CN-122006980-A - Bubble-prevention coating system and method for coating lithium battery pole piece

CN122006980ACN 122006980 ACN122006980 ACN 122006980ACN-122006980-A

Abstract

The application provides an anti-bubble coating system and method for coating a lithium battery pole piece, which belong to the technical field of battery manufacturing and comprise a main coating system, a main coating system and a main coating system, wherein the main coating system comprises a coating feeding tank, a screw pump, a filter and a coating die head; the material receiving and refluxing unit comprises a material receiving funnel, a backflow pipeline, a backflow conveying pump, an auxiliary tank, a transfer pipeline and a transfer pump, wherein the material receiving funnel is arranged on one side of a coating die head, a feeding hole of the material receiving funnel faces the coating die head, one end of the backflow pipeline is connected with a discharging hole of the material receiving funnel, the other end of the backflow pipeline is connected with a feeding hole of the auxiliary tank, the backflow conveying pump is arranged on the backflow pipeline, one end of the transfer pipeline is connected with a discharging hole of the auxiliary tank, the other end of the transfer pipeline is connected with a feeding hole of a coating charging tank, the transfer pump is arranged on the transfer pipeline, and a vacuum pump is connected to the auxiliary tank. By the anti-bubble coating system and the anti-bubble coating method for coating the lithium battery pole piece, the scrapping condition of the pole piece can be reduced, the production cost is reduced, and the quality of the battery pole piece is improved.

Inventors

SU QIAN
QIN XIANGFEI
SHI XINMING
SONG SHUANG
LIANG YUWANG
LI LINGDONG
WEI ANG
WEN XIAOLEI
CHEN SHUAI

Assignees

山东吉利欣旺达动力电池有限公司

Dates

Publication Date: 20260512
Application Date: 20260320

Claims (9)

1. An anti-bubble coating system for coating a lithium battery pole piece, comprising: the main coating system comprises a coating feeding tank, a screw pump, a filter and a coating die head, wherein one end of the screw pump is connected with a discharge hole of the coating feeding tank, the other end of the screw pump is connected with the coating die head, and the filter is arranged between the screw pump and the coating die head; The material receiving and refluxing unit comprises a material receiving funnel, a refluxing pipeline, a refluxing conveying pump, an auxiliary tank, a transferring pipeline and a transferring pump, wherein the material receiving funnel is arranged on one side of the coating die head, a feeding port of the material receiving funnel faces the coating die head, one end of the refluxing pipeline is connected with a discharging port of the material receiving funnel, the other end of the refluxing pipeline is connected with a feeding port of the auxiliary tank, the refluxing conveying pump is arranged on the refluxing pipeline, one end of the transferring pipeline is connected with a discharging port of the auxiliary tank, the other end of the transferring pipeline is connected with a feeding port of the coating feeding tank, the transferring pump is arranged on the transferring pipeline, a vacuum pump is connected to the auxiliary tank and used for enabling the internal pressure of the auxiliary tank to be under preset pressure.
2. The anti-bubble coating system for coating a lithium battery pole piece according to claim 1, wherein: a first filtering device is arranged between the backflow pipeline and the feed inlet of the auxiliary tank and is used for carrying out primary filtration on the negative electrode slurry.
3. The anti-bubble coating system for coating a lithium battery pole piece according to claim 1, wherein: a second filtering device is arranged between the transfer pipeline and the feed inlet of the coating charging tank and is used for filtering the recovered negative electrode slurry.
4. The anti-bubble coating system for coating a lithium battery pole piece according to claim 1, wherein: the material of the receiving hopper, the reflux pipeline and the transfer pipeline is stainless steel.
5. The anti-bubble coating system for coating a lithium battery pole piece according to claim 1, wherein: the magnitude of the preset pressure is-0.08 MPa to-0.06 MPa.
6. An anti-bubble coating method for coating a lithium battery pole piece, which is applied to an anti-bubble coating system for coating a lithium battery pole piece according to any one of claims 1 to 5, and is characterized in that the method comprises the following steps: Injecting negative electrode slurry into the coating feeding tank, and adjusting the discharge port of the coating die head to face the receiving hopper; Starting a main screw pump and a reflux conveying pump, enabling negative electrode slurry to sequentially flow through the main screw pump, a filter and a coating die head, enabling the negative electrode slurry to enter a secondary tank through a receiving hopper and a reflux pipeline, adjusting the direction of a discharge hole of the coating die head again after a first preset time period is reached, and starting coating of a lithium battery pole piece; when the negative electrode slurry in the auxiliary tank is accumulated to a preset liquid level, starting a vacuum pump and a stirrer in the auxiliary tank, keeping the internal pressure of the auxiliary tank at the preset pressure, continuously stirring the negative electrode slurry in the auxiliary tank until a second preset time period is reached, starting a transfer pump, and re-injecting the negative electrode slurry in the auxiliary tank into the coating charging tank through a transfer pipeline.
7. The bubble preventing coating method for coating a lithium battery pole piece according to claim 6, characterized in that: The first period of time is 5 hours.
8. The anti-bubble coating system for lithium battery pole piece coating of claim 6, wherein: The preset liquid level is two-thirds of the volume of the auxiliary tank.
9. The anti-bubble coating system for lithium battery pole piece coating of claim 6, wherein: The second period of time is 2 hours.

