Electrochemical cell system

Abstract

The invention relates to an electrochemical cell system (11) having an electrochemical cell unit (25) for converting electrochemical energy into electrical energy as a fuel cell unit (1) and / or for converting electrical energy into electrochemical energy as an electrolysis cell unit (6), comprising electrochemical cells (24) arranged in a stacked manner as a cell stack (10), a housing (13) for the cell stack (24), the cell stack (24) being arranged inside the housing (13), a subsystem (40) for the cell stack (24), and a fastening device (46) for fastening the subsystem (40) to the housing (13) of the cell stack (24), the subsystem (40) being fastened to the housing (13) by the fastening device (46), wherein the electrochemical cell unit (24) comprises a centring device (47) having a contact geometry (50) and a mating contact geometry (51) for positioning the subsystem (40) relative to the housing (13) for the cell stack (10).

Description

[0001] Description

[0002] title

[0003] Electrochemical cell system

[0004] The present invention relates to an electrochemical cell system according to the preamble of claim 1.

[0005] State of the art

[0006] Fuel cell units, as galvanic cells, convert continuously supplied fuel and oxidant into electrical energy and water through redox reactions at an anode and cathode. Fuel cells are used in a wide variety of stationary and mobile applications, for example, in homes without a power grid connection or in motor vehicles, in rail transport, aviation, aerospace, and shipping. In fuel cell units, a large number of fuel cells are arranged in a stack.

[0007] In fuel cell units, a large number of fuel cells are arranged in a fuel cell stack. Within each fuel cell, there is a gas space for the oxidant, i.e., a flow space for the passage of oxidant, such as ambient air with oxygen. The gas space for the oxidant is formed by channels on the bipolar plate and by a gas diffusion layer for a cathode. The channels are thus formed by a corresponding channel structure of a bipolar plate, and the oxidant, namely oxygen, passes through the gas diffusion layer to reach the cathode of the fuel cell. Similarly, a gas space for fuel is formed at an anode. Electrolysis cell units consisting of stacked electrolysis cells, similar to those in fuel cell units, are used, for example, for the electrolytic production of hydrogen and oxygen from water.Furthermore, fuel cell units are known that can be operated as reversible fuel cell units and thus as electrolysis cell units.

[0008] A fuel cell system with a fuel cell unit comprises an oxidant supply system, a fuel supply system, and a coolant supply system. An electrolysis cell system comprises an electrolyte supply system. Fuel cell systems and electrolysis cell systems form electrochemical cell systems. The oxidant supply system, the fuel supply system, the coolant supply system, and the electrolyte supply system each form a subsystem for an electrochemical cell system. The subsystem has a subsystem housing with a subsystem connection plate. The subsystem connection plate faces the electrochemical cell unit. The subsystem connection plate has an opening. The opening of the subsystem connection plate is sealed with a gasket between the electrochemical cell unit and the subsystem.The subsystem is attached to the electrochemical cell unit, in particular to the housing of the electrochemical cell unit, using a fastening device. Local pins, which are essentially point-shaped in cross-section, are formed on the subsystem and / or on the electrochemical cell unit for aligning and positioning the subsystem relative to the electrochemical cell unit. The pins and a bore in which the pins are arranged do not serve as a seal. Due to their design characteristics, the pins and the bore cannot be machined together with a support surface for the seal. The pins and the bore, on the one hand, and the support surface for the seal, on the other, must therefore be manufactured in separate operations, in particular by machining. This disadvantageously results in high costs.

[0009] EP 1 255660 81 discloses a device with a fuel cell for generating electrical energy and distributing the electrical energy to electrical consumers arranged in a high-voltage power grid connected to the fuel cell, and to further electrical consumers arranged in a low-voltage power grid connected to the high-voltage power grid via a DC-DC converter, characterized in that a central monitoring and switching unit has a housing which can be detachably fastened to the fuel cell housing, in which electrical conductors are arranged which are each connected to an electrical output of the fuel cell via feedthroughs in a housing wall and contact means, and at least one of which has a contact of a fuel cell circuit breaker, that the conductors are connected via branches which are provided with fuses on at least one pole,and bushings in a housing wall and contact means are connected to consumers and the low-voltage cable network is connected via a bushing to a control and evaluation unit belonging to the central monitoring and switching unit, the control and evaluation unit is connected via bushings in a housing wall and contact means to sensors for detecting operating states of the device and the bushings in the housing walls are dust- and watertight and the contact means are detachable.

