Charging current limiting device and method for battery of energy storage system

Abstract

The invention relates to a charging current limiting device for batteries of an energy storage system. The charging current limiting device comprises a control unit, a charging current limiting circuit, a monitoring unit and a data processing unit, wherein the charging current limiting circuit comprises a first field effect transistor, an inductor, a capacitor, a freewheeling diode and a sampling resistor; a source electrode of the first field effect transistor is connected with a negative electrode of a power supply, a drain electrode of the first field effect transistor is connected with a first end of the inductor, a second end of the inductor is connected with one end of the sampling resistor, and the other end of the sampling resistor is connected with a negative electrode side of a battery string; and the capacitor is connected with the freewheeling diode in parallel, a first end common coupling point after the parallel connection of the capacitor and the freewheeling diode is connected between the drain electrode of the first field effect transistor and the inductor, and a second end common coupling point is connected between a positive electrode of the power supply and a positive electrode side of the battery string. The charging current limiting device is used for performing charging current limiting control on the batteries of the energy storage system and providing the batteries with constant current for charging, thereby improving performance of the batteries.

Description

technical field [0001] The invention relates to an energy storage system, in particular to a device and method for limiting charging current of a battery of the energy storage system. Background technique [0002] Energy storage technology is mainly divided into electricity storage and heat storage . At present, energy storage methods are mainly divided into three categories: mechanical energy storage, electromagnetic energy storage, and electrochemical energy storage. The energy storage system in this application refers to a power supply system composed of batteries and bidirectional converters that stores and releases electric energy. The battery part of the energy storage system is called the battery system, and the battery system is divided into a cell array and a battery management system. The battery system of a large-scale energy storage system (1MWh) is composed of a large number of batteries connected in series in a certain way. Due to the consistency of lithium...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that in the prior art, due to the inconsistency of the internal resistance of the battery cells, after the energy storage system has been running for a period of time, the internal resistance of the parallel battery strings (including the battery strings with the same distribution resistance) is inconsistent, and the As time goes by, it will become more and more serious, seriously affecting the technical problem of the service life of the battery system. The present invention provides a technical solution to solve this technical problem, that is, adding a charging current limiting control circuit at the confluence of battery series and parallel connections. and control its current

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