Electrochemical cell unit, stack of cell units, fluid guidance insert, method of manufacture of an electrochemical cell unit, method of manufacture of a stack of cell units

Abstract

The invention relates to a cell unit (12) comprising a cell layer (18) and an interconnector plate (28), wherein a periphery (22) of the cell layer (18) is attached to a periphery (30) of the interconnector plate, wherein a central portion (24) of the cell layer and a central portion (32) of the interconnector plate define a fluid volume (34) therebetween, and wherein a fluid guidance insert (52) is disposed in the fluid volumes, said fluid guidance insert defining a fluid channel system for conveying fluid between at least one fluid port of the cell unit and the fluid volume.

Description

[0001] Title: Electrochemical cell unit, stack of cell units, fluid guidance insert, method of manufacture of an electrochemical cell unit, method of manufacture of a stack of cell units

[0002] Specification

[0003] The invention relates to the field of electrochemical cell stacks, in particular, fuel cell stacks and electrolyser cell stacks. More specifically, the invention relates to cell units, to stacks of cell units, to fluid guidance inserts for use in cell units, to methods of manufacture of a cell unit and to methods of manufacture of stacks of cell units.

[0004] Fuel cell units and electrolyser cell units are examples of electrochemical cell units. Fuel cell units are energy conversion devices that allow for conversion of electrochemical fuel to electricity. Electrolyser cell units may be considered fuel cell units running in reverse mode, i.e. using electricity to decompose a compound into its constituent parts, for example water into hydrogen and oxygen. Reversible cell units are capable of operating in both modes.

[0005] Electrochemical cell units often comprise a cell layer having electrochemically active layers and an interconnector plate. The cell layer and the interconnector plate may be sealingly attached to one another and define a fluid volume therebetween. An electrochemical cell unit of this type is disclosed in WO 2020 / 126486 Al, for example. The electrochemically active layers of the cell layer may be configured to allow for conversion of electrochemical fuel to electricity (fuel cells) or for decomposing a compound into its constituent parts using electricity (electrolyser cells).

[0006] The present invention specifically relates to solid oxide cell units (SOCs). Solid oxide cell units (SOCs) typically comprise an electrolyte layer formed from a solid oxide, e.g. from Yttria-stabilised Zirconia (YSZ), Gadolinia-doped Ceria, or Cerium Gadolinium Oxide (CGO). SOCs can be run as solid oxide fuel cell units (SOFC) or as solid oxide electrolyser cell units (SOEC).

[0007] It is an object of the invention to improve the performance of an electrochemical cell unit. According to the invention, there is provided an electrochemical cell unit with the features of claim 1. The cell unit comprises a cell layer having a periphery and a central portion surrounded by the periphery. The central portion of the cell layer comprises electrochemically active layers. The cell unit further comprises an interconnector plate having a periphery and a central portion surrounded by the periphery. The interconnector plate is preferably formed from a metal material. The support plate and the interconnector plate are stacked upon one another (e.g. along a stacking direction). The periphery of the support plate is attached to, preferably sealingly attached to, the periphery of the interconnector plate, e.g. by welding. The central portion of the support plate and the central portion of the interconnector plate define a fluid volume therebetween. That is to say, the central portions of the cell layer and the interconnector plate are spaced apart from each other at least in certain areas to provide said fluid volume. The fluid volume is also referred to as the "internal cell volume" of the cell unit. The peripheries of the cell layer and the interconnector plate may surround the cell volume circumferentially. The cell unit has at least one fluid port that is in fluidic communication with the fluid volume, i.e. only one fluid port or a plurality of fluid ports. At least one fluid guidance insert is disposed in the fluid volume. Thus, the fluid guidance insert is arranged between the central portions of the cell layer and the interconnector plate. The peripheries of the cell layer and the interconnector plate may surround the fluid guidance insert circumferentially. Said fluid guidance insert comprises a plurality of elongate slots formed therein, said elongate slots defining a fluid channel system for conveying fluid between the at least one fluid port and the fluid volume.

[0008] The inventors have found that the proposed fluid guidance insert may improve a fluid flow in the fluid volume. Specifically, the fluid channel system defined by the fluid guidance insert may be configured to convey a fluid, e.g. a fuel, to desired areas of the fluid volume during operation of the cell unit. Furthermore, the fluid guidance insert may transfer compression forces between the cell layer and the interconnector plate. Thus, the fluid guidance insert may increase the mechanical stability of the cell unit in proximity to the fluid port. The use of an insert has the advantage that the attachment between the periphery of the cell layer and the periphery of the interconnector plate is not affected by the presence of the insert. Preferably, the periphery of the interconnector plate is in direct contact with the periphery of the cell layer. That is to say, no additional component is arranged between the peripheries of the interconnector plate and the cell layer. As used herein, the term "insert" relates to a separate unit that is inserted into the fluid volume. Thus, a machined feature of the interconnector plate or the cell layer is not considered to be an insert in the meaning of the invention.

[0009] As used herein, the terms "periphery of the cell layer" and "periphery of the interconnector plate" refer to the parts of the cell layer and the interconnector plate that are attached, preferably sealingly attached, to one another.

[0010] As used herein, the term "central portion of the cell layer" refers to a portion of the cell layer that is surrounded by the periphery of the cell layer.

[0011] As used herein, the term "central portion of the interconnector plate" refers to a portion of the interconnector plate that is surrounded by the periphery of the interconnector plate.

[0012] Preferably, the elongate slots of the fluid guidance insert diverge starting from the fluid port. Regarding the shape of the elongate slots, different configurations are conceivable. In some embodiments, at least one elongate slot has a straight course. In some embodiments, at least one elongate slot has a curved course.

[0013] Preferably, the fluid guidance insert is formed from a metal material, i.e. from metal or metal alloy. Thus, the fluid guidance insert may reliably support the central portions of the cell layer and the interconnector plate.

[0014] Preferably, the cell unit extends in a cell plane that is defined by a first direction and a second direction that is perpendicular to the first direction. The first direction may correspond to a longitudinal extent of the cell unit. The second direction may correspond to a width extent of the cell unit. The peripheries of the cell layer and the interconnector plate are preferably parallel to the cell plane. The above- mentioned stacking direction is preferably perpendicular to the cell plane.

[0015] Preferably, the electrochemical cell unit is a fuel cell unit or an electrolyser cell unit. The cell unit may be a solid oxide cell unit, e.g. solid oxide fuel cell unit or solid oxide electrolyser cell units. The cell unit may be a metal-supported solid oxide cell unit, e.g. a metal-supported solid oxide fuel cell unit or a metal supported solid oxide electrolyser cell unit. In some preferred embodiments, the at least one fluid port comprises at least one fluid inlet port, i.e. only one fluid inlet port or a plurality of fluid inlet ports, for supplying fluid to the fluid volume. The fluid inlet port may be associated with a fluid guidance insert. Thus, said fluid guidance insert may be configured to guide fluid from the fluid inlet port to the fluid volume. In this regard, the fluid guidance insert may help to effectively spread the fluid in the fluid volume, in particular to areas of the fluid volume that might otherwise be undersupplied with fluid. Furthermore, the fluid guidance insert may support the central portions of the cell layer and the interconnector plate in areas adjacent to the fluid inlet port.

[0016] In some preferred embodiments, the at least one fluid port comprises at least one fluid outlet port, i.e. only one fluid outlet port or a plurality of fluid outlet ports, for removing fluid from the fluid volume. The fluid outlet port may be associated with a fluid guidance insert. Thus, said fluid guidance insert may be configured to guide fluid from the fluid volume to the fluid outlet port, e.g. to remove the fluid from the fluid volume through the fluid outlet port to the exterior. In this regard, the fluid guidance insert may help to avoid turbulences or areas with stagnant fluid in the proximity of the fluid outlet port. Furthermore, the fluid guidance insert may support the central portions of the cell layer and the interconnector plate in areas adjacent to the fluid outlet port.

[0017] In some preferred embodiments, the cell unit comprises at least one fluid inlet port and at least one fluid outlet port, wherein the cell unit comprises at least two fluid guidance inserts, and wherein the at least one fluid inlet port and the at least one fluid outlet port are associated with different ones of the at least two fluid guidance inserts.

