Testing device for a fuel cell stack

Abstract

A testing device for a fuel cell stack has multiple fuel cells which are stacked along a stack axis with each having media openings in the form of through-holes. Corresponding media openings align to form media lines when in the stacked state. The testing device has a rod which can be introduced into a media line, and at least one sealing element which is arranged on the rod to seal off the media line and to isolate at least one fuel cell of the fuel cell stack from the other fuel cells, and/or at least one contact element which can be introduced with the rod to make electrical contact with an individual fuel cell inside the media line.

Claims

1. A testing device for a fuel cell stack, wherein the fuel cell stack comprises a plurality of fuel cells which are stacked along a stack axis and each have media openings in a form of through-apertures, and wherein, in a stacked state, corresponding media openings align to form media lines, wherein the testing device comprises: a rod which is introducible into a media line; and at least three spaced-apart sealing elements arranged on the rod for sealing the media line in order to isolate at least one fuel cell of the fuel cell stack from remaining fuel cells and to form at least two testing sections, each with at least one separated fuel cell; and/or at least one contact element which is introducible with the rod for making electrical contact with an individual fuel cell within the media line, wherein a fluid opening is formed on each of the at least two testing sections, and for each of the at least two testing sections, the rod comprises a fluid line which is connected to the fluid opening.

2. The testing device according to claim 1, wherein the at least three spaced-apart sealing elements are introducible with the rod into the media line.

3. The testing device according to claim 1, wherein the at least three spaced-apart sealing elements are inflatable to provide sealing.

4. The testing device according to claim 1, wherein the at least three spaced-apart sealing elements are retractable and extendable radially with respect to the rod.

5. The testing device according to claim 1, wherein each of the at least three spaced-apart sealing elements comprise at least one elastic annular sealing lip, a size and shape of which correspond to the media openings of the media line.

6. The testing device according to claim 1, further comprising: at least two spaced-apart contact elements for simultaneously making contact with two fuel cells in the media line.

7. The testing device according to claim 1, wherein the at least one contact element is arranged on one of the at least three spaced-apart sealing elements.

8. The testing device according to claim 1, wherein the at least one contact element is a sliding contact which slides on the fuel cells when the rod is introduced.

9. The testing device according to claim 1, further comprising: a detection unit arranged on the rod that detects a position of the rod relative to an individual fuel cell.

10. The testing device according to claim 9, wherein the detection unit is a sensor or camera.

11. A method for testing a fuel cell stack, wherein the fuel cell stack comprises a plurality of fuel cells which are stacked along a stack axis and each have media openings in a form of through-apertures, and wherein, in a stacked state, corresponding media openings align to form media lines, wherein the method comprises: introducing a testing device into one of the media lines; sealing the media line with the testing device in order to isolate at least one fuel cell of the fuel cell stack from remaining fuel cells, and acting upon the at least one isolated fuel cell with a fluid for measuring tightness, measuring flow rate or measuring pressure drop, and/or making electrical contact with an individual fuel cell within the media line with the testing device, making electrical contact with the fuel cell stack at a further point, and carrying out a short circuit measurement between the two contacts.

12. The method according to claim 11, wherein two testing devices are introduced respectively into two media lines, the two media lines are connected via media channels which run in the fuel cells perpendicularly to the stack axis, and with the two testing devices, the same at least one fuel cell of the fuel cell stack is separated from the remaining fuel cells.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a fuel cell stack to be tested.

(2) FIG. 2 shows an individual fuel cell.

(3) FIG. 3 shows the testing device presented here in the fuel cell stack.

(4) FIG. 4 shows the testing device in detail.

(5) FIG. 5 shows a variant of the testing device in the fuel cell stack.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) The figures purely schematically show a testing device 1 for testing a fuel cell stack 20. The testing method presented here is carried out by use of the testing device 1 shown.

(7) FIG. 1 purely schematically shows the fuel cell stack 20 with fuel cells 21, current collector plates 24, insulation plates 23 and end plates 22. The individual stack elements of the fuel cell stack 20 are stacked along a stack axis 29.

(8) One of the end plates 22, in the form of a media plate, is located on an end side of the fuel cell stack 20. Via said end plate 22, the media is supplied to the fuel cell stack 20 and the media is discharged from the fuel cell stack 20.

(9) The current collector plates 24 are located between the fuel cells 21 and the end plates 22. The current collector plates 24 are electrically insulated from the end plates 22 via insulation plates 23.

(10) A plurality of media openings 26 (see FIG. 2) are in each case formed in the end plate 22, which is designed as a media plate, in the fuel cells 21 and in the insulation plate 23 and current collector plate 24 that lie inbetween. Corresponding media openings 26 are aligned in the fuel cell stack 20 and thereby form media lines 25 which are oriented parallel to the stack axis 29.

(11) FIG. 2 shows an individual fuel cell 21 in a plane perpendicular to the stack axis 29. The part of the fuel cell 21 that is relevant here, namely the separator plate or bipolar plate, can be seen. On the side shown, two of the media openings 26 which form two associated media lines 25 in the fuel cell stack 20 are surrounded by a sealing line 27. The two media openings 26 are connected via a media channel 28 which meanders perpendicularly to the stack axis 29.

