I have been testing Li-ion pouch cells at low temperature in the potential window of 2.8-4.1 V. I found that the pouch cell starts its charging from 3.2 V (instead of 2.8 V) and discharging from 3.9 V (instead of 4.1 V). I was wondering what could be the exact reason for this voltage drop.
PS. all charging and discharging are done at same low temperature
It would not be superfluous to recall that the potential of a cell under current is equal to the sum of the equilibrium potential and the charge / discharge overvoltage. Overvoltage depends on the internal resistance of the cell. One of the main contributions to the internal resistance of cell is the resistance of the electrolyte, which is strongly dependent on temperature. In addition, the equilibrium potential of the cell also depends on temperature. So no wonder. On the contrary, if the potential of cell did not depend on the temperature, it would be very strange.
It would not be superfluous to recall that the potential of a cell under current is equal to the sum of the equilibrium potential and the charge / discharge overvoltage. Overvoltage depends on the internal resistance of the cell. One of the main contributions to the internal resistance of cell is the resistance of the electrolyte, which is strongly dependent on temperature. In addition, the equilibrium potential of the cell also depends on temperature. So no wonder. On the contrary, if the potential of cell did not depend on the temperature, it would be very strange.
SALAM ALAIKUM
THE QUANTITY THERMAL IS INFLUENCE ON ACQUIRED ENERGY OF IONS AT TRANSMISSION. THEREFORE, WHERE HAS BEEN THERE HIGH ENERGY, THE ION WILL HAVING HIGH TRANSMISSION ENERGY. MOREOVER, THE REACTANCE OF BATTERIES WILL DECREASING
Dear Vadim S. Gorshkov , Mustafa Alqadoori , thank you very much for your inputs. As i have known that the increase of internal resistance at low temperature can influence the voltage window, i am looking for the answers in terms of electrochemistry.
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