Energy storage equipment voltage balance method and system

Abstract

The invention discloses an energy storage equipment voltage balance method. The method comprises the steps that when the voltage difference of a single power source in a series-connection (power source) energy storage equipment unit reaches a set value, after the high-voltage single power source and other one or more single power sources are in series connection, a flying capacitor is charged, the voltages of the high-voltage single power source is lowered, then the low-voltage single power source is charged by a plurality of flying capacitors which are in series connection, the voltage of the low-voltage single power source is improved, and so repeatedly, voltage balance of energy storage equipment is achieved. The invention further discloses a voltage balance system using above method. According to the energy storage equipment voltage balance method and system, supercapacitors which are in series connection are used as flying elements, the problem that traditional voltage differences are too small is solved, the requirement for large-power charging and discharging is met, sufficient capacity can further be provided, and the energy transferring efficiency is improved. According to the energy storage equipment voltage balance method and system, circuits are simple, balance currents can be adjusted and balanced according to the number of the flying supercapacitors needing to be in combined series connection, and the flexibility of control is improved.

Description

technical field [0001] The invention relates to the technical field of power management systems of energy storage devices, in particular to a method and system for voltage balance in the management system of energy storage devices. Background technique [0002] With the rapid development of new energy industries such as new energy vehicles and new energy power generation, new energy storage has become a key technology. Products used for new energy storage mainly include lead-acid batteries, lithium-ion batteries, and supercapacitors. The voltage of these products is very low, generally less than 5V. However, these new energy storage applications often have a voltage of hundreds or even thousands of V. Therefore, in practical applications, it is necessary to combine the monomers of energy storage products in series and parallel, and design the series and parallel structure according to the required voltage and capacity. For example, a 600V400AH bus power system requires bat...

AI Technical Summary

Problems solved by technology

The advantages of this method are: the circuit structure is simple and the cost is low; but the disadvantages are: the charging energy is completely consumed on the voltage regulator tube, the voltage regulator tube will be seriously heated, and the energy waste is serious; the breakdown voltage accuracy of the voltage regulator tube is low, and the dispersion poor performance, which reduces the reliability of the voltage balance circuit, and does not have the ability to balance the whole process in real time. Therefore, the first method is only suitable for occasions where the charging power is very small

Compared with the first two equalization methods, the third DC / DC bidirectional converter method has the advantages of low energy loss, fast voltage equalization speed, and voltage equalization for both charging and discharging states; but the disadvantage is: the required inductance There are many power devices such as switching tubes and switching tubes, the control is complicated and the cost is high

The advantages of this method are: low energy loss, fast voltage equalization speed, and voltage equalization can be performed on both charge and discharge states; but the disadvantage is that the capacity of the capacitor is limited compared with the energy storage unit, and the balance requires multiple switching of the switching network and the balance time Long, the system reliability and balance efficiency are difficult to meet the requirements, and it is difficult to select the switching device in the implementation. If the relay is used, the reliability of the relay itself is poor, and there will be sparks when the contact switch is switched. If the electronic switch is used, there will be defects in the electronic switch itself. The voltage drop causes the balance effect to deteriorate, that is, the voltage difference between the supercapacitor and the flying supercapacitor is too small, and the balance current will be very small

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