Laser drilling machine for perforated foil of current collector of solid-state battery

Abstract

The invention discloses a laser drilling machine for a solid-state battery current collector perforated foil, and relates to the technical field of new energy battery manufacturing equipment, the laser drilling machine comprises a laser generating device, a foil conveying device and a supporting roller device located below the laser generating device; the supporting roller device comprises a horizontal center shaft and a plurality of supporting strips distributed in the peripheral direction of the center shaft in an array mode, the supporting strips can rotate relative to the center shaft and move in the radial direction of the center shaft at the same time, and all the supporting strips jointly form a cylindrical supporting face used for bearing the foil. The supporting roller device further comprises a switching assembly, and the switching assembly is used for driving the supporting strips to move so that the supporting strips can be circularly switched between the supporting state and the cleaning state in the rotating process. In the supporting state, the adjacent supporting strips abut against each other so that the foil can be supported in a closed mode. In a cleaning state, the adjacent supporting strips are separated from each other to discharge slag. The foil drilling device has the effect of improving the stability of foil drilling machining.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy battery manufacturing equipment, in particular to a laser drilling machine for solid-state battery current collector perforated foil. BACKGROUND

[0002] With the rapid development of new energy vehicles and energy storage technology, solid-state batteries have become the next generation of battery technology due to their high energy density and high safety. As a representative of the next generation of high-energy-density batteries, the core difficulty of solid-state batteries lies in the high contact resistance of solid-solid interface and the limited transmission efficiency of lithium ions in the electrode. The industry generally adopts micron-level array perforation processing on the ultra-thin aluminum foil or copper foil of the positive and negative electrode current collectors to make perforated foils, so as to increase the contact area of the electrode and the electrolyte, reduce the interface impedance, and improve the ion transmission efficiency. At the same time, perforation can also reduce the weight of the current collector without sacrificing mechanical strength, further improving the mass energy density of the battery.

[0003] The manufacturing of current collector perforated foil usually includes raw material smelting, calendering and thinning, surface cleaning, laser array drilling, and subsequent winding and coating processes. Among them, laser drilling is a key process that determines product quality. The existing laser drilling machine usually adopts a "roll-to-roll" continuous processing mode, and its core structure includes a unwinding unit, a tension control unit, a laser processing unit, and a winding unit. The foil is usually flattened by tension rollers and guided to the laser action area, and then pulled by the unwinding unit and the winding unit to realize continuous feeding.

[0004] When the existing laser perforation equipment uses high-energy pulsed laser to perforate the foil, if there is no support under the foil, the foil is easy to produce small but high-frequency vibration under the high-energy thermal impact of the laser, which can easily cause local deformation of the foil or irregular hole shape, affecting the perforation precision and consistency. If there is a support under the foil, the back microstructure may be damaged due to friction with the support surface, and molten material or perforation splashes may also accumulate on the lower support surface, affecting the stability and safety of subsequent continuous processing. SUMMARY

[0005] In order to solve the above problems, the present application provides a laser drilling machine for solid-state battery current collector perforated foil.

[0006] The present application provides a laser drilling machine for solid-state battery current collector perforated foil, which adopts the following technical scheme: A laser drilling machine for solid-state battery current collector perforated foil, comprising a laser generating device, a foil conveying device, and a support roller device located below the laser generating device; The support roller device comprises a horizontal central shaft and a plurality of support strips arranged in a peripheral array outside the central shaft, the support strips being capable of rotating relative to the central shaft while moving radially along the central shaft, and all the support strips collectively forming a cylindrical support surface for carrying the foil; The support roller device further comprises a switching assembly for driving the support strips to displace so as to cyclically switch the support strips between a supporting state and a cleaning state during rotation; In the supporting state, the adjacent support strips abut against each other to provide closed support for the foil; in the cleaning state, the adjacent support strips are separated from each other to discharge slag.

[0007] Optionally, the support strips are each provided with a plurality of interlocking teeth in a convex-concave staggered manner on the two side walls in contact with each other, in the supporting state, the interlocking teeth of the adjacent two support strips abut against and engage with each other to form a cylindrical support surface for the foil, and the interlocking teeth of the adjacent two support strips form a zigzag-shaped clearance at the engagement position, and the laser beam path of the laser generating device corresponds to the clearance.

