Freezing prevention control for fuel cell vehicles

Abstract

A method executed by a computer for controlling a power assembly of a vehicle comprising a plurality of fuel cell systems and an electrical energy storage system. The method includes estimating a vehicle parking time of the vehicle, determining whether anti-freezing is necessary during vehicle parking, and if it is determined that anti-freezing is unnecessary, stopping the engine of the fuel cell system without enabling anti-freezing. The method may include, if it is determined that anti-freezing is necessary, estimating a threshold time indicating a time when the cost of continuing to operate the fuel cell system exceeds the cost of stopping the engine of the fuel cell system, and if the estimated vehicle parking time ends after exceeding the threshold time, stopping the engine of the fuel cell system and enabling anti-freezing.

Description

Technical Field

[0001] The present disclosure generally relates to preventing freezing of a fuel cell system in a vehicle. The present disclosure further relates to a power assembly, a control unit, a vehicle, a computer program product, and a computer-readable medium.

[0002] The present disclosure can be applied to large vehicles such as trucks, buses, and construction equipment.

Background Art

[0003] A fuel cell is an electrochemical device that includes an electrolyte sandwiched between two electrodes such as an anode and a cathode. A solid polymer electrolyte fuel cell uses a proton exchange, solid polymer membrane electrolyte, and electrochemically converts reactants (such as fuel (hydrogen, etc.) and oxidant (such as oxygen or air)) to generate electric power. The anode receives hydrogen gas, and the cathode receives oxygen or air. A structure including a solid polymer membrane electrolyte sandwiched between these two electrodes is called a membrane electrode assembly (MEA). Usually, in order to provide a higher output voltage, a plurality of fuel cells are arranged together in a fuel cell stack. Also, a plurality of fuel cell stacks can be combined to form a fuel cell system.

[0004] The main by-products of the electrochemical reaction occurring in the fuel cell are water and heat. Therefore, proton exchange membrane fuel cell (PEMFC) vehicles (PEMFCVs) have been attracting increasing attention recently due to the advantages of low emissions or zero emissions.

[0005] For certain applications, during use, a fuel cell can be subjected to on / off repetitive duty cycles with inactive periods (e.g., storage or off-duty states) at various temperatures for various lengths of time. Generally, it is desirable to be able to reliably start a fuel cell in a short period of time. For example, in automotive applications, relatively fast and reliable start-up from an engine-off state may be required in sub-freezing ambient temperatures, such as environments far below freezing. At the same time, water management within the fuel cell at such temperatures presents difficulties due to the potential for ice formation, which is particularly undesirable during start-up from sub-freezing ambient temperatures. Since the MEA within the fuel cell system can be degraded and damaged by ice formation and expansion, the presence of liquid-phase water within the fuel cell system is particularly undesirable at sub-freezing temperatures. Generally, operating a fuel cell at sub-freezing temperatures can cause irreversible performance losses in the fuel cell, which can have a significant impact on the reliability and overall lifespan of the fuel cell. For example, structural changes may occur in the cathode catalyst later, which can thereby deform, or even separate from the membrane or delaminate.

[0006] Regarding the operation and storage of fuel cells assuming sub-freezing ambient conditions, various methods have been proposed. When a fuel cell is expected to be exposed to sub-freezing temperatures, certain start-up and shutdown techniques can be used. Freezing preparation procedures, if performed particularly frequently, can lead to certain degradation of the fuel cell's performance.

[0007] Accordingly, despite the progress achieved to date, there remains a need for improved methods for properly managing fuel cell systems under sub-freezing temperature conditions and in anticipation of such conditions. SUMMARY OF THE INVENTION

[0008] An object of embodiments of the present disclosure is to address the above need in improved techniques for managing, for example, a fuel cell system within a vehicle, in anticipation of sub-freezing ambient temperatures.

[0009] Embodiments of the present disclosure provide techniques to address the above needs. In particular, a fuel cell system within a vehicle's power assembly is managed to determine whether to perform freeze prevention or preparation, and when to perform it, considering data related to, for example, the vehicle's parking time, data related to the fuel cell system, ambient weather, and information related to the vehicle's driver.

[0010] Aspects of the present disclosure address the above needs by providing a method executed by a computer that controls a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system, the method determining whether to perform freeze prevention of the fuel cell system and / or when to perform it.

[0011] The method according to embodiments of the present disclosure enables making a determination regarding whether to perform freeze prevention in a fuel cell system of an electric vehicle. An electric vehicle, such as a fuel cell electric vehicle (FCEV), may be stopped, parked, or otherwise not in use, in which case the vehicle's fuel cell system(s) may be at risk of freezing. This determination may be made based at least on the vehicle's parking or standing time. Other non-limiting factors may include ambient conditions, the vehicle's power requirements while parked, the hydrogen consumption cost associated with keeping the fuel cell system operating, and the expected degradation cost associated with performing freeze prevention. The method according to embodiments of the present disclosure provides the advantage of improving the life and durability of the fuel cell system by reducing or eliminating the risk of degradation and damage to the fuel cell system. This makes it possible to reduce the costs associated with operating and maintaining a vehicle, such as an FCEV, including at least one fuel cell system. Also, the productivity and life of the vehicle may be extended.

[0012] According to one aspect of the present disclosure, a method executed by a computer for controlling a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system is provided. The method includes estimating a vehicle parking time of the vehicle, determining whether anti-freezing is necessary during the vehicle parking, and when it is determined that anti-freezing is unnecessary, shutting down the fuel cell system without activating anti-freezing.

[0013] The method may further include, when it is determined that anti-freezing is necessary, estimating a threshold time indicating a time when the cost of keeping the fuel cell system operating exceeds the cost of shutting down the fuel cell system, and when the estimated vehicle parking time ends after exceeding the threshold time, shutting down the fuel cell system and activating anti-freezing.

[0014] According to one aspect of the present disclosure, the object is achieved by the inventive concept disclosed herein. In this specification, as a technical effect, it is possible to determine whether to perform anti-freezing and when to perform it based on the vehicle parking time, ambient conditions, and other factors, and as a result, improvements and advantages such as a reduced risk of deterioration and damage of the fuel cell system are obtained. In this way, the life and durability of the fuel cell system are improved. The method according to an embodiment of the present disclosure enables making decisions regarding shutting down the fuel cell system(s) of the vehicle, performing anti-freezing of the fuel cell system, maintaining one or more of the fuel cell systems in an operating state, and restarting the fuel cell system(s) that have been shut down previously, taking into account various factors including the estimated vehicle parking time, ambient conditions, driver input, historical data, actual power requirements of the parked vehicle and / or auxiliary devices, and the costs associated with shutting down the fuel cell system to perform anti-freezing and the costs of maintaining one or more of the fuel cell systems in an operating state during vehicle parking. In this way, more accurate decisions can be made based on more information regarding the fuel cell system(s) of the vehicle, thereby advantageously improving the overall durability and thus the life of the fuel cell system.

[0015] In certain examples, the method further includes determining whether there is a power demand from the vehicle during vehicle parking, using at least an estimated time of vehicle parking.

[0016] In certain examples, determining whether there is a power demand from the vehicle during vehicle parking includes determining whether the driver of the vehicle is sleeping inside the vehicle during vehicle parking and / or whether the vehicle is parked.

[0017] In certain examples, whether anti-freezing is necessary during vehicle parking is determined when it is determined that there is no power demand from the vehicle during vehicle parking.

[0018] In certain examples, whether anti-freezing is necessary during vehicle parking is determined when it is determined that there is a power demand from the vehicle during vehicle parking and the power demand can be satisfied by an electrical energy storage system during vehicle parking.

[0019] In certain examples, when it is determined that there is a power demand from the vehicle during vehicle parking and the power demand cannot be satisfied by an electrical energy storage system during vehicle parking, the method further includes continuing to operate at least one fuel cell system of the fuel cell systems.

[0020] In certain examples, when the estimated time of vehicle parking ends before a threshold time, the method further includes (1) continuing to operate at least one fuel cell system of the fuel cell systems, or (2) restarting at least one fuel cell system.

