Ultrathin metal lithium strip production system and production method

Abstract

The invention relates to the technical field of lithium strip production equipment, and discloses an ultrathin metal lithium strip production system and a production method. The production system comprises an extrusion system, a tension control mechanism, a rolling mill, a winding roller and an isolating membrane unwinding mechanism which are sequentially arranged on a production line, and a plurality of guide rollers which are arranged along the production line and are used for supporting lithium strips; the tension control mechanism comprises a tension control roller and an angle encoder matched with the tension control roller; the angle encoder is configured to be in communication connection with the extrusion system, the angle of the angle encoder is adjusted in real time so that the tension control roller can move in a matched mode, the pressure, from the lithium strip, borne by the tension control roller can be a preset value, and when the angle of the angle encoder exceeds a threshold value, the angle encoder feeds back a signal to the extrusion system. The extrusion system is configured to adjust the extrusion speed upon receiving the angle encoder signal. By means of the device, efficient production of the metal lithium strip can be achieved, and waste caused by threading can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ribbon production equipment, and in particular to an ultra-thin metal lithium ribbon production system and a production method. Background Art

[0002] In recent years, the research on solid-state batteries has gradually increased. Whether it is universities, research institutes or enterprises, they have kept up with the pace of the industry and updated the research progress of solid-state batteries in real time. Solid-state batteries are not achieved overnight. In the transition stage, they can be divided into semi-solid batteries (electrolyte accounts for 5-10%), quasi-solid batteries (electrolyte accounts for 0-5%), and all-solid batteries (electrolyte accounts for 0%) according to the electrolyte content. At present, all-solid-state batteries have not yet been applied in the terminal market. The main reason is that there are still many difficulties on the electrolyte and negative electrode sides that have not been completely overcome. On the negative electrode side, metallic lithium is considered to be the most promising next-generation lithium battery negative electrode material due to its extremely low redox potential (-3.04V Vs.SHE) and extremely high specific capacity (3860mAh / g). Metallic lithium as a negative electrode material was first widely studied in the field of lithium primary batteries. In the field of secondary batteries, because its safety has not been solved, the intercalated structure negative electrode material replaced the lithium metal negative electrode for rechargeable lithium-ion batteries. Today, with the development of key material technologies for lithium-ion batteries, lithium metal negative electrodes have once again been pushed onto the historical stage. Unlike lithium metal primary batteries that require a large amount of lithium, lithium metal secondary batteries contain a lithium source on the positive electrode side, and only a small amount of lithium source is needed on the negative electrode side to maintain sufficient lithium supply throughout the battery life cycle. Therefore, the traditional 100-micron-level metal lithium belt is no longer suitable for high-energy-density lithium metal secondary batteries. In theory, for lithium metal secondary batteries, the thinner the negative electrode lithium belt, the more obvious the improvement in energy density. For example, the use of 20μm ultra-thin metal lithium belt can easily increase the energy density of the battery cell to more than 400Wh / kg. For this reason, the development of 20μm ultra-thin metal lithium belts and their large-scale and efficient preparation are of great significance to the development of the next generation of lithium metal batteries. At present, a few companies at home and abroad have the ability to produce and prepare 20μm ultra-thin metal lithium belts. The process route is almost a two-step method, that is, first hydraulically extruding a 100-micron-thick lithium belt, and then thinning it by calendering. The above method requires winding and threading. This process not only wastes a large amount of lithium belts, but also greatly reduces production efficiency.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The object of the present invention is to provide a production system and a production method for an ultra-thin metal lithium strip.

[0005] The present invention is achieved in that:

[0006] In a first aspect, the present invention provides an ultra-thin lithium metal strip production system, comprising: an extrusion system, a first tension control mechanism, a rolling mill and a winding roller, a separator unwinding mechanism, and a plurality of guide rollers for supporting lithium strips arranged along the production line in sequence;

[0007] A lithium strip forming die is provided at the discharge port of the extrusion system;

[0008] The first tension control mechanism includes a first tension control roller and a first angle encoder arranged in cooperation with the first tension control roller;

[0009] The first angle encoder is configured to be connected to the extrusion system for communication, and the angle of the first angle encoder is adjusted in real time to make the first tension control roller move in coordination so that the pressure from the lithium belt on the first tension control roller is a first preset value. When the angle of the first angle encoder exceeds a first threshold value, the first angle encoder feeds back a signal to the extrusion system, and the extrusion system is configured to adjust the extrusion speed after receiving the first angle encoder signal.