[0008] Optionally, the switching assembly comprises an eccentric cam disc fixed to the two ends of the central shaft, and a plurality of follower rollers arranged on the outer walls of the support strips in the direction of the central shaft axis, the follower rollers corresponding to the support strips one by one, and the support strips keep the corresponding follower rollers always abutting against the profile surface of the eccentric cam disc through elastic return members; The profile surface of the eccentric cam disc is configured to have a first radial height in the interval corresponding to the supporting state, and a second radial height in the interval corresponding to the cleaning state, and the second radial height is greater than the first radial height, so that the support strips radially expand outward in the cleaning state to increase the circumferential spacing.

[0009] Optionally, end cover turntables are coaxially connected to the two ends of the central shaft, the eccentric cam disc is located inside the end cover turntables, and the two ends of the support strips are respectively connected to the inner walls of the two end cover turntables and reciprocally move along the radial direction of the central shaft.

[0010] Optionally, the width of the clearance is in the range of 0.1mm-0.3mm, and the tooth depth of the interlocking teeth is greater than 5 times the width of the clearance.

[0011] Optionally, the cleaning assembly is further arranged below the support roller device; The cleaning assembly is configured to intervene in the gap between the adjacent two support strips for contact scraping cleaning when the support strips are in the cleaning state and separated from each other.

[0012] Optionally, a rubbing device is arranged downstream of the support roller device in the foil conveying direction, the rubbing device comprising two differential rollers arranged in correspondence and at intervals, a gap between the two differential rollers for the foil to pass through, and the surface of the differential rollers is provided with a herringbone or spiral rubbing pattern for contact with the foil.

[0013] Optionally, a speed difference of 0.05%-0.5% is set between the linear speed of the two differential rollers and the conveying speed of the foil.

[0014] Optionally, the depth of the rubbing pattern on the surface of the differential rollers is less than 50% of the thickness of the foil.

[0015] In summary, the present application includes at least one of the following beneficial effects: 1. By arranging a support roller device below the laser generating device, the support strips distributed circumferentially around the outer periphery of the central shaft can switch back and forth between the support state and the cleaning state when the end caps rotate with the two ends of the central shaft, in the support state, the support strips corresponding to the rotation below the foil are close to each other, and the interlocking teeth on the side walls of the adjacent two support strips are tightly abutted and engaged with each other, thereby forming a cylindrical support surface that can provide stable support for the foil, so that the foil can remain stable when impacted by a high-energy laser beam and will not collapse under low-speed high heat, thereby effectively ensuring the quality of the foil punching, and at the same time, the interlocking teeth between the adjacent two interlocking teeth can form an avoidance gap for the laser beam to pass through, and the laser beam will pass through the interlocking teeth from the avoidance gap after passing through the foil, thereby avoiding damage to other areas on the back of the foil caused by the reflection of the laser beam after being shot at the interlocking teeth, in the cleaning state, the interlocking teeth are adjusted to a state of being separated from each other, and the separated interlocking teeth allow the cleaning assembly to intervene in the tooth gap, thereby facilitating deep cleaning of the metal slag deposited in the tooth gap. 2. The two differential rollers arranged in correspondence and at intervals have a linear speed slightly greater than the conveying speed of the foil, and the surface thereof is provided with a rubbing pattern, when the foil with a hole edge passes through the roller gap, due to the slight speed difference, the rubbing pattern on the surface of the roller will generate a micro-shearing force along the tangential direction on the surface of the foil, which is not enough to break the foil, but is enough to shovel down the hole edge vertically erected and press it into the base plane of the foil, and the divergent structure of the herringbone or spiral rubbing pattern to both sides will produce a weak transverse stretching effect on the foil, effectively releasing the thermal stress accumulated in the laser processing area, and effectively eliminating the lotus leaf edge phenomenon around the hole, thereby improving the hole quality. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structure schematic diagram of the laser drilling machine according to an embodiment of the present application; Figure 2is a sectional view of a foil conveying process according to an embodiment of the present application; Figure 3 is a structural schematic view of a tension adjusting assembly according to an embodiment of the present application; Figure 4 is a partial structural schematic view of a supporting roller device according to an embodiment of the present application; Figure 5 is Figure 4 is an enlarged schematic view at A; Figure 6 is a sectional view of a working principle of a supporting roller according to an embodiment of the present application; Figure 7 is a structural schematic view of a differential roller according to an embodiment of the present application.

