DK202200133A1 - Method of electric current measurement in electrolyser stack and electrolyser - Google Patents

Abstract

A method of electric current measurement at an electrolyser cell stack is provided. The method comprises the following steps: to provide at least one sensor (11) having an element which is responsive to the presence of a magnetic flux and/or magnetic flux changes adjacent to an input or exit manifold channel (6, 7) outside of a current injector plate in the electrolyser stack, ensure an electric or a wireless connection between the sensor (11) and a recording and/or display device, supply an electrical potential difference between two current injector plates having the electrolyser cell stack arranged between them, capture a signal value indicative of magnetic flux and/or magnetic flux change at the sensor location by at least one sensor (11), make at least one signal value available for storage and/or transmission to a remote location through the wired and/or wireless connection.

Description

DK 2022 00133 A1 1

Method of electric current measurement in electrolyser stack and slectrolyser, in electrolysers of the stacked cell type where an alkaline water mixture is supplied to a range of individual! cells through a manifold channel for the purpose of obtaining slectrolysed hydrogen and oxygen, thers is bound to be an electrical potential difference belween the two cells or half cells residing next fo the current injector plates arranged at each end of a range of individual cells. This electrical potential difference 1 will inevitably lead to the generation of electric currents in the electrolyte uid in the manifolds dus to the slkaline nature of the electrolyte and followingly low ahmic rasistance in the uid, & is of interest to know the size of the electrical current running in the channels, and direct galvanic measuremernts are not practical due fo the high potential differences, the corrosive nature of the akaline fluid, and the pressure difference between the surroundings and the vessels inside the stack. An alternative to direct galvanic measurements of electric currents running in the electrolyte manifold channels is thus desired,

The invention compørises a method of sleciria current measuremant at an slectrolyser stack comprising the following steps: provide at least one sensor comprising an slement which is responsive fo the presence of a magnetic flux andior magnetic flux changes adjacent to an electrolyte manifold channel outside of a current injector plate in the slectralyser stack, ensure an electric or a wirsless connection between the sensor and a recording andfor display device, supply an electrical potential difference between two current injector plates having the coll stack arranged between them, capture at least 28 — one signal value indicative of magnetic flux andfor magnetic flux change at the sensor location by the at least one sensor, make the at least one signal value available for storage andfor transmission to a remote location through the wired andfor wireless connection,

The stectrolvte in the manifold channels may carry a significant current whan the stack — is energized by slectric current passing from one electric current injector plate to an opposed slectric current injector plate through the range of individual siectrolyser cells

DK 2022 00133 A1 2 residing between the two stlechrin current injector plates, The current in the manifold channel may be measured at a location just outside of the cell stack af the far side of the current injector plate, through which the electrolyte and gas manifold channels are passed The current measured at this location passes in or out of the stack and may thus be indicative of an undesirable condition within the stack, and it is Important that it ie registered, The end plate is usually made from ron and may, more or less directly, be coupled to a zero electrical potential such as earth, in any event, the various channels passing through the end plate are not necessarily electrically insulated therafrom. 41 Currents may thus pass in the end plate, and these currents are difficull to measure.

The presence of a sensor responsive to magnetic field andfør magnetic field changes clase to the manifold channels outside of the current injector plates in the stack, will make it possible to sense the magnetic feld caused by electric currents in the slectrolyte, and thus an indication of the current flux andfor current flux changes in the — electrolyte passing in the manifold channel may be obtained, The current in the channel may be observed between the first cell fuld connection and first short ovroult between channel fluid and the end plate, If the channel remains electrically isolated from the end plate, the currant in the channel may be observed evan outside of the and plate by the use of a sensor as described, The obiained current indication is transmitted fram the site of the sensor to a remote location to he recorded andfor displayed. Thershy, the current indicative signal becomes available for a contra unt for the plant and automatic changes may be instigated in response to detected current levels or current level changes.

