DE102015224125A1 - Manufacturing method of a separator plate and a fuel cell system - Google Patents

Abstract

The technology disclosed herein relates to a method of manufacturing a multi-fuel cell fuel cell system. It comprises the steps of: 1) producing a plurality of separator plates, and 2) assembling the separator plates and other components into a fuel cell stack. The method of manufacturing the separator plate includes the step of attaching at least one contact element to the separator plate prior to assembling the fuel cell.

Description

The technology disclosed herein relates to a manufacturing method of a separator plate and a manufacturing method of a fuel cell system. The technology disclosed here relates in particular to the electrical connection of separator plates of a fuel cell system to a system for monitoring a plurality of fuel cells. As a rule, such a cell monitoring system (CVM system) monitors a large number of fuel cells. The individual fuel cells are usually connected by individual cables with the CVM system. Also is a plug from the DE102007003506 B4 known, the individual separator plates of the fuel cell contacted.

There is a need to connect the many fuel cells as cost-effective, fail-safe, fail-safe and / or space-saving as possible to a CVM system.

It is an object of the technology disclosed herein to reduce or eliminate the disadvantages of the prior art solutions. Other objects arise from the beneficial effects of the technology disclosed herein. The object (s) is / are solved by the subject matter of the independent claims. The dependent claims are preferred embodiments.

The technology disclosed herein relates to a manufacturing method for a fuel cell system and a fuel cell system. The fuel cell system includes a plurality of fuel cells. The fuel cell system is intended, for example, for mobile applications such as motor vehicles, in particular for providing the energy for at least one drive machine for locomotion of the motor 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. The fuel cell includes an anode and a cathode separated by an ion-selective or ion-permeable separator. The anode has a supply for a fuel to the anode. Preferred fuels are: hydrogen, low molecular weight alcohol, biofuels, or liquefied natural gas. The cathode has, for example, a supply of oxidizing agent. Preferred oxidizing agents are, for example, air, oxygen and peroxides. The ion-selective separator can be designed, for example, as a proton exchange membrane (PEM). Preferably, a cation-selective polymer electrolyte membrane is used. Materials for such a membrane are, for example: Nafion ^®, Flemion ^® and Aciplex ^®. A fuel cell system comprises at least one fuel cell and peripheral system components (BOP components) that can be used during operation of the at least one fuel cell. As a rule, several fuel cells are combined to form a fuel cell stack or stack. The fuel cell system further includes the separator plate disclosed herein.

The fuel cells of the fuel cell system include i.d.R. two separator plates. The ion-selective separator of a fuel cell is i.d.R. each arranged between two separator plates. The one separator plate forms the anode together with the ion-selective separator. The further separator plate arranged on the opposite side of the ion-selective separator, however, forms the cathode together with the ion-selective separator. Gas channels for fuel or for oxidants are preferably provided in the separator plates.

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 second side forming a cathode together with another ion-selective separator of an adjacent fuel cell.

Between the ion-selective separators and the separator plates are i.d.R. still so-called gas diffusion layers or gas diffusion layers (GDL) provided.

The technology disclosed herein includes a method of manufacturing a separator plate for a fuel cell. Further, the technology disclosed herein includes a method of manufacturing the multi-fuel cell fuel cell system disclosed herein. The method of manufacturing a fuel cell system includes the step of making a plurality of separator plates by the method of manufacturing a separator plate disclosed herein.

The method suitably comprises the step of attaching at least one contact element on the separator plate before assembling the fuel cell or the fuel cell stack.

The contact element is thus expediently a separate component, which is mounted by a further step to the separator plate. The contact element can be fastened in particular by a material connection to the separator plate. Cohesive connections are all compounds in which the connection partners through atomic or molecular forces are held together. As a rule, they are non-detachable compounds which can only be separated by destroying the connection means. The cohesive bonding methods include, for example, soldering, welding and / or gluing. Not included in the term "cohesive connection" are embodiments in which the pins are produced simultaneously with the separator plate from the separator plate semi-finished product itself by forming (eg a bead).

The technology disclosed herein also relates to a separator plate for a fuel cell having at least one contact element, wherein the contact element is firmly bonded to the separator plate. The features shown with respect to the method disclosed herein may also be embodied in the separator plate disclosed herein and / or the fuel cell system disclosed herein.

