Electric automobile rapid charging system and method

Abstract

The invention relates to an electric automobile rapid charging system and method. The electric automobile rapid charging system comprises a power battery pack, a battery management system, a charginginterface, a charging positive electrode relay, a charging negative electrode relay and a structure conversion relay set. Through combination of closing states and disconnecting states of a pluralityof structure conversion relays in the structure conversion relay set, the series-parallel connection structures of battery units in the power battery pack are changed, the battery management system controls switching of the closing states and the disconnecting states of the charging positive electrode relay, the charging negative electrode relay and all the structure conversion relays the structure conversion relay set according to the upper limit of the charging voltage; and by changing the series-parallel connection structures of the power battery pack, on the premise that the charging current is not increased, the charging power is effectively improved, the charging time is shortened, meanwhile, the service life of the lithium ion battery is prolonged, the safety of the lithium ion battery is improved, the risk of early aging or overheating, caused by large-current charging, of the lithium ion battery is reduced, and safe and rapid charging of the power battery pack is realized.

Description

technical field [0001] The invention relates to the technical field of charging electric vehicles, in particular to a fast charging system and method for electric vehicles. Background technique [0002] Electric vehicles use electric motors as driving devices, and are powered by on-board rechargeable batteries or other energy storage devices. They have the advantages of zero emissions, high efficiency, quietness, smooth operation, easy driving and operation, low maintenance costs, and a wide range of required power sources. Therefore, in the existing new energy vehicle technology, it is regarded as a long-term development goal. [0003] The energy storage devices commonly used in electric vehicles are battery packs (hereinafter referred to as battery packs), commonly used such as lithium-ion battery modules, etc., but due to the characteristics of the battery and the limitations of charging facilities, the charging time is too long compared to the refueling of traditional fu...

AI Technical Summary

Problems solved by technology

The charging current of the battery during fast charging is 1C or 2C, and can even reach 5C or even 8C. Due to the limitation of switches and other devices, excessive charging current will lead to overheating of the charging system, increased cable weight, reduced system reliability and even potential safety hazards. Therefore, it is difficult to continue to increase the output current of the charging device, and the charging time is longer

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