A coating device with flow distribution structure

Abstract

The present invention relates to a coating device with a flow distribution structure, comprising a coating die head, wherein the coating die head has an upper template and a lower template, and at least two levels of coating chambers connected to each other are arranged between the upper template and the lower template, wherein the first coating chamber is connected to a feed port located in the middle of the feed side, and the discharge coating chamber is located on the upper side of the lower template and is connected to a row of coating film area channels toward the discharge end. The coating device can reduce the adjustment frequency and amplitude of the flow block and the push-pull rod, which is very beneficial to the coating process of the new coating die head, and can greatly reduce the waste of resources and time.

Description

Technical Field

[0001] The invention relates to a coating device with a flow distribution structure. Background Art

[0002] Lithium batteries are currently the secondary battery products with the best performance. There is much room for improvement in energy density, power density, life, environmental adaptability, safety and cost. Lithium-ion power batteries are the basis of application technologies and engineering technologies such as hybrid vehicles, pure electric vehicles and energy storage systems.

[0003] The pole piece manufacturing process is the basic process for manufacturing lithium batteries. This link has very high requirements on the accuracy, reliability and scientific design of the equipment used. Common pole piece manufacturing processes include transfer type and slit extrusion type. Studies have shown that the transfer type coating window is relatively narrow, the process parameter range is small, and the slurry is easy to absorb moisture and introduce impurities during the coating process, which is prone to various defects and poor consistency.

[0004] Slit extrusion coating refers to a process in which a certain flow of slurry enters the internal cavity of the die from the feed port of the extrusion head and forms a stable pressure. The slurry is finally ejected from the slit outlet of the die and coated on the foil. The key indicator of coating is the uniformity of the coating surface density, which is mainly determined by the distribution of the lip flow of the coater die. The existing slit coater mainly consists of a die body (upper and lower dies), a baffle and a push-pull rod (flow regulating structure) and other accessories. The lateral flow distribution of the lip is mainly adjusted by the baffle and the push-pull rod. However, when the coater starts coating, due to the large difference (extreme difference) in the lateral weight distribution of the coating, it is difficult to adjust the baffle and the push-pull rod, and the adjustment time is increased, resulting in a waste of resources.

[0005] The closest existing technical solution (CN103025439B) is a fluid distribution system.

[0006] In the current slot extrusion coating die, the slurry enters from the feed port and first enters the mixing cavity to achieve lateral distribution of the slurry in the cavity, then flows through the slit channel to the die lip, forms a coating film under the action of the backing rod and is taken away. Due to the uneven lateral weight distribution of the coating, the current slot coating die generally sets a flow block between the mixing cavity and the lip to adjust the flow distribution, and sets a push-pull rod structure to adjust the flow by adjusting the deformation of the lip.

[0007] However, the current problem with the lateral flow distribution adjustment of the coating die is that the flow and pressure distribution in the mixing chamber are uneven, and the difference (extreme difference) between the maximum and minimum values ​​in the lateral position of the coating is large, which often exceeds the adjustment capacity of the baffle and the push-pull rod, or requires frequent adjustments and longer time to achieve the desired effect, which will waste more resources and time. Summary of the invention

[0008] The object of the present invention is to provide a coating device with a flow distribution structure, which can uniformly extrude a plurality of strip-shaped coating material sheets, thereby facilitating high-efficiency production.

[0009] The present invention includes a coating die head, which has an upper template and a lower template. At least two levels of coating cavities connected to each other are arranged between the upper and lower templates, wherein the first coating cavity is connected to a feed port located in the middle of the feed side, and the discharge coating cavity is located on the upper side of the lower template and is connected to a row of coating film area channels toward the discharge end.

[0010] Furthermore, a sealing gasket is arranged between the upper and lower templates, and the sealing gasket is provided with a hollow notch communicating with the upper side of the discharge coating cavity and cooperates with the upper and lower templates to form a coating film area channel.

[0011] Furthermore, the connected coating chambers are located at the upper part of the lower template, and connecting throttling channels are evenly distributed along the length direction between two adjacent coating chambers, and the connecting throttling channels are composed of hollow connecting parts of the sealing gasket located between the upper and lower templates.

