WO2020031697A1 - Thermal spray system, thermal spray method and method for producing lithium secondary battery - Google Patents

Abstract

This thermal spray system is provided with a thermal spray unit, a surface treatment unit and a wind-up unit. The thermal spray unit is configured so as to form a coating film on a first surface of a base material by means of thermal spray of a powder material. The surface treatment unit is configured so as to stabilize the surface of the coating film. The wind-up unit is configured so as to wind up the base material after the stabilization of the surface of the coating film.

Description

Thermal spray system, thermal spray method, and method of manufacturing lithium secondary battery

The following disclosure relates to a thermal spraying system, a thermal spraying method, and a method for manufacturing a lithium secondary battery.

As a method of mass-producing electrochemical cells, an apparatus for film formation of an electrochemical cell including a process chamber configured to form a material on a substrate wound between two reels has been proposed ( Patent Document 1).

Also, an electrode manufacturing apparatus has been proposed in which an electrode material on an electrode sheet is doped with lithium ions to manufacture an electrode for a lithium ion capacitor (Patent Document 2). In this apparatus, a lithium-containing powder is melted and sprayed onto an electrode material of an electrode sheet carried into a processing chamber to form a lithium thin film in an inert gas atmosphere. In this technology, spontaneous ignition of lithium or the like is prevented by using an inert gas that does not react with lithium.

JP 2014-224322 A Japanese Patent No. 6084841

The present disclosure provides a technique capable of winding a substrate on which a coating is formed without deteriorating the quality of the coating formed by thermal spraying.

に お い て In the disclosed embodiment, the thermal spraying system includes a thermal spraying unit, a surface treatment unit, and a winding unit. The thermal spray portion is configured to form a coating on the first surface of the substrate by thermal spraying the powder material. The surface treatment is configured to stabilize the surface of the coating. The winding unit is configured to wind the substrate after stabilization of the surface of the coating.

According to the disclosed embodiment, there is an effect that the substrate on which the coating is formed can be wound without deteriorating the quality of the coating formed by thermal spraying.

FIG. 1 is a schematic sectional view illustrating an example of the configuration of the thermal spraying system according to the first embodiment. FIG. 2 is a schematic perspective view showing an example of the configuration of the thermal spraying system according to the first embodiment. FIG. 3 is a flowchart illustrating an example of the flow of the thermal spraying process in the thermal spraying system according to the first embodiment. FIG. 4A is a diagram for describing an example of a coating formed by a thermal spray processing unit of the thermal spray system according to the first embodiment. FIG. 4B is a diagram illustrating an example of a stabilization layer formed by the surface treatment unit of the thermal spraying system according to the first embodiment. FIG. 5 is a table showing experimental results regarding surface treatment conditions according to the first embodiment. FIG. 6A is a diagram illustrating a configuration example 1 of the thermal spraying system according to the second embodiment. FIG. 6B is a diagram illustrating a configuration example 2 of the thermal spraying system according to the second embodiment. FIG. 6C is a diagram illustrating a configuration example 3 of the thermal spraying system according to the second embodiment. FIG. 7 is a diagram for explaining a cooling mechanism included in the thermal spraying system according to the third embodiment.

Hereinafter, embodiments of a thermal spraying system, a thermal spraying method, and a method of manufacturing a lithium secondary battery disclosed in the present application will be described in detail with reference to the accompanying drawings. The present disclosure is not limited by the embodiments described below. In addition, it is necessary to keep in mind that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, and the like may be different from reality. Further, the drawings may include portions having different dimensional relationships and ratios. In addition, the embodiments can be appropriately combined within a range that does not contradict processing contents.

<Preritiation>
Before describing the first embodiment, first, prerelation will be described.

(4) In a lithium secondary battery, lithium ions move from the positive electrode to the negative electrode during charging, and lithium ions move from the negative electrode to the positive electrode during discharging. However, at the time of discharge, a part of lithium ions may react with a metal material (eg, carbon) of the negative electrode and not move to the positive electrode in some cases. In this case, the lithium ions remaining on the negative electrode do not function as a capacity, and the battery capacity cannot be used sufficiently effectively.

Therefore, a pre-lithiation technique for improving the capacity efficiency by doping a lithium-based material into a negative electrode or a positive electrode in advance has been studied. The prerepetition technique is to improve the charge / discharge efficiency by previously filling the negative electrode or the positive electrode with lithium ions consumed in the early stage of charge / discharge or having lost ion conductivity.

溶 The thermal spraying system 100 according to the first embodiment described below can be used for pre-repetition, that is, for manufacturing an electrode of a lithium ion secondary battery or the like.

<First embodiment>
The thermal spray system 100 according to the first embodiment is configured such that a thermal spray coating can be formed on the substrate W while unwinding and winding the roll-shaped substrate W. Further, the thermal spraying system 100 according to the first embodiment is configured to stabilize the surface of the thermal spray coating formed on the substrate W before winding the substrate W. For this reason, even when the thermal spray coating is made of a highly adhesive material, it is necessary to prevent the thermal spray coating from sticking to the surface of the substrate wound on the thermal spray coating when the substrate W is wound. Can be. Further, the thermal spraying system 100 according to the first embodiment has a differential exhaust mechanism for preventing the material of the thermal spray coating from scattering. Therefore, even when a highly reactive material such as lithium is used, scattering and leakage of the material can be prevented.

基材 The substrate W to be processed in the thermal spraying system is, for example, an electrode sheet, and an electrode material is formed on the electrode sheet. The electrode material is, for example, a carbon material such as activated carbon and graphite. The electrode material is formed to have a width of, for example, about 1 to 100 centimeters (cm). The substrate W can be transported in a state wound in a roll. The substrate W may be a single-sided coated product or a double-sided coated product. In the following description, the surface on one side of the sheet-shaped substrate W is also referred to as a first surface, and the surface on the opposite side to the first surface is also referred to as a second surface. The base material W becomes, for example, a negative electrode of a lithium ion secondary battery. The negative electrode is formed of, for example, a Si-based material, a SiO-based material, or a mixture of carbon and a Si-based or SiO-based material.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the thermal spraying system 100 according to the first embodiment. FIG. 2 is a schematic perspective view illustrating an example of the configuration of the thermal spraying system 100 according to the first embodiment.

