Marine battery power systems and their control methods

Abstract

This invention provides a marine battery power system and its control method, belonging to the field of marine power technology. The system includes: a fuel tank, a blower, a first heat exchanger, a second heat exchanger, a fuel cell stack, a DC-DC converter, a combustion chamber, and a lithium battery. The anode sides of the fuel tank, the first heat exchanger, and the fuel cell stack are sequentially connected; the cathode sides of the blower, the second heat exchanger, and the fuel cell stack are sequentially connected; and the reaction gas output terminal of the fuel cell stack is connected to the combustion chamber. The fuel cell stack is also electrically connected to a marine busbar for powering the marine propulsion system via the DC-DC converter. The marine battery power system provided by this invention, through the fuel tank, blower, first heat exchanger, second heat exchanger, fuel cell stack, DC-DC converter, and combustion chamber forming a solid oxide fuel cell structure, combined with a lithium battery to power the marine propulsion system, can solve the problems of existing marine power systems being unsuitable for long-distance ocean voyages and having short service life.

Description

Technical Field

[0001] This invention relates to the field of marine electric technology, specifically to a marine battery power system and its control method. Background Technology

[0002] Existing ship electrical systems often use all-lithium batteries for power. However, due to the relatively low energy density of lithium batteries, they are unsuitable for long-distance ocean voyages. Furthermore, frequent use of all-lithium batteries reduces their lifespan. Therefore, existing ship electrical systems suffer from the problems of being unsuitable for long-distance ocean voyages and having a short lifespan. Summary of the Invention

[0003] In view of this, it is necessary to provide a marine battery power system and its control method to solve the technical problems of existing marine power systems being unable to adapt to ocean voyages and having a short service life.

[0004] To address the aforementioned problems, the present invention provides a marine battery power system comprising: a fuel tank, a blower, a first heat exchanger, a second heat exchanger, a fuel cell stack, a DC-DC converter, a combustion chamber, and a lithium battery.

[0005] The fuel tank, the first heat exchanger, and the anode side of the fuel cell stack are connected in sequence. The blower, the second heat exchanger, and the cathode side of the fuel cell stack are connected in sequence. The reaction gas output end of the fuel cell stack is connected to the combustion chamber.

[0006] The fuel cell stack is also electrically connected to a marine busbar for powering the marine propulsion system via the DC-DC converter.

[0007] In one possible implementation, both the first heat exchanger and the second heat exchanger are plate heat exchangers.

[0008] In one possible implementation, the fuel tank is used to store fuel gas and water.

[0009] In one possible implementation, the number of fuel cell stacks is at least two, and each stack includes multiple fuel cells connected in parallel.

[0010] In one possible implementation, the number of DC converters is the same as the number of fuel cell stacks, and each fuel cell stack is electrically connected to the marine bus via a corresponding DC converter.

[0011] In one possible implementation, the exhaust gas outlet of the combustion chamber is connected to the first heat exchanger.

[0012] In one possible implementation, the first heat exchanger is also connected to the second heat exchanger.

[0013] In one possible implementation, the marine battery power system further includes: a first diverter valve and a second diverter valve;

[0014] The first heat exchanger is connected to the anode side of different fuel cells in the stack via the first diversion valve, and the second heat exchanger is connected to the cathode side of different fuel cells in the stack via the second diversion valve.

[0015] On the other hand, the present invention also provides a control method for a marine battery power system, the method being applied to the marine battery power system described in any of the above claims, the method comprising:

[0016] When the marine battery power system is in pure electric mode, control the output of electrical energy from the lithium battery;

[0017] When the state of charge of the lithium battery is below a preset threshold, or when the marine battery power system is in hybrid mode, the fuel tank is controlled to deliver fuel to the fuel cell stack for combustion, so as to output electrical energy through the fuel cell stack.

[0018] In one possible implementation, the control method for the marine battery power system further includes:

[0019] Construct a multi-scale model corresponding to the marine battery power system;

[0020] The optimal power corresponding to different fuel cell stacks is determined based on the multi-scale model, and the operating state of the fuel cell stack is controlled based on the optimal power.

