Connecting element for electrically contacting separator plates of a fuel cell stack

Abstract

Connecting element (5) for electrically contacting at least one separator plate (3) of a fuel cell stack, comprising • a housing (510), • a contact element (520) arranged in the housing (510) with a contact end (521) for contacting the separator plate (3) and with a connection end (523) for connecting to a further line (7), wherein a positive z-direction is defined from the contact end (521) in the direction of the connection end (523), • a recess (511) in the housing (510), wherein the contact element (520) is inserted in the recess (511), wherein the contact end (521) is arranged on a first side (512) of the recess (511), and wherein the terminal end (523) is arranged on the second side (513) of the recess (511), • wherein the contact element (520) has a positive locking element (524) which is positively locked to the first side (512) of the recess (511) on the housing (510), • wherein the contact element (520) has a detent element (525) which is engaged on the housing (510) and blocks movement of the contact element (520) in the negative z-direction.

Description

[0001] The technology disclosed herein relates to a connecting element for electrically contacting at least one separator plate of a fuel cell stack. The connecting element is, in particular, a component of a connection system for connecting the separator plates to a cell monitoring module. Furthermore, the technology disclosed herein relates to a fuel cell system, preferably in a vehicle, comprising the connection system.

[0002] Cell monitoring systems for fuel cell systems comprise a connection system with a connector for contacting the separator plates (monopolar or bipolar plates) of a fuel cell stack. The connection system also includes appropriate electrical conductors to connect the connector to a cell monitoring module of the system. The cell monitoring module processes and evaluates the signals picked up from the separator plates.

[0003] JP2007265674A relates to a device for measuring the local power generation output of a fuel cell and a method for measuring the local power generation output on the electrode surface of a fuel cell. KR 101491 038B1 relates to a connecting cable mounted on a fuel cell and a connecting cable holder that supports the connecting cable for mounting. EP 2 562 863 A1 relates to a connection device for measuring the cell voltage of a fuel cell. JP2007087858A relates to a connection unit in a stacked fuel cell and, in particular, an embodiment of a voltage monitoring connection of a separator.

[0004] Cell monitoring systems (CVM systems) are known, for example, from WO 2007 102031 A1 and WO 2005 069026 A1. A connecting element for contacting the separator plates is known, for example, from DE 10 2007 003506 B4.

[0005] It is an objective of the technology disclosed herein to reduce or eliminate the disadvantages of previously known solutions. In particular, it is an objective of the technology disclosed herein to provide a connecting element for electrically contacting at least one separator plate of a fuel cell stack, which, with simple manufacturing and assembly, enables a reliable and durable electrical connection to the separator plates. Further objectives arise from the advantageous effects of the technology disclosed herein. The objective(s) is / are achieved by the subject matter of claim 1. The dependent claims represent preferred embodiments.

[0006] The technology disclosed herein relates, among other things, to a fuel cell system with multiple stacked fuel cells. The fuel cell system is intended, for example, for mobile applications such as motor vehicles, in particular for providing energy to at least one drive motor for propelling the vehicle. In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, producing electricity and heat in the process. The fuel cell comprises an anode and a cathode separated by an ion-selective or ion-permeable separator. The anode is supplied with fuel. Preferred fuels are hydrogen, low-molecular-weight alcohols, biofuels, or liquefied natural gas. The cathode is supplied with oxidant. Preferred oxidants are, for example, air, oxygen, and peroxides. The ion-selective separator can be, for example, made of...It may be designed as a proton exchange membrane (PEM). A cation-selective polymer electrolyte membrane is preferably used. Examples of materials for such a membrane are: Nafion®, Flemion®, and Aciplex®.

[0007] A fuel cell system comprises not only the fuel cells themselves but also peripheral system components (BOP components) that can be used during operation. Typically, several fuel cells are combined to form a fuel cell stack.

[0008] The fuel cells of the fuel cell system typically comprise two separator plates. The ion-selective separator of a fuel cell is usually arranged between two separator plates. One separator plate, together with the ion-selective separator, forms the anode. The other separator plate, arranged on the opposite side of the ion-selective separator, together with the ion-selective separator, forms the cathode. Gas channels for fuel and / or oxidizer are preferably provided in the separator plates.

