Off-grid and grid-connected hydrogen-electricity hybrid energy storage system

Abstract

The invention relates to the technical field of new energy, in particular to an off-grid and grid-connected dual-purpose hydrogen-electricity hybrid energy storage system, which comprises a DC-DC power supply controller, an electrolytic hydrogen production device, a lithium battery device, a logic control circuit and a renewable energy source-based power generation device, the DC-DC power supply controller is electrically connected with the power generation device through a direct current bus; the logic control circuit is electrically connected with the DC-DC power supply controller, and the lithium battery device and the electrolytic hydrogen production device are connected to the logic control circuit; a lithium battery device energy storage device and an electrolytic hydrogen production device are integrated, a plurality of switchable working modes are formed through a logic control circuit, a multi-path and self-adaptive absorption solution is provided for fluctuating renewable energy sources, the problem that energy storage and hydrogen production are independently set in a traditional scheme is solved, and the energy storage and hydrogen production efficiency is improved. Therefore, the system can select an energy conversion form according to power generation conditions, power and hydrogen demands and environmental factors, or adopts a series coupling form to improve the energy utilization degree of freedom and efficiency of the off-grid system.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a hydrogen-electric hybrid energy storage system that can be used both off-grid and on-grid. Background Technology

[0002] With the advancement of the "dual carbon" target, distributed renewable energy sources, represented by photovoltaics and wind power, have been widely applied. However, their power generation output exhibits significant intermittency, randomness, and volatility. In off-grid or remote areas, the instability of these energy sources poses a severe challenge to reliable power supply. Existing technologies commonly include off-grid lithium battery energy storage systems and independent water electrolysis hydrogen production systems, but both have significant technical limitations. Firstly, while off-grid lithium battery energy storage systems offer fast response times, their limited cost and volumetric energy density typically restrict their energy storage to short-term durations of only a few hours. In off-grid scenarios with drastic photovoltaic fluctuations, lithium batteries require frequent high-rate charging and discharging to smooth out power fluctuations. This not only accelerates battery capacity degradation and shortens lifespan but also poses a significant risk of thermal runaway. Furthermore, relying solely on lithium batteries cannot achieve long-term energy storage across days and seasons, resulting in a substantial waste of excess photovoltaic power and overall low energy utilization.

[0003] Secondly, independent water electrolysis hydrogen production systems, especially proton exchange membrane (PEM) electrolyzers with fast response times, are considered an effective way to utilize surplus renewable energy and produce green hydrogen. However, PEM electrolyzers have high requirements for the stability of the input power supply. If directly coupled with a highly volatile photovoltaic power source, the PEM electrolyzer will operate under drastically fluctuating power for extended periods, even with frequent start-ups and shutdowns and low-load conditions. This will cause the membrane electrodes to endure repeated mechanical stress and thermal shock, accelerating their aging and performance degradation, and potentially leading to hydrogen-oxygen cross-contamination safety hazards under low-load conditions due to increased gas permeation. Furthermore, traditional hydrogen production solutions typically require high-pressure hydrogen storage tanks and transportation facilities, posing risks of hydrogen storage leakage and high transportation costs in user-side or mobile application scenarios.

[0004] Furthermore, existing technologies that attempt to simply connect photovoltaics, lithium batteries, and electrolyzers in parallel or manage them independently fail to fundamentally solve the problems of efficient energy flow coordination and optimized equipment lifespan. If fluctuating photovoltaic power is used to charge the lithium battery first through a rectifier, and then the lithium battery discharges to drive the electrolyzer, there is an efficiency loss due to two energy conversions. If the photovoltaic power is directly connected to the electrolyzer, there is a lack of effective buffering for power fluctuations, which impairs the electrolyzer's lifespan.

[0005] In summary, there is an urgent need for an integrated energy solution that can achieve long-term energy storage, high energy density, on-demand production, safety and reliability, and intelligent adaptation to renewable energy fluctuations, while also considering the lifespan of energy storage components and hydrogen production equipment. Existing technologies have not yet effectively integrated and resolved these multiple challenges. Therefore, this invention proposes an innovative off-grid and grid-connected hydrogen-electric hybrid energy storage system and its collaborative control strategy. Summary of the Invention

[0006] The main objective of this invention is to provide a hydrogen-electric hybrid energy storage system that can be used both off-grid and on-grid, so as to achieve long-term energy storage, high energy density, on-demand production and use, safety and reliability, and intelligent adaptation to renewable energy fluctuations, while taking into account the service life of energy storage components and hydrogen production equipment.

