Test method for synchronously monitoring DCR change in secondary battery cycle process

Abstract

The invention belongs to the field of secondary battery cycle test, and particularly relates to a test method for synchronously monitoring DCR change in a secondary battery cycle process, which comprises the following steps: S1, installing a battery to be tested, and switching on a power supply; S2, carrying out constant-current discharging to a voltage U0 by using I1; S3, rotating the rotating shaft to reach a current I2 contact, and performing charging for t1 time with I2; recording the voltages U1 and U2 and the charging capacity C2; S4, rotating the rotating shaft to reach a current I3 contact, using I3 for charging, and the charging capacity is C3; S5, rotating the rotating shaft to reach a current I3 contact, and discharging for t2 time at I4; recording voltages U3 and U4 and a discharge capacity C4; S6, rotating the rotating shaft to reach a current I1 point, discharging at I1 to reach a voltage U0, and the discharging capacity is C5; S7, skipping to the step S2, and repeating for multiple times; the method is simple to operate, the DCR test is directly carried out in the cyclic test process, direct DCR data can be continuously obtained in the cyclic test process, and the cycle does not need to be suspended; DCR data is directly obtained through testing, and the precision is high; DCR data can be obtained in each cycle, and the test result is more detailed.

Description

technical field [0001] The invention belongs to the field of secondary battery cycle test, in particular to a test method for synchronously monitoring the change of DCR during the secondary battery cycle process. Background technique [0002] For secondary batteries including sodium-ion batteries and lithium-ion batteries, internal resistance testing is an important test. Internal resistance includes AC internal resistance IR and DC internal resistance DCR. AC internal resistance is to input an AC signal to the battery, and test the internal resistance measured by the voltage change generated by the signal. This method has a fast test speed; DC internal resistance is connected to the load at both ends of the battery, and the voltage is charged and discharged according to different currents. The voltage difference is divided by the current to calculate the internal resistance. The AC internal resistance of the battery is usually called ohmic internal resistance; the DC inte...

AI Technical Summary

Problems solved by technology

[0008] 1) Option 1, the operation is more troublesome, and the cycle must be suspended at a certain time; at the same time, it can only obtain DCR every certain number of weeks. Although the accuracy is high, it is still only available within the set cycle interval. Get DCR data once;

[0009] 2) Option 2, AC internal resistance and DC internal resistance are converted, which is not as accurate as the data obtained by direct testing

In addition, this method also needs to suspend the cycle to test the AC internal resistance during the cycle process, and the cycle process is still incoherent in the test;

[0010] 3) Option 3 is somewhat similar to Option 1. The disadvantage is that it can only compare the DCR at the initial stage of the cycle and the end of the cycle, and cannot monitor the DCR during the cycle.

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