[0009] The separator plates can be designed as monopolar plates and / or as bipolar plates. In other words, a separator plate expediently has two sides, one side forming an anode together with an ion-selective separator, and the other side forming a cathode together with another ion-selective separator of an adjacent fuel cell. Gas diffusion layers (GDLs) are typically provided between the ion-selective separators and the separator plates.

[0010] Furthermore, the technology disclosed herein relates to a cell monitoring system. The cell monitoring system (also known as a cell voltage monitoring system or CVM system), and in particular the cell monitoring module of the system, can be configured to monitor the condition of at least one cell. Typically, it monitors the condition of a large number of fuel cells. In this context, monitoring means that the system can directly or indirectly determine the condition of the monitored cells. Advantageously, this allows for the early detection of degradation or cell failure, enabling appropriate countermeasures to be initiated. This may potentially extend the service life to a certain extent and / or improve the overall cell performance through suitable countermeasures. Advantageously, at least one measured variable can be acquired directly or indirectly. This measured variable can, in particular, be the electrical voltage of the monitored cell.Advantageously, the individual cell voltages of several or all cells, as well as the total voltage, are determined. Preferably, the current flowing through the fuel cell stack is also determined. From the measured voltages, the CVM system can, for example, determine one of the following values: minimum, maximum, and average value of the individual cell voltage. This advantageously allows for the detection of voltage deviations between individual cells or from an average value of the individual cell voltages. Preferably, further individual cell analysis methods are performed, such as impedance calculation (e.g., electrochemical impedance spectroscopy).

[0011] The task of the technology disclosed here is solved by a connecting element for electrically contacting at least one separator plate of a fuel cell stack.

[0012] The connecting element can also be called a connector. In its simplest form, the connecting element is used to connect a separator plate. However, the connecting element is typically designed to be plugged onto multiple separator plates. This allows several separator plates of the fuel cell stack to be connected simultaneously.

[0013] The connecting element comprises a housing. At least one contact element is arranged within the housing. The arrangement and design of the contact element are described in detail below. For the sake of simplicity, reference is generally made to a single contact element. In a preferred embodiment, however, several contact elements are arranged within the housing, all of which are designed and arranged within the housing according to the technology disclosed herein.

[0014] The contact element has a contact end. The contact end is designed for electrical contact with the separator plates. In particular, the contact end has a corresponding opening, for example, a slot. This opening is placed onto the separator plate.

[0015] The opposite end of the contact element is called the terminal end. The terminal end is used to electrically connect the contact element to a connecting conductor. This connecting conductor can, for example, be a circuit board trace or a cable.

[0016] The stacked separator plates each lie in a plane defined by a y-axis and a z-axis. The connecting element is moved along the z-axis to attach or detach the plates. Along an x-axis, the multiple separator plates are stacked side by side. The three axes are perpendicular to each other.

[0017] A positive z-direction, parallel to the z-axis, is defined from the contact end towards the terminal end. The negative z-direction runs in the opposite direction, i.e., from the terminal end towards the contact end.

[0018] The housing has a recess for each contact element. The contact element is inserted into this recess or, during assembly of the connecting element, is inserted into the recess. The contact end is located on one side of the recess. The connecting end is located on the other side, or opposite side, of the recess. The contact element has a fixed or integral positive locking element. This positive locking element is located on the first side of the recess and rests against the housing in a form-fitting manner. In particular, the positive locking element rests against an area of ​​the housing that surrounds the recess.

[0019] The recess in the housing is preferably smaller than the positive locking element. The recess is so "smaller" that the contact element, including the positive locking element, can only be inserted into the recess in the positive z-direction.

