Flow battery system and temperature management method thereof

Abstract

The invention discloses a flow battery system and a temperature management method thereof, the flow battery system has indirect cyclic heating and cooling functions by arranging a two-stage heat exchange component and an auxiliary component, and the temperature of the flow battery system can be controlled by interlocking the indirect heating component or the cooling component and the auxiliary component with a pre-stack or post-stack temperature value. The preheating, heat dissipation and low-temperature protection of the positive or negative electrolyte in the standby process, the operation process and the long-time shutdown process of the flow battery system are realized; the heating component, the cooling component and the pre-stack temperature or the post-stack temperature can be subjected to double-closed-loop interlocking control, so that the heating rate or the cooling rate can be controlled. Through the implementation of the method, the uniformity of a temperature field in the electrolyte heat exchange process of the system is improved, the problems of decomposition or precipitation of active reaction substances and the like caused by overlarge local temperature difference of the electrolyte are avoided, and the adaptive capacity of the system when the load is greatly changed and the environment temperature is changed in a wide range can be enhanced; and the operation stability and reliability of the flow battery system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flow batteries, and particularly relates to a flow battery system and a temperature management method thereof. Background Art

[0002] During the operation of a flow battery, heat is generated. If heat cannot be dissipated in a timely and effective manner, the battery temperature will rise, thereby affecting the battery performance and safety. The operating temperature of a flow battery is closely related to electrochemical reactions, ionic conductivity, ionic transmembrane transport rate, and electrolyte viscosity, etc. Increasing the temperature can increase the reaction rate and promote the reaction kinetics in the electrochemical reaction. At the same time, high temperature will also reduce the electrolyte viscosity, thereby improving the transport efficiency of ions from the bulk to the electrode surface and reducing the concentration polarization potential. However, when the temperature exceeds a certain range, it will have a greater adverse impact on the battery, such as accelerating the side reaction, resulting in a decrease in Coulomb efficiency; enhancing the diffusion ability of ions through the separator, exacerbating capacity decay; causing precipitation of reactants in the electrolyte, resulting in flow channel blockage, covering the electrodes and the separator, increasing the power consumption of the delivery pump, and causing battery failure, etc. In addition, continuously high temperature will also accelerate the aging of materials such as internal electrodes and separators in the battery, thereby shortening the service life of the battery. Therefore, temperature management is of great significance for maintaining the stable operation of a flow battery.

[0003] Currently, the temperature management of flow batteries often adopts the method of directly heating or cooling the electrolyte, which has the following disadvantages: on the one hand, the electrolyte is sensitive to temperature. Directly heating or cooling the electrolyte easily causes a large local temperature difference in the electrolyte, making the local electrolyte temperature field uneven, resulting in problems such as local electrolyte thermal decomposition or precipitation of active substances at low temperature, and also having a certain impact on system energy consumption, system efficiency, and system cost. On the other hand, a flow battery generally needs to adjust the output power in response to load changes during the energy storage process. When the output power changes, the generated heat will also change, and the heat load in the temperature management process needs to be adjusted in real time. In addition, the ambient temperature will directly or indirectly affect the temperature management efficiency and cost of the flow battery. When the ambient temperature is high, the heat dissipation temperature difference is small, the heat dissipation efficiency is low, and the heat dissipation energy consumption is high; when the ambient temperature is too low, the heating energy consumption is high. Therefore, the temperature management process of a flow battery needs to make a real-time response to wide-range load changes and overcome the heat balance problem caused by wide-range ambient temperature changes, which poses certain difficulties to the system temperature management. Summary of the Invention

[0004] The purpose of the present invention is to provide a flow battery system and a temperature management method thereof, which are beneficial to improving the uniformity of the temperature field in the electrolyte heat exchange process of the system, avoiding problems such as decomposition or precipitation of active reaction substances caused by excessive local temperature difference of the electrolyte, enhancing the adaptability of the system to large load variations and wide-range ambient temperature changes, and improving the operation stability and reliability of the flow battery system.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A flow battery system, comprising a battery stack unit, a positive electrolyte delivery unit, a negative electrolyte delivery unit, a positive temperature management unit, a negative temperature management unit and a control unit;

[0007] The battery stack unit includes a battery stack, a power supply and a load respectively electrically connected to the battery stack, a positive electrolyte inlet, a positive electrolyte outlet, a negative electrolyte inlet and a negative electrolyte outlet provided on the battery stack, a positive electrolyte inlet pipe with one end communicating with the positive electrolyte inlet, a positive electrolyte outlet pipe with one end communicating with the positive electrolyte outlet, a negative electrolyte inlet pipe with one end communicating with the negative electrolyte inlet, a negative electrolyte outlet pipe with one end communicating with the negative electrolyte outlet, a first valve and a positive stack front temperature sensor provided on the positive electrolyte inlet pipe, a positive stack rear temperature sensor provided on the positive electrolyte outlet pipe, a second valve and a negative stack front temperature sensor provided on the negative electrolyte inlet pipe, a negative stack rear temperature sensor provided on the negative electrolyte outlet pipe, a positive electrolyte bypass with both ends respectively communicating with the positive electrolyte inlet pipe and the positive electrolyte outlet pipe, a negative electrolyte bypass with both ends respectively communicating with the negative electrolyte inlet pipe and the negative electrolyte outlet pipe, a third valve provided on the positive electrolyte bypass, and a fourth valve provided on the negative electrolyte bypass;

[0008] The positive electrolyte delivery unit includes a positive electrolyte storage tank, a positive electrolyte delivery pump and a positive temperature management bypass connected in sequence, a fifth valve provided on the positive temperature management bypass, and the positive temperature management bypass communicates with the positive electrolyte inlet pipe; the positive electrolyte storage tank communicates with the positive electrolyte delivery pump through its liquid outlet, and the positive electrolyte storage tank communicates with the positive electrolyte outlet pipe through its liquid inlet;

[0009] The negative electrolyte delivery unit includes a negative electrolyte storage tank, a negative electrolyte delivery pump and a negative temperature management bypass connected in sequence, a sixth valve provided on the negative temperature management bypass, and the negative temperature management bypass communicates with the negative electrolyte inlet pipe; the negative electrolyte storage tank communicates with the negative electrolyte delivery pump through its liquid outlet, and the negative electrolyte storage tank communicates with the negative electrolyte outlet pipe through its liquid inlet;

[0010] The positive electrode temperature management unit includes a positive electrode heat exchanger, a positive electrode cooler, a positive electrode auxiliary circulation pump, and a positive electrode heater. The positive electrode heat exchanger includes a positive electrode electrolyte flow branch and a positive electrode heat transfer medium flow branch. The positive electrode electrolyte flow branch is connected in parallel with the positive electrode temperature management bypass, and a seventh valve is provided on the positive electrode electrolyte flow branch. The positive electrode heat transfer medium flow branch is sequentially connected to the positive electrode cooler, the positive electrode auxiliary circulation pump, and the positive electrode heater.

