Lithium electrode plate stretching device

Abstract

The utility model discloses a lithium electrode plate stretching device which comprises a stretching roller assembly and a connecting roller assembly, and the connecting roller assembly and the stretching roller assembly are connected and coaxially arranged. The lithium electrode plate comprises a coating area and an empty foil area, in the axial direction perpendicular to the stretching roller assembly or the connecting roller assembly, the projection of the coating area is located in the range of the connecting roller assembly, at least part of the projection of the empty foil area is located in the range of the stretching roller assembly, and the stretching roller assembly is used for supporting the empty foil area and stretching the empty foil area in a hot stretching mode. The lithium electrode plate stretching device disclosed by the utility model realizes hot stretching of empty foil areas of a plurality of lithium electrode plates, avoids the problem of cold stretching fracture of foils, ensures the ductility of the empty foil areas to be consistent with that of a coating area, ensures the smooth proceeding of subsequent procedures, and is simple in structure, convenient to disassemble and assemble and low in cost. And the device can be quickly assembled so as to be suitable for stretching empty foil areas with different width sizes.

Description

Technical Field

[0001] This utility model belongs to the technical field of battery production equipment, specifically relating to a lithium electrode sheet stretching device and a stretching roller. Background Technology

[0002] With the continuous development of lithium-ion battery technology, the requirements for battery performance are increasing. Among them, the manufacturing quality of battery electrodes directly affects the overall performance of the battery. Electrodes are the basic components of batteries. The production process of electrodes is roughly as follows: a slurry is coated on a metal foil to form a coated area and an empty foil area. After the material strip is dried and rolled, the empty foil area is cut to form electrode tabs. Finally, the material strip is slit to form electrode sheets.

[0003] Currently, multi-coating processes are commonly used for coating metal foil, resulting in multiple coated areas and multiple uncoated areas. Due to the differences in physical properties between the coated and uncoated areas, their elongation rates during subsequent rolling are inconsistent, easily leading to edge waviness and even fine wrinkles. Therefore, stretching of the uncoated areas is necessary to match the elongation deformation of the coated areas after rolling. Traditional methods for stretching the uncoated areas often employ cold drawing, which involves mechanically stretching the uncoated areas at room temperature or lower. While cold drawing can achieve some elongation of the uncoated areas, it has significant limitations. The uncoated areas lack sufficient plasticity and are prone to breakage. During cold drawing, because the plastic deformation capacity of the metal foil is limited at lower temperatures, breakage is highly likely when the stretch exceeds its plastic limit. To address the issue of the ductility of the empty foil area, another method involves attaching Teflon tape of the corresponding width to the empty foil area to ensure that the ductility of the empty foil area matches that of the coated area. However, when manufacturing different types of electrode sheets, the width of the empty foil area varies. Using this method requires removing the Teflon tape and reattaching it with a new one of the corresponding width, which significantly reduces production efficiency.

[0004] In summary, existing technologies still have many limitations and shortcomings in solving the problem of insufficient ductility of the empty foil area during the manufacturing process of lithium-ion battery electrodes, and a more efficient, reliable and flexible method is urgently needed. Utility Model Content

[0005] The purpose of this invention is to provide a lithium electrode sheet stretching device that addresses the aforementioned shortcomings. This device enables the thermal stretching of empty foil areas of multiple lithium electrode sheets, ensuring consistent ductility between the empty foil areas and the coated areas, thus guaranteeing smooth operation of subsequent processes. It features a simple structure, easy disassembly and assembly, and rapid assembly, making it suitable for stretching empty foil areas of varying widths. To achieve the above objectives, this invention provides the following technical solution:

[0006] A lithium electrode sheet stretching device includes a stretching roller assembly and a connecting roller assembly, wherein the connecting roller assembly is connected to and coaxially arranged with the stretching roller assembly; the lithium electrode sheet includes a coated area and an empty foil area, wherein, in an axial direction perpendicular to the stretching roller assembly or the connecting roller assembly, the projection of the coated area is located within the range of the connecting roller assembly, and the projection of the empty foil area is at least partially located within the range of the stretching roller assembly; the stretching roller assembly is used to support the empty foil area and stretch the empty foil area by thermal stretching.

