Measuring device, electrochemical energy converter and method for measuring local current distribution and / or local heat distribution in an electrochemical energy converter

Abstract

The invention relates to a measuring device (10) for measuring local current distribution and / or local heat distribution in an electrochemical energy converter (12), the measuring device (10) comprising a plurality of resistance measuring means (14), a plurality of measuring segments (21), and at least one first plate (18) and one second plate (20), at least the first plate (18) and the second plate (20) each having a contact surface (44) for electrically contacting at least one electrochemical functional unit (46) of the electrochemical energy converter (12), and resistance measuring means (14) being electrically conductively connected to the contact surface (44) of at least the first plate (18) and to the contact surface (44) of at least the second plate (20) and being arranged between at least the first plate (18) and the second plate (20), and at least the first plate (18) and the second plate (20) being or becoming separated into specified surface regions (64), and measuring segments (21) comprising at least one of the following: - a measuring segment (21) is associated with a specified surface region (64); - at least one resistance measuring means (14) is associated with a measuring segment (21); - at least one temperature-sensitive element (16) is associated with a measuring segment (21).

Description

[0001] Measuring device, electrochemical energy converter and method for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter

[0002] The invention relates to a measuring device for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter.

[0003] Furthermore, the invention relates to an electrochemical energy converter.

[0004] Furthermore, the invention relates to a method for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter.

[0005] From DE 103 92 974 T5 a sensor arrangement for measuring an operating parameter of a fuel cell is known.

[0006] From WO 2005 / 096001 Al a device for determining the current density distribution in fuel cells is known.

[0007] From DE 10 2004 014 493 B4 a method for determining the current density distribution in fuel cells is known.

[0008] From DE 101 51 601 B4 a gas distribution element for supplying reaction gas to one or more electrochemical electrodes is known.

[0009] From DE 103 16 117 B3, a measuring device for measuring the local current / heat distribution at an electrochemical electrode, comprising a plurality of measuring segments, is known. The invention is based on the objective of providing an improved measuring device.

[0010] This problem is solved according to the invention in the measuring device mentioned at the outset by the fact that the measuring device comprises a plurality of resistance measuring devices, a plurality of measuring segments, and at least one first plate made of an electrically conductive material and a second plate made of an electrically conductive material, wherein resistance measuring devices each comprise a conducting device and / or a connecting device and at least one resistive element, wherein at least the first plate and the second plate each have a contact surface for electrically contacting at least one electrochemical functional unit of the electrochemical energy converter.and wherein resistance measuring devices or a selection of resistance measuring devices are electrically conductively connected to the contact surface of at least the first plate and to the contact surface of at least the second plate by means of the respective conducting device and / or connection device and are arranged between at least the first plate and the second plate, and wherein at least the first plate and the second plate are or are divided into predetermined surface areas, and wherein measuring segments comprise at least one of the following: a measuring segment is assigned to a predetermined surface area; at least one resistance measuring device is assigned to a measuring segment; at least one temperature-sensitive element is assigned to a measuring segment. The measuring device according to the invention enables, by means of resistance measuring devices and / or temperature-sensitive elements in an electrochemical energy converter,in particular in an electrolysis cell and / or an electrolysis stack and / or a fuel cell and / or a fuel cell stack, the measurement of a current distribution and / or current density distribution and / or heat distribution, for example with reference to contact surfaces of at least the first plate and at least the second plate.

[0011] In particular, the measuring device within the electrochemical energy converter is aligned such that the current flow occurs in a direction transverse, and especially perpendicular to, contact surfaces.

[0012] The first and second plates are preferably made of an electrically conductive material, so that the influence on measured values ​​is kept to a minimum and improved measurement quality is achieved.

[0013] For the same reason, it is advantageous if at least the first plate and the second plate are made of a thermally conductive material.

[0014] Contact surfaces are primarily closed surfaces.

[0015] Electrical contacting of the electrochemical functional unit of the electrochemical energy converter, and thus an electrical connection, is made possible via the contact surfaces of at least the first plate and the second plate.

[0016] The electrochemical functional unit comprises, for example, at least one bipolar plate and / or at least one electrode and / or one end plate and / or at least one porous transport layer (PTL) and / or at least one catalyst-coated membrane (CCM) and / or at least one gas diffusion layer (GDL). Resistance measuring devices preferably each have a conductor and / or connection device by means of which they are electrically connected to the respective contact surfaces.

[0017] At least the first plate and the second plate are, or will preferably be, divided into predefined surface areas. In particular, the respective contact surfaces are, or will be, divided into predefined surface areas. For example, a measuring segment is, or will be, assigned to each predefined surface area.

[0018] The measuring segments are connected to each other, particularly via electrical conductors.

[0019] In particular, each measuring segment is assigned at least one resistance measuring device and / or at least one temperature-sensitive element.

[0020] This allows for the spatial separation of the quantities to be measured, such as current or temperature, with respect to contact surfaces and their assignment to one or more measurement segments, each of which is specifically assigned to a predefined area. Values ​​can thus be measured with local resolution in each measurement segment, enabling the representation of the distribution of the measured values ​​across the contact surfaces.

[0021] This means that it is possible to represent the local activity of the chemical reaction in the electrochemical energy converter based on the measured values.

[0022] Resistance measuring devices are advantageously arranged between the first and second plates. This encapsulates the resistance measuring devices, minimizing wear, for example, from surrounding process media. Furthermore, it reduces the introduction of contaminants, such as those from the resistance measuring devices, into the electrochemical energy converter.

[0023] For high spatial resolution, it is advantageous if at least one of the following is provided:

[0024] The measuring segments are spaced apart from each other;

[0025] Each measuring segment has a geometric center point, with adjacent measuring segments having a distance from geometric center point to geometric center point of at least 10 mm from each other;

[0026] The measurement segments have at least approximately the same area.

[0027] The spacing of adjacent measurement segments determines, in particular, the spatial resolution of the quantities to be measured, i.e., the distance at which values ​​can be measured.

[0028] The desired resolution is defined based on the selected distance between adjacent measurement segments, in particular the distance from geometric center to geometric center.

[0029] For example, the spatial resolution is higher when adjacent measurement segments are close together than when they are further apart.