[0021] In certain examples, at least one fuel cell system is restarted after a certain period during which multiple fuel cell systems are shut down.

[0022] In certain examples, the method further includes selecting at least one fuel cell system by comparing values representative of the healthy states of respective fuel cell systems among a plurality of fuel cell systems, wherein the at least one fuel cell system has the highest value representative of the healthy state of the at least one fuel cell system. The at least one fuel cell system can be selected to continue operating, or the at least one fuel cell system can be selected to be restarted, for example, to keep other fuel cell systems warm.

[0023] In certain examples, the threshold time is estimated using a first threshold time and a second threshold time, where the first threshold time is calculated for a case where the electrical energy storage system cannot store any of the power generated by the fuel cell system while the vehicle is parked, and the second threshold time is calculated for a case where the electrical energy storage system can store all of the power generated by the fuel cell system while the vehicle is parked.

[0024] In certain examples, the duration of vehicle parking is estimated using one or more of driver input, location information, ambient information, and historical data related to the operation of the vehicle.

[0025] In certain examples, whether anti-freezing is required during vehicle parking is determined using current ambient conditions and predicted ambient conditions.

[0026] According to one aspect of the present disclosure, a control unit for controlling a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system is provided, and the control unit is configured to execute the method according to an embodiment of the present disclosure.

[0027] According to one aspect of the present disclosure, a power assembly including a plurality of fuel cell systems and an electrical energy storage system is provided, and the power assembly further includes a control unit.

[0028] According to one aspect of the present disclosure, a vehicle is provided that includes a power assembly and / or communicates with a control unit.

[0029] According to one aspect of the present disclosure, a computer program product is provided that includes instructions which, when executed by at least one processor, cause the at least one processor to perform a method according to an embodiment of the present disclosure.

[0030] According to one aspect of the present disclosure, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program product that includes instructions which, when executed by at least one processor, cause the at least one processor to perform a method according to an embodiment of the present disclosure.

[0031] Additional features and advantages are disclosed in the following description, the claims, and the drawings. Further, additional advantages will be readily apparent to those skilled in the art from the present disclosure or will be recognized by practicing the present disclosure described herein. Also disclosed herein are control units, computer program products, and computer-readable media related to the above-described technical effects and corresponding advantages.

[0032] A more detailed description of aspects of the present disclosure, cited by way of example, follows with reference to the accompanying drawings.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2A

Figure 2B

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DETAILED DESCRIPTION OF THE INVENTION

[0034] Fuel cell systems are typically sensitive to low temperatures and need to be protected from freezing to avoid their degradation or damage. A vehicle or another device including a fuel cell system may be placed in an environment where the temperature is below 0°C and in some cases far below 0°C. In such situations, the risk of damage to the fuel cell increases, and thus the energy generation capacity of the fuel cell may be adversely affected. Furthermore, when a vehicle equipped with a power source including a fuel cell system stops or parks in a sub-freezing situation, the vehicle's ability to start quickly and properly may be affected. At the same time, the vehicle is required to be able to start properly under any ambient weather conditions including sub-freezing temperatures.

[0035] Various methods have been developed to protect a fuel cell system from freezing during engine shutdown of a vehicle or another device, or during storage of the fuel cell. These methods include external heating, purging of water before engine shutdown, use of antifreeze agents, continuous operation of the fuel cell system, etc. If freeze prevention fails, or if the fuel cell system cannot perform freeze prevention later, irreparable damage may occur to the fuel cell system. Further, freeze preparation places a certain load on the fuel cell system and promotes degradation of the fuel cell system that can ultimately reduce the lifespan of the fuel cell system and the host device equipped with such a system. Also, if the fuel cell system is not properly adapted to possible freezing conditions, the proper operation of a host device such as a vehicle using the fuel cell system for power generation is impaired.

[0036] Therefore, it is desirable to ensure that freeze prevention or freeze preparation is reliably performed at an appropriate time, and to perform freeze preparation of the fuel cell system less frequently in order to reduce the risk of degradation of the fuel cell system. Despite various approaches having advanced and been developed to date to prevent damage to the fuel cell under freezing ambient conditions, an improved method for properly protecting the fuel cell system from freezing at temperatures close to zero or below freezing is still needed.

[0037] Accordingly, an object of embodiments of the present disclosure is to provide a method for determining whether to perform freeze prevention and when to perform it, for example, a method for reducing or avoiding the risk of damage to the fuel cell system due to sub-freezing ambient temperatures and taking appropriate countermeasures.

[0038] The object is achieved by providing a method for controlling a fuel cell system in a vehicle, which includes determining whether to stop the engine of the fuel cell system without enabling anti-freezing, whether to stop the engine of the fuel cell system and enable anti-freezing, whether to maintain at least one of the fuel cell systems in the fuel cell system in an operating state, or whether to restart at least one of the fuel cell systems in the fuel cell system, based at least on the vehicle stop time.

[0039] Accordingly, provided herein is a method executed by a computer for controlling a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system (ESS). The method includes estimating the vehicle stop time of the vehicle, determining whether anti-freezing is required during vehicle stop, and if it is determined that anti-freezing is not required, stopping the engine of the fuel cell system without enabling anti-freezing. The method may further include, if it is determined that anti-freezing is required, estimating a threshold time indicating a time when the cost of keeping the fuel cell system operating exceeds the cost of stopping the engine of the fuel cell system, and if the estimated vehicle stop time exceeds and ends the threshold time, stopping the engine of the fuel cell system and enabling anti-freezing.

[0040] FIG. 1 shows a side view of a vehicle 10 according to an exemplary embodiment of the present invention. The vehicle 10 is shown as a truck, such as a large truck for towing one or more trailers (not shown). The vehicle 10 may be a fuel cell electric vehicle (FCEV). It should be understood that the present disclosure is not limited to any particular type of vehicle and may be used in other types of vehicles such as buses, construction equipment, such as wheel loaders or excavators, passenger cars, aircraft, and ships. The passenger car may be, for example, a taxi or another shared vehicle.

[0041] The present disclosure is applicable to other uses not related to vehicles as long as a power assembly including at least one fuel cell system and an electrical energy storage system (ESS) is utilized.

[0042] As schematically shown in FIG. 1, the vehicle 10 includes a power assembly 20. Here, the power assembly 20 can be used to supply power to one or more electric motors (not shown) used to generate propulsion force for the vehicle 10. The power assembly 20 can be used, additionally or alternatively, to supply power to other power-consuming parts (not shown) of the vehicle 10, such as an electric motor for a crane, an electric motor for a refrigerator system, an electric motor for an air-conditioning system, or any other power-consuming function of the vehicle 10. Thus, the power assembly 20 can be used, additionally or alternatively, to supply power to a power take-off (PTO) device, which is a device that transmits the mechanical power of the electric motor to another device. The vehicle 10 may include, be coupled to, or be associated with one or more PTO devices.

[0043] The power assembly 20 comprises at least one fuel cell unit or system 30, such as a plurality of fuel cell units or systems 30. Although not shown in detail, the fuel cell system may include two or more fuel cells that can together form a fuel cell stack. Further, the fuel cell system is configured to provide the necessary supplies such as hydrogen fuel (H2) and air, cooling, etc. to the fuel cell, and the fuel cell system can include various components not shown herein. At least one fuel cell system 30 may include a plurality of fuel cell systems, and each fuel cell system can include its own control system that can be communicatively connected to the control unit 40. The power assembly 20 may comprise three or more fuel cell systems, such as a single fuel cell system, two fuel cell systems, or three or more fuel cell systems. Also, when several fuel cell units or systems are provided, the fuel cell systems may be controllable independently or controllable in common. When controllable independently, each fuel cell system may be controlled to an on state or an off state regardless of the state(s) of other fuel cell unit(s). When two or more fuel cell systems are controllable in common, their on state or off state can be controlled in common, that is, all fuel cell systems can be controlled to the same state in common. Two fuel cell systems may, in some cases, be controlled depending on each other such that one fuel cell system is controlled to an on state or an off state according to the state(s) of the other fuel cell system(s).

