A lithium ion battery

A technology of lithium-ion batteries and separators, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of increased battery thickness, damage to electronic devices, and influence on normal operation, etc., to reduce calorific value and improve Effects of safety performance and long cycle life

Active Publication Date: 2015-11-25
DONGGUAN AMPEREX TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] During the charge and discharge process of lithium-ion batteries, Li+ is extracted and intercalated in the positive and negative active material particles. This deintercalation process causes changes in the lattice volume of the active material, such as: for the positive active material, LiCoO 2 , the lithium-ion battery whose negative electrode active material is graphite, during the charging process of the battery, Li+ from LiCoO 2 out of the particles and embedded in the graphite particles, this process will cause the LiCoO 2 And the increase in the volume of graphite particles is reflected in the increase in the thickness of the pole piece macroscopically. If there is no room for release in the battery, it will lead to an increase in the overall thickness of the battery.
Due to the limitation of the design size of portable electronic equipment, there are strict requirements on the dimensional stability of the battery. The increase of battery thickness may damage the electronic devices in the portable equipment and affect its normal operation.

Method used

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  • A lithium ion battery
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Examples

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preparation example Construction

[0035] 1. Preparation of positive electrode sheet

[0036] The structure and composition of the positive electrode sheet: the positive electrode sheet includes a positive electrode current collector and a positive electrode diaphragm attached to both sides of the current collector. The positive electrode diaphragm includes a positive electrode active material, a binder, and a conductive agent. The present invention has no special limitation on the positive electrode active material. Existing positive electrode active materials for lithium ion batteries such as: LiCoO2, LiNiO2, LiMn2O4, LiNiMnCoO2, LiFePO4, etc. can be used to prepare the lithium ion battery disclosed by the present invention. The bonding agent and the conductive agent are not particularly limited, and the present invention can use all the positive current collectors, adhesives, and conductive agents that can be used in existing lithium-ion batteries. Considering the degree of maturity of the process, the prese...

Embodiment 1

[0050] Preparation of the negative electrode sheet: mix the negative electrode active material graphite, the thickener sodium carboxymethyl cellulose (CMC), the conductive agent (Super-P) and the binder styrene-butadiene rubber emulsion (SBR) with deionized water to obtain Negative slurry. The negative electrode slurry was evenly coated on a copper foil with a thickness of 9 μm by a coating process, and the negative electrode sheet was obtained after drying, rolling and slitting.

[0051] Preparation of positive electrode sheet: uniformly mix LiCoO2 powder, binder polyvinylidene fluoride, conductive agent (Super-P) and N-methylpyrrolidone to obtain positive electrode slurry. The positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 14 μm by a coating process, and the positive electrode sheet was obtained after drying, rolling, and slitting.

[0052] Liquid electrolyte: the organic solvent and its weight ratio are EC / PC / EMC=1:1:1, the lithium s...

Embodiment 2

[0056] Except for using a separator made of PE, with a porosity pr of 65%, and a thickness d of 14 μm, the others are the same as in Embodiment 1.

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Abstract

The invention discloses a lithium ion battery. A liquid electrolyte is filled in apertures of positive and negative pole active material layers of the lithium ion battery. A gel state electrolyte is filled in apertures of a separation film. The porosity pr of the separation film is great than or equal to 50% and is less than or equal to 78%. The elastic modulus of the gel state electrolyte is greater than that of a common separation film material. When pole pieces swell in lithium ion battery charging, the gel state electrolyte is easy to be compressed so that a space needed by pole piece thickness increase is obtained, and thus thickness increase of the whole lithium ion battery is reduced in lithium ion battery charging. In addition, the lithium ion battery provided by the invention has good short circuit safety and good electrochemical properties.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery with good dimensional stability during charge and discharge cycles. Background technique [0002] Due to the rapid development of electronic technology and communication technology, portable electronic and communication devices such as smart phones, notebook computers, tablet computers, e-books, digital cameras, etc. have been widely used. Due to the increasing functions and miniaturization of these portable devices, batteries with high energy density and long service life are required to provide power support for them. Lithium-ion batteries have the characteristics of environmental protection, high energy density, and long cycle life, and have broad application prospects in portable electronic and communication equipment. [0003] During the charge and discharge process of lithium-ion batteries, Li+ is extracted and intercalated in the positive and neg...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0525H01M2/18H01M10/056
CPCY02E60/122Y02E60/10
Inventor 闫晓红
Owner DONGGUAN AMPEREX TECH
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