In an embodtiment, an insulation plate is generated with a pocket, and arranged adjacent — to a backside of a current injector, whereby the packet is arranged fo surround af least one of the following: an electrolyte manifold channel, an oxygen manifold channel, or a hydrogen manifold channel, in a predetermined distance therefrom leaving a material rim around the respective channel, and whereby the at least one sensor is inserted inte the pocket, 80 — The insulator plate is there to snsure that the electrical potential of the ourrentinjecter, which is connected ta a supply of DC electricity during electrolysation, does nat also raside with the end plate. in pressurized stacks, the end plates are urged towards each

DK 2022 00133 A1 3 other in order to offset the internal pressure in the stack and contain the various products therein, Thus, the insulation plate will be subject to the pressunzation forces 85 and must be sufficiently strong to sustain the pressure forces between the end plate and the current injector plate, Thus, tampering with this insulation plate and embedding sensitive electronic equipment in it, requires careful considerstion of both mechanical and electrical complicated issues, in an embodiment, the pocket is arranged adjacent ta the current injector plate, such 70 that the insulation plate is complete and unbroken against the end plate. The pocket may in this case extend inte the current injection plate in a recess provided to this end adjacent to the insulation plate. Hers the sensor may be placed around the channel ta be observed, in which oase the overall thickness of the insulation plate does not need to be changed. 78 — In another embodiment, the pocket is provided adjacent fo the end plate, and thus the insulstor plate is unbroken and complete at the face abutling the current injector plate, in this embodiment, the pocket may extend into a recess adjacent fo the insulation plate and crested in the end plate around the channel to be observed, in which case the overall thickness of the insulation plate does not need to be changed, 89 In an embodiment, sgnals indicative of currents or current changes in all of the following: a catholyte manifold channel, an andivie manifold channel, a hydrogen manifold channel, and an oxygen manifold channel of a stack, are captured and made available for storage and/or transmission,

Ris preferred that the currents passing in both the eleotralyte manifold channels as well 85 asin both of the hydrogen and oxygen manifold channels are monitored. This allows for

J mors sensitive and precise measurement. Also, in some types of slectrolysers, the anolyte and the catholvte have separate flow circuits and in order to capture a current running between the anolyte and catholyte and not contributing to the slectrolysie process, electrical current levels in each of the manifold channels must be observed. 80 Electno current densities are also captured af the manifold channels leading produced gases away from the elecirolyser stack as in alkaline water electrolysers these manifold channels carry 8 mixture of anolvte and oxygen and a miklure of catholyte and

DK 2022 00133 A1 4 hydrogen respectively, and due to the presence of the slacirolyte in these two channels, an sisctric current density shall also be present within the channel. These current 88 magnitudes may also provide important information regarding the present state within the stack during electrolysation, and a feedback mechanism will be realizable based on such data, Hereby a more optimized operation of a multitude of stacks may be obtaned as such sntilies as electrical current feed and electralyte flows in individual stacks may be regulated. 180 In an embodiment, an G-ring or similar gasketing device is pressured towards the material of the material rim around sach of the manifold channels whereby the Q-ring is adapted fo reside in a u-shaped furrow in the current injector plate or in s u-shaped furrøw in the end plate and/or in a U-shaped furrow in the insulation plate.

The O-rings aid to uphold the pressure inside of the electrolyte manifold channels in 195 pressurized sisctrolysers, This pressure may be 40 bar or higher, | is thus required, that the material nm around the electralyte manifalds is sufficiently strong to withstand the pressure in the radial direction from within the channel, And thus, the matenal rim nesds to have some thickness, and a gasketing is needed against the neighbouring element, whather it be the electric current injector plate or the end plate, This gasketing is 110 assured by the O-ring. The ring is made from a suitably flexible material and is preferably inserted, at least partially, in a furrow in the current injector platefend plate to ensure Is position, Alternatively, or additionally, the gasket is positioned in a furrow in the insulator plate. in an embodiment of the method, a sensor is arranged with a core material having high magnetic permeability and is subject to the magnetic fjeld generated by the electric current in the manifold channel and further at least one of a hall sjement, and a coil is provided adjacent to the core material, and sn electric response signal originating from the hall element and/or the coll is made available for storage andfor fransmission to a remote location, 120 By having a magnetic core with high magnetic permeability, a coil and a hall sensor, a zerm-fux type sensor may be provided, whereby an electric current is fed through the vol, which wound around the core, in order to off-set the magnetic flux generated by

