Plate for an electrochemical cell assembly and electrochemical cell assembly

Abstract

The invention relates to plates for an electrochemical cell assembly (10), preferably fuel cell assembly or electrolyser cell assembly, comprising debris collection features formed in a surface of the plate. The invention also relates to an electrochemical cell assembly comprising such a plate. The invention also relates to a system comprising such an electrochemical cell assembly and a fluid circulation device for circulating a fluid through the electrochemical cell assembly.

Description

[0001] Title: Plate for an electrochemical cell assembly and electrochemical cell assembly

[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 a plate for an electrochemical cell assembly, and an electrochemical cell assembly comprising such a plate.

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

[0005] The present invention specifically relates to solid oxide cells (SOCs). Such solid oxide cells (SOCs) typically comprise an electrolyte layer formed from a solid oxide, e.g. from Yttria-stabilized zirconia (YSZ), Gadolinia-doped Ceria, or Cerium Gadolinium Oxide (CGO). SOCs can be run as solid oxide fuel cell (SOFC) or as solid oxide electrolyser cell (SOEC).

[0006] Typically, multiple of such cell units are stacked upon one another to form a "stack" of cell units. Said stack is commonly arranged between two end plates provided on opposite sides of the stack to form an electrochemical cell assembly. The end plates may serve as access points for supplying fluid from the outside of the electrochemical cell assembly to the stack of cell units. For example, at least one of the end plates may comprise a fluid port in the form of a through-hole for delivering fluid to the stack of cell units. In addition, an electrochemical cell assembly typically comprises one or more electrical isolation plates to electrically isolate the end plates from the stack of cell units. Such electrochemical cell assemblies are known, for example, from WO 2020 / 126486 Al or WO 2022 / 175679 A2.

[0007] It is an object of the present invention to increase robustness and thus performance of an electrochemical cell assembly.

[0008] According to a first aspect, there is provided a plate with the features of claim 1. The plate is configured for use in an electrochemical cell assembly, preferably fuel cell assembly or electrolyser cell assembly. The plate may be an endplate, preferably baseplate, of the electrochemical cell assembly. The plate may be an electrical isolation plate of the cell assembly. The plate comprises a through-hole forming a fluid inlet port, preferably air inlet port, preferably of the electrochemical cell assembly. The plate comprises one or more debris collection features for the collection of debris. The one or more debris collection features are formed in a surface of the plate. Said one or more collection features comprise at least one debris collection, and preferably guiding, channel that is fluidically connected to the fluid inlet port (through- hole).

[0009] The proposed plate having one or more debris collection features allows debris occurring in the cell assembly to accumulate in predefined areas, in particular in areas where there is a risk of electrical short. Advantageously, this helps to increase robustness and thus performance of the electrochemical cell assembly over its lifetime. As the debris collection channel is fluidically connected to the fluid inlet port, fluid, in particular air, entering the fluid inlet port may be used as a transport medium to efficiently carry debris away from high-risk areas to lower risk areas. That is, the proposed plate allows for an "active" debris management. Advantageously, due to the "active" debris transport the collection channel can have a relatively small cross-section compared to "passive" debris collection features, thus minimizing undesired fluid bypass around the stack.

[0010] The source of such debris may be internal or external to the stack. Internal debris may be due to corrosion of the cells or other metallic components. In such cases this debris would be highly conductive and may induce an electrical short between neighboring cells or other components. Non-conductive debris such as from insulation, gaskets etc. is also undesirable as it could damage the chemically active areas or other components within the electrochemical cell assembly if allowed to circulate within the electrochemical cell assembly (e.g. due to air / fuel flow). Damage to the cell chemistry (e.g. from other debris) may produce further debris. Such debris may form during operation of the stack (e.g. due to component degradation), or following electrochemical cell assembly manufacture. Debris may also come from external to the stack, from the system components or from impurities in the fluid streams.

[0011] The plate may take various shapes, for example, square, rectangular, or round. Preferably, the plate is substantially rectangular. Preferably, the plate extends flat or planar in a main plane.

[0012] Preferably, the one or more debris collection features, in particular the debris collection channel, are formed on a main surface of the plate, i.e. a surface parallel to the main plane. The one or more debris collection features, in particular the debris collection channel, may be formed by processing the plate. For example, the one or more debris collection features, in particular the debris collection channel, may be formed by locally milling out plate material. Alternatively, the one or more debris collection features, in particular the debris collection channel, may be provided by primary shaping of the plate, e.g. by casting.

[0013] The fluid inlet port (through-hole) may be a main inlet port of the electrochemical cell assembly, in particular for a configuration of the plate as endplate of the cell assembly. Thus, the fluid inlet port may serve as an access point for supplying fluid from the outside of the electrochemical cell assembly to the interior. Alternatively, the fluid inlet port may be fluidically connected to a main inlet port of the electrochemical cell assembly, in particular for a configuration of the plate as electrical isolation plate.

