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Ragone plot – Electrochemistry & Battery – Application Note 6

Latest updated: May 6, 2020


Both primary and secondary batteries are often tested in terms of energy and power density, as well as, the relationship between the two. Ragone plot is a well accepted way to display it. Application note #6 discusses how to use the Constant Power Discharge (CPW) technique available in EC-lab and BT-lab software for Bio-Logic potentiostats-galvanostats-ZRAs and battery cyclers, to obtain this data in a quick and user-friendly manner.



The aim of this document is to describe the Constant Power (CPW) technique. This technique, available with EC-Lab® software (since V8.10), is applied in a Li-ion battery test and is available with all Bio-Logic instruments.

The Constant Power technique has been designed to study the discharge (eventually the charge) of a battery or a cell (made of intercalation compounds) at successive constant power. The constant power control is made by holding the power (i.e. the factor E*I) to a constant value. During the discharge, the cell potential decreases. In order to hold a constant power, the current is adjusted and will increase. This can be shown on the following figure…


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