[0044] Vehicle 10 further includes a control unit 40 according to an exemplary embodiment of the present disclosure. The control unit 40 may be used to control the power assembly 20. Although an on-board control unit 40 is shown, it should be understood that the control unit 40 may be a remote control unit 40, i.e., an off-board control unit, or a combination of an on-board and an off-board control unit. The control unit 40 may be configured to control the power assembly 20 by issuing control signals and receiving status information regarding the power assembly 20. For example, the control unit 40 may be configured to control the fuel cell system 30 by issuing control signals and receiving status information related to the fuel cell system 30. The control unit 40 may also be configured to receive information from various sensors including one or more of a temperature sensor, a humidity sensor, and other sensors included in or associated with the vehicle 10. For example, the temperature sensor may be arranged to measure the ambient temperature (i.e., the temperature outside and / or in the vicinity of the vehicle) that reflects the temperature to which the fuel cell system 30 is exposed. The control unit 40 may also be communicatively coupled to an internal database, an external database, or a combination thereof to receive historical data related to the driver's driving pattern and other events, data related to the auxiliary devices of the vehicle 10, historical data related to the use of the auxiliary devices, data related to the current position of the vehicle 10, current and predicted ambient conditions, historical data related to the ambient conditions of the current location, etc. The current position of the vehicle can be determined, for example, using a global positioning system (GPS) tracking device associated with the vehicle. Information regarding past, current, and / or predicted ambient situations may be received, for example, from an external weather service.

[0045] The control unit 40 can receive data regarding the driver's input, data from a predictive weather service, and other types of data. The control unit 40 may form part of the power assembly 20, as shown in FIG. 1. In some embodiments, the control unit 40 may be separate from the power assembly 20.

[0046] The control unit 40 is an electronic control unit and may include a processing circuit adapted to execute the computer program disclosed herein. The control unit 40 may include hardware and / or software for executing the method according to the embodiments of the present disclosure. The control unit 40 may be referred to as a computer. The control unit 40 may be constituted by one or more separate sub-control units. Further, the control unit 40 may communicate using wired and / or wireless communication means.

[0047] The power assembly 20 further includes an electrical energy storage system (ESS) 50. The ESS 50 stores surplus electrical energy generated by at least one fuel cell system 30 and may include one or more batteries for providing output power from the power assembly 20. The ESS 50 is electrically connected to the fuel cell system 30. The ESS 50 may include its own control system communicably connected to the control unit 40. The ESS 50 may also be further used to store energy regenerated during braking or may be configured to be charged by a charger, such as from an external power grid for example.

[0048] The power assembly 20 may further include power electronics (not shown) for converting the power generated by the fuel cell system 30 and / or the power supplied from the ESS 50 into power usable by a power consumer such as an electric motor or other power consuming unit. Further, in addition to or instead of what has been described above, the power assembly 20 may include various components such as a compressor, sensors, pumps, valves, and electrical components.

[0049] Although the present disclosure has been described with respect to vehicles such as trucks, aspects of the present disclosure are not limited to this particular vehicle and may be used with other vehicles such as passenger cars, off-road vehicles, aircraft, and ships. The present disclosure may also be applied to marine vessels and stationary applications such as grid-connected auxiliary generators or stand-alone generators.

[0050] Figures 2A and 2B are flowcharts of a method 200 for controlling a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system, according to an example. The power assembly may be, for example, the power assembly 20 of the vehicle 10 shown in FIG. 1, and the method 200 will be described below in connection with a vehicle such as the vehicle 10 of FIG. 1. The method 200 may be executed by a controller such as the control unit 40 of FIG. 1, for example.

[0051] The order of actions associated with the blocks of FIGS. 2A and 2B is shown as an example only, and the actions or steps may be performed in other orders. Optional actions are indicated by dashed lines.

[0052] As shown in FIG. 2A, the method 200 may start at block 202 when a vehicle stop request is received. For example, the vehicle may be engine stopped during a stop or parking, collectively referred to herein as a stop. During vehicle stop, it is assumed herein that the vehicle's engine is off. When the vehicle is stopped, one or more of the vehicle's fuel cell systems may initially remain on. At a particular point in time, during vehicle stop, one or more of the plurality of fuel cell systems may be turned off or on (e.g., turned back on or restarted). In some cases, one or more of the plurality of fuel cell systems may be turned on, while others of the plurality of fuel cell systems may be turned off.

[0053] When an engine stop request of the vehicle is received at block 202 and the vehicle is engine-stopped, the fuel cell system of the vehicle can continue to operate until it is determined that the method according to an example of the present disclosure also needs to engine-stop the fuel cell system. Thus, the vehicle stops.

[0054] At block 204, the time of vehicle stop or parking is determined or estimated. The parking time when the vehicle engine stops can be determined or estimated based on driver input, historical data related to the vehicle, such as historical data related to the driving pattern of the vehicle and other events (e.g., those recorded in vehicle log data), data related to the current position of the vehicle, the current surrounding situation and the predicted surrounding situation, time, and other data. For example, an input regarding the vehicle parking time may be received from the driver via an input device within the vehicle or an input device communicable with the vehicle, and the input indicates how long the vehicle parking is expected to be. The input device may be provided by a display device capable of receiving inputs from a user such as the driver, such as touch input, keyboard input, voice input, and inputs from various other input devices. The display device may be disposed at various locations in the vehicle, such as on the dashboard or center console. In some embodiments, the display device may be the display of a mobile device of a user such as the driver, and the driver input received via such a display device can be received remotely while the driver is not necessarily in proximity to the vehicle. Any other type of device may be used to receive an input regarding the vehicle stop or parking time from the driver or other person.

[0055] Historical data can indicate that a vehicle is used for a specific task at a specific time of day while the vehicle is parked at other times (e.g., at night). As another example, at a current location, it may be known that the vehicle is normally parked for a certain period of time. Also, depending on the type of vehicle (e.g., taxi, public transportation vehicle, long-distance vehicle, etc.), the vehicle may experience different start / stop patterns that can be predicted based on the vehicle's previous usage and previously recorded data. As another factor, in some cases, the driver shift and laws that define the time a driver can be on the road and / or the time a driver needs to take a break may be considered when determining the time and duration of vehicle parking. This may vary depending on the vehicle type. For example, in some cases, a driver may be instructed to stop for a certain period of time, e.g., for a mandatory break.

[0056] Regardless of the specific scenario, an estimated time when the vehicle is expected to be engine-off is determined.

[0057] In block 206, at least the estimated vehicle parking time is used to determine whether there is a power demand from the vehicle during vehicle parking, e.g., while the vehicle is parked. Power demands during vehicle parking may include, for example, power demands by PTO devices coupled to the vehicle such as cranes, refrigerators, air conditioners, heaters, etc. The power demand can be further estimated using ambient conditions, information about the vehicle auxiliary devices that are on, historical data regarding the usage of the vehicle auxiliary devices, and also other data. For example, the power demand may increase when the ambient conditions include a lower, e.g., sub-freezing, ambient temperature which may be the current temperature and / or the predicted temperature. Non-limiting examples of auxiliary devices include auxiliary batteries, mobile air conditioning systems, power window lifts, heating systems, cranes (e.g., hydraulic cranes), etc.

[0058] In some embodiments, at block 206, determining whether there is a power demand from the vehicle while the vehicle is parked includes determining whether the driver of the vehicle is asleep inside the vehicle while the vehicle is parked and / or whether the vehicle is parked. The vehicle may be, for example, a taxi or another ride-sharing vehicle, and the driver of the vehicle may be asleep inside the vehicle at a certain time. As another example, the vehicle may be a sleeper truck or tractor, such as a long-haul truck. The vehicle may also be, for example, a large vehicle performing a mission, and the driver of the large vehicle may sleep inside the vehicle while stopped and / or at night. It should be understood that sleep may include rest or other states while the vehicle is parked with the engine turned off. The cabin of the vehicle may have heating or cooling used while parked if the driver is inside the vehicle. Thus, FIG. 2A includes a decision block 205 that determines whether the driver is asleep inside the vehicle and / or whether the vehicle is parked, which may be a situation where certain energy / power demands need to be met while the vehicle is parked. In one example, whether the driver is sleeping inside the vehicle can be determined using historical data regarding the driver's actions, information regarding the vehicle's mission, the operation of certain auxiliary devices, sensor information (e.g., using one or more sensors that monitor the driver's behavior and state), and other information. If at block 205 it is determined that the driver is asleep inside the vehicle and / or that the vehicle is parked, method 200 proceeds to block 206, which determines whether there is a power demand from the vehicle while the vehicle is parked. The power demand from the vehicle may include the power demand from its PTO device. The processing at decision block 205 is shown as a separate step but may also be part of the processing at block 206.

