Lithium ion power battery pack balanced discharge management system

Abstract

The invention discloses a lithium ion power battery pack balanced discharge management system, which comprises an MCU central control unit, a voltage, current and temperature monitoring module for monitoring battery information, a balanced discharge module, a battery radiating module, a battery module and a high voltage power bus. The voltage, current and temperature monitoring module feeds monitored information back to the MCU central control unit; and after the monitored information is analyzed by the MCU central control unit, the operation of the battery radiating module and the balanced discharge module is controlled, and the battery module discharges through the high voltage power bus in a balanced way, wherein the balanced discharge module consists of a plurality of resistances and a plurality of analogue switches; each battery in the battery module is connected with the resistances and the analog switches; the resistances are used for distributing the current of the batteries; and the analog switches are used for controlling the operation of the resistances. The lithium ion power battery pack balanced discharge management system has the advantages of accurate control of the balanced discharge, higher safety and support of heavy-current discharge.

Description

technical field [0001] The invention belongs to the technical field of battery management, and in particular relates to a lithium-ion power battery pack balanced discharge management system. Background technique [0002] Due to energy and environmental considerations, electric vehicles have achieved rapid development under the joint promotion of governments and automakers. Pure electric vehicles have become one of the important development directions of electric vehicles because they can truly achieve "zero emissions". As a green means of transportation, electric vehicles will bring great changes to human society in the 21st century. Lithium-ion batteries have become an ideal power source for pure electric vehicles due to their high energy density and high voltage platform. However, lithium-ion batteries are less resistant to abuse. The safety and long life of lithium-ion batteries, especially group lithium-ion batteries, have become an urgent problem to be solved in the ...

AI Technical Summary

Problems solved by technology

Among them, O2 is an early producer of hybrid ICs that can manage a large number of battery strings. At the beginning, it mainly used OZ890 as the main product. Later, it launched the OZ8920 with a maximum of 8 strings, and then made 16 strings through two cascaded connections. The circuit is more complicated, and the price is relatively high; TI is mainly based on the early notebook battery management chips. This series of chips mainly have different handling methods for power balance. The way of shunting, but its price is expensive and the circuit is relatively complicated; Intersil products are mainly based on 9208, 9216, 9217 and other chips, of which 9216 and 9217 can be used in pairs to form a battery management system with up to 12 strings, but 9208, 9216 and 9217 They are all passive devices and require an external MCU to control their work, so the development is relatively difficult and the system cost is relatively high; MAX products are mainly chips that can manage 10 strings of batteries, and their functions and operating modes Similar to O2 and TI, the price is comparable to TI's 10-series chips; Linear Technology products are mainly based on the analog front end of batteries, and can reach more than 10 strings at most, but their prices are quite expensive, and it is difficult for ordinary civilians to accept them.

[0006] (3) MCU (microcontroller or single-chip microcomputer) management method is adopted. The application of MCU in lithium battery management system is very suitable, and it is very convenient to realize real-time battery balance management according to the state of battery charging. At present, the main balance management method It is a two-way lossless equalization technology, that is, each battery is equipped with an equalization circuit, which requires two power MOSs, but its problem is that the control of the equalization management system becomes complicated, the reliability decreases, and the cost rises. Once one of the devices is damaged, The risk of short circuits is extremely high, and it is almost impossible to maintain. If a large equalization current is required, various problems will be more prominent

The traditional method of judging whether to perform balanced discharge by measuring the open circuit voltage of the battery cannot accurately reflect the state of charge of a single battery, and the battery often appears to be over-discharged.

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