[0030] Furthermore, the measuring device can be scaled with respect to its geometric dimensions, enabling its use in various geometrically dimensioned electrochemical energy converters. Preferably, the measuring segments have at least approximately the same area. This contributes to improved measurement quality, as measurement uncertainties are kept low. "At least approximately" means that the area of ​​the measuring segments differs from each other by at most 10%, and particularly by at most 5%.

[0031] For a simple, constructive implementation, at least one of the following is provided:

[0032] Measuring segments are arranged in a structured grid;

[0033] The measuring segments are arranged in a regular grid;

[0034] Measuring segments are arranged radially around a center point;

[0035] Measuring segments are arranged point-symmetrically around a center point.

[0036] For example, measurement segments are or form a structured and / or regular grid.

[0037] An arrangement in a structured grid means, in particular, that a grid of measurement segments has a regular topology. For example, it could be an arrangement in a curved grid.

[0038] Alternatively or additionally, measuring segments can also be or form a regular grid, resulting in a subdivision into axially parallel, rectangular areas.

[0039] Alternatively, measuring segments can also be arranged in an irregular grid. For high spatial resolution, preferably at least one of the following is provided: adjacent measuring segments have a boundary; adjacent measuring segments of at least the first plate have a boundary that is at least partially a recess; adjacent measuring segments of at least the second plate have a boundary that is at least partially a recess; a recess is or forms a depression, in particular a groove, extending from a first side of at least the first plate towards a second side of at least the first plate opposite the first side; a recess is or forms a depression, in particular a groove, extending from a first side of at least the second plate towards a second side of at least the second plate opposite the first side.The first side of at least the first plate is associated with an outer surface of at least the first plate; the first side of at least the second plate is associated with an outer surface of at least the second plate; recesses have a depth of at most 80%, in particular at most 70%, in particular at most 60%, based on the thickness of at least the first plate and / or based on the thickness of at least the second plate.

[0040] This allows for a physical subdivision of measurement segments.

[0041] The measuring segments are electrically connected to one another. Cutouts reduce the electrical conductor cross-section between adjacent measuring segments, thereby increasing transverse resistance and reducing transverse currents. This contributes to a more precise spatial delineation and allocation of measured values ​​to their respective segments.

[0042] Recesses are, for example, depressions, especially closed depressions, particularly grooves.

[0043] Preferably, recesses on the outside are assigned to at least the first plate and / or at least the second plate, so that in particular contact surfaces are physically subdivided and a particularly high spatial resolution is enabled.

[0044] It has been found that a good balance between the stability of at least the first plate and / or at least the second plate and the measurement quality is achieved when the depth of the depressions is preferably at most 80%, in particular at most 70%, and in particular at most 60% of the thickness of at least the first plate and / or at least the second plate.

[0045] Recesses, especially depressions, are created, for example, by milling, laser cutting, and / or etching. For ease of design, at least one of the following is advantageous:

[0046] Cutouts are or form a structured grid;

[0047] The cutouts are or form a regular grid;

[0048] The cutouts are arranged radially around a central point;

[0049] The cutouts are arranged symmetrically around a central point.

[0050] For example, cutouts are or form a structured and / or regular grid.

[0051] An arrangement in a structured grid means, in particular, that a grid of recesses has a regular topology. For example, it could be an arrangement in a curved grid.

[0052] Alternatively or additionally, cutouts can also form a regular grid, resulting in a subdivision into axially parallel, rectangular areas.

[0053] Alternatively, cutouts can also be arranged in an irregular grid.

[0054] It is advantageous if at least one of the following is provided: a resistance measuring device is assigned to a measuring segment;

[0055] Resistance measuring devices are each arranged at least approximately at the geometric center of a measuring segment; resistance measuring devices of adjacent measuring segments have a distance of at least 10 mm from each other; predetermined surface areas of at least the first plate are electrically connected to opposite predetermined surface areas of at least the second plate by means of the respective conductor and / or connection device.

[0056] Preferably, a division into predetermined area areas is carried out by assigning a resistance measuring device to an area area, to which in particular a measuring segment is assigned.

[0057] Advantageously, resistance measurement directions are arranged at least approximately at the geometric center of a measurement segment. "At least approximately" means that the resistance measurement directions are arranged exactly at the geometric center or at a small distance from it, where this small distance is at most 10%, and in particular at most 5%, of the maximum geometric extent of a measurement segment.

[0058] In particular, predefined area regions and measurement segments correspond in their respective geometric dimensions.

[0059] It has been found that good resolution and good measurement quality can be achieved when the distance between resistance measuring devices and adjacent measuring segments is at least 10 mm.

[0060] It is advantageous if predefined surface areas of at least the first plate are electrically connected to corresponding predefined surface areas of at least the second plate by means of resistance measuring devices and the respective conductors and / or terminals. Each predefined surface area of ​​at least the first plate is thus assigned a corresponding predefined surface area of ​​at least the second plate. This enables electrical coupling between at least the first plate and at least the second plate, so that, particularly when the measuring device is used within an electrochemical energy converter, for example, a current flow through the measuring device is enabled and measured there.

[0061] For high measurement accuracy and a wide range of applications, it is advantageous if at least one of the following is provided:

[0062] Resistance measuring devices each have an electrical resistance of at least 0.01 pQ, in particular at least 0.1 pQ, in particular at least 1 pQ, in particular at least 10 pQ, in particular at least 20 pQ;

[0063] Resistance measuring devices each have an electrical resistance of at most 100 Q, in particular at most 50 Q, in particular at most 20 Q, in particular at most 10 Q, in particular at most 5 Q, in particular at most 1 Q, in particular at most 500 mQ, in particular at most 100 mQ, in particular at most 50 mQ, in particular at most 20 mQ, in particular at most 10 mQ, in particular at most 5 mQ, in particular at most 2 mQ.

[0064] It is advantageous if resistance measuring devices are arranged at least approximately geometrically parallel to each other, with respect to a direction transverse, and in particular normal, to a plate plane of at least the first plate and / or the second plate.

[0065] This enables simple manufacturing and assembly. It has been found that for high measurement accuracy and high spatial resolution, at least one of the following is advantageous: the measuring device has at least three, in particular at least four, in particular at least five, resistance measuring devices per temperature-sensitive element; the measuring device has at most ten, in particular at most nine, in particular at most eight, in particular at most seven, resistance measuring devices per temperature-sensitive element.

[0066] For a simple design implementation, preferably at least one of the following is provided: the contact surface of at least the first plate and / or the second plate has an area of ​​at least 4 cm². 2 the measuring device has at least four resistance measuring devices; the measuring device has at least four measuring segments.

