【作者】 单忠强；

【导师】 宋诗哲；

【作者基本信息】 天津大学 ， 应用化学， 2007， 博士

【摘要】 镍氢电池作为一种新型化学电源,具有比能量高、无环境污染、良好的循环充放电性能等优点,拥有广泛的应用领域,尤其作为电动汽车的动力电源,进一步提高其综合性能,有着重要的实用价值和意义。本文对镍氢电池负极材料的储氢合金的表面改性和表面处理、用于电动汽车的大容量方型镍氢电池的设计和制备以及利用镍氢电池的内压特性表征电池的循环寿命的方法等方面进行了系统的研究。本论文提出了用电化学的方法在储氢合金电极或储氢合金粉表面包覆镍-非金属非晶态合金的工艺方法。X射线能谱(EDX)测试的结果表明,包覆到储氢合金电极表面的物质为镍-非金属合金。X-射线衍射法(XRD)的测试证明包覆的镍-非金属合金均是以非晶态的形式存在。采用电化学的方法在储氢合金电极表面包覆镍硫合金可以提高电极性能。电化学性能测试结果表明:处理后的电极的大电流放电性能和循环稳定性都得到了一定程度的改善,而在自放电方面,处理后电极的自放电改善情况比未处理电极更为明显。并且,用电化学阻抗法(EIS)、循环伏安法(CV)和X-射线光电子能谱(XPS)等测试手段研究了改善电化学性能的原因。本文采用DNY-2型电池内压测试仪实时、非破坏性地测量镍氢电池的内压。在低倍率充电时,镍氢电池的内压随充电时间的变化曲线可以用Boltzmann函数拟合,且模拟函数中的参数有确切的物理意义。利用Boltzmann模拟函数在拐点附近的变化率k来更准确地预测电池的寿命变化。实验表明,k值越大,在一定充电时间内镍氢电池的内压上升的速率就越快,电池的循环寿命越短。本论文设计和制备了电动车用100 Ah高容量方型镍氢电池,研究了电池使用的正负极材料和结构、电解液组成、电池零部件、高容量方型镍氢电池的化成和分选制度等方面对电池性能的影响。论文还对研制的电池进行了大电流充放电、循环寿命等性能和安全性测试,并进行了电动汽车模拟和试车运行。试验结果表明:采用泡沫镍正极和拉浆负极组成的100 Ah方型镍氢电池的重量比能量超过了75 Wh/Kg, 1/3 C电流下循环放电超过了1000次,在40 km /h的车速下,实车运行超过300 km。更多还原

【Abstract】 Nickel-metal hydride (Ni-MH) batteries are one of the most promising future vehicular power systems because of advantages such as high specific energy, long cycle life, use of no poisonous heavy metals and great improvement of recharge / discharge performance. Extensive efforts continue to be made to develop Ni-MH batteries to meet the stringent requirements of electric vehicles. There are important values of practicality and theory for the further research of improving the comprehensive performance of Ni/MH batteries.The main contents of this paper includes that the surface modification and surface treatment of hydrogen-storage alloy negative electrode materials of Ni/MH batteries, the design and preparation of a kind of rectangle Ni/MH battery with a larger capacity used for vehicular power, and a new method of the cycle life estimation in terms of the internal pressure characteristic of Ni/MH batteries.The electrochemical techniques of encapsulating the amorphous nickel-nonmetal alloy on the surface of hydrogen-storage alloy electrode or hydrogen-storage alloy powder was used in this paper. The surface component of encapsulated nickel-hydride electrodes was measured by energy dispersive analysis of X-ray (EDX), and the analysis of X-ray diffraction (XRD) confirmed that the prepared nickel-nonmetal alloy, such as Ni-S alloy, on the electrode surface had amorphous structures. The electrochemical measurements showed that the large current discharge performance and the stability of cycle life of treated electrodes were improved, and especially, the self-discharge of treated electrodes received an obvious abatement. The related theoretical analysis was given according to the analytical results of electrochemical impedance spectroscopy (EIS), Cyclic Voltammetry (CV), and X-ray photoelectron spectrum (XPS).The internal pressure variations of different Nickel-metal hydride batteries were studied. A DNY-2 was specially designed to measure indirectly the pressure inside the battery shell without damage to any battery parts. The internal pressure variations were simulated by the Boltzmann function when the batteries were charged with a low current density. The parameters in the simulating function have definite physical meanings, and a special parameter k, which is the variability of internal pressure with the charge state or the charge time of the battery in the region of inflexion of this simulation function can be used to estimate the cycle life of batteries. The result shows that batteries with a smaller k value have a longer cycle life.The rectangle Ni/MH battery with a larger capacity of 100 Ah used for vehicular power was designed and prepared. The effects of materials and structures of positive and negative electrodes, the composition of electrolyte, parts of battery, the initial charge / discharge processes, and the select method of Ni/MH batteries on the battery performances were studied. Besides, the tests of charge or discharge with a large current, the cycle life and safety of prepared battery have been finished, and the simulation and run-in tests of electric vehicles also have been done successfully. The results showed a power density of 75 Wh/Kg, cycle numbers of 1000 at a current of 1/3C for the prepared 100Ah battery with foam nickel negative electrodes and sintered positive electrodes. The electric car with the prepared battery was able to run about 300 km at a speed of 40 km /h.更多还原