[0021] The beneficial effects of adopting the above-described implementation method are as follows: The marine battery power system and its control method provided by this invention constitute a solid oxide fuel cell structure through a fuel tank, a blower, a first heat exchanger, a second heat exchanger, a fuel cell stack, a DC-DC converter, and a combustion chamber. This solid oxide fuel cell, combined with a lithium battery, forms a hybrid power battery to power the marine propulsion system. The fuel tank can store sufficient fuel, and the combination of the solid oxide fuel cell structure and the lithium battery provides ample electrical energy to aid in long-distance ocean voyages. Furthermore, when the lithium battery's state of charge is low, the solid oxide fuel cell structure can charge the lithium battery, preventing over-discharge and shortening its lifespan. Therefore, the marine battery power system provided by this invention can solve the technical problems of existing marine power systems being unable to adapt to long-distance ocean voyages and having a short service life. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of a structural embodiment of the marine battery power system provided by the present invention;

[0024] Figure 2 A flowchart of an embodiment of the control method for a marine battery power system provided by the present invention;

[0025] Figure 3 A flowchart of another embodiment of the control method for a marine battery power system provided by the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the principle of optimal energy allocation based on a multi-scale model provided by the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0029] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0030] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] This invention provides a marine battery power system and its control method, which will be described below.

[0033] like Figure 1 As shown, the present invention provides a marine battery power system, which includes: a fuel tank 101, a blower 102, a first heat exchanger 103, a second heat exchanger 104, a fuel cell stack 105, a DC-DC converter 106, a combustion chamber 107, and a lithium battery 108; the fuel tank 101 is used to store fuel gas and water (H2O).

[0034] The fuel tank 101, the first heat exchanger 103 and the anode side of the fuel cell stack 105 are connected in sequence, the blower 102, the second heat exchanger 104 and the cathode side of the fuel cell stack 105 are connected in sequence, and the reaction gas output end of the fuel cell stack 105 is connected to the combustion chamber 107.

[0035] The fuel cell stack 105 is also electrically connected to a marine busbar for supplying power to the marine propulsion system 109 via the DC-DC converter 106.

[0036] It is understood that the fuel tank 101, blower 102, first heat exchanger 103, second heat exchanger 104, fuel cell stack 105, DC-DC converter 106, and combustion chamber 107 provided by the present invention together constitute a solid oxide fuel cell (SOFC). The fuel tank 101 delivers fuel to the first heat exchanger 103, which heats the fuel and then delivers it to the anode of the fuel cell stack 105. The blower 102 delivers air to the second heat exchanger 104, which heats the air and then delivers it to the cathode of the fuel cell stack 105. The fuel and air react in the fuel cell stack 105 to generate electrical energy. The electrical energy is converted by the DC-DC converter 106 and then transmitted to the marine bus, which can be a DC bus.

[0037] The marine busbar is electrically connected to a lithium battery 108 and a marine propulsion system 109. The electrical energy generated by the reaction in the fuel cell stack 105 supplies power to the marine propulsion system 109 through the marine busbar to ensure its operation. Simultaneously, the electrical energy generated by the reaction in the fuel cell stack 105 can also be used to charge the lithium battery 108. In pure electric mode, the fuel cell stack 105 stops working, and the lithium battery 108 supplies power to the marine propulsion system 109. When the state of charge (SOC) of the lithium battery 108 is low, it can be powered by the fuel cell stack 105 to ensure its lifespan. The electrical energy generated by the fuel cell stack 105 also provides sufficient power to the marine propulsion system 109, thereby ensuring the ship's sailing range.

[0038] In some embodiments, both the first heat exchanger 103 and the second heat exchanger 104 are plate heat exchangers.

[0039] As is understandable, a plate heat exchanger is a high-efficiency heat exchanger composed of a series of metal plates with a certain corrugated shape stacked together. Thin rectangular channels are formed between the plates, through which heat exchange occurs. Plate heat exchangers are ideal devices for liquid-liquid and liquid-vapor heat exchange. They feature high heat exchange efficiency, low heat loss, compact and lightweight structure, small footprint, wide application, and long service life. Under the same pressure loss conditions, their heat transfer coefficient is 3-5 times higher than that of a tubular heat exchanger, their footprint is one-third that of a tubular heat exchanger, and their heat recovery rate can reach over 90%.

[0040] Plate heat exchangers are mainly classified into two types: frame type (detachable) and brazed type. The plate types are mainly herringbone corrugated plates, horizontal straight corrugated plates, and nodular plates.

[0041] In some embodiments, the number of fuel cell stacks 105 is at least two, and each fuel cell stack 105 includes a plurality of fuel cells connected in parallel.

[0042] It is understandable that the number of fuel cell stacks 105 can be two, three, or four, with multiple fuel cell stacks 105 connected in parallel, and each fuel cell stack 105 includes multiple fuel cells connected in parallel, which are fuel cells.