[0017] Reference signs: 1, rack; 11, feeding transition roller; 12, discharging transition roller; 13, cleaning roller; 14, dust suction cover; 2, laser generating device; 3, foil conveying device; 31, unwinding assembly; 32, tension adjusting assembly; 33, winding assembly; 4, supporting roller device; 41, center shaft; 42, supporting strip; 421, finger-shaped fitting tooth; 422, clearance; 43, end cover turntable; 431, guide groove; 44, eccentric cam disc; 441, supporting section; 442, cleaning section; 443, transition section; 45, follow-up roller; 46, elastic recovery member; 5, foil; 6, rubbing device; 61, differential roller. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application.

[0019] The present application discloses a laser drilling machine for solid-state battery current collector perforated foil, referring to Figure 1 and Figure 2The laser drilling machine for solid-state battery current collector perforated foil comprises a frame 1, a laser generating device 2, a foil conveying device 3 and a supporting roller device 4 installed on the frame 1. The laser generating device 2 is used to emit a high-energy-density pulsed laser beam to continuously punch the current collector foil 5 in motion; the foil conveying device 3 is used to stably convey the foil 5 to ensure that it maintains constant tension and linear velocity during the punching process; and the supporting roller device 4 is used to provide rigid support for the foil 5 in the punching area to prevent the foil 5 from shaking and collapsing due to the lack of back support during laser punching.

[0020] It can be understood that, compared with directly punching the foil 5 in a suspended state, setting the supporting roller device 4 capable of providing stable support for the foil 5 at the position corresponding to the lower part of the punching area of the foil 5 can effectively reduce the shaking and collapse of the foil 5 in the suspended state, significantly improve the geometric accuracy and hole consistency of the punching position, and thus improve the overall quality stability of the perforated foil.

[0021] Illustratively, the frame 1 adopts a gantry structure as a whole to ensure high rigidity and stability, and the base of the frame 1 is preferably integrally cast from HT300 gray cast iron and is subjected to secondary annealing aging treatment to eliminate internal stress and prevent micro-deformation of the equipment during long-term operation. The supporting legs at the bottom of the frame 1 are fixed with shock-absorbing pads, which are preferably active air spring shock-absorbing feet, capable of effectively isolating the influence of low-frequency vibration of the workshop floor on the stability of the laser light path.

[0022] Illustratively, the laser generating device 2 comprises a fiber laser, a beam shaper and a laser galvanometer scanning system. The fiber laser is preferably a pulsed fiber laser with a MOPA (Master Oscillator Power Amplifier) architecture, and different laser wavelengths are selected for foils 5 of different materials, for example, 1064 nm wavelength is used for punching copper foil, and 532 nm frequency-doubled wavelength is used for punching aluminum foil to improve the absorption rate. The beam shaper is installed at the output end of the fiber laser to shape the Gaussian beam into a flat-top beam to ensure the neatness of the edge of the punched foil 5. The laser galvanometer scanning system preferably adopts a 3D dynamic focusing galvanometer system, and the pulse frequency of the laser and the conveying speed of the foil 5 are hard-synchronized through the encoder signal to ensure that the hole interval remains constant regardless of the acceleration or deceleration of the foil 5.

[0023] Illustratively, the foil conveying device 3 comprises an unwinding assembly 31, a tension adjusting assembly 32 and a winding assembly 33. Along the conveying direction of the foil 5, the unwinding assembly 31 and the winding assembly 33 are respectively arranged at both ends of the frame 1 to perform unwinding and winding operations on the foil 5, and the tension adjusting assembly 32 is arranged at the middle part of the frame 1 to monitor and adjust the tension change of the foil 5 in the conveying process in real time, so as to ensure that it maintains constant linear velocity and uniform tension in the punching area.

