Extrusion die head assembly of extrusion coating machine

Abstract

The present invention relates to an extrusion die assembly of an extrusion coating machine, comprising a cavity upper structural part and a cavity lower structural part, characterized in that the surface of the cavity lower structural part is provided with a groove, the cavity upper structural part is located at the top of the groove to enclose the groove into a cavity, and the cavity is a hollow cavity with a simulated cone streamline structure; the cavity lower structural part is provided with a feed port connected to the cavity, a die head gasket is provided between the cavity upper structural part and the cavity lower structural part, the gap formed by the die head gasket between the cavity upper structural part and the cavity lower structural part is the discharge port of the cavity, the feed port is located at the bottom of the cavity, and the discharge port is located at the top of the cavity; the cavity upper structural part is provided with a guide tube. The hollow cavity with a simulated cone streamline structure makes the slurry flow conform to the characteristics of fluid mechanics, the flow rate is more stable, and the extrusion is more uniform.

Description

Technical Field

[0001] The invention relates to the field of production coating processing equipment for lithium ion batteries, in particular to an extrusion die head assembly of an extrusion coating machine. Background Art

[0002] Nowadays, countries around the world are vigorously developing green and efficient secondary energy. As a new type of secondary battery, lithium-ion batteries have the advantages of high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and green environmental protection. They have broad application prospects in portable appliances, power tools, large energy storage, and electric transportation power sources. The coating process is one of the key processes in the manufacturing process of lithium-ion batteries. The consistency of the coating directly affects the electrochemical performance and safety performance of the battery. The extrusion coater has the advantages of high efficiency, good coating consistency, and smooth appearance, and has become the mainstream trend of the current coating process technology.

[0003] The application of lithium-ion battery extrusion coating machine technology is becoming more and more widespread. Extrusion coating has higher coating speed and precision, and the closed system of extrusion coating is conducive to the stability of coating slurry characteristics, free from pollution, and significantly reduces the impact of the environmental system on the coating slurry. The existing extrusion coating device includes a feeding device, a return device, a valve, an extrusion die head and a gasket. The extrusion coating device has higher requirements for the slurry delivery method and quality. The cavity pressure cannot fluctuate during the process, otherwise it will affect the consistency of the longitudinal surface density, and impurities, bubbles and particle agglomerates cannot be generated. If the feed rate is unstable during the coating process, it is easy to cause large differences in the surface density of the pole piece, which directly affects the safety performance and capacity consistency of the battery.

[0004] In the prior art, CN201721807943.0 discloses an extrusion coating machine, including a die head, the die head including an upper die head and a lower die head and a die head gasket disposed between the upper die head and the lower die head, the die head gasket is U-shaped, the enclosed area between the two arms is a feed cavity, the opening is a discharge port, the bottom surface of the feed cavity is convex to one side of the discharge port, so that the middle of the feed cavity is narrower than the two sides. The machine is designed to have a die head gasket that is convex to the bottom surface of the feed cavity on one side of the discharge port, so that the middle of the feed cavity is narrower than the two sides, so that the speed distribution of the slurry in the die head is relatively uniform, the speed of the slurry discharged from the discharge port is uniform, and the coating plane is uniform during extrusion coating, thereby ensuring the consistency of the battery capacity and helping to improve the overall performance of the battery.

[0005] For example, CN202022524101.2 discloses an extrusion coated rubber gasket, including an extrusion coated rubber gasket, including a gasket body, a first guide groove arranged in the gasket body, and a second guide groove arranged on the gasket body; the first guide groove includes a first guide groove outlet arranged on one side of the first guide groove and a first guide groove arranged on both sides of the first guide groove outlet; the second guide groove includes a connecting rib arranged in the second guide groove, a second guide groove arranged at one end of the second guide groove, and a second guide groove outlet arranged at one end of the second guide groove.

[0006] However, the existing extrusion die heads have dead corners due to their structural characteristics. During the long-term use of the slurry, the local area in the die cavity becomes the dead corner of the slurry. The slurry in the dead corner does not have fluidity, which can easily lead to gelation or even agglomeration of the slurry in the dead corner over time. The instability of the slurry will cause the longitudinal surface density of continuous coating to be unqualified and the peak clipping of the coating gap to be unstable.

