JP2017047393A - Coating device and electrode manufactured by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device which enables easy control of an amount of slurry discharged from a die head, obtains a desired coating film, and contributes to performance improvement of a lithium ion secondary battery.SOLUTION: A coating device 1 of the invention includes: a die head 60 having a discharge port 65 for discharging slurry 5 to a sheet base material 3 transported by a roller; a coating valve which controls the slurry 5 supplied to the die head 60; an air damper 80 which is provided at the die head 60 and has a damper chamber communicating with the discharge port 65 and filled with air; and an electromagnetic valve 70 disposed between the air damper 80 and the discharge port 65.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating apparatus for applying a slurry such as an active material to a sheet base material when manufacturing an electrode of a laminated lithium ion secondary battery, and an electrode manufactured by the coating apparatus.

  Lithium ion secondary batteries can be reduced in size and weight and have a high energy density, so they are used for portable device power supplies, electric bicycles, electric vehicles, and other commercial power backup applications. Various proposals for improving performance can be seen.

  In a lithium ion secondary battery, a slurry containing active material particles is applied continuously or intermittently to the surface of a strip-shaped current collector, dried, and then compressed, so that the active material particles mutually and the active material particles The battery performance is improved by reducing the electrical contact resistance with the current collector and further increasing the energy density.

  Taking a lithium ion secondary battery as an example, when the negative electrode active material layer is mainly composed of carbonaceous particles such as graphite, the positive electrode active material layer contains lithium such as lithium manganese composite oxide particles. A composite oxide is used.

  In addition, as for a coating apparatus such as a die coater used in a process of coating a slurry containing active material particles on a sheet substrate such as a current collector, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2015-26471). Is disclosed.

Japanese Patent Laying-Open No. 2015-26471

  Here, the outline of the structure which performs intermittent coating using the conventional coating apparatus 1 is demonstrated. FIG. 8 is a diagram schematically showing a conventional coating apparatus 1.

  As shown in FIG. 8, a die head 60, a coating valve 40 connected to the die head 60, a pump 30, and a tank 20 for storing the slurry 5 are provided in the flow path of the slurry 5 of the coating apparatus 1 in intermittent coating. Have. Moreover, although it has the return valve 50 located between the said tank 20 and the coating valve 40, it is preferable to use a motor valve about the coating valve 40 at least.

  The motor valve can accurately change the opening and closing of the valve even during the application of the slurry 5, and by controlling the flow path of the slurry in combination with the operation of the return valve 50, a complicated application state can be realized. It becomes possible.

  According to the coating apparatus 1 as described above, by controlling the opening and closing of the coating valve 40, the slurry 5 to be coated from the die head 60 is controlled, and the coating film 7 is intermittently formed on the sheet substrate 3. be able to. FIG. 9 is a view showing a coating film 7 applied to the sheet base material 3 by the coating apparatus 1. FIG. 10 is a diagram showing the cutting out of the electrode from the sheet base material 3. An electrode such as a lithium ion secondary battery can be obtained by cutting out along the dotted line shown in FIG.

  By the way, particularly when aqueous slurry is used, when the coating valve 40 is opened, the pressure of the slurry 5 in the die head 60 fluctuates or pulsation is generated in the pressure of the slurry 5. There is a problem that it becomes difficult to control the coating amount of the slurry 5 coated from 60.

  Furthermore, if the application amount of the slurry 5 applied on the sheet substrate 3 cannot be controlled, the desired coating film 7 cannot be obtained, and the performance of the lithium ion secondary battery will be adversely affected. There was also a problem.

  The present invention solves the above problems, the coating apparatus according to the present invention includes a head having a coating outlet for discharging slurry to a sheet substrate conveyed by a roller; A coating valve for controlling slurry to be supplied to the head; a damper provided in the head; and a damper chamber communicating with the coating outlet; the damper chamber being filled with air; the air damper and the coating outlet And an electromagnetic valve disposed between the two.

  In addition, the coating apparatus according to the present invention includes a head having a coating outlet for discharging slurry to a sheet base material conveyed by a roller, a coating valve for controlling slurry supplied to the head, An air damper that is provided between the coating valve and the head and has a damper chamber that communicates with the coating outlet and is filled with air, and is disposed between the air damper and the coating outlet. And a solenoid valve.

