JP2014179251A - Method and device for manufacturing electrode for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing an electrode for a battery excellent in productivity.SOLUTION: A method for manufacturing an electrode for a battery includes: a first coating step in which a first coating liquid containing a first active material is coated on the surface of a current collector S from one side to the other side to form a continued flat active material film 11; and a second coating step in which, while executing the first coating step, on the active material film 11 formed by the first coating step, the coating liquid containing a second active material is coated in a plurality of lines separated from each other to form a plurality of rod-like active material patterns 12.

Description

  The present invention relates to a technique for manufacturing a battery electrode in which an active material layer is formed on the surface of a current collector.

  For example, in order to improve electrical characteristics, particularly charge / discharge characteristics of a chemical battery such as a lithium ion battery, it has been studied to increase the surface area with respect to the volume of the active material layer as a three-dimensional structure. Describes a technique for manufacturing an electrode having an active material layer having a line-and-space structure. The line-and-space structure here refers to a structure composed of a plurality of line-shaped patterns (also referred to as “bar-shaped patterns”) spaced apart from each other.

  In the technique described in Patent Document 1, a uniform coating film is formed by applying a first coating liquid containing a first active material on a current collector by a knife coating method, a doctor blade method, or the like, and drying or After forming a flat active material film on the upper surface of the current collector by curing by baking, the second coating liquid containing the second active material is further separated from each other on the active material film by a nozzle scanning method. Is applied to form a line pattern.

Japanese Patent Laying-Open No. 2011-198596 (for example, FIGS. 3 and 5)

  In the technique described in Patent Document 1 described above, a step of forming a flat active material film and a step of forming a line pattern (corresponding to the “active material portion” of the present invention) are performed independently. In addition, the battery electrode is manufactured by using a production system in which devices for executing each process are combined. For this reason, in the technique for manufacturing the electrode for a battery, there is much room for improvement in productivity.

  This invention is made | formed in view of the said subject, and it aims at providing the manufacturing method and manufacturing apparatus of the battery electrode excellent in productivity.

  In the method for manufacturing a battery electrode according to the present invention, the first coating liquid containing the first active material is applied from one side of the surface of the current collector to the other side to form a continuous flat active material film. While performing the coating process and the first coating process, the coating liquid containing the second active material is coated on the active material film formed by the first coating process in a plurality of lines separated from each other. And a second coating step for forming a rod-shaped active material portion.

  In addition, the battery electrode manufacturing apparatus according to the present invention includes a first nozzle that discharges a first coating liquid containing a first active material, a second nozzle that discharges a second coating liquid containing a second active material, A moving mechanism that moves the current collector relative to the first nozzle and the second nozzle; and a control unit that controls the discharge of the coating liquid from the first nozzle and the second nozzle. The first coating liquid is discharged from the first nozzle on the surface of the current collector to form a continuous flat active material film, while the second coating liquid is discharged from the second nozzle to be separated from each other on the active material film. The plurality of rod-shaped active material portions are formed by coating.

  In the invention configured in this manner, a plurality of rod-shaped active material portions are formed on the active material film while forming an active material film on the surface of the current collector, and the current collector, the active material film, and the plurality of rod-shaped materials are formed. A battery electrode is manufactured in the active material portion. As described above, the active material film forming process and the rod-shaped active material part forming process are partially performed in parallel, so that the productivity of the battery electrode is remarkably improved.

Here, when the plurality of rod-shaped active material portions are formed on the active material film so as to be separated from each other, one of the technical matters to be considered most is the suppression of the collapse of the rod-shaped active material portion, that is, the pattern collapse. In order to suppress pattern collapse, it is important to maintain the shape of the active material film that functions as a base portion that supports the rod-shaped active material portion. For this purpose, it is preferable to use a first coating liquid having a viscosity of 1000 [Pa · s] or more at a shear rate of 1 [s ⁻¹ ]. In addition, it is desirable that the active material film is configured to be harder than each rod-shaped active material portion, and thereby pattern collapse can be effectively suppressed.

