What is high energy composite tantalum capacitor
What is high energy composite tantalum capacitor
High energy composite tantalum capacitor (referred to as high energy tantalum) is a composite of tantalum electrolytic capacitor and super capacitor. High energy refers to high energy density, which is between supercapacitor and electrolytic capacitor; Composite refers to the composite of super capacitor and electrolytic capacitor. High energy tantalum has both the large capacity of supercapacitors and the high withstand voltage of electrolytic capacitors.
The structure of high-energy tantalum is a series combination of an electrolytic capacitor and a super capacitor. The model diagram is as follows:
Among them, super capacitors are subdivided into double layer capacitors, pseudo capacitors and hybrid capacitors.
The commonly used negative electrode material of high-energy tantalum is ruthenium dioxide (RuO2), and its charge and discharge process is Faraday process (that is, the amount of chemical reaction caused by the passage of current is proportional to the amount of electricity passed). Therefore, high-energy tantalum is precisely a composite of electrolytic capacitor and pseudo capacitor.
Due to the existence of material impedance, heat is generated during the charging and discharging process of the capacitor. In actual use, the ripple current should be controlled within the rated range to prevent the final failure of the capacitor due to heat accumulation. The relationship between the capacitance heating power P and the capacitance equivalent series resistance ESR is p = U2 / ESR. The control of ripple current by Evans company is calculated by the following formula:
The influence of ripple current on the capacitor can be monitored by the surface temperature rise.
Based on the characteristics of high-energy tantalum, such as large capacity, high energy density, no charge and discharge times limit, and long service life, it is usually used in power management system, pulse current, power down protection and other circuits. It has been applied in military fields such as UAV, phased array radar and missile power module.