Flow cell and fuel cell system with double-loop combined operation and operation method of flow cell and fuel cell system

Abstract

The invention belongs to the technical field of electrochemical energy storage, and discloses a double-loop combined operation flow cell and fuel cell system and an operation method thereof. The system comprises a first positive electrode electrolyte storage tank, a first main electric pile, a first negative electrode electrolyte storage tank, a hydrogen generator, an oxygen generator, a fuel cell, a second negative electrode electrolyte storage tank, a second main electric pile and a second positive electrode electrolyte storage tank. In the charging / discharging process of the first main electric pile and the charging / discharging process of the second main electric pile, a secondary loop system formed by hydrogen production of the oxygen generator, oxygen production of the hydrogen generator and the fuel cell can be started at the same time, so that double-loop combined operation is realized, and the electricity storage capacity of the flow battery is improved; the discharge power and the discharge capacity of the flow battery are improved through the fuel battery of the secondary loop, and the pollution-free and low-cost operation of the battery system is ensured only by externally adding water consumed by oxygen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and in particular relates to a dual-circuit jointly operated liquid flow battery and fuel cell system and an operating method thereof. Background Art

[0002] Liquid flow battery is an electrochemical energy storage technology. Liquid flow battery usually uses aqueous electrolyte. As an aqueous electrochemical energy storage system, liquid flow battery has a significant disadvantage compared with non-aqueous electrochemical energy storage systems (for example, compared with lithium batteries). The thermodynamic stability voltage window of aqueous liquid flow battery is narrow (oxygen evolution at the positive electrode needs to be limited to ≤1.23V, and the negative electrode is charged to a negative potential to cause hydrogen evolution). Due to the limitation of water electrolysis, water electrolysis will lead to side reactions, namely oxygen evolution at the positive electrode and hydrogen evolution at the negative electrode.

[0003] In a flow battery stack, electrons flow between the positive and negative electrodes in an external circuit, positive and negative ions flow inside the stack, and electrochemical redox reactions occur. The electrochemical reactions and energy storage of active materials in the positive half-cell or negative half-cell of any battery unit can only occur simultaneously. However, electrochemical side reactions will inevitably occur under normal operating conditions of flow batteries. Side reactions will irreversibly consume electrons, resulting in an imbalance in the charge state of the positive and negative electrolytes (charge imbalance for short), and ultimately leading to an imbalance in the capacity of the positive and negative electrodes and a reduction in capacity. Since flow batteries usually control the charging potential not to exceed the limit, and due to the extremely slow electrochemical kinetics of the oxygen evolution reaction and the extremely small oxygen evolution side reaction, the main side reaction of aqueous flow batteries is hydrogen evolution, which is also the main cause of charge imbalance and capacity imbalance in flow batteries.

[0004] In summary, the side reactions produced by aqueous flow batteries will lead to charge imbalance and capacity imbalance in the flow batteries, and the capacity loss will accumulate over multiple cycles (cumulative capacity decay), thereby irreversibly reducing the storage capacity of the flow battery system. Summary of the invention

[0005] In view of the above problems, the present invention provides a dual-circuit combined operation flow battery and fuel cell system and an operation method thereof, which adopts the following technical solutions:

[0006] A dual-circuit jointly operated flow battery and fuel cell system, comprising a first positive electrode electrolyte storage tank, a first main battery stack, a first negative electrode electrolyte storage tank, a hydrogen generator, an oxygen generator, a fuel cell, a second negative electrode electrolyte storage tank, a second main battery stack and a second positive electrode electrolyte storage tank;

[0007] The first positive electrode electrolyte storage tank is connected to the positive electrode of the first main battery stack and the liquid path of the oxygen generator; the first negative electrode electrolyte storage tank is connected to the negative electrode of the first main battery stack and the liquid path of the hydrogen generator;

[0008] The gas outlet of the oxygen generator is connected to the positive electrode inlet of the fuel cell, and the gas outlet of the hydrogen generator is connected to the negative electrode inlet of the fuel cell;

[0009] The second positive electrode electrolyte storage tank is connected to the positive electrode of the second main stack, the second negative electrode electrolyte storage tank is connected to the negative electrode of the second main stack, and the outlet of the second negative electrode electrolyte storage tank is also connected to the negative electrode inlet of the fuel cell.

[0010] Furthermore, the outlet of the first positive electrolyte storage tank is connected to the positive electrolyte inlet of the first main battery stack and the liquid inlet of the oxygen generator through the positive liquid inlet pipe, and the inlet of the first positive electrolyte storage tank is connected to the positive electrolyte outlet of the first main battery stack and the liquid outlet of the oxygen generator through the positive liquid outlet pipe.

[0011] Furthermore, the outlet of the first negative electrolyte storage tank is connected to the negative electrolyte inlet of the first main battery stack and the liquid inlet of the hydrogen generator through the negative electrode liquid inlet pipe, and the inlet of the first negative electrolyte storage tank is connected to the negative electrolyte outlet of the first main battery stack and the liquid outlet of the hydrogen generator through the negative electrode liquid outlet pipe.

[0012] Furthermore, the outlet of the second negative electrolyte storage tank is connected to the negative electrolyte inlet of the second main fuel cell stack through a negative liquid inlet branch, and the inlet of the second negative electrolyte storage tank is connected to the negative electrolyte outlet of the second main fuel cell stack through a negative liquid outlet branch; the gas outlet of the second negative electrolyte storage tank is also connected to the negative inlet of the fuel cell.

[0013] Furthermore, the outlet of the second positive electrolyte storage tank is connected to the positive electrolyte inlet of the second main stack through the positive liquid inlet branch, and the inlet of the second positive electrolyte storage tank is connected to the positive electrolyte outlet of the second main stack through the positive liquid outlet branch.

[0014] Further, the oxygen generator includes a first reaction kettle and a first circulation pump;

[0015] Wherein, the first reactor is provided with a third catalytic layer, a first agitator and a first heater, the first agitator is arranged at the bottom of the first reactor, the first heater is arranged at one side of the first agitator, and the third catalytic layer is arranged above the first agitator and the first heater; the first reactor is provided with a feed inlet at the position of the third catalytic layer; the circulation outlet at the top of the first reactor is connected to the inlet of the first circulation pump, and the outlet of the first circulation pump is connected to the circulation inlet at the bottom of the first reactor.

