A lithium film composite tape, a manufacturing apparatus thereof, and a manufacturing method thereof

Abstract

The application relates to the technical field of lithium strip processing, in particular to a lithium film composite strip, a preparation device and a preparation method thereof. The lithium film composite strip comprises a lithium strip, a first coating film and a second coating film. The first coating film is combined on the upper surface of the lithium strip, the second coating film is combined on the lower surface of the lithium strip, and the surfaces of the first coating film and the second coating film are provided with through holes with uniform spacing. In this way, the through holes are arranged on the first coating film and the second coating film, the surface of the lithium strip can be filled into the through holes during drawing and pressing, and the connection tightness with the first coating film and the second coating film is improved.

Description

Technical Field

[0001] This invention relates to the field of lithium strip processing technology, specifically to a lithium film composite strip, a preparation apparatus, and a preparation method thereof. Background Technology

[0002] Lithium metal is a silvery-white soft metal with a density only 1 / 5 that of aluminum, making it the lightest metal found in nature. Combined with its other excellent properties, it is widely used in numerous fields such as atomic energy, nuclear energy, aerospace, metallurgy, chemical industry, machinery, glass and ceramics, air conditioning and refrigeration, medicine and health, organic synthesis, new energy, and agriculture. It is known as the "industrial MSG" and is a key metal material in the high-tech development of the 21st century. When used as a negative electrode, lithium metal is processed into lithium strips or lithium sheets. According to the electron migration theory of battery charging and discharging, electron migration occurs on the surface of the electrode. To reduce the amount of lithium metal used, improve its utilization rate, and increase battery power and discharge current, lithium metal electrodes are generally processed into lithium strips or lithium sheets.

[0003] When lithium strips are processed into electrodes, the electrolyte will reduce and decompose on the surface of negative electrodes such as graphite, forming a solid electrolyte interphase (SEI) film. This permanently consumes a large amount of lithium from the positive electrode, resulting in a low coulombic efficiency (ICE) in the first cycle, which reduces the capacity and energy density of the lithium-ion battery. Therefore, it is necessary to replenish lithium on the electrode sheets to offset the irreversible lithium loss caused by the formation of the SEI film, so as to improve the total capacity and energy density of the battery. This is usually achieved by attaching a polymer film to the surface of the lithium strip.

[0004] Existing processing methods, such as the Chinese patent with publication number CN108615846A, disclose a power battery lithium film composite device and method. In this method, during the conveying process before the baseband is composited with the two lithium films, the liner film on one side of each of the two lithium films is peeled off simultaneously. During the conveying process before the composited finished film is wound, the liner film on the other side of each of the two lithium films is peeled off simultaneously. However, the adhesion between the composite film and the lithium strip is not ideal in this processing method. Summary of the Invention

[0005] To address the above problems, this invention provides a lithium film composite tape, a preparation apparatus, and a preparation method thereof.

[0006] The technical solution adopted is a lithium film composite tape, including a lithium tape, a first coating and a second coating. The first coating is laminated on the upper surface of the lithium tape, and the second coating is laminated on the lower surface of the lithium tape. The surfaces of the first coating and the second coating are provided with through holes with uniform spacing. The uniform thickness of the lithium film composite tape is 80-200μm.

[0007] Furthermore, it also includes a third coating and a fourth coating, with the third coating laminated on the first coating and the fourth coating laminated on the second coating.

[0008] Furthermore, the lithium strip is a metallic lithium strip or a lithium alloy strip, wherein the lithium alloy strip is composed of lithium and one or more of yttrium, silver, copper, lead, silicon, magnesium, aluminum, indium, boron, tin, zinc, and antimony;

[0009] The first coating, the second coating, the third coating, and the fourth coating are all made of polyester film, polyethylene film, or polypropylene film.

[0010] This application also provides an adapted lithium film composite tape preparation apparatus, including a lithium tape unwinding mechanism, a primary rolling mechanism, and a lithium tape winding mechanism;

[0011] The lithium strip unwinding mechanism is used to output the lithium strip;

[0012] A primary pressing mechanism is used to press the first and second coatings onto the lithium strip;

[0013] The lithium strip winding mechanism winds up the compressed lithium strip.