[0010] Alternatively, the first angle encoder is configured to be connected to the rolling mill for communication, and the angle of the first angle encoder is adjusted in real time so that the first tension control roller moves in coordination so that the pressure from the lithium strip on the first tension control roller is a first preset value, and when the angle of the first angle encoder exceeds a first threshold value, the first angle encoder feeds back a signal to the rolling mill, and the rolling mill is configured to adjust the rolling speed after receiving the signal from the first angle encoder;

[0011] During operation, the lithium ribbon extruded by the extrusion system and the forming die is successively wound onto the winding roller through the first tension control mechanism and the rolling mill; the isolation film is continuously unwound by the unwinding mechanism and wound onto the winding roller together with the lithium ribbon.

[0012] In an optional embodiment, the production system further comprises a second tension control mechanism, the second tension control mechanism being located between the rolling mill and the winding roller;

[0013] The second tension control mechanism includes a second tension control roller and a second angle encoder arranged in cooperation with the second tension control roller;

[0014] The second angular encoder is configured to communicate with the winding roller, and the angle of the second angular encoder is adjusted in real time so that the second tension control roller moves in coordination so that the pressure from the lithium belt received by the second tension control roller is a second preset value. When the angle of the second angular encoder exceeds the second threshold value, the second angular encoder feeds back a signal to the winding roller, and the winding roller is configured to adjust the winding speed after receiving the second angular encoder signal.

[0015] In an optional embodiment, the isolation film unwinding mechanism includes an unwinding roller and a third tension control mechanism;

[0016] The third tension control mechanism includes a third tension control roller and a third angle encoder arranged in cooperation with the third tension control roller;

[0017] The third angle encoder is configured to communicate with the unwinding roller, and the angle of the third angle encoder is adjusted in real time so that the third tension control roller moves in coordination so that the pressure exerted on the third tension control roller from the isolation film is a third preset value. When the angle of the third angle encoder exceeds the third threshold value, the third angle encoder feeds back a signal to the unwinding roller, and the unwinding roller is configured to adjust the winding speed after receiving the third angle encoder signal.

[0018] In an optional embodiment, the extrusion system includes an extruder, a servo hydraulic pump and a speed sensor, the extruder includes an extrusion barrel for containing lithium material, a push head arranged in the extrusion barrel for extruding the lithium material toward the forming die, a hydraulic push rod connected to the push head, and a hydraulic cylinder connected to the extrusion barrel for moving the push head, the hydraulic cylinder is connected to a servo hydraulic pump for pumping hydraulic oil therein, and the speed sensor is arranged at one end of the hydraulic push rod away from the push head;

[0019] The production system further includes a control system, a first speed measuring roller, a first thickness measuring device, a second thickness measuring device and a second speed measuring roller; the first speed measuring roller is located between the extrusion system and the first tension control mechanism, the first thickness measuring device is located between the first tension control mechanism and the rolling mill, and the second speed measuring roller and the second thickness measuring device are located between the rolling mill and the winding roller;

[0020] The control system is in communication connection with the servo hydraulic pump, the first speed measuring roller, the second speed measuring roller, the first thickness measuring device and the second thickness measuring device. The control system has a built-in formula:

[0021]

[0022] Wherein, Q is the flow rate of the hydraulic cylinder, D is the inner diameter of the extrusion barrel, V0 is the speed of the push head, V1 is the speed of the extruded lithium strip, V2 is the speed of the rolled lithium strip, T1 is the thickness of the extruded lithium strip measured by the first thickness measuring device, T2 is the thickness of the rolled lithium strip measured by the second thickness measuring device, and W is the width of the lithium strip;

[0023] Set any value among Q, V0, V1 and V2, and calculate the other three values ​​through the formula. Compare the calculated value with the value of actual detection feedback. The control system adjusts the hydraulic cylinder liquid flow rate or the rolling lithium belt speed according to the comparison result to make the calculated result consistent with the actual measured result;

[0024] Optionally, the inner diameter of the extrusion barrel is 150-700 mm, the wall thickness is 20-100 mm, and the length is 300-1000 mm.

[0025] In an optional embodiment, the production system further includes a deviation correction control mechanism, which is disposed between the first tension control mechanism and the second thickness measuring device, and includes a deviation correction sensor disposed in front and a deviation correction guide roller group disposed in the rear.

[0026] In an optional embodiment, the production system further comprises a bonding roller, wherein the bonding roller is located between the second tension control mechanism and the winding roller;

[0027] During operation, the lithium ribbon extruded by the extrusion system and the forming die is successively wound onto the winding roller through the first speed measuring roller, the first tension control mechanism, the deviation correction control mechanism, the first thickness measuring device, the rolling mill, the second thickness measuring device, the second speed measuring roller, the second tension control mechanism and the combining roller; the isolation film wound on the unwinding roller is continuously unwound and wound onto the winding roller together with the lithium ribbon through the third tension control mechanism and the combining roller.