[0016] Further, the hydrogen generator includes a second reaction kettle and a second circulation pump;

[0017] Wherein, the second reactor is provided with a fourth catalytic layer, a second agitator and a second heater, the second agitator is arranged at the bottom of the second reactor, the second heater is arranged at one side of the second agitator, and the fourth catalytic layer is arranged above the second agitator and the second heater; the second reactor is provided with a feeding port at the position of the fourth catalytic layer; the circulation outlet at the top of the second reactor is connected to the inlet of the second circulation pump, and the outlet of the second circulation pump is connected to the circulation inlet at the bottom of the second reactor.

[0018] Furthermore, an oxygen storage tank is arranged between the gas outlet of the oxygen generator and the positive electrode inlet of the fuel cell, wherein a first air pump is arranged between the gas outlet of the oxygen generator and the inlet of the oxygen storage tank, and a first humidifier, an external oxygen source interface and an external air source interface are arranged between the outlet of the oxygen storage tank and the positive electrode inlet of the fuel cell.

[0019] Furthermore, a hydrogen storage tank is arranged between the gas outlet of the hydrogen generator and the negative electrode inlet of the fuel cell, wherein a sixth valve and a second air pump are arranged between the gas outlet of the hydrogen generator and the inlet of the hydrogen storage tank, the gas outlet of the second negative electrode electrolyte storage tank is connected to one end of the gas pipeline, and the other end of the gas pipeline is connected between the inlet of the hydrogen storage tank and the sixth valve; a second humidifier and an external hydrogen source interface are arranged between the outlet of the hydrogen storage tank and the negative electrode inlet of the fuel cell.

[0020] Furthermore, it also includes an electrolyte tank, and a fifth three-way valve is arranged between the second humidifier and the external hydrogen source interface, the a end of the fifth three-way valve is connected to the second humidifier, the b end of the fifth three-way valve is connected to the external hydrogen source interface and the negative electrode inlet of the fuel cell, and the c end of the fifth three-way valve is connected to the electrolyte tank.

[0021] The present invention also provides a method for operating the dual-circuit combined flow battery and fuel cell system, comprising the following steps:

[0022] During the charging or discharging process of the first main battery stack, Ce in the first cathode electrolyte storage tank 4+ The electrolyte flows into the oxygen generator for discharge and oxygen production. The newly generated Ce 3+ The electrolyte is returned to the first positive electrode electrolyte storage tank;

[0023] During the charging or discharging process of the first main battery stack, the Cr in the first negative electrode electrolyte storage tank 2+ The electrolyte flows into the hydrogen generator to discharge and produce hydrogen;

[0024] The oxygen produced by the oxygen generator is transported to the positive electrode of the fuel cell for reaction, and the hydrogen produced by the hydrogen generator and the hydrogen from the second negative electrode electrolyte storage tank are transported to the negative electrode of the fuel cell for reaction.

[0025] Beneficial effects of the present invention:

[0026] 1. During the charging / discharging process of the first main stack and the second main stack of the present invention, the secondary circuit system consisting of the oxygen generator to produce hydrogen, the hydrogen generator to produce oxygen and the fuel cell can be started simultaneously to realize the dual-circuit joint operation, thereby improving the storage capacity of the liquid flow battery and improving the discharge power and discharge capacity of the liquid flow battery through the secondary circuit fuel cell.

[0027] 2. The reactive substances Ce ions, Cr ions and H + Conservation of energy requires that only the feed port of the oxygen generator in the oxygen production loop needs to be supplemented with the corresponding stoichiometric volume / mass of water consumed in oxygen production. This is suitable for large-scale liquid flow battery energy storage systems and ensures that the liquid flow battery has high storage capacity, high discharge power and discharge capacity, high battery performance, no pollution and low cost (closed loop, only the water consumed in oxygen production needs to be added externally).

[0028] 3. In the battery system of the present invention, the first main battery stack of one circuit, the second main battery stack, and the hydrogen and oxygen production of the second circuit can be operated jointly (due to the storage of Ce ions, Fe and Cr ions in the electrolyte storage tank, the above three can be operated jointly at the same time or at different times, realizing the combination and decoupled independence).

[0029] 4. In the battery system of the present invention, the first main battery stack and the second main battery stack of one circuit and the fuel cell of the second circuit can discharge simultaneously, thereby increasing the discharge power and discharge capacity of the dual-circuit jointly operated liquid flow battery and fuel cell system.

[0030] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic structural diagram of a dual-circuit combined operation liquid flow battery and fuel cell system according to the prior art is shown;

[0033] Figure 2 A schematic flow chart of an operating method of a dual-circuit jointly operated liquid flow battery and fuel cell system according to an embodiment of the present invention is shown.

[0034] In the figure: 1, first positive electrolyte storage tank; 101, first three-way valve; 102, second three-way valve; 2, first electrolyte pump; 3, first heat exchanger; 4, positive electrode inlet pipe; 5, first main battery stack; 6, first positive electrode; 7, first ion exchange membrane; 8, first negative electrode; 9, first positive electrode collector plate; 10, first negative electrode collector plate; 11, positive electrode outlet pipe; 12, first power load; 13, second power load; 131, first charging power supply; 132, second charging power supply; 133, third power load; 14, battery control system; 15, first negative electrolyte storage tank; 16, first positive electrode; 17, first positive electrode; 18, first negative electrode; 19, first positive electrode; 20, first negative electrode; 21, first positive electrode; 22, first negative electrode; 23, first positive electrode; 24, first negative electrode; 25, first negative electrode; 26, first positive electrode; 27, first negative electrode; 28, first positive electrode; 29, first positive electrode; 30, first negative electrode; 31, first negative electrode; 32, second negative electrode; 33, third negative electrode; 34, battery control system; 35, first negative electrode; 36, first negative electrode; 37, first negative electrode; 38, first negative electrode; 39, first negative electrode; 40, first negative electrode; 41, first negative electrode; 42, first negative electrode; 43, first negative electrode; 44, first negative electrode; 45, first negative electrode; 46, first negative electrode; 47, first negative electrode; 48, first negative electrode; 49, first negative electrode; 50, first negative electrode; 51, first negative electrode; tank; 16, second electrolyte pump; 17, second heat exchanger; 18, negative electrode liquid inlet pipe; 19, negative electrode liquid outlet pipe; 20, fourth three-way valve; 21, third three-way valve; 22, hydrogen generator; 221, fourth catalyst layer; 23, feeding port; 24, second agitator; 25, second heater; 26, fourth valve; 27, second circulation pump; 28, second pressure gauge; 29, second safety valve; 30, sixth valve; 31, second air pump; 32, hydrogen storage tank; 321, fourth pressure gauge; 33, second humidifier; 34, oxygen generator; 341, third catalyst layer; 35 , feed port; 36, first agitator; 37, first heater; 38, second valve; 39, first circulation pump; 40, first pressure gauge; 41, first safety valve; 42, fifth valve; 43, first air pump; 44, oxygen storage tank; 441, third pressure gauge; 45, first humidifier; 46, external hydrogen source interface; 47, external oxygen source interface; 48, external air source interface; 49, fuel cell; 50, second negative electrode; 51, first catalyst layer; 52, second ion exchange membrane; 53, second catalyst layer; 54, second positive electrode; 55, second negative current collector Plate; 56, second positive electrode current collecting plate; 57, negative electrode outlet pipe; 58, positive electrode outlet pipe; 59, second negative electrode electrolyte storage tank; 591, nitrogen source; 60, fifth pressure gauge; 61, third electrolyte pump; 62, third heat exchanger; 63, second main fuel cell; 64, third negative electrode; 65, third ion exchange membrane; 66, third positive electrode; 67, third negative electrode current collecting plate; 68, third positive electrode current collecting plate; 69, second positive electrode electrolyte storage tank; 70, fourth electrolyte pump; 71, fourth heat exchanger; 72, electrolyte tank; 73, third circulation pump; 74, fifth three-way valve. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so as to describe the embodiments of the present application described here.

