Lithium battery charge and discharge characteristics calibration method and charge and discharge characteristics calibration instrument

Abstract

A method for calibrating the charging and discharging characteristics of a lithium battery, comprising: 1. Charging the lithium battery to be tested with a constant current, when the battery voltage reaches the rated maximum voltage, the charging ends, and according to the calculated electric quantity at the end of the charging, in the formula, t1 is the charging completion Time, i is the charging current, η is the battery efficiency coefficient, where η=ηT×ηt×ηi, ηT is the temperature influence coefficient, ηt is the aging coefficient, and ηi is the charge-discharge rate coefficient. When the lithium battery to be tested is discharged, when the real-time voltage reaches the rated minimum voltage, the discharge ends, and the maximum charge capacity Q2 is obtained according to the calculation. In the formula, i is the discharge current, t2 is the time when the discharge ends, and η is the battery efficiency coefficient. According to Q1 and Q2, the initial state of charge of the battery is calibrated and the charging voltage-SOC function curve is drawn. This calibration method is implemented in the provided charge and discharge characteristic calibration instrument. The calculation result of the method is accurate, and the application range is wide. The provided charging and discharging characteristic calibrating instrument has simple circuit, compact equipment and simple operation.

Description

technical field [0001] The invention specifically relates to a calibration method for charging and discharging characteristics of a lithium battery and a charging and discharging characteristics calibrating instrument used for implementing the method, belonging to the field of lithium battery measurement. Background technique [0002] Compared with ordinary lithium batteries, lithium iron phosphate batteries have the advantages of high voltage, strong over-discharge capability, long cycle life, good safety performance, less self-discharge, and fast charging. Lithium iron phosphate batteries are more and more used in Electric vehicles, electric tools, toys, portable medical equipment, warning lights and other mobile devices. [0003] In order to protect mobile devices and prolong battery life, it is usually necessary to establish a battery management system to manage lithium iron phosphate batteries. The establishment of the battery management system needs to accurately esti...

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Problems solved by technology

However, this method lacks the judgment of the aging state of the battery. It is considered that the maximum charging capacity of the battery is the rated power, and the battery that has been placed for a long time or used in an extreme environment usually has a maximum charging capacity that cannot reach the rated power. The SOC measured by the battery has a large error, which lacks reference value for the establishment of the battery management system

Moreover, this method only detects the state of charge, and cannot provide a voltage-SOC curve, and the information on the charging and discharging characteristics of the battery is not comprehensive.

In addition, the volumetric instrument used in this method is large in size and difficult to share with environmental equipment such as incubators, and there is no treatment method for measurement errors caused by ambient temperature

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