[0011] The negative electrode temperature management unit includes a negative electrode heat exchanger, a negative electrode cooler, a negative electrode auxiliary circulation pump, and a negative electrode heater. The negative electrode heat exchanger includes a negative electrode electrolyte flow branch and a negative electrode heat transfer medium flow branch. The negative electrode electrolyte flow branch is connected in parallel with the negative electrode temperature management bypass, and an eighth valve is provided on the negative electrode electrolyte flow branch. The negative electrode heat transfer medium flow branch is sequentially connected to the negative electrode cooler, the negative electrode auxiliary circulation pump, and the negative electrode heater.

[0012] The control unit is configured to respectively receive the sensor signals of the positive electrode stack front temperature sensor, the positive electrode stack rear temperature sensor, the negative electrode stack front temperature sensor, and the negative electrode stack rear temperature sensor, and is configured to respectively control the opening and closing and the opening degree of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the eighth valve. It is also configured to respectively control the output power of the positive electrode electrolyte delivery pump, the negative electrode electrolyte delivery pump, the positive electrode auxiliary circulation pump, and the negative electrode auxiliary circulation pump.

[0013] Preferably, the positive electrode temperature management unit further includes a positive electrode auxiliary liquid storage tank communicated with the positive electrode heat transfer medium flow branch. The negative electrode temperature management unit further includes a negative electrode auxiliary liquid storage tank communicated with the negative electrode heat transfer medium flow branch.

[0014] Preferably, the positive electrode cooler includes a positive electrode coolant flow branch and a ninth valve provided on the positive electrode coolant flow branch. The control unit is further configured to control the opening and closing and the opening degree of the ninth valve. The negative electrode cooler includes a negative electrode coolant flow branch and a tenth valve provided on the negative electrode coolant flow branch. The control unit is further configured to control the opening and closing and the opening degree of the tenth valve.

[0015] A method for preheating the positive electrolyte before the operation of a flow battery system, which is implemented by the above-mentioned flow battery system, includes: receiving a positive electrolyte preheating instruction, determining that the power supply and the load are in an off-load state, opening the third valve and the seventh valve, closing the first valve and the fifth valve, adjusting the speed of the positive electrolyte delivery pump to a first set value, adjusting the speed of the positive auxiliary circulation pump to a second set value, detecting the current value of the positive inlet stack temperature through the positive stack front temperature sensor, and setting the temperature to be reached for the positive electrolyte preheating as the target value:

[0016] In the first step, it is judged whether the current value of the positive inlet stack temperature is less than its target value. If so, the heating power of the positive heater is controlled to be in linkage with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0017] In the second step, it is judged whether the current value of the positive inlet stack temperature is greater than or equal to its target value. If so, the preheating of the positive electrolyte is completed. If not, return to the first step of judgment.

[0018] A method for preheating the negative electrolyte before the operation of a flow battery system, which is implemented by the above-mentioned flow battery system, includes: receiving a negative electrolyte preheating instruction, determining that the power supply and the load are in an off-load state, opening the fourth valve and the eighth valve, closing the second valve and the sixth valve, adjusting the speed of the negative electrolyte delivery pump to a third set value, adjusting the speed of the negative auxiliary circulation pump to a fourth set value, detecting the current value of the negative inlet stack temperature through the negative stack front temperature sensor, and setting the temperature to be reached for the negative electrolyte preheating as the target value:

[0019] In the first step, it is judged whether the current value of the negative inlet stack temperature is less than its target value. If so, the heating power of the negative heater is controlled to be in linkage with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0020] In the second step, it is judged whether the current value of the negative inlet stack temperature is greater than or equal to its target value. If so, the preheating of the negative electrolyte is completed. If not, return to the first step of judgment.

[0021] A method for cooling the positive electrolyte after the shutdown of a flow battery system, which is implemented by the above-mentioned flow battery system, includes: receiving a positive electrolyte cooling instruction, determining that the power supply and the load are in an off-load state, opening the third valve and the seventh valve, closing the first valve and the fifth valve, adjusting the speed of the positive electrolyte delivery pump to a fifth set value, adjusting the speed of the positive auxiliary circulation pump to a sixth set value, detecting the current value of the positive inlet stack temperature through the positive stack front temperature sensor, and setting the temperature to be reached for the positive electrolyte cooling as the target value:

[0022] In the first step, it is judged whether the current value of the positive electrode inlet stack temperature is greater than its target value. If so, the cooling power of the positive electrode cooler is controlled to be interlocked with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0023] In the second step, it is judged whether the current value of the positive electrode inlet stack temperature is less than or equal to its target value. If so, the cooling of the positive electrode electrolyte is completed. If not, return to the first step of judgment.

[0024] A method for cooling the negative electrode electrolyte after the shutdown of a flow battery system, which is realized by the above-mentioned flow battery system, includes: receiving a negative electrode electrolyte cooling instruction, determining that the power supply and the load are in a disconnection state, opening the fourth valve and the eighth valve, closing the second valve and the sixth valve, adjusting the rotation speed of the negative electrode electrolyte delivery pump to the seventh set value, adjusting the rotation speed of the negative electrode auxiliary circulation pump to the eighth set value, detecting the current value of the negative electrode inlet stack temperature through the negative electrode stack front temperature sensor, and setting the temperature to be reached for cooling the negative electrode electrolyte as the target value:

[0025] In the first step, it is judged whether the current value of the negative electrode inlet stack temperature is greater than its target value. If so, the cooling power of the negative electrode cooler is controlled to be interlocked with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0026] In the second step, it is judged whether the current value of the negative electrode inlet stack temperature is less than or equal to its target value. If so, the cooling of the negative electrode electrolyte is completed. If not, return to the first step of judgment.

