A reversible solid oxide battery system and hydrogen and oxygen preparation method

Abstract

The present invention relates to the field of battery technology, specifically a reversible solid oxide battery system, which optimizes the system's hydrogen production and power generation performance and improves energy conversion efficiency. The system comprises two parts, a SOEC and a SOFC, each of which comprises a battery body, a heating unit, and a material storage and transportation unit. The battery bodies of the SOEC and SOFC both comprise a fuel electrode flow channel, a fuel electrode, an electrolyte, an air electrode, an air electrode flow channel, and a power supply for supplying power to the fuel electrode and the air electrode. The heating units of the SOEC and SOFC both comprise a fuel electrode heater and an air electrode heater. The SOEC and SOFC share a material supply and storage unit, comprising an oxygen storage tank, a water storage tank, and a hydrogen storage tank.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a reversible solid oxide battery system and a method for preparing hydrogen and oxygen based on the system. Background Art

[0002] As the installed capacity of renewable energy sources such as wind power and photovoltaic power generation increases, their volatility poses significant challenges to grid security and balancing energy supply and demand. Hydrogen, as an ideal secondary energy source, can convert instantaneous electrical energy into long-term storable chemical energy on a large scale, breaking down barriers between the power grid and other energy networks and enabling interoperability between different energy sources. Therefore, hydrogen is the energy carrier with the greatest potential to replace traditional fossil fuels in the future.

[0003] Reversible solid oxide cell (RSOC) system can realize the flexible interaction of heterogeneous energy in the electric hydrogen energy system and has broad development space. It consists of two modes: solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC).

[0004] Compared to other methods for hydrogen production by water electrolysis, solid oxide electrolysis cells (SOECs) offer advantages such as all-solid-state, high energy efficiency, fast reaction kinetics, strong flexibility, and great potential. The basic gas distribution method typically involves introducing a mixture of water and hydrogen (typically 90-100% water by mole) into the fuel electrode, and air into the air electrode. SOECs without a regenerative heating system achieve hydrogen production efficiencies ranging from 70-90%, with a voltage of 1.5-3V required for hydrogen production.

[0005] A solid oxide fuel cell (SOFC) is an all-solid-state chemical power generation device that can directly convert the chemical energy stored in fuel and oxidant into electrical energy in an efficient and environmentally friendly manner at medium to high temperatures. Compared to other types of fuel cells, SOFCs have irreplaceable advantages such as an all-solid-state structure, excellent reaction kinetics, no need for precious metal catalysts, and high fuel flexibility. Thanks to their high operating temperature (600-1000°C) and flexible catalyst selection, SOFCs can use not only H2 as a fuel source, but also CO, CH4, NH3, coal, biomass, waste organic matter, and other substances as fuels. The basic gas distribution method for SOFCs using hydrogen as fuel is usually to pass humidified hydrogen (with a water mole fraction of approximately 3%) into the fuel electrode and air into the air electrode. The system's energy conversion efficiency is in the range of 50-70%.

[0006] In order to promote the further development of reversible solid oxide battery systems and provide a large-scale, low-cost hydrogen source for the hydrogen energy industry, improving the energy conversion efficiency of RSOC systems and expanding the scale of hydrogen production have become important goals. However, this is often limited by factors such as reaction kinetics within the battery, gas transport, operational safety, and hydrogen production rate. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology, provide a reversible solid oxide battery system, and a hydrogen and oxygen production method, optimize the system's hydrogen production and power generation performance, and improve energy conversion efficiency.

[0008] The technical solution adopted in the present invention is as follows:

[0009] The reversible solid oxide battery system consists of two parts: SOEC and SOFC. Each part includes a battery body, a heating unit, and a material storage and transportation unit.

[0010] The cell body of SOEC and SOFC both includes a fuel electrode flow channel, a fuel electrode, an electrolyte, an air electrode, an air electrode flow channel, and a power supply for supplying power to the fuel electrode and the air electrode.

