Bipolar plate for fuel cells

Abstract

Bipolar plate (200) for fuel cells (330), comprising: a first plate-shaped half-shell (100) with a first half-shell edge (115); a second plate-shaped half-shell (105) with a second half-shell edge (195); wherein the first plate-shaped half-shell (100) and the second plate-shaped half-shell (105) are arranged one on top of the other in such a way that a force-locking connection is formed between the first half-shell edge (115) and the second half-shell edge (195), and that at least in sections a mechanical contact surface is formed between the first half-shell edge (115) and the second half-shell edge (195); two inlet openings through which an oxidant and a fuel gas can be supplied to the bipolar plate; two outlet openings through which residual gases of the supplied oxidant and the supplied fuel gas can be discharged from the bipolar plate; wherein the two inlet openings and the two outlet openings are formed by the first plate-shaped half-shell (100) lying on top of the second plate-shaped half-shell (105).

Description

[0001] The present invention relates to a bipolar plate for fuel cells, a fuel cell system, an electrically driven system and a method for producing a bipolar plate.

[0002] Various types of fuel cells are known, for example, those with a polymer electrolyte membrane (PEM) fuel cell, which uses hydrogen as fuel. A fuel cell consists of electrodes, an anode, and a cathode, between which an electrolyte, particularly in the form of a proton-conducting membrane, is arranged. These components form a so-called membrane electrode assembly (MEA for short).

[0003] Since the electrical voltage of a single fuel cell is limited, several fuel cells are connected in series to form a "stack" in order to enable a correspondingly higher voltage. The individual MEAs are separated from each other by bipolar plates, with the bipolar plates connecting the anodes and cathodes of consecutive MEAs to form the series connection. A bipolar plate is responsible for supplying hydrogen and oxidant (especially air or oxygen), removing water, and cooling the fuel cell stack. In addition, the bipolar plate collects the electrodes released from the hydrogen on the anode (hydrogen) side and finally feeds them to the oxidant on the cathode (oxygen) side.

[0004] A bipolar plate can be manufactured from two half-shells that are electrically connected to each other. A cooling medium or fluid can be conducted through cavities, channels, or conduits between the half-shells. A channel structure can be formed on the surfaces facing away from each other, i.e., the anode and cathode sides, to conduct the hydrogen or oxygen to the MEA (usually via a corresponding gas diffusion layer).

[0005] The two half-shells can be connected to each other at their outer edges by a seal. Attaching the seal is a complex manufacturing process, especially in a fuel cell stack with a large number of bipolar plates.

[0006] The present invention is based on the object of providing a bipolar plate which is improved in relation to the aforementioned problem.

[0007] This object is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0008] A first aspect of the solution relates to a bipolar plate for fuel cells, comprising: (i) a first plate-shaped half-shell with a first half-shell edge; (ii) a second plate-shaped half-shell with a second half-shell edge; (iii) wherein the first plate-shaped half-shell and the second plate-shaped half-shell are arranged one on top of the other, such that a force-locking connection is formed between the first half-shell edge and the second half-shell edge, and such that at least in sections a mechanical contact surface is formed between the first half-shell edge and the second half-shell edge; (iv) two inlet openings, through each of which an oxidizing agent and a fuel gas can be supplied to the bipolar plate; (v) two outlet openings, through each of which residual gases of the supplied oxidizing agent and the supplied fuel gas can be discharged from the bipolar plate;(vi) wherein the two inlet openings and the two outlet openings are formed by the first plate-shaped half-shell being superimposed on the second plate-shaped half-shell;

[0009] The terms "comprises," "includes," "includes," "has," "has," "with," or any other variation thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or that are inherent in such a method or apparatus.

[0010] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" rather than an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0011] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0012] The term “plurality” as used here shall mean “two or more”.

[0013] The term “configured” or “set up” to fulfil a specific function (and respective variations thereof), as used here, is to be understood that the corresponding device is already in a design or setting in which it can perform the function or is at least adjustable – i.e. configurable – so that it can perform the function after being set accordingly. The configuration can be carried out, for example, by appropriately setting parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, so that the configuration can be carried out by selecting one of these configurations or operating modes.

