A kind of drawing forming device for polypropylene lithium battery diaphragm production

Abstract

The application relates to the technical field of battery diaphragm production, and discloses a stretching and forming device for polypropylene lithium battery diaphragm production, which comprises a base, mounting frame one and mounting frame two arranged on the base, stretching equipment arranged on the mounting frame one, winding equipment arranged on the mounting frame two, a guide cutting mechanism, a bridge support fixed on the mounting frame two, a guide roller rotatably supported on the bridge support, and a track opened on the bridge support in the axial direction of the guide roller, a sliding sleeve slidably assembled in the track, a spline rod vertically slidably arranged in the sliding sleeve, and a cutting knife arranged at the bottom end of the spline rod. The guide cutting mechanism is arranged to linearly cut the diaphragm adhered to the surface of the guide roller, so that the cutting edge deviation and the uneven end surface caused by uneven force during manual cutting of the cutting knife are avoided.

Description

Technical Field

[0001] This invention relates to the field of battery separator production technology, and in particular to a stretching and forming apparatus for the production of polypropylene lithium battery separators. Background Technology

[0002] As a key inner component of lithium-ion batteries, polypropylene lithium-ion battery separators have been the subject of numerous research efforts in recent years to further improve their electrochemical performance. Researchers have explored introducing functional modification components into the polypropylene matrix. For example, by utilizing the reversible redox activity of polyoxometalate components under an electric field and the electron transfer mediating effect of viologen derivatives, they have suppressed lithium dendrite growth, reducing the risk of internal short circuits caused by separator puncture. Simultaneously, this can promote the rapid migration of lithium ions between the separator pores and the electrolyte interface, reducing battery internal resistance and thus improving the long-term cycle stability of the battery.

[0003] In the current industrial production of lithium battery separators, the stretching and forming process is mainly divided into two categories: dry unidirectional stretching and wet bidirectional stretching. The operation steps of the dry unidirectional stretching process are as follows: polypropylene raw material is melted and plasticized in an extruder, and a pre-formed thick film with a specific orientation lamellar structure is obtained through a casting process; then, the pre-formed thick film is introduced into a stretching and forming device, and it passes through multiple sets of stretching rollers in sequence to complete the directional stretching of micropores in the length direction; finally, the stretched and formed separator is wound up by a take-up roller.

[0004] However, in the small-batch trial production of miniaturized stretch forming equipment, during the actual operation of the diaphragm cutting process after winding, operators typically use a blade to manually cut and separate the wound film roll. During this separation process, as the cutting action gradually advances along the film width, the portion already cut at the blade tip first breaks free from the constraint of the winding tension system, forming a free end. Because this free end region loses its original tension, and because the polypropylene diaphragm is thin and has low bending stiffness, it is difficult to maintain its planar shape on its own rigidity, and under the influence of gravity, it begins to... Sagging occurs; at the same time, the uncut membrane segment is still subjected to residual tension from the winding roller. During the cutting process, the tension state on both sides of the membrane is different, which can easily cause the film to slip laterally and wrinkle locally at the cut tip, resulting in overall skewness of the cut and uneven cut end face. In addition, the membrane edge at the cut may re-adhere to the adjacent membrane layers under the squeezing and dragging action of the cutting action. Once interlayer adhesion is formed, it may cause local tearing in the subsequent unwinding or stacking process, thereby affecting the processing and use performance of the membrane and the assembly yield of the battery. Summary of the Invention

[0005] The purpose of this invention is to provide a stretching and forming apparatus for the production of polypropylene lithium battery separators, so as to solve the problems mentioned in the background art.

