Flux field plates, bipolar plates and their manufacturing process

Abstract

The present application provides a method for manufacturing a flow field plate for a fuel cell unit. This method comprises the following: forming on the first side of a metal plate a first flow field for circulating a reaction fluid, wherein the reaction zone of the first flow field has first ribs bounding first flow channels. The formation of the first flow field comprises the following steps: cutting out first patterns corresponding to said first ribs from first electrically conductive adhesive films; and adhering said first patterns to the first side of the metal plate such that, measured from the top, at least 10% of the height of the first ribs is formed by the first patterns.The present application further provides a method for manufacturing a bipolar plate for a fuel cell, as well as flow field plates and bipolar plates manufactured using the aforementioned method. According to this application, the contact conductivity of flow field plates can be improved, and flow field plates can be manufactured easily, thereby reducing the manufacturing costs of the flow field plates.

Description

FIELD OF THE INVENTION

[0001] The present application relates generally to fuel cell technology, in particular it relates to flow field plates and bipolar plates for fuel cells and their manufacturing process. STATE OF THE ART

[0002] Fuel cells, which generate electricity based on electrochemical reactions between a fuel and an oxidizer, are increasingly being used for power generation, particularly in electric vehicles. One widely used fuel cell is the proton exchange membrane fuel cell, which uses hydrogen as the fuel and oxygen as the oxidizer. Typically, a membrane electrode assembly (MEA) is placed between two flow-field plates to form the fuel cell assembly. The two flow-field plates serve as the cathode plate and the anode plate and contain flow fields for supplying the reactant fluids (namely, hydrogen, oxygen, or air) to the MEA.

[0003] Due to its excellent thermal conductivity, electrical conductivity, and compactness, metal is typically used to manufacture flow-field plates. However, the chemical properties of the metal materials commonly used for flow-field plates (stainless steel, titanium, etc.) are unstable in the operating environment of proton exchange membrane fuel cells (e.g., low pH, high humidity, operating temperature of approximately 80 °C), resulting in problems with corrosion resistance and contact conductivity for metal flow-field plates.

[0004] In the current state-of-the-art flow-field plate manufacturing technology, a carbon-based coating is often applied to metal flow-field plates to improve their corrosion resistance and contact conductivity. However, the application of a carbon-based coating must be performed in a vacuum environment, which is a complicated, time-consuming, and costly process that is not suitable for mass production of flow-field plates. Furthermore, to maintain a substantially constant contact resistance between flow-field plates with a carbon-based coating and the MEA, a relatively large holding force is required between the flow-field plates and the MEA. This force depends on the cell stack clamping device of the fuel cells.However, due to the vibrations in the working environment of fuel cells, the clamping device may potentially loosen and detach, resulting in a reduction in the holding force, thereby increasing the contact resistance between the flow field plates and the MEA.

[0005] Consequently, it is necessary to improve the current technology for manufacturing flow field plates. DISCLOSURE OF THE INVENTION

[0006] The object of the present application is to provide an improved method for manufacturing a flow field plate for a fuel cell assembly to overcome at least one of the foregoing deficiencies.

[0007] According to one aspect of this application, a method for manufacturing a flow field plate for a fuel cell unit is provided. The method comprises the following: forming, on the first side of a metal plate, a first flow field for circulating a reaction fluid, wherein the reaction zone of the first flow field has first webs delimiting first flow channels. Forming the first flow field comprises the following steps: cutting out first patterns from first electrically conductive adhesive films corresponding to said first webs; and gluing said cut-out first patterns on the first side to the metal plate so that at least 10% of the height of the first webs, measured from the upper end, is formed by the first patterns.

[0008] According to a further aspect of this application, a method for manufacturing a bipolar plate for a fuel cell is provided, comprising: using a cathode plate manufactured according to the aforementioned method; using an anode plate manufactured according to the aforementioned method; and connecting the cathode plate and the anode plate in such a way that the first flow fields are back-to-back to each other, thus forming a bipolar plate.

[0009] According to yet another aspect of this application, a flow field plate for a fuel cell unit is provided, comprising: a metal plate; a first flow field formed on the first side of the metal plate and serving to circulate a reaction fluid, wherein the reaction zone of the first flow field has first webs delimiting first flow channels; and first electrically conductive adhesive films, wherein the first electrically conductive adhesive films take the form of first patterns corresponding to the first webs and are adhered to the metal plate on the first side so that at least 10% of the height of the first webs, measured from the upper end, is formed by the first patterns.

[0010] According to yet another aspect of this application, a bipolar plate for a fuel cell is provided, comprising: an anode plate, wherein the anode plate is a aforementioned flow field plate; a cathode plate, wherein the cathode plate is another aforementioned flow field plate; wherein the anode plate and the cathode plate are connected to one another in such a way that the first flow fields are rear-side to one another.

[0011] According to this application, the contact conductivity of flow field plates can be improved and flow field plates can be easily manufactured, thereby reducing the manufacturing cost of the flow field plates. DESCRIPTION OF THE CHARACTERS

[0012] The above and other aspects of the present application will be better understood and familiarized with in conjunction with the figures below. It should be noted that the figures are merely schematic and not drawn to scale. In the figures: Fig. 1 schematically shows two cell units of the cell stack of an exemplary fuel cell, for which cell units flow field plates manufactured according to the method of a preferred embodiment of this application were used; Fig. 2 is a plan view of a flow field plate according to a preferred embodiment of this application, schematically showing the first side of the flow field plate; Fig. 3 is a bottom view of the flow field plate from Fig. 2, which schematically shows the second side of the flow field plate opposite the first side; Fig. Figure 4 is a schematic cross-sectional view of line II of Fig. 1, which schematically shows the cross-sectional area of ​​a variant of the flow field plate according to this application; Fig. 5 is one with Fig. 2 comparable schematic cross-sectional view schematically showing the cross-sectional area of ​​another variant of the flow field plate according to this application; Fig. 6 schematically shows a plan view of the layer structure with a first electrically conductive adhesive film applied between two layers of backing film according to a preferred embodiment of this application; Fig. 7 shows a side view of the layer structure of Fig. 6; Fig. 8 is a plan view of the layer structure of Fig. 6, which schematically shows a first image cut out of the layer structure. Fig. 9 is one with Fig. 2 comparable top view, wherein the first electrically conductive adhesive film and the second adhesive film have not yet been glued to the metal plate of the flow field plate; Fig. 10 is one with Fig. 2 and Fig. 9 comparable top view, wherein the first electrically conductive adhesive film has been glued to the metal plate of the flow field plate, while the second adhesive film has not yet been glued to the metal plate of the flow field plate; Fig. 11 is an enlarged view of the dashed line area A of Fig. 10, which schematically shows a flow channel structure that can be formed using the manufacturing method according to this application; and Fig. Figure 12 is an enlarged view of the dashed line area B of Fig. 10, which schematically shows another flow channel structure that can be formed using the manufacturing method according to this application. List of reference symbols 1 cell unit 3 Proton exchange membrane 5 Cathode diffusion layer 7 Cathode catalyst layer structure 9 Anode diffusion layer 11 Anode catalyst layer structure 100 flow field plate 101 Metal plate 101a first page 101b second page 101c Entrance 101d Exit 101e Entrance 101f Exit 101g first opening 101h second opening 103 first flow field 105 Entrance distribution zone 107 Reaction zone 107a1 side wall 107a2 floor wall 107a first flow channel 107b first bridge 107b1 upper end 107b2 lower end 108 protruding element 109 Exit assembly zone 111 first electrically conductive adhesive film 113a second flow channel 113b second bridge 113b1 upper end 115 second flow field 117a third flow channel 117b third bridge 117b1 upper end 118 third electrically conductive adhesive film 200 backing sheets 300 layer structure DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] In the following, some preferred embodiments of the present application are described in detail by way of examples. Those skilled in the art should understand that these embodiments are merely exemplary and do not constitute a limitation of the present application. Furthermore, the features of the embodiments of the present application can be combined with one another where there are no conflicts. For the sake of simplicity, other components have been omitted from the figures, but this does not mean that the flow field plates, bipolar plates, fuel cell units, and fuel cells of the present application do not include other patterns and components. It should be understood that the dimensions and scale relationships of the individual patterns and components, as well as the number of components, in the figures do not constitute a limitation of the present application.