[0014] The through-hole forming the fluid inlet port may take various shapes, e.g. cylindrical, square, rectangular, etc. Preferably, the through-hole extends through the plate in a direction orthogonal to the main plain of the plate.

[0015] Preferably, the debris collection channel opens into the fluid inlet port. Thus, the debris collection channel may be directly fluidically connected to the fluid inlet port (through-hole). This proves advantageous with regards to an efficient debris transport along the debris collection channel. Preferably, the debris collection channel extends away from the fluid inlet port. More preferably, the debris collection channel extends away in a radial direction with respect to the fluid inlet port (through- hole).

[0016] Preferably, the debris collection channel is elongate. Thus, the debris collection channel may have a length which is greater than both its width and depth, for example at least twice as great.

[0017] The debris collection channel may at least in sections extend in a main extension direction of the plate. The debris collection channel may at least in sections extend parallel to an outer perimeter (outer edge) of the plate.

[0018] In some embodiments, the debris collection channel has an angled course along its longitudinal extent. As used herein, the term "longitudinal" is used to describe the direction along the main extension direction of the debris collection channel. Advantageously, this may allow to provide "guiding sections" for transporting debris away and "accumulation sections" for accumulating the debris. In particular, the debris collection channel may have sections that are aligned with a main flow direction (those sections may act as "guiding sections" to transport debris away) and sections that are inclined to said main flow direction (those sections may act as "accumulation sections" to accumulate and store debris). This allows to actively guide debris away from "high risk" areas towards "low risk" areas of the plate. In some embodiments, the debris collection channel may have straight sections that are inclined towards each other.

[0019] In preferred embodiments, the debris collection channel forms a closed loop at its distal end (i.e., at the end that is furthest apart from the fluid inlet port). Advantageously, the closed loop may serve as debris accumulation feature to "store" the debris. This helps prevent debris from being flushed away by air flow in the electrochemical cell assembly, and in particular, from being blown out of the electrochemical cell assembly. The debris collection channel may take various shapes. Preferably, the debris collection channel is formed by a groove or slot in the surface of the plate. Advantageously, this allows for easy manufacturing of the channel. In addition, a configuration as groove or slot facilitates accumulation of debris. In particular, the groove or slot may serve as a trap for debris. For example, debris originating from a stack of cell units arranged on the plate may fall down onto the surface of the plate due to gravity, move parallel to the surface of the plate (e.g. due to fluid flow) and then become trapped in the groove or slot. Advantageously, by tuning the geometry of the groove or slot, debris accumulation can be adjusted.

[0020] The debris collection channel, preferably the groove or slot, may be formed in various cross-sectional shapes. For example, the debris collection channel, preferably the groove or slot, may have at least in sections a square or rectangular cross-section. Alternatively, the debris collection channel, preferably the groove or slot, may have at least in sections a triangular cross-section. In some embodiments, the cross-section may change along the longitudinal extent of the debris collection channel, preferably the groove or slot. Advantageously, by adjusting a cross-section of the debris collection channel, the channel may be divided into guiding sections (e.g. having smaller cross-section) and accumulation sections (e.g. having larger cross-section).

[0021] Preferably, the debris collection channel, in particular the groove or slot, has a depth of more than 0.5 mm and preferably less than 10 mm. This has proven advantageous with regards to efficient accumulation of debris (prefers higher depth) and minimized air bypass (prefers lower depth).

[0022] In preferred embodiments, the plate further comprises an (outlet) through-hole forming a fluid outlet port, preferably air outlet port. The fluid outlet port (through-hole) may be a main outlet port of the electrochemical cell assembly, in particular for a configuration of the plate as endplate, preferably baseplate, of the cell assembly. Alternatively, the fluid outlet port may be fluidically connected to a main outlet port of the electrochemical cell assembly, in particular for a configuration of the plate as electrical isolation plate. Preferably, the plate is elongate, e.g. rectangular, and the inlet through-hole forming the fluid inlet port and the outlet through-hole forming the fluid outlet port are positioned at opposite longitudinal end portions of the plate.

[0023] Preferably, the debris collection channel extends in sections parallel to a main flow direction from the fluid inlet port to the fluid outlet port. Those sections may serve as "guiding sections" to transport debris away. Alternatively, but preferably in addition, the debris collection channel extends in sections inclined to said main flow direction. Those inclined sections may serve as "accumulation sections" for accumulating and thus storing debris. Advantageously, this enables debris to be actively guided away from high-risk areas towards low(er) risk areas. The main flow direction may be defined by an axis that runs through the respective centers of the through-holes (fluid ports).

[0024] Preferably, the debris collection channel, more preferably the one or more debris collection features, is fluidically separated from the fluid outlet port. Advantageously, this reduces the risk that debris is discharged from the electrochemical cell assembly into a downstream system. Preferably, a distal end of the debris collection channel is spatially separated from the fluid outlet port.