[0037] The embodiment of the present invention provides a dual-circuit jointly operated liquid flow battery and fuel cell system and an operation method thereof, which is generally applicable to aqueous liquid flow batteries and fuel cells, and is combined with hydrogen and oxygen production and fuel cell operation, and is suitable for large-scale liquid flow battery energy storage systems, and ensures high storage capacity, high discharge power and discharge capacity, and high battery performance of the liquid flow battery.

[0038] like Figure 1 As shown, a dual-circuit jointly operated liquid flow battery and fuel cell system includes a first positive electrode electrolyte storage tank 1, a first main battery stack 5, a first negative electrode electrolyte storage tank 15, a hydrogen generator 22, an oxygen generator 34, a fuel cell 49, a second negative electrode electrolyte storage tank 59, a second main battery stack 63 and a second positive electrode electrolyte storage tank 69.

[0039] Among them, the first positive electrode electrolyte storage tank 1 is connected with the positive electrode of the first main battery stack 5 and the liquid path of the oxygen generator 34, including: the outlet of the first positive electrode electrolyte storage tank 1 is connected with the positive electrolyte inlet of the first main battery stack 5 and the liquid inlet of the oxygen generator 34 through the positive electrode liquid inlet pipe 4, and the inlet of the first positive electrode electrolyte storage tank 1 is connected with the positive electrolyte outlet of the first main battery stack 5 and the liquid outlet of the oxygen generator 34 through the positive electrode liquid outlet pipe 11.

[0040] The first negative electrode electrolyte storage tank 15 is connected to the negative electrode of the first main battery stack 5 and the liquid path of the hydrogen generator 22, including: the outlet of the first negative electrode electrolyte storage tank 15 is connected to the negative electrolyte inlet of the first main battery stack 5 and the liquid inlet of the hydrogen generator 22 through the negative electrode liquid inlet pipe 18, and the inlet of the first negative electrode electrolyte storage tank 15 is connected to the negative electrolyte outlet of the first main battery stack 5 and the liquid outlet of the hydrogen generator 22 through the negative electrode liquid outlet pipe 19.

[0041] For example, the first main battery stack 5 includes at least one first battery cell, wherein the first battery cell includes a first negative electrode 8, a first ion exchange membrane 7, a first positive electrode 6, a first negative current collecting plate 10 and a first positive current collecting plate 9, the first ion exchange membrane 7 is arranged between the first negative current collecting plate 10 and the first positive current collecting plate 9, the first positive electrode 6 is arranged in a cavity formed by the first positive current collecting plate 9 and the first ion exchange membrane 7, and the first negative electrode 8 is arranged in a cavity formed by the first negative current collecting plate 10 and the first ion exchange membrane 7.

[0042] When the number of first battery cells is ≥1, a plurality of identical first battery cells are connected in series through a first negative current collecting plate 10 and a first positive current collecting plate 9 to form a first main battery stack 5. At this time, the first negative current collecting plate 10 and the first positive current collecting plate 9 are respectively a negative bipolar plate and a positive bipolar plate.

[0043] The positive and negative electrolytes of the first main stack 5 are both composed of the electrolyte active material Ce 3+ ,Cr 3+ , and supporting electrolyte, the supporting electrolyte is an acidic medium, composed of HCl, H2SO4, perchloric acid, nitric acid, methanesulfonic acid or mixed acid, etc. Methanesulfonic acid can increase the active substance Ce 3+ and Cr 3+ Solubility, the embodiment of the present invention preferably uses a mixed acid of hydrochloric acid / sulfuric acid / nitric acid+methanesulfonic acid. The positive and negative electrolytes in the initial state have the same composition (i.e., the new electrolytes without charge and discharge have the same composition). The positive electrode of the first main stack 5 is Ce. 3+ / Ce 4+ Reaction, the positive electrode can be a carbon-based electrode (carbon felt or graphite felt) with a TiC / TiO2 coating or a carbon-based electrode (carbon felt or graphite felt) with a boron-doped titanium dioxide coating by chemical vapor deposition (CVD). TiC / TiO2 coating and boron-doped titanium dioxide coating effectively reduce the direct contact reaction of the carbon-based electrode in the highly oxidizing Ce-based electrolyte and improve the corrosion resistance of the electrode.

[0044] The gas outlet of the oxygen generator 34 is communicated with the positive electrode inlet of the fuel cell 49 , and the gas outlet of the hydrogen generator 22 is communicated with the negative electrode inlet of the fuel cell 49 .

[0045] The second positive electrode electrolyte storage tank 69 is connected to the positive electrode of the second main battery stack 63, including: the outlet of the second positive electrode electrolyte storage tank 69 is connected to the positive electrolyte inlet of the second main battery stack 63 through the positive electrode liquid inlet branch, and the inlet of the second positive electrode electrolyte storage tank 69 is connected to the positive electrolyte outlet of the second main battery stack 63 through the positive electrode liquid outlet branch.

[0046] The second negative electrode electrolyte storage tank 59 is connected to the negative electrode of the second main battery stack 63, including: the outlet of the second negative electrode electrolyte storage tank 59 is connected to the negative electrolyte inlet of the second main battery stack 63 through the negative electrode liquid inlet branch, and the inlet of the second negative electrode electrolyte storage tank 59 is connected to the negative electrolyte outlet of the second main battery stack 63 through the negative electrode liquid outlet branch; the air outlet of the second negative electrode electrolyte storage tank 59 is also connected to the negative electrode inlet of the fuel cell 49.

