A method and equipment for manufacturing lithium battery separator

Abstract

The present invention provides a preparation method and manufacturing equipment for a lithium battery separator, which improves production efficiency and reduces costs. A preparation method for a lithium battery separator includes a winding step, and the preparation method also includes a secondary traction step performed before the winding step, and the secondary traction step specifically includes: using one or more groups of heating rollers to traction the separator and heat the separator.

Description

Technical Field

[0001] The present invention belongs to the field of lithium battery diaphragm manufacturing, and specifically relates to a lithium battery diaphragm manufacturing method and manufacturing equipment, in particular to a secondary traction stress relief method and a secondary traction stress relief device. Background Art

[0002] During the production of diaphragms, due to the stress in the diaphragms, the diaphragms after winding need to be subjected to high temperature failure in order to prevent quality problems such as bridging and deformation. The high temperature failure time is usually 24 hours, and a large high temperature failure workshop is required. A lot of manpower and material resources are consumed during transportation and storage, affecting production efficiency and consuming a lot of energy. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide a method for preparing a lithium battery separator and a manufacturing device, which improves production efficiency and reduces costs.

[0004] In order to achieve the above object, a technical solution adopted by the present invention is:

[0005] A method for manufacturing a lithium battery separator includes a winding step. The method also includes a secondary traction step performed before the winding step. The secondary traction step specifically includes: using one or more groups of heating rollers to traction the separator and heat the separator.

[0006] Furthermore, in the secondary traction step, a pressing roller mechanism is used to press the diaphragm on the heating roller.

[0007] Furthermore, the secondary traction step also includes: using a cooling roller to cool the heated diaphragm, and using a pressing roller mechanism to press the diaphragm on the cooling roller.

[0008] Furthermore, the preparation method comprises the following steps performed in sequence: a primary stretching step, an extraction step, a secondary stretching step, the secondary traction step, and the winding step.

[0009] Another technical solution adopted by the present invention is:

[0010] A manufacturing device used in the preparation method as described above includes a secondary stretching device and a winding device, and also includes a secondary traction device arranged between the secondary stretching device and the winding device, the secondary traction device includes one or more heating rollers, and the heating rollers are provided with fluid channels for the circulation of heating medium.

[0011] Furthermore, the secondary traction device also includes a pressing roller mechanism for pressing the diaphragm, and the pressing roller mechanism includes at least two pressing rollers, the two pressing rollers are respectively conical or truncated cone-shaped, and the ends with smaller outer diameters of the two pressing rollers are arranged opposite to each other.

[0012] Furthermore, the pressing roller mechanism also includes a cylinder for driving the pressing roller to move to press the diaphragm.

[0013] Furthermore, the edge pressing roller is mounted on a mounting plate, the mounting plate is rotatably connected to a bracket, and the piston rod of the cylinder is rotatably connected to the mounting plate to drive the mounting plate to drive the edge pressing roller to move.

[0014] Furthermore, the secondary traction device also includes a cooling roller, and the number of the pressing roller mechanisms is multiple, and each of the heating rollers and the cooling rollers corresponds to one pressing roller mechanism respectively.

[0015] Furthermore, heat transfer oil flows through the fluid channel.

[0016] The present invention adopts the above technical solution, which has the following advantages compared with the prior art:

[0017] The diaphragm is heated by a heating roller through secondary traction, with a large heating area and a long heating time. The contact area between the heating roller and the diaphragm is large, the heating is uniform, and the internal stress elimination effect is good. It can eliminate the high-temperature failure link, increase production efficiency, and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0019] Figure 1 A flow chart of a method for preparing a lithium battery separator according to the present invention;

[0020] Figure 2 A schematic diagram of a lithium battery separator manufacturing device according to the present invention;

[0021] Figure 3 for Figure 2 A schematic diagram of the structure of the secondary traction device;

[0022] Figure 4 for Figure 2 A front view schematic diagram of the heating roller and the pressure roller mechanism;

[0023] Figure 5a ,5b They are Figure 4 A cross-sectional view of the two edge holding rollers;

[0024] Figure 6 for Figure 2 A side view of the heating roller and pressure roller mechanism in FIG.

[0025] Among them, 1. primary stretching device; 2. extraction device; 3. secondary stretching device; 4. secondary traction device; 5. winding device; 6. diaphragm;

[0026] 41. Heating roller; 42. Cooling roller; 43. Pressing roller mechanism; 431a. Edge pressing roller; 431b. Edge pressing roller; 432. Cylinder; 433. Pressing roller shaft; 434. Mounting plate; 435. Bracket. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art.