[0028] In an optional embodiment, the winding roller and / or the unwinding roller is an inflatable shaft with a length of 300 to 800 mm.

[0029] In an optional embodiment, the rolling mill includes a pair of backing rolls and a pair of working rolls symmetrically arranged, the pair of working rolls are located between the pair of backing rolls, and the gap between the working rolls is the rolling gap;

[0030] Optionally, the diameter of each backing roller is 100 to 500 mm;

[0031] Optionally, the diameter of each working roll is 50 to 300 mm;

[0032] Optionally, the length of the backing roller and / or the working roller is 200 to 700 mm;

[0033] Optionally, the backing roller and the working roller have a surface finish of Ra≤0.5 μm and a hardness of RHC≥50 degrees.

[0034] In an optional embodiment, the guide roller has a diameter of 50 to 150 mm, a length of 200 to 700 mm, a surface finish of Ra ≤ 0.2 μm, and a hardness of RHC ≥ 50 degrees.

[0035] In a second aspect, the present invention provides a method for producing a lithium strip, which is implemented using a production system as described in any of the aforementioned embodiments.

[0036] The present invention has the following beneficial effects:

[0037] The ultra-thin lithium metal strip production system provided by the present invention combines extrusion and rolling together, and the combination of the two needs to ensure that the extrusion and rolling speeds match in order to ensure production quality; in the production system of the present invention, a first angular encoder is configured to communicate with an extruder or a rolling mill and feedback a signal, and the extrusion speed of the extruder or the rolling speed of the rolling mill is adjusted according to the signal fed back by the angular encoder to ensure that the extrusion speed and the rolling speed match, thereby achieving efficient production of lithium metal strips. The combination of extrusion and rolling to manufacture lithium strips can also reduce waste caused by threading. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic structural diagram of an ultra-thin lithium strip production system provided in an embodiment of the present invention.

[0040] Icons: 1-extruder; 2-molding die; 3-rolling mill; 10-lithium strip before the rolling mill entrance; 11-lithium strip after the rolling mill exit; 12-isolation film; 100-guide roller; 101-hydraulic cylinder; 102-hydraulic push rod; 103-push head; 105-extrusion barrel; 311-first speed measuring roller; 321-first tension control mechanism; 331-correction sensor; 332-correction guide roller group; 341-first thickness measuring device; 401-back-up roller; 411-working roller; 511-second thickness measuring device; 521-second speed measuring roller; 531-second tension control mechanism; 532-third tension control mechanism; 533-combining roller; 541-winding roller; 551-unwinding roller. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0042] The following is a detailed description of the ultra-thin lithium metal strip production system and method improved by the embodiments of the present invention.

[0043] like Figure 1As shown, an ultra-thin metal lithium strip production system provided by an embodiment of the present invention comprises: an extrusion system, a first tension control mechanism 321, a rolling mill 3 and a winding roller 541, a separator 12 unwinding mechanism, and a plurality of guide rollers 100 for supporting a lithium strip 11 arranged along the production line in sequence;

[0044] A lithium strip forming die 2 is provided at the discharge port of the extrusion system;

[0045] The first tension control mechanism 321 includes a first tension control roller and a first angle encoder arranged in cooperation therewith;

[0046] The first angle encoder is configured to be connected to the extrusion system for communication, and the angle of the first angle encoder is adjusted in real time so that the first tension control roller moves in coordination so that the pressure from the lithium belt 11 received by the first tension control roller is a first preset value. When the angle of the first angle encoder exceeds a first threshold value, the first angle encoder feeds back a signal to the extrusion system, and the extrusion system is configured to adjust the extrusion speed after receiving the first angle encoder signal.

[0047] For example, the standard value of the first angular encoder is set to 0°, the first threshold is ±1°, and the corresponding length space of the lithium belt 10 is adjusted to ±0.4m. Usually, in order to ensure that the pressure value of the first tension control roller is the first preset value, the first angular encoder will fluctuate within the range of ±1°. When the angle of the first angular encoder changes by more than +1° in order to ensure that the pressure value of the first tension control roller is the first preset value, it will feed back a signal to the extrusion system, and the extrusion system will reduce the extrusion speed to an appropriate size; when the angle of the first angular encoder changes to less than -1°, it will feed back a signal to the extrusion system, and the extrusion system will increase the extrusion speed.

