Device for preparing ultra-thin and ultra-wide metal lithium composite material

Abstract

The utility model discloses a device for preparing an ultra-thin and ultra-wide metal lithium composite material. The device comprises an extrusion die head which is a slit type extrusion die head, and a heating element is arranged in the extrusion die head; the back roller has a cooling function, so that the lithium liquid coated by the extrusion die head is quickly cured; the lithium melting tank is used for dissolving metal lithium, heating metal lithium liquid to a specified temperature and supplying high-temperature lithium liquid to the extrusion die head; the high-pressure gas tank is connected with the lithium melting tank and is used for providing high-pressure gas to convey the lithium liquid in the lithium melting tank to the extrusion die head; a lithium-plated base material is uncoiled by the unwinding assembly and then bypasses the back roller to finish coating, and a lithium composite strip formed after coating is wound by the winding assembly. According to the device for preparing the ultra-thin and ultra-wide metal lithium composite material, the high-temperature lithium liquid is uniformly coated on the lithium plating base material in a coating manner, so that the ultra-thin and ultra-wide metal lithium composite material can be prepared.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of battery manufacturing, especially to the technical field of lithium battery, specifically relates to a device for preparing ultrathin ultrawide metal lithium composite material. BACKGROUND

[0002] The existing ultrathin lithium strip preparation technology mainly relies on rolling, extrusion and coating process, which has problems such as high equipment requirement, poor thickness uniformity and limited width.

[0003] Chinese patent application CN 112410785A discloses a preparation device and method for large-width ultrathin metal lithium strip, which uses lithium liquid transfer roller, hot scraper and other devices to coat lithium liquid by adjusting the gap and roller gap, and obtains a lithium strip with a thickness of 5-50 μm. However, in practice, due to the extremely high surface tension of metal lithium liquid, it is difficult for the lithium liquid to adhere uniformly to the lithium liquid transfer roller, and even if a small amount of lithium liquid is coated on the substrate, it will also shrink into a spherical shape due to surface tension. The produced strip material often has defects such as missing coating, large-area holes and several point-like agglomerated protrusions. Patent No. CN 107425175 B uses a slit die to flow onto a conductive substrate, and then a double-roller calender is used to calender according to the thickness requirement. Patent application CN 119069649 A discloses a negative electrode strip-shaped interval pre-lithiation device and method with coating function, which also coats lithium liquid onto the substrate to obtain an ultrathin lithium film. Due to the surface tension of metal lithium liquid, the above-mentioned methods all result in defects such as uneven thickness, missing coating and holes in the produced ultrathin lithium film, and the product quality is not stable. Patent No. CN 109346680 B proposes to add a conductive agent to the lithium liquid to adjust the viscosity of the liquid lithium, which slightly improves the coating effect, but still has problems such as poor lithium affinity between the liquid lithium and the substrate, agglomeration of the liquid lithium on the substrate after coating, and the introduction of a conductive agent with low energy density.

[0004] In addition, patent applications CN 113732058 A, CN 115101717 A, CN 114597331 A and CN 112151758 A all mention the use of roller pressing or multi-stage calendering method to produce ultrathin lithium film. Although this method can produce ultrathin lithium film with acceptable quality, the width is limited, and the production width is often limited to within 200 mm.

[0005] Therefore, there is still a need for an industrially feasible process that can produce ultrathin (thickness 10-30 microns) lithium film with ultra-wide width (width 200-800 mm). SUMMARY

[0006] The present inventors have found through extensive experimental research that increasing the temperature of the metallic lithium liquid can significantly reduce its surface tension, thereby optimizing the performance during the coating process. It is particularly important that when the heated metallic lithium liquid is coated on the surface of the lithium-containing layer of the strip, the agglomeration problem caused by high tension of the lithium liquid is not encountered, on the contrary, the lithium liquid can quickly and uniformly spread out. Based on these breakthrough findings, the present application proposes an innovative device for preparing ultra-thin and ultra-wide metallic lithium composite material. The device can ensure that the liquid metallic lithium is uniformly coated on the substrate to form an ultra-wide micron-level ultra-thin lithium film.

