Preparation method of polymer lithium ion battery

A technology of lithium-ion batteries and polymers, applied in secondary batteries, circuits, electrical components, etc., can solve problems such as liquid leakage, uneven interface current distribution, and affecting battery safety performance, so as to improve cycle performance and safety performance, The effect of uniform distribution of interface current and smooth ion pathway

Inactive Publication Date: 2009-12-09
BYD CO LTD
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Problems solved by technology

The advantage of this method is that the polymer molecules interact with the electrolyte solvent molecules, and the electrolyte is adsorbed in the polymer film, so that there is no free liquid electrolyte in the entire battery, which can avoid safety problems such as leakage, but the disadvantage of this method In that: when the plasticizing temperature is higher than 60°C, the polymer film shrinks and closes pores, thereby blocking local ion pathways, causing uneven distribution of interfacial current and affecting the cycle performance and safety performance of the battery; and if the pressure treatment If the pressure is not properly controlled, the pole core will be pressed and the diaphragm will be pierced, resulting in an internal short circuit. At the same time, the micropores of the polymer film will be squeezed, which will reduce the ability of the polymer film to absorb electrolyte and cause leakage, which will affect the safety performance of the battery.

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  • Preparation method of polymer lithium ion battery

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preparation example Construction

[0020] The preparation method of the battery precursor is well known to those skilled in the art. For example, the method may include: preparing the positive electrode sheet and the negative electrode sheet of the battery; coating the polymer slurry on the surface of the positive electrode sheet and the negative electrode sheet to form a polymer film; disposing a separator between the positive electrode sheet and the negative electrode sheet to form a pole core ; The pole core is accommodated in the battery case, injected with electrolyte and packaged.

[0021] The polymer slurry contains polymer, solvent, plasticizer and inorganic filler; in the polymer slurry, the content of polymer, solvent, plasticizer and inorganic filler can be changed in a wide range, preferably Next, based on the total weight of the polymer slurry, the content of the polymer is 1-20% by weight, the content of the solvent is 50-90% by weight, and the content of the plasticizer is 1-20% by weight. 30% b...

Embodiment 1

[0044] This example is used to illustrate the preparation method of the polymer lithium ion battery provided by the present invention.

[0045] (1) Preparation of polymer lithium-ion battery precursor

[0046] 1) Preparation of positive electrode sheet

[0047] 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 electro...

Embodiment 2

[0061] This example is used to illustrate the preparation method of the polymer lithium ion battery provided by the present invention.

[0062] (1) Preparation of polymer lithium-ion battery precursor

[0063] 1) Preparation of positive electrode sheet

[0064] 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 electro...

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Abstract

The invention provides a preparation method of a polymer lithium ion battery, comprising the following step: plasticizing a precursor of the polymer lithium ion battery, wherein the plasticization comprises heating and the cooling the precursor of the battery, the temperature in a shell of the precursor of the battery is between 30 DEG C and 60 DEG C due to heating, the shell of the precursor of the battery is placed under the heating temperature for 0.1-10 hours, the temperature in the shell of the precursor of the battery is between 0 DEG C and 40 DEG C below zero due to cooling, and the shell of the precursor of the battery is placed under the cooling temperature for 0.1-10 hours. The preparation method achieves the better plasticizing effect of a polymer film by heating and cooling the precursor of the battery in the plasticizing process, thereby obviously enhancing the circulation performance and the safety performance of the obtained polymer lithium ion battery.

Description

technical field [0001] The present invention relates to a preparation method of a lithium ion battery, more specifically to a preparation method of a polymer lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high energy density, small size, no memory effect and long life. Battery. [0003] At present, lithium-ion batteries still use a liquid electrolyte system. Although lithium-ion batteries using a liquid electrolyte system have good high-rate charge-discharge performance and low-temperature performance, there are safety hazards such as leakage. [0004] Polymer lithium-ion batteries not only have the technical advantages of liquid lithium-ion batteries, but also have better safety performance due to no leakage. [0005] Polymer lithium-ion batteries mainly include a positive electrode sheet, a negative electrode sheet, a separator, a gel electrolyte layer between the positive electrode sheet and the sepa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/40H01M10/38H01M10/50
CPCY02E60/122Y02E60/10Y02P70/50
Inventor 潘福中单坤丁平尤胜萍
Owner BYD CO LTD
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