[0014] The term "fuel cell" as used here refers in particular to a device in which chemical energy is directly converted into electrical energy through an electrochemical reaction of a fuel with an oxidizing agent. For this purpose, an electrolyte layer can be provided in the fuel cell between two layers designed as electrodes. The electrolyte layer is designed, for example, as a polymer electrolyte membrane (PEM), which must be moist during operation in order to be able to conduct protons. A fuel, for example hydrogen, is dissociated at an electrode provided as the anode. The resulting protons can diffuse through the PEM to the electrode used as the cathode, where they react with an oxygen atom of the oxidizing agent reduced by the cathode, forming water (formally: 2H + + ½O2 - → H2O).

[0015] The term "substantially rectangular" as used here refers in particular to a rectangular shape, in particular an elongated rectangular shape, which may, in particular, have pointed corners or rounded corners. In particular, such a rectangular shape may also have recesses along its perimeter.

[0016] The term "electrical conductivity" or "electrically conductive" (and variations thereof) as used here refers to a physical quantity that indicates the ability of a substance to conduct electrical current. "Electrically conductive" within the meaning of the disclosure is therefore understood in particular to mean an electrical conductivity that is at least 100 S / m (at 25°C).

[0017] The bipolar plate according to the first aspect makes it possible to achieve that, due to the force-locking connection and the partial mechanical contact surface between the first half-shell edge and the second half-shell edge, no seal is applied in this area, and accordingly, this seal can be dispensed with. This simplifies and accelerates the manufacturing process for such a bipolar plate, since the application of the seal in the described contact surface is not necessary.

[0018] Preferred embodiments of the bipolar plate are described below, which can be combined with each other as well as with the other aspects described, unless this is expressly excluded or is technically impossible.

[0019] In some embodiments, each of the two inlet openings is formed from a first inlet recess in the first plate-shaped half-shell and a first inlet recess in the second plate-shaped half-shell resting thereon, wherein a first circumferential seal is arranged between the first inlet recesses of the first plate-shaped half-shell and the first inlet recesses of the second plate-shaped half-shell to seal the respective first inlet opening. This prevents gas flowing through the respective inlet opening from escaping between the inlet recesses of the first plate-shaped half-shell and the second plate-shaped half-shell.

[0020] In some embodiments, each of the two outlet openings is formed from a first outlet recess in the first plate-shaped half-shell and a first outlet recess in the second plate-shaped half-shell resting thereon, wherein a second circumferential seal is arranged between the first outlet recesses of the first plate-shaped half-shell and the first outlet recesses of the second plate-shaped half-shell to seal the respective first outlet opening. This prevents gas flowing through the respective outlet opening from escaping between the outlet recesses of the first plate-shaped half-shell and the second plate-shaped half-shell.

[0021] In some embodiments, the first plate-shaped half-shell and the second plate-shaped half-shell each have a substantially rectangular base body, which is each bordered by the first half-shell edge and the second half-shell edge. The mechanical contact surface is formed over the entire longitudinal sides of the first half-shell edge with the second half-shell edge of the rectangular base body by the first plate-shaped half-shell lying on top of the second plate-shaped half-shell. This makes it possible to dispense with the application of a seal between the two plate-shaped half-shells along both longitudinal sides. This allows for even more effective production of the bipolar plate.

[0022] In some embodiments, the bipolar plate has a cooling channel with an inlet and an outlet opening arranged at opposite edges of the rectangular base bodies of the first half-shell edge and the second half-shell edge, and wherein the two first inlet openings and the two first outlet openings each protrude beyond the opposite edges of the rectangular base bodies. As a result, a cooling fluid can be supplied to the cooling channel directly at the openings at the opposite edges of the rectangular base bodies, whereas an oxidizing agent and a fuel gas can be supplied through the inlet openings and outlet openings of the bipolar plate that protrude beyond the rectangular base bodies. As a result, an additional inlet opening and an additional outlet opening of the cooling channel that protrude beyond the opposite edges of the rectangular base bodies can be omitted.This enables a simplified bipolar plate.

