A reversible solid oxide battery system

Abstract

The present invention relates to a reversible solid oxide battery system, comprising a battery stack, an external power grid, an air heat exchanger, a hydrogen heat exchanger, and a combustion chamber. The battery stack has an electric heating unit, and is provided with a hydrogen inlet, an air inlet, a hydrogen outlet, and an air outlet. The electric heating unit is connected to the external power grid via a solid-state relay. The hydrogen electrode and oxygen electrode within the battery stack are respectively connected to the external power grid via a bidirectional adjustable inverter. The air outlet is connected to the shell-side inlet of the air heat exchanger, the hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger, the shell-side outlet of the hydrogen heat exchanger is connected to a hydrogen compression processing system, the tube-side outlet of the air heat exchanger is connected to the air inlet, the tube-side outlet of the hydrogen heat exchanger is connected to the hydrogen inlet, the hydrogen outlet and the air outlet are respectively connected to the combustion chamber, and the combustion chamber is respectively connected to the air heat exchanger and the hydrogen heat exchanger. Advantages: The system's operating mode (power generation or hydrogen production) can be adjusted according to the load demand of the external power grid.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a reversible solid oxide battery system. Background Art

[0002] Solid oxide fuel cells (SOFCs) are a new, highly efficient power generation technology that converts chemical energy stored in fuel directly into electrical energy. Due to their all-solid-state nature, high energy conversion efficiency, wide fuel selection, and low catalyst cost, they are considered one of the most promising fuel cell technologies. The solid oxide electrolyzer (SOEC), a reverse SOFC process, uses electricity to efficiently electrolyze water to produce hydrogen. Compared to low-temperature electrolysis technologies, SOECs operate at high temperatures, requiring less electricity and promising large-scale energy conversion and storage. SOEC technology offers a range of advantages, including high efficiency, reliability, and environmental friendliness. However, to achieve flexible grid load adjustment based on these two technologies, SOFC / SOEC systems must be operated in parallel. This involves large equipment investment (two stacks and auxiliary systems), low energy utilization (when either system is operating, the other must remain warm), and high system complexity (necessitating communication and control between the two control systems). Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a reversible solid oxide battery system, which effectively overcomes the defects of the prior art.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] A reversible solid oxide battery system includes a battery stack, an air heat exchanger, a hydrogen heat exchanger and a combustion chamber. The battery stack has an electric heating unit for heating it. The battery stack is provided with a hydrogen inlet, an air inlet, a hydrogen outlet and an air outlet. The electric heating unit is connected to an external power grid via a solid-state relay. The hydrogen electrode and the oxygen electrode inside the battery stack are connected to the external power grid via a bidirectional adjustable inverter. The air outlet is connected to the shell-side inlet of the air heat exchanger via a pipeline. The hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger via a pipeline. The shell-side outlet of the hydrogen heat exchanger is connected to the shell-side outlet of the hydrogen heat exchanger via a pipeline. The hydrogen compression processing system and the tail gas discharge pipeline are respectively connected, the tube-side inlet of the above-mentioned air heat exchanger is connected to the air delivery pipeline, the tube-side outlet of the above-mentioned air heat exchanger is connected to the above-mentioned air inlet through a pipeline, the tube-side inlet of the above-mentioned hydrogen heat exchanger is respectively connected to the hydrogen delivery pipeline and the deionized water delivery pipeline, the tube-side outlet of the above-mentioned hydrogen heat exchanger is connected to the above-mentioned hydrogen inlet through a pipeline, the above-mentioned hydrogen outlet and air outlet are respectively connected to the inlet of the above-mentioned combustion chamber through pipelines, and the outlet of the above-mentioned combustion chamber is respectively connected to the shell-side inlet of the above-mentioned air heat exchanger and the shell-side inlet of the above-mentioned hydrogen heat exchanger through pipelines.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the electric heating unit is an electric heating wire.

[0008] Furthermore, a blower is connected to the port of the air delivery pipeline, and an air flow meter is provided on the air delivery pipeline.

[0009] Furthermore, a water pump is provided on the deionized water delivery pipeline.

[0010] Furthermore, the hydrogen compression processing system includes a hydrogen cooler, a hydrogen dryer and a hydrogen compressor. The shell side outlet of the hydrogen heat exchanger, the inlet and outlet of the hydrogen cooler, the inlet and outlet of the hydrogen dryer and the inlet of the hydrogen compressor are connected in sequence through pipelines.