[0048] Alternatively, the first angle encoder is configured to be connected to the rolling mill 3 for communication, and the angle of the first angle encoder is adjusted in real time so that the first tension control roller moves in coordination so that the pressure from the lithium strip 10 received by the first tension control roller is a first preset value, and when the angle of the first angle encoder exceeds a first threshold value, the first angle encoder feeds back a signal to the rolling mill 3, and the rolling mill 3 is configured to adjust the rolling speed after receiving the first angle encoder signal;

[0049] For example, the standard value of the first angle encoder is set to 0°, the first threshold is ±1, and the corresponding length space of the lithium belt 10 is adjusted to ±0.4m. Usually, in order to ensure that the pressure value of the first tension control roller is the first preset value, the first angle encoder will fluctuate within the range of ±1. When the angle of the first angle encoder changes by more than +1 in order to ensure that the pressure value of the first tension control roller is the first preset value, it will feed back a signal to the rolling mill 3, and the rolling mill 3 will increase the rolling speed to an appropriate size; when the angle of the first angle encoder changes to less than -1, it will feed back a signal to the rolling mill 3, and the rolling mill 3 will increase the rolling speed.

[0050] During operation, the lithium strip 10 extruded by the extrusion system and the forming die is successively wound onto the winding roller 541 through the first tension control mechanism 321 and the rolling mill 3 ; the isolation film 12 is continuously unwound by the unwinding mechanism and wound onto the winding roller 541 together with the lithium strip 11 .

[0051] The ultra-thin lithium metal strip production system provided by the present invention combines extrusion and rolling together, and the combination of the two needs to ensure that the extrusion and rolling speeds match in order to ensure production quality; in the production system of the present invention, a first angular encoder is configured to communicate with the extruder 1 or the rolling mill 3 and feedback a signal, and the extrusion speed of the extruder 1 or the rolling speed of the rolling mill 3 is adjusted according to the signal fed back by the angular encoder to ensure that the extrusion speed matches the rolling speed, thereby achieving efficient production of the lithium metal strip 11. The combination of extrusion and rolling to manufacture the lithium strip 11 can also reduce waste caused by threading.

[0052] Optionally, the lithium ribbon prepared by the ultra-thin metal lithium ribbon production system provided by the embodiment of the present invention may be a pure lithium ribbon or a lithium alloy ribbon.

[0053] Optionally, the extrusion system includes an extruder 1, a servo hydraulic pump (not shown) and a speed sensor (not shown), wherein the extruder 1 includes an extrusion barrel 105 for accommodating lithium material, a push head 103 disposed in the extrusion barrel 105 for extruding lithium material toward the lithium strip forming die 2, a hydraulic push rod 102 connected to the push head 103, and a hydraulic cylinder 101 connected to the extrusion barrel 105 for moving the push head 103, the hydraulic cylinder 101 is connected to a servo hydraulic pump for pumping hydraulic oil therein, and the speed sensor is disposed at one end of the hydraulic push rod 102 away from the push head 103. The speed sensor is used to detect the displacement and speed of the hydraulic rod 102.

[0054] Optionally, the extrusion force of the extrusion system is 300 to 1500 tons.

[0055] Optionally, the hydraulic cylinder 101 is connected to a servo hydraulic pump (not shown) for pumping hydraulic oil therein, and the flow rate of the servo hydraulic pump injected into the hydraulic cylinder 101 can be adjusted by controlling the rotation speed of the servo hydraulic pump.

[0056] Optionally, the inner diameter of the extrusion barrel 105 is 150-700 mm, the wall thickness is 20-100 mm, the length is 300-1000 mm, and the material is high wear-resistant steel such as manganese alloy steel and chrome alloy steel, and the inner surface finish Ra≤0.2 μm.

[0057] Optionally, the gap between the push head 103 and the extrusion barrel 105 is 0-0.2 mm.

[0058] Optionally, a hydraulic push rod 102 is provided in the hydraulic cylinder 101 , one end of the hydraulic push rod 102 is connected to the push head 103 , the clearance between the diameter of the hydraulic push rod and the extrusion barrel 105 is 10 to 30 mm, and the length of the hydraulic push rod 102 is greater than the length of the extrusion barrel 105 .