[0027] A method for temperature management in the operating state of a flow battery system, which is realized by the above-mentioned flow battery system, includes: collecting the voltage parameters and current parameters of the battery stack, as well as the flow rate parameters and temperature parameters of the positive electrode electrolyte, setting the protection upper limit values of each parameter, setting the flow rate target value of the positive electrode electrolyte according to the planned load current of the battery stack, interlocking the flow rate of the positive electrode electrolyte with the rotation speed of the positive electrode electrolyte delivery pump, implementing PID control, and judging whether temperature control is required:

[0028] If not, close the seventh valve, open the fifth valve, and respectively detect the current value of the positive electrode stack front temperature and the current value of the positive electrode stack rear temperature through the positive electrode stack front temperature sensor and the positive electrode stack rear temperature sensor, and judge whether at least one of the two current values is higher than the corresponding temperature protection upper limit value: If so, enter the shutdown process. If not, return to the previous step to continue detection;

[0029] If so, close the fifth valve, open the seventh valve, and detect the current value of the positive electrode stack rear temperature through the positive electrode stack rear temperature sensor, and set the target value of the positive electrode stack rear temperature:

[0030] In the first step, it is judged whether the current value of the temperature behind the positive electrode stack is greater than its target value. If so, the cooling power of the positive electrode cooler is controlled to be linked with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0031] In the second step, it is judged whether the current value of the temperature behind the positive electrode stack is less than its target value. If so, the heating power of the positive electrode heater is controlled to be linked with the current value, and PID control is implemented, and then the third step of judgment is entered. If not, the third step of judgment is directly entered;

[0032] In the third step, it is judged whether the current value of the temperature behind the positive electrode stack is equal to its target value. If so, the current states of the positive electrode cooler and the positive electrode heater are maintained. If not, the first step of judgment is returned to.

[0033] A method for temperature management in the operating state of a flow battery system, implemented by the above flow battery system, includes: collecting voltage parameters and current parameters of the battery stack, as well as flow parameters and temperature parameters of the negative electrode electrolyte, setting protection upper limit values for each parameter, setting a flow target value for the negative electrode electrolyte according to the planned load current of the battery stack, linking the flow of the negative electrode electrolyte with the rotation speed of the negative electrode electrolyte delivery pump, implementing PID control, and judging whether temperature control is required:

[0034] If not, the eighth valve is closed, the sixth valve is opened, and the current value of the temperature in front of the negative electrode stack and the current value of the temperature behind the negative electrode stack are respectively detected through the temperature sensor in front of the negative electrode stack and the temperature sensor behind the negative electrode stack, and it is judged whether at least one of the two current values is higher than the corresponding temperature protection upper limit value: If so, the shutdown process is entered. If not, the previous step is returned to for continuous detection;

[0035] If so, the sixth valve is closed, the eighth valve is opened, and the current value of the temperature behind the negative electrode stack is detected through the temperature sensor behind the negative electrode stack, and the target value of the temperature behind the negative electrode stack is set:

[0036] In the first step, it is judged whether the current value of the temperature behind the negative electrode stack is greater than its target value. If so, the cooling power of the negative electrode cooler is controlled to be linked with the current value, and PID control is implemented, and then the second step of judgment is entered. If not, the second step of judgment is directly entered;

[0037] In the second step, it is judged whether the current value of the temperature behind the negative electrode stack is less than its target value. If so, the heating power of the negative electrode heater is controlled to be linked with the current value, and PID control is implemented, and then the third step of judgment is entered. If not, the third step of judgment is directly entered;

[0038] In the third step, determine whether the current value of the temperature after the negative electrode stack is equal to its target value. If it is, maintain the current states of the negative electrode cooler and the negative electrode heater; if not, return to the first step for judgment.

[0039] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The flow battery system and its temperature management method of the present invention have indirect circulation heating and cooling functions by setting up secondary heat exchange components and auxiliary components. It can achieve preheating, heat dissipation, and low-temperature protection of the positive or negative electrode electrolytes during the standby process, operation process, and long-term shutdown process of the flow battery system by interlocking the indirect heating component or cooling component and the auxiliary component with the temperature value before or after the stack. It can achieve control of the heating or cooling rate by performing double-closed-loop interlocking control of the heating component and the cooling component with the temperature before or after the stack. Implementing the present invention is beneficial to improving the uniformity of the temperature field in the electrolyte heat exchange process of the system, avoiding problems such as decomposition or precipitation of active reaction substances caused by excessive local temperature differences in the electrolyte, enhancing the adaptability of the system under large load variations and wide range of ambient temperature changes, and improving the operation stability and reliability of the flow battery system. Brief Description of the Drawings

[0040] Appendix Figure 1 It is a schematic structural diagram of a flow battery system according to a specific embodiment of the present invention;

[0041] Appendix Figure 2 It is a flowchart of the preheating process of the positive electrode electrolyte in the standby state of the flow battery system according to a specific embodiment of the present invention;

[0042] Appendix Figure 3 It is a flowchart of the temperature reduction process of the positive electrode electrolyte in the shutdown state of the flow battery system according to a specific embodiment of the present invention;

[0043] Appendix Figure 4 It is a flowchart of the positive electrode temperature management process in the operation state of the flow battery system according to a specific embodiment of the present invention.

[0044] Wherein: 100, battery stack unit;

[0045] 101, Battery stack; 102, Power supply; 103, Load; 104, Voltage collector; 105, Positive electrolyte inlet; 106, Positive electrolyte outlet; 107, Negative electrolyte inlet; 108, Negative electrolyte outlet; 109, Positive electrolyte inlet pipe; 110, Positive electrolyte outlet pipe; 111, Negative electrolyte inlet pipe; 112, Negative electrolyte outlet pipe; 113, First valve; 114, Temperature sensor in front of the positive stack; 115, Temperature sensor behind the positive stack; 116, Second valve; 117, Temperature sensor in front of the negative stack; 118, Temperature sensor behind the negative stack; 119, Positive electrolyte bypass; 120, Negative electrolyte bypass; 121, Third valve; 122, Fourth valve;

[0046] 200, Positive electrolyte delivery unit;

[0047] 201, Positive electrolyte storage tank; 202, Positive electrolyte delivery pump; 203, Positive temperature management bypass; 204, Fifth valve;

[0048] 300, Negative electrolyte delivery unit;

[0049] 301, Negative electrolyte storage tank; 302, Negative electrolyte delivery pump; 303, Negative temperature management bypass; 304, Sixth valve;

[0050] 400, Positive temperature management unit;

[0051] 401, Positive heat exchanger; 402, Positive cooler; 403, Positive auxiliary circulation pump; 404, Positive heater; 405, Positive electrolyte flow branch; 406, Positive heat transfer medium flow branch; 407, Seventh valve; 408, Positive auxiliary liquid storage tank; 409, Positive coolant flow branch; 410, Ninth valve;

[0052] 500, Negative temperature management unit;

[0053] 501, Negative heat exchanger; 502, Negative cooler; 503, Negative auxiliary circulation pump; 504, Negative heater; 505, Negative electrolyte flow branch; 506, Negative heat transfer medium flow branch; 507, Eighth valve; 508, Negative auxiliary liquid storage tank; 509, Negative coolant flow branch; 510, Tenth valve;

[0054] 600, Control unit. Detailed implementation manners

[0055] The technical solutions of the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0056] In the following text, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the accompanying drawings and the description are regarded as exemplary in nature and not restrictive.

