Tank system and method for operating a tank system

Abstract

The invention relates to a method (100) for operating a tank system (305) comprising a plurality of tanks (307). The method (100) has the steps of: - determining (101) an individual temperature in each tank (307) of the plurality of tanks (307), - determining (103) the individual fill level of each tank (307) of the plurality of tanks (307) on the basis of the individual temperature, - opening (105) the tanks (307) of the plurality of tanks (307) having the highest fill levels, and - opening (107) a number of other tanks (307) of the plurality of tanks (307) as soon as the fill level of the opened tanks (307) reaches the fill level of the other tanks (307).

Description

[0001] Description

[0002] title and methods for operating a

[0003] The presented invention relates to a method for operating a tank system, a tank system and a transport system according to the attached claims.

[0004] State of the art

[0005] To power mobile applications with hydrogen, these applications must be able to carry the hydrogen with them. For this purpose, the hydrogen is usually stored in tank systems with more than one tank, both to allow for flexible and space-saving placement of the individual tanks, for example in a vehicle, and to maximize the vehicle's range.

[0006] Therefore, it is common for commercial vehicles, especially ships, trains, etc., to often have more than two tanks installed.

[0007] In a hydrogen storage system, a hydrogen storage control unit (HSCU) is used to provide all the necessary functions for operating the system. A key task is to control the hydrogen tank valves (HTV) so that they open and close at the correct time to ensure the proper functioning of the equipment.

[0008] Refueling or withdrawing hydrogen from a tank system can lead to different gas temperatures within the tanks. This can be caused, for example, by different tank sizes, varying environmental conditions (including sunlight, ambient temperature, and airflow), or throttling effects in the lines during refueling or withdrawal.

[0009] During subsequent periods of inactivity with the high-pressure valves closed, for example when the vehicle is parked or driven using battery storage, the temperature differences equalize, resulting in varying pressure levels in the tanks. This is disadvantageous because when the high-pressure tank valves are next opened, hydrogen equalization flows occur between the tanks. Due to the design of the high-pressure valves (HTV) on the tanks and their shared high-pressure line (rail), this can lead to an unintended refilling of individual tanks.

[0010] The integrated non-return valves in the HTV are designed to ensure that all tanks are at approximately the same static pressure level when the high-pressure valves are activated and during refueling.

[0011] Disclosure of the invention

[0012] Within the scope of the presented invention, a tank system, a method for operating the tank system, and a transport system are introduced. Further features and details of the invention will become apparent from the respective dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the tank system and the transport system according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention is always, or can always be, mutually interdependent.

[0013] The invention presented here serves in particular to provide a safe tank system.

[0014] Thus, according to a first aspect of the presented invention, a method for operating a tank system comprising a plurality of tanks is presented. The presented method comprises determining an individual temperature in each tank of the plurality of tanks, determining an individual fill level of each tank of the plurality of tanks based on the individual temperature, opening tanks of the plurality of tanks whose fill level is highest, and opening a number of further tanks of the plurality of tanks as soon as the fill level of the opened tanks reaches a fill level of the further tanks.

[0015] The presented method is based on a tank system with a multitude of tanks, i.e., more than one tank.

[0016] To compensate for temperature-related pressure differences in various tanks during operation of the tank system or the vehicle, for example when a vehicle with a tank system is switched off, and to reduce any inequality in the state of charge (SoC) of the respective tanks caused by refilling, it is provided that initially, i.e., for example when the tank system is started, individual fill levels of each tank of the multitude of tanks are determined, so that the current fill level of each tank is available.

[0017] The individual fill levels are determined based on the individual temperature in each tank. This individual temperature can be measured, for example, using a tank-specific temperature sensor.

[0018] Formula (1) can be used, for example, to determine the fill level based on the temperature:

[0019] Once the individual fill levels are known, the tank with the highest fill level in the system is opened, meaning the tank valve of the tank with the highest fill level is activated. This fills a high-pressure line and supplies a consumer with fuel from the system. As the consumer operates, the pressures in the opened tanks drop, and their temperatures typically fall more quickly than in the still-closed tanks, thus equalizing the fill levels of all tanks in the system.

[0020] If the system is switched off during this operating phase, before all tanks have been opened but fuel has already been consumed, the difference in the fill level of the various tanks will have decreased, at least partially. Therefore, after the tanks have cooled down over a longer period of inactivity, a smaller pressure difference between them can be expected.

[0021] Once the tank with the highest fill level of all tanks in the system is opened, the next highest fill level is opened. A further tank is opened as soon as the fill level of the opened tanks reaches the level of the remaining tanks.

[0022] It may be provided that the opening of the number of additional tanks is repeated until all tanks of the multitude of tanks have been opened.

[0023] The process ends, for example, when the tank with the smallest or lowest fill level is opened and, consequently, all tanks are open.

