Cell voltage measuring device for fuel cells

Abstract

Cell voltage measuring device (1) for measuring an electrical voltage on at least one fuel cell (2) of a stack (3) of fuel cells (2), comprising at least one measuring unit (10) for determining a measured value corresponding to the voltage of at least one fuel cell (2), a first communication unit (11), a second communication unit (12) and a central computing unit (13) which is connected to the measuring unit (10) and the communication units (11, 12) via signal technology, wherein the first communication unit (11) is configured to communicate wirelessly with a central connection partner (4) and to transmit at least one measured value and / or a position of the cell voltage measuring device (1) in the stack (3), and wherein the second communication unit (12) is configured to communicate wirelessly with cell voltage measuring devices (1) immediately adjacent in the stack (3) and / or with termination devices (5, 6) immediately adjacent in the stack (3) and concluding the stack (3) and to determine position determination data from this to determine the position of the cell voltage measuring device (1) in the stack (3).

Description

[0001] The invention relates to a cell voltage measuring device for measuring an electrical voltage at at least one fuel cell of a stack of fuel cells, and to a unit comprising such a cell voltage measuring device and at least one fuel cell. The invention further relates to a fuel cell stack and an electrolysis stack with at least one such cell voltage measuring device or such a unit.

[0002] Fuel cells and, in the functional reversal of fuel cells, electrolysis cells are fundamentally known in the state of the art.

[0003] To increase the relatively small voltage of each fuel cell, several cells are connected in series to form a stack, whereby the terms stack and pile are used synonymously in the following.

[0004] In order to assess the conditions and chemical processes in the individual cells and thus also the condition and chemical processes in the entire stack, it is known in the prior art to provide at least one cell voltage measuring device per stack, which is designed to detect the voltage of at least one cell.

[0005] Accordingly, it may be provided, for example, that each fuel cell has its own cell voltage measuring device.

[0006] It is also known to group the fuel cells into groups of, for example, 5 to 10 fuel cells and to provide a cell voltage measuring device for each group, which records the voltage across the fuel cells of the respective group.

[0007] Regardless of whether the voltage is recorded for each fuel cell or whether the voltages for several fuel cells are recorded together, the electrical voltages must be evaluated and transmitted to a higher-level unit or a communication partner.

[0008] For this purpose, a data connection must be provided between the individual cell voltage measuring devices and the connection partner.

[0009] Insofar as this data connection is physical or wired, this entails, on the one hand, increased wiring effort and corresponding space requirements, and on the other hand, increases the risk of sparking.

[0010] This applies both to the use of parallel wiring and to the use of a bus system.

[0011] Document CN 113130948 A therefore proposes that communication between the cell voltage measuring devices of a stack and the connection partner takes place via radio and thus wirelessly.

[0012] However, it is important that the connection partner or the higher-level unit still needs to know the position of the individual cell voltage measuring devices in the stack in order to be able to assess the condition of the stack based on this information.

[0013] The position of the cell voltage measuring devices in a stack can be understood, for example, as a continuous and ascending numbering from the first cell voltage measuring device of the stack belonging to a first cell to the last cell voltage measuring device of the stack, which belongs to a last cell of the stack.

[0014] In a solution based on a wireless connection, as proposed by CN 113130948 A, the position may be permanently stored in the cell voltage measuring devices or the connection partner, but during maintenance or repair, the positions of the cell voltage measuring devices may change, or old cell voltage measuring devices may be replaced by new cell voltage measuring devices whose position in the stack is initially unknown.

[0015] Accordingly, without extensive manual testing and, if necessary, reprogramming, it cannot be ensured that the higher-level unit or the connection partner knows the correct positions of the cell voltage measuring devices in the stack and is therefore unable to evaluate the various voltages correctly.

[0016] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and providing a cell voltage measuring device which allows correct and reliable transmission to a connection partner and evaluation of the voltages in the connection partner even after an exchange of individual cell voltage measuring devices or a change in the arrangement of the cell voltage measuring devices of a stack.

[0017] This problem is solved by the combination of features according to claim 1 as well as by the combination of features of the dependent claims.