[0007] It is particularly worth mentioning that the process flow of the device of the present application is simple, and batch, continuous and roll-to-roll efficient production methods can be realized, which is undoubtedly a groundbreaking achievement for the lithium ion battery industry. It not only greatly improves the production efficiency, but also is expected to further optimize the performance and cost of lithium ion batteries, opening up a new way for the development of new energy fields.

[0008] The purpose of the present application is to provide a device for preparing an ultra-thin and ultra-wide metallic lithium composite material, which can produce an ultra-wide and ultra-thin metallic lithium composite material with a thickness of 10-30 microns and a width of 200-800 mm.

[0009] The purpose of the present application can be achieved by the following technical solutions.

[0010] A device for preparing an ultra-thin and ultra-wide metallic lithium composite material, the device comprising: an extrusion die, the extrusion die being a slit-type extrusion die, and a heating element being provided inside the extrusion die; a lithium melting tank for heating metallic lithium to a specified temperature to form a high-temperature lithium liquid; a high-pressure gas tank connected to the lithium melting tank, providing high-pressure gas to transport the lithium liquid in the lithium melting tank to the extrusion die; a back roller oppositely arranged and cooperatively used with the extrusion die, the back roller having a cooling device for controlling the surface temperature of the back roller; an unwinding assembly and a winding assembly, the unwinding assembly and the winding assembly being cooperatively used with the back roller, wherein the lithium-coated substrate is unwound by the unwinding assembly, then passes through the back roller to complete the coating, and the lithium composite strip formed after coating is wound by the winding assembly.

[0011] Optionally, the slit length of the slit-type extrusion die is 200-800 mm.

[0012] Optionally, the back roller further comprises a back roller driving device.

[0013] Optionally, the lithium melting tank has a heating and heat preservation device.

[0014] Optionally, the high-pressure gas tank contains inert gas, preferably argon.

[0015] Optionally, a pressure reducing valve and a flow control valve are arranged on the gas pipeline connecting the high-pressure gas tank and the molten lithium tank.

[0016] Optionally, the unwinding assembly comprises at least an unwinding shaft and a magnetic powder brake, and the winding assembly comprises a winding shaft and a motor.

[0017] Optionally, the unwinding / winding assembly comprises at least one of a tension detection element, a deviation rectifying sensor, and a deviation rectifying execution mechanism.

[0018] Optionally, a switch valve for cutting off / communicating lithium liquid is further arranged between the molten lithium tank and the extrusion die.

[0019] Optionally, the molten lithium tank can also form a closed sealed tank body by closing the valves between the high-pressure gas tank and the extrusion die.

[0020] Optionally, the molten lithium tank is further provided with a vacuum pump system, so that the molten lithium tank can maintain a vacuum environment.

[0021] Optionally, the device for preparing ultra-thin and ultra-wide metal lithium composite material can be further provided with an evaporation device for evaporating metal lithium on a substrate to form a lithium-plated substrate.

[0022] The technical scheme of the utility model has at least one of the following advantages:

[0023] 1. The liquid metal lithium in the extrusion die is kept in a high-temperature state, which reduces the tension of the metal lithium and improves the coating performance.

[0024] 2. The metal lithium liquid at high temperature can quickly and uniformly spread on the surface of the lithium-containing strip during coating, forming a uniform coating.

[0025] 3. The temperature of the back roller is accurately controlled, and the low-temperature back roller helps the lithium liquid to quickly cool and solidify.

[0026] 4. The technical scheme of the utility model is simple and easy to implement, and a roll-to-roll scheme is adopted, which can produce in batches and quickly. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of one specific embodiment of the device for preparing ultra-thin and ultra-wide metal lithium composite material of the utility model.

[0028] FIG. 1 is a schematic diagram of the device for preparing ultra-thin and ultra-wide metal lithium composite material of the utility model.

