All-vanadium redox flow battery electrolyte formula and process for inhibiting precipitation of easily precipitated element impurities in electrolyte

Abstract

The invention belongs to the field of inhibition of precipitation of easily precipitated elements in an electrolyte, and discloses an all-vanadium redox flow battery electrolyte formula and process for inhibiting precipitation of easily precipitated element impurities in the electrolyte. According to different precipitation characteristics and precipitation conditions of elements prone to precipitation, the highest limit value which can be borne by electrodes in a vanadium electrolyte and a battery is comprehensively considered, the elements prone to precipitation are controlled according to the concentration upper limit when a certain main group (or subgroup) exists at the same time or exists singly, and a concentration interval for long-time safe operation of the system is given. The content of the easily precipitated elements can be effectively controlled, the stability of the electrolyte is improved, the service life of equipment such as a battery resistor is prolonged, and the cost of the electrolyte is effectively reduced.

Description

technical field [0001] The invention belongs to the field of inhibiting the precipitation of easily precipitated elements in an electrolyte, and in particular relates to a formula and a process for an all-vanadium redox flow battery electrolyte for inhibiting the precipitation of easily precipitated elements and impurities in an electrolyte. Background technique [0002] In the existing all-vanadium redox flow battery electrolyte quality standards, the requirements for impurity metal ions in the electrolyte are single, that is, except for the main element vanadium (V), the content of other elements is kept in a very low range, but its quality There is a lack of understanding and restriction standards for easily precipitated elements in the standard. Some element ions have the characteristics of easy hydrolysis, low solubility, and co-ion precipitation. When they exist in the vanadium electrolyte, they will combine into insoluble substances, oxides or salts under certain cond...

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Problems solved by technology

At the same time, after the precipitation blocks the flow channel of the pipeline, the difference in the renewal speed of the positive and negative electrode solutions will lead to an imbalance in the charge of the negative electrode electrolyte, which will increase the self-discharge of the battery system and gradually reduce the discharge capacity.

[0003] At the same time, the control and detection methods of some elements are lacking. Once they enter the electrolyte, they are often difficult to get rid of, and their continuous accumulation characteristics make them have a great impact on the system capacity and efficiency. This is why the flow rate of many vanadium battery systems suddenly decreases. One of the main reasons for the rapid decrease in discharge capacity

From the perspective of practical application of these elements in the electrolyte, the upper limit of the allowable concentration has not yet been reported in relevant applications, and there is no qualitative and quantitative explanation; in addition, the existing all-vanadium electrolyte requires high purity of vanadium as a raw material (> 98%), resulting in high cost of electrolyte

[0004] However, over-limiting the content of these elements will directly lead to an increase in the production cost of the electrolyte and the procurement cost of raw material vanadium. 1mg / L or less, so that the raw material vanadium required for electrolyte production will have to use raw materials with a purity >98%, so that the raw material procurement cost will be about 15% higher than that of raw material vanadium with a purity of 97%.

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