Energy converter system, vehicle and method for manufacturing an energy converter system

Abstract

The present invention relates to an energy converter system (10) comprising a stacking housing (11), a stacking volume formed in the stacking housing (11), a stacking structure (12) arranged in the stacking volume for electrochemical energy conversion, a compensating housing (14) outside the stacking housing (11), a compensating volume formed in the compensating housing (14), a connecting line (16) with a line volume (17) for a fluid connection between a stacking fluid volume (13) within the stacking volume and a compensating fluid volume (15) within the compensating volume, wherein the stacking fluid volume (13), the compensating fluid volume (15) and the line volume (17) form a total fluid volume (18), a fluid (35) in the total fluid volume (18) for pressurizing the stacking structure (12), and a mechanical spring unit (19) arranged in the compensating volume for pressure compensation in the total fluid volume (18). in the case of a change in the length of the stack structure (12).The invention further relates to a vehicle (100) with an energy converter system (10) according to the invention and to a method for manufacturing an energy converter system (10) according to the invention.

Description

[0001] The technology disclosed here relates to an energy converter system, in particular for a vehicle, a method for producing an energy converter system and a vehicle with the energy converter system.

[0002] Energy conversion systems such as fuel cell systems typically comprise multiple fuel cells arranged in a fuel cell stack. To compensate for a change in the length of the fuel cell stack, it is typically stored under pressure. For this purpose, it is known to provide a compensation device for a fuel cell system that comprises a gas-filled and pressurized compensation bellows on a fuel cell stack and a compensation tank that is thermally insulated from and spaced from the fuel cell stack and coupled to the compensation bellows via a connecting line. Gas pressure or overpressure generated in the compensation tank can be transferred to the compensation bellows via the connecting line, thereby achieving the desired compensation for the linear expansion.

[0003] The object of the technology disclosed here is to improve known systems for compensating for linear expansion in a fuel cell system. The above object is achieved by the patent claims. In particular, the above object is achieved by the energy converter system according to claim 1 and the vehicle and the method according to the independent claims. Further advantages of the invention emerge from the dependent claims, the description, and the figures. Features described in connection with the energy converter system naturally also apply in connection with the vehicle according to the invention, the method according to the invention, and vice versa, so that with regard to the disclosure, reciprocal reference is and / or can always be made to the individual aspects of the invention.

[0004] According to a first aspect, an energy converter system is proposed, comprising: - a stackable housing, - a stacking volume formed in the stacking housing, - a stack structure arranged in the stack volume for electrochemical energy conversion, - a compensation housing outside the stack housing, - a compensation volume formed in the compensation housing, - a connecting line with a line volume for a fluid connection between a stack fluid volume within the stack volume and a compensating fluid volume within the compensating volume, wherein the stack fluid volume, the compensating fluid volume and the line volume form a total fluid volume, - a fluid in the total fluid volume for pressurizing the stack structure, and - a mechanical spring unit arranged in the compensation volume for pressure compensation in the total fluid volume in the event of a change in the length of the stack structure.

[0005] The present invention is initially based on the approach of relocating the means for pressure compensation of the length change of the stack structure, which were previously installed in the stack housing, from the stack housing. Subsequently, the available installation space or the compensation volume in the relocated compensation housing was utilized in such a way that not only the compensation fluid volume is configured there, but also a mechanical spring unit is positioned in a further compensation sub-volume. The mechanical spring unit, in combination with the compensation fluid volume and the fluid introduced there or the fluid in the total fluid volume, can create a simple yet reliably functioning fluid pressure compensation for length changes of the stack structure during operation of the energy converter system. At the same time, the design of the stack housing and the functional units previously positioned there can be simplified.

[0006] The compensation volume can be understood as a total compensation volume comprising the compensation fluid volume and at least one further compensation partial volume for accommodating the mechanical spring unit. The compensation fluid volume and the compensation partial volume are preferably designed to be fluid-tight or substantially fluid-tightly separated from one another. Analogously, the stack volume can be understood as a total stack volume comprising the stack fluid volume and at least one further stack partial volume for accommodating the stack structure. The stack fluid volume and the stack partial volume are likewise preferably designed to be fluid-tight or substantially fluid-tightly separated from one another. The mechanical spring unit can, for example, have a helical compression spring or a disc spring or be designed as a corresponding spring.

