Data from: "Battery state of health estimation using 1-minute post-charge relaxation: Robust to arbitrary cut-off voltages"

Introduction Dataset from the publication "Battery state of health estimation using 1-minute post-charge relaxation: Robust to arbitrary cut-off voltages", DOI: https://doi.org/10.1016/j.est.2026.121890. Sixteen commercial INR26650 lithium-ion batteries (nominal capacity: 5.3 Ah; operating voltage: 2.5–4.2 V) were cycled under two temperatures (25°C and 40 °C) and two charging protocols (CC and CC-CV). The CC charging/discharging currents are, respectively, 0.5 and 1 C-rates. The CV charging phase is terminated at a cutoff current of 0.1 C-rate. The battery capacity at each cycle is obtained based on the discharged capacity measured during a full CC discharge. Dataset Structure The dataset is divided into four subsets based on temperature and charging protocol. For simplicity, each subset is named using the format CYT-P. Here, T denotes the test temperature, and P indicates the charging protocols (e.g., CY25-CC denotes cells tested at 25 °C under CC charging without a CV phase). The four subsets are defined as follows: Dataset identifier Temperature Charging protocols Cell label CY25-CC 25 °C CC #1, #2, #3, #4 CY25-CCCV 25 °C CC-CV #5, #6, #7, #8 CY40-CC 40 °C CC #9, #10, #11, #12 CY40-CCCV 40 °C CC-CV #13, #14, #15, #16 Aging cycling procedure For each cycle, 30-minute relaxation data was collected at the charging cutoff voltage, which rotated sequentially among 3.8 V, 4.0 V and 4.2 V. Cycling procedure without CV charging as follows: Step Action Exit condition 1 CC charge at 0.5 C-rate 3.8 V reached 2 Rest 30 min limit reached 3 CC charge at 0.5 C-rate 4.2 V reached 4 CV charge Supplied current below 50 mA 5 Rest 5 min limit reached 6 CC discharge at 1 C-rate 2.5 V reached 7 Rest 5 min limit reached 8 CC charge at 0.5 C-rate 4.0 V reached 9 Rest 30 min limit reached 10 CC charge at 0.5 C-rate 4.2 V reached 11 CV charge Supplied current below 50 mA 12 Rest 5 min limit reached 13 CC discharge at 1 C-rate 2.5 V reached 14 Rest 5 min limit reached 15 CC charge at 0.5 C-rate 4.2 V reached 16 Rest 30 min limit reached 17 CC charge at 0.5 C-rate 4.2 V reached 18 CV charge Supplied current below 50 mA 19 Rest 5 min limit reached 20 CC discharge at 1 C-rate 2.5 V reached 21 Rest 5 min limit reached Cycling procedure with CV charging as follows: Step Action Exit condition 1 CC charge at 0.5 C-rate 3.8 V reached 2 CV charge Supplied current below 50 mA 3 Rest 30 min limit reached 4 CC charge at 0.5 C-rate 4.2 V reached 5 CV charge Supplied current below 50 mA 6 Rest 30 min limit reached 7 CC discharge at 1 C-rate 2.5 V reached 8 Rest 5 min limit reached 9 CC charge at 0.5 C-rate 4.0 V reached 10 CV charge Supplied current below 50 mA 11 Rest 30 min limit reached 12 CC charge at 0.5 C-rate 4.2 V reached 13 CV charge Supplied current below 50 mA 14 Rest 30 min limit reached 15 CC discharge at 1 C-rate 2.5 V reached 16 Rest 5 min limit reached Low C-rate test procedure For each operating condition, a designated cell (#4, #8, #12, or #16) underwent periodic low-rate characterization every 100 cycles, using a protocol designed to generate data for diagnosing degradation modes. This protocol consisted of a 0.05 C charge from 2.5 V to 4.2 V, followed by a 60-minute rest, and a 0.05 C discharge back to 2.5 V.