Manufacturing method of negative electrode of lithium battery

Abstract

The invention provides a manufacturing method of a lithium battery negative electrode. The electroplating equipment is provided, the electroplating equipment is provided with a drying chamber, and an electroplating bath, an electroplating wheel set and a film pasting wheel set are arranged in the drying chamber. And the copper foil is arranged in the drying chamber. The electroplating wheel set conveys the copper foil to enable the lithium metal layer to be formed on the copper foil, and the copper foil and the lithium metal layer form a copper-lithium composite metal layer. The film pasting wheel set conveys the copper-lithium composite metal layer and attaches the protective film to the copper-lithium composite metal layer.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a negative electrode of a lithium battery. Background Art

[0002] Lithium metal is a key material for the negative electrode of lithium batteries. However, due to its high activity, lithium metal is easily oxidized and loses its activity by reacting with water, oxygen, etc. This will affect the performance of lithium batteries. Therefore, how to improve the negative electrode of lithium batteries is a key factor in the future development of lithium batteries. Summary of the invention

[0003] The present invention provides a method for manufacturing a negative electrode of a lithium battery. The composite negative electrode structure manufactured by the method can effectively improve the performance of the lithium battery and is conducive to mass production.

[0004] A method for manufacturing a negative electrode of a lithium battery of the present invention comprises at least the following steps. An electroplating device is provided, wherein the electroplating device has a drying chamber, and the drying chamber includes an electroplating tank, an electroplating wheel group and a film-attaching wheel group. A copper foil is arranged in the drying chamber. The electroplating wheel group conveys the copper foil so that a lithium metal layer is formed on the copper foil, and the copper foil and the lithium metal layer constitute a copper-lithium composite metal layer. The film-attaching wheel group conveys the copper-lithium composite metal layer and attaches a protective film to the copper-lithium composite metal layer.

[0005] In one embodiment of the present invention, the electroplating tank includes a first electrode, and the electroplating wheel set includes a first guide wheel and a second guide wheel disposed in the electroplating tank, and a first conductive wheel and a second conductive wheel disposed outside the electroplating tank. The first guide wheel and the second guide wheel are configured to make the copper foil in the electroplating tank parallel to the first electrode. The first conductive wheel and the second conductive wheel serve as the second electrode.

[0006] In one embodiment of the present invention, the drying chamber further comprises a copper foil supply device and a protective film supply device, wherein the copper foil supply device is connected to the electroplating wheel set, and the protective film supply device is connected to the laminating wheel set.

[0007] In one embodiment of the present invention, the material of the protective film includes a polyimide film, a polyester film or a water- and gas-blocking film.

[0008] In one embodiment of the present invention, the drying chamber further comprises a drying device, and the drying device is configured to remove the organic solvent on the copper-lithium composite metal layer.

[0009] In one embodiment of the present invention, the drying device comprises an air knife, a roller, an infrared heater or a combination thereof.

[0010] In one embodiment of the present invention, the environment of the drying chamber is composed of an inert gas.

[0011] In one embodiment of the present invention, the protective film at least completely covers the surface of the lithium metal layer.

[0012] In one embodiment of the present invention, the protective film directly contacts the lithium metal layer and the copper foil.

[0013] In one embodiment of the present invention, the plating solution in the above-mentioned plating tank includes a lithium salt and an organic solvent, and the lithium salt includes lithium hexafluorophosphate, lithium hexafluoroborate, lithium bis(trifluoromethylsulfonyl)amide or a combination thereof, and the organic solvent includes ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylene glycol dimethyl ether, dimethyl ether or a combination thereof.

[0014] Based on the above, the negative electrode of the lithium battery of the present invention is manufactured in a drying room, and the lithium metal can be continuously deposited on the copper foil in the electroplating tank to form a copper-lithium composite metal layer by means of the electroplating wheel group in the drying room, and the protective film can be continuously attached to the copper-lithium composite metal layer pulled out of the electroplating tank by means of the film sticking wheel group in the drying room. In this way, the copper foil and protective film with low reactivity can effectively reduce the probability of lithium metal being oxidized, so the composite negative electrode structure manufactured by it can effectively improve the performance of the lithium battery and facilitate mass production.

[0015] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flowchart of a method for manufacturing a negative electrode of a lithium battery according to an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of an electroplating device according to an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of a cross-section of a negative electrode of a lithium battery according to an embodiment of the present invention.

