Research On The Fast Charging Technology Of Electric Vehicle Lithium-ion Battery

The development of electric vehicle industry can’t be separated with the development of related support industries and technology, especially with the development of power and energy technology. These technologies will affect the driving range of electric vehicles, which has an effect on the promotion of electric vehicles. Lithium-ion battery as the extremely main power supply equipment for electric vehicle. Currently the common method of charging is under the premise of guaranteeing to charge into electricity, cycle life and safety. And it can’t meet the needs of the fast charge still. Therefore, search for a method of efficient, fast, safety, reliability and ensuring the performance of the battery, which in order to provide a favorable protection and promotion of the use of electric vehicles.The topic chose lithium iron phosphate in lithium-ion batteries as analysis object, by analyzing the lithium-ion battery’s charge and discharge principle, combined with the specific 3.2V/10 Ah single to do experimental analysis for battery’s charging and discharging performance, learn battery’s exhibited characteristics at different charge discharge rate, analysis polarization’ influence on the battery’s charge and discharge. Integrate battery performance, polarization and fast charging theory Maas Three Laws to study Lithium-ion battery charging method, analyzed on the strengths and weaknesses of common charging method, presenting a fast and efficient way of charging, a negative pulse fast charging method. Compare 1.8C and 1C constant voltage charging mode with a negative pulse fast charge mode, verify the feasibility of the negative pulse fast charging method.In order to achieve better control for charge current and the negative pulse discharge current during charging, this paper presents two sets of fuzzy controller to control the charging current and the negative pulse discharge currents, the results show that the fuzzy controller design better control of the charge and discharge currents at different stages of the charging process. To further clarify negative pulse amplitude and width of the discharge current in the negative pulse fast charging method, do related experimental research for discharge negative pulse amplitude and width of this method through the existing Stropower battery test platform. Compare of experimental data analysis, summarize the results of the exact parameters of the negative pulse discharge, the discharge of the negative pulse amplitude is 5A, the pulse width is 7s.Compare specific negative pulse fast charging method with commonly used three-stage charging method for charging and discharging experiment, the results show a negative pulse fast charging method using 2604 s, charging 10.253 Ah, discharge capacity 9.098 Ah, charging efficiency 88.74%. Under the premise of ensuring the battery charge and discharge electricity, the charging efficiency and cycle life, save 1583s(37.81%) comparing negative pulse fast charging method with the three-stage charging method on charging time. Therefore, the lithium-ion battery with a negative pulse fast charging method is a reliable method for fast charging, this method has some practical value.