[0007] The energy converter system can be understood to mean a fuel cell system or a subsystem of a fuel cell system. The technology disclosed here therefore preferably relates to a fuel cell system with at least one fuel cell. The fuel cell system is intended, for example, for mobile applications such as motor vehicles, in particular for providing energy for at least one drive machine such as an electric motor for propulsion of the motor vehicle. In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, thereby producing electricity and heat. The fuel cell comprises an anode and a cathode separated from each other by an ion-selective or ion-permeable separator. The anode is supplied with fuel. The cathode is supplied with oxidant. The stack structure can have at least one fuel cell.Preferably, the stack structure comprises a plurality of fuel cells forming a fuel cell stack.

[0008] The desired fluid pressure in the total fluid volume can be introduced into the line volume or generated in the line volume via a fluid inlet, for example a valve arrangement on the connecting line, whereby the fluid can also be introduced into the total fluid volume at another point in the energy conversion system. In this case, a fluid can be understood to be a liquid or a gas. The fluid for building up the fluid pressure can be, for example, air and / or nitrogen. The fluid can be used or provided for the direct or indirect pressurization of the stack structure. The fluid can exert the pressurization directly on the stack structure as a liquid. Alternatively, the fluid can exert the pressurization indirectly on the stack structure in gaseous form and, for example, by means of a bellows in which the fluid can be located.Regardless of the fluid, the pressure applied to the stack structure can be applied directly or via additional intermediate elements such as a separate pressure plate.

[0009] The change in length can be understood as a longitudinal expansion of the stack structure in a longitudinal direction of the stack structure. In the case of a fuel cell stack with a plurality of fuel cells arranged in a stack, the longitudinal direction can correspond to a stacking direction. Two end plates can be positioned on the two end faces of the stack structure. More precisely, a first end plate can be positioned on a first end face and a second end plate on a second end face. The first end plate can be understood as a plate-shaped pressure element and / or pressure plate that is configured to pressurize the stack structure using the fluid pressure in the stack fluid volume. For this purpose, the first end plate can be positioned displaceably and / or movably in the stack volume by means of different fluid pressures and / or changes in the length of the stack structure.The second end plate can be designed as part of the stack housing and consequently at least substantially outside the stack volume and fixed locally.

[0010] According to a further embodiment, it is possible for the total fluid volume in an energy conversion system to be designed as a closed system for the operation of the energy conversion system, i.e. at the latest during operation of the energy conversion system. In this way, the energy conversion system can be designed to be relatively simple and compact. Furthermore, with the total fluid volume as a closed system, a relatively robust operation of the energy conversion system can be achieved. In the case of a closed system, no or essentially no fluid exchange takes place with the environment of the total fluid volume and / or with a volume outside the total fluid volume during operation of the energy conversion system. The spring unit can therefore be considered part of a closed mechanical spring assembly. The connecting line can be understood as a tubular and / or hose-shaped connecting line.The connecting line preferably establishes the desired fluid connection exclusively between the compensating fluid volume and the stack fluid volume.

[0011] Furthermore, an energy conversion system according to the present technology can comprise a tensioning force means arranged in the differential housing, which can be actuated to increase and decrease the tensioning force of the spring unit, and an adjustment means arranged outside the differential housing for actuating the tensioning force means. The adjustment means arranged outside the differential housing allows the spring unit and the total fluid volume to be provided as a closed system, while still allowing the tensioning force to be easily adjusted to the desired value. The tensioning force means can be understood as a plate-shaped element via which the mechanical spring unit can be compressed more or less, thereby changing the tensioning force or preload force of the spring unit accordingly.Changing the clamping force can be carried out in particular after the total fluid volume has been filled with fluid and / or during a service appointment. Increasing and decreasing the clamping force can be understood as setting, controlling, regulating, changing and / or adjusting the clamping force. If, for example, a gas is used as the fluid, increasing the clamping force can increase the gas pressure, which in turn can increase the pressure on the stack structure. The fact that the adjusting means is arranged outside the differential housing can be understood to mean that at least part of the adjusting means is arranged and / or configured outside the differential housing, wherein another part of the adjusting means can be positioned inside the differential housing for transmitting force to the clamping force means.

