CN114374220A - An electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and control method - Google Patents

Abstract

The invention provides an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and a control method, the application scenarios and efficiency of the system are expanded through technical coupling; the power of fluctuating power is realized through electrochemical cell coupling Smooth and short-term storage; realize active consumption and long-term storage of fluctuating power through the coupling of hydrogen production-hydrogen storage-hydrogen fuel cell through electrolysis of water; improve the power supply and operation stability of hydrogen production system through the combined operation of electrochemical cell-hydrogen production system , prolong the service life; at the same time, the electrochemical cell system can provide starting power for hydrogen production and hydrogen fuel cell devices under off-grid conditions.

Description

An electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and control method

technical field

The invention belongs to the technical field of renewable energy, and in particular relates to an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and a control method.

Background technique

Renewable energy power such as wind power and photovoltaics has become an important development direction of my country's energy transformation due to its advantages of green environmental protection, no depletion crisis, safety and reliability, and short construction period. However, renewable energy power has the characteristics of randomness and intermittentness, which makes it difficult to connect to the grid, adjust, consume and store. At the same time, the distribution of renewable energy resources is uneven, and the construction of power transmission channels is lagging behind. Further development and utilization form obstacles.

Energy storage is an effective way to improve the output characteristics of large-scale renewable energy, improve demand-side response, shave peaks and fill valleys, and consume electricity from renewable energy. The two fastest growing energy storage technologies include electrochemical energy storage and hydrogen energy storage. Among them, electrochemical energy storage has the advantages of flexible configuration, rapid response, and easy integration. However, it can only meet short-term electrical energy storage and cannot actively consume renewable energy power. Hydrogen energy storage is based on the clean mutual conversion between electric energy and hydrogen energy through the electrolysis of water and hydrogen production technology and fuel cell technology. The prepared hydrogen can be stably stored in gas, liquid and solid forms. An efficient way to store at scale.

However, the fluctuation and intermittency of renewable energy power will have an impact on the stable operation of the hydrogen production system. Due to the limitation of the operation mechanism, hydrogen production from alkaline electrolysis water can only operate within the range of 50% to 100% of the rated power. Running at too low power is risky. In the case of power fluctuation, the response time of the alkaline water electrolysis hydrogen production system is more than a minute; for the proton exchange membrane electrolysis water hydrogen production, the input power fluctuation will affect the service life of the catalyst and diaphragm of the hydrogen production system, and damage the stability of the system. sex. On the other hand, compared with electrochemical cells, the start-up time and response time of hydrogen fuel cells are slower, and there are limitations in applications such as system frequency regulation and power quality improvement. Therefore, it is necessary to improve the stability of the coupled renewable energy water electrolysis hydrogen production system, and at the same time expand the application scenarios of the hydrogen energy storage system.

SUMMARY OF THE INVENTION

The first objective of the present invention is to provide an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system in view of the defects existing in the prior art.

For this reason, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

An electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system, comprising an electrochemical cell system, an electrolysis water hydrogen production device, a hydrogen storage device, a hydrogen fuel cell power generation device, an AC/DC device, a DC /DC devices, DC/AC devices, circuit breakers, transformers, energy management systems;

The electrochemical cell system is bidirectionally connected to the AC busbar in the field area through an AC/DC device and a transformer, and the output end is connected to the input end of electrolyzed water for hydrogen production through the DC/DC device;

The input end of the electrolyzed water hydrogen production device is connected to the external input AC bus through the AC/DC device and the transformer at the same time;

The hydrogen storage device is connected with the water electrolysis hydrogen production device and the hydrogen fuel cell power generation device through a pipeline;

The hydrogen fuel cell power generation device can utilize the hydrogen input from the hydrogen storage device and the input air from the environment to generate direct current, and is connected to the AC bus in the field area through a DC/AC device and a transformer.

While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

As a preferred technical solution of the present invention: the electrochemical battery system can be dispatched by an energy management system to selectively output power to the AC busbar in the field area or output power to a water electrolysis hydrogen production device through a DC/DC device.

As a preferred technical solution of the present invention: the electrolyzed water hydrogen production device can independently or simultaneously utilize the electrochemical battery system to convert the input power through the DC/DC device, and the external AC busbar can work after the input power is changed through the transformer and the AC/DC device, and Convert electrical energy to hydrogen.

