Belt breakage prevention device for lithium battery pole piece rolling process

Abstract

The utility model discloses a belt breakage prevention device for a lithium battery pole piece rolling process, which comprises a splayed roller, a concave-convex roller, a floating roller, a tension roller and a pinch roller which are sequentially arranged on a rack along the pole piece conveying direction, wherein the concave surface of the concave-convex roller corresponds to a coating area of the pole piece, and the convex surface of the concave-convex roller corresponds to a foil area of the pole piece; the heating assembly is arranged in front of the concave-convex roller and close to the concave-convex roller, and the heating end of the heating assembly is located below the foil area of the pole piece. According to the utility model, the heating assembly is additionally arranged to heat the foil material area before stretching, the original cold stretching is changed into hot stretching, the stretching tension can be reduced by 70%, the foil material area fracture caused by large tension is prevented, the stretching of the foil material area can be completed no matter the elongation percentage of a conventional pole piece is about 7 per thousand or the large elongation percentage of a high-pressure dense pole piece is more than 15 per thousand, and the production efficiency is greatly improved. And the pole piece can be continuously wound without being broken.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium - ion battery production, and particularly relates to an anti - break belt device for the rolling process of lithium - battery electrode sheets. Background Art

[0002] The rolling of electrode sheets is an important link in the production process of lithium - ion batteries. It can enhance the bonding strength between the active material and the foil, prevent peeling during electrolyte immersion and battery use, and at the same time improve the energy density and power density of lithium - batteries and optimize the electrochemical performance.

[0003] Since the thickness of the coating area of the electrode sheet is much larger than that of the foil area, the coating area will extend due to rolling during electrode sheet rolling, but the foil area will not. This leads to a difference in elongation rate between the coating area and the foil area after electrode sheet rolling. To solve the difference in elongation rate, the current industry solution is to perform cold stretching on the foil area. However, because it is cold stretching, the tension of the electrode sheet is large, and there is a large tensile stress in the foil area. Also, due to microscopic defects such as pinholes and cracked edges in the production process of the foil itself, the foil area is prone to breakage during cold stretching. Summary of the Utility Model

[0004] To solve the above - mentioned deficiencies in the prior art, the utility model aims to provide an anti - break belt device for the rolling process of lithium - battery electrode sheets, so as to achieve continuous winding of the electrode sheet without breaking the belt when solving the extension problem of the foil area of the electrode sheet, thereby improving production efficiency and reducing electrode sheet waste.

[0005] To achieve the above - mentioned purpose, the technical solution adopted by the utility model is as follows: An anti - break belt device for the rolling process of lithium - battery electrode sheets, along the electrode sheet conveying direction, includes an eight - shaped roller, a concave - convex roller, a floating roller, a tension roller, and a pinch roller sequentially arranged on a frame; wherein, the concave surface of the concave - convex roller corresponds to the coating area of the electrode sheet, and the convex surface of the concave - convex roller corresponds to the foil area of the electrode sheet;

[0006] It also includes a heating component arranged before and adjacent to the concave - convex roller, and the heating end of the heating component is located below the foil area of the electrode sheet.

[0007] As a limitation of the utility model, it also includes a temperature sensor corresponding to the foil area of the electrode sheet.

[0008] As another limitation of the utility model, the heating component is assembled on the frame through a three - axis slide table to have the adjustment functions in the X, Y, and Z directions.

[0009] As a further limitation of the utility model, the concave - convex roller includes a flat roller and a Teflon tape pasted on the outer surface of the flat roller to form a convex surface, and the part of the flat roller without the Teflon tape forms a concave surface.

[0010] As a further limitation of the present utility model, it further includes a cooling fan with an air outlet facing the embossing roller to cool the embossing roller.

[0011] As a further limitation of the present utility model, an inner channel for refrigerant circulation is provided in the flat roller.

[0012] As other limitations of the present utility model, a set of eight-shaped rollers is provided on each side of the pole piece to horizontally flatten the pole piece.

[0013] Due to the adoption of the above technical solutions, compared with the prior art, the beneficial effects achieved by the present utility model are as follows:

[0014] (1) The present utility model provides a new means to solve the problem of elongation in the foil area of the pole piece (the problem of different elongation rates between the coated area and the foil area after the pole piece is roll-pressed). Specifically, by adding a heating component to heat the foil area before stretching, the original cold stretching is changed to hot stretching. The elastic modulus of the foil decreases and the deformation resistance decreases in the hot state. At the same time, due to the thermal expansion of the foil, a considerable part of the elongation has occurred, so a smaller stretching tension is required, and the foil can reach the required elongation rate. Compared with traditional cold stretching, the tension can be reduced by 70%. The reduction of the stretching tension can reduce the stress concentration in the foil area, prevent the fracture of the foil area caused by large tension, and reduce the risk of broken belts.