[0067] This allows the measuring device to be used in electrochemical energy converters of various geometric dimensions. For example, it can be used in both stationary and mobile systems.

[0068] Advantageously, at least the first plate and the second plate each have an outer side and an inner side opposite the outer side with at least one of the following: the inner side of at least the first plate and the inner side of at least the second plate face each other;

[0069] Resistance measuring devices are assigned to the inner surface of at least the first plate and the inner surface of at least the second plate; the inner surface of at least the first plate and / or the inner surface of at least the second plate has a plurality of recesses that are arranged essentially geometrically parallel to each other, extending from the inner surface towards the outer surface, and to each of which a resistance measuring device is assigned; the inner surface of the first plate and / or the inner surface of the second plate has a plurality of recesses that are arranged essentially geometrically parallel to each other, and to each of which a contact element for electrical contacting a conductor and / or a terminal of a resistance measuring device is assigned; the contact surface is assigned to the outer surface;

[0070] Measuring segments extend from the outside of at least the first plate to the outside of at least the second plate.

[0071] Preferably, resistance measuring devices are assigned to the opposing inner surfaces of at least the first and second plates. This ensures, in particular, that the resistance measuring elements are encapsulated between the plates and thus protected against external influences, such as surrounding process media and / or contaminants, and against wear. Recesses, especially geometrically parallel recesses, on the inner surface of the first and / or second plate facilitate easy mounting, placement, and alignment of individual resistance measuring devices.

[0072] In recesses, contact elements, for example made of a copper material, are arranged in particular for the electrical contacting of a conductor device and / or a connection device of a resistance measuring device.

[0073] For example, during manufacturing, conductors and / or connection devices can be welded to the inner surface of at least the first plate, thus establishing an electrical connection. On the opposite inner surface of at least the second plate, contact elements, particularly those arranged in recesses, facilitate simple electrical contact with at least the second plate.

[0074] In particular, measuring segments extend from the outside of at least the first plate to the outside of at least the second plate, and thus especially in the thickness direction of the measuring device, so that good electrical conductivity is achieved in the thickness direction.

[0075] In an advantageous embodiment of the invention, at least one of the following is provided: at least the first plate and the second plate have a specific resistance of at most 5 mm. 2 / m on; at least the first plate and the second plate are made of the same material; at least the first plate and the second plate are made of the same material as a bipolar plate of the electrochemical energy converter; at least the first plate and the second plate are made of a metal; at least the first plate and the second plate are made of titanium; at least the first plate and the second plate are made of nickel; at least the first plate and the second plate are made of stainless steel; at least the first plate and the second plate are made of graphite.

[0076] This enables good conductivity and high measurement quality while maintaining high chemical resistance.

[0077] For ease of manufacture, it is advantageous if at least one of the following is provided: at least the first plate and the second plate are bonded together by means of a material bond; at least the first plate and the second plate each have an edge region, wherein the edge region of the first plate and the edge region of the second plate are bonded together by means of an adhesive; at least the first plate and the second plate each have a central region enclosed by the edge region, wherein the central region of the first plate and the central region of the second plate are bonded together by means of an adhesive; the adhesive is made of an electrically insulating material; the adhesive is made of a thermally conductive material; the adhesive is or forms a filler;

[0078] Measurement segments are assigned to the central area.

[0079] Firstly, the resistance measuring devices can be encapsulated, so that they are protected from surrounding process media and / or contaminants.

[0080] Furthermore, the material-bonded connection in the central area contributes in particular to the stability of the measuring device.

[0081] Furthermore, the adhesive acts as an electrical insulator within the gap between at least the first and at least the second plates, thus electrically isolating resistance measuring devices within this gap from one another. This minimizes electrical interactions between resistance measuring devices within the gap, contributing to high measurement accuracy.

[0082] For easy implementation and integration into the electrochemical energy converter, it is advantageous if the adhesive is made of a thermally conductive material. Integrating the electrochemical measuring device into an electrochemical energy converter is also straightforward if the electrochemical measuring device has high thermal conductivity.

[0083] Advantageously, at least one of the following is provided: the measuring device has a circular contour; the measuring device has a rectangular, in particular square, contour.

[0084] This enables the use of the measuring device in electrochemical energy converters with various geometric designs.

[0085] For a compact design, it is advantageous if at least one of the following is provided: a thickness of at least the first plate is at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm; a thickness of at least the second plate is at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm; a thickness of the measuring device is at least 0.5 mm, in particular at least 1 mm, in particular at least 2 mm.

[0086] For example, a compact design allows for easy integration of the measuring device into existing systems, especially electrochemical energy converters.

[0087] As mentioned at the outset, the invention relates to an electrochemical energy converter, in particular an electrolysis cell, in particular an electrolysis stack, in particular a hydrogen-oxygen electrolysis cell, in particular a fuel cell, in particular a fuel cell stack, in particular a hydrogen-oxygen fuel cell, comprising a housing, at least one electrochemical functional unit, in particular at least one bipolar plate and / or at least one electrode and / or one end plate and / or at least one porous transport layer (PTL) and / or at least one catalyst-coated membrane (CCM) and / or at least one gas diffusion layer (GDL), and at least one measuring device according to the invention.

[0088] The electrochemical energy converter has the advantages already explained in connection with the measuring device according to the invention.

[0089] It is advantageous if at least one of the following is provided: the measuring device includes a bipolar plate; at least the first plate of the measuring device is or forms a bipolar plate; at least the second plate of the measuring device is or forms a bipolar plate.

[0090] This allows for a compact design of the electrochemical energy converter, in particular an electrolysis cell and / or an electrolysis stack and / or a fuel cell and / or a fuel cell stack.

[0091] Within an electrolysis stack and / or fuel cell stack, which preferably comprises several electrochemical cells with at least one bipolar plate, wherein the electrochemical cells are arranged sequentially and electrically connected in series, one or more bipolar plates can be replaced by measuring devices. This allows for the simple monitoring of the local activity of the chemical reaction in the electrochemical energy converter.

[0092] It is also possible to integrate measuring devices into an electrochemical energy converter. For a simple design, it is advantageous to provide at least one of the following: at least the first and second plates of the measuring device are made of the same material as the bipolar plate; at least the first and second plates of the measuring device are made of the same material as the housing.