[0018] In some preferred embodiments, the fluid outlet port is spaced from the fluid inlet port in a first direction. Said first direction may be the above-mentioned first direction defining the cell plane of the cell unit. Preferably, the first direction corresponds to the longitudinal extent of the cell unit. Accordingly, the fluid outlet port may be spaced from the fluid inlet port along the longitudinal extent of the cell unit. Preferably, the electrochemically active layers are disposed between the fluid inlet port and the fluid outlet port. Thus, a fluid flowing from the fluid inlet port to the fluid outlet port may pass the electrochemically active layers. In some preferred embodiments, the cell unit is elongate and comprises a first longitudinal end and a second longitudinal ends. The longitudinal ends are the ends at the short sides of the cell unit.

[0019] Preferably, the at least one fluid inlet port is disposed proximate to the first longitudinal end and the at least one fluid outlet port is disposed proximate to the second longitudinal end. An elongate cell unit with the fluid ports disposed proximate to the longitudinal ends has the advantage that a desired distribution of the fluid within the fluid volume is facilitated. Particularly, an even distribution can be realised by evenly spreading the fluid along the comparatively shorter width extend.

[0020] In some preferred embodiments, the fluid guidance insert is loosely inserted into the fluid volume. That is to say, the fluid guidance insert is not fixedly attached to the cell layer or to the interconnector plate. This has the advantage that the production time of the cell unit may be reduced since time-consuming attachment steps can be avoided.

[0021] In other preferred embodiments, the fluid guidance insert is fixedly attached to the interconnector plate and / or to the cell layer. This has the advantage that the position of the fluid guidance insert relative to the cell layer and to the interconnector plate may be secured. Preferably, the fluid guidance insert is fixedly attached to the interconnector plate and / or to the cell layer by welding.

[0022] In some preferred embodiments, the fluid guidance insert is plate-shaped. This has the advantage that the insert may reliably transfer compression forces between the cell layer and the interconnector plate in a wide area. Preferably, the fluid guidance insert has a flat first surface and an opposed flat second surface. The first surface may be in surface contact with a, preferably flat, surface of the cell layer. The second surface may be in surface contact with a, preferably flat, surface of the interconnector plate.

[0023] In some preferred embodiments, the cell unit further comprises at least one gasket which surrounds a respective one of the at least one fluid port and is positioned on an opposite face of the interconnector plate or the cell layer to the fluid volume. Thus, the at least one gasket is arranged outside the fluid volume. In a cell stack comprising several cell units that are stacked upon one another, the at least one gasket may prevent loss of fluid between the cell unit and a neighbouring cell unit. Preferably, the fluid guidance insert has an extent that exceeds an extent of the gasket (i.e., the fluid guidance insert extends beyond the gasket in a plan view of the cell unit). Thus, in a stack of cell units, the fluid guidance inserts of the cell units may react compression through the cell units. This may improve the sealing effect of the gaskets. In some preferred embodiments, the fluid guidance insert is a single piece, in particular monolithic structure. This may facilitate handling of the fluid guidance insert and avoids displacement of parts of the insert relative to one another.

[0024] In some other embodiments, the fluid guidance insert is formed by a plurality of separate fluid guidance members. This allows, for example, the number and the configuration of the elongate slots (e.g. their width) to be easily adjusted. Specifically, at least one of the elongate slost may be defined by two neighbouring separate fluid guidance members. Where the fluid guidance insert is formed by a plurality of separate fluid guidance members, all fluid guidance members forming the fluid guidance insert are disposed in the fluid volume.

[0025] In some preferred embodiments, the cell layer comprises a support plate, the support plate carrying the electrochemically active layers. In such embodiments, the periphery of the cell layer may be the periphery of the support plate and the central portion of the cell layer may be the central portion of the support plate. A support plate has the advantage that it may resist high compression forces between adjacent cell units in an assembled stack of cell units. Preferably, the support plate is configured flat. Preferably, the electrochemically active layers are coated or deposited on the support plate. Preferably, the support plate is formed from a metal material.

[0026] In some embodiments, the support plate carries the electrochemically active layers on a side that faces away from the cell volume. That is to say, the electrochemically active layers are positioned outside the fluid volume of the cell unit. In some other embodiments, the support plate carries the electrochemically active layers on a side that is facing towards the fluid volume. That is to say, the electrochemically active layers are positioned in the fluid volume.

[0027] In some embodiments, the support plate carries the electrochemically active layers over a porous area, preferably such that a fluid, e.g. fuel, can be transported between the inner fluid volume and a layer of the electrochemically active layers that is closest to the support plate through said porous area.

[0028] In some preferred embodiments, the support plate is tub-shaped. Thus, the support plate may comprise a circumferential wall surrounding a bottom of the tub-shaped support plate. In a tub-shaped support plate, the periphery of the support plate is elevated with respect to the central portion of the plate. In this regard, the periphery of the support plate is also referred to as "flanged perimeter".

[0029] Advantageously, a tub-shaped support plate forms a receiving space for the fluid guidance insert. The circumferential wall of the support plate may restrict movement of the fluid guidance insert in the cell plane defined by the cell unit. Preferably, an outer perimeter of the fluid guidance insert is in direct contact with the circumferential wall of the support plate. In some other embodiments, the support plate is configured flat.

[0030] In some preferred embodiments, the interconnector plate is tub-shaped. Thus, the interconnector plate may comprise a circumferential wall surrounding a bottom of the tub-shaped interconnector plate. In a tub-shaped interconnector plate, the periphery of the interconnector plate is elevated with respect to the central portion of the plate. In this regard, the periphery of the interconnector plate is also referred to as "flanged perimeter". Advantageously, a tub-shaped interconnector plate forms a receiving space for the fluid guidance insert. The circumferential wall of the interconnector plate may restrict movement of the insert in the cell plane defined by the cell unit. Preferably, the outer perimeter of the fluid guidance insert is in direct contact with the circumferential wall of the interconnector plate. In some other embodiments, the interconnector plate is configured flat.

[0031] In some embodiments, the interconnector plate is tub-shaped and the support plate is configured flat.

[0032] In some embodiments, the support plate is configured tub-shaped and the interconnector plate is configured flat. In some embodiments, the interconnector plate and the support plate are configured tub-shaped.

[0033] In some preferred embodiments, the interconnector plate is tub-shaped and a surface of the fluid guidance insert facing the cell layer, e.g. the support plate, is positioned flush with a surface of the periphery of the interconnector plate facing the cell layer, e.g. the support plate. Thus, the surface of the fluid guidance insert and the surface of the periphery of the interconnector plate are positioned in the same plane. This has the advantage that both the surface of the insert and the surface of the periphery of the interconnector plate can establish a direct contact with a flat cell layer, e.g. the support plate.

[0034] In some preferred embodiments, the central portion of the interconnector plate comprises a structured area, said structured area being structured by a plurality of first protrusions extending towards the cell layer and / or by a plurality of second protrusions extending away from the cell layer. The first protrusions of the cell unit may contact the cell layer of that cell unit. Thus, the first protrusions may serve to space the interconnector plate from the cell layer of the same cell unit, thereby providing the fluid volume. The second protrusions of a cell unit may contact the cell layer of a neighbouring cell unit in a stack of cell units. In this way, the protrusions may transfer compression forces through the stack of cell units, while maintaining fluid volumes on either side of the interconnector plates. The structured area may be provided in different shapes in the central portion of the interconnector plate. Preferably, the structured area is rectangular in a plan view of the cell unit.

[0035] The first and second protrusions may have a cross-section having an aspect ratio of less than 10, preferably less than 5, more preferably less than 2. They may have a circular, elliptical, rectangular, or hexagonal (etc.) cross section. In this way, the protrusions may be referred to as dimples, and do not restrict flow of fluid (first protrusions do not restrict flow of fluid in the fluid volume, second protrusions do not restrict flow of fluid outside the fluid volume). Specifically, the first and second protrusions may define a network of interconnected fluid channels therebetween.

[0036] The first and second protrusions may be pressed or formed in the interconnector plate, and so a protrusion on one side of the interconnector plate is a depression on the opposite side of the interconnector plate.

[0037] In some preferred embodiments, the fluid guidance insert is offset from the structured area of the central portion of the interconnector plate. Thus, in a plan view of the cell unit, the structured area and the fluid guidance insert do not overlap. This has the advantage that the fluid guidance insert does not interfere with the direct contact between the cell layer and the first protrusions.