  In addition, the second active material constituting the rod-shaped active material part may have the same or substantially the same composition as the first active material. By doing so, the interface between the active material film and the rod-shaped active material part is substantially eliminated, and both function as an active material layer and contribute to pattern strengthening.

  In addition, it is possible to perform the drying process immediately after the formation of the laminate (active material layer) by sequentially drying the laminate in which a plurality of rod-shaped active material portions are formed on the active material film, and productivity Can be further improved.

  Furthermore, you may comprise so that an active material film may be dried before forming a some rod-shaped active material part on an active material film. As described above, by drying only the active material film prior to the formation of the rod-shaped active material portion, the viscosity of the active material film is increased and the hardness is increased before the formation of the rod-shaped active material portion. For this reason, pattern collapse can be more effectively suppressed.

  As described above, according to the present invention, the active material film is formed on the surface of the current collector, and the plurality of rod-shaped active material portions are formed on the active material film. An electrode (= current collector + active material film + a plurality of rod-shaped active material portions) can be manufactured.

It is a figure which shows one Embodiment of the manufacturing apparatus of the electrode for batteries concerning this invention. It is a block diagram which shows the electrical structure of the manufacturing apparatus shown in FIG. It is the elements on larger scale of the manufacturing apparatus shown in FIG. It is a figure which shows other embodiment of the manufacturing apparatus of the battery electrode concerning this invention.

  FIG. 1 is a diagram showing an embodiment of a battery electrode manufacturing apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the manufacturing apparatus shown in FIG. The electrode manufacturing apparatus 1 uses a metal sheet (for example, copper foil or aluminum foil) S wound up in a roll shape as a current collector, and applies an active material to the surface of the sheet S to thereby form an active material layer To form a battery electrode. For the following explanation, XYZ coordinate axes are set as shown in FIG. Here, the XY plane is a horizontal plane, and the Z axis coincides with the vertical axis. The positive direction on the Z-axis is a vertically upward direction.

  The electrode manufacturing apparatus 1 includes a transport unit 2, a first nozzle 3, a second nozzle 4, a main drying unit 5, and a control unit 6 that controls each part of the apparatus. The transport unit 2 holds the sheet S before forming the active material wound in a roll shape, and winds the sheet S after the active material layer is formed, and an unwinding unit 21 that feeds the sheet S at a constant speed. A winding unit 22. The unwinding unit 21 and the winding unit 22 are provided apart from each other by a certain distance in the transport direction D. The unwinding unit 21 is controlled by the control unit 6 to unwind the roll sheet S, while the winding unit 22 is controlled by the control unit 6 to wind the sheet S. The sheet S is conveyed at a constant speed in the arrow direction D while applying a constant tension to the sheet S with the winding unit 22. In addition, the first nozzle 3, the second nozzle 4, and the main drying unit 5 are arranged in this order from the upstream side (the −X direction side) to the downstream side (the + X direction side) in the conveyance direction of the sheet S. Has been.

  FIG. 3 is a partially enlarged view of the manufacturing apparatus shown in FIG. 1, and shows the operation of applying the active material by the first nozzle 3 and the second nozzle 4. The first nozzle 3 is disposed above the surface of the sheet S (+ Z direction) at a position near the unwinding portion 21. A slit-like discharge port 31 having substantially the same width as the width of the active material layer (the length in the Y direction) of the electrode to be manufactured by the electrode manufacturing apparatus 1 is provided at the tip of the first nozzle 3. The first nozzle 3 is connected to a first coating liquid supply unit 7 (FIG. 1).

  The first coating liquid supply unit 7 pumps the first coating liquid containing the first active material to the first nozzle 3 in response to a command from the control unit 6. As a result, the first coating liquid is discharged from the slit-shaped discharge port 31 of the first nozzle 3 and applied to the upper surface of the sheet S moving in the transport direction D at the liquid landing position P1. As a result, the flat active material film 11 having a predetermined width is applied and formed on the surface of the sheet S so as to extend from the (−X) direction side to the (+ X) direction side. In the present embodiment, when the predetermined length is reached in the X direction, the first coating liquid supply unit 7 temporarily stops the supply of the first coating liquid, and as shown in FIG. The active material film 11 having a predetermined length L1 is sequentially formed at regular intervals. Further, from the viewpoint of suppressing pattern collapse, the viscosity of the first coating solution is set to be relatively high. This point will be described in detail later.