[0043] The first heat exchanger 103 is connected to the anode inlet of each cell in the fuel cell stack 105, and the second heat exchanger 104 is connected to the cathode inlet of each cell in the fuel cell stack 105. The fuel delivered by the first heat exchanger 103 and the air delivered by the second heat exchanger 104 react in the fuel cell to generate electricity.

[0044] In some embodiments, the number of DC converters 106 is the same as the number of fuel cell stacks 105, and each fuel cell stack 105 is electrically connected to the marine bus via a corresponding DC converter 106.

[0045] It is understandable that the DC-DC converter 106 transforms one type of DC power supply into another type of DC power supply with different output characteristics. Here, the DC-DC converter 106 specifically refers to the DC-DC converter 106. The marine bus is a DC bus, and the electrical energy generated by the fuel cell stack 105 is also DC. However, the voltage and current output by the fuel cell stack 105 may not meet the requirements of the marine bus. Therefore, it is necessary to convert the electrical energy output by the fuel cell stack 105 to meet the voltage and current requirements of the marine bus.

[0046] In some embodiments, the exhaust gas outlet of the combustion chamber 107 is connected to the first heat exchanger 103, and the first heat exchanger 103 is also connected to the second heat exchanger 104.

[0047] Understandably, the exhaust gas from combustion chamber 107 carries heat, which can be transferred to the first heat exchanger 103 for heat exchange to heat the fuel output from the fuel tank; similarly, the exhaust gas from combustion chamber 107 can also be transferred to the second heat exchanger 104 for heat exchange to heat the air supplied by blower 102; when the heated fuel and air react in fuel cell stack 105, the reaction efficiency can be improved, thereby improving the efficiency of power output.

[0048] In some embodiments, the marine battery power system further includes: a first diverter valve 110 and a second diverter valve 111;

[0049] The first heat exchanger 103 is connected to the anode side of different fuel cells in the fuel cell stack 105 through the first diversion valve 110, and the second heat exchanger 104 is connected to the cathode side of different fuel cells in the fuel cell stack 105 through the second diversion valve 111.

[0050] It is understandable that a flow divider valve, also known as a speed synchronization valve, is a general term for flow divider valves, flow combiner valves, one-way flow divider valves, one-way flow combiner valves, and proportional flow divider valves in hydraulic systems. Synchronization valves are mainly used in dual-cylinder and multi-cylinder synchronous control hydraulic systems. While there are many methods to achieve synchronized motion, the synchronous control hydraulic system using a flow divider / combiner valve-synchronization valve has many advantages, including simple structure, low cost, ease of manufacturing, and high reliability. Therefore, synchronization valves are widely used in hydraulic systems. The synchronization of a flow divider / combiner valve is speed synchronization; when two or more cylinders are subjected to different loads, the flow divider / combiner valve can still ensure their synchronized motion. In this embodiment, the flow divider valve can be one of a fixed flow divider / combiner valve, a self-adjusting flow divider / combiner valve, or an adjustable flow divider / combiner valve.

[0051] The first diversion valve 110 can deliver fuel from the fuel tank 101 to each cell of the fuel cell stack 105 in a proportional manner, and the second diversion valve 111 can deliver air to each cell of the fuel cell stack 105 in a proportional manner, ensuring that the proportion of reaction materials in each cell of the fuel cell stack 105 is appropriate and improving the efficiency of the fuel cell stack 105 in generating electrical energy.

[0052] In some embodiments, in the marine battery power system provided by the present invention, fuel tank 101 stores fuel gas and water. After being preheated by a plate heat exchanger, the fuel gas enters the anode side of the parallel array of four fuel cells through a diversion valve. Air passes through a blower 102, is preheated by a plate heat exchanger, and then enters the cathode side of the parallel array of four fuel cells through a diversion valve. The anode and cathode gases, after reacting in the fuel cell stack 105, converge into the combustion chamber 107 for combustion. The high-temperature flue gas after combustion exchanges heat with two plate heat exchangers. After reaching the operating temperature, the series-parallel array of four fuel cells is converted by a DC / DC converter 106 and connected in parallel with the lithium battery 108 to the DC bus of the all-electric propulsion ship, jointly supplying power to the marine propulsion system 109 in the form of a hybrid power system.

[0053] When the combined propulsion system is in pure electric mode, the lithium battery 108 provides the main power for the ship's electric propulsion load. The state of charge of the lithium battery 108 is monitored. If the state of charge of the lithium battery 108 is lower than 30%, the solid oxide fuel cell equipment is started to charge the lithium battery 108 and serve as auxiliary power. When the combined propulsion system is in hybrid mode, the solid oxide fuel cell equipment provides the main power for the ship's electric propulsion load, while the energy required for the ship's power load to change is absorbed or released by the lithium battery 108.