DK 2022 00133 A1 the electric current in the channel, The combined resulting magnetic flux in the core is measured by the hall element, which to this purpose is inserted into a radially shaped 128 — sit in the core. A small circuit including an amplifier is used to keep the signal from the hall sensor constant, and the output signal is the potential over the collfelsctric current passing through the coll, which must be maintained fo get the unchanged signal fram the hall sensor, Hereby a more precise sensor with a high sensitivity over a wide range may be provided, 130 His an option fo provide a call which is wound around the electrølyte channel and monitor currents and/or potentials pravoked in such a coil due to the current changes in the slectrolvte channel, Such a coll would be especially well sutted to monitor ripples in the slecino currents in the electrolyte channel, In theory, by continually integrating the signal from such a coll from the start, & would be possible fo obtain credible values for 135 DOC electric current levels in the channel in an embodiment, the pocket is provided with a depth in the thickness direction of the wsulator plate of no more than 4/5 of the insulate plate thickness.

Usually, the insudator plate does not need ta be thick as the electric potential difference between an end plate and the current injector plate is small, but in order to 140 accommodate the sensor, the plate needs to have a higher thickness, or t must be made from a material which is stronger and have improved electric insulation properties. However, in any case, a reasonable fraction of the plate thickness needs fo remain unscathed by the provision of the pocket, to safeguard both strength and slectrinat insulation properties in the region of the pocket, Thus, it is recommended that 145 a certain fraction of the thickness is saved for this purpose, such that the pocket depth is no more than 4/8 of the thickness of the insulalor plate, in an embodiment, the pocket is milled out in the insulator plate prior to the insertion of the sensor,

This may be especially advantageous if the insulsior plate is initially cut out from endless 180 lanes of material,

DK 2022 00133 A1 6

The pocket may be open towards the surroundings in the radial dirention, preferably in a general direction in which the distance between the manifold channel and a radial surface of the insulator plate is smallest. This embodiment allows for the sensor to be easily exchangeable, 185 — In an embodiment, in a stap prior to assembly of the stack, voids around the sensor are filed out with a hardenable resin, such that the insulator plate material in the pocket and sensor and fransmission element are embedded in the resin,

This embodiment will on the ang hand provide excellent protection af the sensor and transmitter, however on the other hand, ft will not allow exchange or dis-assembly of the f80 sensor and the transmitter. Also, with this embodiment the material rim around the manifold channel may be made thinner in the radial direction as pressure forces from the fluid in the channel may be absorbed by the hardened resin and the sensor itself and further dispersed in radial direction away from the channels, "Thin" in this cannection means that the material rim will nat be strong enough on iis own ta 185 withstand the radial pressure from the Nuids in the channel when pressurized.

In an embodiment, the sensor slement is inserted into the pocket prior to, during, or after the assembly of the stack.

By this method, it will be easy to provide a sensor in the stack which may be accessed and removed from the stack or inserted in the stack at will. if the pocket is not open to 170 the surroundings, insertion is only an option prior to or during assembly of a stack, whereas in configurations where the packet is open, the insertion may take place af any time, in a further smbodiment, the invention comprises an slectralyser having a stack of cells and embedded in the stack, cathalyte and snolyte manifolds adapted to feed catholyte 175 and anolyte ta respective catholyte and analyte cell chambers, wherein catholvte chambers further comprise a cathode adapted fo release hydrogen, and anolyte chambers comprise an anode adapted to release oxygen, when an electrolyte comprising alkaline water is supplied through the respective slectrolvte manifolds and wherein gas and elecirolvie manifolds are provided and adapted for the capture of the

DK 2022 00133 A1 7 1") produced gasses. is preferred that 2 pocket is provided around af least on of an slectrolyte input manifold channel, an oxygen output manifold channel, a hydrogen output manifold channel and placed at 3 predetermined distance from the respective channel and disposed in an insulator plate arranged between an end plate and a current injector plate at one end of the stack whereby the packet is adapted to scoommodate a

BE sensor.