[0047] For example, the fuel cell 49 includes at least one second battery unit, which includes a second negative electrode 50, a first catalyst layer 51, a second ion exchange membrane 52, a second catalyst layer 53, a second positive electrode 54, a second negative current collecting plate 55 and a second positive current collecting plate 56.

[0048] Among them, the second ion exchange membrane 52 is arranged between the second negative current collecting plate 55 and the second positive current collecting plate 56, the second positive electrode 54 and the first catalyst layer 51 are arranged in the cavity formed by the second positive current collecting plate 56 and the second ion exchange membrane 52, and the second negative electrode 50 and the second catalyst layer 53 are arranged in the cavity formed by the second negative current collecting plate 55 and the second ion exchange membrane 52.

[0049] When the number of second battery cells is ≥1, a plurality of groups of identical second battery cells are connected in series through a second negative current collecting plate 55 and a second positive current collecting plate 56 to form a fuel cell 49. At this time, the second negative current collecting plate 55 and the second positive current collecting plate 56 are respectively a negative bipolar plate and a positive bipolar plate, and the negative outlet pipe 57 and the positive outlet pipe 58 at the bottom of the fuel cell 49 are externally connected to an exhaust pipe.

[0050] For example, the second main battery stack 63 includes at least one third battery cell, wherein the third battery cell includes a third negative electrode 64, a third ion exchange membrane 65, a third positive electrode 66, a third negative current collecting plate 67 and a third positive current collecting plate 68, the third ion exchange membrane 65 is arranged between the third negative current collecting plate 67 and the third positive current collecting plate 68, the third positive electrode 66 is arranged in a cavity formed by the third positive current collecting plate 68 and the third ion exchange membrane 65, and the third negative electrode 64 is arranged in a cavity formed by the third negative current collecting plate 67 and the third ion exchange membrane 65.

[0051] When the number of third battery cells is ≥1, a plurality of identical third battery cells are connected in series through a third negative electrode current collecting plate 67 and a third positive electrode current collecting plate 68 to form a second main battery stack 63. At this time, the third negative electrode current collecting plate 67 and the third positive electrode current collecting plate 68 are respectively a negative bipolar plate and a positive bipolar plate.

[0052] The positive and negative electrolytes of the second main battery stack 63 are both composed of the electrolyte active material Fe 2+ ,Cr 3+ , and a supporting electrolyte, the supporting electrolyte is acidic HCl or H2SO4 or a mixed acid, and the positive and negative electrode electrolyte compositions in the initial state are the same (that is, the new electrolyte compositions that have not been charged or discharged are the same).

[0053] For example, the oxygen generator 34 includes a first reactor, in which a third catalytic layer 341, a first agitator 36 and a first heater 37 are arranged, wherein the first agitator 36 is arranged at the bottom of the first reactor, the first heater 37 is arranged on one side of the first agitator 36, and the third catalytic layer 341 is arranged above the first agitator 36 and the first heater 37.

[0054] For example, the third catalytic layer 341 includes IrO2, RuO2 nanoparticles, and the base layer is carbon felt or graphite felt or titanium mesh or a fixed bed of SiO2 particles.

[0055] The first reactor is provided with a feed inlet 35 at the position of the third catalytic layer 341 , and the feed inlet 35 is also provided with a first valve. A first pressure gauge 40 and a first safety valve 41 are also provided on the top of the first reactor.

[0056] For example, the oxygen generator 34 also includes a second valve 38 and a first circulation pump 39, the circulation outlet at the top of the first reactor is connected to the inlet of the first circulation pump 39, the outlet of the first circulation pump 39 is connected to the circulation inlet at the bottom of the first reactor, and the second valve 38 is arranged between the circulation outlet at the top of the first reactor and the inlet of the first circulation pump 39.

[0057] For example, the hydrogen generator 22 includes a second reactor, in which a fourth catalytic layer 221, a second agitator 24 and a second heater 25 are arranged, wherein the second agitator 24 is arranged at the bottom of the second reactor, the second heater 25 is arranged on one side of the second agitator 24, and the fourth catalytic layer 221 is arranged above the second agitator 24 and the second heater 25.

[0058] For example, the fourth catalytic layer 221 includes MoS2, Mo2C particles, and the base layer is carbon felt or graphite felt or titanium mesh or SiO2 particle lining.

[0059] The second reactor is provided with a feeding port 23 at the position of the fourth catalytic layer 221 , and the feeding port 23 is also provided with a third valve. A second pressure gauge 28 and a second safety valve 29 are also provided on the top of the second reactor.

[0060] For example, the hydrogen generator 22 also includes a fourth valve 26 and a second circulation pump 27, the circulation outlet at the top of the second reactor is connected to the inlet of the second circulation pump 27, the outlet of the second circulation pump 27 is connected to the circulation inlet at the bottom of the second reactor, and the fourth valve 26 is arranged between the circulation outlet at the top of the second reactor and the inlet of the second circulation pump 27.

[0061] For example, the positive electrode liquid inlet pipe 4 is provided with a first electrolyte pump 2, a first three-way valve 101 and a first heat exchanger 3, wherein the inlet of the first electrolyte pump 2 is connected to the outlet of the first positive electrode electrolyte storage tank 1, the outlet of the first electrolyte pump 2 is connected to the a end of the first three-way valve 101, the b end of the first three-way valve 101 is connected to the first heat exchanger 3 and the positive electrolyte inlet of the first main battery stack 5 in sequence, and the c end of the first three-way valve 101 is connected to the liquid inlet of the oxygen generator 34.

[0062] For example, a second three-way valve 102 is provided on the positive electrode liquid outlet pipe 11, the inlet of the first positive electrode electrolyte storage tank 1 is connected to the a end of the second three-way valve 102, the b end of the second three-way valve 102 is connected to the positive electrolyte outlet of the first main battery stack 5, and the c end of the second three-way valve 102 is connected to the liquid outlet of the oxygen generator 34.

[0063] For example, the negative electrode liquid inlet pipe 18 is provided with a second electrolyte pump 16, a third three-way valve 21 and a second heat exchanger 17, wherein the inlet of the second electrolyte pump 16 is connected to the outlet of the first negative electrode electrolyte storage tank 15, the outlet of the second electrolyte pump 16 is connected to the a end of the third three-way valve 21, the b end of the third three-way valve 21 is connected to the second heat exchanger 17 and the negative electrolyte inlet of the first main battery stack 5 in sequence, and the c end of the third three-way valve 21 is connected to the liquid inlet of the hydrogen generator 22.

