Department of Energy and Environment Division of Electric Power Engineering Lithium-ion batteries have taken quite a leap in the worldwide market and are one of the most important electric components whether it is in an. EIS – Electrochemical Impedance Spectroscopy SOC – State of Charge OCV – Open Circuit Voltage CPE – Constant Phase Element. The purpose of this thesis is to test and compare different methods such as pulse tests and EIS with focus in the low frequency area and.
Due to the pulse test condition, the discharge process is required, and the battery needs to be guaranteed to have a certain amount of power. The ideal voltage stage of the pulse test is around 3.4 V (S2) to reach high accuracy of capacity estimation.
Can a pulse test improve battery capacity estimation?
The combined data-driven methods and pulse tests could achieve an average of over 95% accuracy of capacity estimation. Therefore, our efficient and innovative new pulse test integrated with the data-driven algorithm could open up a new window for fast estimation of the remaining battery capacity.
Interestingly, the proposed pulse test strategy for battery capacity measurement could reduce test time by more than 80% compared with regular long charge/discharge tests. The short-term features of the current pulse test were selected for an optimal training process.
How accurate are pulse tests for lithium ion batteries?
Such pulse tests last for only a few seconds and are convenient to perform in various working conditions of the LIBs. This unique proposed method could reach an overall accuracy of 95% for remaining capacity estimation even for batteries with less than 50% SOH.
How effective is a pulse test for Battery polarization?
Our research also shows that the effectiveness of the model majorly depends on the pulse test, which can reflect the battery's internal resistance as the polarization deepens with the development of aging. Secondly, it is necessary to unify the battery to the same state before the pulse test.
What is a pulse test?
The pulse tests were done from 90-10% SOC with 40 pulses of 30A with the length of 20 seconds at each SOC point, an example of a pulse can be seen in figure 14 with a length of 120 seconds. For this measurement, the battery cell was charged to 100% SOC and then discharged 10-20% depending on SOC level for each measurement.