[0012] In the proposed energy converter system, it is further possible for the adjustment means to be configured for manual actuation of the tensioning force means. In this way, the pressure compensation can be modified and / or adjusted particularly easily. To enable manual actuation, the adjustment means can have a handle that is operatively connected to the tensioning force means. The tensioning force means and / or the adjustment means can be screwed to the compensation housing, so that the tensioning force means can be actuated, in particular pressed linearly against the spring unit, by a screwing movement of at least part of the tensioning force means and / or at least part of the adjustment means.

[0013] Furthermore, the energy converter system described here can comprise an actuator for the adjustment means, one or at least one gas pressure sensor for determining a gas pressure value in the total fluid volume, and a control unit for automatically controlling the actuator to actuate the clamping force means based on the determined gas pressure value. In this way, the actuation of the clamping force means can be automated in a simple and space-saving manner. The actuator can be understood as an electrically controllable actuating means that takes over the otherwise manual actuation of the clamping force means by converting electrical signals from the control unit into a mechanical movement of the adjustment means. The gas pressure sensor is preferably configured to determine a gas pressure in the line volume. For this purpose, the gas pressure sensor or a part of the gas pressure sensor can be positioned on the connecting line. The control unit can be designed as a computer or part of a computer.The control unit can be configured as an engine control unit (ECU) or as part of such an ECU. For example, the control unit for a fuel cell system can also be configured and / or provided as a so-called stack management unit. The control unit of the present technology can be viewed as a standalone control unit in addition to a main control unit of a vehicle with the energy conversion system or as part of the main control unit. The gas pressure sensor is preferably in direct signal communication with the control unit so that the gas pressure values ​​determined by the gas pressure sensor can be transmitted to the control unit with the shortest possible delay. The control unit can then control the actuator based on the received gas pressure values. However, additional parameters, operating states, and / or measured values ​​can also be taken into account for automated control of the actuator.Thus, in addition to or as an alternative to the gas pressure sensor, the energy converter system can have at least one tension force sensor for determining a tension or compressive force on the stack structure and / or for determining a tension force of the spring unit. The tension force sensor can be connected to the control unit via a signal, similar to the gas pressure sensor. Automatic control can also be understood as automated and / or autonomous control.

[0014] In an energy conversion system, it is also possible for the fluid to be a gas and for the gas pressure in the total fluid volume to be set to a value in a range between 7 bar and 11 bar. Tests conducted within the scope of the present invention have shown that efficient yet safe operation of the energy conversion system, and in particular of the stack structure in the form of a fuel cell stack, can be achieved with gas pressures in this range. Additionally or alternatively, it has proven equally advantageous if the pressurization of the stack structure is configured with a clamping force in a range between 30 kN and 50 kN.

[0015] Furthermore, in an energy converter system according to the present technology, it is possible for a stack bellows to be positioned in the stack fluid volume for pressurizing a first end plate of the stack structure and / or for a compensating bellows to be positioned in the compensating fluid volume for pressurizing the spring unit. In this case, the fluid is understood to be a gas that can implement the desired pressurization in a controlled manner by means of the stack bellows and / or the compensating bellows. The stack bellows and / or the compensating bellows can be provided as rubber bellows. The stack bellows is preferably positioned on a media-remote side of the stack structure or of a corresponding fuel cell stack. The compensating bellows can be understood as the master bellows, and the stack bellows can be understood as the slave bellows.Consequently, the compensating bellows can be configured such that, by means of the spring unit, it specifies the pressure on the stacking bellows or the pressure generated by the stacking bellows on the stack structure. The pressurization of the spring unit by the compensating bellows can also be understood as the pressurization of the compensating bellows by the spring unit. The gas-filled compensating bellows can therefore be understood as a counterpressure medium for the spring unit. Accordingly, the gas-filled stacking bellows can be understood as a counterpressure medium for the stacking structure, especially when the stacking structure experiences a positive change in length in the longitudinal direction.