[0019] Figure 4 FIG. 4 is a cross-sectional schematic diagram of a negative electrode of a lithium battery according to another embodiment of the present invention. DETAILED DESCRIPTION

[0020] In the following detailed description, for the purpose of illustration and not limitation, exemplary embodiments that disclose specific details are described to provide a thorough understanding of the various principles of the present invention. However, it will be apparent to one of ordinary skill in the art that, with the benefit of this disclosure, the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. In addition, descriptions of well-known devices, methods, materials, and other specific details may be omitted to avoid obscuring the description of the various principles of the present invention.

[0021] In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values ​​in the range one by one in the specification. Therefore, the description of a specific numerical range covers any value in the numerical range and a smaller numerical range defined by any value in the numerical range, just as the arbitrary value and the smaller numerical range are written in the description text of the specification.

[0022] Unless otherwise specified, the term "between" used in this specification to define a numerical range is intended to cover a range equal to the endpoint value and between the endpoint values. For example, a size range is between a first value and a second value, which means that the size range can cover the first value, the second value and any value between the first value and the second value.

[0023] In this document, non-limiting terms (such as may, could, for example, or other similar terms) mean optional or optional implementation, inclusion, addition, or presence.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood or generally understood in the technical field to which the present invention belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the relevant technical context and should not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0025] Figure 1 : is a flow chart of a method for manufacturing a negative electrode of a lithium battery according to an embodiment of the present invention. The method for manufacturing a negative electrode of a lithium battery according to the present invention may include at least the following steps. Figure 1 First, an electroplating device is provided, wherein the electroplating device has a drying chamber, and the drying chamber includes an electroplating tank, an electroplating wheel set, and a film-attaching wheel set (step S100). Next, a copper foil is placed in the drying chamber (step S200), and the electroplating wheel set conveys the copper foil so that a lithium metal layer is formed on the copper foil, and the copper foil and the lithium metal layer constitute a copper-lithium composite metal layer (step S300). Then, the film-attaching wheel set conveys the copper-lithium composite metal layer and attaches a protective film to the copper-lithium composite metal layer (step S400). Accordingly, the negative electrode of the lithium battery of the present invention is manufactured in a drying room, and the lithium metal can be continuously deposited on the copper foil in the electroplating tank to form a copper-lithium composite metal layer by means of the electroplating wheel group in the drying room, and the protective film can be continuously attached to the copper-lithium composite metal layer pulled out of the electroplating tank by means of the film sticking wheel group in the drying room. In this way, the copper foil and protective film with low reactivity can effectively reduce the probability of lithium metal being oxidized, so the composite negative electrode structure manufactured by it can effectively improve the performance of the lithium battery and facilitate mass production.

[0026] Figure 2Schematic diagram of an electroplating device according to an embodiment of the present invention. Figure 3 Schematic diagram of a cross-section of a negative electrode of a lithium battery according to an embodiment of the present invention. Figure 4 FIG. 4 is a cross-sectional schematic diagram of a negative electrode of a lithium battery according to another embodiment of the present invention.

[0027] In one embodiment, the manufacturing method of the negative electrode of a lithium battery can be Figure 2 The present invention is manufactured by the electroplating equipment 100, but the present invention is not limited to this. Without departing from the spirit and scope of the present invention, the electroplating equipment may have other suitable devices and configurations not described herein.

[0028] Please refer to Figures 2 to 4 The electroplating equipment 100 has a drying chamber 110, and the drying chamber 110 includes an electroplating tank 111, an electroplating wheel set 112, and a film-attaching wheel set 113. In one embodiment, the dew point temperature of the drying chamber is, for example, less than -40°C, and the environment E of the drying chamber 110 is composed of an inert gas to reduce the probability of lithium metal reacting with water or oxygen in the environment during the electroplating process, and further improve the production quality of the negative electrode of the lithium battery, but the present invention is not limited thereto. Here, the inert gas is, for example, nitrogen, argon or other suitable inert gases and combinations thereof.

[0029] Further, the electroplating tank 111 includes a first electrode 111a, and the electroplating wheel set 112 includes a first guide wheel 112a and a second guide wheel 112b disposed in the electroplating tank 111, and a first conductive wheel 112c and a second conductive wheel 112d disposed outside the electroplating tank 111. The present invention does not limit the specific aspects of the first guide wheel 112a, the second guide wheel 112b, the first conductive wheel 112c, and the second conductive wheel 112d, as long as the first guide wheel 112a and the second guide wheel 112b can be configured to make the electroplating tank The copper foil 10 in 111 is parallel to the first electrode 111a. The first conductive wheel 112c and the second conductive wheel 112d can be used as the second electrode (the counter electrode of the first electrode 111a) and both belong to the protection scope of the present invention. The material of the first guide wheel 112a and the second guide wheel 112b can be any suitable material that does not react with the plating solution. The material of the first electrode 111a includes lithium metal, stainless steel or the like, and the material of the first conductive wheel 112c and the second conductive wheel 112d includes titanium and stainless steel.

