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About Stropower
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Solution
In-situ EIS Test Application for LiB
In-situ AC Impedance Characterization and Application Prospect of Charge and Discharge Test System
Background of In-situ EIS of Lithium-ion Battery
The EIS of lithium-ion battery is normally tested in electro-chemical equilibrium state with small enough excitation signals such as several mA of AC current, where the perturbation signal for measuring the response and impedance is neglectable for its distortion with the result; In comparison to EIS, the In-situ EIS is measured in the situation that all the conducting elements and mechanism are ongoing, i.e. during the process of charging or discharging, where the perturbation signal is still neglectable for its interference to the ECM (electronic circuit model) but the current or load profile is obviously drawing voltage drift and distorting the ECM - the voltage or SoC fluctuation or overpotential is making great difference to the measured result compared with equilibrium EIS (static EIS).
Fig. 1 EIS of Lithium-ion Battery and its frequency-dependance
Fig. 2 In-situ EIS versus EIS in different SoC% & Temperature
Application of In-situ EIS of Lithium-ion Battery
It is of great interest to researchers and industrial scientists that using the relationship between In-situ EIS (also called DEIS) to detect many microscale electro-chemical reactions and degradation mechanism through different good methods to measure the In-situ EIS for battery cells or the parallel or series modules. A lot of work has been done and published that proving the application of In-situ EIS is continuing to contribute new functions for engineering approach to intelligent management of LiBs either in vehicles or energy storage systems, such as online monitoring of battery temperature, process monitoring for battery production and EOL screening, cycling life estimation or pre-failure warning to lithium plating or thermal run-aways.
Fig. 3 Collective frequency related EIS & In-situ EIS application methodologies
STROPOWER EIS Measurement System
Stropower' EIS measurement system is industrial-leading solution for simulating the situation of current loading under different SoC | Temperature | SoH and measuring with exact perturbation sequencies in one unit - where the result is also online addressed. Giving great user flexibility of the test cases difference and saving a lot of efforts to users for repetitive cycling and data processing.
Fig. 4 Stropower EIS Measurement System offers all-in-one solution for EIS tests
Fig. 5 DEIS Measurement for aged battery cell - Rct can be linearly characterized with SoC and Current (both polarity)
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