318, and the second circumferential rib 320, are engaging corresponding internal surfaces within the body 202, the ramp 310 moves past the legs 254 of the retaining clip 252. The legs 254 then drop into the valley 316 behind the ramp 310. This sound of the legs clicking into the valley may provide audible confirmation that the male quick-connect coupling 300 is properly seated within the quick-connect coupling 200. The legs 254 being retained within the valley 316 prevent removal of the male quick-connect coupling 300 from the big-connect coupling 200.

[0235] In the event of an electrolyte leak past the O-rings 226, 228, the electrolyte will tend to drain through the opening 248 rather than move outwards into contact with the legs 254 of the retaining clip 252. Even though the retaining clip 252 is made from stainless steel in the illustrated example, certain electrolytes in certain charge states may cause undesirable degradation of the retaining clip 252.

[0236] If any electrolyte leaks past the opening 250, then the keyway 274 will direct it away from the legs 254 of the retaining clip 252, and out of the quick-connect coupling 200.

[0237] In other examples, the retaining clip 252 may be replaced by a plastic component offering similar functionality with a lower risk of degradation in the event of electrolyte spillage or leakage.

[0238] As best shown in Figure 14, the seal-retainer 232 and the male quick-connect coupling 300 are configured such that, in the event one or both of the teeth 236, 238 break or disengage from their corresponding openings 248, 250in use, the seal-retainer 232 engages the ramp 314 on the male quick-connect coupling 300. The ramp 314 prevents the seal-retainer 232 from moving any further axially away from the first end 206, which may reduce or prevent leakage of electrolyte due to unconstrainted axial movement of the O-rings 226, 228.

[0239] Turning to Figure 17, there is shown a cell stack module 500 for a redox flow battery (such as the redox flow battery 102). The cell stack module 500 includes two female quick-connect couplings 502 extending from or through an end plate 504 of the cell stack module 500. The quick-connect couplings 502 are configured to allow connection and disconnection of a complementary male quick-connect fluid coupling.

[0240] The quick-connect couplings 502 can, for example, comprise a quick-connect coupling as described herein, such as the quick-connect coupling 200. Alternatively, the quick-connect coupling can be a prior art quick-connect coupling. While two female quick-connect couplings 502 are shown, more or fewer female quick-connect couplings 502 may be provided in other examples.

[0241] Turning to Figure 18, there is shown a fluid-carrying component 600 for use in a redox flow battery such as the redox flow battery 100 for example. The fluid-carrying component 600 is configured for connection to a flexible fluid conduit 602. The fluid-carrying component 600 includes a housing 604 comprising an internal fluid path and / or an internal fluid reservoir 606, examples of which are described below.

[0242] The fluid-carrying component 600 includes a fluid connector 608 in fluid communication with the internal fluid path and / or the internal fluid reservoir 606. The fluid connector 608 extends outside the housing 602. The fluid connector 608 comprises a female quick-connect coupling 610 for receiving a complementary male quick-connect coupling 612 coupled to the end of the flexible fluid conduit 602.

[0243] In an example, the fluid-carrying component 600 takes the form of a cell stack for a redox flow battery (such as the redox flow battery 100, for example). The cell stack module 102 is one example of such a cell stack, but other cell stacks may be employed. In a cell stack, the internal fluid path and / or the internal fluid reservoir 606 can include one or more reservoirs, and / or one or morepaths, for distribution of electrolytes through the cell stack during operation of the battery 100.

[0244] In another example, the fluid-carrying component 600 takes the form of a manifold for a redox flow battery (such as the redox flow battery 100, for example). The first and second manifolds 152, 154 are examples of such manifolds, but other manifolds may be employed. In a manifold, the internal fluid path and / or the internal fluid reservoir 606 can include one or more reservoirs, and / or one or more paths for distribution of electrolytes to the cell stacks during operation of the battery 100.