[0064] For example, a fourth three-way valve 20 is provided on the negative electrode liquid outlet pipe 19, the inlet of the first negative electrode electrolyte storage tank 15 is connected to the a end of the fourth three-way valve 20, the b end of the fourth three-way valve 20 is connected to the negative electrolyte outlet of the first main fuel cell stack 5, and the c end of the fourth three-way valve 20 is connected to the liquid outlet of the hydrogen generator 22.

[0065] For example, a third electrolyte pump 61 and a third heat exchanger 62 are provided on the negative electrode liquid inlet branch, the inlet of the third electrolyte pump 61 is connected to the outlet of the second negative electrode electrolyte storage tank 59, and the outlet of the second electrolyte pump 16 is connected to the third heat exchanger 62 and the negative electrolyte inlet of the first main battery stack 5 in sequence.

[0066] For example, a fourth electrolyte pump 70 and a fourth heat exchanger 71 are provided on the positive electrode liquid inlet branch, the inlet of the fourth electrolyte pump 70 is connected to the outlet of the second positive electrode electrolyte storage tank 69, and the outlet of the fourth electrolyte pump 70 is connected to the fourth heat exchanger 71 and the positive electrolyte inlet of the first main battery stack 5 in sequence.

[0067] For example, an oxygen storage tank 44 is arranged between the gas outlet of the oxygen generator 34 and the positive electrode inlet of the fuel cell 49, wherein a third pressure gauge 441 is arranged on the oxygen storage tank 44, a fifth valve 42 and a first air pump 43 are arranged between the gas outlet of the oxygen generator 34 and the inlet of the oxygen storage tank 44, a first humidifier 45, an external oxygen source interface 47 and an external air source interface 48 are arranged between the outlet of the oxygen storage tank 44 and the positive electrode inlet of the fuel cell 49, and the external oxygen source interface 47 and the external air source interface 48 can be independently operated by setting the external oxygen source interface 47 and the external air source interface 48.

[0068] For example, a hydrogen storage tank 32 is arranged between the gas outlet of the hydrogen generator 22 and the negative electrode inlet of the fuel cell 49, wherein a fourth pressure gauge 321 is arranged on the hydrogen storage tank 32, a sixth valve 30 and a second air pump 31 are arranged between the gas outlet of the hydrogen generator 22 and the inlet of the hydrogen storage tank 32, the gas outlet of the second negative electrode electrolyte storage tank 59 is connected to one end of the gas pipeline, and the other end of the gas pipeline is connected between the inlet of the hydrogen storage tank 32 and the sixth valve 30; a second humidifier 33 and an external hydrogen source interface 46 are arranged between the outlet of the hydrogen storage tank 32 and the negative electrode inlet of the fuel cell 49.

[0069] For example, a dual-circuit jointly operated liquid flow battery and fuel cell system also includes an electrolyte tank 72, and a fifth three-way valve 74 is arranged between the second humidifier 33 and the external hydrogen source interface 46, the a end of the fifth three-way valve 74 is connected to the second humidifier 33, the b end of the fifth three-way valve 74 is connected to the external hydrogen source interface 46 and the negative electrode inlet of the fuel cell 49, and the c end of the fifth three-way valve 74 is connected to the electrolyte tank 72; a third circulation pump 73 is also arranged on the electrolyte tank 72, and the inlet of the third circulation pump 73 is connected to the outlet at the top of the electrolyte tank 72, and the outlet of the third circulation pump 73 is connected to the inlet at the bottom of the electrolyte tank 72.

[0070] For example, a fifth pressure gauge 60 is disposed on the top of the second negative electrode electrolyte storage tank 59 , and the second negative electrode electrolyte storage tank 59 is connected to a nitrogen source 591 , which may be a nitrogen generator or a nitrogen cylinder.

[0071] For example, a dual-circuit jointly operated liquid flow battery and fuel cell system further includes a first power load 12 , a second power load 13 , a third power load 133 and a battery control system 14 .

[0072] Among them, the positive electrode of the first power load 12 is connected to the positive electrode of the first main power stack 5, and the negative electrode of the first power load 12 is connected to the negative electrode of the first main power stack 5; the positive electrode of the second power load 13 is connected to the positive electrode of the fuel cell 49, and the negative electrode of the first power load 12 is connected to the negative electrode of the fuel cell 49; the positive electrode of the third power load 133 is connected to the positive electrode of the second main power stack 63, and the negative electrode of the third power load 133 is connected to the negative electrode of the second main power stack 63.

[0073] For example, a dual-circuit jointly operated liquid flow battery and fuel cell system also includes a first charging power supply 131 and a second charging power supply 132, wherein the positive electrode of the first charging power supply 131 is connected to the positive electrode of the first main battery stack 5, and the negative electrode of the first charging power supply 131 is connected to the negative electrode of the first main battery stack 5; the positive electrode of the second charging power supply 132 is connected to the positive electrode of the second main battery stack 63, and the negative electrode of the second charging power supply 132 is connected to the negative electrode of the second main battery stack 63.

[0074] The battery control system 14 is in communication connection with the first power load 12, the second power load 13, the third power load 133, the first charging power source 131, and the second charging power source 132. The battery control system 14 is configured with operation control strategies and codes for controlling the charging and discharging of the first charging power source 131 and the second charging power source 132, and the operation of the first power load 12, the second power load 13, and the third power load 133.

[0075] like Figure 2 As shown, an embodiment of the present invention also provides an operation method of a dual-circuit combined operation flow battery and fuel cell system, comprising the following steps:

[0076] S1. During the charging process, the negative electrode electrolyte in the first negative electrode electrolyte storage tank 15 and the positive electrode electrolyte in the first positive electrode electrolyte storage tank 1 are transported to the first main stack 5 for electrochemical redox reaction. The electrons flow between the positive and negative electrodes in the first main stack 5 in the external circuit. During the charging process, the first charging power supply 131 charges the first main stack 5, and the electrons flow from the positive electrode to the negative electrode in the external circuit. After the electrochemical reaction, the negative electrode electrolyte flows out of the first main stack 5 and flows into the first negative electrode electrolyte storage tank 15 for storage. After the electrochemical reaction, the positive electrode electrolyte flows out of the first main stack 5 and flows into the first positive electrode electrolyte storage tank 1 for storage.

[0077] S11. The negative electrode electrolyte in the first negative electrode electrolyte storage tank 15 is driven by the second electrolyte pump 16 and forms the temperature required by the liquid flow battery (for example, the operating temperature is 50-65°C) through the second heat exchanger 17. When the ambient temperature is low, the second heat exchanger 17 heats the electrolyte. When the battery temperature rises (such as high current density circulation causes the battery to heat up), the second heat exchanger 17 cools the electrolyte. The negative electrode electrolyte flows into the first main battery stack 5 to react.

