METHOD AND PRESS FOR INTRODUCING A DEFORMATION PATTERN INTO A SHEET

Abstract

A method and a press for introducing a deformation pattern into a sheet uses at least one tool unit for producing an electrolyser plate or fuel cell plate, wherein the deformation pattern in at least one sub-area has a plurality of identical pattern units lying beside one another with a pattern spacing in at least one pattern direction, and the press for forming only the sub-area comprises a tool unit, in which an upper and a lower forming die are arranged, with the interacting deformation structures of which at least one pattern unit of a sub-area is formed in a single stroke of the tool unit in the sheet guided between the forming dies, and with each stroke of a predetermined total number, the pattern introduced into the sheet is supplemented by at least one introduced pattern unit.

Claims

1. A method for introducing a deformation pattern into a sheet by using at least one tool unit of a press to produce an electrolyser plate or fuel cell plate, wherein a. the deformation pattern in at least one sub-area has a plurality of identical pattern units lying beside one another with a pattern spacing in at least one pattern direction, and b. for deforming only the at least one sub-area the press comprises a tool unit, in which an upper and a lower forming die are arranged, interacting deformation structures of the forming dies forming in the sheet at least one pattern unit of the at least one sub-area in a single stroke of the tool unit as the sheet is guided between the forming dies, and c. between two successive strokes of a predetermined total number of strokes of the tool unit, the sheet is transported onward within the tool unit in a conveying direction corresponding to the at least one pattern direction, and d. in the tool unit, with each stroke of the predetermined total number, the deformation pattern introduced into the sheet is supplemented by at least one of the pattern units until, after the predetermined total number of strokes, the sub-area of the deformation pattern has been completed, and e. with each stroke of the tool unit a positioning opening is die-cut in the sheet and a positioning pin is provided in the tool unit or the press, and before and/or with a closing movement of a stroke of the tool unit, the positioning pin moves into the positioning opening, and f. the positioning opening is arranged in a predetermined area of the sheet, subsequent, additional die-cutting step being carried out with another tool unit of the same press or another press in the predetermined area, wherein the positioning opening is removed by a die-cut made in the subsequent, additional die-cutting step, the die-cut thereby formed having a fluid-guiding function in a pack of a plurality of the electrolyser plates or fuel cell plates.

2. The method according to claim 1, wherein the interacting deformation structures of the lower and upper forming dies of the tool unit are used to introduce a number N of pattern units of the sub-area simultaneously in a single stroke of the tool unit, where N>=2.

3. The method according to claim 2, wherein after a stroke of the tool unit, as a result of the onward transport of the sheet, an area of the pattern unit formed in the sheet in an immediately preceding stroke is brought to overlap with the deformation structures of the upper and lower forming dies.

4. The method according to claim 2, wherein the sheet is moved onward in the conveying direction by M times the pattern spacing, where M<N.

5. The method according to claim 1, wherein the positioning opening is die-cut with a hole punch, and the hole punch and the positioning pin are arranged in the tool unit at a distance in the conveying direction which is smaller than M times pattern spacing.

6. The method according to claim 1, wherein the other tool unit of the same press or another press, also forms in the sheet pattern components of the deformation pattern and/or edge cuts which are arranged around the deformation pattern.

7. The method according to claim 6, wherein the other tool unit acts on the sheet in a single stroke in addition to the total number of strokes for forming the at least one sub-area.

8. (canceled)

9. An apparatus for carrying out the method according to claim 1, comprising the press having the at least one tool unit, wherein the tool unit has the upper and lower forming dies with the interacting deformation structures configured so that, in a single stroke of the tool unit, at least one of the pattern units of the sub-area of the deformation pattern is formed on the sheet, which deformation pattern has a plurality of the identical pattern units lying beside one another with the pattern spacing in the at least one pattern direction, and the tool unit is configured to shape the sub-area gradually with a plurality of strokes until the shaping of the sub-area has been completed, and the apparatus further comprises die-cutting means configured so that with each stroke of the tool unit the positioning opening is die-cut, and the positioning pin is provided in the tool unit or the press, the cutting-die and the positioning pin being so configured so that, before and/or with the closing movement of a stroke, the positioning pin is moved into the positioning opening, and the tool unit is configured to arrange the positioning opening in an area of the sheet in which a subsequent die-cutting step is carried out with the other tool unit of the same press or another press, the other tool unit being configured to form a die-cut which removes the positioning opening and which has a fluid-guiding function in a pack of a plurality of electrolyser plates or fuel cell plates.