[0020] According to the technology disclosed herein, the contact element can be inserted into the recess of the housing in the positive z-direction. The positive locking element is fixed to the contact element and does not need to be mounted or inserted separately. No other means of securing the contact element within the housing to prevent movement in the positive z-direction is required. The recess is designed to be so small that the positive locking element rests against the housing, and consequently, the contact element can only be moved in the positive z-direction up to the point where the positive locking element stops. This is particularly advantageous when pulling the connecting element away from the separator plates, especially when pulling on the contact elements or components connected to the contact elements, such as a terminal board, is involved. Due to the positive locking element, the contact element cannot be pulled out of the housing during this pulling action.

[0021] The contact element has a detent element. The detent element is engaged with the housing and blocks movement of the contact element in the negative z-direction. The detent element is, in particular, a spring-loaded element that is deformed when the contact element is inserted into the housing and, when fully inserted, engages with a corresponding detent lug or recess in the housing.

[0022] The locking element primarily serves to prevent the contact element from falling out of the housing during assembly of the connecting element. As will be described in more detail later, the terminal end of the contact element is preferably permanently connected to the connecting line, particularly to a terminal board, on the other side of the recess. This connection also prevents movement of the contact element in the negative z-direction relative to the housing, generally much more reliably than the locking connection.

[0023] The locking element is preferably arranged on the first side of the recess. Sufficient installation space is available on the first side of the recess. Alternatively, the locking element can also be arranged within the recess. Furthermore, it is preferred that the locking element be arranged on the second side of the recess if sufficient installation space is available between the housing and the circuit board.

[0024] In a preferred embodiment, the contact element has a base body made of sheet metal. This sheet metal serves as an electrical conductor, and the contact end and the terminal end are formed from the sheet metal.

[0025] Preferably, the locking element is a tongue bent out of the sheet metal. When the contact element is inserted into the housing, the tongue is first deformed by contact with the housing and then locks into place at the corresponding position.

[0026] The positive locking element, preferably made of plastic, is advantageously attached to the sheet metal. For this purpose, the positive locking element can, for example, be inserted into the sheet metal or injection-molded onto it. In an alternative preferred embodiment, the positive locking element is also formed by appropriately shaping the sheet metal.

[0027] In a preferred embodiment, the connecting conductor includes a terminal board. The terminal board is located in or on the housing, specifically on the second side of the recess. The terminal end of the contact element is electrically connected to the terminal board.

[0028] In particular, the connector end is designed to be mechanically and firmly attached to the terminal board. Specifically, the connector end is soldered to the terminal board.

[0029] The technology disclosed herein further comprises a connection system. The connection system is designed for connecting separator plates of the fuel cell stack to a cell monitoring module. The connection system comprises at least one of the described connection elements, a cell monitoring board, and at least one of the connecting leads for electrically connecting the connection element, in particular the connection board, to the cell monitoring board.

[0030] The cell monitoring board is designed to accommodate the cell monitoring module. The cell monitoring module processes and evaluates the signals picked up via the connecting elements, or at least forwards the signals to a higher-level processing unit. The cell monitoring board, and therefore also the cell monitoring module, can be electrically connected to several of these connecting elements.

[0031] The advantageous embodiments and dependent claims described in the context of the disclosed connecting element are correspondingly advantageously applied to the disclosed connecting system.

[0032] The technology disclosed herein further comprises a fuel cell system. The fuel cell system is located, in particular, in a vehicle. The fuel cell system comprises at least one connection system as described above, a fuel cell stack with separator plates contacted by the connection element, and a cell monitoring module on the cell monitoring board. The advantageous embodiments and dependent claims described in connection with the disclosed connection element are correspondingly advantageously applied to the disclosed fuel cell system.

[0033] The technology disclosed herein further comprises a method for assembling the described connecting element. In this method, the contact element is inserted into the recess in the positive z-direction, i.e., from the first side of the recess towards the second side. The positive locking element then comes into contact with the housing. The detent element, preferably used, engages in the housing. The advantageous embodiments and dependent claims described in connection with the disclosed connecting element are correspondingly advantageously applied to the disclosed method.