[0245] In general, on a male quick-connect coupling, the outer surface of the portion of the male quick-connect coupling that engages a corresponding female quick-connect coupling is relatively exposed when compared with the corresponding inner surface of the female quick-connect coupling. As such, it is more likely that the outer surface of the male quick-connect coupling will be damaged during installation and / or maintenance involving the connection and disconnection of the quick-connect couplings to and from each other.

[0246] Where the quick-connect coupling is relatively easy to replace, the risk of damage may be of lower concern. However, if the quick-connect coupling is to be attached (and particularly permanently attached) to a difficult and / or expensive to replace component, it is preferable to use a female quick-connect coupling, the sealing surface of which is less likely to be damaged than a corresponding male quick-connect coupling.

[0247] In the context of certain examples described in this document, the isolator plate 112 and the manifolds 152, 154 are relatively difficult to replace once the battery is deployed. Even if the isolator plate 112, for example, is not an expensive component relative to the total cost of the battery, considerable time and disruption may be involved in its replacement. The battery must be taken offline, and significant dismantling of the battery 100 and cell stack module 102 must be undertaken in order to access the isolator plate 112 for replacement. It may also be challenging to reassemble the cell stack module 102, given that a hydraulic press is generally required. The manifolds 152, 154 are also difficult to replace given their size and location within the battery 100. A flexible conduit, in contrast,is typically easier to replace. Accordingly, by providing a female quick-connect coupling on the fluid-carrying component that is more difficult to access and / or dismantle, maintenance costs may be reduced.

[0248] Previous examples describe a permanent connection between the female quick-connect coupling and the housing 604. In other examples, the female quick-connect coupling can be attached to the housing 604 (including, for example, a cell stack such as the cell stack module 102, or a manifold such as the first and / or second manifolds 142. 154) by way of a releasable connection. For example, a threaded, clamped, or other releasable connection type can be used to connect the female quick-connect coupling to a spigot or other inlet / outlet on the housing 604.

[0249] Further aspects and / or embodiments of the invention are described in the following clauses:

[0250] Clause 1. An isolator plate for assembly between a structural end plate and a stack component in a cell stack for a redox flow battery, the isolator plate comprising:

[0251] a planar region for isolating, in use, the structural end plate from the stack component; and

[0252] a spigot extending away from a plane of the planar region, the spigot for extending, in use, through an aperture in the structural end plate, the spigot defining a fluid conduit extending through the planar region.

[0253] Clause 2. The isolator plate of clause 1, wherein an outer surface of the spigot includes a portion that tapers in a direction away from the planar region.

[0254] Clause 3. The isolator plate of clause 1 or clause 2, wherein at least an outer surface of an end region of the spigot is formed from a weldable polymer, the end region of the spigot distal to the planar region.

[0255] Clause 4. The isolator plate of any one of the preceding clauses, wherein at least an outer surface of the spigot that, in use, extends beyond the aperture on a side of the structural end plate opposite the side on which the planar region of the isolator plate is disposed is formed from a weldable polymer.Clause 5. The isolator plate of any one of the preceding clauses, moulded from a polymer.

[0256] Clause 6. A coupling configured for permanent attachment to the spigot of any one of the preceding clauses, the coupling defining an internal conduit and comprising:

[0257] a first end configured for attachment to the spigot; and a second end configured to allow releasable connection of a complementary fluid connector.

[0258] Clause 7. The coupling of clause 6, wherein a portion of the body, intended for connection to the spigot, defines a radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached.

[0259] Clause 8. The coupling of clause 7, wherein the radially-inner surface comprises a weldable polymer.

[0260] Clause 9. The coupling of clause 7 or clause 8, wherein the internal conduit extends along a longitudinal axis within the body, the coupling comprising:

[0261] a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to a structural end plate; and

[0262] a circumferentially-extending radially-inner wall connected to the outer wall at a position distal to an axially outer end of the first end, the inner wall extending towards the axially outer end of the first end and defining the radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached;

[0263] wherein the outer wall and the inner wall define an annular space between them, the annular space being open adjacent to the axially outer end of the first end.