A pocket of this nature shall allow a sensor such as a sensor responsive to magnetic fields to reside therein and be sufficiently close to the manifold channels to sense possible electric currents passing in the channed, Other types of sensars, such as microphones, accelerometers and thermo slements may be provided in the pockel in 180 order for other properties such as sound andfor vilsrational levels and temperatures in be monitored. ås the insulator residing between the end plates and the current injection plate is subject ta high pressure, it is not evident, that a packed for holding any kind of sensor might well be provided therein, Surprisingly, it has been determined that by slightly increasing the thickness of the insulator plate, it becomes possible to include 188 various kinds of sensars therein. in an embodiment, the insulator plate is comprised of two plates which are assembled face to face, where one of the plates comprises a cut-out corresponding fo the pocket, and where an annular element is provided around the channel surrounded by the pocket, Possibly, the two insulator plates and the annular elements are glued andfor 200 wedded to each other such that when pressurized between the end plate and the current injector plates, no fluid shall penelrate their intersection. In such an embodiment, the pocket may be stamped out from a plate element, which would make production fast and easy, in an embodiment, at least one magnetic fi» andior magnetics flux change responsive 205 — touchless sensor is arrangsd in the pocket whereby the sensor is adapled lo register values indicative of electric current densities andfor slestrin ourrent density changes in a respective manifold channel and whereby further a transmission element for wireless or wired fransmission of registered values is provided in the pocket along with the

SENSOT.

DK 2022 00133 A1 8

Magnetic fux is registerable by an slement such as a hall sensor, Further, a coil may be used to register magnetio flux changes, a coil is provided and has a number of windings around a manifold channel, any changes in the electric current level in the channel will he ragisterable as an electrical potential, One or the other or both of such elements may be provided in the pocket along with a fransmission element such as an 245 amplifier connected to 8 wire connection or a wireless transmitter, in a preferred embodiment, the pocket surrounds a manifold slectrolyser channel and is at least partially open to the surrounding, if an opening is provided, i? may extend along a radial surface of the insulation plate and allow access to the pocket from the outside. This allows sensors, amplifiers wire 224) connected! wireless fransmilters ta be inserted or removed from the pocket withowt taking the elecirolvser stack apart. in a preferred embodiment, the sensor comprises a hall element and at least one of the hø a magnetic material with 2 high magnetic permeability, a coil

A cars is usually made of magnetic material with a high magnetic permeability and is

WE used to confine and guide magnetic field lines. It is usually made of ferrimagnetic medal such as iron, of ferrimagnetic compounds such as ferrites. The high permeability, relative fo the surrounding material causes the magnetic field lines to be concentrated in the core material, With a hall element, the magnetic flux may be measured at the electralyte channel, however in order fo retain an improved signal to noise ratio and & 23) larger measurement window, # is preferred that the hall element is inserted in a care made as described which surrounds the channel paving only a narrow gap for the hall sensor, With this arrangement, the magnetic flux lines originating from the electric current in the channel shall he much concentrated at the hall element, i is further an advantage if a coil is provided around at least a part of the core, such that an stevirne 235 — current in the coll may off-set the magnetic flux therein originating from the stectric current in the ohennel. A zera-fux sensor may thaersby be provided which allows high precision megsuremsnis in 8 wide measurement range,

DK 2022 00133 A1 9 in an embodiment of the invention, if is preferred that the predefined distance is sufficient for the pressure in the channel to be contained, 240 In this embodiment, the predefined distance bebween the channel inner surface and the surfaces of the pocket which are closest to the channel is sufficient for the material of the insulator plate to keep its shape and position when pressures is raised in the channel.

