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Method for analyzing impedance change trend of lithium ion battery in charging and discharging process

A charging and discharging process, lithium-ion battery technology, applied in the direction of measuring electrical variables, measuring electricity, measuring devices, etc., can solve the problem that the factors of impedance change are difficult to judge, and achieve the effect of simple operation method.

Inactive Publication Date: 2019-05-28
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] A method for analyzing the impedance change trend of a lithium-ion battery in the process of charging and discharging proposed by the present invention can solve the technical problem that it is difficult to judge the factors affecting the change of impedance of the lithium-ion battery in the process of charging and discharging

Method used

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  • Method for analyzing impedance change trend of lithium ion battery in charging and discharging process

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Experimental program
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Effect test

Embodiment 1

[0036] (1) According to the ratio of positive electrode active material: conductive agent: binder = 8:1:1, first weigh 16g of ternary positive electrode active material, then weigh 2g of SP, and mix the two in a mortar Grind for 30min. Then put it into an oven and bake for more than 5 hours.

[0037] (2) According to the ratio of PVDF:NMP=1:19, weigh 2gPVDF and 38gNMP in a beaker and stir on a magnetic stirrer until the PVDF is completely dissolved to form a bubble-free glue, and the time is more than 4h.

[0038] (3) Mix the powder in (1) with the glue in (2), stir in the mixing tank, adjust the mixing time, mixing speed, defoaming speed, and defoaming time to mix the powder and glue to form of slurry.

[0039] (4) Coat the above slurry on the coating machine, and divide it into two coating thicknesses, one is No. 1 312um, the other is No. 2 512um, and coat a uniform pole piece on the aluminum foil, and then Put it in an oven at 90°C and bake for about 30 minutes to dry th...

Embodiment 2

[0048] (1) According to the ratio of positive electrode active material: conductive agent: binder = 9.8:0.1:0.1, first weigh 19.6g of ternary positive electrode active material, then weigh 0.2g of SP, put the two in a mortar Mix and grind for 30 minutes. Then put it into an oven and bake for more than 5 hours.

[0049](2) According to the ratio of PVDF:NMP=1:19, weigh 0.2g PVDF and 3.8g NMP in a beaker and stir on a magnetic stirrer until the PVDF is completely dissolved to form a bubble-free glue, which takes more than 4 hours.

[0050] (3) Mix the powder in (1) with the glue in (2), stir in the mixing tank, adjust the mixing time, mixing speed, defoaming speed, and defoaming time to mix the powder and glue to form of slurry.

[0051] (4) Coat the above slurry on the coating machine, and divide it into two coating thicknesses, one is No. 1 254um, and the other is No. 2 418um. Coat a uniform pole piece on the aluminum foil, and then Put it in an oven at 90°C and bake for ab...

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Abstract

The invention provides a method for analyzing impedance change trend of a lithium ion battery in a charging and discharging process. The method can solve the technical problem that factors affecting the impedance change of the lithium ion battery in the charging and discharging process is difficult to judge. The method comprises the following steps that a positive electrode sheet is prepared according to a predetermined paste ratio and coating requirement; the areal density of the electrode sheet is measured and calculated; the electrode sheet is rolled, the thickness of the rolled electrode sheet is measured, and the compaction density of the electrode sheet is calculated; the rolled electrode sheet is baked and then assembled into a battery, and an electrolyte is injected; the impedanceof the battery is monitored in real time and recorded; the impedance change trend is analyzed according to the compaction densities of the electrode sheets, content of conductive agents in the electrode sheets and different electrolyte proportions in the batteries of different batches. The method for analyzing the impedance change trend of the lithium ion battery in the charging and discharging process has the advantages that the operation method is simple, the impedance change trends of a positive half-battery / negative half-battery / full battery / three-electrode battery can be analyzed, andthe method has certain guiding significance for analyzing and studying the impedance changes and battery failure causes in the batteries.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for analyzing the impedance variation trend of lithium-ion batteries during charging and discharging. Background technique [0002] During the charging and discharging process of lithium-ion batteries, the charge transfer impedance and SEI film impedance of the positive and negative electrodes will change continuously due to the deintercalation of lithium ions and the reaction between the electrolyte and the electrode material. In the previous work, the change of the positive and negative electrodes and the full battery impedance under different SOC (state of charge) was studied, and it was found that under low SOC, the impedance of the full battery and the positive electrode continued to decrease, and under high SOC, the impedance of the full battery and the positive electrode decreased continuously. Balanced with little to no fluctuation. Since the imped...

Claims

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Application Information

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IPC IPC(8): G01R31/389
Inventor 李丽娟吴欢欢杨刘倩
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY