Method and Apparatus of Electric Current Measurement in Electrolyser Stack and Electrolyser

Abstract

A method of electric current measurement at an electrolyser cell comprises the following steps: provide at least one sensor 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 outside of a current injector plate in the electrolyser stack, ensure an electric or a wireless connection between the sensor 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, make at least one signal value available for storage and/or transmission to a remote location through the wired and/or wireless connection. An electrolyser comprising a stack of cells where the electrolyser accommodates a sensor is also provided.

Claims

1. Method of electric current measurement at an electrolyser cell stack comprising the following steps: provide at least one sensor 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 outside of a current injector plate in the electrolyser stack, ensure an electric or a wireless connection between the sensor 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 the at least one sensor, make the at least one signal value available for storage and/or transmission to a remote location through the wired and/or wireless connection.

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

3. Method as claimed in claim 1, whereby signals indicative of electric currents or electric current changes in all of an anolyte input manifold channel and a catholyte input manifold channel and an oxygen exit manifold channel and hydrogen exit manifold channel of a cell stack are captured and made available for storage and/or transmission.

4. Method as claimed in claim 2, whereby an O-ring or similar gasketing device is pressured towards the material rim around each of the manifold channels whereby the O-ring is adapted to reside in a u-shaped furrow in the current injector plate or adapted to reside in a u-shaped furrow in an endplate and/or to reside in a u-shaped furrow in the insulation plate.

5. Method as claimed in claim 4, whereby a sensor is arranged in the pocket, said sensor having a core with high magnetic permeability and is thereby subject to the magnetic field generated by the electric current in the respective manifold channel and in that at least one of a hall element and an electric coil is provided adjacent to the core, and whereby an electric response signal originating from the hall element and/or the electric coil is made available for storage and/or transmission to a remote location.

6. Method as claimed in claim 2, whereby the pocket is provided with a depth in the thickness direction of the insulator plate of no more than ⅘ of the insulator plate thickness.

7. Method as claimed in claim 6, whereby the pocket is milled out in the insulator plate prior to the insertion of the sensor.

8. Method as claimed in claim 2, whereby, in a step prior to assembly of the electrolyser cell stack, voids around the sensor are filled out with a hardenable resin, such that the insulator plate material around the pocket and the sensor and transmission element are embedded in the resin.

9. Method as claimed in claim 2, the sensor is inserted into the pocket prior to, during, or after the assembly of the electrolyser cell stack.

10. Electrolyser comprising a stack of cells and embedded in the stack, catholyte and anolyte input manifold channels adapted to feed catholyte and anolyte to respective catholyte and anolyte cell chambers, wherein catholyte chambers further comprise a cathode adapted to release hydrogen, and anolyte chambers comprise an anode adapted to release oxygen, when an electrolyte comprising alkaline water is supplied through the respective manifold channels and wherein gas and electrolyte manifold channels are provided and adapted for the capture of produced gasses, whereby a pocket is provided around at least one of an electrolyte manifold channel and a gas and electrolyte manifold channel and placed at a predetermined distance therefrom in an insulator plate arranged between an end plate and a current injector plate at one end of the stack, whereby the pocket is adapted to accommodate a sensor.

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

12. Electrolyser as claimed in claim 10, wherein the pocket surrounds a manifold channel and is at least partially open to the surroundings.

13. Electrolyser as claimed in claim 11, wherein the sensor comprises a hall element and at least one of the two: a material with a high magnetic permeability such as a core, a coil.

14. Electrolyser as claimed in claim 10, the predefined distance is sufficient for the pressure in the channel to be contained.

15. Electrolyser as claimed in claim 10, wherein the sensor circumscribes the respective channel, and that the pocket is filled out by the sensor and/or hardenable resin provided between the sensor parts and pocket walls.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] FIG. 1 shows a 3D view of a part of the insulation plate with the pocket,

[0042] FIG. 2 is a plane view of an insulation plate where pockets have been milled out,

[0043] FIG. 3 is a plane view of area D in FIG. 2 in enlarged scale,

[0044] FIG. 4 shows a section along lines F-F indicated in FIG. 3,

[0045] FIG. 5 is a section through a prior art electrolyser,

[0046] FIG. 6 is an enlarged view of a part of the electrolyser shown in FIG. 5,

[0047] FIG. 7 shows an enlarged view of the part of the electrolyser shown in FIG. 6,

[0048] FIG. 8 shows in schematic form the basic parts of a sensor,

[0049] FIG. 9 is the sensor shown in FIG. 8, however with a wireless transmitter,

[0050] FIG. 10 shows a schematic representation of the flow volumes inside a cell stack 1 and

[0051] FIG. 10A shows the essentials of FIG. 10 in black and white.

DETAILED DESCRIPTION

[0052] 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 between two end plates 3. At each end plate 3, a current injector plate 4 is arranged, and the individual cell frames 2 are stacked between the two current injector plates 4. Alternate cell frames are associated with a bipolar plate 30 and a diaphragm 29 respectively as known in the art, and diaphragms 29 and bipolar plates 30 are schematically seen in FIG. 10. Also in this figure, the anolyte chambers 24 and cathode chambers 25 as well as cathode 26 and anode 27 are shown. Also, the extend of a single cell 28 and the entire stack of cell 1 is indicated.

[0053] In FIG. 5, a proximal endplate 3 is shown with four axially through going channels: anolyte and catholyte input channels 6 respectively at one side and oxygen and hydrogen exit channel 7 respectively at an opposed side. One of oxygen and hydrogen output channel 7 is shown in an enlarged sectional view in FIG. 6. This enlarged view allows the insulation plate 8 between the endplate 3 and the current injector plate 4 to be seen.