[0015] Whether it is the elongation rate of about 7‰ of the conventional pole piece or the large elongation rate of more than 15‰ of the high-voltage dense pole piece, the present utility model can complete it, and can realize continuous winding of the pole piece without broken belts, improve production efficiency, and greatly reduce the waste of pole pieces.

[0016] (2) The temperature sensor provided in the present utility model can monitor the temperature of the foil area in real time, and then the output power of the heating component can be automatically adjusted through temperature feedback to ensure that the heating temperature required by the process can be met.

[0017] (3) The heating component in the present utility model is assembled on the frame through a three-axis sliding table, and has the adjustment functions in the X, Y, and Z directions, which can meet the different configuration requirements of different processes.

[0018] (4) The embossing roller in the present utility model is the first roller that the pole piece passes through after leaving the rolling mill, which can prevent the pole piece from wrinkling and breaking when winding around the roller due to inconsistent elongation rates in the coated area and the foil area of the pole piece. The embossing roller in the present utility model is composed of a flat roller with a Teflon tape pasted on it, and the embossing amount can be adjusted according to the process requirements; in addition, the embossing roller in the present utility model is a cold roller with a cooling function (realized by passing refrigerant inside or blowing cold air outside), and after the pole piece enters the embossing roller, it can cold-set the elongation of the foil area, thereby preventing the reduction of the elongation rate due to the cold shrinkage of the foil area after the pole piece exits the embossing roller.

[0019] By adjusting parameters such as the tension, heating temperature, and thickness of the Teflon tape, the elongation rate of the foil area after the electrode sheet exits the concave-convex roller can be made equal to or slightly greater than that of the coating area.

[0020] (5) In the present utility model, the eight-shaped rollers arranged on both sides of the electrode sheet can flatten the electrode sheet horizontally and effectively improve the wrinkles of the electrode sheet. Description of the Drawings

[0021] The present utility model will be further described in detail below in conjunction with the drawings and specific embodiments.

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the present utility model;

[0023] In the figure: 1, eight-shaped roller; 2, concave-convex roller; 3, floating roller; 4, tension roller; 5, pinch roller; 6, heating component; 7, electrode sheet; 8, rolling roller; 9, frame. Specific Embodiments

[0024] The following describes the preferred embodiments of the present utility model in conjunction with the drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and understanding the present utility model, and are not used to limit the present utility model.

[0025] Embodiment A device for preventing belt breakage in the roller pressing process of lithium battery electrode sheets

[0026] As Figure 1 shown, along the conveying direction of the electrode sheet 7, this embodiment includes an eight-shaped roller 1, a concave-convex roller 2, a floating roller 3, a tension roller 4, and a pinch roller 5 sequentially arranged on the frame 9.

[0027] The eight-shaped roller 1, floating roller 3, tension roller 4, and pinch roller 5 in this embodiment are all existing structures. Among them, the eight-shaped roller 1 is located at the front end, and a set is provided on each side of the electrode sheet 7. Before the electrode sheet 7 enters the concave-convex roller 2, it first passes through the eight-shaped roller 1 for horizontal flattening, which can effectively improve the wrinkles of the electrode sheet 7. The floating roller 3 is arranged behind the concave-convex roller 2 and is used to adjust the winding tension of the electrode sheet 7; the tension roller 4 is arranged behind the floating roller 3 and is used to monitor the tension in real time; the pinch roller 5 is arranged behind the tension roller 4 and is used to match the speed to ensure the stability of the electrode sheet 7 during transmission.

[0028] The concave-convex roller 2 is used to prevent the electrode sheet 7 from breaking during winding due to inconsistent elongation rates in the coating area and the foil area after exiting the rolling roller 8. The concave-convex roller 2 in this embodiment includes a flat roller and multiple sections of Teflon tape pasted on the outer surface of the flat roller. Each section of Teflon tape is wound around the outer surface of the flat roller along the circumferential direction of the flat roller, and the formed thickness can be adjusted according to actual process requirements; multiple sections of Teflon tape are arranged at equal intervals along the axial direction of the flat roller to form the convex surface of the concave-convex roller 2. The area on the flat roller where the Teflon tape is not pasted forms the concave surface of the concave-convex roller 2.

[0029] When the electrode sheet 7 winds around the roller, the coating area corresponds to the concave surface of the concave-convex roller 2, and the foil area corresponds to the convex surface of the concave-convex roller 2.