[0264] Clause 10. The coupling of any one of the preceding clauses, comprising a ridge extending circumferentially around a radially-inner surface of the body, the ridge being configured to inhibit axial movement of molten polymer from a welding region, during welding of the coupling to the spigot.Clause 11. The coupling of any one of clauses 6 to 10, the body comprising a radially-inner O-ring sealing surface for sealing engagement with at least one Ciring.

[0265] Clause 12. The coupling of clause 11, wherein the O-ring sealing surface is axially dimensioned to accept two axially-adjacent O-rings.

[0266] Clause 13. The coupling of clause 12, wherein the O-ring sealing surface is axially dimensioned to accept two axially-adjacent O-rings separated by an O-ring spacer.

[0267] Clause 14. The coupling of any one of clauses 11 to 13, the body comprising a retention feature for retaining a seal-retainer that, in use, retains the at least one O-ring in its installed position.

[0268] Clause 15. The coupling of clause 14, wherein the retention feature comprises at least one radially-extending opening for receiving a radially-extending tooth or pawl of the seal -retainer.

[0269] Clause 16. The coupling of clause 15, wherein the at least one radially-extending opening is a through opening that extends to an outer surface of the body, the through opening being positioned such that, when the coupling is installed onto the spigot at a predetermined orientation, any fluid escaping, in use, past the at least one O-ring can drain through the opening.

[0270] Clause 17. The coupling of any one of clauses 14 to 16, comprising the sealretainer, the seal-retainer being annular and defining:

[0271] a seal-side axial surface for engaging an axially-adjacent one of the at least one O-rings; and

[0272] at least one radially-extending tooth or pawl for engaging the retention feature when the seal-retainer is installed within the body.

[0273] Clause 18. The coupling of clause 17, the body comprising at least one key way configured to guide a corresponding one of the at least one radially-extending tooth or pawl as the seal-retainer is axially inserted into the body.

[0274] Clause 19. The coupling of clause 17 or clause 18, wherein the seal -retainer comprises a radially-outwardly facing shelf extending circumferentially along at least a region adjacent to the tooth or pawl, the coupling and seal -retainer being configured such that the seal-retainer can be demounted from the coupling byusing a tool to engage the shelf so as to radially deform the seal-retainer, thereby to disengage the tooth or pawl from the retention feature.

[0275] Clause 20. The coupling of any one of clauses 17 to 19, wherein the sealretainer is configured to, while a male coupling (preferably, a male quick-connect coupling) is connected to the coupling and in the event of failure of a mechanism on the seal-retainer for preventing axial displacement of the seal-retainer in the direction away from the axially outer end of the first end, axially engage a feature on the male coupling to prevent further axial movement of the seal-retainer in the direction away from the axially outer end of the first end.

[0276] Clause 21. The coupling of any one of clauses 17 to 20, comprising:

[0277] at least one O-ring installed within the body,

[0278] wherein seal-retainer is retained within the body by the retention feature so as to retain the at least on O-ring in its installed position.

[0279] Clause 22. The coupling of any one of clauses 11 to 22, comprising:

[0280] a first locating feature for engaging a distal end of a male coupling coupled within the coupling; and

[0281] a second locating feature for engaging a portion of the male coupling coupled within the coupling, the second locating feature at a position axially spaced from the first locating feature;

[0282] the first locating feature and the second locating feature being configured to inhibit radial movement between a coupled male coupling and the at least one O-ring.

[0283] Clause 23. A cell stack for a redox flow battery, the cell stack comprising:

[0284] a structural end plate;

[0285] the isolator plate of any one of clauses 1 to 5 assembled with the structural end plate such that the spigot extends through an aperture in the structural end plate; and

[0286] the coupling of any one of clauses 6 to 22 connected to the spigot. Clause 24. The cell stack of clause 23, wherein the coupling is permanently connected to the spigot by way of welding, and preferably wherein the structural end plate is permanently located (or sandwiched) between the isolator plate and the coupling.Clause 25. The cell stack of clause 23 or clause 24, the coupling being in accordance with the coupling of clause 21.