[0057] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "length", "inside", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0058] Furthermore, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0059] In the embodiments of the present invention, unless otherwise clearly specified and limited, terms such as "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0060] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0061] The following disclosure provides many different embodiments or examples for implementing different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the embodiments of the present invention. In addition, the embodiments of the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0062] See Figure 1 As shown, this embodiment provides a flow battery system, including a battery stack unit 100, a positive electrolyte delivery unit 200, a negative electrolyte delivery unit 300, a positive temperature management unit 400, a negative temperature management unit 500, and a control unit 600.

[0063] The battery stack unit 100 includes a battery stack 101, a power supply 102, a load 103, and a voltage collector 104 that are electrically connected to the battery stack 101 respectively, a positive electrolyte inlet 105, a positive electrolyte outlet 106, a negative electrolyte inlet 107, and a negative electrolyte outlet 108 provided on the battery stack 101, a positive electrolyte inlet pipe 109 with one end communicating with the positive electrolyte inlet 105, a positive electrolyte outlet pipe 110 with one end communicating with the positive electrolyte outlet 106, a negative electrolyte inlet pipe 111 with one end communicating with the negative electrolyte inlet 107, a negative electrolyte outlet pipe 112 with one end communicating with the negative electrolyte outlet 108, a first valve 113 and a positive stack front temperature sensor 114 provided on the positive electrolyte inlet pipe 109, a positive stack rear temperature sensor 115 provided on the positive electrolyte outlet pipe 110, a second valve 116 and a negative stack front temperature sensor 117 provided on the negative electrolyte inlet pipe 111, a negative stack rear temperature sensor 118 provided on the negative electrolyte outlet pipe 112, a positive electrolyte bypass 119 with both ends communicating with the positive electrolyte inlet pipe 109 and the positive electrolyte outlet pipe 110 respectively, a negative electrolyte bypass 120 with both ends communicating with the negative electrolyte inlet pipe 111 and the electrolyte outlet pipe respectively, a third valve 121 provided on the positive electrolyte bypass 119, and a fourth valve 122 provided on the negative electrolyte bypass 120. The first valve 113 is in series with the battery stack 101 and then in parallel with the third valve 121, and the second valve 116 is in series with the battery stack 101 and then in parallel with the fourth valve 122.

[0064] Among them:

[0065] The power supply 102 is connected to the high-voltage port of the battery stack 101, the load 103 is connected to the high-voltage interface of the battery stack 101, and the voltage collector 104 is connected to the cell voltage interface of the battery stack 101;

[0066] The power supply 102 is used to supply electrical energy to the battery stack 101 during the charging process, the load 103 is used to consume the electrical energy generated by the battery stack 101 during the discharging process, and the voltage collector 104 is used to transmit the total voltage of the battery stack 101 or the voltage of each battery in real time during the operation of the battery stack 101;

[0067] The positive stack front temperature sensor 114 is used to detect the temperature in the positive electrolyte inlet pipe 109, the positive stack rear temperature sensor 115 is used to detect the temperature in the positive electrolyte outlet pipe 110, the negative stack front temperature sensor 117 is used to detect the temperature in the negative electrolyte inlet pipe 111, and the negative stack rear temperature sensor 118 is used to detect the temperature in the negative electrolyte outlet pipe 112;

[0068] The first valve 113, the second valve 116, the third valve 121 and the fourth valve 122 are respectively used to control the on / off and flow rate of the corresponding pipelines.

[0069] The positive electrolyte delivery unit 200 includes a positive electrolyte storage tank 201, a positive electrolyte delivery pump 202 and a positive temperature management bypass 203 connected in sequence, a fifth valve 204 provided on the positive temperature management bypass 203, and the positive temperature management bypass 203 is connected to the positive electrolyte inlet pipe 109; the positive electrolyte storage tank 201 is connected to the positive electrolyte delivery pump 202 through its liquid outlet, and the positive electrolyte storage tank 201 is connected to the positive electrolyte outlet pipe 110 through its liquid inlet.

[0070] Among them:

[0071] The rotation speed of the positive electrolyte delivery pump 202 is adjusted by motor frequency conversion, which is used to control the flow rate of the positive electrolyte entering the stack, and the flow rate can be adjusted according to the current or voltage or power of the power supply 102 or the load 103;

[0072] The fifth valve 204 is used to control the on / off and flow rate of the positive temperature management bypass 203.

[0073] The negative electrolyte delivery unit 300 includes a negative electrolyte storage tank 301, a negative electrolyte delivery pump 302 and a negative temperature management bypass 303 connected in sequence, a sixth valve 304 provided on the negative temperature management bypass 303, and the negative temperature management bypass 303 is connected to the negative electrolyte inlet pipe 111; the negative electrolyte storage tank 301 is connected to the negative electrolyte delivery pump 302 through its liquid outlet, and the negative electrolyte storage tank 301 is connected to the negative electrolyte outlet pipe 112 through its liquid inlet.

[0074] Among them:

[0075] The rotation speed of the negative electrode electrolyte delivery pump 302 is adjusted by motor frequency conversion to control the flow rate of the negative electrode electrolyte entering the reactor, and the flow rate can be adjusted according to the current or voltage or power of the power supply 102 or the load 103.

[0076] The sixth valve 304 is used to control the on / off and flow rate of the negative electrode temperature management bypass 303.

[0077] The positive electrode temperature management unit 400 includes a positive electrode heat exchanger 401, a positive electrode cooler 402, a positive electrode auxiliary circulation pump 403, and a positive electrode heater 404. The positive electrode heat exchanger 401 includes a positive electrode electrolyte flow branch 405 and a positive electrode heat exchange medium flow branch 406. The positive electrode electrolyte flow branch 405 is connected in parallel with the positive electrode temperature management bypass 203, and a seventh valve 407 is provided on the positive electrode electrolyte flow branch 405; the positive electrode heat exchange medium flow branch 406 is sequentially connected to the positive electrode cooler 402, the positive electrode auxiliary circulation pump 403, and the positive electrode heater 404.