[0059] Specifically, a guide roller 100 is arranged behind the forming die, and the guide roller 100 is used to support the lithium strip 11; a first speed measuring roller 311 is arranged behind the guide roller 100, and the first speed measuring roller 311 is used to detect the speed of the lithium strip 10 extruded from the forming die; a first tension control mechanism 321 is arranged behind the first speed measuring roller 311, and the first tension control mechanism 321 is used to control the tension of the extruded lithium strip 10 to a first preset value; a deviation correction control mechanism is arranged behind the first tension control mechanism 321, and is used to ensure that the lithium strip 10 does not deviate on the production line; a first thickness measuring device 341 is arranged behind the deviation correction control mechanism, and is used to detect the thickness of the extruded lithium strip 10; a plurality of guide rollers 100 are arranged behind the first thickness measuring device 341, and are used to support A lithium strip 10 is supported; a rolling mill 3 is arranged after a plurality of guide rollers 100, for rolling the extruded lithium strip 10 to a target thickness; a plurality of guide rollers 100 are arranged after the rolling mill 3; a second thickness measuring device 511 is arranged after the plurality of guide rollers 100, for detecting the thickness of the lithium strip 11 after rolling; a second speed measuring roller 521 is arranged after the second thickness measuring device 511, for detecting the speed of the lithium strip 11 output after rolling; a second tension control mechanism 531 is arranged after the second speed measuring roller 521, for controlling the tension of the lithium strip 11 after rolling to a second preset value; a coupling roller 533 is arranged after the second tension control mechanism 531, and a winding roller 541 is arranged after the coupling roller 533, and the lithium strip 11 is wound up by the winding roller 541 after the coupling roller 533.

[0060] The unwinding mechanism includes a third tension control mechanism 532 and an unwinding roller 551. The unwinding roller 551 is rolled up with an isolation film 12. During operation, the isolation film 12 is unwound through the third tension control mechanism 532 to reach the combining roller 533 to overlap with the lithium tape 11 and is finally rolled up by the winding roller 541. The third tension control mechanism 532 is used to control the tension of the unwound isolation film 12 to a third preset value.

[0061] Optionally, the measuring range of the first speed measuring roller 311 and the second speed measuring roller 521 is 0-100 m / min, and the higher the accuracy, the better.

[0062] Optionally, the control algorithm of the first tension control mechanism 321 for feedback-adjusting the extrusion system is a PID closed-loop control algorithm. Further, the first angle encoder is specifically connected to the servo hydraulic pump of the extrusion system for communication.

[0063] Optionally, the deflection correction control mechanism includes a deflection correction sensor 331 disposed in front and a deflection correction guide roller group 332 disposed in the back. The deflection correction sensor 331 detects whether the lithium belt 10 is deflected. If deflection occurs, the deflection correction guide roller group 332 adjusts the lithium belt 10 to return to the correct position.

[0064] Optionally, the correction sensor 331 is an infrared sensor or an ultrasonic sensor, and the higher the correction accuracy, the better, generally ±0.1 mm, for example.

[0065] Optionally, the first thickness measuring device 341 can move in the transverse direction of the lithium strip 10 (perpendicular to the length direction of the lithium strip 10) to scan the transverse thickness of the lithium strip 10, and use the average value of the scanned thickness as the measurement value T1. Specifically, the thickness measuring device has a measurement range of 0.05 to 3 mm, and the higher the accuracy, the better, for example, 0.001 mm.

[0066] Optionally, the measurement range of the second thickness measuring device 511 is 0.005-0.2 mm, and the higher the accuracy, the higher the accuracy, for example, it can be 0.0005 mm. The second thickness measuring device 511 is used to measure the thickness T2 of the lithium strip 11 after rolling, and the second side thickness device is fixed in the transverse center area of ​​the lithium strip 11 to measure the longitudinal thickness trend (parallel to the length direction of the lithium strip 11) of the same point.

[0067] Optionally, the rolling mill 3 includes a pair of back-up rollers 401 and a pair of working rollers 411 that are symmetrically arranged, the pair of working rollers 411 are located between the pair of back-up rollers 401, and the gap between the working rollers 411 is a rolling gap.

[0068] Optionally, the diameter of each backing roller 401 is 100-500 mm; the diameter of each working roller 411 is 50-300 mm; the length of the backing roller 401 and / or the working roller 411 is 200-700 mm. The roller material is wear-resistant steel such as manganese alloy steel, chromium alloy steel, etc., with a hardness of HRC 50-80 degrees.

[0069] The manual mode of rolling mill 3 is to manually adjust the roll gap T4, and the automatic mode is to automatically adjust the roll gap T4 by calculating the difference between the measured thickness T2 and the target thickness T3 until |T2-T3|≤2μm. The starting condition of the automatic mode is that the fluctuation of the measured value T2 is less than ±2μm, the linear speed of the working roll 411 is 0≤V2≤120m / min, and the acceleration is 0.5m / s.

[0070] Optionally, the second tension control mechanism 531 includes a second tension control roller and a second angle encoder arranged in cooperation therewith;

[0071] The second angular encoder is configured to communicate with the winding roller 541, and the angle of the second angular encoder is adjusted in real time so that the second tension control roller moves in coordination so that the pressure from the lithium belt 11 received by the second tension control roller is a second preset value. When the angle of the second angular encoder exceeds the second threshold value, the second angular encoder feeds back a signal to the winding roller 541. The winding roller 541 is configured to adjust the winding speed after receiving the second angular encoder signal.