[0010] EP 2 497 142 B1 shows a fuel cell arrangement comprising a main housing with a main housing interior that is gas-tight to the environment and in which at least one reformer, a reformer burner that supplies the reformer with thermal energy, and a fuel cell stack are located, wherein the main housing has at least one air connection, and wherein at least one fan is provided, which, during operation, draws air through the air connection into the main housing interior. The fuel cell stack is arranged in a fuel cell housing arranged within the main housing interior, which is adapted to the shape of the fuel cell stack so that it encloses the fuel cell stack with a small distance. The fuel cell housing has at least one intake opening connected to the main housing interior and at least one connection to an exhaust line connected to the intake side of the fan.and wherein a burner line connected to an inlet opening of the reformer burner is connected to the pressure side of the blower.,

[0011] Disclosure of the invention Advantages of the invention

[0012] An electrochemical cell system according to the invention having an electrochemical cell unit for converting electrochemical energy into electrical energy as a fuel cell unit and / or for converting electrical energy into electrochemical energy as an electrolysis cell unit, comprising stacked electrochemical cells as a cell stack, a housing for the cell stack and the cell stack arranged within the housing, a subsystem for the cell stack, a fastening device for fastening the subsystem to the housing of the cell stack and the subsystem being fastened to the housing with the fastening device, wherein the electrochemical cell unit comprises a centering device with a contact geometry and a counter-contact geometry for positioning the subsystem relative to the housing for the cell stack. An electrochemical cell system comprises an electrochemical cell unit and at least one subsystem.

[0013] In a further embodiment, the contact geometry is formed on a recess of the contact component and / or the mating contact geometry is formed on a projection of the mating contact component.

[0014] In an additional embodiment, the contact geometry is formed on a projection of the contact component and / or the mating contact geometry is formed on a recess of the mating contact component.

[0015] In a further embodiment, the recess is formed completely circumferentially, in particular annularly, on the contact component.

[0016] In an additional embodiment, the projection is formed completely circumferentially, in particular annularly, on the counter-contact component.

[0017] Preferably, the contact component is formed at least partially, in particular completely, in one piece with the housing for the cell stack and / or the mating contact component is formed at least partially, in particular completely, in one piece with a subsystem housing. Advantageously, the contact component is formed at least partially, in particular completely, in one piece with the subsystem housing and / or the mating contact component is formed at least partially, in particular completely, in one piece with the housing for the cell stack.

[0018] In a further embodiment, the contact component on the contact geometry and the counter-contact component on the counter-contact geometry lie on top of each other.

[0019] In an additional embodiment, the contact geometry and the mating contact geometry are aligned substantially, in particular with a deviation of less than 30°, 20° or 10°, parallel to a direction of movement of the subsystem during assembly and fastening of the subsystem to the housing as an axial direction.

[0020] In a further variant, the contact geometry and the mating contact geometry are aligned at an acute angle to a direction of movement of the subsystem during assembly and fastening of the subsystem to the housing as an axial direction, so that the contact geometry and the mating contact geometry are conical.

[0021] In a supplementary embodiment, the contact geometry and the counter-contact geometry are complementary to each other, in particular planar.

[0022] A seal is expediently formed between the contact component and the mating contact component, in particular between the contact geometry and the mating contact geometry, wherein the seal is formed in particular in a direction perpendicular to a circumferential direction between the contact geometry and the mating contact geometry.

[0023] In a further variant, the seal is designed to be completely circumferential, in particular annular. In an additional embodiment, the contact geometry and the counter-contact geometry are designed in the circumferential direction with a circumferential angle a of at least 30° or 90°, in particular completely circumferential with a circumferential angle of 360°.

[0024] In a supplementary embodiment, the subsystem comprises a subsystem housing and the subsystem for the electrochemical cell stack is arranged within the subsystem housing.

[0025] In an additional embodiment, the contact component and the counter-contact component are formed in the circumferential direction with a circumferential angle a of at least 30° or 90°, in particular completely circumferentially with a circumferential angle of 360°.

[0026] In a further embodiment, the projection is arranged in the recess, in particular completely circumferentially in the circumferential direction.

[0027] In an additional embodiment, the seal rests, in particular directly, on the contact geometry and / or the mating contact geometry. Therefore, no additional machining is required to support the seal, because the machined contact geometry and / or mating contact geometry is used for the seal support.

[0028] Preferably, the contact component is formed at least partially, in particular completely, by the housing for the cell stack and the counter-contact component is formed at least partially, in particular completely, by a subsystem housing.

[0029] Advantageously, the contact component is formed at least partially, in particular completely, by a subsystem housing and the counter-contact component is formed at least partially, in particular completely, by the housing for the cell stack.

[0030] In a further variant, the contact component is designed as a separate contact component, in particular in addition to the housing and / or the subsystem housing. In a further variant, the mating contact component is designed as a separate mating contact component, in particular in addition to the housing and / or the subsystem housing.

[0031] In an additional embodiment, the seal and / or the contact component and / or the mating contact component and / or the contact geometry and / or the mating contact geometry and / or the projection and / or the recess are formed in the circumferential direction with a circumferential angle a of at least 30° or 90°, in particular completely circumferentially with a circumferential angle a of 360°, and / or are formed in the region of the opening of the subsystem housing, in particular with a distance of less than 20 cm, 10 cm, 5 cm or 3 cm, from the opening of the subsystem housing.

