Research on the Influence of Stray Parameters in the Circuit of the Hybrid Energy Storage
In the course of battery discharge in hybrid energy storage, overvoltage trends to appear at opposite ends of the IGBT (Insulated Gate Bipolar Transistor) when the IGBT is switched off, which is likely to cause overvoltage to damage the IGBT. To solve the problem, this paper has made analyses of the mechanism of capacitor when overvoltage caused by the IGBT failure, the stray inductance in the hybrid energy storage circuit and the inductance of switch-off current on the overvoltage. And the corresponding mathematical formula is derived. On the basis, a simulation model is established. The rational distribution and the addition of an absorption loop can reduce the peak value of overvoltage. It is found from simulations that the absorption circuit will lead to voltage oscillation in the main circuit. Aimed at this phenomenon, the design of the absorption loop is optimized. Simulations and experiments prove the proposed method to be effective.
Research on high rate discharge for lithium ion battery
This paper researched on high rate discharge performance in lithium ion battery. Battery design influenced on the high rate discharge performance sincerely, then a new design about lithium ion battery came forth. The electrode material ingredient, surface density and thickness of electrode were researched. This paper found a favorable high rate discharge performance lithium ion battery, which had high discharge capacity, flat voltage, preferable cycle performance and low temperature when discharging. A rule on discharge capacity was found, and a charge and discharge system for high rate discharge lithium ion battery was recommended.
Geological, mineralogical and chemical characterization of Devonian kaolinite-bearing sediments for further applications in the ceramic (tiles) industry in La Paz, Bolivia
Clay minerals are widely distributed in Bolivia; among them, illitic clays are most common in the Altiplano where they are mined for use in the ceramic industry that has been growing in the last few years. In addition to illitic sediments, kaolinitic sediments have been recently discovered in sedimentary units in the Bolivian Altiplano. Residual ball clay occurrences in Devonian sedimentary units were studied as part of this work. Geological mapping and geophysical studies (ERT and GPR) were done for better understanding the origin of the deposits and were part of a preliminary study of the mineral potential to define the relationship with the host rock. Chemical and mineralogical techniques such as X-Ray Diffraction, Scanning Electron Microscopy and Inductively Coupled Plasma analyses were performed in samples from the studied area to verify the presence of kaolinite. Atterberg limits and behaviour of the raw material in ceramic specimens supported by chemical analyses show that this material is suitable for manufacturing tile ceramics. This study provides fundamental knowledge for deposit exploitation and future generation of an alternative source of employment for the inhabitants of Micaya.