[0038] In some preferred embodiments, the fluid guidance insert comprises at least one arm that extends into a gap between the periphery of the interconnector plate and the structured area. The arm may prevent fluid bypassing the structured area through said gap. Furthermore, the arm may restrict movement of the insert, e.g. in the cell plane. The arm may extend from a main body of the insert. Thus, the arm may be an extension of the fluid guidance insert. In some examples, the structured area may be spaced apart from the periphery in the second direction (which may correspond to the width extent of the cell unit) by the gap. The arm of the insert may extent along the first direction (which may correspond to the longitudinal extend of the cell unit), e.g. from the main body of the insert, and into the gap. Preferably, the interconnector plate is configured tub-shaped and comprises a bottom and a circumferential wall surrounding the bottom, wherein the arm of the insert is engaged against the circumferential wall to restrict movement of the fluid guidance insert. In some embodiments, the fluid guidance insert comprises a first arm and a second arm that are spaced apart from one another along the second direction, wherein the first and second arms extend into a respective gap between the periphery of the interconnector plate and the structured area.

[0039] In some preferred embodiments, the at least one fluid port is provided by a through-hole extending through the central portion of the interconnector plate, through the fluid guidance insert and through the central portion of the cell layer, e.g. the support plate. That is to say, the fluid port is formed by a hole in the interconnector plate, a hole in the fluid guidance insert and a hole in the cell layer, said holes being aligned with each other, e.g. along the stacking direction. The through-hole forming the fluid port may have different shapes. Preferably, the through-hole is circular.

[0040] In some preferred embodiments, the fluid guidance insert is circular and arranged coaxially with a respective one of the at least one fluid ports. Thus, the fluid guidance insert may be associated with only one fluid port. This has the advantage that the structure of the fluid guidance insert and, thus, the manufacture of the fluid guidance insert may be simplified.

[0041] In some preferred embodiments, the at least one fluid port comprises a first fluid port and a second fluid port, wherein a first group of elongate slots of the fluid guidance insert is allocated to the first fluid port for conveying fluid between the first fluid port and the fluid volume, and wherein a second group of elongate slots of the fluid guidance insert is allocated to the second fluid port for conveying fluid between the second fluid port and the fluid volume. Thus, the fluid guidance insert is allocated to two different fluid ports. This reduces the overall number of separate units, which eases manufacturing of the cell unit. Preferably, the first and second fluid ports allocated to the same fluid guidance insert are fluid ports of the same type. That is to say, both fluid ports are fluid inlet ports or both fluid ports are fluid outlet ports.

[0042] In some preferred embodiments, a central elongate slot of the first group of elongate slots and a central elongate slot of the second group of slots merge into one another. As used herein, the term "central elongate slot" of one group of elongate slots is the elongate slot of that group of elongate slots that is located adjacent to the elongate slots of the respective other group of elongate slots. Preferably, the central elongate slot of one group of elongate slots is the elongate slot that is closest to the center of the fluid guidance insert, based on the width extent of the fluid guidance insert. Where the central elongate slots of the first and second group of elongate slots merge into one another, the amount of fluid being conveyed to the fluid volume through a central area of the fluid guidance insert may be increased.

[0043] In some preferred embodiments, the elongate slots each have a proximal end section. As used herein, the term "proximal end section" refers to the end section of an elongate slot that is adjacent to the fluid port.

[0044] In some preferred embodiments, at least one of the elongate slots is closed by a web, wherein a crosssection of a respective one of the at least one fluid port (i.e., the fluid port that is associated with this elongate slot) extends beyond the web to fluidically connect said fluid port with the elongate slot. The web has the advantage that it increases the mechanical stability of the fluid guidance insert. Specifically, the web interconnects portions of the fluid guidance insert that define the respective elongate slot. The configuration of the associated fluid port (the fluid port extends beyond the web, e.g. in a plan view of the cell unit) ensures the fluidic connection between the fluid port and the elongate slot around the web.

[0045] In some preferred embodiments, the proximal end section of at least one of the elongate slots is open. Thus, the proximal end section is not closed by a web or the like. This facilitates the fluidic connection between the associated fluid port and the elongate slot.

[0046] In some preferred embodiments, the proximal end sections extend radially with respect to the associated fluid port. Thus, the proximal end sections diverge from the fluid port. Where the fluid port is a fluid inlet port, this has the advantage that fluid conveyed to the fluid volume may be effectively spread by the fluid guidance insert. Where the fluid port is a fluid outlet port, this has the advantage that turbulences and / or areas with stagnant fluid may be avoided.

[0047] In some preferred embodiments, the elongate slots each have a distal end section. As used herein, the term "distal end section" refers to the end section of an elongate slot that is distant from the fluid port.

[0048] In some preferred embodiments, the diameter of the distal end section of an elongate slot is larger than the diameter of the proximal end section of the same elongate slot. This may help to achieve a more uniform distribution of the fluid in the fluid volume, e.g. along the width extent of the cell unit. In some embodiments, the diameter of the elongate slot increases continuously from the proximal end section to the distal end section. In other embodiments, the diameter of the elongate slot increases stepwise from the proximal end section to the distal end section.

[0049] In some preferred embodiments, the distal end section of at least one of the elongate slots is closed by a web of the fluid guidance insert, wherein the interconnector plate and / or the cell layer has at least one bridge dimple that extends away from the fluid guidance insert and spans said web to form a fluid bypass around said web. The web has the advantage that it increases the mechanical stability of the fluid guidance insert. Specifically, the web interconnects portions of the fluid guidance insert that are defining the respective elongate slot. The bridge dimple ensures the fluidic connection between the fluid volume and the elongate slot around the web. Thus, fluid may be conveyed between the elongate slot and the fluid volume through the bridge dimple around the web. In this way, the bridge dimple may be referred to as "fluid transfer rib". Furthermore, the width and the depth of the bridge dimple may be adapted in order to adjust the flow rate of fluid through the bridge dimple. This may be used to control the fluid distribution in the fluid volume. Preferably, the bridge dimple is formed or pressed. Where the bridge dimple is provided in the interconnector plate, the bridge dimple may be formed or pressed at the same step as the structured area of the interconnector plate (i.e., the first protrusions and / or second protrusions) or the flanged perimeter of the interconnector plate. Alternatively, the bridge dimple may be formed in the interconnector plate or the cell layer by machining or etching. Where the fluid guidance insert comprises several elongate slots each having a distal end section that is closed by a respective web, it is preferred that a respective bridge dimple is associated with each web to form a fluid bypass around the respective web. Furthermore, the bridge dimple may be used to restrict or prevent movement of a gasket associated with the cell unit. Preferably, the cell unit comprises at least one gasket that surrounds a respective one of the at least one fluid port and is positioned on an opposite face of the interconnector plate or cell layer to the fluid volume (i.e., the face is facing away from the fluid volume), wherein the bridge dimple on the interconnector plate or cell layer is a protrusion extending away from the fluid volume to the other face of the interconnector plate or cell layer, and that protrusion acts to restrict or prevent movement of the gasket. Preferably, the protrusion is located directly adjacent to the gasket or reaches into a depression formed in the gasket. In some preferred embodiments, the distal end section of at least one of the elongate slots is open. Thus, the distal end section is not closed by a web or the like. This facilitates the fluidic connection between the fluid volume and the elongate slot.

[0050] In some preferred embodiments, the at least one fluid port comprises two fluid ports, the two fluid ports associated with one fluid guidance insert having elongate slots radiating from each fluid port, at least one elongate slot associated with each fluid port merge into one another at a combined distal end, said combined distal end being closed by a web.

[0051] In some preferred embodiments, the at least one fluid port comprises two fluid ports, the two fluid ports associated with one fluid guidance insert having elongate slots radiating from each fluid port, at least one elongate slot associated with each fluid port merge into one another at a combined distal end, said combined distal end being open.

[0052] In some preferred embodiments, the cell unit has a positioning feature for positioning the fluid guidance insert in the fluid volume. This may restrict or prevent movement of the fluid guidance insert relative to the interconnector plate and the cell layer. Specifically, the positioning feature may restrict or prevent movement of the fluid guidance insert relative to the interconnector plate and the cell layer along the cell plane. This may hold the fluid guidance insert aligned with the associated fluid port. The positioning feature may comprise a first structure of the fluid guidance insert that is in contact with a second structure of the interconnector plate or the cell layer to position the fluid guidance insert in the fluid volume.

[0053] In some preferred embodiments, the positioning feature comprises at least one protrusion on the interconnector plate or on the cell layer, said protrusion extending into a corresponding depression or a corresponding through-hole formed in the fluid guidance insert. As used herein, the term "protrusion on" the interconnector plate or the cell layer includes protrusions that are formed or pressed in the interconnector plate or the cell layer, protrusions that are deposited on the interconnector plate or the cell layer as well as protrusions that are affixed to the interconnector plate or the cell layer. The protrusion may have a circular, elliptical, rectangular, or hexagonal (etc.) cross section.