[0078] S12. The positive electrode electrolyte in the first positive electrode electrolyte storage tank 1 is driven by the first electrolyte pump 2 and forms the temperature required by the liquid flow battery (for example, the operating temperature is 50-65°C) through the first heat exchanger 3. When the ambient temperature is low, the first heat exchanger 3 heats the electrolyte; when the battery temperature rises (such as high current density circulation causes the battery to heat up), the first heat exchanger 3 cools the electrolyte. The positive electrode electrolyte flows into the first main battery stack 5 through the first heat exchanger 3.

[0079] S13, the first main battery stack 5 is normally charged, using constant current or constant power to charge from 0V to U1 (1.7-1.9V), constant current density = j normal (Can be set to 10~300mAcm -2). The reactant ions of the positive and negative electrolytes flow inside the first main battery stack 5 and undergo electrochemical oxidation-reduction reactions on the positive and negative electrodes. The electrochemical reactions of the active materials of the positive and negative half-cells of the first battery unit and their energy storage occur simultaneously. During the charging process of the first main battery stack 5, the positive electrode Ce 3+ Oxidized to Ce 4+ ,Cr 3+ Reduction to Cr 2+ , and flow into the first positive electrode electrolyte storage tank 1 and the first negative electrode electrolyte storage tank 15 for storage respectively.

[0080] S2, the discharge process is the same as the charging process, except that the first main stack 5 discharges to the first power load 12. During the discharge process, the positive electrode Ce of the first main stack 5 4+ Reduction to Ce 3+ ,Cr 2+ Oxidized to Cr 3+ , and flow back to the first positive electrode electrolyte storage tank 1 and the first negative electrode electrolyte storage tank 15 respectively.

[0081] The first main battery stack 5 undergoes electrochemical reactions of charging and discharging. At the same time, electrochemical side reactions will inevitably occur under normal operating conditions of the liquid flow battery. The side reactions will irreversibly consume electrons, resulting in an imbalance in the charge state of the positive and negative electrolytes (referred to as charge imbalance), and ultimately leading to an imbalance in the capacity of the positive and negative electrodes and a reduction in capacity.

[0082] During the charging process of the first main stack 5, the electrochemical reactions of the positive and negative electrodes and the side reactions are as follows:

[0083] Positive electrode: Ce 3+ -e - =Ce 4+ , 1.65V vs SHE

[0084] Negative electrode: Cr 3+ +e - =Cr 2+ , -0.41V vs SHE

[0085] Hydrogen evolution side reaction: 2H + +2e - =H2, 0V vs SHE

[0086] During the charging and discharging process of the first main stack 5, the electrochemical reactions of the positive and negative electrodes are as follows:

[0087] Positive electrode: Ce 4+ +e - =Ce 3+ , 1.65V vs SHE

[0088] Negative electrode: Cr 2+-e - =Cr 3+ , -0.41V vs SHE

[0089] S3. During the charging process, the negative electrode electrolyte in the second negative electrode electrolyte storage tank 59 and the positive electrode electrolyte in the second positive electrode electrolyte storage tank 69 are transported to the second main stack 63 for electrochemical redox reaction. The electrons flow between the positive and negative electrodes in the second main stack 63 in the external circuit. During the charging process, the second charging power supply 132 charges the second main stack 63, and the electrons flow from the positive electrode to the negative electrode in the external circuit. The negative electrode electrolyte after the electrochemical reaction flows out of the second main stack 63 and flows into the second negative electrode electrolyte storage tank 59 for storage. The positive electrode electrolyte after the electrochemical reaction flows out of the second main stack 63 and flows into the second positive electrode electrolyte storage tank 69 for storage.

[0090] S31, the negative electrode electrolyte in the second negative electrode electrolyte storage tank 59 is driven by the third electrolyte pump 61, and forms the temperature required by the liquid flow battery (for example, the operating temperature is 50-65°C) through the third heat exchanger 62. When the ambient temperature is low, the third heat exchanger 62 heats the electrolyte; when the battery temperature rises (such as high current density circulation causes the battery to heat up), the third heat exchanger 62 cools the electrolyte, and the negative electrode electrolyte flows into the second main battery stack 63 to react.

[0091] S32. The positive electrode electrolyte in the second positive electrode electrolyte storage tank 69 is driven by the fourth electrolyte pump 70 and forms the required temperature of the liquid flow battery (for example, the operating temperature of the iron-chromium liquid flow battery is 50-65°C) through the fourth heat exchanger 71. When the ambient temperature is low, the fourth heat exchanger 71 heats the electrolyte; when the battery temperature rises (such as high current density circulation causes the battery to heat up), the fourth heat exchanger 71 cools the electrolyte. The positive electrode electrolyte flows into the second main battery stack 63 through the fourth heat exchanger 71.

[0092] S33, the second main battery stack 63 is in normal charging process, using constant current or constant power to charge from 0V to U1, constant current density = j normal The reactant ions of the positive and negative electrolytes flow inside the second main battery stack 63 and undergo electrochemical redox reactions on the positive and negative electrodes. The electrochemical reactions of the active materials of the positive and negative half-cells of the third battery unit and their energy storage occur simultaneously. During the charging process of the second main battery stack 63, the positive Fe 2+ Oxidized to Fe 3+ ,Cr 3+ Reduction to Cr 2+ , flowing into the second positive electrode electrolyte storage tank 69 and the second negative electrode electrolyte storage tank 59 respectively.

[0093] S4, the discharge process is similar to the charging process, except that the second main stack 63 discharges to the third power load 133. During the discharge process, the positive electrode Fe of the second main stack 63 3+ Reduction to Fe 2+ ,Cr 2+ Oxidized to Cr 3+ , and flow back to the second positive electrode electrolyte storage tank 69 and the second negative electrode electrolyte storage tank 59 respectively.

[0094] The second main battery stack 63 undergoes electrochemical reactions of charging and discharging. At the same time, electrochemical side reactions will inevitably occur under normal operating conditions of the liquid flow battery. The side reactions will irreversibly consume electrons, resulting in an imbalance in the charge state of the positive and negative electrolytes (referred to as charge imbalance), and ultimately leading to an imbalance in the capacity of the positive and negative electrodes and a reduction in capacity.