[0072] For example, the standard value of the second angular encoder is set to 0°, the second threshold value is ±1°, and the corresponding length space of the lithium tape 11 is adjusted to ±0.4m. Usually, in order to ensure that the pressure value of the second tension control roller is the second preset value, the second angular encoder will fluctuate within the range of ±1°. When the angle of the second angular encoder changes by more than +1° in order to ensure that the pressure value of the second tension control roller is the first preset value, it will feed back a signal to the winding roller 541, and the winding roller 541 will increase the winding speed to an appropriate size; when the angle of the second angular encoder changes to less than -1°, it will feed back a signal to the winding roller 541, and the winding roller 541 will reduce the winding speed.

[0073] Specifically, the winding roller 541 includes a roller body and a servo motor for driving the roller body to move, and the second angle encoder is in communication connection with the servo motor. The second angle encoder sends a signal to the servo motor, and the servo motor adjusts the rotation speed of the roller body after receiving the signal.

[0074] By making the second angular encoder automatically adjust the speed of the winding roller 541, the rolled lithium strip has a stable winding speed.

[0075] Optionally, the third tension control mechanism 532 includes a third tension control roller and a third angle encoder arranged in cooperation therewith;

[0076] The third angle encoder is configured to communicate with the unwinding roller 551, and the angle of the third angle encoder is adjusted in real time so that the third tension control roller moves in coordination so that the pressure exerted on the third tension control roller from the isolation film 12 is a third preset value. When the angle of the third angle encoder exceeds the third threshold value, the third angle encoder feeds back a signal to the unwinding roller 551, and the unwinding roller 551 is configured to adjust the winding speed after receiving the third angle encoder signal.

[0077] For example, the standard value of the third angle encoder is set to 0°, the third threshold value is ±1°, and the corresponding length space of the lithium tape 11 is adjusted to ±0.4m. Usually, in order to ensure that the pressure value of the third tension control roller is the third preset value, the third angle encoder will fluctuate within the range of ±1°. When the angle of the third angle encoder changes by more than +1° in order to ensure that the pressure value of the third tension control roller is the third preset value, it will feed back a signal to the unwinding roller 551, and the unwinding roller 551 will reduce the unwinding speed to an appropriate size; when the angle of the third angle encoder changes to less than -1°, it will feed back a signal to the unwinding roller 551, and the unwinding roller 551 will reduce the extrusion speed.

[0078] Optionally, the production system further includes a control system; the control system is in communication connection with the servo hydraulic pump, the first speed measuring roller 311, the second speed measuring roller 521, the first thickness measuring device 341 and the second thickness measuring device 511, and the control system has a built-in formula:

[0079] Wherein, Q is the liquid inlet flow of the hydraulic cylinder 101, D is the inner diameter of the extrusion barrel 105, V0 is the speed of the push head 103, V1 is the speed of the extruded lithium strip 10, V2 is the speed of the rolled lithium strip 11, T1 is the thickness of the extruded lithium strip 10 measured by the first thickness measuring device 341, T2 is the thickness of the rolled lithium strip 11 measured by the second thickness measuring device 511, and W is the width of the lithium strip 11;

[0080] By setting any value of Q, V0, V1 and V2, the other three values ​​can be calculated by the formula, and the calculated value is compared with the value of the actual detection feedback. The control system adjusts the liquid flow rate of the hydraulic cylinder 101 or the speed of the rolling lithium belt 11 according to the comparison result to make the calculated result consistent with the actual measured result. Since the speed of the push head is the same as the speed of the hydraulic push rod, the actual value of V0 can be measured by the speed sensor.

[0081] When the production system also includes the above-mentioned speed adjustment mode, the efficiency of the production of the lithium strip 11 can be further improved and the production quality can be guaranteed.

[0082] Optionally, the guide roller 100 has a diameter of 50 to 150 mm, a length of 200 to 700 mm, a surface finish of Ra ≤ 0.2 μm, and a hardness of RHC ≥ 50 degrees.

[0083] The embodiment of the present invention further provides a method for producing a lithium strip 11, which is implemented using the production system provided by the embodiment of the present invention.