[0014] Furthermore, the lithium strip unwinding mechanism includes a first unwinding roller, a first guide roller, and a second guide roller. The first guide roller is located between the first unwinding roller and the second guide roller, and the lithium strip is wound on the first unwinding roller and output horizontally via the first unwinding roller and the second guide roller.

[0015] The primary calendering mechanism includes a second unwinding roller, a third unwinding roller, a third guide roller, a fourth guide roller, a fifth guide roller, a sixth guide roller, a first calendering roller, and a second calendering roller. The second unwinding roller, the third guide roller, and the fourth guide roller are located above the lithium strip unwinding mechanism, and the third guide roller is located between the second unwinding roller and the fourth guide roller. The first coating film is wound on the second unwinding roller and output towards the first calendering roller via the third guide roller and the fourth guide roller.

[0016] The third unwinding roller, the fifth guide roller, and the sixth guide roller are located below the lithium strip unwinding mechanism, with the fifth guide roller located between the third unwinding roller and the sixth guide roller. The second coating is wound on the third unwinding roller and output towards the second calendering roller via the fifth guide roller and the sixth guide roller.

[0017] The first calendering roller and the second calendering roller are arranged vertically, with the first calendering roller located above the second calendering roller. The lithium strip can pass between the first calendering roller and the second calendering roller. The first calendering roller presses the first coating onto the upper surface of the lithium strip, and the second calendering roller presses the second coating onto the lower surface of the lithium strip.

[0018] The lithium strip winding mechanism includes a winding roller, an eleventh guide roller, and a twelfth guide roller, with the eleventh guide roller located between the winding roller and the twelfth guide roller.

[0019] Optionally, the lithium film composite tape preparation apparatus also includes a secondary rolling mechanism and a slitting mechanism;

[0020] A primary pressing mechanism is used to press the first and second coatings onto the lithium strip to produce a primary lithium film composite strip.

[0021] The secondary pressing mechanism is used to press the third and fourth coatings onto the primary lithium film composite tape to obtain the secondary lithium film composite tape.

[0022] The slitting mechanism cuts the secondary lithium film composite tape into the required width and produces the lithium film composite tape.

[0023] The lithium tape winding mechanism winds up the lithium film composite tape.

[0024] Furthermore, the secondary calendering mechanism includes a fourth unwinding roller, a fifth unwinding roller, a seventh guide roller, an eighth guide roller, a ninth guide roller, a tenth guide roller, a third calendering roller, and a fourth calendering roller. The fourth unwinding roller, the seventh guide roller, and the eighth guide roller are located above the primary lithium film composite belt, and the seventh guide roller is located between the fourth unwinding roller and the eighth guide roller. The third coating is wound on the fourth unwinding roller and output towards the third calendering roller via the seventh guide roller and the eighth guide roller.

[0025] The fifth unwinding roller, the ninth guide roller, and the tenth guide roller are located below the primary lithium film composite belt, and the ninth guide roller is located between the fifth unwinding roller and the tenth guide roller. The fourth coating is wound on the fifth unwinding roller and output to the fourth calendering roller via the ninth guide roller and the tenth guide roller.

[0026] The third and fourth calendering rollers are vertically arranged, with the third calendering roller located above the fourth calendering roller. The primary lithium film composite belt can pass between the third and fourth calendering rollers. The third calendering roller presses the third coating onto the upper surface of the primary lithium film composite belt, and the fourth calendering roller presses the fourth coating onto the lower surface of the primary lithium film composite belt.

[0027] The slitting mechanism includes a slitting plate, which is located on both sides of the secondary lithium film composite belt. The slitting plate can slit both sides of the secondary lithium film composite belt.

[0028] This application also provides a method for preparing a lithium film composite tape, including the following steps:

[0029] S1. Prepare a primary lithium film composite strip by pressing the first coating and the second coating onto the upper and lower surfaces of the lithium strip, respectively;

[0030] S2. Prepare a secondary lithium film composite strip by pressing the third and fourth coatings onto the upper and lower surfaces of the lithium strip, respectively.