[0078] Among them: The positive electrode auxiliary circulation pump 403 can be set with a speed regulation function, and by adjusting the speed, the flow rate of the heat exchange medium can be adjusted accordingly.

[0079] The seventh valve 407 is used to control the on / off and flow rate of the positive electrode electrolyte flow branch 405.

[0080] In this embodiment, the positive electrode temperature management unit 400 further includes a positive electrode auxiliary liquid storage tank 408 connected to the positive electrode heat exchange medium flow branch 406. The liquid outlet pipe of the positive electrode auxiliary liquid storage tank 408 is connected between the positive electrode cooler 402 and the positive electrode auxiliary circulation pump 403 in a T-shaped connection for self-adaptive adjustment of the thermal expansion and contraction of the heat exchange medium.

[0081] In this embodiment, the positive electrode cooler 402 includes a positive electrode coolant flow branch 409 and a ninth valve 410 provided on the positive electrode coolant flow branch 409. The ninth valve 410 is used to control the on / off and flow rate of the positive electrode coolant flow branch 409.

[0082] The negative electrode temperature management unit 500 includes a negative electrode heat exchanger 501, a negative electrode cooler 502, a negative electrode auxiliary circulation pump 503, and a negative electrode heater 504. The negative electrode heat exchanger 501 includes a negative electrode electrolyte flow branch 505 and a negative electrode heat exchange medium flow branch 506. The negative electrode electrolyte flow branch 505 is connected in parallel with the negative electrode temperature management bypass 303, and an eighth valve 507 is provided on the negative electrode electrolyte flow branch 505; the negative electrode heat exchange medium flow branch 506 is sequentially connected to the negative electrode cooler 502, the negative electrode auxiliary circulation pump 503, and the negative electrode heater 504.

[0083] Among them: The negative electrode auxiliary circulation pump 503 can be set with a speed regulation function, and by adjusting the speed, the flow rate of the heat exchange medium can be adjusted accordingly.

[0084] The eighth valve 507 is used to control the on / off and flow rate of the negative electrolyte flow branch 505.

[0085] In this embodiment, the negative temperature management unit 500 further includes a negative auxiliary liquid storage tank 508 communicated with the negative heat exchange medium flow branch 506. The liquid outlet pipe of the negative auxiliary liquid storage tank 508 is connected between the negative cooler 502 and the negative auxiliary circulation pump 503, and is connected in a T shape for self-adaptive adjustment of the thermal expansion and contraction of the heat exchange medium.

[0086] In this embodiment, the negative cooler 502 includes a negative coolant flow branch 509 and a tenth valve 510 provided on the negative coolant flow branch 509. The tenth valve 510 is used to control the on / off and flow rate of the negative coolant flow branch 509.

[0087] The control unit 600 is configured to receive the sensor signals of the positive stack front temperature sensor 114, the positive stack rear temperature sensor 115, the negative stack front temperature sensor 117, and the negative stack rear temperature sensor 118 respectively, and is used to control the on / off and opening degrees of the first valve 113, the second valve 116, the third valve 121, the fourth valve 122, the fifth valve 204, the sixth valve 304, the seventh valve 407, and the eighth valve 507 respectively; and is further used to control the output powers of the positive electrolyte delivery pump 202, the negative electrolyte delivery pump 302, the positive auxiliary circulation pump 403, and the negative auxiliary circulation pump 503 respectively.

[0088] See Figure 2 As shown, a method for preheating the positive electrolyte before operation of a flow battery system is implemented by the above-mentioned flow battery system, and includes the following steps:

[0089] S11: Receive the positive electrolyte preheating instruction and determine that the power supply 102 and the load 103 are in the off-load state;

[0090] S12: Open the third valve 121 and the seventh valve 407, and close the first valve 113 and the fifth valve 204;

[0091] S13: Adjust the rotation speed of the positive electrolyte delivery pump 202 to the first set value, and adjust the rotation speed of the positive auxiliary circulation pump 403 to the second set value;

[0092] S14: Detect the current value of the positive stack inlet temperature through the positive stack front temperature sensor 114, and set the temperature required for positive electrolyte preheating as the target value;

[0093] S15: First, judge whether the current value of the positive stack inlet temperature is less than its target value. If so, execute S16; if not, execute S17;

[0094] S16: Link the heating power of the positive electrode heater 404 with the current value and implement PID control;

[0095] S17: In the second step, determine whether the current value of the positive electrode inlet stack temperature is greater than or equal to its target value. If so, the preheating of the positive electrode electrolyte is completed; if not, execute S15.

[0096] A method for preheating the negative electrode electrolyte before the operation of a flow battery system, which is implemented by the above-mentioned flow battery system, includes the following steps:

[0097] S11: Receive the negative electrode electrolyte preheating instruction and determine that the power supply 102 and the load 103 are in the off-load state;

[0098] S12: Open the fourth valve 122 and the eighth valve 507, and close the second valve 116 and the sixth valve 304;

[0099] S13: Adjust the rotation speed of the negative electrode electrolyte delivery pump 302 to the third set value, and adjust the rotation speed of the negative electrode auxiliary circulation pump 503 to the fourth set value;

[0100] S14: Detect the current value of the negative electrode inlet stack temperature through the negative electrode stack front temperature sensor 117, and set the temperature to be reached for the preheating of the negative electrode electrolyte as the target value;

[0101] S15: In the first step, determine whether the current value of the negative electrode inlet stack temperature is less than its target value. If so, execute S16; if not, execute S17;

[0102] S16: Link the heating power of the negative electrode heater 504 with the current value and implement PID control;

[0103] S17: In the second step, determine whether the current value of the negative electrode inlet stack temperature is greater than or equal to its target value. If so, the preheating of the negative electrode electrolyte is completed; if not, execute S15.

[0104] See Figure 3 As shown in the figure, a method for cooling the positive electrode electrolyte after the shutdown of a flow battery system, which is implemented by the above-mentioned flow battery system, includes the following steps:

[0105] S21: Receive the positive electrode electrolyte cooling instruction and determine that the power supply 102 and the load 103 are in the off-load state;

[0106] S22: Open the third valve 121 and the seventh valve 407, and close the first valve 113 and the fifth valve 204;

[0107] S23: Adjust the rotation speed of the positive electrode electrolyte delivery pump 202 to the fifth set value, and adjust the rotation speed of the positive electrode auxiliary circulation pump 403 to the sixth set value;

[0108] S24: Detect the current value of the positive electrode inlet temperature through the positive electrode stack front temperature sensor 114, and set the temperature to be reached for positive electrode electrolyte cooling as the target value;

[0109] S25: In the first step, determine whether the current value of the positive electrode inlet temperature is greater than its target value. If so, execute S26; if not, execute S27;

[0110] S26: Control the cooling power of the positive electrode cooler 402 to be interlocked with the current value and implement PID control; in this embodiment, control the opening degree of the ninth valve 410 to be interlocked with the current value and implement PID control;

[0111] S27: In the second step, determine whether the current value of the positive electrode inlet temperature is less than or equal to its target value. If so, the positive electrode electrolyte cooling is completed; if not, execute S25.