As a preferred technical solution of the present invention, the energy management system can adjust the operation state of the coupled energy storage system in real time according to the power of the power generation system connected to the grid, the limit power of the grid connection and the operating state of the system under grid-connected conditions:

When the power generated by the connected power generation system is greater than the sum of the grid-connected limit power and the rated power of the electrolyzed water, the energy management system dispatches the electrolyzed water hydrogen production device to convert the excess electrical energy into hydrogen, and the electrochemical battery system is in a charging state;

When the power generated by the connected power generation system is less than or equal to the sum of the grid-connected limit power and the rated power of electrolyzed water, if the electrolyzed water device is already running, the electrochemical cell is dispatched to be in discharge mode to supply power to the hydrogen production system to maintain stable hydrogen production power. , if the water electrolysis device is not started, the electrochemical battery is scheduled to be in a charged state;

When the power generated by the connected power generation system is less than the rated power of the electrolyzed water, the energy management system can dispatch the electrochemical battery system to supply power to the hydrogen production system to maintain the stability of the input power of the electrolytic hydrogen production system.

As a preferred technical solution of the present invention: the energy management system can adjust the operation state of the coupled energy storage system in real time according to the power of the connected power generation system, user requirements and system operation state under off-grid conditions:

When the power generated by the connected power generation system is greater than the rated power of hydrogen production from water electrolysis, the energy management system dispatches the water electrolysis hydrogen production device to convert electrical energy into hydrogen, and the electrochemical battery system is in a charging state; When the rated power of hydrogen production is between the rated power and the operable power, the hydrogen production operation of electrolyzed water is maintained, and the electrochemical cell is in a standby state.

When the power generated by the connected power generation system is less than the operable power of the electrolyzed water, if the electrolyzed water device is already running and the electrochemical cell is in a state of charge, the electrochemical cell is dispatched to be in the discharge mode to supply power to the hydrogen production system to maintain stable hydrogen production power. ; If the electrochemical cell is in a dead state, schedule the electrochemical cell to be in a charged state.

As a preferred technical solution of the present invention: the input end of the hydrogen fuel cell power generation device is connected to the output end of the electrochemical cell system through a DC/DC device. When the hydrogen fuel cell power generation system is started, the auxiliary equipment is powered by the electrochemical cell system. After the start-up is completed, the auxiliary equipment can be self-powered by the hydrogen fuel cell, so that the system can be started under the condition of grid power failure.

The second object of the present invention is to provide a control method of an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under grid-connected conditions in view of the defects in the prior art.

For this reason, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

According to the aforementioned control method of the electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under grid-connected conditions, the following steps are included:

The energy management system in the electrochemical cell-electrolyzed water hydrogen production-hydrogen storage-hydrogen fuel cell coupled energy storage system can monitor the operating status of each subsystem in real time, and according to the power connected to the power generation system, the grid connection limits the power and user needs, and the coupling Adjustment of the operating state of the energy storage system: under grid-connected conditions, when the power generation system is connected to the power generation system, the coupled energy storage system is activated;

1) If the power of the abandoned electricity is greater than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery, the energy management system dispatches the electrolyzed water hydrogen production device to run at the rated power, and the electrochemical battery system is in the maximum power charging state;

2) If the water electrolysis device is in the power-on mode, and the power of the abandoned electricity is greater than or equal to the rated power of hydrogen production, the hydrogen production system is running at the rated power;

3) If the water electrolysis device is in the power-on mode, and the power of discarded electricity is less than the rated power of hydrogen production, and the electrochemical cell is in a state of charge, the electrochemical cell is dispatched to be in discharge mode to supply power to the hydrogen production system to maintain stable hydrogen production power;

4) If the water electrolysis device is in the power-on mode, and the power of discarded electricity is less than the rated power of hydrogen production, and the electrochemical cell is in a dry state, the hydrogen production system is dispatched to stop working, and the electrochemical cell is in the charging mode;

5) If the water electrolysis device is in shutdown mode, and the power of discarded electricity is greater than or equal to the rated power of hydrogen production, the hydrogen production system is dispatched to start, and the electrochemical battery is in a charged state;

6) If the water electrolysis device is in shutdown mode, and the power of discarded electricity is less than the rated power of hydrogen production, the hydrogen production system is kept inactive, and the electrochemical battery is dispatched to be in a charging state.

