System for detecting and proactively balanced charging lithium ion battery pack

Abstract

The invention relates to a lithium ion battery, in particular to a system for detecting and proactively balanced charging a lithium ion battery pack. The system comprises a series battery pack, a charging power supply, a battery voltage detection module, an energy overflow module, a master control module, a charging energy limiting control module, a switching module, a V-I conversion module, an I-V conversion module, an analog-to-digital converter, a controller, and a precision voltage reference device, wherein the series battery pack includes a plurality of batteries connected in series. Thesystem realizes online completely balance of the individual batteries in the battery pack, achieves coincidence of the same-capacity batteries with different charge and discharge curves, solves the inaccurate measurement caused by poor unit battery voltage detection accuracy in the battery pack and the disconnection of a series connection point detection line. By using a method for assessing the SOC of the overall battery pack by an individual battery coulometry and by integrating Kalman filter, the coulometry and the electromotive force method are combined to achieve the closed-loop evaluation of the SOC of the lithium ion battery, and the problem of inaccurate numerical value of the battery pack capacity evaluation is solved.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a detection and active balance charging system for a lithium ion battery pack. Background technique [0002] In recent years, with the rapid development of lithium-ion batteries, the continuous emergence and application of new materials, the maturity of process technology and the decline in cost, lithium-ion batteries with excellent performance can completely replace lead-acid batteries as a communication or power field. The foundation for demanding power solutions. [0003] The voltage and capacity of a single storage battery are limited, and in many cases it is necessary to form a battery pack connected in series. The voltage balance of the battery pack is an important issue related to the service life of the battery pack, the stability and safety of the system. Due to the aging degree of single batteries and the influence of temperature, the state of each single battery is inconsiste...

AI Technical Summary

Problems solved by technology

[0004] However, the existing battery pack has the following disadvantages: 1. It cannot be managed online; 2. It adopts periodic management and cannot manage in real time; 3. It cannot manage the discharge of the entire battery pack

In this scheme, the higher the voltage is, the larger the resistance divider ratio is, and at the same time, the resulting voltage error is also large.

Therefore, in the high-voltage system, the sampling A / D resolution is required to be very high, which greatly increases the cost of the product and the difficulty of product realization.

[0007] (2) Parallel capacitor mirroring method. In this method, the capacitor is first connected in parallel to the battery to be tested, and then disconnected. The system realizes the battery voltage test by testing the capacitor voltage. In this scheme, the capacitor is continuously charged and discharged. It is easy to cause quality problems, which will eventually affect the measurement accuracy. At the same time, if the capacitance is too large, it will easily cause the loop to be damaged due to overcurrent, while if the capacitance is too small, the measurement drift will be caused by the discharge of the loop.

[0008] The prior art mainly includes various systems of the above and other aspects, and there are various limitations in practical application

Images