[0084] The specific process of the production method includes:

[0085] When working, put the metal lithium ingot into the extrusion barrel 105, start the extruder 1 in manual mode to extrude the metal lithium so that it passes through the lithium strip forming die 2 to extrude the lithium strip 10, and the lithium strip 10 is sequentially passed through the first speed measuring roller 311, the first tension control mechanism 321, the deviation correction control mechanism, the first thickness measuring device 341, the rolling mill 3, the second thickness measuring device 511, the second speed measuring roller 521, the second tension control mechanism 531 and the bonding roller 533 to be fixed on the winding roller 541. At the same time, the isolation film 12 wound on the unwinding roller 551 is sequentially passed through the third tension control mechanism 532 and the bonding roller 533 to be fixed on the winding roller 541;

[0086] After the strip is threaded, stop manual extrusion and set the extruder 1 to automatic mode. Set the preset values ​​of the first tension control mechanism 321, the second tension control mechanism 531 and the third tension control mechanism 532 to F1, F2 and F3 respectively, set the initial rolling speed V2 of the rolling mill 3 to 1m / min, set the roll gap T4 of the working roll 411 to 30μm, and set the target thickness T3 of the lithium strip 11 to 30μm. Start the rolling mill 3 in manual mode, press down after the roller linear speed reaches the set value V2, when the working roll 411 contacts the lithium strip 10, under the action of friction, the lithium strip 10 moves forward, and the moving speed is equal to the roller linear speed V2, at the same time, the winding roll 541 and the unwinding roll 551 work, the second tension control mechanism 531 and the third tension control mechanism 532 reach the preset values ​​F2 and F3, the angle encoder stabilizes at an angle of 0°, and after the angle encoder stabilizes, the linear speeds of the winding roll 541 and the unwinding roll 551 are equal to the rolling speed V2 of the rolling mill 3. At the same time, the first tension control mechanism 321 gradually reaches the preset value F1. After the angle encoder reaches 0°, the extruder 1 automatically starts to extrude the lithium strip 10, and adjusts the speed of the servo hydraulic pump through the tension feedback of the angle encoder, and adjusts the speed of the extruded lithium strip 10 by adjusting the oil intake to maintain the 0° angle position of the angle encoder. During the operation, the second thickness measuring device 511 continuously monitors the thickness T2 of the lithium strip 11 at the outlet of the rolling mill 3. After the measured value T2 stabilizes at ±2μm, the rolling mill 3 switches to the automatic adjustment mode, and adjusts the roll gap T4 in real time through the difference between T2 and the target value T3 so that |T2-T3|≤2μm. After the thickness meets the standard, the rolling speed V2 can be further increased to 30m / min.

[0087] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for producing ultra-thin lithium metal strips, characterized in that: include: An extrusion system, a first tension control mechanism, a rolling mill and a winding roller, a separator unwinding mechanism, and a plurality of guide rollers for supporting lithium strips arranged along the production line are sequentially arranged on the production line; A lithium strip forming die is provided at the discharge port of the extrusion system; The first tension control mechanism comprises a first tension control roller and a first angle encoder arranged in cooperation with the first tension control roller; The first angle encoder is configured to be connected to the extrusion system for communication, and the angle of the first angle encoder is adjusted in real time so that the first tension control roller moves in coordination so that the pressure from the lithium belt applied to the first tension control roller is a first preset value. When the angle of the first angle encoder exceeds a first threshold, the first angle encoder feeds back a signal to the extrusion system, and the extrusion system is configured to adjust the extrusion speed after receiving the first angle encoder signal. Alternatively, the first angle encoder is configured to be connected to the rolling mill in communication, and the angle of the first angle encoder is adjusted in real time so that the first tension control roller moves in coordination so that the pressure from the lithium strip applied to the first tension control roller is a first preset value, and when the angle of the first angle encoder exceeds a first threshold, the first angle encoder feeds back a signal to the rolling mill, and the rolling mill is configured to adjust the rolling speed after receiving the signal from the first angle encoder; During operation, the lithium ribbon extruded by the extrusion system and the forming die is successively wound onto the winding roller via the first tension control mechanism and the rolling mill; the isolation film is continuously unwound by the unwinding mechanism and wound onto the winding roller together with the lithium ribbon.

2. The production system according to claim 1, characterized in that: The production system further includes a second tension control mechanism, the second tension control mechanism being located between the rolling mill and the winding roller; The second tension control mechanism comprises a second tension control roller and a second angle encoder arranged in cooperation with the second tension control roller; The second angular encoder is configured to communicate with the winding roller, and the angle of the second angular encoder is adjusted in real time so that the second tension control roller moves in coordination so that the pressure from the lithium belt applied to the second tension control roller is a second preset value. When the angle of the second angular encoder exceeds a second threshold value, the second angular encoder feeds back a signal to the winding roller, and the winding roller is configured to adjust the winding speed after receiving the second angular encoder signal.

