High-magnification stretching and shaping integrated device

Abstract

The invention relates to the technical field of forming equipment, and discloses a high-magnification stretching and shaping integrated device which comprises an equipment main body, and a heat treatment chamber, a stretching and shaping chamber and a heating assembly are arranged on the equipment main body. The device is provided with the heat treatment chamber, heat treatment is firstly carried out on the casting base film, crystal area defects are eliminated, the lamellar structure is further perfected, and the crystallinity of the film is improved. Then the prepared polypropylene casting base film is stretched at low temperature through a low-temperature chamber of a stretching chamber to form microdefects such as crazing, and then the defects are pulled open through high-temperature stretching and extension of a high-temperature chamber to form micropores. And in the stretching process, stretching in the length direction and extrusion extension with different gap sizes in the width direction are carried out at the same time, so that an ultrahigh pore diameter and stable pore diameter distribution and porosity can be obtained, the uniformity of micropore distribution in the stretching and shaping process is ensured, and the high-functionality diaphragm meeting the requirement is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of forming equipment, and in particular to a high-ratio stretching and shaping integrated device. Background Art

[0002] While traditional liquid lithium batteries offer high ionic conductivity, their liquid electrolytes have a low boiling point and are prone to leakage, which can easily lead to the growth of lithium dendrites. This results in relatively low energy density and safety concerns. Solid-state electrolytes offer a promising opportunity to address safety concerns and prevent the growth of lithium dendrites, but they suffer from poor interfacial stability, high interfacial impedance, complex production processes, and high manufacturing costs, making large-scale commercial applications difficult. Semi-solid-state batteries offer superior performance to liquid batteries but inferior to all-solid-state batteries. However, they offer improved safety, higher energy density, longer cycle life, a wider operating temperature range, and are resistant to extrusion and vibration. Consequently, they have found widespread application.

[0003] Currently, semi-solid battery separators are primarily made of wet-process polyolefin films coated with ceramic materials. This coating improves the separator's heat resistance and puncture resistance, enhancing battery safety. However, these separators suffer from significant interface resistance between the battery electrode and the separator, and relatively low lithium-ion conductivity, requiring further improvement.

[0004] SUMMARY OF THE INVENTION

[0005] The technical problem solved by the present invention is that the existing semi-solid battery separator has defects such as large interface contact impedance between the battery electrode and the separator and relatively low lithium ion conductivity.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A high-ratio stretching and shaping integrated device, comprising:

[0008] Equipment body;

[0009] A stretching and shaping chamber is provided with a plurality of forming roller groups, wherein the forming roller groups include a plurality of forming rollers rotatably arranged on the equipment body, and the forming rollers are grouped in pairs, with a forming gap formed between the two forming rollers in the same group;

[0010] A heating component, the heating component is used to heat the stretching and shaping chamber;

[0011] Wherein, the stretching and shaping chamber includes a stretching chamber and a shaping chamber;

[0012] In the stretching chamber, the gap between the roller groups is set to gradually decrease from the stretching starting end to the stretching output end to the product size; the forming gap between the forming roller groups in the same group includes an initial end and an end end, and the gap size at the initial end is smaller than the gap size at the end end.

[0013] In one embodiment of the present invention, the temperature in the shaping chamber gradually decreases from the feed end to the discharge end.

[0014] In one embodiment of the present invention, a heat treatment chamber is provided on the equipment body, and the heat treatment chamber is provided at the front end of the stretching and shaping chamber.

[0015] In one embodiment of the present invention, the stretching chamber includes a low-temperature chamber and a high-temperature chamber.

[0016] In one embodiment of the present invention, the initial end is arranged at one end of the forming roller.

[0017] In one embodiment of the present invention, the initial end is arranged at the middle of the forming roller, and the terminal end is arranged at both ends of the forming roller.

[0018] In one embodiment of the present invention, the gap size at the initial end of the stretching start end is consistent with the initial size of the diaphragm entering the stretching chamber.

[0019] In one embodiment of the present invention, a concave-convex structure is provided at a position corresponding to the initial end of the forming roller.

[0020] In one embodiment of the present invention, two adjacent chambers are separated by a partition with a notch.

[0021] Beneficial effects of the present invention:

[0022] This device is used to perform stretching and shaping processing on the diaphragm to obtain the required battery diaphragm with ultra-high pore size, stable pore size distribution and porosity. This device is equipped with a heat treatment chamber. First, the cast base film is heat-treated to eliminate crystal defects, further improve the lamellae structure, and increase the crystallinity of the film. Then, the prepared polypropylene cast base film is stretched at a low temperature in the low-temperature chamber of the stretching chamber to form micro-defects such as silver streaks, and then the defects are stretched and extended at high temperature in the high-temperature chamber to form micropores. In the stretching process, by simultaneously stretching in the length direction and extrusion and extension with different gap sizes in the width direction, ultra-high pore size, stable pore size distribution and porosity can be obtained, and the uniformity of the micropore distribution in the stretching and shaping process is ensured to prepare a diaphragm that meets the requirements of high functionality.