[0028] This embodiment provides a method for manufacturing a lithium battery separator, which includes a secondary traction step performed before the winding step, and the internal stress of the separator is removed by the secondary traction step. Figure 1 As shown, the manufacturing method includes the following steps performed in sequence: a primary stretching step, an extraction step, a secondary stretching step, the secondary traction step, and the winding step; in the primary stretching step, the diaphragm is longitudinally stretched, and in the secondary stretching step, the diaphragm is transversely stretched, wherein the diaphragm has been pulled before the secondary traction step, so the traction step after the secondary stretching is defined as the secondary stretching step for distinction. After the diaphragm is subjected to secondary traction to remove the internal stress, it is wound up through the winding step. After winding, the high-temperature failure treatment in the prior art may not be performed, that is, the effect of preventing the diaphragm from holding the tendons and deforming can be achieved; even if the high-temperature failure treatment is performed after winding, only a short high-temperature failure time is required. In the secondary traction step, the internal stress of the diaphragm is removed by heating the diaphragm with a heating roller.

[0029] This embodiment also provides a lithium battery separator manufacturing device, referring to Figure 2 As shown, the manufacturing equipment comprises a primary stretching device 1, an extraction device 2, a secondary stretching device 3, a secondary traction device 4 and a winding device 5 which are arranged in sequence. The secondary traction device 4 arranged between the secondary stretching device 3 and the winding device 5 is used to perform the above-mentioned secondary traction step.

[0030] Figure 3 FIG. 4 shows a secondary traction device 4 used in this embodiment. Figure 3As shown, the secondary traction device 4 includes one or more heating rollers 41, cooling rollers 42 and a pressure roller mechanism 43. The heating roller 41 is provided with a fluid channel for the circulation of a heating medium, and the diaphragm 6 is heated by the heat carried by the heating medium. The heating medium is preferably heat-conducting oil. Specifically in this embodiment, the number of heating rollers 41 is five, and they are staggered up and down. The number of cooling rollers 42 is one, and it is arranged on the rear side of the heating roller 41. The diaphragm 6 is secondary pulled by the above-mentioned five heating rollers 41 and one cooling roller 42, and the diaphragm 6 is first heated and then cooled. The pressure roller mechanism 43 is used to press the diaphragm 6 against the heating roller 41 or the cooling roller 42 to prevent the diaphragm 6 from shrinking and deforming laterally. Preferably, the number of the pressure roller mechanism 43 is multiple, and each of the heating rollers 41 and the cooling roller 42 corresponds to one pressure roller mechanism 43.

[0031] Reference Figure 4 As shown, each pressing roller mechanism 43 includes at least two pressing rollers 431a and 431b. The pressing rollers 431a and 431b are fixedly arranged on a pressing roller shaft 433 (such as fixed by bolts, etc.), and the pressing roller shaft 433 is rotatably connected to a bracket 435 around its own axis.

[0032] Reference Figure 5a and Figure 5b As shown, the two edge pressing rollers 431a and 431b are respectively in the shape of a cone or a truncated cone, and the ends of the two edge pressing rollers 431a and 431b with smaller outer diameters are arranged opposite to each other. That is, the outer diameter of the outer end of the edge pressing rollers 431a and 431b is greater than the outer diameter of the inner end. The "outer end" of the edge pressing roller specifically refers to the end farther from the other edge pressing roller, and the "inner end" specifically refers to the end closer to the other edge pressing roller. The roller surface of the edge pressing rollers 431a and 431b is a rubber layer, or the edge pressing rollers 431a and 431b are rubber rollers as a whole.

[0033] Reference Figure 4 and Figure 6As shown, each pressing roller mechanism 43 also includes a cylinder 432 for driving the pressing rollers 431a and 431b to move to press the diaphragm. The pressing rollers 431a and 431b are connected to the mounting plate 434, and the mounting plate 434 is rotatably connected to the bracket 435. The piston rod of the cylinder 432 is rotatably connected to the mounting plate 434 to drive the mounting plate 434 to drive the rollers to move. Specifically, one end of the mounting plate 434 is rotatably connected to the bracket 435, and the end of the pressing roller shaft 433 is rotatably connected to the other end of the mounting plate 434 around its own axis, specifically through a bearing connection, the piston rod of the cylinder 432 is rotatably connected between the two ends of the mounting plate 434, and the cylinder body of the cylinder 432 is movably connected to the bracket 435. As the piston rod of the air cylinder 432 extends, the mounting plate 434 rotates, and the pressing roller shaft 433 moves toward the heating roller 41 or the cooling roller 42. The edge pressing rollers 431a and 431b on the pressing roller shaft 433 (moving to Figure 6 The position indicated by the middle dotted line) further presses the diaphragm against the heating roller 41 or the cooling roller 42.

[0034] In the above preparation method, the secondary traction step is specifically carried out as follows: Figure 3-6 The secondary traction device shown performs secondary traction on the diaphragm to remove the internal stress. The specific process is: firstly, the diaphragm is pulled and heated by one or more sets of heating rollers 41, and the diaphragm on the heating roller 41 is pressed by the pressing roller mechanism 43; then, the heated diaphragm is cooled by the cooling roller 42, and the diaphragm on the cooling roller 42 is pressed by the pressing roller mechanism 43; the treated diaphragm is rolled up through a rolling up step.