[0007] Furthermore, the stretching roller assembly includes a stretching roller and a heating mechanism; the stretching roller includes a rolling surface, and the rolling surface surrounds the axis of the stretching roller to form a receiving cavity; the heating mechanism is housed in the receiving cavity and heats the rolling surface, so that when the lithium electrode sheet passes through the stretching roller, the empty foil area is thermally stretched by the rolling surface.

[0008] Furthermore, the stretching roller also includes a connecting end face, which is disposed at at least one end of the stretching roller in the axial direction. The connecting end face supports and connects the roller pressing surface and seals the receiving cavity.

[0009] Furthermore, the connecting end face is provided with a first heating through hole, and a power line passes through the first heating through hole. The power line is connected to the heating mechanism, and the heating mechanism is a resistance heating element.

[0010] Furthermore, a temperature sensor is provided inside the receiving cavity, and the temperature sensor is connected to the rolling surface to detect the temperature of the rolling surface.

[0011] Furthermore, the connecting roller assembly includes at least one connecting roller; along the axial direction of the connecting roller, at least one end of the connecting roller is tightly connected to the connecting end face of the stretching roller by an interference fit.

[0012] Furthermore, the connecting roller is provided with a second heating through hole, which extends through both end faces of the connecting roller. The second heating through hole is connected to the first heating through hole, and the power line passes through the second heating through hole.

[0013] Furthermore, in the axial direction perpendicular to the connecting roller, the radius of the stretching roller is larger than the radius of the connecting roller.

[0014] Furthermore, it also includes a rotating shaft, on the outer periphery of which a stretching roller assembly and a connecting roller assembly are sleeved; and along the axial direction of the rotating shaft, multiple stretching rollers and connecting rollers are respectively spaced apart, with at least two stretching rollers located at both ends of the connecting rollers; one end of the rotating shaft is connected to the output end of the drive unit.

[0015] A stretching apparatus includes a rolling mechanism and the aforementioned lithium electrode sheet stretching apparatus; the stretching roller apparatus is used to stretch the empty foil area of ​​the lithium electrode sheet; the rolling mechanism is used to roll the coated area of ​​the lithium electrode sheet.

[0016] The beneficial effects of the utility model are:

[0017] This utility model discloses a lithium electrode sheet stretching device, including a stretching roller assembly and a connecting roller assembly. The connecting roller assembly is connected to and coaxially arranged with the stretching roller assembly. The lithium electrode sheet includes a coated area and an empty foil area. In an axial direction perpendicular to the stretching roller assembly or the connecting roller assembly, the projection of the coated area is located within the range of the connecting roller assembly, and the projection of the empty foil area is at least partially located within the range of the stretching roller assembly. The stretching roller assembly supports the empty foil area and stretches the empty foil area by thermal stretching. This utility model's lithium electrode sheet stretching device enables thermal stretching of the empty foil areas of multiple lithium electrode sheets, avoiding the problem of foil breakage during cold stretching. It ensures that the ductility of the empty foil area and the coated area are consistent, guaranteeing the smooth progress of subsequent processes. The structure is simple, easy to disassemble and assemble, and can be quickly assembled to be suitable for stretching empty foil areas of different widths. Attached Figure Description

[0018] Figure 1 This is an exploded structural diagram of the lithium electrode sheet stretching device of this utility model;

[0019] Figure 2 This is an exploded structural diagram of the lithium electrode sheet stretching device of this utility model from another perspective.

[0020] Figure 3 This is a three-dimensional structural schematic diagram of the connecting roller in the lithium electrode sheet stretching device of this utility model;

[0021] Figure 4 This is an exploded structural diagram of the stretching roller in the lithium electrode sheet stretching device of this utility model.