[0016] An energy converter system according to the present technology can further comprise a cartridge-like gas outlet means positioned in and / or on the total fluid volume for introducing gas into the total fluid volume. In this case, a fluid inlet for introducing the required fluid from outside the total fluid volume via a conduit system can be omitted. The total fluid volume can thus be designed to be particularly compact and, in particular, fluid-tight. The cartridge-like gas outlet means can comprise an activation means for contactless activation of a gas outlet process. For this purpose, the activation means can comprise, for example, a timer means, a radio means, and / or another means for contactless activation of the gas outlet means from outside the total fluid volume.

[0017] A further aspect of the present invention relates to a vehicle having an energy converter system as described above and at least one electric motor for driving the vehicle, wherein the energy converter system is configured to supply power to the at least one electric motor. The vehicle thus offers the same advantages as have been described in detail with reference to the energy converter system. The vehicle can be understood to mean a motor vehicle such as a motor-driven two-wheeler, a car, or a truck. The vehicle can also be understood to mean a road vehicle, an aircraft, a watercraft, a rail vehicle, a spacecraft, or a robot. The vehicle can also be understood to mean a purely electric vehicle or a hybrid electric vehicle, which, in addition to the at least one electric motor, has an internal combustion engine for propulsion.

[0018] Furthermore, one aspect of the present technology relates to a method for manufacturing an energy conversion system as described above. The method comprises the following steps: - Positioning the spring unit in the compensation volume, - Positioning the stack structure in the stack volume, - mechanical fixing of the stack structure in the stack volume and / or on the stack housing and then - Introducing the fluid into the total fluid volume to pressurize the stack structure.

[0019] The method according to the invention therefore also offers the advantages described above with reference to the energy conversion system. If the energy conversion system is manufactured as a fuel cell system and the stack structure comprises a fuel cell stack with several fuel cells, the fuel cells can first be stacked. The finished fuel cell stack can then be mechanically secured in the stack volume. The stack bellows described above can then be inflated or filled with gas until the desired gas pressure in the total fluid volume is reached. More complicated fastening of the stack structure after pressure has built up can be dispensed with. The fluid can be introduced until the compression and / or tightness required for the operation and / or function of the energy conversion system is achieved and, if necessary, can be adjusted via the adjustable preload of the spring unit.can be adjusted until the energy conversion system has been manufactured to be operational and / or ready for use. A simultaneous and / or immediately following leak test can be performed, during which the spring unit can be fine-tuned if necessary to account for manufacturing and / or assembly tolerances or different settling behavior, particularly during initial clamping of the stack structure.

[0020] Further measures improving the invention will become apparent from the following description of various exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages apparent from the claims, the description, or the figures, including structural details and spatial arrangements, may be essential to the invention both individually and in various combinations.

[0021] They show schematically: Fig. 1 an energy converter system according to a first embodiment of the present technology, Fig. 2 a vehicle according to a first embodiment of the present technology, Fig. 3 an energy converter system according to a second embodiment of the present technology, Fig. 4 an energy converter system according to a third embodiment of the present technology, and Fig. 5 is a flowchart for explaining a method of manufacturing an energy conversion system according to the present technology.

[0022] Elements with the same function and mode of operation are provided with the same reference symbols in the figures.

[0023] Fig. 1 shows an energy conversion system 10 according to a first embodiment. The energy conversion system 10 shown is depicted in the form of a fuel cell system. The energy conversion system 10 comprises a stack housing 11, a stack volume formed in the stack housing 11, and a stack structure 12 arranged in the stack volume for electrochemical energy conversion. The stack structure 12 is provided in the form of a fuel cell stack. The stack housing 11 has a first end plate 26 and a second end plate 27, each of which can also be considered part of the stack structure 12.

[0024] The energy converter system 10 further comprises a compensating housing 14 outside the stack housing 11, a compensating volume formed in the compensating housing 14, and a connecting line 16 with a line volume 17 for a fluid connection between a stack fluid volume 13 within the stack volume and a compensating fluid volume 15 within the compensating volume. The stack fluid volume 13, the compensating fluid volume 15, and the line volume 17 form a total fluid volume 18 in which a fluid 35 is located.

