Flow battery stack and method for improving voltage abnormity at flow battery end

Abstract

The invention relates to a flow battery stack and a method for improving voltage abnormity at a flow battery end, and belongs to the field of flow batteries. The flow battery stack comprises an end plate, a current-collecting plate and a bipolar plate from an outermost side to the inside, wherein a conducting layer is arranged between the current-collecting plate and the bipolar plate; and the conducting layer is made of a conducting material of which the electrical resistivity is less than 0.5omega.cm. The conducting layer is arranged between the bipolar plate and the current-collecting plate, so that the voltage abnormity at a stack end is improved effectively; the voltage uniformity among single batteries in the stack is ensured; the stack performance is enhanced; and meanwhile, the service life of the stack is greatly prolonged.

Description

technical field [0001] The invention relates to a liquid flow battery electric stack and a method for improving the abnormal voltage of a liquid flow battery terminal, belonging to the field of liquid flow batteries. Background technique [0002] The world-wide energy shortage and the aggravated deterioration of the environment have prompted the calls of countries all over the world to develop and utilize renewable energy. However, no matter solar or wind energy, there is instability in energy supply, and an energy storage system with excellent performance is required to match it. Flow batteries have the advantages of good safety, high reliability, flexible design, fast response, and long life, and are ideal large-scale energy storage devices. [0003] The stack of the flow battery is mainly composed of multiple single cells superimposed and fixed together in the form of a filter press. The outermost sides are respectively the end plate for fastening the stack and the curre...

AI Technical Summary

Problems solved by technology

In the existing stack structure, the bipolar plate at the outermost terminal cell (the single cell at both ends of the stack in the flow battery) is often in direct contact with the current collecting plate, because the bipolar plate and the current collecting plate The material, composition, and surface state of the adjacent surfaces of the two are quite different. Although the stack is assembled by external pressure to make the two closely contact together, there is still a large contact resistance between the two, resulting in terminal battery The internal resistance of the battery increases significantly, which in turn increases the internal resistance of the stack, affecting the performance and service life of the stack

What's more deadly is that due to the contact resistance between the bipolar plate and the collector plate with the terminal battery attached, the voltage of the terminal battery (the voltage of the terminal battery) is often significantly higher or lower than the voltage of other single cells, serious The situation will reach a deviation of hundreds of millivolts from the average voltage of the stack, which seriously affects the overall voltage uniformity of the stack

When the stack is operated under this condition for a long time, the terminal batteries of the stack are under high voltage or high current for a long time during charging and discharging. Over time, the terminal batteries on both sides of the stack are easily damaged, which reduces the power of the stack. The service life and charging and discharging efficiency also greatly increase the workload and cost of later maintenance

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