[0011] The heating units of SOEC and SOFC both include a fuel electrode heater and an air electrode heater;

[0012] SOEC and SOFC share a material supply and storage unit, including an oxygen storage tank, a water storage tank and a hydrogen storage tank. The oxygen storage tank is connected to the air electrode flow channel inlet of SOFC through the air electrode heater of SOFC to supply oxygen to the air electrode flow channel. The oxygen storage tank is also connected to the air electrode flow channel outlets of SOFC and SOEC; the water storage tank is connected to the fuel electrode heater and air electrode heater of SOEC. The water flowing out of the water storage tank is heated to form water vapor and enters the fuel electrode flow channel and air electrode flow channel of SOEC. The water storage tank is connected to the fuel electrode flow channel and air electrode flow channel outlet of SOEC, as well as the outlet of the fuel electrode flow channel of SOFC; the hydrogen storage tank is connected to the fuel electrode flow channel inlet of SOFC through the fuel electrode heater of SOFC. The hydrogen storage tank is also connected to the fuel electrode flow channel outlets of SOFC and SOEC.

[0013] Preferably, when the SOEC part is working, water vapor is introduced into the fuel electrode flow channel and the air electrode flow channel, and the system is in electrolysis mode.

[0014] Preferably, the flow rate of water vapor introduced into the fuel electrode flow channel and the air electrode flow channel is 50-500 mL / min.

[0015] Preferably, when the SOFC part is working, hydrogen is introduced into the fuel electrode flow channel, oxygen is introduced into the air electrode flow channel, and the system is in fuel cell mode.

[0016] Preferably, the flow rates of hydrogen and oxygen are both 50-500 mL / min.

[0017] Preferably, the fuel electrode heater and the air electrode heater are both provided with an inner tube section and an outer shell flow channel, the inner tube section and the outer shell flow channel are isolated from each other and exchange heat with each other, and the inner tube section is provided with a heating module; the fuel electrode flow channel and the air electrode flow channel inlet of the SOEC and SOFC are both connected to the inner tube section of the corresponding heater, and the fuel electrode flow channel and the air electrode flow channel outlet of the SOEC and SOFC are both connected to the outer shell flow channel of the corresponding heater, and then connected to the corresponding oxygen storage tank, water storage tank or hydrogen storage tank.

[0018] Preferably, the material used for the fuel electrode is Ni-YSZ, the electrolyte is a yttrium-stabilized zirconia / samarium-doped cerium oxide double-layer electrolyte, and the material used for the air electrode is a lanthanum strontium cobalt ferrite material.

[0019] Preferably, the reaction temperature of the battery body is 600-1000°C.

[0020] Preferably, the battery body is a tubular battery.

[0021] The present invention also provides a method for preparing hydrogen and oxygen, which comprises:

[0022] (1) When there is surplus electricity from renewable energy, water vapor is introduced into the fuel and air channels of the SOEC to promote the forward electrolysis reaction and reduce the hydrogen production voltage. The system is in electrolysis mode.

[0023] Fuel electrode (cathode): H2O+2e - →H2+O 2- ;

[0024] Air electrode (anode): O 2- -2e - →0.5O2;

[0025] Water is reduced to hydrogen at the fuel electrode, and O 2- , O 2- It is transported to the air electrode through the electrolyte, where it is oxidized to produce oxygen. The generated oxygen is swept out by the water vapor introduced from the air channel inlet.

[0026] (2) When the power generated by renewable energy is insufficient, pure oxygen is introduced into the air channel of the SOFC to replace air, promoting the forward electrochemical reaction in the fuel cell and putting the system into fuel cell mode;

[0027] Fuel electrode (anode): H2+O 2- →H2O;

[0028] Air electrode (cathode): 0.5O2→O 2- ;

[0029] Oxygen is reduced to O at the air electrode 2- , the generated O 2- It is transported to the fuel electrode through the electrolyte, combines with the fuel electrode hydrogen, and undergoes an oxidation reaction to generate water.