Thereby an Q-ring or another gasketing device betwear the insulator plate and an opposed surface shall remain seated in its furrow, and no leaks are likely, 245 — In an embodiment, the sensor oroumsoribes the respective channel, and the pocket is filled out by the sensor andfør possible hardenable resin provided between the sensor parts and pocket walls, in this smbodment, either sensor body or a hardened resin shall provide a strengthening means, such that sven if the material nm bebween the pocket and the 250 channel is not in itself strong enough to contain the pressure, the stresses in the fim shall be offset hy straining the sensor andfor the resin around the sensor, in this way the predetermined distance outlining the size of the rim may be kept relatively small, such that the pressures inside the channel are transferred through the material rim and the sensor andfor the resin to the surrounding parts of the insulator plate, Any gasketing 255 means, such as an O-ring shall thus remain in place and provide the desired gasketing, sven if pressures inside the channel surpass the pressure carrying capacity of the material rim,

Various exemplifying and non-limiting embodimenis both as to constructions and to methods of operstion, together with additional objects and advantages thereof, will be 280 best understood from the following description of specific exemplifying and non-lniting embadiments when read in conjunction with the accompanying drawings. in the above embodiments i is taken for granted, that the sensor ia not subject to the pressure in the channel. However, it is an option to arrange the sensor inside the pressurized area, seating the O-rings nutside of the pocket. Such an srrangement would 285 explude any larger opening from the pocket io the surroundings, and generally not offer any important advantages.

DK 2022 00133 A1

The verbs "to comprise” and "to inchude™ are used in this document as open limitations that neither exclude nor requires the existence of unrecited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, i is fo be understood that the use of "a" or "an", Le, a singular form, throughout this document does not exclude a plurality.

Brief description of the figures.

Fig. 1 shows a 30 view of a pant of the insulation plate with the pocket, 278 Fig. 2 is a plane view of an insulation plate where pockets have been milled out,

Fig. 3 is a plane view of area D in Fig. 2 in enlarged scale,

Fig. 4 shows a section along lines F-F indicated in Fig, 3,

Fig. § is a section through a prior art elactrolyser,

Fy. & is an enlarged view of a part of the electralyser shown in Fig, 5, 280 Fig. 7 shows an enlarged view af the part af the electralyser shown in Fig, §,

Fig. 8 shows in schemeit: form the basic parts of a sensor,

Fu, 8 is the sensor shown in Fig, 8, however with a wireless transmitter and

Fig, 10 shows a schematic representation of the flow volumes inside a coll stack 1.

In Fig, 5 a prior art electrolyser 1 is shown in a 3D sectional view, and here a range of cell frames 2 are maintained under axial pressure hebween two and plates 3. At each end plate 3, a ourrent injector plate + is arranged, and the individual cell frames 2 are stacked between the two current injector plates 4, Allernate cell frames are associated 290 with a bipolar piste 30 and a diaphragm 29 respectively as known in the art, and diaphragms 28 and bipolar plates 30 are schematically seen in Fig, TO, Also in this figure, the anolyte chambers 34 and cathode chambers 28 as well as cathode 36 and anode 37 are shown. Also, the extend of a single cell 28 and the entire stack of cell 1 is indicated. 235 — In Fig, 5, a proximal endplate 3 is shown with four axdally through going channels: anolyte and catholyte input channels & respectively at one side and oxygen and hydrogen exit channel 7 respectively at an opposed side. One of oxygen and hydrogen

DK 2022 00133 A1 11 output channel 7 is shown in an enlarged sectional view in Fig, 8. This endarged view aliows the insulation plate 8 between the endplate 3 and the current injector plate 4 to

XX) be seen, in Fig. 7 an enlarged view of the channel in Fig. & is provided and Fig, 7 also illustrates how the channel 7 runs axially through the insulation plate 8, As further seen in this figure, current injector plate C-ring furrow 14 is provided with an O-ring 18. Further, an insulstor plate furrow Q is shown, also with an O-ring 15, The two O-rings 15, ones on 305 each side of the insulation plate 8 ensures leak tight connection through the insulation plate 8. A somewhat similar arrangement will be provided for the insulator plate with the packet 10 according fo the invention, with an O-ring furrow 8, where an O-ring may be seated and pressured towards the rim & around the channel 8.7. in Fig. 4, an enlarged section of an insulator plate § according to an embodiment of the 340 invention is shown. Furrows 8 are provided in the insulation plate 4 andfor in the sndplate andfor in the current injector plate,