[0006] The present invention provides a stretching and forming apparatus for the production of polypropylene lithium battery separators, which adopts the following technical solution: A stretching and forming apparatus for the production of polypropylene lithium battery separators, comprising: The base, and mounting brackets one and two mounted on the base, wherein mounting bracket one is equipped with a stretching device and mounting bracket two is equipped with a winding device, and the base also includes: A guide cutting mechanism is mounted on the second mounting frame. The guide cutting mechanism includes a bridge bracket fixed on the second mounting frame, a guide roller rotatably supported on the bridge bracket, and a track extending axially along the guide roller and opened on the bridge bracket. A sliding sleeve is slidably assembled in the track, and a spline rod is slidably passed through the sliding sleeve along the vertical direction. A cutting blade is installed at the bottom end of the spline rod. The cutting blade is used to cut when the diaphragm is attached to the upper surface of the guide roller. An anti-detachment mechanism is installed on a bridge-type support. The anti-detachment mechanism includes two sets of connecting plates symmetrically slidably mounted on the bridge-type support. Each set of connecting plates is slidably connected to a sliding plate. The sliding plate is equipped with a telescopic part and a pressing roller. The pressing roller is used to press the diaphragm in the cutting state and flatten it to both sides along the length of the diaphragm.

[0007] Furthermore, a handle is fixed to the top of the spline rod, and a spring is sleeved on the outside of the spline rod, with the two ends of the spring abutting against the handle and the sliding sleeve respectively.

[0008] Furthermore, the anti-detachment mechanism also includes pressing blocks symmetrically fixed on both sides of the spline rod, the pressing blocks pressing against the connecting plate as the spline rod moves downward; Both sets of extrusion blocks have wedge blocks fixed on opposite sides, and wedge plates are fixed on the slide plate accordingly. The surfaces of the wedge plates and wedge blocks that fit together are both set as inclined surfaces to convert the vertical displacement of the spline rod into the horizontal lateral movement of the slide plate.

[0009] Furthermore, each of the connecting plates has a sliding limit rod that is fixed to the bridge bracket. The limit rod is provided with a second spring, and the two ends of the second spring are respectively fixed to the bridge bracket and the connecting plate. A protrusion is fixed on the limiting rod, and the lower surface of the protrusion contacts the upper surface of the connecting plate.

[0010] Furthermore, the telescopic part includes an insert rod and a sleeve rod slidably sleeved at the bottom end of the insert rod. A spring is provided on the outer surface of the insert rod, and the two ends of the spring are fixed to the insert rod and the sleeve rod respectively. The pressing roller is rotatably connected to the lower end of the sleeve rod through a rotating shaft.

[0011] Furthermore, the insert rod and the slide plate are fixed together by a sliding rod, and a sliding groove is provided on the connecting plate for the sliding rod to slide and engage, and a spring is fixed between the sliding rod and the groove wall.

[0012] Furthermore, a negative pressure cavity is provided inside the guide roller, and multiple sets of adsorption holes are arrayed along the axial and circumferential directions on the roller surface of the guide roller. One end of the guide roller is rotatably connected to an interface end that is connected to an external negative pressure source.

[0013] Furthermore, a magnetic block one is fixed to the inner wall of one end of the track, and a magnetic block two is fixed to the side of the sliding sleeve facing the magnetic block one, with the magnetic block one and the magnetic block two forming a magnetic attraction contact.

[0014] Furthermore, the extrusion block is rotatably mounted with rollers on the side facing the connecting plate.

[0015] Furthermore, a rubber layer is fitted onto the outer circumferential surface of the pressing roller.

[0016] The beneficial effects of this invention are: 1. By setting up a guiding cutting mechanism, after winding is completed, the cutting blade can move smoothly along the track to cut the diaphragm attached to the surface of the guide roller in a straight line. This avoids the skewing and uneven end face caused by uneven force when cutting manually with a hand-held blade. At the same time, the negative pressure chamber and roller surface adsorption holes built into the guide roller adsorb and fix the diaphragm during cutting, replacing the tension function provided by the winding tension. This keeps the diaphragm flat in the cutting area, eliminates the sagging of the free end, and uses continuous airflow to force convection cooling of the cutting area, effectively suppressing the micro-melting adhesion of the cutting edge and ensuring the cutting quality.