[0054] In some preferred embodiments, the positioning feature comprises at least one protrusion on the fluid guidance insert, said protrusion extending into a corresponding depression formed in the interconnector plate or in the cell layer, e.g. the support plate. As used herein, the term "protrusion on" the fluid guidance insert includes protrusions that are formed or pressed in the fluid guidance insert, protrusions that are deposited on the fluid guidance insert as well as protrusions that are affixed to the fluid guidance insert. The protrusion may have a circular, elliptical, rectangular, or hexagonal (etc.) cross section. The depression in the interconnector plate or the cell layer, e.g. the support plate, may be formed or pressed.

[0055] In some preferred embodiments, the positioning feature comprises at least one stop surface provided by the interconnector plate or the cell layer, said stop surface configured to cooperate with a downstream of a fluid guidance insert associated with a fluid inlet port or with an upstream end of a fluid guidance insert associated with a fluid outlet port. Where the stop surface cooperates with a downstream end of a fluid guidance insert, the stop surface restricts or prevents movement of the fluid guidance insert in a fluid flow direction. Where the stop surface cooperates with an upstream end of a fluid guidance insert, the stop surface restricts or prevents movement of the fluid guidance insert in a direction opposite to the fluid flow direction.

[0056] In some preferred embodiments, said stop surface is provided by a step or by an indentation of the cell unit that extends into the fluid volume. Thus, a surface of the indentation may form the stop surface and contact the downstream end or the upstream end of a fluid guidance insert. In some embodiments, the cell unit comprises several steps or indentations that are spaced apart from one another, each step or indentation forming a respective stop surface. The step(s) or indentation(s) may be provided in the interconnector plate or the cell layer, e.g. the support plate. Preferably, the step(s) or indentation(s) is / are formed or pressed in the cell unit, e.g. the interconnector plate or the cell layer.

[0057] In some preferred embodiments, the step or the indentation is provided in a circumferential wall of the interconnector plate or the cell layer, e.g. the support plate. Thus, the component comprising the step or the indentation (i.e. the interconnector plate or the cell layer) is configured tub-shaped and comprises a circumferential wall and a bottom surrounded by the circumferential wall. Where the step or indentation is provided in a circumferential wall, the step or indentation is provided in an area where it does not or at most slightly affect the fluid flow in the fluid volume. Specifically, the step or the indentation may be located at the edge of the fluid volume, based on the width extent of the cell unit. According to the invention, there is also provided a stack of electrochemical cell units with the features of claim 40. The stack comprises a plurality of cell units that are stacked upon one another along a stacking direction. The cells units are configured as described above. The stack may further comprise gaskets that are interposed between neighbouring cell units. The stack may be held in compression, e.g., between first and second end plates that are arranged on opposite sides of the stacks. Preferably, a compression force acts on the cell units along the stacking direction. The inserts arranged in the fluid volumes of the cell units may be configured to transfer the compression force through the stack of cell units (together with the interconnector plates, the cell layers and the gaskets).

[0058] According to the invention, there is also provided a fluid guidance insert for use in an electrochemical cell unit, preferably fuel cell unit or electrolyser cell unit, enclosing a fluid volume. The fluid guidance insert comprises a plurality of elongate slots formed therein, said elongate slots defining a fluid channel system for conveying fluid between at least one fluid port of the cell unit and the fluid volume of the cell unit. The elongate slots have a proximal end section and a distal end section.

[0059] Additional preferred features of the fluid guidance insert may be realised as described above.

[0060] Preferably, the fluid guidance insert comprises at least one fluid port. The fluid port may be provided by a hole in the fluid guidance insert. Preferably, each fluid port of the at least one fluid port of the insert is associated with a plurality of elongate slots, and the elongate slots extend radially from said fluid port. An end section of an elongate slot that is adjacent to the fluid port is referred to as "proximal end section". An end section of an elongate slot that distant from the fluid port is referred to as "distal end section". Preferably, the proximal end section of at least one of the elongate slots is closed by a web. The respective elongate slot may radially extend from the web in a distal direction, i.e., away from the fluid port of the fluid guidance insert. Preferably, the proximal end section of at least one of the elongate slots is open. Preferably, the at least one fluid port comprises two fluid ports, the fluid guidance insert having elongate slots radiating from each fluid port, and at least one elongate slot associated with each fluid port merge into one another at a combined distal end that is closed by a web. Preferably, the at least one fluid port comprises two fluid ports, the fluid guidance insert having elongate slots radiating from each fluid port, at least one elongate slot associated with each fluid port merge into one another at a combined distal end that is open. Preferably, the diameter of the distal end section of an elongate slot is larger than the diameter of the proximal end section of the same elongate slot. Preferably, the distal end section of at least one of the elongate slots is closed by a web of the fluid guidance insert. Preferably, the distal end section of at least one of the elongate slots is open. Preferably, the fluid guidance insert further comprises a positioning feature, wherein the positioning feature comprises at least one protrusion on the fluid guidance insert and / or at least one through-hole formed in the fluid guidance insert. Preferably, the fluid guidance is formed from metal.

[0061] According to the invention there is also provided a method of manufacture of an electrochemical cell unit with the features described above. The method comprises providing a cell layer having a periphery and a central portion surrounded by the periphery, the central portion of the cell layer comprising electrochemically active layers. The method further comprises providing an interconnector plate having a periphery and a central portion surrounded by the periphery. The method further comprises providing a fluid guidance insert, said fluid guidance insert comprising a plurality of elongate slots formed therein. The method further comprises overlaying the cell layer and the interconnector plate with the fluid guidance insert positioned therebetween, wherein the central portion of the cell layer and the central portion of the interconnector plate define a fluid volume therebetween, wherein the cell unit has at least one fluid port in fluidic communication with the fluid volume, and wherein said elongate slots of the fluid guidance insert define a fluid channel system for conveying fluid between the at least one fluid port and the fluid volume.

[0062] Additional preferred features, e.g. regarding the configuration of the fluid guidance insert or the interconnector plate, may be realised as described above.

[0063] According to the invention there is also provided a method of manufacture of a stack of cell units with the features described aboce. The method comprises providing a plurality of cell units, wherein each cell unit is configured as described above. The method further comprises overlaying the plurality of cell units upon one another, e.g. along a stacking direction, such that an interconnector plate of a first cell unit faces a cell layer of a second, neighbouring cell unit. Optionally at least one gasket is disposed between neighbouring cell units.

[0064] Additional preferred features, e.g. regarding the configuration of components of the cell units, may be realised as described above.

[0065] According to the invention there is also provided an electrochemical cell unit with the features described above. The cell unit comprises a cell layer comprising electrochemically active layers and an interconnector plate. The cell layer and the interconnector plate overlay one another in an opposed relationship and are spaced from one another to define a fluid volume therebetween. The cell unit has at least one fluid port in fluidic communication with the fluid volume. A fluid guidance insert is disposed in the fluid volume, said fluid guidance insert comprises a plurality of elongate slots formed therein, said elongate slots defining a fluid channel system for conveying fluid between the at least one fluid port and the fluid volume.

[0066] Additional preferred features, e.g. regarding the fluid guidance insert or the interconnector plate, may be realised as described above. The cell unit may be manufactured according to the above-described method of manufacture of a cell unit.

[0067] Further embodiments are derivable from the following description and the drawings:

[0068] Figure 1 shows a perspective view of a stack of electrochemical cell units according to an embodiment;

[0069] Figure 2 shows an exploded perspective view of a cell unit of the stack of Figure 1;

[0070] Figure 3 shows another exploded perspective view of the cell unit;

[0071] Figure 4A shows a bottom view of the cell unit;

[0072] Figure 4B shows a cross-sectional view of the cell unit along the sectional plane A-A' shown in

[0073] Figure 4A;

[0074] Figure 5A shows another bottom view of the cell unit;

[0075] Figure 5B shows a cross-sectional view of the cell unit along the sectional plane Z-Z' shown in

[0076] Figure 5A;

[0077] Figure 6 shows different embodiments of a fluid guidance insert;

[0078] Figure 7 shows an exploded perspective view of a detail of a cell unit according to another embodiment;

[0079] Figure 8 shows a plan view of a detail of a cell unit according to another embodiment;

[0080] Figure 9 shows an exploded perspective view of a cell unit according to another embodiment;

[0081] Figure 10 shows a plan view of an interconnector plate of the cell unit shown in Figure 9;

[0082] Figure 11 shows a plan view of an interconnector plate according to another embodiment;

[0083] Figure 12 shows another embodiment of a fluid guidance insert;

[0084] Figure 13 shows another embodiment of a fluid guidance insert; and

[0085] Figure 14 shows another embodiment of a fluid guidance insert. Referring to Figure 1, there is shown an exemplary configuration of a stack 10 of cell units 12. The stack 10 comprises a plurality of electrochemical cell units 12 that are stacked upon one another along a stacking direction 14. Neighbouring cell units 12 are in direct contact with one another, said direct contact providing an electrical connection between the cell units 12.