[0059] At decision block 208, it can be determined whether the power demand can be met by the ESS while the vehicle is parked. In other words, an ESS, such as the ESS 50 of FIG. 1 for example, can determine whether it can meet the power demands of the vehicle and / or the PTO device while the vehicle is parked.

[0060] At decision block 208, if it is determined that the estimated power demand can be met by the ESS while the vehicle is parked, method 200 proceeds to decision block 210 to determine whether anti-freezing is required while the vehicle is parked. In some embodiments, whether anti-freezing is required while the vehicle is parked is determined when there is a power demand from the vehicle while the vehicle is parked and it is determined that the power demand can be met or fulfilled by the electrical energy storage system while the vehicle is parked.

[0061] In some embodiments, whether anti-freezing is required while the vehicle is parked may be determined at decision block 210 when it is determined that there is no power demand from the vehicle while the vehicle is parked. This may occur, for example, as shown in FIG. 2A, when the driver is not in the vehicle while parked, such as when the driver is not sleeping or when the vehicle is not otherwise occupied while parked. In other words, this may occur when it is determined at decision block 205, as indicated by the dashed arrow 207, that the driver is not sleeping in the vehicle and / or when it is determined that the vehicle is not parked.

[0062] In some embodiments, whether anti-freezing is required while the vehicle is parked may be determined using current ambient conditions and predicted ambient conditions. For example, if it is expected that the ambient temperature (e.g., the temperature of the external or other environment where the vehicle is located) will drop below 0°C while the vehicle is parked, it may be determined that anti-freezing is required. The predicted ambient conditions may be received, for example, from a predicted weather service. Similarly, the current ambient temperature may be determined using, for example, one or more sensors and may be used when determining whether it is necessary to enable anti-freezing of the fuel cell system.

[0063] In some embodiments, whether anti-freezing is necessary during vehicle parking may be determined by using a thermal model of the fuel cell system to evaluate heat loss to the surrounding environment, which is a function of the ambient temperature. The thermal model may be, for example, a verified one-dimensional or multi-dimensional thermal model that calculates the temperature of individual fuel cells. In that case, the necessity of anti-freezing can be evaluated by measuring the temperature of individual fuel cells at the end plates of the fuel cell stack, i.e., the cell end temperature within the fuel cell stack, which may reach the freezing temperature earlier than other cells in the fuel cell system. Alternatively, a lumped stack model may be used, and the mass-average fuel cell stack temperature may be determined to evaluate the necessity of anti-freezing. The model used may operate based on, for example, ambient temperature input from a predicted weather service, measured ambient temperature input obtained from a temperature sensor outside the fuel cell system, or measured temperature input obtained from a temperature sensor inside the fuel cell system (e.g., within a cooling loop). In some cases, the thermal model may be generated as described, for example, in Henao, N., et al. (“PEMFC low temperature startup for electric vehicle,” IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012, pp. 2977-2982), Amamou, A., et al. (“Thermal Management Strategies for Cold Start of Automotive PEMFC,” 2015 IEEE Vehicle Power and Propulsion Conference (VPPC), 2015, pp. 1-6), and Khandelwal, M., et al. (“One-dimensional thermal model of cold-start in a polymer electrolyte fuel cell stack,” Journal of Power Sources, 2007, vol. 172, pp. 816-830).In Henao, N., et al. (2012), an energy management strategy using a lumped mass fuel cell stack thermal model was proposed and experimentally verified. In this strategy, assuming that the initial temperature of the fuel cell is known, the ideal time to start heating the fuel cell stack during cold start operation is estimated. Using a similar lumped model, the time for the fuel cell stack to reach the critical temperature can also be estimated. For example, in Amamou, A., et al. (2015), such a model was created to compare cold start strategies. In certain embodiments, the model described in Khandelwal, M., et al. (2007), which simulates the operation of individual cells with a one-dimensional transient model, may be used.

[0064] In decision block 210, if it is determined that anti-freezing is not necessary, in block 212, the fuel cell system can be shut down without enabling anti-freezing. Anti-freezing may not be required if the power requirements of the vehicle and / or its auxiliary devices, such as the PTO device, can be met by electrical energy storage. In some embodiments, anti-freezing may not be required when the vehicle and / or its auxiliary devices, such as the PTO device, do not require power during vehicle parking. For example, anti-freezing may not be required if the ambient temperature is not expected to drop below 0 °C, or if it is expected to drop below 0 °C during a period when there is no risk of the fuel cell system freezing.

[0065] If it is determined in decision block 210 that anti-freezing is necessary, method 200 indicates, in block 214, a threshold time t until the cost of continuing to operate the fuel cell system exceeds the cost of shutting down the fuel cell system. trIt follows to estimate this. This can also be called the break-even point between the so-called "heat preservation" and "thawing at startup" cold start strategies. When the fuel cell system is turned off, the fuel cell system provides no output and consumes no fuel at all. The fuel cell unit, when turned on, consumes fuel such as hydrogen (H2) and supplies output power that can be stored in the electrical energy storage system. Therefore, the costs associated with the consumption of the fuel cell occur when the fuel cell system is operating continuously. At the same time, when the fuel cell system shuts down, in this case, since the risk of freezing of the fuel cell system increases, costs also occur. The power stored in the electrical energy storage system is consumed to perform anti-freezing and then thaw the fuel cell system to an appropriate temperature before startup. The vehicle may be heated using an electric heating component and / or other heating devices mounted on or accessible from the vehicle. For example, a hydrogen heater such as a catalyst heater may be used, in which case the costs are different. Also, when using an external power source, the costs are different.

[0066] Threshold time t tr can be estimated using a first threshold time and a second threshold time. The first threshold time can be calculated for a case or scenario where the electrical energy storage system cannot store any of the power generated by the fuel cell system during vehicle parking. The second threshold time can be calculated for a case or scenario where the electrical energy storage system can store all of the power generated by the fuel cell system during vehicle parking. The first threshold time and the second threshold time may be determined by using information regarding the initial state of charge (SoC) and capacity of the electrical energy storage system such as a battery. For example, the first threshold time may be calculated for a scenario where the SoC is 100% at the start of the parking period, and the second threshold time may be calculated for a scenario where the SoC is 0% at the start of the parking period. For details of the calculation of t tr please refer to the description of FIG. 4 below.

[0067] Next, in decision block 216, it is determined whether the estimated vehicle parking time ends after the threshold time t tr . Thus, in block 216, it is determined whether the estimated vehicle parking time is longer than the period during which the cost of keeping the fuel cell system operating at the end exceeds the cost of shutting down the engine of the fuel cell system. In other words, when the threshold time t tr ends, it becomes more costly to keep one or more of the fuel cell systems operating than to shut down the engine of the fuel cell system.

[0068] If the estimated vehicle parking time ends after the threshold time t tr , then in block 218, method 200 includes shutting down the engine of the fuel cell system and enabling anti-freezing. Further, in some cases, if the estimated vehicle parking time is equal to the threshold time t tr , method 200 may similarly include shutting down the engine of the fuel cell system and enabling anti-freezing.

[0069] Anti-freezing may include external heaters, use of anti-freezing solutions, purging of water before engine shutdown, and other techniques. The specific anti-freezing method may depend on the power assembly, characteristics of the fuel cell system(s), and other factors.

[0070] In some embodiments, enabling anti-freezing includes selecting an anti-freezing method that is a method suitable for the fuel cell system.