  The second nozzle 4 is disposed above the surface of the sheet S (+ Z direction) at a position separated from the first nozzle 3 by a distance L0 (<L1) in the (+ X) direction, and is not illustrated. It is fixed together with the first nozzle 3. Therefore, the second nozzle 4 is maintained in a fixed positional relationship with the first nozzle 3. The second nozzle 4 has a structure in which a large number of discharge ports 41 having an opening area smaller than that of the nozzle 3 from which the first coating liquid is discharged are arranged in the Y direction. The second nozzle 4 is connected to a second coating liquid supply unit 8.

  The second coating liquid supply unit 8 pressure-feeds the second coating liquid containing the second active material to the second nozzle 4 in response to a command from the control unit 6. As a result, the second coating liquid is discharged from each discharge port 41 of the second nozzle 4, and Y is applied to the upper surface of the active material film 11 at the liquid landing position P <b> 2 separated from the liquid landing position P <b> 1 by the distance L <b> 0 in the (+ X) direction. The same number of rod-shaped active material patterns 12 as the discharge ports 41 are formed by being applied in a line shape that is separated from each other in the direction and extends along the X direction. Thus, a laminated body 13 composed of the active material film 11 and the plurality of rod-shaped active material patterns 12 is formed on the upper surface of the sheet S functioning as a current collector.

  As the sheet S is conveyed, the laminated body 13 passes through a position immediately below the main drying unit 5. The drying unit 5 has a drying heat source 51 such as a hot air source or an infrared heater, and the drying heat source 51 dries and removes the solvent contained in the laminate 13 (= active material film 11 + rod-like active material pattern 12). Then, the laminate 13 is solidified on the sheet S. Thereby, the solid active material layer 14 is disposed on the sheet S to form an electrode. The active material layer 14 thus formed on the sheet S is taken up by the winding unit 22 together with the sheet S.

  As described above, in this embodiment, the active material film 11 and the plurality of rod-shaped active material patterns 12 are formed on the surface of the sheet S functioning as a current collector, and the battery electrode is manufactured. This is common with the invention described in Patent Document 1. However, in this embodiment, while forming the active material film 11, a plurality of rod-shaped active material patterns 12 are formed on the active material film 11 with a delay of the distance L 0, so The formation process of the active material pattern 12 is executed partially in parallel. For this reason, the productivity of the battery electrode can be significantly improved as compared with the invention described in Patent Document 1.

  Further, as shown in FIG. 1, the laminate (active material layer) 13 in which a plurality of rod-shaped active material patterns 12 are formed on the active material film 11 is configured to be sequentially dried by the main drying unit 5. A drying process can be performed immediately after manufacture of the laminated body 13, and productivity can further be improved.

In the present embodiment, the active material film 11 is formed of the first coating liquid having a relatively high viscosity, for example, a viscosity of 1000 [Pa · s] or higher at a shear rate of 1 [s ⁻¹ ]. The active material film 11 functions as a base portion that supports a plurality of rod-shaped active material patterns 12, and the active material film 11 is formed by using a coating solution having high viscosity and excellent shape retention as described above. It is possible to firmly support the rod-shaped active material pattern 12. For this reason, it can suppress effectively that the rod-shaped active material pattern 12 collapses. In view of supporting the rod-shaped active material pattern 12 by the active material film 11, the active material film 11 may be configured to be harder than each rod-shaped active material pattern 12. It greatly contributes to suppressing the collapse of the.

