The dV/dQ curve
dV/dQ curve is an analytical tool that can
analyze the loss of active lithium in lithium ion batteries. The peaks in the dV/dQ
curve mainly reflect the phase transition of the active substances in the
process of lithium immobilization and lithium removal.
dV/dQ curve mainly reflects the phase change
of positive and negative active substances in the charging and discharging
process. According to the data, we can find out the phase transition
corresponding to different characteristic peaks in the dV/dQ curve, and then
according to the variation trend of the dV/dQ curve in the cycle or in the
storage process, we can qualitatively infer the cause of the reversible
capacity loss of lithium ion battery, providing a reference for the design of
lithium ion battery.
The dQ/dV curve
The physical meaning of a dQ/dV curve is the
volume of a material per unit voltage. We all know that lithium ion batteries
have a voltage platform for both anode and cathode materials. A high negative
capacity on the voltage platform means that there is a lot of capacity in a
very small voltage fluctuation range, so it is a characteristic peak on the dQ/dV
curve. Usually we think of each peak on the dQ/dV curve as representing an
electrochemical reaction. Because the reaction potentials of different
materials are different, the positions and heights of peaks in the dQ/dV curve
will also be different.
How to operate in TOB cell tester system
1. dQ/dV curve setting
2. Select
the current display curve
3. View
the curve to see if achieved the desired effect
4. Click
the record-layer expand/collapse button
5. Data copy
6. Select the cycle range to copy