[0034] The technology revealed here will now be explained using the schematic figures. They show: Fig. 1 a schematic representation of the fuel cell system, comprising the connection system with the connecting element, Fig. 2. Another schematic representation of the fuel cell system, including the connection system with connecting element, Fig. 3 a schematic sectional view of the connecting element, and Fig. 4 den in Fig. 3 marked section A:A.

[0035] The figures show the disclosed connecting element 5 as part of a connecting system 1 in a fuel cell system 2.

[0036] The fuel cell system 2 is used particularly in a vehicle. The fuel cell system 2 comprises a fuel cell stack with several separator plates 3. The separator plates 3 are in particular monopolar plates or bipolar plates of the fuel cell stack.

[0037] Furthermore, the fuel cell system 2 includes a cell monitoring module 4. The cell monitoring module 4 is electrically connected to the separator plates 3 via the connection system 1. The unit consisting of connection system 1 and cell monitoring module 4 can also be referred to as the cell monitoring system.

[0038] The connection system 1 comprises a connecting element 5, a cell monitoring board 6 for receiving the cell monitoring module 4 and a connecting line 7 for connecting the connecting element 5 to the cell monitoring board 6.

[0039] The Fig. 1 and Fig. Figure 2 shows the basic arrangement of several connecting elements 5 on the fuel cell stack. In particular, Fig. As can be seen from Figure 1, each connecting element 5 electrically contacts several of the separator plates 3 of the fuel cell stack. In the illustrated embodiment, this contact serves to connect the separator plates 3 to the cell monitoring module 4. However, the connecting element 5 disclosed here can also be used for other purposes of contacting the separator plates 3.

[0040] The connecting element 5 comprises a housing 510. The housing 510 contains, as shown in Fig. Figure 1 shows several contact elements 520 arranged for contacting several separator plates 3. The following describes how to... Fig. 3 and Fig. 4 The exact design and arrangement is described using the example of a contact element 520.

[0041] According to the Fig. 3 and Fig. 4. A connection board 530 is mounted on the housing 510. The connection board 530 sits on spacers 515 of the housing 510. The housing 510 can also be designed so that the connection board 530 is located inside the housing 510.

[0042] The housing 510 has a recess 511. The recess 511 is designed as a through-hole in the housing 510. The contact element 520 is inserted into this recess 511. The lower side of the housing 510 with respect to the recess 511 is referred to as the first side 512. The opposite side, above the recess 511 in the figures, is referred to as the second side 513. The terminal block 530 is located on the second side 513.

[0043] The contact element 520 has a contact end 521. An opening 522 is formed in the contact end 521. The contact end 521 of the contact element 520 fits into this opening 522 onto the separator plate 3 to be electrically contacted.

[0044] At the opposite end, the contact element 520 has a terminal end 523. The terminal end 523 is inserted into the terminal board 530 and is connected to the terminal board 530 both electrically and mechanically via a solder joint 531.

[0045] The contact end 521 is located on the first side 512 of the recess 511. The connection end 523 is located on the second side 513 of the recess 511.

[0046] On the first side 512 of the recess 511, a positive locking element 524 is formed on the contact element 520. The positive locking element 524 is an integral part of the contact element 520.

[0047] The figures show three axes, each perpendicular to the others. The individual separator plates 3 are located in a plane spanned by the y-axis and z-axis. Along the x-axis, the multiple separator plates 3 are stacked against each other.

[0048] A positive z-direction is defined from contact end 521 towards terminal end 523. The negative z-direction runs in the opposite direction. When the connecting element 5 is attached to the separator plates 3, it is attached along the negative z-direction. When the connecting element 5 is removed, it is pulled off along the positive z-direction.

[0049] During assembly of the connecting element 5, the contact element 520 is inserted into the housing 510 from below, i.e., in the positive z-direction. The recess 511 in the housing 510 is significantly smaller than the positive locking element 524. As a result, the positive locking element 524 rests against the housing 510 and blocks any further movement of the contact element 520 relative to the housing 510 along the positive z-direction.