The thermal spraying system 100 shown in FIGS. 1 and 2 includes an unloading-side storage chamber (hereinafter, also referred to as a loader chamber) 1, a thermal spray processing chamber 3, a surface processing chamber 5, and a winding-side storage chamber (hereinafter, an unloader chamber). 7). The loader chamber 1, the thermal spray processing chamber 3, the surface processing chamber 5, and the unloader chamber 7 are examples of a first chamber, a second chamber, a third chamber, and a fourth chamber, respectively. A first differential exhaust chamber 2 is provided between the loader chamber 1 and the thermal spray processing chamber 3. In addition, a second differential exhaust chamber 4 is provided between the thermal spray processing chamber 3 and the surface processing chamber 5. A third differential exhaust chamber 6 is provided between the surface treatment chamber 5 and the unloader chamber 7.

ス リ ッ ト A slit S1 is provided between the loader chamber 1 and the first differential exhaust chamber 2 to allow the internal space of the loader chamber 1 and the internal space of the first differential exhaust chamber 2 to communicate with each other. A slit S2 is provided between the first differential evacuation chamber 2 and the thermal spray processing chamber 3 for communicating the internal space of the first differential evacuation chamber 2 with the internal space of the thermal spray processing chamber. A slit S3 is provided between the thermal spray processing chamber 3 and the second differential exhaust chamber 4 to allow the internal space of the thermal spray processing chamber 3 to communicate with the internal space of the second differential exhaust chamber 4. A slit S4 is provided between the differential exhaust chamber 4 and the surface treatment chamber 5 to allow the internal space of the differential exhaust chamber 4 and the internal space of the surface treatment chamber 5 to communicate with each other. A slit S5 is provided between the surface processing chamber 5 and the third differential exhaust chamber 6 to allow the internal space of the surface processing chamber 5 to communicate with the internal space of the third differential exhaust chamber 6. Between the third differential exhaust chamber 6 and the unloader chamber 7, there is provided a slit S6 for communicating the internal space of the third differential exhaust chamber 6 with the internal space of the unloader chamber 7.

The slits S1 to S6 are formed to transport the substrate W between the respective chambers. Therefore, the slits S1 to S6 are formed on the transport path of the base material W. The substrate W is transported from the loader chamber 1 to the unloader chamber 7 through the slits S1 to S6. The slits S1 to S6 are formed in a size and shape such that the electrode material or the thermal spray coating formed on the base material W does not contact the walls of the respective chambers where the slits S1 to S6 are formed. Each of the slits S1 to S6 has substantially the same size and shape. Further, the slits S1 to S6 are arranged at positions that do not hinder the conveyance of the substrate W. In FIG. 1, the transport path of the substrate W is illustrated in a substantially linear shape, but the transport path of the substrate W is not necessarily linear. For example, a guide roller may be provided for transporting the substrate W to control the transport path of the substrate W (see FIG. 2). In this case, the slits S1 to S6 can be arranged at positions corresponding to the transport path of the base material W.

The loader chamber 1 houses the unwinding section 11 on which the substrate W to be processed is set. The unwinding unit 11 is, for example, a roller around which the substrate W to be processed is wound. The roller is, for example, a cylindrical unwinding shaft. The substrate W wound in a roll around the roller is set. The unwinding section 11 can be configured so that the base material W is supported by inserting the center of the roll-shaped base material W into the unwinding shaft.

(4) The loader chamber 1 is connected to the intake / exhaust section 13 through the intake / exhaust port 12 so that the inside can be maintained at a predetermined atmosphere and pressure. The specific configuration of the intake / exhaust section 13 is not particularly limited as long as the inside of the loader chamber 1 can be maintained at a predetermined atmosphere and pressure. The intake / exhaust section 13 includes, for example, a gas supply source, a flow controller (for example, a mass flow controller) for adjusting a gas flow rate, an opening / closing valve, and the like. The intake / exhaust section 13 is configured to maintain the inside of the loader chamber 1 in an inert gas atmosphere, for example. For example, the intake / exhaust section 13 is configured to maintain the inside of the loader chamber 1 in an argon gas atmosphere.

The thermal spray processing chamber 3 accommodates the thermal spray section 31. The thermal spray portion 31 is configured to form a coating on the first surface of the base material W by, for example, thermal spraying of a powder material. The thermal spray unit 31 is, for example, a thermal spray gun configured to form a thermal spray coating by plasma thermal spraying. The thermal spray section 31 has a supply section for supplying the thermal spray material and various gases (for example, a carrier gas and a purge gas), and a mechanism for generating plasma and melting the thermal spray material by the heat of the plasma. The thermal spray unit 31 also has an injection port for injecting the thermal spray jet toward the base material W. The injection port of the thermal spray section 31 is disposed inside the thermal spray processing chamber 3 so as to face the transport path of the base material W. In addition, as long as the injection port is disposed in the room facing the transport path of the base material W, a part or all of the supply unit of the thermal spraying unit 31 and the mechanism for melting the thermal spray material are disposed outside the thermal spray processing chamber 3. May be done.

The thermal spray processing chamber 3 also has an exhaust port 32. The exhaust port 32 is connected to a vacuum pump 33. The air in the thermal spray processing chamber 3 is evacuated by the vacuum pump 33 through the exhaust port 32, and the pressure in the thermal spray processing chamber 3 is reduced.

The surface treatment chamber 5 includes a surface treatment unit 50. The surface treatment unit 50 is configured to stabilize the surface of the coating film formed on the first surface of the base material W in the thermal spray processing chamber 3. That is, the surface treatment unit 50 is configured to perform a surface treatment. The surface treatment unit 50 includes a gas supply unit 51 and a gas discharge unit 52.