[0095] The electrochemical reactions of the positive and negative electrodes and the side reactions during the charging process of the second main stack 63 are as follows:

[0096] Positive electrode: Fe 2+ -e - =Fe 3+ , 0.77V vs SHE

[0097] Negative electrode: Cr 3+ +e - =Cr 2+ , -0.41V vs SHE

[0098] Hydrogen evolution side reaction: 2H + +2e - =H2, 0V vs SHE

[0099] The electrochemical reactions of the positive and negative electrodes during the discharge process of the second main stack 63 are:

[0100] Positive electrode: Fe 3+ +e - =Fe 2+ , 0.77V vs SHE

[0101] Negative electrode: Cr 2+ -e - =Cr 3+ , -0.41V vs SHE

[0102] S5: During the charging or discharging process of the first main battery stack 5, Ce in the first positive electrode electrolyte storage tank 1 4+ The electrolyte flows into the oxygen generator 34 to discharge and produce oxygen, and the newly generated Ce 3+ The electrolyte is returned to the first positive electrode electrolyte storage tank 1, as follows:

[0103] Ce 4+The electrolyte is catalyzed by the third catalytic layer 341, stirred by the first stirrer 36, heated by the first heater 37, and self-circulated by the first circulation pump 39, thereby increasing the oxygen production reaction rate. The first pressure gauge 40 monitors the pressure, and the first safety valve 41 discharges the overpressure in an accident. The positive electrode electrolyte Ce 4+ The oxygen generator 34 discharges oxygen and the oxygen production equation is as follows: 4+ +2H2O=O2+4H + +4Ce 3+ , the newly generated Ce 3+ The electrolyte returns to the first positive electrode electrolyte storage tank 1 for continued charging of the first main battery stack 5 , thereby increasing the storage capacity of the first main battery stack 5 .

[0104] S6: During the charging or discharging process of the first main battery stack 5, the Cr in the first negative electrode electrolyte storage tank 15 2+ The electrolyte flows into the hydrogen generator 22 to discharge and produce hydrogen, as follows:

[0105] Cr 2+ The electrolyte is catalyzed by the fourth catalytic layer 221, stirred by the second agitator 24, heated by the second heater 25, and self-circulated by the second circulation pump 27, which increases the hydrogen production reaction rate. The second pressure gauge 28 monitors the pressure, and the second safety valve 29 discharges the accidental overpressure. The negative electrode electrolyte Cr2+ flows into the hydrogen generator 22 for discharge. The hydrogen production equation is as follows: 4Cr 2+ +4H + =2H2+4Cr 3+ , hydrogen production reactant H + H obtained from the above oxygen production circuit + , diffuses across the membrane to the negative electrode of the first main stack 5 during the charging process, H + The Cr2+ flows into the hydrogen generator 22 and is reduced to H2. 3+ The electrolyte returns to the first negative electrode electrolyte for continued charging of the first main battery stack 5 , thereby increasing the power storage capacity of the first main battery stack 5 .

[0106] The first main stack 5 and the second main stack 63 of the first circuit, and the fuel cell 49 of the second circuit can discharge simultaneously, thereby increasing the discharge power and discharge capacity of the dual-circuit joint operation liquid flow battery and fuel cell 49 system.

[0107] Due to the above joint operation, the reactive species Ce ions, Cr ions and H + Conservation of energy requires that the feed port 35 of the oxygen generator 34 of the oxygen production loop only needs to be supplemented with water of the corresponding stoichiometric volume / mass consumed in oxygen production.

[0108] S7, the oxygen prepared by the oxygen generator 34 is transported to the positive electrode of the fuel cell 49 for reaction, including: the oxygen prepared by the oxygen generator 34 is driven by the first air pump 43 and then enters the oxygen storage tank 44 for storage, and then flows into the positive electrode of the fuel cell 49 for reaction after being humidified by the first humidifier 45.

[0109] S8, the hydrogen prepared by the hydrogen generator 22 and the hydrogen from the second negative electrode electrolyte storage tank 59 (hydrogen produced by the hydrogen evolution side reaction of the second main stack 63) are transported to the negative electrode reaction of the fuel cell 49, including: the hydrogen prepared by the hydrogen generator 22 and the hydrogen from the second negative electrode electrolyte storage tank 59 are driven by the second air pump 31 and enter the hydrogen storage tank 32 for storage, and are humidified by the second humidifier 33 and then flow into the negative electrode reaction of the fuel cell 49. The fuel cell 49 also supports a high-power reaction mode that is resistant to flooding, and the acidic electrolyte from the electrolyte tank 72 flows into the negative electrode for a high-power reaction.

[0110] The dual-circuit combined operation liquid flow battery and fuel cell system and its operation method of the embodiment of the present invention are generally applicable to aqueous liquid flow batteries and fuel cells 49 (supporting electrolytes are neutral or acidic, such as sulfuric acid, hydrochloric acid, perchloric acid, nitric acid, methanesulfonic acid or mixed acid systems), and are combined with hydrogen and oxygen production and fuel cell 49 operation (due to the setting of electrolyte storage tanks and gas storage tanks, the reactants and electrochemical stoichiometric conservation between electrolyte charging and discharging and hydrogen and oxygen production, the dual circuits can be simultaneous or decoupled), suitable for large-scale liquid flow battery energy storage systems, and ensure that the liquid flow battery has high storage capacity, high discharge power and discharge capacity, high battery performance, pollution-free and low cost (closed circuit, only water consumed by oxygen production needs to be added externally). The first main stack 5 and the second main stack 63 of the first circuit, the hydrogen and oxygen production of the second circuit, and the fuel cell 49 of the second circuit can be combined or decoupled to operate independently, which increases the flexibility of the energy storage system and expands the storage capacity and use (for example, hydrogen filling and hydrogen use after hydrogen production is sent out).

[0111] The two-circuit system consisting of hydrogen production, oxygen production and fuel cell 49 in the embodiment of the present invention and its operation method. During the charging / discharging process of the first main stack 5 and the charging / discharging process of the second main stack 63, the two-circuit system consisting of the oxygen generator 34 for hydrogen production, the hydrogen generator 22 for oxygen production and the fuel cell 49 can be started at the same time to realize the joint operation of the two circuits, thereby improving the storage capacity of the liquid flow battery, and improving the discharge power and discharge capacity of the liquid flow battery through the fuel cell 49 of the two circuits.