[0035] The manufacturing method and manufacturing equipment of the present invention have the following characteristics: the diaphragm is heated by multiple heating rollers 41 through secondary traction, with a large heating area and a long heating time. After heating, it is cooled by the last cooling roller 42 to remove the internal stress of the diaphragm; a pressing roller mechanism 43 is added to the heating roller 41 and the cooling roller 42 to prevent the diaphragm from shrinking and deforming during heating and cooling; the two pressing rollers 431a and 431b are conical or truncated cone-shaped, that is, the roller surface is slightly inclined, so that the film surface is smoother and wrinkling and deformation are effectively prevented; the position of the pressing rollers 431a and 431b can be adjusted according to the width of the film surface; the pressing roller mechanism 43 uses a cylinder 432 as a motion actuator, and the pressure of the pressing rollers 431a and 431b can be adjusted by air pressure.

[0036] In the present invention, the high-temperature failure link can be eliminated, production efficiency can be increased, and energy consumption can be reduced; the multiple heating rollers 41 have a large contact area with the diaphragm, are heated evenly, and have a good effect in eliminating internal stress; the use of the above-mentioned new pressure roller mechanism 43 can not only avoid the quality problems caused by the lateral shrinkage of the diaphragm, but also effectively prevent the pressure roller from causing scratches on the surface of the diaphragm.

[0037] The above embodiment is only for illustrating the technical concept and features of the present invention, and is a preferred embodiment. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention.

Claims

1. A manufacturing device for a lithium battery separator, comprising a secondary stretching device and a winding device, characterized in that: The manufacturing equipment includes a primary stretching device for longitudinally stretching the diaphragm, and the secondary stretching device is located behind the primary stretching device to transversely stretch the diaphragm; The manufacturing equipment further comprises a secondary traction device disposed between the secondary stretching device and the winding device, wherein the secondary traction device is configured to remove the internal stress of the diaphragm after the secondary stretching to avoid high temperature failure treatment of the diaphragm; The secondary traction device comprises one or more heating rollers, wherein the heating rollers are provided with fluid channels for the circulation of the heating medium; the secondary traction device also comprises a pressing roller mechanism for pressing the diaphragm, wherein the pressing roller mechanism comprises at least two pressing rollers, wherein the pressing rollers are respectively in the shape of a cone or a truncated cone, and the ends of the two pressing rollers with smaller outer diameters are arranged opposite to each other; The pressing roller mechanism also includes a cylinder for driving the pressing roller to move to press the diaphragm; The edge holding roller is connected to a mounting plate, the mounting plate is rotatably connected to a bracket, and the piston rod of the cylinder is rotatably connected to the mounting plate to drive the mounting plate to drive the edge holding roller to move; The edge pressing roller is fixedly arranged on the pressure roller shaft. As the piston rod of the cylinder extends, the mounting plate rotates, and the pressure roller shaft approaches the heating roller accordingly. The edge pressing roller on the pressure roller shaft then presses the diaphragm onto the heating roller. The heating roller pulls the diaphragm from the secondary stretching device and heats the diaphragm. The diaphragm is first longitudinally stretched by the primary stretching device, then transversely stretched by the secondary stretching device, and finally rolled up by the winding device after the internal stress is removed by the secondary pulling device.

2. The manufacturing equipment for lithium battery separator according to claim 1, characterized in that: The secondary traction device also includes a cooling roller. The number of the pressing roller mechanisms is multiple, and each of the heating rollers and the cooling rollers corresponds to one pressing roller mechanism.

3. The manufacturing equipment for lithium battery separator according to claim 1, characterized in that: Heat transfer oil flows through the fluid channel.

4. A method for manufacturing a lithium battery separator, comprising a winding step, characterized in that: Using the manufacturing equipment as described in any one of claims 1-3; The manufacturing method comprises a primary stretching step, an extraction step, a secondary stretching step, a secondary pulling step and a winding step which are performed sequentially. The diaphragm is longitudinally stretched in the primary stretching step, transversely stretched in the secondary stretching step, and then the internal stress is removed in the secondary pulling step before finally being wound up in the winding step. The secondary pulling step specifically comprises: using one or more groups of heating rollers to pull the diaphragm and heat the diaphragm.

5. The manufacturing method according to claim 4, characterized in that: In the secondary traction step, a pressing roller mechanism is used to press the diaphragm on the heating roller.

6. The manufacturing method according to claim 4, characterized in that: The secondary traction step also includes: cooling the heated diaphragm with a cooling roller, and pressing the diaphragm on the cooling roller with a pressing roller mechanism.

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