Method for improving electrolytic solution resistance of binder in lithium battery negative electrode sheet by irradiation

A technology of negative pole piece and electrolyte, which is applied in the field of irradiation to improve the electrolyte resistance of the binder in the negative pole piece of lithium batteries, can solve the problems of incomplete crosslinking, non-crosslinking, limited chemical synthesis, etc., and achieve The effects of reduced processing procedures, short irradiation time, and simple preparation process

Inactive Publication Date: 2020-08-28
INST OF HIGH ENERGY PHYSICS CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For SBR, it is usually a cross-linked structure, but limited by the characteristics of chemical synthesis, it usually cannot be completely cross-linked inside, and there is a certain amount of uncross-linked double bonds

Method used

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  • Method for improving electrolytic solution resistance of binder in lithium battery negative electrode sheet by irradiation
  • Method for improving electrolytic solution resistance of binder in lithium battery negative electrode sheet by irradiation
  • Method for improving electrolytic solution resistance of binder in lithium battery negative electrode sheet by irradiation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Preparation of positive electrode sheet for lithium ion battery:

[0029] Mix the positive electrode active material nickel cobalt lithium manganate, conductive carbon, and binder PVDF in the solvent NMP according to the mass ratio of 96:2:2, and stir evenly to obtain the positive electrode slurry. The positive electrode slurry obtained is coated on a 12 μm aluminum foil, dried, and cold-pressed to obtain a compacted density of 3.3 g / cm 3 The pole piece is then cut and welded to obtain the positive pole piece.

[0030] Preparation of lithium ion battery negative electrode sheet:

[0031] Add the negative electrode active materials natural graphite, conductive carbon, CMC-Na, and SBR into deionized water according to the mass ratio of 96:1:1:2, and mix well to obtain the negative electrode slurry, and then coat the negative electrode slurry on 8 μm thick The two sides of the metal copper foil are dried into a negative electrode sheet with a certain degree of flexibilit...

Embodiment 2

[0040] Different from Example 1 is the irradiation of lithium ion battery:

[0041] Lithium-ion battery dry cells are placed on the under-beam device under the irradiation accelerator, loaded on a trolley, and laid out in an orderly manner. Adjust the parameters of the irradiation equipment. By adjusting the energy of the accelerator and the speed of the device under the accelerator beam, the dose rate is 5kGy / s, and the lithium-ion battery is irradiated. The irradiation dose is 20kGy, so that CMC-Na and SBR produce alternating couplet. Then take out the lithium-ion battery dry cell from the trolley. The electrolyte is perfused through the liquid injection port, and then lithium-ion batteries are produced through processes such as formation and capacity, and the performance of the batteries is tested.

[0042] All the other are with embodiment 1.

Embodiment 3

[0044] Different from Example 1 is the irradiation of lithium ion battery:

[0045] Lithium-ion battery dry cells are placed on the under-beam device under the irradiation accelerator, loaded on a trolley, and laid out in an orderly manner. Adjust the parameters of the irradiation equipment. By adjusting the energy of the accelerator and the speed of the device under the accelerator beam, the dose rate is 5kGy / s, and the lithium-ion battery is irradiated. The irradiation dose is 30kGy, so that CMC-Na and SBR produce alternating couplet. Then take out the lithium-ion battery dry cell from the trolley. The electrolyte is perfused through the liquid injection port, and then lithium-ion batteries are produced through processes such as formation and capacity, and the performance of the batteries is tested.

[0046] All the other are with embodiment 1.

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Abstract

The invention discloses a method for improving electrolytic solution resistance of a lithium battery negative electrode binder through irradiation, and belongs to the technical field of lithium batteries. The method comprises the following steps: preparing a lithium battery containing a negative electrode taking sodium carboxymethyl cellulose (CMC-Na) and styrene-butadiene rubber emulsion (SBR) asbinders; and placing the whole battery on an under-beam device of an electron beam irradiation accelerator, and irradiating the whole lithium ion battery, wherein the irradiation dose is 10 to 100 kGy, the irradiation dose rate is 2-10 kGy/s, and in the negative electrode, CMC-Na and SBR can generate intramolecular and intermolecular chemical cross-linking so as to improve the electrolytic solution resistance of the binders CMC-Na and SBR in the negative electrode sheet, reduce the swelling of the binders CMC-Na and SBR in the electrolytic solution, reduce the thickness expansion rate of thenegative electrode sheet in the battery circulation process, improve the capacity retention rate of the battery and prolong the service life of the battery. The process is simple and easy to implement, low in cost and suitable for consumer electronic lithium batteries and power type lithium batteries.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and relates to a method for improving the electrolyte resistance performance of a binder in a negative pole piece of a lithium battery by irradiation. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, and long cycle life, and are currently widely used in digital products such as mobile phones and notebook computers, as well as energy storage devices for power vehicles. Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, separators, and electrolytes. The negative electrodes usually use natural graphite, artificial graphite, mesophase microspheres, etc. as active materials, and usually use water-based systems. Sodium plain), SBR (styrene-butadiene rubber) as binder, has the advantages of environmental protection and low cost. The positive electrode usually uses lithium metal oxides, suc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/058H01M4/62
CPCH01M10/058H01M4/622Y02E60/10Y02P70/50
Inventor 罗敏邵阳马玲玲徐殿斗
Owner INST OF HIGH ENERGY PHYSICS CHINESE ACADEMY OF SCI
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