[0014] Fuel cells can be used in vehicles to provide electricity, where they drive the vehicle's electric motor, provide motive power, or cause the on-board system to perform various functions. Fig. 1 schematically shows two cell units 1 of the cell stack of an exemplary fuel cell.

[0015] The exemplary fuel cell is a proton exchange membrane fuel cell (PEMFC), and its cell stack was formed by stacking a plurality of cell units 1. As described in detail below, the flow field plate 100 manufactured according to the method of a preferred embodiment of this application can be used for the cell units 1 to serve as a cathode plate and / or anode plate. For example, in a cell unit 1, one flow field plate 100 can serve as the cathode plate and another flow field plate 100 can serve as the anode plate. Alternatively, the flow field plate 100 can be combined with other flow field plates.

[0016] As in Fig. 1, each cell unit 1 usually consists of a cathode plate (in Fig. 1 the left flow field plate 100 of each cell unit 1), an anode plate (in Fig. 1, the right flow field plate 100 of each cell unit 1), a proton exchange membrane 3, a cathode diffusion layer 5 and cathode catalyst layer structure 7 located between the cathode plate and the proton exchange membrane 3, and an anode diffusion layer 9 and anode catalyst layer structure 11 located between the anode plate and the proton exchange membrane 3. The cathode diffusion layer 5, the cathode catalyst layer structure 7, the anode diffusion layer 9, the anode catalyst layer structure 11, and the proton exchange membrane 3 are generally manufactured from a single piece and are referred to as a membrane-electrode assembly (MEA). The cathode diffusion layer 5 and the anode diffusion layer 9 serve as supports for the cathode catalyst layer structure 7 and the anode catalyst layer structure 11, respectively, and transport the reaction fluid and the reaction products (hydrogen, oxygen / air, water, etc.).As in . Fig. 4 and Fig. As shown schematically in Figure 5, a cathode flow field and an anode flow field are formed on the cathode plate and the anode plate, respectively. The cathode flow fields of the cathode plates of multiple cell units 1 can form a cathode flow channel of the cell stack (not shown), and the anode flow fields of the anode plates of multiple cell units 1 can form an anode flow channel of the cell stack (also not shown).

[0017] The electrochemical reactions of a PEMFC take place in the MEA and essentially involve hydrogen oxidation (HOR) and oxygen reduction (ORR). H2 and O2 are transported via the anode diffusion layer 9 and the cathode diffusion layer 5, respectively, into the anode catalyst layer structure 11 and the cathode catalyst layer structure 7, with the H2 in the anode catalyst layer structure 11 releasing its electrons under the influence of the anode catalyst, thus forming H + is created. The H +is conducted to the cathode side via the proton exchange membrane 3 and reacts with O2 in the cathode catalyst layer structure 7 under the influence of the cathode catalyst to form H2O. The H2O is transported via the cathode diffusion layer 5 and the anode diffusion layer 9 into the cathode flow field and the anode flow field and then discharged from the PEMFC via the cathode flow channel and the anode flow channel. The electrons flow to the cathode via an external circuit (not shown), creating a current flow.

[0018] Fig. 2 to Fig. 4 schematically show a flow field plate 100 manufactured using a manufacturing method according to a preferred embodiment of this application. As in Fig. 2 and Fig. As can be seen in Figure 3, the flow field plate 100 comprises a metal plate 101 having a first side 101a and a second side 101b opposite the first side. The metal plate 101 can be made of an iron alloy (stainless steel), light metal and its alloy (essentially titanium and its alloy, and aluminum and its alloy). The metal plate 101 includes an inlet 101c configured to receive the reaction fluid (in the case of PEMFCs, these are reaction gases, specifically hydrogen, oxygen, or air) and an outlet 101d configured to discharge reaction products. The inlet 101c and the outlet 101d are openings extending through the metal plate 101.

[0019] As in Fig. 2 and Fig. As can be seen in Figure 4, the flow field plate 100 further comprises a first flow field 103 formed on the first side 101a of the metal plate 101 and used to circulate a reaction fluid. The first flow field 103 comprises an inlet distribution zone 105, a reaction zone 107, and an outlet collection zone 109, which are arranged successively in the flow direction of the reaction gas. The reaction zone 107 has first webs 107b delimiting first flow channels 107a. The first flow channels 107a extend between the inlet distribution zone 105 and the outlet collection zone 109. The inlet distribution zone 105 of the first flow field 103 is arranged to be close to the inlet 101c of the metal plate 101 and is connected to the inlet 101c to receive the reaction gas from the inlet 101c, and is configured to distribute the reaction gas to the individual flow channels 107a.The exit collection zone 109 is configured to collect the reaction products from the first flow channels 107a and is arranged to be close to the exit 101d of the metal plate 101 and to be connected to the exit 101d to discharge the reaction products to the exit 101d.

[0020] Further with reference to Fig. 2 and Fig. 4, the flow field plate 100 further comprises first electrically conductive adhesive films 111, wherein the first electrically conductive adhesive films 111 take the form of first patterns corresponding to the first webs 107b and are glued to the metal plate 101 on the first side 101a so that from the upper end 107b1 ( Fig. 4) at least 10% (for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or any value therebetween) of the height of the first webs 107b are formed by the first patterns. As in Fig. 4, when the flow field plate 100 serves as an anode plate or a cathode plate and is assembled with the MEA, the first electrically conductive adhesive film 111 can adhere the metal plate 101 to the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9 of the MEA.