[0023] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 It is a schematic structural diagram of the present invention as a whole;

[0026] Figure 2 This is a schematic structural diagram of an embodiment of a forming roller of the present invention;

[0027] Figure 3 It is a structural schematic diagram of another embodiment of the forming roller of the present invention;

[0028] Figure 4 It is a structural schematic diagram of the concave-convex structure of the present invention.

[0029] The reference numerals in the figure are: 1. Equipment body; 2. Forming roller group; 3. Heat treatment chamber; 4. Concave-convex structure. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0032] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0033] See also Figure 1-4 The present invention is a high-ratio stretching and shaping integrated device, comprising an equipment body 1, wherein the equipment body 1 is used to support, fix and provide an installation position, and the main frame is used to install and set the various components of the device. The equipment body 1 is provided with a heat treatment chamber 3, a stretching and shaping chamber and a heating assembly. The heat treatment chamber 3 is provided at the front end of the device, i.e., the feed end. The cast base film is heat-treated by the heat treatment chamber 3 to eliminate crystal defects, further improve the lamellar structure, and improve the crystallinity of the film.

[0034] See also Figure 1-4In one embodiment of the present invention, a plurality of forming roller groups 2 are disposed within the stretching and shaping chamber. The forming roller groups 2 include a plurality of forming rollers rotatably disposed at corresponding positions within the main body 1 of the apparatus. The forming rollers are grouped in pairs, with a forming gap formed between the two forming rollers in the same group. The stretching and shaping chamber comprises a stretching chamber and a shaping chamber, each comprising a low-temperature chamber and a high-temperature chamber. In the low-temperature chamber of the stretching chamber, the prepared polypropylene cast base film is first stretched at a low temperature (e.g., 0-20°C) to form micro-defects such as silver streaks. The defects are then stretched open at a high temperature (e.g., 80-120°C) in the high-temperature chamber to form micropores. The roller group within the shaping chamber serves as the shaping roller group, with one end of the shaping chamber closest to the stretching chamber serving as the feed end and the other end as the discharge end. The temperature gradually decreases from the feed end to the discharge end, thereby gradually cooling and shaping the diaphragm and ensuring uniform and stable micropore formation.

[0035] See also Figure 1-4 In one embodiment of the present invention, in the stretching chamber, one end close to the heat treatment chamber 3 is used as the stretching starting end, and the other end is the stretching output end. The gap between the roller groups is set to gradually decrease from the stretching starting end to the stretching output end, and the gap between the roller groups at the starting end and the gap at the output end is gradually reduced to the product size. This gradually promotes the gradual extension and molding of the diaphragm product. The forming gap between the forming roller groups 2 in the same group includes an initial end and an end end, and the gap size at the initial end is smaller than the gap size at the end end. The initial end can be set at one end (such as Figure 2 ), or it can be set in the middle and the ends at both ends (such as Figure 3 The end with the smaller gap at the starting end of stretching can be used as the initial end of feeding. The gap size there (the section corresponding to the section entering the diaphragm) can be consistent with the initial size of the diaphragm entering the stretching chamber. In this way, under the action of several roller groups, the diaphragm can be gradually stretched from one end to the other to increase the width size, ensuring the uniformity of the diaphragm extension. The stretching in the length direction and the stretching in the width direction work together to ensure that ultra-high pore size and stable pore size distribution and porosity are obtained during the diaphragm forming process.

[0036] See also Figure 1-4 In one embodiment of the present invention, a concave-convex structure 4 may be provided at the position corresponding to the initial end of the forming roller, thereby forming a boundary line on the diaphragm product and ensuring the position stability of the diaphragm product during the extension process in the width direction of the diaphragm.

[0037] See also Figure 1-4In one embodiment of the present invention, a heating component is provided on the main body 1 of the device, and the heating component is used to heat and increase the temperature of the stretching and shaping chamber, and can also be used to supply heat to the heat treatment chamber 3 at the same time. The heating component can pass a heat medium such as steam into the stretching and shaping chamber for heating. A heat exchange channel can also be provided in the forming roller to heat the forming roller. Electric heating can also be used, such as providing an electric heating wire in the side wall of the stretching and shaping chamber or in the forming roller as a heat source. The two adjacent chambers can be separated by a partition with a notch (for the passage of the diaphragm), and a transition chamber can be further provided for transition to reduce the temperature influence of the adjacent chambers. The roller group in the transition chamber serves as a separation roller group to ensure the heat insulation effect (for the chambers on both sides).

