Vanadium redox flow battery system

Abstract

The vanadium redox flow battery system comprises a positive electrode liquid storage tank, a negative electrode liquid storage tank, an electric pile and two control mechanisms, one control mechanism is located between the positive electrode liquid storage tank and the electric pile, and the other control mechanism is located between the negative electrode liquid storage tank and the electric pile; the control mechanism comprises a valve and a circulating pump which are connected in series; the standby mechanism is connected to the control mechanism in parallel. Under the condition that the vanadium redox flow battery system does not have an unexpected condition, the electrolyte in the positive electrode liquid storage tank enters the electric pile through the control mechanism and enters the positive electrode liquid storage tank again after reacting in the electric pile, and the electrolyte in the negative electrode liquid storage tank enters the electric pile through the control mechanism and enters the negative electrode liquid storage tank again after reacting in the electric pile. And if the control mechanism breaks down, the standby mechanism intervenes and replaces the control mechanism which breaks down, and the electrolyte circulates between the electric pile and the liquid storage tank through the standby mechanism.

Description

Technical Field

[0001] The present application relates to the field of vanadium redox flow batteries, and in particular to a vanadium redox flow battery system. Background Art

[0002] An all-vanadium flow battery is a redox battery with vanadium as the active material in a circulating liquid state. The electrical energy in a vanadium battery is stored as chemical energy in a sulfuric acid electrolyte containing vanadium ions of varying valences. The electrolyte is pumped into the battery stack via an external pump and mechanically forced to circulate through a closed loop of different storage tanks and half-cells. Using a proton exchange membrane as the separator of the battery pack, the electrolyte solution flows parallel to the electrode surfaces, generating an electrochemical reaction. The current is collected and conducted by dual electrode plates, converting the chemical energy stored in the solution into electrical energy.

[0003] The existing utility model patent with patent announcement number CN208923285U discloses a modular liquid flow battery system, including a capacity module and a power module. The capacity module includes a positive electrode storage tank, a negative electrode storage tank, a positive electrode circulation pump, and a negative electrode circulation pump. The power module includes a battery stack. The liquid outlet of the positive electrode storage tank is connected to the liquid inlet of the positive electrode circulation pump. A connectable and detachable positive electrode liquid supply connector is installed on the pipeline between the liquid inlet of the positive electrode circulation pump and the positive electrode liquid inlet of the battery stack. A connectable and detachable positive electrode return connector is installed on the pipeline between the positive electrode liquid outlet of the battery stack and the liquid inlet of the positive electrode storage tank; the liquid outlet of the negative electrode storage tank is connected to the liquid inlet of the negative electrode circulation pump, and a connectable and detachable negative electrode supply connector is installed on the pipeline between the liquid inlet of the circulation pump and the negative electrode liquid inlet of the battery stack. A connectable and detachable negative electrode return connector is installed on the pipeline between the negative electrode liquid outlet of the battery stack and the liquid inlet of the negative electrode storage tank.

[0004] Regarding the aforementioned technologies, when the circulation pump or inverter fails, electrolyte circulation cannot proceed and the vanadium flow battery module must be shut down. This results in a disruption in the energy storage station's power service to users and can even affect the local power grid's power dispatch. Utility Model Content

[0005] In order to solve the above technical problems, the present application provides a vanadium flow battery system that adopts the following technical solutions:

[0006] A vanadium liquid flow battery system includes a positive electrode liquid storage tank, a negative electrode liquid storage tank, and a battery stack connected to the positive electrode liquid storage tank and the negative electrode liquid storage tank. It also includes two control mechanisms, one of which is located between the positive electrode liquid storage tank and the battery stack, and the other is located between the negative electrode liquid storage tank and the battery stack. The control mechanism includes a valve and a circulation pump, which are connected in series. The battery stack, the positive electrode liquid storage tank, and the control mechanism form a closed loop. The battery stack, the negative electrode liquid storage tank, and the control mechanism also form a closed loop. The system also includes a backup mechanism connected in parallel to the control mechanism.

[0007] Optionally, the control mechanism further includes a check valve, and the circulation pump is connected in series between the check valve and the valve.