[0032] In a supplementary variant, at least two seals and / or at least two contact components and / or at least two counter-contact components and / or at least two contact geometries and / or at least two counter-contact geometries and / or at least two projections and / or at least two recesses are formed for each subsystem.

[0033] In an additional embodiment, only one seal and / or only one contact component and / or only one counter-contact component and / or only one contact geometry and / or only one counter-contact geometry and / or only one projection and / or only one recess are formed for each subsystem.

[0034] In an additional embodiment, the distance of the seal and / or contact component and / or counter-contact component and / or contact geometry and / or counter-contact geometry to the boundary of the opening of the subsystem housing is less than 10 cm or 5 cm.

[0035] In a further variant, the contact component and the mating contact component are formed by the seal. Preferably, the opening of the subsystem housing is delimited by the subsystem housing, in particular by the subsystem connection plate.

[0036] In a supplementary variant, the seal is at least partially, in particular completely, made of an elastic material and / or of an elastomer and / or of plastic, preferably HPU and / or PU and / or NBR and / or FPM and / or FKM and / or EPDM and / or silicone and / or PTFE and / or POM and / or PA and / or PA 6 G and / or rubber.

[0037] Preferably, the diameter of the seal is greater than 1 mm, 3 mm or 5 mm.

[0038] In a supplementary variant, the seal and / or the contact component and / or the counter-contact component are formed completely continuous in the circumferential direction, in particular in a section perpendicular to the axial direction.

[0039] In a supplementary variant, the seal and / or the contact component and / or the counter-contact component are elliptical, in particular circular, or rectangular, in particular square, in particular in a section perpendicular to the axial direction.

[0040] In an additional variant, the length of the boundary of the opening on the subsystem housing in the circumferential direction essentially corresponds, in particular with a deviation of less than 30%, 20% or 10%, to the length of the seal and / or contact component and / or mating contact component and / or contact geometry and / or mating contact geometry in the circumferential direction.

[0041] In a further variant, the length of the seal and / or contact component and / or mating contact component and / or contact geometry and / or mating contact geometry in the circumferential direction corresponds to at least 10%, 30%, 50%, or 70% of the diameter, in particular the maximum diameter, of the subsystem. In a further variant, the length of the seal essentially corresponds, in particular with a deviation of less than 30%, 20%, or 10%, to the length of the contact component and / or mating contact component and / or contact geometry and / or mating contact geometry, in particular in the circumferential direction.

[0042] In a further embodiment, the seal is arranged, in particular exclusively, between the contact component and the counter-contact component.

[0043] In an additional embodiment, the seal is formed in one piece.

[0044] In a further embodiment, the electrochemical cell system comprises one seal, in particular only one seal, for sealing between a subsystem housing of each subsystem and the housing of the electrochemical cell unit.

[0045] The subsystem is preferably configured as an oxidant supply system, a fuel supply system, a coolant supply system, an electrolyte supply system, and / or an electrical system. The electrical system preferably serves to conduct electrical energy from and / or to the electrochemical cell unit.

[0046] Preferably, the electrical system comprises a battery and / or a transformer and / or an inverter and / or an AC / DC converter.

[0047] In a further embodiment, the direction of movement and / or axial direction for each subsystem is substantially, in particular with a deviation of less than 30°, 20°, or 0°, perpendicular to a wall, in particular a connection plate, of the housing of the electrochemical cell unit facing the respective subsystem, and preferably the respective subsystem is fastened to this wall of the housing with the fastening device and / or the contact component and / or counter-contact component is formed on this wall facing the respective subsystem. In a further embodiment, the seal is arranged in a groove.

[0048] Preferably, the groove for the seal is formed on the contact component and / or on the counter-contact component.

[0049] In an additional variant, the contact geometry and the counter-contact geometry are exclusively flat, in particular in the area of ​​contact between the contact geometry and the counter-contact geometry.

[0050] In a further embodiment, the fuel cell system comprises a fuel supply system with a pressure vessel for fuel as hydrogen as a process fluid and an oxidant supply system with a gas delivery device for oxidant as a process fluid.

[0051] In a supplementary variant, the fuel cell system comprises a fuel cell unit, a cooling system, an oxidant supply system and a fuel supply system.

[0052] In a further embodiment, the electrolysis cell system comprises an electrolysis cell unit and an electrolyte supply system.

[0053] Preferably the fuel is hydrogen, hydrogen-rich gas, reformate gas or natural gas.

[0054] Advantageously, the electrochemical cells and / or components of the electrochemical cells are essentially flat and / or disc-shaped.

[0055] In another variant, the electrochemical cell unit comprises a housing and / or a connection plate. The stack is enclosed by the housing and / or the connection plate.

