CN101997122A

CN101997122A - Bipolar plate and method for its production

Info

Publication number: CN101997122A
Application number: CN2010102444954A
Authority: CN
Inventors: 贝恩德·高格勒; 克劳迪娅·孔茨
Original assignee: Reinz Dichtungs GmbH
Current assignee: Reinz Dichtungs GmbH
Priority date: 2009-08-03
Filing date: 2010-08-02
Publication date: 2011-03-30
Anticipated expiration: 2030-08-02
Also published as: CN101997122B; CA2711210A1; DE202010010972U1; CA2711210C; DE102009036039B4; DE102009036039A1

Abstract

The present invention relates to a bipolar plate as well as to a method for its production. The bipolar plate preferably comprises at least two layers with at least two layers comprising each at least a first and a second indentation/protrusion, where the first indentation/protrusion of the first layer and the first indentation/protrusion of the second layer in a completely positioned state of the layers engage with each other and contact each other in the plane E1 with positive fit. The second indentation/protrusion of the first layer and the second indentation/protrusion of the second layer engage with each other in a completely positioned state of the layers and contact each other in the plane E2 only in sections in at least two sections. The contact portions are arranged on both sides of a virtual straight line, which extends in the main direction of the indentation/protrusion in the second layer. No positive fit between the interlocking second indentations/protrusions results in the area of the second contact area. The invention allows a fast, cost efficient and tailored production of bipolar plates.

Description

Bipolar plates and manufacture method thereof

Technical field

The method that the present invention relates to bipolar plates and be used to make this bipolar plates.

Background technology

Bipolar plates according to the present invention can be used in the electro-chemical systems, for example is used in the fuel cell system or is used in the electrolyzer.The known electro-chemical systems that has some types to use the electro-chemical cell duplexer, this duplexer has a plurality of electro-chemical cells of layering, and each is separated described electro-chemical cell by bipolar plates.Bipolar plates has following some functions:

-be electrically connected the electrode of each electro-chemical cell, and electric current is guided to adjacent battery (battery is connected in series);

-with medium or reactant for example water and gas offer battery, and remove the reacting gas that in battery, produces by corresponding distribution structure (being so-called flow field);

-be transmitted in the heat that produces in the electro-chemical cell; And

-about each other and the cooling duct that seals different types of medium and flow field with respect to the external world.

For very big plant-scale expection was used, it was very important can producing a large amount of high-quality bipolar plates at low cost.In this case, the variable quantity that does not exceed dimensional tolerance is very important because otherwise may cause functional fault, even with security-related fault.This is for the plurality of layers of double pole plate particular importance of welding.

Up to the present, also use location hole to guarantee that each layer is about accurately locating each other.Practice shows, guaranteeing that described layer not enough about mutually positioning accuracy and reproducibility under the situation that at least two bipolar plates form simultaneously about these location holes of accurate relative positioning each other and other through hole and with the cutting of external margin.Especially, may cause skew between the channel geometries in flow field of each layer.Under the situation of extremely skew, carry out the welding of bipolar plates in the zone that bipolar plates does not contact each other during the welding step of bipolar plates, this can be owing to burning cause the breaking-up of corresponding zone.

Summary of the invention

Therefore, the purpose of this invention is to provide the manufacture method of plurality of layers of double pole plate and plurality of layers of double pole plate, this manufacture method allows to make the plurality of layers of double pole plate on a large scale with high-quality and low cost.

This purpose is by realizing according to described bipolar plates of independent claims and method.

First embodiment that is used for the method for production plurality of layers of double pole plate proposes: form at least the first recess/projection and second recess/projection in every layer of at least two layers, and described layer is located in stacked mode.Under described two layers state stacked on top of each other fully, first recess/projection of ground floor is engaged with each other with the first recess/projection of the second layer and contacts with profile lock mode (thereby with embedded mode) in the E1 of plane by setting up first contact area.Second recess/projection of ground floor is engaged with each other with the second recess/projection of the second layer simultaneously, but only partly contacts with each other in the E2 of plane by forming second contact area.Its contact site is arranged in the both sides of a virtual line, and this virtual line is extending on the principal direction long extension, this second recess/projection of second recess/projection of the second layer.In the E2 of this plane, between the second recess/projection of second recess/projection of ground floor and the second layer, there be not airtight embedded the connection.Described at least two layers are located in nested mode, and wherein recess/the projection of at least one layer is fixed in the complementary recess/projection of fixture, and described at least two layers are bonded to each other there by adhint.

Because this layout, under positioning states fully, thereby described layer and then the cloth before it is combined deposit, between described two layers, can not have translation along the direction of passing the virtual line of two contact positions.But, can be between described layer adjusting in the limit in the dimension scale of corresponding second recess/projection on the direction vertical with this virtual line.

Bipolar plates presents the channel design with recess and/or protuberance usually.This channel design limits the flow field.Form at two layers under the situation of separator and cooling system, these two layers all can be by structuring.Form at three layers under the situation of separator and cooling system, at least two outer meetings are by structuring.Internal layer can be by structuring, but this not necessarily.The recess and/or the projection that form these recesses of channel design of described layer and/or protuberance and the location that is used for determining described layer have nothing to do.This is meant that recess/projection preferably is positioned at the outside of channel design.But the reason for saving the space preferably can be arranged in them between the channel design.

Preferably, in identical program step, in described two layers, form the recess and/or the protuberance of passage at least with recess/projection.It is parallel that the orientation of channel design makes that usually its principal direction and recess/projection allows to carry out the direction of limited adjustment between the layer of bipolar plates.Each second recess/projection is predetermined before it is molded with respect to the position of channel design in two layers.This prevents to form in reproducible mode the skew perpendicular to its principal direction between the passage of equivalent layer when initial.

Term under the background of the present invention " recess/projection " is used for the part of the layer of bipolar plates, and this part is from the planar projection of equivalent layer.Regard this projection as recess still be that projection depends on viewing angle.If use complementary term " projection/recess " here, then this is in order to emphasize in the other direction.