[0025] In some embodiments, the plate is an endplate, preferably baseplate, for the electrochemical cell assembly. Thus, the fluid inlet port and the fluid outlet port may serve as fluid access ports for transporting fluid between the exterior and the interior of the electrochemical cell assembly.

[0026] The endplate may be formed from a metallic material, e.g. metal or metal alloy. The endplate may have one or more additional through-holes forming a fuel port(s). The endplate may have a stepped crosssection.

[0027] The endplate may have a, preferably central, supporting area for supporting a stack of cell units of the electrochemical cell assembly. In such embodiments, it proves advantageous if the debris collection channel, at least in sections, is aligned with an outer edge of said supporting area. Thus, debris formed in the stack of cell units may be efficiently collected in the channel. As used herein, the term "supporting" does not necessarily mean direct contact between the two entities. For example, there may be provided an electrical isolation plate and / or current transmission plate between the endplate and the stack of cell units.

[0028] In some embodiments, the plate is an electrical isolation plate (in the following: isolation plate) for the electrochemical cell assembly. The isolation plate may be configured to be positioned between a charged component and an earthed component of the electrochemical cell assembly. Preferably, the isolation plate is configured to overlie an endplate, e.g. an endplate as described above, in the electrochemical cell assembly.

[0029] In some embodiments, the isolation plate further comprises at least one cut-out through the isolation plate for receiving a compression support element. In such embodiments, advantageously, the one or more debris collection features may comprise a debris collection area adjacent to said cut out, preferably a respective debris collection area adjacent to each of said cut-outs. Preferably, the cut-out or each of the cut outs may at least partially surrounded by a debris collection area.

[0030] Preferably, the debris collection area and the debris collection channel are formed on opposite sides of the isolation plate.

[0031] According to a second aspect, there is provided an electrochemical cell assembly comprising: at least one plate, and a stack of cell units, preferably arranged on said plate, wherein said stack of cell units comprises a plurality of cell units that are stacked upon one another along a stacking direction, said at least one plate comprises a through-hole forming a fluid inlet port, preferably air inlet port, of the cell assembly, and one or more debris collection features for the collection of debris formed in a surface of the plate, wherein said one or more collection features comprise at least one debris collection channel that is fl uidically connected to the fluid inlet port. Additional preferred features of the electrochemical cell unit may be realised as described above in connection with the first aspect.

[0032] Preferably, the plate is stacked with the stack of cell units. Preferably, the stack of cell units is arranged on the plate or at least supported by the plate. Preferably, the cell units and the plate overlay one another along the stacking direction.

[0033] Preferably, when seen along the stacking direction, the stack of cell units overlays a supporting area of the plate. In such embodiments, advantageously, the debris collection channel, at least in sections, may be aligned with an outer edge (outer perimeter) of said supporting area.

[0034] In preferred embodiments, the cell assembly further comprises a housing that defines a fluid volume around the stack of cell units. The plate may be located in said fluid volume (e.g. when the plate is an isolation plate). The plate may delimit said fluid volume together with the housing (e.g. when the plate is an endplate, preferably baseplate, of the cell assembly). The housing may be connected, preferably welded, to the plate. The plate may form part of the housing.

[0035] Preferably, the plate is arranged such that the one or more debris collection features are located within said fluid volume defined by the housing. As such, the debris collection features are configured to collect debris originating inside the fluid volume.

[0036] In some embodiments, a fluid flow path, in particular from the fluid inlet port to the fluid outlet port, is defined between an outer (lateral) edge of the stack of cell units (external perimeters of the cell units) and the housing. In such embodiments, advantageously, the debris collection channel may at least in sections be aligned with said fluid flow path. Said fluid flow path may form a bypass for fluid to bypass the stack of cell units.

[0037] In some preferred embodiments, the plate is an endplate, preferably baseplate, of the electrochemical cell assembly. Thus, according to a third aspect, there is provided an electrochemical cell assembly comprising: an endplate, and a stack of cell units, preferably supported by said endplate, wherein said stack of cell units comprises a plurality of cell units that are stacked upon one another along a stacking direction, said endplate comprises a through-hole forming a fluid inlet port, preferably air inlet port, of the electrochemical cell assembly, and one or more debris collection features for the collection of debris formed in a surface of the plate, wherein said one or more collection features comprise at least one debris collection channel that is fl uidically connected to the fluid inlet port.

[0038] In such embodiments, the cell assembly may further comprise an electrical isolation plate, the electrical isolation plate comprising a cut-out through the isolation plate for receiving a compression support element, and a debris collection area adjacent to said cut out.

[0039] Thus, according to a fourth aspect, there is provided an electrochemical cell assembly comprising: an endplate; a stack of cell units, preferably supported by said endplate; an electrical isolation plate interposed between the endplate and the stack of cell units, said isolation plate comprising a cut-out through the isolation plate for receiving a compression support element(s); wherein said endplate comprises a through-hole forming a fluid inlet port, preferably air inlet port, of the electrochemical cell assembly, and one or more debris collection features for the collection of debris formed in a surface of the plate, wherein said one or more collection features comprise at least one debris collection channel that is fl uidically connected to the fluid inlet port, said electrical isolation plate comprises a debris collection area adjacent to said cut out.