[0054] To address the above workflow, models of each component are constructed, and considering the failure degradation mechanism, a multi-scale model of the solid oxide fuel cell system is built. This model covers the system's operation under multiple modes, including normal, fault, and performance degradation. Dynamic and static analyses are conducted to determine the optimal operating mode and optimal operating trajectory for high energy efficiency and long lifespan of the system.

[0055] Based on the power command issued by the system, the optimal power of each module at this time is calculated based on the system's multi-scale model, and the power of each stack 105 module is dynamically allocated to achieve optimal system control.

[0056] In summary, the present invention provides a marine battery power system comprising: a fuel tank 101, a blower 102, a first heat exchanger 103, a second heat exchanger 104, a fuel cell stack 105, a DC-DC converter 106, a combustion chamber 107, and a lithium battery 108; the anode sides of the fuel tank 101, the first heat exchanger 103, and the fuel cell stack 105 are sequentially connected, the cathode sides of the blower 102, the second heat exchanger 104, and the fuel cell stack 105 are sequentially connected, and the reaction gas output terminal of the fuel cell stack 105 is connected to the combustion chamber 107; the fuel cell stack 105 is also electrically connected to a marine busbar for supplying power to a marine propulsion system 109 via the DC-DC converter 106.

[0057] The marine battery power system provided by this invention comprises a solid oxide fuel cell structure consisting of a fuel tank 101, a blower 102, a first heat exchanger 103, a second heat exchanger 104, a fuel cell stack 105, a DC-DC converter 106, and a combustion chamber 107. This solid oxide fuel cell, together with a lithium battery 108, forms a hybrid power battery to supply power to the marine propulsion system 109. The fuel tank 101 can store sufficient fuel. Through the combination of the solid oxide fuel cell structure and the lithium battery 108, it can provide sufficient electrical energy to aid in long-distance ocean voyages. Furthermore, when the state of charge of the lithium battery 108 is low, the solid oxide fuel cell structure can charge the lithium battery 108, preventing over-discharge and shortening its lifespan. Therefore, the marine battery power system provided by this invention can solve the technical problems of existing marine electrical systems being unable to adapt to long-distance ocean voyages and having a short service life.

[0058] Furthermore, the marine battery power system provided by this invention can achieve the following technical effects:

[0059] Online intelligent power prediction control based on a hybrid power system of solid oxide fuel cell and lithium battery 108 determines the optimal switching trajectory between solid oxide fuel cell and lithium battery 108, balances the performance degradation between multiple stack 105 modules, and rationally allocates the power among each stack 105 module to ensure optimal fuel utilization and conversion efficiency.

[0060] The present invention also provides a control method for a marine battery power system, wherein the method is applied to any of the above-described marine battery power systems, such as... Figure 2 As shown, the method includes:

[0061] S201. When the marine battery power system is in pure electric mode, control the lithium battery 108 to output electrical energy.

[0062] S202, when the state of charge of the lithium battery 108 is lower than a preset threshold, or when the marine battery power system is in hybrid mode, the fuel tank 101 is controlled to deliver fuel to the fuel cell stack 105 for combustion, so as to output electrical energy through the fuel cell stack 105.

[0063] It is understood that the marine battery power system provided by the present invention has two working modes: a pure electric mode and a hybrid mode. In the pure electric mode, the lithium battery 108 supplies power alone, while in the hybrid mode, the battery stack 105 and the lithium battery 108 provide power in combination.

[0064] In this embodiment, the lithium battery 108, fuel tank, and fuel cell stack 105 can be controlled by the marine battery management system to control the lithium battery 108 to start working and output electrical energy, or to control the fuel tank to output fuel and control the fuel cell stack 105 to start working.

[0065] When the state of charge of the lithium battery 108 is lower than a preset threshold, the fuel tank 101 is controlled to deliver fuel to the fuel cell stack 105 for combustion. The fuel cell stack 105 outputs electrical energy, reducing the load on the lithium battery 108 and extending its service life. Furthermore, by using the fuel cell stack 105 and the lithium battery 108 together for power supply, the ship's sailing distance can be extended.

[0066] In some embodiments, such as Figure 3 As shown, the control method for the marine battery power system further includes:

[0067] S301. Construct a multi-scale model corresponding to the marine battery power system;

[0068] S302. Determine the optimal power corresponding to different fuel cell stacks 105 based on the multi-scale model, and control the working state of the fuel cell stack 105 based on the optimal power.

