Flattening device for coating pole piece of lithium ion battery

Abstract

The utility model provides a flattening device for coating a pole piece of a lithium ion battery, which is characterized in that a bulge structure is adopted, an annular bulge is arranged in the middle of an extension roller corresponding to a coating blank area, and threaded bulges are symmetrically distributed on the left and right sides of the annular bulge; when in use, the positions of the annular bulges of the extension rollers correspond to the coated blank areas, so that the wrinkled foil in the middle blank area after being taken out of a drying oven can be effectively expanded and shaped, and the blank area is stretched to be in an arc-shaped state, so that the wrinkling condition of the blank area is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field related to lithium ion battery manufacturing, and particularly relates to a flattening device for coating pole pieces of lithium ion batteries. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] During the lithium-ion battery manufacturing process, coated electrodes undergo a compaction process. For multiple coated electrodes, blank areas are left in the middle and on both sides of the coating, and the tabs are placed in the blank areas on both sides.

[0004] Existing technologies primarily use a forward and backward pulling method for stretching, failing to extend the blank area. This results in wrinkles and unevenness at the intersection of the coating area and the blank area, and even leads to broken strips. This is especially true for negative electrode copper foil. With the rapid development of lithium-ion batteries in recent years, competition in battery cost and performance has become increasingly fierce. Reducing the thickness of the current collector and saving internal battery space has gradually become a key research direction for battery developers. Therefore, thinning copper foil has become particularly important, and manufacturers have gradually reduced the thickness of the copper foil current collector from 6μm to 4.5μm to save battery thickness space.

[0005] As the thickness of the copper foil current collector gradually becomes thinner, there are still major problems with the processing performance of copper foil in actual applications. The most prominent problem is that after the negative electrode is coated and taken out of the oven, there is a high risk of wrinkles in the blank areas in the middle and on both sides of the coating area, especially in the blank area in the middle of multiple coatings. The thickness of the coating area and the blank area causes the stress difference in the baking and pulling process to be unable to be released in time, and the risk of wrinkles is even higher. If the wrinkles are not flattened before rolling, the processing difficulty of subsequent rolling, slitting and other processes will be greatly increased, and the negative electrode may even have to be scrapped. Utility Model Content

[0006] In order to solve the above problems, the utility model proposes a flattening device for lithium-ion battery coated electrodes, which can effectively expand and shape the wrinkled foil in the middle blank area after leaving the oven, stretching the blank area into an arc state to avoid wrinkles in the blank area.

[0007] According to some embodiments, the utility model adopts the following technical solution: a flattening device for coating pole pieces of lithium-ion batteries, comprising an extension roller and a correction roller, the extension roller being provided with an annular protrusion and a threaded protrusion, the threaded protrusion being symmetrically arranged on both sides of the annular protrusion.

[0008] Furthermore, a plurality of raised particle points are provided on the thread-shaped protrusion.

[0009] Furthermore, the raised particle points are arranged at equal intervals.

[0010] Furthermore, a plurality of the extension rollers are arranged along the belt running direction.

[0011] Furthermore, the height of the annular protrusion of the stretching roller decreases along the belt running direction.

[0012] Furthermore, a first extension roller, a second extension roller and a third extension roller are arranged in sequence along the walking direction; the height of the annular protrusion on the second extension roller is 1 / 3 of the height of the annular protrusion on the first extension roller; the height of the annular protrusion on the third extension roller is 1 / 3 of the height of the annular protrusion on the second extension roller.

[0013] Furthermore, the angle of the thread-shaped protrusion perpendicular to the foil running direction is 5° to 30°.

[0014] Furthermore, the position of the annular protrusion corresponds to the coating blank position area.

[0015] Furthermore, the width of the annular protrusion is 3 mm to 4 mm.