[0012] Furthermore, the sealing gasket is composed of a whole sheet located between the upper and lower templates, and the sheet is provided with bolt through-holes, hollow connecting parts and hollow notches correspondingly.

[0013] Furthermore, the first coating chamber is a distribution chamber, the discharge coating chamber is a mixing chamber, and the connecting throttling channel is a distribution channel.

[0014] Furthermore, the hollow notch is in the shape of a rectangular strip.

[0015] Furthermore, the upper template, the lower template and the sealing gasket are connected by connecting bolts which are arranged at intervals and penetrate the upper template.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The slurry of the coating device first enters the distribution chamber with a smaller volume from the feed port, and then enters the mixing chamber through distribution channels with different numbers, positions and sizes. The slurry flow and pressure are evenly distributed in the mixing chamber (if uneven, the number, position and size of the distribution channels can be adjusted). The evenly distributed slurry passes through the slit channels of the same size to form a uniform coating film on the lip. The adjustment frequency and amplitude of the flow block and the push-pull rod can be reduced, which is very beneficial to the coating process of the new coating die head and can greatly reduce the waste of resources and time.

[0018] 2. Solve the problems of large coating weight range (lateral weight distribution) and "N" weight and "U" weight in the coating process of lithium battery electrodes; improve the coating uniformity at the beginning of the coating process of lithium battery electrodes. Among them, range: the difference between the maximum and minimum values ​​of the slurry weight distribution in the coating width direction after the slurry is coated on the pole piece; N weight: after the slurry is coated on the pole piece, the slurry weight in the coating width direction presents the shape of "large in the middle and small on both sides" (N type); U weight: after the slurry is coated on the pole piece, the slurry weight in the coating width direction presents the shape of "small in the middle and large on both sides" (U type).

[0019] 3. The coating device can evenly extrude multiple strips of coating material sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a coating die head of the present invention;

[0021] Figure 2 It is a schematic diagram of the fluid domain structure formed by the upper mold, the lower mold and the gasket of the present invention;

[0022] Figure 3 The coating effect of the present invention is compared with that of the prior art solution;

[0023] In the figure: 10 - coating die head 11 - feed port 12 - mixing chamber 13 - distribution chamber 14 - distribution channel 15 - upper template 16 - lower template 17 - sealing gasket 18 - connecting bolt 19 - coating film area channel 20 - hollow notch 21 - hollow connecting part 22 - bolt through-hole. DETAILED DESCRIPTION

[0024] In order to make the above features and advantages of the present invention more understandable, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0025] refer to Figures 1 to 3

[0026] A coating device with a flow distribution structure includes a coating die head 10, wherein the coating die head has an upper template and a lower template, and at least two levels of coating chambers connected to each other are arranged between the upper and lower templates, wherein the first coating chamber 13 is connected to the feed port 11 located in the middle of the feed side, and the discharge coating chamber is located on the upper side of the lower template and is connected to a row of coating film area channels 19 toward the discharge end. The first coating chamber is a distribution chamber 13, and the discharge coating chamber is a mixing chamber 12, so that the slurry is distributed to the mixing chamber, and the slurry is mixed again through the mixing chamber.

[0027] In this embodiment, the output port of the discharge end is a coating lip, so that the slurry can be coated through the coating lip.

[0028] In this embodiment, in order to better form the coating film area channel and reduce the processing difficulty, a sealing gasket 17 is provided between the upper and lower templates. The sealing gasket is composed of a whole sheet located between the upper and lower templates, and the sheet is provided with a bolt through-hole 22, a hollow connecting portion 21 and a hollow notch 20. The upper side of the discharge coating cavity is connected to the hollow notch 20 of the sealing gasket, and the hollow notch cooperates with the upper and lower templates to form the coating film area channel 19.

[0029] In this embodiment, the interconnected coating chambers are located at the upper part of the lower template. At the same time, in order to connect the coating chambers, connecting throttling channels are evenly distributed along the length direction between two adjacent coating chambers, and the connecting throttling channels constitute distribution channels 14, so that the slurry entering the distribution chamber is distributed to the mixing chamber through the connecting throttling channels.

