Process and system for converting energy

Abstract

The presented invention relates to a method (100) for operating a system (200) for converting energy, wherein the method (100) comprises: - Deactivating (101) an energy converter (205) of the system (200), - Determining (103) a shut-off pressure in at least one tank (203) of a tank system (201) for storing hydrogen, - Comparison (105) of the determined shut-off pressure with a pressure threshold value, - Activation (107) of the energy converter (205) in the event that the determined shutdown pressure is greater than or equal to the pressure threshold value, so that hydrogen from the at least one tank (203) is consumed by the energy converter (205) and converted into electrical energy, - Storing (109) electrical energy provided by the energy converter (205) in an energy storage device (207) of the system (200).

Description

[0001] The presented invention relates to a method for operating an energy conversion system, an energy conversion system and a vehicle according to the appended claims. State of the art

[0002] Despite thermal insulation, tank systems for cryogenic liquid hydrogen experience a small amount of heat input. This heat input leads to an isochoric pressure increase in the tank during downtimes when no hydrogen is being drawn from a particular tank. When a maximum permissible tank pressure is reached, this heat input requires a venting, i.e., a so-called "boil-off," of at least a portion of the hydrogen stored in the tank. This venting accordingly has a negative impact on the energy efficiency of a system consuming hydrogen. Disclosure of the invention

[0003] Within the scope of the invention presented, a system for converting energy and a method for operating the system, as well as a vehicle, are presented. Further features and details of the invention emerge from the respective subclaims, 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 system according to the invention or the vehicle according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0004] The invention presented serves in particular to minimize a loss of hydrogen by blowing it off from a tank and to maximize the energy efficiency of a corresponding system for converting energy.

[0005] Thus, according to a first aspect of the invention presented, a method for operating a system for converting energy is presented.

[0006] The presented method comprises deactivating an energy converter of the system, determining a shut-off pressure in at least one tank of a tank system for storing hydrogen, comparing the determined shut-off pressure with a pressure threshold, activating the energy converter in the event that the determined shut-off pressure is greater than or equal to the pressure threshold, so that hydrogen from the at least one tank is consumed by the energy converter and converted into electrical energy, and storing electrical energy provided by the energy converter in an energy storage device of the system.

[0007] In the context of the present invention, an energy conversion process is understood to mean, in particular, a process in which chemical energy stored in a quantity of hydrogen is converted into electrical energy. For this purpose, the hydrogen can be burned or oxidized by an energy converter, e.g., in the form of an internal combustion engine, in particular a piston engine, and / or by a fuel cell system, i.e., converted into water by reacting with oxygen to generate electrical energy.

[0008] The invention presented is based on the principle that an increase in pressure in a tank, which leads to a release of hydrogen, is prevented or at least delayed by reducing the pressure in the tank by removing hydrogen. The removal of hydrogen is made possible by activating an energy converter coupled to the tank to consume the hydrogen. Accordingly, the energy converter converts the hydrogen removed from the tank into electrical energy and ultimately stores it temporarily in an energy storage device. This means that the amount of hydrogen required to reduce the pressure in the tank is not released into the environment, but is stored in the energy storage device in the form of electrical energy and possibly excreted in the form of water.

[0009] In the context of the invention presented, an energy storage device is understood to mean a storage device for storing electrical energy, such as a battery.

[0010] Accordingly, the energy converter provided according to the invention is operated in a supplementary mode, which is in addition to a regular mode in which, for example, a vehicle is moved. In the supplementary mode, the energy converter provides electrical energy without, for example, a vehicle being moved, so that the amount of electrical energy provided by the energy converter can be fed directly into the energy storage device to be used, for example, for subsequent movement of the vehicle.

[0011] Furthermore, the presented method enables spontaneous refueling of the tank, since the operation of the energy converter creates a capacity for absorbing hydrogen into the tank.

[0012] Accordingly, the method presented avoids the need to travel a certain distance at tank pressures above the pressure threshold of, for example, 16 bar in order to reduce the pressure in the tank below a pressure provided by a filling station by withdrawing hydrogen during driving, thus enabling a refueling process in the first place.