[0023] In some embodiments, the first plate-shaped half-shell and / or the second plate-shaped half-shell are each formed from electrically conductive carbon, in particular graphite, and / or from an electrically conductive carbon composite material, in particular a thermoplastic material. Half-shells made of carbon, in particular graphite, exhibit good corrosion resistance and can be chemically stable under operating conditions in a fuel cell. Half-shells made of a carbon composite material are less brittle than half-shells made of carbon and are therefore easier to handle.

[0024] In some embodiments, the two inlet openings are spaced apart from each other and / or the two outlet openings are spaced apart from each other such that a cooling fluid can flow around each of the two inlet openings and / or each of the two outlet openings. This can prevent hydrogen, particularly from an internal outlet, from entering one of the inlet openings and / or one of the outlet openings during operation of a fuel cell.

[0025] A second aspect of the solution relates to a fuel cell system comprising: (i) a fuel cell stack having a plurality of fuel cells and having a plurality of bipolar plates according to the first aspect, wherein one of the plurality of bipolar plates is arranged between each two adjacent fuel cells; (ii) a container in which the fuel cell stack is arranged, and wherein the container can be filled with a cooling fluid so that the fuel cell stack can be surrounded by the cooling fluid.

[0026] In some embodiments, the fuel cell system comprises a clamping device, in particular one or more clamping bands, which is configured to exert a continuous mechanical force on the fuel cell stack in the stacking direction. The clamping device can press the first plate-shaped half-shell and the second plate-shaped half-shell of each bipolar plate together with the mechanical force. This enables the continuous formation of a force-locking connection and a mechanical contact surface between the respective first half-shell edges and the second half-shell edges lying thereon.

[0027] A third aspect of the solution relates to an electrically driven system comprising a fuel cell system according to the second aspect.

[0028] In some embodiments, the electrically powered system is designed as a motor vehicle, emergency power generator or power supply system.

[0029] A fourth aspect of the solution relates to a method for producing a bipolar plate for fuel cells, comprising: (i) providing a first plate-shaped half-shell with a first half-shell edge, and with two first inlet recesses and two first outlet recesses; (ii) providing a second plate-shaped half-shell with a second half-shell edge, and with second inlet recesses and two second outlet recesses;(iii) pressing the first plate-shaped half-shell together with the second plate-shaped half-shell with a mechanical force such that a force-locking connection is formed between the first half-shell edge and the second half-shell edge, and such that at least in sections a mechanical contact surface is formed between the first half-shell edge and the second half-shell edge, and such that the two first inlet recesses form two inlet openings with the second inlet recesses, and the two first outlet recesses form two outlet openings with the two second outlet recesses;

[0030] In some embodiments, before pressing together, a first circumferential seal is applied between the two first inlet recesses of the first plate-shaped half-shell and the two first inlet recesses of the second plate-shaped half-shell in order to seal the respective first inlet opening.

[0031] In some embodiments, before pressing together, a second circumferential seal is provided between the two first outlet recesses of the first plate-shaped half-shell and the two first outlet recesses of the second plate-shaped half-shell in order to seal the respective first outlet opening.

[0032] The features and advantages explained with regard to the first aspect of the solution also apply accordingly to the other aspects described.

[0033] Further advantages, features and possible applications emerge from the following description of preferred embodiments in conjunction with the figures.

[0034] This shows Fig. 1 schematically shows a plan view of a first plate-shaped half-shell according to an embodiment; Fig. 2A to 2C show schematically, in perspective and from the side, plate-shaped half-shells before and after their assembly according to an embodiment; Fig. 3 schematically shows a fuel cell system according to an embodiment; and Fig. 4 schematically shows a flow diagram according to an embodiment.

[0035] Throughout the figures, the same reference numerals are used for the same or corresponding elements.

[0036] In Fig. Figure 1 schematically shows a top view of a first plate-shaped half-shell 100 according to one embodiment. The first plate-shaped half-shell 100 has a rectangular base body 110 and a circumferential first half-shell edge 115 that encloses the rectangular base body 110.