[0040] In embodiments comprising an isolation plate and an endplate, preferably the isolation plate is interposed between the end plate and the stack of cell units. Preferably, the isolation plate overlies the endplate along the stacking direction. Preferably, the debris collection area is formed on the side of the isolation plate that faces the endplate.

[0041] Preferably, the debris collection area formed in the electrical isolation plate is fl uidically connected to the debris collection channel formed in the endplate. Advantageously, this allows debris to be transported between the debris collection area formed in the electrical isolation plate and the debris collection channel formed in the endplate. Specifically, fluid entering the electrochemical cell assembly through the fluid inlet port of the endplate may be guided by the debris collection channel towards the debris collection area.

[0042] In some embodiments, the isolation plate may overlie the endplate such that the debris collection channel is closed by the isolation plate.

[0043] In some embodiments, the plate is an electrical isolation plate of the electrochemical cell assembly.

[0044] Thus, according to a fifth embodiment, there is provided an electrochemical cell assembly comprising: an electrical isolation plate, preferably formed from an electrically insulating material, and a stack of cell units, preferably supported by said isolation plate, (optionally): an endplate, wherein the electrical isolation plate is interposed between the endplate and the stack of cell units wherein said stack of cell units comprises a plurality of cell units that are stacked upon one another along a stacking direction, said electrical isolation plate comprises a through-hole forming a fluid inlet port, preferably air inlet port, of the electrochemical cell assembly, and one or more debris collection features for the collection of debris formed in a surface of the plate, wherein said one or more collection features comprise at least one debris collection channel that is fl uidically connected to the fluid inlet port.

[0045] In some embodiments, the isolation plate further comprises at least one cut-out through the isolation plate for receiving a compression support element(s). In such embodiments, advantageously, the one or more debris collection features may comprise a debris collection area adjacent to said cut out, preferably a respective debris collection area adjacent to each of said cut-outs.

[0046] According to a sixth aspect, there is provided an electrical isolation plate for an electrochemical cell assembly, the plate comprising a cut-out through the isolation plate for receiving a compression support element and a debris collection area adjacent to said cut out.

[0047] According to a seventh aspect, there is provided an electrochemical cell assembly comprising: an electrical isolation plate, preferably formed from an electrically insulating material, and a stack of cell units, wherein said stack of cell units comprises a plurality of cell units that are stacked upon one another along a stacking direction, said at least one electrical isolation plate comprises a cut-out through the isolation plate for receiving a compression support element; and a debris collection area adjacent to said cut out.

[0048] The following optional features and advantages are applicable to each aspect:

[0049] Preferably, the isolation plate is formed from an electrically insulating material. Preferably, the isolation plate comprises mica. The optional cut-out in the isolation plate may be provided in various ways. Preferably, the cut-out is configured as a through-hole extending through the isolation plate. Preferably, the through-hole is fully surrounded by the isolation plate in the lateral directions, i.e. directions that are perpendicular to the stacking direction. Thus, the cut-out may be spaced apart from an outer edge of the isolation plate. Alternatively, the cut-out may only partially be surrounded by the isolation plate in the lateral directions. Thus, the cut-out may be located at the outer edge of the isolation plate.

[0050] Preferably, the isolation plate comprises a periphery and a central portion surrounded by the periphery. In such embodiments, advantageously, the at least one cut-out is provided in the central portion of the isolation plate.

[0051] The debris collection area may take various shapes. In some embodiments, the debris collection area is formed by a local extension of the cross-section of the cut-out, preferably in a width direction of the cutout.

[0052] In some embodiments, the cut-out is delimited a wall of the isolation plate, wherein the debris collection area is formed by a, preferably step-like, groove or recess formed in said wall.

[0053] In preferred embodiments, the cut-out is rectangular having a width direction and a longitudinal direction perpendicular to said width direction. In such embodiments, advantageously, the groove or recess may be formed in one or both of two of two opposite walls delimiting the cut out and extending along the longitudinal direction.

[0054] Preferably, said longitudinal direction is inclined, preferably perpendicular, to a main flow direction, e.g. from a fluid inlet port of the isolation plate to a fluid outlet port of the isolation plate. Thus, the debris collection area may form a stop for debris being transported along the main flow direction.

[0055] The groove or recess forming a debris collection area of the isolation plate may, for example, have a square, rectangular or triangular cross section. In case of a square cross-sectional area, it has proven advantageous if the cross-sectional area is at least 1.5x1.5 square millimeter, preferably at least 2.0x2.0 square millimeter. In case of a triangular cross-sectional area, it has proven advantageous if the crosssection is characterized by at height of at least of 5 mm, preferably at least 8 mm with a minimum opening size being at least as large as the maximum debris particle size (1mm in one embodiment). The cross-sectional area of the triangle then enlarges to allow the debris particle to move freely. It has been found that an appropriate opening angle is 20 to 25 degree, preferably 22.5 degree.

