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A kind of lithium battery and preparation method thereof

A lithium battery and electrolyte technology, applied in the field of lithium battery and its preparation, can solve the problems of insufficient performance such as low conductivity theoretical specific capacity, energy efficiency ratio, energy density, etc., to improve energy efficiency ratio, improve charge-discharge efficiency and cycle performance, the effect of avoiding oxidation

Active Publication Date: 2019-12-03
江苏海四达电源有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, limited by the low electrical conductivity of the material itself and the theoretical specific capacity of 170mAh / g, it is slightly insufficient in terms of energy efficiency ratio and energy density.

Method used

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  • A kind of lithium battery and preparation method thereof
  • A kind of lithium battery and preparation method thereof
  • A kind of lithium battery and preparation method thereof

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preparation example Construction

[0045] The present invention also provides a preparation method of a lithium battery, comprising the following steps:

[0046] (1) Preparation of positive electrode;

[0047] (2) preparation of negative electrode;

[0048] (3) After winding the positive electrode, negative electrode and separator, inject the electrolyte, then fill the lithium battery with an inert gas until the pressure is 0.3-3MPa, then stand the lithium battery at 20-35°C for 6-24h, and then Stand upright at 40-55°C for 6-24h, then vacuumize to a pressure of -0.08-0.05MPa and seal to obtain a lithium battery.

[0049] According to the present invention, in the preparation of the battery, during the infiltration process of the electrolyte, the pressure inside the battery is increased by injecting an inert gas so that the electrode sheet can be completely infiltrated by the electrolyte, thereby increasing the ion and electron density in the later charging and discharging process. Transmission efficiency, imp...

Embodiment 1

[0069] (1) Positive electrode preparation

[0070] 1.6kg PVDF was dissolved in 21kg NMP to obtain a PVDF glue solution with a mass concentration of 7%; 96.8kg carbon-coated lithium iron phosphate (volume average particle size distribution D50 was 10 μm, tap density 1.2g / cm 3 , The specific surface area is 15m 2 / g), 1kg conductive graphite, 0.6kg graphene and the above-mentioned PVDF glue were stirred evenly under the condition of 40°C vacuum degree≤-0.08MPa to prepare positive electrode slurry;

[0071] Coat the positive electrode slurry on the front and back sides of a graphene-coated aluminum foil with a thickness of 20 μm (graphene layer is 2 μm + aluminum foil with a thickness of 16 μm), then dry at 120 ° C, roll under a pressure of 1.6 MPa and then cut Slitting on the machine to obtain a positive electrode with a size of 2350mm×180mm×20μm, and an area density of 161g / m 2 , the compacted density is 2.3g / cm 3 positive pole.

[0072] (2) Negative electrode preparation ...

Embodiment 2

[0078] (1) Positive electrode preparation

[0079] 1.5kg PVDF was dissolved in 28.5kgNMP to obtain a PVDF glue solution with a mass concentration of 5%; 96.5kg carbon-coated lithium iron phosphate (volume average particle size distribution D50 was 12 μm, tap density 1g / cm 3 , the specific surface area is 10m 2 / g), 1kg conductive graphite, 1kg graphene and the above-mentioned PVDF glue were stirred evenly under the condition of 40°C vacuum degree≤-0.08MPa to prepare positive electrode slurry;

[0080] Coat the positive electrode slurry on the front and back sides of a graphene-coated aluminum foil with a thickness of 18 μm (graphene layer is 2 μm + aluminum foil with a thickness of 14 μm), then dry at 120 ° C, roll under a pressure of 1.6 MPa and then cut Slitting on the machine to obtain a positive electrode with a size of 5300mm×74mm×20μm, and an area density of 155g / m 2 , the compacted density is 2.4g / cm 3 positive pole.

[0081] (2) Negative electrode preparation

[0...

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Abstract

The invention relates to the technical field of lithium batteries, in particular to a lithium battery and a preparation method thereof. The lithium battery includes a positive electrode, a negative electrode, a separator and an electrolyte, and the positive electrode includes a positive electrode current collector and is coated on the positive electrode current collector. The positive electrode material on the surface, wherein the positive electrode current collector is a graphene-coated aluminum foil; the negative electrode includes a negative electrode current collector and a negative electrode material coated on the negative electrode current collector, wherein the negative electrode current collector is coated with graphite vinyl layer copper foil. The present invention uses graphene-coated aluminum foil and graphene-coated copper foil as the positive current collector and the negative current collector respectively, which not only improves the conductivity of the positive current collector and the negative current collector, but the graphene coating can also avoid metal oxidation, Thereby improving the charging and discharging efficiency and cycle performance of the lithium battery.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a lithium battery and a preparation method thereof. Background technique [0002] After years of development, lithium-ion batteries have become the most widely used power source for new energy vehicles, and are widely used in the field of electric vehicles, such as hybrid buses and pure electric buses. In the process of using lithium-ion batteries, the charging and discharging efficiency is the key point of energy utilization and has attracted much attention, and it is also one of the important issues currently being studied by technicians. Internal resistance is one of the key factors affecting charge-discharge efficiency and cycle life. Large internal resistance will cause the specific energy of the battery to drop significantly at high power output, thereby deteriorating the starting performance; increasing the temperature of the battery, threatening the safety; and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0587H01M4/66H01M10/052
CPCH01M4/663H01M10/052H01M10/0587Y02E60/10Y02P70/50
Inventor 沈晓彦杜亚辉沙永香王兴威李云扬胡丹丹
Owner 江苏海四达电源有限公司