[0030] The present invention has the following beneficial effects:

[0031] (1) Gas distribution method: When in the electrolysis state, water vapor is introduced into the air electrode to replace air; when in the fuel cell state, oxygen is introduced into the air electrode. This gas distribution method promotes the forward movement of the electrochemical reaction, reduces the voltage required for hydrogen production in the electrolytic cell, and increases the power generation capacity of the fuel cell. (2) Heat recovery utilization: The air electrode and oxygen electrode of the system each contain a heat recovery device, which on the one hand reuses the heat energy of the reaction products, and on the other hand saves the heat energy required for preheating the reactants, greatly improving the energy conversion efficiency of the system. (3) Providing pure oxygen for the medical industry: When the system is in the electrolysis mode, the air electrode product is a mixture of oxygen and water. The separation method is simple. In addition to providing reactants for the fuel cell air electrode, the oxygen in the oxygen storage tank can also provide low-cost pure oxygen for the medical industry. The present invention optimizes the system's hydrogen production and power generation performance by designing a reversible solid oxide system, improves the system's energy conversion efficiency, promotes lower-cost and larger-scale utilization of hydrogen energy, and provides a path for the supply of pure oxygen to the medical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is the working principle diagram of the SOEC part when it is in electrolysis mode;

[0034] Figure 2 This is a working principle diagram of the SOFC part when it is in fuel cell mode;

[0035] Figure 3 A schematic diagram of the reversible solid oxide battery system provided by the present invention;

[0036] The picture includes:

[0037] SOEC part:

[0038] first fuel electrode flow channel 1, first fuel electrode inlet 15, first fuel electrode outlet 16, first fuel electrode heater 11, first air electrode heater 12, first air electrode inlet 17, first air electrode outlet 18, first fuel electrode 2, first electrolyte 3, first air electrode 4, first air electrode flow channel 5, oxygen storage tank 23, water storage tank 24, hydrogen storage tank 25, first power supply 26;

[0039] SOFC part:

[0040] Second fuel electrode flow channel 6, second fuel electrode inlet 19, second fuel electrode outlet 20, second fuel electrode 7, second electrolyte 8, second air electrode electrode 9, second air electrode flow channel 10, second air electrode inlet 21, second air electrode outlet 22, second power supply 27; second fuel electrode heater 13, second air electrode heater 14. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0043] The following is further described in conjunction with specific embodiments. Figure 3As shown, the present invention provides a reversible solid oxide cell system (RSOC). The system is divided into two parts: a solid oxide electrolyzer (SOEC) and a solid oxide fuel cell (SOFC). Each part consists of three sections: a cell body, a heating system, and a material storage and transportation system. The SOEC section is equipped with: a first fuel electrode flow channel 1, a first fuel electrode inlet 15, a first fuel electrode outlet 16, a first air electrode inlet 17, a first air electrode outlet 18, a first fuel electrode 2, a first electrolyte 3, a first air electrode 4, a first air electrode flow channel 5, and a first power supply 26. The first fuel electrode 2, the first fuel electrode 2, the first electrolyte 3, the first air electrode 4, and the first air electrode flow channel 5 are arranged in sequence. The first power supply 26 supplies power to the first fuel electrode 2 and the first air electrode 4. The above is the cell body. The first fuel electrode heater 11, the second air electrode heater 12 and its associated pipes, and the heating system above the first fuel electrode flow channel 1. Similar to the SOEC, the SOFC comprises: a second fuel electrode flow channel 6, a second fuel electrode inlet 19, a second fuel electrode outlet 20, a second fuel electrode 7, a second electrolyte 8, a second air electrode 9, a second air electrode flow channel 10, a second air electrode inlet 21, a second air electrode outlet 22, and a second power supply 27. These constitute the cell body. The second fuel electrode heater 13, the second air electrode heater 14, and their associated piping constitute the heating system.

[0044] The oxygen tank 23, water tank 24, hydrogen tank 25, and their associated pipelines constitute the material storage and transportation system, a common component of the SOEC and SOFC. The oxygen tank is connected to the SOFC's air channel inlet via the SOFC's air channel heater, supplying oxygen to the air channel. It is also connected to the air channel outlets of both the SOFC and SOEC. The water tank is connected to the SOEC's fuel channel heater and air channel heater. Water flowing out of the water tank is heated to form water vapor, which then enters the SOEC's fuel channel and air channel. The water tank is connected to the SOEC's fuel channel and air channel outlets, as well as the SOFC's fuel channel outlet. The hydrogen tank is connected to the SOFC's fuel channel inlet via the SOFC's fuel channel heater. It is also connected to the fuel channel outlets of both SOFC and SOEC.