[0017] 2. By setting up an anti-detachment mechanism, while the cutting blade is cutting downwards, the pressing roller presses down and presses the diaphragm on both sides of the cut, preventing the cut film segment from falling off due to loss of tension constraint. At the same time, with the cooperation of the wedge block and the inclined surface of the wedge plate, the translational movement of pushing the cut is synchronously converted into the flattening action of the pressing roller along the length of the diaphragm, eliminating local wrinkles and side slippage in the cutting area, ensuring that the film surface is always flat and taut during the cutting process, and the cut is straight, improving cutting consistency and ease of operation. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the base, mounting frame 2, winding equipment and guide cutting mechanism of the present invention; Figure 3 This is a three-dimensional structural diagram of the guide cutting mechanism of the present invention; Figure 4 This is a three-dimensional structural diagram of the bridge support, guide roller, and anti-detachment mechanism of the present invention. Figure 5 This is a three-dimensional cross-sectional view of the guide roller of the present invention; Figure 6This is a partial three-dimensional cross-sectional view of the guiding cutting mechanism and the anti-detachment mechanism of the present invention; Figure 7 This is a partial three-dimensional structural diagram of the bridge support of the present invention; Figure 8 This is a three-dimensional structural diagram of the sliding sleeve, spline rod, cutting blade, handle, and spring of the present invention. Figure 9 An exploded three-dimensional structural diagram of the sliding sleeve, spline rod, cutting blade, and spring of the present invention; Figure 10 This is a partial three-dimensional cross-sectional view of the anti-detachment mechanism of the present invention; Figure 11 This is a three-dimensional structural diagram of the spline rod, extrusion block, and wedge block of the present invention; Figure 12 This is a partial three-dimensional structural diagram of the connecting plate of the present invention; Figure 13 This is a three-dimensional structural diagram of the telescopic part of the present invention.

[0019] In the picture: 1. Base; 2. Mounting bracket one; 3. Stretching equipment; 4. Mounting bracket two; 5. Winding equipment; 6. Guide cutting mechanism; 61. Bridge bracket; 62. Guide roller; 621. Negative pressure chamber; 622. Adsorption hole; 623. Interface end; 63. Track; 631. Magnetic block one; 64. Sliding sleeve; 641. Magnetic block two; 65. Spline rod; 66. Cutting knife; 67. Handle; 68. Spring one; 7. Anti-detachment mechanism; 71. Connecting plate; 711. Limiting rod; 712. Spring two; 713. Protrusion; 714. Slide groove; 72. Slide plate; 73. Telescopic part; 731. Insert rod; 732. Sleeve rod; 733. Spring three; 74. Pressing roller; 75. Extrusion block; 751. Roller; 76. Wedge block; 77. Wedge-shaped long plate; 78. Sliding rod; 79. Spring four. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Reference Figures 1-2 The present invention provides a stretching and forming apparatus for the production of polypropylene lithium battery separators, including a base 1 and a mounting frame 2 and a mounting frame 4 disposed on the base 1. The mounting frame 2 is equipped with a stretching device 3 for performing directional stretching of a pre-formed thick film, and the mounting frame 4 is equipped with a winding device 5 for winding and collecting the formed separator. The mounting frame 4 is also equipped with a controller.

[0022] Reference Figures 3-9It also includes a guide cutting mechanism 6, which is mounted on the second mounting frame 4. It is used to guide the diaphragm during winding and to cut it after winding. The guide cutting mechanism 6 includes a bridge bracket 61 fixed on the second mounting frame 4, a guide roller 62 rotatably supported on the bridge bracket 61, and a track 63 extending axially along the guide roller 62 and opened on the bridge bracket 61. A sliding sleeve 64 is slidably assembled in the track 63. A spline rod 65 is slidably passed through the sliding sleeve 64 vertically. A cutting blade 66 is installed at the bottom end of the spline rod 65. The cutting blade 66 is located directly above the central axis of the guide roller 62 and is used to cut the diaphragm when it is attached to the upper surface of the guide roller 62. During normal winding operation, the guide roller 62 acts as a guide roller to guide and transport the diaphragm. At this time, the cutting blade 66 is idle above the guide roller 62 and does not affect the film feeding. When cutting is required, the cutting blade 66 is moved downward and contacts the diaphragm by pressing down the spline rod 65.

