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Method for making lithium ion battery diaphragm by ion template effect

A lithium-ion battery and stencil technology, which is applied to battery components, circuits, electrical components, etc., can solve the problem of difficult control of film pore size, pore size distribution and porosity, affecting battery discharge capacity and cycle life, lithium ion transmission Uneven speed and other problems, to achieve the effect of extended cycle life, stable discharge capacity, and uniform porosity

Inactive Publication Date: 2013-11-06
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical defects of the above two methods are: in the process of oriented stretching of the film, the pore size, pore size distribution and porosity of the film are difficult to control uniformly, resulting in the transfer of lithium ions between the positive and negative electrodes during the electrochemical charge and discharge process in the battery. The uneven speed and quantitative transmission of lithium ions are seriously affected, which directly affects the discharge capacity and cycle life of the battery

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] 184 grams of biphenyldiamine and 218 grams of pyromellitic anhydride, 2278 grams of N,N-dimethylacetamide were heated to 70°C for 5 hours in the reactor, and 67 grams of lithium carbonate were added to the reactor, stirred for 2 hours; the reaction product is cast into a film, and the film is removed at 80°C to remove N,N-dimethylacetamide; then the film is heated to 150°C for decarboxylation and dehydration to make a polyimide film containing lithium oxide, the thickness of the film is 30 μm. The film is repeatedly extracted with dilute hydrochloric acid aqueous solution to remove lithium oxide, the film is dried and cut into finished products.

Embodiment 2

[0021] 184 grams of biphenyldiamine and 294 grams of biphenyltetracarboxylic anhydride, 4302 grams of N,N-dimethylacetamide were heated to 80°C for 5 hours in the reactor, and 67 grams of lithium carbonate were added to the reactor, stirred for 2 hours; the reaction product is cast into a film, and the film is removed at 70°C to remove N,N-dimethylacetamide; then the film is heated to 170°C for decarboxylation and dehydration to make a polyimide film containing lithium oxide, the thickness of the film is 50 μm. The film is repeatedly extracted with dilute hydrochloric acid aqueous solution to remove lithium oxide, the film is dried and cut into finished products.

example 3

[0023] 184 grams of biphenyldiamine and 310 grams of biphenyltetracarboxylic acid ether anhydride, 4446 grams of N, N-dimethylacetamide in the reactor rises to 90 ° C for 5 hours, add 67 grams of lithium carbonate in the reactor, stir 2 hours; the reaction product was cast into a film, and the film was removed at 90°C to remove N,N-dimethylacetamide; then the film was heated to 190°C for decarboxylation and dehydration to make a polyimide film containing lithium oxide. The thickness is 85 μm. The film is repeatedly extracted with dilute hydrochloric acid aqueous solution to remove lithium oxide, the film is dried and cut into finished products.

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PUM

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Abstract

The invention relates to a lithium ion battery technology and aims at providing a method for making a lithium ion battery diaphragm by ion template effect. The method comprises the following steps of: adding lithium carbonate with the same molar with benzidine after reacting the benzidine, aromatic anhydride and N, N-dimethyl acetyl amide, and then agitating until uniformly mixing for reaction; after casting the mixture into a film, removing residual N, N-dimethyl acetyl amide, and then heating the film for decarboxylation and dehydration to make a polyimide film containing lithium oxide; repeatedly extracting with a thin hydrate solution to remove the lithium oxide, and obtaining the porous polyimide film with uniform lithium ion bore diameters. The invention has the advantages that the bore diameters of the film can be effectively controlled in the diameter range of lithium ions, the bore diameter distribution and the bore clearance rate are uniform, uniform transmission speed of the lithium ions between a positive electrode and a negative electrode and quantitive lithium ion transmission are ensured in the electrochemical charge and discharge process of the battery, the discharge capacity of the battery is stable, and the cycle service life is prolonged.

Description

technical field [0001] The invention relates to lithium-ion battery technology, in particular to a method for preparing a lithium-ion battery diaphragm by utilizing ion template effect. Background technique [0002] Since Sony successfully developed lithium-ion batteries in the early 1990s, lithium-ion batteries have developed rapidly due to their excellent electrical properties such as high energy density, long cycle life, and high voltage. At present, it has been widely used in the fields of electronic products such as mobile phones, portable computers, cameras, and video cameras, and the application fields are still expanding. Lithium-ion batteries consist of positive and negative electrodes, electrolytes and separators. Among them, an important function of the separator is to isolate the positive and negative electrodes and prevent the passage of electrons in the battery, while allowing the passage of ions, thereby completing the rapid transmission of lithium ions betwe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14
CPCY02E60/12Y02E60/10
Inventor 孙维林孙启杭孙卓彦
Owner ZHEJIANG UNIV