[0056] In each of the above-described electrochemical cell assemblies comprising an electrical isolation plate having a cut out, preferably, the electrochemical cell assembly further comprises at least one compression support element positioned in said cut-out.

[0057] In some embodiments comprising at least one compression support element positioned in the cut-out of the isolation plate, preferably the debris collection area is formed at the interface of the isolation plate and the compression support element. In some examples, said debris collection area is formed by a, preferably step-like, groove or recess formed in the isolation plate, as described above. In some other examples, said debris collection area is formed by a groove or recess formed in the compression support element. In some other examples, said debris collection area is formed by a groove or recess formed in the isolation plate and by a, preferably adjacent, groove or recess formed in the compression support element.

[0058] The compression support element may take various shapes. The compression support element may be plate-shaped. The compression support element may be sleeve-shaped, elongate or cylindrical.

[0059] Preferably, the cut out is configured such that the compression support element is fully surrounded by the walls of the isolation plate delimiting the cut out.

[0060] Preferably, the compression support element is formed from a ceramic material. In some preferred embodiments, the ceramic material, i.e. the material of the compression support element, comprises alumina or consists of alumina. In preferred embodiments, the cell units each comprise a periphery and a central portion surrounded by the periphery, said central portion comprising a structured area having a plurality of protrusions formed therein, wherein the compression support element is positioned in said cut-out such that, seen along the stacking direction of the stack of cell units, the compression support element and the structured area of the cell units overlap each other at least partially.

[0061] According to an eight aspect, there is provided a system comprising an electrochemical cell assembly according to any one of aspects 2, 3, 4, 5, and 7, and a fluid circulation device for circulating a fluid, preferably air, through the fluid inlet port of the plate or plates.

[0062] Further embodiments are derivable from the following description and the drawings. In the drawings:

[0063] Figure 1 shows a perspective view of an electrochemical cell assembly;

[0064] Figure 2 shows a top view of the electrochemical cell assembly of Figure 1;

[0065] Figure 3 shows a top view of a baseplate of the electrochemical cell assembly;

[0066] Figure 4 shows a perspective view of the baseplate according to Figure 3 with an additional isolation plate overlaying the baseplate;

[0067] Figure 5 shows a bottom view of the isolation plate shown in Figure 4;

[0068] Figures 6 shows a schematic cross-section of a detail of the assembly according to Figure 5 along the cutting line VI-VI; and

[0069] Figures 7 shows an alternative configuration of the assembly as shown in Figure 6.

[0070] Repeat use of reference symbols in the present specification and drawings is intended to represent the same or analogous features or elements.

[0071] Figures 1 and 2 show a simplified sketch of an example configuration of an electrochemical cell assembly 10.

[0072] The electrochemical cell assembly 10 comprises an end plate 12 in the form of a baseplate 14, and a stack 16 of cell units 18 (also referred to as 'cell repeat units') supported by the baseplate 14. The stack 16 comprises a plurality of cell units 18 that are stacked upon each other along a stacking direction 20. As set out above, the cell units 18 may be fuel cell units, electrolyser cell units, or reversible cell units.

[0073] Each cell unit 18 extends in a respective cell plane perpendicular to the stacking direction 20 in a first direction 22 and in a second direction 24 perpendicular to the first direction 22. Each cell unit 18 defines an external perimeter 26 in said cell plane. Each cell unit 18 has a periphery 28 and a central portion 30 surrounded by the periphery 28. The central portion 30 carries electrochemically active layers 32 (see Fig- 2).

[0074] In the specific example shown, the cell units 18 are generally rectangular, albeit with shaped corners 34. As shown in Figure 1, in each of said shaped corners 34 there is provided an optional electrically insulating beam 36. In other embodiments, there may be beams 36 provided only on two of the shaped corners 34. In further embodiments, there may be no beams 36 provided. At least some of the beams 36 may carry a respective electrical connection member, in particular a busbar, of a current transmission system of the cell assembly 10. The beams 36 may be formed from mica.

[0075] The electrochemical cell assembly 10 further comprises a housing 38 surrounding the stack 16 of cell units 18.

[0076] Preferably, the electrochemical cell assembly 10 further comprises a second endplate in the form of a topplate (not shown) located at the end of the stack 16 of cell units 18 opposite the baseplate 14.

[0077] The housing 38 and the end plates 12 (baseplate 14 and optional topplate) together enclose a fluid volume 40, preferably for air or oxidant, around the stack 16 of cell units 18. The housing 38 may be welded to the baseplate 14 and / or the top plate.