[0086] With additional reference to Figures 2-5, the configuration of a cell unit 12 of the cell units 12 will be explained in more detail. The cell unit 12 extends in a cell plane that is perpendicular to the stacking direction 14. The cell plane is defined by a first direction 15 (see Figure 4A) and a second direction 16 that is perpendicular to the first direction 15. The first direction 15 corresponds to the length extent of the cell unit 12. The second direction 16 corresponds to the width extent of the cell unit 12.

[0087] The cell unit 12 comprises a cell layer 18 comprising electrochemically active layers 20. The cell layer 18 comprises a periphery 22 and a central portion 24 surrounded by the periphery. In this example, the periphery 22 and the central portion 24 are formed by a support plate 26 of the cell layer 18. The electrochemically active layers 20 are carried by the central portion 24 of the support plate 26.

[0088] The cell unit 12 further comprises an interconnector plate 28 having a periphery 30 and a central portion 32 surrounded by the periphery 30.

[0089] In the assembled cell unit 12 (see Figures 1, 4B and 5B), the cell layer 18 and the interconnector plate 28 are stacked upon one another along the stacking direction 14. The periphery 22 of the cell layer 18 is sealingly attached to the periphery 30 of the interconnector plate 28 (in this case, directly attached), preferably by welding. The central portion 24 of the cell layer 18 and the central portion 32 of the interconnector plate 28 define or enclose a fluid volume 34 therebetween. The fluid volume 34 is an internal cell volume of the cell unit 12.

[0090] In this example, the electrochemically active layers 20 are arranged on a side of the central portion 24 of the cell layer 18 that faces away from the fluid volume 34 of the assembled cell unit 12.

[0091] The electrochemically active layers 20 may be carried by a porous area 36 (see Figure 3) of the central portion 24 of the cell layer 18 such that during operation a fluid, e.g. a fuel, may exit the fluid volume 34 through pores formed in the porous area 36 and reach to a layer of the electrochemically active layers 20 that is closest to the support plate 26.

[0092] In this example, the central portion 32 of the interconnector plate 28 comprises a structured area 38. The structured area 38 comprises a plurality of first protrusions 40a protruding towards the cell layer 18 and a plurality of second protrusions 40b protruding away from the cell layer 18, i.e. in the opposite direction. A reduced number of protrusions 40a, 40b are depicted in Figures 2-5 for clarity of the Figures. It will be understood that there will typically be many more protrusions 40a, 40b than those depicted. Further, the protrusions 40a, 40b are typically pressed or formed in the sheet forming the interconnector plate 28. For example, a second protrusion 40b on one side of the interconnector plate 28, facing away from the cell layer 18, typically forms a depression on the other side of the interconnector plate 28, facing towards the cell layer 18 (and similarly for first protrusions 40a).

[0093] In the stack 10 of cell units 12, the first protrusions 40a of a given cell unit 12 contact the cell layer 18 of that cell unit 12, and the second protrusions 40b of that cell unit 12 contact the cell layer 20 of the adjacent / neighboring cell unit 12. In this way, the protrusions 40a, 40b transfer compression forces through the stack 10, while maintaining the fluid volumes on either side of the interconnector plate 28.

[0094] The first and second protrusions 40a, 40b typically have a circular cross section. In this way, the protrusions 40a, 40b may be referred to as dimples, and do not restrict flow of fluid (first protrusions 40a do not restrict flow of fluid in the cell volume 34, second protrusions 40b do not restrict flow of fluid outside the cell volume 34). The first and second protrusions 40a, 40b may define a network of interconnected fluid channels on each side of the interconnector plate 28.

[0095] The protrusions 40a, 40b are exemplary. Other means for maintaining the spacing between interconnector plate 28 and cell layer 18 (to provide the fluid volumes therebetween) may be used in combination with the interconnector plate 18 described herein. For example, ribs which may also act to direct fluid flow.

[0096] In this example, the interconnector plate 28 is configured tub-shaped. Thus, the interconnector plate 28 comprises a bottom 102 and a circumferential wall 104 between the bottom 102 and the periphery 30. In this example, the bottom 102 is configured flat and extends parallel to the cell plane. The circumferential wall 104 is angled with respect to the cell plane and with respect to the stacking direction 14.

[0097] The cell unit 12 further comprises at least one fluid port. In this example, the cell unit 12 comprises one fluid inlet port 42 and one fluid outlet port 44. The fluid inlet port 42 and the fluid outlet port 44 are formed by a respective through-hole 106 or 108 that extends through the cell unit 12. In the assembled stack 10 of cell units 12, the fluid inlet ports 42 and the fluid outlet ports 44 of the cell units 12 are aligned with each other along the stacking direction 14, thus forming a fluid inlet manifold or a fluid outlet manifold, respectively. During operation, a fluid, e.g. a fuel, may be supplied to the fluid volume 34 through the fluid inlet port 42.

[0098] The fluid inlet port 42 is located at a first longitudinal end 46 of the cell unit 12. The fluid outlet port 44 is located at a second longitudfinal end 48 of the cell unit 12. The porous area 36 and the structured area 38 are located between the fluid inlet port 42 and the fluid outlet port 44. Thus, a fluid, e.g. a fuel, that flows from the fluid inlet port 42 to the fluid outlet port 44 may pass through the structured area 38 and reach to the electrochemically active layers 20 carried by the porous area 36.

[0099] Each fluid port is associated with a respective gasket 50. In this example, the gaskets 50 are positioned on a face of the interconnector plate 28 that faces away from the fluid volume 34. One of the gaskets 50 is associated with the fluid inlet port 42 and surrounds the fluid inlet port 42. The other one of the gaskets 50 is associated with the fluid outlet port 44 and surrounds the fluid outlet port 44. In the assembled stack 10 of cell units 12, the gaskets 50 contribute to forming the fluid inlet manifold and the fluid outlet manifold and prevent loss of fluid between adjacent / neighbouring cell units 12.

[0100] The cell unit 12 further comprises at least one fluid guidance insert 52 that is disposed in the fluid volume 34 and associated with at least one fluid port. In this example, the cell unit 12 comprises two fluid guidance inserts 52. The fluid guidance inserts 52 each comprise a plurality of elongate slots 54 formed therein, said elongate slots 54 defining a fluid channel system for conveying fluid between the associated fluid port and the cell volume 34.

[0101] In the following, the configuration of the fluid guidance inserts 52 provided in the cell unit 12 of Figures 2-5 will be explained with additional reference to Figure 6. This Figure shows different embodiments of the fluid guidance insert 52, wherein the fluid guidance insert 52 shown on the left side in the upper row corresponds to the fluid guidance inserts 52 provided in the cell unit 12 shown in Figures 2-5. The other embodiments of the fluid guidance insert 52 shown in Figure 6 will be described later.

[0102] The fluid guidance insert 52 (the one provided in the cell unit 12 of Figures 2-5 and shown on the left side in the upper row of Figure 6) comprises a hole 56 formed therein. The elongate slots 54 radiate from the hole 56. In this example, three elongate slots 54 are provided in the insert 52.

[0103] The elongate slots 54 each comprise a proximal end section 58 and a distal end section 60. The proximal end sections 58 are adjacent to the hole 56. In this example, the proximal end sections 58 extend radially with respect to the hole 56. Thus, an imaginary extension of the proximal end sections 58 extends through the center of the hole 56. The distal end sections 60 are distant from the hole 56.

