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Pre-lithiation device and method for lithium ion battery negative electrode pole piece with controllable pre-lithiation degree

A lithium-ion battery and negative pole piece technology, which is applied in battery electrodes, secondary batteries, secondary battery charging/discharging, etc., can solve the problems of low safety and uncontrollable degree, and achieve high safety and good uniformity , the effect of preventing short circuit

Inactive Publication Date: 2019-03-26
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is mainly to propose a controllable lithium-ion battery negative electrode material (especially silicon-based negative electrode material) for the pre-lithiation of the electrode sheet of the existing pre-lithiation method. Schematic diagram of lithiation method and industrial application device

Method used

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  • Pre-lithiation device and method for lithium ion battery negative electrode pole piece with controllable pre-lithiation degree
  • Pre-lithiation device and method for lithium ion battery negative electrode pole piece with controllable pre-lithiation degree
  • Pre-lithiation device and method for lithium ion battery negative electrode pole piece with controllable pre-lithiation degree

Examples

Experimental program
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Effect test

Embodiment 1

[0041] In a nitrogen atmosphere, place a piece of pure silicon pole piece on a clean splint, add 200 μl of electrolyte dropwise, place the diaphragm on the pole piece, and add 200 μl of electrolyte on it, and place the pole piece 1 mm wider than the pole piece on all sides. The lithium metal sheet is placed on the diaphragm, and another clean splint is placed on the lithium metal sheet. Lead two wires from the pole piece and metal lithium piece respectively, form a closed circuit with a resistor and a switch with a resistance value of 300Ω, and connect a voltmeter to monitor the voltage between the two pole pieces. Turn on the switch, remove the pole piece after pre-lithiation for 5 hours to complete the pre-lithiation operation, so that the pre-lithiation amount in pure silicon is 30% of the total capacity of the negative pole piece.

Embodiment 2

[0043] In an argon atmosphere, place a pure SiO pole piece on a clean splint, add 200 μl of electrolyte dropwise, place the diaphragm on the pole piece, and drop 200 μl of electrolyte on it, making the surrounding area 3mm wider than the pole piece. The metal lithium sheet is placed on the diaphragm, and another clean splint is placed on the metal lithium sheet. Lead two wires from the pole piece and metal lithium piece respectively, form a closed circuit with a resistor and a switch with a resistance value of 100Ω, and connect a voltmeter to monitor the voltage between the two pole pieces. Turn on the switch, remove the pole piece after pre-lithiation for 2 hours to complete the pre-lithiation operation, so that the pre-lithiation amount in pure SiO is 45% of the total capacity of the negative pole piece.

Embodiment 3

[0045] Place a piece of pure SiO on a clean plywood in an argon atmosphere 2 For the pole piece, add 200 μl of electrolyte dropwise, place the diaphragm on the pole piece, and add 200 μl of electrolyte dropwise on it, place a lithium metal sheet with a width of 2 mm on all sides than the pole piece on the diaphragm, and place another clean splint on the pole piece. on the lithium metal sheet. Lead two wires from the pole piece and the lithium metal piece respectively, form a closed circuit with a resistor and a switch with a resistance value of 1000Ω, and connect a voltmeter to monitor the voltage between the two pole pieces. Turn on the switch, remove the pole piece after pre-lithiation for 24 hours to complete the pre-lithiation operation, so that pure SiO 2 The amount of pre-lithiation is 70% of the total capacity of the negative electrode sheet.

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Abstract

The invention provides a pre-lithiation device and method for a lithium ion battery negative electrode pole piece with a controllable pre-lithiation degree. The method comprises the following steps: assembling a pole piece coated with a negative electrode material and a metal lithium sheet under an inert atmosphere to form a semi-battery model; connecting a resistor with a certain resistance valuebetween two semi-battery electrodes; carrying out pre-lithiation through discharging a battery; and connecting a voltmeter to monitor voltage of two poles. The aim of controllable pre-lithiation is realized through controlling the resistance value of the resistor, lithiation time and the voltage of the two poles and the like. After the pre-lithiation is carried out for certain time, the pole piece does not need to be dried and used electrolyte does not need to be replaced and can be directly assembled with a positive electrode pole piece to assemble the whole battery. The battery subjected tothe pre-lithiation of the method is charged and discharged under the current density of 0.5 to 1.0Ag<-1> and the first-week efficiency can reach 90 to 100 percent. The method is simple to operate, low in cost, good in pre-lithiation uniformity and controllable pre-lithiation degree; the electrolyte does not need to be replaced and the pole piece does not need to be dried after the pre-lithiationis carried out; and the method is suitable for industrial popularization and application.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method and device for pre-lithiation of negative pole pieces of lithium-ion batteries. Background technique [0002] Since the commercialization of lithium-ion batteries, lithium-ion batteries have been widely used in communications, portable electronic devices, transportation, etc. due to their advantages such as high energy density, stable cycle performance, lightness and convenience, etc., and have developed rapidly in recent years. Quick boost. [0003] Currently, emerging applications such as electric vehicles and large-scale energy storage devices place higher and higher requirements on the energy density of lithium-ion batteries. However, during the first charge and discharge process of the battery, the electrolyte will undergo reductive decomposition on the surface of the positive and negative active materials, forming a layer of "solid electrolyte interf...

Claims

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Application Information

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IPC IPC(8): H01M4/139H01M10/0525H01M10/44
CPCH01M4/139H01M10/0525H01M10/44Y02E60/10
Inventor 吴昊王连邦郑丽华
Owner ZHEJIANG UNIV OF TECH
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