Second embodiment that is used for the method for production plurality of layers of double pole plate proposes: at least two layers, form first, second and the 3rd recess/projection at least, and described layer is located in stacked mode.Under complete positioning states, each first recess/projection of the ground floor and the second layer is engaged with each other by forming first contact area, each second recess/projection of the ground floor and the second layer is engaged with each other by forming second contact area, and each the 3rd recess/projection of the ground floor and the second layer is engaged with each other by forming the 3rd contact area.Like this, ground floor and the second layer in plane E2, E3 and E4 each other only part contact, promptly contact, and can between the ground floor and the second layer, not form embedded connection with at least two contacts site.These contacts site so that the mode that they extend in the both sides of the virtual line that extends along the principal direction of the corresponding second recess/projection of the second layer respectively in plane E2, E3 and E4 arrange.These virtual lines that pass first contact area and second contact area extend usually each other substantially parallelly.In the present invention " substantially parallel " expression angle-10 ° and+10 ° between.The virtual line that passes the 3rd contact area is substantially perpendicular to preceding two virtual lines and extends.In the present invention, " perpendicular " expression angle is between 80 ° and 100 °.

Described at least two layers are by being connected to each other in conjunction with (being also referred to as bonding here), and wherein, the recess/projection of at least one layer is fixed in the complementary projection/recess of fixture, to guarantee that described layer is about accurately locating each other.In the present invention,, brazing gluing, soldering and welding, especially laser welding in conjunction with comprising.

As a result, the limited adjustable that provides of the parallel orientation of cardinal principle that utilizes above-mentioned virtual line by two contact areas is distributed on the whole area of bipolar plates in the mode of rule more.Particularly utilize the layout placed in the middle of another contact site, the contact site that the virtual line perpendicular is arranged is in the adjustment of the both sides of this contact area realization to two layers shaping tolerance relative to each other.Even lack forming accuracy, also provide to be used for enough degrees of freedom that described layer is relative to each other adjusted, this makes still determines described layer location relative to each other exactly.This scheme especially has advantage for almost square flow field regions.

In this embodiment still, preferably, in identical program step, in described two layers, form to form the recess and/or the protuberance of passage at least with recess/projection, between the contact site of channel design and each layer, to provide preset distance.

In above-mentioned two embodiment, if at least one recess/projection has the through hole that the centering bolt of fixture can pass through, it is favourable then locating for optimization before described layer connects.

Be used for comprising gluing described layer method for optimizing connected to one another and welding, most preferably laser welding.Bipolar plates and each layer thereof preferably include metal respectively, and most preferably steel perhaps is made of metal.This allows them to be shaped by mold pressing, deep draw, hydroforming, the adiabatic shaping (such as forging and high energy rate forming) or roll forming.

Plane E1 and E2 or E2, E3 and E4 be respectively the stacked direction that is substantially perpendicular to fuel cell layered body in the respective planes of the contact site between two layers towards the plane.The plane E that these planes E1 and E2 or E2, E3 and E4 are parallel to bipolar plates respectively extends, and this bipolar plates except that the required structure of its function is normally flat; Plane E is restricted between two skins of bipolar plates and medially extends basically.Plane E1 on the one hand and E2 and on the other hand plane E2, E3 and E4 are parallel to each other, just realize the situation of contact in different contacts site in the mode of skew.But they also can be identical, and this comes from and does not have such skew.

First embodiment according to bipolar plates of the present invention proposes: this bipolar plates is made of two layers with channel design at least, wherein at least two layers have at least the first recess/projection and second recess/projection separately, wherein, first recess/projection of ground floor is engaged with each other under the complete positioning states of described layer with first recess/projection of the second layer, and contacts with each other with profile lock mode (thereby utilizing embedded mode) in the E1 of plane by forming first contact area.On the contrary, second recess/projection of ground floor only partly contacts with each other in the E2 of plane when forming second contact area with second recess/projection of the second layer, and just (being the point-like in some cases even only) part along at least two weak points contacts with each other.These contacts site are positioned at along the both sides of the virtual line of the principal spread direction extension of second recess/projection of the second layer.But the segment bounds contact between the second recess/projection of the joint of the ground floor and the second layer forms the embedded connection of described layer separately in the E2 of plane.On the contrary, on the direction of above-mentioned virtual line, be parallel to plane E2 and can carry out limited translation adjustment.But the mutual effect between two contact areas prevents rotation adjustment.

This makes two layers utilize being used to adjust the finite degrees of freedom of purpose of described layer and about locating exactly each other, promptly locatees exactly each other along the direction of the virtual line that is substantially perpendicular to two contacts site that pass second contact area.

Should be appreciated that bipolar plates generally includes channel design.Especially at the outer surface of bipolar plates, these channel designs provide the guiding to reaction medium (for example be molecular hydrogen on the one hand, and be air/oxygen on the other hand), and the guiding to coolant especially is provided between layer.For this reason, channel designs two adjacent bipolar plates layers, on surfaces opposite to each other form the flow field, are generally used for coolant.Similarly, the corresponding offside at each bipolar flaggy forms flow field, the distribution of this flow field realization response thing and the taking-up of product.Utilize metal double polar plates, normally complementary in the structure of the both sides of layer, the projection that this means upside causes the depression of downside.Except the continuous channel design of parallel and/or snakelike layout, allow between virtual parallel streamline, to realize that other distribution structure that shifts also is feasible.The latter is also referred to as channel design in the present invention.

For metal double polar plates, the location of using the positioning module splenium to carry out described layer is especially favourable, and reason is that the layer of bipolar plates often has the form tolerance that is derived from forming technology, particularly because the form tolerance that resilience causes.Form channel design and recess/projection simultaneously and can between these structures, realize predictable, reproducible distance.Therefore, the present invention allows to make each layer of bipolar plates to minimize about each other skew, thereby the accurate location of realizing (preferably passing through mold pressing) channel design of each layer, especially also in welding equipment (for example laser welding apparatus), make simultaneously the combination of described layer.This obtains following advantage: welding better and faster; Because the location is better, the quantity of the defective part during when welding and other process reduces.This allows the tolerance of total cutting of increase flaggy.Conversely, particularly owing to can adopt simpler cutting method, for example punching has realized the cost reduction, and to quality without any influence.

In order to prevent that the plurality of layers of double pole plate from expanding, suggestion is welded to one another at least two outermost layers of bipolar plates, particularly welds by laser welding.But, when the correct part of the meticulous and/or little channel design of welding, should be noted that.This is of crucial importance, because the controlled flow of the coolant between the layer of this decision sealing and bipolar plates.Emphasize that once more the welding of the layer of bipolar plates is not merely carried out along the outer rim of plate, but also carries out in the portion zone within it, just between different channel designs, carry out, and,, need the split hair to each other location of bipolar flaggy particularly for the latter.