[0030] In this embodiment, the drying chamber 110 further includes a copper foil supply device 114 connected to the electroplating wheel set 112, wherein the copper foil 10 is, for example, a copper foil roll, and the copper foil device 114 can be in the form of a roller to continuously send the copper foil roll to the electroplating wheel set 112 for electroplating. Figure 2As shown, the copper foil 10, for example, first passes through the first conductive wheel 112c and is then pulled into the electroplating tank 111 by the first guide wheel 112a and the second guide wheel 112b. The first guide wheel 112a and the second guide wheel 112b adjust the direction of the copper foil 10 so that it is parallel to the first electrode 111a ( Figure 2 Schematically shown as parallel in the horizontal direction, however, in an embodiment not shown, it can also be parallel in the vertical direction), and the copper foil 10 is electroplated to make lithium metal (such as Figure 3 , Figure 4 After the lithium metal layer 20 in the copper foil 10 is deposited on the copper foil 10 to form a copper-lithium composite metal layer, it leaves the electroplating tank 111 and is pulled to the second conductive wheel 112d. Here, the thickness of the copper foil 10 can be between 6 microns and 35 microns, and the deposition thickness of the lithium metal is between 0.5 microns and 20 microns, but the present invention is not limited thereto.

[0031] It should be noted that the plating solution in the plating tank 111 includes a lithium salt and an organic solvent, and the lithium salt includes lithium hexafluorophosphate, lithium hexafluoroborate, lithium bis(trifluoromethylsulfonyl)amide or a combination thereof, and the organic solvent includes ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylene glycol dimethyl ether, dimethyl ether or a combination thereof, and the specific details of the electroplating process can be understood by anyone with ordinary knowledge in the relevant technical field and will not be repeated here.

[0032] In addition, the film laminating wheel set 113 includes a third guide wheel 113a connected to the second conductive wheel 112d and a pressing laminating wheel 113b connected to the third guide wheel 113a, and the drying chamber 110 further includes a protective film device 115 connected to the laminating wheel set 113, wherein the protective film (such as Figure 3 , Figure 4 The protective film 30 in the embodiment is, for example, a polyimide (PI) film, a polyester (PET) film or a water-blocking and gas-blocking film, and the protective film device 115 can be in the form of a roller to continuously send the aforementioned roll to the pressing and laminating wheel 113b for the laminating process. Figure 3 , Figure 4 The protective film 30) can have any suitable thickness, and the present invention is not limited thereto.

[0033] In one embodiment, the water- and gas-blocking film is, for example, an aluminum composite film roll (aluminum composite film) that is a non-stretched polypropylene film (CPP film) that is vapor-deposited with aluminum, or an aluminum foil (thickness, for example, between 6 microns and 35 microns) that is attached with a CPP film, so as to more effectively protect the lithium metal from being stably oxidized by water or air in the environment by virtue of the water- and oxygen-blocking properties of aluminum. However, the present invention is not limited thereto, and may also be other water- and gas-blocking films, such as the product name of Mitsui Chemicals TAKELAC TM WPB-341 water- and gas-barrier film. Here, the water- and gas-barrier film preferably has a water vapor permeability of 0.5 g / m2 / day and oxygen permeability 0.5cc / m 2 / day or less.

[0034] In one embodiment, if Figure 3 As shown, the lithium metal layer 20 can completely cover the surface of the copper foil 10, so the protective film 30 subsequently covered on the lithium metal layer 20 may not directly contact the copper foil 10, but the present invention is not limited thereto. In another embodiment, as shown in FIG. Figure 4 As shown, the lithium metal layer 20 can partially cover the surface of the copper foil 10, exposing part of the surface of the copper foil 10, so that the protective film 30 subsequently covered on the lithium metal layer 20 can directly contact the lithium metal layer 20 and the copper foil 10, that is, the protective film 30 at least completely covers the surface of the lithium metal layer 20, and optionally covers the surface of the copper foil 10.