[0021] As specifically described below in connection with the method for manufacturing the flow field plate 100, the inventors have recognized that the aforementioned configuration of the flow field plate 100 according to this application can offer numerous advantages: (1) The first electrically conductive adhesive film 111 can maintain a stable adhesive force between the metal plate 101 and the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9 during long-term operation of the fuel cell to keep the contact resistance substantially constant, which serves to improve the contact conductivity of the flow field plate 100 and consequently increases the reliability and power generation performance of the fuel cell;(2) Placing the first electrically conductive adhesive film 111 can reduce the need to apply additional holding force between the metal plate 101 and the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9, thus increasing the reliability of the fuel cell; (3) The first electrically conductive adhesive film 111 covers a portion of the metal plate 101, which helps prevent corrosion from occurring on that portion of the metal plate 101 and thus prolongs the service life of the flow field plate 100; (4) By firmly adhering the first electrically conductive adhesive film 111 to the metal plate 101, the metal plate 101 is eliminated from the complicated and time-consuming process of surface modification, thereby making the flow field plate 100 easy to manufacture and reducing manufacturing costs, which is beneficial for the mass production of flow field plates 100.(5) At least 10% of the height of the first webs 107b, measured from the upper end 107b1, is formed by the first patterns, so that the first electrically conductive adhesive film 111 forms at least part of the flow field of the reaction zone 107, which contributes to reducing or even completely eliminating the required punching work in the manufacture of the reaction zone 107 of the flow field plate 100 and increases the flexibility with regard to design and manufacture of the flow field plate 100.;

[0022] In the following, with reference to Fig. 4 to Fig. 10, an exemplary method for manufacturing the flow field plate 100 according to this application is specifically described. Fig. Figure 9 is a plan view of the metal plate 101, schematically showing the first side 101a of the metal plate 101. The metal plate 101 already has an inlet 101c and an outlet 101d. The inlet 101c and the outlet 101d of the metal plate 101 can be formed using any method already known in the art, such as machining, stamping, etc.

[0023] The method for producing the flow field plate 100 according to this application comprises forming a first flow field 103 on the first side 101a of the metal plate 101, said first flow field serving to circulate a reaction fluid. As previously explained, the reaction zone 107 of the first flow field 103 has first webs 107b defining first flow channels 107a. The formation of the first flow field 103 comprises the following steps: (1) Cutting out first patterns from first electrically conductive adhesive films 111 ( Fig. 8); and (2) gluing the cut-out first patterns on the first side 101a to the metal plate 101 so that at least 10% of the height of the first webs 107b, measured from the upper end, is formed by the first patterns ( Fig. 10). It should be understood that the manufacturing method according to the present application can offer the above advantages (1) to (5).

[0024] The manufacturing method according to the present application increases the flexibility regarding the design and manufacture of the flow field plate 100. For example, Fig. 11 and Fig. 12 shows two flow channel structures that can be formed using the manufacturing method according to this application. Fig. Figure 11 shows a first flow channel 107a with a tapered structure. The first flow channel 107a is defined by the shape of the first webs 107b. Specifically, the first flow channel 107a initially has a narrowing and then a widening of the flow area in the flow direction of the reaction fluid (as shown in the figure by the dashed arrow), so that the flow of the reaction fluid or the reaction products is accelerated. In this text, "flow area," unless otherwise stated, means the effective cross-sectional area of ​​a channel of a component or part through which a fluid flows. This tapered structure can be provided at a desired position in the first flow field 103 to achieve the effect of accelerating the reaction fluid or the reaction products.For example, such a tapered structure can be provided at a position downstream of the reaction zone of the cathode flow field to accelerate the discharge of the reaction products. Fig. 12 shows a first flow channel 107a with a structure that induces turbulent flow. Specifically, projecting elements 108 extending into the first flow channels 107a can be attached to the side walls (i.e., the first webs 107b) of the first flow channels 107a to induce turbulent flow of the reaction fluid. This promotes an enhanced reaction in the reaction zone 107.

[0025] Flow channel structures such as those in Fig. 11 and Fig. 12 are difficult to form using conventional methods such as punching and machining. However, using the manufacturing method according to the present application, first flow channels 107a with a tapered structure and a structure that induces turbulent flow can be easily and inexpensively formed. It should be understood that other flow channel structures that are difficult to form using conventional methods such as punching and machining can also be easily and inexpensively formed using the manufacturing method according to this application, and this application does not impose any limitations in this regard.

[0026] Furthermore, by using the manufacturing method according to this application, in contrast to conventional methods such as punching and machining, any kind of complicated flow field patterns can be easily and inexpensively formed, and the costs for designing and manufacturing punching tools can be reduced or even eliminated entirely.

[0027] Importantly, the manufacturing method according to the present application can increase the flexibility regarding the design and manufacture of the flow field plate 100.

[0028] In some embodiments, the entire (100%) height of the first webs 107b measured from the upper end 107b1 may be formed by the first electrically conductive adhesive films 111 (i.e., the first patterns). As shown in Fig. 5 and Fig. 9, the first zone of the metal plate 101 corresponding to the reaction zone 107 is substantially planar. As used herein, "substantially planar" means within manufacturing tolerances. In this case, the first patterns may be arranged such that the entire height of the first lands 107b measured from the upper end 107b1 is formed by the first patterns. Accordingly, the step of bonding the cut-out first patterns on the first side 101a to the metal plate 101 comprises bonding the cut-out first patterns on the first side 101a to the first zone of the metal plate 101 to form the entire first lands 107b. By this method, the flexibility regarding the design and manufacturing of the flow field plate 100 can be further increased. For example, see the structures of the flow field plate 100 (this flow field plate 100 serves as a cathode plate) below in Fig. 5, where the entire height of the first ridges 107b measured from the upper end 107b1 is formed by the first electrically conductive adhesive films 111 (i.e., the first patterns). In this case, the side walls 107a1 of the first flow channels 107a may be perpendicular to the bottom walls 107a2 of the first flow channels 107a, i.e., the draft angle is 0. Such a flow channel structure contributes to increasing the flow channel density of the reaction zone 107 and consequently improves the performance of the flow field plate 100. Such a flow channel structure is difficult to form using conventional methods such as punching and machining. However, using the manufacturing method according to the present application, first flow channels 107a in which the side walls 107a1 are perpendicular to the bottom wall 107a2 of the first flow channel 107a can be easily and inexpensively formed.

[0029] In some other embodiments, as in Fig. 4 and Fig. 5, measured from the upper end 107b1 to the lower end 107b2 opposite, a part of the height of the first webs 107b can be formed by punching the metal plate 101. Specifically, please see the flow field plate 100 (this flow field plate 100 serves as an anode plate) above in Fig. 5, the first webs 107b consist of a first part and a second part. The first part is formed by punching the metal plate 101, and the second part is formed by gluing the first electrically conductive adhesive films 111 to the first part. This means that the formation of the first flow field 103 further comprises the step of forming the first part of the first webs 107b by punching the metal plate 101, and that the step of gluing the cut-out first patterns on the first side 101a to the metal plate 101 comprises gluing the cut-out first patterns to these first parts to form these second parts and consequently the entire first webs 107b.