But another alternative scheme of the present invention proposes: bipolar plates comprises at least two layers, wherein at least two layers each have at least first, second and the 3rd recess/projection respectively.First recess of the ground floor and the second layer/projection is engaged with each other respectively, forms first contact area simultaneously.Second recess of the ground floor and the second layer/projection is engaged with each other respectively, forms second contact area simultaneously.The 3rd recess of the ground floor and the second layer/projection is engaged with each other respectively, forms the 3rd contact area simultaneously.Described joint always appears under the complete arrangement states.Corresponding recess/projection only partly contacts with each other in plane E2, E3 and E4.The contact site of contact area is to being placed among plane E2, E3 and the E4, respectively in the both sides of the virtual line that extends along the principal direction of the respective notches/projection in the second layer.About first contact site and second contact site, these virtual lines extend in parallel to each other, extend and be substantially perpendicular to preceding two virtual lines along the virtual line that the principal direction of the 3rd contact site is extended.

Hereinafter, preferred embodiment according to bipolar plates of the present invention is described in a simplified manner.

An embodiment proposes the respective notches/projection of the recess/protruding self-centering of ground floor to the second layer.Because described layer needn't align to plate so this makes about making self centering each other, needn't align to plate particularly on its short transverse, and then on the stacked direction of fuel cell layered body.

Another advantageous embodiment of the present invention requires the first recess/projection and/or the second recess/projection of the ground floor and/or the second layer to comprise through hole.Preferred placed in the middle layout of these through holes.It is best in two layers the hole being set all.Such through hole allows set bolt or centering bolt (for example set bolt of fixture or centering bolt) engagement.On the other hand, have the hole of different size or the hole in layer only and allow to realize visual control the correct combination of layer.

Another advantageous embodiment proposes, and the ground floor that is engaged with each other and the recess/projection of the second layer have round-shaped.Similarly, also can propose, second recess/projection of ground floor also is circular, and second recess of the second layer/projection is oval-shaped or have the polygonal shape of fillet, but is not circular.

Usually, recess/projection can have all shapes that can produce by mold pressing, and owing to make and processing, the shape of band fillet is preferred.The geometry of the geometry of fixture and recess/projection is mated very important mutually.Correspondingly, in the present invention, ellipse also comprises avette and fillet polygon, but clear and definite do not comprise round-shaped.

Another advantageous embodiment proposes, and at least one layer comprises channel design, and the longitudinal direction of second recess/projection is arranged to and is parallel to this channel design.This has determined may be because for example heat or manufacturing (the particularly different resiliences of each layer after mold pressing) cause under the situation of extension parallel offset along channel design connected to one another at plate.This permission " deepest point " of passage in two layers always arranged in stacked mode, and desired zone is in contact with one another.This is particularly advantageous during welding, particularly laser welding, because can prevent because the overheated burning that causes damages.

Another advantageous embodiment proposes, and the coning angle that the recess/projection of ground floor has than the complementary recess/projection of the second layer more tilts or littler coning angle.This allows to realize linear circumferential contact between recess/projection, and this has caused enough surface pressings.By the differing heights of the recess/projection in adjacent layer, this effect is further increased.

Hereinafter, described particularly preferred embodiment of the present invention, yet these descriptions should not be understood that to limit the present invention with different slightly words.

For realizing that bipolar plates about each other accurate location, forms the mold pressing portion of taper in layer.Depend on viewing angle, can think that these mold pressing portions are recess or projection.If for example have two circular mode spleniums in the face of the bipolar flaggy (anode-side layer) of anode-side, and the bipolar flaggy of faces cathode side (cathode side layer) has circular mode splenium and elliptical mode splenium, then is favourable.These positioning module spleniums can have and for example allow the anode-side layer by nested shape and size to the cathode side layer, and the cone of mold pressing portion allows to realize the centering of described layer about each other profile locking.The advantage of elliptical mode splenium is derived from not overdetermination (over-determined) of layer system, and this layer system of overdetermination does not allow to be implemented in the adjustment between anode-side layer and the cathode side layer.Therefore, extending if the longest extension of principal direction and then elliptical mode splenium is parallel to the principal direction of the passage in flow field, then is favourable.This prevents the biasing on the y direction, therefore prevents the biasing perpendicular to channel design.

Another characteristic of positioning module splenium is that the positioning module splenium also can be used in the profile lock in place in equipment, and this equipment for example is welding equipment.For identical as mentioned above reason, the retainer in this equipment preferably has compares shape complementary but that increase slightly with the corresponding recess/projection of bipolar flaggy.Therefore, if use oval positioning module splenium, then retainer also has elliptical shape, but its size is greater than the size of the mold pressing portion in the equivalent layer, for example referring to the cross section C-C among Fig. 3 e.The circular retainer that size increases is used for circular positioning module splenium.Realize for allowing the rough pre-centering of each layer in this equipment, hole and oval hole are set in the centre of positioning module splenium and corresponding retainer pin are set in this equipment or the centering bolt can be favourable.This pre-centering of being undertaken by the retainer pin makes described layer insert in the retainer of this equipment smooth-goingly.

There is multiple different selection in design for the positioning module splenium of the correspondence in the equivalent layer.On the one hand, can in two layers, form the projection of protruding with respect to all the other planes of layer, and engage in the recess of the downside of the projection of projection in being formed at the upper strata in the layer under being arranged in another layer.Yet, when considering other structure division of each bipolar plates or bipolar flaggy, usually can not form only in one direction projection of its whole height, because at that rate, projection can for example protrude into and be used to make described layer about sealing each other on the required crimping, thereby can hinder the sealing of described plate.In this case, suggestion all forms the recess with larger diameter in two layers, and respectively in the surface of these recesses mold pressing form projection.For forming projection, the height of recess is less than the total height of actual projection.This allows the height of recess/projection is dispensed to the both sides on the plane of each bipolar plates.In a word, symmetrical highly distribution and the distribution of asymmetric height about both sides all is possible.

Can select the design of positioning module splenium according to the mode that makes a layer have more a cone that tilts than another layer.In addition, advantageously in two layers, have the mold pressing portion of differing heights, make described layer only in corresponding cone side, in the contact site, either partially or fully on periphery, be in contact with one another.

In addition, it is useful that the circular or oval-shaped retainer of equipment is provided with rounding in its open side, and this rounding bears the inclined-plane of the outer circle cone of bipolar plates.Yet, during locating, need to apply enough power to realize having the centering of embedded connection.

