Flexible package lithium ion battery silicon negative pole and manufacturing method thereof

A lithium-ion battery, ion battery technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problem of short battery cycle life, and achieve the effect of improving cycle stability and initial charge-discharge efficiency.

Active Publication Date: 2015-01-14

WANXIANG 123 CO LTD

9 Cites 21 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a soft-packed lithium-ion battery with high tensile capacity in order to solve the defect that the existing silicon-based negative electro...

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Abstract

The invention relates to a flexible package lithium ion battery silicon negative pole. The flexible package lithium ion battery silicon negative pole consists of a current collector and an active substance layer coating the surface of the current collector, wherein the active substance layer consists of the following substances in percentage by mass: 10-92 percent of silicon-carbon composite material, 2-70 percent of a conductive agent and 5-20 percent of an adhesive; the adhesive refers to polyimide; the porosity of the active substance layer is 30-65 percent, and the compaction density is 1.1-2.0g/cm<3>. Polyimide is dispersed by adopting a proper solvent, and the adhesive subjected to high-temperature polyacylation treatment has extremely high adhesive force, so that the prepared silicon negative pole piece has ultra-strong tension stress, the structure is kept stable in the repeated lithium-ion embedding and separating process, the first charge-discharge efficiency of the silicon negative pole can be obviously improved, and the cycling stability is improved.

Application Domain

Cell electrodesSecondary cells

Technology Topic

IonSolvent +14

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Examples

Experimental program(3)
Comparison scheme(1)
Effect test(1)

Example Embodiment

[0033] Example 1

[0034] A manufacturing method of a silicon negative electrode of a soft-pack lithium ion battery, the manufacturing method comprising the following steps:

[0035] a) Compounding: take the binder polyimide powder, add it to the organic solvent of nitrogen methyl pyrrolidone, prepare the glue with a solid content of 25%, and stir at a slow speed of 1000 rpm for 30 minutes;

[0036] b) Add conductive agent: add conductive agent super-p to the glue solution obtained in step a), and stir rapidly at 4000rpm for 1.5h to obtain conductive solution;

[0037] c) Add main material: Add silicon negative electrode material to the conductive liquid obtained in step b), stir at 800 rpm for 8 min, then quickly stir at 3000 rpm for 45 min, then add artificial graphite, after 8 min of slow stirring at 800 rpm, add NMP to adjust the solid content is 46%, rapidly stirred at 4000rpm for 1.5h, and then slowly stirred at 900rpm for 20min to obtain a slurry, wherein the mass ratio of silicon to artificial graphite is 1:1;

[0038] d) Sifting: passing the slurry obtained in step c) through a 100-mesh sieve, the solid content of the slurry is controlled at 40%; the viscosity is 1000 mPa.s;

[0039] e) Coating: Coat the slurry obtained in step d) on both sides of the aluminum foil, the thickness of the aluminum foil is 8 μm, the coating speed is 2 m/min, the air is blasted during coating, the wind speed is 5 m/s, and the porosity of the active material layer is is 30%, and the semi-finished product of the negative pole piece is obtained;

[0040] f) Drying: vacuum-drying the semi-finished negative pole piece obtained in step e) for 100 minutes, the temperature is 150°C, and the relative vacuum value of the vacuum-drying treatment is ≤-0.1MPa;

[0041] g) Rolling and punching: Rolling the semi-finished negative pole piece obtained in step f), compaction density: 1.1 g/cm 3 , after rolling, the negative pole piece is punched; among them, the silicon-carbon composite material is 90%, the conductive agent is 2% and the binder is 8%, and the coating density of the active material layer on the surface of the current collector is 50g/m2 2.

[0042]

Example Embodiment

[0043] Example 2

[0044] A manufacturing method of a silicon negative electrode of a soft-pack lithium ion battery, the manufacturing method comprising the following steps:

[0045] a) Compounding: take the binder polyimide powder and add it to the organic solvent composed of nitrogen methyl pyrrolidone and dimethylacetamide, and the volume ratio of nitrogen methyl pyrrolidone and dimethylacetamide is 1: 2. The solid content of the glue is adjusted to 5%, and the mixture is stirred at a slow speed of 800rpm for 40min;

[0046] b) Add conductive agent: add conductive agent super-p to the glue solution obtained in step a), stir rapidly at 3000 rpm for 2 hours, and obtain conductive liquid;

