Method of estimating battery remaining power in electric vehicle

摘要

A method of estimating remaining battery power in electric vehicles is provided. The method uses coulometric detection method to obtain remaining battery power and uses an open voltage method to modify the coulometric detection method when modified conditions are met as well as different battery characteristics and conditions when in use. The remaining battery power in electric vehicles can conduct a dispersion degree detection at every stage and when a detection value is larger than a preset value, a self-adjusting mechanism will be activated to modify the battery power. When the battery is charged for a longer period of time, a regression method is used to establish a modified equation to increase precision of estimating remaining battery power.

主权项

1. A method of estimating battery remaining power in electric vehicles, comprising steps of:
a first battery power measuring unit obtaining battery remaining power in electric vehicles using coulometric detection method; a second battery power measuring unit obtaining modified battery power using open voltage estimation method; a first modifying unit using said modified battery power to modify said battery remaining power when the battery rests for a certain period of time and battery power difference exists between the battery remaining power and modified battery power; and a second modifying unit utilizing open voltage estimation method to modify coulometric detection method that has accumulating errors to increase precision of coulometric detection method in dynamic measurement, wherein the open voltage estimation method is a modified open voltage method, the method comprising steps of: estimating voltage of a plurality of batteries; selecting a relatively stable sample range among the batteries; weighing, averaging the batteries in the sample range and multiplying total number of batteries; and comparing battery characteristic curves to obtain modified battery power, wherein when the battery is charged for a longer period of time, the modified open voltage method conducts dispersion degree detection, and when a detection value is larger than a preset value, a self-adjusting mechanism is activated to modify the battery power, wherein the dispersion degree detection includes steps of calculating an average power value of all batteries, obtaining the detection value by subtracting each battery power and then adding them altogether, and adjusting the modified open voltage curve when the detection value is larger than the preset value, wherein the dispersion degree detection includes steps of setting a voltage range; gathering statistics regarding batteries not in the voltage range; determining the preset value according to the statistics; and adjusting the modified open voltage curve when the detection value is larger than the preset value.