10. The apparatus according to claim 9, wherein the tool unit has a conveying device configured to move the sheet onward within the tool unit between successive strokes by a multiple of the pattern spacing.

11. The apparatus according to claim 9, wherein the other tool unit is provided in another press or is substituted for the first tool unit in the same press and comprises a progressive die configured to form in a single stroke the pattern units of the deformation pattern and/or the die-cut positioning opening and/or edge cuts arranged around the sub-area.

Description

[0051] The following are brief descriptions of the drawings:

[0052] FIGS. 1A, 1B, 1C illustrate the interacting components of a tool unit during a first initial stroke;

[0053] FIGS. 2A, 2B, 2C show the same situation for a following second stroke of the tool unit after the sheet has been moved onward in the conveying direction;

[0054] FIGS. 3A-3C, 4A-4C, and 5A-5C show the repetition of the strokes and the associated positioning of the sheet with positioning geometry on a pin and also the introduction of a respective new positioning geometry by means of a hole punch with each stroke;

[0055] FIG. 6 shows the end result of the deformation with the tool unit after shaping of a sub-area of the deformation pattern has been built up gradually with a predetermined number of strokes;

[0056] FIGS. 7 and 8 show the product in perspective overview and in detail;

[0057] FIG. 9 shows a press according to the invention for carrying out the method, symbolically in an overview; and

[0058] FIG. 10 illustrates an embodiment in which the tool unit is used first in the press, the sheets fed to the press being firstly shaped only by the tool unit, i.e. the sub-area is shaped gradually.

[0059] FIGS. 7 and 8 discussed above show in a perspective overview and in detail the product produced from a flat sheet 1, in this case an electrolyser plate or bipolar plate or fuel cell plate, in particular from which an electrolyser or a fuel cell can be assembled by being stacked with other plates and elements.

[0060] The completely produced sheet 1 here has a deformation pattern, in particular also still further machining in addition thereto, for example die-cuts and edge-cut areas. In particular, this applies to all the sheets 1 produced in accordance with the invention, even outside the preferred application during the production of electrolyser plates or bipolar plates/fuel cell plates. The deformation pattern in all embodiments of the invention is provided by all the elevations and/or depressions relative to the plane of the originally not yet deformed sheet 1. It is produced as a result of deformation machining of the sheet 1, for example by deep-drawing and/or embossing.

[0061] Such elevations and/or depressions of the deformation pattern achieve different functions in the shaped sheet 1. In the preferred application they can, for example, form supporting structures via which adjacent sheets 1/electrolyser plates/bipolar plates are supported on one another or on other elements of a stack. They can, for example, also form sealing areas, in particular at the edge of the deformed and preferably cut sheet 1. A particularly significant, in particular enlarged-area, region in the deformation pattern is formed here by elevations and/or depressions which form the so-called flow field of the electrolyser plate or bipolar plate/fuel cell plate or of the sheet 1.

[0062] The flow field in this illustrated embodiment comprises a large number of elongated channels 6, which are all formed identically and which are located equidistantly beside one another at right angles to the longitudinal extension direction thereof. In other embodiments different to that shown, the flow field can also have another geometry. Even in the preferred application to electrolyser plates or fuel cell plates/bipolar plates, the invention is not restricted to the flow field actually illustrated. In particular, a flow field can also have other channel courses and/or channel portions but, according to the invention, has a periodicity of a pattern unit in the flow field.

[0063] This shows that the entire deformation pattern which is to be introduced into the sheet 1 by a press P, in particular by the at least one tool unit of the latter, has a sub-area which, in this preferred application, forms the flow field, which is distinguished by the fact that a pattern unit 6.1 is arranged therein repeatedly lying beside one another in at least one pattern direction 6.2 (here, e.g. exactly one single pattern direction), wherein the pattern units 6.1 lying beside one another all have the same pattern spacing 6.3. These relationships are illustrated by the detailed view of FIG. 8. The pattern in the sub-area therefore has a rapport or a periodicity which corresponds to the pattern spacing 6.3. The smallest pattern unit 6.1 of the sub-area in this case of the electrolyser plate or bipolar plate is a single channel 6. The pattern spacing 6.3 is the spacing between two adjacent channels 6 or between two pattern units 6.1.

