Extrusion coating head and coating machine thereof

Abstract

The invention relates to an extrusion coating head and a coating machine thereof. The extrusion coating head comprises an upper lip of an extrusion head and a lower lip of the extrusion head, wherein an extrusion passage is arranged between the upper lip of the extrusion head and the lower lip of the extrusion head, the extrusion passage is communicated with a storage cavity which is arranged in the lower lip of the extrusion head, a feeding passage and a return passage are also arranged in the lower lip of the extrusion head, and the feeding passage and the return passage are respectively communicated with the storage cavity; when the extrusion coating head is in coating, the return passage is closed, an upper extrusion surface which is arranged on the upper lip of the extrusion head in the extrusion passage can be inclined upwards, and air in the extrusion passage is discharged from a discharging opening of the extrusion passage along the upper extrusion surface. The air in the extrusion passage is discharged from the discharging opening of the extrusion passage, and the area of the cross section of the storage cavity is gradually reduced from middle part to two ends, so that a sizing agent is prevented from being blocked in the storage cavity; the discharging end of the lower lip of the extrusion head is provided with a protrusion part, so that the sizing agent is facilitated to be adhered onto a base material. The extrusion coating head and the coating machine thereof have the advantages of uniformity in coating, no exposure of foil, good coating effect, high production efficiency, high product quality and the like.

Description

technical field [0001] The present invention belongs to the technical field of substrate coating and manufacturing equipment for lithium-ion batteries, and in particular relates to an extrusion coating head and a coating machine thereof. Background technique [0002] In the production process of lithium-ion batteries, it is necessary to coat the prepared paste-like viscous slurry on the substrate evenly, continuously or intermittently, and ensure that the thickness of each coating position is consistent. At present, many manufacturers mainly use extrusion coating machines for coating. Extrusion coating machines mainly include a discharge mechanism, a coating head, a baking device and a material receiving mechanism, and there is a set on the upper lip of the coating head Return channel. When the extrusion coater is not coated, the slurry continuously entering the coating head flows out through the return channel, so that the slurry entering the coating head is always in a fl...

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Problems solved by technology

[0003] However, in the existing coating head of this structure, during the coating process, the return channel will be blocked, and there will be some fine air bubbles in the slurry. When the slurry enters the coating head, Under the action of gravity, these air bubbles will move upward and stay in the return channel located on the upper lip of the coating head. As the number of air bubbles increases, the air in the return channel will become more and more

Since the air in the return channel has expansion and contraction properties, and will exert a force on the slurry, it is difficult to control the amount of slurry flowing out from the outlet of the coating head, so that the coating on the substrate The slurry is unevenly coated, some places are thickly coated, some places are thinly coated, and even there will be exposed foil on the substrate, that is, the exposed part of the slurry on the coated substrate, and then Affect the coating quality and coating effect

[0004] Moreover, the cross-section of the existing material storage chamber arranged in the coating head is generally rectangular and "herringbone". The feeding channel of the coating head communicates with the middle part of the storage chamber. , the flow velocity of the slurry in the storage cavity is inversely proportional to the length of the storage cavity, so that the slurry flow velocity in the middle of the storage cavity is greater than the slurry flow velocity at both ends of the storage cavity, and the volume in the middle of the storage cavity It is as large as the volume at both ends, so the slurry can easily block the middle of the storage chamber, affecting the coating quality and coating effect

And in the existing coating head, the discharge end of the upper lip of the coating head is the same size as the discharge end of the lower lip of the coating head. When coating, due to the tension on the surface of the substrate, the coating Shrinkage holes will appear behind the cloth and exposed foil will appear on the substrate

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