[0030] The first electrically conductive adhesive films 111 comprise a first adhesive material and first electrically conductive particles distributed on the first adhesive material. The first electrically conductive particles can be distributed on the first adhesive material using any suitable method in any suitable weight percentage. This depends specifically on the conductive properties of the first adhesive material itself as well as on the density and conductivity of the first electrically conductive particles. The first adhesive material can preferably be polymethyl methacrylate (PMMA), acrylic adhesive, polypyrrole, epoxy resin, silicone resin, polyamide, polyimide, or fluororubber. The first electrically conductive particles can preferably be gold (Au), graphite, a carbon material with a high specific surface area such as Ketjen black, carbon black, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, chromium nitride (CrN), or titanium nitride (TiN).It should be understood that this application is not limited thereto, and any suitable materials can be used for the first adhesive material and the first electrically conductive particles that ensure that the first electrically conductive adhesive films 111 can maintain a stable adhesive force and a substantially constant contact resistance between the metal plate 101 and the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9.

[0031] In some embodiments, the first electrically conductive adhesive films 111 are configured to adhere the metal plate 101 to the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9 such that an adhesive force of at least 2 N / cm (e.g., 2 N / cm, 2.5 N / cm, 3 N / cm, or more) is provided between the corresponding diffusion layer and the metal plate 101. This contributes to maintaining a stable adhesive force and a substantially constant contact resistance between the metal plate 101 and the corresponding diffusion layer. Furthermore, this helps reduce the need to apply an additional holding force between the metal plate 101 and the corresponding diffusion layer.

[0032] As in Fig. 4 and Fig. As can be seen in Figure 5, each of the first flow channels 107a is defined by two side walls 107a1 and a bottom wall 107a2 extending between the two side walls 107a1. Two side walls 107a1 are formed by two adjacent first ridges 107b, and the bottom wall 107a2 is formed by the portion of the metal plate 101 located between the two adjacent first ridges 107b. The first patterns (i.e., the first electrically conductive adhesive films 111) do not cover any portion of the metal plate 101. It should be understood that the portion of the metal plate 101 located between two adjacent first ridges 107b or the entire metal plate 101 may be subjected to a surface treatment to make it corrosion-resistant.

[0033] In some embodiments, as in Fig. 6 to Fig. 8, the step of cutting out the first patterns corresponding to the first webs 107b from the first electrically conductive adhesive films 111 may comprise applying the first electrically conductive adhesive films 111 between two layers of backing film 200 to form a layer structure 300 and cutting out the first patterns corresponding to the first webs 107b from the layer structure 300. Fig. 6 schematically shows a plan view of the layer structure 300 with a first electrically conductive adhesive film 111 applied between two layers of backing film 200, Fig. 7 shows a side view of the layer structure of Fig. 6, and Fig. 8 is a plan view of the layer structure 300 of Fig. 6, which schematically shows the first patterns cut out of the layer structure 300. Subsequently, the step of adhering the cut-out first patterns on the first side 101a to the metal plate 101 comprises detaching the cut-out first patterns from the backing films 200 and adhering them on the first side 101a to the metal plate 101 (as in Fig. 10). The backing film 200 can be made of a material suitable for holding the first electrically conductive adhesive films 111 when the first patterns are cut out of the first electrically conductive adhesive films 111 and for allowing easy removal of the first electrically conductive adhesive films 111 after the first patterns have been cut out of the first electrically conductive adhesive films 111 without causing damage.

[0034] See again Fig. 2, according to which the inlet distribution zone 105 and the outlet collection zone 109 of the first flow field 103 can be formed in a manner comparable to the reaction zone 107. Specifically, at least one of the inlet distribution zone 105 and the outlet collection zone 109 comprises second webs 113b delimiting second flow channels 113a. The flow field plate 100 further comprises second adhesive films (not labeled), wherein the second adhesive films take the form of second patterns corresponding to the second webs 113b and are glued to the metal plate 101 on the first side 101a so that at least a part (for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or any value therebetween) of the height of the second webs 113b is formed by the second patterns, measured from the upper end 113b1.In other words, forming the first flow field 103 further comprises the following steps: cutting out second patterns corresponding to the second ridges 113b from second electrically conductive adhesive films; and adhering the cut-out second patterns on the first side 101a to the metal plate 101 so that at least a part of the height 113b1 of the second ridges 113b, measured from the upper end, is formed by the second patterns.

[0035] In this way, several advantages can be provided: (1) The second adhesive film can further help to maintain a stable adhesive force between the metal plate 101 and the corresponding diffusion layer of the cathode diffusion layer 5 and the anode diffusion layer 9, so as to keep the contact resistance substantially constant, which serves to improve the contact conductivity of the flow field plate 100 and consequently improves the performance of the fuel cell using the flow field plate 100;(2) Measured from the upper end 113b1, at least a portion of the height of the second webs 113b is formed by the second patterns, so that the second adhesive film forms at least a portion of the flow field of at least one of the inlet distribution zone 105 and the outlet collection zone 109, which contributes to reducing or even eliminating the required punching work in the manufacture of the inlet distribution zone 105 and the outlet collection zone 109 of the flow field plate 100, and increases the flexibility in design and manufacture of the flow field plate 100.;

[0036] Preferably, the second adhesive films may be films made of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or polyimide (PI) coated on the surface with acrylic adhesive. It should be understood that the second adhesive film is not limited to these and may be made of other suitable materials.

[0037] In some embodiments, as in Fig. 9, the second zone of the metal plate 101 corresponding to at least one of the input distribution zone 105 and the output collection zone 109 is substantially planar. It is conceivable that the second adhesive films are glued to the second zone ( Fig. 2) and arranged so that the entire height of the second ridges 113b measured from the upper end 113b1 is formed by the second patterns. In other words, the second patterns are arranged so that the entire height of the second ridges measured from the upper end 113b1 is formed by the second patterns, and the step of adhering the cut-out second patterns on the first side 101a to the metal plate 101 comprises adhering the cut-out second patterns on the first side 101a to the second zone of the metal plate 101, thereby forming the entire second ridges 113b.It should be understood that, as previously described in connection with the reaction zone 107, the method described herein makes it easy and cost-effective to form the flow channel structures and flow channel patterns of the inlet distribution zone 105 and the outlet collection zone 109, which are difficult to form using conventional methods such as stamping and machining. Furthermore, it should be understood that in other embodiments, a portion of the second lands 113b may be formed by stamping the metal plate 101, measured from the lower end opposite the upper end 107b1, and the other portion of the second lands 113b may be formed by adhering the second adhesive film to this portion. In this way, the entire second lands 113b may be formed.