[0064] Because of the large number of elevations and/or depressions which are to be produced in the largest-area part of the sheet 1, such a flow field cannot be produced or only with an economically unacceptable outlay by means of a single stroke with a tool unit of a press P, since this would have to be very strongly dimensioned for this purpose.

[0065] The invention is aimed at producing such a sub-area of an overall deformation pattern which can be broken down into identical pattern units 6.1 many times repeatedly in one and the same tool unit W1 and gradually with identically repeating strokes and always with the same pair of two forming dies 2/3 located opposite each other and moving in the stroke direction, between which the sheet 1 is moved onward in a conveying direction which corresponds to the pattern direction 6.2. The onward movement, e.g. by using a conveying device acting on the sheet, is carried out in a state in which the forming dies 2, 3 are at a distance from each other and form a gap between them. The pattern direction 6.2 is the direction in which the pattern units 6.1 are arranged lying beside one another. Here, the pattern direction 6.2 is at right angles to the longitudinal extension direction of the channels 6 and/or parallel to the longitudinal extension direction of the sheet 1.

[0066] FIGS. 1A, 1B, 1C illustrate the interacting components of a tool unit W1 during a first initial stroke, after which a sheet 1 to be shaped, preferably a sheet 1 that has not yet been deformed until then, was moved into this tool unit W1 in a conveying direction which corresponds to the pattern direction 6.2, in particular by a conveying device acting on the sheet 1.

[0067] FIG. 1A shows a horizontal section of a tool unit W1 of a press P with a view through of further elements in other planes parallel to the section plane of the sheet 1 lying therein, e.g. in an open state of the tool unit W1, in which the forming dies 2 and 3 are at a distance, so that the sheet 1 can be moved between the forming dies 2 and 3.

[0068] By way of example, a conveying device F, which preferably acts on the sheet 1 on both sides of the same in order to move it, is illustrated dashed in FIG. 1A. The exemplary illustration of the conveying device F chosen in FIG. 1A does not restrict the invention. Conveyance of the sheet 1 can also be achieved by other arrangements of a conveying device F.

[0069] For the open state, FIG. 1B shows the section A-A and the section B-B of FIG. 1A with magnified details. FIG. 1C shows the section A-A and the section B-B from FIG. 1A with magnified details for the closed state, in which therefore the forming dies 2 and 3 have been moved toward each other in order to transfer the deformation structure thereof into the sheet 1. The section A-A shows a section through the forming dies 2, 3, preferably centrally, and the section B-B shows a region which, at right angles to the conveying direction, is located laterally offset beside the forming dies 2/3.

[0070] The upper forming die 2 and the lower forming die 3 have deformation structures corresponding to one another (in particular negative relative to one another), with which a large number N of pattern units 6.1, here therefore, for example, channels 6, can be formed simultaneously in the sheet 1 with one stroke. The channels 6 are open in a direction at right angles to the sheet plane. This large number N of pattern units 6.1 which can be formed with the forming dies 2, 3 simultaneously in the sheet 1 in one stroke is smaller than the total number of all the pattern units 6.1 located in the sub-area of the deformation pattern, here the flow field. In this example, 14 pattern units 6.1 can be formed at the same time. This number is not restrictive for the invention and can in principle assume any desired value, in particular one which is smaller than the total number of the pattern units 6.1 in the sub-area and preferably is greater than 1.

[0071] The tool unit W1 has, besides the forming dies 2, 3 which can be moved toward and away from each other in the stroke direction, bolts 7, with which the sheet 1 can be fixed in its position in the tool unit W1 as it is deformed. Such bolts 7 can preferably be arranged around the forming dies 2, 3.