As record already, bipolar plates according to the present invention comprises at least two layers, but can comprise more layer.This is especially favourable under the situation of the inboard channeling conduct of bipolar plates at coolant.Particularly for constitute the 3rd layer not by structurized intermediate layer, advantageously the 3rd layer is integrated in the bipolar plates as follows: the 3rd layer cut in the zone of outer field recess/projection, makes an outer field recess/projection can engage another outer field projection/recess when passing otch.

For the bipolar plates that has more than two layers, layer that also may this bipolar plates is arranged in pairs in the mode identical with the mode of above describing about two-ply.By in x-y plane (more precisely being plane E1), causing the positioning module splenium of embedded connection, similarly also can in all layers, provide corresponding recess/projection in same position, need be about adjacent paired layer and arranged offset and in its each contact plane E2, E3 or E4, do not form the positioning module splenium of embedded connection.This layout is applicable to structurized plate, therefore is applicable to the intermediate layer that is molded, because the positioning module splenium can form with remaining structure.But this layout also is applicable to non-structured intermediate layer.

Description of drawings

Hereinafter, based on different accompanying drawings the present invention is described.Identical reference marker is represented identical parts.

In the accompanying drawings:

Fig. 1 a to Fig. 1 d is the exemplary configurations that comprises the electro-chemical cell duplexer of at least one bipolar plates;

Fig. 2 is a layer according to bipolar plates of the present invention;

Fig. 3 a to Fig. 3 g is view, cross section and the more details according to first embodiment of bipolar plates of the present invention;

Fig. 4 a to Fig. 4 c is vertical view and the cross section according to second embodiment of bipolar plates of the present invention;

Fig. 5 a to Fig. 5 h is the different vertical view of contact site;

Fig. 6 is the sectional view according to the another embodiment of bipolar plates of the present invention;

Fig. 7 is the sectional view according to the contact site of the another embodiment of three layers of bipolar plates of the present invention; And

Fig. 8 is about the details according to the laser welding of bipolar plates of the present invention.

Embodiment

Fig. 1 a and Fig. 1 d illustrate the structure of cell of fuel cell 7.A plurality of such cell of fuel cell 7 form fuel-cell device 8, and this fuel-cell device is stacked with stacked direction z between

end plate

70 and 71, shown in Fig. 1 c.Fig. 1 b illustrates several cell of fuel cell that is laminated to each other 7, but does not have end plate.In Fig. 1 a and Fig. 1 d, see cell of fuel cell 7 in the sectional view in exploded view and plane x-z respectively with its normal elements.This cell of fuel cell 7 for example comprises polymer film 9, and this polymer film is provided with catalyst layer among the 9a of heart zone therein on two surfaces.Cell of fuel cell 7 comprises two

bipolar plates

1 and 1 ^*, the polymer film of layout coating between these two bipolar plates.In addition, in each

bipolar plates

1,1 ^*And be furnished with gas diffusion layers 10 in the zone between the polymer film 9 of coating.

Bipolar plates

1,1 ^*Thereby comprise in the mode of sealing and surround crimping (bead) 4a that the flow field surrounds channel design 4.In addition, another crimping 4a is shown, this another crimping 4a makes medium dredge sealing between the unit 7 ' that repeats.In the accompanying drawing below, omitted the expression of seal member for clarity.

Distinguish following term in this application:

-actual fuel cell is defined as the polymer film 9 of first gas diffusion layers 10, coating and the zoarium of second gas diffusion layers 10;

-cell of fuel cell 7 comprises: the anode-side layer 2 of bipolar plates 1, and as the fuel cell and second bipolar plates 1 that in preamble, defines ^* Cathode side layer 3, and bipolar plates 1 other the layer (when needed).

This expression bipolar plates 1 is always distributed between two cell of fuel cell 7.Need this term " cell of fuel cell " and so-called repetitive 7 ' are distinguished, repetitive 7 ' comprises complete bipolar plates 1 and according to the fuel cell of above definition.Fig. 1 d points out that further described layer is welded to one another along periphery at least in the zone of crimping 4a, referring to weld seam 11.In this case, be apparent that compare with channel design 4, seal bead 4a has the bigger mold pressing degree of depth.Fig. 1 d further illustrates the different compartments of channel design 4: at

dorsad layer

2,3 lip-deep

reactant channel

41,42 each other, and the passage that is used for cooling agent 43 between

layer

2,3, described layer is partly contact each other.Expression in Fig. 1 d relates to the non-compressed state of fuel cell.

Hereinafter, target is by the structure of example explanation bipolar plates 1 and the method for producing this bipolar plates.

Fig. 2 illustrates a layer 3 according to bipolar plates of the present invention.In the example shown, metal level 3 has continuous, straight channel design 4, and channel design 4 has some parallel passages, and the flow field is five times of scope on the y direction in the scope on the x direction.Metal level 3 also illustrates circular recess 3a and oval recess 3b.The circular recess 3a heart therein is provided with circular port, and oval recess 3b illustrates the slotted eye at the center of being arranged in.Bearing of trend 5, thereby, therefore be parallel to the direction that fluid is dredged for the virtual line on the direction of the longest extension of oval recess is arranged to the extension that is parallel to channel design 4.This expression channel design guides fluid (this fluid is the coolant media in the inboard of following bipolar plates, the perhaps medium on the outer surface of following bipolar plates) exactly on this direction.

Layer 3 shown in Figure 2 is connected at least one other layer to form bipolar plates.These layers mutually combine by laser welding, not only the external margin in bipolar plates carries out laser welding, and, under the pressure of the increase of the cooling agent of bipolar plates inboard, expand to prevent bipolar plates at least in the part of central area, just carry out laser welding in some contact areas in the flow field of bipolar plates.For reliable accurate welding is provided, it is favourable that the bearing of trend 5 of oval recess is parallel to the channel design extension.

Fig. 3 a illustrates the vertical view according to the bipolar plates 1 of combination of the present invention.Bipolar plates is made of at least two

layers

2 and 3, and described at least two layers are by the laser welding combination, as

weld seam

11,11 ' and 11 " shown in.Laser weld lines 11 constitutes solid line.Correspondingly weld with sealing means in the zone that channel design (being supplied to and taking out line interruption when needed) is surrounded in this expression.In addition, the zone of projection and recess (which is considered to projection or recess depends on viewing angle, referring to

reference marker

2a and 2b) is bonded to each other, referring to dotted line 11 '.In addition, in the zone in flow field, by means of the straight bead of segmentation, two layers of bipolar plates 1 also are connected to each other, and the position of weld seam is for example by arrow 11 " illustrate.

