A method for online capacity recovery of all-vanadium redox flow battery

Abstract

The invention discloses a method for restoring the online capacity of an all-vanadium redox flow battery, comprising the following steps: S1: when the capacity of the all-vanadium redox flow battery decays and there is a demand for capacity restoration, measure V + and V ‑ , valence state x, total concentration of vanadium ions M + and M ‑ ; S2: the positive electrode electrolyte in the positive electrode storage tank is divided into two parts, V + 1 and V + 2 , and set the volume to V + 2 The positive electrode electrolyte of the electric stack passes through the electric stack and the pipeline and uses a pump to flow into the capacity recovery liquid storage tank; S3: the electric stack is charged, and the positive electrode of the electric stack has an oxidation reaction and side reactions, and the negative electrode of the electric stack A reduction reaction occurs; S4: monitoring M + 1 and M + 2 , when y is reached, stop charging; S5: Mix the electrolyte in the capacity recovery liquid storage tank with the positive electrode electrolyte in the positive electrode liquid storage tank to complete the online capacity recovery of the all-vanadium redox flow battery. The invention can reduce the valence state of vanadium ions in the positive electrode electrolyte, thereby realizing the balance of the valence state of the positive and negative electrode electrolytes, realizing capacity recovery, and avoiding the influence of adding a reducing agent.

Description

technical field [0001] The invention relates to the technical field of an all-vanadium redox flow battery, in particular to an online capacity recovery method of an all-vanadium redox flow battery. Background technique [0002] The electrolyte is the energy storage part of the all-vanadium redox flow battery, which has the characteristics of non-combustibility and non-explosion, and has high safety. The active substances in the positive and negative electrolytes are both vanadium ions, which can avoid cross-contamination of redox flow batteries similar to other positive and negative active substances. Therefore, the all-vanadium flow battery has a long life and low cost of electricity. At the same time, the electrolyte can be completely reused. [0003] Due to the ion-selective permeability of the ion-exchange membrane, during the charge-discharge cycle of the all-vanadium redox flow battery, the vanadium ions in the positive and negative electrolytes have a certain permeab...

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Problems solved by technology

[0004] The purpose of the present invention is to provide an online capacity recovery method for an all-vanadium redox flow battery, which solves the valence imbalance of the positive and negative electrolytes caused by the migration of vanadium ions, the side reaction of hydrogen evolution, and the possible oxidation of divalent vanadium by air in the prior art. The problem

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