[0024] In some embodiments, the unwinding assembly 31 includes a cantilevered air expansion shaft and an unwinding motor. In order to adapt to the change of rotational inertia caused by different roll diameters, the unwinding motor preferably adopts a large-torque servo motor, and cooperates with an ultrasonic roll diameter sensor to monitor the change of roll diameter in real time. The control system of the machine tool calculates the dynamic torque compensation according to the real-time roll diameter, to ensure the smooth tension during unwinding start and stop. The tension adjusting assembly 32 preferably consists of a group of S-shaped foil-penetrating vacuum suction rollers. The surface of the vacuum suction roller is covered with micropores, and negative pressure is introduced inside. The tension is locked by increasing the friction between the foil 5 and the roller surface. The speed of all vacuum suction rollers is controlled by independent servo motors, and the tension fluctuation range is controlled within ±0.3N. The winding assembly 33 also adopts a cantilevered air expansion shaft. In order to prevent the occurrence of internal loose and external tight during winding, which may cause the collapse of the roll, the control system can use a taper tension control algorithm, that is, the winding tension decreases linearly or curvilinearly, for example, at a rate of 20%, as the roll diameter increases. In addition, a near-approaching pressure roller can be provided in front of the winding assembly 33. The near-approaching pressure roller is made of soft rubber and is always pressed against the cutting point of the winding roll. Its function is to exclude interlayer air and prevent interlayer slip of the foil 5 during high-speed winding, to ensure the neatness of the roll end face. The above laser generating device 2 and foil conveying device 3 are mature engineering modules in the existing technical field. The devices and principles used have been maturely used in industrial processing, so their specific structure and connection relationship do not need to be described here.

[0025] For example, referring to Figures 2 to 6 , the support roller device 4 includes a horizontally placed central shaft 41, which is located below the foil 5. The length of the central shaft 41 is greater than the width of the foil 5, and the axis direction of the central shaft 41 is perpendicular to the conveying direction of the foil 5. The two ends of the central shaft 41 are fixed to the machine frame 1, so that the central shaft 41 remains stationary relative to the machine frame 1. A plurality of support bars 42 are provided on the outer periphery of the central shaft 41. The support bars 42 are distributed circumferentially around the central shaft 41, and the length direction of each support bar 42 is parallel to the axis of the central shaft 41. In the embodiment of the present application, the number of support bars 42 is preferably 24. Since the support bars 42 are required to form a continuous support surface for the foil 5, the fewer the number of support bars 42, the more obvious the polygon effect, which may cause slight up-and-down vibration of the foil 5 during conveying. Too many support bars 42 will increase the structural complexity, and the accumulated assembly errors will also reduce the overall precision. The number of 24 support bars 42 achieves an optimal balance between structural complexity and continuous support.

[0026] In some embodiments, the two ends of the central shaft 41 are coaxially rotatably connected with an end cover turntable 43, the end cover turntable 43 can be directly driven to rotate by a direct drive torque motor, ensuring that the end cover turntable 43 has extremely high stability when rotating. The inner side wall of the end cover turntable 43 is provided with radially distributed guide grooves 431, the guide grooves 431 correspond to the support strips 42 one by one, and the two ends of each support strip 42 are respectively inserted and slidably connected in the corresponding guide groove 431, so that the support strip 42 can slide freely in the radial direction and be fixed in the circumferential direction, at this time each support strip 42 can rotate synchronously with the end cover turntable 43, and at the same time can move reciprocatingly in the radial direction along the guide groove 431. The support strip 42 can be cyclically switched between the supporting state and the cleaning state during the rotation process, in the supporting state, the support strips 42 closely arranged under the foil 5 form a continuous supporting surface, which can provide stable lifting force for the foil 5, preventing the foil 5 from sagging or trembling due to gravity or laser beam impact; in the cleaning state, as the end cover turntable 43 rotates, the closely arranged support strips 42 gradually separate from each other, exposing the gap between the support strips 42, which facilitates the removal of slag attached to the surface or gap of the support strips 42.