[0072] Laterally offset in a direction at right angles to the conveying direction 6.2 beside the forming dies 2, 3, in particular thus also beside the pattern to be introduced in the sub-area, a hole punch 5 and a pin as a positioning element 4 are provided as an element for introducing a positioning geometry. The hole punch 5 and positioning element 4 preferably form further tools of the total unit W1 in addition to the forming dies 2, 3.

[0073] In the first stroke of the tool unit W1, the pin 4 cannot yet move into a hole punched out by the hole punch 5 and perform a positioning as a result. On the other hand, during the initial movement into the tool unit W1, the sheet 1 can be moved in as far as the pin 4, e.g. until contact with the pin 4. Preferably, during the initial stroke, the positioning of the pattern units 6.1 to be introduced/to be formed is not critical, since there is no reference in the sheet 1 with which this first deformation must be aligned. Instead, the interaction of pin 4 with the positioning geometry 5.1 die-cut by the hole punch 5 leads to subsequent deformations of pattern units 6.1 being aligned with the previously formed pattern units 6.1, as will be described below.

[0074] In the lower detailed illustration of FIG. 1B, the arrangement of the not yet shaped sheet 1 between the forming dies 2, 3 is shown, wherein the upper detailed illustration shows that the sheet 1 has been moved as far as the pin 4. In this position of the sheet 1, a first stroke is carried out with the tool unit W1, i.e. the sheet 1 is clamped by the bolt 7 and the forming dies 2, 3 are moved toward each other, as a result of which their deformation structure is transferred into the sheet and therefore a number N (preferably N>1) of pattern units 6.1 is formed simultaneously; here, in this example, 14 pattern units 6.1 are formed.

[0075] The closed position of the tool unit W1 is shown by FIG. 1C. With the stroke for producing or forming the N pattern units 6.1, which is a subset of all the pattern units 6.1 of the sub-area, at the same time a positioning hole is also introduced into the sheet 1 as a positioning geometry 5.1, laterally offset beside the deformation in the sheet 1.

[0076] FIGS. 2A, 2B, 2C show the same situation for a following second stroke of the tool unit W1 after the sheet 1 has been moved onward in the conveying direction 6.2, which corresponds to the pattern direction, following the performance of the first stroke. In this way, an already shaped area is moved at least partly in the conveying direction beside the forming dies 2, 3.

[0077] In particular, the lower detailed illustration of FIG. 2B shows, with the tool unit W1 open, that as a result of the onward movement of the sheet 1, the previously created deformation is not moved completely beside the forming dies 2, 3, so that after a stroke of the tool unit W1, as a result of the onward transport of the sheet, an area of the shaped pattern produced in the previous stroke and trailing in the conveying direction is brought to overlap with the deformation structures of the upper and lower forming die.

[0078] Furthermore, the upper detailed illustration shows that the pin 4 overlaps the die-cut positioning geometry 5.1 following the onward transport of the sheet 1.

[0079] Starting from the second stroke and for each further stroke, it is thus true that as the tool unit W1 is closed during the stroke, as FIG. 2C shows, the tapered pin 4 moves into the positioning geometry 5.1; in this way the sheet 1 is positioned, in particular still before the complete closure of the forming dies 2, 3, preferably because the positioning geometry 5.1 is centred around the tapering free end of the pin 4.

[0080] In addition to the existing overlap between the deformation structure of the forming dies 2, 3 with a sub-area trailing in the conveying direction of the deformation of the N pattern units produced in the preceding stroke, very high relative positioning accuracy of the deformation added by the stroke relative to the previous deformation is achieved. It should be pointed out that the overlap shown in the figures is not absolutely necessary, since adequate positioning is also already achieved by the interaction of the pin 4 with the positioning geometry 5.1.

[0081] FIG. 2B makes it clear that, in this example, an overlap of the deformation structure of the forming dies 2, 3 takes place with some, here in particular 4, pattern units of the previous deformation. The sheet 1 is thus moved by M pattern units after a stroke, where M is smaller than the number N of pattern units which were introduced/formed or at least which can be introduced/formed in the previous stroke. In the example shown, the values are N=14 and M=10,so that the result is an exemplary overlap of N-M=4 pattern units.