The at least one contact element may be formed as a contact pin or as an electrical line. It is therefore preferably an element that conducts the electric current well or conducts better than the other material of the separator plate. Preferably, the separator plate and the contact element are made of different materials. The contact element may be made of copper or its alloys, for example. In particular, the contact element may be provided on the separator plate such that the contact element at least partially increases the rigidity of the separator plate. Preferably, the separator plate is made of a metal sheet, wherein a contact element is applied to the surface of the separator plate.

An electrical line can also be referred to as an electrical cable, in particular as a one or multi-core composite of cores (individual lines) sheathed with insulating materials, which serves for the transmission of energy and / or information. Likewise, an electrical line embedded in a flex conductor or flex cable can also be included.

The at least one contact element may have a free end. The free end of the contact element is the end of the contact element, which is not attached to the Separatorplatte. In particular, a phase and / or a rounding can be provided at the free end. Such a phase and / or rounding can make it easier to put on a plug. Furthermore, the risk that the contact pin deforms during the assembly of a plug can be reduced. It can therefore be advantageously installed fail-safe and faster.

According to the technology disclosed herein, the at least one contact element is attached prior to assembly of the fuel cell, in particular prior to assembly of the fuel cell stack. In other words, first the contact elements are attached to the separator plates and then the components of the fuel cell stack are stacked. Initially, the fuel cells can be created individually and then the individual cells can be layered. Preferably, the individual fuel cells arise only when merging the components of the fuel cell stack. The assembly of the separator plates and the other components to a fuel cell stack thus takes place after the attachment of the contact element on the separator. However, bipolar plates are expediently used.

The at least one contact element may in particular be arranged and configured such that the contact element can be connected directly or indirectly to a cell monitoring system. The cell monitoring system (CVM) may be configured to monitor the condition of at least one cell. I.d.R. It monitors the condition of a variety of fuel cells. Monitoring in this context means that the system can directly or indirectly determine the state of the monitored cells. Advantageously, an occurring degradation or a cell failure can be detected early and appropriate countermeasures initiated. It may possibly increase the life span to a certain extent and / or increase the performance of the cell population by means of suitable countermeasures.

Advantageously, at least one measured variable can be detected directly or indirectly. The measured variable may in particular be the electrical voltage of the monitored cell. Advantageously, the single cell voltages of several or all cells and the total voltage are determined. Preferably, the current flowing through the fuel cell stack is further determined. From the measured voltages, the CVM system can determine, for example, one of the following values: minimum, maximum and mean value of the single-cell voltage. Advantageously, voltage deviations between the individual cells or at an average of the individual cell voltages can thus be detected. Preferably, further single-cell analysis methods are performed, such as an impedance calculation (e.g., electrochemical impedance spectroscopy).

In particular, the individual, several or all contact elements after assembling the components to a Fuel cell stack can be connected to the cell monitoring system. The contact elements facilitate contacting the separator plates. The contact elements may be formed as electrical lines. The free ends of the electrical leads can be held after assembly. A positioning device, for example a kind of comb, can be designed to grip or accurately position the individual lines (in particular their free ends). The held free ends can then be connected directly or indirectly to a cell monitoring system. Thus, advantageously, a simple, fail-safe and cost-effective installation of a CVM system can be realized. The contact elements can be connected, for example via a plug element with the cell monitoring system, wherein the plug element is designed to contact contact elements of different separator plate.

Preferably, the at least one separator plate has at least one recess. The at least one cutout can be arranged and configured such that the at least one cutout spans an area in which at least one contact element of at least one adjacent separator plate is arranged. At least one contact element of at least one adjacent separator plate may in particular be designed and arranged such that the at least one contact element projects at least partially into the recess. The recess is also to be considered in this connection if the separator plate as a whole is shortened in comparison with the directly adjacent separator plate (i.e. recessed over the entire side). Thus, advantageously, the space for contacting the contact pins by a plug element can be increased and / or the required installation space for the fuel cell stack can be reduced.

In other words, the technology disclosed herein relates to a method in which a contact element, ideally in the production process of the separator, is fixed on the separator plate. The contact element can serve as a counter pole to a CVM plug (instead of the separator plate itself). The contact element may be welded, electrically conductively bonded and / or soldered, for example. The contact element can be applied during embossing and / or the welding process of the bipolar plate or after the coating. The contact element can be added by a manufacturing robot directly during manufacture. An offset of the cable position or the cable direction may be provided. This can facilitate the assignment when stacking. When pushing on previously known plug on the Separatorplatten it came to uneven contact resistance of the individual plug-in elements. These uneven contact resistances could adversely affect the measurement results. The technology disclosed here allows more defined and fail-safe contacts and thus better measurement results. Furthermore, with the method disclosed herein, the number of male and male housings (see FIG. DE102007003506 B4 ) are significantly reduced. This is accompanied by a significant reduction in the required installation space and weight. Moreover, a better isolation of the individual components can be realized.

