Process adjusting method for improving base film edge collapse deformation at coating end

Abstract

The invention relates to the technical field of battery diaphragms, and particularly discloses a process adjustment method for improving edge collapse deformation of a base membrane at a coating end. A process adjusting method for improving edge collapse and deformation of a base film at a coating end comprises the following steps: S1, unwinding: placing the edge collapse and deformation base film in an unwinding system for unwinding, controlling the unwinding tension to be 10-30N, and controlling the wind frequency of an unwinding traction adsorption roller to be 20-50Hz; s2, conveying: conveying the unreeled base film through a plurality of passing rollers to reach a flattening roller; s3, flattening and preheating: flattening the base film by a flattening roller, controlling the angle of the flattening roller to be 10-50 degrees, conveying the base film into a preheating drying oven system, controlling the temperature of the drying oven to be 30-70 DEG C, and heating and ironing; and S4, unwinding and traction are conducted, specifically, the heated and ironed base film is conveyed to an unwinding and traction adsorption roller through a roller. According to the method, the defects of edge collapse and deformation of the base film can be overcome.

Description

Technical Field

[0001] The present application relates to the technical field of battery separators, and more specifically, to a process adjustment method for improving the edge collapse deformation of a base film at a coating end. Background Art

[0002] Lithium-ion batteries are currently widely used in electric vehicles. As a separator, it has a great impact on the safety performance of batteries and has an irreplaceable position in lithium batteries. Battery separators can be divided into dry film making and wet film making according to the process path. At present, most of the preparation processes of battery separators on the market are mainly based on wet film. However, wet film is more prone to collapse and deformation during the manufacturing process due to uneven thickness and incomplete stress release. This type of separator has collapsed edges and deformation in appearance, which will cause the coating film to pass through the coating head during the manufacturing process, causing defects such as missing coating, creases, and wrinkles, thereby affecting the coating yield. Therefore, the preparation process of wet film needs to be improved. Summary of the invention

[0003] In order to reduce the occurrence of collapse and deformation of the battery base film, the present application provides a process adjustment method for improving the collapse and deformation of the base film at the coating end, using the following technical solution:

[0004] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0005] S1, unwinding: Place the collapsed and deformed base film in the unwinding system for unwinding, control the unwinding tension to 10-30N, and the wind frequency of the unwinding traction adsorption roller to 20-50Hz;

[0006] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller;

[0007] S3, flattening and preheating: the flattening roller flattens the base film, controls the angle of the flattening roller to be 10-50°, and conveys it to the preheating oven system, the oven temperature is controlled at 30-70°C, and heats and irons it;

[0008] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0009] By adopting the above technical solution, the present application adjusts the parameters of the base film coating process, optimizes the unwinding tension, the flattening roller angle, the wind frequency of the unwinding traction adsorption roller, and the preheating oven temperature, so as to reduce the proportion of base film creases and oblique wrinkles, and reduce the proportion of base film collapse and deformation, so that the base film has better flatness and improves the coating yield. The main function of the adsorption roller is to separate the tension system and realize the segmented control of the tension system.

[0010] Optionally, the collapsed edge and deformed area of ​​the collapsed edge and deformed base film is ≤50%.

[0011] By adopting the above technical solution, when the collapsed edge and deformation area of ​​the base film are ≤50%, the collapsed edge and deformation problems of the base film can be effectively improved through the adjustment method of the present application, so that the base film has a smoother appearance.

[0012] Optionally, the collapsed and deformed base film is selected from a dry-process diaphragm or a wet-process diaphragm.

[0013] By adopting the above technical solution, the adjustment method of the present application can adjust both dry-process diaphragms and wet-process diaphragms, that is, the adjustment method of the present application has a wider scope of application.

[0014] Optionally, the width of the collapsed and deformed base film is 100-1300 mm.

[0015] By adopting the above technical solution, the width of the base film is optimized. At an appropriate width, the base film can be conveyed by the unwinding system, flattened by the flattening roller, and heated and ironed in the preheating oven. In the coating process, creases and oblique wrinkles are not likely to occur again, which is conducive to obtaining better flatness of the base film.

[0016] Optionally, the thickness of the collapsed and deformed base film is 3-20 μm.

[0017] By adopting the above technical solution, the thickness of the base film is optimized. At an appropriate thickness, the base film can be fully flattened by the flattening roller and ironed under heating, which is conducive to the base film obtaining better flatness.

[0018] Optionally, the roller coating thickness of the collapsed and deformed base film is 0.5-5 μm.

[0019] Optionally, the flattening roller in step S3 may be a curved flattening roller.

[0020] Optionally, the heating structure in the preheating oven in step S3 may be a heat-conducting roller.

[0021] Optionally, the adsorption roller in step S4 may be a pressure roller.

[0022] Optionally, it can be applied to any one of polymer coating films, ceramic coating films, and organic / inorganic hybrid coating films.

[0023] By adopting the above technical solution, the adjustment method of the present application can be applied to any coating film including polymer coating films, ceramic coating films, and organic / inorganic hybrid coating films, and the application of the adjustment method of the present application is relatively wide.

[0024] In summary, this application has the following beneficial effects:

[0025] 1. This application adjusts the parameters of the base film coating process, optimizes the unwinding tension, flattening roller angle, unwinding traction adsorption roller wind frequency and preheating oven temperature, so as to reduce the proportion of base film creases and oblique wrinkles, reduce the proportion of base film collapse and deformation, so that the base film has better flatness and improves the coating yield.

[0026] 2. The present application optimizes the case where the collapsed edge and deformation area of ​​the base film are ≤50%. Through the adjustment method of the present application, the collapsed edge and deformation problems of the base film can be effectively improved, so that the base film has a smoother appearance.

