Patent ID: 11959970
Assignee: BEIJING INSTITUTE OF TECHNOLOGY
Field: Measurement (Instruments)
Classification: CPC G  Y | IPC G

Claim 2:
3. A device for predicting capacity degradation of a lithium ion battery, comprising:
an acquisition module, configured to acquire an original battery discharge capacity;
a decomposition module, configured to decompose the original battery discharge capacity through a predetermined mode decomposition method to obtain battery discharge capacities composed of a plurality of different frequency signals, comprising:
decomposing an original battery discharge capacity S(t) through a CEEMDAN mode decomposition algorithm to obtain a battery discharge capacity composed of a plurality of high-frequency signals and a low-frequency signal, the battery discharge capacity being expressed as:

CEEMDAN(S(t))=Σi=1kdi(t)+rk(t)   (1)

in which k is a number of decomposed IMF components; di(t) is a high-frequency signal corresponding to the ith IMF component and rk(t) is a low-frequency signal corresponding to a residual signal;
a prediction module, configured to input the respective frequency signals into a pre-constructed capacity prediction model to obtain capacity prediction results corresponding to the respective frequency signals;
a screening module, configured to select a capacity prediction result that satisfies a predetermined relevance condition from the capacity prediction results corresponding to the respective frequency signals, comprising:
calculating a correlation coefficient between each frequency signal and the original battery discharge capacity respectively; selecting the frequency signal whose correlation coefficient is greater than or equal to a preset correlation threshold; and taking the capacity prediction result corresponding to the selected frequency signal as a capacity prediction result that satisfies the predetermined relevance condition, wherein the correlation coefficient is expressed as:, ρ
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in which pw is a correlation coefficient between a wth frequency signal and the original battery discharge capacity; dw(t) is a frequency signal corresponding to the wth IMF component; dw(t)is a mean of dw(t); S(t) is the original battery discharge capacity; S(t)is a mean of S(t); and n is a total battery charge-discharge cycle time; and
a reconstruction module, configured to reconstruct a predicted battery discharge capacity according to the capacity prediction result that satisfies the predetermined relevance condition,
comprising: reconstructing the predicted battery discharge capacity according to the capacity prediction result that satisfies the predetermined relevance condition and the capacity prediction result corresponding to the low-frequency signal, the battery discharge capacity being expressed as:

S′(t)=Σm=1Nd′m(t)+rk′(t)   (16)

in which S′(t) is the reconstructed battery discharge capacity, N is a number of capacity prediction results that satisfy the predetermined relevance condition, d′m(t) is the mth capacity prediction result that satisfies the predetermined relevance condition, and r′k(t) is the capacity prediction result corresponding to the low-frequency signal.