[0016] Furthermore, the raised particle points are arc-shaped.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This embodiment adopts a raised structural setting, in which an annular protrusion is set on the extension roller, and the annular protrusion has thread-shaped protrusions symmetrically distributed on the left and right sides; when in use, the annular protrusion of the extension roller is positioned corresponding to the coating blank area, which can effectively expand and shape the wrinkled foil in the middle blank area after leaving the oven, stretching the blank area into an arc state, and avoiding the occurrence of wrinkles in the blank area. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0020] Figure 1 It is an overall schematic diagram of an existing flattening device;

[0021] Figure 2 This is an overall schematic diagram of the flattening device in the utility model;

[0022] Figure 3 This is a schematic diagram of the structure of a single extension roller in the utility model;

[0023] Figure 4 This is a schematic diagram of the coating film area in the utility model;

[0024] Figure 5This is a schematic diagram of the positions of multiple extension rollers in the present invention;

[0025] Figure 6 This is another schematic diagram of the positions of multiple extension rollers in the present invention;

[0026] In the figure, 1. annular protrusion, 2. thread-shaped protrusion, 3. raised arc-shaped particle point, 4. oven outlet, 5. first extending roller, 6. second extending roller, 7. third extending roller, 8. extending roller, 9. deviation correction roller, 10. pole piece. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0029] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational terms determined merely for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention. In the present invention, terms such as "fixed connection", "connected", "connected" and the like should be understood in a broad sense, indicating that they can be fixedly connected, integrally connected or detachably connected; they can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meanings of the above terms in the present invention according to specific circumstances, and they cannot be understood as limitations on the present invention.

[0030] Example 1

[0031] like Figure 2 and Figure 3 As shown, a flattening device for coating electrodes of lithium-ion batteries includes an extension roller and a correction roller. The extension roller is provided with an annular protrusion 1 and a threaded protrusion 2. The threaded protrusion 2 is symmetrically arranged on both sides of the annular protrusion 1.

[0032] Compared with the existing stretching rollers that use concave stripes, this embodiment adopts a raised structure setting, and an annular protrusion 1 is provided in the middle of the stretching roller corresponding to the coating blank area, and the annular protrusion 1 has thread-shaped protrusions 2 symmetrically distributed on the left and right; the annular protrusion 1 is provided in the middle of the stretching roller corresponding to the coating blank area, which can effectively expand and shape the wrinkled foil in the middle blank area after leaving the oven, stretch the blank area into an arc state, and avoid the occurrence of wrinkles in the blank area.

[0033] The existing solution is usually to add an extension roller after the coating area exits the oven outlet 4, and then connect the correction roller 9 after the extension roller 8. After passing the correction roller 9 and other rollers, the coating film is wound up. Figure 2 In this embodiment, the coating film passes through three stretching rollers 8 after leaving the oven, and then passes through the stretching rollers 8 and the correction rollers 9, and then passes through the correction rollers 9 and other rollers to roll up the coating film.

[0034] It should be noted that the number of the stretching rollers 8 is not limited to three and can be set accordingly according to actual needs.

[0035] See also Figure 3 , a plurality of raised particle points are provided on the thread-shaped protrusion 2; specifically, the raised particle points are arc-shaped raised particle points 3, and the arc-shaped raised particle points 3 are evenly spaced on the thread-shaped protrusion 2. The provision of the arc-shaped raised particle points 3 can increase the friction during the extension process.

[0036] See also Figure 5 and Figure 6 A plurality of extension rollers are arranged along the belt-walking direction, and the height of the annular protrusions of the extension rollers decreases along the belt-walking direction.

[0037] Specifically, a first extension roller 5, a second extension roller 6 and a third extension roller 7 are arranged in sequence along the walking direction. The height of the annular protrusion 1 on the second extension roller 6 is 1 / 3 of the height of the annular protrusion 1 on the first extension roller 5; the height of the annular protrusion on the third extension roller 7 is 1 / 3 of the height of the annular protrusion 1 on the second extension roller 6.

