METHOD FOR MANUFACTURING A STAMPED MEMBER

Abstract

A method for manufacturing a stamped member includes the steps of: (1) stamping sheet metal within a stamping press system; (2) assembling the stamped sheet metal with other stamped members to form a plurality of bipolar plates; (3) pre-compressing the first bipolar plate between a pair of flat fixture plates; (4) obtaining first contact pressure variation data; (5) providing a customized patterned fixture which corresponds to the first contact pressure measurement data; (6) pre-compressing the second bipolar plate with the customized patterned fixture; and (7) obtaining second contact pressure variation data.

Claims

1. A method for manufacturing a bipolar plate comprising the steps of: stamping sheet metal within a stamping press system to form a plurality of stamped members; assembling the plurality of stamped members to form a plurality of bipolar plates; and pre-compressing the bipolar plate between a pair of flat fixture plates; obtaining first contact pressure variation data of at least two metal bead regions stamped in the bipolar plate; providing a customized patterned fixture which corresponds to the first contact pressure variation data; pre-compressing the a second bipolar plate with the customized patterned fixture; and obtaining second contact pressure variation data of the at least two metal bead regions stamped in the second bipolar plate to determine if contact pressure variation between the at least two metal bead regions has been reduced.

2. The method for manufacturing a bipolar plate as defined in claim 1 further comprising the step of providing a modified customized patterned fixture device which corresponds to the second contact pressure variation data when the contact pressure variation of the bipolar plate falls outside of a pre-determined range.

3. The method for manufacturing a bipolar plate as defined in claim 1 wherein the steps of obtaining first and second contact pressure variation data implements a pressure measurement film.

4. The method for manufacturing a bipolar plate as defined in claim 1 wherein the customized patterned fixture includes at least one of an embossment or a recess which corresponds to the first contact pressure variation data.

5. The method for manufacturing a bipolar plate as defined in claim 4 where an embossment is defined in the customized patterned fixture in a high pressure region.

6. The method for manufacturing a bipolar plate as defined in claim 4 where a recess is defined in the customized patterned fixture in a low pressure region.

7. The method for manufacturing a bipolar plate as defined in claim 4 wherein the customized patterned fixture is configured for use in mass production.

8. A method for manufacturing a stamped product comprising the steps of: stamping sheet metal within a stamping press system and forming a plurality of stamped members; assembling the plurality of formed members to form a plurality of stamped products; pre-compressing a first stamped product between a pair of flat fixture plates; obtaining first contact pressure variation data of at least two metal bead regions stamped in the first stamped product; providing a customized patterned fixture which corresponds to the first contact pressure variation data; pre-compressing a second stamped product with the customized patterned fixture; and obtaining second contact pressure variation data of at least two metal bead regions in the second stamped product to determine if contact pressure variation between the at least two metal bead regions has been reduced.

9. The method for manufacturing a stamped product as defined in claim 8 further comprising the step of providing a modified customized patterned fixture device which corresponds to the second contact pressure variation data when the contact pressure variation of the first stamped product has not been reduced to acceptable levels

10. The method for manufacturing a stamped product as defined in claim 8 wherein the steps of obtaining first and second contact pressure variation data implements a pressure measurement film.

11. The method for manufacturing a stamped product as defined in claim 8 wherein the customized patterned fixture includes at least one of an embossment or a recess which corresponds to the first contact pressure measurement data.

12. The method for manufacturing a stamped product as defined in claim 10 where an embossment is defined in the customized patterned fixture in a high pressure region.

13. The method for manufacturing a stamped product as defined in claim 10 where a recess is defined in the customized patterned fixture in a low pressure region.

14. The method for manufacturing a stamped product as defined in claim 8 wherein the customized patterned fixture is configured for use in mass production.

15. The method for manufacturing a stamped product as defined in claim 8 wherein the customized patterned fixture is configured for use in mass production.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and other features and advantages of the present disclosure will be apparent from the following detailed description, best mode, claims, and accompanying drawings in which:

[0020] FIG. 1 illustrates an example stamped member wherein the stamped product is in the form of a bipolar plate.

[0021] FIG. 2 flowchart of an example, non-limiting manufacturing method of the present disclosure.

[0022] FIG. 3 illustrates a schematic flat pre-compression fixture.

[0023] FIG. 4 illustrates an example, non-limiting schematic patterned fixture having one embossment.

[0024] FIG. 5 illustrates an example, non-limiting schematic patterned fixture having one recess.

[0025] FIG. 6 illustrates an example, non-limiting schematic patterned fixture having both an embossment and a recess.