As further seen in Figs. & and 7, a ohannet bushing 16 is inserted through the end plate, and the O-ring in the insulation plate furrow 8 contacts an end-part of the channel bushing 18, 345 Inthe 3D view of a part of an insulation plate 8 according to an embodiment of the invention in Fig, 1, a pocket TO is seen as well as the channels 7,8 and around each channel 8,7 a material rim 5 of the insulator plate 8 is left with the original insulator plate thickness. This maternal nm 5 may comprise a furrow 8 as best søen in Fig. 4. An Q-rning (nat shown in Fig. 4) may be mounted in the furrow 9. The Q-ring serves as a gasketing 220 means fowerds an abutting element — either the channel bushing 8 or the current injector plate 4. fn Fig. 1, the furrow is not disclosed, and in order ta secure the G-ring, a furrow may alternatively be provided in an abulling element the channel bushing 16, or the current injactor plate 4. in Figs. 2, Sand 4, a sensor 11 is schematicalty shown inside the pocket 10. The sensor 228 11 is adapted to be responsive to the presence of magnetic fields or magnetic field changes which are going to be present at this location due fo the channel 7,8 and the

DK 2022 00133 A1 12 sloctrin ourrents which are likely fo pass along in the channel 7,8 whenever the slectrolyser is powered up hy the presence of a DU potential difference between the wo current injector plates 4 in the presence of the electrolyte in the cells and in the 330 channels 8,7.

The sensor 11 may output an electrical signal, such as a current or an electrical potential, In Fig, 8 this is indinated by arrow V.… This signal may be digitized and transferred in any usual manner, such as by a wireless transmitter 22 (see Fig, $) or through electric connection cables to a recording or displaying device 17 as disclosed 335 in Fig, 8. Operators or digital surveillance and automated systems may now oversee the signal value or possible changes in the signal value, which ether on ils own or in combination with other information regarding the condition of the stack and the processes therein will give an indication of desirable or less desirable conditions,

Operators or the digitized system may make changes to the operation conditions of the 34) stack based on the recorded information fram the sensor 11.

The pocket 10 may be arranged by milling away material around the rim 35, and possibly the pocket 10 has at least one opening 12 facing the surroundings, HF the opening 12 is wide as shown in Fig, 1, the entire sensor 11 may be extracted therethrough also when the stack is assembled, As seen in Fig, 2, only a narrow opening 12 is provided in this embodiment. Here only a minor part of the sensor, such as a hall element 13 may be æxtracted therefrom in case a replacement is nesded, in an embodtrent such as shown in Figs. I + 4, a sensor 11 is provided at each of the anolyte and catholyte channels 8 ag wall as for the hydrogen and oxygen manifold channels 7. The oxygen and hydrogen exit manifold channels 7 carry a mixture of the 350 eteotrlyte and the produced oxygen and hydragen respectively. Due tu the slectralyie part of such a mixture being conductive in naturs, alsa in these channels an slectric current may be present and measured. | ja remarked, that in some kinds of slectralyser stacks, the anolyte and catholyte fluids are identical and may even be mixed in a tank prior fo ection into the stacks, and it is only the end points of the respective mamfolds: 355 either cathode chambers or anode chambers, that determine whether a particular manifold channel is a catholyte or anolyte channel