[0007] To achieve the above objectives, the present invention provides a hydrogen-electric hybrid energy storage system, which includes: a DC-DC power controller, an electrolysis hydrogen production device, a lithium battery device, a logic control circuit, and a power generation device based on renewable energy. The DC-DC power controller is electrically connected to the power generation device via a DC bus; the logic control circuit is electrically connected to the DC-DC power controller, and the lithium battery device and the electrolytic hydrogen production device are connected to the logic control circuit. The logic control circuit is configured to: based on the output power characteristics of the power generation device, control the lithium battery device to be electrically connected to the DC bus via the DC-DC power controller for charging or discharging; or control the electrolytic hydrogen production device to be electrically connected to the DC bus via the DC-DC power controller for electrolytic hydrogen production; or control the lithium battery device and the electrolytic hydrogen production device to be connected in series and then jointly electrically connected to the DC bus via the DC-DC power controller.

[0008] Optionally, the power generation device is a distributed photovoltaic power generation device, or the power generation device is a wind power generation device.

[0009] Optionally, the logic control circuit includes a first switching control mechanism disposed between the lithium battery device and the DC-DC power controller, a second switching control mechanism disposed between the electrolytic hydrogen production device and the DC-DC power controller, and a third switching control mechanism disposed between the lithium battery device and the electrolytic hydrogen production device.

[0010] Optionally, the power generation device is a distributed photovoltaic power generation device; The logic control circuit is configured as follows: When the light intensity is at a high or medium level and stable: During the start-up and shutdown phases of the system, the lithium battery device and the electrolysis hydrogen production device are connected in series and electrically connected to the DC bus via the DC-DC power controller. After the system starts and stops, the lithium battery device is charged by connecting it to the DC bus via the DC-DC power controller. At the same time, the lithium battery device is disconnected from the electrolytic hydrogen production device and the electrolytic hydrogen production device is disconnected from the DC-DC power controller. After the lithium battery device reaches a first preset power level, the lithium battery device and the electrolytic hydrogen production device are connected in series and electrically connected to the DC bus via the DC-DC power controller. When the light intensity is at a high level and fluctuates greatly: The lithium battery device is connected in series with the electrolytic hydrogen production device, and both are electrically connected to the DC bus via the DC-DC power controller. After the lithium battery device reaches the second preset power level, the series connection between the lithium battery device and the electrolytic hydrogen production device is disconnected, and the electrical connection between the lithium battery device and the DC-DC power controller is disconnected. At the same time, the electrolytic hydrogen production device is controlled to be electrically connected to the DC bus via the DC-DC power controller to perform electrolytic hydrogen production. When the light intensity is at a medium level and the light intensity fluctuation is downward, or when the lithium battery device is fully charged: The electrolytic hydrogen production device is controlled to be electrically connected to the DC bus via the DC-DC power controller to perform electrolytic hydrogen production. When the light level is low and the light intensity is stable: The lithium battery device is only controlled to be charged by electrically connecting the lithium battery device to the DC bus via the DC-DC power controller. Among them: when the real-time light intensity reaches 80% or above of the preset rated light intensity, it is defined as strong light level; when the real-time light intensity reaches 50% to 80% of the preset rated light intensity, it is defined as medium light level; when the real-time light intensity is less than 50% of the preset rated light intensity, it is defined as weak light level; stable light intensity is defined as the change in current per second does not exceed 5% of the current in the previous second; if the change in current per second exceeds 1% in any time exceeding 30 seconds, it is considered light intensity fluctuation; a downward change in current exceeding 1% is considered downward light intensity fluctuation.

[0011] Optionally, the logic control circuit further includes a light intensity sensor; the light intensity sensor is used to monitor light intensity.

[0012] Optionally, the first preset charge is 90% of the rated capacity of the lithium battery device.

[0013] Optionally, the second preset charge is 100% of the rated capacity of the lithium battery device.

