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When I tested OCV on a 100Ah LFP cell, I found that its SOC-OCV curve was non monotonic at 70% - 99% SOC. Is this a problem of cell production process?

I'm guessing that this is happening because the voltage change in the 60% to 90% SOC stage is too small (the voltage plateau is too flat), causing the effect of sensor error on the measurement results to be magnified?

I think this is the result of a complex electrochemical reaction inside the cell, and I will ask someone with in-depth research in this field, such as Dahn.

I charged and discharged the cells three times using a current of 20 A for capacity calibration. Then, the charge amount for each SOC interval was determined based on the calibrated capacity.This ensures that my SOC values are accurate. In addition, the interval is set to 1% for SOC within...

Since the sensor is installed inside the charging and discharging equipment, I do not know the model number of the sensor. However, I used a multimeter to compare the voltage measured at the positive and negative terminals of the battery with the measurement results of the charging and...

This is a square-case battery type cell (32mm*136mm*269.2mm), and both positive and negative posts are made of copper nickel-plated material. The power cord of the charger and discharger is connected to the poles using O-type terminals and nuts to complete the fastening.

But the data file sent to me by the manufacturer of the battery shows that the SOC-OCV curve they provided also appears similar to my own test results. Normally, the test environment and test results provided by the manufacturer are credible, right? So I wondered if this was due to this...

This doesn't make sense to you, you can choose not to click into this thread or choose not to reply. I just wanted to show a phenomenon that is strange and has bothered me.

Yes, I also think that this situation may be caused by the complex electrochemical reactions inside the battery. However, I cannot use the open circuit voltage method to determine the initial SOC value when the battery is in this voltage band. Even if there is no error in the voltage...

A strange situation occurred when I performed SOC-OCV testing on a LiFePO4 cell with a capacity of 105Ah using the incremental OCV method. The test uses a current multiplier of 0.2C, a resting time of 2h, an ambient temperature of 25°C, a charge cutoff voltage of 3.7V, a cutoff current of...