Data Description:
A set of four Li-ion batteries (# 25, 26, 27 and 28) were run through 3 different operational profiles (charge, discharge and impedance) at room temperature (24 deg C). Charging was carried out in a constant current (CC) mode at 1.5A until the battery voltage reached 4.2V and then continued in a constant voltage (CV) mode until the charge current dropped to 20mA. Discharge was carried out using a 0.05Hz square wave loading profile of 4A amplitude and 50% duty cycle until the battery voltage fell to 2.0V, 2.2V, 2.5V and 2.7V for batteries 25, 26, 27 and 28 respectively. Impedance measurement was carried out through an electrochemical impedance spectroscopy (EIS) frequency sweep from 0.1Hz to 5kHz. 

Files:
B0025.mat	Data for Battery #25
B0026.mat	Data for Battery #26
B0027.mat	Data for Battery #27
B0028.mat	Data for Battery #28

Data Structure:
cycle:	top level structure array containing the charge, discharge and impedance operations
	type: 	operation  type, can be charge, discharge or impedance
	ambient_temperature:	ambient temperature (degree C)
	time: 	the date and time of the start of the cycle, in MATLAB  date vector format
	data:	data structure containing the measurements
	   for charge the fields are:
		Voltage_measured: 	Battery terminal voltage (Volts)
		Current_measured:	Battery output current (Amps)
		Temperature_measured: 	Battery temperature (degree C)
		Current_charge:		Current measured at charger (Amps)
		Voltage_charge:		Voltage measured at charger (Volts)
		Time:			Time vector for the cycle (secs)
	   for discharge the fields are:
		Voltage_measured: 	Battery terminal voltage (Volts)
		Current_measured:	Battery output current (Amps)
		Temperature_measured: 	Battery temperature (degree C)
		Current_charge:		Current measured at load (Amps)
		Voltage_charge:		Voltage measured at load (Volts)
		Time:			Time vector for the cycle (secs)
		Capacity:		Battery capacity (Ahr) for discharge till 2.7V 
	   for impedance the fields are:
		Sense_current:		Current in sense branch (Amps)
		Battery_current:	Current in battery branch (Amps)
		Current_ratio:		Ratio of the above currents 
		Battery_impedance:	Battery impedance (Ohms) computed from raw data
		Rectified_impedance:	Calibrated and smoothed battery impedance (Ohms) 
		Re:			Estimated electrolyte resistance (Ohms)
		Rct:			Estimated charge transfer resistance (Ohms)
