Research On Key Techniques Of Conductive Charge Coupler Of Electric Vehicle

The emerging industry of electric vehicle has entered into the booming period as it is being pushed by the state, which also drives various relevant supporting industries, within which industrial big breakthrough and development have happened, especially in the fields of battery and charging post, which imminently need the charge coupler technology to keep up with the pace and direction of the development of the electric automobile industry. Before the start of this new trend, the development of charge coupler for electric automobile in China had been rather slow, with too many kinds of charge coupler on the market, which are not by a unified standard or of stable quality, consequently pretty unfavorable for the electric automobile industry as a whole to move forward. Although on the international level, the development of charge coupler for electric vehicle in European countries and Japan has started much earlier than that in our country, yet there haven’t been many significant technological breakthroughs in recent years. Of these major players, Europe executes the IEC(International Electrotechnical Commission) standards, the USA operates on SAE(Society of Automotive Engineers) ones, Japan carries on JEVS(Japan Electric Vehicle Standards) and China administrates the standard of Conductive Charge Connectors for Electric Vehicle, i.e., GB/T20234-2011, which was issued and effective in 2011.The GB/T20234 standard was made based on the specific domestic circumstances as well as according to relevant standards, and is able to ensure that there is a unified interchangeability standard for charge coupler from both at home and abroad. In order to meet and adapt to the requirements for the development of the market, it is imperative that we should begin our research on key techniques in search for major breakthroughs. It is currently specified both in domestic as well as international standard systems that the mechanical life of a charge coupler with no live load should be 10000 cycles, the contact resistance should be 0.5 m?, and the temperature rise should not exceed 50 K. The service life of the charge coupler is estimated to be no more than 5 years based on their operation frequency, yet the service time of an automobile is twice as long or even longer.Conductive charge coupler for electric vehicle are taken as the research objects for this project and research has been conducted on the key techniques of these charge coupler, of which the aim is to improve the mechanical life to be more than 20000 cycles, the service time to be over 10 years(approaching that of an automobile), the contact resistance to be below 0.3 m? and the temperature rise to be under 30 K, to reduce the pollution of environment and waste of resources due to the abandonment of faulty coupler, to make the coupler able to work at higher temperatures, and, ultimately, to improve the operating span of core parts and the safety performance of the automobile.The key techniques of charge coupler are mainly reflected in the contact resistance, temperature rise and mechanical life of the contact pair. Systematical and in-depth research and analysis have been conducted in this project on the contact pair, including the structure analysis, electrical and thermal conduction analyses, material analysis, surface engineering technological analysis, friction and abrasion analysis, principle failure mode analysis and reliability analysis of the contacts, which also put forward an original proposal of hyperboloid cage sockets that combine featured structural design innovations with the merits of the commonly used traditional contacts. In-depth research and emulating calculations have been done on various aspects ranging from the hyperboloid cage structure of the sockets, contact resistance, insertion and withdrawal forces to mechanical life, which have been sequentially followed by trial productions as well as a series of tests of the samples, then by the comparison of the measured values and the calculated theoretical ones to the required values. And the result has shown both in theory and practice that the goals of the project have been achieved as what has been anticipated.In this research project, hyperboloid cage sockets have been employed on charge coupler on the basis of standardization, with demonstrated effects of improved safety performance and doubled mechanical life of the charge coupler, hence consequently having adapted to the development direction of charge coupler, furthered this development in China and promoted it to an industry-leading status.