  Moreover, the electrode which concerns on this invention is an electrode manufactured by the coating apparatus described above.

  The coating apparatus according to the present invention includes a damper chamber that communicates with a coating outlet of a head, an air damper that is filled with air in the damper chamber, and an electromagnetic valve that is disposed between the air damper and the coating outlet. According to such a coating apparatus according to the present invention, since the air damper absorbs fluctuations and pulsations of the slurry pressure in the die head accompanying the operation of the coating valve, the coating is applied from the die head. The amount of slurry applied can be easily controlled, a desired coating film can be obtained, and the performance of the lithium ion secondary battery can be improved.

It is a figure showing typically coating device 1 concerning an embodiment of the present invention. It is a perspective view of die head 60 used with coating device 1 concerning an embodiment of the present invention. It is a figure explaining the effect of the solenoid valve 70 used together with the air damper 80 of the coating device 1 which concerns on embodiment of this invention. It is a figure which shows the mode of the coating film | membrane 7 on the sheet | seat base material 3 formed by the intermittent coating by the coating device 1 which concerns on embodiment of this invention. It is a figure explaining the opening-and-closing timing of the coating valve 40, the electromagnetic valve 70, and the return valve 50 in the coating apparatus 1 which concerns on embodiment of this invention. It is a figure explaining the effect of the air damper 80 of the coating apparatus 1 which concerns on embodiment of this invention. It is a figure which shows typically the coating apparatus 1 which concerns on other embodiment of this invention. It is a figure which shows the conventional coating device 1 typically. It is a figure which shows the coating film 7 coated on the sheet | seat base material 3 by the coating apparatus 1. FIG. It is a figure which shows cutting out of the electrode from the sheet | seat base material 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a coating apparatus 1 according to an embodiment of the present invention. The embodiments of the present invention are not limited to the embodiments described below, and modifications such as design changes can be added based on the knowledge of those skilled in the art. Embodiments to which is added can also be included in the scope of the embodiments of the present invention.

  The coating apparatus 1 according to the present invention basically assumes that a slurry such as an active material is applied to a sheet base material when an electrode of a laminate-type lithium ion secondary battery is manufactured. The coating apparatus 1 according to the present invention is not limited to such applications.

  In the coating apparatus 1 according to the present invention, the tank 20 is a storage unit for the slurry 5 and also a supply unit for supplying the slurry 5 to the die head 60. Such a tank 20 is preferably configured to receive the supply of the slurry 5 from a main tank (not shown) or the like.

  The tank 20 is connected to the die head 60 by the pipe 10. The pipe 10 is provided with a pump 30 that is a liquid feeding means. By operating the pump 30, the slurry 5 is sent from the tank 20 to the die head 60 side (in the direction of the arrow in the figure).

  The piping 10 in the coating apparatus 1 is branched, the branched piping 10 on one side is connected to the die head 60, and the branched piping 10 on the other side is connected to the tank 20.

  A coating valve 40 is provided in the middle of the branched pipe 10 on one side. A return valve 50 is provided in the middle of the branched pipe 10 on the other side. When the return valve 50 is open, the slurry 5 can be returned to the tank 20 side. Further, when the coating valve 40 is in the open state, the slurry 5 is supplied to the die head 60. The open / close state of each valve is according to the legend in FIG. FIG. 1 shows that the coating valve 40 is in an open state and the return valve 50 is in a closed state.

  In addition, it is preferable to use a motor valve at least for the coating valve 40. The motor valve can accurately change the opening and closing of the valve even during the application of the slurry 5, and realize a complicated coating state by controlling the flow path of the slurry 5 in combination with the operation of the return valve 50. Is possible.

  As the die head 60, for example, a so-called slot die is used. The die head 60 is provided with an inlet 61 to which the slurry 5 is supplied from the pipe 10. The die head 60 is provided with a liquid reservoir called a manifold 63. The slurry 5 supplied from the inflow port 61 is discharged from the coating outlet 65 through the manifold 63. The coating outlet 65 has a slit shape with a constant width.

