Power battery state of health on-line monitoring method

Abstract

The invention provides a power battery state of health on-line monitoring method. Based on the common charging voltage interval of the power battery, a charging energy value is extracted to be used as the health indicator of the battery. Under each temperature condition, only one group of offline battery aging data is required to establish a relation between the charging energy value and the battery state of health. Required complicated calculation is the offline non-linear fitting of the relation between the charging energy value and the state of health, and a fitting model can be directly used in an online way.

Description

technical field [0001] The invention relates to the field of power battery prediction and health state management, in particular to a model for power battery prediction and health state management, and a power battery health state online monitoring method based on the model. Background technique [0002] In the practical application of power batteries, their state of health (SOH) is generally characterized by capacity. The capacity of the power battery decays continuously with the charge and discharge of the battery. When it decays to 80% of the initial capacity, the stability of the power battery gradually deteriorates, while the capacity decay becomes faster as the charge and discharge progress. Therefore, it is generally considered that a failure occurs when the power battery capacity decays to 80%. At this time, the battery needs to be replaced or maintained to prolong the service life of the battery and avoid equipment failure. [0003] SOH estimation methods for power...

AI Technical Summary

Problems solved by technology

For the above-mentioned first type of method, although it can estimate the aging state of the battery based on the current, voltage and temperature measured online, the open circuit voltage (Open circuit voltage: OCV) and battery state of charge of the required power battery under different aging state conditions (State of charge: SOC) requires offline calibration

At the same time, this type of method has complex algorithms and high calculation costs, making it difficult to apply online

The second type of method has certain advantages over the first type of method, but because the battery voltage response is greatly affected by the load current, in practical applications, such as in electric vehicles, there are also discharge currents that will change drastically with changes in driving conditions change defect

The application of all these studies needs to be based on the voltage value in the whole charging range, which requires the battery to be used during use and discharged to the low cut-off voltage value of the battery before charging. However, this use condition is not necessarily satisfied.

Images