The gas supply unit 51 supplies a gas for stabilizing the surface of the coating into the surface treatment chamber 5. For example, in the case of pre-repetition, the gas supply unit 51 supplies oxygen (O ₂ ), carbon dioxide (CO ₂ ), water (H ₂ O) and inert gas to the surface treatment chamber 5 at a predetermined partial pressure. Supply by Note that the gas supply unit 51 need not always supply O ₂ , CO ₂ , H ₂ O, and an inert gas. For example, the gas supply unit 51 may supply only one of O ₂ and CO ₂ .

The partial pressure of the gas supplied by the gas supply unit 51 is, for example, as follows.
O ₂ gas: 0 to 760 Torr
CO ₂ gas: 0 to 760 Torr
H ₂ O: 0 to 760 Torr
Ar gas: 0 to 760 Torr
However, the partial pressure of each gas is adjusted according to the thickness of the film on the substrate W.

The gas exhaust unit 52 exhausts the gas in the surface treatment chamber 5. The specific configurations of the gas supply unit 51 and the gas exhaust unit 52 are not particularly limited.

The surface treatment chamber 5 also has an exhaust port 53. The exhaust port 53 is connected to a vacuum pump 54. The air in the surface treatment chamber 5 is evacuated by the vacuum pump 54 through the exhaust port 53, and the pressure in the surface treatment chamber 5 is reduced. The inside of the surface treatment chamber 5 is controlled to a pressure lower than the atmospheric pressure.

The unloader chamber 7 houses the winding section 71. The winding unit 71 is configured to wind the substrate W after the surface of the coating film formed on the first surface of the substrate W is stabilized. The winding unit 71 is, for example, a roller around which the substrate W to be processed is wound. The roller is, for example, a cylindrical winding shaft. The substrate W that has passed through the thermal spray processing chamber 3 and the surface processing chamber 5 is wound around a roller (the winding section 71).

(4) The unloader chamber 7 is connected to an intake / exhaust section 73 through an intake / exhaust port 72 so that the inside can be maintained at a predetermined atmosphere and pressure. The specific configuration of the intake / exhaust section 73 is not particularly limited as long as the interior of the unloader chamber 7 can be maintained at a predetermined atmosphere and pressure. The intake / exhaust section 73 has, for example, a gas supply source, a flow controller (for example, a mass flow controller) for adjusting the flow rate of gas, and an opening / closing valve. The intake / exhaust section 73 is configured, for example, to maintain the inside of the unloader chamber 7 in an inert gas atmosphere. For example, the suction / exhaust section 73 is configured to maintain the inside of the unloader chamber 7 in an argon gas atmosphere.

The first differential exhaust chamber 2 functions as a differential exhaust mechanism between the loader chamber 1 and the thermal spray processing chamber 3. The first differential exhaust chamber 2 is provided between the loader chamber 1 and the thermal spray processing chamber 3, and is maintained in a higher pressure atmosphere than the thermal spray processing chamber 3. The first differential exhaust chamber 2 is connected to a gas supply unit 22 via, for example, an intake port 21. Further, the first differential exhaust chamber 2 is connected to an exhaust unit 24 via, for example, an exhaust port 23. The gas supply unit 22 supplies a predetermined gas to the first differential exhaust chamber 2 via the intake port 21. Further, the exhaust unit 24 exhausts the inside of the first differential exhaust chamber 2 through the exhaust port 23.

As described above, since the first differential exhaust chamber 2 includes the gas supply unit 22 and the exhaust unit 24, the internal atmosphere of the loader chamber 1 and the internal atmosphere of the thermal spray processing chamber 3 are prevented from flowing. I do. The first differential exhaust chamber 2 functions as a separation layer between the loader chamber 1 and the thermal spray processing chamber 3 as it were. In addition, the first differential exhaust chamber 2 prevents the powder material scattered by thermal spraying in the thermal spray processing chamber 3 from leaking into the loader chamber 1. The first differential exhaust chamber 2 only needs to be able to prevent the flow of the internal atmosphere of the loader chamber 1 and the thermal spray processing chamber 3 by differential exhaust and to prevent leakage of the thermal spray material. The configuration of the unit 24 and the like is not particularly limited.

The second differential exhaust chamber 4 functions as a differential exhaust mechanism between the thermal spray processing chamber 3 and the surface processing chamber 5. The second differential exhaust chamber 4 is provided between the thermal spray processing chamber 3 and the surface processing chamber 5, and is maintained in a higher pressure atmosphere than the thermal spray processing chamber 3. The second differential exhaust chamber 4 is connected to a gas supply unit 42 via, for example, an intake port 41. Further, the second differential exhaust chamber 4 is connected to an exhaust unit 44 via, for example, an exhaust port 43. The gas supply unit 42 supplies a predetermined gas to the second differential exhaust chamber 4 via the intake port 41. Further, the exhaust unit 44 exhausts the inside of the second differential exhaust chamber 4 through the exhaust port 43.

As described above, since the second differential exhaust chamber 4 includes the gas supply unit 42 and the exhaust unit 44, the internal atmosphere of the thermal spray processing chamber 3 and the internal atmosphere of the surface processing chamber 5 can be circulated. To prevent. The second differential exhaust chamber 4 functions as a so-called separation layer between the thermal spray processing chamber 3 and the surface processing chamber 5. Further, the second differential exhaust chamber 4 prevents the powder material scattered by thermal spraying in the thermal spray processing chamber 3 from leaking to the surface processing chamber 5. The second differential evacuation chamber 4 only needs to be capable of preventing the flow of the internal atmosphere of the thermal spray processing chamber 3 and the surface processing chamber 5 by differential exhaust and preventing leakage of the thermal spray material. The configuration of the exhaust unit 44 and the like is not particularly limited.