(12) Conventionally, the media lines 25 for the inflow and outflow of the oxidant on the one side of the separator plate and the media lines 25 for the inflow and outflow of the fuel on the other side are connected via corresponding media channels 28. In the interior of the separator plate, the cooling liquid conventionally flows via media channels 28 between the two corresponding media lines 25.

(13) FIG. 3 purely schematically shows a section through the fuel cell stack 20. Two associated media lines 25, for example the two media lines 25 for the oxidant, can be seen here.

(14) Furthermore, FIG. 3 shows two of the testing devices 1. The individual testing device 1 has a rod 2. The rod 2 stands parallel to the stack axis 29 and can be introduced into the media line 25.

(15) Two sealing elements 3 are located on the rod 2. The two sealing elements 3 are spaced apart from each other. What is referred to as a testing section is defined between the two sealing elements 3.

(16) A fluid opening 5 is formed in the rod 2. When the test is being carried out, a corresponding fluid can be introduced into the testing section between the two sealing elements 3, or discharged from there, via said fluid opening 5.

(17) Furthermore, at least one of the two testing devices 1 has contact elements 4. In the example shown, said contact elements 4 for making electrical contact with the fuel cells 21 are located on the outer circumference of the sealing elements 3.

(18) The two testing devices 1 are positioned at a fixed distance from each other via a testing receptacle 9.

(19) FIG. 4 shows an individual testing device 1 in detail. It is purely schematically illustrated here that a fluid line 6 leads outward from the fluid opening 5. In particular, said fluid line 6 runs in the interior of the rod 2. The fluid exchange with the testing section between the two sealing elements 3 is possible via the fluid line 6.

(20) Furthermore, the schematic illustration in FIG. 4 shows that the contact elements 4 are located on the electrically conductive circumference of the sealing element 3. Said electrically conductive circumference of the sealing element 3 is connected in an electrically conductive manner to an electrical line 7. The electrical line 7 leads outward, in particular through the rod 2.

(21) FIG. 4 shows an actuating device 8 likewise purely schematically. The actuating device 8 is actuable from the outside via a corresponding line or mechanical connection. Said line or mechanical connection also runs through the rod 2.

(22) The individual sealing element 3 is configured, for example, so as to be inflatable. Accordingly, in particular a pressure line leads to the actuating device 8. The inflating pressure can be guided to the sealing elements 3 via the actuating device 8. As an alternative thereto, it is also possible, for example, to mechanically retract and extend the individual sealing element 3 radially with respect to the rod 2 via the actuating device 8.

(23) At least one testing apparatus 10 is located outside the media line 25. The electrical line 7 and/or the fluid line 6 and/or the lines or mechanical connections of the actuating device 8 preferably lead to said at least one testing apparatus 10.

(24) The testing apparatus 10 is preferably designed to apply a corresponding voltage to the contact elements 4 and/or to evaluate a measured electrical signal.

(25) The testing apparatus 10 is preferably designed to actuate the actuating device 8 in order to bring the sealing elements 3 into their sealing position.

(26) The testing apparatus 10 is preferably designed to conduct a fluid into the testing section between the two sealing elements 3 and/or to measure pressure changes or flow quantities of the fluid.

(27) FIG. 4 purely schematically shows a detection unit 11 of the testing device 1. The detection unit 11 is introduced together with the rod 2 into the media line 25. The detection unit 11 is located in particular on the rod 2 or on one of the sealing elements 3. The detection unit 11 is, for example, a camera. The position at which the testing device 1, in particular the sealing elements 3, is/are located can be checked by use of said camera.

(28) FIGS. 3 and 4 show a positioning of the sealing elements 3 on the rod 2 with a testing section in which just one fuel cell 21 or a media channel 28 is located. However, it is also possible to space the two sealing elements 3 further from each other such that a plurality of fuel cells 21 are separated and checked with one operation.

(29) FIG. 5 shows a simplified variant of the testing device 1. In this testing device 1, just one sealing element 3 which is introduced into the media line 25 is located on the rod 2. The media line 25 is closed on the outer side by the other sealing element 3. Said outer sealing element 3 can likewise be located on the rod 2, but is not introduced into the media line 25. It is also possible by means of this simplified design to separate and to check individual fuel cells 21.

(30) In particular, it is provided that the rod 2 can be guided in a slidable manner through the outer sealing element 3. The testing section can thereby be increased or reduced in size by individual fuel cells 21 step by step. The outer sealing element 3 remains in situ here. The inner sealing element 3 is moved with the rod 2.

(31) Furthermore, FIG. 5 shows that the testing device 1 has only one contact element 4. A further contact element 4 is located at any desired point of the fuel cell stack 20. A short-circuit measurement at only selected fuel cells 21 is thus also possible.

LIST OF REFERENCE SIGNS

(32) 1 Testing device 2 Rod 3 Sealing element 4 Contact element 5 Fluid opening 6 Fluid line 7 Electrical lines 8 Actuating device 9 Testing receptacle 10 Testing apparatus 11 Detection unit 20 Fuel cell stack 21 Fuel cells 22 End plate 23 Insulation plate 24 Current collector plate 25 Media line 26 Media opening 27 Sealing line 28 Media channel 29 Stack axis

(33) 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.