[0029] 1 molten lithium tank; 2 high-pressure gas tank; 3 pressure regulating valve; 4 flow control valve; 5 gas pipeline; 6 switch valve; 7 conveying pipe; 8 extrusion die; 9 heating element; 10 back roller; 11 unwinding assembly; 12 idler; 13 winding assembly; 14 lithium-plated substrate; 15 lithium composite strip. DETAILED DESCRIPTION

[0030] The specific embodiments of the utility model are described below. It should be understood that other various embodiments can be conceived and modified by those skilled in the art according to the teachings of the present disclosure without departing from the scope or spirit of the utility model. Therefore, the following specific embodiments are not limiting in nature.

[0031] As Figure 1 The device for preparing ultra-thin and ultra-wide metal lithium composite material is shown in the schematic diagram of one specific embodiment of the utility model. In this embodiment, the device for preparing ultra-thin and ultra-wide metal lithium composite material mainly comprises a lithium melting tank 1, a high-pressure gas tank 2, an extrusion die head 8, a back roller 10, a pay-off assembly 11 and a winding assembly 13. The high-pressure gas tank 2 is connected to the top position of the lithium melting tank 1 through a gas pipe 5, and a pressure regulating valve 3 and a flow control valve 4 are arranged on the gas pipe 5; the flow control valve 4 has a cutoff function, i.e. completely isolates the high-pressure gas source from the lithium melting tank 1. One end of the bottom of the lithium melting tank 1 is connected to the extrusion die head 8 through a conveying pipe 7, and a switch valve 6 is arranged at the end of the conveying pipe 7 close to the lithium melting tank 1; when the switch valve 6 is in the cutoff state, the lithium liquid in the lithium melting tank 1 cannot be output through the conveying pipe 7. The extrusion die head 8 is also provided with a heating element 9, and optionally, a temperature detection element is also arranged on the extrusion die head, and the heating element 9 can heat the extrusion die head, and the feedback of the temperature detection element can achieve the purpose of accurately controlling the temperature of the extrusion die head 8. The pay-off assembly 11 unwinds the lithium-plated base material 14, passes through the back roller 10 and then completes the winding by the winding assembly 13, and a supporting roller 12 is arranged between the pay-off assembly 11 and the back roller 10 and between the back roller 10 and the winding assembly 13. The back roller 10 has a cooling function and can quickly cool and solidify the coated lithium composite strip 15.

[0032] The specific operation process of the device of the utility model is as follows:

[0033] Preparation work before coating:

[0034] Firstly, metal lithium (which can be lithium ingot, lithium strip, lithium liquid, etc.) is added into the lithium melting tank 1, the lithium melting tank 1 is closed, the flow control valve 4 and the switch valve 6 are in the cutoff state, and the whole lithium melting tank 1 is in a closed state; a vacuum pump system (not shown in the figure) connected to the lithium melting tank 1 is started to perform vacuumizing operation on the lithium melting tank 1, so that the lithium melting tank 1 is in a vacuum state; the lithium melting tank 1 is heated, so that the metal lithium in the lithium melting tank 1 is completely dissolved into lithium liquid, and the lithium liquid temperature reaches the set value. Then, the lithium-plated base material 14 is installed to the pay-off assembly 11 for unwinding, and the lithium-plated base material 14 is fixed to the winding assembly 13 after passing through the supporting roller 12, the back roller 10 and the supporting roller 12 in sequence. Subsequently, the heating element 9 on the extrusion die head 8 is started to preheat the extrusion die head 8 until the set temperature is reached. Finally, the cooling function of the back roller 10 is started to precool the back roller 10.

