CN-118825183-B - High-load dry electrode and preparation method thereof

CN118825183BCN 118825183 BCN118825183 BCN 118825183BCN-118825183-B

Abstract

The application discloses a preparation method of a high-load dry electrode in the technical field of energy storage batteries, which comprises the following steps of S1, stirring and mixing a conductive agent and a binder to obtain an intermediate 1, S2, stirring the intermediate 1 to obtain an intermediate 2 through low-degree fibrosis, S3, adding an active material into the intermediate 2 to obtain an intermediate 3 through low-speed stirring, S4, stirring the intermediate 3 to obtain a granular active material mixture through fibrosis, S5, repeatedly carrying out repeated pressure-extension thinning on the active material mixture by using hot-pressing equipment until the compaction density reaches a set value to obtain a plurality of self-supporting films with high compaction density, S6, sequentially bonding and compounding the plurality of self-supporting films onto a current collector by using conductive adhesive to obtain a composite self-supporting film, and carrying out hot pressing on the composite self-supporting film and the current collector to obtain a high-load dry electrode plate. Thin films with higher compaction density are obtained through repeated thinning, and the pole pieces with high load capacity are obtained through a lamination compounding method.

Inventors

LIU FULIANG
Diao Siqiang
HU JINFEI
TIAN HONGSONG
CHEN XIAOTAO
HU HONGRUI
SHI BIN
Ban Xiaohan
CHEN ANGUO
LUO FENGLAN
TIAN WENYAN
LI YIFAN
ZHOU XIONG

Assignees

贵州梅岭电源有限公司

Dates

Publication Date: 20260512
Application Date: 20240820

Claims (3)

1. A preparation method of a high-load dry electrode is characterized by comprising the following steps, S1, stirring and mixing a conductive agent and a binder under a certain low temperature and rotating speed condition to obtain an intermediate 1; S2, constructing a conductive network, namely stirring the intermediate 1 at a certain low temperature and a rotating speed to carry out low-degree fibrosis to obtain an intermediate 2; S3, mixing the active materials, namely adding the active materials into the intermediate 2, and stirring at a low speed to obtain an intermediate 3; S4, fiberizing the intermediate 3 by stirring to obtain a granular active material mixture; S5, preparing a high-compaction self-supporting film, namely repeatedly carrying out pressure-extension thinning on the active material mixture for a plurality of times by using hot-pressing equipment until the compaction density reaches a set value, so as to obtain a plurality of self-supporting films with high compaction density; S6, preparing a high-load dry electrode slice, namely sequentially bonding and compounding a plurality of self-supporting films by using conductive adhesive to obtain a composite self-supporting film until the load capacity reaches a design value, and carrying out hot pressing on the composite self-supporting film and a current collector to obtain the high-load dry electrode slice; The adhesive is polytetrafluoroethylene PTFE, the adhesive accounts for 1% -5%, the conductive agent is one or more of carbon nano tubes CNTs, superconducting carbon black SP, conductive graphite KS-6 and ketjen black KB, the conductive agent accounts for 1% -5%, the stirring speed is controlled to be 200-800 r/min, the mixing temperature is 5-25 ℃, the mixing time is 10-30 min, the stirring speed is 1500-3000 r/min, the mixing temperature is 25-50 ℃, the mixing time is 10-30 min, the stirring speed is controlled to be 200-800 r/min, the stirring time is 10-30 min, the stirring speed is controlled to be 3500-600 r/min for the intermediate 3 by using high-speed shearing fiber equipment, the stirring time is 10-30 min, the rolling temperature of the S5 is controlled to be 80-150 ℃ and the hot pressing temperature of the S6 is 80-150 ℃, and the active material is added to the intermediate 2 for multiple times.
2. The method for preparing the high-load dry electrode according to claim 1, wherein the active material is LiCoO 2 、LiMn 2 O 4 、LiFePO 4 、LiNi 1-x-y Co y Mn x O 2 、LiNi 1-x-y Co y Al x O 2 、LiM x Mn 2-x O 4 ,, wherein M is Fe and Co doped anode material for the lithium ion battery or is graphite, soft carbon and hard carbon anode material for the lithium ion battery, and the mass ratio of the active material is 90% -98%.
3. An electrode prepared by the high-load dry electrode preparation method according to any one of claims 1 or 2.

