【作者】 徐伟；

【导师】 刘和平；

【作者基本信息】 重庆大学 ， 电气工程， 2010， 硕士

【摘要】 动力电池是电动汽车的核心能源,磷酸铁锂电池以高安全性、动力、环保及长寿命而成为电动汽车动力电源的最佳选择。然而,对磷酸铁锂动力电池的充电方法的研究目前不是很多,将其应用在电动汽车上也还存在较多的工程问题未解决。论文以此为背景,具体完成了以下工作:论文根据磷酸铁锂电池组充电技术要求,搭建了充电实验平台,设计了充电实验平台的CAN网络和监控单元。监控单元主控制板与充电机和电池管理系统通过CAN网络通信。主控制板利用CAN总线对充电机的充电方法进行控制,并利用串口完成了与上位监控程序的通信。对磷酸铁锂电池充电特性和充放电机理进行了分析,完成了磷酸铁锂单节电池和串联电池组的大量充电实验。在实验的基础上,采用了一种基于模糊控制的恒单节电池充电电压上限值的电池组串联充电方法。该方法可以有效地对单节电池进行过充保护。考虑到单节电池在串联充电时,电池之间的不一致性会逐渐加剧,为了保证电池使用寿命只有降低电池组的利用率。均衡充电,作为减小电池组特性不一致性的有效方法,可以均衡电池的特性,从而提高电池组的使用率和显著延长电池组寿命。论文在分析了目前各种均衡充电方案的基础上,设计了一种先用主充电机充电,再用均衡充电模块对单节电池补充充电的均衡方案。对均衡充电模块的主电路、控制驱动电路以及均衡充电模块的软件进行了设计。同时搭建了实验电路,给出了均衡充电模块的实验波形,在实验电路的基础上完成了对电池组中未充满电池的补充充电,验证了该方案的可行性。更多还原

【Abstract】 Power battery is the core energy of Electric Vehicle. Lithium iron phosphate battery is the best choice of power battery because of its high security, power, environmental protection and long life. However, the research on charging methods of lithium iron phosphate battery is just starting up and there are still many unresolved problems in engineering application of Electric Vehicle.In this background, following work has been completed:A charging experimental platform has been built based on the charging requirements of Lithium iron phosphate batteries. Relative CAN networks and monitoring unit also have been designed. Main control panel of monitoring unit communicates with both charger and battery management system through the CAN networks. It controls charging methods of charger and uses serial interface to complete the communication with upper computer.The charging characteristics and mechanisms of lithium iron phosphate battery have been analyzed, and a large number of charging experiments on a single cell and series of lithium iron phosphate battery have been completed. Based on these experiment results, a charging method about which the single cell upper limit voltage is constant based on fuzzy control has been proposed. The method can conduct overcharge protection on each single battery.Taking into account of a single cell in the series charging, the inconsistency among batteries will gradually increase. In order to ensure the life of batteries, only reduce utilization of batteries. Equalization charging, as an effective way to reduce the inconsistency of batteries, balances the characteristics of batteries, thereby improving utilization of battery and significantly extends battery life. After analyzed many schemes about Equalization charging,a balance scheme which first charging with the main charger, and then charging with a equalization charging module has been proposed.The main circuit, control circuit and the software module of equalization charging module has been designed. A test circuit also has been built, the experimental waveforms of equalization charging module in the experimental circuit have been given. Based on the experimental circuit, a experiment of charging a not being fully charged cell of batteries has been completed, which demonstrated the feasibility of this scheme.更多还原