Furthermore, in this embodiment, the first coating liquid contains the first active material, and the second coating liquid contains the second active material, but the first active material and the second active material are the same or substantially the same. In this case, the interface between the active material film 11 and the rod-shaped active material pattern 12 is substantially eliminated, and the strength of the both is improved so that the rod-shaped active material pattern 12 collapses. Furthermore, it can suppress effectively. Further, the first active material and the second active material may be selected in view of the functions performed by the active material film 11 and the rod-shaped active material pattern 12. That is, the first active material constituting the active material film 11 may be composed of a material having a relatively large charge capacity, and the second active material constituting the rod-shaped active material pattern 12 is a material with fast input / output. You may comprise. When manufacturing the positive electrode for a battery according to the present embodiment, a known material as a positive electrode active material, for example, a material mainly composed of LiCoO ₂ (LCO), LiNiO ₂ or LiFePO ₄ , LiMnPO ₄ , LiMn ₂ O ₄ , A compound typically represented by LiMeO ₂ (Me = MxMyMz; Me, M is a transition metal, x + y + z = 1), such as LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _0.8 Co _0.15 Al _0.05 O ₂ or the like can be used as the active material. Moreover, when manufacturing the negative electrode for a battery according to the present embodiment, a known material as a negative electrode active material, for example, a material mainly composed of Li ₄ Ti ₅ O ₁₂ (LTO), or C, Si (including a compound thereof) Alternatively, Sn or the like can be used as the active material.

  FIG. 4 is a diagram showing another embodiment of the battery electrode manufacturing apparatus according to the present invention. This embodiment is greatly different from the embodiment shown in FIG. 1 in that a membrane drying unit 9 is additionally provided, and other configurations are the same as those in the first embodiment. Therefore, the same components are denoted by the same reference numerals, and the description of the components is omitted.

  As shown in FIG. 4, the film drying unit 9 includes a drying heat source 91 disposed between the first nozzle 3 and the second nozzle 4, and the rod-shaped active material pattern 12 is formed by the drying heat source 91. Only the active material film 11 before coating and forming is heated, and the solvent in the active material film 11 is removed by drying. Accordingly, the viscosity of the active material film 11 is increased before the formation of the rod-shaped active material pattern 12, and the hardness is also increased. For this reason, collapse of the rod-shaped active material pattern 12 can be effectively suppressed. The main purpose of arranging the film drying unit 9 is to prevent the collapse of the rod-shaped active material pattern 12 due to the increase in the viscosity and hardness of the active material film 11 as described above. It is not essential to be solidified, and it may be configured to be dried to a so-called semi-dry level.

  Thus, in the above-described embodiment, the rod-shaped active material pattern 12 corresponds to an example of the “rod-shaped active material portion” of the present invention. Further, there are a step of forming the active material film 11, a step of forming the rod-shaped active material pattern 12, a step of drying the laminate 13 by the main drying unit 5, and a step of drying only the active material film 11 by the film drying unit 9. These correspond to examples of the “first coating step”, “second coating step”, “main drying step” and “film drying step” of the present invention, respectively. Further, the transport unit 2 corresponds to an example of the “moving mechanism” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, both the first nozzle 3 and the second nozzle 4 are attached to the housing. For this reason, the landing positions P1 and P2 of the coating liquid discharged from each nozzle (that is, the coating start position) are fixed without being changed. Here, the first nozzle 3 and the second nozzle 4 may be provided independently to be movable in the X direction. In this case, by moving the first nozzle 3 in the X direction, the liquid application position P1 of the first coating liquid is also shifted in the X direction, and the application start position of the first coating liquid can be adjusted in the X direction. Similarly to the case of the first nozzle 3, the second nozzle 4 is provided so as to be movable in the X direction, and the liquid application position P2 of the second coating liquid can also be shifted in the X direction. In particular, even when it is desired to change the application start position of each coating liquid depending on the material characteristics of the active material, etc., it is possible to flexibly cope with it and improve the versatility of the electrode manufacturing apparatus 1.

  Moreover, in the said embodiment, the sheet | seat S wound in roll shape is sent out, the active material layer (= active material film | membrane 11 + several rod-shaped active material pattern 12) is formed in the surface, and it winds around another roll again and collect | recovers. The present invention is applied to the so-called roll-to-roll type electrode manufacturing apparatus 1, but the application target of the present invention is not limited to this, and includes an active material film and a plurality of rod-shaped active material portions. The present invention can be applied to all techniques for manufacturing battery electrodes in which an active material layer is formed on the surface of a current collector.