[0037] The first plate-shaped half-shell 100 further has first inlet recesses 120, 130 and first outlet recesses 140, 150. These first inlet recesses 120, 130 and the first outlet recesses 140, 150 are each fluidically separated from one another and spaced apart from one another, so that coolant fluid can flow around each of these first inlet recesses 120, 130 on the one hand and around each of these first outlet recesses 140, 150 on the other. This can prevent hydrogen from entering these first inlet recesses 120, 130 and the first outlet recesses 140, 150 from an internal outlet.

[0038] The first inlet recesses 120, 130 are bordered by a first edge 125 and a second edge 135, respectively, and the first outlet recesses are bordered by a third edge 145 and a fourth edge 155, respectively. Fig. 1, the first inlet recesses 120, 130 and the first outlet recesses 140, 150 each have a rectangular shape. Other shapes are also conceivable, in particular rectangles with rounded corners. The first inlet recesses 120, 130 are each fluidically coupled to first channels 127 and second channels 133. Likewise, the outlet recesses 140, 150 are fluidically coupled to the first channels 127 and the second channels 133.

[0039] Furthermore, the first plate-shaped half-shell 100 has cooling channels 153 through which a cooling fluid can flow. These cooling channels 153 each have openings (not shown here) for the inflow and outflow of the cooling fluid at opposite edges of the first plate-shaped half-shell 100 with respect to the plane of the drawing. The opposing cooling channels 153 are fluidically coupled to one another to allow the cooling fluid to flow through the bipolar plate 200 in the assembled state.

[0040] The first plate-shaped half-shell 100 does not have any additional inlet opening and / or outlet opening for supplying or removing the cooling fluid.

[0041] Therefore, a bipolar plate 200 comprising the first plate-shaped half-shell 100 and the second plate-shaped half-shell 105 is suitable for being arranged in a housing 310 filled with a cooling fluid 320, thereby enabling a fluid exchange between this cooling fluid and the cooling fluid then flowing through the cooling channels 153, see Fig. 3.

[0042] In the Fig. 2A to 2C show two plate-shaped half-shells 100, 105 before and after their joining according to one embodiment.

[0043] In Fig. 2A, the first plate-shaped half-shell 100 is joined together from Fig. 1, with a second plate-shaped half-shell 105 in a perspective view. This is indicated by the dashed arrows. In Fig. 2A, for reasons of clarity, only the first half-shell edge 115, the first inlet recesses 120, 130 and the first outlet recesses 140, 150 are shown for the first plate-shaped half-shell 100. The Fig. However, the first plate-shaped half-shell 100 shown in Figure 2A is also intended to have all the features of the first plate-shaped half-shell 100 from Fig. 1.

[0044] Furthermore, Fig. 2A shows a second plate-shaped half-shell 105, which has a rectangular base body of the same size as the first plate-shaped half-shell 100. Furthermore, the second plate-shaped half-shell 105 has a second half-shell edge 195, second inlet recesses 160, 170, and second outlet recesses 180, 190. Likewise, the second plate-shaped half-shell 105 has features corresponding to the first plate-shaped half-shell 100, such as channels that are fluidically coupled to the second inlet recesses 160, 170 and the second outlet recesses 180, 190 (not shown here). These second inlet recesses 160, 170 and the second outlet recesses 180, 190 are each fluidically separated and spaced from each other so that coolant fluid can flow around each of these second inlet recesses 160, 170 on the one hand and around each of these second outlet recesses 180, 190.This can prevent hydrogen from an internal outlet from entering these second inlet recesses 160, 170 and the second outlet recesses 180, 190.

[0045] Before joining the first plate-shaped half-shell 100 to the second plate-shaped half-shell 105, a seal or sealing material is applied to the first edge 125, the second edge 135, the third edge 145, and the fourth edge 155 of the respective first inlet recesses 120, 130 and the first outlet recesses 140, 155. It is also conceivable to apply the seals to the edges of the second inlet recesses 160, 170 and the second outlet recesses 180, 190 before joining.