[0024] It may also be provided that, before opening any tank of the multitude of tanks, a deviation of the fill level of the respective tank from a fill level of at least one other tank of the multitude of tanks is determined, and in the event that the deviation is greater than or equal to a predetermined diagnostic threshold, the tank remains closed and an error message is issued, reporting the respective tank as faulty.

[0025] If the fill level of a particular tank differs significantly from other tanks, i.e., is greater than or equal to a predefined diagnostic threshold, it can be assumed that the tank has a leak, allowing an error message to be issued, i.e., displayed on a display unit and / or stored in a memory for further functions, indicating that the respective tank is faulty.

[0026] It may also be provided that the procedure is executed multiple times and that the error message is only issued if the deviation in at least a specified proportion of the executions of the procedure is greater than or equal to the specified diagnostic threshold.

[0027] To minimize the probability of a false positive error message, it can only be issued if the deviation exceeds the diagnostic threshold several times, i.e., in several operating cycles.

[0028] It may also be provided that, before opening any tank among the multiple tanks, a deviation of the fill levels of all still closed tanks from an average fill level of all opened tanks is determined, and if the deviation is less than a predetermined process threshold, the process ends, and if the deviation is greater than or equal to the process threshold, the tank with the highest fill level is opened.

[0029] By using a process threshold, a tank can only be opened when the difference between the fill levels of the respective opened tanks and the highest fill level of the still-closed tank exceeds the process threshold. This ensures that the various tanks are opened successively, thus minimizing the risk of already opened tanks being refilled by opening subsequent tanks.

[0030] It may further be provided that a number of input conditions are checked at the start of the procedure and the procedure ends if an input condition is not met, wherein the number of input conditions includes that all tanks connected to a high-pressure line have a substantially the same pressure level but a different temperature at the start, that the volume of the individual tanks is greater than the total volume of the high-pressure line, that a temperature in each of the multiple tanks is known and is continuously determined during operation of the tank system, and that the individual fill levels of the respective tanks differ from each other by at least a lower predetermined procedure threshold and at most by a predetermined diagnostic threshold.

[0031] It may also be provided that the procedure is carried out directly after a filling process to fill the multitude of tanks.

[0032] By carrying out the presented procedure directly after a filling process, e.g. when driving away from a filling station, pressure differences generated during the filling process in the respective tanks are equalized or minimized.

[0033] According to a second aspect, the presented invention relates to a tank system for storing hydrogen.

[0034] The presented tank system comprises a plurality of tanks, each tank of the plurality of tanks comprising a temperature sensor for measuring a temperature in the respective tank and a tank valve for opening and closing the respective tank, and a computing unit, the computing unit being configured to carry out a possible embodiment of the presented method.

[0035] The presented method serves in particular to ensure the safe operation of the presented tank system.

[0036] In the context of the presented invention, a computing unit is to be understood as a computer, a processor, a control unit or any other programmable circuit.

[0037] According to a third aspect, the presented invention relates to a transport system. The presented transport system comprises a drive and a possible embodiment of the presented tank system, wherein the tank system is configured to supply the drive with fuel.

[0038] The presented transport system could be, for example, a vehicle, a ship, or an airplane.

[0039] The drive system of the presented transport system can in particular be a fuel cell system and / or a hydrogen engine.

[0040] Advantages described in detail for the method of operating a tank system according to the first aspect of the invention apply equally to the tank system for storing hydrogen according to the second aspect of the invention and to the transport system according to the third aspect of the invention, and vice versa.

[0041] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0042] They each show schematically:

[0043] Figure 1 shows a possible embodiment of the presented method,

[0044] Figure 2 shows a detailed representation of a possible embodiment of the presented method, and

[0045] Figure 3 shows a possible embodiment of the presented transport system with a possible embodiment of the presented tank system.

[0046] Figure 1 illustrates a method 100 for operating a tank system comprising a plurality of tanks. The method 100 comprises a first determination step 101, in which an individual temperature is determined in each tank of the plurality of tanks; a second determination step 103, in which an individual fill level of each tank of the plurality of tanks is determined based on the individual temperature determined in the first determination step 101; a first opening step 107, in which respective tanks of the plurality of tanks with the highest fill level are opened; and a second opening step 109, in which a number of further tanks of the plurality of tanks are opened as soon as the fill level of the opened tanks reaches a fill level of the further tanks.

[0047] In Fig. 2, the method 100 according to Fig. 1 is shown in detail.

[0048] In a preparatory step 201, it is checked whether the specified input conditions for carrying out procedure 100 are met. If this is the case, procedure 100 is started in a start step 203 and in a determination step 205 the individual fill levels of all tanks are calculated.

