Description:FORM - 2

THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
(See Section 10; Rule 13)

“FRAME FOR AN ELECTROLYSER CELL AND ELECTROLYSER CELL COMPRISING SUCH A FRAME”

Adani New Industries Limited
An Indian Company
having address at
ADANI CORPORATE HOUSE,
Near Vaishnodevi Circle, S. G. Highway,
Ahmedabad-382421, Gujarat, India.

The following specification particularly describes the invention and the manner in which it is to be performed:
FIELD OF THE INVENTION:
The present invention relates generally to the field of electrolysers for the production of hydrogen and oxygen by the water electrolysis process. More specifically, the present invention relates to a frame for an electrolyser cell, as well as to an electrolyser cell comprising such a frame and intended to be assembled with other identical cells according to a side-by-side arrangement to form a so-called cell stack.

BACKGROUND OF THE INVENTION:
An electrolyser cell typically includes a frame, which is designed to act as a structural component for the cell and is made of an electrically nonconductive material, usually a plastic material, and a bipolar plate, which is made of an electrically conductive material, usually metal, as well as, of course, a number of other components such as a cathode electrode, an anode electrode, a diaphragm, a number of gaskets, etc.
In order to be able to adequately perform its structural function, the frame of an electrolyser cell is typically manufactured by injection moulding process from a thermoplastic polymer, such as for example, PPOm (Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (polyphenylene ether), loaded with reinforcing fibres, especially glass fibres, and/or with a mineral filler, in a percentage generally between 30% and 60%. However, the production of a frame for an electrolyser cell made of such a material involves high manufacturing costs, as the addition of reinforcing fibres and/or mineral filler leads to higher costs both in terms of material procurement and in terms of the production process (due in particular to increased mould wear and thus to the need to overhaul or replace the mould more frequently). Furthermore, the addition of reinforcing fibres and/or mineral filler to the polymeric material of the frame results in an increase in the weight of that component. Therefore, there remains a need to solve this technical problem and provide an electrolyser for the production of hydrogen and oxygen by water electrolysis process and provide a frame for an electrolyser cell, as well as to an electrolyser cell comprising such a frame and intended to be assembled with other identical cells according to a side-by-side arrangement to form a so-called cell stack.

PRIOR ART AND ITS DISADVANTAGES:
In order to be able to adequately perform its structural function, the frame of an electrolyser cell is typically manufactured by injection moulding process from a thermoplastic polymer, such as for example, PPOm (Modified Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (polyphenylene ether), loaded with reinforcing fibres, especially glass fibres, and/or with a mineral filler, in a percentage generally between 30% and 60%. However, the production of a frame for an electrolyser cell made of such a material involves high manufacturing costs, as the addition of reinforcing fibres and/or mineral filler leads to higher costs both in terms of material procurement and in terms of the production process (due in particular to increased mould wear and thus to the need to overhaul or replace the mould more frequently). Furthermore, the addition of reinforcing fibres and/or mineral filler to the polymeric material of the frame results in an increase in the weight of that component.
OBJECTS OF THE INVENTION:
The main objective of the present invention is to provide a frame for an electrolyser cell that is able to overcome the drawbacks of the prior art discussed above
The principle objective of the present invention is to provide a frame for an electrolyser cell that is obtainable at a lower cost than the prior art.
Another objective of the present invention is to provide a frame for an electrolyser cell that has a lower weight than the prior art.
In summary, the present invention is based on the idea of having a frame made of two separate parts coupled to each other, namely a base part and a cover part, wherein the cover part is made of a polymeric material without reinforcing fibers or mineral filler, or at most with a low content (not exceeding 10%) of reinforcing fibers or mineral filler, while the base part is made of a polymeric material reinforced with fibers or mineral filler.
As a result of such a solution, the frame is less expensive to produce than the prior art because of the reduced cost of the material of the cover part and because of the reduced manufacturing cost of this part. Moreover, the frame is lighter than the prior art because of the reduced weight of the cover part, due to the lower mass density of the material of this part.
In addition, using for the cover part a polymeric material without reinforcing fibers or mineral filler, or at least with a low amount of reinforcing fibers or mineral filler (i.e., as mentioned above, no more than 10 percent), also makes it possible to improve the quality of the frame, in particular, to obtain a cover part with tighter geometric tolerances (particularly flatness tolerances) and dimensional tolerances and with lower surface roughness.