[0035] Coating work starts:

[0036] First, close the vacuum system on the lithium tank 1, open the flow control valve 4, open the switch valve 6, and start the winding assembly 13 and the unwinding assembly 11. Then, the high-temperature lithium liquid is delivered to the extrusion die 8 through the delivery pipe 7 by controlling the gas pressure and flow delivered to the lithium tank 1; the delivery flow of the high-temperature lithium liquid is determined by the winding speed and the set thickness. According to the set thickness and the actual thickness of the coated strip, the distance between the extrusion die 8 and the back roll 10 is adjusted until the lithium composite strip of the set thickness is stably produced. In this link, the lithium-plated base material 14 is coated with lithium liquid through the extrusion die 8 and forms the lithium composite strip 15 after being cooled by the back roll 10; the lithium composite strip 15 is wound by the winding assembly 13.

[0037] Coating work ends:

[0038] First, the flow control valve 4 and the switch valve 6 are in the closed state, and the delivery of the high-temperature lithium liquid is stopped. Then, the heating function of the lithium tank 1, the heating function of the heating element 9 and the cooling function of the back roll 10 are turned off. Finally, the winding and unwinding functions of the unwinding assembly 11 and the winding assembly 13 are turned off, and the produced lithium composite strip 15 is taken down and transferred to the next process link. The coating work ends.

[0039] The key to the device of the utility model to stably complete the coating lies in:

[0040] 1. The extrusion die 8 is heated to further improve or maintain the temperature of the lithium liquid, so that the coated lithium liquid maintains a high-temperature state, effectively reduces the surface tension of the lithium liquid, and the coated lithium liquid can quickly fuse with the lithium layer on the lithium-plated base material 14, so that the coating is more stable and uniform.

[0041] 2. The lithium liquid is delivered by air pressure, and the delivery flow of the lithium liquid is precisely controlled, so that the coating thickness is uniform and stable.

[0042] 3. The low-temperature back roll helps the lithium liquid to quickly cool and solidify.

[0043] Although the utility model has been disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model, therefore the protection scope of the utility model should be limited by the range defined by the claims.

Claims

1. An apparatus for preparing an ultrathin and ultra-wide metal lithium composite material, characterized in that, The device comprises: an extrusion die, which is a slit extrusion die, and is internally provided with a heating element; a molten lithium tank for heating metal lithium to a specified temperature to form a high-temperature lithium liquid; a high-pressure gas tank connected to the molten lithium tank, providing high-pressure gas to transport the lithium liquid in the molten lithium tank to the extrusion die; a back roller arranged opposite to the extrusion die and used in cooperation, the back roller being provided with a cooling device for controlling the surface temperature of the back roller; an unwinding assembly and a winding assembly used in cooperation with the back roller, wherein the lithium-plated substrate is unwound from the unwinding assembly, passes around the back roller to complete coating, and the lithium composite tape formed after coating is wound by the winding assembly.

2. The apparatus of claim 1, wherein, The slit length of the slit extrusion die is 200-800 mm.

3. The apparatus of claim 1, wherein, The back roller further comprises a back roller driving device.

4. The apparatus of claim 1, wherein, The molten lithium tank is provided with a heating and temperature maintaining device.

5. The apparatus of claim 1, wherein, The high-pressure gas tank contains inert gas.

6. The apparatus of claim 1, wherein, A pressure reducing valve and a flow control valve are arranged on the gas pipeline connecting the high-pressure gas tank and the molten lithium tank.

7. The apparatus of claim 1, wherein, The unwinding assembly at least comprises an unwinding shaft and a magnetic powder brake, and the winding assembly comprises a winding shaft and a motor.

8. The apparatus of claim 1, wherein, The unwinding / winding assembly comprises at least one of a tension detection element, a deviation correction sensor, and a deviation correction execution mechanism.

9. The apparatus of claim 1, wherein, A switch valve for cutting off / communicating the lithium liquid is further arranged between the molten lithium tank and the extrusion die.

10. The apparatus of claim 1, wherein, The molten lithium tank can also form a closed sealed tank body by closing the valves between the high-pressure gas tank and the extrusion die, and a vacuum pump is used to maintain a vacuum environment in the molten lithium tank.

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