[0030] Furthermore, this embodiment further includes a heating component 6 disposed between the eight-shaped roller 1 and the concave-convex roller 2 and closely adjacent to the concave-convex roller 2. The heating component 6 uses an existing electromagnetic heating component 6, and its electromagnetic heating coil (i.e., the heating end) is located below the foil area of the electrode sheet 7. It should be noted that since the electrode sheet 7 has multiple foil areas in the transverse direction, usually multiple heating components 6 are provided, corresponding to the foil areas one by one.

[0031] The heating components 6 in this embodiment are all assembled on the frame 9 through a three-axis slide table, and have the adjustment functions in the X, Y, and Z directions, so that the position of the heating end of the heating component 6 can be flexibly adjusted, thereby meeting the different configuration requirements of different processes. Of course, the heating component 6 can also be assembled in other ways to make it have the adjustment functions in the X, Y, and Z directions. For example: a structure that can move in the X, Y, and Z directions is formed by assembling three guide rails, and then the position of the slider on the guide rail is manually adjusted and fixed, or the position of the slider on the guide rail is adjusted and fixed by a cylinder. The heating component 6 is assembled on the Z-direction guide rail.

[0032] In order to monitor the temperature of the foil area of the electrode sheet 7, this embodiment also sets a temperature sensor corresponding to the foil area of the electrode sheet 7 on the frame 9.

[0033] More specifically, the concave-convex roller 2 in this embodiment is a cold roller, which is used to prevent the electrode sheet 7 from cold shrinking after passing through the concave-convex roller 2 and causing a decrease in the elongation rate. The cold roller can be realized in any of the following ways: one is to add a cold air blower, so that the air outlet of the cold air blower faces the concave-convex roller 2, and the concave-convex roller 2 has a cooling function by blowing cold air externally; the other is to set an inner channel in the flat roller of the concave-convex roller 2, and pass a refrigerant through the inner channel to make the concave-convex roller 2 have a cooling function.

[0034] This embodiment, as an independent mechanism, can be installed at the inlet or outlet of the rolling mill. The center distance between the concave-convex roller 2 and the rolling roller 8 in the rolling mill is usually within 50 cm. This embodiment takes the installation at the outlet of the rolling mill as an example to introduce its usage process:

[0035] After the electrode sheet 7 exits the rolling roller 8, it first passes through the eight-shaped roller 1 for horizontal flattening, and then is heated by the heating component 6 for the foil area of the electrode sheet 7, so that the foil area of the electrode sheet 7 enters the concave-convex roller 2 in a hot state; after the electrode sheet 7 enters the concave-convex roller 2, its foil area corresponds to the convex surface of the concave-convex roller 2, and the coating area corresponds to the concave surface of the concave-convex roller 2, and the foil area is extended by means of the convex surface; after the foil area of the electrode sheet 7 is extended and cold-set by the concave-convex roller 2, it then passes through the floating roller 3, the tension roller 4, and the pinch roller 5 in sequence, and finally is wound up.

[0036] It should be noted that the above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An anti-breaking belt device for the rolling process of lithium battery electrode sheets, characterized in that: Along the conveying direction of the electrode plate, there are successively arranged an eight-shaped roller, a concave-convex roller, a floating roller, a tension roller and a pinch roller on the frame; among them, the concave surface of the concave-convex roller corresponds to the coating area of the electrode plate, and the convex surface of the concave-convex roller corresponds to the foil area of the electrode plate. It further includes a heating component arranged before and adjacent to the concave-convex roller, and the heating end of the heating component is located below the foil area of the electrode plate.

2. The anti-break belt device for the lithium battery pole piece rolling process according to claim 1, characterized in that: It further includes a temperature sensor arranged corresponding to the foil area of the electrode plate.

3. The anti-breaking device for the lithium battery pole piece rolling process according to claim 1 or 2, characterized in that: The heating component is assembled on the frame through a three-axis slide table to have the adjustment functions in three directions of X, Y and Z.

4. The anti-breaking belt device for the lithium battery pole piece rolling process according to claim 3, wherein: The concave-convex roller includes a flat roller and a Teflon tape pasted on the outer surface of the flat roller to form a convex surface, and the part of the flat roller where the Teflon tape is not pasted forms a concave surface.

5. The anti-breaking device for the lithium battery pole piece rolling process according to claim 4, characterized in that: It further includes a cooling fan with an air outlet facing the concave-convex roller to cool the concave-convex roller.

6. The anti-breaking belt device for the lithium battery pole piece rolling process according to claim 4, characterized in that: The flat roller is provided with an inner channel for refrigerant circulation.

7. A device for preventing belt breakage in the rolling process of lithium battery electrode sheets according to any one of claims 1, 2, 4 - 6, characterized in that: There is a set of eight-shaped rollers on each side of the electrode plate to flatten the electrode plate laterally.

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