[0078] In order to supply first fluid, preferably air or oxidant, to said fluid volume 40 and thus to the stack 16 of cell units 18, the electrochemical cell assembly 10 comprises a fluid inlet port 42 and a fluid outlet port 44 (see Fig. 2). In the example, the fluid inlet port 42 and the fluid outlet port 44 are each provided by a respective through-hole 46, 48 formed in the baseplate 14. As shown in Figure 2, preferably, the fluid inlet port 42 and the fluid outlet port 44 are located at opposite ends of the baseplate 14 along the first direction 22.

[0079] Referring to Figures 1, it can be seen that between the housing 38 and the long sides of the external perimeters 26 of the cell units 18, there are provided optional electrically insulating boards 50. In other embodiments, there may be no such boards 50. The boards 50 may be made of mica, although other electrically insulating materials, including many ceramics, can also be used.

[0080] In the following, an exemplary configuration of the baseplate 14 will be described in detail with reference to Figure 3.

[0081] In the example, the baseplate 14 is elongate wherein the inlet through-hole 46 forming the fluid inlet port 42 and the outlet through-hole 48 forming the fluid outlet port 44 are positioned at opposite longitudinal end portions of the baseplate 14.

[0082] In addition to said through-holes 46, 48 forming the fluid ports 42, 44 for the first fluid, the baseplate 14 comprises further through-holes 52, which serve as fluid supply ports 54 for supplying or discharging second fluid, preferably fuel, to the stack 16 of cell units 18.

[0083] The baseplate 14 further comprises debris collection features 56 for the collection of debris. Specifically, the baseplate 14 comprises two debris collection channels 58. Exemplarily, the two debris collection channels 58 are arranged mirror-symmetrically with respect to a middle axis of the baseplate 14. In other embodiments, there may be provided only one debris collection channel 58.

[0084] As schematically illustrated in the inset of Figure 3, the debris collection channels 58 are each formed by a groove 60 formed in a surface 62 of the baseplate 14. In the electrochemical cell assembly 10, said surface 62 faces the stack 16 of cell units 18. Exemplarily, the groove 60 has a rectangular cross-section. In other examples, however, the groove 60 may, e.g., have a triangular, square, rounded, circular cross-section.

[0085] Referring to Figure 3, it can be seen that each debris collection channel 58 opens into the fluid inlet port 42 (through-hole 46) at a respective distal end 64. Thus, the debris collection channels 58 are fluidical ly connected to the fluid inlet port 42.

[0086] In the specific example, the debris collection channels 58 each have an angular course along its longitudinal extent. Specifically, the debris collection channels 58 each comprise sections 66 that are oriented at an angle with respect to a main flow direction 68 from the fluid inlet port 42 to the fluid outlet port 44 (in the example parallel to the first direction 22) and a section 70 that is parallel to the main flow direction 68 (first direction 22).

[0087] At its respective distal end 72, the debris collection channels 58 comprise a closed loop 74. As set out above, the closed loop 74 may serve as a debris storage to collect debris that is transported along the channel 58 by fluid flow. Advantageously, the closed loop 74 is located at a position of one of said optional electrically insulating beams 36 mentioned above.

[0088] As shown in Figure 3, the baseplate 14 has a periphery 76 and a central portion 78 surrounded by the periphery 76. The central portion 78 forms a supporting area 80 for supporting the stack of cell units 18. Advantageously, the debris collection channel 58 is aligned with an outer edge of said supporting area 80.

[0089] Preferably, between the baseplate 14 (in particular the supporting area 80 of the baseplate 14) and the stack 16 of cell units 18 there is provided an electrical isolation plate 82 formed from an electrically insulating material (e.g. from mica or ceramic). Figure 4 shows such an isolation plate 82 in an overlaid position with the baseplate 14.

[0090] In the following, a preferred configuration of such an isolation plate 82 will be described with reference to Figures 4 to 6. As shown in Figure 4, the isolation plate 82 comprises a through-hole 84 forming a fluid inlet port 86 of the isolation plate 82. In the electrochemical cell assembly 10, said through-hole 84 of the isolation plate 82 and the (inlet) through-hole 46 of the baseplate 14 are aligned to guide first fluid, preferably air or oxidant, along the stacking direction 20 to the stack 16 of cell units 18.

[0091] In the specific example, the isolation plate 82 further comprises a recess 88 formed at the opposite longitudinal end to allow first fluid to pass to the fluid outlet port 44 (through-hole 48) of the baseplate 14. In other embodiments, the isolation plate 82 may comprise a second through-hole in fluid communication with the (outlet) through-hole 48 of the baseplate 14.

[0092] Referring to Figure 5, it can be seen that the isolation plate 82 comprises several cut-outs 90. The cut outs 90 are configured for receiving compression support elements of the electrochemical cell assembly 10. Specifically, the isolation plate 82 comprises two types of cut outs, i.e. first cut-outs 94 for receiving plate-like compression support elements 92a and second cut-outs 96 for receiving sleeve-like compression support elements 92b (see Figure 5).

[0093] The first cut outs 94 are located in a central portion of the isolation plate 82. Specifically, the cut outs 94 are provided such that, seen along the stacking direction 20, the cut outs 94 and the central portion 30 of the cell units 18 carrying the electrochemically active layers 32 at least partially overlap.

