Power-taking circuit of lithium battery management system for preventing overdischarge in UPS

Abstract

The invention provides a power-taking circuit of a lithium battery management system for preventing overdischarge in UPS. The battery management system is connected with positive and negative ends of a lithium battery group by virtue of a DC / DC power supply, the lithium battery group provides electric energy to the UPS, a discharge relay is connected between the negative electrode of the lithium battery group and the UPS, the discharge relay is connected with a charge relay in parallel, and the battery management system respectively controls the lithium battery group to discharge and charge by virtue of the discharge relay and the charge relay; a self-restoring normally open switch is additionally arranged between the DC / DC power supply and the negative electrode of the lithium battery group and the negative electrode of the DC / DC power supply is communicated with the negative electrode of the UPS. The circuit provided by the invention has the advantages and positive effects that overdischarge damage caused by discharge of the DC / DC power supply to the lithium batteries again when the battery group is emptied is effectively avoided, and moreover, the circuit can be independently started without the dependence on alternating electric supply; the circuit is simple to implement and can reliably protect the lithium battery, so that the cost is less.

Description

technical field [0001] The invention belongs to the technical field of new energy sources, and in particular relates to a power-taking circuit for a lithium battery management system used in an UPS to prevent over-discharge. Background technique [0002] As a new type of energy storage medium, lithium batteries are more and more widely used in various fields because they are lighter in weight, smaller in size and more environmentally friendly than lead-acid batteries. In order to prevent the lithium battery pack from being over-discharged or overcharged, a battery management system must be equipped to control the charging and discharging of the lithium battery pack through a charging relay and a discharging relay. For example, in the UPS power supply, when the mains power exists, the UPS will rectify the mains power into direct current and charge the lithium battery pack. When the management system judges that the battery pack is fully charged, it will disconnect the chargin...

AI Technical Summary

Problems solved by technology

This method can prevent the battery pack from completely disconnecting the load when it is empty, and there will be no current loss that will cause the lithium battery to be over-discharged. However, this method must rely on AC mains for the system to start normally. Normally let the battery management system get DC 12V power to make the relay work

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