[0035] In some embodiments, the drying chamber 110 further includes a drying device 116, and the drying device 116 is configured to remove the organic solvent on the copper-lithium composite metal layer, wherein the drying device 116 includes an air knife, a roller, an infrared (IR) heater or a combination thereof, for example, Figure 2 As shown, the drying device 116 includes a first drying device 116a and a second drying device 116b, the first drying device 116a can be arranged between the second guide wheel 112b and the second conductive wheel 112d, and the second drying device can be arranged between the second conductive wheel 112d and the third guide wheel 113a, wherein the drying device 116 can be arranged on both sides of the copper-lithium composite metal layer at the same time to simultaneously dry the organic solvent on both sides, but the present invention is not limited to this.

[0036] In one embodiment, the drying chamber 110 further includes a winding device 117 connected to the bonding wheel group 113 to roll up the composite negative electrode structure including the copper foil 10, the lithium metal layer 20 and the protective film 30. In this way, the subsequent lithium battery process speed can be improved to meet the needs of mass production.

[0037] The following embodiments are listed to illustrate the effects of the present invention, but the scope of rights of the present invention is not limited to the scope of the embodiments.

[0038] <Example>

[0039] First, prepare the 6um~8um copper foil and protective film (TAKELAC TM WPB-341 water- and gas-blocking film), electroplating solution: solvent: ethylene glycol dimethyl ether (DOL): dimethyl ether (DME) = 1:1, 1M lithium salt (LiTFSI) and lithium nitrate LiNO3 are 1-5%, and the lead wire is installed in the electroplating equipment (100), in which the drying chamber always maintains a water vapor dew point less than -40°C.

[0040] Step 2: The nitrogen flow rate into the electroplating tank (111) is 50cc / minute (min).

[0041] Step 3: The electroplating production line is operated at a production rate of 0.1-30 M / min using the above-mentioned lithium battery negative electrode manufacturing method until the length of each roll is about 3000-10000 meters (m), and then the production is stopped.

[0042] Step 4: Collect the materials and take out the finished product, and return to step 1 to continue production to achieve the purpose of mass production.

[0043] In summary, the negative electrode of the lithium battery of the present invention is manufactured in a drying room, and the lithium metal can be continuously deposited on the copper foil in the electroplating tank to form a copper-lithium composite metal layer by means of the electroplating wheel group in the drying room, and the protective film can be continuously attached to the copper-lithium composite metal layer pulled out of the electroplating tank by means of the film-sticking wheel group in the drying room. In this way, the copper foil and protective film with low reactivity can effectively reduce the probability of lithium metal being oxidized, so the composite negative electrode structure manufactured by it can effectively improve the performance of the lithium battery and facilitate mass production.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a negative electrode of a lithium battery, characterized in that: include: Provide an electroplating device, wherein the electroplating device has a drying chamber, and the drying chamber includes an electroplating tank, an electroplating wheel set, and a film pasting wheel set; Placing the copper foil in the drying chamber; The electroplating wheel group conveys the copper foil so that a lithium metal layer is formed on the copper foil, and the copper foil and the lithium metal layer constitute a copper-lithium composite metal layer; as well as The film sticking wheel group transports the copper-lithium composite metal layer and sticks a protective film on the copper-lithium composite metal layer.

2. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The electroplating tank includes a first electrode, and the electroplating wheel assembly includes: A first guide wheel and a second guide wheel are disposed in the electroplating tank, wherein the first guide wheel and the second guide wheel are configured to make the copper foil in the electroplating tank parallel to the first electrode; and The first conductive wheel and the second conductive wheel are arranged outside the electroplating tank, wherein the first conductive wheel and the second conductive wheel serve as second electrodes.

3. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The drying chamber further includes a copper foil supply device and a protective film supply device, wherein the copper foil supply device is connected to the electroplating wheel set, and the protective film supply device is connected to the laminating wheel set.

4. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The material of the protective film includes a polyimide film, a polyester film or a water-blocking and gas-blocking film.

5. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The drying chamber further includes a drying device, and the drying device is configured to remove the organic solvent on the copper-lithium composite metal layer.

6. The method for manufacturing a negative electrode of a lithium battery according to claim 5, characterized in that: The drying device includes an air knife, a roller, an infrared heater or a combination thereof.

7. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The environment of the drying chamber is composed of an inert gas.

8. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The protective film at least completely covers the surface of the lithium metal layer.

9. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The protection film directly contacts the lithium metal layer and the copper foil.

10. The method for manufacturing a negative electrode of a lithium battery according to claim 1, characterized in that: The plating solution in the plating tank includes a lithium salt and an organic solvent, and the lithium salt includes lithium hexafluorophosphate, lithium hexafluoroborate, lithium bis(trifluoromethylsulfonyl)amide or a combination thereof, and the organic solvent includes ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylene glycol dimethyl ether, dimethyl ether or a combination thereof.

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