Method for identifying and pre-judging capacity diving fault of ternary battery

Abstract

The invention discloses a method for identifying and pre-judging a capacity diving fault of a ternary battery, and relates to the technical field of batteries. The method comprises the following steps: carrying out constant-power charging and discharging circulation on the ternary battery, recording a median voltage V of each circulation, and obtaining a curve of the median voltage V-circulation turns N of the battery and a slope a; presetting a slope protection threshold k, and identifying and pre-judging the capacity diving fault of the ternary battery, wherein if the slope a of the median voltage V-period N curve is less than k (the slope is negative), the battery capacity dives in the subsequent circulation process. The method particularly focuses on the non-full-charge and full-discharge process of the ternary battery, and in the process, as the capacity change of the battery in each cycle cannot be monitored, whether capacity diving occurs or not in the using process of the battery can be predicted as soon as possible by monitoring the change of the median voltage, so that the method can be better used in the full life cycle process of the battery.

Description

technical field [0001] The present invention relates to the field of battery technology, and more specifically, to a method for identifying and predicting a "diving" fault in the capacity of a ternary battery. Background technique [0002] In recent years, China's new energy vehicle market has developed rapidly. The annual output of new energy vehicles will exceed 2 million by 2020, and the cumulative production and sales will exceed 5 million. Ternary battery has the advantages of high energy density, long cycle life, low self-discharge efficiency, no memory effect, etc. main energy storage element. The installed capacity of ternary batteries in 2017 was 16.01GWh, accounting for about 43.94% of the total installed capacity. In 2018, the installed capacity was 33.09GWh, accounting for 58.17%. The proportion of installed capacity of ternary batteries has increased year by year, and has gradually become the mainstream power battery. [0003] However, in the later stage of th...

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Problems solved by technology

[0005] The present invention proposes a method for identifying and predicting the "diving" fault of the capacity of the ternary battery to solve the problem of how to predict the "diving" stage of the capacity of the ternary battery. It is characterized in that the method includes the following steps:

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