[0056] The subsystem expediently comprises a subsystem housing and a subsystem connection plate. The subsystem connection plate, as a wall of the subsystem housing, preferably faces the electrochemical cell unit.

[0057] In a complementary variant, the oxidizing agent is air with oxygen or pure oxygen.

[0058] In a further embodiment, the at least one electrolysis cell unit is a PEM electrolysis cell unit and / or a SOFE high-temperature electrolyzer.

[0059] Preferably, the fuel cell unit is a PEM fuel cell unit with PEM fuel cells or an SOFC fuel cell unit with SOFC fuel cells or an alkaline fuel cell (AFC).

[0060] Short description of the drawings

[0061] In the following, exemplary embodiments of the invention are described in more detail with reference to the accompanying drawings. They show:

[0062] Fig. 1 is a highly simplified representation of a fuel cell system,

[0063] Fig. 2 is a highly simplified representation of an electrolysis cell system,

[0064] Fig. 3 shows a section through a centering device for a subsystem of an electrochemical cell unit in a first embodiment,

[0065] Fig. 4 shows a section through the centering device for the subsystem of the electrochemical cell unit in a second embodiment,

[0066] Fig. 5 shows a section through the centering device for the subsystem of the electrochemical cell unit in a third embodiment,

[0067] Fig. 6 is a section perpendicular to the plane of the drawing of Fig. 3, 4 or 5 and parallel to the circumferential direction only through the seal in a first embodiment, Fig. 7 is a section perpendicular to the plane of the drawing of Fig. 3, 4 or 5 and parallel to the circumferential direction only through the seal in a second embodiment,

[0068] Fig. 8 a section parallel to the circumferential direction only through the seal in a third embodiment and

[0069] Fig. 9 a side view of a fuel cell unit with subsystem.

[0070] Fig. 1 shows a fuel cell unit 1 as a fuel cell stack 3. The fuel cell unit 1 comprises the fuel cell stack 3 as an electrochemical cell stack 10, a housing 13 and a connection plate 15. The housing 13 defines an interior space 14. The connection plate 15 also functions as a housing 13 and is fixed to the remaining housing 13 by fixing elements 16, in particular screws 17. In the fuel cell stack 2, fuel cells 4 as PEM fuel cells 5 are stacked and arranged in alignment. Due to the large number of stacked fuel cells 4, approximately 300 to 400, not all of them are shown in Fig. 1 for the sake of simplicity. The principle of fuel cells 4 is that electrical energy or electrical current is generated by means of an electrochemical reaction.Hydrogen H2 is fed to an anode (not shown) as a gaseous recirculation fuel, and the anode forms the negative pole. A gaseous oxidant, namely air with oxygen, is fed to a cathode (not shown), i.e. the oxygen in the air provides the necessary gaseous oxidant. Reduction (electron absorption) takes place at the cathode. Oxidation (electron loss) takes place at the anode. The fuel cells 4 also comprise an ion exchange membrane as a proton exchange membrane (PEM), which is arranged between the anode and the cathode. On the two sides of the PEM, each facing the gas spaces, are the electrodes known as the anode and cathode (not shown). A unit comprising the PEM, anode, and cathode is referred to as a membrane electrode assembly (MEA) (not shown).A gas diffusion layer (GDL) is positioned on the anode and cathode. A bipolar plate (not shown) is positioned on top of the GDL. The electrically conductive bipolar plate serves as a current collector, for water drainage, and for conducting the reaction gases.

[0071] In the fuel cell unit 1, the fuel cells 4 are arranged between two clamping elements 18 as clamping plates 19. An upper clamping plate 20 rests on the uppermost fuel cell 4 and a lower clamping plate 21 rests on the lowermost fuel cell 4. The clamping elements 18 apply a compressive force to the fuel cells 4, i.e. the upper clamping plate 20 rests with a compressive force on the uppermost fuel cell 4 and the lower clamping plate 21 rests with a compressive force on the lowermost fuel cell 4. The fuel cell stack 3 is thus clamped in order to ensure the tightness for the fuel, the oxidizing agent and the coolant, in particular due to elastic seals, and also to keep the electrical contact resistance within the fuel cell stack 3 as low as possible.To clamp the fuel cells 4 with the clamping elements 18, four connecting devices 22 are designed as bolts 23 on the fuel cell unit 1, which are subjected to tensile stress. The four bolts 23 are firmly connected to the clamping plates 19.

[0072] An opening for introducing recirculation fuel into the recirculation fuel channels is formed in the connecting plate 15 and in the lower clamping plate 21. Furthermore, an opening for discharging recirculation fuel from the recirculation fuel channels is formed in the connecting plate 15 and in the lower clamping plate 21 as the clamping element 18. Further openings for introducing oxidizing agent and discharging oxidizing agent are formed in the connecting plate 15 and the lower clamping plate 21 as the clamping element 18, as well as openings (not shown) for introducing coolant and discharging coolant. Thus, a total of six openings are formed in the connecting plate 15 and the lower clamping plate 21 (only partially shown in Fig. 1).

