Preparation method of lithium ion secondary battery

A secondary battery, lithium-ion technology, applied in the field of lithium-ion batteries, can solve the problems of poor charge and discharge performance of battery rate, poor high temperature storage performance, etc.

Active Publication Date: 2014-06-11
SHANGHAI BYD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The present invention aims to solve the problem that the SEI film prepared by battery formation in the prior art cannot have good lithium conductivity while having high electronic insulation, good thermal stability and chemical stability, resulting in poor rate charge and discharge performance of the battery. Or the technical problem of poor high-temperature storage performance, providing a preparation method of a lithium-ion secondary battery with excellent high-temperature stability and rate charge-discharge performance

Method used

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Examples

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preparation example Construction

[0011] The invention provides a method for preparing a lithium-ion secondary battery, the method comprising injecting a non-aqueous electrolyte into a battery casing equipped with a battery pole core, and then forming the battery injected with the non-aqueous electrolyte; wherein, The formation is carried out in three stages, the first stage is constant current and constant voltage charging with small current and low voltage, the second stage is small current constant current and constant voltage charging, and the third stage is constant current charging; Add additives to the non-aqueous electrolytic solution after the first stage ends, and before the third stage starts; the additives are at least one of water, hydrofluoric acid and fluoroethylene carbonate.

[0012] Generally speaking, the composition and formation system of the electrolyte closely affect the composition and composition of the SEI film. The solute, solvent and additives of the electrolyte all affect the perfo...

Embodiment 1

[0051] (1) Preparation of positive electrode

[0052] Lithium iron phosphate (LiFePO 4 ), and conductive carbon black (CB), polyvinylidene fluoride (PVDF), N-methylpyrrolidone (NMP) according to the weight ratio of LiFePO 4 : CB: PVDF: NMP = 100: 5: 3.5: 110 Prepare positive electrode slurry and stir at high speed for 2 hours to obtain positive electrode slurry. Double-sided dressing on aluminum foil with a thickness of 16um, spread evenly. Then dry at 120°C, roll, roll and cut into positive electrode sheets. The size of the electrode sheet is: length×width×thickness=471mm×42mm×140um, and the bulk density is 2.0g / cm 3 .

[0053] (2) Preparation of negative electrode

[0054] Graphite (C), conductive carbon black (Super P), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC) and deionized water by weight ratio C: Super P: SBR: CMC: H2O = 100:2 : 4: 2: 130 to prepare positive electrode slurry, stir evenly to prepare negative electrode slurry. Apply double-sided c...

Embodiment 2

[0061]The battery was prepared by the same method as in Example 1, except that the additive added was HF, and the amount of HF added was 25ppm. First, it was charged at a constant current of 0.005C to a cut-off of 1.6V, and then was charged at a constant voltage of 1.6V for 5 Hours; then charge with a constant current of 0.01C to a cut-off of 2.55V, then add additives and then constant voltage at a cut-off voltage of 2.55V for 2 hours; finally charge with a constant current of 0.1C to a cut-off of 3.7V. Battery S2 was produced.

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Abstract

The invention provides a preparation method of a lithium ion secondary battery. The method comprises the following steps of injecting non-aqueous electrolyte into a battery shell which is equipped with a battery pole shank, and forming the battery with the non-aqueous electrolyte, wherein the formation is divided into three steps, a first step is the constant-current constant-voltage charging in small current and low voltage, the second step is the constant-current constant-voltage charging of small current, and the third step is the constant-current charging; adding an additive into the non-aqueous electrolyte after the first step of the formation is ended and before the third step of the formation is started, wherein the additive is at least one of water, hydrofluoric acid and fluoro-ethylene carbonate. The battery prepared by utilizing the method is excellent in high-temperature stability and multiplying-power charging-discharging performance.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a preparation method of a lithium ion secondary battery. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, and no pollution. They have been widely used in mobile communications, notebook computers, power tools, and electric vehicles. These fields not only require high reversible capacity, long cycle / storage life, good safety, low cost, etc., but also require excellent rate charge and discharge performance and high and low temperature performance. [0003] The performance of lithium-ion batteries is closely related to its solid electrolyte interfacial film (SEI film). Excellent SEI film (dense, high lithium conductivity and electronic insulation, good thermal stability and chemical stability) can greatly improve the overall performance of the battery. [0004] Studi...

Claims

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Application Information

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IPC IPC(8): H01M10/058H01M10/0525
CPCY02E60/122H01M10/0525H01M10/058H01M10/4235H01M10/446Y02E60/10Y02P70/50
Inventor 沈晞沈益顺颜海鹏张欣欣张学全
Owner SHANGHAI BYD
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