[0023] A handle 67 is fixed to the top of the spline rod 65, and a spring 68 is sleeved on the outside of the spline rod 65. The two ends of the spring 68 abut against the handle 67 and the sliding sleeve 64, respectively. After cutting, the handle 67 is released, the elastic potential energy stored in the spring 68 is released, driving the spline rod 65 to automatically return to its original position, and causing the cutting blade 66 to disengage from the diaphragm.

[0024] Among them, reference Figures 7-8 A magnetic block 631 is fixed to the inner wall of one end of the track 63. A magnetic block 641 is fixed to the side of the sliding sleeve 64 facing the magnetic block 631. The magnetic block 631 and the magnetic block 641 form a magnetic attraction contact. The magnetic block 631 is located at the starting end of the track 63. Through the magnetic attraction between the magnetic block 631 and the magnetic block 641, when the cutting blade 66 is not performing a cutting action, the magnetic attraction force holds the sliding sleeve 64 at the end of the track 63, preventing the sliding sleeve 64 from moving randomly in the track 63 due to factors such as equipment vibration, and ensuring that the cutting blade 66 always stays in the predetermined initial position when not in operation.

[0025] Reference Figure 5It should be noted that a negative pressure cavity 621 is provided inside the guide roller 62, and multiple sets of adsorption holes 622 are arrayed along the axial and circumferential directions on the roller surface of the guide roller 62. The adsorption holes 622 are connected to the negative pressure cavity 621. One end of the guide roller 62 is rotatably connected to an interface end 623 that connects to an external negative pressure source. During cutting, the external negative pressure source draws air from the negative pressure cavity 621 through the interface end 623, generating negative pressure at the adsorption holes 622, which tightly adsorbs the diaphragm onto the surface of the guide roller 62. Through the adsorption effect, on the one hand, it replaces the tension function originally provided by the winding tension, keeping the diaphragm in the cutting area flat and eliminating the cut deviation caused by the sagging of the free end. On the other hand, during the cutting process, air continuously flows through the adsorption holes 622, carrying away the heat generated by the friction of the blade film, and implementing forced convection cooling on the cutting area, effectively suppressing the micro-melting adhesion phenomenon caused by the accumulation of frictional heat at the cut edge.

[0026] Furthermore, refer to Figures 10-13 It also includes an anti-detachment mechanism 7 installed on the bridge support 61. The anti-detachment mechanism 7 is used to press and flatten the diaphragm on both sides of the cut while the cutting blade 66 is cutting downwards, to prevent the cut membrane segment from falling off, and to eliminate wrinkling and slippage caused by tension asymmetry.

[0027] Specifically, the anti-detachment mechanism 7 includes two sets of connecting plates 71 symmetrically slidably mounted on the bridge bracket 61. Each set of connecting plates 71 is slidably connected to a slide plate 72. The slide plate 72 is equipped with a telescopic part 73 and a pressing roller 74. The pressing roller 74 is used to press the diaphragm in the cutting state and flatten it to both sides along the length of the diaphragm. The pressing roller 74 moves down synchronously with the downward movement of the cutting blade 66, applying a pressing force to the diaphragm and fixing the membrane segments on both sides of the cut to the guide roller 62 respectively, so that the diaphragm will not fall off or shift due to loss of tension constraint during the cutting process.

[0028] The anti-detachment mechanism 7 also includes pressing blocks 75 symmetrically fixed on both sides of the spline rod 65. When the spline rod 65 moves downward, the pressing blocks 75 press against the connecting plate 71, and then continue to move downward to contact and press the diaphragm. Thus, the pressing and cutting actions are both driven by the same pressing operation, without the need for additional independent operation steps.

[0029] Reference Figure 10Each connecting plate 71 has a sliding limit rod 711, which is fixed to the bridge bracket 61. A second spring 712 is provided on the limit rod 711, with its two ends fixed to the bridge bracket 61 and the connecting plate 71, respectively. A protrusion 713 is fixed on the limit rod 711, with its lower surface in contact with the upper surface of the connecting plate 71. The limit rod 711 provides guidance for the upward and downward sliding of the connecting plate 71, and the protrusion 713 limits the position of the connecting plate 71 when it is reset. After cutting, the second spring 712 drives the connecting plate 71 to reset upward, causing the pressing roller 74 to leave the diaphragm surface, making it easy to remove the cut film roll.