[0011] Furthermore, a first valve is provided on the pipeline between the air outlet and the shell-side inlet of the air heat exchanger, a second valve is provided on the pipeline between the hydrogen outlet and the shell-side inlet of the hydrogen heat exchanger, a third valve is provided on the pipeline between the hydrogen outlet and the inlet of the combustion chamber, a fourth valve is provided on the pipeline between the air outlet and the inlet of the combustion chamber, a fifth valve is provided on the pipeline between the outlet of the combustion chamber and the shell-side inlet of the air heat exchanger, a sixth valve is provided on the pipeline between the outlet of the combustion chamber and the shell-side inlet of the hydrogen heat exchanger, a seventh valve is provided on the exhaust gas pipeline, and an eighth valve is provided on the pipeline at the inlet of the hydrogen cooler.

[0012] Furthermore, a flow controller is provided on the hydrogen delivery pipeline.

[0013] The beneficial effects of the present invention are: reasonable system design, high flexibility in modular design, integration of the functions of SOFC and SOEC, ability to realize integrated co-power generation and co-electrolysis, and ability to adjust the system's operating mode (power generation or hydrogen production) according to the load demand of the external power grid; after integration, the two operating modes share the fuel supply, air supply, and control system, which reduces equipment investment, energy loss, system complexity, and power grid stability compared to the parallel operation of separate SOFC and SOEC systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the reversible solid oxide battery system of the present invention.

[0015] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0016] 1. Fuel cell stack; 2. External power grid; 3. Air heat exchanger; 4. Hydrogen heat exchanger; 5. Combustion chamber; 6. Solid-state relay; 7. Bidirectional adjustable inverter; 8. Photovoltaic generator set; 9. Wind turbine generator set; 11. Electric heating unit; 12. Hydrogen electrode; 13. Oxygen electrode; 101. Blower; 102. Air flow meter; 103. Water pump; 201. Hydrogen cooler; 202. Hydrogen dryer; 203. Hydrogen compressor; 301. First valve; 302. Second valve; 303. Third valve; 304. Fourth valve; 305. Fifth valve; 306. Sixth valve; 307. Seventh valve; 308. Eighth valve; 401. Flow controller. DETAILED DESCRIPTION

[0017] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0018] Example: Figure 1 As shown, the reversible solid oxide battery system of this embodiment includes a fuel cell stack 1, an air heat exchanger 3, a hydrogen heat exchanger 4 and a combustion chamber 5. The fuel cell stack 1 has an electric heating unit 11 for heating it. The fuel cell stack 1 is provided with a hydrogen inlet, an air inlet, a hydrogen outlet and an air outlet. The electric heating unit 11 is connected to the external power grid 2 through a solid-state relay 6. The hydrogen electrode 12 and the oxygen electrode 13 inside the fuel cell stack 1 are connected to the external power grid 2 through a bidirectional adjustable inverter 7 respectively. The air outlet is connected to the shell-side inlet of the air heat exchanger 3 through a pipeline, and the hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger 4 through a pipeline. The shell-side outlet of the air heat exchanger 4 is respectively connected to the hydrogen compression processing system and the tail gas discharge pipeline, the tube-side inlet of the above-mentioned air heat exchanger 3 is connected to the air delivery pipeline, the tube-side outlet of the above-mentioned air heat exchanger 3 is connected to the above-mentioned air inlet through a pipeline, the tube-side inlet of the above-mentioned hydrogen heat exchanger 4 is respectively connected to the hydrogen delivery pipeline and the deionized water delivery pipeline, the tube-side outlet of the above-mentioned hydrogen heat exchanger 4 is connected to the above-mentioned hydrogen inlet through a pipeline, the above-mentioned hydrogen outlet and air outlet are respectively connected to the inlet of the above-mentioned combustion chamber 5 through pipelines, and the outlet of the above-mentioned combustion chamber 5 is respectively connected to the shell-side inlet of the above-mentioned air heat exchanger 3 and the shell-side inlet of the above-mentioned hydrogen heat exchanger 4 through pipelines.