[0094] In the example, the first cut-outs 94 are elongate having a longitudinal direction 98 parallel to the second direction 24 and a width direction 100 parallel to the first direction 22. Specifically, the isolation plate 82 comprises three elongate first cut-outs 94 that are spaced apart from each other along a length direction of the isolation plate 82.

[0095] In each of said first cut out 94 there are provided one or more compression support elements 92a. For example, as schematically illustrated in Figure 5 for the left first cut out 94, there may be provided two elongate, plate-like compression support elements 92a in each cut out 94. The second type of cut outs 96 are located at the positions of the through-holes 52 forming the (second) fluid supply ports 54 of the baseplate 14. The second cut outs 96 are provided to receive sleeve-like compression support elements 92b (see Fig. 5). The sleeve-like compression support elements 92b, preferably also act as fluid guiding structure to guide second fluid, in particular fuel, through the isolation plate 82 to the stack 16 of cell units 18.

[0096] Referring to Figure 6, it can be seen that the isolation plate 82 comprises debris collection features 56 in the form of debris collection areas 102 adjacent to said first cut outs 94. Specifically, said debris collection areas 102 are provided by grooves 104 formed in the two opposite walls 106 of the isolation plate 82 that delimit the respective cut-out 94 along the longitudinal direction 98 (see Fig. 6). That is, the debris collection areas 102 are formed on the walls that are perpendicular to the main flow direction 68, thus serving as efficient traps for debris.

[0097] The grooves 104 may have a triangular cross-section (see Fig. 6). Alternatively, the grooves 104 may have a square cross-section (see Fig. 7). In even further examples, the grooves 104 may be a different shape. The triangular groove 104 in Fig. 6 is shown in enlarged view having a height y and an angle 0. In one example, the angle 0 is between 20-25 degrees, preferably 22.5 degrees. In one example, the height is 6-10 mm, preferably 8 mm. In one example, a spacing x between the isolation plate 82 and the compression support elements 92a is 1 mm.

[0098] Preferably, the grooves 104 are formed in the surface 108 of the isolation plate 82 that faces the baseplate 14, i.e. at the bottom face of the isolation plate 82 (see Fig. 6). In such a way, the debris collection area is formed at the interface of the isolation plate 82, compression support element 92a and baseplate 14.

[0099] In a similar fashion, there may be provided debris collection areas 102 in the form of grooves 104 around the second cut outs 96 (see Fig. 5).

[0100] As set out above, the debris collection areas 102 allow for the accumulation of debris. In particular, due to the additional free volume formed between the isolation plate 82 and the compression support elements 92a, b it can be avoided that debris accumulates and ultimately causes an electrical short between the stack 16 of cell units 18 and the baseplate 14.

[0101] While the Figures show the grooves 104 in the isolation plate 82 (see, e.g., Fig. 6 and 7), in other examples not shown, the grooves 104 are formed in the compression support elements 92a, b. In even further examples, there are grooves 104 provided in both the isolation plate 82 and the compression support elements 92a, b. The isolation plate 82 is likely made of a material more conducive to shaping, so making the grooves 104 in this plate would be simpler from a manufacturing perspective. As can be seen from Fig. 4, in the specific example, the isolation plate 82 further comprises an optional debris collection channel 110 at the side of the isolation plate 82 that faces the stack 16 of cell units 18, i.e. at the side opposite the debris collection areas 102. Exemplarily, the debris collection channel 110 is provided by a recess formed in the surface of the isolation plate 82. In other embodiments, the debris collection channel 110 may be formed as a groove similar to the debris collection channel 58 formed in the baseplate 14. The debris collection channel 110 is fluidically connected to the through-hole 84 (fluid inlet port 86) of the isolation plate 82, and thus can contribute to an "active" debris management.

Claims

Claims1. A plate for an electrochemical cell assembly (10) the plate comprising: a through-hole (46, 84) forming a fluid inlet port (42, 86), and one or more debris collection features (56) formed in a surface of the plate, wherein said one or more debris collection features (56) comprise at least one debris collection channel (58,110) that is fluidical ly connected to the fluid inlet port (42, 86).

2. The plate according to claim 1, wherein the debris collection channel (58, 110) opens into the fluid inlet port (42, 86).

3. The plate according to claim 1 or 2, wherein the debris collection channel (58, 110) extends away from the fluid inlet port (42, 86).

4. The plate according to any one of the preceding claims, wherein the debris collection channel (58) has an angled course along its longitudinal extent.

5. The plate according to any one of the preceding claims, wherein the debris collection channel (58) forms a closed loop (74) at its distal end (72).

6. The plate according to any one of the preceding claims, wherein the debris collection channel (58) is formed by a groove (60) or slot in the surface (62) of the plate.

7. The plate according to any one of the preceding claims, the plate further comprising a through- hole (48) forming a fluid outlet port (44), preferably air outlet port.

