A flexible parallel device suitable for energy storage batteries

Abstract

The invention is a flexible parallel device suitable for energy storage batteries. By adding independent capacitors to the battery strings and controlling the independent capacitors through isolated DC / DC converters, the voltage of the battery strings can be flexibly adjusted to realize an energy storage system. The flexible parallel connection of different battery strings can be applied to energy storage systems using new batteries and cascaded batteries, and supports the use of lithium-ion batteries of different brands or specifications in different strings working in parallel. Solve the simple and efficient series-parallel connection of battery strings in the energy storage system, while taking into account the use of cascade utilization batteries.

Description

technical field [0001] The patent of the present invention relates to the field of energy storage applications, especially to the field of energy storage applications using lithium ion batteries as energy storage elements. [0002] technical background [0003] With the continuous development of new energy sources, especially the rapid growth of intermittent and fluctuating new energy sources such as photovoltaics and wind power, the fluctuation of the power grid is very large. A power storage unit is needed to stabilize the power fluctuation of such power generation units. ; The current user-side load, especially the peak-to-valley difference of industrial and commercial loads, is very large. Adding power storage units can reduce the peak-to-valley difference of electricity load. Considering the national peak-valley electricity price, there is also a corresponding business model; With the continuous emphasis on energy storage and the continuous promotion of the policy level,...

AI Technical Summary

Problems solved by technology

[0004] Lithium-ion batteries are all in the form of single cells. Due to the limitation of battery cell capacity, large-capacity lithium-ion battery energy storage systems are the result of a large number of single cells connected in series and parallel. At present, the traditional form is that several single cells are connected in parallel. After that, they are connected in series to form a battery string, and multiple battery strings are connected in series and parallel to form a large-capacity energy storage system. However, the internal resistance of lithium-ion batteries is very small. It takes a lot of time and effort to connect the two battery strings from independent to parallel.

In addition, especially for batteries used in cascades, the difference between the battery cells in the same battery string is relatively large, and the difference between the battery strings is also very large, resulting in a large reduction in the capacity of the lithium battery energy storage system connected in parallel, and cannot play its due effect.

Images