[0045] In order to recover heat, reduce heat loss in the system, and improve the energy conversion efficiency of the RSOC system, the fuel electrode heater and the air electrode heater are both equipped with an inner pipe section and an outer shell flow channel. The inner pipe section and the outer shell flow channel are isolated from each other and exchange heat with each other. The inner pipe section is equipped with a heating module, which is generally arranged at the end of the inner pipe section. The fuel electrode flow channel and the air electrode flow channel inlet of the SOEC and SOFC are both connected to the inner pipe section of the corresponding heater. The fuel electrode flow channel and the air electrode flow channel outlet of the SOEC and SOFC are both connected to the outer shell flow channel of the corresponding heater, and then connected to the corresponding oxygen storage tank, water storage tank, or hydrogen storage tank.

[0046] SOEC and SOFC cells utilize tubular cells, which help ensure the sealing of the electrolytic cell, preventing the escape of gaseous products and the consequent impact on the redox reaction. These tubular cells can be integrated into solid oxide cell stacks via series or parallel connections. Dimensions are as follows: 70 mm in length, 1000 micron fuel electrode flow channel, 760 micron fuel electrode support layer thickness, 10 micron fuel electrode active area, 10 micron electrolyte, 15 micron air electrode, and 1750 micron air electrode flow channel.

[0047] The present invention introduces water into the air electrode of the solid oxide electrolysis cell to play the role of purging and transporting oxygen. Compared with the traditional method of using air as the transport gas for the air electrode of the electrolysis cell, the mole fraction (activity) of oxygen in the air electrode can be reduced, thereby promoting the forward movement of the water electrolysis reaction, reducing the Nernst voltage required for electrolysis, and reducing the electric energy input for hydrogen production, as shown in Formulas 1 and 2.

[0048] E=E 0 -RT / nF*ln(Πa vi products / Πa vi reactants ) Formula 1

[0049] E=E 0 -RT / nF*ln(ΠC H2O / ΠC H2 *C O2 0.5 ) Formula 2

[0050] Formula 1 is the general form of the Nernst equation, and Formula 2 is the Nernst equation for water electrolysis, where C H2O 、C H2 、C O2where represents the molar concentrations of water, hydrogen, and oxygen, respectively. The present invention introduces oxygen generated by electrolysis and stored in an oxygen storage tank into the air electrode of a solid oxide fuel cell. Compared to conventional methods using air as the air electrode reactant in fuel cells, this increases the mole fraction (activity) of oxygen in the reactant, promotes the forward movement of the electrochemical reaction in the fuel cell, increases the Nernst voltage in the fuel cell, and boosts electrical energy output, as shown in Equations 3 and 4.

[0051] E=E 0 +RT / nF*ln(Πa vi reactants / Πa vi productions ) Formula 3

[0052] E=E 0 +RT / nF*ln(ΠC H2 *C O2 0.5 / ΠC H2O ) Formula 4

[0053] Formula 3 is the transformed form of the Nernst equation, and Formula 4 is the Nernst equation for a fuel cell using hydrogen as fuel. H2 、C O2 、C H2O The meaning of is the same as that of Formula 2. In the optional technical solution of the present invention, when the SOEC single cell in the RSOC system is operating, water vapor is introduced into both the fuel electrode and the air electrode at a flow rate of 50-500 mL / min. The water vapor at the air electrode can timely purge and discharge the oxygen generated by the reaction, reducing the cell concentration loss while ensuring the safe operation of the electrolytic cell.

[0054] In an optional technical solution of the present invention, when the SOFC single cell in the RSOC system is working, hydrogen is introduced into the fuel electrode and oxygen is introduced into the air electrode, with a flow rate of 50-500 mL / min.