[0014] Optionally, the DC-DC power controller, the lithium battery device, and the logic control circuit are all located inside the housing.

[0015] Optionally, the electrolytic hydrogen production device is fixedly installed on the outer wall of the tank.

[0016] Optionally, the front panel of the enclosure is provided with an openable and closable door.

[0017] The beneficial effects of this invention are: This invention provides a hydrogen-electric hybrid energy storage system, comprising: a DC-DC power controller, an electrolysis hydrogen production device, a lithium battery device, a logic control circuit, and a renewable energy-based power generation device; the DC-DC power controller is electrically connected to the power generation device via a DC bus; the logic control circuit is electrically connected to the DC-DC power controller, and the lithium battery device and the electrolysis hydrogen production device are connected to the logic control circuit; the logic control circuit is configured to: based on the output power characteristics of the power generation device, control the lithium battery device to be electrically connected to the DC bus via the DC-DC power controller for charging or discharging; or control the electrolysis hydrogen production device to be electrically connected to the DC bus via the DC-DC power controller for electrolysis hydrogen production; or control the lithium battery device and the electrolysis hydrogen production device to be connected in series and then jointly connected to the DC bus via the DC-DC power controller.

[0018] By integrating lithium battery energy storage and electrolysis hydrogen production devices, and forming multiple switchable basic operating modes through logic control circuits, a multi-path, adaptive consumption solution for fluctuating renewable energy is provided. This breaks the problem of independent energy storage and hydrogen production in traditional solutions, enabling the system to select the energy conversion form according to power generation status, electricity and hydrogen demand, and environmental conditions. Alternatively, a series coupling method can be used to improve the energy utilization freedom and overall efficiency of the off-grid system. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A schematic diagram of a hydrogen-electric hybrid energy storage system provided in an embodiment of the present invention; Figure 2 This is a structural diagram of a hydrogen-electric hybrid energy storage system provided in an embodiment of the present invention.

[0021] Icons: 100 - Power generation unit; 200 - Electrolysis hydrogen production unit; 300 - Lithium battery unit; 410 - First switching control mechanism; 420 - Second switching control mechanism; 500 - Housing; 600 - DC-DC power controller. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] This invention provides a hydrogen-electric hybrid energy storage system that can be used both off-grid and on-grid, such as... Figure 1 and Figure 2 The system includes: a DC-DC power controller 600, an electrolytic hydrogen production device 200, a lithium battery device 300, a logic control circuit, and a renewable energy-based power generation device 100. The DC-DC power controller 600 is electrically connected to the power generation device 100 via a DC bus. The logic control circuit is electrically connected to the DC-DC power controller 600. The lithium battery device 300 and the electrolytic hydrogen production device 200 are connected to the logic control circuit. The hydrogen produced by the electrolytic hydrogen production device 200 can also be supplied to the hydrogen power generation device for power generation. The hydrogen power generation device can be part of this system; that is, the system in this application also includes a hydrogen power generation device for receiving hydrogen produced by the electrolytic hydrogen production device 200 for power generation. Alternatively, the aforementioned hydrogen power generation device can be an optional external device, relatively independent of this system. During use, hydrogen generated by the electrolysis hydrogen production device 200 can be selectively delivered to the hydrogen power generation device according to actual conditions. The logic control circuit is configured to: control the lithium battery device 300 to be electrically connected to the DC bus via the DC-DC power controller 600 for charging or discharging, based on the output power characteristics of the power generation device 100; or control the electrolysis hydrogen production device 200 to be electrically connected to the DC bus via the DC-DC power controller 600 for electrolysis hydrogen production; or control the lithium battery device 300 and the electrolysis hydrogen production device 200 to be connected together via the DC-DC power controller 600 to the DC bus.