The third differential exhaust chamber 6 functions as a differential exhaust mechanism between the surface treatment chamber 5 and the unloader chamber 7. The third differential exhaust chamber 6 is provided between the surface processing chamber 5 and the unloader chamber 7 and is maintained in a higher pressure atmosphere than the surface processing chamber 5. The third differential exhaust chamber 6 is connected to a gas supply unit 62 via, for example, an intake port 61. Further, the third differential exhaust chamber 6 is connected to an exhaust unit 64 via, for example, an exhaust port 63. The gas supply unit 62 supplies a predetermined gas to the third differential exhaust chamber 6 via the intake port 61. Further, the exhaust part 64 exhausts the inside of the third differential exhaust chamber 6 through the exhaust port 63.

As described above, since the third differential exhaust chamber 6 includes the gas supply unit 62 and the exhaust unit 64, the internal atmosphere of the surface treatment chamber 5 and the internal atmosphere of the unloader chamber 7 are prevented from flowing. . The third differential exhaust chamber 6 functions as a separation layer between the surface treatment chamber 5 and the unloader chamber 7, so to speak. The third differential exhaust chamber 6 only needs to be able to prevent the flow of the internal atmosphere of the surface treatment chamber 5 and the unloader chamber 7 by differential exhaust, and the configurations of the gas supply unit 62 and the exhaust unit 64 are particularly limited. Not done.

The first differential exhaust chamber 2, the second differential exhaust chamber 4, and the third differential exhaust chamber 6 can be similarly configured. The atmosphere in each chamber is preferably an inert gas (eg, argon) atmosphere because the atmosphere does not react with the lithium powder and the surface after the surface treatment can be maintained in an inactive state.

The thermal spraying system 100 further includes a control device 8. The control device 8 includes a control unit 81, an operation unit 82, and a storage unit 83.

The control unit 81 controls the operation of each unit of the thermal spraying system 100.

The operation unit 82 receives an input operation of a command for operating the thermal spraying system 100 by an operator, and the like. The operation unit 82 is, for example, a keyboard, a display, a touch panel, or the like.

The storage unit 83 stores a program for controlling the operation of each unit of the thermal spray system 100.

The control device 8 is, for example, a computer including a CPU (Central Processing Unit) and a memory. The storage unit 83 stores programs for controlling various processes executed in the thermal spraying system 100. The control unit 81 controls the operation of the thermal spraying system 100 by reading and executing the program stored in the storage unit 83. In addition, the control unit 81 may be configured to read and execute a program stored in the storage unit 83 to maintain the temperature and humidity in the room where the thermal spraying system 100 is disposed at predetermined values. Some thermal spray materials react to temperature and humidity, such as those that ignite when contacted with water. Therefore, the temperature and humidity in the room where the thermal spraying system 100 is arranged may be controlled by the control device 8 in accordance with the characteristics of the thermal spraying material to be used. Further, the flow rate of the gas supplied to and exhausted from each of the chambers 1 to 7 provided in the thermal spray system 100 and the timing of supply and exhaust may be controlled by the control device 8.

Note that such a program is recorded on a computer-readable storage medium, and may be installed in the storage unit 83 from the storage medium. Examples of the storage medium readable by a computer include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

FIG. 2 shows an example of a configuration of the thermal spraying system 100 according to the first embodiment. In the example of FIG. 2, each of the first differential pumping chamber 2, the second differential pumping chamber 4, and the third differential pumping chamber 6 is connected to a vacuum pump on the ceiling side of the chamber, so that the inside of the chamber is internally connected. Pressure is controlled. As described above, the method for realizing the differential exhaust in each differential exhaust chamber is not particularly limited. Further, the base material W is supported by a plurality of guide rollers. In the example of FIG. 2, the guide rollers are arranged horizontally. However, the arrangement position of the guide roller is not limited to this, and the thermal spraying system 100 may be configured to arrange the guide roller in other chambers other than the surface treatment chamber 5 to guide the base material W. As such, the details of the thermal spray system 100 can vary.

<Example of Process Flow in Thermal Spray System 100>
FIG. 3 is a flowchart illustrating an example of the flow of the thermal spraying process in the thermal spraying system 100 according to the first embodiment.

In the thermal spraying system 100 configured as described above, the thermal spraying process starts under the control of the control device 8. First, the roll-shaped substrate W is carried into the loader room 1 and set on the unwinding section 11 (step S31). Next, by executing a program or the like stored in the storage unit 83, the atmosphere, temperature, humidity, and the like of each room of the thermal spraying system 100 are controlled. Then, the base material W is unwound from the unwinding unit 11, passes through the first differential evacuation chamber 2 through the transport path, and is transported to the thermal spray processing chamber 3. In the thermal spray processing chamber 3, the thermal spray section 31 sprays the molten powder material onto the surface of the base material W to form a coating (thermal spray processing, step S32). The substrate W on which the coating is formed exits the thermal spray processing chamber 3, passes through the second differential exhaust chamber 4, and enters the surface processing chamber 5. In the surface treatment chamber 5, the surface of the coating film on the substrate W is stabilized, that is, inactivated, by O ₂ , CO ₂ , H ₂ O and the inert gas supplied from the gas supply unit 51 (surface treatment). , Step S33). The base material W having a stabilized film surface exits from the surface treatment chamber 5, passes through the third differential exhaust chamber 6, is wound by the winding unit 71 in the unloader chamber 7, and becomes a roll again (step). S34). This is the flow of the thermal spraying process according to the first embodiment.

<Surface treatment>
Next, the surface treatment in the surface treatment chamber 5 will be further described with reference to FIGS. 4A and 4B. FIG. 4A is a diagram for explaining an example of a coating formed by the thermal spray processing section 31 of the thermal spray system 100 according to the first embodiment. FIG. 4B is a diagram for describing an example of a stabilization layer formed by the surface treatment unit 50 of the thermal spraying system 100 according to the first embodiment.