[0008] Optionally, the backup mechanism includes a pair of backup components, which are respectively connected in parallel to the two control mechanisms, and the backup components include valves and circulation pumps, which are connected in series.

[0009] Optionally, the backup mechanism includes a three-way valve connected to the positive electrode liquid storage tank and the negative electrode liquid storage tank through pipelines, a circulation pump and a valve located between the three-way valve and the fuel cell stack, and the circulation pump and the valve are connected in series.

[0010] Optionally, it also includes a battery control system connected to the control mechanism and the backup mechanism.

[0011] Optionally, two detection devices are further included, wherein one detection device is installed at the liquid outlet of the positive electrode liquid storage tank, and the other detection device is installed at the liquid outlet of the negative electrode liquid storage tank.

[0012] Optionally, the detection device includes a flow meter and a pressure tester.

[0013] In summary, this application includes at least one of the following beneficial technical effects:

[0014] When the vanadium flow battery system is operating normally, the electrolyte in the positive electrode storage tank enters the battery stack through the control mechanism, reacts in the battery stack, and then enters the positive electrode storage tank again. The electrolyte in the negative electrode storage tank enters the battery stack through the control mechanism, reacts in the battery stack, and then enters the negative electrode storage tank again. If the control mechanism fails, the backup mechanism intervenes and replaces the failed control mechanism, and the electrolyte completes the circulation between the battery stack and the storage tank through the backup mechanism.

[0015] The system is equipped with a battery control system (BMS) and a detection device, which can realize automatic switching between the control mechanism and the backup mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of Example 1 of the present application.

[0017] Figure 2 It is a schematic diagram of the overall structure of Example 2 of the present application. DETAILED DESCRIPTION

[0018] The following is combined with Figure 1-2 This application is described in further detail.

[0019] Example 1

[0020] Reference Figure 1A vanadium liquid flow battery system includes a positive electrode liquid storage tank, a negative electrode liquid storage tank, a fuel cell stack, and a battery control system (BMS); the liquid outlet of the positive electrode liquid storage tank is connected to a detection device 1, a valve 1, a circulation pump 1, and a check valve 1 in sequence through a pipeline, the liquid outlet of the circulation pump 1 is connected to the liquid inlet of the fuel cell stack through a pipeline, and the liquid outlet of the fuel cell stack is connected to the liquid inlet of the positive electrode liquid storage tank through a pipeline, and the detection device includes a flow meter and a pressure tester installed on the pipeline.

[0021] During operation, the electrolyte flows out from the outlet of the positive electrode liquid storage tank under the action of the circulation pump 1, flows through the flow meter, pressure tester, valve 1, circulation pump 1, check valve 1 in sequence, and then enters the fuel cell stack. After reacting in the fuel cell stack, the electrolyte returns to the positive electrode liquid storage tank again.

[0022] refer to Figure 1 The system also includes a valve 2 and a circulation pump 2 connected in series. The valve 2 and the circulation pump 2 are connected in parallel on both sides of the valve 1 and the check valve 1. One side of the parallel branch formed by the valve 2 and the circulation pump 2 is connected to the detection device 1, and the other side is connected to the liquid inlet of the fuel cell stack.

[0023] During operation, when circulation pump 1 fails, the electrolyte enters the fuel cell stack through valve 2 and circulation pump 2. The electrolyte reacts in the fuel cell stack and returns to the positive electrode storage tank. Check valve 1 prevents the electrolyte from flowing back from valve 1 to the positive electrode storage tank. When valve 1 and circulation pump 1 fail, the fuel cell stack-circulation pump 2-valve 2-positive electrode storage tank-fuel cell stack is a single path.

[0024] refer to Figure 1 The liquid outlet of the negative electrode liquid storage tank is connected to the detection device 2, valve 3, circulation pump 3 and check valve 2 in sequence through a pipeline. The liquid outlet of the circulation pump 3 is connected to the liquid inlet of the fuel cell stack through a pipeline. The liquid outlet of the fuel cell stack is connected to the liquid inlet of the negative electrode liquid storage tank through a pipeline. The branch formed by the series connection of valve 4 and circulation pump 4 is connected in parallel on both sides of the circulation pump 3 and check valve 2.