[0030] The hydrogen-electric hybrid energy storage system provided in this embodiment of the invention, which can be used both off-grid and on-grid, has a logic control circuit configured to achieve multiple basic operating modes. In the first mode, the corresponding switching control mechanism is controlled so that the lithium battery device 300 forms a closed loop with the DC bus via the DC-DC power controller 600, and the energy of the power generation device 100 is used to charge the lithium battery. In the second mode, the switching control mechanism is controlled so that the electrolysis hydrogen production device 200 is connected to the DC bus via the DC-DC power controller 600, and the energy of the power generation device 100 is directly used for water electrolysis to produce hydrogen. In the third mode, the logic control circuit controls the lithium battery device 300 and the electrolysis hydrogen production device 200 to be electrically connected in series to form a single load, which is then connected to the DC bus via the DC-DC power controller 600. In this mode, the same current flows sequentially through the lithium battery and the electrolyzer, achieving simultaneous charging and hydrogen production. In some optional embodiments, the first and second modes can also be performed simultaneously, in which case the lithium battery device 300 and the electrolysis hydrogen production device 200 are connected in parallel.

[0031] In this embodiment, by integrating a lithium battery device 300 for energy storage and an electrolysis hydrogen production device 200, and by forming multiple switchable basic operating modes through a logic control circuit, a multi-path, adaptive consumption solution for fluctuating renewable energy is provided. This breaks the problem of independent setting of energy storage and hydrogen production in traditional solutions, enabling the system to select the energy conversion form according to the power generation status, electricity and hydrogen demand, and environmental conditions. Alternatively, a series coupling form can be used to improve the energy utilization freedom and overall efficiency of the off-grid system.

[0032] In optional embodiments of this application, the power generation device 100 is a distributed photovoltaic power generation device, or the power generation device 100 is a wind power generation device.

[0033] In optional embodiments of this application, the logic control circuit includes a first switching control mechanism 410 disposed between the lithium battery device 300 and the DC-DC power controller 600, a second switching control mechanism 420 disposed between the electrolytic hydrogen production device 200 and the DC-DC power controller 600, and a third switching control mechanism disposed between the lithium battery device 300 and the electrolytic hydrogen production device 200.

[0034] In this embodiment, when only the first switching control mechanism 410 is closed and the second switching control mechanism 420 and the third switching control mechanism are disconnected, the lithium battery device 300 is connected to the system alone; when only the second switching control mechanism 420 is closed and the first switching control mechanism 410 and the third switching control mechanism are disconnected, the electrolytic hydrogen production device 200 is connected to the system alone; when the third switching control mechanism is closed and either the first switching control mechanism 410 or the second switching control mechanism 420 is closed, the lithium battery device 300 and the electrolytic hydrogen production device 200 connected in series are connected to the system as a whole, thereby entering a collaborative working mode.

[0035] Optionally, in this embodiment, the first switching control mechanism 410, the second switching control mechanism 420, and the third switching control mechanism may be switches, bidirectional circuit breakers, or any controllable logic switching circuit.

[0036] In an optional embodiment of this application, the power generation device 100 is a distributed photovoltaic power generation device; the logic control circuit is configured as follows: when the light intensity is at a strong or medium level and the light intensity is stable: during the system start-up and shutdown phase, the lithium battery device 300 and the electrolytic hydrogen production device 200 are connected in series and electrically connected to the DC bus via the DC-DC power controller 600; after the system start-up and shutdown are completed, the lithium battery device 300 is charged by being electrically connected to the DC bus via the DC-DC power controller 600. Disconnect the lithium battery device 300 from the electrolysis hydrogen production device 200 in series, and disconnect the electrolysis hydrogen production device 200 from the DC-DC power controller; after the lithium battery device 300 reaches a first preset charge level, control the lithium battery device 300 and the electrolysis hydrogen production device 200 to be connected in series and electrically connected to the DC bus via the DC-DC power controller 600; when the light intensity is high and fluctuates greatly: control the lithium battery device 300 and the electrolysis hydrogen production device 200 to be connected in series and electrically connected to the DC bus via the DC-DC power controller 600. 0 is electrically connected to the DC bus; after the lithium battery device 300 reaches the second preset charge, the series connection between the lithium battery device 300 and the electrolysis hydrogen production device 200 is disconnected, and the electrical connection between the lithium battery device 300 and the DC-DC power controller 600 is also disconnected. Simultaneously, the electrolysis hydrogen production device 200 is controlled to be electrically connected to the DC bus via the DC-DC power controller 600 to perform electrolysis hydrogen production; when the light level is medium and the light intensity fluctuation is downward, or when the lithium battery device 300 is fully charged: only the electrolysis hydrogen production device 200 is controlled. The system 00 is electrically connected to the DC bus via the DC-DC power controller 600 for hydrogen electrolysis. When the light intensity is low and stable, only the lithium battery device 300 is connected to the DC bus via the DC-DC power controller 600 to charge it. Specifically: a real-time light intensity of 80% or higher of the preset rated light intensity is defined as a strong light level; a real-time light intensity between 50% and 80% of the preset rated light intensity is defined as a medium light level; and a real-time light intensity lower than 50% of the preset rated light intensity is defined as a low light level. Stable light intensity is defined as a change in current per second not exceeding 5% of the current in the previous second. Within any continuous 30 seconds of operation, any change in current per second exceeding 5% of the previous change is considered a light intensity fluctuation; a downward change in current exceeding 1% is considered a downward light intensity fluctuation.