Here, it is assumed that a powdery lithium metal material is used as a thermal spraying material for prelithiation. Since lithium metal is a material that easily adheres, after a lithium metal film is formed on the substrate W, the substrate W is rolled into a roll shape, and the portion where the surface of the lithium metal film contacts the substrate W In this case, the coating film and the substrate W adhere to each other, and it is difficult to extend the film into a sheet. Therefore, in order to prevent the lithium metal coating and the substrate W from sticking to each other, it is conceivable to execute a process for stabilizing the surface of the lithium metal coating. However, when used in prelithiation, it is preferred that the lithium metal coating be kept as active as possible. Therefore, it is desirable to stabilize only the surface of the lithium metal coating.

FIG. 4A shows a state in which a layer of carbon C (or graphite) is formed as an electrode material on a base material W, and then carried into the thermal spraying system 100 to form a thermal spray coating L of lithium metal in the thermal spray processing chamber 3. . In the state of FIG. 4A, a carbon film C is formed on a base material W, and a film L of lithium metal is formed on the carbon film C held by a binder B.

After the film L of FIG. 4A is formed, the substrate W is transported to the surface treatment chamber 5. Then, the atmosphere (O ₂ , CO ₂ , H ₂ O, inert gas) in the surface treatment chamber 5 reacts with the coating surface, and a few nanometers (nm) of lithium oxide, lithium carbonate or a mixture thereof is formed on the coating surface. Is formed. The combination of gases supplied into the surface treatment chamber 5 is, for example, H ₂ O and an inert gas, or CO ₂ , H ₂ O and an inert gas, or O ₂ , H ₂ O and an inert gas, Or, CO ₂ , O ₂ , H ₂ O and an inert gas. The formed film functions as a stabilizing layer. Therefore, even after the base layer W is wound into a roll after the stabilization layer is formed, the surface of the lithium coating is prevented from sticking to the base layer W.

<Processing conditions etc.>
By the way, as described above, if the entire lithium coating is stabilized during the surface treatment, the electrode capacity cannot be effectively used. Therefore, the present inventors conducted experiments by changing the partial pressure of each gas used in the surface treatment. FIG. 5 is a table showing experimental results regarding surface treatment conditions according to the first embodiment. In the experiment, the transport speed of the substrate W was 1 to 20 m / min, the width of the lithium coating was 5 to 50 cm, and the width of the current collector foil was 5 to 50 cm.

In addition, changes occurring in the lithium coating in the experiment were observed by a scanning electron microscope (SEM) and an X-ray photoelectric spectroscopy (XPS). As a result, as shown in FIG. 5, when the partial pressure of water (H ₂ O) was less than 0.01, no change was observed in the lithium coating. On the other hand, when the partial pressure of water was 0.05 or more, and further 0.45 or more, stabilization of the surface of the lithium coating was recognized regardless of other gas treatment conditions. From these facts, the inventors concluded that the surface treatment conditions suitable for prelithiation are such that the partial pressure of water is 0.01 or more, preferably 0.05 or more. If the partial pressure of water is too high, the entire lithium coating is stabilized. Therefore, the partial pressure of water is at a level at which the surface of the lithium coating is stabilized, and is preferably as low as possible. The thickness of the surface of the coating to be stabilized is preferably, for example, 0.1% or more of the thickness of the lithium coating.

<Modification>
In the first embodiment, the differential exhaust chambers (2, 4, 6) are provided between the loader chamber 1, the thermal spray processing chamber 3, the surface processing chamber 5, and the unloader chamber 7, respectively. However, the present invention is not limited to this, and the differential exhaust chamber may be provided only between specific chambers. For example, the thermal spraying system 100 can be configured so that the differential exhaust chamber is not provided next to the loader chamber 1 and the unloader chamber 7. In this case, the thermal spraying system 100 appropriately controls the pressure difference and the flow of air in the room to prevent mixing of the atmosphere between the rooms.

In the thermal spray processing chamber 3, highly reactive powder material such as lithium is handled, and in the surface processing chamber 5, H ₂ O is supplied into the chamber. There is. For this reason, the differential exhaust chamber may be always provided between the thermal spray processing chamber 3 and the surface processing chamber 5.

In addition, the exhaust mechanism of each chamber is configured so that the internal pressure and atmosphere of each chamber can be adjusted separately. However, a common exhaust device (vacuum pump or the like) may be provided if there is no safety problem due to gas mixing.

<Effects of First Embodiment>
The thermal spraying system according to the first embodiment includes a thermal spraying unit, a surface treatment unit, and a winding unit. The thermal spray portion is configured to form a coating on the first surface of the substrate by thermal spraying the powder material. The surface treatment is configured to stabilize the surface of the coating. The winding unit is configured to wind the substrate after stabilization of the surface of the coating. For this reason, even if the coating formed by thermal spraying has high tackiness, the surface can be stabilized and the winding can be performed without fear of sticking. For this reason, the base material on which the coating has been formed can be wound up without deteriorating the quality of the coating formed by thermal spraying.

In addition, in the thermal spraying system according to the first embodiment, the thermal spraying unit sprays a lithium powder material to form a lithium coating on the first surface of the base material. The surface treatment unit stabilizes the surface of the lithium coating by changing the surface of the lithium coating to lithium oxide, lithium carbonate, or a mixture of lithium oxide and lithium carbonate. For this reason, a thermal spray system can be used for pre-lithiation.

Further, in the thermal spraying system according to the first embodiment, the surface treatment unit treats the surface of the lithium coating with H ₂ O and an inert gas, or CO ₂ , O ₂ , H ₂ O and an inert gas, or O _{2, H 2} O, and the inert gas _or,, CO _2, O _2, stabilized by exposure to _{H 2} O and an inert gas. In the surface treatment section, the partial pressure of H ₂ O for exposing the surface of the lithium coating is set to 0.01 Torr or more. Thus, the thermal spray system can stabilize the surface of the lithium coating a few nanometers and keep the rest active. For this reason, the thermal spraying system can effectively realize the pre-repetition.

溶 The thermal spraying system according to the first embodiment includes a first chamber, a second chamber, a third chamber, and a fourth chamber. In the first chamber, the base material before thermal spraying is arranged in a wound state. The second chamber is provided with a thermal spray section. A surface treatment unit is provided in the third chamber. The fourth chamber is provided with a winding unit. The substrate is transported from the first chamber to the fourth chamber through slits formed in each of the first, second, third, and fourth chambers. For this reason, the thermal spraying system can perform the thermal spraying process and the surface treatment in separate rooms, and can easily control the processing conditions of each process.

