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Method for testing fast charging performance of negative electrode material

A technology of negative electrode material and testing method, which is applied in the field of testing the fast charging performance of negative electrode materials, can solve the problems of long testing period and complicated testing process of negative electrode materials, and achieve the effects of short testing time, efficient evaluation and simple data processing.

Active Publication Date: 2021-06-01
NINGBO SHANSHAN NEW MATERIAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a test method for the fast charge performance of negative electrode materials in order to overcome the defects of cumbersome test process and long test period of the fast charge performance of negative electrode materials in the prior art

Method used

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  • Method for testing fast charging performance of negative electrode material
  • Method for testing fast charging performance of negative electrode material
  • Method for testing fast charging performance of negative electrode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 5

[0052] The negative electrode material to be tested used in Example 5 is: the needle coke is pulverized, granulated, and graphitized in sequence to obtain carbon-free coated artificial graphite.

Embodiment 1

[0054] Negative electrode sheet production, 95.5wt% of the above-mentioned negative electrode material to be tested, 3%wt% of the binder and 1.5wt% of the conductive agent are mixed into a slurry, the viscosity is adjusted, and the copper foil is coated with a transfer coater. Lay out the pole piece, and then get the negative pole piece after rolling and cutting; according to the negative electrode shell→filler (shrapnel and gasket, the material of the shrapnel and the gasket is stainless steel, the specification of the shrapnel is 20mm*1.7mm, the gasket The specification is 20mm*0.4mm)→lithium sheet→electrolyte→diaphragm→electrolyte→negative pole piece→positive case, the battery is assembled in the order of which the amount of electrolyte added is 100μL, and the assembled battery is charged at a rate of 0.1C Discharge cycle for 2 weeks, and then discharge with a current rate of 3C. The obtained rate discharge curve is differentiated to obtain a differential curve with the SOC ...

Embodiment 1～5、 comparative example 1～3

[0060] The type of negative electrode material, the type of filler, the amount of electrolyte added, and the number of charge-discharge cycles are shown in Table 1 below, and the settings of other parameters are the same as in Example 1.

[0061] Such as figure 1 , figure 2 , image 3 , Figure 4 and Figure 5 Shown are respectively the 3C lithium analysis point graphs that embodiment 1~5 obtains. Such as Figure 6 , Figure 7 and Figure 8 Shown are the graphs of the 3C lithium precipitation points obtained in Comparative Examples 1 to 3, respectively. The graph of the lithium analysis point is obtained by differentiating the discharge curve.

[0062] It can be seen from the figure that the intersection point where the tangent of the platform on the curve intersects with the tangent of the "oblique line extending backward along the platform", and the corresponding SOC value in the abscissa is the lithium precipitation point. The results of lithium precipitation poin...

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Abstract

The invention discloses a method for testing the fast charging performance of a negative electrode material, and the method comprises the following steps of: sequentially performing charge-discharge cycle and discharge test on a half battery to obtain a discharge curve, differentiating the discharge curve to obtain a differential curve of which the abscissa is an SOC value and the ordinate is dV / dQ, adopting an intersection point of a tangent line of the platform in the differential curve and a tangent line of an oblique line extending backwards along the platform is a lithium precipitation point; the half battery comprises a negative pole piece, filler, an electrolyte solution, a lithium sheet and a diaphragm, and the negative pole piece contains a to-be-detected negative pole material; the filler contains a gasket; the addition amount of the electrolyte solution is more than 30 microliters and less than 200 microliters; the number of charge-discharge cycle is two or more; the multiplying power of the charge-discharge cycle is 0.05-0.5C; and the rate of discharge test is 1-5C. The test method is short in test time, simple in data processing, and efficient and accurate in detection of evaluating the fast charging performance of the negative electrode material.

Description

technical field [0001] The invention relates to a method for testing the fast charging performance of negative electrode materials. Background technique [0002] The development of electric vehicles depends on technological improvements to lithium-ion batteries. In addition to increased capacity and power, consumers are demanding shorter charging times. However, current commercial batteries do not meet fast charging currents, especially at sub-ambient temperatures, and the result is lithium metal deposition on the surface of the negative electrode, known as a lithium-leaching layer. Partial or full deposition of Li metal occurs on the anode surface, rather than the transported Li being fully intercalated in the anode, lithium desorption in the battery is accompanied by severe Li ion and capacity loss due to the formation of additional SEI on the additional Li surface and the growth of It is caused by the loss of electrical contact during Li dendrite relaxation. These dend...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/385G01R31/378
CPCG01R31/385G01R31/378Y02E60/10
Inventor 刘晶孙宝利陈明樊少林崔贝磊吴敏昌
Owner NINGBO SHANSHAN NEW MATERIAL TECH