[0027] 3. The present application optimizes the width of the base film. At an appropriate width, the base film can be conveyed by the unwinding system, flattened by the flattening roller, and ironed by the preheating oven. It is not easy to generate creases, oblique wrinkles, etc. again during the coating process, which is conducive to the base film to obtain better flatness. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the method provided by this application.

[0029] Description of the drawings: 1. Unwinding system; 2. Flattening roller; 3. Preheating oven system; 4. Traction adsorption system. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] Example

[0032] Example 1

[0033] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0034] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 10N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0035] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0036] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0037] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0038] Example 2

[0039] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0040] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0041] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0042] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0043] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0044] Example 3

[0045] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0046] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 30N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0047] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0048] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0049] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0050] Example 4

[0051] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0052] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0053] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0054] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 10°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0055] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0056] Example 5

[0057] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0058] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0059] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0060] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 50°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0061] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0062] Example 6

[0063] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0064] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 20Hz;

[0065] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0066] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0067] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0068] Example 7

[0069] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0070] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 50Hz;

[0071] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0072] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0073] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0074] Example 8

[0075] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0076] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0077] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0078] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 30°C, and heats and irons it;

[0079] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0080] Example 9

[0081] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0082] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0083] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0084] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and transports it to the preheating oven system 3, controls the oven temperature to be 70°C, and heats and irons it;

[0085] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0086] Comparative Example

[0087] Comparative Example 1

[0088] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0089] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 8N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0090] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0091] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0092] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0093] Comparative Example 2

[0094] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0095] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 32N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0096] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0097] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0098] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0099] Comparative Example 3

[0100] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0101] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0102] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0103] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 8°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0104] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0105] Comparative Example 4

[0106] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0107] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0108] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0109] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 52°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0110] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0111] Comparative Example 5

[0112] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0113] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 18Hz;

[0114] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0115] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 50°C, and heats and irons it;

[0116] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0117] Comparative Example 6

[0118] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0119] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0120] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0121] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 28°C, and heats and irons it;

[0122] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0123] Comparative Example 7

[0124] The present application provides a process adjustment method for improving the edge collapse deformation of a base film at a coating end, comprising the following steps:

[0125] S1, unwinding: select a base film with a width of 1020mm, a thickness of 9um, and a collapse deformation of 50%, place the base film in the unwinding system 1 for unwinding, control the unwinding tension to 20N, and the wind frequency of the unwinding traction adsorption roller to 35Hz;

[0126] S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller 2;

[0127] S3, flattening and preheating: the flattening roller 2 flattens the base film, controls the angle of the flattening roller 2 to be 35°, and conveys it to the preheating oven system 3, controls the oven temperature to be 72°C, and heats and irons it;

[0128] S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

[0129] Table 1

[0130]

[0131]

[0132] Performance testing

[0133] (1) Test the treated base film for MD thermal shrinkage (the standard is to heat the test at 120°C for 1 hour).

[0134] Table 2 Performance test

[0135]

[0136]

[0137] Combining the performance test comparison in Table 2, we can find that:

[0138] 1. It can be seen from Table 1 and Table 2 that the base films with the same specifications of collapsed edge and deformed areas are selected for verification. The collapsed edge deformation of the base film at the coating unwinding end after adjustment in Examples 1 to 9 of the present application is greatly improved, about 95% of the collapsed edge and deformed base film are improved, the base film produces creases, the oblique wrinkles are controlled within 1-9%, the MD heat shrinkage rate is controlled within 1, and the collapsed edge and deformation defects of the base film are greatly improved.

[0139] 2. It can be seen from Table 1 and Table 2 that base films with the same specifications of collapsed edge and deformed areas are selected for verification. In comparative examples 1 to 7, when the unwinding tension, the flattening roller angle, the wind frequency of the unwinding traction adsorption roller, and the preheating oven temperature are not within the scope of this application, the collapsed edge deformation of the base film at the unwinding end cannot be improved well, resulting in creases and a high proportion of oblique wrinkles, especially when the preheating oven temperature reaches 72°C, the MD thermal shrinkage rate reaches 1.52, and assembling it inside the battery poses a great safety hazard.

[0140] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A process adjustment method for improving the edge collapse deformation of the base film at the coating end, characterized in that: The following steps are involved: S1, unwinding: placing the collapsed and deformed base film in the unwinding system (1) for unwinding, controlling the unwinding tension to be 10-30N, and the wind frequency of the unwinding traction adsorption roller to be 20-50Hz; S2, conveying: the unrolled base film is conveyed through several rollers and reaches the flattening roller (2); S3, flattening and preheating: the flattening roller (2) flattens the base film, the angle of the flattening roller (2) is controlled to be 10-50°, and the base film is transported to the preheating oven system (3), the oven temperature is controlled to be 30-70°C, and the base film is heated and ironed; S4, unwinding and traction: the heated and ironed base film is transferred to the unwinding and traction adsorption roller through the roller.

2. A process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The collapsed edge and deformed area of ​​the collapsed edge and deformed base film is ≤50%.

3. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The edge-collapsed and deformed base film is selected from a dry-process diaphragm or a wet-process diaphragm.

4. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The width of the collapsed and deformed base film is 100-1300 mm.

5. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The thickness of the collapsed and deformed base film is 3-20 μm.

6. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The roller coating thickness of the collapsed and deformed base film is 0.5-5 μm.

7. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The flattening roller (2) in step S3 may be a curved flattening roller (2).

8. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: The heating structure in the preheating oven in step S3 may be a heat-conducting roller.

9. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: In the step S4, the adsorption roller may be a pressure roller.

10. The process adjustment method for improving the edge collapse deformation of the base film at the coating end according to claim 1, characterized in that: It can be applied to any coating film including polymer coating film, ceramic coating film and organic / inorganic mixed coating film.

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