WO2015145806A1

WO2015145806A1 - Apparatus for manufacturing power storage device, and method for manufacturing power storage device

Info

Publication number: WO2015145806A1
Application number: PCT/JP2014/072970
Authority: WO
Inventors: 正興松岡; 栄作二ノ宮; 藤井　武; 高原　洋一; 千恵美窪田
Original assignee: 株式会社日立ハイテクノロジーズ
Priority date: 2014-03-26
Filing date: 2014-09-02
Publication date: 2015-10-01
Also published as: KR20160042088A; KR101773728B1; CN105531855A; JP2015187943A; CN105531855B; JP6121353B2

Abstract

　The present invention improves the manufacturing yield for power storage devices such as lithium-ion cells. In order to overcome the above problem, an electrode sheet manufacturing apparatus has a dispenser, a first slit die coater, and a second slit die coater installed in the stated order along the first direction of travel of a collector foil. The dispenser applies a plurality of first insulation materials in a slurry form onto the surface of the collector foil, the first slit die coater applies a positive electrode material in a slurry form onto the surface of the collector foil, and the second slit die coater applies a second insulation material in a slurry form onto the upper surface of the first insulation materials and the positive electrode material. The first insulation materials are applied so as to be set apart from each other in a second direction orthogonal to the first direction, and the positive electrode material is applied between first insulation films adjacent to each other in the second direction.

Description

Electric storage device manufacturing apparatus and electric storage device manufacturing method

The present invention relates to a manufacturing apparatus and a manufacturing method for an electricity storage device, and can be suitably used for, for example, a step of applying an electrode material for an electricity storage device.

As a background art in this technical field, there is JP-A-2003-054991 (Patent Document 1). This publication includes a positive electrode sheet delivery mechanism, a positive electrode material coating mechanism, a positive electrode forming heating mechanism, an electrolysis and insulating material coating mechanism, an electrolysis and insulator forming heating mechanism, and a negative electrode sheet. Secondary equipped with a state material delivery mechanism, a negative electrode material coating mechanism, a negative electrode formation heating mechanism, an electrolysis / insulation material coating mechanism, an electrolysis / insulator formation heating mechanism, and a winding mechanism A battery manufacturing apparatus is described. The winding mechanism is formed by laminating a positive electrode sheet material to which a positive electrode material and electrolysis and an insulating material are fixed, and a negative electrode sheet material to which a negative electrode material and an electrolysis and insulating material are fixed, to form a predetermined shape. It is a rotating mechanism.

JP 2003-054991 A

In Patent Document 1, a positive or negative electrode material (also referred to as an electrode material or an electrode active material) is provided on both sides of a current collector foil (also referred to as a metal foil, an electrode plate, a base material, a substrate, or a sheet). Applying and applying an insulating material (also called electrolysis or insulating material) that continuously forms a separator on the electrode material improves the production efficiency of the secondary battery and makes the secondary battery manufacturing equipment compact. It is described that it becomes possible.

However, in such a method for manufacturing a secondary battery, when the thickness of the insulating material is, for example, about 5 μm to 40 μm, the insulating material may be cut and the electrode material may be exposed. For example, when an electrode material having a thickness of about 100 μm to 400 μm is applied, the side surfaces of the electrode material are inclined, and the thickness of the electrode material becomes non-uniform, making it impossible to form an electrode material having a desired shape. For these reasons, there is a problem that the production yield of the secondary battery is lowered.

Other issues and novel features will become clear from the description of the present specification and the accompanying drawings.

An apparatus for manufacturing an electricity storage device according to an embodiment includes a plurality of slurry-like first surfaces spaced apart from each other in a second direction orthogonal to the first direction and the surface of the current collector foil on the surface of the current collector foil traveling in the first direction. A first application mechanism that applies one insulating material; and a second application mechanism that applies a slurry-like electrode material to a surface of a current collector foil sandwiched between first insulating materials adjacent in a second direction. Further, a third application mechanism is provided for applying a slurry-like second insulating material on the upper surfaces of the first insulating material and the electrode material.