[0030] In this embodiment, in order to better form a connecting throttling channel, the connecting throttling channel is composed of a hollow connecting portion 21 of a sealing gasket located between the upper and lower templates, thereby enabling the slurry in the distribution chamber to be delivered into the mixing chamber.

[0031] In this embodiment, the sheet is made of rigid material to ensure strength and service life.

[0032] In this embodiment, in order to more evenly coat the slurry, the coating film area channel is a slit channel.

[0033] In this embodiment, in order to better form the coating film area channel and achieve uniform coating, the hollow slots are rectangular strips with the same size.

[0034] In this embodiment, in order to achieve connection and fixation of the upper mold, the lower mold and the sealing gasket, the upper mold, the lower mold and the sealing gasket are connected by connecting bolts 18 that are arranged at intervals and penetrate the upper mold and the sealing gasket.

[0035] In this embodiment, the volume of the distribution chamber is smaller than that of the mixing chamber; other channels are also provided on the sealing gasket.

[0036] When the device is used, after the slurry enters from the feed port, it first enters the distribution chamber with a smaller volume before entering the mixing chamber, and performs a lateral distribution of pressure and flow. Distribution channels of different numbers, positions and sizes are set between the distribution chamber and the mixing chamber. After the slurry enters the mixing chamber through the distribution channel, the slurry in the mixing chamber is evenly distributed in the lateral position (the slurry flow and pressure in the mixing chamber are evenly distributed. If not, the number, position and size of the distribution channels can be adjusted). Then the evenly distributed slurry flows to the lip through the slit channel (coating film area channel) of the same size to form a uniform coating film. The coating film formed at this time has a smaller range of coating lateral weight and a more uniform distribution when no other adjustments are made. The device can reduce the adjustment frequency and amplitude of the baffle block and the push-pull rod, which is very beneficial to the coating process of the new coating die head and can greatly reduce the waste of resources and time.

[0037] When this coating device is used, the flow distribution (speed) of the lip in the coating width direction is as follows: Figure 3 As shown, initial is the technical solution of the existing die head. It can be seen that the flow rate difference of the die head lip is relatively large in the coating width direction. Figure 3 G-0, G-1, G-2, and G-3 are the results of four structures when using the coating device. The only difference between these four structures is the size and position of the distribution channel. It can be seen that when the G-2 and G-3 structures in the new technology solution are adopted, the lip flow rate in the coating width direction is more consistent than that of the existing coating structure.

[0038] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A coating device with a flow distribution structure, comprising a coating die head, characterized in that: The coating die head comprises an upper template and a lower template, and at least two levels of coating chambers connected to each other are arranged between the upper template and the lower template, wherein the first coating chamber is connected to the feed port located in the middle of the feed side, and the discharge coating chamber is located on the upper side of the lower template and is connected to a row of coating film area channels toward the discharge end; the connected coating chambers are located on the upper part of the lower template, and connecting throttling channels are evenly distributed between two adjacent coating chambers along the length direction, and the connecting throttling channels are composed of a hollow connecting part of a sealing gasket located between the upper and lower templates; the first coating chamber is a distribution chamber and has a smaller volume than the mixing chamber, the discharge coating chamber is a mixing chamber, and the connecting throttling channel is a distribution channel.

2. A coating device with a flow distribution structure according to claim 1, characterized in that: A sealing gasket is arranged between the upper and lower templates. The sealing gasket is provided with a hollow notch communicating with the upper side of the discharge coating cavity and cooperates with the upper and lower templates to form a coating film area channel.

3. A coating device with a flow distribution structure according to claim 2, characterized in that: The sealing gasket is composed of a whole piece of sheet material located between the upper and lower templates, and a bolt through hole is correspondingly opened on the sheet material.

4. A coating device with a flow distribution structure according to claim 2 or 3, characterized in that: The hollow notch is in the shape of a rectangular strip.

5. A coating device with a flow distribution structure according to claim 1, 2 or 3, characterized in that: The upper template, the lower template and the sealing gasket are connected by connecting bolts which are arranged at intervals and penetrate the upper template.

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