Lithium battery pack short-circuit protection circuit

Abstract

The invention provides a lithium battery pack short-circuit protection circuit comprising a short-circuit protection current reference circuit which acquires reference current, a short-circuit current acquisition circuit which acquires short-circuit current, a current comparison circuit, an MCU circuit, a charging execution circuit and a discharge execution circuit. The current comparison circuit is a comparator. The short-circuit current acquisition circuit acquires real-time current from a lithium battery pack and transmits real-time current to the positive phase input end of the comparator. The short-circuit protection current reference circuit acquires reference current from the MCU and transmits reference current to the negative phase input end of the comparator. The output end of the comparator is connected with the high-priority external interruption input pin of the MCU. A short-circuit protection current size threshold and a short-circuit protection delay time threshold are arranged in the MCU. Short-circuit misoperation in electrification of a capacitive load can be effectively avoided, and a complex and tedious short-circuit protection execution unit is removed simultaneously so that materials are reduced and cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of circuit control, and relates to the design of an internal circuit of an electric tool, in particular to a short-circuit protection circuit for a lithium battery pack. Background technique [0002] In high-power applications such as post and telecommunications, energy storage, and electric vehicles, lithium batteries require a combination of multiple batteries in series and parallel to meet the needs of voltage and power. Due to the influence of external conditions such as differences in production process, aging of battery lines, and changes in load performance, the battery pack may be short-circuited. After the battery is short-circuited, it is easy to cause damage such as load burnout and battery emptying, causing great damage. If it is found that the battery short circuit is not remedied in time, it will cause fire and even casualties. It can be seen that it is very important to introduce short-circui...

AI Technical Summary

Problems solved by technology

The short-circuit protection delay time needs to be adjusted through hardware parameters, and different hardware parameters need to be set for different system protection times, resulting in complex production processes

Moreover, when the pure hardware short-circuit protection circuit works, it is easy to cause parasitic oscillation of the charging and discharging MOS tube, and the oscillation voltage can reach twice the voltage of the battery pack. At this time, the MOS tube needs to have a large DS working voltage, which will lead to an increase in the cost of the MOS tube.

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