A method for manufacturing an electricity storage device according to an embodiment includes a plurality of slurry-like first surfaces separated from each other in a second direction orthogonal to the first direction and the surface of the current collector foil on the surface of the current collector foil traveling in the first direction. A step of applying an insulating material, a step of applying a slurry-like electrode material to the surface of a current collector foil sandwiched between first insulating materials adjacent in the second direction, and an upper surface of the first insulating material and the electrode material. And applying a slurry-like second insulating material.

According to one embodiment, the production yield of power storage devices such as lithium ion batteries can be improved.

1 is a schematic diagram of an apparatus for producing an electrode sheet for a lithium ion battery in Embodiment 1. FIG. It is sectional drawing of the electrode sheet of each application | coating process and drying process explaining the manufacturing method of the electrode sheet of the lithium ion battery in Embodiment 1. FIG. (A) is sectional drawing (sectional drawing of A1-A1 of FIG. 1) of the electrode sheet of a 1st insulating material (spacer material) application | coating process. (B) is a cross-sectional view of the electrode sheet in the electrode material application step (cross-sectional view of B1-B1 in FIG. 1). (C) is a cross-sectional view (cross-sectional view of C1-C1 in FIG. 1) of the electrode sheet in the second insulating material (separator material) application step. (D) is a cross-sectional view of the electrode sheet in the drying step (cross-sectional view of D1-D1 in FIG. 1). FIG. 3 is a process diagram summarizing a specific manufacturing process of the lithium ion battery in the first embodiment. 6 is a schematic diagram of a production apparatus for an electrode sheet of a lithium ion battery in Embodiment 2. FIG. It is principal part sectional drawing of the electrode sheet of each application | coating process and drying process explaining the manufacturing method of the electrode sheet of the lithium ion battery in Embodiment 2. FIG. (A) is sectional drawing (sectional drawing of A2-A2 of FIG. 4) of the electrode sheet of an electrode material application | coating process. FIG. 5B is a cross-sectional view of the electrode sheet in the first insulating material (spacer material) application step (cross-sectional view taken along B2-B2 in FIG. 4). (C) is a cross-sectional view of the electrode sheet in the second insulating material (separator material) application step (cross-sectional view of C2-C2 in FIG. 4). (D) is a cross-sectional view of the electrode sheet in the drying step (cross-sectional view of D2-D2 in FIG. 4). 6 is a schematic diagram of a production apparatus for an electrode sheet of a lithium ion battery according to Embodiment 3. FIG. It is principal part sectional drawing of the electrode sheet of each application | coating process and drying process explaining the manufacturing method of the electrode sheet of the lithium ion battery in Embodiment 3. FIG. (A) is sectional drawing (sectional drawing of A3-A3 of FIG. 6) of the electrode sheet of a 1st insulating material (spacer material) application | coating process. FIG. 6B is a cross-sectional view of the electrode sheet in the first electrode material application step (cross-sectional view of B3-B3 in FIG. 6). (C) is a cross-sectional view of the electrode sheet in the second electrode material application step (C3-C3 cross-sectional view of FIG. 6). (D) is a cross-sectional view of the electrode sheet in the second insulating material (separator material) application step (cross-sectional view of D3-D3 in FIG. 6). (E) is a cross-sectional view of the electrode sheet in the drying process (cross-sectional view of E3-E3 in FIG. 6). It is process drawing which put together the specific manufacturing process of the lithium ion battery shown as a comparative example. It is the schematic of the manufacturing apparatus of the electrode sheet | seat of the lithium ion battery shown as a comparative example. It is sectional drawing which illustrates typically the state of application | coating of the slurry-like electrode material by a slit die coater.

In the following embodiments, when referring to the number of elements, etc. (including the number, numerical value, quantity, range, etc.), unless otherwise specified, the principle is clearly limited to a specific number, etc. The number is not limited to the specific number, and may be a specific number or more.

Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

In addition, when referring to “consisting of A”, “consisting of A”, “having A”, and “including A”, other elements are excluded unless specifically indicated that only that element is included. It goes without saying that it is not what you do. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

Further, in the drawings used in the following embodiments, hatching is added even in a plan view to make the drawings easy to see. In all the drawings for explaining the following embodiments, parts having the same function are denoted by the same reference numerals, and repeated explanation thereof is omitted. Hereinafter, embodiments will be described in detail with reference to the drawings.

In the following description, the positive electrode material and the negative electrode material are collectively referred to as “electrode material”, the film made of the positive electrode material after the drying process is called “positive electrode film”, and the film made of the negative electrode material after the drying process is called “negative electrode film”. The positive electrode film and the negative electrode film are collectively referred to as “electrode film”. Moreover, in the following description, the positive electrode material, the negative electrode material, and the insulating material before the drying step are substances having fluidity including a liquid such as a binder solution and an organic solvent. In the following description, the current collector foil on which the positive electrode film is formed is “positive electrode sheet (also referred to as positive electrode plate)”, and the current collector foil on which the negative electrode film is formed is “negative electrode sheet (also referred to as negative electrode plate)”. The positive electrode sheet and the negative electrode sheet are collectively referred to as an “electrode sheet (also referred to as an electrode plate)”. In the following description, “the surface of the current collector foil” refers to only the front surface, not the entire surface including the front surface and the back surface of the current collector foil. In the following description, a direction in which the current collector foil travels is referred to as a “first direction”, and a direction orthogonal to the first direction on the surface of the current collector foil is referred to as a “second direction”.

In this embodiment, a lithium ion battery is exemplified as a secondary battery that is an electricity storage device, and a manufacturing apparatus and a manufacturing method thereof will be described, but the present invention is not limited to this.

The lithium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which lithium ions in the electrolyte bear electric conduction.

For example, a lithium-containing composite oxide is used for the positive electrode, and a carbonaceous material is used for the negative electrode. As the electrolyte, for example, an organic solvent such as ethylene carbonate or a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is used. In a lithium ion battery, lithium ions exit from the positive electrode during charging and enter the negative electrode, and conversely during discharge, lithium ions exit from the negative electrode and enter the positive electrode.

In the lithium ion battery, for example, a positive electrode sheet coated with a positive electrode material on the surface of a current collector foil (eg, Al (aluminum) foil) and a negative electrode material applied on the surface of a current collector foil (eg, Cu (copper) foil). An electrode winding body is provided in which a negative electrode sheet and a separator such as a polymer film that prevents contact between the positive electrode film and the negative electrode film are wound. And in a lithium ion battery, while this electrode winding body is inserted in an armored can, electrolyte solution (the said electrolyte) is inject | poured in the armored can.

That is, in a lithium ion battery, a positive electrode sheet in which a positive electrode material is coated on the surface of a current collector foil and a negative electrode sheet in which a negative electrode material is coated on the surface of a current collector foil are formed in a band shape, and the positive electrode formed in a band shape The sheet and the negative electrode sheet are wound in a cross-sectional spiral shape through a separator so that the positive electrode film on the positive electrode sheet and the negative electrode film on the negative electrode sheet are not in direct contact with each other to form an electrode winding body.

(Comparative example)
First, since it seems that the manufacturing apparatus and manufacturing method of a lithium ion battery according to the present embodiment will become clearer, as a comparative example, a lithium ion battery before application of the present invention, which was examined by the present inventors, was studied. The manufacturing apparatus and manufacturing method will be described below.

FIG. 8 is a process diagram summarizing a specific manufacturing process of a lithium ion battery shown as a comparative example.

As shown in FIG. 8, the manufacturing process of the lithium ion battery includes a positive electrode sheet manufacturing process, a negative electrode sheet manufacturing process, a battery cell assembly process, and a battery module assembly process.

