Method for measuring direct current internal resistance, full charge capacity and remaining power of battery pack

Abstract

The invention provides a method for measuring direct current internal resistance, full charge capacity and remaining power of a battery pack. The method comprises the following step of building a discharge circuit in a battery module, wherein the discharge circuit can be controlled by a switch, and discharge current of a lithium battery is a fixed value in a certain period of time, and is not changed with a system load. The electric capacity of the lithium battery can be easily and precisely derived from the obtained direct current internal resistance.

Description

technical field [0001] The invention relates to a method for measuring the capacity of a battery, in particular to a method for establishing a discharge circuit with a fixed current and measuring the DC internal resistance to obtain the capacity of the lithium battery. Background technique [0002] Batteries can be said to be the source of power for all portable electronic devices, but everything: mobile phones, notebook computers, personal digital assistants, walkmans, etc., all rely on batteries to provide power. Most of the portable electronic devices adopt battery recharging method, that is, use secondary batteries to replenish the originally consumed electric energy. [0003] The aging of secondary batteries, the most commonly seen and the easiest to detect is the change of internal resistance. The internal resistance of the battery core is very small when it leaves the factory, but after long-term charging and discharging, the internal resistance will gradually increas...

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Problems solved by technology

[0003] The aging of secondary batteries, the most commonly seen and the easiest to detect is the change of internal resistance. The internal resistance of the battery core is very small when it leaves the factory, but after long-term charging and discharging, the internal resistance will gradually increase until the internal resistance is large. The power inside the battery cannot be released normally, and the relative battery capacity will also decrease. Most aging batteries cannot be used due to excessive internal resistance.

[0005] Secondary lithium batteries have been used everywhere in recent years. Although lithium batteries have many advantages, all lithium batteries have a disadvantage that they are afraid of overcharging and overdischarging. If they are overcharged or short-circuited, the temperature of the battery will rise and damage the battery. structure, which may eventually cause the battery to explode

[0014] However, the method used by Texas Instruments (TI) is based on the system load current I LOAD to obtain the DC internal resistance measurement technique, but due to the system current I LOAD With variability and instability, the data obtained by this method is complex and difficult to analyze to obtain accurate results

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