[0071] If the estimated time for vehicle parking ends before the threshold time, method 200 includes keeping at least one of the fuel cell systems in an operating state, as shown in block 220. In some embodiments, if there is a power request from the vehicle during vehicle parking and it is determined that the power request cannot be satisfied by the electrical energy storage system during vehicle parking (as indicated by arrow 209 in FIG. 2A), method 200 similarly proceeds to block 220, which includes maintaining at least one fuel cell system of the fuel cell systems in an operating state. At least one fuel cell system of the fuel cell systems may maintain its operation to keep the rest of the fuel cell system warm, thereby preventing freezing.

[0072] In some embodiments, keeping at least one fuel cell system of the plurality of fuel cell systems of the vehicle in an operating state includes determining which of the fuel cell systems to keep in an operating state. The respective health states of the fuel cell systems of the vehicle may be used for this purpose. Thus, at least one fuel cell system may be selected in block 222 by comparing the values representing the respective health states of each of the plurality of fuel cell systems, and at least one fuel cell system has the highest value representing the health state of the at least one fuel cell system. Thus, the at least one fuel cell system selected is the one having the highest value representing its state of health (SoH).

[0073] The value representing the SoH of the fuel cell system (or the value of SoH) may be determined in a plurality of ways. For example, the polarization curve of the fuel cell system may be evaluated. The polarization curve that displays the voltage output of the fuel cell system for a given current density load may be used when analyzing the degradation process of the fuel cell. As the fuel cell system ages, the polarization curve of the fuel cell system changes. Thus, as the fuel cell system ages, for the same current, the voltage drops, thereby providing an indicator of the value of the SoH of the fuel cell system.

[0074] Also, in some examples, numerical methods and / or machine learning may be used to estimate or predict the SoH value of a fuel cell system using data regarding the conditions under which the fuel cell system was operating. For example, to predict the SoH value of a fuel cell system, the history of the operating conditions of the fuel cell system may be used.

[0075] FIG. 2B is another flowchart of method 200 of FIG. 2A for controlling a power assembly comprising a plurality of fuel cell systems and an electrical energy storage system, according to one example. FIG. 2B shows more details regarding the calculation and use of the threshold time t tr as shown more particularly below.

[0076] As shown in FIG. 2B, method 200 may determine at block 211 that anti-freezing is required and / or that the ESS cannot meet the power demand while the vehicle is stopped. For example, the "yes" arrow exiting decision block 210 in FIG. 2 indicates a situation where it has been determined that anti-freezing is required.

[0077] In some embodiments, if anti-freezing is required, at blocks 214 and 215 of FIG. 2B, a period t tr (threshold time) and t0 (initial engine stop time) may be calculated or estimated, respectively. The crossover point is represented by t tr such that it is more cost-effective to stop the fuel cell system to perform anti-freezing rather than continue operating the fuel cell system. If the vehicle stop period is longer than t tr , the fuel cell system is stopped and anti-freezing becomes effective. If the vehicle stop time is less than t tr , at least one fuel cell system can be kept operating to keep the other fuel cell systems warm and prevent freezing.

[0078] In embodiments of the present disclosure, t trThe estimation of t0 may be performed based on comparing the cost of hydrogen consumption incurred when the fuel cell system continues to operate (including the degradation cost for maintaining the fuel cell system in an operating state) with the degradation cost expected to occur when freeze prevention is performed. The fuel cell system is restarted when it is necessary to move the vehicle.

[0079] FIG. 4 is a graph 400 showing the calculation of the threshold time t tr when there is no energy / power demand during vehicle parking. Graph 400 shows the hydrogen consumption amount by the fuel cell system as a function of time. The threshold time t tr can be estimated using a first threshold time t1 and a second threshold time t2. The first threshold time t1 can be calculated for a scenario where the electrical energy storage system cannot store any of the power generated by the fuel cell system during vehicle parking, and the second threshold time t2 can be calculated for a scenario where the electrical energy storage system can store all of the power generated by the fuel cell system during vehicle parking. As shown in FIG. 4, the threshold time t tr is between the first threshold time t1 and the second threshold time t2. The first threshold time t1 and the second threshold time t2 are two extreme values calculated based on a scenario where the ESS (e.g., battery) cannot receive or store any power generated from the fuel cell system(s) at all (i.e., cannot charge the ESS) and a scenario where the ESS can receive or store all or all of the power generated from the fuel cell system during parking / vehicle stationary period, respectively. When the battery cannot receive any more power, the power can be dissipated, for example, to warm the vehicle's cabin space or in other ways, such as through a braking resistor that can dissipate excess energy.

[0080] Cost thresholds R1 and R2 for calculating the first threshold time t1 and the second threshold time t2 are indicated by the horizontal lines in FIG. 4. R1 indicates an acceptable threshold for a situation where the ESS cannot store any of the power generated from the fuel cell system(s), i.e., a situation where the ESS cannot be charged, while R2 indicates an acceptable threshold for a situation where the ESS can store all of the power supplied for charging from the fuel cell system. The theoretical basis behind this is that when an ESS such as a battery can be charged with the power generated from a fuel cell system, it can accept the high hydrogen consumption cost for keeping the system operating because it will be supplemented by the charged battery when the vehicle needs to be moved next.

[0081] The R1 threshold used when the battery cannot be charged can be determined using the freezing preparation and the amount of energy required to thaw the fuel cell system(s) after freezing. Also, when calculating the R1 threshold, deterioration due to startup and purge is considered.

[0082] Depending on the state of charge of the ESS when the vehicle is parked, the threshold time t tr may be between the first threshold time t1 and the second threshold time t2. Therefore, FIG. 4 shows that the threshold time t tr is between t1 and t2, and its position relative to the first threshold time t1 and the second threshold time t2 can vary depending on the state of charge of the ESS such as the battery at the initial time of parking. For example, when the battery is empty or nearly empty, the threshold time t tr may be close to the second threshold time t2. As another example, when the battery is full, the threshold time t tr may be close to the first threshold time t1. The hydrogen consumption line or the shape of the graph can be considered to be a straight line assuming that the fuel cell system is operating or functioning at a constant power level. However, the gradient and the shape of the hydrogen consumption graph (e.g., a curve) may change depending on the ambient conditions and the operation of the fuel cell system(s).

[0083] In some cases, the threshold time t tr may be referred to as the period from the time when the vehicle stopped due to engine stop until the end of the threshold time t tr . FIG. 4 shows, in the form of a linear graph, that the graph 400 passes through the points (t1, R1) and (t2, R2). The point where the graph 400 intersects the vertical line (parallel to the y-axis) passing through the threshold time t tr is the point at which it may be as cost-effective to stop the fuel cell system to prevent freezing as to keep the fuel cell system operating. However, at a time after the threshold time t tr , it may be more cost-effective to stop the fuel cell system to prevent freezing than to keep the fuel cell system operating. Similarly, before the threshold time t tr , it may be less cost-effective to stop the fuel cell system to prevent freezing compared to keeping the fuel cell system operating.

[0084] In some embodiments, at least one fuel cell system of the vehicle's power assembly can be restarted after a certain period during which multiple fuel cell systems are stopped. The specific period can be denoted as t0, which can be determined, for example, at block 215 of FIG. 2B. Thus, the fuel cell system of the vehicle's power assembly may be restarted before the ambient temperature drops to a point where freezing may occur, or before the fuel cell system itself reaches the freezing temperature. This is the case, for example, when the ambient temperature around a parked vehicle is high during the day, for example, above 0°C (e.g., at least 5°C or another temperature higher than zero), and drops below freezing at night. This case is shown in FIG. 5. FIG. 5 is another graph 500 showing the calculation of the threshold time t tr when the vehicle does not require energy / power during vehicle parking. The graph 500 shows the hydrogen consumption by the fuel cell system as a function of time.