[0093] Furthermore, this can minimize the impact on the electrochemical process.

[0094] For efficient operation, it is advantageous if at least one of the following is provided:

[0095] - the electrochemical energy converter operates at an operating pressure of at least 1 bar, in particular at least 10 bar, in particular at least 20 bar, in particular at least 25 bar;

[0096] - the electrochemical energy converter operates at a pressure of a supplied operating medium, in particular fuel, of at least 1 bar, in particular at least 10 bar, in particular at least 20 bar, in particular at least 25 bar;

[0097] - The electrochemical energy converter operates at an operating pressure of no more than 700 bar, in particular no more than 500 bar, in particular no more than 200 bar, in particular no more than 100 bar, in particular no more than 60 bar; - The electrochemical energy converter operates at a pressure of a supplied operating medium, in particular fuel, of no more than 700 bar, in particular no more than 500 bar, in particular no more than 200 bar, in particular no more than 100 bar, in particular no more than 60 bar.

[0098] The operating medium, in particular fuel, can be, for example, water and / or hydrogen and / or oxygen and / or ambient air and / or nitrogen.

[0099] The operating pressure is, for example, the total system pressure at which the electrochemical energy converter is operated.

[0100] As mentioned at the outset, the invention relates to a method for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter, with a measuring device according to the invention, wherein the method comprises a segment-wise division of at least a first plate and a second plate of the measuring device into predetermined surface areas, wherein each predetermined surface area is or is assigned a measuring segment, wherein each measuring segment is or is assigned at least one resistance measuring device and / or at most one temperature-sensitive element, and wherein at least the first plate and the second plate have a contact surface which is provided for electrical contacting at least one electrochemical functional unit of the electrochemical energy converter.wherein the conductors and / or connection devices of resistance measuring devices are electrically connected to the respective contact surface.

[0101] The method according to the invention has the advantages already explained in connection with the measuring device and the electrochemical energy converter according to the invention. The following description of preferred embodiments, in conjunction with the drawings, serves to explain the invention in more detail.

[0102] They show:

[0103] Figure 1: a top view of an embodiment of a measuring device according to the invention;

[0104] Figure 2: a sectional view of the measuring device along line 2-2 from Figure 1;

[0105] Figure 3: a top view of the measuring device from Figure 1, with a second plate hidden;

[0106] Figure 4: a perspective view of an embodiment of an electrochemical energy converter according to the invention, wherein a first housing part of the electrochemical energy converter is hidden, so that an installation situation of the measuring device from Figure 1 is recognizable;

[0107] Figure 5: an exploded view of an embodiment of an electrochemical energy converter according to the invention with the measuring device from Figure 1;

[0108] Figure 6: a sectional view of the electrochemical energy converter from Figure 5;

[0109] Figure 7: an exploded view of a further embodiment of an electrochemical energy converter according to the invention with the measuring device from Figure 1; Figure 8: a sectional view of the electrochemical energy converter from Figure 7;

[0110] Figure 9: a top view of a further embodiment of the measuring device according to the invention;

[0111] Figure 10: a sectional view of the measuring device along line 10-10 from Figure 9;

[0112] Figure 11: a perspective view of the electrochemical energy converter according to Figure 4, wherein a first housing part of the electrochemical energy converter is hidden, so that an installation situation of the measuring device from Figure 9 is recognizable;

[0113] Figure 12: a sectional view of the electrochemical energy converter from Figure 11.

[0114] An embodiment of a measuring device according to the invention is shown schematically in Figures 1 to 3 and is labelled there with reference numeral 10.

[0115] Furthermore, an embodiment of an electrochemical energy converter according to the invention is schematically shown in Figures 4 to 6 and is labelled there with reference numeral 12.

[0116] The same reference symbols are used below for identical or similar components.

[0117] The measuring device 10 is electrically connected to the measuring device (also not shown) by means of conductors that are not shown in the drawing for the sake of clarity. The measuring device 10 comprises a plurality of resistance measuring devices 14, temperature-sensitive elements 16, a first plate 18 and a second plate 20.

[0118] Furthermore, the measuring device 10 has a plurality of measuring segments 21.

[0119] The first plate 18 and the second plate 20 are joined together by material bonding and are in particular spaced apart, and in particular arranged parallel to each other.

[0120] Resistance measuring devices 14 and temperature-sensitive elements 16 are arranged between the first plate 18 and the second plate 20.

[0121] For example, the measuring device 10 has at least three, in particular at least four, in particular at least five, resistance measuring devices 14 per temperature-sensitive element 16.

[0122] For example, the measuring device 10 has at most ten, in particular at most nine, in particular at most eight, in particular at most seven, resistance measuring devices 14 per temperature-sensitive element 16.

[0123] Resistance measuring devices 14 each have, in particular, an electrical resistance of at least 0.01 pQ, in particular at least 0.1 pQ, in particular at least 1 pQ, in particular at least 10 pQ, in particular at least 20 pQ.

[0124] Resistance measuring devices 14 each have, in particular, an electrical resistance of at most 100 Q, in particular at most 50 Q, in particular at most 20 Q, in particular at most 10, in particular at most 5 Q, in particular at most 1 Q, in particular at most 500 mQ, in particular at most 100 mQ, in particular at most 50 mQ, in particular at most 20 mQ, in particular at most 10 mQ, in particular at most 5 mQ, in particular at most 2 mQ.

[0125] Resistance measuring devices 14 each comprise at least one resistance element 22 and a conductor device 24 and / or a connection device 26.

[0126] Conducting devices 24 and / or connection devices 26 are provided for electrical contacting the plates 18, 20.

[0127] Resistance measuring devices 14 are intended for measuring various quantities, for example, current and / or voltage and / or temperature.

[0128] The first plate 18 and the second plate 20 are preferably made of an electrically conductive material, for example titanium and / or nickel and / or stainless steel and / or graphite. The resistivity of the plates 18 and 20 is, in particular, at most 5 mm². 2 / m.

[0129] The first plate 18 and the second plate 20 each have a partially circular contour 28, with a tab 32 arranged on opposite sections 30 for easier assembly. The tabs 32 are preferably integrally connected to the plates 18 and 20.

[0130] The first plate 18 and the second plate 20 alternatively have a rectangular contour 28, in particular a square contour 28.

