Design Of Battery Management System For Fast-charge Plug-in Hybrid Electric Vehicle

With the increasing problem of environmental pollution, especially in recent years with the PM2.5and haze gradually been recognized, fuel vehicles as an important source of urban pollution needs to be improved or replaced. Pure electric vehicles and plug-in hybrid for its energy-saving advantages attract more and more attention to the research and development it, research and manufacture of battery and vehicle power management system occupies an important position; nickel-metal hydride (NI-MH) batteries with advantages of higher energy density and power density, fast charging and well deep discharge performance, high charge-discharge efficiency, maintenance-free, is widely used in hybrid vehicle, because the high cost and uncertain work environment, battery needs battery management system (BMS) to manage the battery status, to ensure battery safety, and to extend battery life, thus reducing the cost of the battery.NiMH battery pack can work in pure electric and hybrid modes, three groups of302V/40Ah battery connected in parallel to make up302V/120Ah battery, analyzed the current mainstream BMS design, the cell voltage and temperature sample circuit are designed. The system uses a master-slave structure, the main board is responsible for the total voltage, total current sampling, SOC calculation, management slave board and communication with the vehicle ECU; the slave boards are responsible for monitoring their own battery pack and communication with the motherboard, the CAN bus are used in communication systems, communication protocol using SAE1939, because of the larger amount of data exchange systems, inside and outside CAN communications are designed; when the battery SOC calculated using Ah integration, overcharge and over discharge, self-discharge and open-circuit voltage correction are used.System operates normally in the real road test, high sampling and SOC precision can meet operational requirements, the battery pack thermal management and the protection mechanism can work properly to ensure the safety of the vehicle.