[0027] Further, in order to realize the automatic switching of the support strips 42 between the supporting state and the cleaning state, the two ends of the central shaft 41 are fixed with eccentric cam plates 44, the eccentric cam plates 44 are preferably made of bearing steel, and the surface is treated by carburizing and quenching to improve the surface hardness and wear resistance of the eccentric cam plates 44, ensuring the reliability of long-term operation. The contour line of the eccentric cam plate 44 is not a simple circle or ellipse, but is fitted by a plurality of function curves.

[0028] Specifically, as observed along the axis direction of the central shaft 41, the outer contour of the eccentric cam plate 44 includes a smooth transition curved surface-shaped supporting section 441, a cleaning section 442 and a transition section 443, wherein the supporting section 441 is a circular arc surface with a central angle of about 120 degrees, and is located in the ten o'clock to two o'clock direction of the central shaft 41, i.e. corresponding to the position close to the bottom surface of the foil 5 of the eccentric cam plate 44, the radius of the profile surface of the eccentric cam plate 44 corresponding to the supporting section 441 is defined as the first radial height; the cleaning section 442 is also a circular arc surface with a central angle of about 120 degrees, and is located in the four o'clock to eight o'clock direction of the eccentric cam plate 44 away from the bottom surface of the foil 5, the radius of the profile surface of the eccentric cam plate 44 corresponding to the cleaning section 442 is defined as the second radial height, it is worth noting that the second radial height is greater than the first radial height, the difference between the second radial height and the first radial height is set to 5-10mm, so that the support strips 42 radially expand outward in the cleaning state to increase the circumferential spacing. The transition section 443 smoothly connects the supporting section 441 and the cleaning section 442, and the curved surface is fitted by a high-order spline curve to ensure the smoothness when switching between the supporting section 441 and the cleaning section 442.

[0029] In some embodiments, the two side walls of the support strip 42 along the circumferential direction of the central shaft 41 are both processed into the convex-concave staggered finger-shaped interlocking teeth 421, i.e. trapezoidal tooth structure, by a wire cutting process. The outer wall of the support strip 42 towards the axis direction of the central shaft 41 is connected with a follower roller 45 through a connecting rod, the follower roller 45 corresponds to the support strip 42 one by one, and the outer edge of the follower roller 45 always keeps in contact with the outer contour surface of the eccentric cam disc 44, so that the support strip 42 can follow the contour change of the eccentric cam disc 44 in real time through the follower roller 45 to move reciprocatingly in the radial direction relative to the end cover turntable 43.

[0030] It can be understood that when the follower roller 45 rolls along the support section 441 of the eccentric cam disc 44, since the first radial height of the eccentric cam disc 44 at the support section 441 is the smallest, the support strip 42 shrinks inward under the driving of the follower roller 45, so that the support strips 42 at the support section 441 position are tightly fitted, the finger-shaped interlocking teeth 421 between the adjacent two support strips 42 abut and engage with each other, forming a continuous support surface; while when the follower roller 45 rolls along the cleaning section 442 of the eccentric cam disc 44, since the second radial height of the eccentric cam disc 44 at the cleaning section 442 is the largest, the support strip 42 expands outward under the driving of the follower roller 45, so that the finger-shaped interlocking teeth 421 between the adjacent support strips 42 at the cleaning section 442 position are disengaged from the engagement state, the circumferential distance between the adjacent two support strips 42 increases to form a gap, which facilitates the release or cleaning of the attachments in the tooth gap. In order to improve the structural strength and stability of the support strip 42, the support strip 42 is preferably made of invar alloy or high-strength die steel with extremely low thermal expansion coefficient, and the outer wall surface of the support strip is preferably covered with a layer of black alumina-titanium oxide composite ceramic coating by plasma spraying process. The black coating can effectively absorb the remaining laser energy penetrating through the foil 5 to prevent the reflected light from burning the back of the foil 5 again, and the ceramic material provides excellent wear resistance and heat insulation.