[0073] A fuel cell system 2 comprises, in addition to the fuel cell unit 1, an oxidant supply system 26 for supplying the fuel cell stack 3 with air as the oxidant. The oxidant supply system 26 comprises a gas delivery device 27, for example a blower, a compressor, a turbo compressor driven by an electric motor and / or a turbine, and oxidant lines 28.

[0074] In addition to the fuel cell unit 1, the fuel cell system 2 also comprises a fuel supply system 29 for supplying the fuel cell stack 3 with hydrogen as fuel. The fuel supply system 29 comprises a pressure vessel 30, a fuel line 31 as a process fluid line, valves (not shown) for fuel, in particular an injector (not shown) for controlling the volume flow of fuel introduced from the fuel line 31 into the recirculation line 32, a heat exchanger (not shown) for fuel, a pressure reducer (not shown), a recirculation fuel line 32 as a process fluid line, a recirculation fuel feed device 33, an electric motor (not shown) for driving the recirculation fuel feed device 33, and a water separator 34 for separating water from the recirculation fuel.a water tank (not shown) for collecting the water collected in the water separator 34, a drain valve (not shown) for draining water from the water tank, and a drain valve as a purge valve (not shown) for discharging recirculation fuel into the environment. In the fuel supply system 29 for supplying the fuel cell stack 3 with hydrogen as fuel, the hydrogen stored in the pressure tank 30 at a high pressure of, for example, 400 bar is supplied to the fuel cells 4 through the fuel line 31. After the fuel has been passed through the fuel cells 4, the hydrogen is not completely consumed.So that this hydrogen derived from the fuel cells 4 is fed back to the fuel cells 4 in a circuit via the recirculation fuel line 32. The recirculation fuel conveying device 33 is used to convey the recirculation fuel through the recirculation fuel line 32. After the fuel passes through the fuel cells 4, the moisture content of the fuel increases, so that to prevent an excessive water or moisture content in the recirculation fuel, the fuel supply system 29 includes the water separator 34. The water separated in the water separator 34 is collected in the water tank (not shown) and discharged into the environment through the drain valve (not shown). Excess recirculation fuel is discharged into the environment through the purge valve (not shown).

[0075] In addition to the fuel cell unit 1, the fuel cell system 2 also comprises a cooling system (not shown) for controlling the temperature of the fuel cell stack 3, i.e., for cooling the fuel cell stack 3. The cooling system for controlling the temperature of the fuel cell stack 3 comprises coolant lines as process fluid lines, a heat exchanger, and a pump for circulating the coolant. The coolant is conducted through coolant channels in the bipolar plates of the fuel cells 4, and the heat is dissipated to the environment at the heat exchanger. In addition to the fuel cell unit 1, the fuel cell system 2 also comprises the oxidant supply system 26, the fuel supply system 29, and the cooling system (not shown) as a coolant supply system.

[0076] The fuel cell unit 1 can, with modifications not shown, in particular valves, also optionally be used and operated as an electrolysis cell unit 6, i.e. it forms a reversible fuel cell unit 1 or is designed to be operable only as an electrolysis cell unit 6. Some features are described below that enable the operation of the fuel cell unit 1 as an electrolysis cell unit 6. A liquid electrolyte, namely highly diluted sulfuric acid with a concentration of approximately c (H2SO4) = 1 mol / l, is used for the electrolysis. A sufficient concentration of oxonium ions H3C in the liquid electrolyte is necessary for the electrolysis. Fig. 2 shows an electrolysis cell unit 6 that can only be used for electrolysis.