[0038] See also Figure 3 The angle of the thread-shaped protrusion 2 perpendicular to the foil running direction is 5° to 30°; the width of the annular protrusion 1 is 3mm to 4mm.

[0039] This embodiment verifies the design of the annular protrusion 1 in the middle of the stretching roller. The height and width of the annular protrusion in the middle of the stretching roller are set to different specifications. The angle of the threaded protrusion 2 relative to the tape running direction is set to 30°. The stretching effect is compared and confirmed. The coating speed is set to 20m / min, the single coating width is 202mm, the total width of the copper foil is 476mm, the width of the middle blank area is 36mm, and the width of the blank areas on both sides is 18mm. The height and width of the annular protrusion 1 on the first stretching roller 5, the second stretching roller 6, and the third stretching roller 7 are set as shown in Table 1. Among them, there are no wrinkles in the blank areas on both sides. The wrinkle width of the middle blank area group 1 is about 0.2mm, the wrinkle width of group 2 is less than 0.05mm, and the wrinkle width of group 3 is between 0.05 and 0.1mm. Group 2 has the best stretching effect.

[0040] Table 1:

[0041]

[0042] The design of the annular protrusion 1 in the middle of the stretching roller selected group 2 to compare the stretching effect of the stretching roller with different angles of the threaded protrusion 2. The settings of different thread angles of the threaded protrusion 2 are shown in Table 2. The coating speed is set to 20m / min, the single coating width is 202mm, the total width of the copper foil is 476mm, the width of the middle blank area is 36mm, and the width of the blank areas on both sides is 18mm. Among them, there is no wrinkling in the blank areas on both sides. The wrinkle width of the middle blank area at angle 1 is about 0.1mm, the wrinkle width at angle 2 is less than 0.05mm, the wrinkle width at angle 3 is less than 0.05mm, and the wrinkle width at angle 4 is about 0.1mm. The thread angle, that is, the angle between the thread direction and the perpendicular to the foil running direction, is best controlled between 15° and 30°.

[0043] Table 2:

[0044]

[0045] It should be noted that in Figure 3 and Figure 5 In the diagram, the arrow direction is the tape running direction.

[0046] Although the above description of the specific implementation methods of the present invention is combined with the accompanying drawings, it does not limit the scope of protection of the present invention. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present invention, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present invention.

Claims

1. A flattening device for coating pole pieces of lithium-ion batteries, comprising an extension roller and a correction roller, characterized in that: The stretching roller is provided with an annular protrusion and a thread-shaped protrusion, and the thread-shaped protrusion is symmetrically arranged on both sides of the annular protrusion; A plurality of raised particle points are provided on the thread-shaped protrusion; The height of the annular protrusion of the stretching roller decreases along the belt running direction; The angle of the thread-shaped protrusion perpendicular to the foil running direction is 5° to 30°.

2. A flattening device for coating a lithium-ion battery electrode according to claim 1, characterized in that: The raised particle points are arranged at equal intervals.

3. The flattening device for coating a lithium-ion battery electrode according to claim 1, characterized in that: A plurality of extension rollers are arranged along the belt running direction.

4. A flattening device for coating pole pieces of lithium-ion batteries according to claim 1 or 3, characterized in that: A first extension roller, a second extension roller and a third extension roller are arranged in sequence along the walking direction; the height of the annular protrusion on the second extension roller is 1 / 3 of the height of the annular protrusion on the first extension roller; the height of the annular protrusion on the third extension roller is 1 / 3 of the height of the annular protrusion on the second extension roller.

5. The flattening device for coating a lithium-ion battery electrode according to claim 1, characterized in that: The position of the annular protrusion corresponds to the coating blank position area.

6. The flattening device for coating a lithium-ion battery electrode according to claim 1, characterized in that: The width of the annular protrusion is 3mm~4mm.

7. A flattening device for coating a lithium-ion battery electrode according to claim 1 or 2, characterized in that: The raised particle points are arc-shaped.

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