This illustrates the ground floor 2 on top, under it, only can partly, promptly identify layer 3 in the zone in hole.In the layer 3 of bottom, the diameter in the hole in the zone of recess/projection is less, and this provides little visible part, as can finding out from the upper right portion of Fig. 3 a.Whether this permission (by vision or automation inspection) check has assembled correct layer in correct mode.

Hereinafter especially also pay close attention to recess/projection of

contact area

23a and 23b by means of cross-sectional views B-B (seeing Fig. 3 b), C-C and D-D (seeing Fig. 3 a, Fig. 3 e and Fig. 3 f).Schematic plan in the corresponding shearing of region D 1 shown in Fig. 3 c and Fig. 3 g and D2.In addition, Fig. 3 d has illustrated the relation of the angle of recess/projection shown in Fig. 3 b.In this case, in fact the parts of lower floor are covered by the upper strata, are sightless therefore, and for example oval-shaped recess/projection is illustrated by solid line.Fig. 4 a also is a kindred circumstances.

Fig. 3 a illustrates, and the contact area 23a place in two

layers

2 and 3 is provided with circular recess/protruding 2a and 3a.On the contrary, contact area 23b illustrate layer in 2 circular recess/protruding 2b and the oval recess/protruding 3b in the layer 3.The recess of these interlockings/protruding 2b and 3b illustrate two contact site 30b and 31b.Compare with the circular protrusions 2b in the layer 2, corresponding

contact site

30b and 31b only extend in the extremely short part of periphery, and it almost only is a

shape.Contact site

30b and 31b are placed on the round relative side and toward each other.The direction that the virtual line indication of the central point of corresponding contact site 30b of process and 31b can not be moved.This direction is substantially perpendicular to the principal direction of channel design 4 and the direction of weld seam 11 '.Yet, on direction perpendicular to this virtual line, along line 5b, two layers can both be in limited scope about moving each other, this allow to realize limited tolerance adjustment or since the extension that heat causes cause or because the relatively moving that forming process causes along the channel design of two layers.

Fig. 3 b illustrates the bipolar plates according to Fig. 3 a, and this bipolar plates is introduced in the fixture of retainer 6c, for example welder of fixture 6.This fixture also presents centering bolt 6a and rounding 6b.This illustrates the detailed view according to section B-B, wherein, inserts the second layer 3 under ground floor 2 (being the anode-side layer under the installment state), and under installment state, this second layer is the cathode side layer.Two layers are all made by foil, are particularly made by the sheet metal of steel.The first protruding 2a of ground floor 2 is inserted into the first recess 3a of the second layer 3.Described recess 3a and protruding 2a arrange according to they form embedded connection in being parallel to the plane E1 of plane E mode, this means that all can not carry out translation on any direction on this plane moves.Plane E is defined as bipolar plates and corresponding according to the plane x-y of Fig. 2 plane.

These situations do not have further to emphasize by the double-head arrow of quadrature in the reduced representation of region D 1 in hole in Fig. 3 c.Therefrom can obviously find out, in plane E and E1, not have mobile respectively.First projection and the first recess 3a are therefore about arranging in self-centering mode each other.

As finding out from Fig. 3 b, the first protruding 2a and the first recess 3a have circular port 2ax and 3ax respectively.The diameter of this hole 3ax of the first recess 3a is less than the diameter of the hole 2ax of the first protruding 2a.The corresponding area in hole also is suitable for identical ratio.

Fixture is from presenting actual accommodation section 6c in the zone of centering bolt, this accommodation section 6c makes progress through rounding 6b towards plane E.Here, the accommodation section presents cylindrical shape.

Find out as in the detailed view according to part F1 shown in Fig. 3 b among Fig. 3 d, knowing, in the angle [alpha] 2 of the cone between the shell body surface of vertical curve and protruding 2a angle [alpha] 3 less than the cone between the inner housing surface of this vertical curve and recess 3a.Here, vertical curve is corresponding to the direction of the main shaft of centering bolt 6a.This only allows the shell body surface of the first protruding 2a and the circumferential contact of the linearity on the inner housing surface of the first recess 3a, and this causes the embedded connection among the E1 of plane.

It can also be seen that the height h2 of the first protruding 2a is less than the height/depth h3 of recess 3a.This causes not resting on the second layer 3 at ground floor 2 in the zone of centering bolt 6a, and two

layers

2 and 3 only are in contact with one another in the contact area corresponding to the circumferential contact line.

Fig. 3 e also is illustrated in the zone around the second centering bolt 6d of fixture 6 sectional view according to C-C.This sectional view is replenished by the cross section D-D among Fig. 3 f, this cross section D-D and cross section C-C quadrature.Can see layer 2 the second protruding 2b, this second protruding 2b is circular and presents opening 2bx circular, that be positioned at the center, this opening 2bx be arranged to accommodation section 6f in the shell body of the second centering bolt 6d coaxial.The second recess 3b in this second protruding 2b engagement layer 3, layer 3 is disposed in ground floor 2 belows.Shown in Fig. 3 b, the cross section of the opening 3bx of the second recess 3b (at least in this sectional view) is slightly less than the cross section of the respective openings of the second protruding 2b.Yet the second recess 3b has elliptical shape, and this causes second projection among Fig. 3 e to move from left to right in limited range, this means not have embedded connection.In contrast, in the cross section D-D shown in Fig. 3 f, between protruding 2b and recess 3b, the contact site 30b in the E2 of plane, the contact of 31b place.This points out emphatically in the simplification sketch of the region D shown in Fig. 3 g 2, hole not shown in this Figure.At this, vertical double-head arrow points out that the second protruding 2b can not move along the y direction in the second recess 3b.On the contrary, horizontal double-headed is pointed out to move on the x direction and is used to compensate purpose.

Hereinafter be used to point out typical size of the present invention.The extension of recess/projection on x or y direction is usually between the 2mm to 25mm, preferably between 4mm to 15mm.Corresponding to 0.5mm to 1mm roughly, the diameter of the accommodation section 6f in the fixture 6 is preferably in the scope of 2mm to 30mm in the degree of depth of the accommodation section 6f of centering around the bolt.Opening (for example opening 2bx or 3bx) with respect to centering bolt the space usually between the 0.1mm to 3mm, preferably between 0.1mm to 1mm.