[0050] Furthermore, a locking lug 514 is formed in the housing 510. The contact element 520 has a locking element 525. When the contact element 520 is mounted in the housing 510, the locking element 525 engages with the locking lug 514, creating a so-called primary locking connection. This locking connection can also be designed differently. For example, instead of the locking lug 514, a corresponding recess or undercut in the housing 510 can be used for the locking element 525 to engage.

[0051] To the side of the locking element 525, the housing 510 preferably has a through-hole 516 for inserting a pin removal tool to release the primary locking mechanism.

[0052] Fig. 4 shows the one in Fig. 3 marked section A:A. This schematic representation shows that, with appropriate design and positioning of the locking lug 514 and the positive locking element 524, the two elements can be arranged at approximately the same height or next to each other.

[0053] The preceding description of the present invention serves only for illustrative purposes and not to limit the invention. Various changes and modifications are possible within the scope of the invention without departing from the scope of the invention and its equivalents. Reference symbol list: 1 Connection system 2 Fuel cell system 3 separator plates 4 cell monitoring module 5 Connecting element 510 case 511 Recess 512 first page 513 second page 514 Rastnase 515 spacers 516 Passage opening 520 contact elements 521 contact ends 522 Opening 523 End of connection 524 Positive locking element 525 Latching element 530 connection board 531 Solder joint 6 cell monitoring board 7 further management

Claims

[1] Connecting element (5) for electrically contacting at least one separator plate (3) of a fuel cell stack, comprising • a housing (510), • a contact element (520) arranged in the housing (510) with a contact end (521) for contacting the separator plate (3) and with a connection end (523) for connecting to a further line (7), wherein a positive z-direction is defined from the contact end (521) in the direction of the connection end (523), • a recess (511) in the housing (510), wherein the contact element (520) is inserted in the recess (511), wherein the contact end (521) is arranged on a first side (512) of the recess (511), and wherein the terminal end (523) is arranged on the second side (513) of the recess (511), • wherein the contact element (520) has a positive locking element (524) which is positively locked to the first side (512) of the recess (511) on the housing (510), • wherein the contact element (520) has a detent element (525) which is engaged on the housing (510) and blocks movement of the contact element (520) in the negative z-direction. [2] Connecting element according to claim 1, wherein the recess (511) is smaller than the positive locking element (524), so that the contact element (520) can only be inserted into the recess (511) in a positive z-direction. [3] Connecting element according to one of the preceding claims, wherein the locking element (525) is arranged on the first side (512) of the recess (511). [4] Connecting element according to one of the preceding claims, wherein the contact element (520) comprises a base body made of sheet metal and the locking element (525) is a tongue bent out from the base body. [5] Connecting element according to one of the preceding claims, wherein the contact element (520) comprises a base body made of sheet metal and the positive locking element (524), preferably made of plastic, is attached to the sheet metal. [6] Connecting element according to one of the preceding claims, wherein the extending line (7) comprises a terminal board (530) in or on the housing (510) on the second side (513) of the recess (511), and the terminal end (523) is electrically connected to the terminal board (530). [7] Connecting element according to claim 6, wherein the connecting end (523) is mechanically fixed to the connecting board (530), preferably soldered. [8] Connecting element according to one of the preceding claims, wherein several of the contact elements (520) are arranged in the housing (510), each in its own recess (511). [9] Connection system (1) for connecting separator plates (3) of a fuel cell stack to a cell monitoring module (4), comprising • at least one of the connecting elements (5) according to one of the preceding claims, • a cell monitoring board (6) designed to accommodate the cell monitoring module (4), and • at least one of the connecting leads (7) from the connecting element (5) to the cell monitoring board (6). [10] Fuel cell system (2), preferably in a vehicle, comprising • at least one connection system (1) according to claim 9, • a fuel cell stack with separator plates (3), contacted by the connecting element (5), and • a cell monitoring module (4) on the cell monitoring board (6). [11] Method for assembling a connecting element (5) according to one of claims 1 to 8 for electrically contacting at least one separator plate (3) of a fuel cell stack, wherein the contact element (25) is inserted into the recess (511) in a positive z-direction.

Images