[0038] Referring again to Fig. 2 and Fig. 3, the metal plate 101 further comprises an inlet 101e arranged to receive a cooling fluid and an outlet 101f arranged to discharge the cooling fluid. Furthermore, the metal plate 101 further comprises a first opening 101g and a second opening 101h arranged to connect to the reaction fluid inlet and the reaction product outlet, respectively, of another cooperating metal plate 101. The inlet 101e, the outlet 101f, the first opening 101g, and the second opening 101h are all openings extending through the metal plate 101.

[0039] As in Fig. As can be seen in Figure 3, the flow field plate 100 can further comprise a second flow field 115 formed on the second side 101b of the metal plate 101 opposite the first side 101a and serving to circulate a cooling fluid. The second flow field 115 comprises third webs 117b defining third flow channels 117a. The third flow channels 117a extend between the inlet 101e and the outlet 101f. The cooling fluid flows from the inlet 101e into the second flow field 115 and exits the second flow field 115 through the outlet 101f.

[0040] It is conceivable that the second flow field 115 is formed in a manner comparable to the reaction zone 107. Specifically, the flow field plate 100 further comprises third electrically conductive adhesive films 118 ( Fig. 4 and Fig. 5), wherein the third electrically conductive adhesive films 118 take the form of third patterns corresponding to the third webs 117b and are glued to the metal plate 101 on the second side 101b so that at least 10% (for example 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or any value therebetween) of the height of the third webs 117b is formed by the third patterns, measured from the upper end 117b1.

[0041] In other words, the method for forming the flow field plate 100 according to this application further comprises forming, on the second side 101b of the metal plate 101 opposite the first side 101a, a second flow field 115 for circulating a cooling fluid. Forming the second flow field 115 comprises the following steps: cutting out third patterns from third electrically conductive adhesive films 118 corresponding to the third webs 117b; and gluing the cut-out third patterns onto the second side 101b of the metal plate 101 so that at least 10% of the height of the third webs 117b, measured from the upper end 117b1, is formed by the third patterns.

[0042] In this way, several advantages can be provided: (1) When two flow field plates 100 are bonded together in such a manner that the first flow fields 103 are back-to-back with each other to form a bipolar plate, the third electrically conductive adhesive films 118 can maintain a stable adhesive force between the two flow field plates 100, so as to keep the contact resistance substantially constant;(2) At least 10% of the height of the third webs 117b, measured from the upper end 117b1, is formed by the third patterns, so that the third electrically conductive adhesive films 118 form at least a part of the second flow field 115 used to circulate the cooling fluid, which contributes to reducing or even eliminating the punching work required in the manufacture of the second flow field 115 of the flow field plate 100 and increases the flexibility with regard to design and manufacture of the flow field plate 100.;

[0043] The third electrically conductive adhesive films 118 comprise a third adhesive material and second electrically conductive particles distributed on the third adhesive material. The second electrically conductive particles can be distributed on the third adhesive material using any suitable method in any suitable weight percentage. This depends specifically on the conductive properties of the third adhesive material itself as well as on the density and conductivity of the second electrically conductive particles. The third adhesive material is preferably a phenolic resin or an epoxy resin. The second electrically conductive particles are preferably expanded graphite or another highly conductive carbon material.

[0044] It is conceivable that in some embodiments, the third zone of the metal plate 101 corresponding to the second flow field 115 is substantially planar. The third patterns are glued to the third zone and arranged such that the entire height of the third ridges 117b measured from the upper end 117b1 is formed by the third patterns. In other words, the third patterns are arranged such that the entire height of the third ridges 117b measured from the upper end 117b1 is formed by the third patterns, and the step of gluing the cut-out third patterns on the second side 101b to the metal plate 101 comprises gluing the cut-out third patterns on the second side 101b to the third zone of the metal plate 101 to thereby form the entire third ridges 117b.It should be understood that, as previously described in connection with the reaction zone 107, the method described here makes it easy and cost-effective to form the flow channel structures and flow channel patterns of the second flow field 115 used to circulate the cooling fluid, which are difficult to form using conventional methods such as punching and machining. Furthermore, it should be understood that in other embodiments, a portion of the third webs 117b may be formed by punching the metal plate 101 (for example, simultaneously with the punching of the first webs 107b), and the other portion of the third webs 117b may be formed by adhering the third electrically conductive adhesive film 118 to this portion. In this way, the entire third webs 117b may be formed.

[0045] The flow field plates 100 manufactured according to the method described above can be used as an anode plate or as a cathode plate. As shown in Fig.1, the anode plate of one fuel cell unit 1 of two adjacent fuel cell units 1 can be connected to the cathode plate of the other fuel cell unit 1 before assembling the cell stack, thus forming a bipolar plate. In other words, the cathode plate and anode plate produced using the method described above can be connected to one another in such a way that the first flow fields 103 are located back to back, thus forming a bipolar plate. In some embodiments, the cathode plate and the anode plate can each have a second flow field 115 for circulating a cooling fluid, and the second flow field 115 of the cathode plate and the second flow field 115 of the anode plate can cooperate to jointly form a flow field for circulating the cooling fluid.In other embodiments, only one of the cathode plate and the anode plate may have a second flow field 115 for circulating a cooling fluid, and this second flow field 115 serves on the cathode plate and the anode plate to circulate the cooling fluid.

[0046] In some embodiments, with respect to one and the same bipolar plate, the entire height of the first webs 107b of the first flow field 103 of the cathode plate is formed by the first electrically conductive adhesive films 111, and 10% to 50% (e.g., 10%, 20%, 30%, 40%, 50%, or any value therebetween) of the height of the first webs 107b of the first flow field 103 of the anode plate, measured from the upper end 107b1, is formed by the first electrically conductive adhesive films 111. In this case, the remaining part of the first webs 107b of the first flow field 103 of this anode plate is formed by stamping. Simultaneously with the formation of the remaining part of the first webs 107b, at least a part of the second flow field 115 serving to circulate the cooling fluid can be formed on the second side 101b of this anode plate opposite the first side 101a with the first flow field 103 formed.The first flow field 103 of the cathode plate serves as the cathode flow field, and the first flow field 103 of the anode plate serves as the anode flow field. During the reaction, the cathode-side reaction products contain water, which must be quickly drained from the reaction zone 107 via the cathode flow field. It is advantageous to form the entire height of the first webs 107b of the first flow field 103 (cathode flow field) of the cathode plate with the first electrically conductive adhesive films 111, since this creates various flow channel structures in the cathode flow field that promote water drainage, whereas such flow channel structures are difficult to form using the conventional stamping process.