[0037] In this embodiment, the system first assesses the real-time light intensity and its stability by monitoring the DC bus voltage and current or by equipping a dedicated light intensity sensor. The light intensity level is quantified as a percentage of the real-time light intensity relative to a preset rated light intensity (such as the light intensity under standard noon test conditions): 80% or higher is considered strong light, 50% to 80% is medium light, and below 50% is weak light. Light intensity stability is determined by analyzing the frequency and amplitude of light intensity changes. Light intensity stability is defined as a change in current per second not exceeding 1% of the preset rated current and maintained for more than thirty seconds. Within these thirty seconds, any change in current per second exceeding 1% is considered a light intensity fluctuation; a downward change in current exceeding 1% is considered a downward light intensity fluctuation.

[0038] Based on this, when the light intensity is strong or moderate and stable, the system first connects the lithium battery device 300 and the electrolysis hydrogen production device 200 in series during startup or shutdown, utilizing their common impedance to smooth out initial power fluctuations such as startup shocks. After stabilization, the system switches to charging only the lithium battery device 300. When the lithium battery device 300 reaches 90% of its rated capacity, the system switches back to the series operation mode to achieve stable power generation and hydrogen production. When the light intensity is strong but highly volatile, the system directly enters the series operation mode and instructs the DC-DC power controller 600 to perform adaptive power distribution, dynamically adjusting the current distribution between battery charging and electrolysis hydrogen production until the battery is fully charged. After the battery is fully charged, the system disconnects the lithium battery device 300, leaving only the electrolysis hydrogen production device 200 operating. When the light intensity is moderate and decreasing, or when the lithium battery device 300 is fully charged regardless of the lighting conditions, the system uses the electrolysis hydrogen production mode only. When the light level is low and stable, the system adopts a lithium battery-only 300 charging mode and charges slowly at a lower power to protect the battery.

[0039] In this embodiment, by determining both light intensity level and stability, the logic control circuit identifies the operating conditions of the distributed photovoltaic power generation device and switches the working mode accordingly, so that energy utilization reaches the optimal state under each operating condition. When the light is strong and stable, energy storage and hydrogen production are balanced; when the light fluctuates, the equipment is protected first and the energy is absorbed in a coordinated manner; when the light fluctuates moderately or the battery is fully charged, hydrogen production is prioritized; and when the light is weak, energy storage is prioritized, thereby maximizing energy utilization in all weather conditions and under all operating conditions.

[0040] Meanwhile, under conditions of large light intensity fluctuations, the continuous series operation mode enables the lithium battery device 300 to always play a role in buffering fluctuations, preventing the electrolytic hydrogen production device 200 from directly bearing severe fluctuation currents and delaying the degradation of the membrane electrode. The series shock resistance during start-up and shutdown reduces the damage to the equipment caused by voltage spikes during start-up and shutdown, and extends the overall service life of the system.

[0041] Furthermore, the electrolysis hydrogen production unit 200 does not need to be started under low light conditions (hydrogen production efficiency is low at low power), and there is no need to continue charging the lithium battery when it is fully charged, significantly improving the system's operating efficiency and reducing unnecessary energy consumption. This control strategy perfectly matches the output characteristics of distributed photovoltaic power generation, greatly improving the system's practicality and reliability in off-grid photovoltaic scenarios.

[0042] In an optional embodiment of this application, the logic control circuit further includes a light intensity sensor; the light intensity sensor is used to monitor light intensity.