溶 Further, the thermal spraying system according to the first embodiment further includes a first working exhaust chamber provided between the first chamber and the second chamber and maintained at a higher pressure atmosphere than the second chamber. For this reason, the thermal spray system can prevent the powder material used for the processing in the second chamber from leaking into the first chamber.

The thermal spraying system according to the first embodiment further includes a second working exhaust chamber provided between the second chamber and the third chamber and maintained at a higher pressure atmosphere than the second chamber. For this reason, the thermal spray system can prevent the powder material and the like used for the processing in the second chamber from leaking into the third chamber. Further, when the lithium powder is used for the processing in the second chamber, the thermal spraying system can prevent the fire from coming into contact with the water used for the processing in the third chamber.

The thermal spray system according to the first embodiment further includes a third working exhaust chamber provided between the third chamber and the fourth chamber and maintained in a higher-pressure atmosphere than the third chamber. In this manner, the thermal spraying system can execute processing by individually controlling the state of each chamber. Further, the thermal spray system can prevent the internal atmospheres of the respective chambers from being mixed.

溶 In addition, the thermal spraying system according to the first embodiment executes the thermal spraying process and the surface treatment in separate rooms. For this reason, lithium carbonate and lithium oxide are not generated excessively, and the absolute amount of active lithium metal that contributes to the improvement of the efficiency of the lithium secondary battery does not decrease. In addition, the gas supplied for stabilizing the surface does not remain in the room and does not reduce the absolute amount of active lithium metal. Further, the gas supplied for stabilizing the surface does not need to be exhausted for the thermal spraying process, so that a decrease in throughput can be suppressed.

<Second embodiment>
The thermal spraying system 100 according to the first embodiment forms a coating by thermal spraying on the first surface of the base material W. However, the present invention is not limited thereto, and the thermal spraying system 100 may be configured to form a coating by thermal spraying on the first and second surfaces of the base material W.

6A, 6B, and 6C are diagrams illustrating Configuration Examples 1 to 3 of the thermal spraying system according to the second embodiment.

6A includes a loader chamber 1A, a first differential exhaust chamber 2A, a first thermal spray processing chamber 3A, a second differential exhaust chamber 4A, and a first surface processing chamber 5A. And a second thermal processing chamber 6A, a second surface processing chamber 7A, and a fourth differential exhaust chamber 8A. The configuration and function of each unit are the same as in the first embodiment.

However, in the thermal spraying system 100A shown in FIG. 6A, after the first surface of the substrate W is processed in the first thermal spray processing chamber 3A and the first surface processing chamber 5A, the second surface of the substrate W is processed. Is processed in the second thermal processing chamber 6A and the second surface processing chamber 7A. For this reason, the thermal spraying system 100A of FIG. 6A has two thermal processing chambers (first thermal processing chamber 3A, second thermal processing chamber 6A) and two surface processing chambers (first surface processing chamber 5A, second thermal processing chamber 5A). Surface treatment chamber 7A). The first thermal spray processing chamber 3A and the second thermal spray processing chamber 6A are arranged in a two-story structure. Further, in the thermal spraying system 100A of FIG. 6A, a loader chamber 1A in which a loader chamber and an unloader chamber are integrated into one is provided. In the thermal spraying system 100A, the transport direction of the substrate W is reversed in the first surface treatment chamber 5A, and the substrate W is transported such that the second surface faces upward.

In the example of FIG. 6A, the second differential evacuation chamber 4A is configured so that both the base material W carried into the first surface treatment chamber 5A and the base material W carried out from the first surface treatment chamber 5A are used. pass. However, the present invention is not limited thereto, and the differential exhaust chamber through which the base material W carried into the first surface treatment chamber 5A passes, and the differential exhaust chamber through which the base material W carried out from the first surface treatment chamber 5A passes. The chamber may be provided separately.

The thermal spray system 100B shown in FIG. 6B includes a loader chamber 1B, a first differential exhaust chamber 2B, a thermal spray processing chamber 3B, a second differential exhaust chamber 4B, a surface processing chamber 5B, and an unloader chamber 6B. , Is provided. The thermal spray system 100B shown in FIG. 6B is configured to process both the first surface and the second surface of the substrate W simultaneously. The base material W conveyed from the loader chamber 1B passes between the spray parts 31B arranged so as to sandwich the conveyance path of the base material W from two directions in the thermal spray processing chamber 3B. At this time, a film is formed on both the first surface and the second surface of the base material W. Then, after passing through the second differential evacuation chamber 4B, the base material W enters the surface treatment chamber 5B, and at the same time, the surface treatment of the coating on the first surface and the second surface is realized. In the example of FIG. 6B, the differential exhaust chamber is not disposed at the subsequent stage of the surface treatment chamber 5B, but the differential exhaust chamber may be modified to be disposed. In the example of FIG. 6B, a guide roller is provided in the surface treatment chamber 5B to control the transport direction of the base material W. However, when the quality of the coating on the substrate W is affected, the position of the guide roller may be changed so that the substrate W comes into contact with the guide roller after the surface of the coating is stabilized in the surface treatment chamber 5B.

溶 The thermal spraying system 100C shown in FIG. 6C includes a loader chamber 1C, a first differential exhaust chamber 2C, a first thermal spray processing chamber 3C, a second differential exhaust chamber 4C, and a first surface processing chamber 5C. Further, the thermal spray system 100C includes a third differential exhaust chamber 6C, a second thermal spray processing chamber 7C, a fourth differential exhaust chamber 8C, a second surface processing chamber 9C, and an unloader chamber 10C. The components included in the thermal spraying system 100C of FIG. 6C are substantially the same as those of the thermal spraying system 100A shown in FIG. 6A, except that a part having a two-story structure is reduced. Note that, also in the example of FIG. 6C, a differential exhaust chamber may be disposed downstream of the second surface treatment chamber 9C.