The technology disclosed herein will now be explained with reference to the figures. Show it:

1 a schematic side view of the fuel cell stack 100 ;

2 a schematic plan view of a bipolar plate 14 ;

3 a schematic plan view of a bipolar plate 14 ';

4 a schematic plan view of a bipolar plate 14 ;

5 a schematic plan view of a bipolar plate 14 ';

6 a schematic detail view of a bipolar plate 14 with a contact pin 15 ;

7 a schematic detail view of a bipolar plate 14 with a trained as an electrical line contact element 15 ; and

8th to 10 various embodiments in a schematic side view of a fuel cell stack 100 ,

The 1 schematically shows a fuel cell stack 100 with a large number of single cells, of which the single cells are an example 101 . 102 . 103 . 104 are shown. The single cells are separated by two endplates 30 held and biased. Adjacent to the end plates are current collectors 20 intended. The separator plates are here as bipolar plates 14 . 14 ' . 14 " educated. One half each of two adjacent bipolar plates 14 . 14 ' . 14 " form together with a membrane arranged between them Electrode Assembly (MEA) 12 . 12 ' . 12 " a single cell 101 . 102 . 103 . 104 out. The bipolar plates shown are connected to a cell monitoring system 400 connected, which is designed to monitor the state of the individual cells. The contact elements 15 . 15 ' . 15 " are here on the bipolar plates 14 . 14 ' . 14 " attached and project laterally to the plug element shown here in dashed lines 40 out. The plug element 40 connects the plug element 40 with a control unit 400 . for example via a data bus. Instead of a plug element 40 can also have multiple connector elements 40 be provided. In the plug element 40 For example, clamping elements 42 be arranged. The clamping elements 42 may in particular be arranged and configured such that the contact pins 15 . 15 ' . 15 " can be inserted into these clamping elements, and that the clamping elements 42 the contact pins 15 . 15 ' . 15 " pinch, creating an electrical contact. In particular, the clamping elements 42 be elastically resilient (see. 6 ).

The 2 shows a plan view of an anode side of the bipolar plate 14 , The fuel supply channel 130 , the fuel discharge channel 150 , the oxidation supply channel 160 , the oxidation discharge channel 180 , the coolant supply channel 170 and the coolant discharge channel 190 here are perpendicular to the drawing plane. These channels could be in the bipolar plate 14 be arranged differently. The seal 17 surrounds the media channels and the flow field and seals the fuel cell to the environment. The contact element 15 protrudes here from the immediately adjacent edge regions R ₁₅ and the rest of the edge R of the bipolar plate 14 out. A large part of the contact element 15 is however on the bipolar plate 14 arranged and welded to this. Furthermore, here is the contact element 15 still from the poetry 17 surrounded on both sides. But that does not have to be this way. However, an advantage of such a configuration is that the sealing compound is the contact element 15 and the bipolar plate 14 additionally stiffened in the contact area. Furthermore, the sealing compound can also via the contact element 15 run and isolate this better. Unless explicitly stated otherwise, the other features included in the 3 to 6 are shown, with the features of the embodiment according to the 2 to match.

The 3 shows a plan view of another bipolar plate 14 ' immediately adjacent to the bipolar plate 14 is arranged (see. 1 ). The contact element 15 the immediately adjacent bipolar plate 14 is shown in dashed lines. It is good to see that the contact element 15 the immediately adjacent bipolar plate 14 laterally offset to the contact element 15 ' the bipolar plate shown here 14 ' is arranged. The offset is in particular such that a plug element 40 (see. 1 ) can be mounted or mounted more easily. Offset here means an offset in a direction perpendicular to the fuel cell stack longitudinal axis or stacking direction Z.

The 4 shows a plan view of a bipolar plate 14 as they are in the 2 is shown. In contrast to 2 However, here is immediately adjacent to the contact element 15 the bipolar plate 14 a recess 18 the bipolar plate 14 shown. In this recess 18 is the contact element 15 " the immediately adjacent bipolar plate 14 " arranged (cf. 1 ). Here is the contact element 15 " made so large or stable that it is in the recess 18 protruding in the Z direction. By this interlocking arrangement, a more compact fuel cell stack can be achieved, which also has stable contact elements.