[0022] In the attached diagram: 1-Stretch roller assembly, 2-Connecting roller assembly, 3-Stretch roller, 4-Receiving cavity, 5-Connecting roller, 6-Rotating shaft, 7-Power supply, 8-Electrical slip ring, 9-Roller surface, 10-Connecting end face, 11-First heating through hole, 12-Second heating through hole, 13-Resistance heating element. Detailed Implementation

[0023] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0024] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also mean including the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0025] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0026] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. The meaning of such spatial relative terms includes different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0027] Example 1:

[0028] See attached Figure 1 . Figure 1The specific structure of the lithium electrode sheet stretching device of this invention is shown. The lithium electrode sheet stretching device of this invention includes a stretching roller assembly 1 and a connecting roller assembly 2. The connecting roller assembly 2 is connected to and coaxially arranged with the stretching roller assembly 1. The connecting roller assembly 2 mainly serves a connecting function, linking the stretching roller assembly 1. The lithium electrode sheet includes a coated area and an empty foil area. In an axial direction perpendicular to the stretching roller assembly 1 or the connecting roller assembly 2, the projection of the coated area is located within the range of the connecting roller assembly 2, and the projection of the empty foil area is at least partially located within the range of the stretching roller assembly 1. The stretching roller assembly 1 supports the empty foil area and stretches the empty foil area by thermal stretching. When the lithium electrode sheet stretching device of this invention stretches the empty foil area, the lithium electrode sheet passes through the stretching device in a tensile state. The stretching roller assembly 1 contacts and supports the empty foil area of ​​the lithium electrode sheet, and the empty foil area is stretched by thermal stretching.

[0029] Specifically, the stretching roller assembly 1 includes at least two stretching rollers 3, and the connecting roller assembly 2 includes at least one connecting roller 5. When two coatings are applied to the foil, the lithium electrode sheet has three empty foil areas and two coated areas, so three stretching rollers 3 and two connecting rollers 5 are provided, as shown below. Figure 1 As shown, three stretching rollers 3 are connected by two connecting rollers 5. Each connecting roller 5 has a stretching roller 3 connected to both ends. The three stretching rollers 3 correspond to the three empty foil areas of the lithium electrode sheet, and the two connecting rollers 5 correspond to the two coating areas of the lithium electrode sheet. Both the stretching rollers 3 and the connecting rollers 5 can be cylindrical and coaxially arranged. The radius of the stretching roller 3 is larger than the radius of the connecting roller 5, and the difference in radius between them should be greater than the thickness of the slurry coated on the foil. When the lithium electrode sheet passes through the lithium electrode sheet stretching device, only the stretching rollers 3 contact the empty foil areas of the lithium electrode sheet, thereby supporting and stretching the empty foil areas. The connecting rollers 5 correspond to the coating areas and provide contact support to the coating areas. The coating areas of the lithium electrode sheet are not affected by the stretching of the stretching rollers 3.

[0030] Specifically, Figure 3 The specific structure of the stretching roller 3 is shown. The stretching roller 3 includes a roller pressing surface 9 and a connecting end face 10. The roller pressing surface 9 surrounds the axis of the stretching roller 3 to form a receiving cavity 4. The connecting end face 10 is located at both ends of the stretching roller 3 in the axial direction. The connecting end face 10 supports and connects the roller pressing surface 9 and seals both ends of the receiving cavity 4. Figure 2The specific structure of the connecting roller 5 is shown. Along the axial direction of the connecting roller 5, at least one end of the connecting roller 5 is tightly connected to the connecting end face 10 of the stretching roller 3. The connection can be made by interference fit. Connecting heads or connecting grooves can be set at both ends of the stretching roller 3 respectively. Corresponding connecting grooves or connecting heads are set at the corresponding ends of the connecting roller 5. The connecting head is inserted into the connecting groove and the connecting roller 5 is connected to the stretching roller 3 by interference fit. The structure is simple, easy to disassemble and assemble, and can be quickly assembled to be suitable for the empty foil area and coating area of ​​multiple lithium electrode sheets of different widths.

[0031] Specifically, the stretching roller 3 also includes a heating mechanism housed within the receiving cavity 4. This housing means that the volume of the heating mechanism is less than or equal to the volume of the receiving cavity 4. The heating mechanism can be completely enclosed within the receiving cavity 4, or it can partially protrude from the receiving cavity 4 and be compressed by the connecting end face 10 to enclose it within the receiving cavity 4. The heating mechanism is used to heat the rolling surface 9 of the stretching roller 3. When the lithium electrode sheet passes through the lithium electrode sheet stretching device, the empty foil area of ​​the lithium electrode sheet contacts the rolling surface 9 of the stretching roller 3. The rolling surface 9 supports and tensions the empty foil area and thermally stretches it under the action of the heating mechanism.