[0131] Furthermore, the first plate 18 and the second plate 20 each have a first side 34 and a second side 36 opposite the first side 34, as well as an outer side 38 and an inner side 40 opposite the outer side 38. The first side 34 is assigned to the outer side 38. The second side 36 is assigned to the inner side 40.

[0132] A thickness t of the plates 18, 20 extends from the first side 34 to the second side 36 or from the outside 38 to the inside 40. The thickness t of the first plate 18 and / or the second plate 20 is in particular at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm.

[0133] The thickness T of the measuring device is in particular at least 0.5 mm, in particular at least 1 mm, in particular at least 2 mm.

[0134] The first side 34 and / or the second side 36 and / or the outer side 38 and / or the inner side 40 are in particular aligned parallel to a plate plane 42 and / or define the plate plane 42. The thickness t extends in a direction transverse, and in particular perpendicular, to the plate plane 42.

[0135] The inner surface 40 of the first plate 18 and the inner surface 40 of the second plate 20 face each other. Therefore, the outer surfaces 38 of the plates 18 and 20 are also, in particular, the outer surfaces of the measuring device 10.

[0136] Resistance measuring devices 14 and / or temperature-sensitive elements 16 are each assigned to the inner sides 40 of the plates 18, 20.

[0137] Conducting devices 24 and / or connection devices 26 of resistance measuring devices 14 are, for example, electrically connected to the first plate 18 by means of a welded connection.

[0138] The inner surface 40 of the second plate 20 has a plurality of recesses 41, each extending from the inner surface 40 towards the outer surface 38. In particular, the recesses 41 are arranged geometrically parallel to each other.

[0139] Each recess 41 is assigned a resistance measuring device 14.

[0140] The conductors 24 and / or connection devices 26 of resistance measuring devices 14 are electrically connected to the second plate 20 by means of contact elements 43 arranged in the recesses.

[0141] Contact elements 43 are made in particular of a copper material.

[0142] The first plate 18 and the second plate 20 each have a contact surface 44, in particular a closed one, for electrically contacting at least one electrochemical functional unit 46 of the electrochemical energy converter 12. The electrochemical functional unit 46 is in particular a bipolar plate 48 and / or an electrode arrangement 50 and / or an electrode and / or an end plate and / or a porous transport layer (PTL) and / or a catalyst-coated membrane (CCM) and / or a gas diffusion layer (GDL). The contact surface 44 is associated with the first side 34 or the outer side 38.

[0143] Resistance measuring directions 14 or a selection of resistance measuring directions 14 are electrically connected to the contact surfaces 44 by means of the respective conducting device 24 and / or connection device 26.

[0144] The first plate 18 and the second plate 20 each have a border region 52 and a central region 54. The central region 54 is enclosed by the border region 52. In particular, the border region 52 completely surrounds the central region 54. Measuring segments 21 are specifically assigned to the respective central regions 54 of plates 18 and 20.

[0145] Each of the central areas 54 is specifically assigned resistance measuring devices 14.

[0146] The edge regions 52 of the first plate 18 and the second plate 20 are bonded together by means of an adhesive 56. The adhesive 58 is in particular made of an electrically insulating material and / or a thermally conductive material.

[0147] The central areas 54 of the plates 18, 20 are bonded together by means of an adhesive 58. The adhesive 58 is in particular made of an electrically insulating material and / or a thermally conductive material.

[0148] The adhesive 56, 58 is or forms, for example, a filler 60 that fills a space 62 between the first plate 18 and the second plate 20 and thus contributes to the stability of the measuring device 10.

[0149] Furthermore, measuring segments 21 are each electrically conductively connected to the respective contact surfaces 44 of the plates 18, 20.

[0150] Measuring segments 21 each extend from the first side 34 of the first plate 18 to the first side 34 of the second plate 20 or from the outside 38 of the first plate 18 to the outside 38 of the second plate 20, i.e. in particular over the entire thickness T of the measuring device 10.

[0151] A measuring segment 21 is associated with a resistance measuring device 14 and / or a temperature-sensitive element 16. Measuring segments 21 are spaced apart from each other and each has a geometric center 66.

[0152] Adjacent measuring segments 21 have a distance d between their geometric centers. The distance d is, for example, at least 10 mm.

[0153] Resistance measuring elements 14 are each arranged at least approximately at the geometric center of a measuring segment 21.

[0154] For example, measuring segments 21 are arranged in a structured grid. An arrangement in a structured grid means, in particular, that a grid of measuring segments 21 has a regular topology. For example, it could be an arrangement in a curved grid.

[0155] Alternatively or additionally, measuring segments 21 can also be arranged in a regular grid, so that a subdivision into axially parallel, rectangular areas is made.

[0156] Measurement segments 21 have at least approximately the same area. "At least approximately" means that the areas of the measurement segments differ from each other by a maximum of 10%, and in particular by a maximum of 5%.

[0157] Furthermore, the first plate 18 and the second plate 20 are or will be divided into predefined surface areas 64, with a measuring segment 21 being assigned to a predefined surface area 64. This results in a spatial division of the plates 18 and 20 into predefined surface areas 64 and an allocation of measuring segments 21 to predefined surface areas 64. In particular, exactly one measuring segment 21 is assigned to exactly one predefined surface area 64. Predefined surface areas 64 of the first plate 18 are electrically connected to opposite predefined surface areas 64 of the second plate 20 by means of resistance measuring devices 14 via the respective connecting device 24 and / or connection device 26. Thus, each predefined surface area 64 of the first plate 18 is specifically assigned to a corresponding opposite predefined surface area 64 of the second plate 20.This enables electrical coupling of the first plate 18 with the second plate 20, so that, in particular when using the measuring device 10 within the electrochemical energy converter 12, for example, a current flow through the measuring device 10 is enabled and measured there.

[0158] The current flows in a direction 65 transversely, in particular perpendicularly, to the plate planes 42 of the respective plates 18, 20.

[0159] Furthermore, measuring segments 21 have boundaries 68. Boundaries 68 of measuring segments correspond in particular to boundaries 69 of predefined area areas 64.

[0160] The boundaries 68 of the individual measuring segments 21 and the boundaries 69 of surface areas 64 are shown with dashed lines in Figure 1. These boundaries 68 are primarily virtual and are not physically realized on the respective plates 18, 20.

