Whether from the perspective of battery production capacity or project installation planning, flow batteries (Vanadium Battery) have entered the GW.

As the core power unit of the flow battery, the stack is rapidly moving toward high power and high efficiency to cater to the market's cost reduction and scale development trends.

The stack can be called the heart of the flow battery.

A complete flow battery energy storage system mainly consists of power unit (electric stack), energy unit (electrolyte and electrolyte storage tank), electrolyte delivery unit (pipelines, pump valves, sensors, etc.), battery management The system is composed of other parts. The power unit determines the system power, and the energy unit determines the system energy storage capacity. The two are independent of each other.

The power of a flow battery only depends on the size of the stack, and the capacity only depends on the electrolyte storage and concentration, which means it can be designed flexibly. When you need to increase the storage capacity, you only need to increase the volume of the electrolyte storage tank or increase the concentration of the electrolyte; if you want to increase the power, you only need to increase the power of the stack or increase the number of stacks. Adaptability Very strong.

Taking vanadium batteries as an example, the stack is the main part of the vanadium battery and is also the place where electrochemical reactions occur. The main structure includes proton exchange membranes, electrodes, bipolar plates, copper current collector plates, liquid flow frames, end plates and connectors. Etc.

According to data from the International Renewable Energy Organization (IRENA), the cost of vanadium flow batteries is mainly divided into three parts: stack, electrolyte and peripheral equipment costs. The stack and electrolyte are the main costs, accounting for about 75% in total, and the cost of other components accounts for about 25%; among them, the cost of vanadium electrolyte accounts for about 40%, and the cost of the stack accounts for about 35%; in the stack, the separator It is the core again, and the cost accounts for about 40% of the stack.

It can be seen that to reduce the cost of vanadium batteries, we must start from the two "big ends" of the stack and electrolyte.

Among them, an effective way to reduce the cost of the stack is to improve the power and energy efficiency of the stack.

According to current public information, the maximum power of domestic vanadium battery stacks is already moving towards the 128kW level. The increase in single stack power can effectively reduce system cost and system volume.

In terms of energy efficiency, Zheng Xiaohao, general manager of Liquid Flow Energy Storage Technology Co., Ltd., said that currently, the energy efficiency of the all-vanadium flow battery stack of Liquid Flow Energy Storage Technology is around 78%; while the iron-based flow battery representative company Juan Technology CEO Meng Jintao said that the company's all-iron redox flow battery stack efficiency and system efficiency are both above 80%.