[0046] By joining, the first plate-shaped half-shell 100 and the second plate-shaped half-shell 105 come to rest on one another. As a result, the first inlet recesses 120, 130 come to rest on the second inlet recesses 160, 170, forming two inlet openings (not shown here). Through these inlet openings, an oxidizing agent, in particular oxygen, can be supplied via first channels 127 and a fuel gas, in particular hydrogen, can be supplied via second channels 137 to the bipolar plate 200 and ultimately to a fuel cell 330. The oxidizing agent and the fuel gas can flow separately from one another over a surface structure, in particular flow channels 127, 137, of the respective half-shells 100, 105, and can be supplied to a first electrode, in particular anode, and a second electrode, in particular cathode, of the membrane electrode assembly (not shown here) of the fuel cell 330.

[0047] Furthermore, by overlapping, the first outlet recesses 140, 150 come to rest on the second outlet recesses 180, 190, forming two outlet openings (not shown here). Residual gases from the oxidizing agent and the fuel gas can be discharged through these outlet openings.

[0048] During assembly, a first seal 210, 230 is formed between the first inlet recesses 120, 130 and the second inlet recesses 160, 170, and a second seal 220, 240 is formed between the first outlet recesses 140, 150 and the second outlet recesses 180, 190, see Fig. 2B and Fig. 2C. As a result, the two inlet openings and the two outlet openings are each sealed, so that when a gas flows through them, it cannot escape from the aforementioned inlet openings and outlet openings through the gaps between the respective recesses. Furthermore, when joined, a force-fit connection and a mechanical contact surface are formed between the first half-shell edge 115 and the second half-shell edge 195.

[0049] In the assembled state of a fuel cell stack with several fuel cells 330 and several bipolar plates 200 (see Fig. 3) the fuel cell stack can be compressed by a circumferential tensioning band 350 in the direction in which the fuel cells and the bipolar plates are arranged on top of one another to form a stack, thereby simultaneously enabling the first plate-shaped half-shell 100 to be pressed together with the second plate-shaped half-shell 105.

[0050] In the Fig. 2B and Fig. 2C shows a bipolar plate 200 in a side view. The side view of Fig. 2B for side view of Fig. 2C by 180° around the y-axis with respect to the schematically illustrated coordinate system. The bipolar plate 200 was formed by joining the first plate-shaped half-shell 100 with the second plate-shaped half-shell 105, as shown in Fig. 2A described, trained.

[0051] In the side view according to Fig. 2B, the bipolar plate 200 is shown with a first seal 210 disposed between the first inlet recess 130 and the second inlet recess 160, and with a second seal 220 disposed between the first outlet recess 140 and the second outlet recess 180.

[0052] In the side view according to Fig. 2C, the bipolar plate 200 is shown with a further first seal 230 disposed between the first inlet recess 120 and the second inlet recess 170, and a further second seal 240 disposed between the first outlet recess 150 and the second outlet recess 190.

[0053] In particular, the seals 210, 220, 230, 240 may each comprise epoxy resin or an epoxy adhesive with sealing effect or a silicone bead.

[0054] In Fig. 3 schematically shows a fuel cell system 300 according to one embodiment. The fuel cell system 300 has a housing 310 filled with a cooling fluid 320, in particular water. A fuel cell stack 340 with a plurality of fuel cells 330 and a plurality of bipolar plates 220 is shown in the housing 310. The illustration in Fig. 3 with two fuel cells 330 and three bipolar plates 200 is to be understood as an example. In particular, a fuel cell stack 340 can have significantly more fuel cells 330, in particular more than 100 fuel cells, and a corresponding number of bipolar plates 200. Regardless of the number of fuel cells 330 and the number of bipolar plates 200, a fuel cell 330 is arranged between two bipolar plates 200. An exception can be the termination of the fuel cell stack at both stack ends, here at the top and bottom in the plane of the drawing, by a separator plate or end plate (not shown here), i.e., no bipolar plate 200.Furthermore, the fuel cell stack 340 is clamped in the stacking direction by a tensioning band 350, whereby a mechanical force is exerted on the fuel cell stack 340 in the stacking direction, whereby the first plate-shaped half-shell 100 is pressed against the second plate-shaped half-shell 105, whereby a force-fitting connection and a mechanical contact surface are continuously formed between the respective first half-shell edges 105 and the second half-shell edges of the respective first plate-shaped half-shell 100 and second plate-shaped half-shell 105.