[0112] A method for cooling the negative electrode electrolyte after the shutdown of a flow battery system, implemented through the above flow battery system, includes the following steps:

[0113] S21: Receive the negative electrode electrolyte cooling instruction and determine that the power supply 102 and the load 103 are in the off-load state;

[0114] S22: Open the fourth valve 122 and the eighth valve 507, and close the second valve 116 and the sixth valve 304;

[0115] S23: Adjust the rotation speed of the negative electrode electrolyte delivery pump 302 to the seventh set value, and adjust the rotation speed of the negative electrode auxiliary circulation pump 503 to the eighth set value;

[0116] S24: Detect the current value of the negative electrode inlet temperature through the negative electrode stack front temperature sensor 117, and set the temperature to be reached for negative electrode electrolyte cooling as the target value;

[0117] S25: In the first step, determine whether the current value of the negative electrode inlet temperature is greater than its target value. If so, execute S26; if not, execute S27;

[0118] S26: Control the cooling power of the negative electrode cooler 502 to be interlocked with the current value and implement PID control; in this embodiment, control the opening degree of the tenth valve 510 to be interlocked with the current value and implement PID control;

[0119] S27: In the second step, determine whether the current value of the negative electrode inlet temperature is less than or equal to its target value. If so, the negative electrode electrolyte cooling is completed; if not, execute S25.

[0120] See Figure 4 As shown in, a method for temperature management in the operating state of a flow battery system, implemented through the above flow battery system, includes the following steps:

[0121] S310: Collect the voltage parameters and current parameters of the battery stack 101, as well as the flow rate parameters and temperature parameters of the positive electrolyte, and set the protection upper limit values for each parameter;

[0122] S320: Set the flow rate target value of the positive electrolyte according to the planned load current of the battery stack 101, interlock the flow rate of the positive electrolyte with the rotation speed of the positive electrolyte delivery pump 202, and implement PID control;

[0123] S330: Determine whether temperature control is required; in this embodiment, determine whether the system can achieve automatic temperature balance according to the power of the battery stack 101. If so, temperature control is not required; if not, temperature control is required:

[0124] S341: When temperature control is not required, close the third valve 121, the seventh valve 407, and the ninth valve 410, and open the first valve 113 and the fifth valve 204;

[0125] S342: Detect the current value of the temperature in front of the positive electrode stack and the current value of the temperature behind the positive electrode stack through the temperature sensor in front of the positive electrode stack and the temperature sensor 115 behind the positive electrode stack respectively;

[0126] S343: Determine whether at least one of the two current values is higher than the corresponding temperature protection upper limit value. If so, execute S344; if not, execute S342;

[0127] S344: Enter the shutdown process;

[0128] S351: When temperature control is required, close the third valve 121 and the fifth valve 204, and open the first valve 113, the seventh valve 407, and the ninth valve 410;

[0129] S352: Detect the current value of the temperature behind the positive electrode stack through the temperature sensor 115 behind the positive electrode stack, and set the target value of the temperature behind the positive electrode stack;

[0130] S353: In the first step, determine whether the current value of the temperature behind the positive electrode stack is greater than its target value. If so, execute S354; if not, execute S355;

[0131] S354: Control the cooling power of the positive electrode cooler 402 to be interlocked with the current value, and implement PID control; in this embodiment, control the opening degree of the ninth valve 410 to be interlocked with the current value, and implement PID control;

[0132] S355: In the second step, determine whether the current value of the temperature behind the positive electrode stack is less than its target value. If so, execute S356; if not, execute S357;

[0133] S356: Control the heating power of the positive electrode heater 404 to be interlocked with the current value, and implement PID control;

[0134] S357: In the third step, determine whether the current value of the temperature after the positive electrode stack is equal to its target value. If so, execute S358; if not, execute S352.

[0135] S358: Maintain the current states of the positive electrode cooler 402 and the positive electrode heater 404.

[0136] During the operation of the flow battery, since the positive electrode electrolyte and the negative electrode electrolyte exchange heat through a partition wall inside the battery stack 101, the temperature management of the positive electrode electrolyte actually also completes the temperature management of the negative electrode electrolyte.

[0137] A method for temperature management in the operating state of a flow battery system, implemented by the above-mentioned flow battery system, includes the following steps:

[0138] S310: Collect the voltage parameters and current parameters of the battery stack 101, as well as the flow rate parameters and temperature parameters of the negative electrode electrolyte, and set the protection upper limit values for each parameter.

[0139] S320: Set the flow rate target value of the negative electrode electrolyte according to the planned load current of the battery stack 101, interlock the flow rate of the negative electrode electrolyte with the rotation speed of the negative electrode electrolyte delivery pump 302, and implement PID control.

[0140] S330: Determine whether temperature control is required; in this embodiment, determine whether the system can automatically balance the temperature according to the power of the battery stack 101. If so, no temperature control is required; if not, temperature control is required:

[0141] S341: When no temperature control is required, close the fourth valve 122, the eighth valve 507, and the tenth valve 510, and open the second valve 116 and the sixth valve 304.

[0142] S342: Detect the current value of the temperature before the negative electrode stack and the current value of the temperature after the negative electrode stack respectively through the temperature sensor before the negative electrode stack and the temperature sensor 118 after the negative electrode stack.

[0143] S343: Determine whether at least one of the two current values is higher than the corresponding temperature protection upper limit value. If so, execute S344; if not, execute S342.

[0144] S344: Enter the shutdown process.

[0145] S351: When temperature control is required, close the fourth valve 122 and the sixth valve 304, and open the second valve 116, the eighth valve 507, and the tenth valve 510.

