A cylindrical lithium-ion battery

A technology of lithium-ion batteries and cylinders, which is applied to battery electrodes, secondary batteries, battery pack components, etc., can solve problems such as serious low-temperature rate problems, complicated production processes, and unfriendly environments, and achieve improved electrochemical performance and cost-effectiveness. Effect of low film resistance and optimized coating surface density

Active Publication Date: 2021-09-07
HENGDIAN GRP DMEGC MAGNETICS CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The low-temperature performance of the material obtained by this method is better, but this method has undergone several heat treatments successively, the production process is complicated and the energy consumption is high, the polymer precursor needs to be dissolved in the organic solvent, and the organic solvent needs to be evaporated to dryness, and the cost is high and not friendly to the environment
Another example is CN108270033A which discloses a method for preparing a low-temperature lithium-ion battery electrolyte. The invention includes a non-aqueous organic solvent, a lithium salt, a functional auxiliary agent 1 and a functional auxiliary agent 2, and the described functional auxiliary agent 1 is fluoroethylene carbonate Esters, the second functional additive is propenyl-1,3-propane sultone This method can obtain better low-temperature charge and discharge efficiency when applied to lithium-ion batteries, but the low-temperature rate problem is still serious

Method used

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  • A cylindrical lithium-ion battery
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  • A cylindrical lithium-ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] This embodiment provides a cylindrical lithium-ion battery, including an electrode group, an electrolyte, a casing, a safety valve, and a cap, and the electrode group includes a positive pole piece, a negative pole piece, and an The separator, the positive pole piece contains lithium carbonate.

[0053] Preparation of positive electrode sheet:

[0054] The preparation method of the positive electrode sheet includes: adding 100 parts by weight of positive electrode active material LiNiCoMn, 1-3 parts by weight of binder PVDF, 0.5-3 parts by weight of carbon nanotubes, and 0.1-1 parts by weight of lithium carbonate to 40 parts by weight NMP, and then stirred in a vacuum mixer to form a stable and uniform dispersed positive electrode slurry. The working conditions of the vacuum mixer are: the temperature is controlled at 25°C, the stirring speed is controlled at 35rpm, the dispersion speed is controlled at 1500rpm, and the time is controlled at 150min.

[0055] Coat the o...

Embodiment 2

[0064] The difference between this embodiment and embodiment 1 is:

[0065] Electrolyte is made of solvent and lithium salt additive, and described solvent is the mixture of ethylene carbonate, methyl ethyl carbonate, diethyl carbonate and propylene carbonate by mass ratio 4:2:7:2, and described lithium salt Additives are LiODFB, LiPF 2 o 2 and LiTFSI in a mass ratio of 5:2:3, the mass ratio of the solvent and the lithium salt additive is 38:7.

[0066] The added amount of the electrolyte is 5g.

[0067] Test the cylindrical lithium-ion battery, the test conditions are: 3C charge 10C discharge cycle 10 times at -20°C, constant current and constant voltage to 4.2V, then put in the oven, and rise to 135±2 at a rate of 5°C / min After holding for 10 minutes at ℃, test the charge and discharge performance. The test results are shown in Table 2, where DM-16#, DM-17#, and DM-18# respectively represent three cylindrical lithium-ion batteries of the same batch.

[0068] Table 2

...

Embodiment 3

[0072] The difference between this embodiment and embodiment 1 is:

[0073] During the preparation of the positive electrode sheet, the positive electrode slurry is coated on both sides of the electrode sheet, and the surface density on both sides is 255g / m 2 ;

[0074] In the preparation process of the negative electrode sheet, the negative electrode slurry is coated on both sides of the electrode sheet, and the surface density of one side along the length direction is changed from 126g / m 2 Gradient to 114g / m 2 , the areal density of the other side along the same direction by 114g / m 2 Gradient to 126g / m 2 , and ensure that the sum of the surface densities on both sides corresponding to each position of the negative pole piece in the entire length direction is a fixed value of 240g / m 2 .

[0075] The obtained cylindrical lithium-ion battery was tested under the same conditions as in Example 1 and Example 2, and it also had excellent low-temperature rate performance, safet...

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Abstract

The invention discloses a cylindrical lithium-ion battery, which includes an electrode group, an electrolyte, a casing, a safety valve and a cap. The electrode group includes a positive pole piece, a negative pole piece, and a The diaphragm, the positive pole piece contains carbonate. The present invention combines the air pressure-resistant characteristics of the cylindrical lithium-ion battery with its own safety valve and its shell (the steel shell is commonly used), and designs to add carbonate inorganic substances that are easy to decompose and produce gas under high voltage conditions into the positive electrode formula. Under high temperature and high voltage conditions, carbonate inorganic matter decomposes to produce gas, which makes the safety valve open, thus solving the problem of easy fire and explosion during high rate charge and discharge under low temperature conditions. The invention further optimizes the formula of the electrolyte, which can improve the high-rate charge-discharge performance of the cylindrical lithium-ion battery in a low-temperature environment and the charge-discharge performance after high-temperature storage for a period of time.

Description

technical field [0001] The invention belongs to the technical field of new energy and relates to a cylindrical lithium-ion battery, in particular to a cylindrical lithium-ion battery with excellent high-rate charge-discharge performance and excellent safety performance under low temperature conditions. Background technique [0002] As a new generation of rechargeable battery products, lithium batteries have the characteristics of high voltage, high energy density, long cycle life, no memory effect, and no pollution compared with traditional lead-acid, nickel-cadmium, and nickel-metal hydride batteries. Since Sony invented the 18650 lithium-ion battery, lithium-ion batteries have been widely used in 3C digital, automotive power, medium and high rate and other fields. [0003] Cylindrical batteries, especially 18650 lithium-ion batteries, due to their own structural characteristics and the standardization of their models, have the highest level of automation in the production ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0525H01M50/317H01M4/36H01M4/505H01M4/525H01M10/0563
CPCH01M4/364H01M4/505H01M4/525H01M10/0525H01M10/0563H01M50/30Y02E60/10
Inventor 潘凌波
Owner HENGDIAN GRP DMEGC MAGNETICS CO LTD
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