Study On Power-type Flow Electrochemical Energy Storage System

With the development of science and technology, the problem of energy resources and environment is getting sterner day by day. It is an urgent demand to make use of the energy which is clean and efficient. As a new energy storage type, the flow energy storage system was investigated extensively because its advantages such as long life, pollution-free, adjustable capacity. It will be a kind of green energy source in this century. The flow system, however, was used mainly for a large-scale energy storage. In this thesis, by changing the structure of electrode and flowing through the electrode of electrolytes, a novel battery based on the reaction of thin liquid layer can discharge with higher power and longer time, and that's what called power-type flow electrochemical energy storage system. The main results studied on the system were listed as follows:1. Flow electrochemical energy storage system was designed and demonstrated. And the condition of optimization was confirmed through the study on the influences of the thickness of electrode, the concentration of electrolyte and the velocity of flow. The cycle performance of batteries was tested respectively under different kinds of cationic membrane and anion exchange membrane. This paper tries to analyse the cause of bad cycle life and the change of the valency state analysis of vanadium ions in the process of self discharge performance.2. Study on the unit and system integration of flow electrochemical energy storage system. The stacks of power-type flow electrochemical energy storage system, the systematical integrated method, and the choice of the power-trains were discussed detailed.3. By the means of filter press, the stacks were prepared by using expanded graphite plates as current collector and as bipolar plates. The electrochemical performance of the stacks composed of 3 cells and 5 cells with active area of 12 cm~2 and 80 cm~2 separately was studied. The results show that the stack possessed the good electrochemical performance and homogeneity.