[0018] According to the invention, a cell voltage measuring device for measuring an electrical voltage at at least one fuel cell of a stack of fuel cells or at at least one electrolysis cell of an electrolysis stack is proposed. The cell voltage measuring device comprises at least one measuring unit for determining a measured value corresponding to the voltage of at least one fuel cell, a first communication unit, a second communication unit, and a central processing unit, which is connected to the measuring unit and the communication units via signal transmission. It is understood that the processing unit can be integrated into one of the communication units or the measuring unit.Furthermore, the first communication unit is designed to communicate wirelessly, for example via radio, WLAN or Bluetooth, with a central communication partner and to transmit at least one measured value and / or a position of the cell voltage measuring device in the stack to the communication partner. The measured value and the position can be transmitted independently of each other or together, whereby the transmission of the position can, for example, occur once after the position has been determined, and the transmission of the measured values ​​can occur regularly, i.e., at predetermined intervals. Crucially, the second communication unit is designed to communicate wirelessly with devices immediately adjacent in the stack.The second communication unit communicates with cell voltage measuring devices immediately adjacent to the stack and / or with the terminal devices immediately adjacent to and terminating the stack, and uses this communication to determine position data for the cell voltage measuring device's position within the stack. This communication via the second communication unit is preferably optical. Furthermore, communication via the second communication unit preferably occurs exclusively with the immediately adjacent devices.

[0019] To clarify, bidirectional communication is preferred for both the first and second communication units, meaning that the communication units are designed for both sending and receiving.

[0020] Adjacent cell voltage measuring devices are preferably identical in construction, wherein the termination devices in a simple case can also be, for example, at least one mirror or other reflective and in particular concave surfaces, or the termination devices can have such surfaces, through which the signals transmitted by the second communication unit are reflected back, which is registered by the latter and informs the second communication unit that the cell voltage measuring device is arranged adjacent to the termination device on a particularly specific side and is thus, depending on the side, the first cell voltage measuring device or the last cell voltage measuring device of the stack.

[0021] One advantageous variant provides that the computing unit is designed to determine the position of the cell voltage measuring device in the stack from the position determination data.

[0022] This can be achieved, for example, by receiving the position of the preceding cell voltage measuring device from a cell voltage measuring device ahead in the stack via the second communication unit and incrementing it accordingly, e.g. by the value 1.

[0023] Similarly, this can also be done by receiving the position of the next cell voltage measuring device in the stack via the second communication unit and decrementing it accordingly, e.g. by the value 1.

[0024] If, for example, it is the first cell voltage measuring device in the stack, which is communicated to the cell voltage measuring device by the initial-side termination device, for example by reflection, a predetermined value, preferably stored in the cell voltage measuring device for this case, e.g. 0 or 1, can be assumed as the position.

[0025] As explained, the position can be determined using the position determination data in the processing unit. Alternatively or additionally, however, it can be provided that the position determination data determined via the second communication unit is transmitted via the first communication unit to the communication partner, who can then determine the position based on this data.

[0026] Provided that the cell voltage measuring devices are assigned a known address for communication via the first communication unit, and the cell voltage measuring device is thereby reliably identifiable for the communication partner, the position of the cell voltage measuring device does not necessarily have to be determined or stored within it. It is sufficient if the communication partner can assign a position to the respective cell voltage measuring device. For example, the communication partner knows a designated address for communication via the first communication unit. A position can then be assigned to this address.

[0027] To further reduce wiring effort, the cell voltage measuring device can also be provided with a power supply unit for powering the cell voltage measuring device, which can be electrically connected to the respective associated fuel cell for energy generation. For this purpose, a tap can also be made at the contacts provided for the measuring unit on the cell voltage measuring device or the fuel cell, or at a bipolar plate of the fuel cell.

[0028] A particularly preferred design is one in which the second communication unit has at least one optical transceiver and is designed for optical communication, especially in the infrared range.

[0029] Furthermore, it is particularly preferred that the second communication unit has two optical transceivers which are oriented oppositely to each other with respect to their transmit and receive directions, such that preferably a first transceiver of a cell voltage measuring device arranged in the stack points to a starting side of the stack and a second transceiver of the cell voltage measuring device arranged in the stack points to an end side of the stack.

[0030] In other words, it is preferred that the first transceiver is aligned with a cell voltage measuring device preceding in the stack and / or the initial termination device, and that the second transceiver is aligned with a cell voltage measuring device following in the stack and / or the final termination device.

[0031] Since time-coordinated communication between several cell voltage measuring devices of a stack is advantageous for fast and error-free communication via the first communication unit as well as via the second communication unit, it can further be provided that the first communication unit and / or the second communication unit and / or the computing unit is configured to perform time synchronization of the cell voltage measuring device with other and preferably all cell voltage measuring devices of the stack by means of the wireless communication of the first communication unit and / or the wireless communication of the second communication unit.