[0031] S3. Slitting: The secondary lithium film composite tape is slitted on both sides by a slitting mechanism to obtain the lithium film composite tape.

[0032] Furthermore, the surfaces of the first and second coatings are treated to form through holes with uniform spacing.

[0033] Optionally, the temperature may be raised during the intermediate pressing process and then lowered after pressing is completed.

[0034] During the pressing process in S2, the temperature rises first and then decreases after pressing is complete.

[0035] The beneficial effects of the present invention include at least one of the following;

[0036] 1. The present invention provides support to the upper and lower surfaces of the lithium strip by attaching a coating to it, which can effectively improve the strength of the lithium strip.

[0037] 2. The double-rolling process allows the coating on the lithium strip surface to adhere more fully, improving the overall adhesion. Attached Figure Description

[0038] Figure 1 A schematic diagram of the lithium film composite tape preparation device;

[0039] Figure 2 This is a schematic diagram of a primary rolling mechanism;

[0040] Figure 3 This is a schematic diagram of a primary lithium film composite strip structure;

[0041] Figure 4 This is a schematic diagram of a secondary lithium film composite strip structure;

[0042] Figure 5 This is a schematic diagram of the secondary rolling mechanism.

[0043] Figure 6 This is a schematic diagram of the lithium film composite tape structure after slicing;

[0044] In the attached diagram, 1 represents the first unwinding roll, 2 the second unwinding roll, 3 the third unwinding roll, 4 the fourth unwinding roll, 5 the fifth unwinding roll, 6 the first calendering roll, 7 the second calendering roll, 8 the third calendering roll, 9 the fourth calendering roll, 10 the take-up roll, 11 the first guide roll, 12 the second guide roll, 13 the horizontal roll, 14 the third guide roll, 15 the fourth guide roll, 16 the fifth guide roll, 17 the sixth guide roll, and 18 the seventh guide roll. 19. Eighth guide roller; 20. Ninth guide roller; 21. Tenth guide roller; 22. Slitting plate; 23. First side pressure roller; 24. Second side pressure roller; 25. Eleventh guide roller; 26. Twelfth guide roller; 27. Lithium belt; 28. Primary lithium film composite belt; 29. ​​First coating; 30. Second coating; 31. Third coating; 32. Fourth coating; 33. Secondary lithium film composite belt; 34. Slitting belt; 35. Through hole; 36. Lithium film composite belt. Detailed Implementation

[0045] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0046] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0047] This embodiment provides a lithium film composite tape including a lithium strip 27, a first coating 29 and a second coating 30. The first coating 29 is laminated on the upper surface of the lithium strip 27, and the second coating 30 is laminated on the lower surface of the lithium strip 27. The surfaces of the first coating 29 and the second coating 30 are provided with through holes 35 with uniform spacing. The uniform thickness of the lithium film composite tape is 80-200μm.

[0048] The purpose of this design is to improve the bonding tightness with the first and second coatings by providing through holes in the first and second coatings, so that the lithium strip surface can fill the through holes during the rolling process.

[0049] It should be noted that during the calendering and lamination process, a lubricant can be applied to the contact surfaces between the first and second coatings and the lithium strip. The lubricant can be one or more of graphite powder, mineral oil, and synthetic oil.

[0050] In this embodiment, a third coating 31 and a fourth coating 32 are also included. The third coating 31 is laminated on the first coating 29, and the fourth coating 32 is laminated on the second coating 30.

[0051] Meanwhile, the lithium strip 27 is a metallic lithium strip or a lithium alloy strip, wherein the lithium alloy strip is one or more of lithium and yttrium, silver, copper, lead, silicon, magnesium, aluminum, indium, boron, tin, zinc, and antimony;

[0052] The first coating 29, the second coating 30, the third coating 31 and the fourth coating 32 are all made of polyester film, polyethylene film and polypropylene film.