[0055] According to the above two solutions, the flow rate setting can maintain the temperature within the battery body, stabilize the electrochemical reaction inside the battery body, maintain the electrochemical reaction rate, and ensure battery output performance. At the same time, it ensures that the gas products in the battery body are purged and removed in a timely manner, reducing concentration loss and ensuring safe battery operation.

[0056] In the optional technical solution of the present invention, the material used for the fuel electrode is nickel and yttrium-stabilized zirconia composite metal ceramic material (Ni-YSZ), the electrolyte is a yttrium-stabilized zirconia / samarium-doped cerium oxide double-layer electrolyte, and the material used for the air electrode is lanthanum strontium cobalt ferrite.

[0057] In an optional technical solution of the present invention, the reaction temperature of the reversible solid oxide battery is 600°C-1000°C.

[0058] The chemical reaction in the present invention is shown in Formula 5-8 below:

[0059] (1) Electrolysis mode, please refer to Figure 1 ,

[0060] Fuel electrode (cathode): H2O+2e - →H2+O 2- Formula 5

[0061] Air electrode (anode): O 2- -2e - →0.5O2 Formula 6

[0062] (2) Fuel cell mode, please refer to Figure 2 ,

[0063] Fuel electrode (anode): H2+O 2- →H2O Formula 7

[0064] Air electrode (cathode): 0.5O2→O 2- Formula 8

[0065] The reaction process of the solid oxide electrolytic cell of the present invention is as follows: water vapor is introduced into the inlet of the first fuel electrode flow channel, water is reduced to hydrogen at the first fuel electrode, and O is generated. 2- As shown in Reaction Formula 5, the hydrogen generated by the first fuel electrode and the unreacted water vapor are discharged from the outlet of the first fuel electrode flow channel. 2- It is transported to the first air electrode through the first electrolyte, where it is oxidized to produce oxygen, as shown in Reaction Formula 6. The generated oxygen is swept and carried by the water vapor introduced from the inlet of the first air channel and flows out from the outlet of the first air channel.

[0066] The reaction process of the solid oxide fuel cell of the present invention is as follows: oxygen is introduced into the inlet of the second air electrode flow channel, and oxygen is reduced to O at the second air electrode. 2- As shown in reaction formula 8, the generated O 2- It is transported to the second fuel electrode through the second electrolyte, combines with the fuel electrode hydrogen, and undergoes an oxidation reaction to generate water, as shown in Reaction Equation 7.

[0067] SOEC mode:

[0068] See also Figure 1 、 Figure 3As shown, when renewable energy generation is in surplus, the battery body of the SOEC in the system works, and the fuel electrode process is as follows: the water storage tank 24 supplies water to the fuel electrode, and the water flows through the inner pipe section of the first fuel electrode heater 11, is heated to 600-1000°C to form water vapor, and enters the first fuel electrode flow channel 1 through the fuel electrode inlet 15. The water vapor undergoes a reduction reaction at the second fuel electrode 2 to generate hydrogen and O 2- The unreacted water vapor and the hydrogen generated by the reaction are output from the first fuel electrode outlet 16 and transported to the outer shell flow channel of the first fuel electrode heater 11. After being cooled by the low-temperature reactants flowing through the inner pipe section, the water vapor condenses into water and flows into the water storage tank 24, and the remaining hydrogen flows into the hydrogen storage tank 25. The air electrode process is as follows: O generated by the fuel electrode reaction 2- It is transferred to the air electrode through the electrolyte, where an oxidation reaction occurs to produce oxygen. The water supplied by the water storage tank 24 flows through the inner pipe section of the first air electrode heater 12, is heated to 600-1000°C, and forms water vapor. It flows into the 5 air electrode flow channel through the first air electrode inlet 17, and the oxygen generated by the air electrode is purged. The mixture of oxygen and water vapor is output from the first air electrode outlet 18 and transported back to the outer shell flow channel of the first air electrode heater 12. After being cooled by the water supplied by the water storage tank 24, the water vapor condenses into water and flows into the water storage tank 24, and the remaining oxygen flows into the oxygen storage tank 23.