Like this, Fig. 3 a to Fig. 3 g illustrates bipolar plates 1, this bipolar plates 1 comprises at least two

layers

2,3, described at least two layers 2, each of 3 presents first recess/projection and second recess/projection, wherein, at layer 2, under 3 the complete positioning states, first recess of first recess of the ground floor 2/protruding 2a and the second layer 3/protruding 3a is locked to each other and contacts with embedded mode in the E1 of plane, yet second recess/projection of second recess of the ground floor 2/protruding 2b and the second layer 3 is at layer 2, be locked to each other under 3 the complete positioning states but only at least two

position

30b, 31b is in contact with one another,

contact site

30b, 31b is placed in can be along the virtual line 5b both sides that the principal direction of the recess/protruding 3b of the second layer 3 is extended, and, wherein in the E2 of plane, do not set up embedded connection the between recess/protruding 2b and the recess/protruding 3b.

But Fig. 4 a to Fig. 4 c illustrates the embodiment according to the alternative of bipolar plates of the present invention.Except the difference of mentioning hereinafter, being described in this and also being suitable for above.

Fig. 4 a illustrates the vertical view of bipolar plates 1 ', and its middle level 3 ' is arranged to the upper strata.The track of cross section E-E is shown on the plate that the positioning module splenium only is shown with vertical view in Fig. 4 c.At sectional view E-E shown in Fig. 4 b self.Fig. 4 b illustrate projection how with recess interlocking, just protruding 2a ' and recess 3a ', protruding 2b ' and recess 3b ', protruding 2c ' and recess 3c ' interlocking.Therefore, have three contact area 23a ', 23b ' and 23c ', each all has the recess/projection shown in a pair of Fig. 3 of being similar to e to Fig. 3 g.Recess/the projection of this expression contact area (for example contact area 23b ' among the E3 of plane) is in contact with one another with two parts respectively, and these contacts site 30b ' and 31b ' are provided with relative to one another in the both sides of virtual line 5b.This is suitable for too for the contact area 23c ' that has contact site 30c ' and 31c ' and virtual line 5c among contact area 23a ' that has contact site 30a ' and 31a ' and virtual line 5a among the E2 of plane and the plane E4.Plane E2, E3, E4 are parallel to the plane that plane E extends, yet these planes are not shown in figures.The virtual line 5a that locates at contact area 23a ' that illustrates in this example and extend substantially parallel at the virtual line 5b that contact area 23b ' locates, therefore allow on this direction, to carry out limited adjustment, that is to say, therefore the principal direction that is parallel to channel structure 4 is also at weld seam 11 " direction on.Virtual line 5c and preceding two virtual line 5a and 5b extend substantially orthogonally, and are arranged in the centre of contact area 23a ' and 23b ' basically.Virtual line 5c points out the adjustment direction located at contact site 23c '.

Therefore, Fig. 4 a to Fig. 4 c illustrates and comprises at least two layers 2 ', 3 ' bipolar plates 1 ', described at least two layers 2 ', 3 ' each comprise first, second and the 3rd recess/projection.First recess/the projection of ground floor and the first recess/protruding interlocking of the second layer, the second recess/projection of ground floor and the second recess/protruding interlocking of the second layer, and the 3rd recess/protruding interlocking of the 3rd recess/projection of ground floor and the second layer.The layer that this obtains only partly contacting with each other in plane E2, E3 and E4, just contact with each other with at least two position 30a ', 31a ', 30b ', 31b ', 30c ' and 31c ', these contacts site 30a ', 31a ', 30b ', 31b ', 30c ' and 31c ' are so that they place the mode of the offside of virtual line 5a, 5b and 5c to arrange respectively, and described virtual line extends on the principal direction of recess/protruding 3a ', 3b ' and 3c ' respectively.In plane E2, E3 and E4, between the recess/protruding 2a ' of correspondence and 3a ', 2b ' and 3b ' and 2c ' and 3c ', do not set up embedded connection respectively.Virtual line 5a and 5b extend with the angle each other in-10 ° to 10 °, and virtual line 5c becomes 80 ° to 100 ° angle to extend with virtual line 5a with 5b.

May the designing of recess/protruding 2a, 3a, 2b, 3b, 2a ', 3a ', 2b ', 3b ', 2c ' and 3c ' of the interlocking of the ground floor and the

second layer

2,3 is shown respectively based on eight kinds of different examples in Fig. 5.Example in Fig. 5 a to Fig. 5 d is illustrated in the example that forms embedded connection in its each contact plane between recess/projection, and the example shown in Fig. 5 e to Fig. 5 h does not form embedded connection between the recess/projection of interlocking.In order to make drawings clear, omitted the hole that the bolt or be used to of may being used to feel relieved is controlled the correct assembling of described layer.Fig. 5 a illustrates the how interlocking of recess/projection of two circles.Circular recess/protruding 2a, 3b contacts with each other on periphery, as as shown in Fig. 3 b and Fig. 3 c.

Fig. 5 b illustrates triangular notches/protruding 2a, this triangular notches/protruding 2a and circular recess/protruding 3a interlocking, and contact with circular recess/protruding 3a with leg-of-mutton angle.These three contact points are enough to provide embedded connection between recess/protruding 2a and 3a.Polygonal a large amount of contact angle also causes embedded connection, shown on the example of Fig. 5 c.Wherein, square notch/projection and circular recess/protruding interlocking, and in contact plane, contact circular recess/projection with its four angles.For preventing that instrument from unnecessarily wearing and tearing, it is preferred that the polygon with fillet is compared with the polygon with sharp corners.

Fig. 5 d illustrates oval recess/protruding 2a can also cause just cooperating (if size is suitable) with circular recess/protruding interlocking.On the contrary, circular recess/projection only can cause the part of the recess/projection of interlocking to contact with the interlocking of oval recess/projection, but does not cause just cooperating, shown in following Fig. 5 e and as shown in Fig. 3 e to Fig. 3 g.

Have the recess/protruding 2b of equilateral polygon shape (for example square) and the interlocking meeting of oval recess/protruding 3b and form contact site, shown in Fig. 5 f, perhaps form contact site (being not shown on this) in side edge at the place, angle.Therefore, adopt which kind of situation to depend on the relative bearing of recess/projection.Also possible two oval recess/protruding 2b, 3b are bonded with each other and (if its corresponding width is suitable) contacts with each other along its side.In this case, whether set up embedded connection and depend on selection each length of recess/projection.As long as the outer extension of engagement recess/projection does not then cause embedded connection less than the interior extension of holding recess/projection.