[0085] In the example shown in FIG. 5, an additional time t0 is also the threshold time t trIt is included in the calculation. This time t0 represents the time during which the fuel cell system(s) is / are stopped. At time t0, the fuel cell system(s) that was / were previously stopped is / are restarted, and after this time t0, the hydrogen consumption cost begins to increase. The other calculations of the first and second threshold times t1 and t2, and R1 and R2 are the same as in the example of FIG. 4. However, in the example of FIG. 5, the threshold values R1 and R2 for calculating t1 and t2 may be lower than in the example of FIG. 4 in consideration of the possible increase in degradation caused by the restart of the fuel cell system(s).

[0086] FIG. 5 shows that the straight-line graph 500 passes through the points (t1, R1) and (t2, R2). The point where the graph 500 intersects the vertical line (parallel to the y-axis) passing through the threshold time t tr is the point at which it may be as cost-effective to stop the fuel cell system to perform freeze prevention as to keep the fuel cell system operating. However, at a point after the threshold time t tr it may be more cost-effective to stop the fuel cell system to perform freeze prevention than to keep the fuel cell system operating.

[0087] FIG. 6 shows that when there is an energy / power demand for the vehicle while the vehicle is parked, the threshold time t trThe first graph 600 and the second graph 602 used for the calculation of [[ID=]] are shown. The first graph 600 and the second graph 602 each show the hydrogen consumption by the fuel cell system(s) as a function of time. More specifically, both graphs represent the hydrogen consumed for the purpose of keeping the system warm and preventing freezing. Heat is a byproduct of power generation in the fuel cell system, and for a certain amount of power generated, a certain amount of heat is also generated. This heat can be used to keep the system warm. Graph 600 shows a situation where there is no power demand, and graph 602 represents a situation where there is a power demand. When the vehicle's power demand is met by the fuel cell system, the cost of hydrogen consumption over time to keep the fuel cell system operating to prevent freezing may be lower. The theoretical basis is that part of the hydrogen consumption is covered by meeting the vehicle's energy and power demands.

[0088] As shown in FIG. 6, for example, it can be assumed that the fuel cell system consumes hydrogen according to the first line graph 600 while providing a certain specific first amount of electric power (for example, 10 kW). However, in order to meet the vehicle's power demand, a certain specific second amount of electric power (for example, 5 kW not explicitly shown in FIG. 6) may be required. Therefore, the actual proportion of hydrogen consumed only for anti-freezing can be regarded as only the total hydrogen consumption. Using the exemplary values, when the first amount of electric power is greater than the second amount of electric power, the electric power consumed for anti-freezing can be considered as the remaining electric power, that is, the electric power obtained by subtracting the second amount of electric power from the first amount of electric power (in this example, 10 kW - 5 kW = 5 kW for anti-freezing). When the vehicle's power demand (for example, when the driver is sleeping in the vehicle or there is a power take-out demand) is greater than the electric power required for the fuel cell system to keep itself warm (for example, the second amount of electric power is 15 kW instead of 5 kW), the vehicle's power / energy demand can be regarded as greater than the first amount of electric power represented in graph 600. In this case, continuing with this example, the second line graph 602 may coincide with the x-axis, and the fuel cell system can be operable to meet the vehicle's power / energy demand without incurring additional costs for anti-freezing (for example, since 10 kW - 15 kW < 0 kW, the additional electric power required for anti-freezing is 0 kW). In this case, that is, when the fuel cell system is operating to meet the vehicle's power demand, heat for warming the system(s) is generated as a by-product, which can be called net generation that is free of charge, i.e., without additional cost. Therefore, the hydrogen consumption only for heating the fuel cell system becomes zero. As a result, the additional hydrogen consumption for anti-freezing becomes zero, and the second line graph 602 will coincide with the x-axis. However, it should be noted that in this case, the hydrogen consumption itself is not zero, but the hydrogen consumption for heating the fuel cell system is zero.

[0089] FIG. 6 shows that the straight-line graph 602 passes through the points (t1, R1) and (t2, R2). The graph 602 has a threshold time t trThe point where it intersects a vertical line (parallel to the y-axis) passing through is, then, the point at which it may be as cost-effective to stop the engine of the fuel cell system and perform freeze prevention as it is to keep the fuel cell system operating. However, at the threshold time t tr After this point, it may be more cost-effective to stop the engine of the fuel cell system and perform freeze prevention than to keep the fuel cell system operating.

[0090] Returning to FIG. 2B, in decision block 216, as in the process shown in FIG. 2A, it is determined whether the estimated vehicle stop time ends after the threshold time t tr . In this case, at block 218, method 200 includes stopping the engine of the fuel cell system and enabling freeze prevention. In some embodiments, enabling and performing freeze prevention includes selecting a freeze prevention method that is a method suitable for the fuel cell system.

[0091] If the estimated vehicle stop time ends before the threshold time t tr , method 200 can include (1) continuing to operate at least one of the fuel cell systems of the fuel cell system, or (2) restarting at least one of the fuel cell systems. The option of keeping at least one of the fuel cell systems of the fuel cell system in an operating state is shown in block 220, similar to FIG. 2A. Alternatively, at block 219 in FIG. 2B, after time t0, it may be determined whether restart of at least one fuel cell of the fuel cell system is necessary. As further shown in FIG. 2B, the process of block 219 can also be performed after the fuel cell system has been stopped and freeze prevention has been enabled at block 218.

[0092] In decision block 221, restart of at least one of the fuel cell systems among the plurality of fuel cell systems takes time t0It can be determined whether it is necessary after . If it is determined that at least one fuel cell system needs to be restarted, in block 223, at least one fuel cell system may be restarted. Alternatively, if it is determined that restart of at least one fuel cell system is not necessary, in block 225, the fuel cell system may remain in the engine-stopped state.

[0093] Figures 3A and 3B are flowcharts showing another example of a method 300 for controlling a power assembly of a vehicle including a plurality of fuel cell systems and an electrical energy storage system. The method 300 of Figures 3A and 3B is similar to the method 200 of Figures 2A and 2B. The method 300 can be executed by a controller unit such as the control unit 40 of Figure 1, for example.

[0094] The order of actions related to the blocks in Figures 3A and 3B is shown by way of example only, and the actions or steps may be executed in other orders. Also, although not shown in Figures 3A and 3B, one or more of the actions may be optional.

[0095] In Figure 3A, in block 302, the method 300 includes receiving a parking / engine stop request for the vehicle. For example, a driver may stop the engine of the vehicle. If the vehicle is an autonomous or semi-autonomous vehicle, the vehicle may be automatically stopped.

[0096] In block 304, after the vehicle has stopped, the vehicle stop time is determined. This may be performed using at least driver input, location data such as the vehicle's global positioning system (GPS) location, and historical data regarding the driver, historical data that may include vehicle operation, use of vehicle auxiliary devices, and the like.

[0097] In decision block 305, it may be determined whether the driver is sleeping in the vehicle and / or whether there is any PTO application related to the vehicle, such as a PTO device. If it is determined whether the driver is sleeping in the vehicle and / or whether there is a PTO application, in block 306, while the vehicle is parked, for example while the vehicle is stationary, the energy / power demand from the vehicle (referred to as power demand in this specification) may be further determined. The power demand during the vehicle parking period may include, for example, power demands by PTO devices connected or installed to the vehicle, such as cranes, refrigerators, air conditioners, heaters, etc. The power demand may be estimated using one or more of ambient conditions, the time of vehicle parking (determined in block 304), information regarding the vehicle auxiliary devices that are on, historical data regarding the usage status of the vehicle auxiliary devices, and other data. Non-limiting examples of auxiliary devices include auxiliary batteries, mobile air conditioning systems, electric window lifts, heating systems, cranes (e.g., hydraulic cranes), etc.

[0098] After the power demand from the vehicle is determined while the vehicle is parked, method 300 may proceed to block 308, where it can be determined whether the power demand can be met or fulfilled by the ESS while the vehicle is parked. If it is determined that the vehicle's power demand can be met by the ESS while the vehicle is parked, method 300 can proceed to block 310, where it is determined whether it is necessary to prevent freezing of the plurality of fuel cell systems of the vehicle while the vehicle is parked. However, if it is determined that the vehicle's power demand cannot be met by the ESS while the vehicle is parked, method 300 may proceed to block 320, and method 300 includes: (1) operating or maintaining one or more of the plurality of fuel cell systems based on the vehicle's power demand while the vehicle is parked; and (2) when it is necessary to maintain one of the plurality of fuel cell systems in an operating state (or on), selecting one of the plurality of fuel cell systems having the highest value representing the healthy state of the fuel cell system and continuing to keep the other fuel cell systems warm.