Another object of the present invention is to provide a control method of an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under off-grid conditions in view of the defects in the prior art.

For this reason, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

According to the aforementioned control method of the electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under off-grid conditions, the following steps are included:

The energy management system in the electrochemical cell-hydrogen production by electrolysis water-hydrogen storage-hydrogen fuel cell coupled energy storage system can monitor the operating status of each subsystem in real time, and operate the coupled energy storage system according to the power of the connected power generation system and the operating status of the system. State to adjust: In off-grid conditions:

1) If the power of the connected power generation system is greater than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery, the energy management system dispatches the water electrolysis hydrogen production device to run at the rated power, and the electrochemical battery system is in the maximum power charging state;

2) If the power of the connected power generation system is greater than the rated power of hydrogen production, but not less than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery, the hydrogen production system is running at the rated power;

3) If the power connected to the power generation system is greater than the operable power of the electrolyzed water hydrogen production system, but less than the rated power of hydrogen production, the hydrogen production system will run;

4) If the power of the connected power generation system is less than the operational power of hydrogen production, and the hydrogen production system is in the power-on mode, if the electrochemical cell is in a state of charge, the electrochemical cell supplies power for the hydrogen production system; If it is in the electric state, the hydrogen production system will be shut down, and the electrochemical cell will be in the charging mode;

5) If the power connected to the power generation system is less than the operational power of hydrogen production, and the hydrogen production system is in shutdown mode, the hydrogen production system will remain inactive and the electrochemical cell will be in a charged state.

The invention provides an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and a control method, and the application scenarios and efficiency of the system are expanded through technical coupling; the power of fluctuating power is realized through electrochemical cell coupling Smooth and short-term storage; active consumption and long-term storage of fluctuating power through the coupling of water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell; through the joint operation of electrochemical cell-hydrogen production system, the power supply and operation stability of the hydrogen production system are improved , prolong the service life; at the same time, the electrochemical cell system can provide starting power for hydrogen production and hydrogen fuel cell devices under off-grid conditions.

The invention can store the fluctuating power such as photovoltaic/wind power generation in the form of electric energy and hydrogen energy for short-term or long-term storage according to user needs; at the same time, when the fluctuation of input electric energy is relatively large, the electrochemical cell system and the electrolysis water hydrogen production device can be operated jointly , improve the stability of the input power of the hydrogen production system; through the coordination and interaction of various systems, improve the development capacity of renewable energy resources.

Compared with the prior art, the electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system and control method provided by the present invention have the following advantages:

(1) Compared with the traditional single water electrolysis hydrogen production system, in the process of “electricity-to-hydrogen” coupled with renewable energy power, due to the fluctuation and intermittency of the input power, the operation safety and stability of the hydrogen production system are greatly affected. , increase the energy consumption of the system; when the input power fluctuates violently, the present invention can use the internal electrochemical battery of the system to suppress the fluctuation of the input power of the hydrogen system, and realize the stable "electricity-to-hydrogen" process coupled with the fluctuating power supply.

(2) Compared with the traditional single electrochemical battery energy storage system, when the grid-connected power is limited or the external load power is insufficient, the energy storage is difficult to improve the consumption of renewable energy. The present invention is based on the electrolysis of water to produce hydrogen with hydrogen storage and fuel. The battery system enables the system to have a certain active power consumption capacity, especially suitable for the northwest region of my country, where renewable energy is abundant but the power sent to the grid is limited, which helps to improve the regional renewable energy development capacity.

(3) Compared with the traditional energy storage products which are single electric energy or hydrogen energy, the present invention can realize that the energy storage products can be proportionally adjustable hydrogen energy and electric energy by adjusting and controlling the configuration and control strategy of hydrogen and electrochemical cells. Application scenarios richer.

(4) In the present invention, the output end of the electrochemical cell system and the input end of the electrolysis water hydrogen production and hydrogen fuel cell power generation device are connected by DC/DC, which simplifies the system components, reduces the energy loss caused by power electronic conversion, and can realize the system in Off-grid start.