[0077] The polarity of the electrodes with electrolysis when operated as an electrolysis cell unit 6 is the opposite (not shown) to when operated as a fuel cell unit 1, so that hydrogen H2 is formed at the cathodes in the channels for fuel, through which the liquid electrolyte is passed, and the hydrogen H2 is absorbed by the liquid electrolyte and transported along in dissolved form. Analogously, the liquid electrolyte is passed through the channels for oxidizing agents and oxygen O2 is formed at the anodes or at the channels for oxidizing agents. The fuel cells 2 of the fuel cell unit 1 function as electrolysis cells 9 when operated as an electrolysis cell unit 6. The fuel cells 2 and electrolysis cells 9 thus form electrochemical cells 24. The oxygen O2 formed is absorbed by the liquid electrolyte and transported along in dissolved form.The hydrogen H2 formed is absorbed by the liquid electrolyte and transported along in dissolved form. The liquid electrolyte is stored in a storage container 35 and is conveyed by a pump 37 and through electrolyte lines 36 through the channels in the electrolysis cell stack 8 or electrolysis cell stack 8 as an electrochemical cell stack 10. For a reversible fuel cell unit 1 (not shown) according to Fig. 1, two 3-way valves (not shown) are provided on the recirculation fuel line 32 and the oxidant line 28 and are switched over during operation as an electrolysis cell unit 6, so that not recirculation fuel and oxidant, but the liquid electrolyte is introduced by the pump 37 from the storage container 35 into the recirculation fuel line 32 and the oxidant line 28 as the electrolyte line 36.A hydrogen separator 38 separates the hydrogen obtained from electrolysis from the electrolyte. An oxygen separator 39 separates the oxygen obtained from electrolysis from the electrolyte. The electrolyte is circulated through the electrolysis cell unit 6, and sulfuric acid is added according to consumption using a device not shown. In addition to the electrolysis cell unit 6 with the electrolysis cell stack 8, the electrolysis cell system 6 also comprises an electrolyte supply system 12. The electrolyte supply system 12 comprises the storage tank 35, the electrolyte lines 36, and the pump 37, as well as the hydrogen separator 38 and the oxygen separator 39. A fuel cell unit 1 and an electrolysis cell unit 6 form an electrochemical cell unit 25. A fuel cell system 2 and an electrolysis cell system 7 form an electrochemical cell system 11.

[0078] The oxidant supply system 26, the fuel supply system 29 and the coolant supply system of the fuel cell system 2 each form a subsystem 40 for the fuel cell unit 1. Analogously, the electrolyte supply system 12 forms a subsystem 40 for the electrolysis cell unit 6. The subsystem 40 can also be designed as an electrical system for the electrochemical cell unit 25, for example with a battery and / or a transformer and / or an inverter.

[0079] The subsystem 40 is installed within a subsystem housing 41. The subsystem housing 41 also includes a subsystem connection plate 43, which faces the housing 13 of the electrochemical cell unit 25. The components of the subsystem 40 are arranged within a subsystem interior 42. The subsystem interior 42 is delimited by the subsystem housing 41. The subsystem connection plate 43, which faces the electrochemical cell stack 10 and the electrochemical cell unit 25, has an opening 59. The subsystem housing 41 is fastened to the housing 13, in particular the connection plate 15, in a form-fitting and / or force-fitting manner by a fastening device 46 as at least one subsystem fixing element 44. The at least one subsystem fixing element 44 is formed, for example, by a subsystem screw 45 and / or a subsystem bayonet connection.During assembly of the electrochemical cell system 11, the subsystem 40 with the subsystem housing 41 is moved in a direction of movement 56 as an axial direction 57 toward the housing 13. This movement of the subsystem 40 with the subsystem housing 41 toward the housing 13 of the electrochemical cell unit 25 is a relative movement, on the one hand, between the electrochemical cell unit 25 with the housing 13 and, on the other hand, the subsystem 40 with the subsystem housing 41. Thus, the electrochemical cell unit 25 with the housing 13 can also be moved toward the subsystem 40 with the subsystem housing 41, and the subsystem 40 is then attached and fixed to the electrochemical cell unit 25, in particular the housing 13, using the fastening device 46.

[0080] During assembly and movement of the subsystem 40 on the electrochemical cell unit 25, alignment and positioning of the subsystem 40 relative to the electrochemical cell unit 25 is necessary and this is carried out with a centering device 47. The centering device 47 comprises a contact component 48 with a contact geometry 50 and a

[0081] Counter contact component 49 with a counter contact geometry 51 (Fig. 3 to 5).

[0082] Fig. 3 shows a first exemplary embodiment of the centering device 47 and a seal 55. On the connection plate 15 of the housing 13 of the electrochemical cell unit 25, a recess 52 is formed completely around the circumference in a circumferential direction 58. A projection 53 is formed on the subsystem connection plate 43 of the subsystem housing 41. The projection 53 is formed completely around the circumference in the circumferential direction 58. The projection 53 forms the contact component 48. The recess 52 is formed on the housing 13, i.e. the connection plate 15, so that a partial region of the connection plate 15 at the recess 52 forms the mating contact component 49. The contact component 48 is thus formed in one piece on the subsystem housing 41, i.e. the subsystem connection plate 43. The counter contact component 49 is formed in one piece on the housing 13, ie the connection plate 15. In the housing 13, iethe connection plate 15, a groove 54 is formed and the seal 55 is partially arranged in the groove 54. The groove 54 and also the seal 55 are formed completely circumferentially with respect to the opening 59 of the subsystem housing 41. Due to the size of the opening 59, the flat subsystem connection plate 43 is essentially annular or circumferentially formed to delimit the opening 58. The seal 55 thus enables the opening 59 and the subsystem interior 42 to be sealed off from the environment. The seal 55 thus lies on the housing 13, i.e. the connection plate 15 and on the subsystem housing 41, i.e. the subsystem connection plate 43. The contact component 48 lies with the contact geometry 50 on the mating contact geometry 51 of the mating contact component 49 and the direct contact between the contact geometry 50 and the.