[0032] This utility model's lithium electrode sheet stretching device achieves thermal stretching of the empty foil area of ​​the lithium electrode sheet, avoiding the problem of foil breakage during cold drawing, and ensuring consistent ductility between the empty foil area and the coated area, thus guaranteeing the smooth progress of subsequent processes. The heating mechanism is either a resistance heating element 13 or an induction heating element. The resistance heating element 13 is positioned on the inner wall of the roller pressing surface 9 facing the receiving cavity 4. Current generates Joule heat through the resistance heating element 13 to heat the roller pressing surface 9. Resistance heating is inexpensive and simple to manufacture. Alternatively, an induction heating element is placed inside the receiving cavity 4, with a metal component inside. Current generates eddy currents through the induction heating element to heat the metal, which then transfers the heat to the roller pressing surface 9.

[0033] Furthermore, a temperature sensor is also installed inside the receiving cavity 4. The temperature sensor is connected to the roller pressing surface 9 to detect the heating temperature of the roller pressing surface 9 in real time. That is, the temperature sensor monitors the working status of the heating mechanism in real time and provides feedback to the operator, who can then adjust the heating temperature of the heating mechanism according to actual needs. The temperature sensor can also be a thermocouple, semiconductor, infrared temperature sensor, fiber optic temperature sensor, etc.

[0034] Specifically, the connecting end face 10 is provided with a first heating through hole 11, and the connecting roller 5 is provided with a second heating through hole 12 at the position corresponding to the first heating through hole 11. The second heating through hole 12 passes through the two end faces of the connecting roller 5 and communicates with the first heating through hole 11. A power line is passed through the first heating through hole 11 and the second heating through hole 12, and the power line is connected to the heating mechanism.

[0035] Specifically, the lithium electrode sheet stretching device of this utility model also includes a rotating shaft 6. One end of the rotating shaft 6 is connected to the output end of the drive unit. The drive unit drives the rotating shaft 6 to rotate, and the stretching roller assembly 1 and the connecting roller assembly 2 are sleeved on the rotating shaft 6. Along the axial direction of the rotating shaft 6, multiple stretching rollers 3 and connecting rollers 5 are respectively spaced apart. At least two stretching rollers 3 are located at both ends of the connecting roller. The stretching rollers 3 and connecting rollers 5 rotate together with the rotating shaft 6, and convey the foil material while stretching the empty foil area of ​​the lithium electrode sheet.

[0036] A power supply 7 is provided at one end of the rotating shaft 6. One end of the power cord passes through the first heating through-hole 11 and the second heating through-hole 12 and is connected to the power supply 7 via an electrical slip ring 8. This ensures that when the stretching roller 3 and the connecting roller 5 rotate with the rotating shaft 6, the power supply 7 supplies power to the heating mechanism through the wire to heat the annular shell of the stretching roller 3. It should be noted that the resistance heating element 13 and the temperature sensor are rotatably connected to the stretching roller 3, and the power cord is rotatably connected to either the stretching roller 3 or the connecting roller 5. Thus, when the stretching roller 3 and the connecting roller 5 rotate with the rotating shaft 6, the power cord, the resistance heating element 13, and the temperature sensor all remain in a fixed state.

[0037] It is understandable that the power cord can also be installed inside the rotating shaft 6. For example, the rotating shaft 6 is a hollow structure with a power cord installed inside. One end of the power cord is connected to the resistance heating element 13, and the other end of the power cord is connected to the power supply 7 through the electrical slip ring 8. The power cord is rotatably connected inside the rotating shaft 6, thereby ensuring that when the stretching roller 3 and the connecting roller 5 rotate with the rotating shaft 6, the power supply 7 supplies power to the heating mechanism through the wire to heat the annular outer shell of the stretching roller 3.

