Liquid level balancing system

Abstract

The invention discloses a liquid level balancing system, applicable to a vanadium redox flow battery which comprises a battery stack, a positive electrolyte tank used for storing positive electrolyte and connected with the battery stack to form a first circulation loop, and a negative electrolyte tank used for storing negative electrolyte and connected with the battery stack to form a second circulation loop. The liquid level balancing system comprises a detection unit connected with the positive electrolyte tank and the negative electrolyte tank respectively, an adjusting unit connected with the first circulation loop and the second circulation loop respectively, and a management unit, connected with the detection unit and the adjusting unit respectively. The liquid level balancing system has the advantages that the existing floe battery system is improved aiming at main reasons causing the variation of liquid level difference, the liquid level balancing state of the positive and negative electrolyte tanks can be rapidly recovered, and the structure is simple, the cost is low, the apparatus is convenient to maintain and the degree of automation is high.

Description

technical field [0001] The invention relates to the field of liquid flow batteries, in particular to a liquid level balance system applied to all-vanadium redox flow batteries. Background technique [0002] The all-vanadium redox flow battery is considered to be one of the most suitable electrochemical energy storage devices for large-scale energy storage. It uses vanadium ions in different valence states as the positive and negative electrolytes, and drives the positive and negative electrolytes in the stack through a pump. operate independently of each other. However, during the independent operation of the positive and negative electrolytes, because the medium that blocks the positive and negative electrolytes, that is, the DuPont diaphragm, has no barrier effect on water molecules, the pressure changes on both sides of the diaphragm inside the stack will change during the operation of the battery. After the battery has been running for a period of time, the amount of el...

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Problems solved by technology

[0003] At present, some scholars have proposed to integrate the positive and negative electrolyte tanks, set a separator in the middle, and set a certain size of through hole at the position of the separator, through the through hole to ensure the liquid level and temperature of the positive and negative electrolyte are even. Keep balance, but this method of setting through holes will cause the positive and negative electrolytes to mix and cause the battery to self-discharge, seriously affecting the battery efficiency

Some researchers have proposed to solve the liquid level fluctuation of the liquid storage tank caused by water migration by establishing an air pressure balance between the positive and negative electrolyte tanks, but this method only considers the influence of external gas on the liquid pressure, and does not consider the pressure caused by the pressure. The main factor of the change is the influence of different pump power

Therefore, the devices currently used to solve the problem of water migration all have problems such as high cost, complicated operation, and difficult maintenance.

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