动力电池内阻检测技术研究

发布时间：2018-08-30 16:42

【摘要】：动力型锂电池目前已经在新能源汽车等领域中得到广泛应用,电池内阻是影响和评判锂电池储能过程中最重要的因素之一,电池内阻的实时变化能够精准地反映出电池的运行状态和健康状态等特性,以检测电池内阻的标准来衡量评估锂电池性能的好坏逐渐得到人们认可。由于测量锂电池内阻阻值范围是在毫欧级别的微弱信号检测,对于检测这样高精度的微弱信号,无论在检测技术上、测量方法上还是在电路设计环节上都要完整可靠地保留有效信号,并且在信号放大和滤波电路中能够滤出工频信号干扰和周围电路的波纹干扰信号等扰动,确保检测信号的精确度在有效范围内。本文从锂电池内阻成因机理分析,根据锂电池内阻由欧姆内阻和极化内阻主要构成,建立电池内阻等效模型,采用基于改进式的四端子交流注入法来检测电池内阻阻值。通过分析电池内阻的化学阻抗谱,确定电池内阻适合的频率段,频率范围在100~10k Hz时,电池内阻的动态变化趋于稳定,便于测量和检测。电池内阻检测系统分别介绍和设计了交流激恒流源模块、差分放大电路、模拟乘法电路、滤波电路、A/D转换模块、主控制电路模块,其中把正弦信号发生器设计单独独立模块,用离散化的方法实现软件中数字滤波的设计,还完成了测试系统软件设计部分,确立程序流程图和完成软件编程。在Matlab中建立模型,对检测的各部分电路模块环节进行调试、对比,来测试检测系统的各项性能指标是否符合标准,对电池内阻进行重复采样检测,并取其平均值和方差来评估电池内阻的波动幅度及稳定性,通过仿真验证,保证设计方案对电池内阻检测误差范围控制在±1.1%,表明本方案有效性和可行性。
[Abstract]:The dynamic lithium battery has been widely used in the field of new energy vehicle and so on. The internal resistance of the battery is one of the most important factors that influence and judge the energy storage process of the lithium battery. The real-time variation of battery internal resistance can accurately reflect the characteristics of the battery, such as the operating state and the health state, and the evaluation of lithium battery performance by measuring the battery internal resistance has been gradually recognized. Because measuring the range of internal resistance of lithium batteries is a weak signal detection at the millimeter level, for detecting such a high precision weak signal, no matter in the detection technology, The effective signal should be kept completely and reliably in the measuring method or in the circuit design, and the disturbance such as the interference of the operating frequency signal and the corrugated interference signal of the surrounding circuit can be filtered out in the signal amplifying and filtering circuit. Ensure that the accuracy of the detection signal is within the effective range. Based on the analysis of the formation mechanism of internal resistance of lithium battery, according to the internal resistance of lithium battery is mainly composed of ohmic internal resistance and polarized internal resistance, an equivalent model of battery internal resistance is established, and an improved four-terminal AC injection method is used to detect the internal resistance of the battery. By analyzing the chemical impedance spectrum of the battery internal resistance, the suitable frequency range of the battery internal resistance is determined. When the frequency range is 100 ~ 10k Hz, the dynamic change of the battery internal resistance tends to be stable, which is easy to measure and detect. The battery internal resistance detection system introduces and designs AC exciting constant current source module, differential amplifier circuit, analog multiplication circuit, filter circuit A / D conversion module, main control circuit module respectively, in which the sinusoidal signal generator is designed as an independent module. The design of digital filter in software is realized by discrete method. The software design part of test system is also completed. The flow chart and software programming are established. Build a model in Matlab, debug and compare each part of the circuit module to test whether the performance index of the detection system conforms to the standard, and carry on the repeated sampling detection to the battery internal resistance. The average value and variance are taken to evaluate the fluctuation range and stability of the battery internal resistance. The simulation results show that the error range of the design is 卤1.1, which shows the effectiveness and feasibility of the scheme.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912

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