Thus, the thermal spray system according to the embodiment can be arranged in buildings having various structures by devising the arrangement of each room.

<Third embodiment>
The thermal spray system according to the above embodiment may further include a cooling mechanism for suppressing damage to the base material W due to heat during thermal spraying. Hereinafter, as a third embodiment, a thermal spraying system 100D including the cooling mechanism 34 will be described.

FIG. 7 is a diagram for explaining a cooling mechanism 34 provided in a thermal spraying system 100D according to the third embodiment. Note that the thermal spraying system 100D according to the first embodiment is the same as the thermal spraying system 100 according to the first embodiment except that the thermal spraying system 100D according to the third embodiment includes a cooling mechanism 34 that suppresses the influence of heat generated by thermal spraying in the thermal spraying processing chamber 3D. It has a similar configuration. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description and / or illustration is omitted.

冷却 The cooling mechanism 34 shown in FIG. 7 includes a cooling roller 35, a guide roller 36, and a refrigerant supply unit 37.

(4) The cooling roller 35 is disposed below the injection port of the thermal spray section 31 in the thermal spray processing chamber 3D and on the transport path of the base material W. The cooling roller 35 has a refrigerant passage 35A through which the refrigerant flows. The cooling roller 35 has a width and a diameter capable of transporting the base material W unwound from the loader chamber 1. Further, the diameter of the cooling roller 35 is formed to a size that satisfies the cooling conditions described later.

The guide roller 36 is disposed on the transport path of the base material W in the thermal spray processing chamber 3D. The guide roller 36 is disposed closer to the loader chamber 1 than the cooling roller 35 on the transport path of the base material W. The guide roller 36 increases the transport distance of the substrate W on the cooling roller 35 by changing the transport direction of the substrate W before the substrate W reaches the cooling roller 35. For example, as shown in FIG. 7, the guide roller 36 is arranged at a position closer to the second differential exhaust chamber 4 than the cooling roller 35. Even if the guide roller 36 is not provided, the guide roller 36 may not be provided if the transport distance of the base material W on the cooling roller 35 can satisfy the cooling condition described later. Further, the relative positional relationship between the guide roller 36 and the cooling roller 35 is not particularly limited. FIG. 7 illustrates one guide roller 36, but the number of guide rollers 36 is not particularly limited. An arbitrary number of guide rollers 36 can be arranged to adjust the transport distance of the base material W on the cooling roller 35.

The refrigerant supply unit 37 supplies the refrigerant to the refrigerant passage 35A of the cooling roller 35. The specific configuration of the refrigerant supply unit 37 is not particularly limited. The type of the refrigerant supplied by the refrigerant supply unit 37 is not particularly limited, and may be, for example, tap water adjusted to a predetermined temperature.

搬 送 With reference to FIG. 7, conveyance of the base material W in the thermal spraying system 100D will be described. In the thermal spraying system 100D, the base material W unwound from the unwinding section 11 in the loader chamber 1 passes through the first working exhaust chamber 2 and enters the thermal spray processing chamber 3D. In the thermal spray processing chamber 3D, the base material W is first wound upward from below the guide roller 36. At this time, if the transport direction from the loader chamber 1 to the unloader chamber 7 is the forward direction, the transport direction of the substrate W wound around the guide roller 36 is opposite to the forward direction. Thereafter, the base material W is wound upward from below the cooling roller 35 disposed above the guide roller 36, and the transport direction becomes the forward direction again. Then, the base material W passes from the thermal spray processing chamber 3D, passes through the second differential exhaust chamber 4, the surface treatment chamber 5, and the third working exhaust chamber 6, and is taken up by the take-up portion 71 in the unloader chamber 7.

(4) When the base material W is conveyed on the cooling roller 35, the molten powder material is jetted onto the base material W by the thermal spraying part 31 disposed above the cooling roller 35 to form a film. At this time, the surface of the substrate W is heated by the molten powder material. In the third embodiment, the coolant flows through the cooling roller 35 during the thermal spraying process, whereby the temperature rise of the base material W on the cooling roller 35 is suppressed.

<Cooling conditions>
The present inventors conducted experiments to examine cooling conditions for suppressing a temperature rise of the base material W in the thermal spraying system 100D, and obtained the following knowledge.
(1) Since the heat capacity increases as the diameter of the cooling roller 35 increases, the temperature of the base material W transported on the cooling roller 35 can be reduced.
(2) The larger the contact area between the cooling roller 35 and the substrate W conveyed on the cooling roller 35, the more the temperature rise of the substrate W can be suppressed.
(3) The greater the amount of the refrigerant flowing in the cooling roller 35, the greater the amount of heat removal, and thus the degree of increase in the temperature of the base material W can be suppressed.
(4) The temperature of the base material W changes due to the change in the temperature of the coolant flowing through the cooling roller 35, but the increase in the temperature of the base material W does not change.

(Experiment 1: Effect of refrigerant flow rate on cooling performance)
In Experiment 1, the flow rate of the refrigerant was changed while the transport speed of the base material W was fixed, and the influence of the change in the flow rate of the refrigerant was examined. Specifically, the transport speed and the flow rate were set as follows.
-Transfer speed of the substrate W: 0.1 m / min-Flow rate of the refrigerant: 2 L / min, 5 L / min, 10 L / min As a result, regardless of the temperature of the refrigerant, the temperature of the substrate W starts the thermal spraying process. It was found that it was stabilized in about 20 to 30 minutes after that, and then stabilized. For example, when the flow rate of the refrigerant was 10 L / min, the temperature of the base material W was stabilized at a temperature lower by about 5 ° C. to 7 ° C. than in the case of 2 L / min. From this, it was found that the larger the flow rate of the refrigerant, the more stable the temperature of the base material W at a low temperature, but the more stable the temperature of the base material W regardless of the flow rate of the refrigerant.