  The sheet base material 3 is stretched around the back roll 8 in a state where a predetermined tension is applied. Further, the coating apparatus 1 according to the present invention has a conveying means (not shown) such as a rotating roller, and the sheet base material 3 is conveyed by the conveying means in the direction of the arrow in the figure. . As the sheet base material 3 is conveyed, the back roll 8 rotates.

When the coating valve 40 is in the open state, the slurry 5 is coated from the coating outlet 65, and the coating film 7 is formed on the sheet substrate 3. A portion where the coating film 7 is formed is referred to as a coating portion. On the other hand, when the coating valve 40 is in a closed state, the slurry 5 is not applied, and a non-coated portion is formed on the sheet base material 3. Thus, according to the coating apparatus 1 which concerns on this invention, the coating part and the non-coating part can be formed on the sheet base material 3 alternately. Moreover, the coating method by such a coating apparatus 1 is called intermittent coating.

  An extension port 68 is provided from the manifold 63 of the die head 60 toward the upper portion of the die head 60. An extension pipe 69 is attached to the extension port 68. An air damper 80 is provided at the end of the extension pipe 69 that is not on the extension port 68 side. Accordingly, the space in the air damper 80 communicates with the coating outlet 65 through the manifold 63. An electromagnetic valve 70 is provided in the extension pipe 69 between the extension port 68 and the air damper 80.

  FIG. 2 is a perspective view of the die head 60 used in the coating apparatus 1 according to the embodiment of the present invention. FIG. 2A shows an example in which one extension port 68 is provided in the die head 60 and one air damper 80 is attached. FIG. 2B shows an example in which two extension ports 68 are provided in the die head 60 and two air dampers 80 are attached. Thus, the number of extension openings 68 provided in the die head 60 and the number of air dampers 80 can be arbitrarily set.

  FIG. 3 is a diagram for explaining the effect of the electromagnetic valve 70 used in combination with the air damper 80 of the coating apparatus 1 according to the embodiment of the present invention. Air A can be introduced into the damper chamber 82 of the air damper 80 by air introduction means (not shown). The air A introduced into the damper chamber 82 has aeroelasticity. The air A introduced into the damper chamber 82 is deformed by the slurry 5, so that the pressure fluctuation and pulsation of the slurry 5 in the die head 60 can be suppressed. That is, when the slurry 5 is discharged from the coating outlet 65 of the die head 60, if the damper chamber 82 of the air damper 80 and the coating outlet 65 are in communication, fluctuations in the pressure in the head can be suppressed by the action of the air damper. it can.

  In particular, sudden pressure fluctuations at the moment when coating is started from the state where slurry is not coated from the coating outlet 65 of the die head 60 can be suppressed by the function of the air damper 80.

  FIG. 3A shows a case where the electromagnetic valve 70 is in an open state. In this case, the damper chamber 82 is in communication with the coating outlet 65. At this time, the air damper 80 functions as a damper, and the pulsation of the pressure of the slurry 5 in the die head 60 can be suppressed.

  In the coating apparatus 1 according to the present invention, at the moment when the slurry 5 is applied onto the sheet substrate 3 from the coating outlet 65 of the die head 60, the pressure of the slurry 5 is reduced by such a damper function of the air damper 80. I try to suppress pulsation.

  Assuming that the damper chamber 82 of the air damper 80 is in communication with the coating outlet 65 at the moment when the state in which the slurry 5 is applied from the coating outlet 65 of the die head 60 is shifted to the state in which coating is stopped, the damper chamber 82 Due to the negative pressure of the air A inside, the slurry 5 in the coating outlet 65 is pulled back into the die head 60. Therefore, at the moment of transition from the state where the slurry 5 is being applied to the state where the application is stopped, as shown in FIG. 3B, the electromagnetic valve 70 is closed and the damper chamber 82 of the air damper 80 is applied. The outlet 65 is shut off.

  Next, control for realizing intermittent coating by the coating apparatus 1 according to the present invention configured as described above will be described.

  FIG. 4 is a view showing a state of the coating film 7 on the sheet substrate 3 formed by intermittent coating by the coating apparatus 1 according to the embodiment of the present invention, and (a) → (b) in FIG. A state in which the coating film 7 is formed on the sheet substrate 3 by the coating apparatus 1 in the order of (c) → (d) → (e) is shown. FIG. 4 shows a state where the coating film 7 for one section is formed.

