"Experimental Dataset of retired batteries (first-life, second-life and third-life) discharged at constanst load rate"

"This dataset provides 120 experimental data from five discharge tests conducted on six retired lithium-ion batteries, which were classified into two groups according to their state of health (SoH). These groups represent different stages of battery lifespan:Group 1: Second-life batteriesCell 001: 1870mAh (SoH: 85%)Cell 002: 1804 mAh (SoH: 82%)Cell 003: 1320 mAh (SoH: 60%)Group 2: Third-life batteriesCell 004: 990 mAh (SoH: 45%)Cell 005: 530 mAh (SoH: 24%)Cell 006: 490 mAh (SoH: 22%) For each cell, nine discharge experiments were carried out using different constant load rates ranging from 1 \u03a9 to 3 \u03a9, with increments of 0.5 \u03a9. During each experiment, key parameters were recorded at a sampling rate of 1 Hz throughout the entire discharge process. Prior to each test, the cell was fully charged to 4.2 V and subsequently discharged at a constant load until reaching a cutoff voltage of 2.5 V.The following parameters were monitored and recorded:DATE: Date and time of the experiment;VOLTAGE (V): Cell terminal voltage;CURRENT (A): Discharge current (negative values indicate discharge direction);POWER (W): Instantaneous discharge power;RESISTANCE (\u03a9): Equivalent discharge resistance;NTC_TEMP (\u00b0C): Surface temperature of the cell.The data acquisition system was developed using a Raspberry Pi 4 and an ADS1115 analog-to-digital converter, interfaced via the I\u00b2C protocol. Discharge current measurements were obtained using an ACS712 5 A Hall-effect sensor, while surface temperature was monitored using NTC 10 k\u03a9 thermistors."