SUMMARY OF THE INVENTION
It is an object of the present invention to provide a frame for an electrolyser cell that is able to overcome the drawbacks of the prior art discussed above.
More particularly, it is an object of the present invention to provide a frame for an electrolyser cell that is obtainable at a lower cost than the prior art. A further object of the present invention is to provide a frame for an electrolyser cell that has a lower weight than the prior art.
These and other objects are fully achieved according to the present invention by virtue of a frame for an electrolyser cell as defined in the attached independent claim 1.
Additional advantageous aspects of the frame for an electrolyser cell according to the present invention are defined in the dependent claims, the subject matter of which is to be intended as forming an integral part of the following description.
In summary, the invention is based on the idea of having a frame made of two separate parts coupled to each other, namely a base part and a cover part, wherein the cover part is made of a polymeric material without reinforcing fibres or mineral filler, or at most with a low content (not exceeding 10%) of reinforcing fibres or mineral filler, while the base part is made of a polymeric material reinforced with fibres or mineral filler.
As a result of such a solution, the frame is less expensive to produce than the prior art because of the reduced cost of the material of the cover part and because of the reduced manufacturing cost of this part. Moreover, the frame is lighter than the prior art because of the reduced weight of the cover part, due to the lower mass density of the material of this part.
In addition, using for the cover part a polymeric material without reinforcing fibres or mineral filler, or at least with a low amount of reinforcing fibres or mineral filler (i.e., as mentioned above, no more than 10 percent), also makes it possible to improve the quality of the frame, in particular, to obtain a cover part with tighter geometric tolerances (particularly flatness tolerances) and dimensional tolerances and with lower surface roughness.

BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the present invention will result more clearly from the following description, given purely by way of non-limiting example with reference to the accompanying drawings, in which:
? Figure 1 is an exploded view of an electrolyser cell comprising a frame according to an embodiment of the present invention, with the frame being shown in the assembled condition.
? Figure 2 is an exploded view of the frame of the electrolyser cell of Figure 1;
? Figure 3 is a front view of the frame of Figure 2, in the assembled condition;
? Figure 4 is a view of the frame similar to that of Figure 3, but without the cover part of the frame; and
? Figure 5 is a sectional view, on an enlarged scale, of the frame of Figure 3, taken through the section plane indicated by lines V-V in Figure 3.
LIST OF REFERENCE NUMERALS
10 Frame
12 Bipolar plate
14 Diaphragm
16 Cathode electrode
18 Anode electrode
20 Cathode current collectors
22 Anode current collectors
24 Bipolar plate fastener
26 Diaphragm fastener
28, 30, and 32 Plurality of sealing gaskets
34 and 36 Frame parts
34a Anode flat face
34b Cathode flat face
34c Mounting flat face
36a External flat face
36b Internal flat face
38 and 40 Sealing gaskets
42 Central Opening
44 First hole
44’ and 44’’ Corresponding first holes
46 Second hole
46’ and 46’’ Corresponding second holes
48 Third hole
48’ and 48’’ Corresponding third holes
50 Fourth hole
50’ and 50’’ Corresponding fourth holes
52 Recessed portion
54 Perimetral shoulder
56 Plurality of first channels
58 Plurality of second channels
60 Groove formed on the external flat face
62 Plurality of third channels
64 Plurality of fourth channels
66 Groove formed on the mounting flat face

