High and low temperature shutdown self-protection method and device for flow battery system

Abstract

The invention discloses a method and a device for realizing self protection on high-low temperature halt of a flow battery system. The method comprises the following steps: judging whether the flow battery system receives a halt command or is in a halt state, and monitoring environment temperature T if the flow battery system receives a halt command or is in a halt state; determining the normal range of SOC (state of charge) of an electrolyte in a positive electrode storage or a negative electrode storage tank according to the environment temperature T; and judging whether the SOC of the electrolyte in the positive electrode storage or the negative electrode storage tank is within respective corresponding normal range, and reducing the SOC of the electrolyte in the positive electrode storage or the SOC of the electrolyte in the negative electrode storage tank if the SOC of the electrolyte in the positive electrode storage or the negative electrode storage tank is not within the respective corresponding normal range. The method and the device are capable of improving the electrolyte stability of the flow battery system under a high-low temperature halt condition, improving the self protection capability of the flow battery system, reducing the capacitance loss under a high-low temperature condition, prolonging the service life and improving the performance of a flow battery.

Description

technical field [0001] The invention relates to a high and low temperature shutdown self-protection method and device for a liquid flow battery system. Background technique [0002] Liquid flow battery has the advantages of flexible design (power and capacity can be independently designed), long service life, good charge and discharge performance, free site selection, high energy efficiency, safety and environmental protection, low maintenance cost, and easy realization of large-scale storage. Many advantages not available. In practical applications, liquid flow batteries can be widely used in renewable energy power generation systems such as wind energy and solar energy as energy storage systems, so that the generated electricity can be output continuously and stably; The power in low valleys is stored and output during peak power consumption to balance power supply and demand; in addition, it can also be used as an emergency power system and backup power station, etc., wh...

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Problems solved by technology

[0003] In the actual application process of the flow battery system, there will be a shutdown situation according to actual needs, and sometimes the shutdown time is long; the SOC of the flow battery system when the shutdown situation occurs is often random, and the SOC between 0 and 100% It is all possible. In order to avoid damage to the stack due to internal self-discharge when the flow battery system is powered down, the electrolyte in the stack is discharged by means of an external resistor in the prior art to achieve protection. The role of the flow battery system, and the electrolyte in the positive and negative electrolyte storage tanks has no self-discharge channel due to the stop of the circulation pump, so it cannot be discharged after shutdown; but when the flow battery system is in a low temperature environment after shutdown, such as During the long-term storage in winter, due to the poor tolerance of divalent vanadium ions, divalent vanadium ions in the electrolyte are prone to crystallization and precipitation, and the precipitated crystals are started and charged and discharged in the flow battery system. will partially enter the stack and damage the ion-conducting membrane material; similarly, when the flow battery system after shutdown is in a high-temperature environment, since the pentavalent vanadium ions cannot withstand higher temperatures, when the ambient temperature is higher than a certain temperature After that, the pentavalent vanadium ions will form precipitates, which will significantly reduce the performance and life of the flow battery system

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