[0069] When the water level in water tank 24 is too low, it can be used to supply water for electrolysis. The hydrogen and oxygen in oxygen tanks 23 and 25, in addition to being used to power the fuel cell, can also be transported externally, contributing to the hydrogen and pure oxygen supply chain. If the reactants delivered to the cell inlet are not sufficiently hot, a heater can be activated to heat the reactants.

[0070] SOFC mode:

[0071] See also Figure 2 、 Figure 3 As shown, when renewable energy generation is insufficient, the system is in fuel cell mode. The fuel electrode process is as follows: hydrogen is supplied by the hydrogen storage tank 25, and the hydrogen flows through the inner pipe section of the second fuel electrode 13 heater and is heated to 600-1000°C to form water vapor. The water vapor flows into the second fuel electrode flow channel 6 from the second fuel electrode inlet 19. The hydrogen is transferred from the air electrode to the fuel electrode 7. 2-Combined, an oxidation reaction occurs to produce water. The unreacted hydrogen and the water generated by the reaction flow out from the second fuel electrode outlet 20 and are transported to the second fuel electrode 13 heater shell flow channel. They are cooled by the low-temperature reactant H2 flowing through the inner pipe section of the heater. The water vapor condenses into water and flows into the water storage tank 24. The remaining hydrogen flows into the hydrogen storage tank 25. The air electrode process is as follows: oxygen is supplied by the oxygen storage tank, passes through the inner pipe section of the second air electrode heater 14, is heated to 600-1000℃, forms water vapor, flows to the air electrode inlet 21 and flows into the second air electrode flow channel 10. The oxygen undergoes a reduction reaction at the second air electrode 9 to produce O 2- , O 2- It flows through the electrolyte and is transferred to the fuel electrode. The remaining oxygen flows out from the second air electrode outlet 22 and is transported back to the outer shell flow channel of the second air electrode heater 14. After being cooled by the low-temperature reactants flowing through the inner pipe section of the heater, it flows back to the oxygen storage tank 23.

[0072] When the oxygen storage tank 23 and the hydrogen storage tank 25 are insufficiently supplied, the reactants required by the fuel cell need to be supplied thereto. When the temperature of the reactants at the inlet of the SOEC or SOFC cell body is not high enough, the heater can be started to heat the reactants.

[0073] The present invention also provides a method for producing hydrogen and oxygen based on the above-mentioned reversible solid oxide battery system, which is used to produce hydrogen and oxygen. The method comprises:

[0074] (1) When there is surplus electricity from renewable energy, water vapor is introduced into the fuel and air channels of the SOEC to promote the forward electrolysis reaction and reduce the hydrogen production voltage. The system is in electrolysis mode.

[0075] Fuel electrode (cathode): H2O+2e - →H2+O 2- ;

[0076] Air electrode (anode): O 2- -2e - →0.5O2;

[0077] Water is reduced to hydrogen at the fuel electrode, and O 2- , O 2- It is transported to the air electrode through the electrolyte, where it is oxidized to produce oxygen. The generated oxygen is swept out by the water vapor introduced from the air channel inlet.

[0078] (2) When the power generated by renewable energy is insufficient, pure oxygen is introduced into the air channel of the SOFC to replace air, promoting the forward electrochemical reaction in the fuel cell and putting the system into fuel cell mode;

[0079] Fuel electrode (anode): H2+O2- →H2O;

[0080] Air electrode (cathode): 0.5O2→O 2- ;