DETAILED DESCRIPTION OF THE INVENTION:
With reference first to Figure 1, an electrolyser cell suitable for use in electrolysers operating at low temperatures, particularly electrolysers known by the acronyms AEMWE (Anion Exchange Membrane Water Electrolyser), is shown in exploded view.
The electrolyser cell basically comprises, in a per-se-known manner, a frame (10), a bipolar plate (12), a diaphragm (14), a cathode electrode (16), an anode electrode (18), one or more cathode current collectors (20), one or more anode current collectors (22), a bipolar plate fastener (24), a diaphragm fastener (26), and a plurality of sealing gaskets (28, 30 and 32) of various shapes and/or types.
Regarding the bipolar plate (12), the diaphragm (14), the cathode electrode (16), the anode electrode (18), the cathode current collector(s) (20), the anode current collector(s) (22), the bipolar plate fastener (24), the diaphragm fastener (26), and the sealing gaskets (28), these are all components whose features are not relevant to the present invention. Therefore, these components will not be described in detail here.
Referring now to Figure 2, the frame (10) is not made as a single piece, like in the prior art, but comprises two separate frame parts (34 and 36), hereinafter referred to as the base part and cover part, respectively, as well as sealing gaskets (38 and 40) arranged between the base part (34) and the cover part (36).
The base part (34) is made of reinforced polymeric material, i.e., polymeric material containing reinforcing fibres and/or mineral filler, particularly with a percentage of reinforcing fibres or mineral filler greater than 10%. The polymeric material of the base part 34 preferably contains one or more thermoplastic polymers, for example (Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (Polyphenylene ether), or combinations thereof. Additives of various kinds may also be added to the polymeric material of the base part (34).
The cover part (36) is made of unreinforced polymeric material or rubber, i.e., polymeric material (in particular thermoplastic polymer, such as (Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (polyphenylene ether), or combinations thereof) or rubber (such as EPDM (Ethylene Propylene Diene Monomer)) containing no reinforcing fibres or mineral filler, or alternatively with a low percentage of reinforcing fibres and/or mineral filler, specifically with a percentage of reinforcing fibres and/or mineral filler not exceeding 10%. The material of the cover part 36 may also contain additives of various kinds, but without a reinforcing function.
With reference also to Figure 3, the frame (10) is configured substantially as a plate element that may have various shapes. In the proposed embodiment, the frame (10) has a rectangular shape with rounded vertices, but it may have any other suitable shape. The frame (10) has a central opening (42) defining, in a per-se-known manner, an active chamber of the electrolyser cell. The central opening (42) is formed in the base part (34) of the frame (10). In the proposed embodiment, the central opening (42) is rectangular in shape, but it may have any other suitable shape.
The frame (10) also has a plurality of holes for the inlet and outlet of the electrolyte solution, namely, a first hole (44) positioned near one of the vertices of the frame (10) (bottom left vertex, according to the point of view of a person looking at Figure 3), a second hole (46) positioned near the vertex of the frame (10) opposite to that of the first hole (44) (top right vertex according to the point of view of a person looking at Figure 3), a third hole (48) positioned near one of the other two vertices of frame (10) (bottom right vertex, according to the point of view of a person looking at Figure 3), and a fourth hole (50) positioned near the vertex of the frame (10) opposite to that of the third hole (48) (top left vertex, according to the point of view of a person looking at Figure 3). The first hole (44) of the frame (10) is formed by corresponding first holes (44' and 44") in the base part (34) and in the cover part (36), respectively, which are aligned with each other in the assembled condition of the frame (10). Likewise, the second hole (46) of the frame (10) is formed by corresponding second holes (46' and 46") in the base part (34) and in the cover part (36), respectively, which are aligned with each other in the assembled condition of the frame (10). Similarly, the third hole (48) of the frame (10) is formed by corresponding third holes (48' and 48") in the base part (34) and in the cover part (36), respectively, which are aligned with each other in the assembled condition of the frame (10), and the fourth hole (50) of the frame (10) is formed by corresponding fourth holes (50' and 50") in the base part (34) and in the cover part (36), respectively, which are aligned with each other in the assembled condition of the frame (10).
The holes (44', 46', 48' and 50') in the base part (34) are provided in a recessed portion (52) of this part, which extends around the central opening (42) and forms a perimetral shoulder (54) (which can be better seen in Figure 5) with the remaining portion of the base part (34). Therefore, the base part (34) comprises an internal portion (i.e., a portion facing the central opening (42)) with a reduced thickness, which is formed by the above-mentioned recessed portion (52), and an external portion extending around the recessed portion (52) and having a greater thickness. With reference also to Figure 5, the base part (34) thus has an anode flat face (34a), i.e., a flat face facing the anode side of the electrolyser cell, a cathode flat face (34b), i.e., a flat face facing the cathode side of the electrolyser cell, and a mounting flat face (34c), which is formed by the recessed portion (52) and serves to support the cover part (36) when the latter is mounted on the base part (34). Still with reference to Figure 5, the cover part (36) has an external flat face (36a), which in the assembled condition of the frame (10) is flush with the anode flat face (34a) of the base part (34), and an internal flat face (36b), which in the assembled condition of the frame (10) is in contact with the mounting flat face (34c) of the base part (34).