[0053] The purpose of this design is that, based on the first and second coatings, the presence of through holes allows a portion of the lithium strip to enter the through holes. By continuing to press the third and fourth coatings onto the through holes, the through holes are covered and come into contact with the lithium strip that has entered them, thus improving the adhesion of the lithium film composite strip.

[0054] It should be noted that during the calendering and lamination process, a lubricant can be applied to the contact surface between the third coating and the first coating, and to the contact surface between the fourth coating and the second coating. The lubricant can be one or more of graphite powder, mineral oil, and synthetic oil.

[0055] During processing, the thickness ratio of the lithium strip, first coating, second coating, third coating and fourth coating in the lithium film composite tape is usually 6:1:1:1:1.

[0056] like Figure 1 As shown, in this embodiment, a lithium film composite tape preparation apparatus is also provided, including a lithium tape unwinding mechanism, a primary rolling mechanism, and a lithium tape winding mechanism;

[0057] The lithium strip unwinding mechanism is used to output the lithium strip 27;

[0058] The primary pressing mechanism is used to press the first coating 29 and the second coating 30 onto the lithium strip 27;

[0059] The lithium strip winding mechanism winds up the pressed lithium strip.

[0060] like Figure 2 As shown, the lithium strip unwinding mechanism includes a first unwinding roller 1, a first guide roller 11, and a second guide roller 12. The first guide roller 11 is located between the first unwinding roller 1 and the second guide roller 12, and the lithium strip 27 is wound on the first unwinding roller 1 and output horizontally via the first unwinding roller 1 and the second guide roller 12.

[0061] The primary calendering mechanism includes a second unwinding roller 2, a third unwinding roller 3, a third guide roller 14, a fourth guide roller 15, a fifth guide roller 16, a sixth guide roller 17, a first calendering roller 6, and a second calendering roller 7. The second unwinding roller 2, the third guide roller 14, and the fourth guide roller 15 are located above the lithium strip unwinding mechanism, and the third guide roller 14 is located between the second unwinding roller 2 and the fourth guide roller 15. The first coating 29 is wound on the second unwinding roller 2 and output towards the first calendering roller 6 via the third guide roller 14 and the fourth guide roller 15.

[0062] The third unwinding roller 3, the fifth guide roller 16, and the sixth guide roller 17 are located below the lithium strip unwinding mechanism, and the fifth guide roller 16 is located between the third unwinding roller 3 and the sixth guide roller 17. The second coating 30 is wound on the third unwinding roller 3 and output towards the second calendering roller 7 via the fifth guide roller 16 and the sixth guide roller 17.

[0063] The first calendering roller 6 and the second calendering roller 7 are arranged vertically, with the first calendering roller 6 located above the second calendering roller 7. The lithium strip 27 can pass between the first calendering roller 6 and the second calendering roller 7. The first calendering roller 6 presses the first coating 29 onto the upper surface of the lithium strip 27, and the second calendering roller 7 presses the second coating 30 onto the lower surface of the lithium strip 27.

[0064] The lithium strip winding mechanism includes a winding roller 10, an eleventh guide roller 25, and a twelfth guide roller 26, with the eleventh guide roller 25 located between the winding roller 10 and the twelfth guide roller 26.

[0065] like Figure 3 , Figure 4 and Figure 6 As shown, the lithium film composite tape preparation device also includes a secondary rolling mechanism and a slitting mechanism;

[0066] The primary pressing mechanism is used to press the first coating 29 and the second coating 30 onto the lithium strip 27 to obtain a primary lithium film composite strip 28.

[0067] The secondary pressing mechanism is used to press the third coating 31 and the fourth coating 32 onto the primary lithium film composite belt 28 to obtain the secondary lithium film composite belt 33.

[0068] The slitting mechanism slits the secondary lithium film composite strip 33 into the required width and produces the lithium film composite strip 36.

[0069] The lithium strip winding mechanism winds up the lithium film composite strip 36.