[0069] It is understandable that "multi-scale" in multi-scale models refers to sampling signals at different granularities; multi-scale models include: pyramid models, dilated convolutional network models, and pyramid convolutional neural network models.

[0070] Among them, the pyramid module can be a feature pyramid, which is a pyramid operation at the feature scale. It is implemented by fusing top-down and bottom-up feature maps.

[0071] In some embodiments, the principle diagram of the method provided by the present invention for optimal energy allocation based on a multi-scale model is shown below. Figure 4 As shown, optimal energy allocation determines optimal power, referencing... Figure 4A basic model of a solid oxide fuel cell, DC / DC converter, load, and battery is constructed, based on the actual discharge power P of the solid oxide fuel cell. FC and fuel utilization rate FU FC By considering the nonlinear relationship and combining experimental data to control the error between the model and the experimental data to within 5%, the multimodal parameters Ψ of each fuel cell can be obtained. FC ;P load To meet the actual load requirements and ensure the safe operation of the battery, its operating parameters should be constrained to extend its lifespan. Firstly, the battery's State of Charge (SOC) should meet a minimum constraint of 20% and a maximum of 95%. Secondly, the battery's output power P... Bat It should also satisfy the maximum and minimum value parameter constraints; at the same time, the actual output of the system, i.e., P... Bat With P FC The sum should meet the actual load requirement P. load Based on the constructed multimodal parameter Ψ FC and P FC The actual power output P of each fuel cell stack can be solved based on the optimal energy allocation of the multi-scale model. ref FC At what power setting can the system achieve its maximum fuel utilization rate? This power setpoint is then sent to the controller to control the DC / DC converter to apply load, thereby achieving optimal energy allocation within the system, i.e., optimal power.

[0072] The above provides a detailed description of the marine battery power system and its control method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A marine battery power system, characterized in that, include: Fuel tank, blower, first heat exchanger, second heat exchanger, fuel cell stack, DC-DC converter, combustion chamber, and lithium battery; The fuel tank, the first heat exchanger, and the anode side of the fuel cell stack are connected in sequence. The blower, the second heat exchanger, and the cathode side of the fuel cell stack are connected in sequence. The reaction gas output end of the fuel cell stack is connected to the combustion chamber. The fuel cell stack is also electrically connected to a marine busbar for powering the marine propulsion system via the DC-DC converter. In pure electric mode, the fuel cell stack stops working, and the lithium battery powers the marine propulsion system. When the lithium battery has a low state of charge, the fuel cell stack provides power to ensure the lifespan of the lithium battery.

2. The marine battery power system according to claim 1, characterized in that, Both the first heat exchanger and the second heat exchanger are plate heat exchangers.

3. The marine battery power system according to claim 1, characterized in that, The fuel compartment is used to store fuel gas and water.

4. The marine battery power system according to claim 1, characterized in that, The number of fuel cell stacks is at least two, and each stack includes multiple fuel cells connected in parallel.

5. The marine battery power system according to claim 4, characterized in that, The number of DC converters is the same as the number of fuel cell stacks, and each fuel cell stack is electrically connected to the marine bus via a corresponding DC converter.

6. The marine battery power system according to claim 1, characterized in that, The exhaust gas outlet of the combustion chamber is connected to the first heat exchanger.

7. The marine battery power system according to claim 6, characterized in that, The first heat exchanger is also connected to the second heat exchanger.

8. The marine battery power system according to any one of claims 1-7, characterized in that, Also includes: First diverter valve and second diverter valve; The first heat exchanger is connected to the anode side of different fuel cells in the stack via the first diversion valve, and the second heat exchanger is connected to the cathode side of different fuel cells in the stack via the second diversion valve.

9. A control method for a marine battery power system, characterized in that, The method is applied to the marine battery power system according to any one of claims 1-8, and the method includes: When the marine battery power system is in pure electric mode, control the output of electrical energy from the lithium battery; When the state of charge of the lithium battery is below a preset threshold, or when the marine battery power system is in hybrid mode, the fuel tank is controlled to deliver fuel to the fuel cell stack for combustion, so as to output electrical energy through the fuel cell stack.

10. The control method for a marine battery power system according to claim 9, characterized in that, Also includes: Construct a multi-scale model corresponding to the marine battery power system; The optimal power corresponding to different fuel cell stacks is determined based on the multi-scale model, and the operating state of the fuel cell stack is controlled based on the optimal power.

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