As shown in Figure 3, the first hole (44) and the second hole (46) of the frame (10) are in fluid communication with the central opening (42) via a plurality of first channels (56) and a plurality of second channels (58), respectively. The first channels (56) and the second channels (58) are made on the external flat face (36a) of the cover part (36). In the example of Figure 3 both the first channels (56) and the second channels (58) are three in number and are configured as straight channels, but they may be more or less than three and/or have a non-straight configuration (for example, at least in part curvilinear and/or with one or more changes of direction), with the aim of optimizing the flow distribution of the electrolyte solution between the first hole (44) and the central opening (42) as well as between the second hole (46) and the central opening (42). The sealing gasket (30) is mounted on the anode face of the frame (10), and more specifically in a groove (60) formed on the external flat face (36a) of the cover part (36) (see Figure 5), and extends around the first hole (44), the second hole (46) and the central opening (42) so as to hydraulically isolate the holes (44 and 46) and the opening (42), together with the associated first channels 56 and second channels (58), from the outside. The sealing gaskets (32), two in number, are also mounted on the anode face of the frame (10), and more specifically in respective grooves (not shown) formed on the external flat face (36a) of the cover part (36), one around the third hole (48) so as to hydraulically isolate that hole from the outside, and the other around the fourth hole (50) so as to hydraulically isolate that hole from the outside.
Referring now to Figure 4, the third hole (48) and the fourth hole (50) are in fluid communication with the central opening (42) by means of a plurality of third channels (62) and a plurality of fourth channels (64), respectively. The third channels (62) and the fourth channels (64) are made on the mounting flat face (34c) of the base part (34). In the example of Figure 4 both the third channels (62) and the fourth channels (64) are three in number and are configured as straight channels, but they may be more or less than three and/or have a non-straight configuration (for example, at least in part curvilinear and/or with one or more changes of direction), with the aim of optimizing the flow distribution of the electrolyte solution between the third hole (48) and the central opening (42) as well as between the fourth hole (50) and the central opening (42). The sealing gasket (38) is mounted between the base part (34) and the cover part (36), and more specifically in a groove (66) formed on the mounting flat face (34c) of the base part (34), and extends around the third hole (48), the fourth hole (50) and the central opening (42) so as to hydraulically isolate the holes (48 and 50) and the opening (42), together with the associated third channels (62) and fourth channels (64), from the outside. The sealing gaskets (40), two in number, are also mounted on the mounting flat face (34c) of the base part (34), and more specifically in respective grooves (not shown) formed on this face, one around the first hole (44) so as to hydraulically isolate that hole from the outside, and the other around the second hole (46) so as to hydraulically isolate that hole from the outside.
Finally, with reference again in particular to Figure 5, the base part (34) and the cover part (36) are mechanically coupled to each other to form the frame (10). The mechanical coupling between these two parts may be obtained either by interference fit, as in the illustrated embodiment, or by suitable mechanical fasteners, such as for example spring clips.
As it is clear from the above description, since according to the invention part of the frame (10) (i.e., the cover part (36)) is made of unreinforced polymeric material or rubber, while the remaining part (i.e., the base part (34)) is made of reinforced polymeric material, the frame (10) is still able to act as a structural element for the electrolyser cell in a manner similar to a frame made of fibre-reinforced polymeric material according to the prior art, but with lower production costs and weight than the prior art.
Moreover, since the aforementioned channels (56, 58, 62 and 64), through which the electrolyte solution flows between the holes (44, 46, 48 and 50) and the central opening (42), are obtained on faces of the frame (10) positioned at a distance from the cathode flat face (34b) (namely, on the external flat face (36a) of the cover part (36), as far as the channels (56 and 58) are concerned, and on the mounting flat face (34c) of the base part (34), as far as the channels (62 and 64) are concerned) and since the bipolar plate (12) is arranged on the side of the cathode flat face (34b), the electrolyte solution flowing through these channels will never be in direct contact with the bipolar plate (12), but only in contact with the material of the base part (34) and the cover part (36). This allows to minimize leakage currents in the electrolyser cell and, therefore, reduces the negative effect of these currents on the overall efficiency of the electrolyser cell.
The present invention has been described above with reference to a preferred embodiment thereof, but it is clear that other embodiments may be envisaged, which share with those described herein the same inventive core, as defined by the accompanying claims.

