A non-destructive analysis method for judging whether lithium precipitation occurs in a battery during cycling

Abstract

The invention discloses a non-destructive analysis method for judging whether lithium precipitation occurs in a battery during the cycle process, comprising: step S1, according to the charging system adopted by the cycled battery to be tested, to obtain the characteristic charging current I t and the characteristic charging current I t Under the corresponding characteristic cut-off voltage V t ; Step S2, obtain the cycled battery at the characteristic charging current I t The threshold voltage V at which lithium precipitation begins to occur during constant current charging Lm ; Step S3, obtain the fresh battery at the characteristic charging current I t The threshold voltage V at which lithium precipitation begins to occur during constant current charging L0 ; Step S4, based on the cycled battery threshold voltage V Lmn Threshold voltage V L0 The relationship between them is used to analyze and judge the possibility of lithium precipitation and subsequent lithium precipitation in the cycled battery. The present invention can realize the judgment of whether the battery undergoes lithium deposition and the possibility of subsequent lithium deposition in the cycle process.

Description

technical field [0001] The invention relates to the technical field of performance detection and analysis of lithium-ion batteries, in particular to a non-destructive analysis method for judging whether lithium precipitation occurs in a battery during a cycle. Background technique [0002] With the advancement of technology, lithium-ion batteries are widely used in the fields of consumer electronics, energy storage and electric vehicles due to their significant advantages such as high energy density, long cycle life, green and pollution-free. In the performance evaluation of lithium-ion batteries, an essential technical indicator is cycle life, including cycle life at various temperatures and even some extreme application environments. [0003] In the cycle test, in addition to paying attention to the capacity retention rate of the battery, whether and when lithium deposition occurs during the cycle is also an important life evaluation index. As we all know, once lithium de...

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Problems solved by technology

As we all know, once lithium deposition occurs in the battery, it will not only accelerate the performance decline, but also easily form dendrites with the accumulation of lithium deposition, which will easily cause short circuit in the battery and cause safety hazards

[0004] At present, it is generally adopted to dissect the battery after a certain number of cycles, and judge whether lithium precipitation occurs during the battery cycle by observing the state of the negative plate with the naked eye of the staff. This method requires the production of multiple batteries at the same time. Cycle test, It is a destructive analysis method, which not only wastes test resources, but also has strong subjectivity by naked eye observation, and a small amount of lithium analysis may not be easily detected

[0005] In addition, the above-mentioned existing analysis methods require anatomical observation of the battery after a certain number of cycles. This method can only lock the occurrence of lithium deposition in the battery within a certain cycle stage range, but cannot accurately determine when the battery begins to undergo lithium deposition. Corresponding number of cycles

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