[0049] In diagnostic step 207, a difference is determined between the fill level of a given tank and at least one other tank, in particular an average fill level of all tanks. If the difference is greater than or equal to a predefined diagnostic threshold, an error message is issued in output step 209, reporting a fault in the respective tank.

[0050] If the difference is smaller than the diagnostic threshold, in a comparison step 211 the difference determined in diagnostic step 207 is compared with a predetermined procedure threshold and, if the difference is smaller than the procedure threshold, the procedure 100 is terminated in a termination step 213.

[0051] If the difference is greater than or equal to the procedure threshold, the tank(s) with the highest fill level are opened in opening step 215. If it is determined in verification step 217 that all tanks are open, the procedure is terminated in termination step 219.

[0052] If, in verification step 217, it is determined that not all tanks are open, the fill level of all tanks is determined again in an investigation step 221, and in a comparison step 223 it is determined whether the fill level of the already opened tanks corresponds to the fill level of the tank that is closed and has the highest fill level. If the condition of comparison step 223 is met, the tank that is closed and has the highest fill level is opened in an opening step 225.

[0053] Figure 3 shows a transport system 300 in the form of a vehicle. The vehicle includes a drive 301 in the form of an electric motor 303 coupled to a fuel cell system.

[0054] The fuel cell system is supplied with hydrogen via a tank system 305.

[0055] The tank system 305 comprises a multitude of tanks 307, each comprising a temperature sensor 309 and a tank valve 311.

[0056] The tanks 307 are connected via a high-pressure line 313.

[0057] Furthermore, the tank system 305 includes a tank control unit 315, which is configured to control the tank valves 311 in order to open and close them and to carry out the method 100 according to Fig. 1.

Claims

Claims 1. Method (100) for operating a tank system (305) comprising a plurality of tanks (307), wherein the method (100) comprises: Determining (101) an individual temperature in each tank (307) of the plurality of tanks (307), Determining (103) an individual fill level of each tank (307) of the plurality of tanks (307) based on the individual temperature, opening (105) respective tanks (307) of the plurality of tanks (307) whose fill level is greatest, Opening (107) a number of further tanks (307) of the multitude of tanks (307) as soon as the fill level of the opened tanks (307) reaches a fill level of the further tanks (307).

2. Method (100) according to claim 1, characterized in that the opening of the number of further tanks (307) is repeated until all tanks (100) of the plurality of tanks (307) are opened.

3. Method (100) according to claim 1 or 2, characterized in that before opening a respective tank (307) of the plurality of tanks (307), a deviation of the filling state of the respective tank (307) from a filling state of at least one further tank (307) of the plurality of tanks (307) is determined and in the event that the deviation is greater than or equal to a predetermined diagnostic threshold, the respective tank (307) remains closed and an error message is issued, which reports the respective tank (307) as faulty.

4. Method (100) according to claim 3, characterized in that the method (100) is executed several times and the error message is only issued if the deviation to at least a predetermined proportion of the executions of the method (100) is greater than or equal to the predetermined diagnostic threshold.

5. Method (100) according to one of the preceding claims, characterized in that, before opening a respective tank (307) of the plurality of tanks (307), a deviation of the filling states of all still closed tanks (307) from an average filling state of all opened tanks (307) is determined and, in the event that the deviation is less than a predetermined method threshold value, the method (100) ends and, in the event that the deviation is greater than or equal to the method threshold value, the tank (307) with the highest filling state is opened.

6. Method (100) according to one of the preceding claims, characterized in that a number of input conditions are checked at the start of the method (100) and the method (100) ends if an input condition is not met, wherein the number of input conditions comprises: all tanks (307) connected to a high-pressure line (313) have a substantially similar pressure level but a different temperature at the beginning, a total volume of the plurality of tanks (307) is greater than a total volume of the high-pressure line (313), a temperature in each of the respective tanks (307) of the plurality of tanks (307) is known and is continuously determined during operation of the tank system (305), individual fill levels of the respective tanks (307) differ from each other by at least one lower predetermined value. Procedure threshold and at most by a predetermined diagnostic threshold.

7. Method (100) according to one of the preceding claims, characterized in that the method (100) is carried out directly after a filling process for filling the plurality of tanks (307).

8. Method (100) according to one of the preceding claims, characterized in that the tank system (305) is a hydrogen tank system for storing hydrogen.

9. Tank system (305) for storing hydrogen, wherein the tank system (305) comprises: a plurality of tanks (307), wherein each tank (307) of the plurality of tanks (307) comprises a temperature sensor (309) for measuring a temperature in the respective tank (307) and a tank valve (311) for opening and closing the respective tank (307), a computing unit (315) wherein the computing unit (315) is configured to perform a method (100) according to any one of claims 1 to 8.

10. Transport system (300), wherein the transport system (300) comprises: a drive (301) and a tank system (305) according to claim 9, wherein the tank system (305) is configured to supply the drive (301) with fuel.

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