[0070] like Figure 5 As shown, the secondary calendering mechanism includes a fourth unwinding roller 4, a fifth unwinding roller 5, a seventh guide roller 18, an eighth guide roller 19, a ninth guide roller 20, a tenth guide roller 21, a third calendering roller 8, and a fourth calendering roller 9. The fourth unwinding roller 4, the seventh guide roller 18, and the eighth guide roller 19 are located above the primary lithium film composite belt 28, and the seventh guide roller 18 is located between the fourth unwinding roller 4 and the eighth guide roller 19. The third coating 31 is wound on the fourth unwinding roller 4 and output towards the third calendering roller 8 via the seventh guide roller 18 and the eighth guide roller 19.

[0071] The fifth unwinding roller 5, the ninth guide roller 20, and the tenth guide roller 21 are located below the primary lithium film composite belt 28, and the ninth guide roller 20 is located between the fifth unwinding roller 5 and the tenth guide roller 21. The fourth coating film 32 is wound on the fifth unwinding roller 5 and output towards the fourth calendering roller 9 via the ninth guide roller 20 and the tenth guide roller 21.

[0072] The third calendering roller 8 and the fourth calendering roller 9 are arranged vertically, with the third calendering roller 8 located above the fourth calendering roller 9. The primary lithium film composite belt 28 can pass between the third calendering roller 8 and the fourth calendering roller 9. The third calendering roller 8 presses the third coating 31 onto the upper surface of the primary lithium film composite belt 28, and the fourth calendering roller 9 presses the fourth coating 32 onto the lower surface of the primary lithium film composite belt 28.

[0073] The slitting mechanism includes a slitting plate 22, which is disposed on both sides of the secondary lithium film composite belt 33. The slitting plate 22 can slit both sides of the secondary lithium film composite belt 33.

[0074] In practice, the first and second coatings are rolled onto the lithium strip surface by the first and second rolling rollers. The guide rollers are mainly used to change the specific angles at which the lithium strip, the first rolling roller, and the second rolling roller enter.

[0075] Typically, multiple sets of horizontal rollers are installed between the first and second calendering mechanisms, enabling the primary lithium film composite belt formed after calendering in the first calendering mechanism to be transported horizontally over long distances.

[0076] Then, the third and fourth coatings are rolled onto the surface of the primary lithium film composite belt through the third and fourth rolling rollers to form the secondary lithium film composite belt.

[0077] It should be noted that, under normal circumstances, the width of the first, second, third, and fourth coatings should be greater than the width of the lithium strip. For example, taking a 30mm wide lithium strip, the width of the first and second coatings is usually 33-36mm, while the width of the third and fourth coatings is 40-44mm. This results in the first and second coatings wrapping around the surface of the lithium strip, and the third and fourth coatings wrapping around the surface of the first and second coatings.

[0078] Since the first, second, third, and fourth coatings only serve to cover the material, they need to be cut by a slitting mechanism during use. In this embodiment, the slitting plate 22 is used to cut the slitting strip 34 formed by the first, second, third, and fourth coatings on both sides of the lithium strip to make it have a suitable size.

[0079] Furthermore, after slitting, the first, second, third, and fourth coatings remain on the lithium strip surface; only the excess dimensions have been cut off. Therefore, to ensure a tight connection at the slitting edges, edge pressure rollers are typically used, such as... Figure 1 The first and second side pressure rollers in the process are mainly used to stretch and press the edges of the lithium strip.

[0080] In this embodiment, a method for preparing a lithium film composite strip is also provided, including the following steps:

[0081] S1. Prepare a primary lithium film composite strip 28 by pressing a first coating 29 and a second coating 30 onto the upper and lower surfaces of the lithium strip 27, respectively.

[0082] S2. Prepare a secondary lithium film composite strip 33, and press the third coating 31 and the fourth coating 32 onto the upper and lower surfaces of the lithium strip 27, respectively.

[0083] S3. Slitting: The secondary lithium film composite belt 33 is slitted on both sides by a slitting mechanism to obtain the lithium film composite belt 36.

[0084] Meanwhile, in S1, the surfaces of the first coating 29 and the second coating 30 are processed to form through holes 35 with uniform spacing.