[0146] S352: Detect the current value of the temperature behind the negative electrode stack through the temperature sensor 118 behind the negative electrode stack, and set the target value of the temperature behind the negative electrode stack;

[0147] S353: In the first step, determine whether the current value of the temperature behind the negative electrode stack is greater than its target value. If so, execute S354; if not, execute S355;

[0148] S354: Control the cooling power of the negative electrode cooler 502 to be interlocked with the current value and implement PID control; in this embodiment, control the opening degree of the tenth valve 510 to be interlocked with the current value and implement PID control;

[0149] S355: In the second step, determine whether the current value of the temperature behind the negative electrode stack is less than its target value. If so, execute S356; if not, execute S357;

[0150] S356: Control the heating power of the negative electrode heater 504 to be interlocked with the current value and implement PID control.

[0151] S357: In the third step, determine whether the current value of the temperature behind the negative electrode stack is equal to its target value. If so, execute S358; if not, execute S352;

[0152] S358: Maintain the current states of the negative electrode cooler 502 and the negative electrode heater 504.

[0153] Since in the process of the flow battery operation, the positive electrode electrolyte and the negative electrode electrolyte perform partition heat exchange inside the battery stack 101, the temperature management of the negative electrode electrolyte actually also completes the temperature management of the positive electrode electrolyte.

[0154] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A liquid flow battery system, characterized in that: It includes a battery stack unit, a positive electrode electrolyte transport unit, a negative electrode electrolyte transport unit, a positive electrode temperature management unit, a negative electrode temperature management unit and a control unit; The battery stack unit includes a battery stack, a power source and a load electrically connected to the battery stack respectively, a positive electrolyte inlet, a positive electrolyte outlet, a negative electrolyte inlet and a negative electrolyte outlet arranged on the battery stack, a positive electrolyte inlet pipe having one end connected to the positive electrolyte inlet, a positive electrolyte outlet pipe having one end connected to the positive electrolyte outlet, a negative electrolyte inlet pipe having one end connected to the negative electrolyte inlet, a negative electrolyte outlet pipe having one end connected to the negative electrolyte outlet, a first valve arranged on the positive electrolyte inlet pipe and a positive electrolyte outlet pipe having one end connected to the negative electrolyte inlet. A front-pole temperature sensor, a post-pole temperature sensor provided on the positive electrode electrolyte outlet pipe, a second valve and a front-pole temperature sensor provided on the negative electrode electrolyte inlet pipe, a post-pole temperature sensor provided on the negative electrode electrolyte outlet pipe, a positive electrode electrolyte bypass whose two ends are respectively connected to the positive electrode electrolyte inlet pipe and the positive electrode electrolyte outlet pipe, a negative electrode electrolyte bypass whose two ends are respectively connected to the negative electrode electrolyte inlet pipe and the negative electrode electrolyte outlet pipe, a third valve provided on the positive electrode electrolyte bypass, and a fourth valve provided on the negative electrode electrolyte bypass; The positive electrode electrolyte delivery unit comprises a positive electrode electrolyte storage tank, a positive electrode electrolyte delivery pump and a positive electrode temperature management bypass which are connected in sequence, and a fifth valve arranged on the positive electrode temperature management bypass, wherein the positive electrode temperature management bypass is connected to the positive electrode electrolyte inlet pipe; the positive electrode electrolyte storage tank is connected to the positive electrode electrolyte delivery pump through its outlet, and the positive electrode electrolyte storage tank is connected to the positive electrode electrolyte outlet pipe through its inlet; The negative electrode electrolyte delivery unit comprises a negative electrode electrolyte storage tank, a negative electrode electrolyte delivery pump and a negative electrode temperature management bypass which are connected in sequence, and a sixth valve arranged on the negative electrode temperature management bypass, wherein the negative electrode temperature management bypass is connected to the negative electrode electrolyte inlet pipe; the negative electrode electrolyte storage tank is connected to the negative electrode electrolyte delivery pump through its outlet, and the negative electrode electrolyte storage tank is connected to the negative electrode electrolyte outlet pipe through its inlet; The positive electrode temperature management unit includes a positive electrode heat exchanger, a positive electrode cooler, a positive electrode auxiliary circulation pump and a positive electrode heater. The positive electrode heat exchanger includes a positive electrode electrolyte flow branch and a positive electrode heat exchange medium flow branch. The positive electrode electrolyte flow branch is connected in parallel with the positive electrode temperature management bypass. A seventh valve is provided on the positive electrode electrolyte flow branch. The positive electrode heat exchange medium flow branch is connected to the positive electrode cooler, the positive electrode auxiliary circulation pump and the positive electrode heater in sequence. The negative electrode temperature management unit includes a negative electrode heat exchanger, a negative electrode cooler, a negative electrode auxiliary circulation pump and a negative electrode heater. The negative electrode heat exchanger includes a negative electrode electrolyte flow branch and a negative electrode heat exchange medium flow branch. The negative electrode electrolyte flow branch is connected in parallel with the negative electrode temperature management bypass. An eighth valve is provided on the negative electrode electrolyte flow branch. The negative electrode heat exchange medium flow branch is connected to the negative electrode cooler, the negative electrode auxiliary circulation pump and the negative electrode heater in sequence. The control unit is used to receive sensor signals from the positive electrode stack front temperature sensor, the positive electrode stack rear temperature sensor, the negative electrode stack front temperature sensor, and the negative electrode stack rear temperature sensor, respectively, and to control the on / off and opening of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the eighth valve, respectively; and is also used to control the output power of the positive electrode electrolyte delivery pump, the negative electrode electrolyte delivery pump, the positive electrode auxiliary circulation pump, and the negative electrode auxiliary circulation pump, respectively.

2. The liquid flow battery system according to claim 1, characterized in that: The positive electrode temperature management unit further includes a positive electrode auxiliary liquid storage tank connected to the positive electrode heat exchange medium flow branch; the negative electrode temperature management unit further includes a negative electrode auxiliary liquid storage tank connected to the negative electrode heat exchange medium flow branch.

3. The liquid flow battery system according to claim 1, characterized in that: The positive cooler includes a positive coolant flow branch and a ninth valve arranged on the positive coolant flow branch, and the control unit is also used to control the on-off and opening of the ninth valve; the negative cooler includes a negative coolant flow branch and a tenth valve arranged on the negative coolant flow branch, and the control unit is also used to control the on-off and opening of the tenth valve.

4. A method for preheating positive electrolyte of a liquid flow battery system before operation, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: Receive a positive electrode electrolyte preheating instruction, determine that the power supply and the load are in an off-load state, open the third valve and the seventh valve, close the first valve and the fifth valve, adjust the speed of the positive electrode electrolyte delivery pump to a first set value, adjust the speed of the positive electrode auxiliary circulation pump to a second set value, detect the current value of the positive electrode inlet temperature through the positive electrode stack front temperature sensor, and set the temperature required to be reached for positive electrode electrolyte preheating as the target value: The first step is to determine whether the current value of the positive electrode stacking temperature is less than its target value. If so, the heating power of the positive electrode heater is controlled to be interlocked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to determine whether the current value of the positive electrode stack temperature is greater than or equal to its target value. If so, the positive electrode electrolyte preheating is completed. If not, return to the first step for determination.