[0161] Boundaries 68, 69 result in particular from the assignment of resistance measuring devices 14 to measuring segments 21. An assignment of individual resistance measuring devices 14 to measuring segments 21 results in particular from the shortest electrical lead length of a resistance measuring device 14 to the contact surface 44. Boundaries 68, 69 are in particular a set of equidistant points between resistance measuring devices 14 of adjacent measuring segments 21. Due to the spatial division of the plates 18, 20 into predefined surface areas 64 described above and the assignment of measuring segments 21 to surface areas 64, it is thus possible to acquire a measured value in each measuring segment 21. A spatial resolution of measured values, each assigned to a measuring segment 21, results via the contact surface 44.This means that it is possible to represent the local activity of the chemical reaction in the electrochemical energy converter based on the measured values ​​and to assign individual measured values ​​to a measurement segment 21.

[0162] The electrochemical energy converter 12 is in particular an electrolysis cell and / or fuel cell, and in particular a hydrogen-oxygen electrolysis cell and / or hydrogen-oxygen fuel cell.

[0163] Operating fluid, in particular fuel, can be supplied to the electrochemical energy converter 12 by means of a supply device (not shown in the drawing for clarity). Water and / or hydrogen and / or oxygen and / or ambient air and / or nitrogen, for example, can be used.

[0164] The electrochemical energy converter 12 is operated in particular at an operating pressure and / or pressure of the supplied operating fluid of in particular at least 1 bar, in particular at least 10 bar, in particular at least 20 bar, in particular at least 25 bar.

[0165] Alternatively or additionally, the electrochemical energy converter 12 can be operated at an operating pressure and / or pressure of the supplied operating fluid of, in particular, not more than 700 bar, in particular not more than 500 bar, in particular not more than 200 bar, in particular not more than 100 bar, in particular not more than 60 bar. The electrochemical energy converter includes the measuring device 10, which is integrated into it for measuring the current distribution and / or the heat distribution.

[0166] Furthermore, the electrochemical energy converter 12, as explained above, comprises an electrochemical functional unit 46. The electrochemical functional unit 46 is, in particular, a bipolar plate 48 and / or an electrode arrangement 50 and / or an electrode. The electrochemical functional unit 46 is provided for electrical contact by means of at least one contact surface 44 of the plates 18, 20.

[0167] The electrode arrangement 50 is, for example, a membrane electrode arrangement 80 with a gas diffusion layer 82 arranged on both sides of the membrane electrode arrangement and an intermediate layer 84.

[0168] The measuring device 10 includes and / or acts as a bipolar plate 48. It is therefore possible to replace a bipolar plate 48 of the electrochemical energy converter 12 with a measuring device 10, so that the functions of the bipolar plate 48 are integrated into the measuring device 10.

[0169] Alternatively, it is also possible to integrate the measuring device 10 additionally into the electrochemical energy converter 12.

[0170] The electrochemical energy converter 12 further comprises a housing 72 with a first housing part 74 and a second housing part 76.

[0171] It is intended that the first and second housing parts 74, 76 are mechanically connected to each other by means of connecting elements 78.

[0172] Electrochemical functional units 46 are located between the first housing part

[0173] 74 and the second housing part 76 are arranged. It is intended that housing parts 74, 76 act as electrochemical functional units 46.

[0174] The material of the first plate 18 and the second plate 20 of the measuring device is, for example, the same as the material of the bipolar plate 48 and / or the housing parts 74, 76.

[0175] Another embodiment of an electrochemical energy converter according to the invention is shown schematically in Figures 7 and 8 and is designated there by the reference numeral 12'.

[0176] The electrochemical energy converter 12' is largely identical in structure to the electrochemical energy converter 12. The electrochemical energy converter 12' is in particular an electrolysis stack and / or a fuel cell stack, which is composed of several electrolysis cells and / or fuel cells connected in series with the components described above.

[0177] Another embodiment of a measuring device according to the invention is shown schematically in Figures 9 and 10 and is labelled there with the reference numeral 10'.

[0178] Furthermore, in Figures 11 and 12, another embodiment of an electrochemical energy converter according to the invention is shown schematically and is designated there by the reference numeral 12", wherein the electrochemical energy converter 12" corresponds to the electrochemical energy converter 12 with the exception that the electrochemical energy converter 12" comprises the measuring device 10'.

[0179] The measuring device 10' is constructed identically to the measuring device 10 with the difference that boundaries 68, 69 of measuring segments 21 and / or predefined surface areas 64 are or form recesses 90.

[0180] Recesses 90 are or form depressions 92, in particular grooves, and extend from the outside 38 towards the inside 40 or from the first side 34 towards the second side 36 of the respective plates 18, 20.

[0181] Recesses 90 are assigned to the outside 38 or the first side 34.

[0182] In the present embodiment of the measuring device 10', the first plate 18 has recesses 90 on its outer side 38 or first side 34.

[0183] However, it is also possible that only the second plate 20 has 38 recesses on its outer side or 34 recesses on its first side.

[0184] Alternatively, it is also possible that both plates 18, 20 have 38 or 34 recesses 90 on their respective outer sides or first sides.

[0185] Recesses 92 of openings 90 have a depth s which, in relation to the respective thickness d of the plates, is in particular at most 80%, in particular at most 70%, in particular at most 60%.

[0186] This allows for a physical subdivision of measurement segments 21 and / or predefined area areas 64.

[0187] The cutouts 90 reduce the electrical conductor cross-section between adjacent measuring segments 21, thereby increasing transverse resistances between adjacent measuring segments 21 and reducing transverse currents. This contributes to a good spatial delimitation and assignment of measured values ​​to measuring segments 21.

[0188] Cutouts 90 are, or form, for example, a structured grid. An arrangement in a structured grid means, in particular, that a grid of cutouts has a regular topology. For example, it could be an arrangement in a curved grid.

[0189] Alternatively or additionally, cutouts 90 can also be or form a regular grid, so that a subdivision into axially parallel, rectangular areas is achieved.

[0190] In the inventive method for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter 12; 12'; 12", with a measuring device 10; 10', a segmental division of the first plate 18 and the second plate 20 is carried out. This makes it possible, in particular, to define surface areas 64 and to assign measuring segments 21 to the defined surface areas 64.

[0191] Each measuring segment 21 is assigned at least one resistance measuring device 14, in particular exactly one resistance measuring device 14.

[0192] Each measuring segment 21, for example, is assigned at most one temperature-sensitive element 16.