[0030] Reference Figure 11 The extrusion block 75 is rotatably mounted with a roller 751 on the side facing the connecting plate 71. When the extrusion block 75 descends with the spline rod 65 to contact the connecting plate 71, the operator pushes the spline rod 65 along the direction of the track 63. At this time, the roller 751 rolls along the length of the connecting plate 71, changing the sliding friction between the extrusion block 75 and the connecting plate 71 into rolling friction. This reduces the wear on the contact surface between the extrusion block 75 and the connecting plate 71, and avoids pushing jams or uneven force caused by excessive sliding friction resistance. This reduces the changes in cutting speed and cut jump caused by thrust fluctuations, which is conducive to forming a smooth and regular cut.

[0031] Furthermore, wedge-shaped blocks 76 are fixed to the opposite sides of both sets of extrusion blocks 75, and wedge-shaped long plates 77 are correspondingly fixed on the slide plate 72. The surfaces of the wedge-shaped long plates 77 and the wedge-shaped blocks 76 that are in contact with each other are both set as inclined surfaces to convert the vertical displacement of the spline rod 65 into the horizontal lateral movement of the slide plate 72. When the spline rod 65 is pressed down and the extrusion block 75 contacts the connecting plate 71, the inclined surface of the wedge-shaped block 76 contacts the inclined surface of the wedge-shaped long plate 77. At this time, the spline rod 65 slides with the sliding sleeve 64 in the track 63, causing the extrusion block 75 and the wedge-shaped block 76 to slide synchronously. At this time, the inclined surface of the wedge-shaped block 76 extrudes the wedge. The inclined surface of the long plate 77 drives the two sets of sliding plates 72 to move outward to both sides of the diaphragm length direction, thereby driving the two sets of pressing rollers 74 to move in opposite directions, applying a flattening force to the diaphragm, flattening the diaphragm in the cutting area, eliminating local wrinkles, and ensuring that the film surface is flat and the cut is straight during cutting. It should be noted that when the extrusion block 75 and the wedge block 76 continue to move with the spline rod 65, the inclined surface of the wedge block 76 gradually disengages from the inclined surface of the wedge long plate 77, and then the wedge block 76 moves to fit against the flat section of the wedge long plate 77. At this time, the two sets of pressing rollers 74 remain in the current flattening position.

[0032] Two sets of pressing rollers 74 are symmetrically distributed on both sides of the central axis of the guide roller 62, and are located on both sides of the cutting blade 66 along the length of the diaphragm. In the unflattened state, the pressing rollers 74 are within the projection range of the roller surface of the guide roller 62, ensuring that they can reliably contact the diaphragm attached to the surface of the guide roller 62 when pressing down. After the flattening action is completed, the two sets of pressing rollers 74 move away from the cutting line along the length of the diaphragm, but the maximum outward movement is still limited by the wedge-shaped long plate 77, so that the pressing rollers 74 never exceed the effective support area of ​​the guide roller 62, ensuring that the pressing force applied by the pressing rollers 74 to the diaphragm is always rigidly supported by the roller surface of the guide roller 62, avoiding the failure of pressing due to the pressing rollers 74 moving out of the roller surface range.

[0033] Reference Figure 13 The telescopic part 73 includes an insertion rod 731 and a sleeve rod 732 slidably sleeved on the bottom end of the insertion rod 731. A spring 733 is provided on the outer surface of the insertion rod 731. The two ends of the spring 733 are fixed to the insertion rod 731 and the sleeve rod 732 respectively. The pressing roller 74 is rotatably connected to the lower end of the sleeve rod 732 through a rotating shaft. The spring 733 provides a buffer when the pressing roller 74 contacts the diaphragm to avoid rigid impact damage to the diaphragm surface. At the same time, it enables the pressing roller 74 to always maintain the pressing state on the diaphragm. The outer peripheral surface of the pressing roller 74 is sleeved with a rubber layer. The rubber layer increases the coefficient of friction between the pressing roller 74 and the diaphragm, so that the diaphragm surface does not slip when pressing.