DK 2022 00133 A1 13

A sensor 11 is schematically shown in Fig, 8. Sensors of this kind are in themselves well known, and sdectric circuitry at the sensor may vary, giving rise to different electrical properties of the sensor. However, the sensors follow the same principle: the core 18 is 380 — provided around an electric lead 19, and in a radial sit opening 20 of the core 18, a hall element 13 is inserted. The core 18 ja made from ferromagnetic material with a high magnetic permeability such that the magnetic field generated around the lead 19 due to the passage of electri current therein, shall be focused by the core 18 in the slit opening 20. The hall element 13 in the sit opening 20 is thus exposed to an enhanced 3S magnetic field due ta the current in the lead 18, in the sensor shown in Fig. 8, further an slactrio coil 21 is wound around the core. By this measure, the current in the glectnc coll 21 may be chosen to kesp a predetermined output from the hall sensor, such ss a zero output, The size of the needed current to this end will provide a measure of the electrio current passing in the slsctric lead 18. 370 In case the insulation plate 8 is cut out from an endless lane of material, it is advantageous to mill out the pocket by conventional milling techniques. The insulation plate may be manufactured by other manufacturing techniques, such as by injection moulding and in this case, the pocket is simply made in the usual manner as a positive part of the one mould half, 38 The sensor 11 may be inserted in the pocket prior to the assembly of the stack, and a hardenable resin may be used to ll out sny vade left in the pocket between the sensor and the insulation plate, in this case, naturally the sensor is not easily exchangeable, however if will sil well protected in the pocket 10 and be insulated from seeping sloctrolyte material, which in case the electrolyser is an alkaline and pressurized 380 — electrolyser is both chemically very aggressive, and pressurized. The material rim § indicated in Fig. 4 may in such cases be made with less regard to material strength, as the stresses added to the rim from the internal pressure in the channel, shall be carried, at feast partially by the resin and the remaining insulafor plate. Further, a reinforcement ring (not shown) may be provided externally of the maternal rim fo increase its resfisnce 385 aganst the internal pressure in the channel it surrounds. Such a ring may be made from material containing fibres such as carbon-carbon composites, aramid fibres, or may be made from metal compositions or combinations thereof.

DK 2022 00133 A1 14 in a further embodiment such as shown in Fig, 4, a void above or around the sensor remains, and possibly a soft polymer or foamed material (not shown) is added to the 280 void or voids, prior to assembly of the stack to ensure that the sensor is maintained in a pradefined position.

This allows for the sensor to be removed from the stack, such as for the sxchange fhereof,

DK 2022 00133 A1 i Electralyser cell stack 2 cellframes 3 end plate 4 ourment injector plate 400 5 material rim 8 Anolyte and catholyte input manifold channels 7 Qxygen and hydrogen exit manifold channels 8 insulation plate 8 Insulator plate Q-ring furrow 405 18 Packet 11 Sensor 12 Qvening 13 Hall element 14 Current injector plate O-ring furrow 410 18 O-ring 18 Channel bushing 17 Remote location recording or displaying device 18 Core 18 Electric lead 418 20 Radial slit opening 21 Electric coll 22 Transmission element 23 RF capability indicator 24 Anclyte chamber 424 25 Catholvle chamber 26 Cathode 27 Anode £8 Single cell 28 Diaphragm 428 30 Bipolar plate

Claims (15)

DK 2022 00133 A1 16

1. Method of electric current measurement at an electrolyser cell stack (1) comprising the following steps: provide at least one sensor (11) having an element which is responsive to the presence of a magnetic flux and/or magnetic flux changes adjacent to an input or exit manifold channel (6, 7) outside of a current injector plate (4) in the electrolyser stack (1), ensure an electric or a wireless connection between the sensor (11) and a recording and/or display device (17), supply an electrical potential difference between two current injector plates (4) having the electrolyser cell stack (1) arranged between them, capture a signal value indicative of magnetic flux and/or magnetic flux change at the sensor location by the at least one sensor (11), make the at least one signal value available for storage and/or transmission to a remote location (17) through the wired and/or wireless connection.

2. Method as claimed in claim 1, characterised in that an insulation plate (8) is generated with a pocket (10), and arranged adjacent to a backside of a current injector plate (4), whereby the pocket (10) is arranged to surround at least one of an anolyte or catholyte input manifold channel (6), an oxygen or hydrogen exit manifold channel (7) in a predetermined distance therefrom leaving a material rim (5) around the respective channel, and whereby the at least one sensor (11) is inserted into the pocket (10).