[0007] Therefore, how to provide an effective die head assembly for use in a coating machine to eliminate slurry dead corners, improve the fluidity of the slurry in the mold cavity, and further improve the coating effect is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0008] The purpose of the present invention is to solve the defects of the prior art and provide an extrusion die head assembly for an extrusion coating machine.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] An extrusion die assembly of an extrusion coating machine comprises an upper cavity structural part and a lower cavity structural part, wherein the surface of the lower cavity structural part is provided with a groove, the upper cavity structural part is located at the top of the groove to enclose the groove to form a cavity, and the cavity is a hollow cavity with a simulated cone streamline structure; the lower cavity structural part is provided with a feed port connected to the cavity, a die head gasket is provided between the upper cavity structural part and the lower cavity structural part, a gap formed by the die head gasket between the upper cavity structural part and the lower cavity structural part is the discharge port of the cavity, the feed port is located at the bottom of the cavity, and the discharge port is located at the top of the cavity; a flow guide tube is provided on the upper cavity structural part.

[0011] Furthermore, the mold cavity is filled with a left filling block, an upper filling block, a lower filling block and a right filling block. The top-view cross-section of the cavity after the left filling block and the right filling block are assembled is a gyroscope-like shape, and the top-view cross-sections of the upper filling block and the lower filling block are gyroscope-like shapes; the left filling block, the upper filling block, the lower filling block and the right filling block are combined into a hollow slurry mold cavity with a cone-like structure.

[0012] Further, the die head gasket is provided with a first alignment station and a second alignment station at both sides of the discharge port, the opposing surfaces of the left filling block and the right filling block are both arc-shaped, a third alignment station is provided at the end of the arc-shaped surface of the left filling block, a fourth alignment station is provided at the end of the arc-shaped surface of the right filling block, both side surfaces of the upper filling block and the lower filling block are arc-shaped, a fifth alignment station and a sixth alignment station are respectively provided at the ends of the arc-shaped surface on both sides of the upper filling block, and a seventh alignment station and an eighth alignment station are respectively provided at the ends of the arc-shaped surface on both sides of the lower filling block;

[0013] When the left filling block, the upper filling block, the lower filling block and the right filling block are filled in the mold cavity, the first alignment station, the third alignment station, the fifth alignment station and the seventh alignment station are aligned, and the second alignment station, the fourth alignment station, the sixth alignment station and the eighth alignment station are aligned.

[0014] Furthermore, a first guide pipe groove is provided on the left filling block, and a second guide pipe groove is provided on the right filling block. The first guide pipe groove and the second guide pipe groove are connected to the guide pipe, and the first guide pipe groove and the second guide pipe groove are used to conduct the reflowing slurry.

[0015] Furthermore, the upper filling block is fitted with the upper structural part of the mold cavity, and the lower filling block is fitted with the lower structural part of the mold cavity.

[0016] Furthermore, the left filling block and the right filling block are symmetrically installed on both sides of the mold cavity.

[0017] The beneficial effects of the present invention are as follows: 1. The hollow mold cavity with a cone-like streamline structure formed by the filling blocks of the component and the streamlined structure of the contact surface between the filling blocks and the slurry make the slurry flow conform to the fluid mechanics characteristics, the flow rate is more stable, and the extrusion is more uniform, so that the fluid pressure in the middle of the lip of the die head outlet and the edge of the coating is stable during coating, the speed distribution of the slurry extruded from the slit is uniform, the thickness of the coated film surface and the edge is consistent, the coating edge thickness and the range of the abnormal area of ​​the coating edge can be more effectively controlled, multiple continuous coatings can be achieved, and the utilization rate of the equipment is improved.

[0018] 2. The combined filling blocks of this component fill all the dead corners in the mold cavity, so that during coating production, there is no slurry remaining in the mold cavity for too long, which improves the problems of gelation, agglomeration and sedimentation caused by too long retention of slurry, and the slurry fluidity is more stable.