[0054] In FIG. 7 an enlarged view of the channel in FIG. 6 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 O-ring furrow 14 is provided with an O-ring 15. Further, an insulator plate furrow 9 is shown, also with an O-ring 15. The two O-rings 15, one on 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 pocket 10 according to the invention, with an O-ring furrow 9, where an O-ring may be seated and pressured towards the rim 5 around the channel 6,7.

[0055] In FIG. 4, an enlarged section of an insulator plate 8 according to an embodiment of the invention is shown. Furrows 9 are provided in the insulation plate 4 and/or in the endplate and/or in the current injector plate.

[0056] As further seen in FIGS. 6 and 7, a channel bushing 16 is inserted through the end plate, and the O-ring in the insulation plate furrow 9 contacts an end-part of the channel bushing 16.

[0057] In the 3D view of a part of an insulation plate 8 according to an embodiment of the invention in FIG. 1, a pocket 10 is seen as well as the channels 7,6 and around each channel 6,7 a material rim 5 of the insulator plate 8 is left with the original insulator plate thickness. This material rim 5 may comprise a furrow 9 as best seen in FIG. 4. An O-ring (not shown in FIG. 4) may be mounted in the furrow 9. The O-ring serves as a gasketing means towards an abutting element—either the channel bushing 6 or the current injector plate 4. In FIG. 1, the furrow is not disclosed, and in order to secure the O-ring, a furrow may alternatively be provided in an abutting element: the channel bushing 16, or the current injector plate 4.

[0058] In FIGS. 2, 3 and 4, a sensor 11 is schematically shown inside the pocket 10. The sensor 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 to the channel 7,6 and the electric currents which are likely to pass along in the channel 7,6 whenever the electrolyser is powered up by the presence of a DC potential difference between the two current injector plates 4 in the presence of the electrolyte in the cells and in the channels 6,7.

[0059] The sensor 11 may output an electrical signal, such as a current or an electrical potential. In FIG. 8 this is indicated by arrow V.sub.out. This signal may be digitized and transferred in any usual manner, such as by a wireless transmitter 22 (see FIG. 9) or through electric connection cables to a recording or displaying device 17 as disclosed in FIG. 8. Operators or digital surveillance and automated systems may now oversee the signal value or possible changes in the signal value, which either on its 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 stack based on the recorded information from the sensor 11.

[0060] The pocket 10 may be arranged by milling away material around the rim 5, and possibly the pocket 10 has at least one opening 12 facing the surroundings. If 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 extracted therefrom in case a replacement is needed.

[0061] In an embodiment such as shown in FIGS. 2-4, a sensor 11 is provided at each of the anolyte and catholyte channels 6 as well as for the hydrogen and oxygen manifold channels 7. The oxygen and hydrogen exit manifold channels 7 carry a mixture of the electrolyte and the produced oxygen and hydrogen respectively. Due to the electrolyte part of such a mixture being conductive in nature, also in these channels an electric current may be present and measured. It is remarked, that in some kinds of electrolyser stacks, the anolyte and catholyte fluids are identical and may even be mixed in a tank prior to injection into the stacks, and it is only the end points of the respective manifolds: either cathode chambers or anode chambers, that determine whether a particular manifold channel is a catholyte or anolyte channel.

[0062] A sensor 11 is schematically shown in FIG. 8. Sensors of this kind are in themselves well known, and electric 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 provided around an electric lead 19, and in a radial slit opening 20 of the core 18, a hall element 13 is inserted. The core 18 is made from ferromagnetic material with a high magnetic permeability such that the magnetic field generated around the lead 19 due to the passage of electric current therein, shall be focused by the core 18 in the slit opening 20. The hall element 13 in the slit opening 20 is thus exposed to an enhanced magnetic field due to the current in the lead 19. In the sensor shown in FIG. 8, further an electric coil 21 is wound around the core. By this measure, the current in the electric coil 21 may be chosen to keep a predetermined output from the hall sensor, such as a zero output. The size of the needed current to this end will provide a measure of the electric current passing in the electric lead 19.

[0063] 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.

[0064] The sensor 11 may be inserted in the pocket prior to the assembly of the stack, and a hardenable resin may be used to fill out any voids left in the pocket between the sensor and the insulation plate. In this case, naturally the sensor is not easily exchangeable, however it will sit well protected in the pocket 10 and be insulated from seeping electrolyte material, which in case the electrolyser is an alkaline and pressurized electrolyser is both chemically very aggressive, and pressurized. The material rim 5 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 least partially by the resin and the remaining insulator plate. Further, a reinforcement ring (not shown) may be provided externally of the material rim to increase its resilience against 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.

[0065] 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 void or voids, prior to assembly of the stack to ensure that the sensor is maintained in a predefined position. This allows for the sensor to be removed from the stack, such as for the exchange thereof.

1. REFERENCE NUMBERS

[0066] 1 Electrolyser cell stack [0067] 2 cell frames [0068] 3 end plate [0069] 4 current injector plate [0070] 5 material rim [0071] 6 Anolyte and catholyte input manifold channels [0072] 7 Oxygen and hydrogen exit manifold channels [0073] 8 Insulation plate [0074] 9 Insulator plate O-ring furrow [0075] 10 Pocket [0076] 11 Sensor [0077] 12 Opening [0078] 13 Hall element [0079] 14 Current injector plate O-ring furrow [0080] 15 O-ring [0081] 16 Channel bushing [0082] 17 Remote location recording or displaying device [0083] 18 Core [0084] 19 Electric lead [0085] 20 Radial slit opening [0086] 21 Electric coil [0087] 22 Transmission element [0088] 23 RF capability indicator [0089] 24 Anolyte chamber [0090] 25 Catholyte chamber [0091] 26 Cathode [0092] 27 Anode [0093] 28 Single cell [0094] 29 Diaphragm [0095] 30 Bipolar plate