(Experiment 2: Influence of substrate transfer speed on cooling performance)
In Experiment 2, the effect of the transport speed of the substrate W on the cooling performance was measured. Specifically, Experiment 2 was performed under the following conditions.
-Transport speed of the substrate W: 1 m / min, 3 m / min, 5 m / min, 10 m / min, 20 m / min-Flow rate of refrigerant: 2 L / min, 5 L / min, 10 L / min The substrate W was heated by the heater while transporting the substrate W. Five minutes after the start of heating, the temperature of the substrate W was measured. In the experiment, it was found that when the transport speed of the base material W was high (for example, 20 m / min), the hot air emitted from the thermal spray portion 31 due to the movement of the base material W flowed downstream. It was also found that the temperature of the base material W increased on the downstream side due to this. Therefore, in order to prevent the influence of hot air accompanying the transport of the substrate W, a further experiment was conducted by adding a mechanism in which hot air did not flow downstream. As a result, the result was obtained that the temperature of the substrate W decreased as the transport speed of the substrate W increased and the flow rate of the refrigerant increased.

(Experiment 3: Effect of refrigerant temperature on cooling performance)
In Experiment 3, the temperature of the substrate W was measured while changing the temperature of the refrigerant.
・ Transport speed of the substrate W: 1 m / min, 5 m / min, 20 m / min ・ Temperature of refrigerant: 20 ° C., 60 ° C.
As a result, it was found that the lower the temperature of the refrigerant, the lower the temperature of the substrate W. However, there was no particular difference in the behavior of the temperature change with time depending on the temperature of the refrigerant. For this reason, it turned out that the temperature of the base material W can be adjusted by the temperature of the refrigerant.

From the above, the diameter of the cooling roller 35, the contact distance (transport distance) between the cooling roller 35 and the substrate W, the flow rate of the refrigerant, What is necessary is just to set the conveyance speed of the base material W in advance as a cooling condition. When the set cooling conditions are satisfied, the temperature of the base material W does not increase even if the thermal spraying process is continued for a long time.

冷却 By setting the cooling conditions in this way, sufficient cooling performance can be realized even when city water is used as the refrigerant, and processing of the base material W at a desired temperature can be realized.

実 施 The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. Indeed, the above embodiments can be embodied in various forms. The above embodiments may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

100,100D thermal spray system 1 loader room (first room)
DESCRIPTION OF REFERENCE NUMERALS 11 Unwinding part 12 Intake / exhaust port 13 Intake / exhaust part 2 First differential exhaust chamber 21 Intake port 22 Gas supply part 23 Exhaust port 24 Exhaust part 3, 3D thermal spray processing chamber (second chamber)
Reference Signs List 31 spraying part 32 exhaust port 33 vacuum pump 34 cooling mechanism 35 cooling roller 35A refrigerant passage 36 guide roller 37 refrigerant supply part 4 second differential exhaust chamber 41 intake port 42 gas supply part 43 exhaust port 44 exhaust part 5 surface treatment Room (Room 3)
Reference Signs List 50 surface treatment section 51 gas supply section 52 gas discharge section 53 exhaust section 54 vacuum pump 6 third differential exhaust chamber 61 intake port 62 gas supply section 63 exhaust port 64 exhaust section 7 unloader chamber (fourth chamber)
71 Rewinding part 72 Intake / exhaust port 73 Intake / exhaust part 8 Control device 81 Control part 82 Operation part 83 Storage part W Base material

Claims (10)

A thermal spray portion configured to form a coating on the first surface of the substrate by thermal spraying the powder material;
A surface treatment unit configured to stabilize the surface of the coating,
After stabilization of the surface of the coating, a winding unit configured to wind the substrate,
Thermal spraying system comprising: The spraying unit sprays a lithium powder material to form a lithium coating on the first surface of the base material,
The surface treatment unit stabilizes the surface of the lithium coating by changing the surface of the lithium coating to lithium oxide, lithium carbonate, or a mixture of lithium oxide and lithium carbonate,
The thermal spray system according to claim 1. The surface treatment unit treats the surface of the lithium coating with H ₂ O and an inert gas, or CO ₂ , H ₂ O and an inert gas, or O ₂ , H ₂ O and an inert gas, or CO 2 _2, stabilized by exposure to O 2, _H 2 _O, and the inert gas, spraying system of claim 2. 4. The thermal spraying system according to claim 3, wherein the surface treatment unit sets a partial pressure of H ₂ O that exposes a surface of the lithium coating to 0.01 Torr or more. 5. A first chamber in which the base material before thermal spraying is arranged in a wound state,
A second chamber in which the thermal spray section is provided;
A third chamber provided with the surface treatment unit;
A fourth chamber in which the winding section is provided;
With
The said base material is conveyed from the said 1st chamber to the said 4th chamber through the slit formed in each of the said 1st chamber, the said 2nd chamber, the said 3rd chamber, and the said 4th chamber. The thermal spraying system according to any one of claims 1 to 4. 6. The thermal spraying system according to claim 5, further comprising a first working exhaust chamber provided between the first chamber and the second chamber and maintained in a higher-pressure atmosphere than the second chamber. 7. 7. The thermal spraying system according to claim 5, further comprising a second working exhaust chamber provided between the second chamber and the third chamber and maintained in a higher-pressure atmosphere than the second chamber. 8. 8. The apparatus according to claim 5, further comprising a third working exhaust chamber provided between the third chamber and the fourth chamber and maintained in a higher-pressure atmosphere than the third chamber. 9. Thermal spray system. Spraying a powder material to form a coating on the first surface of the substrate,
A surface treatment step of stabilizing the surface of the coating,
After stabilization of the surface of the coating, a winding step of winding the substrate,
Thermal spraying method including. Forming a lithium coating on the first surface of the substrate by spraying the lithium powder material;
Stabilizing by changing the surface of the lithium coating to lithium oxide, lithium carbonate or a mixture of lithium oxide and lithium carbonate,
A method for manufacturing a lithium secondary battery, comprising winding the substrate after stabilizing the lithium coating.

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