[0038] Example 2:

[0039] A stretching device includes a rolling mechanism and a lithium electrode sheet stretching device as described in Embodiment 1. A lithium electrode sheet stretching device can be provided on each side of the rolling mechanism. The lithium electrode sheet passes through the lithium electrode sheet stretching device, where its empty foil area is first thermally stretched. The lithium electrode sheet then passes through the rolling mechanism, where its coated area is rolled. Finally, the lithium electrode sheet passes through the lithium electrode sheet stretching device again, where its empty foil area is thermally stretched once more. This ensures that the ductility of the empty foil area and the coated area are consistent, guaranteeing the smooth progress of subsequent processes.

[0040] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

[0041] The above embodiments are preferred implementations of this utility model. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this utility model.

Claims

1. A lithium electrode sheet stretching device, characterized in that: It includes a stretching roller assembly (1) and a connecting roller assembly (2). The connecting roller assembly (2) is connected to and coaxially arranged with the stretching roller assembly (1); The lithium electrode sheet includes a coated area and an empty foil area. In an axial direction perpendicular to the stretching roller assembly (1) or the connecting roller assembly (2), the projection of the coated area is located within the range of the connecting roller assembly (2), and the projection of the empty foil area is at least partially located within the range of the stretching roller assembly (1). The stretching roller assembly (1) is used to support the empty foil area and stretch the empty foil area by thermal stretching.

2. The lithium electrode sheet stretching device according to claim 1, characterized in that: The stretching roller assembly (1) includes a stretching roller (3) and a heating mechanism; The stretching roller (3) includes a roller pressing surface (9), and the roller pressing surface (9) is arranged around the axis of the stretching roller (3) to form a receiving cavity (4); the heating mechanism is housed in the receiving cavity (4) and heats the roller pressing surface (9). When the lithium electrode sheet passes through the stretching roller (3), the empty foil area is thermally stretched by the roller pressing surface (9).

3. The lithium electrode sheet stretching device according to claim 2, characterized in that: The stretching roller (3) further includes a connecting end face (10), which is located at at least one end of the stretching roller (3) in the axial direction. The connecting end face (10) supports and connects the roller pressing surface (9) and seals the receiving cavity.

4. The lithium electrode sheet stretching device according to claim 3, characterized in that: The connecting end face (10) is provided with a first heating through hole (11), and a power line is passed through the first heating through hole (11). The power line is connected to the heating mechanism, which is a resistance heating element (13) or an induction heating element.

5. A lithium electrode sheet stretching device according to claim 2, characterized in that: A temperature sensor is provided inside the receiving cavity (4), and the temperature sensor is connected to the rolling surface (9) to detect the temperature of the rolling surface (9).

6. The lithium electrode sheet stretching device according to claim 4, characterized in that: The connecting roller assembly (2) includes at least one connecting roller (5); along the axial direction of the connecting roller (5), at least one end of the connecting roller (5) is tightly connected to the connecting end face (10) of the stretching roller (3).

7. A lithium electrode sheet stretching device according to claim 6, characterized in that: The connecting roller (5) is provided with a second heating through hole (12), which passes through the two end faces of the connecting roller (5), and the second heating through hole (12) is connected to the first heating through hole (11), and the power line passes through the second heating through hole (12).

8. A lithium electrode sheet stretching device according to claim 6, characterized in that: In the axial direction perpendicular to the connecting roller (5), the radius of the stretching roller (3) is greater than the radius of the connecting roller (5).

9. A lithium electrode sheet stretching device according to claim 6, characterized in that: It also includes a rotating shaft (6), on the outer periphery of which the stretching roller assembly (1) and the connecting roller assembly (2) are sleeved; and along the axial direction of the rotating shaft (6), the stretching roller (3) and the connecting roller (5) are respectively spaced apart in multiples, with at least two stretching rollers (3) located at both ends of the connecting roller (5); one end of the rotating shaft (6) is connected to the output end of the drive unit.

10. A tensioning device, characterized in that: It includes a rolling mechanism and a lithium electrode sheet stretching device as described in any one of claims 1 to 9; the stretching roller device is used to stretch the empty foil area of ​​the lithium electrode sheet; the rolling mechanism is used to roll the coated area of ​​the lithium electrode sheet.

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