[0193] Conducting devices 24 and / or connection devices 26 are electrically connected to the respective contact surface 44 of the first plate 18 and the second plate 20.

[0194] This makes it possible to determine a measured value for each measurement segment 21, thus enabling the assignment of individual measured values ​​to measurement segments 21. This allows for local, spatial resolution, so that, for example, a current distribution and / or current density distribution and / or heat distribution can be displayed with local resolution.

[0195] Reference symbol list d Distance s Depth t Thickness T Thickness 10 Measuring device 10' Measuring device 12 Electrochemical energy converter 12' Electrochemical energy converter 12" Electrochemical energy converter 14 Resistance measuring device 16 Temperature-sensitive element 18 First plate 20 Second plate 21 Measuring segment 22 Resistance element 24 Conducting device 26 Connection device 28 Contour 30 Section 32 Tab 34 First side 36 Second side 38 Outside 40 Inside 41 Recess 42 Plate plane 43 Contact element 44 Contact surface 46 Electrochemical functional unit Bipolar plate

[0196] electrode

[0197] Edge area

[0198] Central area

[0199] adhesive

[0200] adhesive

[0201] filler

[0202] space

[0203] Area

[0204] Current flow direction, geometric center, boundary

[0205] Boundary

[0206] Housing first housing part second housing part

[0207] Connecting element

[0208] Membrane electrode array, gas diffusion layer, intermediate layer

[0209] Exclusion

[0210] in-depth

Claims

Patent claims 1. Measuring device for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter (12; 12'; 12"), wherein the measuring device (10; 10') comprises a plurality of resistance measuring devices (14), a plurality of measuring segments (21), and at least one first plate (18) made of an electrically conductive material and a second plate (20) made of an electrically conductive material, wherein resistance measuring devices (14) each comprise a conduction device (24) and / or a connection device (26) and at least one resistive element (22), wherein at least the first plate (18) and the second plate (20) each have a contact surface (44) for electrically contacting at least one electrochemical functional unit (46) of the electrochemical energy converter (12; 12';12"), and wherein resistance measuring devices (14) or a selection of resistance measuring devices (14) are electrically connected to the contact surface (44) of at least the first plate (18) and to the contact surface (44) of at least the second plate (20) by means of the respective conducting device (24) and / or connecting device (26) and are arranged between at least the first plate (18) and the second plate (20), and wherein at least the first plate (18) and the second plate (20) are or are divided into predetermined surface areas (64), and wherein measuring segments (21) comprise at least one of the following: a measuring segment (21) is assigned to a predetermined surface area (64); at least one resistance measuring device (14) is assigned to a measuring segment (21); Each measuring segment (21) is assigned at least one temperature-sensitive element (16).

2. Measuring device according to claim 1, characterized by at least one of the following: Measuring segments (21) are arranged at intervals from each other; Measuring segments (21) each have a geometric center (66), wherein adjacent measuring segments (21) have a distance from geometric center (66) to geometric center (66) of at least 10 mm to each other; The measuring segments (21) have at least approximately the same area.

3. Measuring device according to claim 1 or 2, characterized by at least one of the following: Measuring segments (21) are arranged in a structured grid; Measuring segments (21) are arranged in a regular grid; Measuring segments (21) are arranged radially around a center point; Measuring segments (21) are arranged point-symmetrically around a center point.

4. Measuring device according to one of claims 1 to 3, characterized by at least one of the following: adjacent measuring segments (21) have a boundary (68); adjacent measuring segments (21) of at least the first plate (18) have a boundary (68) which is at least partially a recess (90) or forms a recess; adjacent measuring segments (21) of at least the second plate (20) have a boundary (68) which is at least partially a recess (90) or forms a recess (90); a recess (90) is or forms a depression (92), in particular a groove, which extends from a first side (34) of at least the first plate (18) towards a second side (36) of at least the first plate (18) opposite the first side (34);a recess (90) is or forms a depression (92), in particular a groove, which extends from a first side (34) of at least the second plate (20) towards a second side (36) of at least the second plate (20) opposite the first side (34); the first side (34) of at least the first plate (18) is associated with an outer side (38) of at least the first plate (18); the first side (34) of at least the second plate (20) is associated with an outer side (38) of at least the second plate (20); Recesses (92) have a depth of at most 80%, in particular at most 70%, in particular at most 60%, based on the thickness (t) of at least the first plate (18) and / or based on the thickness (t) of at least the second plate (20).

5. Measuring device according to claim 4, characterized by at least one of the following: Cutouts (90) are or form a structured grid; The cutouts (90) are or form a regular grid; The cutouts (90) are arranged radially around a center point; The cutouts (90) are arranged symmetrically around a center point.

6. Measuring device according to one of the preceding claims, characterized by at least one of the following: a resistance measuring device (14) is assigned to a measuring segment (21); Resistance measuring devices (14) are each arranged at least approximately at the geometric center (66) of a measuring segment (21); Resistance measuring devices (14) of adjacent measuring segments (21) have a distance of at least 10 mm from each other; predetermined surface areas (64) of at least the first plate (18) are electrically connected by means of resistance measuring devices (14) to opposite predetermined surface areas (64) of at least the second plate (20) by means of the respective conductor device (24) and / or connection device (26).

7. Measuring device according to one of the preceding claims, characterized by at least one of the following: Resistance measuring devices (14) each have an electrical resistance of at least 0.01 pQ, in particular at least 0.1 pQ, in particular at least 1 pQ, in particular at least 10 pQ, in particular at least 20 pQ; Resistance measuring devices (14) each have an electrical resistance of at most 100 Q, in particular at most 50 Q, in particular at most 20 Q, in particular at most 10 Q, in particular at most 5 Q, in particular at most 1 Q, in particular at most 500 mQ, in particular at most 100 mQ, in particular at most 50 mQ, in particular at most 20 mQ, in particular at most 10 mQ, in particular at most 5 mQ, in particular at most 2 mQ.

8. Measuring device according to one of the preceding claims, characterized in that resistance measuring devices (14) are arranged at least approximately geometrically parallel to each other, with respect to a direction transverse, and in particular normal, to a plate plane (42) of at least the first plate (18) and / or the second plate (20).

9. Measuring device according to one of the preceding claims, characterized by at least one of the following: for each temperature-sensitive element (16) the measuring device (10; 10') has at least three, in particular at least four, in particular at least five, resistance measuring devices (14); for each temperature-sensitive element (16) the measuring device (10; 10') has at most ten, in particular at most nine, in particular at most eight, in particular at most seven, resistance measuring devices (14).