Description of drawings

FIG. 1 is a schematic diagram of an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system provided by the present invention.

Fig. 2 is a flow chart of a control method of an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under grid-connected conditions.

Fig. 3 is a flow chart of a control method of an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under off-grid conditions.

FIG. 4 is a power output diagram of the electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system provided by the present invention.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

As shown in Figure 1, an electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system includes an electrochemical cell system, an electrolysis water hydrogen production device, a hydrogen storage device, a hydrogen fuel cell power generation device, AC/DC installations, DC/DC installations, DC/AC installations, circuit breakers, transformers, energy management systems.

The electrochemical battery system is bidirectionally connected to the AC busbar in the field area through the AC/DC device, the circuit breaker K ₁ and the transformer #1; meanwhile, the output end of the electrochemical battery is connected to the input end of the electrolysis water hydrogen production through the circuit breaker K ₂ and the DC/DC device. , and the circuit breaker K ₃ , the DC/DC device is connected to the input end of the hydrogen fuel cell; the input end of the electrolyzed water hydrogen production device is simultaneously connected to the AC bus in the field area through the AC/DC device, the circuit breaker, the AC/DC device and the transformer #2 ; The output end of the hydrogen fuel cell device is connected to the AC bus in the field through the DC/AC device, circuit breaker K ₅ and transformer #3; the external unstable power is input to the coupled energy storage through the AC bus, and the system AC bus passes through the circuit breaker K ₅ Control system grid access or external load access.

The electrochemical cell system can be dispatched by the energy management system to selectively output power to the system AC bus or output power through the DC/DC unit to the water electrolysis hydrogen production unit.

The water electrolysis hydrogen production device can independently or simultaneously use the electrochemical battery system to convert the input power through the DC/DC device and the AC bus in the field area through the transformer and the AC/DC device to change the input power to work, and convert electrical energy into hydrogen.

The hydrogen storage device is connected with the water electrolysis hydrogen production device and the hydrogen fuel cell power generation device through the pipeline; the output end of the hydrogen fuel cell power generation device is connected with the system AC busbar through the DC/AC device and the transformer.

The energy management system can monitor the operating status of each subsystem in real time, and adjust the operating status of the coupled energy storage system according to the power connected to the power generation system, the grid-connected power limit and user needs: as shown in Figure 2, when K6 is closed, that is The coupled energy storage system is in grid-connected state. Under grid-connected conditions, the coupled energy storage system will start when there is power abandonment in the access power generation system;

1) When the power of abandoned electricity is greater than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery (ΔP-Ps> P _{H amount} + P _E ), the energy management system dispatches the water electrolysis hydrogen production device to convert the excess electric energy into hydrogen, At the same time, the electrochemical battery system is in a state of maximum power charging;

2) If the water electrolysis device is in the power-on mode, and the power of abandoned electricity is greater than or equal to the rated power of hydrogen production, the hydrogen production system is running at the rated power, and the charging power of the energy storage system P _E = ΔP-Ps-P _H ;

3) If the water electrolysis device is in the power-on mode, and the power of discarded electricity is less than the rated power of hydrogen production, and the electrochemical cell is in a state of charge, the electrochemical cell is dispatched to be in discharge mode to supply power to the hydrogen production system to maintain the stability of the hydrogen production power; the energy storage system Discharge power P _E = P _{H amount-} (ΔP-Ps);

4) If the water electrolysis device is in the power-on mode, and the power of discarded electricity is less than the rated power of hydrogen production, and the electrochemical cell is in a dry state, the hydrogen production system is dispatched to stop working, and the electrochemical cell is in the charging mode P _E =ΔP-Ps;

5) If the water electrolysis device is in shutdown mode, and the discarded power is greater than or equal to the maximum charging power of the electrochemical battery, the hydrogen production system is scheduled to start, the electrochemical battery is in the charging state, and the charging power P _E = ΔP-Ps-P _H ;

6) If the water electrolysis device is in the shutdown mode and the power discarded is less than the maximum charging power of the electrochemical cell, the electrochemical cell is scheduled to be in the charging mode, and the charging power P _E = ΔP-Ps.