[0025] In the example shown, the fluid 35 is a gas under a pressure of approximately 9 bar, which correspondingly pressurizes the stack structure 12. More precisely, a stack bellows 34 for pressurizing a first end plate 26 of the stack structure 12 is located in the stack fluid volume 13, and a compensating bellows 33 is located in the compensating fluid volume 15. A mechanical spring unit 19 is configured in the compensating volume to compensate for pressure in the total fluid volume 18 in the event of a change in length of the stack structure 12. In the example shown, the spring unit 19 comprises a spiral spring provided as a compression spring 25. The compensating bellows 33 is configured to pressurize the spring unit 19, wherein the compensating bellows 33 is also interactively pressurized by the spring unit 19.In the example shown, the total fluid volume 18 for the operation of the energy converter system 10 is designed as a closed system in which, after the introduction of the fluid 35 through a fluid inlet 31 into the total fluid volume 18, no more fluid exchange takes place or should take place with an environment of the total fluid volume 18.

[0026] In the Fig. 1, the energy converter system 10 has a tensioning force means 20 arranged in the compensation housing 14, which can be actuated to increase and decrease the tensioning force of the spring unit 19. In addition, the energy converter system 10 has an adjusting means 21 arranged outside the compensation housing 14 for actuating the tensioning force means 20. In addition, the Fig. The energy converter system 10 shown in Figure 1 comprises an actuator 22 for actuating the adjustment means 21, a gas pressure sensor 23 for determining a gas pressure value in the total fluid volume 18, and a control unit 24 for automatically controlling the actuator 22 to actuate the clamping force means 20 based on the determined gas pressure value. To transmit the required measurement and control signals, the control unit 24 is in suitable signal communication with the actuator 22 and the gas pressure sensor 23. Fig. Figure 1 shows a wired signal connection. However, the signal connection can also be implemented as a wireless signal connection. In this case, the control unit 24, the actuator 22, and the gas pressure sensor 23 would have corresponding transmitters / receivers for wireless signal transmission.

[0027] In Fig. 2 shows a vehicle 100 with an energy conversion system 10 as described above. The vehicle 100 also has two electric motors 40, which are positioned in the area of ​​the front axle and in the area of ​​the rear axle of the vehicle 100 as drive motors of the vehicle 100. In the example shown, the energy conversion system 10 is configured to supply power to the two electric motors 40 and is electrically connected to the electric motors accordingly.

[0028] In Fig. 3 shows an energy converter system 10 according to a second embodiment. Fig. 3, the adjustment means 21 is configured for manually actuating the tensioning force means 20. On the Fig. The gas pressure sensor 23 shown in Figure 1, the control unit 24, and the actuator 22 can be omitted accordingly. Nevertheless, an embodiment would be possible in which both manual and automatic actuation are implemented.

[0029] In Fig. 4 shows an energy converter system 10 according to a third embodiment. Fig. In the energy converter system 10 shown in Figure 4, in addition to the gas pressure sensor 23, a spring force sensor 29 for determining the spring force of the spring unit 19 and a compression force sensor 30 for determining the clamping force on the stack structure 12 are provided. The spring force sensor 29 and the compression force sensor 30 are each in signal connection with the control unit 24, so that the latter can automatically control the actuator 22 for actuating the clamping force means 20 not only based on the determined gas pressure values, but also based on the determined spring force values ​​and / or clamping force values. As already described above, the control unit can be in wired or wireless signal connection with the various sensors and the actuator for transmitting the respective measurement and / or control signals. In addition, the Fig. 4, the energy converter system 10 has a cartridge-like gas outlet means 28 positioned in the line volume 17 for introducing gas into the line volume 17. The gas outlet means 28 can also be positioned at a different location in the total fluid volume 18. Fig. The fluid inlet 31 shown in Figure 1 can be omitted in this case.