5. A method for preheating negative electrode electrolyte before operation of a liquid flow battery system, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: Receive a negative electrode electrolyte preheating instruction, determine that the power supply and the load are in an off-load state, open the fourth valve and the eighth valve, close the second valve and the sixth valve, adjust the speed of the negative electrode electrolyte delivery pump to a third set value, adjust the speed of the negative electrode auxiliary circulation pump to a fourth set value, detect the current value of the negative electrode inlet temperature through the negative electrode stack front temperature sensor, and set the temperature required to be reached for negative electrode electrolyte preheating as the target value: The first step is to determine whether the current value of the negative electrode stack temperature is less than its target value. If so, the heating power of the negative electrode heater is controlled to be interlocked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to determine whether the current value of the negative electrode stack temperature is greater than or equal to its target value. If so, the negative electrode electrolyte preheating is completed. If not, return to the first step for determination.

6. A method for cooling positive electrolyte of a liquid flow battery system after shutdown, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: Receive a positive electrode electrolyte cooling instruction, determine that the power supply and the load are in an off-load state, open the third valve and the seventh valve, close the first valve and the fifth valve, adjust the speed of the positive electrode electrolyte delivery pump to the fifth set value, adjust the speed of the positive electrode auxiliary circulation pump to the sixth set value, detect the current value of the positive electrode inlet temperature through the positive electrode stack front temperature sensor, and set the temperature that needs to be reached for the positive electrode electrolyte cooling as the target value: The first step is to determine whether the current value of the positive electrode stack temperature is greater than its target value. If so, the cooling power of the positive electrode cooler is controlled to be linked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to determine whether the current value of the positive electrode stack temperature is less than or equal to its target value. If so, the positive electrode electrolyte cooling is completed. If not, return to the first step for determination.

7. A method for cooling negative electrolyte of a liquid flow battery system after shutdown, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: Receive a negative electrode electrolyte cooling instruction, determine that the power supply and the load are in an off-load state, open the fourth valve and the eighth valve, close the second valve and the sixth valve, adjust the speed of the negative electrode electrolyte delivery pump to the seventh set value, adjust the speed of the negative electrode auxiliary circulation pump to the eighth set value, detect the current value of the negative electrode inlet temperature through the negative electrode stack front temperature sensor, and set the temperature that needs to be reached for the negative electrode electrolyte cooling as the target value: The first step is to determine whether the current value of the negative electrode stack temperature is greater than its target value. If so, the cooling power of the negative electrode cooler is controlled to be linked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to determine whether the current value of the negative electrode stack temperature is less than or equal to its target value. If so, the cooling of the negative electrode electrolyte is completed. If not, return to the first step for determination.

8. A temperature management method for a liquid flow battery system in operation, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: The voltage parameters and current parameters of the battery stack, as well as the flow parameters and temperature parameters of the positive electrolyte are collected, and the protection upper limit values ​​of the parameters are set. The flow target value of the positive electrolyte is set according to the proposed loading current of the battery stack, the flow rate of the positive electrolyte is interlocked with the rotation speed of the positive electrolyte delivery pump, PID control is implemented, and it is determined whether temperature control is required: If not, the seventh valve is closed, the fifth valve is opened, and the current value of the temperature before the positive electrode stack and the current value of the temperature after the positive electrode stack are respectively detected by the temperature sensor before the positive electrode stack and the temperature sensor after the positive electrode stack, and it is determined whether at least one of the two current values ​​is higher than the corresponding temperature protection upper limit value: if so, the shutdown process is entered; if not, the process returns to the previous step to continue the detection; If yes, close the fifth valve, open the seventh valve, and detect the current value of the temperature after the positive electrode stack through the positive electrode stack temperature sensor, and set the target value of the temperature after the positive electrode stack: The first step is to determine whether the current value of the temperature behind the positive electrode stack is greater than its target value. If so, the cooling power of the positive electrode cooler is controlled to be linked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to determine whether the current value of the temperature behind the positive electrode stack is less than its target value. If so, the heating power of the positive electrode heater is controlled to be interlocked with the current value, PID control is implemented, and then the third step is entered. If not, the third step is entered directly. The third step is to determine whether the current value of the temperature behind the positive electrode stack is equal to its target value. If so, the current state of the positive electrode cooler and the positive electrode heater is maintained. If not, return to the first step for determination.

9. A temperature management method for a liquid flow battery system in operation, implemented by the liquid flow battery system according to any one of claims 1 to 3, characterized in that: include: The voltage parameters and current parameters of the battery stack, as well as the flow parameters and temperature parameters of the negative electrode electrolyte are collected, and the protection upper limit values ​​of the parameters are set. The flow target value of the negative electrode electrolyte is set according to the proposed loading current of the battery stack, the flow rate of the negative electrode electrolyte is linked to the speed of the negative electrode electrolyte delivery pump, PID control is implemented, and it is determined whether temperature control is required: If not, the eighth valve is closed, the sixth valve is opened, and the current value of the temperature before the negative electrode stack and the current value of the temperature after the negative electrode stack are respectively detected by the temperature sensor before the negative electrode stack and the temperature sensor after the negative electrode stack, and it is determined whether at least one of the two current values ​​is higher than the corresponding temperature protection upper limit value: if so, the shutdown process is entered; if not, the process returns to the previous step to continue the detection; If yes, close the sixth valve, open the eighth valve, and detect the current value of the negative electrode stack temperature through the negative electrode stack temperature sensor to set the target value of the negative electrode stack temperature: The first step is to determine whether the current value of the temperature after the negative electrode stack is greater than its target value. If so, the cooling power of the negative electrode cooler is controlled to be linked with the current value, PID control is implemented, and then the second step is entered. If not, the second step is directly entered; The second step is to judge whether the current value of the temperature after the negative electrode stack is less than its target value. If so, the heating power of the negative electrode heater is controlled to be linked with the current value, PID control is implemented, and then the third step is entered. If not, the third step is directly entered; The third step is to determine whether the current value of the temperature after the negative electrode stack is equal to its target value. If so, the current state of the negative electrode cooler and the negative electrode heater is maintained. If not, return to the first step for determination.

Images