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Lithium secondary battery and preparation method

A technology for batteries and battery casings, which is used in the manufacture of secondary batteries, electrolyte storage batteries, battery electrodes, etc., can solve the problems of poor low-temperature discharge performance, short cycle life, and low secondary battery capacity, and achieve good low-temperature discharge performance. , long cycle life, low temperature discharge performance and improved cycle performance

Active Publication Date: 2009-03-18
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the disadvantages of low capacity, poor low-temperature discharge performance and short cycle life of the prior art lithium secondary battery, and provide a lithium secondary battery with high battery capacity, good low-temperature discharge performance and long cycle life

Method used

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  • Lithium secondary battery and preparation method

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preparation example Construction

[0034] The preparation method of the negative electrode is the same as that of the positive electrode, except that the slurry containing the positive electrode active material, the binder and the conductive agent is replaced by the slurry of the negative electrode active material and the binder.

[0035] Various solvents and reagents described in the present invention are analytically pure.

Embodiment 1

[0038] This example illustrates the lithium secondary battery provided by the present invention and its preparation method.

[0039] (1) Preparation of positive electrode

[0040] Dissolve 30 grams of polyvinylidene fluoride (PVDF) in about 500 grams of N-methylpyrrolidone (NMP) solvent to prepare a binder solution, and then mix 940 grams of LiCoO 2 Add 30 grams of acetylene black powder as a conductive agent to the above solution, stir and mix well to obtain a positive electrode slurry; use a pulper to evenly coat the positive electrode slurry on both sides of an aluminum foil with a thickness of 18 microns, and make the coating The layer density is 23.5 mg / cm2. After heating and drying under vacuum at 125°C for 1 hour, roll forming by a twin-roller mill, and cutting into pieces to obtain a positive electrode of 360 mm (length) × 43.5 mm (width) × 130 microns (thickness), each positive electrode contains about 5.25 grams of LiCoO 2 .

[0041] (2) Preparation of negative el...

Embodiment 2-6

[0048] Examples illustrate the lithium secondary battery provided by the present invention and its preparation method.

[0049] Lithium secondary batteries were prepared according to the method of Example 1, except that the median particle diameter of the negative electrode active material was D 50 , the bulk density of the negative electrode material, the rolling conditions, the coating surface density of the negative electrode material and the coating surface density of the positive electrode material, as shown in Table 1 below.

[0050] Table 1

[0051]

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PUM

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Abstract

The lithium secondary battery includes battery container as well as pole set and non-aqueous electrolyte sealed inside the container. The pole set includes anode, cathode, and diaphragm located between anode and cathode. The anode includes current collection body of anode, and anode material painted on the body. The cathode includes current collection body of cathode, and cathode material painted on the body. The cathode material includes cathode active material and binding agent. Median size D50 of cathode active material is 12-20 micros. Volume density of cathode material is 1.50-1.65 g / cm3. Improving median size of cathode active material and volume density of cathode material raises capacity of lithium secondary battery based on current technical bases. The invention also improves discharge performance at low temperature, and prolongs cycle life.

Description

technical field [0001] The invention relates to a battery and a preparation method thereof, in particular, the invention relates to a non-aqueous electrolyte lithium secondary battery and a preparation method thereof. Background technique [0002] A lithium secondary battery refers to an ion battery composed of two compounds that can reversibly intercalate and deintercalate lithium ions as the positive and negative electrodes. Because of its high specific energy, high working voltage, wide working temperature range, low self-discharge rate, long cycle life, no pollution, light weight, good safety performance, etc., it has a wide range of applications. [0003] Lithium secondary battery generally comprises battery housing and the electrode group and the non-aqueous electrolytic solution that are sealed in this battery housing; Described electrode group comprises positive pole, negative pole and the separator between positive pole and negative pole; Described positive pole com...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/40H01M10/38H01M4/02H01M4/62H01M4/36H01M10/0525H01M10/058
CPCY02E60/122Y02E60/10Y02P70/50
Inventor 孙华军
Owner BYD CO LTD