[0047] This text discloses a method for manufacturing a flow field plate for a fuel cell assembly, a method for manufacturing a bipolar plate for a fuel cell, a flow field plate for a fuel cell assembly, and a bipolar plate for a fuel cell. Further examples and combinations thereof are as follows: Example 1 includes a method for manufacturing a flow field plate for a fuel cell unit, the method comprising: forming, on the first side of a metal plate, a first flow field for circulating a reaction fluid, wherein the reaction zone of the first flow field has first webs defining first flow channels. Forming the first flow field comprises the following steps: cutting out first patterns of first electrically conductive adhesive films corresponding to said first webs; and gluing said cut-out first patterns on the first side to the metal plate so that at least 10% of the height of the first webs, measured from the upper end, is formed by the first patterns. Example 2 includes the method of Example 1, wherein forming the first flow field further comprises the step of forming the first portion of the first lands by punching the metal plate; and the step of adhering the cut-out first patterns on the first side to the metal plate comprises adhering the cut-out first patterns to the first portion to thereby form the entire first lands. Example 3 includes the method of Example 1, wherein the first zone of the metal plate corresponding to the reaction zone is substantially planar, the first patterns are arranged such that the entire height of the first lands measured from the upper end is formed by the first patterns; the step of adhering the cut-out first patterns on the first side to the metal plate comprises adhering the cut-out first patterns on the first side to the first zone of the metal plate so as to form the entire first lands. Example 4 includes the method of Example 1, wherein each of the first flow channels is defined by two side walls and a bottom wall extending between the two side walls, the two side walls are formed by two adjacent first webs, and the bottom wall is formed by the part of the metal plate located between the two adjacent first webs, wherein the first patterns do not overlap the part of the metal plate. Example 5 includes the method of Example 1, wherein the first electrically conductive adhesive films comprise a first adhesive material and first electrically conductive particles distributed on the first adhesive material. Example 6 includes the method of Example 5, wherein the first adhesive material is PMMA, acrylic adhesive, polypyrrole, epoxy resin, silicone resin, polyamide, polyimide, or fluororubber; and / or the first electrically conductive particles are gold, graphite, Ketjen black, carbon black, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, chromium nitride, or titanium nitride. Example 7 includes the method of Example 1, wherein the fuel cell assembly further comprises a membrane electrode assembly with a diffusion layer, wherein the first electrically conductive adhesive films are configured to adhere the metal plate to the diffusion layer such that an adhesive force of at least 2 N / cm is provided between the diffusion layer and the metal plate. Example 8 includes the method of Example 1, wherein the step of cutting out first patterns corresponding to the first webs from the first electrically conductive adhesive films comprises applying the first electrically conductive adhesive films between two layers of backing film to form a layer structure and cutting out the first patterns corresponding to the first webs from the layer structure, wherein the step of adhering the cut-out first patterns on the first side to the metal plate comprises detaching the cut-out first patterns from the backing films and adhering the same on the first side to the metal plate. Example 9 includes a method of any one of Examples 1 to 8, wherein the metal plate further comprises an inlet arranged to receive the reaction fluid and an outlet arranged to discharge reaction products; the first flow field further comprises an inlet distribution zone for connection to the inlet and an outlet collection zone for connection to the outlet, the reaction zone extends between the inlet distribution zone and the outlet collection zone, and at least one of the inlet distribution zone and the outlet collection zone comprises second webs delimiting second flow channels.Forming the first flow field further comprises the following steps: cutting out second patterns corresponding to the second webs from second electrically conductive adhesive films; and bonding the cut-out second patterns on the first side to the metal plate so that at least a part of the height of the second webs, measured from the upper end, is formed by the second patterns. Example 10 includes the method of Example 9, wherein the second zone of the metal plate corresponding to at least one of the input distribution zone and the output collection zone is substantially planar, the second patterns being arranged such that the entire height of the second lands measured from the top end is formed by the second patterns; and the step of adhering the cut-out second patterns on the first side to the metal plate comprises adhering the cut-out second patterns on the first side to the second zone of the metal plate so as to form the entire second lands. Example 11 includes the process of Example 10, wherein the second adhesive films are PEN, PET or PI films coated on the surface with acrylic adhesive. Example 12 includes a method from any one of Examples 1 to 8, the method further comprising forming, on the second side of the metal plate opposite the first side, a second flow field for circulating a cooling fluid, the second flow field comprising third webs defining third flow channels. Forming the second flow field comprises the following steps: cutting out third patterns corresponding to the third webs from third electrically conductive adhesive films; and bonding the cut-out second patterns to the metal plate on the first side so that at least 10% of the height of the third webs, measured from the upper end, is formed by the third patterns. Example 13 includes the method of Example 12, wherein the third zone of the metal plate corresponding to the second flow field is substantially planar, and the third patterns are arranged such that the entire height of the third lands measured from the top end is formed by the third patterns; and the step of adhering the cut-out third patterns on the second side to the metal plate comprises adhering the cut-out third patterns on the second side to the third zone of the metal plate so as to form the entire third lands. Example 14 includes the method of Example 12, wherein the third electrically conductive adhesive films comprise a third adhesive material and second electrically conductive particles distributed on the third adhesive material, the third adhesive material is preferably a phenolic resin or epoxy resin, and the second electrically conductive particles are preferably expandable