[0031] Further, in the support state, the interlocking finger-shaped interlocking teeth 421 form discontinuous and zigzag clearance gaps 422 at the engagement positions, the number and position of the clearance gaps 422 correspond to the laser beam emitted by the fiber laser for punching, so that the laser beam path for punching can be correspondingly shot to the clearance gaps 422. The width of the clearance gap 422 is in the range of 0.1mm-0.3mm, and the tooth depth of the finger-shaped interlocking tooth 421 is greater than 5 times the width of the clearance gap 422. The diameter of the laser beam spot for general processing is 20-50μm. During processing, the foil 5 is supported by the tooth surface of the finger-shaped interlocking tooth 421, and the processing laser beam passes through the zigzag clearance gap 422, so as to avoid the reflection of the laser beam after being shot to the tooth surface to cause damage to other areas of the back of the foil 5.

[0032] In some embodiments, to maintain the stable contact between the follower roller 45 and the outer profile surface of the eccentric cam disc 44, the end of the support strip 42 is provided with an elastic return member 46, which is preferably a compression spring. One end of the elastic return member 46 is fixed to the outer wall surface of the end of the support strip 42, and the other end is fixed to the inner wall of the corresponding guide groove 431 of the end cover disc 43. The elastic return member 46 is always in a compressed state, thereby exerting a continuous radial inward force on the support strip 42, ensuring that the follower roller 45 is always in close contact with the outer profile surface of the eccentric cam disc 44 and does not come off or jump during the rotation of the cam disc.

[0033] Further, the rack 1 is rotatably connected with an infeed transition roller 11 and an outfeed transition roller 12 of the same outer diameter at upstream and downstream positions corresponding to the central shaft 41, respectively. The axes of the infeed transition roller 11 and the outfeed transition roller 12 are parallel to the central shaft 41, and the axes of the infeed transition roller 11 and the outfeed transition roller 12 are at the same height. When the support strip 42 is in the supporting state, the bottom section of the infeed transition roller 11 is lower in vertical direction than the top section of the continuous support surface formed by the support strip 42. The foil 5 first passes under the infeed transition roller 11 and is wound around the continuous support surface formed by the support strip 42 in a tangential direction, and then is guided out from under the outfeed transition roller 12. The foil 5 forms an approximately semi-enclosed angle contact on the continuous support surface formed by the support strip 42, ensuring that the foil 5 only contacts the support strip 42 in the supporting state and is completely isolated from the mechanical disturbance caused by the periodic diameter change of the support strip 42. The conveying of the foil 5 and the periodic diameter change of the support strip 42 do not interfere with each other.

[0034] For example, to clean the support strip 42 in the separated state, the rack 1 is provided with a cleaning assembly below the central shaft 41. The cleaning assembly includes a cleaning roller 13 and a dust suction cover 14. The axis of the cleaning roller 13 is parallel to the central shaft 41. The cleaning roller 13 is rotatably connected to the rack 1, and the rotation direction is opposite to that of the end cover disc 43, so as to generate relative sliding friction. The surface of the cleaning roller 13 is covered with cleaning bristles, which can contact the support strip 42 in the cleaning state and extend into the gap between the support strips 42. The cleaning bristles are preferably made of conductive nylon 66, which effectively prevents static electricity accumulation and avoids dust adsorption. The dust suction cover 14 has the same length as the cleaning roller 13 and is located below the cleaning roller 13. The opening of the dust suction cover 14 is upward and faces the cleaning roller 13, which is used to suck the dust particles that fall off after the cleaning bristles rub against the support strip 42. The dust suction cover 14 can be connected to a dust suction device to realize centralized collection of dust.

[0035] Compared with other supports, the molten slag generated by laser perforation will splash and deposit in the avoidance groove of the support. Since the groove width on the conventional support is fixed and the groove depth is relatively deep, the molten slag accumulated at the bottom of the groove is prone to hardening after cooling. The conventional negative pressure wind force cannot completely suck out the molten slag. With the passage of time, the hardened waste slag will gradually fill the avoidance groove, eventually lifting up or even scratching the back of the foil 5, which seriously affects the yield of the perforated foil. In the cleaning state, the originally occluded finger-shaped interlocking teeth 421 are separated from each other, forming an open slag discharge gap with a width of more than 5 mm. The molten slag waste originally stuck in the zigzag gap loosens due to the loss of clamping force. The lower reverse rotating cleaning roller 13 is inserted into the open gap for cleaning, realizing complete self-cleaning.