[0055] In Fig. 4 schematically shows a flow chart 400 for illustrating a preferred embodiment of a method for producing a bipolar plate 200.

[0056] In a first step S410 of the method, a first plate-shaped half-shell 100 with a first half-shell edge 115 and with two first inlet recesses 120, 130 and two first outlet recesses 140, 150 is provided.

[0057] In a further step S420 of the method, a second plate-shaped half-shell 105 with a second half-shell edge 195 and with second inlet recesses 160, 170 and two second outlet recesses 180, 190 is provided.

[0058] In a further step S430 of the method, the first plate-shaped half-shell 100 is pressed together with the second plate-shaped half-shell 105 using a mechanical force such that a force-locking connection is formed between the first half-shell edge 115 and the second half-shell edge 195, and such that a mechanical contact surface is formed at least in sections between the first half-shell edge 115 and the second half-shell edge 195, and such that the two first inlet recesses 120, 130 form two inlet openings with the second inlet recesses 160, 170, and the two first outlet recesses 140, 150 form two outlet openings with the two second outlet recesses 180, 190.

[0059] While at least one exemplary embodiment has been described above, it should be appreciated that a wide variety of variations exist. It should also be understood that the described exemplary embodiments are merely non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide one skilled in the art with guidance for implementing at least one exemplary embodiment, it being understood that various changes in the operation and arrangement of the elements described in an exemplary embodiment may be made without departing from the subject matter as defined in the appended claims, as well as their legal equivalents. LIST OF REFERENCE SYMBOLS 100, 105 First, second plate-shaped half-shell 110 Rectangular base body 115, 195 First, second half-shell edge 120, 130 First inlet recess 125, 135 First, second edge 127, 137 First, second channels 140, 150 First outlet recess 145, 155 Third, fourth edge 153 cooling channels 160, 170 Second inlet recess 180, 190 Second outlet recess 200 bipolar plates 210, 230 First seals 220, 240 Second seals 300 fuel cell system 310 housing 320 cooling fluid 330 fuel cell 340 fuel cell stacks 350 tensioning strap 400 Flowchart S410 Providing a first plate-shaped half-shell S420 Providing a second plate-shaped half-shell S430 Pressing together the first plate-shaped half-shell with the second plate-shaped half-shell