[0019] 3. The material of the filling block is metal, inorganic non-metallic material, organic polymer material and other materials, which can be replaced according to the coating model. Changing the model is more convenient and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a left side cross-sectional schematic diagram of the extrusion die head of the present invention after a filling block is placed in the die cavity;

[0021] Figure 2 It is a top cross-sectional schematic diagram of the assembled left and right filling blocks of the present invention;

[0022] Figure 3 It is a schematic diagram of the cross section of the mold cavity from the left side of the present invention;

[0023] Figure 4 It is a schematic diagram of a top-view cross-section of a gyroscope-like body after a filling block is filled in the mold cavity of the present invention;

[0024] Figure 5 It is a top cross-sectional schematic diagram of the die head gasket of the present invention;

[0025] Figure 6 It is a schematic diagram of a top cross-section of the mold cavity of the present invention;

[0026] Figure 7 It is a top cross-sectional schematic diagram of an upper filling block of the present invention;

[0027] Figure 8 It is a top cross-sectional schematic diagram of the lower filling block of the present invention;

[0028] Fig. 9 It is a coating schematic diagram of the present invention. DETAILED DESCRIPTION

[0029] like Figures 1 to 8 As shown, an extrusion die assembly of an extrusion coating machine includes an upper cavity structure 1 and a lower cavity structure 2, wherein the surface of the lower cavity structure 2 is provided with a groove, wherein the upper cavity structure 1 is located at the top of the groove to enclose the groove into a cavity 5, and the lower cavity structure 2 is provided with a feed port 3 connected to the cavity 5, and a die head gasket 6 is provided between the upper cavity structure 1 and the lower cavity structure 2, and a gap formed by the die head gasket 6 between the upper cavity structure 1 and the lower cavity structure 2 is a discharge port 4 of the cavity 5, and a guide tube 11 is provided on the upper cavity structure 1, and the cavity 5 is filled with a left filling block 9, an upper filling block 7, a lower filling block 8 and a right filling block 10; wherein the upper filling block 7 is fitted with the upper cavity structure 1, and the lower filling block 8 is fitted with the lower cavity structure 2.

[0030] The left filling block 9 and the right filling block 10 are symmetrically installed on both sides of the mold cavity 5. The material of the mold cavity upper part structure 1 and the mold cavity lower part structure 2 is stainless steel.

[0031] The left filling block 9, the upper filling block 7, the lower filling block 8 and the right filling block 10 are made of metal, inorganic non-metallic material or organic polymer material, the feed port 3 is located at the bottom of the mold cavity 5, and the discharge port 4 is located at the top of the mold cavity 5. The left filling block 9, the upper filling block 7, the lower filling block 8 and the right filling block 10 are preferably made of corrosion-resistant organic silicone material.

[0032] The die head gasket 6 is provided with a first alignment station 14 and a second alignment station 15 at both sides of the discharge port 4 (see Figure 5 ), the opposing surfaces of the left filling block 9 and the right filling block 10 are both arc-shaped (see Figure 2 ), a third alignment station 16 is provided at the end of the arc surface of the left filling block 9, and a fourth alignment station 17 is provided at the end of the arc surface of the right filling block 10 (see Figure 2 ), both sides of the upper filling block 7 and the lower filling block 8 are arc-shaped surfaces (see Figure 1 ), the fifth alignment station 18 and the sixth alignment station 19 are respectively provided at the ends of the arcuate surfaces on both sides of the upper filling block 7 (see Figure 7 ), the arc-shaped end portions on both sides of the lower filling block 8 are respectively provided with a seventh alignment station 20 and an eighth alignment station 21 (see Figure 8 ).

[0033] When the left filling block 9, the upper filling block 7, the lower filling block 8 and the right filling block 10 are filled in the mold cavity 5, the first alignment station 14, the third alignment station 16, the fifth alignment station 18 and the seventh alignment station 20 are aligned, and the second alignment station 15, the fourth alignment station 17, the sixth alignment station 19 and the eighth alignment station 21 are aligned.

[0034] A first guide pipe groove 12 is provided on the left filling block 9, and a second guide pipe groove 13 is provided on the right filling block 10. The first guide pipe groove 12 and the second guide pipe groove 13 are connected to the guide pipe 11, and the first guide pipe groove 12 and the second guide pipe groove 13 are used to conduct the reflowing slurry.

[0035] During installation, the upper filling block 7 fits tightly together with the upper structural part 1 of the mold cavity, the lower filling block 8 fits tightly together with the lower structural part 2 of the mold cavity, the left filling block 9, the upper filling block 7, the lower filling block 8 and the right filling block 10 are combined into a hollow cone-like streamline structure, and the hollow cavity is the slurry mold cavity; during installation, the first guide pipe groove 12 and the second guide pipe groove 13 are connected to the guide pipe 11, and the guide pipe 11 is connected to the slurry return device.