[0043] In this embodiment, by adding a light intensity sensor, the illumination status can be obtained directly and accurately. Compared with indirectly inferring the illumination status through DC bus electrical parameters, this method has the advantages of lower latency, stronger anti-interference capability, and more accurate judgment.

[0044] In other alternative implementations, environmental sensors such as wind sensors and temperature sensors can be added to replace the aforementioned light intensity sensor, depending on the actual usage. Alternatively, the switching between energy storage and hydrogen production power can be maximized by monitoring internal components, such as battery capacity, and hydrogen usage requirements.

[0045] In optional embodiments of this application, the enclosure 500 is also included; the DC-DC power controller 600, the lithium battery device 300, and the logic control circuit are all disposed inside the enclosure 500.

[0046] In an optional embodiment of this application, the electrolytic hydrogen production device is fixedly installed on the outer wall of the housing 500.

[0047] In an optional embodiment of this application, the front panel of the housing 500 is provided with an openable and closable door.

[0048] In this embodiment, the DC-DC power controller 600, lithium battery device 300, and logic control circuit are integrated and installed inside the housing 500. The electrolytic hydrogen production device 200 is fixedly installed on the outer wall of the housing 500, thereby improving safety performance. A door is provided on the front panel of the housing 500 for opening or closing the housing 500, thereby facilitating the inspection and maintenance of the components inside the housing 500. Furthermore, the system has a high degree of integration and is also convenient for carrying and transporting.

[0049] The hydrogen-electric hybrid energy storage system provided in this application, which can be used both off-grid and on-grid, effectively addresses the technical problem of slow response of lithium batteries and voltage spikes in the electrolysis hydrogen production unit 200 when power fluctuations occur in distributed photovoltaic power generation devices. This is achieved by using the physical characteristics of the lithium battery device 300 to directly absorb and store power. When power fluctuations occur in distributed photovoltaic power generation devices, the logic control circuit adjusts the current output of the lithium battery device 300 and the DC-DC power controller 600 to smooth the DC bus voltage. The remaining stable power is then supplied to the electrolysis hydrogen production unit 200. To absorb high-frequency fluctuations, when the distributed photovoltaic power generation device generates a peak current, the internal resistance and electrochemical polarization characteristics of the lithium battery device 300 naturally smooth the current rise through the hydrogen electrolysis device 200, absorbing the high-frequency fluctuations. This significantly reduces the mechanical stress and thermal shock on the proton exchange membrane of the hydrogen electrolysis device 200, extending its lifespan. Furthermore, the series connection between the hydrogen electrolysis device 200 and the lithium battery device 300 also reduces the impact of high fluctuations on the lifespan of the lithium battery device 300, improving its safety and lifespan. Simultaneously, in this application, the same current accomplishes two tasks: storing electrochemical energy in the lithium battery device 300 and generating hydrogen energy in the hydrogen electrolysis device 200. Moreover, when hydrogen production is needed, the lithium battery device 300 can supply power to the hydrogen electrolysis device 200 independently or simultaneously with an external power source. Therefore, the logic control circuit of this application also realizes the switching between independent charging of the lithium battery device 300, independent operation of the electrolytic hydrogen production device 200, and simultaneous operation of the lithium battery device 300 and the electrolytic hydrogen production device 200 in series and parallel, achieving maximum energy utilization under all weather and operating conditions. In off-grid scenarios, when the grid cannot supply power and continuous power supply to the load is required, the hydrogen produced by the electrolytic hydrogen production device 200 can be directly used for hydrogen power generation. For example, a general hydrogen storage system can be used to extend the hydrogen power generation system to supply power to the load or charge the lithium battery device 300.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen-electric hybrid energy storage system suitable for both off-grid and grid-connected applications, characterized in that, The system includes: a DC-DC power controller (600), an electrolysis hydrogen production device (200), a lithium battery device (300), a logic control circuit, and a renewable energy-based power generation device (100). The DC-DC power controller (600) is electrically connected to the power generation device (100) via a DC bus; the logic control circuit is electrically connected to the DC-DC power controller (600), and the lithium battery device (300) and the electrolytic hydrogen production device (200) are connected to the logic control circuit; The logic control circuit is configured to: based on the output power characteristics of the power generation device (100), control the lithium battery device (300) to be electrically connected to the DC bus via the DC-DC power controller (600) for charging or discharging; or control the electrolytic hydrogen production device (200) to be electrically connected to the DC bus via the DC-DC power controller (600) for electrolytic hydrogen production; or control the lithium battery device (300) and the electrolytic hydrogen production device (200) to be connected in series and then electrically connected to the DC bus via the DC-DC power controller (600).