[0019] In this embodiment, the fuel cell stack 1 is provided with a temperature monitor and is connected to the control system. At the same time, current and voltage monitoring devices such as ammeters can be respectively provided on the circuit connecting the external power grid 2 and the above-mentioned hydrogen electrode 12 and oxygen electrode 13, as well as on the circuit connecting the external power grid 2 and the electric heating unit 11, and are respectively connected to the control system. In the event of abnormal temperature and current, the control system alarms (the control system has its own alarm circuit, which belongs to the existing technology and will not be elaborated here).

[0020] Taking the system as an example, heating from room temperature to SOEC working state and switching to SOFC working state after working for a period of time, the working process is briefly described as follows:

[0021] The system needs to operate at a certain temperature, so the stack unit in the system needs to be heated. The specific operation steps are as follows:

[0022] ① Keep the pipelines between the hydrogen outlet and the air outlet and the air heat exchanger 3 and the hydrogen heat exchanger 4 unobstructed, and close the tail gas emission pipeline. At the same time, open the inlet pipeline and outlet pipeline of the combustion chamber 5.

[0023] ② A small amount of air is delivered to the fuel cell stack 1 through the air delivery pipeline via the air heat exchanger 3. At the same time, a small amount of hydrogen is introduced into the fuel cell stack 1 through the hydrogen delivery pipeline.

[0024] When the temperature of the stack unit reaches 800°C, the operating mode of the system is selected according to the load of the external power grid 2 and the load change trend. The specific instructions are as follows:

[0025] (1) When the load of the external grid 2 is low, the system adopts the SOEC electrolysis mode to electrolyze water to generate hydrogen and collect it, specifically:

[0026] ① Open the pipeline between the hydrogen compression processing system and the hydrogen heat exchanger 4, and close the tail gas emission pipeline;

[0027] ② According to the temperature change of the fuel cell stack 1, adjust the output current of the solid-state relay 6 to ensure that the temperature of the fuel cell stack 1 is stable at 800℃, and adjust the current direction of the bidirectional adjustable inverter 7 to supply power from the external power grid 2 to the fuel cell stack 1.

[0028] ③ A small amount of water is introduced into the fuel cell stack 1 through the deionized water pipeline. Based on the load on the external power grid 2, the hydrogen and deionized water quantities are adjusted first, followed by the input current of the bidirectionally adjustable inverter 7. The operating strategy here is to adjust the current of the bidirectionally adjustable inverter 7 when the load on the external power grid 2 is high, striving to keep the grid load within a certain range. The hydrogen produced by electrolysis is collected at the outlet of the hydrogen compression and processing system.

[0029] (2) When the load of the external grid 2 is high, the system adopts the SOFC power generation mode to consume the hydrogen generated by the previous electrolysis to generate electricity. The specific operation steps are as follows:

[0030] ① Stop the current input of the solid-state relay 6, stop the current input of the bidirectional adjustable inverter 7, and stop the delivery of deionized water to the fuel cell stack 1;

[0031] ② First open the tail gas emission pipeline, close the pipeline between the hydrogen compression processing system and the hydrogen heat exchanger 4, then open the pipeline between the combustion chamber 5 and the hydrogen outlet and the hydrogen heat exchanger 4 (to make the pipeline unobstructed), at the same time, open the pipeline between the combustion chamber 5 and the air outlet and the air heat exchanger 3 (to make the pipeline unobstructed), then close the pipeline between the air outlet and the hydrogen outlet, the air heat exchanger 3 and the hydrogen heat exchanger 4 respectively;

[0032] ③ Adjust the hydrogen inlet flow rate of the hydrogen flow controller to stabilize the fuel cell unit at 750°C. At this time, hydrogen enters the fuel cell after passing through the hydrogen heat exchanger and enters the combustion chamber through the fuel cell gas outlet. The exhaust gas is divided into two parts, one entering the air heat exchanger and the other entering the hydrogen heat exchanger.

[0033] ④ Adjust the current direction of the bidirectional adjustable inverter 7 to output electric energy to the external grid 2,

[0034] ⑤ Increase the hydrogen flow rate into stack 1, increase the air flow rate into stack 1, and increase the output current of bidirectional adjustable inverter 7. Ensure that the temperature of stack 1 remains stable at 750°C. The operating strategy here is to consume the hydrogen generated by electrolysis to generate electricity as the load on external grid 2 continues to decrease, thereby maintaining a stable load on external grid 2.

