Design and implementation of a charge-protection circuit for Lithium-ion capacitors for WIMEA-ICT project

Abstract

Lithium Ion Capacitors have found application in Automated Weather Stations for example in the WIMEA-ICT project. Because they are a relatively new technology, there is currently no analogue all-in-one charge-protection circuit design to prevent over charge/discharge. Therefore, this project’s main objective was to design and implement a charge-protection circuit to regulate the voltage within the range of 2.2V – 3.8V. The methodology was divided into four phases which include; Planning of the project, design and simulation of the hardware, fabrication of the hardware and PCB fabrication. The key results were that below 2.2V the LIC charged and the load was shut down, in between 2.2V to 3.8V the LIC charged and above 3.8V the LIC stopped charging. It is recommended to use high-fidelity comparators which give exact values at a given threshold unlike the general purpose omparators that were used for this project.

Finally, a device which ensures that the LIC charges below 2.2V, between 2.2V to 3.8V and stops charging above 3.8V thus safe operation of the LIC was designed. A Printed Circuit Board (PCB) was also designed, and I believe that many of them can be manufactured and sold at a price of a charge protection circuit of Lithium-ion batteries.