[0036] After the die assembly is assembled, the electrode slurry is injected into the slurry cavity according to the requirements of the coating process, the process parameters are adjusted, and the slurry is coated. The characterization of the coating parameters is as follows: Fig. 9As shown, measure the thickness of the head, middle and tail of the coated pole piece and record it in Table 1; measure the thickness of the left, middle and right of the same horizontal position of the coated pole piece and record it in Table 1; measure the thickness of the left, middle and right of the same horizontal position of the peak clipping position of the head of the coated pole piece and record it in Table 1;

[0037] Observation of slurry stability in slurry mold cavity:

[0038] After assembling the die assembly, inject the electrode slurry into the slurry cavity according to the requirements of the coating site process, adjust the process parameters, and coat the slurry. Record the status of the slurry in areas 7, 8, 9, and 10 in the slurry cavity at the beginning of coating, 12 hours after production, and 24 hours after production, and record them in Table 2.

[0039] Comparative Example:

[0040] Die head installation:

[0041] See also Figure 1-8 An extrusion coating machine die head assembly is provided, in which the left filling block 9, the upper filling block 7, the lower filling block 8 and the right filling block 10 are not provided in the comparative example.

[0042] It includes a cavity upper structural component 1, a cavity lower structural component 2, and a die head gasket 6. The structural components 1 and 2 and the die head gasket 6 are made of metal stainless steel; the structural component 2 has a concave semi-cylindrical structure, the structural components 1 and 2 form a hollow structure, the gasket 6 is installed at the middle connecting portion of the structural components 1 and 2, a feed port 3 is installed in the middle of the arc surface of the lower structural component 2, the feed port 3 is connected to an external feeding device, a discharge port 4 is installed on the gasket 6, the discharge port 4 has a lip, and when installed, the guide pipe 11 is connected to the slurry return device.

[0043] Battery slurry coating:

[0044] After the die assembly is assembled, the electrode slurry is injected into the mold cavity according to the requirements of the coating process, the process parameters are adjusted, and the slurry is coated. The characterization of the coating parameters is as follows: Fig. 9 As shown, measure the thickness of the head, middle and tail of the coated pole piece, and record it in Table 1; measure the thickness of the left, middle and right of the same horizontal position of the coated pole piece, and record it in Table 1; measure the thickness of the left, middle and right of the same horizontal position of the peak clipping position of the head of the coated pole piece, and record it in Table 1;

[0045] Observation of slurry stability in the mold cavity:

[0046] After assembling the die assembly, inject the electrode slurry into the mold cavity according to the requirements of the coating site process, adjust the process parameters, and coat the slurry. Record the status of the slurry in areas 7, 8, 9, and 10 in the mold cavity at the beginning of coating, 12 hours after production, and 24 hours after production, and record them in Table 2.

[0047] Table 1: Thickness record table of different coating positions

[0048] Table 2: Observation record of slurry stability in the mold cavity

[0049]

[0050] From the data in Table 1 and Table 2, it can be seen that the thickness of the pole piece coated by the die assembly is consistent, and the thickness of the pole piece at different positions has almost no change after 24 hours, and the slurry has no gel or agglomeration. However, the thickness of the pole piece coated by the die head as a comparative example fluctuates at 12 hours of production, and the slurry in the mold cavity also has gel and even agglomeration.

[0051] Because the design dimensions of lithium-ion batteries can vary greatly, the coating width also changes during coating production. Therefore, in actual operation, the coating width is achieved by adjusting the width of the die head gasket, which easily leads to the appearance of left and right dead angles in the die cavity during coating production. At the same time, the semi-cylindrical structure of the original die cavity will also lead to the appearance of dead angles in the upper and lower areas of the cavity.

[0052] The hollow mold cavity with a cone-like streamlined structure formed by the filling blocks of the present embodiment and the streamlined structure of the contact surface between the filling blocks and the slurry ensure that there are no dead angles in the mold cavity, and the slurry flow conforms to the characteristics of fluid mechanics, so that the fluid pressure in the middle of the lip of the die head outlet and the edge of the coating is stable during coating, the flow rate is more stable, the speed distribution of the slurry squeezed out from the lip slit is uniform, the extrusion is more uniform, the coated film surface and edge thickness are consistent, the coating edge thickness and the range of abnormal areas of the coating edge can be more effectively controlled, multiple continuous coatings can be achieved, and the utilization rate of the equipment is improved.