2. The system according to claim 1, characterized in that, The power generation device (100) is a distributed photovoltaic power generation device, or the power generation device (100) is a wind power generation device.

3. The system according to claim 1, characterized in that, The logic control circuit includes a first switching control mechanism (410) disposed between the lithium battery device (300) and the DC-DC power controller (600), a second switching control mechanism (420) disposed between the electrolytic hydrogen production device (200) and the DC-DC power controller (600), and a third switching control mechanism disposed between the lithium battery device (300) and the electrolytic hydrogen production device (200).

4. The system according to claim 2, characterized in that, The power generation device (100) is a distributed photovoltaic power generation device; The logic control circuit is configured as follows: When the light intensity is at a high or medium level and stable: During the start-up and shutdown phase of the system, the lithium battery device (300) and the electrolytic hydrogen production device (200) are connected in series and electrically connected to the DC bus via the DC-DC power controller (600). After the system starts and stops, the lithium battery device (300) is charged by connecting it to the DC bus via the DC-DC power controller (600), while the lithium battery device (300) is disconnected from the series connection with the electrolytic hydrogen production device (200), and the electrolytic hydrogen production device (200) is disconnected from the DC-DC power controller. After the lithium battery device (300) reaches a first preset power level, the lithium battery device (300) and the electrolytic hydrogen production device (200) are connected in series and electrically connected to the DC bus via the DC-DC power controller (600). When the light intensity is at a high level and fluctuates greatly: The lithium battery device (300) and the electrolytic hydrogen production device (200) are connected in series and are electrically connected to the DC bus via the DC-DC power controller (600); After the lithium battery device (300) reaches the second preset power level, the series connection between the lithium battery device (300) and the electrolytic hydrogen production device (200) is disconnected, and the electrical connection between the lithium battery device (300) and the DC-DC power controller (600) is disconnected. At the same time, the electrolytic hydrogen production device (200) is controlled to be electrically connected to the DC bus via the DC-DC power controller (600) to perform electrolytic hydrogen production. When the light intensity is at a medium level and the light intensity fluctuation is downward, or when the lithium battery device (300) is fully charged: The electrolytic hydrogen production device (200) is controlled to be electrically connected to the DC bus via the DC-DC power controller (600) to perform electrolytic hydrogen production; When the light level is low and the light intensity is stable: The lithium battery device (300) is only controlled to be electrically connected to the DC bus via the DC-DC power controller (600) to charge the lithium battery device (300); Among them: when the real-time light intensity reaches 80% or above of the preset rated light intensity, it is defined as strong light level; when the real-time light intensity reaches 50% to 80% of the preset rated light intensity, it is defined as medium light level; when the real-time light intensity is less than 50% of the preset rated light intensity, it is defined as weak light level; stable light intensity is defined as the change in current per second does not exceed 5% of the current in the previous second. If the change in current per second exceeds 5% of the previous change within any continuous 30 seconds of operation, it is considered light intensity fluctuation; a downward change in current exceeding 1% is considered downward light intensity fluctuation.

5. The system according to claim 4, characterized in that, The logic control circuit also includes a light intensity sensor; the light intensity sensor is used to monitor light intensity.

6. The system according to claim 4, characterized in that, The first preset charge is 90% of the rated capacity of the lithium battery device (300).

7. The system according to claim 4, characterized in that, The second preset power level is 100% of the rated capacity of the lithium battery device (300).

8. The system according to claim 1, characterized in that, It also includes a housing (500); the DC-DC power controller (600), the lithium battery device (300) and the logic control circuit are all located inside the housing (500).

9. The system according to claim 8, characterized in that, The electrolytic hydrogen production device is fixedly installed on the outer wall of the box (500).

10. The system according to claim 8, characterized in that, The front panel of the housing (500) is provided with an openable and closable door.

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