[0083] Mating contact geometry 51 is not shown in Fig. 3. The contact geometry 50 and the mating contact geometry 51 are designed as a substantially flat surface and are aligned substantially parallel to the direction of movement 56 during assembly. During assembly and fastening of the subsystem 41 to the housing 13 of the electrochemical cell unit 25, the contact geometry 50, which is designed entirely in the circumferential direction 58, is thus placed on the mating contact geometry 51, which is designed entirely in the circumferential direction 58, and moved in the further direction of movement to enlarge the contact area between the contact geometry 50 and the mating contact geometry 51 until the subsystem housing 41 rests on the elastic seal 55, for example made of rubber, on the subsystem connection plate 53.Subsequently, the subsystem 40 is fastened to the housing 13 of the electrochemical cell unit 25 using the fastening device 46, so that the elastic seal 55 is elastically preloaded with a compressive force between the connection plate 15 and the subsystem connection plate 43. The seal 55 is an axial seal 55 because the preload of the seal 55 is present in the axial direction 57 with the compressive force.

[0084] Fig. 4 shows a second exemplary embodiment of the centering device 47. In the following, essentially only the differences from the first exemplary embodiment according to Fig. 3 are described. The groove 54 for receiving the seal 55 is formed on the projection 53 as the contact component 48 on the subsystem connection plate 43 of the subsystem housing 41. The seal 55 rests directly on the mating contact geometry 51 of the mating contact component 49. The seal 55 is thus arranged, in particular in a direction perpendicular to the circumferential direction 58, between the contact geometry 50 and the mating contact geometry 51. The seal 55 is arranged, in particular completely, between the contact component 48 and the mating contact component 49. The seal 55 is a radial direction 55 because the preload and the application of the compressive force to the seal 55 is present in a radial direction 60 perpendicular to the axial direction 57.There is a direct contact between the contact geometry 50 and the mating contact geometry 51, which is not shown for graphic reasons. The contact component 48 can be formed additionally and / or alternatively by the seal 55, so that the contact geometry 50 is formed by the area of ​​the outer side of the seal 55 facing the mating contact component 49.

[0085] Fig. 5 shows a third exemplary embodiment of the centering device 47. In the following, essentially only the differences from the first exemplary embodiment according to Fig. 3 are described. The groove 54 for receiving the seal 55 is formed on the subsystem housing 41 as the subsystem connection plate 43. The recess 52 is formed on the subsystem housing 41, i.e., the subsystem connection plate 43. A partial region of the subsystem housing 41 thus forms the mating contact component 49 with the mating contact geometry 51. The projection 53 is formed on the housing 13, i.e., on the connection plate 15, of the electrochemical cell unit 25, so that the contact component 48 is formed integrally on the housing 13. A partial region of the housing 13 at the projection 53 thus forms the contact component 48 with the contact geometry 50.The contact geometry 50 and the mating contact geometry 51 are flat and aligned at an acute angle of approximately 45° to the axial direction 57. The contact geometry 50 and the mating contact geometry 51 are thus aligned conically with respect to the axial direction 57. During assembly and movement of the subsystem 40 with the subsystem housing 41 in the direction of movement 56 to the housing 13, the

[0086] Contact geometry 50 and mating contact geometry 51, due to their conical shape, facilitate the movement of subsystem 40 toward electrochemical cell unit 25. There is direct contact between contact geometry 50 and mating contact geometry 51, which is not shown for illustrative reasons. In this case, contact component 48 can be formed additionally and / or alternatively by seal 55, so that mating contact geometry 51 is formed by the region of the outer side of seal 55 facing contact component 48.

[0087] Fig. 6 shows a section through the seal 55 perpendicular to the sectional planes of Figs. 3 to 5 in a first exemplary embodiment. The seal 55, which is formed as a closed ring completely in the circumferential direction 58 with a circumferential angle a of 360°, is circular in shape. Due to this geometry of the seal 55, the contact component 48 and the counter-contact component 49 are also circular in shape.

[0088] Fig. 7 shows a section through the seal 55 perpendicular to the sectional planes of Figs. 3 to 5 in a second exemplary embodiment. The seal 55, which is formed entirely in the circumferential direction 58 with a circumferential angle a of 360°, is rectangular. Due to this geometry of the seal 55, the contact component 48 and the counter-contact component 49 are also rectangular.

[0089] Fig. 8 shows a section through the seal 55 parallel to the circumferential direction 58 in a third exemplary embodiment. The seal 55, which is partially formed in the circumferential direction 58 with a circumferential angle a of 90°, is L-shaped. Due to this geometry of the seal 55, the contact component 48 and the counter-contact component 49 are also partially formed in the circumferential direction 58 with a circumferential angle a of 90° and are L-shaped.