[0099] As shown in FIG. 3A, method 300 continues in FIG. 3B after decision block 310, which is shown again in FIG. 3B for clarity of illustration. As shown in FIG. 3B, the determination of whether freeze protection of a plurality of fuel cell systems of a vehicle is necessary during vehicle parking may be performed based on ambient conditions, which may be current or predicted conditions, for example, using data obtained from a predicted weather service(s).

[0100] If it is determined that freeze protection is not necessary, at block 312, the fuel cell system may be shut down and freeze protection is not enabled.

[0101] If it is determined that freeze protection is necessary, at block 314, a threshold time t tr and an engine shutdown time t0 may be calculated. These may also be calculated in separate steps, as shown in FIG. 2B (blocks 214 and 215). Next, at decision block 316, it may be determined whether the estimated time of vehicle parking is longer than the threshold time t tr (i.e., it ends after an elapsed time). In this case, method 300 includes, at block 318, shutting down the fuel cell system and performing freeze protection. And the fuel cell system may be heated before the next start or at the next start.

[0102] At decision block 316, the estimated time of vehicle parking is the threshold time t trIf it is determined to be shorter (i.e., end earlier), method 300 may proceed to block 322, where method 300 (1) selects a fuel cell system with a high state of health (SoH) value from a plurality of fuel cell systems and maintains it in an operating / operational state or restarts it after time t0, or (2) uses at least one operable fuel cell system among the plurality of fuel cell systems to keep the other fuel cell systems among the plurality of fuel cell systems warm. Thus, this process may include using data regarding the state of health of a plurality of fuel cell systems of a vehicle's power assembly, as shown in FIG. 3B.

[0103] To execute the method steps described herein, control unit 40 may be configured to execute the processes described in connection with FIGS. 2A, 2B, 3A, and 3B above and / or any other examples or embodiments herein. Control unit 40 may include a configuration as shown in FIGS. 7A and 7B, for example.

[0104] As shown in FIG. 7A, the control unit 40 may include an input and output interface 700 configured to communicate with any necessary components and / or entities of the embodiments herein to receive the system state from the ESS 50 and to receive position information, weather information, information regarding the driver's input, any type of historical data, information regarding at least one auxiliary device of the vehicle, information regarding the use of at least one auxiliary device of the vehicle, and any other information. The input and output interface 700 may include a wireless and / or wired receiver (not shown) and a wireless and / or wired transmitter (not shown). The input and output interface 700 may include a transmitter, a receiver, a transceiver, and / or one or more antennas. The control unit 40 may be disposed at any suitable location in the vehicle 10. The control unit 40 may use the input and output interface 700 to control and communicate with sensors, actuators, subsystems, and interfaces within the vehicle 10 by using any one or more of a controller area network (CAN), an Ethernet cable, Wi-Fi®, Bluetooth®, and other network interfaces. The control unit 40 may be configured to communicate with one or more external services, databases, and / or controllers via wireless communication technologies.

[0105] The methods described herein can be implemented via a processing circuit such as one or more processors, such as the processing circuit 760 of the control unit 40 shown in FIG. 7A, and computer program code for performing the functions, operations, and steps of the embodiments herein. The computer program code may be provided as a computer program medium in the form of a computer-readable storage medium that holds, for example, computer program code or computer-executable instructions for performing a method according to an embodiment of the present disclosure when loaded into the control unit 40 and executed by the processing circuit 760. Examples of computer-readable storage media can include a memory stick or any other suitable medium form capable of holding machine-readable data. Further, the computer program code may be provided on a server as program code and downloaded to the control unit 40.

[0106] The control unit 40 may further include a memory 770 comprising one or more memory units. The memory 770 contains instructions executable by the processing circuit 760 of the control unit 40. The memory 770 is configured to be used for storing, for example, information, data, etc. for performing the methods herein when executed in the control unit 40. The control unit 40 can further obtain information from an external memory.

[0107] In some embodiments, a computer program product 780 includes instructions, such as a software code portion, that cause at least one processor, such as the processing circuit 760, to perform the method steps described herein when executed on the at least one processor so as to be executed by the control unit 40.

[0108] In some embodiments, the computer-readable storage medium 790 stores a computer program product 780. The computer-readable storage medium 790 may be, for example, a disk, a Universal Serial Bus (USB) stick, etc. The computer-readable storage medium 790 may store a computer program product 780 that includes program code or instructions that, when executed on at least one processor, e.g., on the processing circuit 760, cause the at least one processor to execute the methods according to the embodiments herein.

[0109] As shown in FIG. 7B, the control unit 40 may include a receiving unit 702. The control unit 40, the processing circuit 760, and / or the receiving unit 702 may be configured to receive or detect an engine stop request of the vehicle.

[0110] The control unit 40 may further include an estimation unit 704. The control unit 40, the processing circuit 760, and / or the estimation unit 704 may be configured to estimate the vehicle parking time of the vehicle. The vehicle parking time may be estimated using one or more of driver input, position information, ambient information, and historical data related to the operation of the vehicle.

[0111] The control unit 40 may further include a determination unit 706. The control unit 40, the processing circuit 760, and / or the determination unit 706 may be configured to determine whether anti-freezing is necessary during vehicle parking. In some cases, whether anti-freezing is necessary during vehicle parking may be determined using current ambient conditions and predicted ambient conditions. In some embodiments, the estimation unit 704 and the determination unit 706 may be part of the same unit.

[0112] The control unit 40 may further include an engine stop unit 708. When it is determined that freeze prevention is not necessary, the control unit 40, the processing circuit 760, and / or the engine stop unit 708 may be configured to stop the fuel cell system without enabling freeze prevention. Therefore, freeze prevention of the fuel cell system is not executed when it is determined that freeze prevention is unnecessary. However, the engine stop unit 708 of the control unit 40 can control the fuel cell system and / or other components of the power assembly or the entire vehicle to execute freeze prevention of the fuel cell system in a determined necessary situation.

[0113] The control unit 40, the processing circuit 760, and / or the estimation unit 704 may further be configured to estimate a threshold time (threshold time t tr etc.) indicating a time when the cost of keeping the fuel cell system in an operating state exceeds the cost of stopping the fuel cell system. The threshold time may be estimated using a first threshold time and a second threshold time. The first threshold time can be calculated for the case where none of the electric power generated by the fuel cell system during vehicle stop can be stored in the electrical energy storage system, and the second threshold time can be calculated for the case where all of the electric power generated by the fuel cell system during vehicle stop can be stored in the electrical energy storage system.

[0114] When it is determined that the estimated time of vehicle stop ends after the threshold time, the control unit 40, the processing circuit 760, and / or the engine stop unit 708 may be further configured to stop the fuel cell system and enable freeze prevention.

[0115] The control unit 40 can further include a power estimation unit 710. The control unit 40, the processing circuit 760, and / or the power estimation unit 710 can be configured to determine whether there is a power demand from the vehicle during vehicle parking, using at least the estimated time of vehicle parking. Determining whether there is a power demand from the vehicle during vehicle parking may include determining whether the driver of the vehicle is sleeping inside the vehicle during vehicle parking and / or whether the vehicle is parked. The control unit 40, the processing circuit 760, and / or the power estimation unit 710 can be configured to determine whether there is a power demand from the vehicle during vehicle parking using various other information, such as, for example, information regarding auxiliary devices of the vehicle, current and / or predicted ambient conditions, and other information.

[0116] The control unit 40, the processing circuit 760, and / or the determination unit 706 can be configured to determine whether anti-freezing is necessary during vehicle parking, which is determined when it is determined that there is no power demand from the vehicle during vehicle parking. In one embodiment, when it is determined that there is a power demand from the vehicle during vehicle parking and the power demand can be satisfied during vehicle parking, it is determined whether anti-freezing is necessary during vehicle parking.