[0047] c) Add main material: Add silicon anode material to the conductive liquid obtained in step b), stir at a slow speed of 800rpm, after 10min, stir quickly at 3000rpm for 60min, then add hard carbon, stir at a slow speed of 800rpm for 10min, add NMP to adjust the solid state The content is 40%, rapidly stirred at 3500 rpm for 2 h, and then slowly stirred at 800 rpm for 30 min to obtain a slurry, wherein the mass ratio of the negative electrode material of silicon to hard carbon is 1:9;

[0048] d) Sifting: passing the slurry obtained in step c) through a 120-mesh sieve, the solid content of the slurry is controlled at 42%; the viscosity is 1500mPa.s;

[0049] e) Coating: Coat the slurry obtained in step d) on both sides of the aluminum foil, the thickness of the aluminum foil is 15 μm, the coating speed is 2.5 m/min, the air is blasted during coating, and the wind speed is 8 m/s, and the pores of the active material layer are The rate is 45%, and the semi-finished product of the negative pole piece is obtained;

[0050] f) Drying: vacuum-drying the semi-finished negative pole piece obtained in step e) for 110 minutes, the temperature is 200°C, and the relative vacuum value of the vacuum-drying treatment is ≤-0.1MPa;

[0051] g) Rolling and punching: Rolling the semi-finished negative pole piece obtained in step f), compaction density: 1.19g/cm 3 , after rolling, the negative pole piece is punched; among them, the silicon-carbon composite material is 10%, the conductive agent is 70% and the binder is 20%, and the coating density of the active material layer on the surface of the current collector is 100g/m2 2.

[0052]

Example Embodiment

[0053] Example 3

[0054] A manufacturing method of a silicon negative electrode of a soft-pack lithium ion battery, the manufacturing method comprising the following steps:

[0055] a) Compounding: take the binder polyimide powder and add it to an organic solvent composed of dimethylacetamide, nitrogen methyl pyrrolidone and dimethyl formamide, dimethyl acetamide, nitrogen methyl pyrrolidone The volume ratio to dimethylformamide is 1:2:1, the solid content of the glue is 15%, and the mixture is slowly stirred at 1000rpm for 50min;

[0056] b) Add conductive agent: add conductive agent super-p to the glue solution obtained in step a), and stir rapidly at 4000rpm for 2.5h to obtain conductive solution;

[0057] c) Add main material: Add silicon negative electrode material to the conductive liquid obtained in step b), stir at 800 rpm for 12 min, then quickly stir at 3000 rpm for 75 min, then add natural graphite, after 12 min of slow stirring at 800 rpm, add NMP to adjust the solid content is 60%, rapidly stirred at 4000rpm for 2.5h, and then slowly stirred at 900rpm for 40min to obtain a slurry, wherein the mass ratio of silicon to natural graphite is 1:5;

[0058] d) Sifting: passing the slurry obtained in step c) through a 140-mesh sieve, the solid content of the slurry is controlled at 45%; the viscosity is 2000mPa.s;

[0059] e) Coating: Coat the slurry obtained in step d) on both sides of the aluminum foil, the thickness of the aluminum foil is 25 μm, the coating speed is 3 m/min, the air is blasted during coating, the wind speed is 10 m/s, and the porosity of the active material layer is is 65%, and the semi-finished product of the negative pole piece is obtained;

[0060] f) Drying: vacuum-drying the semi-finished negative pole piece obtained in step e) for 140 minutes, the temperature is 350°C, and the relative vacuum value of the vacuum-drying treatment is ≤-0.1MPa;

[0061] g) Rolling and punching: Rolling the semi-finished negative pole piece obtained in step f), compaction density: 2 g/cm 3 , after rolling, the negative pole piece is punched; among them, the silicon-carbon composite material is 92%, the conductive agent is 3% and the binder is 5%, and the coating density of the active material layer on the surface of the current collector is 200g/m2 2.

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PUM

Property	Measurement	Unit
Compaction density	1.1 ~ 2.0	g/cm³
Thickness	8.0 ~ 25.0	µm
Compaction density	0.0 ~ 2.0	g/cm³
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Improve the first charge and discharge efficiency
Improve cycle stability

Flexible package lithium ion battery silicon negative pole and manufacturing method thereof

A lithium-ion battery, ion battery technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problem of short battery cycle life, and achieve the effect of improving cycle stability and initial charge-discharge efficiency.

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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