10. Measuring device according to one of the preceding claims, characterized by at least one of the following: the contact surface (44) of at least the first plate (18) and / or the second plate (20) has an area of ​​at least 4 cm² 2 the measuring device (10; 10') has at least four resistance measuring devices (14); the measuring device (10; 10') has at least four measuring segments (21).

11. Measuring device according to one of the preceding claims, characterized in that at least the first plate (18) and the second plate (20) each have an outer surface (38) and an inner surface (40) opposite the outer surface (38) with at least one of the following: the inner side (40) of at least the first plate (18) and the inner side (40) of at least the second plate (20) are facing each other; Resistance measuring devices (14) are assigned to the inner surface (40) of at least the first plate (18) and to the inner surface (40) of at least the second plate (20); the inner surface (40) of at least the first plate (18) and / or the inner surface (40) of at least the second plate (20) has a plurality of recesses (41) which are arranged substantially geometrically parallel to each other, extending from the inner surface (40) towards the outer surface (38), and to each of which a resistance measuring device (14) is assigned; the inner surface (40) of the first plate (18) and / or the inner surface (40) of the second plate (20) has a plurality of recesses (42) which are arranged substantially geometrically parallel to each other, and to each of which a contact element (43) for electrical contacting a conductor (24) and / or a connection device (26) of a resistance measuring device (14) is assigned;the contact surface (44) is assigned to the outside (38); Measuring segments (21) extend from the outside (38) of at least the first plate (18) to the outside (38) of at least the second plate (20).

12. Measuring device according to one of the preceding claims, characterized by at least one of the following: at least the first plate (18) and the second plate (20) have a specific resistance of at most 5 mm 2 / m on; at least the first plate (18) and the second plate (20) are made of the same material; at least the first plate (18) and the second plate (20) are made of the same material as a bipolar plate (48) of the electrochemical energy converter (12; 12'; 12"); at least the first plate (18) and the second plate (20) are made of a metal; at least the first plate (18) and the second plate (20) are made of titanium; at least the first plate (18) and the second plate (20) are made of nickel; at least the first plate (18) and the second plate (20) are made of stainless steel; at least the first plate (18) and the second plate (20) are made of graphite.

13. Measuring device according to one of the preceding claims, characterized by at least one of the following: at least the first plate (18) and the second plate (20) are joined together by a material bond; at least the first plate (18) and the second plate (20) each have an edge region (52), wherein the edge region (52) of the first plate (18) and the edge region (52) of the second plate (20) are joined together by an adhesive (56); at least the first plate (18) and the second plate (20) each have a central region (54) enclosed by the edge region (52), wherein the central region (54) of the first plate (18) and the central region (54) of the second plate (20) are joined together by an adhesive (58); the adhesive (56, 58) is made of an electrically insulating material; the adhesive (56, 58) is made of a thermally conductive material;the adhesive (56, 58) is or forms a filler (60); Measurement segments (21) are assigned to the central area (54).

14. Measuring device according to one of the preceding claims, characterized by at least one of the following: the measuring device (10; 10') has a circular contour; the measuring device (10; 10') has a rectangular, in particular square, contour.

15. Measuring device according to one of the preceding claims, characterized by at least one of the following: a thickness (t) of at least the first plate (18) is at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm; a thickness (t) of at least the second plate (20) is at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm; a thickness (T) of the measuring device (10; 10') is at least 0.5 mm, in particular at least 1 mm, in particular at least 2 mm.

16. Electrochemical energy converter, in particular fuel cell and / or electrolysis cell, in particular hydrogen-oxygen fuel cell and / or hydrogen-oxygen fuel cell, comprising a housing (72), at least one electrochemical functional unit (46), in particular at least one bipolar plate (48) and / or at least one electrode (50), and at least one measuring device (10; 10') according to one of claims 1 to 15.

17. Electrochemical energy converter according to claim 16, characterized by at least one of the following: the measuring device (10; 10') comprises a bipolar plate (48); at least the first plate (18) of the measuring device (10; 10') is or forms a bipolar plate (48); at least the second plate (20) of the measuring device (10; 10') is or forms a bipolar plate (48).

18. Electrochemical energy converter claim 16 or 17, characterized by at least one of the following: at least the first plate (18) and the second plate (20) of the measuring device (10; 10') are made of the same material as the bipolar plate (48); at least the first plate (18) and the second plate (20) of the measuring device (10; 10') are made of the same material as the housing (72).

19. Electrochemical energy converter according to one of claims 16 to 18, characterized by at least one of the following: - the electrochemical energy converter (12; 12'; 12") operates at an operating pressure of at least 1 bar, in particular at least 10 bar, in particular at least 20 bar, in particular at least 25 bar; - the operation of the electrochemical energy converter (12; 12'; 12") takes place at a pressure of a supplied operating medium, in particular fuel, of at least 1 bar, in particular at least 10 bar, in particular at least 20 bar, in particular at least 25 bar; - the operation of the electrochemical energy converter (12; 12'; 12") takes place at an operating pressure of at most 700 bar, in particular at most 500 bar, in particular at most 200 bar, in particular at most 100 bar, in particular at most 60 bar; - the operation of the electrochemical energy converter (12; 12'; 12") takes place at a pressure of a supplied operating material, in particular fuel, of at most 700 bar, in particular at most 500 bar, in particular at most 200 bar, in particular at most 100 bar, in particular at most 60 bar.

20. Method for measuring a local current distribution and / or a local heat distribution in an electrochemical energy converter (12; 12'; 12"), with a measuring device (10; 10') according to any one of claims 1 to 15, wherein the method comprises a segmental division of at least a first plate (18) and a second plate (20) of the measuring device (10; 10') into predetermined surface areas (64), wherein each predetermined surface area (64) is or is assigned a measuring segment (21), wherein each measuring segment (21) is or is assigned at least one resistance measuring device (14) and / or at most one temperature-sensitive element (16), and wherein at least the first plate (18) and the second plate (20) have a contact surface (44) for electrical contacting at least one electrochemical functional unit (46) of the electrochemical energy converter (12; 12';12") is provided, wherein conducting devices (24) and / or connecting devices (26) of resistance measuring devices (14) are electrically connected to the respective contact surface (44). ****

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