Electrode pole piece and electrochemical device comprising same

A pole piece and anode technology, applied in the field of electrochemical devices, can solve problems such as electrochemical short circuit and reduce the safety of battery cells, and achieve the effects of improving safety, improving uneven lithium deposition, and reducing the probability of lithium dendrite formation.

Inactive Publication Date: 2019-07-12
DONGGUAN POWERAMP TECH LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The formation of lithium dendrites will to a large extent puncture the separator between the anode electrode and the cathode electrode, resulting in direct contact between the cathode electrode and the anode electrode, resulting in an electrochemical short circuit, which greatly reduces the safety of the cell.

Method used

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  • Electrode pole piece and electrochemical device comprising same
  • Electrode pole piece and electrochemical device comprising same
  • Electrode pole piece and electrochemical device comprising same

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0116] Preparation of lithium-ion batteries

[0117] The cathode active material is prepared into a lithium ion battery by the following preparation method. Specifically, the cathode active material, conductive agent, and binder are fully stirred and mixed in N-methylpyrrolidone according to a certain weight ratio to make a cathode slurry, and then the obtained cathode slurry is evenly coated on the cathode current collector The front and back surfaces of the aluminum foil are dried at 85°C to obtain a cathode active material layer, and then cold pressed, stripped, cut into pieces, and cathode tabs are welded to obtain a cathode sheet.

[0118] Fully stir and mix the anode active material, binder, and dispersant in deionized water according to a certain weight ratio to make an anode slurry, and then evenly coat the anode slurry on the front and back of the anode current collector copper foil , and then dried at 85°C to form an anode active material layer, and then perform col...

Embodiment 1-4 and comparative example 1-4

[0126] Examples 1-4 involved zone coating the cathode pole piece without zone coating the anode pole piece. The following will specifically describe the preparation method of the cathode sheet in Examples 1-4 and Comparative Examples 1-4:

[0127] The preparation method of the electrode pole piece of embodiment 1:

[0128] (1) Preparation of slurry

[0129] Negative electrode NCM811 / NCM523 slurry: Negative active ingredient NCM811 (220mAh / g) / NCM523 (180mAh / g), conductive agent Super-P and binder polyvinylidene fluoride PVDF by 97%: 1.5%: 1.5% by weight Proportionally mixed and diluted with an appropriate amount of N-methylpyrrolidone, then stirred in a vacuum mixer to form a uniform cathode slurry.

[0130] Anode graphite slurry: mix positive active component graphite, binder styrene-butadiene rubber SBR and dispersant carboxymethyl cellulose CMC in a 97%:1%:2% weight ratio, and dilute with an appropriate amount of distilled water, and then mix in a vacuum mixer Stir to for...

Embodiment 5-7 and comparative example 5-6

[0153] Examples 5-7 and Comparative Examples 5-6 only involve zone coating on the anode pole piece, but not zone coating on the cathode pole piece. The following will specifically describe the preparation method of the anode sheet in Examples 5-7 and Comparative Examples 5-6:

[0154] The preparation method of the electrode pole piece of embodiment 5:

[0155] (1) Preparation of slurry

[0156] Anode graphite / GNS slurry: positive active component graphite (370mAh / g) / GNS (740mAh / g), binder styrene-butadiene rubber SBR and dispersant carboxymethyl cellulose CMC according to 97%:1%:2% Mixed in proportion by weight, diluted with appropriate amount of distilled water, and then stirred in a vacuum mixer to form a uniform anode slurry.

[0157] Cathode NCM811 slurry: mix the cathode active component NCM811 (220mAh / g), the conductive agent Super-P and the binder polyvinylidene fluoride PVDF in a ratio of 97%:1.5%:1.5% by weight, and add an appropriate amount of NCM Diluted with bas...

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Abstract

The invention relates to an electrode pole piece and an electrochemical device comprising the same. The positive pole piece comprises a positive first region and a positive second region, and the unitarea capacity CsA2 of the positive second region is larger than or equal to the unit area capacity CsA1 of the positive first region. The negative pole piece comprises a negative first region and a negative second region, wherein the unit area capacity CsC2 of the negative second region is smaller than or equal to 98% of the unit area capacity CsC1 of the negative first region. When the positivepole piece and / or the negative pole piece are / or applied to the electrochemical device, the formation of the lithium dendrites can be effectively reduced, and the safety of the electrochemical devicecan be improved.

Description

technical field [0001] The present application relates to the field of energy storage technology, in particular to an electrode pole piece and an electrochemical device including the electrode pole piece. Background technique [0002] With the popularity of consumer electronics products such as notebook computers, mobile phones, handheld game consoles, tablet computers, mobile power supplies and drones, people have increasingly strict requirements on electrochemical devices (eg, batteries). For example, people not only require the battery to be light, but also require the battery to have a high capacity and a long working life. Among many batteries, lithium-ion batteries have occupied a mainstream position in the market due to their outstanding advantages such as high energy density, high safety, low self-discharge, no memory effect, and long working life. [0003] However, until now, the safety of electrochemical devices has not been effectively guaranteed. For example, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/66H01M4/70H01M10/0525
CPCH01M4/66H01M4/70H01M4/667H01M10/0525Y02E60/10H01M2004/027H01M2004/028H01M2004/021H01M4/1393H01M4/5825H01M4/525H01M4/587H01M4/386H01M4/0404H01M4/366H01M10/052
Inventor 王慧鑫黄思林余红明程晟
Owner DONGGUAN POWERAMP TECH LTD
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