[0025] During operation, the electrolyte flows from the outlet of the negative electrode liquid storage tank, passes through detection device 2, valve 3, circulation pump 3, and check valve 2, and enters the fuel cell stack. After reacting in the fuel cell stack, it returns to the negative electrode liquid storage tank. If valve 3 fails, the electrolyte circulates through valve 4 and circulation pump 4.

[0026] refer to Figure 1 The BMS is connected to detection device 1, valve 1, circulation pump 1, valve 2, circulation pump 2, detection device 2, valve 3, circulation pump 3, valve 4, circulation pump 4, check valve 1, and check valve 2 via wires or Bluetooth. The switching of the pipelines is automatically adjusted based on the measurement data of the flow meter and pressure tester.

[0027] Example 2

[0028] Reference Figure 2 A vanadium liquid flow battery system includes a positive electrode liquid storage tank, a negative electrode liquid storage tank, a fuel cell stack, and a BMS system; the positive electrode liquid storage tank, a detection device 1, a valve 5, a circulation pump 5, a check valve 3, and a fuel cell stack form a closed loop, and the connection method is the same as that of Example 1; the negative electrode liquid storage tank, a detection device 2, a valve 6, a circulation pump 6, a check valve 4, and a fuel cell stack form a closed loop, and the connection method is the same as that of Example 1.

[0029] refer to Figure 2 , also includes a three-way valve, a circulation pump 7, and a valve 7 connected in series in sequence. The other two interfaces of the three-way valve are connected to the positive electrode liquid storage tank and the negative electrode liquid storage tank through pipelines respectively. One of the connection points is located between the detection device 1 and the valve 5, and the other connection point is located between the detection device 2 and the valve 6. The valve 7 and the circulation pump 7 are located between the fuel cell stack and the three-way valve.

[0030] During operation, if circulation pump 5 fails, valve 5 closes, and the electrolyte enters the fuel cell stack through detection device 1, three-way valve, circulation pump 7, and valve 7. The electrolyte reacts in the fuel cell stack and then returns to the negative electrode liquid storage tank. Similarly, if circulation pump 6 fails, the electrolyte enters the fuel cell stack through detection device 1, three-way valve, circulation pump 7, and valve 7. The electrolyte reacts in the fuel cell stack and then returns to the negative electrode liquid storage tank.

[0031] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A vanadium flow battery system comprising a positive electrode liquid storage tank, a negative electrode liquid storage tank, and a battery stack connected to the positive electrode liquid storage tank and the negative electrode liquid storage tank, characterized in that: It also includes two control mechanisms, one of which is located between the positive electrode liquid storage tank and the battery stack, and the other is located between the negative electrode liquid storage tank and the battery stack; the control mechanism includes a valve and a circulation pump, and the valve and the circulation pump are connected in series, and the battery stack, the positive electrode liquid storage tank, and the control mechanism form a closed loop; the battery stack, the negative electrode liquid storage tank, and the control mechanism form a closed loop; and it also includes a backup mechanism connected in parallel with the control mechanism.

2. The vanadium flow battery system according to claim 1, characterized in that: The control mechanism further comprises a check valve, and the circulation pump is connected in series between the check valve and the valve.

3. The vanadium flow battery system according to claim 2, characterized in that: The backup mechanism includes a pair of backup components, and the pair of backup components are respectively connected in parallel to the two control mechanisms. The backup components include valves and circulation pumps, and the valves and circulation pumps are connected in series.

4. The vanadium flow battery system according to claim 2, characterized in that: The backup mechanism includes a three-way valve connected to the positive electrode liquid storage tank and the negative electrode liquid storage tank through pipelines, a circulation pump and a valve located between the three-way valve and the fuel cell stack, and the circulation pump and valve are connected in series.

5. The vanadium flow battery system according to any one of claims 1 to 4, characterized in that: Also included is a battery control system connected to the control mechanism and the backup mechanism.

6. The vanadium flow battery system according to claim 5, characterized in that: It also includes two detection devices, one of which is installed at the liquid outlet of the positive electrode storage tank, and the other is installed at the liquid outlet of the negative electrode storage tank.

7. The vanadium flow battery system according to claim 6, characterized in that: The detection device includes a flow meter and a pressure tester.

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