[0034] Reference Figure 13 The insertion rod 731 and the slide plate 72 are fixed together by a slide rod 78. The two ends of the slide rod 78 are fixed to the top of the insertion rod 731 and the bottom of the slide plate 72, respectively. The connecting plate 71 is provided with a slide groove 714 for the slide rod 78 to slide and engage. A spring 79 is fixed between the slide rod 78 and the groove wall of the slide groove 714. After the cutting is completed, the slide plate 72 returns to its original position along the slide groove 714 with the help of the elastic restoring force of the spring 79, which drives the two sets of pressing rollers 74 to move back to the initial position.

[0035] The working principle of this invention is as follows: During the winding operation, the diaphragm is drawn out from the stretching device 3, passes over the upper surface of the guide roller 62, and is wound onto the winding roller of the winding device 5. In this state, the cutting blade 66 is in an idle position above the guide roller 62 under the action of the first spring 68, the sliding sleeve 64 is held at the starting end of the track 63 under the magnetic attraction of the first magnetic block 631 and the second magnetic block 641, and the pressing roller 74 is in a lifted state under the action of the second spring 712.

[0036] When the winding is complete and the diaphragm needs to be cut, the operator holds the handle 67 and presses down on the spline rod 65. The spline rod 65 moves vertically down along the spline groove in the sliding sleeve 64. During the downward movement, the extrusion blocks 75, which are symmetrically fixed on both sides of the spline rod 65, contact the connecting plate 71. The roller 751 presses against the upper surface of the connecting plate 71, pushing the connecting plate 71 to slide down along the limit rod 711. This, in turn, drives the slide plate 72, the telescopic part 73, and the pressing roller 74 to move down synchronously. The spring 733 in the telescopic part 73 provides elastic buffering when the pressing roller 74 contacts the diaphragm, so that the pressing roller 74 presses against the diaphragm surface. At this time, the pressing roller 74 and the cutting blade 66 have both moved down to contact the diaphragm.

[0037] Meanwhile, an external negative pressure source draws air from the negative pressure chamber 621 inside the guide roller 62 through the interface end 623, generating negative pressure at the adsorption hole 622, adsorbing the diaphragm onto the roller surface of the guide roller 62, keeping the diaphragm in the cutting area flat. Subsequently, the operator pushes the spline rod 65 along the track 63, and the sliding sleeve 64 overcomes the magnetic attraction and disengages from the starting end. The cutting blade 66 performs transverse cutting along the width of the diaphragm. In the initial stage of pushing, the inclined surface of the wedge block 76 and the inclined surface of the wedge plate 77 squeeze each other. The vertical displacement of the wedge block 76 is converted into the horizontal transverse movement of the sliding plate 72 through the inclined surface cooperation, driving the two sets of sliding plates 72 to move outward to both sides of the diaphragm length direction, driving the two sets of pressing rollers 74 to move in opposite directions, applying a flattening force along the length direction to the diaphragm, flattening the diaphragm in the cutting area, and eliminating local wrinkles.

[0038] After cutting is completed, the operator releases handle 67, spring 1 68 drives spline rod 65 to automatically return to its original position, cutting blade 66 disengages from diaphragm, spring 2 712 drives connecting plate 71 to return to its original position, driving pressing roller 74 away from diaphragm surface, spring 4 79 drives slide plate 72 to return to its original position along slide groove 714, driving two sets of pressing rollers 74 back to their initial position, then the operator pushes spline rod 65 back to the starting end along track 63, sliding sleeve 64 slides to the end of track 63, magnetic block 1 631 and magnetic block 2 641 re-magnetically adhere to each other, locking sliding sleeve 64 in the initial position.

