A Method for Battery Pack State of Health Estimation Using Large Database Analysis

Abstract

The invention discloses a method for utilizing big database analysis to carry out battery pack health state estimation. The method comprises the steps that: in a vehicle operation process, a battery management system of an electric automobile sends a battery state quantity to a vehicle operation database server by means of remote communication, and a vehicle-mounted system synchronously sends vehicle operation information to the vehicle operation database server; the vehicle operation database server collects full life-cycle data, a calibration SOH mapping table is obtained by means of big data analysis, and later on, according to the received battery state quantity and the vehicle operation information, the vehicle operation database server carries out SOH estimation based on the SOH mapping table and sends an SOH estimated value back to the electric automobile. The method provided by the invention is independent of original theoretical data of a single battery, and the errors of SOH estimation caused by battery grouping and condition environments are eliminated; in addition, big data analysis is utilized, so that the SOH estimated value of the electric automobile is more precise.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, and more specifically relates to a method for estimating the state of health of a battery pack by analyzing a large database. Background technique [0002] For electric vehicles, the power battery is a very common energy storage component, and its performance plays a decisive role in the performance of the vehicle. In the power battery, lithium-ion batteries are used as an important energy storage medium, and have been widely used in the field of new energy. Wide range of applications. [0003] Since the battery will inevitably age or deteriorate after long-term use, it is necessary to estimate the state of health (SOH) of the battery, also known as the life state, and some are also called aging, deterioration degree or settled battery. The standard definition of battery SOH is the ratio of the capacity released by the power battery from the full state to the cut-off voltage at a certa...

AI Technical Summary

Problems solved by technology

At present, using the load to evaluate the SOH of a single battery is a reliable method recognized in the industry, but this method has some disadvantages: the SOH of the battery needs to be tested offline, which is difficult for vehicle power batteries; the test load is heavy and inconvenient to operate ; If discharge with 0.1C rate, the discharge process will take about 10 hours, the test time is too long

[0006] 2. Internal resistance method

This method has some disadvantages: the research found that when the battery capacity drops by 25% to 30%, the internal resistance of the battery will change significantly, and the standard stipulates that the battery should be removed when the battery capacity drops to 80%. Replacement, so it is difficult to estimate the SOH of the battery in real time by this method, and the internal resistance of the battery is very small, generally in the milliohm level, which belongs to small signals, and it is difficult to accurately measure the internal resistance of the battery

However, this method needs to carefully analyze the internal chemical reactions of the battery, and know some inherent parameters of the battery, such as activation temperature, activation entropy, etc., and a large number of tests on battery life are required before use. The test volume is large, difficult, and time-consuming. also longer

Images