graphite. Example 15 includes a method of manufacturing a bipolar plate for a fuel cell, the method comprising: using the method of Example 1 to manufacture a cathode plate; using the method of Example 1 to manufacture an anode plate; and joining the cathode plate and the anode plate in a manner such that the first flow fields are back-to-back to each other to form a bipolar plate. Example 16 includes the method of Example 15, wherein the entire height of the first webs of the first flow field of the cathode plate is formed by the first electrically conductive adhesive films; and 10% to 50% of the height of the first webs of the anode plate, measured from the upper end, is formed by the first electrically conductive adhesive films. Example 17 includes a flow field plate for a fuel cell unit, the flow field plate comprising: a metal plate; a first flow field formed on the first side of the metal plate and serving to circulate a reaction fluid, wherein the reaction zone of the first flow field has first webs defining first flow channels; and first electrically conductive adhesive films, wherein the first electrically conductive adhesive films take the form of first patterns corresponding to the first webs and are adhered to the metal plate on the first side so that at least 10% of the height of the first webs, measured from the upper end, is formed by the first patterns. Example 18 includes the flow field plate of Example 17, wherein the first webs consist of a first part and a second part, wherein the first part is formed by punching the metal plate and the second part is formed by adhering the first electrically conductive adhesive films to the first part. Example 19 includes the flow field plate of Example 17, wherein the first zone of the metal plate corresponding to the reaction zone is substantially planar, and the first electrically conductive adhesive films are adhered to the first zone and arranged such that the entire height of the first lands measured from the upper end is formed by the first patterns. Example 20 includes the flow field plate of Example 17, wherein each of the first flow channels is defined by two side walls and a bottom wall extending between the two side walls, the two side walls are formed by two adjacent first webs, and the bottom wall is formed by the second part of the metal plate located between the two adjacent first webs, wherein the first patterns do not overlap the second part of the metal plate. Example 21 includes the flow field plate of Example 17, wherein the first electrically conductive adhesive films comprise a first adhesive material and first electrically conductive particles distributed on the first adhesive material. Example 22 includes the flow field plate of Example 21, wherein the first adhesive material is PMMA, acrylic adhesive, polypyrrole, epoxy resin, silicone resin, polyamide, polyimide, or fluororubber and / or the first electrically conductive particles are gold, graphite, Ketjen black, carbon black, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, chromium nitride, or titanium nitride. Example 23 includes the flow field plate of Example 17, wherein the fuel cell assembly further comprises a membrane electrode assembly with a diffusion layer, wherein the first electrically conductive adhesive films are configured to adhere the metal plate to the diffusion layer to provide an adhesive force of at least 2 N / cm between the diffusion layer and the metal plate. Example 24 includes the flow field plate of Example 17, wherein the flow field plate further comprises an inlet arranged to receive the reaction fluid and an outlet arranged to discharge reaction products; the first flow field further comprises an inlet distribution zone for connection to the inlet and an outlet collection zone for connection to the outlet, the reaction zone extends between the inlet distribution zone and the outlet collection zone and comprises at least one second web delimiting second flow channels from the inlet distribution zone and the outlet collection zone; the flow field plate further comprises second adhesive films, wherein the second adhesive films take the form of second patterns corresponding to the second webs and are adhered to the metal plate on the first side so that at least part of the height of the second webs, measured from the upper end, is formed by the second patterns. Example 25 includes the flow field plate from Example 24, wherein the second adhesive films are PEN, PET or PI films coated on the surface with acrylic adhesive. Example 26 includes the flow field plate of Example 17, wherein the second zone of the metal plate corresponding to at least one of the input distribution zone and the output collection zone is substantially planar, and the second adhesive films are adhered to the second zone and arranged such that the entire height of the second lands measured from the top end is formed by the second patterns. Example 27 includes the flow field plate of Example 17, the flow field plate further comprising: a second flow field formed on the second side of the metal plate opposite the first side and serving to circulate a cooling fluid, the second flow field comprising third webs defining third flow channels; and third electrically conductive adhesive films, the third electrically conductive adhesive films taking the form of third patterns corresponding to the third webs and being adhered to the metal plate on the second side so that at least 10% of the height of the third webs, measured from the upper end, is formed by the third patterns. Example 28 includes the flow field plate of Example 27, wherein the third electrically conductive adhesive films comprise a third adhesive material and second electrically conductive particles distributed on the third adhesive material, the third adhesive material is preferably a phenolic resin or epoxy resin, and the second electrically conductive particles are preferably expandable graphite. Example 29 includes the flow field plate of Example 17, wherein the third zone of the metal plate corresponding to the second flow field is substantially planar, and the third patterns are bonded to the third zone and arranged such that the entire height of the third lands measured from the upper end is formed by the third patterns. Example 30 includes a bipolar plate for a fuel cell, the bipolar plate comprising: an anode plate, wherein the anode plate is a flow field plate according to Example 11; a cathode plate, wherein the cathode plate is a flow field plate according to Example 11; wherein the anode plate and the cathode plate are joined together in a manner such that the first flow fields are back-to-back with each other. Example 31 includes the bipolar plate of Example 30, wherein the entire height of the first webs of the first flow field of the cathode plate is formed by the first electrically conductive adhesive films and 10% to 50% of the height of the first webs of the anode plate, measured from the upper end, is formed by the first electrically conductive adhesive films.