[0013] It can be provided that the energy converter is operated until a pressure in the at least one tank is less than or equal to a predetermined nominal pressure or the energy storage device is fully charged.

[0014] In order to minimize the release of hydrogen into the environment, the energy converter must be operated until the pressure in at least one tank is less than or equal to a specified nominal pressure of, for example, 6 bar.

[0015] It can further be provided that, in the event that the energy storage device is fully charged and a pressure in the at least one tank is greater than a predetermined safety threshold, hydrogen is released from the at least one tank.

[0016] To prevent damage to the energy storage system, the release of hydrogen into the environment can be initiated when the energy storage system is fully charged and the pressure in at least one tank is greater than a safety threshold, which can, for example, correspond to the specified nominal pressure.

[0017] It can further be provided that the energy storage device is emptied to a target charge level during a control operation of the system before the energy converter is deactivated in order to maintain a capacity to absorb an amount of electrical energy provided by the activation of the energy converter.

[0018] Using predictive route planning, which, for example, evaluates route information collected over several days for a particular vehicle, it is possible to determine expected parking times, parking durations, refueling times, refueling station locations, route distances, their power requirements, their geodetic elevation profile, and a weather forecast, such as the temperature at system startup, for the future. Based on this route information, the capacity for absorbing the amount of electrical energy provided by activating the energy converter can be determined and adjusted accordingly on the energy storage system.

[0019] For example, based on a predicted shutdown time during a journey in a vehicle, the energy storage device can be discharged to a battery charge level required to absorb energy for adjusting the pressure in the tank.

[0020] Furthermore, when determining the capacity to absorb the amount of electrical energy provided by activating the energy converter, a predicted geodetic elevation profile of the next route after a current shutdown and the expected ambient temperatures can be taken into account. For example, if a subsequent trip is expected to involve a "downhill descent" from a high geodetic altitude, the energy storage device can be discharged less extensively before the shutdown time so that energy can be recuperated into the energy storage device during the subsequent expected downhill descent.

[0021] However, if low ambient temperatures are expected during a subsequent journey, a buffer of electrical energy can be kept available for heating support or a cold start of the energy converter.

[0022] It can further be provided that the target charge level is determined by means of a machine learner, which assigns a corresponding target charge level to the respective determined route information and / or weather information.

[0023] Using a machine learner, such as an artificial neural network, route information and / or weather information, collected, for example, via a vehicle's sensors, can be automatically assigned a corresponding value for the energy storage capacity to be maintained. For this purpose, the machine learner can be trained, for example, using training data that has been labeled with a ground truth by a user. Alternatively, the machine learner can train itself and receive, for example, the activation of a hydrogen release from the tank as feedback.

[0024] It can further be provided that only gaseous hydrogen is taken from the at least one tank to activate the energy converter.

[0025] By removing only gaseous hydrogen, for example by controlling a valve arranged at the top of the at least one tank, a mass flow from the at least one tank is maximized and a pressure in the at least one tank is reduced accordingly quickly.

[0026] According to a second aspect, the presented invention relates to a system for converting energy.

[0027] The presented system comprises a tank system with at least one tank for storing hydrogen, an energy converter for converting chemical energy into electrical energy, an energy storage device for storing electrical energy and a computing unit, wherein the computing unit is configured to carry out a possible embodiment of the presented method.

[0028] In the context of the invention presented, a computing unit is understood to mean a computer, a processor, a control unit or any other programmable circuit.

[0029] It can be provided that the energy converter comprises an internal combustion engine coupled to a generator and / or a fuel cell system.

[0030] It may further be provided that the tank system is configured to store hydrogen in saturated form or subcooled form or in cryostatically compressed form.

[0031] Since subcooled or cooled fluids expand particularly strongly in response to heat input, the presented invention is particularly suitable for tank systems for storing such fluids.

[0032] According to a third aspect, the presented invention relates to a vehicle comprising a possible embodiment of the presented system.

[0033] Advantages described in detail for the method of operating an energy conversion system according to the first aspect of the invention apply equally to the energy conversion system according to the second aspect of the invention and the vehicle according to the third aspect of the invention.