[0104] In the cell unit 12 shown in Figures 2-5, one fluid guidance insert 52 is associated with the fluid inlet port 42. This fluid guidance insert 52 is arranged such that the hole 56 contributes to forming the through- hole 106, i.e. the fluid inlet port 42. The fluid guidance insert 52 associated with the fluid inlet port 42 is configured to convey a fluid from the fluid inlet port 42 to the fluid volume 34. Specifically, a fluid may reach from the fluid inlet port 42 through the elongate slots 54 of the insert 52 to the fluid volume 34. The fluid guidance insert 52 may spread the fluid along the second direction 16. Thus, the fluid guidance insert 52 associated with the fluid inlet port 52 may support a more uniform distribution of the fluid in the fluid volume 34 along the second direction 16, i.e. the width extent of the cell unit 12.

[0105] In the cell unit 12 shown in Figures 2-5, one fluid guidance insert 52 is associated with the fluid outlet port 44. This fluid guidance insert 52 is arranged such that the hole 56 contributes to forming the through-hole 108, i.e. the fluid outlet port 44. The fluid guidance insert 52 associated with the fluid outlet port 44 is configured to convey a fluid from the fluid volume 34 to the fluid outlet port 44. Specifically, a fluid may reach from the fluid volume 34 through the elongate slots 54 of the insert 52 to the fluid outlet port 44. The fluid guidance insert 52 associated with the fluid outlet port 44 may reduce or prevent areas with stagnant fluid in the fluid volume 34 and reduce turbulences.

[0106] The fluid guidance insert 52 is configured flat. In the assembled cell unit 12 (see Figures 4B and 5B), a first surface 64 of the fluid guidance insert 52 is in direct contact with an opposed surface of the cell layer 18, i.e. the support plate 26. A second surface 66 of the fluid guidance insert 52 is in direct contact with an opposed surface of the interconnector plate 28. Thus, the fluid guidance inserts 52 may transfer compression forces between the cell layer 18 and the interconnector plate 28. This may increase the mechanical stability of the cell unit 12. Specifically, the fluid guidance inserts 52 may prevent a deformation of the cell layer 18 and the interconnector plate 28.

[0107] In this example, the proximal end sections 58 of the elongate slots 54 are open. That is to say, the proximal end sections 58 open into the hole 56.

[0108] In this example, the distal end section 60 of the central elongate slot 54, i.e. the elongate slot that is surrounded by two outer elongate slots 54 is open. Thus, the distal end section 60 of that elongate slot 54 opens into the fluid volume 34. The distal end sections 60 of the outer elongate slots 54 are closed by a respective web 62. This increases the mechanical stability of the fluid guidance insert 52. The interconnector plate 28 comprises several bridge dimples 68 that extend away from the fluid guidance insert 52 and that span a respective one of the webs 62 to form a fluid bypass around that web 62. Thus, the bridge dimples 68 flu idically connect the respective elongate slot 54 with the fluid volume 34 around the respective web 62. In this example, each one of the outer elongate slots 54 is associated with a respective bridge dimple 68. Alternatively, several webs 62 may be associated with a common bridge dimple 68 or several bridge dimples 68 may be associated with a common web 62.

[0109] In this example, the bridge dimples 68 are formed or pressed in the interconnector plate 28. Preferably, the bridge dimples 68 are formed or pressed at the same step as the structured area 38 of the interconnector plate 28 (i.e., the first and second protrusions 40a, 40b) or the flanged perimeter of the tub-shaped interconnector plate 28.

[0110] On the side of the interconnector plate 28 that is facing away from the fluid volume 34, the bridge dimples 68 form protrusions 70 that are extending away from the fluid volume 34. As can be seen in Figures 5A and 5B, the gaskets 50 are positioned directly adjacent to the protrusions 70. The outer perimeter of the gaskets 50 is in direct contact with the protrusions 70. Thus, the protrusions 70 restrict movement of the gaskets 50, particularly along the first direction 15.

[0111] In this example, the cell unit 12 has a respective positioning feature 72 for positioning the fluid guidance inserts 52 in the fluid volume 34. The positioning feature 72 comprises protrusions 74 on the interconnector plate 28 that extend towards the cell layer 18. In this example, the protrusions 74 are formed or pressed in the interconnector plate 28. The protrusions 74 extend into a corresponding through-hole 76 formed in the fluid guidance inserts 52. This prevents movement of the fluid guidance inserts 52 relative to the interconnector plate 28. The through-holes 76 are provided in the fluid guidance insert 52 in addition to the hole 56.

[0112] In an alternative example, instead of a bridge dimple 68 corresponding to each slot 54, a single bridge depression may be provided. This may be termed a 'trough', or fluid transfer rib. This fluid transfer rib, or trough, spans the web portion 62 of the fluid guidance insert 52 thus providing a bypass around the web 62 for multiple slots 54. Dimples or other supporting structures may be provided in or around the single depression to support the web portion 62 of the fluid guidance insert 52. Corresponding downward dimples or similar structures may be provided to transfer the force supporting the fluid guidance insert 52 to the cell unit below.

[0113] It should be appreciated that a combination of the above examples may be provided, for example, a fluid transfer rib which spans multiple slots 54 and bridge dimples 68 that correspond to a single slot 54.

[0114] In the following, the configuration of the remaining fluid guidance inserts 52 shown in Figure 6 will be explained.

[0115] The right fluid guidance insert 52 in the upper row differs from the fluid guidance insert 52 shown in Figures 2-5 in that it does not comprise the through-holes 76. Movement of this fluid guidance insert 52 can be prevented by fixedly attaching the insert 52 to the cell layer 18 or to the interconnector plate 28, for example. Preferably, the fluid guidance insert 52 is welded to the cell layer 18 and / or to the interconnector plate 28.

[0116] The left fluid guidance insert 52 in the lower row differs from the fluid guidance insert 52 shown in Figures 2-5 in that the distal end sections 60 of all elongate slots 54 are closed by a respective web 62.

[0117] The right fluid guidance insert 52 in the lower row differs from the fluid guidance insert 52 shown in Figures 2-5 in that the distal end sections 60 of all elongate slots 54 are closed by a respective web 62. Furthermore, the fluid guidance insert 52 does not comprise the through-holes 76.

[0118] Figure 7 shows a perspective exploded view of a detail of a cell unit 12 according to another embodiment. In the embodiment shown in Figure 7, the fluid guidance insert 52 is configured circular. The fluid guidance insert 52 comprises elongate slots 54 along its entire circumference. The distal end sections 60 of the elongate slots 54 are closed by a respective web 62. Elongate slots 54 of a first group are associated with a respective bridge dimple 68 provided in the interconnector plate 28. The bridge dimples 68 form a fluid bypass around the webs 62 closing the distal end sections 60 of the elongate slots 54 of the first group. Elongate slots 54 of a second group are devoid of an associated bridge dimple 68. Specifically, those elongate slots 54 that are directed towards an edge of the cell unit 12 adjacent to the fluid guidance insert 52 are elongate slots 54 of the second group. Thus, the elongate slots 54 of the second group are not bypassed and do not convey fluid between the associated fluid port and the fluid volume during operation.

[0119] Figure 8 shows a plan view of a cell unit 12 according to another embodiment (the cell layer is not shown in Figure 8). In the embodiment shown in Figure 8, the fluid guidance insert 52 is configured circular. In this example, the fluid guidance insert 52 comprises elongate slots 54 along its entire circumference. The proximal end sections 58 of the elongate slots 54 are closed by a respective web 62, in this example. This increases the mechanical stability of the fluid guidance insert 52. The cross-section of the fluid port (in this example a fluid inlet port 42) associated with the fluid guidance insert 52 extends beyond the webs 62 to fluidically connect the fluid port 42 with the elongate slots 54. Thus, in the plan view of Figure 8, there are radial gaps 78 between the webs 62 and the outer contour 80 of the fluid inlet port 42. The webs 62 are positioned radially within the associated fluid port, based on an axis that runs through the center of the fluid port and is perpendicular to the cell plane.

[0120] Figure 9 shows a perspective exploded view of a cell unit 12 according to another embodiment. Figure 10 shows a plan view of the interconnector plate 28 of the cell unit 12. The cell unit 12 of Figure 9 has a first fluid inlet port 42a and a second fluid inlet port 42b as well as a first fluid outlet port 44a and a second fluid outlet port 44b. The structured area 38 is located between the fluid inlet ports 42 and the fluid outlet ports 44.

[0121] Figure 12 shows a plan view of a fluid guidance insert 52 that is suitable for use in the cell unit 12 shown in Figures 9 and 10. The location of two such inserts 52 is indicated in Figure 10 with dashed lines. The fluid guidance insert 52 shown in Figure 11 comprises a first hole 56a and a second hole 56b. A first group of 82 of elongate slots 54 is radiating from the first hole 56a. A second group 84 of elongate slots 54 is radiating from the second hole 56b. In the embodiment shown in Figure 11, the distal end sections 60 of the elongate slots 54 are closed by a respective web 62. The interconnector plate 28 shown in Figure 10 comprises bridge dimples to bypass the webs 62. However, the bridge dimples are not shown in Figure 10 for the sake of simplicity.