[0032] For example, if a corresponding command is received via the first communication unit, a predetermined synchronization signal can be sent via the second communication unit and thereby received by the neighboring cell voltage measuring devices.

[0033] Furthermore, the first communication unit and / or the second communication unit and / or the computing unit can be configured to determine, after time synchronization, a time slot that takes the position into account for preferably regularly recurring communication with the communication partner via the first communication unit.

[0034] As described in the introduction, during maintenance or repair, it may happen that the units containing a cell voltage measuring device—that is, the individual groups of fuel cells or the individual fuel cells, each assigned a cell voltage measuring device—are swapped or that individual units are completely replaced. To enable quick and easy position determination in these cases, an automatic position check can be implemented.

[0035] The second communication unit can be configured to transmit the position or the currently stored position as position determination data to cell voltage measuring devices immediately adjacent in the stack, and / or to receive the positions or the currently stored positions of the adjacent cell voltage measuring devices as position determination data in the stack of immediately adjacent cell voltage measuring devices. The second communication unit and / or the processing unit is configured to check or determine the position or the currently stored position based on the position determination data of adjacent cell voltage measuring devices.

[0036] For example, if the currently stored position has the value 4 and the preceding cell voltage measuring device does not receive the value 3 and the subsequent cell voltage measuring device does not receive the value 5, an error or a faulty arrangement can be immediately inferred and, if necessary, a determination of the position can be triggered.

[0037] To improve and increase the reliability of communication via the second communication unit, it is also preferably provided that the second communication unit has at least one shielding element which corresponds to a connection section of an immediately adjacent device, i.e. cell voltage measuring device and / or termination device, so that, in particular in the case of optical communication, the ingress of stray light or dirt into the transmission path between the devices can be prevented.

[0038] A sensor can also be provided as part of the cell voltage measuring device. This sensor can be, for example, a push button, which can be manually operated and / or is designed to be activated when the cell voltage measuring device and, if applicable, the assembly consisting of the cell and cell voltage measuring device described below are inserted. Accordingly, the command to determine the position using the sensor can be issued manually or, if applicable, automatically upon insertion.

[0039] A further aspect of the invention relates to a unit comprising at least one fuel cell and a cell voltage measuring device according to the invention. It is provided that the cell voltage measuring device is integrally connected to the at least one fuel cell, and that the at least one measuring unit for measuring the voltage is electrically contacted with at least one of the fuel cells.

[0040] This also applies analogously to a unit consisting of at least one electrolysis cell and a cell voltage measuring device according to the invention.

[0041] If bipolar plates are provided as part of the fuel cells or electrolysis cells, the cell voltage measuring device can, for example, be fixed directly to at least one of the bipolar plates of the cell or be integrally connected to it.

[0042] The components, but preferably also the cell voltage measuring device itself, are mechanically coded in such a way that installation is only possible in a predetermined position or orientation, in which the second communication unit of the cell voltage measuring device or its transceiver are aligned as intended and point accordingly to adjacent devices, i.e., immediately adjacent cell voltage measuring devices or termination devices.

[0043] Furthermore, one aspect of the invention relates to a fuel cell stack or an electrolysis stack, or a fuel cell system or an electrolyzer with at least one stack. It is provided that these each comprise a plurality of cells arranged in the stack and a plurality of cell voltage measuring devices according to the invention, or alternatively, a plurality of components according to the invention, the cells of which are arranged together in the stack.

[0044] With regard to a fuel cell system or an electrolyzer, the communication partner with which the cell voltage measuring device communicates via the first communication unit can also be part of the respective system.

[0045] Based on the invention, to determine the position of a cell voltage measuring device or a component according to the invention within a stack of a plurality of fuel cells with a plurality of cell voltage measuring devices, it can be provided that steps are carried out which are preferably performed according to the given sequence: a. Receiving a command to determine the position of the cell voltage measuring device in the stack via the first communication unit or the second communication unit or a sensor, wherein the sensor may be, for example, a push button which can be actuated manually or automatically when the fuel cell is mechanically inserted; b. Sending and receiving position data via the second communication unit. c. Determining the position of the cell voltage measuring device from the received position determination data. d. Sending confirmation that the position has been determined, and / or sending the position via the first communication unit.

[0046] The features disclosed above can be combined in any way, provided that this is technically possible and they do not contradict each other.

