Lithium-ion battery system for electric vehicles and charging heating method thereof

Abstract

The invention provides a lithium-ion battery system for electric vehicles and a charging heating method thereof. Each high-voltage electrical circuit is provided with two control relays; the problem is effectively avoided that the sharing of relays causes non-uniform lives of relays, and the problem is also effectively avoided that charging or heating fails due to relay adhesion that is due to thesole use of a relay. The charging heating method is characterized in that a current acquired value of a current sensor is detected in real time, charger output current requested by a BMS (battery management system) is adjusted dynamically, and charge current of the lithium-ion battery system is constantly maintained to (-IC+I1) to (-IC+I2) (positive for charge, negative for discharge, and IC forallowable charge current of a current battery module), and therefore, actual charge current exceeding allowable charge current of a battery is effectively avoided. Charging and heating safety is improved from electrical connection and a control method, the service life of each battery is extended, charging efficiency is improved, and battery system stability is guaranteed.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries for electric vehicles, in particular to a lithium-ion battery system for electric vehicles and a charging and heating method. Background technique [0002] In recent years, electric vehicles have been rapidly promoted and applied in my country, and lithium-ion battery systems, as the most important power source of electric vehicles, have also received extensive attention. The performance and use of lithium-ion batteries are not only affected by internal factors such as their own systems, materials, and formulas, but also severely limited by external environmental conditions such as temperature. Especially charging in a low temperature environment not only affects the charging efficiency and shortens the battery life, but also is prone to the phenomenon of "lithium deposition" in the battery. In severe cases, "dendrites" are formed to pierce the battery diaphragm, causing a short circ...

AI Technical Summary

Problems solved by technology

On the one hand, the existing scheme causes the total negative relay to be used much more frequently than other relays, which increases the risk of relay adhesion out of control

On the other hand, at low temperature, part of the output current of the charger may flow into the battery to charge the battery, resulting in low temperature charging of the battery, which affects the safety and life of the battery.

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