[0287] Clause 26. The cell stack of any one of clauses 23 to 25, wherein the internal conduit extends along a longitudinal axis within the body, the coupling comprising:

[0288] a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to the structural end plate; and

[0289] a circumferentially-extending radially-inner wall connected to the outer wall at a position distal to an axially outer end of the first end, the inner wall extending towards the axially-outer end of the first end and defining the internal conduit adjacent to the first end;

[0290] wherein the outer wall and the inner wall define an annular space between them, the annular space being open adjacent to the axially-outer end of the first end; and

[0291] wherein the at least one radially-extending mounting component is fastened to the structural end plate by way of one or more fasteners.

[0292] Clause 27. The cell stack of clause 26, wherein the mounting component comprises at least one flange, the or each flange including at least one aperture, the at least one radially-extending mounting component being fastened to the structural end plate by way of one or more fasteners extending through the one or more apertures.

[0293] Although the invention has been described with reference to a number of specific implementations, the skilled person will appreciate that the invention may be embodied in many other forms.

Claims

CLAIMS1. An isolator plate for assembly between a structural end plate and a stack component in a cell stack for a redox flow battery, the isolator plate comprising:a planar region for isolating, in use, the structural end plate from the stack component; anda spigot extending away from a plane of the planar region, the spigot for extending, in use, through an aperture in the structural end plate, the spigot defining a fluid conduit extending through the planar region, wherein at least a surface of the spigot is formed from a weldable polymer (for example, such that the spigot is configured for permanent attachment to the coupling of any one of claims 7 to 22).

2. The isolator plate of claim 1, wherein an outer surface of the spigot includes a portion that tapers in a direction away from the planar region.

3. The isolator plate of claim 1 or claim 2, wherein at least an outer surface of an end region of the spigot is formed from a weldable polymer, the end region of the spigot distal to the planar region.

4. The isolator plate of any one of the preceding claims, wherein at least an outer surface of the spigot that, in use, extends beyond the aperture on a side of the structural end plate opposite the side on which the planar region of the isolator plate is disposed is formed from a weldable polymer.

5. The isolator plate of any one of the preceding claims, moulded from a polymer.

6. The isolator plate of any one of the preceding claims, wherein the spigot is integral to the isolator plate.

7. A coupling configured for permanent attachment to the spigot of any one of the preceding claims, the coupling defining an internal conduit and comprising:a first end configured for attachment to the spigot, wherein at least a surface of the first end comprises a weldable polymer; anda second end configured to allow releasable connection of a complementary fluid connector.

8. The coupling of claim 7, wherein a portion of a body, intended for connection to the spigot, defines a radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached.

9. The coupling of claim 8, wherein the radially-inner surface comprises a weldable polymer.

10. The coupling of claim 8 or claim 9, wherein the internal conduit extends along a longitudinal axis within the body, the coupling comprising:a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to a structural end plate; anda circumferentially-extending radially-inner wall connected to the outer wall at a position distal to an axially outer end of the first end, the inner wall extending towards the axially outer end of the first end and defining the radially-inner surface that has a profile complementary to that of an outer surface of the spigot to which the coupling is to be attached;wherein the outer wall and the inner wall define an annular space between them, the annular space being open adjacent to the axially outer end of the first end.

11. The coupling of any one of the preceding claims, comprising a ridge extending circumferentially around a radially-inner surface of the body, the ridgebeing configured to inhibit axial movement of molten polymer from a welding region, during welding of the coupling to the spigot.

12. The coupling of any one of claims 7 to 11, the body comprising a radially-inner O-ring sealing surface for sealing engagement with at least one O-ring.

13. The coupling of claim 12, wherein the O-ring sealing surface is axially dimensioned to accept two axially-adjacent O-rings.

14. The coupling of claim 13, wherein the O-ring sealing surface is axially dimensioned to accept two axially-adjacent O-rings separated by an O-ring spacer.