The 5 shows a plan view of another bipolar plate 14 ' immediately adjacent to the bipolar plate 14 of the 4 is arranged (see. 1 ). The bipolar plate 14 ' has another recess 18 ' on, which is cut out here as the recess 18 the immediately adjacent bipolar plate 14 , In this recess 18 ' can the contact elements 15 " and 15 intervention. Thus, a stepped plug element could be in the recesses 18 . 18 ' engage and the contact elements 15 . 15 ' 15 " to contact. Likewise, but could the recess 18 ' only the contact element 15 , In particular, only the dot-dash area to save, the immediately adjacent bipolar plate 14 symbolizes.

The 6 shows an enlarged view of the clamping element 42 in that here a contact element designed as a contact pin 15 electrically conductive contacted. At the free end 152 of the contact element 15 Here is a rounding provided, the pushing on of the clamping element 42 facilitated. Previously known solutions which directly contact the bipolar plates were pushed onto comparatively sharp-edged sheet-metal sections. This resulted in damage to the bipolar plate and / or irregular contact resistance.

The 7 shows an enlarged view of a formed as an electrical line contact element 15 , The electrical line comprises a fixed end 156 directly to the bipolar plate 14 is attached. Furthermore, the electrical line also includes a free end 154 which is not attached to the bipolar plate. The free end 154 is over an insulated line section from the fixed end 156 and from the bipolar plate 14 spaced. Through this before stacking to the bipolar plate 14 attached cable increases the flexibility in the design of the electrical connection to the CVM system 400 , The individual electrical lines 15 The individual bipolar plates can be transferred after stacking via an automated positioning in a defined position, for example by a separating element (here a comb K) of the positioning immediately adjacent to the edge R of the bipolar plates to the electrical lines (in this area is the position of the individual defined electrical lines) is applied and then the separating element K is moved away from the edge R to the free end 154 of the Lines in or immediately adjacent to the separating element K is arranged. In this second position are the individual positions of the free ends 152 well defined. The positioning device can then free these ends 152 continue to fix to establish an electrical connection to the CVM system, for example by a plug element 40 on the free ends 152 is put on.

The 8th schematically shows a detailed view of an embodiment according to the 2 and 3 , Simplifying were at the 8th to 10 the seals omitted. The contact elements 15 . 15 ' . 15 " are dimensioned here so that they are in the space between two directly adjacent bipolar plates 14 . 14 ' . 14 " can be arranged without an electrical short circuit between two directly adjacent bipolar plates formed by these contact elements. Here are no recesses 18 . 18 ' . 18 " intended.

The 9 schematically shows a detailed view of an embodiment according to the 4 and 5 , The recesses 18 . 18 ' . 18 " allow the use of larger contact elements with approximately the same package. It would also be possible here, a stepped plug element 40 to provide that the contact elements 15 . 15 ' . 15 " contacted at the same time. Not shown is another bipolar plate 14 " with the recess 18 " into which the contact element 15 ' intervenes. This recess 18 " is not located at the edge of the bipolar plate, but spaced from the edge between the flow field and the edge.

10 shows a further embodiment in which the contact elements 15 . 15 " two immediately adjacent bipolar plates 14 . 14 " pointing towards each other and in recesses 18 . 18 " the immediately adjacent bipolar plates 14 . 14 " intervention. This embodiment also allows a compact construction.

The figures above exemplify the technology disclosed herein. However, the technology disclosed herein is not limited to the specific embodiments shown in the figures. For example, it is also possible to use monopolar plates instead of bipolar plates. The disclosure regarding a bipolar plate is thus also applicable to a monopolar plate. These two types of plates can generally be referred to as Separatorplatten. If a separator plate is mentioned here, this should always include a monopolar plate and also a bipolar plate. Further, here the contact elements from the immediately adjacent edge R ₁₅ and also in relation to the entire edge R of a Separatorplattenseite are shown formed above. But that does not have to be this way. For example, the contact element may also not be formed protruding with respect to the immediately adjacent edge R ₁₅ and / or with respect to the entire edge R of a separator plate side. In one embodiment, for example, the contact element may be formed protruding only relative to the immediately adjacent edge regions R ₁₅ and not protruding with respect to other edge regions of the edge of a separator plate side. In other words, a protruding contact element can then be arranged even in a set-back region of a separator plate. The contact element 15 . 15 ' . 15 " as well as the recess 18 . 18 ' . 18 " Likewise, they can not be arranged in a corner area but in a middle area of a separator plate side. Furthermore, an insulator, which is preferably part of a subframe (= means for holding the MEA), can be arranged between a contact element and an immediately adjacent separator plate.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting 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.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting 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.

