Single-battery-based on-line estimation method for SOC of series battery pack

Abstract

The invention discloses a single-battery-based on-line estimation method for a state of charge (SOC) of a series battery pack. The method comprises: a central controller sends a time reference and a soft synchronization sampling time interface to all local controllers; the central controller caries out current sampling and records a time stamp; all local controllers carry out voltage and temperature sampling on single batteries and record time stamps; all local controllers carry out soft time stamp synchronization on voltages, currents, and temperatures of all single batteries; all local controllers carry out recursion and on-line identification of parameters of all single batteries; all local controllers carry out adaptive estimation on SOCs of all single batteries; and the central controller calculates an SOC of the series battery pack. With the method, on-line estimation of the SOCs of all single batteries in the series battery pack as well as on-line estimation of the SOC of the series battery pack based on the on-line estimation of the SOCs of all single batteries can be realized. The method has characteristics of high SOC estimation precision and good adaption to different application environment conditions, the operation condition, and the lift cycle of the series battery pack.

Description

technical field [0001] The invention relates to battery management system technology, in particular to an on-line estimation method for SOC of a battery pack connected in series based on a single battery. Background technique [0002] The state of charge SOC is used to represent the remaining power of the battery. It is an important parameter for evaluating the remaining capacity of the battery, using the battery reasonably and fully, and avoiding the abuse of the battery. For electric vehicles, the reliable estimation of high-precision SOC is to solve the mileage anxiety of electric vehicles important basis for the problem. In order to meet the high power and large energy storage requirements of batteries such as electric vehicles, it is necessary to use single cells in series. [0003] There are many factors that affect the accuracy of SOC estimation, including environmental conditions, operating conditions, and electrochemical effects inside the battery, etc., which cann...

AI Technical Summary

Problems solved by technology

However, due to the cost and the complexity of the battery management system, the existing SOC estimation methods for series-connected battery packs cannot realize the online estimation of the SOC of the single cells in the series-connected battery pack, so that the estimated series-connected battery pack There is a large error between the SOC of the series battery pack and the actual SOC of the series battery pack, which leads to the failure to fully utilize the actual charge and discharge capacity of the series battery pack, resulting in a waste of battery capacity; or there is a desire to make full use of the battery pack. The risk of battery misuse

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