[0035] More specifically, the basic operating principle of the reversible solid oxide battery system of this embodiment is as follows:

[0036] This system has two working modes: SOEC (water electrolysis) mode, with an operating temperature of 800°C; SOFC (power generation) mode, with an operating temperature of 750°C.

[0037] In SOEC mode, the external grid 2 inputs current to the electric heating unit 11 through the solid-state relay 6 to heat the stack 1. Deionized water from the deionized water pipeline and hydrogen from the hydrogen pipeline enter the hydrogen heat exchanger 4 for preheating. Air from the air pipeline enters the air heat exchanger 3. After the two heat exchanges, the gases enter the stack 1. The water is electrolyzed by the current input from the bidirectional adjustable inverter 7, producing hydrogen at the hydrogen electrode 12 and oxygen at the oxygen electrode 13. The resulting high-temperature gases return to the two heat exchangers (hydrogen heat exchanger 4 and air heat exchanger 3) through the hydrogen and air outlets, respectively, to preheat the gases entering the stack 1. The hydrogen is compressed and collected by the hydrogen compression and processing system. The oxygen-enriched air is directly discharged into the atmosphere.

[0038] SOFC mode: Stop the current input of solid-state relay 6. Hydrogen enters hydrogen heat exchanger 4 and then enters fuel cell stack 1. Air enters air heat exchanger 3 and then enters fuel cell stack 1. Set the current direction of bidirectional adjustable inverter 7 to output (that is, the fuel cell stack 1 outputs to the external power grid 2). Adjusting the output current adjusts the output power of the system. The unused hydrogen and air enter the combustion chamber 5 through the air outlet and hydrogen outlet of the fuel cell stack 1 respectively for mixed combustion. The exhaust gas after combustion enters two heat exchangers (hydrogen heat exchanger 4 and air heat exchanger 3) to preheat the air entering the fuel cell stack 1 to maintain the temperature of the fuel cell stack 1.

[0039] In this embodiment, the electric heating unit 11 may be a conventional electric heating wire.

[0040] In this embodiment, a blower 101 is connected to the port of the above-mentioned air delivery pipeline, and the blower 101 can promote the entry of air into the fuel cell stack 1. The air flow rate sent into the fuel cell stack 1 can be adjusted by adjusting the output power. An air flow meter 102 is provided on the above-mentioned air delivery pipeline, and the air flow rate information entering the fuel cell stack 1 can be monitored in real time by the air flow meter 102, so that the flow rate can be adjusted in time according to the temperature of the fuel cell stack 1 and the monitoring results.

[0041] In this embodiment, a water pump 103 is provided on the deionized water delivery pipeline, and the water pump 103 is used to adjust the flow rate and amount of water input into the fuel cell stack 1 .

[0042] As a preferred embodiment, the above-mentioned hydrogen compression processing system includes a hydrogen cooler 201, a hydrogen dryer 202 and a hydrogen compressor 203, and the shell side outlet of the above-mentioned hydrogen heat exchanger 4, the inlet and outlet of the hydrogen cooler 201, the inlet and outlet of the hydrogen dryer 202 and the inlet of the above-mentioned hydrogen compressor 203 are connected in sequence through pipelines.

[0043] In the above embodiment, when the hydrogen compression processing system is in operation, the collected hydrogen is first cooled, then dried, and finally compressed and collected and stored in a dedicated hydrogen storage bottle.

[0044] As a preferred embodiment, a first valve 301 is provided on the pipeline between the air outlet and the shell-side inlet of the air heat exchanger 3, a second valve 302 is provided on the pipeline between the hydrogen outlet and the shell-side inlet of the hydrogen heat exchanger 4, a third valve 303 is provided on the pipeline between the hydrogen outlet and the inlet of the combustion chamber 5, a fourth valve 304 is provided on the pipeline between the air outlet and the inlet of the combustion chamber 5, a fifth valve 305 is provided on the pipeline between the outlet of the combustion chamber 5 and the shell-side inlet of the air heat exchanger 3, a sixth valve 306 is provided on the pipeline between the outlet of the combustion chamber 5 and the shell-side inlet of the hydrogen heat exchanger 4, a seventh valve 307 is provided on the exhaust gas pipeline, and an eighth valve 308 is provided on the pipeline at the inlet of the hydrogen cooler 201.