8. The plate according to the preceding claim, wherein the debris collection channel (58), preferably the one or more debris collection features (56), is fl uidically separated from the fluid outlet port (44).

9. The plate according to claim 7 or 8, wherein the debris collection channel (58) extends in sections parallel to a main flow (68) direction from the fluid inlet port (42) to the fluid outlet port (44) and preferably in sections inclined to said main flow direction (68).

10. The plate according to any one of the preceding claims, wherein the plate is an endplate (12), preferably baseplate (14), for the electrochemical cell assembly (10).

11. The place according to any one of claims 1 to 9, wherein the plate is an electrical isolation plate (82) formed from an electrically insulating material.

12. The plate according to the preceding claim, wherein the isolation plate (82) comprises at least one cut-out (90) through the isolation plate (82) for receiving a compression support element (92), wherein the one or more debris collection features (56) comprise a debris collection area (102) adjacent to said cut out (90).

13. The plate according to the preceding claim, wherein the debris collection area (102) and the debris collection channel (58) are formed on opposite sides of the isolation plate (82).

14. An electrical isolation plate (82) for an electrochemical cell assembly (10), the plate comprising: a cut-out (90) through the isolation plate (82) for receiving a compression support element (92; and a debris collection area (102) adjacent to said cut out (90).

15. The plate according to any one of claims 12 to 14, wherein the debris collection area (102) is formed by a local cross-section extension of the cut-out (90), preferably in a width direction (100) of the cut-out (90).

16. The plate according to any one of claims 12 to 15, wherein the debris collection area (102) is formed by a, preferably step-like, groove (104) or recess formed in a wall, preferably in one or both of two opposite walls, of the isolation plate delimiting the cut-out.

17. An electrochemical cell assembly (10), comprising the plate according to any one of the preceding claims, anda stack (16) of cell units (18), preferably arranged on said plate, said stack (16) of cell units (18) comprising a plurality of cell units (18) that are stacked upon one another along a stacking direction (20).

18. The electrochemical cell assembly (10) according to the preceding claim, wherein, seen along the stacking direction (20), the stack (16) of cell units (18) overlays a supporting area (80) of the plate, wherein the debris collection channel (58), at least in sections, is aligned with an outer edge of said supporting area (80).

19. The electrochemical cell assembly (10) according to claim 17 or 18, further comprising a housing (38) that defines a fluid volume (40) around the stack (16) of cell units (18).

20. The electrochemical cell assembly (10) according to the preceding claim, wherein the plate is arranged such that the one or more debris collection features (56) are located within said fluid volume (40).

21. The electrochemical cell assembly (10) according to any one of claims 17 to 20, wherein the plate is an endplate (12), preferably baseplate (14), of the electrochemical cell assembly (10).

22. The electrochemical cell assembly (10) according to the preceding claim, further comprising an electrical isolation plate (82), preferably according to claim 11, the electrical isolation plate (82) comprising a cut-out (90) through the isolation plate (82) for receiving a compression support element (92), and a debris collection area (102) adjacent to said cut out (90).

23. The electrochemical cell assembly (10) according to the preceding claim, wherein the isolation plate (82) is arranged between the endplate (12) and the stack (16) of cell units (18).

24. The electrochemical cell assembly (10) according to the preceding claim, wherein the debris collection area (102) is formed on the side (108) of the isolation plate (82) that faces the endplate (12).

25. The electrochemical cell assembly (10) according to any one of claims 22 to 24, wherein the debris collection area (102) formed in the electrical isolation plate (82) is fluidically connected to the debris collection channel (58) formed in the endplate (12).

26. The electrochemical cell assembly (10) according to any one of claims 22 to 25, wherein the debris collection area (102) is formed by a local cross-section extension of the cut-out (90), preferably in a width direction (100) of the cut-out (90).

27. The plate according to any one of claims 22 to 26, wherein the debris collection area (102) is formed by a, preferably step-like, groove (104) or recess formed in a wall, preferably in one or both of two opposite walls, of the isolation plate (82) delimiting the cut-out (90).

28. The electrochemical cell assembly (10) according to any one of claims 17 to 20, wherein the plate is an electrical isolation plate (82) according to any one of claims 11 to 16.

29. The electrochemical cell assembly (10) according to any one of claims 22 to 28, further comprising at least one compression support element (92) positioned in said cut-out (90) of the isolation plate (82).

30. The electrochemical cell assembly (10) according to the preceding claim, wherein the debris collection area (102) is formed at the interface of the isolation plate (82) and the compression support element (92a, 92b) by a, preferably step-like, groove (104) or recess formed in the isolation plate (82), preferably in a wall of the isolation plate (82) delimiting the cut-out (90), and / or by a groove or recess formed in the compression support element (92).

31. A system comprising the electrochemical cell assembly (10) according to of any one of claims 17 to 30, and a fluid circulation device for circulating a fluid, preferably air, through the fluid inlet port of the plate or plates.

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