Cell management system of electric automobile

Abstract

The invention discloses a battery management system of an electric vehicle, which comprises a primary vehicle-body system, a main controller and a battery pack, wherein, the battery pack is formed by more than two batter modules connected in series, the batter modules are formed by connecting more than two single cells in series, each battery module is provided with a battery collecting module, the battery pack is respectively connected with a complete vehicle power system through a discharging relay and a charging relay, the main controller is connected with a previous complete vehicle system through a first optical isolator, and the battery collecting module is connected with the main controller through a second optical isolator. The battery management system has the advantages that: as the battery management system is composed of the main controller (BMU) and the next battery collecting module (LECU), the composition of the system structure is simplified through the main controller and the next battery collecting module, the cost of the hardware of the system can be reduced, and simultaneously, the reliability of the management system can be greatly enhanced.

Description

technical field [0001] The invention relates to an electric vehicle management system, in particular to an electric vehicle battery management system. Background technique [0002] With the frequent shortage of non-renewable energy sources such as electricity, coal, and oil, energy issues have increasingly become a bottleneck restricting the development of the international society and economy. More and more countries have begun to implement "green new energy plans" to seek new impetus for economic development. The development of electric vehicles is an inevitable trend of history. At present, there are mainly four types of power batteries for electric vehicles: lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries and lithium batteries. Because lithium batteries have the advantages of high working voltage, large specific energy, long cycle life and no pollution, they are the best choice for electric vehicles. The main direction of development, but t...

AI Technical Summary

Problems solved by technology

[0004] 1: Use a battery monitoring module for each single battery to monitor the battery pack. This method will result in a complex and large system, poor reliability, and inapplicability. It is also not conducive to network communication.

[0005] Two: The calculation method of the remaining capacity (SOC) of the battery management system basically uses the difference between the cumulative charging capacity and the cumulative discharging capacity, so the calculated error is large and the error will increase with the increase of use time

[0006] Three: The balance between batteries in the battery management system adopts an external independent balanced charging method. This method is only suitable for small-capacity batteries, and the external wiring and operation are complicated. It is impossible to achieve high-current fast charging of electric vehicles. In electric vehicles It is almost not used, this method is only suitable for regular battery maintenance

[0007] Four: The battery management system does not have the function of automatically setting the charging of the battery, that is, it cannot determine a reasonable and feasible charging current according to the current remaining capacity of the battery, which will easily cause the battery to be overcharged or cannot be fully charged.

[0008] Five: The single voltage and temperature alarms of the batteries in the battery management system adopt a first-level alarm method, which can easily cause battery damage caused by the user being caught off guard and unable to perform first aid.

[0009] Six: The battery management system does not have the insulation performance test of the battery pack. Due to the high voltage of the battery pack (385V) and the poor working environment, if there is a battery pack leakage, it will bring great danger to personal safety.

[0010] Seven: The battery management system does not have any predictability for the detection and maintenance of the battery pack, that is, it is impossible to see the current working conditions of each single battery in the battery pack, which is not conducive to the debugging and maintenance of the battery pack

[0011] Eight: RA485 or parallel communication is mostly used in battery management system communication, which affects the speed and reliability of data communication

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