[0047] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 a system of fuel cell stacks with multiple cell voltage measuring devices and a central connection partner; Fig. 2 a detailed view of a fuel cell stack with several cell voltage measuring devices; Fig. 3 a first variant of a procedure for determining the position; Fig. 4 a second variant of a procedure for determining the position.

[0048] The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features.

[0049] In Fig. Figure 1 shows a fuel cell system consisting of at least one fuel cell stack 3 and a central connection partner 4, which collects and evaluates data from the fuel cells 2 of the stack 3 via a wireless communication link.

[0050] The stack 3 consists of a plurality of fuel cells 2, which are grouped in the present example into groups of four fuel cells 2 each, with each group being assigned a cell voltage measuring device 1, which forms an integral assembly 7 with the respective four fuel cells 2.

[0051] Accordingly, the construction units 7 or the fuel cells 2 of the construction units 7 are arranged together to form the stack 3, which has a first or initial end device 5 on a first end face and a second or end device 6 on an opposite second end face.

[0052] For clarification, it should be noted that a stack 3 can comprise more or fewer groups of fuel cells 2 as well as more or fewer fuel cells 2, and a cell voltage measuring device 1 can also be assigned to more or fewer fuel cells 2.

[0053] At least one, but preferably each, of the cell voltage measuring devices 1 has a measuring unit 10 for determining or measuring a measured value corresponding to the voltage of the associated fuel cells 2, a first communication unit 11 for wireless communication with the communication partner 4, as well as a second communication unit 12 and a central processing unit 13. Preferably, all cell voltage measuring devices 1 of the stack 3 are identical.

[0054] If the order of the components 7 of the stack 3 is changed during maintenance or repair, or if a defective component 7 is replaced by a new component 7, the connection partner 4, as well as the components 7 and their cell voltage measuring devices 1, no longer know the correct position in terms of the order of all cell voltage measuring devices 1 in the stack 3.

[0055] Therefore, it is provided that the second communication unit 12 is designed to communicate wirelessly, and specifically optically in the infrared range, with devices immediately adjacent in the stack 3, i.e., with immediately adjacent cell voltage measuring devices 1 and with closing devices 5, 6 immediately adjacent in the stack 3 and concluding the stack 3, and to determine position determination data from this to determine the position of the cell voltage measuring device 1 in the stack 3.

[0056] This allows the position of individual cell voltage measuring devices 1 or all cell voltage measuring devices 1 of the stack 3 to be checked or redefined automatically in certain situations or by manual command.

[0057] In Fig. 2 is an example of a detailed view of the embodiment according to Fig. 1 shown, so that the Fig. 1. The analogous description applies.

[0058] In addition, the second communication unit 12 or the second communication units 12 are further detailed in that, according to the variant shown, they each have two optical transceivers 121, 122, of which a first optical transceiver 121 is aligned to the cell voltage measuring device 1 preceding in the stack 3 or to the initial termination device 5, and of which a second optical transceiver 122 is aligned to the cell voltage measuring device 1 following in the stack 3 or to the final termination device 6.

[0059] Each transceiver 121, 122 accordingly has a receiver for receiving optical signals and a transmitter for sending optical signals, as illustrated by the arrows extending between the transceivers 121, 122 of adjacent devices.

[0060] To provide feedback on the position of the first cell voltage measuring device 1 or its initial transceiver 121, a mirror 51 is also provided as part of the first or initial termination device 5. Alternatively, the termination device 5 can itself have a transceiver which, upon receiving an input signal, sends back a predetermined output signal or the input signal.

[0061] Further are in Fig. 2 also between the first cell voltage measuring device 1 from the starting side and the subsequent second cell voltage measuring device 1, shielding elements 123 and connection sections 124 are shown, which correspond to each other and protect a respective transmission path, i.e. a first channel from the second transceiver 122 of the first cell voltage measuring device 1 to the first transceiver 121 of the subsequent second cell voltage measuring device 1, as well as a second channel from the first transceiver 121 of the second cell voltage measuring device 1 to the second transceiver 122 of the preceding first cell voltage measuring device 1, from stray light and contamination that may interfere with the communication.

[0062] Such shielding elements 123 and connecting sections 124 can be provided on all transceivers 121, 122 or cell voltage measuring devices 1.

[0063] The Fig. 3 and Fig. Figure 4 illustrates a variant of a procedure for determining the position or for triggering the determination of the position, wherein each of the cell voltage measuring devices 1 according to the Fig. 1 and Fig. 2. Can be trained to perform one or both of the variants.

