Secondary cell capacity estimation method

Abstract

The invention provides a simple method to solve the problem of inaccurate estimation of the secondary battery capacity. By estimating the remaining capacity of the battery before the cut-off of charge and discharge, the battery capacity is calculated at the final charge and discharge termination stage and smoothly approaches the set value according to the set trend value, which actually reflects the real use status of the battery in a system. The system can accurately know the battery condition and make the necessary response, and at the same time, the factors of battery aging are included in the calculation of the remaining capacity, so as to accurately obtain the fully charged capacity of the battery.

Description

technical field [0001] The invention relates to a method for calculating the remaining capacity of a secondary battery, which is suitable for the actual use of the secondary battery in various systems. Background technique [0002] First of all, let’s make a brief description of the current method of estimating the remaining capacity of the battery, such as figure 1 Shown is a battery-powered system, which includes an ADC (analog-to-digital conversion) unit (2) connected to the battery to read the voltage, current and temperature of the battery, a battery pack unit (1) to provide system power, and a micro The processing unit (3) can read the voltage, current and temperature of the battery, calculate the remaining capacity of the battery, and an operating device (4) can provide battery charging power and discharge load; the ADC measures the battery (charging and discharging, standby, Voltage (V), current (I) and temperature (T) at any time, another micro-processing IC can ca...

AI Technical Summary

Problems solved by technology

However, it is not easy to measure the accurate internal resistance, and it is easy to interfere with the charging and discharging procedure. At the same time, it takes a lot of time to do experiments in advance to obtain the table of the relationship between the internal resistance and the remaining capacity of the battery.

[0009] In addition, for systems that do not require accurate calculation of the remaining capacity of the battery, the battery capacity is often represented by the number of grids. For example, a total of four grids and one grid represent 25% and all four grids are fully lit. The method is to compare the capacity ratio with the battery voltage during discharge. For example, 4.2V represents 100% of a general lithium battery, and 3.0V represents 0%. It does not take into account changes in the internal resistance of the battery aging, current, and temperature changes. Therefore, the accuracy of the remaining capacity has a large error, which causes inconvenience in use.

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