[0036] For example, referring to Figure 2 and Figure 7 , along the foil 5 conveying direction, the rack 1 is provided with a rubbing device 6 downstream of the support roller device 4. The rubbing device 6 includes two differential rollers 61 arranged in an upper and lower correspondence and spaced apart. Both differential rollers 61 are horizontally connected to the rack 1. The linear speed of the two differential rollers 61 and the conveying speed of the foil 5 are set to have a speed difference of 0.05%-0.5%. The gap between the two differential rollers 61 is for the foil 5 to pass through. For example, in the control logic, the linear speed of the lower differential roller 61 is synchronized with the conveying speed of the foil 5, while the linear speed of the upper differential roller 61 is slightly greater than that of the lower differential roller 61. The difference between the linear speeds of the two is between 0.05%-0.5%.

[0037] Further, the surface of the differential roller 61 is processed with a chevron or spiral rubbing pattern by femtosecond laser etching process for contact with the foil 5. In the embodiments of the present application, spiral patterns are preferably processed. The depth of the rubbing pattern etched on the surface of the differential roller 61 is less than 50% of the thickness of the foil 5. Strictly speaking, it should be controlled within 30%-40% of the thickness of the foil 5, i.e. the etching depth of the rubbing pattern is controlled within 2-4 μm. The spiral angle of the rubbing pattern is 15-30° with respect to the axis, and is distributed in a diverging manner from the center of the roller body to both ends.

[0038] After the foil 5 is perforated by laser, a small amount of recast layer protrusion will inevitably occur at the edge of the hole, and due to local heating, there is residual thermal stress inside the foil 5, which is easy to cause the phenomenon of lotus leaf edge after winding. At this time, the upper and lower two differential rollers 61 are in contact with the surface of the foil 5 at the same time, and due to the existence of a small linear velocity difference between the two differential rollers 61, the small speed difference generates a shear friction force in opposite directions on the upper and lower surfaces of the foil 5. For a flat foil surface, due to the large contact area, the friction force is dispersed, but for the protruding hole flash, the shear force will concentrate, which can flatten or push down the protruding hole flash into the hole, thereby eliminating the anchor points of the interlayer hook. At the same time, the chevron pattern on the surface of the differential roller 61 cooperates with the small speed difference, which can generate a small amount of transverse component force on the foil 5 from the center to both sides. This force can effectively stretch the transverse wrinkles of the foil 5, release the thermal stress introduced by laser processing, and make the foil 5 restore flat before winding, further improving the quality of the foil 5 after processing. The frame 1 can also be provided with corresponding pressure adjusting mechanisms for the two differential rollers 61, and the pressure between the two rollers 61 is controlled by a gas cylinder or a servo motor. Through feedback such as grating ruler, the gap between the two rollers is locked at 6pm±0.5pm, avoiding excessive pressure on the foil 5 to cause plastic deformation.

[0039] The implementation principle of the solid-state battery current collector perforated foil laser drilling machine according to an embodiment of the present application is that a plurality of support strips 42 rotate synchronously with the end cover disc 43, and simultaneously make radial reciprocating sliding actions along the guide groove 431 on the inner wall of the end cover disc 43. In the rotating process, when the support strip 42 slides through the support section 441 profile surface of the eccentric cam disc 44 through the follow-up roller 45, the support strip 42 is pushed by the elastic return member 46 to move to the axis direction of the central shaft 41. At this time, the support strips 42 at the same support section 441 simultaneously shrink and gather to the axis direction of the central shaft 41, so that the finger-shaped interlocking teeth 421 on both sides of the support strip 42 are engaged with each other, forming a continuous support surface for the foil 5, ensuring the stable state of the foil 5 in the laser drilling process. When the support strip 42 rotates with the end cover disc 43 to the cleaning section 442 of the eccentric cam disc 44, all the support strips 42 at the cleaning section 442 expand and slide away from the axis direction of the central shaft 41. At this time, the adjacent support strips 42 are separated from each other to expose the gap, which is convenient for the cleaning roller 13 to clean the residual slag in the gap.

[0040] In the description of the present application, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0041] The embodiments, implementation manners and related technical features of the present application can be combined with each other without conflict.