The energy management system can monitor the operating status of each subsystem in real time, and adjust the operating status of the coupled energy storage system according to the power of the connected power generation system and the operating status of the system: as shown in Figure 3, when K6 is disconnected, the coupled storage The energy system is off-grid. In off-grid conditions:

1) If the power connected to the power generation system is greater than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery (ΔP> P _H + P _E ), the energy management system dispatches the electrolysis water hydrogen production device to run at the rated power, while the electricity The chemical battery system is in the maximum power charging state;

2) If the power connected to the power generation system is greater than the rated power of hydrogen production, but not less than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery (P _{H amount} + P _E ≥ ΔP > P _{H amount} ), the hydrogen production system Running at rated power, the electrochemical battery system charging power P _E =ΔP- _PH ;

3) If the power connected to the power generation system is greater than the operable power of the electrolyzed water hydrogen production system, but less than the rated power of hydrogen production, the operating power of the hydrogen production system P _H = ΔP;

4) If the power of the connected power generation system is less than the operational power of hydrogen production, and the hydrogen production system is in the power-on mode, if the electrochemical cell is in a state of charge, the electrochemical cell supplies power for the hydrogen production system, and the discharge power P _E = P _H -ΔP; if the electrochemical cell is in a dry state, the hydrogen production system is shut down, and the electrochemical cell is in the charging mode P _E =ΔP;

5) If the power of the connected power generation system is less than the operable power of hydrogen production, and the hydrogen production system is in shutdown mode, the hydrogen production system is kept inactive, the electrochemical cell is in a charging state, and the charging power P _E = ΔP.

Full text up and down: ΔP is the power connected to the power generation system, Ps is the grid-connected limit power, PE is the charge and discharge power of the electrochemical battery, P _H is the power _{of the hydrogen production system, and P H and} P _{H min} are the rated and Minimum operational power.

More specifically, an electrochemical cell-hydrogen production from water electrolysis-hydrogen storage-hydrogen fuel cell coupled energy storage system, including a 15MW/30MWh electrochemical cell system, a 15MW electrolysis water hydrogen production system, and a 100 m ³ 1.6 MPa cylindrical hydrogen storage system device, 3000 kW hydrogen fuel cell power generation device, and AC/DC device, DC/DC device, DC/AC device, circuit breaker, transformer, energy management system; this coupled energy storage system is used for photovoltaic fields with a rated power of 100 MW District supporting energy storage: On a certain day, the daily output curve of the photovoltaic field is shown in Figure 4. According to the grid dispatching demand, from 10:00 am to 14:00 pm every day, the photovoltaic grid-connected power P _S =60 MW.

From 10:50 to 11:40, the photovoltaic field power generation is 60MW<ΔP≤75 MW. At this time, the energy management system dispatches the electrochemical battery system to be in the charging mode, and the charging power _{P E} =ΔP-PS .

From 11:40 to 12:20, at this time, the power generation of the photovoltaic field is 75MW <ΔP≤90 MW. At this time, the energy management system dispatches the water electrolysis hydrogen production system to operate at the rated power P _H , and the hydrogen storage device operates, and the hydrogen produced Stored in the tank while the electrochemical cell system continues to be in charging mode, charging power P _E = ΔP - P _S - P _H .

From 12:20 to 13:00, at this time, the power generation of the photovoltaic field is 60MW <ΔP≤75 MW. At this time, the energy management system dispatches the electrolysis water hydrogen production system to run at rated power, and dispatches the electrochemical battery system to be in discharge mode, and the discharge power P _E = P _H + P _S -ΔP.

From 13:00 to 13:25, at this time, the power generation of the photovoltaic field is 75MW <ΔP≤90 MW. At this time, the electrolytic water hydrogen production system continues to operate at the rated power P _H , and the energy management system dispatches the electrochemical battery system to continue to be charged. mode, charging power P _E =ΔP-PS-P _{H .}

From 13:25 to 14:00, at this time, the power generation of the photovoltaic field is 60MW <ΔP≤75 MW. At this time, the energy management system dispatches the electrolyzed water hydrogen production system to run at rated power, and dispatches the electrochemical battery system to be in discharge mode, and the discharge power P _E = P _H + P _S -ΔP.

