Method for making contact with a plurality of separator plates and fuel cell system

Abstract

A method for making contact with a plurality of separator plates of a fuel cell system includes the steps of: inserting at least one connecting element of a cell voltage monitoring system between two directly adjacent separator plates so that two connecting parts of the connecting element that are able to move with respect to one another are arranged at least in certain regions between the directly adjacent separator plates; and relatively moving the two connecting parts that are able to move with respect to one another so that at least one first connecting part of the connecting parts moves at least in sections toward a separator plate of the directly adjacent separator plates.

Claims

1. A method for making contact with a plurality of separator plates of a fuel cell system, the method comprising the steps of: inserting at least one connecting element of a cell voltage monitoring system between two directly adjacent separator plates so that two connecting parts of the connecting element that are able to slidingly move with respect to one another are arranged at least in certain regions between the directly adjacent separator plates, wherein the two connecting parts of the connecting element comprise a first part and a second part and wherein the first part is not monolithically formed with the second part; and relatively slidingly moving the two connecting parts that are able to slidingly move with respect to one another such that the first part of the two connecting parts slidingly moves along a sliding surface of the second part which extends at an angle to an insertion direction toward a separator plate of the directly adjacent separator plates wherein the two connecting parts are pushed apart at least in certain regions due to the slidingly moving along.

2. The method as claimed in claim 1, wherein the connecting parts that are able to slidingly move with respect to one another are displaced in parallel with the insertion direction of the connecting element.

3. The method as claimed in claim 1, wherein the connecting parts that are able to slidingly move with respect to one another are configured so as to be displaceable along a longitudinal axis of the connecting element.

4. The method as claimed in claim 1, wherein a plurality of connecting elements are each inserted between two directly adjacent separator plates, and the plurality of connecting elements each have two connecting parts that are able to slidingly move with respect to one another.

5. The method as claimed in claim 1, wherein the relatively slidingly moving is begun only after the insertion.

6. The method as claimed in claim 1, wherein contact pressure at least between one of the connecting parts and one of the directly adjacent separator plates is increased at least in sections due to the relatively slidingly moving.

7. A fuel cell system, comprising: a plurality of separator plates; and at least one connecting element for connection of the separator plates to a cell voltage monitoring system; wherein, in a first state, the connecting element is insertable between two directly adjacent separator plates; and wherein, in a second state, the connecting element exerts a higher contact pressure on at least one of the adjacent separator plates at least in certain regions than in the first state; and wherein the connecting element is transferrable from the first state to the second state by virtue of two connecting parts of the connecting element that are able to slidingly move with respect to one another slidingly moving relative to one another, wherein the two connecting parts of the connecting element comprise a first part and a second part, wherein the first part is not monolithically formed with the second part, and wherein the slidingly moving relative to one another comprises the first part slidingly moving along a sliding surface of the second part which extends at an angle to an insertion direction such that the two connecting parts are pushed apart at least in certain regions due to the slidingly moving along.

8. The fuel cell system as claimed in claim 7, wherein the connecting parts that are able to slidingly move with respect to one another are displaceable in parallel with the insertion direction of the connecting element.

9. The fuel cell system as claimed in claim 7, wherein the connecting parts that are able to slidingly move with respect to one another are configured so as to be displaceable along a longitudinal axis of the connecting element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic illustration of a fuel cell system 100.

(2) FIG. 2 is a schematic illustration of the separator plates 14, 14, 14 and the connecting elements 15, 15, 15 in the first state.

(3) FIG. 3 is a schematic illustration of the separator plates 14, 14, 14 and the connecting elements 15, 15, 15 in the second state.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 schematically shows a fuel cell stack of a fuel cell system 100 having a plurality of individual cells, of which in this case the individual cells 10.sub.1, 10.sub.2, 10.sub.3, 10.sub.4 are shown by way of example. The individual cells are held and prestressed by two end plates 30. Current collectors 20 are provided adjacent to the end plates 30. The separator plates are designed in this case as bipolar plates 14, 14, 14. In each case, one half of two directly adjacent bipolar plates 14, 14, 14 form an individual cell 10.sub.1, 10.sub.2, 10.sub.3, 10.sub.4 together with a membrane electrode assembly (MEA) 12, 12, 12 arranged between said plates. The bipolar plates 14, 14, 14 shown are connected to a cell voltage monitoring system 400, which is designed to monitor the state of the individual cells 10.sub.1, 10.sub.2, 10.sub.3, 10.sub.4. The connecting elements 15, 15, 15 are in this case illustrated only schematically and in a highly simplified manner. The connecting elements 15, 15, 15 ensure the electrical contact between the cell voltage monitoring system and the separator plates. In particular, the connecting elements 15, 15, 15 are each clamped between two directly adjacent separator plates. The connecting elements 15, 15, 15 are in this case connected directly to electronics components of the CVM system 400. For example, the connecting elements could be designed as contact pins or a printed circuit board or a flexible conductor printed circuit board, which make direct contact with a printed circuit board of the CVM system 400.