[0038] Working principle of the present invention:

[0039] At present, semi-solid battery separators are mainly made of wet-process polyolefin films coated with ceramic materials. The coating of ceramic materials improves the heat resistance of the separator, enhances the puncture resistance of the separator, and improves the safety of battery use. However, there are defects such as large interface contact impedance between the battery electrode and the separator and relatively low lithium ion conductivity, which need to be further improved. In this application, cyclopentane sulfone is used to dissolve thermoplastic polyimide, and lithium bis(trifluoromethanesulfonyl)imide and fast ion conductor lithium lanthanum zirconium oxide are introduced into the solution, and stirred to obtain a spray liquid. The polypropylene base film is corona treated on both sides, then sprayed and dried to obtain a gel polyimide composite separator. The gel polyimide coating greatly improves the heat resistance of the separator and improves the safety of the lithium battery. The gel polyimide is in close contact with the electrode, which greatly reduces the interface impedance and reduces the amount of liquid electrolyte added during the preparation of the lithium battery, meeting the preparation requirements of the semi-solid battery. The fast ion conductor lithium lanthanum zirconium oxide is introduced into the gel polyimide to increase the ionic conductivity of the electrolyte, improve the charging speed of the lithium battery, and hinder the growth of lithium dendrites. While improving the safety and charging efficiency of semi-solid-state batteries, the battery charging speed and energy density can also be further increased. In this solution, a battery separator with large pore size, high porosity and high strength is required.

[0040] This device is used to stretch and shape the diaphragm to obtain the required battery diaphragm with ultra-high pore size, stable pore size distribution and porosity. This device is provided with a heat treatment chamber 3. First, the cast base film is heat-treated to eliminate crystal defects, further improve the lamellae structure, and improve the crystallinity of the film. Then, the prepared polypropylene cast base film is stretched at a low temperature through the low-temperature chamber of the stretching chamber to form micro-defects such as silver streaks, and then the defects are stretched and extended through high-temperature stretching and extension in the high-temperature chamber to form micropores. In the stretching process, by stretching in the length direction and extrusion and extension with different gap sizes in the width direction at the same time, ultra-high pore size, stable pore size distribution and porosity can be obtained, and the uniformity of the micropore distribution in the stretching and shaping process is ensured to prepare a diaphragm that meets the requirements of high functionality.

[0041] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A high-ratio stretching and shaping integrated device, characterized in that: include: Device body (1); A stretching and shaping chamber, wherein a plurality of shaping roller groups (2) are arranged in the stretching and shaping chamber, wherein the shaping roller groups (2) include a plurality of shaping rollers rotatably arranged on the equipment body (1), wherein the shaping rollers are arranged in groups of two, and a shaping gap is formed between two shaping rollers in the same group; A heating component, the heating component is used to heat the stretching and shaping chamber; Wherein, the stretching and shaping chamber includes a stretching chamber and a shaping chamber; In the stretching chamber, the gap between the roller groups is arranged to gradually decrease from the stretching starting end to the stretching output end to the product size; the forming gap between the forming roller groups (2) in the same group includes an initial end and an end, and the gap size at the initial end is smaller than the gap size at the end; In the shaping chamber, the temperature gradually decreases from the feeding end to the discharging end.

2. A high-ratio stretching and shaping integrated device according to claim 1, characterized in that: A heat treatment chamber (3) is provided on the equipment body (1), and the heat treatment chamber (3) is arranged at the front end of the stretching and shaping chamber.

3. A high-ratio stretching and shaping integrated device according to claim 1, characterized in that: The stretching chamber includes a low temperature chamber and a high temperature chamber.

4. The high-ratio stretching and shaping integrated device according to claim 1, characterized in that: The initial end is arranged at the end of the forming roller.

5. The high-ratio stretching and shaping integrated device according to claim 1, characterized in that: The initial end is arranged at the middle of the forming roller, and the terminal end is arranged at both ends of the forming roller.

6. The high-ratio stretching and shaping integrated device according to claim 1, characterized in that: The gap size at the initial end of the stretching start end is consistent with the initial size of the diaphragm entering the stretching chamber.

7. The high-ratio stretching and shaping integrated device according to claim 1, characterized in that: A concave-convex structure (4) is arranged at a position corresponding to the initial end of the forming roller.

8. The high-ratio stretching and shaping integrated device according to claim 1, characterized in that: Two adjacent chambers are separated by a partition with a notch.

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