The Research And Design Of Battery Management System Based On Can Bus Technology

In order to deal with energy crisis and environmental pollution, many countries have focused on the development of new energy technology. As an emphasis in the future, Pure Electric Vehicle is developing very fast. But the power battery is a bottleneck for the electric vehicle’s development. Battery management system can ensure the security of battery pack, promote the efficiency of battery pack and extend the life span of battery.This paper firstly introduces the development of electric vehicle and power battery and illustrates a design plan of a system combining the centralized and distributed methods. This system which contains a main module and several subordinating modules, realizes the communication among these modules by CAN bus. This paper mainly accomplishes the following tasks:(1) By contrast demonstration, the paper realized the battery state of charge SOC estimation and battery equalization control. SOC estimation of this system combines the ampere hour measurement method and the open circuit voltage method; considering of the practical situation, battery equalization module applies discharge passive balancing methods.(2) Realizing the multiple alarm mechanism and protection function. Sound and light alarm is involved in the system. At the same time, the system uploads the message and stores them; the function of protection and control consists of over-charge, over-discharge, over-current and over-heat protection.(3) Realizing the collection of battery monomer information by the battery monitoring module LTC6803. the main control module through the control circuit realizes the insulation of resistance data and the total voltage data. We can easily estimate the SOC and develop the management strategies.(4) The part of historical data processing involves multi-level buffer and fault tolerant mechanism which saves the message coming from the subordinating chip in SD memory card.(5) CAN correspondence is the connection of the entire data exchange of the system. This paper illustrates the design for hardware and software. The part of software includes underlying drivers and protocol layer.Although this paper aims at the research on battery management system, there are still many problems in practical application. Some breakthroughs are needed to be seen in the future, for example, the improvement of SOC estimation for battery remaining capacity, the promotion of battery balance strategy and the problem of BMS versatility.