(5) FIG. 2 shows a connecting element 15, 15, 15 disclosed here in the first state. The connecting element 15, 15, 15 comprises two connecting parts 151, 152; 151, 152; 151, 152 that are able to move with respect to one another, which connecting parts are designed here so as to be displaceable along the longitudinal axis of the connecting element 15, 15, 15 and along the insertion direction E. For simplification, the displacement mechanism itself has been omitted here. The first connecting part 151, 151, 151 is located directly next to the second connecting part 152, 152, 152 of the connecting element 15, 15, 15. The second connecting part 152, 152, 152 comprises a free end that comes to a point in this case (not absolutely necessary), which end can be inserted into the intermediate space Z. The other end of the connecting element 15, 15, 15 can be connected directly or indirectly to the cell voltage monitoring system 400 (not illustrated). A widened region with the contact surface K.sub.2 follows counter to the insertion direction E behind the free end that comes to a point. A hollow region follows said widened region of the second connecting part 152, 152, 152 counter to the insertion direction E, gradually tapers and is received in the first connecting part 151, 151, 151 in the first state of the connecting element. Said gradually tapering transition region is the sliding surface G.sub.2 along which the first connecting part 151, 151, 151 can slide. The sliding surface G.sub.2 runs at an angle to the longitudinal axis of the connecting element 15, 15, 15 and to the insertion direction E.

(6) The first connecting part 151, 151, 151 also comprises a sliding surface G.sub.1, which in this case is expediently designed in a manner corresponding to the sliding surface G.sub.2 of the second connecting part 152, 152, 152. The first connecting part 151, 151, 151 and the second connecting part 152, 152, 152 are configured so that the first connecting part 151, 151, 151 can be received at least in certain regions, preferably completely, in the recess of the second connecting part 152, 152, 152. The connecting element 15, 15, 15 is designed, in particular, in such a way that, in the first state, the maximum thickness D of the section of the connecting element 15, 15, 15 that can be inserted into the intermediate space Z is less than or equal to the minimum spacing A of two adjacent separator plates. The connecting element 15, 15, 15 can therefore be inserted in a simple or in a simpler manner in the first state. The risk of faulty contact-connections can possibly be reduced as well.

(7) FIG. 3 shows the connecting element 15, 15, 15 and the separator plates 14, 14, 14 in the second state of the connecting element 15, 15, 15. The two connecting parts have been displaced relative to one another in parallel with (that is to say in or counter to) the insertion direction E. In this case, the sliding surfaces G.sub.1, G.sub.2 act as guides. The contact surfaces K.sub.1, K.sub.2 have been moved apart from one another due to the relative displacement of the two connecting parts and now press against the separator plates. Relatively large contact pressures are achieved here.

(8) For reasons of legibility, the expression at least one has sometimes been omitted for simplification. If a feature of the technology disclosed here is described in the singular or with the indefinite article (for example the/a fuel cell, the/a connecting element, the/a connecting part, the/a separator plate, the/a contact surface, the/a recess, the/a sliding surface, etc.), the plural thereof is also intended to be disclosed concomitantly at the same time (for example the at least one fuel cell, the at least one connecting element, the at least one connecting part, the at least one separator plate, the at least one contact surface, the at least one recess, the at least one sliding surface, etc.).

(9) The preceding description of the present invention serves only for illustrative purposes and not for the purpose of restricting the invention. Various alterations and modifications are possible in the context of the invention without departing from the scope of the invention and of its equivalents.

LIST OF REFERENCE SIGNS

(10) Fuel cell 10.sub.1, 10.sub.2, 10.sub.3, 10.sub.4 MEA 12, 12, 12 Separator plate 14, 14, 14 Connecting element 15, 15, 15 First connecting part 151, 151, 151 Second connecting part 152, 152, 152 Seal 17 Current collector 20 End plates 30 Fuel cell system 100 Cell voltage monitoring system 400 Connecting element thickness D Separator plate spacing A Edge R Contact surface K.sub.1, K.sub.2 Sliding surface G.sub.1, G.sub.2

(11) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.