In addition, Fig. 5 h illustrates, when realizing engaging under the situation that is not having embedded connection, the contact of the recess/projection of interlocking is not necessarily limited to place two parts of virtual line 5b both sides, but the contact site or the contact point of varying number can be arranged, particularly in the both sides of virtual line 5b even have different quantity.

Fig. 6 illustrates an embodiment according to bipolar plates 1 of the present invention, and wherein, the positioning module splenium of two layers is so that its protrusion exceeds the mode of the both sides of board plane E forms.For example, in the upper strata, form protruding 3a with height h3x ^*, this projection 3a ^*(this illustrates circular positioning module splenium) has diameter d 3.At this circular protrusions 3a ^*In, being furnished with circular recess 3a+, this circular recess 3a+ has height h3i, and this height h3i is greater than height h3x, and this expression recess 3a+ reduces with respect to board plane E.Except protruding 2a ^*Diameter d 2 outside, layer 2 positioning module splenium designs in a similar fashion, this diameter d 2 is less than protruding 3a ^*Diameter d 3, make to go up protruding 2a ^*, 3a ^*Only cause the optimization of the height ratio in the layer respectively, but for actual location or not contribution of embedded connection.The total height he that Fig. 6 also illustrates two positioning module spleniums in the layer corresponds essentially to the total height hf of channel design 4, make the positioning module splenium not damage the sealing in the zone of the external margin of bipolar plates, but this edge is not shown at this.

In the embodiment shown in fig. 7, bipolar plates 1 illustrates three layers 2,100 and 3.Intermediate layer 100 in the zone of

contact area

23a and 23b presents recess respectively, and it extends enough big, penetrates into respectively among recess 2a and the 2b to allow

recess

3a and 3b respectively.The location of two

skins

2,3 is to realize about the described mode of two-layer embodiment in the preamble that still the 3rd layer is maintained between them.No matter the through hole shown in whether

recess

2a, 2b, 3a, 3b have, such solution all are possible.

Fig. 8 is illustrated in the interior example of using laser beam 12 ground floor 2 to be soldered to the second layer 3 in zone of channel design 4.Layer 2 and layer 3 all comprise the channel design with the part that is welded to one another, and described part for example is a narrow part that lies on another in the middle of Fig. 8.As the example of yardstick, the width of the flat of ground floor 2 is designated herein as 200 μ m, and the width of the contact-making surface of layer 3 is 170 μ m.The width of the laser beam 12 in this zone is about 50 μ m.The present invention proposes, contact area has the overlap-add region of width at least 100 μ m, this causes and engages binding (being welded to connect) in the contact area that is firmly placed between ground floor 2 and the second layer 3, even also be like this under the coarse a little situation of the route of laser beam.

For this reason, by using the accommodation section of positioning module splenium described herein and previously described fixture 6, use corresponding centering

bolt

6a and 6d that

layer

2 and 3 is arranged in stacked mode shown in Fig. 3 a to Fig. 3 g respectively, and described layer is welded to each other.

Description to the example in the preamble should only be interpreted as it is exemplary.Should emphasize that the combination of all embodiment shown here is all in framework of the present invention, and the theme of dependent claims (so long as not clearly being foreclosed) can be with any sequential combination.

Claims

1. method that is used to make bipolar plates (1), wherein, in every layer of at least two layers (2,3), form at least the first recess/projection and second recess/projection (2a, 2b, 3a, 3b), and described layer (2,3) locate in stacked mode, it is characterized in that:

First recess/projection (2a) of described ground floor (2) and first recess/projection (3a) of the described second layer (3) are engaged with each other under the complete positioning states of described two layers (2,3), and contact with each other with embedded mode in the E1 of plane, and,

Second recess/projection (2b) of described ground floor (2) and second recess/projection (3b) of the described second layer (3) are engaged with each other under the complete positioning states of described two layers (2,3), and in the E2 of plane, only partly at least two positions (30b, 31b), contact with each other

Wherein, described contact site (30b, 31b) is placed in the both sides of the virtual line (5b) that can extend along the principal direction of second recess/projection (3b) of the described second layer (3), and, wherein between described second recess/projection (2b, 3b), do not set up embedded connection, and, wherein said two layers (2,3) are bonded to each other by means of bonding, and the recess/projection of at least one layer is nested in the projection/recess (6c, 6f) of the complementation of positioner (6).

2. method that is used to make bipolar plates (1), wherein, in each of at least two layers (2 ', 3 '), form at least first, second and the 3rd recess/projection (2a ', 2b ', 2c ', 3a ', 3b ', 3c '), and described layer (2 ', 3 ') is located in stacked mode, it is characterized in that:

First recess/projection of the first recess/projection of described ground floor (2 ') (2a ') and the described second layer (3 ') (3a '), second recess/projection of the second recess/projection of described ground floor (2 ') (2b ') and the described second layer (3 ') (3b '), and the 3rd recess/projection of the 3rd recess/projection of described ground floor (2 ') (2c ') and the described second layer (3 ') (3c ') at described two layers (2 ', 3 ') be engaged with each other under the complete positioning states, and respectively at plane E2, among E3 and the E4 only partly at least two parts (30a ', 31a ', 30b ', 31b ', 30c ', 31c ') is in contact with one another in, wherein, described contact portion (30a ', 31a ', 30b ', 31b ', 30c ', 31c ') be placed in can along the respective notches/projection of the described second layer (3 ') (3a ', 3b ', 3c ') virtual line (5a that principal direction is extended, 5b, both sides 5c), and, wherein corresponding recess/projection (2a '/3a ', 2b '/3b ', 2c '/3c ') do not set up embedded connection between

Wherein, described first straight line and second straight line (5a, 5b) are in-10 ° to 10 ° angle extension, and wherein said the 3rd straight line (5c) becomes 80 ° to 100 ° angle to extend with described first straight line with second straight line (5a, 5b),

Wherein, described at least two layers (2,3) mutually combine by bonding, and the recess/projection of at least one layer is nested in the projection/recess (6c, 6f) of the complementation of positioner (6).

3. method according to claim 1 and 2, it is characterized in that, in at least two layers (2,3,2 ', 3 '), (2a, 2a ', 2b, 2b ', 2c ', 3a, 3a ', 3b, 3b ', 3c ') forms channel design (4) in identical step with described recess/projection.

