Detection method for microscopic lithium precipitation from cycles of lithium ion battery

Abstract

The invention discloses a detection method for microscopic lithium precipitation from cycles of a lithium ion battery. The detection method comprises the following steps: firstly, discharging a to-be-detected lithium ion battery; disassembling the lithium ion battery after discharging, taking out an anode piece and cleaning the anode piece to remove residual electrolyte; exposing the anode piece to the air for 5-20 h, performing heating and drying at 60-110 DEG C for 1-3 h, and converting precipitated lithium into lithium carbonate finally; measuring corresponding data by EDS (energy-dispersive X-ray spectroscopy) or chemical titration to determine the degree of lithium precipitation in the anode piece. Compared with the prior art, the method has the following advantages that the detectionrange is wide, the method is applicable to detection of microscopic lithium precipitation, and the degree of lithium precipitation can be judged visually based on specific data obtained by detection;detection convenience is higher, external interference of detection data is low, requirements of the detection method for equipment are low, and the detection cost is low; the method is applicable toanalysis of lithium precipitation from cycles of various lithium ion batteries such as LFP, NCM, LMO and the like.

Description

technical field [0001] The invention relates to the detection field of microscopic lithium analysis of lithium ion batteries, in particular to a detection method for lithium ion battery cycle microscopic analysis of lithium. Background technique [0002] In recent years, with the rapid development of portable electronic devices, electric vehicles, and grid energy storage technologies, the demand for high-energy-density, high-safety batteries and energy storage systems has become increasingly urgent. [0003] Lithium ionization during the cycle of lithium-ion batteries will cause capacity loss and cause safety problems. The attenuation of battery cycle capacity is mainly due to the loss of active lithium, which is mainly lost in the material, on the SEI film, or lithium ionization. Macroscopic lithium analysis can be observed with the naked eye; however, there are few detections of microscopic lithium analysis on the surface of negative electrode particles; in fact, the detec...

AI Technical Summary

Problems solved by technology

Macroscopic lithium analysis can be observed with the naked eye; however, there are few detections of microscopic lithium analysis on the surface of negative electrode particles; in fact, the detection results of microscopic lithium analysis usually have great guiding significance for the design of lithium battery related performance improvement

[0004] Chinese patent CN107728078 A discloses a detection method for lithium ion battery desorption in a lithium-ion battery. In the process of charging with a small current, constant current and constant voltage, if the voltage drops continuously at a certain stage, it is determined that the lithium-ion battery to be tested has a lithium-deposition phenomenon; On the one hand, the method is only a qualitative analysis and detection. It can only detect whether the lithium precipitation occurs in the battery, and cannot intuitively judge the degree of lithium precipitation through specific data; Voltage drop due to battery polarization

This method can quantitatively detect the negative electrode lithium precipitation of lithium-ion batteries, but it cannot rule out the interference effect on the test results caused by the inverse replacement reaction between lithium organic compounds on the SEI film and metal salt manganese ions, so the detection results are accurate. Disadvantages of low degree