3. Method as claimed in any of the above claims, characterized in that, signals indicative of electric currents or electric current changes in all of an anolyte input manifold channel (6) and a catholyte input manifold channel (6) and an oxygen exit manifold channel (7) and hydrogen exit manifold channel (7) of a cell stack (1) are captured and made available for storage and/or transmission.

4. Method as claimed in claim 2 or claim 3, characterized in that an O-ring (15) or similar gasketing device is pressured towards the material rim (5) around each of the manifold channels (6, 7) whereby the O-ring is adapted to reside in

DK 2022 00133 A1 17 a u-shaped furrow (14) in the current injector plate (4) or adapted to reside in a u-shaped furrow in the endplate and/or to reside in a u-shaped furrow in the insulation plate (9).

5. Method as claimed in any of the above claims, characterized in that, a sensor (11) is arranged in the pocket (10) with a core (18) having high magnetic permeability and is thereby subject to the magnetic field generated by the electric current in the respective manifold channel (6,7) and in that at least one of a hall element (13) and an electric coil (21) is provided adjacent to the core (18), and whereby an electric response signal originating from the hall element (13) and/or the electric coil (21) is made available for storage and/or transmission to a remote location.

6. Method as claimed in any of the above claims, characterised in that, the pocket (10) is provided with a depth in the thickness direction of the insulator plate (8) of no more than 4/5 of the insulator plate thickness.

7. Method as claimed in any of the above claims, characterised in that, the pocket (10) is milled out in the insulator plate (8) prior to the insertion of the sensor (11).

8. Method as claimed in any of the above claims, characterised in that, in a step prior to assembly of the electrolyser cell stack (1), voids around the sensor (11) are filled out with a hardenable resin, such that the insulator plate material around the pocket (10) and the sensor (11) and transmission element are embedded in the resin.

9. Method as claimed in any of claims 1 — 8, characterised in that, the sensor (11) is inserted into the pocket (10) prior to, during, or after the assembly of the electrolyser cell stack (1).

10. Electrolyser (1) comprising a stack of cells and embedded in the stack, catholyte and anolyte input manifolds (6) adapted to feed catholyte and anolyte

DK 2022 00133 A1 18 to respective catholyte and anolyte cell chambers (24, 25), wherein catholyte chambers (24) further comprise a cathode (26) adapted to release hydrogen, and anolyte chambers (25) comprise an anode (27) adapted to release oxygen, when an electrolyte comprising alkaline water is supplied through the respective manifolds (6) and wherein gas and electrolyte manifolds (7) are provided and adapted for the capture of the produced gasses, characterized in that, a pocket (10) is provided around at least one of an electrolyte manifold channel (7) and a gas and electrolyte manifold channel (7) and placed at a predetermined distance therefrom in an insulator plate (8) arranged between an end plate (3) and a current injector plate (4) at one end of the stack (1), whereby the pocket (10) is adapted to accommodate a sensor (11).

11. Electrolyser as claimed in claim 10, characterized in that, at least one magnetic flux and/or magnetic flux change responsive touchless sensor (11) is arranged in the pocket (10) whereby the sensor (11) is adapted to register values indicative of electric current densities and/or electric current density changes in a respective manifold channel (6, 7) and whereby additionally a transmission element (22) for wireless or wired transmission of registered values is provided in the pocket (10) along with the sensor (11).

12. Electrolyser as claimed in claim 10, characterized in that, the pocket (10) surrounds a manifold channel (6, 7) and is at least partially open to the surroundings. —

13.Electrolyser as claimed in any of the claims 10 — 12, characterized in that, the sensor (11) comprises a hall element (13) and at least one of the two: a material with a high magnetic permeability such as a core (18), a coil (12).

14. Electrolyser as claimed in any of the claims 10 — 13, characterized in that, the predefined distance is sufficient for the pressure in the channel to be contained.

DK 2022 00133 A1 19

15. Electrolyser as claimed in any of the claims 10 — 13, characterized in that, the sensor (11) circumscribes the respective channel (6, 7), and that the pocket (10) is filled out by the sensor and/or hardenable resin provided between the sensor parts and pocket walls.