Research On The Machining Technique Of Ultrcapacitor Electrode

The machining of ultracapacitor electrode is one of the key techniques in the manufacture of ultracapacitor. Ultracapacitor contains carbon-aluminum-carbon material. The once-forming machining quality is the main factor to influence the voltage-maintaining characteristic of the ultracapacitor. The electrodes formed by traditional punching have the shortcoming of burrs, folded edges and non-insulation on the sides. Those will lead to the over centralization of electric field, break or decrease the insulation of the interlayer, cause the worse leakage current and depress the self discharge characteristic. Besides, the stability and the finishing ratio of ultracapacitor are influenced and its popularization and application will be limited. Therefore, the machining of ultracapacitor is in dire need of solution and it is very important to search for the efficient process.First, the new domestic and overseas developments on the machining of ultracapacitor is analyzed in this article, and a method using gas mixed WEDM to machine ultracapacitor electrode is presented. The processing experiments of ultracapacitor electrodes are carried out on a Slow WEDM machine and a Fast WEDM machine. The influence of the electro-parameters and the non-electro-parameters on the processing of gas mixed WEDM are studied on the basis of the experiments, and the technique rules are analyzed and summarized.With the observation and examination on the machined surface by Scanning Electric Microscope, it is found out that the removing of ultracapacitor material is the course mainly consists of melting, evaporating. The collector part(aluminum) of ultracapacitor occurs oxidation-deoxidization reaction in the WEDM course, which forms alumina insulation film to prevent the leakage current. There is no burr or folded edge occurring on the machined surface of ultracapacitor electrode, which often appears in traditional punching process. The machined surface is quite flat. After examination and comparison between the voltage and current waveforms of machining on metal and ultracapacitor electrode by gas mixed WEDM, it is found out that the discharge maintaining voltage with ultracapacitor electrode is higher. In the machining course, the short circuit ratio and the no-load ratio are higher, too. There are normal discharge and...