LIST OF REFERENCE NUMBERS

101, 102, 103, 104

fuel cell

 12, 12 ', 12 "

MEA

 14, 14 ',

 separator

 15, 15 ', 15 "

 contact element

 17

 poetry

 18, 18 ', 18 "

 recess

20

 pantograph

30

 endplates

 40

 male member

 42

 clamping element

 100

 fuel cell stack

 130

 Fuel supply channel

150

 Fuel discharge channel

 160

 Oxidation supply channel

 170

 Coolant supply channel

 180

 Oxidation discharge channel

 190

 Coolant discharge channel

 152, 154

 free end

 156

 solid end

400

 Cell monitoring system

 R

 edge

 K

 Comb

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007003506 B4 [0001, 0020]

Claims (11)

Method for producing a separator plate ( 14 . 14 ' . 14 " ) for a fuel cell ( 101 . 102 . 103 . 104 ), comprising the step of attaching at least one contact element ( 15 . 15 ' . 15 " ) on the separator plate ( 14 . 14 ' . 14 " ) before assembling the fuel cell. Method according to claim 1, wherein the at least one contact element ( 15 . 15 ' . 15 " ) is arranged and configured such that the contact element ( 15 . 15 ' . 15 " ) directly or indirectly with a cell monitoring system ( 400 ) is connectable. Method according to claim 1 or 2, wherein the at least one contact element ( 15 . 15 ' . 15 " ) is a contact pin or an electrical line. Method according to one of the preceding claims, wherein the at least one contact element ( 15 . 15 ' . 15 " ) by a material connection to the separator plate ( 14 . 14 ' . 14 " ) is attached. Method according to one of the preceding claims, wherein the at least one contact element ( 15 . 15 ' . 15 " ) a free end ( 152 . 154 ), wherein at the free end ( 152 . 154 ) a phase and / or rounding is provided. A method for producing a fuel cell system with a plurality of fuel cells, comprising the steps: - producing a plurality of separator plates ( 14 . 14 ' . 14 " ) by means of a method according to one of the preceding claims, and - assembling the separator plates ( 14 . 14 ' . 14 " ) and other components to a fuel cell stack. Method according to claim 6, wherein the contact elements ( 15 . 15 ' . 15 " ) are formed as electrical lines, wherein free ends ( 154 ) of the electrical leads are held after assembly, and wherein the free ends ( 154 ) directly or indirectly with a cell monitoring system ( 400 ) get connected. Method according to claim 6 or 7, wherein the contact elements ( 15 . 15 ' . 15 " ) via a plug element ( 40 ) with the cell monitoring system ( 400 ), wherein the plug element is formed, contact elements ( 15 . 15 ' . 15 " ) of different separator plate ( 14 . 14 ' . 14 " ) to contact. Method according to one of claims 6 to 8, wherein at least one separator plate ( 14 . 14 ' . 14 " ) at least one recess ( 18 . 18 ' . 18 " ), wherein the at least one recess ( 18 . 18 ' . 18 " ) is arranged and formed such that the at least one recess ( 18 . 18 ' . 18 " ) an area of the separator plate ( 14 . 14 ' . 14 " ), in which at least one contact element ( 15 . 15 ' . 15 " ) at least one adjacent separator plate ( 14 . 14 ' . 14 " ) is arranged. Method according to claim 9, wherein the at least one contact element ( 15 . 15 ' . 15 " ) of the at least one adjacent separator plate ( 14 "' ) is designed and arranged such that the at least one contact element ( 15 . 15 ' . 15 " ) at least partially into the at least one recess ( 18 . 18 ' . 18 " ) protrudes. Separator plate ( 14 . 14 ' . 14 " ) for a fuel cell ( 101 . 102 . 103 . 104 ) comprising at least one contact element ( 15 . 15 ' . 15 " ), wherein the contact element cohesively on the Separatorplatte ( 14 . 14 ' . 14 " ) is attached.

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