Development of High-performance Electric Double Layr Capacitor for Recovering/Reusing Inertia Energy of Heavy Vehicles

点击翻译按钮获取中文摘要

Aiming at realizing a hybrid diesel car equipped with electric double layr capacitor (EDLC) made of activated carbon electrodes as an inertia energy recovery device, which can reduce environmental pollution significantly, we examined performance of the capacitor both for static and dynamic nature. Summary of the research follows below.1.Experimental system : We developed an experimental system and a method to obtain static and dynamic nature of EDLC separately, which cannot be made with the constant-current charge-discharge method of common use.2.Static performance : Static capacities of EDLC's composed of several activated carbons with various pore characteristics and with various surface characteristics were measured. Increase in specific surface area did not directly result in a linear increase in static capacity. Rather, the surface area showed only a slight influence to the capacity. On the other hand, it was the surface oxide groups that gave significant increase in the static ca … More pacity.3.Dynamic performance : Transient processes of charging/discharging EDLC was measured and analyzed with a model that includes an "effective conductivity" for various combinations of carbons and electrolytes. The effective conductivity was found to increase significantly if the pore width of electrode exceeded ca.0.7nm. This result implies that ionic species move as their hydrated states, whose sizes are around 0.7nm, and that the movement of the ionic species are sterically hindered by pore geometry if the pore width is smaller than a critical size. The crucial importance of pore characteristics of electrode carbon was thus found and confirmed.4.Total performance : The EDLC suitable for rapid charge/discharge should have pore width of 0.8-0.9nm and surface oxide groups. Higher degree of activation would give only slight increase in static capacity, and lower degree of activation would result in a drastic decrease in dynamic responsibility. One has to, however, pay attention to the stability of surface oxide groups on activated carbon, detail of which has not been clarified so far. Less