A Method for Predicting the Residual Discharge Energy of a Series Battery Pack Used in Electric Vehicles

Abstract

The invention relates to a method for predicting residual discharge energy of a series battery pack for an electric vehicle, and belongs to the technical field of electric vehicle battery management. First, collect the operating condition data of the battery pack to predict the future output power and temperature change rate of the battery pack; then identify the internal resistance parameters of the equivalent circuit model of the battery pack and the single cell with the lowest voltage, and update the internal resistance of both. The curve of parameters changing with their respective states of charge; then determine the state of charge prediction interval, calculate the future state of charge sequence of the battery pack and the single cell with the lowest voltage; and predict the future voltage sequence, future current sequence of the battery pack, and The future temperature sequence and the future cell voltage sequence of the cell with the lowest voltage; finally, the remaining discharge energy of the battery pack is calculated. The method of the present invention takes into account the impact of the inconsistency of the state of charge of each cell on the discharge cut-off time of the battery pack, and can accurately predict the remaining discharge energy of the series battery pack.

Description

technical field [0001] The invention relates to a method for predicting the remaining discharge energy of a series battery pack used in an electric vehicle, and belongs to the technical field of electric vehicle battery management. Background technique [0002] At present, electric vehicles have problems such as short driving range and inaccurate estimation of remaining mileage, which cannot fully meet the needs of users, and will cause drivers to have "range anxiety". The power source of an electric vehicle is generally composed of several single power batteries in series. The discharge energy of the battery pack directly affects the driving range of the vehicle, and the prediction accuracy of the remaining discharge energy of the battery pack has a great influence on the estimation accuracy of the remaining mileage of the vehicle. , need to focus on research. [0003] The remaining discharge energy of the battery pack is the accumulated energy released by the battery pack...

AI Technical Summary

Problems solved by technology

[0004] At present, there are some methods that regard the series-connected battery pack as a whole, do not consider the inconsistency between the cells, simply use the prediction method of the remaining discharge energy of the single battery to predict the remaining discharge energy of the battery pack, and the prediction accuracy cannot meet the needs of the vehicle

When there is a large difference in the state of charge between the cells, the predicted discharge cut-off time of the battery pack is much later than the actual discharge cut-off time, resulting in an overestimation of the remaining discharge energy of the battery pack, which further leads to an overestimation of the remaining mileage of the electric vehicle. In severe cases, it may lead to insufficient mileage of electric vehicles during the journey, and "squat" in the middle of the journey, seriously affecting the user's travel plan, and more likely to lead to safety accidents

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