[0048] It should be understood that the terms “first”, “second” and “third” are used only to distinguish one component or part from another component or part, but are not intended to limit such components and / or parts.

[0049] The present application has been described in detail above using specific embodiments. It is obvious that all descriptions mentioned and embodiments illustrated in the figures are to be understood as exemplary and do not represent a limitation of the present application. Those skilled in the art may, without departing from the spirit of the present application, make various variations or modifications thereto, which do not depart from the scope of the present application.

Claims

[1] A method of manufacturing a flow field plate for a fuel cell unit, comprising: Forming on the first side of a metal plate a first flow field serving to circulate a reaction fluid, wherein the reaction zone of the first flow field has first webs delimiting first flow channels, wherein the formation of the first flow field comprises the following steps: Cutting out first patterns corresponding to the first webs from first electrically conductive adhesive films; and Glue the cut-out first patterns on the first side to the metal plate so that at least 10% of the height of the first webs, measured from the top end, is formed by the first patterns. [2] Method according to claim 1, characterized by , that: the formation of the first flow field further comprises the step of forming the first part of the first webs by punching the metal plate, wherein the step of adhering the cut-out first patterns on the first side to the metal plate comprises adhering the cut-out first patterns to the first part of the first webs to form the entire first webs; or the first zone of the metal plate corresponding to the reaction zone is substantially planar and the first patterns are arranged such that the entire height of the first webs measured from the upper end is formed by the first patterns, wherein the step of adhering the cut-out first patterns on the first side to the metal plate comprises adhering the cut-out first patterns on the first side to the first zone so as to form the entire first webs. [3] Method according to claim 1, characterized by , that: the first electrically conductive adhesive films comprise a first adhesive material and first electrically conductive particles distributed on the first adhesive material, wherein the first adhesive material is preferably PMMA, acrylic adhesive, polypyrrole, epoxy resin, silicone resin, polyamide, polyimide, or fluororubber, and the first electrically conductive particles are preferably gold, graphite, Ketjen black, carbon black, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, chromium nitride, or titanium nitride; and / or each of the first flow channels is delimited by two side walls and a bottom wall extending between the two side walls, the two side walls are formed by two adjacent first webs, and the bottom wall is formed by the part of the metal plate located between the two adjacent first webs, wherein the first patterns do not overlap the part of the metal plate. [4] Method according to claim 1, characterized by , that: the fuel cell unit further comprises a membrane electrode assembly with a diffusion layer, wherein the first electrically conductive adhesive films are configured such that the metal plate is bonded to the diffusion layer such that an adhesive force of at least 2 N / cm is provided between the diffusion layer and the metal plate; and / or the step of cutting out first patterns corresponding to the first webs from the first electrically conductive adhesive films comprises applying the first electrically conductive adhesive films between two layers of backing film to form a layer structure and cutting out the first patterns corresponding to the first webs from the layer structure, wherein the step of adhering the cut-out first patterns on the first side to the metal plate comprises detaching the cut-out first patterns from the backing films and adhering the same on the first side to the metal plate. [5] Method according to one of claims 1 to 4, characterized by that the metal plate further comprises an inlet arranged to receive the reaction fluid and an outlet arranged to discharge reaction products; the first flow field further comprises an inlet distribution zone for connection to the inlet and an outlet collection zone for connection to the outlet, the reaction zone extends between the inlet distribution zone and the outlet collection zone, at least one of the inlet distribution zone and the outlet collection zone comprises second webs delimiting second flow channels, and the formation of the first flow field further comprises the following steps: Cutting out second patterns corresponding to the second webs from second electrically conductive adhesive films, wherein the second adhesive films are preferably PEN, PET or PI films coated on the surface with acrylic adhesive; and Glue the cut-out second patterns on the first side to the metal plate so that at least part of the height of the second webs, measured from the upper end, is formed by the second patterns. [6] Method according to claim 5, characterized by , that: the second zone of the metal plate corresponding to at least one of the input distribution zone and the output collection zone is substantially flat, wherein the second patterns are arranged so that the total height of the second webs measured from the upper end is formed by the second patterns; and the step of gluing the cut-out second patterns on the first side to the metal plate comprises gluing the cut-out second patterns on the first side to the second zone of the metal plate so as to form the entire second webs. [7] Method according to one of claims 1 to 4, characterized bythat the method further comprises forming, on the second side of the metal plate opposite the first side, a second flow field serving to circulate a cooling fluid, wherein the second flow field comprises third webs delimiting third flow channels, wherein the formation of the second flow field comprises the following steps: Cutting out third patterns corresponding to the third webs from third electrically conductive adhesive films, wherein the third electrically conductive adhesive films comprise a third adhesive material and second electrically conductive particles distributed on the third adhesive material, wherein the third adhesive material is preferably a phenolic resin or epoxy resin and the second electrically conductive particles are preferably expanded graphite; and Glue the cut-out third patterns on the second side to the metal plate so that at least 10% of the height of the third webs, measured from the top end, is formed by the third patterns. [8] Method according to claim 7, characterized by , that: the third zone of the metal plate corresponding to the second flow field is substantially flat and the third patterns are arranged such that the entire height of the third webs measured from the upper end is formed by the third patterns; and the step of gluing the cut-out third patterns on the second side to the metal plate comprises gluing the cut-out third patterns on the second side to the third zone of the metal plate so as to form the entire third webs. [9] A method of manufacturing a bipolar plate for a fuel cell, comprising: Use of the method according to claim 1 for producing a cathode plate; Use of the method according to claim 1 for producing an anode plate; and Connecting the cathode plate and the anode plate in such a way that the first flow fields are back to back to form a bipolar plate. [10] Method according to claim 9, characterized by , that: the entire height of the first webs of the first flow field of the cathode plate is formed by the first electrically conductive adhesive films; and 10% to 50% of the height of the first webs of the anode plate, measured from the upper end, are formed by the first electrically conductive adhesive films. [11] Flow field plate for a fuel cell unit, comprising: a metal plate; a first flow field formed on the first side of the metal plate and serving to circulate a reaction fluid, wherein the reaction zone of the first flow field has first webs delimiting first flow channels; and first electrically conductive adhesive films, wherein the first electrically conductive adhesive films take the form of first patterns corresponding to the first webs and are glued to the metal plate on the first side so that at least 10% of the height of the first webs, measured from the upper end, is formed by the first patterns. [12] Flow field plate according to claim 11, characterized by , that: the first webs consist of a first part and a second part, wherein the first part is formed by punching the metal plate and the second part is formed by gluing the first electrically conductive adhesive films to the first part; or the first zone of the metal plate corresponding to the reaction zone is substantially planar, the first electrically conductive adhesive films are bonded to the first zone and arranged such that the entire height of the first webs measured from the upper end is formed by the first patterns. [13] Flow field plate according to claim 11, characterized by , that: the first electrically conductive adhesive films comprise a first adhesive material and first electrically conductive particles distributed on the first adhesive material, wherein the first adhesive material is preferably PMMA, acrylic adhesive, polypyrrole, epoxy resin, silicone resin, polyamide, polyimide, or fluororubber, and the first electrically conductive particles are preferably gold, graphite, Ketjen black, carbon black, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, chromium nitride, or titanium nitride; and / or each of the first flow channels is delimited by two side walls and a bottom wall extending between the two side walls, the two side walls are formed by two adjacent first webs, and the bottom wall is formed by the second part of the metal plate located between the two adjacent first webs, wherein the first patterns do not overlap the second part of the metal plate; and / or the fuel cell unit further comprises a membrane electrode assembly with a diffusion layer, and the first electrically conductive adhesive films are configured such that the metal plate is bonded to the diffusion layer such that an adhesive force of at least 2 N / cm is provided between the diffusion layer and the metal plate. [14] Flow field plate according to claim 11, characterized by , that: the flow field plate further comprises an inlet arranged to receive the reaction fluid and an outlet arranged to discharge reaction products; the first flow field further comprises an inlet distribution zone for connection to the inlet and an outlet collection zone for connection to the outlet, the reaction zone extends between the inlet distribution zone and the outlet collection zone and comprises at least one second web defining second flow channels between the inlet distribution zone and the outlet collection zone; the flow field plate further comprises second adhesive films, wherein the second adhesive films take the form of second patterns corresponding to the second webs and are glued to the metal plate on the first side so that at least a part of the height of the second webs, measured from the upper end, is formed by the second patterns; and the second adhesive films are preferably PEN, PET or PI films coated on the surface with acrylic adhesive. [15] Flow field plate according to claim 14, characterized by , that: the second zone of the metal plate corresponding to at least one of the input distribution zone and the output collection zone is substantially flat and the second adhesive films are glued to the second zone and arranged so that that the total height of the second webs measured from the upper end is formed by the second patterns. [16] Flow field plate according to claim 11, characterized by that the flow field plate further comprises: a second flow field formed on the second side of the metal plate opposite the first side and serving to circulate a cooling fluid, wherein the second flow field comprises third webs defining second flow channels; and third electrically conductive adhesive films, wherein the third electrically conductive adhesive films take the form of third patterns corresponding to the third webs and are glued to the metal plate on the second side so that at least 10% of the height of the third webs, measured from the upper end, is formed by the third patterns, wherein the third electrically conductive adhesive films comprise a third adhesive material and second electrically conductive particles distributed on the third adhesive material, the third adhesive material is preferably a phenolic resin or epoxy resin and the second electrically conductive particles are preferably expandable graphite. [17] Flow field plate according to claim 16, characterized by , that: the third zone of the metal plate corresponding to the second flow field is substantially planar and the third patterns are glued to the third zone and arranged such that the entire height of the third webs measured from the upper end is formed by the third patterns. [18] Bipolar plate for a fuel cell, comprising: an anode plate, wherein the anode plate is a flow field plate according to claim 11; a cathode plate, wherein the cathode plate is a further flow field plate according to claim 11; wherein the anode plate and the cathode plate are connected to each other in such a way that the first flow fields lie with the back sides to each other. [19] Bipolar plate according to claim 18, characterized by , that: the entire height of the first webs of the first flow field of the cathode plate is formed by the first electrically conductive adhesive films; and 10% to 50% of the height of the first webs of the anode plate, measured from the upper end, are formed by the first electrically conductive adhesive films.

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