[0081] Oxygen is reduced to O at the air electrode 2- , the generated O 2- It is transported to the fuel electrode through the electrolyte, combines with the fuel electrode hydrogen, and undergoes an oxidation reaction to generate water.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A reversible solid oxide battery system, characterized in that: It consists of two parts: SOEC and SOFC, each of which includes a battery body, a heating unit, and a material storage and transportation unit; The cell body of SOEC and SOFC both includes a fuel electrode flow channel, a fuel electrode, an electrolyte, an air electrode, an air electrode flow channel, and a power supply for supplying power to the fuel electrode and the air electrode. The heating units of SOEC and SOFC both include a fuel electrode heater and an air electrode heater; SOEC and SOFC share a material storage and transportation unit, including an oxygen storage tank, a water storage tank and a hydrogen storage tank. The oxygen storage tank is connected to the air electrode flow channel inlet of SOFC through the air electrode heater of SOFC to supply oxygen to the air electrode flow channel. The oxygen storage tank is also connected to the air electrode flow channel outlets of SOFC and SOEC; the water storage tank is connected to the fuel electrode heater and air electrode heater of SOEC. The water flowing out of the water storage tank is heated to form water vapor and enters the fuel electrode flow channel and air electrode flow channel of SOEC. The water storage tank is connected to the fuel electrode flow channel and air electrode flow channel outlet of SOEC, as well as the outlet of SOFC fuel electrode flow channel; the hydrogen storage tank is connected to the fuel electrode flow channel inlet of SOFC through the fuel electrode heater of SOFC. The hydrogen storage tank is also connected to the fuel electrode flow channel outlets of SOFC and SOEC; When the SOEC part is working, water vapor is introduced into both the fuel electrode flow channel and the air electrode flow channel, and the system is in electrolysis mode; When the SOFC part is working, hydrogen is introduced into the fuel electrode flow channel and oxygen is introduced into the air electrode flow channel, and the system is in fuel cell mode; The fuel electrode heater and the air electrode heater are both provided with an inner tube section and an outer shell flow channel. The inner tube section and the outer shell flow channel are isolated from each other and exchange heat with each other. The inner tube section is provided with a heating module. The fuel electrode flow channel and the air electrode flow channel inlet of the SOEC and SOFC are both connected to the inner tube section of the corresponding heater. The fuel electrode flow channel and the air electrode flow channel outlet of the SOEC and SOFC are both connected to the outer shell flow channel of the corresponding heater, and then connected to the corresponding oxygen storage tank, water storage tank or hydrogen storage tank.

2. The reversible solid oxide battery system according to claim 1, characterized in that: The flow rate of water vapor introduced into the fuel electrode flow channel and the air electrode flow channel is 50-500 mL / min.

3. The reversible solid oxide battery system according to claim 1, wherein: The flow rates of hydrogen and oxygen were both 50-500 mL / min.

4. The reversible solid oxide battery according to claim 1, wherein: The material used for the fuel electrode is Ni-YSZ, the electrolyte is a yttrium-stabilized zirconia / samarium-doped cerium oxide double-layer electrolyte, and the material used for the air electrode is a lanthanum strontium cobalt ferrite material.

5. The reversible solid oxide battery according to claim 1, wherein: The reaction temperature of the battery body is 600-1000°C.

6. The reversible solid oxide battery according to claim 1, wherein: The battery body is a tubular battery.

7. A method for producing hydrogen and oxygen based on a reversible solid oxide battery according to any one of claims 1 to 6, characterized in that: The method includes: (1) When there is surplus electricity from renewable energy, water vapor is introduced into the fuel and air channels of the SOEC to promote the forward electrolysis reaction and reduce the hydrogen production voltage. The system is in electrolysis mode. Fuel electrode: H2O+2e - →H2+O 2- ; Air electrode: O 2— -2e - →0.5O2; Water is reduced to hydrogen at the fuel electrode, and O 2- , O 2- It is transported to the air electrode through the electrolyte, where it is oxidized to produce oxygen. The generated oxygen is swept out by the water vapor introduced from the air channel inlet. (2) When the power generated by renewable energy is insufficient, pure oxygen is introduced into the air channel of the SOFC to replace the air, promoting the forward electrochemical reaction in the fuel cell and putting the system into fuel cell mode; Fuel electrode: H2+O 2- →H2O; Air electrode: 0.5O2→O 2- ; Oxygen is reduced to O at the air electrode 2- , the generated O 2- It is transported to the fuel electrode through the electrolyte, combines with the fuel electrode hydrogen, and undergoes an oxidation reaction to generate water.

Images