  In the above-described embodiment, the coating liquid is ejected from the nozzles 3 and 4 that are fixedly arranged while the sheet S is moved in the transport direction D by the transport unit 2, but the nozzles 3 and 4 are moved. Thus, the active material film 11 and the rod-shaped active material pattern 12 may be formed by relatively moving the sheet S.

  In the above embodiment, a so-called perforated nozzle provided with a plurality of discharge ports 41 is used as the second nozzle 4, but a so-called multi-nozzle formed by connecting a plurality of single nozzles may be used. Good.

  The present invention can be applied to all techniques for manufacturing battery electrodes in which an active material film is formed on a current collector and a plurality of rod-shaped active material portions are further formed on the active material film. Suitable for manufacturing with excellent productivity.

DESCRIPTION OF SYMBOLS 1 ... Electrode manufacturing apparatus 2 ... Conveyance unit (movement mechanism)
3 ... 1st nozzle 4 ... 2nd nozzle 5 ... Main drying unit (main drying means)
6 ... Control unit 9 ... Membrane drying unit (membrane drying means)
11 ... Active material film 12 ... Bar-shaped active material pattern (bar-shaped active material part)
D: Conveying direction P1: Liquid landing position P2: Liquid landing position S: Sheet (current collector)

Claims (9)

A first coating step of forming a continuous flat active material film by applying a first coating liquid containing a first active material from one side of the surface of the current collector to the other side;
While performing the first coating step, a coating liquid containing the second active material is coated on the active material film formed in the first coating step in a plurality of lines spaced apart from each other, thereby forming a plurality of rod-shaped active materials. And a second coating step for forming a substance part. It is a manufacturing method of the battery electrode according to claim 1,
The said 1st coating liquid is a manufacturing method of the battery electrode which has a viscosity of 1000 [Pa * s] or more in the shear rate of 1 [s ^<-1 >]. It is a manufacturing method of the battery electrode according to claim 1 or 2,
The active material film formed by the first application step is a method of manufacturing a battery electrode that is harder than each rod-shaped active material portion formed by the second application step. It is a manufacturing method of the battery electrode according to claim 1 or 2,
The method for manufacturing a battery electrode, wherein the second active material has the same or substantially the same composition as the first active material. A method for producing a battery electrode according to any one of claims 1 to 4,
A method for producing a battery electrode, further comprising a main drying step of drying the structure in which the plurality of rod-shaped active material portions are formed on the active material film. A method for producing a battery electrode according to any one of claims 1 to 5,
The battery electrode manufacturing method further comprising a film drying step of drying the active material film before forming the plurality of rod-shaped active material portions on the active material film formed by the first application step. A first nozzle for discharging a first coating liquid containing a first active material;
A second nozzle for discharging a second coating liquid containing a second active material;
A moving mechanism for moving the current collector relative to the first nozzle and the second nozzle;
A control unit that controls the discharge of the coating liquid from the first nozzle and the second nozzle,
The controller is configured to apply and form a continuous active material film by discharging the first coating liquid from the first nozzle onto the surface of the current collector that is relatively moved, and from the second nozzle to the second. An apparatus for manufacturing a battery electrode, wherein a plurality of rod-shaped active material portions separated from each other are applied and formed on the active material film by discharging a coating liquid. The battery electrode manufacturing apparatus according to claim 7,
An apparatus for manufacturing a battery electrode, further comprising a main drying means for drying a structure in which the plurality of rod-shaped active material portions are formed on the active material film. The battery electrode manufacturing apparatus according to claim 7 or 8,
A first landing position where the first coating liquid discharged from the first nozzle is deposited on the current collector, and a second landing position where the second coating liquid discharged from the second nozzle is deposited on the active material film. An apparatus for manufacturing a battery electrode, further comprising a film drying means for drying the active material film between two liquid landing positions.

Images