Description

Bubble-prevention coating system and method for coating lithium battery pole piece Technical Field The application relates to the technical field of battery manufacturing, in particular to an anti-bubble coating system and method for coating a lithium battery pole piece. Background In the process of coating the lithium ion battery pole piece, a slit extrusion type coating technology is widely applied. The slurry passes through a screw pump, a filter and a branch pipe, and is finally precisely coated on the current collector through a coating die head. However, a large amount of air is introduced into the entire closed slurry delivery system after each complete cleaning of the coating die, manifold, loading cart, screw pump or replacement of the main filter cartridge. This air is mixed into the slurry in the form of bubbles or "dead spots" that accumulate at the high points of the pipes, filters, valves, pump bodies, etc. In the related art, a "beating circulation" mode is generally adopted, that is, slurry is circulated between a feeding trolley and a coating die head, so as to try to take bubbles away by means of the slurry. However, the method has the inherent defects that new micro bubbles can be generated by cyclic shearing, the scouring force of the slurry in a laminar state is insufficient for static bubbles attached to the pipe wall or remained in dead angles, the slurry is difficult to be effectively sucked away, and in addition, the bubbles mixed into the slurry cannot be actively eliminated in the cyclic process. The direct consequence is that the slurry is uneven when the coating is started, the slurry contains bubbles, and the defect of 'metal leakage' is formed after the coating, so that the pole piece is scrapped, and the potential safety hazard of internal short circuit of the battery is buried. Disclosure of Invention The application provides an anti-bubble coating system and method for coating a lithium battery pole piece, which aims to reduce the scrapping condition of the pole piece, reduce the production cost and improve the quality of the battery pole piece. An embodiment of the present application provides, in a first aspect, an anti-bubble coating system for coating a lithium battery pole piece, including: the main coating system comprises a coating feeding tank, a screw pump, a filter and a coating die head, wherein one end of the screw pump is connected with a discharge hole of the coating feeding tank, the other end of the screw pump is connected with the coating die head, and the filter is arranged between the screw pump and the coating die head; The material receiving and refluxing unit comprises a material receiving funnel, a refluxing pipeline, a refluxing conveying pump, an auxiliary tank, a transferring pipeline and a transferring pump, wherein the material receiving funnel is arranged on one side of the coating die head, a feeding port of the material receiving funnel faces the coating die head, one end of the refluxing pipeline is connected with a discharging port of the material receiving funnel, the other end of the refluxing pipeline is connected with a feeding port of the auxiliary tank, the refluxing conveying pump is arranged on the refluxing pipeline, one end of the transferring pipeline is connected with a discharging port of the auxiliary tank, the other end of the transferring pipeline is connected with a feeding port of the coating feeding tank, the transferring pump is arranged on the transferring pipeline, a vacuum pump is connected to the auxiliary tank and used for enabling the internal pressure of the auxiliary tank to be under preset pressure. Optionally, a first filtering device is arranged between the backflow pipeline and the feed inlet of the auxiliary tank, and the first filtering device is used for performing primary filtering on the negative electrode slurry. Optionally, a second filtering device is arranged between the transfer pipeline and the feed inlet of the coating charging tank, and the second filtering device is used for filtering the recovered negative electrode slurry. Optionally, the material of the receiving funnel, the backflow pipeline and the transfer pipeline is stainless steel material. Optionally, the magnitude of the preset pressure is-0.08 MPa to-0.06 MPa. A second aspect of the embodiment of the present application provides an anti-bubble coating method for coating a lithium battery pole piece, which is applied to an anti-bubble coating system for coating a lithium battery pole piece according to the first aspect of the embodiment of the present application, and the method includes: Injecting negative electrode slurry into the coating feeding tank, and adjusting the discharge port of the coating die head to face the receiving hopper; Starting a main screw pump and a reflux conveying pump, enabling negative electrode slurry to sequentially flow through the main screw pump, a filter and a coating die head, enabling the negative ele