[0045] In the above implementation scheme, flexible switching between the SOEC mode and the SOFC mode in the entire system is achieved through the flexible opening and closing of eight valves. Optimally, all eight valves are electrically controlled valves connected to a control system, and the intelligent switching of the eight valves is achieved through the control system. The intelligent switching operation between the SOEC mode and the SOFC mode is achieved in conjunction with the temperature monitoring information of the fuel cell stack 1 and the flow information of hydrogen and air.

[0046] In this embodiment, a flow controller 401 is provided on the hydrogen delivery pipeline, and the flow controller 401 is used to monitor the delivery volume of hydrogen in real time, thereby meeting the gas supply requirements of different modes.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0049] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0050] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0051] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0052] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A reversible solid oxide battery system, characterized in that: The invention comprises a fuel cell stack (1), an air heat exchanger (3), a hydrogen heat exchanger (4) and a combustion chamber (5), wherein the fuel cell stack (1) has an electric heating unit (11) for heating the fuel cell stack, and the fuel cell stack (1) is provided with a hydrogen inlet, an air inlet, a hydrogen outlet and an air outlet, wherein the electric heating unit (11) is connected to an external power grid (2) via a solid-state relay (6), and the hydrogen electrode (12) and the oxygen electrode (13) inside the fuel cell stack (1) are connected to the external power grid (2) via a bidirectional adjustable inverter (7), respectively, and the air outlet is connected to the shell-side inlet of the air heat exchanger (3) via a pipeline, and the hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger (4) via a pipeline, and the hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger (4) via a pipeline, and the hydrogen outlet is connected to the shell-side inlet of the hydrogen heat exchanger (4) via a pipeline. The shell-side outlet of the heat exchanger (4) is respectively connected to the hydrogen compression processing system and the tail gas discharge pipeline, the tube-side inlet of the air heat exchanger (3) is connected to the air delivery pipeline, the tube-side outlet of the air heat exchanger (3) is connected to the air inlet through a pipeline, the tube-side inlet of the hydrogen heat exchanger (4) is respectively connected to the hydrogen delivery pipeline and the deionized water delivery pipeline, the tube-side outlet of the hydrogen heat exchanger (4) is connected to the hydrogen inlet through a pipeline, the hydrogen outlet and the air outlet are respectively connected to the inlet of the combustion chamber (5) through pipelines, and the outlet of the combustion chamber (5) is respectively connected to the shell-side inlet of the air heat exchanger (3) and the shell-side inlet of the hydrogen heat exchanger (4) through pipelines.

2. A reversible solid oxide battery system according to claim 1, characterized in that: The electric heating unit (11) is an electric heating wire.

3. The reversible solid oxide battery system according to claim 1, characterized in that: A blower (101) is connected to the port of the air delivery pipeline, and an air flow meter (102) is provided on the air delivery pipeline.

4. The reversible solid oxide battery system according to claim 1, characterized in that: A water pump (103) is provided on the deionized water delivery pipeline.

5. The reversible solid oxide battery system according to claim 1, characterized in that: The hydrogen compression processing system comprises a hydrogen cooler (201), a hydrogen dryer (202) and a hydrogen compressor (203), and the shell side outlet of the hydrogen heat exchanger (4), the inlet and outlet of the hydrogen cooler (201), the inlet and outlet of the hydrogen dryer (202) and the inlet of the hydrogen compressor (203) are connected in sequence through pipelines.

6. The reversible solid oxide battery system according to claim 5, characterized in that: A first valve (301) is provided on the pipeline between the air outlet and the shell-side inlet of the air heat exchanger (3), a second valve (302) is provided on the pipeline between the hydrogen outlet and the shell-side inlet of the hydrogen heat exchanger (4), a third valve (303) is provided on the pipeline between the hydrogen outlet and the inlet of the combustion chamber (5), a fourth valve (304) is provided on the pipeline between the air outlet and the inlet of the combustion chamber (5), a fifth valve (305) is provided on the pipeline between the outlet of the combustion chamber (5) and the shell-side inlet of the air heat exchanger (3), a sixth valve (306) is provided on the pipeline between the outlet of the combustion chamber (5) and the shell-side inlet of the hydrogen heat exchanger (4), a seventh valve (307) is provided on the exhaust gas pipeline, and an eighth valve (308) is provided on the pipeline at the inlet of the hydrogen cooler (201).

7. A reversible solid oxide battery system according to any one of claims 1 to 6, characterized in that: A flow controller (401) is provided on the hydrogen delivery pipeline.

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