[0082] With the following, second stroke, N (14) pattern units are thus again formed, of which M (10) pattern units are newly formed and N-M (4) pattern units, namely the pattern units 6.1 lying in the overlap, are shaped a second time. The distance between the pin 4 and the punch 5 for introducing the positioning geometry 5.1 is defined as a function of the movement width of the sheet 1 between two strokes. This distance is Mpattern spacing here.

[0083] As a result of the functionality described, a number N of pattern units 6.1 is formed in the sheet 1 with the first stroke, wherein, after an onward movement of the sheet by M pattern units, with M<N, that is to say with an existing overlap of N-M pattern units, with each following stroke the pattern formed in the sheet 1 is supplemented by M pattern units until, in the last stroke, the forming of the sub-area of the deformation pattern has been completed.

[0084] A predetermined total number of pattern units 6.1 to be formed in a sub-area of a deformation pattern can thus always be divided up to a whole number of strokes by the number of pattern units 6.1 that can be formed with a pair of forming dies 2, 3 and a selected overlap. The overlap thus serves only to supplement an increase in precision and can primarily be used to subdivide the total number of pattern units to a plurality of strokes in an expedient way.

[0085] The following FIGS. 3A-3C, 4A-4C and 5A-5C show the repetition of the strokes and the associated positioning of the sheet 1 with the positioning geometry 5.1 on the pin 4, and also the introduction of a respective new positioning geometry 5.1 by means of the hole punch 5 with each stroke.

[0086] FIG. 6 shows the end result of the deformation with the tool unit W1 after the shaping of the sub-area T of the deformation pattern has been built up gradually with a predetermined number of strokes. According to FIG. 6, the flow field made of the channels 6 is thus completed, the flow field being surrounded laterally by positioning geometries 5.1 created hereby.

[0087] By using at least one further tool unit W2, remaining parts of the deformation pattern, in particular deep-drawn areas or embossings, are now produced around the previously shaped sub-area T. In addition, by using the at least one further tool unit W2, preferably with exactly one single further tool unit W2, die-cuts 8 and/or edge cuts 9 and/or supporting geometries 10 and/or sealing channels 11 can also be created on the sheet 1 with a single stroke.

[0088] The arrangement of at least some of the die-cuts 8, which preferably serve as a passage for fluids in an electrolyser or a fuel cell, is such that the previously introduced positioning geometries 5.1 are removed again by these die-cuts 8.

[0089] FIG. 9 shows a press P according to the invention for carrying out the method, symbolically in an overview.

[0090] This comprises at least one first tool unit W1 in which, by means of a number of repeating strokes with the same pair of two forming dies, a sub-area of the deformation pattern which has pattern units 6.1 repeatedly lying beside one another is introduced or formed in the sheet 1. After the multiple strokes for completing the sub-area, the sheet 1 is transported from the first tool unit W1 into the second tool unit W2 of the press. The second tool unit W2 is here part of the same press P which also comprises the first tool unit W1.

[0091] In the tool unit W2, which takes over the iteratively shaped sheet 1 from the tool unit W1, the deformation pattern of the sheet 1 is completed, i.e. all the deformations which are provided in addition to the sub-area are made, preferably with a single further stroke. In addition, further die-cuts or cuts on the sheet can be performed in the same stroke. However, the invention can also provide for distributing the further machining of the sheet 1 after the tool unit W1 to a plurality of tool units W2, e.g. performing the remaining deformations with a further tool unit W2 and carrying out die-cuts and/or edge cuts with yet a further tool unit W2.

[0092] The tool units W1 and W2 can alternatively also be operated in different presses or chronologically one after another by means of exchanging them in the same press.

[0093] FIG. 10 illustrates an embodiment in which the tool unit W1 is used first in the press P. The sheets 1 fed to the press P are here firstly shaped only by the tool unit W1, i.e. the sub-area is shaped gradually, as provided by the invention. The sheets 1 shaped in this way are fed into a buffer 12.

[0094] Following the shaping of a predetermined number of sheets 1, in the press P the tool unit W1 is replaced by the tool unit W2, in particular with which those pattern components which are not a part of the produced sub-area T can be formed in the sheet 1. Following the replacement, the previously shaped sheets 1 are removed from the buffer 12 and fed to the press P again, in order then to shape these with the tool unit W2, in particular to complete them.