3. The production system according to claim 2, characterized in that: The isolation film unwinding mechanism comprises an unwinding roller and a third tension control mechanism; The third tension control mechanism comprises a third tension control roller and a third angle encoder arranged in cooperation with the third tension control roller; The third angular encoder is configured to be communicated with the unwinding roller, and the angle of the third angular encoder is adjusted in real time so that the third tension control roller moves in coordination so that the pressure exerted on the third tension control roller from the isolation film is a third preset value. When the angle of the third angular encoder exceeds a third threshold value, the third angular encoder feeds back a signal to the unwinding roller, and the unwinding roller is configured to adjust the winding speed after receiving the third angular encoder signal.

4. The production system according to claim 3, characterized in that: The extrusion system includes an extruder, a servo hydraulic pump and a speed sensor, wherein the extruder includes an extrusion barrel for containing lithium material, a push head arranged in the extrusion barrel for extruding the lithium material toward the forming die, a hydraulic push rod connected to the push head, and a hydraulic cylinder connected to the extrusion barrel for moving the push head, the hydraulic cylinder is connected to the servo hydraulic pump for pumping hydraulic oil therein, and the speed sensor is arranged at one end of the hydraulic push rod away from the push head; The production system further includes a control system, a first speed measuring roller, a first thickness measuring device, a second thickness measuring device and a second speed measuring roller; the first speed measuring roller is located between the extrusion system and the first tension control mechanism, the first thickness measuring device is located between the first tension control mechanism and the rolling mill, and the second speed measuring roller and the second thickness measuring device are located between the rolling mill and the winding roller; The control system is in communication with the servo hydraulic pump, the first speed measuring roller, the second speed measuring roller, the first thickness measuring device and the second thickness measuring device, and the control system has a built-in formula: Wherein, Q is the flow rate of the hydraulic cylinder, D is the inner diameter of the extrusion barrel, V0 is the speed of the push head, V1 is the speed of the extruded lithium strip, V2 is the speed of the rolled lithium strip, T1 is the thickness of the extruded lithium strip measured by the first thickness measuring device, T2 is the thickness of the rolled lithium strip measured by the second thickness measuring device, and W is the width of the lithium strip; Set any value among Q, V0, V1 and V2, and the other three values ​​can be calculated by the formula, and the calculated values ​​are compared with the values ​​of actual detection feedback. The control system adjusts the hydraulic cylinder liquid inlet flow or the rolling lithium strip speed according to the comparison result so that the calculated result is consistent with the actual measured result; Optionally, the inner diameter of the extrusion barrel is 150-700 mm, the wall thickness is 20-100 mm, and the length is 300-1000 mm.

5. The production system according to claim 4, characterized in that: The production system further comprises a deviation correction control mechanism, which is arranged between the first tension control mechanism and the second thickness measuring device, and comprises a deviation correction sensor arranged in front and a deviation correction guide roller group arranged in the back.

6. The production system according to claim 5, characterized in that: The production system further comprises a bonding roller, wherein the bonding roller is located between the second tension control mechanism and the winding roller; During operation, the lithium ribbon extruded by the extrusion system and the forming die is successively wound onto the winding roller through the first speed measuring roller, the first tension control mechanism, the deviation correction control mechanism, the first thickness measuring device, the rolling mill, the second thickness measuring device, the second speed measuring roller, the second tension control mechanism and the combining roller; the isolation film wound on the unwinding roller is continuously unwound and wound onto the winding roller together with the lithium ribbon through the third tension control mechanism and the combining roller.

7. The production system according to claim 3, characterized in that: The winding roller and / or the unwinding roller is an inflatable shaft with a length of 300 to 800 mm.

8. The production system according to claim 1, characterized in that: The rolling mill comprises a pair of symmetrically arranged back-up rolls and a pair of working rolls, wherein the pair of working rolls are located between the pair of back-up rolls, and the gap between the working rolls is a rolling gap; Optionally, the diameter of each of the backing rollers is 100 to 500 mm; Optionally, the diameter of each working roll is 50 to 300 mm; Optionally, the length of the backing roller and / or the working roller is 200 to 700 mm; Optionally, the backing roller and the working roller have a surface finish of Ra≤0.5 μm and a hardness of RHC≥50 degrees.

9. The production system according to claim 1, characterized in that: The guide roller has a diameter of 50 to 150 mm, a length of 200 to 700 mm, a surface finish of Ra ≤ 0.2 μm, and a hardness of RHC ≥ 50 degrees.

10. A method for producing an ultra-thin lithium metal strip, characterized in that: The method is implemented by using a production system as described in any one of claims 1 to 9.

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