[0064] In relation to Fig. The following steps are shown in the diagram below, based on a flowchart: A Normal state / Start B. A cyclical or event-based query to check if a manually triggered command for position determination exists. If yes, proceed to step D; if no, proceed to step A. D Determination of the position of the respective cell voltage measuring device 1 by communication via the second communication unit 12 and storage in the computing unit 13 of the respective cell voltage measuring device 1 and / or transmission of the position via the first communication unit 11 to the communication partner. Step E checks whether the position was determined within a predetermined time interval (timeout). If yes, proceed to step A; if no, proceed to step F. F Transmitting an error message via the first communication unit 11 to the connection partner.

[0065] The command requested in step B can be generated, for example, via one of the communication devices 11, 12, or a sensor not shown. Accordingly, the command can be triggered locally at the cell voltage measuring device 1 or centrally by the communication partner 4.

[0066] In relation to Fig. The four steps are essentially the same as in a flowchart. Fig. 3 is shown, although the process differs with regard to the following steps: B. Cyclic or event-based query to determine whether a position determination command has been received via the first communication unit 11. If yes, proceed to step D, and if no, proceed to step C. C. Cyclic or event-based query to determine whether a position determination command has been received via the second communication unit 12. If yes, proceed to step D; if no, proceed to step A. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 113130948 A [0011, 0014]

Claims

[1] Cell voltage measuring device (1) for measuring an electrical voltage on at least one fuel cell (2) of a stack (3) of fuel cells (2), comprising at least one measuring unit (10) for determining a measured value corresponding to the voltage of at least one fuel cell (2), a first communication unit (11), a second communication unit (12) and a central processing unit (13) which is connected to the measuring unit (10) and the communication units (11, 12) by signal technology, wherein the first communication unit (11) is designed to communicate wirelessly with a central connection partner (4) and to transmit the at least one measured value and / or a position of the cell voltage measuring device (1) in the stack (3), and wherein the second communication unit (12) is designed to communicate wirelessly with cell voltage measuring devices (1) immediately adjacent in the stack (3) and / or with terminating devices (5, 6) immediately adjacent in the stack (3) and terminating the stack (3), and to determine therefrom position determination data for determining the position of the cell voltage measuring device (1) in the stack (3). [2] Cell voltage measuring device according to claim 1, wherein the computing unit (13) is designed to determine the position of the cell voltage measuring device (1) in the stack (3) from the position determination data. [3] Cell voltage measuring device according to claim 1 or 2, further comprising a power supply unit for supplying power to the cell voltage measuring device (1), which can be electrically contacted with the fuel cell (2) for power generation. [4] Cell voltage measuring device according to one of the preceding claims, wherein the second communication unit (12) has at least one optical transceiver (121, 122) and is designed for optical communication, in particular in the infrared range. [5] Cell voltage measuring device according to one of the preceding claims, wherein the first communication unit (11) and / or the second communication unit (12) and / or the computing unit (13) is designed to carry out a time synchronization of the cell voltage measuring device (1) with further cell voltage measuring devices (1) of the stack (3) by means of the wireless communication of the first communication unit (11) and / or the wireless communication of the second communication unit (12). [6] Cell voltage measuring device according to the preceding claim, wherein the first communication unit (11) and / or the second communication unit (12) and / or the computing unit (13) is designed to determine, after the time synchronization, a time slot taking the position into account for communication with the connection partner (4) via the first communication unit (11). [7] Cell voltage measuring device according to one of the preceding claims, wherein the second communication unit (12) is designed to transmit the position of the respective cell voltage measuring device (1) to cell voltage measuring devices (1) immediately adjacent in the stack (3) and to receive position determination data of immediately adjacent cell voltage measuring devices (1) in the stack (3), and wherein the second communication unit (12) and / or the computing unit (13) is designed to determine and / or check the position based on the position determination data of adjacent cell voltage measuring devices (1). [8] A structural unit (7) comprising at least one fuel cell (2) and a cell voltage measuring device (1) according to one of the preceding claims, wherein the cell voltage measuring device (1) is connected to the at least one fuel cell (2) in one piece or in one part and the at least one measuring unit (10) for measuring the voltage is electrically contacted with at least one of the fuel cells (2). [9] Fuel cell stack (3) or electrolysis stack with a plurality of cells (2) arranged to form the stack (3) and a plurality of cell voltage measuring devices (1) according to claims 1 to 7 or with a plurality of structural units (7) according to claim 8, whose fuel cells (2) are arranged together to form the stack (3).

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