[0112] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-circuit combined operation flow battery and fuel cell system, characterized in that: It comprises a first positive electrode electrolyte storage tank (1), a first main battery stack (5), a first negative electrode electrolyte storage tank (15), a hydrogen generator (22), an oxygen generator (34), a fuel cell (49), a second negative electrode electrolyte storage tank (59), a second main battery stack (63) and a second positive electrode electrolyte storage tank (69); The first positive electrode electrolyte storage tank (1) is in communication with the positive electrode of the first main battery stack (5) and the liquid path of the oxygen generator (34); the first negative electrode electrolyte storage tank (15) is in communication with the negative electrode of the first main battery stack (5) and the liquid path of the hydrogen generator (22); The gas outlet of the oxygen generator (34) is connected to the positive electrode inlet of the fuel cell (49), and the gas outlet of the hydrogen generator (22) is connected to the negative electrode inlet of the fuel cell (49); The second positive electrode electrolyte storage tank (69) is connected to the positive electrode of the second main battery stack (63), the second negative electrode electrolyte storage tank (59) is connected to the negative electrode of the second main battery stack (63), and the outlet of the second negative electrode electrolyte storage tank (59) is also connected to the negative electrode inlet of the fuel cell (49).

2. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The outlet of the first positive electrolyte storage tank (1) is connected to the positive electrolyte inlet of the first main battery stack (5) and the liquid inlet of the oxygen generator (34) through the positive liquid inlet pipe (4), and the inlet of the first positive electrolyte storage tank (1) is connected to the positive electrolyte outlet of the first main battery stack (5) and the liquid outlet of the oxygen generator (34) through the positive liquid outlet pipe (11).

3. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The outlet of the first negative electrolyte storage tank (15) is connected to the negative electrolyte inlet of the first main battery stack (5) and the liquid inlet of the hydrogen generator (22) through a negative electrode liquid inlet pipe (18), and the inlet of the first negative electrolyte storage tank (15) is connected to the negative electrolyte outlet of the first main battery stack (5) and the liquid outlet of the hydrogen generator (22) through a negative electrode liquid outlet pipe (19).

4. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The outlet of the second negative electrolyte storage tank (59) is connected to the negative electrolyte inlet of the second main stack (63) through a negative liquid inlet branch, and the inlet of the second negative electrolyte storage tank (59) is connected to the negative electrolyte outlet of the second main stack (63) through a negative liquid outlet branch; the gas outlet of the second negative electrolyte storage tank (59) is also connected to the negative inlet of the fuel cell (49).

5. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The outlet of the second positive electrolyte storage tank (69) is connected to the positive electrolyte inlet of the second main battery stack (63) through the positive electrolyte inlet branch, and the inlet of the second positive electrolyte storage tank (69) is connected to the positive electrolyte outlet of the second main battery stack (63) through the positive electrolyte outlet branch.

6. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The oxygen generator (34) comprises a first reaction kettle and a first circulation pump (39); The first reactor is provided with a third catalytic layer (341), a first agitator (36) and a first heater (37); the first agitator (36) is arranged at the bottom of the first reactor, the first heater (37) is arranged on one side of the first agitator (36), and the third catalytic layer (341) is arranged above the first agitator (36) and the first heater (37); the first reactor is provided with a feed port (35) at the position of the third catalytic layer (341); the circulation outlet at the top of the first reactor is connected to the inlet of the first circulation pump (39), and the outlet of the first circulation pump (39) is connected to the circulation inlet at the bottom of the first reactor.

7. The dual-circuit combined operation flow battery and fuel cell system according to claim 1, characterized in that: The hydrogen generator (22) comprises a second reaction kettle and a second circulation pump (27); The second reactor is provided with a fourth catalytic layer (221), a second agitator (24) and a second heater (25); the second agitator (24) is arranged at the bottom of the second reactor, the second heater (25) is arranged on one side of the second agitator (24), and the fourth catalytic layer (221) is arranged above the second agitator (24) and the second heater (25); the second reactor is provided with a feed port (23) at the position of the fourth catalytic layer (221); the circulation outlet at the top of the second reactor is connected to the inlet of the second circulation pump (27), and the outlet of the second circulation pump (27) is connected to the circulation inlet at the bottom of the second reactor.

8. The dual-circuit combined-operation flow battery and fuel cell system according to any one of claims 1 to 7, characterized in that: An oxygen storage tank (44) is arranged between the gas outlet of the oxygen generator (34) and the positive electrode inlet of the fuel cell (49), wherein a first air pump (43) is arranged between the gas outlet of the oxygen generator (34) and the inlet of the oxygen storage tank (44), and a first humidifier (45), an external oxygen source interface (47) and an external air source interface (48) are arranged between the outlet of the oxygen storage tank (44) and the positive electrode inlet of the fuel cell (49).

9. The dual-circuit combined operation flow battery and fuel cell system according to any one of claims 1 to 7, characterized in that: A hydrogen storage tank (32) is arranged between the gas outlet of the hydrogen generator (22) and the negative electrode inlet of the fuel cell (49), wherein a sixth valve (30) and a second air pump (31) are arranged between the gas outlet of the hydrogen generator (22) and the inlet of the hydrogen storage tank (32); the gas outlet of the second negative electrode electrolyte storage tank (59) is connected to one end of a gas pipeline, and the other end of the gas pipeline is connected between the inlet of the hydrogen storage tank (32) and the sixth valve (30); a second humidifier (33) and an external hydrogen source interface (46) are arranged between the outlet of the hydrogen storage tank (32) and the negative electrode inlet of the fuel cell (49).

10. The dual-circuit combined operation flow battery and fuel cell system according to claim 9, characterized in that: It also includes an electrolyte tank (72), and a fifth three-way valve (74) is arranged between the second humidifier (33) and the external hydrogen source interface (46), the a end of the fifth three-way valve (74) is connected to the second humidifier (33), the b end of the fifth three-way valve (74) is connected to the external hydrogen source interface (46) and the negative electrode inlet of the fuel cell (49), and the c end of the fifth three-way valve (74) is connected to the electrolyte tank (72).

11. A method for operating a dual-circuit combined flow battery and fuel cell system according to any one of claims 1 to 10, characterized in that: The following steps are involved: During the charging or discharging process of the first main battery stack (5), Ce in the first positive electrode electrolyte storage tank (1) 4+ The electrolyte flows into the oxygen generator (34) to discharge and produce oxygen, and the newly generated Ce 3+ The electrolyte is returned to the first positive electrode electrolyte storage tank (1); During the charging or discharging process of the first main battery stack (5), the Cr in the first negative electrode electrolyte storage tank (15) 2+ The electrolyte flows into the hydrogen generator (22) to discharge and produce hydrogen; The oxygen produced by the oxygen generator (34) is transported to the positive electrode of the fuel cell (49) for reaction, and the hydrogen produced by the hydrogen generator (22) and the hydrogen from the second negative electrode electrolyte storage tank (59) are transported to the negative electrode of the fuel cell (49) for reaction.

Images