A fast charging system and method for electric vehicles

Abstract

The invention relates to a fast charging system and method for an electric vehicle. The system includes a power battery pack, a battery management system, a charging interface, a positive charging relay, a negative charging relay, and a structure conversion relay group. Multiple structures in the relay group are changed through the structure The combination of closed and disconnected states of the conversion relay changes the series-parallel structure of the battery cells in the power battery pack, and the battery management system controls the closing, closing, Disconnect state toggle. By changing the series-parallel structure of the power battery pack, the charging power can be effectively increased without increasing the charging current, the charging time is shortened, the life and safety of the lithium-ion battery are improved, and the lithium-ion battery is reduced due to high current charging. Therefore, the risk of premature aging or overheating phenomenon is caused, and the safe and fast 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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