  In FIG. 4, a rectangular dotted line indicates a position where the coating outlet 65 of the die head 60 is disposed, and an arrow indicates a direction in which the sheet base 3 is conveyed.

  FIG. 5 is a diagram illustrating the opening / closing timings of the coating valve 40, the electromagnetic valve 70, and the return valve 50 in the coating apparatus 1 according to the embodiment of the present invention. The state of formation of the coating film 7 at the timings (a) to (e) in FIG. 5 corresponds to FIGS. 4 (a) to 4 (e).

  The timing in FIG. 5A indicates the timing immediately before the slurry 5 is applied from the coating outlet 65. At this time, the electromagnetic valve 70 is opened, and the damper chamber 82 and the coating outlet 65 are in communication with each other. Thus, the air damper 80 functions as a damper, and the pressure fluctuation of the slurry 5 in the die head 60 is suppressed. At the timing shown in FIG. 5A, the coating valve 40 is closed and the supply of the slurry 5 to the die head 60 is suspended. At the timing shown in FIG. 5A, the return valve 50 is opened so that the slurry 5 is returned to the tank 20 side.

  At the timing of FIG. 5B, the coating valve 40 is opened and the supply of the slurry 5 to the die head 60 is started. Accordingly, as shown in FIG. 4B, the slurry 5 is applied from the application outlet 65, and the formation of the coating film 7 on the sheet base material 3 is started. 5B, the return valve 50 is closed, and the return of the slurry 5 to the tank 20 is interrupted. At the timing of FIG. 5B, the electromagnetic valve 70 is continuously opened, and the air damper 80 functions as a damper, and the pressure fluctuation of the slurry 5 in the die head 60 is suppressed.

  According to such a coating apparatus 1 according to the present invention, the air damper 80 absorbs fluctuations and pulsations of the pressure of the slurry 5 in the die head 60 due to the operation of the coating valve 40 formed of a motor valve. From this, it becomes easy to control the coating amount of the slurry 5 to be coated, and the desired coating film 7 can be obtained, which can contribute to the improvement of the performance of the lithium ion secondary battery.

  FIG. 5C shows the timing during formation of the coating film 7 on the sheet base material 3. At this time, the open / close states of the coating valve 40, the electromagnetic valve 70, and the return valve 50 are the same as the open / close states of FIG.

  The timing of FIG. 5D shows the timing immediately before the application of the slurry 5 from the coating outlet 65 is interrupted. From the state in which the slurry 5 is being applied from the coating outlet 65 of the die head 60, the damper chamber 82 of the air damper 80 is in communication with the coating outlet 65 at the timing at which coating is interrupted (timing in FIG. 5 (e)). If there is, the slurry 5 in the coating outlet 65 is pulled back into the die head 60 due to the negative pressure of the air A in the damper chamber 82. Therefore, at the timing immediately before the transition from the state where the slurry 5 is being applied to the state where the application is stopped, the electromagnetic valve 70 is closed, and the damper chamber 82 of the air damper 80 is disconnected from the application outlet 65.

At the timing shown in FIG. 5E, the coating valve 40 is closed and the supply of the slurry 5 to the die head 60 is stopped. Along with this, as shown in FIG. 4E, the application of the slurry 5 from the application outlet 65 is interrupted. Thereby, the non-coating part is formed on the sheet base material 3. Here, since the electromagnetic valve 70 is closed and the damper chamber 82 of the air damper 80 is cut off from the coating outlet 65, the slurry 5 in the coating outlet 65 is caused by the negative pressure of the air A in the damper chamber 82. Is not pulled back into the die head 60. Further, at the timing of FIG. 5E, the return valve 50 is opened, and the slurry 5 is returned to the tank 20 side.

  Next, the effect of suppressing the pressure fluctuation of the slurry 5 by the air damper 80 will be described. FIG. 6 is a view for explaining the effect of the air damper 80 of the coating apparatus 1 according to the embodiment of the present invention.

  FIG. 6A shows the pressure fluctuation of the slurry 5 when the air damper 80 is not provided. In this case, it can be seen that there is a pressure fluctuation of the slurry 5 having a long period as indicated by an arrow, along with a pressure fluctuation of the slurry 5 having a short period.

