Puncture-resistant and low-temperature-resistant cylindrical lithium ion battery and preparation method thereof

Abstract

A puncture-resistant and low-temperature-resistant cylindrical lithium ion battery comprises a positive plate, a negative plate, a diaphragm, an electrolyte and a cylindrical shell. The positive platecomprises positive slurry and an aluminum foil, and the aluminum foil is coated with the positive slurry. The positive slurry comprises the following components in percentage by weight: 68-70% of a positive solid substance and 30-32% of a solvent NMP. The positive solid substance comprises 94.5-95.5% of small-particle-size lithium cobalt oxide, 2.3-2.6% of a conductive agent SP, 0.5-0.7% of a conductive agent KS6 or conductive carbon black ECP and 1.7-2.2% of a polyvinylidene fluoride binder. The negative plate comprises negative slurry and a copper foil, and the copper foil is coated with the negative slurry. The negative slurry comprises the following components in percentage by weight: 50-53% of a negative solid substance and 47-50% of solvent water. The negative solid substance comprises 94.5-95.5% of negative graphite, 1.7-2.1% of a conductive agent SP, 1.4-1.7% of sodium carboxymethyl cellulose and 1.4-1.7% of an SBR binder. The lithium battery prepared by the preparation methoddisclosed by the invention not only can normally discharge at 2C and 3C at -40 DEG C, but also can pass a puncture performance test.

Description

technical field [0001] The invention relates to a puncture-resistant and low-temperature resistant cylindrical lithium-ion battery and a preparation method thereof, belonging to the technical field of lithium-ion batteries. Background technique [0002] With the process of economic globalization and the increasing demand for energy, the battery industry has developed rapidly. Lithium-ion batteries are currently the battery system with the best comprehensive performance. They have high specific energy, high cycle life, small size, light weight, and Memory effect, no pollution and other characteristics, are widely used in mobile phones, notebook computers, digital products, energy storage, electric vehicles, aerospace and other industries. [0003] With the wide application of lithium-ion batteries, due to their own chemical characteristics, on the one hand, the discharge of lithium-ion batteries will drop sharply at low temperatures, and the discharge current and discharge ti...

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Problems solved by technology

[0004] The discharge capacity of conventional cylindrical low-temperature lithium-ion batteries at 0.2C at -40°C can meet the discharge capacity of about 80%. Some cylindrical low-temperature lithium-ion batteries can also discharge at 2C and 3C rates at -40°C, but They all failed in the puncture performance test, and the battery caught fire and exploded in the test, especially for cylindrical lithium-ion batteries that meet the 2C and 3C rate discharge at -40°C, this defect is more obvious

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