Description

High-load dry electrode and preparation method thereof Technical Field The invention relates to the technical field of chemical energy storage batteries, in particular to a high-load dry electrode and a preparation method thereof. Background The lithium ion battery is used as a new generation electrochemical energy storage power supply, and is widely applied to the fields of electronic products such as power automobiles, smart grids, communication base stations, unmanned aerial vehicles and the like by virtue of the advantages of high energy density, high working voltage, small self-discharge rate, long cycle life and the like. Research on the preparation of the high-load electrode plate is one of important directions for improving the energy density of the lithium ion battery, and compared with the traditional wet electrode preparation process, the dry process is more suitable for the preparation of the high-load electrode, has higher theoretical energy density, and has the advantages of low manufacturing cost, small pollution and the like. The traditional dry electrode preparation method comprises the steps of mixing, fiberizing, hot pressing and thinning, and compositing a self-supporting film and a current collector, wherein the hot pressing and thinning step is to hot press the fiberized powder into a film with thicker thickness, the thickness is generally more than or equal to 500um, and then repeatedly hot pressing is carried out to thin the film to the required load capacity, so that for the pole piece with high load capacity, the hot pressing and thinning times are less, the compaction density is low, and the thickness is thicker. However, the traditional dry method high-load electrode has the problems of low compaction density, large thickness of the pole piece, high resistivity and the like, so that the prepared lithium ion battery has serious polarization and poor rate capability. Therefore, the application provides a high-load dry electrode preparation process with high compaction density and high conductivity. Disclosure of Invention The invention aims to provide a high-load dry electrode and a preparation method thereof, wherein a thin film sheet with higher compaction density is obtained through repeated thinning, and a high-load pole piece is obtained through a lamination compounding method. In order to achieve the above purpose, the present invention provides the following technical solutions: a preparation method of a high-load dry electrode comprises the following steps, S1, stirring and mixing a conductive agent and a binder under a certain low temperature and rotating speed condition to obtain an intermediate 1; S2, constructing a conductive network, namely stirring the intermediate 1 at a certain low temperature and a rotating speed to carry out low-degree fibrosis to obtain an intermediate 2; S3, mixing the active materials, namely adding the active materials into the intermediate 2, and stirring at a low speed to obtain an intermediate 3; S4, fiberizing the intermediate 3 by stirring to obtain a granular active material mixture; S5, preparing a high-compaction self-supporting film, namely repeatedly carrying out pressure-extension thinning on the active material mixture for a plurality of times by using hot-pressing equipment until the compaction density reaches a set value, so as to obtain a plurality of self-supporting films with high compaction density; And S6, preparing the high-load dry electrode slice, namely sequentially bonding and compounding a plurality of self-supporting films on the current collector by using conductive adhesive to obtain a composite self-supporting film until the load capacity reaches a design value, and carrying out hot pressing on the composite self-supporting film and the current collector to obtain the high-load dry electrode slice. The working principle and the beneficial effects of the invention are as follows: According to the application, the low-degree fibrosis of the binder is realized by controlling the stirring temperature and the rotating speed, a three-dimensional conductive network structure in which the conductive agent and the binder are uniformly mixed is obtained, and the active material is uniformly dispersed into the three-dimensional conductive network structure by adding the active material for a plurality of times for mixing, so that the high-conductivity fibrosis powder is obtained. The active material of the fiberized powder prepared by the method is contacted with the conductive agent more uniformly and tightly, so that the conductivity is higher, the compaction is easier, and the preparation of the high-compaction self-supporting film is more facilitated; In addition, the high-load dry electrode slice is prepared by compounding a plurality of layers of high-compaction films. The electrode plate prepared by the method has the advantages that the compaction density of the electrode plate is higher, on one hand, the active mater