Detecting method and system for health state of extended-range electric vehicle power battery

Abstract

The invention discloses a detecting method and system for the health state of an extended-range electric vehicle power battery. The detecting method includes the steps that the environment temperature and environment humidity of the environment where an extended-range electric vehicle is located are obtained; the temperature of the power battery is obtained; traveling environment information of the extended-range electric vehicle is obtained; a first accumulative charging capacity sequence corresponding to the environment temperature, the environment humidity, the temperature of the power battery and the traveling environment information is obtained from a first battery capacity fading table; the first health state of the power battery is calculated according to the first accumulative charging capacity sequence. According to the detecting method and system for the health state of the extended-range electric vehicle power battery, factors affecting performance states and cycling life of the power battery are considered, so that the obtained health state value is more accurate, and stable and reliable work of a battery pack can be ensured.

Description

technical field [0001] The invention relates to a control technology for an extended-range electric vehicle, in particular to a method and system for detecting the health state of a power battery of an extended-range electric vehicle. Background technique [0002] Power batteries are the core power source of electric vehicles. During use, the capacity of the batteries continues to decline, and the performance gradually deteriorates. The indicator that reflects the battery performance is the remaining battery capacity (SOC, State of Charge). SOC is generally calculated by the ampere-hour integration method. The specific calculation formula is Among them, Q M Represents the current capacity of the battery, i represents the charging and discharging current of the battery, and t is the working time of the current battery. [0003] However, the performance state and cycle life attenuation of the power battery are not only related to the electrochemical system of the battery it...

AI Technical Summary

Problems solved by technology

The disadvantages of this calculation method are: firstly, it is necessary to test the SOH of the battery offline, which is difficult to realize for the vehicle power battery, the test load is heavy, the operation is inconvenient, and the regular capacity test of the customer’s car cannot be realized, which brings great inconvenience to the user. It is very inconvenient; in addition, the SOH calculated according to this method does not take into account the above-mentioned factors that affect the performance status and cycle life of the power battery, and cannot accurately reflect the current real-time health status of the battery, resulting in inaccurate SOH estimation

The disadvantage of estimating SOH through the above-mentioned internal resistance method is that the internal resistance of the battery will change significantly when the battery capacity drops by 25% or 30% after research, and the standard stipulates that when the battery capacity drops to 80%. The battery should be replaced, 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, and it is difficult to accurately measure the internal resistance of the battery

In addition, the SOH calculated according to this method does not consider the above-mentioned factors that affect the performance status and cycle life of the power battery, and cannot accurately reflect the current real-time health status of the battery, resulting in inaccurate SOH estimation.

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