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Formation method for lithium ion secondary battery

A secondary battery and chemical formation method technology, applied in secondary batteries, electrochemical generators, non-aqueous electrolyte storage batteries, etc., can solve the problems of poor cycle performance and overcharge performance of lithium-ion secondary batteries, and achieve improved cycle performance and overcharge performance, the effect of overcoming performance defects

Inactive Publication Date: 2008-12-03
SHANGHAI BYD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to overcome the disadvantages of poor cycle performance and overcharge performance of lithium-ion secondary batteries obtained by existing chemical formation methods, and provide a method for forming lithium-ion secondary batteries that enable batteries to have good cycle performance and overcharge performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] This example illustrates the preparation of a lithium ion secondary battery.

[0035] (1) Preparation of positive electrode

[0036] 100 g of the positive active ingredient LiCoO 2 1. Mix 2 grams of binder polyvinylidene fluoride (PVDF), 3 grams of conductive agent acetylene black with 40 grams of N-methylpyrrolidone, and then stir in a vacuum mixer to form a uniform positive electrode slurry.

[0037] The slurry was evenly coated on an aluminum foil, then dried at 150°C, rolled, and cut to obtain a positive electrode with a size of 540×43.5 mm, which contained 5.8 grams of active ingredient LiCoO 2 .

[0038] (2) Preparation of negative electrode

[0039] Mix 100 grams of natural graphite, a negative electrode active ingredient, 1 gram of binder polyvinylidene fluoride (PVDF), and 40 grams of N-methylpyrrolidone, and then stir in a vacuum mixer to form a uniform negative electrode slurry.

[0040] The slurry was uniformly coated on a copper foil, then dried at 90° ...

Embodiment 2

[0044] This embodiment illustrates the formation method of the lithium ion secondary battery provided by the present invention

[0045] At 25°C, first charge the battery containing 2.5 grams of electrolyte A prepared in Example 1 to 3.5 volts at a current of 0.05C, and then inject 1.0 grams of electrolyte B into the battery again. B is the LiPF 6 Dissolve in the mixed solvent of chain ester EC, DEC and EMC and overcharge additive biphenyl by the concentration of 0.9 mol / liter to form non-aqueous electrolyte B, the mixed solvent of described chain ester EC, DEC and EMC and The weight ratio of biphenyl is 32:1; the volume ratio of EC, DEC and EMC is 2:1:3. After injecting the electrolyte solution B, the battery was continuously charged at 25° C. with a constant current of 0.1 C to 3.8 volts to complete the formation, and the liquid injection hole was sealed to obtain the formed lithium-ion battery A1.

Embodiment 3

[0047] This embodiment illustrates the formation method of the lithium ion secondary battery provided by the present invention

[0048] Then, according to the method of Example 2, the battery containing 2.5 grams of electrolyte A prepared in Example 1 was formed. The current was charged to 3.8 volts at a constant current, and then the battery was placed at 25°C for 24 hours to complete the formation, and the liquid injection hole was sealed to obtain the formed lithium-ion battery A2.

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Abstract

The invention provides a formation method used for a lithium ion secondary battery. The method comprises the following steps that: electrolyte is injected into the lithium ion secondary battery and then aged; subsequently, the lithium ion secondary battery is charged; the charging method comprises a first charging process and a second charging process; after the first charging process is completed, the electrolyte is injected into the lithium ion secondary battery again; the injected electrolyte before the first charging process and the electrolyte which is injected into the lithium ion secondary battery after the first charging process respectively and independently are mixed solution which contains the electrolyte lithium salt and the chain-shaped acid ester; wherein, the electrolyte injected into the lithium ion secondary battery before the first charging process also contains film-forming additive; the electrolyte which is injected into the lithium ion secondary battery again after the first charging process also contains overcharging additive. The formation method of the lithium ion secondary battery of the invention can effectively improve the comprehensive electrochemical performance of the battery.

Description

technical field [0001] The invention relates to a method for forming a battery, in particular, the invention relates to a method for forming a lithium ion secondary battery. Background technique [0002] The formation step of lithium-ion rechargeable batteries is an important stage in the manufacture of batteries. The formation is related to the quality of the battery's capacity, cycle life, and safety performance. Formation is the process of charging a battery for the first time. There are mainly two ways of formation of the existing lithium-ion secondary batteries, sealed formation and open formation. The sealing formation is to seal the liquid injection hole after the electrolyte is injected, and then perform the battery formation, and at the same time form the SEI film (Solid Electrolyte Interface) on the surface of the negative electrode through the electrochemical reaction during charging. However, some gases, such as hydrogen fluoride, carbon monoxide, carbon dioxid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/38H01M10/058
CPCY02E60/10Y02P70/50
Inventor 魏岩巍张静王晓普
Owner SHANGHAI BYD
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