Claims

[1] Bipolar plate (200) for fuel cells (330), comprising: a first plate-shaped half-shell (100) with a first half-shell edge (115); a second plate-shaped half-shell (105) with a second half-shell edge (195); wherein the first plate-shaped half-shell (100) and the second plate-shaped half-shell (105) are arranged one on top of the other in such a way that a force-locking connection is formed between the first half-shell edge (115) and the second half-shell edge (195), and that at least in sections a mechanical contact surface is formed between the first half-shell edge (115) and the second half-shell edge (195); two inlet openings through which an oxidant and a fuel gas can be supplied to the bipolar plate; two outlet openings through which residual gases of the supplied oxidant and the supplied fuel gas can be discharged from the bipolar plate; wherein the two inlet openings and the two outlet openings are formed by the first plate-shaped half-shell (100) lying on top of the second plate-shaped half-shell (105). [2] Bipolar plate (200) according to claim 1, wherein each of the two inlet openings is formed from a first inlet recess (120, 130) of the first plate-shaped half-shell (100) and a first inlet recess (160, 170) of the second plate-shaped half-shell (105) resting thereon, wherein a first circumferential seal (210, 230) for sealing the respective first inlet opening is arranged between the first inlet recesses (120, 130) of the first plate-shaped half-shell (100) and the first inlet recesses (160, 170) of the second plate-shaped half-shell (105). [3] Bipolar plate (200) according to claim 1 or 2, wherein each of the two outlet openings is formed from a first outlet recess (140, 150) of the first plate-shaped half-shell (100) and a first outlet recess (180, 190) of the second plate-shaped half-shell (105) resting thereon, wherein a second circumferential seal (220, 240) for sealing the respective first outlet opening is arranged between the first outlet recesses (140, 150) of the first plate-shaped half-shell (100) and the first outlet recesses (180, 190) of the second plate-shaped half-shell (105). [4] Bipolar plate (200) according to one of the preceding claims, wherein the first plate-shaped half-shell (100) and the second plate-shaped half-shell (105) each have a substantially rectangular base body, which are each bordered by the first half-shell edge (115) and the second half-shell edge (195), wherein the mechanical contact surface is formed over the entire longitudinal sides of the first half-shell edge (115) with the second half-shell edge (195) of the rectangular base body by the first plate-shaped half-shell (100) lying on the second plate-shaped half-shell (105). [5] Bipolar plate (200) according to claim 4, comprising a cooling channel (153) with an inlet and an outlet opening arranged on opposite edges of the rectangular base bodies of the first half-shell edge (115) and the second half-shell edge (195), and wherein the two first inlet openings and the two first outlet openings each protrude beyond the opposite edges of the rectangular base bodies. [6] Bipolar plate (200) according to one of the preceding claims, wherein the first plate-shaped half-shell (100) and / or the second plate-shaped half-shell (105) are each formed from electrically conductive carbon and / or from an electrically conductive carbon composite material. [7] Bipolar plate (200) according to one of the preceding claims, wherein the two inlet openings are spaced apart from each other and / or the two outlet openings are spaced apart from each other such that a cooling fluid can flow around each of the two inlet openings and / or each of the two outlet openings. [8] Fuel cell system (300), comprising: a fuel cell stack (340) having a plurality of fuel cells (330) and having a plurality of bipolar plates (200) according to one of claims 1 to 7, wherein one of the plurality of bipolar plates (200) is arranged between each two adjacent fuel cells (330); a container (310) in which the fuel cell stack (340) is arranged, and wherein the container can be filled with a cooling fluid (320) so that the fuel cell stack (340) can be surrounded by the cooling fluid (320). [9] Fuel cell system (300) according to claim 8, comprising a clamping device (350) which is arranged to exert a continuous mechanical force on the fuel cell stack (340) in the stacking direction. [10] An electrically driven system comprising a fuel cell system (300) according to any one of claims 8 or 9. [11] Electrically driven system according to claim 10, which is designed as a motor vehicle, emergency power generator or power supply system. [12] A method for producing a bipolar plate (200) for fuel cells (330), comprising: Providing a first plate-shaped half-shell (100) with a first half-shell edge (115), and with two first inlet recesses (120, 130) and two first outlet recesses (140, 150); Providing a second plate-shaped half-shell (105) with a second half-shell edge (195), and with second inlet recesses (160, 170) and two second outlet recesses (180, 190); Pressing the first plate-shaped half-shell (100) together with the second plate-shaped half-shell (105) with a mechanical force such that that a force-locking connection is formed between the first half-shell edge (115) and the second half-shell edge (195), and that a mechanical contact surface is formed at least in sections between the first half-shell edge (115) and the second half-shell edge (195), and that the two first inlet recesses (120, 130) form two inlet openings with the two second inlet recesses (160, 170), and the two first outlet recesses (140, 150) form two outlet openings with the two second outlet recesses (180, 190). [13] Method according to claim 12, wherein, before the pressing together, a first circumferential seal (210, 230) is provided between the two first inlet recesses (120, 130) of the first plate-shaped half-shell (100) and the two first inlet recesses (160, 170) of the second plate-shaped half-shell (105) in order to seal the respective first inlet opening. [14] Method according to claim 12 or 13, wherein, before the pressing together, a second circumferential seal (220, 240) is provided between the two first outlet recesses (140, 150) of the first plate-shaped half-shell (100) and the two first outlet recesses (180, 190) of the second plate-shaped half-shell (105) in order to seal the respective first outlet opening.

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