In the positive electrode sheet manufacturing process, first, a slurry-like positive electrode material is applied to the surface of a film-like current collector foil (positive electrode material application), and then the upper and side surfaces of the positive electrode material and the current collector foil to which no positive electrode material is applied A slurry-like insulating material to be a separator is applied to the surface of the substrate (application of separator material). Subsequently, after drying the entire coating film obtained by laminating the slurry-like positive electrode material and the slurry-like insulating material (drying), a laminated film of the positive electrode film made of the positive electrode material and the separator made of the insulating material is formed. The current collector foil is subjected to processing such as compression and cutting (processing) to produce a film-like positive electrode sheet having a positive electrode film and a separator.

On the other hand, in the negative electrode sheet manufacturing process, various materials used as raw materials are different from those in the positive electrode sheet manufacturing process, but the procedure until the negative electrode sheet is manufactured is the same as in the positive electrode sheet manufacturing process. First, after applying a slurry-like negative electrode material on the surface of the film-like current collector foil (negative electrode material application), a separator is formed on the upper surface and side surfaces of the negative electrode material and on the surface of the current collector foil on which the negative electrode material is not applied. A slurry-like insulating material is applied (separator material application). Subsequently, after drying the whole coating film obtained by laminating the slurry-like negative electrode material and the slurry-like insulating material (drying), a laminated film of the negative electrode film made of the negative electrode material and the separator made of the insulating material is formed. The current collector foil is subjected to processing such as compression and cutting (processing) to produce a film-like negative electrode sheet having a negative electrode film and a separator.

Next, in the battery cell assembling step, a positive electrode having a size necessary for the battery cell is cut out from the film-like positive electrode sheet, and a negative electrode having a size necessary for the battery cell is cut out from the film-like negative electrode sheet. Put the negative electrode on top of each other and roll them together (winding). Since the separator is already formed on the positive electrode sheet and the negative electrode sheet, in this winding process, it is not necessary to sandwich the separator between the positive electrode and the negative electrode, and the manufacturing cost of the lithium ion battery is reduced. can do.

Next, a group of positive and negative electrode pairs assembled together is assembled and welded (welding / assembly). Subsequently, the group of welded electrode pairs is placed in a battery can into which an electrolytic solution has been injected (injection), and then the battery can is completely sealed (sealing) to produce a battery cell.

Next, the produced battery cell is repeatedly charged / discharged (charge / discharge), and the performance and reliability of the battery cell are examined (for example, the capacity and voltage of the battery cell, and the current and current during charging or discharging the battery cell (Inspection of voltage etc.) (single cell inspection). Thereby, a battery cell is completed and a battery cell assembly process is complete | finished.

Next, in the battery module assembly process, a battery module is configured by combining a plurality of battery cells in series, and a battery system is configured by connecting a controller for charge / discharge control (module assembly). Subsequently, an inspection regarding performance and reliability of the assembled battery module (for example, inspection of capacity and voltage of the battery module, current and voltage at the time of charging or discharging the battery module, etc.) is performed (module inspection). Thereby, a battery module is completed and a battery module assembly process is complete | finished.

FIG. 9 is a schematic view of an apparatus for manufacturing an electrode sheet of a lithium ion battery shown as a comparative example. In FIG. 9, the manufacturing process of the single side | surface of a positive electrode sheet is illustrated. Although omitted here, the manufacturing process of one side of the negative electrode sheet is the same.

As shown in FIG. 9, the current collector foil PEP is fed from the unwinding roll SL1, and the first roller RL1, the second roller RL2, the third roller RL3, the fourth roller RL4, the fifth roller RL5, and the sixth roller RL6. Is conveyed to the take-up roll SL2. A first slit die coater DC1 is installed facing the third roller RL3, and a second slit die coater DC2 is installed facing the fourth roller RL4.

First, the slurry-like positive electrode material PAS supplied from the first slit die coater DC1 at a position facing the third roller RL3 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The positive electrode material PAS is stored in the tank TA1, and is supplied to the surface of the current collector foil PEP by the metering pump PU1.