[0034] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. Drawings

[0035] They show: Fig. 1 a possible design of the presented procedure, Fig. 2 a possible design of the presented system, Fig. 3 a possible design of the presented vehicle. Description of the embodiments

[0036] In Fig. 1 shows a method 100 for operating an energy conversion system.

[0037] The presented method 100 comprises a deactivation step 101, in which an energy converter of the system is deactivated, for example in response to a user input, a determination step 103, in which a shut-off pressure in at least one tank of a tank system for storing hydrogen is determined, a comparison step 105, in which the determined shut-off pressure is compared with a pressure threshold value, an activation step 107, in which the energy converter is activated in the event that the determined shut-off pressure is greater than or equal to the pressure threshold value, so that hydrogen from the at least one tank is consumed by the energy converter and converted into electrical energy, and a storage step 109, in which electrical energy provided by the energy converter is stored in an energy storage device of the system.

[0038] In Fig. 2 shows a system 200 for converting energy.

[0039] The system 200 comprises a tank system 201 with a tank 203 for storing hydrogen, an energy converter 205 in the form of a fuel cell system for converting chemical energy into electrical energy, an energy storage device 207 in the form of a battery for storing electrical energy, and a computing unit 209.

[0040] The computing unit 207 is configured to carry out the method 100 according to Fig. 1 to execute.

[0041] In Fig. 3, a vehicle 300 is shown. The vehicle 300 includes the system 200 according to Fig. 2.

Claims

[1] A method (100) for operating a system (200) for converting energy, the method (100) comprising: - deactivating (101) an energy converter (205) of the system (200), - determining (103) a shut-off pressure in at least one tank (203) of a tank system (201) for storing hydrogen, - comparing (105) the determined shut-off pressure with a pressure threshold value, - activating (107) the energy converter (205) in the event that the determined shut-off pressure is greater than or equal to the pressure threshold value, so that hydrogen from the at least one tank (203) is consumed by the energy converter (205) and converted into electrical energy, - storing (109) electrical energy provided by the energy converter (205) in an energy store (207) of the system (200). [2] Method (100) according to claim 1, characterized bythat the energy converter (205) is operated until a pressure in the at least one tank (203) is less than or equal to a predetermined nominal pressure or the energy store (207) is fully charged. [3] Method (100) according to one of the preceding claims, characterized by that in the event that the energy storage device (207) is fully charged and a pressure in the at least one tank (203) is greater than a predetermined safety threshold value, hydrogen is blown off from the at least one tank (203). [4] Method (100) according to one of the preceding claims, characterized by that the energy storage device (207) is emptied to a desired charge level during a control operation of the system (200) before the energy converter (205) is deactivated in order to maintain a capacity for absorbing an amount of electrical energy provided by the activation of the energy converter (205). [5] Method (100) according to claim 4, characterized by that the target charge level is determined as a function of route information about a route traveled by a vehicle (300) comprising the system (200) and / or weather information about a weather in an environment of the system (200). [6] Method (100) according to claim 5, characterized by that the target charge level is determined by means of a machine learner, which assigns a corresponding target charge level to the respective determined route information and / or weather information. [7] Method (100) according to one of the preceding claims, characterized by that to activate the energy converter only gaseous hydrogen is taken from the at least one tank (203). [8] System (200) for converting energy, the system (200) comprising: - a tank system (201) with at least one tank (203) for storing hydrogen, - an energy converter (205) for converting chemical energy into electrical energy, - an energy storage device (207) for storing electrical energy, - a computing unit (209), wherein the computing unit (209) is configured to execute a method (100) according to one of claims 1 to 7. [9] System (200) according to claim 8, characterized by that the energy converter (205) comprises an internal combustion engine coupled to a generator and / or a fuel cell system. [10] System (200) according to claim 8 or 9, characterized by that the tank system (201) is configured to store hydrogen in saturated form or subcooled form or in cryostatically compressed form. [11] Vehicle (300), wherein the vehicle (300) comprises a system (200) according to any one of claims 8 to 10.

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