ADVANTAGES OF THE INVENTION:
A frame for an electrolyser cell of the present invention is able to overcome the drawbacks of the prior art discussed above.
A frame for an electrolyser cell of the present invention is obtainable at a lower cost than the prior art.
A frame for an electrolyser cell of the present invention has a lower weight than the prior art.
A frame for an electrolyser cell of the present invention is less expensive to produce than the prior art because of the reduced cost of the material of the cover part and because of the reduced manufacturing cost of this part.
A frame for an electrolyser cell of the present invention is lighter than the prior art because of the reduced weight of the cover part, due to the lower mass density of the material of this part.
Using for the cover part a polymeric material without reinforcing fibres or mineral filler, or at least with a low amount of reinforcing fibres or mineral filler (i.e., as mentioned above, no more than 10 percent), also makes it possible to improve the quality of the frame, in particular, to obtain a cover part with tighter geometric tolerances (particularly flatness tolerances) and dimensional tolerances and with lower surface roughness.

Claims:We Claim

1. A frame (10) for an electrolyser cell, comprising

a base part (34) with a central opening (42) configured to serve as an active chamber of the electrolyser cell, said base part (34) being made of reinforced polymeric material with reinforcing fibres and/or mineral filler in a percentage greater than 10%,
characterized in that it further comprises:
- a cover part (36) coupled with the base part (34), said cover part (36) being made of polymeric material or rubber without reinforcing fibres or mineral filler, or with a percentage of reinforcing fibres or mineral filler not exceeding 10%; and
- a plurality of sealing gaskets (38, 40) arranged between the base part (34) and the cover part (36).

2. The frame as claimed in claim 1, wherein the cover part (36) is made of a thermoplastic polymer, in particular PPOm (Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (polyphenylene ether), or a combination thereof.

3. The frame as claimed in claim 1, wherein the cover part (36) is made of EPDM (Ethylene Propylene Diene Monomer).

4. The frame as claimed in any one of the preceding claims, wherein the polymeric material of the base part (34) is a thermoplastic polymer, in particular PPOm (Polyphenylene oxide), PSU (Polyarylsulfones), PPS (Polyphenylene sulfide), PPE (polyphenylene ether), or a combination thereof.

5. The frame as claimed in any one of the preceding claims, wherein the base part (34) has a recessed portion (52), which extends around the central opening (42) and forms a perimetral shoulder (54) with a remaining portion of the base part (34), and wherein the cover part (36) is mounted in said recessed portion (52) of the base part (34).

6. The frame as claimed in claim 5, wherein the base part (34) has an anode flat face (34a) and a cathode flat face (34b), as well as a mounting flat face (34c) formed by the recessed portion (52), and wherein the cover part (36) has an external flat face (36a), which is flush with the anode flat face (34a) of the base part (34), and an internal flat face (36b), which is in contact with the mounting flat face (34c) of the base part (34).

7. The frame as claimed in claim 6, wherein the base part (34) and the cover part (36) have a plurality of holes (44, 46, 48, 50) aligned with each other and wherein a plurality of channels (56, 58, 62, 64) are provided on the external flat face (36a) of the cover part (36) and on the mounting flat face (34c) of the base part (34) to put said holes (44, 46, 48, 50) in fluid communication with the central opening (42).

8. The frame as claimed in claim 6 or claim 7, wherein at least one (38) of the sealing gaskets (38, 40) is arranged between the mounting flat face (34c) of the base part (34) and the internal flat face (36b) of the cover part (36).

9. The frame as claimed in any one of the preceding claims, wherein the base part (34) and the cover part (36) are mechanically coupled to each other, in particular by interference fit or by at least one mechanical fastener.

10. An electrolyser cell comprising a frame (10) as claimed in any one of the preceding claims.

11. The electrolyser cell as claimed in claim 10, further comprises a bipolar plate (12) arranged on a cathode side of the frame (10).

12. The electrolyser for producing hydrogen and oxygen by water electrolysis process, comprising a plurality of electrolyser cells as claimed in claim 10 or claim 11, said electrolyser cells being arranged side by side with each other.

Dated this 24th day of July, 2024.

____________________
GOPI JATIN TRIVEDI
IN/PA 993
Authorized Agent of Applicant

To,
The Controller of Patents,
The Patent Office,
At Mumbai.