[0085] Meanwhile, the temperature rises first during pressing in S1, and then decreases after pressing is completed;

[0086] During the pressing process in S2, the temperature rises first and then decreases after pressing is complete.

[0087] The purpose of this design is to effectively improve the strength of the lithium strip by attaching a coating to its upper and lower surfaces for support. The double-rolling process allows the coating on the lithium strip surface to adhere more fully, improving overall adhesion.

[0088] In practice, etching is usually used to create through holes on the surfaces of the first and second coatings. Material impact is usually more effective for removal.

[0089] It should be noted that the through hole can be in various shapes, such as round or square.

[0090] During the entire calendering process, the temperature rises during pressing and then decreases after pressing is completed. Taking the first calendering as an example, the lithium strip, the first coating, and the second coating are initially at room temperature. As the distance between the first and second calendering rollers gradually decreases, the temperature rises until it reaches 70 degrees Celsius and is maintained for 3-5 minutes. After calendering is completed, the temperature drops sharply to 40 degrees Celsius within 1 minute. The second calendering also adopts this form.

[0091] The purpose of this design is to improve the adhesion between the coatings and between the coating and the lithium strip through this temperature rise and rapid drop, making them less likely to separate before use.

[0092] In some applications, a solid electrolyte interface layer can be formed on the lithium strip surface by coating it with perfluoropentane, perfluorotripentane, etc., and then the first and second coatings are applied.

[0093] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium film composite tape, characterized in that, The lithium film composite strip includes a lithium strip (27), a first coating (29), and a second coating (30). The first coating (29) is laminated on the upper surface of the lithium strip (27), and the second coating (30) is laminated on the lower surface of the lithium strip (27). The surfaces of the first coating (29) and the second coating (30) are provided with through holes (35) with uniform spacing. The uniform thickness of the lithium film composite strip is 80-200μm. It also includes a third coating (31) and a fourth coating (32), wherein the third coating (31) is laminated on the first coating (29) and the fourth coating (32) is laminated on the second coating (30).

2. The lithium film composite tape according to claim 1, characterized in that, The lithium strip (27) is a metallic lithium strip or a lithium alloy strip, wherein the lithium alloy strip is one or more of lithium and yttrium, silver, copper, lead, silicon, magnesium, aluminum, indium, boron, tin, zinc, and antimony; The first coating (29), the second coating (30), the third coating (31) and the fourth coating (32) are all of polyester film, polyethylene film and polypropylene film.

3. A lithium film composite tape preparation apparatus, characterized in that, It includes a lithium strip unwinding mechanism, a primary rolling mechanism, and a lithium strip rewinding mechanism; The lithium strip unwinding mechanism is used to output the lithium strip (27); The primary pressing mechanism is used to press the first coating (29) and the second coating (30) onto the lithium strip (27); The lithium strip winding mechanism winds up the compressed lithium strip. The lithium film composite tape preparation device also includes a secondary rolling mechanism and a slitting mechanism; The primary pressing mechanism is used to press the first coating (29) and the second coating (30) onto the lithium strip (27) to obtain a primary lithium film composite strip (28). The secondary pressing mechanism is used to press the third coating (31) and the fourth coating (32) onto the primary lithium film composite belt (28) to obtain the secondary lithium film composite belt (33). The slitting mechanism slits the secondary lithium film composite strip (33) into the required width and produces the lithium film composite strip (36). The lithium strip winding mechanism winds up the lithium film composite strip (36).

