Equalizing charge management system of lithium ion power battery pack

Abstract

The invention discloses an equalizing charge management system of a lithium ion power battery pack. The system comprises an external voltage alternating current converter, an MCU central processing unit, a voltage, current and temperature monitoring module used for monitoring battery information, a plurality of equalizing charge modules, a battery heat radiating module and a plurality of battery modules, wherein the voltage, current and temperature monitoring module feeds the monitored information back to the MCU; the MCU analyzes the information and sends a command to the equalizing charge modules and the battery heat radiating module to control charge equalization of every battery in the battery modules; each battery module is connected with one equalizing charge module; each equalizing charge module consists of a control switch, a spoiler and a transformer; the control switch is connected with the spoiler and the transformer respectively; the control switch is connected with the external voltage alternating current converter; the spoiler is connected in parallel with the battery modules; and the transformer is connected in parallel with the battery modules. The equalizing charge management system realizes high-current equalizing charge in a mode of early-constant current and later-disturbed flow.

Description

technical field [0001] The invention belongs to the technical field of battery management, and in particular relates to a lithium-ion power battery group balanced charging management system with functions of balanced charging, fast charging, overvoltage, overcurrent and overtemperature protection. Background technique [0002] Due to energy and environmental considerations, electric vehicles have achieved rapid development under the joint promotion of governments and automobile manufacturers. Pure electric vehicles have become one of the important development directions of electric vehicles because they can truly realize "zero emission". As a green vehicle, 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 excellent performance such as high energy density and high voltage platform. However, lithium-ion batteries are less resistant to abuse. The sa...

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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 mode of constant current charging in the early stage and constant voltage charging in the later stage not only cannot charge the battery in a balanced manner, but also the fastest charging time is 2-3 hours

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