[0039] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention 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 solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A stretching and forming apparatus for the production of polypropylene lithium battery separators, comprising: The base (1) and mounting brackets 1 (2) and 2 (4) disposed on the base (1), wherein a stretching device (3) is disposed on mounting bracket 1 (2) and a winding device (5) is disposed on mounting bracket 2 (4), characterized in that it further includes: The guide cutting mechanism (6) is set on the second mounting frame (4). The guide cutting mechanism (6) includes a bridge bracket (61) fixed on the second mounting frame (4), a guide roller (62) rotatably supported on the bridge bracket (61), and a track (63) extending axially along the guide roller (62) and opened on the bridge bracket (61). A sliding sleeve (64) is slidably assembled in the track (63). A spline rod (65) is slidably passed through the sliding sleeve (64) in a vertical direction. A cutting blade (66) is installed at the bottom end of the spline rod (65). The cutting blade (66) is used to cut when the diaphragm is attached to the upper surface of the guide roller (62). The anti-detachment mechanism (7) is set on the bridge bracket (61). The anti-detachment mechanism (7) includes two sets of connecting plates (71) symmetrically slidably mounted on the bridge bracket (61). Each set of connecting plates (71) is slidably connected to a sliding plate (72). The sliding plate (72) is equipped with a telescopic part (73) and a pressing roller (74). The pressing roller (74) is used to press the diaphragm in the cutting state and flatten it to both sides along the length of the diaphragm. The anti-detachment mechanism (7) also includes pressing blocks (75) symmetrically fixed on both sides of the spline rod (65), the pressing blocks (75) pressing against the connecting plate (71) when the spline rod (65) moves downward. Both sets of extrusion blocks (75) have wedge blocks (76) fixed on opposite sides, and wedge plates (77) are fixed on the slide plate (72). The surfaces of the wedge plates (77) and wedge blocks (76) that are in contact with each other are set as inclined surfaces to convert the vertical displacement of the spline rod (65) into the horizontal lateral movement of the slide plate (72).

2. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, The top end of the spline rod (65) is fixed with a handle (67), and a spring (68) is sleeved on the outside of the spline rod (65). The two ends of the spring (68) abut against the handle (67) and the sliding sleeve (64) respectively.

3. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, Each of the connecting plates (71) has a sliding limit rod (711) that is fixed on the bridge bracket (61). The limit rod (711) is provided with a second spring (712), and the two ends of the second spring (712) are fixed to the bridge bracket (61) and the connecting plate (71) respectively. A protrusion (713) is fixed on the limiting rod (711), and the lower surface of the protrusion (713) contacts the upper surface of the connecting plate (71).

4. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, The telescopic part (73) includes a plug rod (731) and a sleeve rod (732) slidably sleeved on the bottom end of the plug rod (731). A spring three (733) is provided on the outer surface of the plug rod (731). The two ends of the spring three (733) are fixed on the plug rod (731) and the sleeve rod (732) respectively. The pressing roller (74) is rotatably connected to the lower end of the sleeve rod (732) through a rotating shaft.

5. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 4, characterized in that, The insertion rod (731) and the sliding plate (72) are fixed together by a sliding rod (78). The connecting plate (71) is provided with a sliding groove (714) for sliding cooperation of the sliding rod (78). A spring (79) is fixed between the sliding rod (78) and the groove wall of the sliding groove (714).

6. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, The guide roller (62) has a negative pressure cavity (621) inside. Multiple sets of adsorption holes (622) are arranged in an axial and circumferential array on the roller surface of the guide roller (62). One end of the guide roller (62) is rotatably connected to an interface end (623) that is connected to an external negative pressure source.

7. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, A magnetic block one (631) is fixed to the inner wall of one end of the track (63), and a magnetic block two (641) is fixed to the side of the sliding sleeve (64) facing the magnetic block one (631). The magnetic block one (631) and the magnetic block two (641) form a magnetic attraction contact.

8. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, The extrusion block (75) is rotatably mounted with a roller (751) on the side facing the connecting plate (71).

9. The stretching and forming apparatus for producing polypropylene lithium battery separators according to claim 1, characterized in that, The outer circumferential surface of the pressing roller (74) is covered with a rubber layer.

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