After 14:00, the electrolytic water hydrogen production system stops working, and the electrochemical battery system is dispatched by the grid.

At the same time, in the event of a power failure in the power grid, the energy management system dispatches the hydrogen fuel cell power generation device to use the hydrogen storage device to input hydrogen and ambient input air to generate direct current, and to supply power to the field AC bus through the DC/AC device and transformer; When the system is started, the auxiliary equipment is powered by the electrochemical battery system. When the start-up is completed, the auxiliary equipment can generate self-power through the hydrogen fuel cell, so that the system can be started under the condition of grid power failure.

Through the combined operation of electrochemical cell-hydrogen production-hydrogen storage, the power abandoned in the photovoltaic field can be effectively absorbed and converted into hydrogen products at the same time. Under the condition of fluctuating power input, the hydrogen production system always keeps working near rated power, Helps to improve its operational stability.

The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. It should be pointed out that for those skilled in the art, some improvements can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (9)

1. An electrochemical cell-water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell coupling energy storage system is characterized in that: the electrochemical cell-water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell coupling energy storage system comprises an electrochemical cell system, a water electrolysis hydrogen production device, a hydrogen storage device, a hydrogen fuel cell power generation device, an AC/DC device, a DC/AC device, a circuit breaker, a transformer and an energy management system;

the electrochemical battery system is bidirectionally connected with an AC bus of the field area through an AC/DC device and a transformer, and the output end of the electrochemical battery system is connected with the input end of the electrolytic water hydrogen production through the DC/DC device;

the input end of the water electrolysis hydrogen production device is connected with an external input AC bus through an AC/DC device and a transformer;

the hydrogen storage device is connected with the water electrolysis hydrogen production device and the hydrogen fuel cell power generation device through pipelines;

the hydrogen fuel cell power generation device can utilize hydrogen input by the hydrogen storage device and ambient input air to generate direct current and is connected with the AC bus of the field area through the DC/AC device and the transformer.

2. The electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system of claim 1, wherein: the electrochemical cell system can accept the energy management system to schedule selective output power to the AC bus of the site or to the electrolytic water hydrogen plant via the DC/DC device.

3. The electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system of claim 1, wherein: the water electrolysis hydrogen production device can independently or simultaneously utilize an electrochemical cell system to convert input power through a DC/DC device, an external AC bus works through the input power after the input power is changed by a transformer and the AC/DC device, and electric energy is converted into hydrogen.

4. The electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system of claim 1, wherein: under the condition of grid connection, the energy management system can adjust the running state of the coupled energy storage system in real time according to the power of the power generation system, the grid connection limiting power and the running state of the system:

when the power generation power of the accessed power generation system is larger than the sum of the grid-connected limiting power and the electrolyzed water rated power, the energy management system dispatches the electrolyzed water hydrogen production device to convert redundant electric energy into hydrogen, and meanwhile, the electrochemical battery system is in a charging state;

when the power generation power of the connected power generation system is less than or equal to the sum of the grid-connected limiting power and the electrolyzed water rated power, if the electrolyzed water device is operated, the electrochemical cell is scheduled to be in a discharge mode to supply power for the hydrogen production system, the hydrogen production power is maintained to be stable, and if the electrolyzed water device is not started, the electrochemical cell is scheduled to be in a charging state;

when the power generation power of the power generation system is smaller than the rated power of the electrolyzed water, the energy management system can schedule the electrochemical battery system to supply power for the hydrogen production system, and the stability of the input power of the hydrogen production system is maintained.

5. The electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system of claim 1, wherein: under the off-grid condition, the energy management system can adjust the running state of the coupled energy storage system in real time according to the power of the power generation system, the user demand and the running state of the system:

when the power generation power of the connected power generation system is larger than the rated power of hydrogen production by water electrolysis, the energy management system dispatches the hydrogen production device by water electrolysis to convert electric energy into hydrogen, and the electrochemical battery system is in a charging state; if the power generation power of the power generation system is connected to be between the rated power and the operable power for hydrogen production by water electrolysis, the hydrogen production by water electrolysis is maintained to be operated, and the electrochemical cell is in a standby state.