4. according to the described method of one of claim 1 to 3, it is characterized in that, at least one recess/projection (2a, 2a ', 2b, 2b ', 2c ', 3a, 3a ', 3b, 3b ', 3c ') comprises through hole (2ax, 2ax ', 2bx, 2bx ', 2cx ', 3ax, 3ax ', 3bx, 3bx ', 3cx '), and the centering bolt of described fixture (6) (6a, 6d) engages by this opening.

5. according to the described method of one of claim 1 to 4, it is characterized in that described layer (2,3) is made of metal, and preferably is made of steel.

6. according to the described method of one of claim 1 to 5, it is characterized in that described associated methods is gluing or welding, is preferably laser welding.

7. according to the described method of one of claim 1 to 6, it is characterized in that, form described recess/projection (2a, 2a ', 2b, 2b ', 2c ', 3a, 3a ', 3b, 3b ', 3c ') and/or channel design (4) by mold pressing, deep draw, hydroforming, adiabatic shaping or roll forming.

8. a bipolar plates (1), comprise at least two layers (2,3), wherein, each layer of at least two layers (2,3) comprises first recess/projection and second recess/projection (2a, 2b, 3a, 3b), wherein, first recess/projection (2a) of described ground floor (2) and first recess/projection (3a) of the described second layer (3) are engaged with each other under the complete positioning states of described two layers (2,3), and are in contact with one another with embedded mode in the E1 of plane, and

Second recess/projection (2n) of described ground floor (2) and second recess/projection (3b) of the described second layer (3) are engaged with each other under the complete positioning states of described two layers (2,3), and in the E2 of plane, only partly at least two positions (30b, 31b), be in contact with one another

Wherein, described contact site (30b, 31b) is placed in the both sides of the virtual line (5b) that can extend along the principal direction of second recess/projection (3b) of the described second layer (3), and, wherein between described second recess/projection (2b, 3b), do not set up embedded connection.

9. a bipolar plates (1), comprise at least two layers (2 ', 3 '), wherein, at least two layers (2 ', 3 ') comprise at least the first, the second and the 3rd recess/projection (2a ', 2b ', 2c ', 3a ', 3b ', 3c '), wherein, first recess/projection of the first recess/projection of described ground floor (2 ') (2a ') and the described second layer (3 ') (3a '), second recess/projection of the second recess/projection of described ground floor (2 ') (2b ') and the described second layer (3 ') (3b '), and the 3rd recess/projection of the 3rd recess/projection of described ground floor (2 ') (2c ') and the described second layer (3 ') (3c ') at described two layers (2 ', 3 ') be engaged with each other under the complete positioning states, and respectively at plane E2, among E3 and the E4 only partly at least two parts (30a ', 31a ', 30b ', 31b ', 30c ', 31c ') is in contact with one another in, wherein, described contact portion (30a ', 31a ', 30b ', 31b ', 30c ', 31c ') be placed in can along the respective notches/projection of the described second layer (3) (3a ', 3b ', 3c ') virtual line (5a that principal direction is extended, 5b, both sides 5c), at described plane E2, among E3 and the E4 corresponding recess/projection (2a '/3a ', 2b '/3b ', 3a '/3b ') there is not embedded connection between

Wherein, described first straight line and second straight line (5a, 5b) are in-10 ° to 10 ° angle extension, and wherein said the 3rd straight line (5c) becomes 80 ° to 100 ° angle to extend with described first straight line with second straight line (5a, 5b).

10. according to Claim 8 or 9 described bipolar plates, it is characterized in that the recess/projection of described ground floor (2) (2a, 2b) is self-centering for the recess/projection (3a, 3b) of the described second layer (3).

11. 9 or 10 described bipolar plates according to Claim 8,, it is characterized in that at least one in first, second recess/projection of the described ground floor and/or the second layer (2,3) and the 3rd recess/projection under suitable situation comprises through hole (2ax, 2bx, 3ax, 3bx, 2ax ', 2bx ', 2cx ', 3ax ', 3bx ', 3cx ').

12. bipolar plates according to claim 11, it is characterized in that described through hole (2ax, 2bx, 3ax, 3bx, 2ax ', 2bx ', 2cx ', 3ax ', 3bx ', 3cx ') is arranged to be positioned at the center of corresponding recess/projection (2a, 2b, 3a, 3b, 2a ', 2b ', 2c ', 3a ', 3b ', 3c ').

13. to one of 12 described bipolar plates, it is characterized in that according to Claim 8 each has the first recess/projection (2a, 3a) of the described ground floor and the second layer (2,3) round-shaped or have the polygonal shape that has fillet.

14. according to Claim 8 with 10 to 13 in each described bipolar plates, it is characterized in that, second recess/projection (2b) of described ground floor (2) be circular or have fillet polygonal, and second recess/projection (3b) of the described second layer (3) is oval-shaped.

15. according to claim 9, one of 11 and 12 described bipolar plates, it is characterized in that, at least described first, second and the 3rd recess/projection of described ground floor (2 ') (2a ', 2b ', 2c ') be circular or have fillet polygonal, and first, second of the described second layer (3 ') is oval-shaped with the 3rd recess/projection (3a ', 3b ', 3c ').

16. according to Claim 8 to one of 15 described bipolar plates, it is characterized in that, at least one of described at least two layers (2,3) has channel design (4), and the principal spread direction (5) of second recess/projection (3b) of the described second layer (3) is parallel to the principal direction extension of described channel design (4).

17. to one of 16 described bipolar plates, it is characterized in that the channel design (4) of described at least two layers (2,3) provides the chamber between described at least two layers (2,3), especially for the chamber of conduct coolant medium according to Claim 8.

18. to one of 17 described bipolar plates, it is characterized in that described recess/projection (2a, 3a) has conical in shape according to Claim 8.

19. bipolar plates according to claim 18 is characterized in that, the cone angle of the recess/projection of described ground floor (2) (α 2) is greater than or less than the cone angle (α 3) of recess/projection of the complementation of the second layer (3).

20. to one of 19 described bipolar plates, it is characterized in that the described recess/projection (2a or 3a) of a layer (2 or 3) is more shallow than the described recess/projection (3a or 2a) of another layer (3 or 2) according to Claim 8.

21. according to Claim 8 to one of 20 described bipolar plates, it is characterized in that, each is made of described recess/projection (2a, 2a ', 2b, 2b ', 2c ', 3a, 3a ', 3b, 3b ', 3c ') first recess/projection of pointing to the first direction vertical with board plane E and second recess/projection of being disposed in the interior directed in opposite directions of first recess/projection, wherein, described second recess/projection is compared described first recess/projection and is had the bigger degree of depth.