[0053] The combined filling blocks of the components of this embodiment fill up all the dead corners in the mold cavity, so that during coating production, there is no slurry remaining in the mold cavity for too long, which improves the problems of gelation, agglomeration and sedimentation caused by too long retention of slurry, and the slurry fluidity is more stable.

[0054] The existing die head is a full metal structure, and the price is extremely high. If each lithium-ion battery model uses a corresponding full metal die head, the die head cost investment is huge and it is easy to cause material waste. The present invention creatively proposes a low-cost filling block structure design, and can design filling blocks of different sizes according to different models produced. At the same time, the material of the filling block can be selected from low-cost and easy-to-process metals, inorganic non-metallic materials, organic polymer materials, etc., and can be easily replaced according to the coated model. The filling block has strong adaptability and low cost.

[0055] Those skilled in the art should understand that the device of the present invention is not limited to the embodiments described in the specific implementation manner, and the above specific description is only for the purpose of explaining the present invention, and is not used to limit the present invention. Those skilled in the art can derive other implementations based on the technical solution of the present invention, which also belong to the technical innovation scope of the present invention, and the protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. An extrusion die assembly for an extrusion coating machine, comprising an upper cavity structure (1) and a lower cavity structure (2), characterized in that: The surface of the mold cavity lower part structural member (2) is provided with a groove, the mold cavity upper part structural member (1) is located at the top of the groove to enclose the groove to form a mold cavity (5), and the mold cavity (5) is a hollow mold cavity with a conical streamline structure; the mold cavity lower part structural member (2) is provided with a feed port (3) connected to the mold cavity (5), a die head gasket (6) is provided between the mold cavity upper part structural member (1) and the mold cavity lower part structural member (2), and the gap formed by the die head gasket (6) between the mold cavity upper part structural member (1) and the mold cavity lower part structural member (2) is the discharge port (4) of the mold cavity (5), the feed port (3) is located at the bottom of the mold cavity (5), and the discharge port (4) is located at the top of the mold cavity (5); the mold cavity upper part structural member (1) is provided with a guide tube (11); The mold cavity (5) is filled with a left filling block (9), an upper filling block (7), a lower filling block (8) and a right filling block (10); the top-view cross-section of the cavity after the left filling block (9) and the right filling block (10) are assembled is a gyroscope-like shape; the top-view cross-sections of the upper filling block (7) and the lower filling block (8) are gyroscope-like shapes; the left filling block (9), the upper filling block (7), the lower filling block (8) and the right filling block (10) are combined to form a hollow slurry mold cavity with a conical streamline structure; The upper filling block (7) is fitted with the upper structural member (1) of the mold cavity, and the lower filling block (8) is fitted with the lower structural member (2) of the mold cavity; The left filling block (9) and the right filling block (10) are symmetrically installed on both sides of the mold cavity (5).

2. The extrusion die assembly of an extrusion coating machine according to claim 1, characterized in that: The die head gasket (6) is provided with a first alignment station (14) and a second alignment station (15) at both sides of the discharge port (4); the opposing surfaces of the left filling block (9) and the right filling block (10) are both arc-shaped; a third alignment station (16) is provided at the end of the arc-shaped surface of the left filling block (9); a fourth alignment station (17) is provided at the end of the arc-shaped surface of the right filling block (10); both side surfaces of the upper filling block (7) and the lower filling block (8) are arc-shaped; a fifth alignment station (18) and a sixth alignment station (19) are provided at the ends of the arc-shaped surface of the upper filling block (7); and a seventh alignment station (20) and an eighth alignment station (21) are provided at the ends of the arc-shaped surface of the lower filling block (8); When the left filling block (9), the upper filling block (7), the lower filling block (8) and the right filling block (10) are filled in the mold cavity (5), the first alignment station (14), the third alignment station (16), the fifth alignment station (18) and the seventh alignment station (20) are aligned, and the second alignment station (15), the fourth alignment station (17), the sixth alignment station (19) and the eighth alignment station (21) are aligned.

3. The extrusion die assembly of an extrusion coating machine according to claim 1, characterized in that: The left filling block (9) is provided with a first guide pipe groove (12), and the right filling block (10) is provided with a second guide pipe groove (13), the first guide pipe groove (12) and the second guide pipe groove (13) being connected to the guide pipe (11), and the first guide pipe groove (12) and the second guide pipe groove (13) being used to guide the reflowing slurry.

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