[0042] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application without departing from the technical solution content of the present application still falls within the scope of the technical solution of the present application.

Claims

1. A laser drill for solid state battery current collector perforated foil, characterized by: The utility model relates to a laser foil cleaning device, comprising a laser generating device (2), a foil conveying device (3) and a supporting roller device (4) below the laser generating device (2). The supporting roller device (4) comprises a horizontal central shaft (41) and a plurality of supporting strips (42) arranged in a circumferential array outside the central shaft (41), the supporting strips (42) can rotate relative to the central shaft (41) while moving radially along the central shaft (41), and all the supporting strips (42) together form a cylindrical supporting surface for carrying the foil (5). The supporting roller device (4) further comprises a switching assembly for driving the supporting strips (42) to displace so that the supporting strips (42) are cyclically switched between a supporting state and a cleaning state during rotation. In the supporting state, the adjacent supporting strips (42) abut against each other to provide closed support for the foil (5); in the cleaning state, the adjacent supporting strips (42) are separated from each other to discharge slag. The supporting strips (42) are provided with interlocking teeth (421) in a convex-concave staggered manner on both sides of the two side walls in contact with each other, in the supporting state, the interlocking teeth (421) of the adjacent two supporting strips (42) abut against and engage with each other to form a cylindrical supporting surface for the foil (5), and the interlocking teeth (421) of the adjacent two supporting strips (42) form a zigzag clearance (422) at the engagement position, and the laser beam path of the laser generating device (2) corresponds to the clearance (422).

2. The solid-state battery current collector perforation foil laser drill of claim 1, wherein: The switching assembly comprises an eccentric cam disc (44) fixed to both ends of the central shaft (41), and a follower roller (45) arranged on the outer wall of the supporting strip (42) in the direction of the central shaft (41) axis, the follower roller (45) corresponds to the supporting strip (42), and the supporting strip (42) keeps the corresponding follower roller (45) always abutting against the profile surface of the eccentric cam disc (44) through an elastic return member.

3. The solid-state battery current collector perforation foil laser drill of claim 2, wherein: The profile surface of the eccentric cam disc (44) is configured to have a first radial height in the interval corresponding to the supporting state, and a second radial height in the interval corresponding to the cleaning state, and the second radial height is greater than the first radial height, so that the supporting strips (42) radially expand outward in the cleaning state to increase the circumferential spacing. Both ends of the central shaft (41) are coaxially connected with an end cover turntable (43), the eccentric cam disc (44) is located inside the end cover turntable (43), and both ends of the supporting strip (42) are respectively connected to the inner walls of the two end cover turntables (43) in a sliding manner and reciprocate along the radial direction of the central shaft (41).

4. The solid-state battery current collector perforation foil laser drill of claim 3, wherein: The width of the clearance (422) is 0.1mm-0.3mm, and the tooth depth of the interlocking teeth (421) is greater than 5 times the width of the clearance (422).

5. The solid-state battery current collector perforation foil laser drill of claim 2, wherein: The utility model further comprises a cleaning assembly arranged below the supporting roller device (4).

6. The solid-state battery current collector perforation foil laser drill of claim 1, wherein: The cleaning assembly is configured to intervene in the gap between the adjacent two supporting strips (42) for contact scraping cleaning when the supporting strips (42) are in the cleaning state and separated from each other. ​ 7. The solid-state battery current collector perforation foil laser drill of claim 1, wherein: Downstream of the support roller device (4) in the conveying direction of the foil (5), a rubbing device (6) is arranged, the rubbing device (6) comprising two differential rollers (61) arranged in an upper and lower correspondence and in a spaced manner, a gap between the two differential rollers (61) being used for the foil (5) to pass through, and the surface of the differential rollers (61) being processed with a herringbone or spiral rubbing pattern for contacting the foil (5).

8. The laser drill according to claim 7, characterized in that A speed difference of 0.05%-0.5% is set between the linear speed of the two differential rollers (61) and the conveying speed of the foil (5).

9. The laser drill according to claim 7, wherein, The depth of the rubbing pattern arranged on the surface of the differential rollers (61) is less than 50% of the thickness of the foil (5).

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