Dry electrode and preparation method thereof

A dry electrode and conductive agent technology, which is applied in electrode manufacturing, electrode rolling/calendering, battery electrodes, etc., can solve the problems affecting the power performance of the battery cell, limiting the amount of active material, and the content of binders, etc., to achieve the appearance of molding Good, prevent powder dropping and cracking, high peel strength effect

Inactive Publication Date: 2021-06-25
KUNSHAN BAOTRON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the vast majority of dry electrode preparation methods still have the following disadvantages: 1) high-speed dispersion equipment is required to mix the positive or negative electrode powder evenly and perform fibrillation treatment, but the binder (such as polytetrafluoroethylene ) content is high, which will limit the amount of active material; 2) The electrode powder after production is subjected to high-pressure electrode production process, which is prone to belt breakage; 3) The thickness of the current electrode production is too large (usually 300 μm ~ 1000 μm), which will affect The power performance of the battery; 4) The interface of the battery formed by the dry electrode is poor (the SEI film formation process is affected); 5) The electrode piece after the dry electrode is stored at room temperature for a week and it is easy to crack

Method used

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preparation example Construction

[0062] A preparation method for a dry electrode, comprising the steps of:

[0063] Step 1: preparing powder, which at least includes the following raw materials in mass percentage:

[0064] Active substance 90%~97%,

[0065] Conductive agent 0.1%~2%,

[0066] Adhesive 2.9%~9.9%;

[0067] Step 2: Coating powder accounting for 10% to 90% of the total mass of the powder on the current collector, performing multiple rolling treatments, and preparing an intermediate;

[0068] During the preparation of the intermediate, at least one rolling treatment has a pressure roller traveling direction parallel to the coating direction;

[0069] Step 3: Coating the rest of the powder on the intermediate, and performing rolling treatment to prepare a dry electrode.

[0070] The preparation method of the dry electrode provided by the invention includes a specific powder composition, a step-by-step feeding method and a specific rolling treatment method. Specifically, in terms of mass percent...

Embodiment 1

[0148] This embodiment provides a conductive rubber material, a preparation method thereof, and a current collector aluminum foil coated with a conductive coating.

[0149] (1) The conductive adhesive is prepared from the following raw materials in mass percentage:

[0150]

[0151]

[0152] Wherein the sheet diameter of the graphene is 30 μm, the diameter of the multi-walled carbon nanotube is 5 nm to 70 nm, and the aspect ratio is 1000 to 1500.

[0153] (2) Prepare conductive paste:

[0154] Ultrasonic dispersion of graphene, multi-walled carbon nanotubes and sodium dodecylbenzenesulfonate in deionized water with an ultrasonic instrument to obtain a mixed solution A, the ultrasonic power is 1500W, and the ultrasonic time is 80min;

[0155] Mixing the adhesive and deionized water to obtain a mixed solution B;

[0156] The mixed solution A and the mixed solution B were stirred and mixed uniformly for 100 min to obtain a conductive paste.

[0157] (3) Preparation of po...

Embodiment 2

[0160] This embodiment provides positive electrode powder and a preparation method thereof.

[0161] (1) The positive electrode powder 1 is prepared from the following raw materials in mass percentage:

[0162] Lithium iron phosphate 92.3%;

[0163] Graphene 0.32%;

[0164] PTFE 7.38%.

[0165] The positive electrode powder 2 is prepared from the following raw materials in mass percentage:

[0166]

[0167] (2) Preparation of powder:

[0168] Preparation of powder 1: Using a three-dimensional dry-process high-speed dispersion equipment, the lithium iron phosphate, carbon black and PTFE were uniformly mixed and fibrillated to obtain positive electrode powder 1, which was set aside.

[0169] Preparation of powder 2: Using a three-dimensional dry-process high-speed dispersion equipment, the lithium iron phosphate, graphene, carbon nanotubes, and PTFE were uniformly mixed and fibrillated to obtain positive electrode powder 2, which was set aside.

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Abstract

The invention relates to a dry electrode and a preparation method thereof. The preparation method of the dry electrode comprises the following steps: firstly, preparing a powder material, wherein the total powder material is prepared from raw materials consisting of in percentage by mass, 90-95% of an active substance, 0.1%-2% of a conductive agent and 4.9%-9.9% of an adhesive; coating a current collector with the powder accounting for 10%-90% of the total mass of the powder, and carrying out rolling treatment multiple times to prepare an intermediate, wherein when the intermediate is prepared, the advancing direction of a compression roller used in at least one rolling treatment operation is enabled to be parallel to a coating direction; and coating the intermediate with remaining powder and carrying out rolling treatment to prepare the dry electrode. The thickness of the dry electrode can reach 100-300 [mu]m, the thickness of a pole piece is relatively stable (controlled within +/-6 [mu]m), peel strength is high, formed appearance is good, product requirements are met, operation is simple, and the dry electrode is suitable for industrial production and has wide application prospects.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a dry electrode and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density and good cycle performance, and have been widely used in many fields, especially in the field of electric vehicles, which have higher requirements for battery energy density and safety. [0003] With the improvement of the cruising range of electric vehicles, there is an urgent need for batteries to obtain higher energy density. In order to achieve this goal, the current technical route is mainly to develop in the direction of ternary high-nickel and SiO or in the direction of high-voltage route. It cannot be ignored that with the improvement of high energy density, the accompanying defects such as reduced safety and increased cost are also stumbling blocks that limit the further promotion of lithium batteries; and cost reduction can not only s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/139
CPCH01M4/0404H01M4/0416H01M4/0435H01M4/139Y02E60/10
Inventor 王洪伟刘丰
Owner KUNSHAN BAOTRON NEW ENERGY TECH CO LTD
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