[0026] FIG. 7 illustrates a flow chart of an example process for providing a patterned fixture based on contact pressure measurements from a stamped member or bipolar plate.

[0027] Like reference numerals refer to like parts throughout the description of several views of the drawings.

DETAILED DESCRIPTION

[0028] Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present disclosure, which constitute the best modes of practicing the present disclosure presently known to the inventors. The figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the present disclosure that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the present disclosure and/or as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

[0029] Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word about in describing the broadest scope of the present disclosure. Practice within the numerical limits stated is generally preferred. Also, unless expressly stated to the contrary: percent, parts of, and ratio values are by weight; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the present disclosure implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.

[0030] It is also to be understood that this present disclosure is not limited to the specific embodiments and methods described below, as specific components and/or conditions may, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present disclosure and is not intended to be limiting in any manner.

[0031] It must also be noted that, as used in the specification and the appended claims, the singular form a, an, and the comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

[0032] The term comprising is synonymous with including, having, containing, or characterized by. These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps.

[0033] The phrase consisting of excludes any element, step, or ingredient not specified in the claim. When this phrase appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0034] The phrase consisting essentially of limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.

[0035] The terms comprising, consisting of, and consisting essentially of can be alternatively used. Where one of these three terms is used, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

[0036] Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this present disclosure pertains.

[0037] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

[0038] With reference to FIG. 2, a flowchart is provided which shows an example non-limiting method 10 of the present disclosure. As shown, the method 10 for manufacturing a bipolar plate 6 (shown in FIG. 1) (or stamped product 4) includes the steps of: (1) stamping a piece of sheet metal 8 within a stamping press system to form a plurality of stamped members; 12 (2) assembling the plurality of stamped members to form a plurality of bipolar plates; step 14 (2) pre-compressing a first bipolar plate between a pair of flat fixture plates; 16 (3) obtaining first contact pressure variation data of at least two metal bead regions 72, 74; 18 (4) providing a customized patterned fixture 28 which corresponds to the first contact pressure variation data; 20 (5) pre-compressing a second bipolar plate with the customized patterned fixture 28; 22 and (6) obtaining second contact pressure variation data of the at least two metal bead regions 72, 74 stamped in the second bipolar plate 6 or stamped product 4 to determine if contact pressure variation between the at least two metal bead regions 72, 74 of the second bipolar plate has been reduced. 24

[0039] It is understood that the step (element 14 in FIG. 2) of stamping the piece of sheet metal 8 may include stamping the piece of sheet metal 8 with at least one die to define a flat land 50, a first sidewall 52, a second sidewall 54 and a first/second sidewall depth/height (element 60 in FIG. 1) for at least one metal bead 58. The step of stamping sheet metal 8 to form the metal bead 58 in each stamped sheet 5 results in the formation of a plurality of stamped members 5, the stamped members 5 or sheet metal 8 may be assembled together to form a plurality of bipolar plates 8 or stamped products 4. A first bipolar plate 6 may then be pre-compressed between a pair of flat dies (element 40 shown in FIG. 3) in order to reduce metal bead 58 and microseal 68 tolerances due to manufacturing. Pre-compression between the flat dies 40 also may reduce creep variation of softgoods such as the subgasket, microseal and adhesive. Pre-compression also enforces the metal bead 58 such that the metal bead 58 will tend to behave elastically. Moreover, pre-compression also enables easy calculation of the stack load and set-up given that the mechanical behavior of the entire stack of bipolar plates 6 is stabilized after undergoing pre-compression.

[0040] As shown in FIG. 2, the step 18 of obtaining the first contact pressure variation data between at least two metal bead regions 72, 74 (FIG. 1) in the first bipolar plate 6 may, but not necessarily, implement the use of a pressure measurement film 56 (FIG. 1) such as, but not limited to Fuji film. In one non-limiting example, the pressure measurement film 56 (FIG. 1) may be disposed between the bipolar plate 6 and two flat compression plates which exert pressure on the bipolar plate 6 and the pressure measurement film 56 (FIG. 1). The pressure measurement film 56 (FIG. 1) may include one layer of micro-encapsulated color forming material and another layer of color-developing material. Thus, when pressure is applied, the microcapsules are broken such that color forming material reacts with the color developing material causing colored patches to form on the film in high pressure regions 34such as certain metal bead regions 72, 74.