[0122] Figure 11 shows an interconnector plate 28 according to another embodiment. The fluid guidance insert 52 shown in Figure 12 is also compatible with this interconnector plate 28 and shown in Figure 11 with dashed lines. The interconnector plate 28 differs from the interconnector plate 28 shown in Figure 10 in that it comprises a positioning feature 72 having stop surfaces 86 that that are configured to cooperate with a downstream end 88 of the fluid guidance insert 52 associated with the fluid inlet ports 42 or with an upstream end 90 of the fluid guidance insert 52 associated with the fluid outlet ports 44.

[0123] In this example, the stop surfaces 86 are provided by a respective step 92 that is formed in the interconnector plate 28 and extends into the fluid volume 34 (i.e. towards the center of the interconnector plate 28). Specifically, the steps 92 are formed in a circumferential wall of the interconnector plate 28 (not visible in Figure 11). The steps 92 are provided along the length extent of the cell unit 12, e.g., between the fluid inlet ports 42 and the structured area 38 or between the fluid outlet ports 44 and the structured area 38.

[0124] Figure 13 shows a fluid guidance insert 52 according to another embodiment. This fluid guidance insert 52 differs from the fluid guidance insert 52 shown in Figure 12 in that the central elongate slot 54a of the first group 82 merges into the central elongate slot 54b of the second group 84. The central elongate slots 54a are the elongate slots 54 that are adjacent to the respective other group of elongate slots 54. Thus, the central elongate slots 54a have a combined distal end 94. In this example, the combined distal end 94 is open. In another example, the combined distal end 94 is closed by a web.

[0125] Figure 14 shows a fluid guidance insert 52 according to another embodiment. This fluid guidance insert 52 differs from the fluid guidance insert 52 shown in Figure 13 in that it has a respective arm 98 at its side ends. As can be seen in Figure 10, the structured area 38 is spaced apart from the periphery 30 of the interconnector plate 28 along the second direction 16 by a respective gap 100. During operation, a fluid may bypass the structured area 38 through the gaps 100. The arms 98 are configured to extend into the gaps 100. Thus, when arranged in the fluid volume 34 of a cell unit 12 comprising the interconnector plate 28 of Figure 10, the arms 98 extend along the first direction 15 and into the gaps 100. Thus, the arms 98 may prevent that fluid bypasses the structured area 38.

Claims

Claims1. An electrochemical cell unit (12), preferably a fuel cell unit or an electrolyser cell unit, comprising: a cell layer (18) having a periphery (22) and a central portion (24) surrounded by the periphery (22), the central portion (24) of the cell layer (18) comprising electrochemically active layers (20), and an interconnector plate (28) having a periphery (30) and a central portion (32) surrounded by the periphery (30), wherein: the cell layer (18) and the interconnector plate (28) are stacked upon one another, the periphery (22) of the cell layer (18) is attached to the periphery (30) of the interconnector plate (28), the central portion (24) of the cell layer (18) and the central portion (32) of the interconnector plate (28) define a fluid volume (34) therebetween, the cell unit (12) has at least one fluid port (42, 44) in fluidic communication with the fluid volume (34), and a fluid guidance insert (52) is disposed in the fluid volume (34), said fluid guidance insert (52) comprising a plurality of elongate slots (54) formed therein, said elongate slots (54) defining a fluid channel system for conveying fluid between the at least one fluid port (42, 44) and the fluid volume (34).

2. The cell unit (12) according to claim 1, wherein the at least one fluid port (42, 44) comprises at least one fluid inlet port (42) for supplying fluid to the fluid volume (34).

3. The cell unit (12) according to claim 1 or 2, wherein the at least one fluid port (42, 44) comprises at least one fluid outlet port (44) for removing fluid from the fluid volume (34).

4. The cell unit according to claim 3, wherein the cell unit (12) comprises at least one fluid inlet port (42) and at least one fluid outlet port (44), the cell unit (12) comprises at least two fluid guidance inserts (52), and the at least one fluid inlet port (42) and the at least one fluid outlet port (44) are associated with different ones of the at least two fluid guidance inserts (52).

5. The cell unit (12) according to the preceding claim, wherein said fluid outlet port (44) is spaced from the fluid inlet port (42) in a first direction (15).

6. The cell unit (12) according to claim 4 or 5, wherein the cell unit (12) is elongate and comprises a first longitudinal end (46) and a second longitudinal end (48), wherein the at least one fluid inlet port (42) is disposed proximate to the first longitudinal end (46), and wherein the at least one fluid outlet port (44) is disposed proximate to the second longitudinal end (48).

7. The cell unit (12) according to any one of the preceding claims, wherein the fluid guidance insert (52) is loosely inserted into the fluid volume (34).

8. The cell unit (12) according to any one of claims 1 to 6, wherein the fluid guidance insert (52) is fixedly attached to the interconnector plate (28) and / or to the cell layer (18).

9. The cell unit (12) according to any one of the preceding claims, wherein the fluid guidance insert (52) is plate-shaped.

10. The cell unit (12) according to the preceding claim, wherein the cell unit (12) further comprises at least one gasket (50) which surrounds a respective one of the at least one fluid port (42, 44) and is positioned on an opposite face of the interconnector plate (28) or cell layer (18) to the fluid volume (34), and wherein the fluid guidance insert (52) has an extent that exceeds an extent of the gasket (50).

11. The cell unit (12) according to any one of the preceding claims, wherein the fluid guidance insert (52) is a monolithic structure.

12. The cell unit (12) according to any one of claims 1 to 10, wherein the fluid guidance insert (52) is formed by a plurality of separate fluid guidance members.

13. The cell unit (12) according to any one of the preceding claims, wherein the cell layer (18) comprises a support plate (26) carrying the electrochemically active layers (20).

14. The cell unit (12) according to the preceding claim, wherein one or both the support plate (26) and the interconnector plate (28) is tub-shaped.

15. The cell unit (12) according to the preceding claim, wherein a surface (64) of the fluid guidance insert (52) facing the cell layer (18) is flush with a surface of the periphery (30) of the interconnector plate (28) facing the cell layer (18).

16. The cell unit (12) according to any one of the preceding claims, wherein the central portion (32) of the interconnector plate (28) comprises a structured area (38), said structured area (38) being structured by a plurality of first protrusions (40a) extending towards the cell layer (18) and / or by a plurality of second protrusions (40b) extending away from the cell layer (18).

17. The cell unit (12) according to the preceding claim, wherein the fluid guidance insert (52) is offset from the structured area (38) of the central portion (32) of the interconnector plate (28).

18. The cell unit (12) according to any one of claims 16 and 17, wherein fluid guidance insert (52) comprises at least one arm (98) that extends into a gap (100) between the periphery (30) of the interconnector plate (28) and the structured area (38).

19. The cell unit (12) according to any one of the preceding claims, wherein the at least one fluid port (42, 44) is provided by a through-hole (106, 108) extending through the central portion (32) of the interconnector plate (28), the fluid guidance insert (52) and the central portion (24) of the cell layer (18).

20. The cell unit (12) according to any one of the preceding claims, wherein the fluid guidance insert (52) is circular and arranged coaxially with a respective one of the at least one fluid ports (42, 44).

21. The cell unit (12) according to any one of claims 1 to 19, wherein the at least one fluid port (42, 44) comprises a first fluid port (42a, 44a) and a second fluid port (42b, 44b), wherein a first group (82) of elongate slots (54) of the fluid guidance insert (52) is allocated to the first fluid port (42a, 44a) for conveying fluid between the first fluid port (42a, 44a) and the fluid volume (34), and wherein a second group (84) of elongate slots (54) of the fluid guidance insert (52) is allocated to the second fluid port (42b, 44b) for conveying fluid between the second fluid port (42b, 44b) and the fluid volume (34).

22. The cell unit (12) according to the preceding claim, wherein a central elongate slot (54a) of the first group (82) of elongate slots (54) and a central elongate slot (54a) of the second group (84) of elongate slots (54) merge into one another.