[0090] Overall, the electrochemical cell system 11 according to the invention offers significant advantages. The centering device 47, formed by the contact component 48 and the mating contact component 49, not only serves to align and position the subsystem 40 relative to the electrochemical cell unit 25, but also functions to arrange the seal 55. The contact geometry 50 and the mating contact geometry 51 are to be machined and manufactured due to the necessary high manufacturing accuracies. The seal 55 is arranged on and / or near the contact geometry 50 and / or the mating contact geometry 51, such that the machining and manufacture of the contact geometry 50 and the mating contact geometry 51 can be used in one machining step with one tool in order to machine and manufacture the entire contact surface of the seal 55 in this machining step.This can advantageously reduce costs.

Claims

Claims 1 . Electrochemical cell system (11) with an electrochemical cell unit (25) for converting electrochemical energy into electrical energy as a fuel cell unit (1) and / or for converting electrical energy into electrochemical energy as an electrolysis cell unit (6), comprising - stacked electrochemical cells (24) as a cell stack (10), - a housing (13) for the cell stack (24) and the cell stack (24) is arranged within the housing (13), - a subsystem (40) for the cell stack (24), - a fastening device (46) for fastening the subsystem (40) to the housing (13) of the cell stack (24) and the subsystem (40) is fastened to the housing (13) with the fastening device (46), characterized in that the electrochemical cell unit (24) comprises a centering device (47) with a contact geometry (50) and a counter-contact geometry (51) for positioning the subsystem (40) relative to the housing (13) for the cell stack (10).

2. Electrochemical cell system according to claim 1, characterized in that the contact geometry (50) is formed on a contact component (48) and the counter-contact geometry (51) is formed on a counter-contact component (49), so that the centering device (47) is formed by the contact component (48) and the counter-contact component (49).

3. Electrochemical cell system according to claim 2, characterized in that the contact geometry (50) is formed on a recess (52) of the contact component (48) and / or the counter-contact geometry (51) is formed on a projection (53) of the counter-contact component (49).

4. Electrochemical cell system according to claim 2 or 3, characterized in that the contact geometry (50) is formed on a projection (53) of the contact component (48) and / or the counter-contact geometry (51) is formed on a recess (52) of the counter-contact component (49).

5. Electrochemical cell system according to claim 3 or 4, characterized in that the recess (52) is formed completely circumferentially, in particular annularly, on the contact component (48).

6. Electrochemical cell system according to claim 4 or 5, characterized in that the projection (53) is formed completely circumferentially, in particular annularly, on the counter-contact component (51).

7. Electrochemical cell system according to one or more of claims 2 to 6, characterized in that the contact component (48) is formed at least partially, in particular completely, in one piece with the housing (13) for the cell stack (10) and / or the counter-contact component (49) is formed at least partially, in particular completely, in one piece with a subsystem housing (41).

8. Electrochemical cell system according to one or more of claims 2 to 7, characterized in that the contact component (48) is formed at least partially, in particular completely, in one piece with the subsystem housing (41) and / or the counter-contact component (51) is formed at least partially, in particular completely, in one piece with the housing (13) for the cell stack (10).

9. Electrochemical cell system according to one or more of claims 2 to 8, characterized in that the contact component (48) on the contact geometry (50) and the counter-contact component (49) on the counter-contact geometry (51) lie on one another.

10. Electrochemical cell system according to one or more of the preceding claims, characterized in that the contact geometry (50) and the counter-contact geometry (51) are substantially parallel to a direction of movement (56) of the subsystem (40) during assembly and fastening of the subsystem (40) to the Housing (13) are aligned as axial direction (57).

11. Electrochemical cell system according to one or more of the preceding claims, characterized in that the contact geometry (48) and the counter-contact geometry (49) are aligned at an acute angle to a direction of movement (56) of the subsystem (40) during assembly and fastening of the subsystem (40) to the housing (13) as an axial direction (57), so that the contact geometry (50) and the counter-contact geometry (51) are conical.

12. Electrochemical cell system according to one or more of the preceding claims, characterized in that the contact geometry (50) and the counter-contact geometry (51) are complementary to one another, in particular planar.

13. Electrochemical cell system according to one or more of claims 2 to 12, characterized in that a seal (55) is formed between the contact component (48) and the counter-contact component (49), in particular between the contact geometry (50) and the counter-contact geometry (51).

14. Electrochemical cell system according to claim 13, characterized in that the seal (55) is completely circumferential, in particular annular, is trained.

15. Electrochemical cell unit according to one or more of the preceding claims, characterized in that the contact geometry (50) and the counter-contact geometry (51) are formed in the circumferential direction (58) with a circumferential angle (α) of at least 30° or 90°, in particular completely circumferentially with a circumferential angle of 360°.

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