4. The lithium film composite tape preparation apparatus according to claim 3, characterized in that, The lithium strip unwinding mechanism includes a first unwinding roller (1), a first guide roller (11), and a second guide roller (12). The first guide roller (11) is located between the first unwinding roller (1) and the second guide roller (12), and the lithium strip (27) is wound on the first unwinding roller (1) and output horizontally via the first unwinding roller (1) and the second guide roller (12). The primary rolling mechanism includes a second unwinding roller (2), a third unwinding roller (3), a third guide roller (14), a fourth guide roller (15), a fifth guide roller (16), a sixth guide roller (17), a first rolling roller (6), and a second rolling roller (7). The second unwinding roller (2), the third guide roller (14), and the fourth guide roller (15) are located above the lithium strip unwinding mechanism, and the third guide roller (14) is located between the second unwinding roller (2) and the fourth guide roller (15). The first coating (29) is wound on the second unwinding roller (2) and output towards the first rolling roller (6) via the third guide roller (14) and the fourth guide roller (15). The third unwinding roller (3), the fifth guide roller (16), and the sixth guide roller (17) are located below the lithium strip unwinding mechanism, and the fifth guide roller (16) is located between the third unwinding roller (3) and the sixth guide roller (17). The second coating (30) is wound on the third unwinding roller (3) and output towards the second calendering roller (7) via the fifth guide roller (16) and the sixth guide roller (17). The first calendering roller (6) and the second calendering roller (7) are arranged vertically, with the first calendering roller (6) located above the second calendering roller (7). The lithium strip (27) can pass between the first calendering roller (6) and the second calendering roller (7). The first calendering roller (6) presses the first coating (29) onto the upper surface of the lithium strip (27), and the second calendering roller (7) presses the second coating (30) onto the lower surface of the lithium strip (27). The lithium strip winding mechanism includes a winding roller (10), an eleventh guide roller (25), and a twelfth guide roller (26), with the eleventh guide roller (25) located between the winding roller (10) and the twelfth guide roller (26).

5. The lithium film composite tape preparation apparatus according to claim 3, characterized in that, The secondary calendering mechanism includes a fourth unwinding roller (4), a fifth unwinding roller (5), a seventh guide roller (18), an eighth guide roller (19), a ninth guide roller (20), a tenth guide roller (21), a third calendering roller (8), and a fourth calendering roller (9). The fourth unwinding roller (4), the seventh guide roller (18), and the eighth guide roller (19) are located above the primary lithium film composite belt (28), and the seventh guide roller (18) is located between the fourth unwinding roller (4) and the eighth guide roller (19). The third coating (31) is wound on the fourth unwinding roller (4) and output towards the third calendering roller (8) via the seventh guide roller (18) and the eighth guide roller (19). The fifth unwinding roller (5), the ninth guide roller (20), and the tenth guide roller (21) are located below the primary lithium film composite belt (28), and the ninth guide roller (20) is located between the fifth unwinding roller (5) and the tenth guide roller (21). The fourth coating (32) is wound on the fifth unwinding roller (5) and output towards the fourth calendering roller (9) via the ninth guide roller (20) and the tenth guide roller (21). The third calendering roller (8) and the fourth calendering roller (9) are arranged vertically, with the third calendering roller (8) located above the fourth calendering roller (9). The primary lithium film composite belt (28) can pass between the third calendering roller (8) and the fourth calendering roller (9). The third calendering roller (8) presses the third coating (31) onto the upper surface of the primary lithium film composite belt (28), and the fourth calendering roller (9) presses the fourth coating (32) onto the lower surface of the primary lithium film composite belt (28). The slitting mechanism includes a slitting plate (22), which is disposed on both sides of the secondary lithium film composite belt (33). The slitting plate (22) can slit both sides of the secondary lithium film composite belt (33).

6. A method for preparing a lithium film composite tape, characterized in that, Includes the following steps: S1. Prepare a primary lithium film composite strip (28) by pressing the first coating (29) and the second coating (30) onto the upper and lower surfaces of the lithium strip (27), respectively; S2. Prepare a secondary lithium film composite strip (33), and press the third coating (31) and the fourth coating (32) onto the upper and lower surfaces of the lithium strip (27), respectively; S3. Cutting: The lithium film composite tape (33) is cut on both sides by a cutting mechanism to obtain the lithium film composite tape (36). In S1, the surfaces of the first coating (29) and the second coating (30) are processed to form through holes (35) with uniform spacing.

7. The method for preparing a lithium film composite tape according to claim 6, characterized in that, During the pressing process in S1, the temperature rises first and then decreases after the pressing is completed. During the pressing process in S2, the temperature rises first and then decreases after pressing is complete.

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