23. The cell unit (12) according to any one of the preceding claims, wherein the elongate slots (54) each have a proximal section (58), wherein the proximal end section (58) of at least one of the elongate slots (54) is closed by a web (62), a cross-section of a respective one of the at least one fluid port (42, 44) extending beyond the web (62) to fl uidically connect said fluid port (42, 44) with the elongate slot (54).

24. The cell unit (12) according to any one of the preceding claims, wherein the elongate slots (54) each have a proximal section (58), wherein the proximal end section (58) of at least one of the elongate slots (54) is open.

25. The cell unit (12) according to any one of claims 23 and 24, wherein the proximal end sections (58) extend radially with respect to the associated fluid port (42, 44).

26. The cell unit (12) according to any one of the preceding claims, wherein the elongate slots (54) each have a distal end section (60), wherein the diameter of the distal end section (60) of an elongate slot (54) is larger than the diameter of the proximal end section (58) of the same elongate slot (54).

27. The cell unit (12) according to any one of the preceding claims, wherein the elongate slots (54) each have a distal end section (60), wherein the distal end section (60) of at least one of the elongate slots (54) is closed by a web (62) of the fluid guidance insert (52), and wherein the interconnector plate (28) and / or the cell layer (18) has at least one bridge dimple (68) that extends away from the fluid guidance insert (52) and spans said web (62) to form a fluid bypass around the web (62).

28. The cell unit (12) according to any one of claims 26 and 27, wherein the distal end section (60) of at least one of the elongate slots (54) is open.

29. The cell unit (12) according to any one of claims 26 to 28, wherein the at least one fluid port (42, 44) comprises two fluid ports (42a, 42b), the two fluid ports (42a, 42b) associated with one fluid guidance insert (52) having elongate slots (54) radiating from each fluid port (42a, 42b), at leastone elongate slot (54) associated with each fluid port (42a, 42b) merge into one another at a combined distal end (94) that is closed by a web (62).

30. The cell unit (12) according to any one of claims 26 to 28, wherein the at least one fluid port (42, 44) comprises two fluid ports (42a, 42b), the two fluid ports (42a, 42b) associated with one fluid guidance insert (52) having elongate slots (54) radiating from each fluid port (42a, 42b), at least one elongate slot (54) associated with each fluid port (42a, 42b) merge into one another at a combined distal end (94) that is open.

31. The cell unit (12) according to any one of the preceding claims, wherein the cell unit (12) has a positioning feature (72) for positioning the fluid guidance insert (52) in the fluid volume (34).

32. The cell unit (12) according to the preceding claim, wherein the positioning feature (72) comprises at least one protrusion (74) on the interconnector plate (28) or on the cell layer (18), said protrusion (74) extending into a corresponding depression or a corresponding through-hole (76) formed in the fluid guidance insert (52).

33. The cell unit (12) according to any one of claims 31 and 32, wherein the positioning feature (72) comprises at least one protrusion on the fluid guidance insert (52), said protrusion extending into a corresponding depression formed in the interconnector plate (28) or in the cell layer (18).

34. The cell unit (12) according to any one of claims 31 to 33, wherein the positioning feature (72) comprises at least one stop surface (86) provided by the interconnector plate (28) or the cell layer (18), said stop surface (86) configured to cooperate with a downstream end (88) of a fluid guidance insert (52) associated with a fluid inlet port (42) or with an upstream end (90) of a fluid guidance insert (52) associated with a fluid outlet port (44).

35. The cell unit (12) according to the preceding claim, wherein said stop surface (84) is provided by a step (92) or an indentation of the cell unit (12) that extends into the fluid volume (34).

36. The cell unit (12) according to the preceding claim, wherein the step (92) or the indentation is provided in a circumferential wall (104) of the interconnector plate (28) or the cell layer (18).

37. A stack (10) of cell units (12), comprising: a plurality of cell units (12) stacked upon one another along a stacking direction (14), said cell units (12) being configured according to any one of the preceding claims.

38. A fluid guidance insert (52) for use in an electrochemical cell unit (12) enclosing a fluid volume (34), the fluid guidance insert (52) comprising a plurality of elongate slots (54) formed therein, said elongate slots (54) defining a fluid channel system for conveying fluid between at least one fluid port (42, 44) and the fluid volume (34), said elongate slots (54) having a proximal end section (58) and a distal end section (60).

39. The fluid guidance insert (52) according to the preceding claim, wherein the fluid guidance insert (52) comprises at least one fluid port.

40. The fluid guidance insert (52) of claim 39, wherein each fluid port of the at least one fluid port is provided with a plurality of elongate slots (54), and the elongate slots (54) extend radially from said fluid port.

41. The fluid guidance insert (52) according to any one of claims 39 and 40, wherein the proximal end section (58) of at least one of the elongate slots (54) is closed by a web (62).

42. The fluid guidance insert (52) according to any one of claims 39 to 41, wherein the proximal end section (58) of at least one of the elongate slots (54) is open.

43. The fluid guidance insert (52) according to any one of claims 39 to 42, wherein the at least one fluid port comprises two fluid ports, the fluid guidance insert (52) having elongate slots (54) radiating from each fluid port, and at least one elongate slot (54) associated with each fluid port merge into one another at a combined distal end (94) that is closed by a web (62).

44. The fluid guidance insert (52) according to any one of claims 39 to 42, wherein the at least one fluid port comprises two fluid ports, the fluid guidance insert (52) having elongate slots (54) radiating from each fluid port, at least one elongate slot (54) associated with each fluid port merge into one another at a combined distal end (94) that is open.

45. The fluid guidance insert (52) according to any one of claims 38 to 44, wherein the diameter of the distal end section (60) of an elongate slot (54) is larger than the diameter of the proximal end section (58) of the same elongate slot (54).

46. The fluid guidance insert (52) according to any one of claims 38 to 45, wherein the distal end section (60) of at least one of the elongate slots (54) is closed by a web (62) of the fluid guidance insert (52).

47. The fluid guidance insert (52) according to any one of claims 38 to 46, wherein the distal end section (60) of at least one of the elongate slots (54) is open.

48. The fluid guidance insert (52) according to any one of claims 38 to 47, wherein the fluid guidance insert (52) further comprises a positioning feature (72), wherein the positioning feature (72) comprises at least one protrusion on the fluid guidance insert (52) and / or at least one through-hole (76) formed in the fluid guidance insert (52).

49. The fluid guidance insert (52) according to any one of claims 38 to 48, wherein the fluid guidance insert (52) is formed from metal.

50. The fluid guidance insert (52) according to any one of claims 38 to 49 for use in the cell unit (12) according to any one of claims 1 to 36 or the stack (10) of cell units (12) according to claim 37.

51. A method of manufacture of an electrochemical cell unit (12), comprising: providing a cell layer (18) having a periphery (22) and a central portion (24) surrounded by the periphery (22), the central portion (24) of the cell layer (18) comprising electrochemically active layers (20); providing an interconnector plate (28) having a periphery (30) and a central portion (32) surrounded by the periphery (30); providing a fluid guidance insert (52), said fluid guidance insert (52) comprising a plurality of elongate slots (54) formed therein, overlaying the cell layer (18) and the interconnector plate (28) with the fluid guidance insert (52) positioned therebetween, wherein the central portion (24) of the cell layer (18) and the central portion (32) of the interconnector plate (28) define a fluid volume (34) therebetween, wherein the cell unit (12) has at least one fluid port (42, 44) in fluidic communication with the fluid volume (34), and wherein said elongate slots (54) define a fluid channel system for conveying fluid between the at least one fluid port (42, 44) and the fluid volume (34).

52. A method of manufacture of a stack (10) of cell units (12), comprising: providing a plurality of cell units (12), each cell unit (12) according to any one of claims 1 to 39;overlaying the plurality of cell units (12) upon one another such that an interconnector plate (28) of a first cell unit (12) faces a cell layer (18) of a second, neighboring, cell unit (12), optionally with at least one gasket (50) disposed therebetween.

53. An electrochemical cell unit (12) comprising: a cell layer (18) comprising electrochemically active layers (20), and an interconnector plate (28), wherein the cell layer (18) and the interconnector plate (28) overlay one another in an opposed relationship and are spaced from one another to define a fluid volume (34) therebetween, wherein the cell unit (12) has at least one fluid port (42, 44) in fluidic communication with the fluid volume (34), and wherein a fluid guidance insert (52) is disposed in the fluid volume (34), said fluid guidance insert (52) comprising a plurality of elongate slots (54) formed therein, said elongate slots (54) defining a fluid channel system for conveying fluid between the at least one fluid port (42, 44) and the fluid volume (34).

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