[0117] The control unit 40 can further include a fuel cell system control unit 712. The control unit 40, the processing circuit 760, and / or the fuel cell system control unit 712 can be configured to maintain at least one fuel cell system of the fuel cell system in an operating state when it is determined by the control unit 40, the processing circuit 760, and / or the power estimation unit 710 that there is a power demand from the vehicle during vehicle parking and the power demand cannot be satisfied during vehicle parking.

[0118] The control unit 40, the processing circuit 760, and / or the fuel cell system control unit 712, when the estimated time of vehicle parking is the threshold time t trIf it ended earlier, (1) at least one fuel cell system among the fuel cell systems may be maintained in an operating state, or (2) at least one fuel cell system may be configured to restart.

[0119] In a specific example, at least one fuel cell system can be restarted after a certain period during which a plurality of fuel cell systems are stopped. The control unit 40, the processing circuit 760, and / or the fuel cell system control unit 712 may be configured to restart a plurality of fuel cell systems.

[0120] The control unit 40 can further include a selection unit 714. The control unit 40, the processing circuit 760, and / or the selection unit 714 may be configured to select at least one fuel cell system by comparing values representing the soundness states of the respective fuel cell systems among a plurality of fuel cell systems, and at least one fuel cell system has the highest value representing the soundness state of the at least one fuel cell system. At least one fuel cell system can be selected to continue operating, or at least one fuel cell system can be selected to restart, for example, to keep other fuel cell systems warm. In a specific example, at least one fuel cell system may be selected to restart after a certain period during which a plurality of fuel cell systems are stopped. The fuel cell system may be selected from two or more fuel cell systems. If the vehicle includes one fuel cell system, that fuel cell system is selected.

[0121] The units of control unit 40 may be executed by processing circuit 760 as shown in FIG. 7A. It should be understood that the units of control unit 40 are shown as an example, since one or more of the units may be part of the same unit, or one or more of the units may have sub-units. For example, in some embodiments, fuel cell system control unit 712 and engine stop unit 708 may be part of the same unit of controller 40. Also, one or more of fuel cell system control unit 712, engine stop unit 708, and selection unit 714 may be part of the same unit. In some embodiments, one or more of estimation unit 704, determination unit 706, and power estimation unit 710 may be part of the same unit.

[0122] Those skilled in the art will understand that the units within control unit 40 described above may refer to a combination of analog and digital circuits and / or one or more processors configured, for example, by software and / or firmware stored in control unit 40, and that when the software and / or firmware is executed by the respective one or more processors, the methods according to embodiments of the present disclosure can be executed. One or more of these processors and other digital hardware may be included in a single application specific integrated circuit (ASIC), or several processors and various digital hardware may be distributed among several individual components, whether individually packaged or assembled on a system-on-chip, regardless of how they are packaged.

[0123] The operational steps described in any of the exemplary aspects of this specification are explained for purposes of providing examples and discussion. The steps may be executed by hardware components, embodied in machine-executable instructions for causing a processor to execute the steps, or executed by a combination of hardware and software. Although a particular order of method steps may be shown or described, the order of the steps may differ. Additionally, two or more steps may be executed in parallel or partially in parallel.

[0124] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. The terms “comprises,” “comprising,” “includes” and / or “including,” when used herein, specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0125] The terms, first, second, etc. may be used herein to describe various elements, but it is understood that these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present disclosure, a first element may be termed a second element and, similarly, a second element may be termed a first element.

[0126] Relative terms such as "lower", "upper", "top", "bottom", "horizontal", or "vertical" may be used herein to describe the relationship of one element to another as shown in the figures. It will be understood that these terms, and the terms described above, are intended to encompass different orientations of the device in addition to the orientation shown in the figures. When an element is referred to as being "connected" or "coupled" to another element, it will be understood that the element may be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, no intervening elements are present.

[0127] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms used herein should be construed to have a meaning that is consistent with their meaning in the context of this specification and the relevant art, and should not be construed in an idealized or overly formal sense unless expressly so defined herein.

[0128] It will be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings, but rather, one of ordinary skill in the art will recognize that many variations and modifications may be made within the scope of the present disclosure and the appended claims. The drawings and the specification disclose embodiments for purposes of illustration only, and the scope of the inventive concept is set forth in the following claims.

Claims

1. A method executed by a computer for controlling a power assembly (20) of a vehicle (10) comprising a plurality of fuel cell systems (30) and an electrical energy storage system (50), estimating the vehicle parking time of the vehicle (204); determining whether anti-freezing is necessary during the vehicle parking (210); when it is determined that anti-freezing is not necessary, stopping the engine of the fuel cell system without enabling anti-freezing (212); The method, including the above.

2. when it is determined that anti-freezing is necessary, estimating a threshold time indicating a time when the cost of continuing to operate the fuel cell system exceeds the cost of stopping the engine of the fuel cell system (214); when the estimated time of the vehicle parking has ended after exceeding the threshold time (216), stopping the engine of the fuel cell system and enabling anti-freezing (218); The method according to claim 1, further including the above.

3. The method according to claim 2, further including determining whether there is a power demand from the vehicle during the vehicle parking (206) using at least the estimated time of the vehicle parking.

4. Determining whether there is a power demand from the vehicle during the vehicle parking includes determining whether the driver of the vehicle is sleeping in the vehicle during the vehicle parking and / or whether the vehicle is parked (205). The method according to claim 3.

5. The method according to claim 3 or 4, wherein whether anti-freezing is necessary during the vehicle parking is determined when it is determined that there is no power demand from the vehicle during the vehicle parking.

6. The method according to claim 3 or 4, wherein whether anti-freezing is necessary during the vehicle parking is determined when it is determined that there is a power demand from the vehicle during the vehicle parking and the power demand can be satisfied by the electrical energy storage system during the vehicle parking.

7. The method according to claim 3 or 4, further including continuing to operate at least one of the fuel cell systems of the fuel cell system when it is determined that there is a power demand from the vehicle during the vehicle parking and the power demand cannot be satisfied by the electrical energy storage system during the vehicle parking (220).

8. If the estimated time of the vehicle stop ends before the threshold time, (1) continuing to operate at least one fuel cell system among the fuel cell systems, or (2) restarting the at least one fuel cell system, further comprising the method according to any one of claims 2 to 7.

9. The method according to claim 8, wherein the at least one fuel cell system is restarted after a certain period during which the plurality of fuel cell systems are stopped.

10. Further comprising selecting (222) the at least one fuel cell system by comparing values representing the soundness states of the respective fuel cell systems among the plurality of fuel cell systems, wherein the at least one fuel cell system has the highest value representing the soundness state of the at least one fuel cell system, the method according to any one of claims 7 to 9.

11. The threshold time is estimated using a first threshold time and a second threshold time, the first threshold time being calculated for the case where none of the electric power generated by the fuel cell system during the vehicle stop can be stored in the electrical energy storage system, and the second threshold time being calculated for the case where all of the electric power generated by the fuel cell system during the vehicle stop can be stored in the electrical energy storage system, the method according to any one of claims 1 to 10.

12. The time of the vehicle stop is estimated using one or more of driver input, position information, surrounding information, and historical data related to the operation of the vehicle, the method according to any one of claims 1 to 11.

13. Whether anti-freezing is required during the vehicle stop is determined using current surrounding conditions and predicted surrounding conditions, the method according to any one of claims 1 to 12.

14. A control unit (40) for controlling a power assembly (20) of a vehicle (10) comprising a plurality of fuel cell systems (30) and an electrical energy storage system (50), the control unit (40) being configured to execute the method according to any one of claims 1 to 13.

15. A power assembly (20) comprising a plurality of fuel cell systems (30) and an electrical energy storage system (50), the power assembly (20) further comprising a control unit (40) according to claim 14.

16. A vehicle (10) comprising the power assembly (20) according to claim 14 and / or communicating with the control unit (40) according to claim 15.

17. A computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to perform the method according to any one of claims 1 to 13.

18. A computer-readable storage medium storing a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to perform the method according to any one of claims 1 to 13.

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