  On the other hand, FIG. 6B shows the pressure fluctuation of the slurry 5 when the air damper 80 is provided. In this case, although the pressure fluctuation of the slurry 5 with a short cycle still exists, it can be seen that the pressure fluctuation of the slurry 5 with a long cycle as shown by the arrow in FIG.

  According to the coating apparatus 1 according to the present invention as described above, since the air damper 80 absorbs fluctuations and pulsations of the slurry 5 in the die head 60 accompanying the operation of the coating valve 40 composed of a motor valve, the die head Control of the coating amount of the slurry 5 to be coated from 60 can be facilitated, the desired coating film 7 can be obtained, and the performance of the lithium ion secondary battery can be improved.

  In the timing chart of FIG. 5, the case where the timing (a) is immediately before the timing (b) and the timing (d) is immediately before the timing (e) is illustrated. However, in the coating apparatus 1 according to the present invention, it is possible to perform control such that the timing (a) is the same as the timing (b) and the timing (d) is the same as the timing (e). Is possible.

  In the timing chart of FIG. 5, the return valve 50 is closed when the coating valve 40 is opened, and the return valve 50 is opened when the coating valve 40 is closed. It is not always necessary to interlock with the coating valve 40 in this way, and the control timing in FIG. 5 is merely an example.

  Next, another embodiment of the present invention will be described. FIG. 7 is a diagram schematically showing a coating apparatus 1 according to another embodiment of the present invention. In the previous embodiment, the air damper 80 is configured to be attached to the extension pipe 69 extending from the die head 60.

  In contrast, in the coating apparatus 1 according to another embodiment of the present invention, the extension pipe 69 is branched from the pipe 10 between the die head 60 and the coating valve 40, and the air damper 80 is connected to the extension pipe 69. I try to install it.

  Even with such a configuration, it is possible to enjoy the same effects as in the previous embodiment, and the following additional effects can also be expected.

The die head 60 is very precise, and when the extension pipe 69 is directly provided on the die head 60 and the air damper 80 is attached, the processing cost is also expensive. However, according to the attachment method of the air damper 80 by the coating apparatus 1 according to another embodiment of the present invention, since the extension pipe 69 is only branched from the pipe 10, it is possible to attach the air damper 80 at a reduced cost. Become.

  As described above, the coating apparatus according to the present invention has a damper chamber communicated with the coating outlet of the head, an air damper that is filled with air in the damper chamber, and an electromagnetic wave disposed between the air damper and the coating outlet. According to such a coating apparatus according to the present invention, since the air damper absorbs fluctuations and pulsations of the slurry pressure in the die head accompanying the operation of the coating valve, Control of the coating amount of the slurry to be coated can be facilitated, a desired coating film can be obtained, and the performance of the lithium ion secondary battery can be improved.

DESCRIPTION OF SYMBOLS 1 ... Coating apparatus 3 ... Sheet base material 5 ... Slurry 7 ... Coating film 8 ... Back roll 10 ... Pipe 20 ... Tank 30 ... Pump 40 ...・ Coating valve (motor valve)
50 ... Return valve 60 ... Die head 61 ... Inlet 63 ... Manifold 65 ... Coating outlet 68 ... Extension port 69 ... Extension pipe 70 ... Solenoid valve 80 ... Air damper 82 ... Damper chamber A ... Air

Claims (3)

A head having a coating outlet for discharging slurry to a sheet substrate conveyed by a roller;
A coating valve for controlling the slurry supplied to the head;
An air damper provided in the head, having a damper chamber communicating with the coating outlet, and filled with air in the damper chamber;
A solenoid valve disposed between the air damper and the coating outlet;
The coating apparatus characterized by having. A head having a coating outlet for discharging slurry to a sheet substrate conveyed by a roller;
A coating valve for controlling the slurry supplied to the head;
An air damper provided between the coating valve and the head, having a damper chamber communicating with the coating outlet, and being filled with air in the damper chamber;
A solenoid valve disposed between the air damper and the coating outlet;
The coating apparatus characterized by having. An electrode manufactured by the coating apparatus according to claim 1.

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