6. When the power generation power of the connected power generation system is smaller than the operable power of the electrolyzed water, if the water electrolysis device is operated and the electrochemical cell is in a charged state, the electrochemical cell is scheduled to be in a discharge mode to supply power to the hydrogen production system, so that the stability of the hydrogen production power is maintained; and if the electrochemical battery is in a power-off state, the electrochemical battery is scheduled to be in a charging state.

7. The electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system of claim 1, wherein: the input end of the hydrogen fuel cell power generation device is connected with the output end of the electrochemical cell system through the DC/DC device, when the hydrogen fuel cell power generation system is started, the auxiliary equipment supplies power through the electrochemical cell system, and after the hydrogen fuel cell power generation system is started, the auxiliary equipment can generate power through the hydrogen fuel cell and supply power to the hydrogen fuel cell, so that the system is started under an off-grid condition.

8. The control method of the electrochemical cell-water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell coupling energy storage system under the grid-connected condition according to claim 1 is characterized in that: the method comprises the following steps:

the energy management system in the electrochemical cell-water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell coupled energy storage system can monitor the running state of each subsystem in real time, and regulate the running state of the coupled energy storage system according to the power of the power generation system, the grid-connected limited power and the user requirements: under the condition of grid connection, when the power generation system is accessed and power is abandoned, the coupling energy storage system is started;

1) if the abandoned electric power is larger than the sum of the hydrogen production rated power and the maximum charging power of the energy storage battery, the energy management system schedules the water electrolysis hydrogen production device to operate at the rated power, and meanwhile, the electrochemical battery system is in the maximum power charging state;

2) if the water electrolysis device is in a starting mode and the electric power is abandoned to be greater than or equal to the rated power of hydrogen production, the hydrogen production system operates at the rated power;

3) if the water electrolysis device is in a starting mode, the abandoned electric power is smaller than the hydrogen production rated power, and the electrochemical cell is in a charged state, the electrochemical cell is scheduled to be in a discharging mode to supply power for the hydrogen production system, and the hydrogen production power is maintained to be stable; (ii) a

4) If the water electrolysis device is in a starting mode, the abandoned electric power is smaller than the hydrogen production rated power, and the electrochemical battery is in a power-off state, the hydrogen production system is scheduled to stop working, and the electrochemical battery is in a charging mode;

5) if the water electrolysis device is in a shutdown mode and the abandoned electric power is greater than or equal to the rated power of hydrogen production, the hydrogen production system is scheduled to be started, and the electrochemical battery is in a charging state;

6) and if the water electrolysis device is in a shutdown mode and the abandoned electric power is smaller than the rated power of hydrogen production, maintaining the hydrogen production system to be inactive and scheduling the electrochemical battery to be in a charging state.

9. The control method of the electrochemical cell-hydrogen production by electrolysis of water-hydrogen storage-hydrogen fuel cell coupled energy storage system under the off-grid condition according to claim 1 is characterized in that: the method comprises the following steps:

the energy management system in the electrochemical cell-water electrolysis hydrogen production-hydrogen storage-hydrogen fuel cell coupled energy storage system can monitor the running state of each subsystem in real time, and regulate the running state of the coupled energy storage system according to the power accessed into the power generation system and the running state of the system: under off-grid conditions:

1) if the power of the power generation system is larger than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery, the energy management system schedules the hydrogen production device by water electrolysis to operate at the rated power, and meanwhile, the electrochemical battery system is in the maximum power charging state;

2) if the power of the power generation system is higher than the rated power of hydrogen production but not lower than the sum of the rated power of hydrogen production and the maximum charging power of the energy storage battery, the hydrogen production system operates at the rated power;

3) if the power of the power generation system is higher than the operable power of the water electrolysis hydrogen production system but lower than the rated hydrogen production power, the hydrogen production system operates;

4) if the power of the power generation system is less than the hydrogen production running power, the hydrogen production system is in a starting mode, and if the electrochemical cell is in a charge state, the electrochemical cell supplies power to the hydrogen production system; if the electrochemical battery is in a power-off state, the hydrogen production system is shut down, and the electrochemical battery is in a charging mode;

5) and if the power of the accessed power generation system is smaller than the hydrogen production running power, and the hydrogen production system is in a shutdown mode, the hydrogen production system is kept not to act, and the electrochemical battery is in a charging state.

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