15. The coupling of any one of claims 12 to 14, the body comprising a retention feature for retaining a seal-retainer that, in use, retains the at least one O-ring in its installed position.

16. The coupling of claim 15, wherein the retention feature comprises at least one radially-extending opening for receiving a radially-extending tooth or pawl of the seal-retainer.

17. The coupling of claim 16, wherein the at least one radially-extending opening is a through opening that extends to an outer surface of the body, the through opening being positioned such that, when the coupling is installed onto the spigot at a predetermined orientation, any fluid escaping, in use, past the at least one O-ring can drain through the opening.

18. The coupling of any one of claims 15 to 17, comprising the seal-retainer, the seal-retainer being annular and defining:a seal-side axial surface for engaging an axially-adjacent one of the at least one O-rings; andat least one radially-extending tooth or pawl for engaging the retention feature when the seal-retainer is installed within the body.

19. The coupling of claim 18, the body comprising at least one keyway configured to guide a corresponding one of the at least one radially-extending tooth or pawl as the seal-retainer is axially inserted into the body.

20. The coupling of claim 18 or claim 19, wherein the seal-retainer comprises a radially-outwardly facing shelf extending circumferentially along at least a region adjacent to the tooth or pawl, the coupling and seal-retainer being configured such that the seal-retainer can be demounted from the coupling by using a tool to engage the shelf so as to radially deform the seal-retainer, thereby to disengage the tooth or pawl from the retention feature.

21. The coupling of any one of claims 18 to 20, wherein the seal -retainer is configured to, while a male coupling (preferably, a male quick-connect coupling) is connected to the coupling and in the event of failure of a mechanism on the seal-retainer for preventing axial displacement of the seal-retainer in the direction away from the axially outer end of the first end, axially engage a feature on the male coupling to prevent further axial movement of the seal-retainer in the direction away from the axially outer end of the first end.

22. The coupling of any one of claims 18 to 21, comprising:at least one O-ring installed within the body,wherein seal-retainer is retained within the body by the retention feature so as to retain the at least on O-ring in its installed position.

23. The coupling of any one of claims 12 to 23, comprising:a first locating feature for engaging a distal end of a male coupling coupled within the coupling; anda second locating feature for engaging a portion of the male coupling coupled within the coupling, the second locating feature at a position axially spaced from the first locating feature;the first locating feature and the second locating feature being configured to inhibit radial movement between a coupled male coupling and the at least one O-ring.

24. A cell stack for a redox flow battery, the cell stack comprising:a structural end plate;the isolator plate of any one of claims 1 to 6 assembled with the structural end plate such that the spigot extends through an aperture in the structural end plate; andthe coupling of any one of claims 7 to 23 connected to the spigot.

25. The cell stack of claim 24, wherein the coupling is permanently connected to the spigot by way of welding, and preferably wherein the structural end plate is permanently located (or sandwiched) between the isolator plate and the coupling.

26. The cell stack of claim 24 or claim 25, the coupling being in accordance with the coupling of claim 22.

27. The cell stack of any one of claims 24 to 26, wherein the internal conduit extends along a longitudinal axis within the body, the coupling comprising: a circumferentially-extending radially-outer wall comprising at least one radially-extending mounting component for fastening the coupling to the structural end plate; anda circumferentially-extending radially-inner wall connected to the outer wall at a position distal to an axially outer end of the first end, the inner wall extending towards the axially-outer end of the first end and defining the internal conduit adjacent to the first end;wherein the outer wall and the inner wall define an annular space between them, the annular space being open adjacent to the axially-outer end of the first end; andwherein the at least one radially-extending mounting component is fastened to the structural end plate by way of one or more fasteners.

28. The cell stack of claim 27, wherein the mounting component comprises at least one flange, the or each flange including at least one aperture, the at least one radially-extending mounting component being fastened to the structural end plate by way of one or more fasteners extending through the one or more apertures.

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