[0041] With reference to FIG. 7, the process 80 of correlating the pressure measurements to a customized patterned fixture 28 is illustrated in a flow chart. In one example pressure measurement test which uses pressure measurement film 56 (FIG. 1), the level/amount of color exposed at different regions of the bipolar plate 6 (or stamped product 4) (through the use of pressure measurement film 56 (FIG. 1)) may identify any contact pressure variations across the surface of the bipolar plate 6, 6 (or stamped product 4). To the extent excessively high pressure regions 34 (FIG. 1) and excessively low pressure region 38 (FIG. 1) are identified in the plate 6, 6 or stamped product 4 (element 82 in FIG. 7) via the pressure measurement film 56 (FIG. 1)resulting in significant pressure variations, a customized patterned fixture 28 (FIGS. 4, 6) is provided where embossment(s) 30 are defined in the high pressure regions 34 of the fixture (FIG. 4) which correspond to high pressure regions 34 found in the plate 6 or stamped product 4 (FIG. 1) such that the added embossment(s) 30 compress metal bead(s) 58 more thereby reducing the height 61 (FIG. 4) of the metal bead(s) 58. The reduced height 61 of the beads 58 accordingly reduces the contact pressure in the identified high pressure region 34. Similarly, the pressure measurement film regions with little to no color exposed (after compression) may identify (element 86 in FIG. 7) at least one low pressure region (example element 38 in FIG. 1) on the bipolar plate 6, 6 or stamped product 4. Accordingly, the customized patterned fixture 28, 29 should also include recesses 32 or slots in region(s) 38 of the customized patterned fixture 28, 29 which correspond to the low pressure regions 38 such that the customized patterned fixture 28, 29 will not further deform the low pressure metal bead region 38. It is understood that where the pressure measurement film shows normal contact pressure in specific regions (via the amount of color exposed in the chosen film (step 84 in FIG. 7), the customized pattern fixture 28 is flat (element 85 in FIG. 7) such that neither a recess nor an embossment is implemented in normal contact pressure regions,

[0042] Referring back to FIG. 2, once all of the embossments 30 and/or recesses 32 are defined in the customized patterned fixture 28, a second bipolar plate 6 may be pre-compressed by the customized patterned fixture 28 which deforms the high pressure metal bead region(s) 34 such that the height(s) (example element 61 in FIG. 4) are reduced and which does not further deform the low pressure metal bead region(s) 38 thereby reducing contact pressure variation across the various areas of the stamped product 4 or second bipolar plate 6. After the stamped product 4 or bipolar plate 6 has been pre-compressed by the customized patterned fixture 28, a second measurement (element 24 in FIG. 2) is taken where contact pressure is measured over the various regions of the second stamped product 4 or bipolar plate 6. In the event that pressure variation across the stamped product 8/bipolar plate 6 falls within acceptable limits, then the customized patterned fixture 28 may be implemented for use in mass production. (Element 26 in FIG. 2)

[0043] However, in the event pressure variation across the second stamped product 4 or second bipolar plate 6 falls outside the scope of acceptable limits (pressure variation is too high), then the customized patterned fixture 28 design may be modified to: (1) add additional embossments 30 in remaining high pressure regions 34 or increase the size of existing embossments 30 in regions 34 which still exhibit high levels of contact pressure; (element 83 in FIG. 7) (2) add additional recesses 32 or increase the size of recesses 32 in regions 38 which still exhibit low levels of contact pressure; (element 87 in FIG, 7).

[0044] Referring back to FIG. 1, the modified customized patterned fixture 29 then pre-compresses a third bipolar plate 6 (or third stamped product 4)to further reduce the contact pressure variation across the bipolar plate 6/stamped product 4 so that the variation falls within a pre-determined (acceptable) range. Similarly, contact pressure measurements are again taken across the bipolar plate 6/stamped product 4 as previously described. In the event that pressure variation across the bipolar plate 6/stamped product 4 falls within an acceptable predetermined range, then the modified customized patterned fixture 29 may be implemented for use in mass production. However, in the event pressure variation across the bipolar plate 6/stamped product 4 falls outside the scope of acceptable predetermined range (pressure variation is too high), then modified customized patterned fixture 29 is revised again as previously described until contact pressure variation across the bipolar plate 6/stamped sheet metal 8 falls within acceptable limits.

[0045] Accordingly, the customized patterned fixture 28 includes at least one of an embossment 30 or a recess 32 (or both) which corresponds to data derived from the first contact pressure measurement. Similarly, the modified customized patterned fixture 29 (if needed) includes at least one embossment 30 or recess 32 as previously described which corresponds to the second contact pressure variation data when the contact pressure variation of the second bipolar plate 6 or second stamped product 4 has not been reduced via the initial stamping with the customized patterned fixture 28. As noted, the (modified) customized patterned fixture 28, 29 which tunes the bipolar plates 6 or second stamped products 4 to fall within acceptable contact pressure variation limits is configured for later use in mass production.

[0046] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.