[0030] With reference to Fig.5 explains important steps of a method for producing an energy converter system 10 as described above. In a first step S1, the spring unit 19 is first positioned in the compensation volume. In a second step S2, the stack structure 12 is positioned in the stack volume. Steps S1 and S2 can also be carried out in different orders or simultaneously. Subsequently, the stack structure 12 is mechanically fixed to the stack housing 11 and in the stack volume. The fluid 35 is then introduced into the total fluid volume 18 to pressurize the stack structure 12. Once the desired fluid pressure in the total fluid volume 18 and / or the desired pressurization or the corresponding clamping force on the stack housing 11 has been reached, the introduction of the fluid 35 is terminated.

[0031] The invention allows for further design principles in addition to the embodiments illustrated. This means that the invention should not be considered limited to the embodiments explained with reference to the figures. List of reference symbols 10 Energy converter system 11 stackable housings 12 Stack structure 13 Stack fluid volume 14 differential housing 15 Compensation fluid volume 16 connecting line 17 line volume 18 Total fluid volume 19 Spring unit 20 tensioning agents 21 Adjustment tools 22 Actuator 23 Gas pressure sensor 24 Control unit 25 compression spring 26 first end plate 27 second end plate 28 Gas outlet devices 29 Spring force sensor 30 Compression force sensor 31 Fluid inlet 33 Compensating bellows 34 Stacking bellows 35 Fluid 40 electric motor 100 vehicles

Claims

[1] Energy converter system (10), comprising: - a stacking housing (11), - a stacking volume formed in the stacking housing (11), - a stack structure (12) arranged in the stack volume for electrochemical energy conversion, - a compensation housing (14) outside the stack housing (11), - a compensation volume formed in the compensation housing (14), - a connecting line (16) with a line volume (17) for a fluid connection between a stack fluid volume (13) within the stack volume and a compensating fluid volume (15) within the compensating volume, wherein the stack fluid volume (13), the compensating fluid volume (15) and the line volume (17) form a total fluid volume (18), - a fluid (35) in the total fluid volume (18) for pressurizing the stack structure (12), and - a mechanical spring unit (19) arranged in the compensation volume for pressure compensation in the total fluid volume (18) in the event of a change in length of the stack structure (12). [2] Energy converter system (10) according to claim 1, characterized by that the total fluid volume (18) for the operation of the energy converter system (10) is designed as a closed system. [3] Energy converter system (10) according to one of the preceding claims, characterized by a tensioning force means (20) arranged in the differential housing (14) which can be actuated to increase and decrease the tensioning force of the spring unit (19) and an adjusting means (21) arranged outside the differential housing (14) for actuating the tensioning force means (20). [4] Energy converter system (10) according to claim 3, characterized by that the adjusting means (21) is configured for manually actuating the clamping force means (20). [5] Energy converter system (10) according to one of claims 3 to 4, characterized byan actuator (22) for the adjustment means (21), a gas pressure sensor (23) for determining a gas pressure value in the total fluid volume (18) and a control unit (24) for automatically controlling the actuator (22) to actuate the clamping force means (20) based on the determined gas pressure value. [6] Energy converter system (10) according to one of the preceding claims, characterized by that the fluid (35) is a gas and the gas pressure in the total fluid volume (18) is set to a value in a range between 7 bar and 11 bar. [7] Energy converter system (10) according to one of the preceding claims, characterized by that a stack bellows (34) is positioned in the stack fluid volume (13) for pressurizing a first end plate (26) of the stack structure (12) and / or a compensating bellows (33) is positioned in the compensating fluid volume (15) for pressurizing the spring unit (19). [8] Energy converter system (10) according to one of the preceding claims, characterized by a cartridge-like gas outlet means (28) positioned in and / or on the total fluid volume (18) for introducing gas into the total fluid volume (18). [9] Vehicle (100) comprising an energy converter system (10) according to one of the preceding claims and at least one electric motor (40) for driving the vehicle (100), wherein the energy converter system (10) is configured to supply power to the at least one electric motor (40). [10] Method for producing an energy converter system (10) according to one of claims 1 to 8, characterized by : - Positioning the spring unit (19) in the compensation volume, - Positioning the stack structure (12) in the stack volume, - mechanically fixing the stack structure (12) in the stack volume and / or on the stack housing (11) and then - Introducing the fluid into the total fluid volume (18) to pressurize the stack structure (12).

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