Subsequently, a slurry-like insulating material IF supplied from the second slit die coater DC2 at a position facing the fourth roller RL4 is applied. The insulating material IF is stored in the tank TA2, and is supplied to the surface of the current collector foil PEP coated with the positive electrode material PAS by the metering pump PU2. That is, the insulating material IF is applied to the upper surface and side surfaces of the positive electrode material PAS and the surface of the current collector foil PEP to which the positive electrode material PAS is not applied.

Subsequently, by passing through the drying furnace DRY, the entire coating film obtained by laminating the positive electrode material PAS and the insulating material IF formed on the surface of the current collector foil PEP was dried, and the coating film was formed on the surface. The current collector foil PEP is wound around the winding roll SL2.

FIG. 10 is a cross-sectional view schematically illustrating the state of application of the slurry-like positive electrode material PAS by the first slit die coater DC1. Although omitted here, the state of application of the slurry-like insulating material IF by the second slit die coater DC2 is also the same.

As shown in FIG. 10, the slurry-like positive electrode material PAS is supplied to the manifold D2 of the die D1 from the tank in which the slurry-like cathode material PAS is stored by a metering pump. In the manifold D2, after the pressure distribution of the slurry-like positive electrode material PAS becomes uniform, the slurry-like positive electrode material PAS is supplied to and discharged from the slit portion D3 provided in the die D1. The discharged slurry-like positive electrode material PAS forms an electrode material reservoir D4 called a bead between the base D1 and the current collector foil PEP that travels relative to the base D1 while maintaining the first distance h1. In the state, the slurry-like positive electrode material PAS is pulled out as the current collector foil PEP travels to form a coating film made of the positive electrode material PAS.

Here, by supplying the same amount of positive electrode material PAS as the amount of positive electrode material PAS consumed by the formation of the coating film from the slit portion D3, the coating film is continuously formed. In order to stably apply the organic solvent-based positive electrode material PAS having a high evaporation rate, it is important to stabilize the formation of the meniscus (bending liquid surface) D5 on the downstream side of the electrode material reservoir D4. Therefore, the pressure for supplying the positive electrode material PAS to the manifold D2 is (pressure loss of the slit portion D3 + pressure loss of the downstream lip portion D6 of the base D1 + pressure of the downstream meniscus D5).

The inventors of the present invention are studying to increase the capacity and miniaturization of lithium ion batteries, and as one means for that, are studying a thinner separator and a thicker electrode film (positive electrode film and negative electrode film). .

However, in order to form a thin separator, it is necessary to reduce the first distance h1 between the base D1 of the second slit die coater DC2 and the current collector foil PEP. The material IF cannot be uniformly applied, and the separator is cut off. Further, even if the insulating material IF can be uniformly applied to the upper surface of the electrode material, the insulating material IF can be uniformly applied to the side surfaces of the electrode material and the surface of the current collector foil PEP to which the electrode material is not applied. Can not. Furthermore, in order to form a thick electrode film, the electrode material must be applied thickly on the surface of the current collector foil PEP. However, when the electrode material is applied thickly, the side surface of the electrode material is inclined (current collector foil PEP). In addition, a depression is formed on the upper surface of the electrode material, and the shape of the electrode material is not stable. For this reason, when trying to reduce the thickness of the separator and the electrode film, there is a problem that the production yield of the lithium ion battery decreases.

(Embodiment 1)
≪Method of manufacturing electrode sheet for lithium ion battery≫
A method for manufacturing the electrode sheet of the lithium ion battery in the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram of an apparatus for manufacturing an electrode sheet for a lithium ion battery according to the first embodiment. FIG. 2 is a cross-sectional view of the electrode sheet in each coating step and drying step for explaining the method for producing the electrode sheet of the lithium ion battery in the first embodiment. 2A is a cross-sectional view of the electrode sheet in the first insulating material (spacer material) application step (cross-sectional view of A1-A1 in FIG. 1), and FIG. 2B is a cross-sectional view of the electrode sheet in the electrode material application step. (Cross-sectional view of B1-B1 in FIG. 1) and FIG. 2C are cross-sectional views (cross-sectional view of C1-C1 in FIG. 1) of the electrode sheet in the second insulating material (separator material) application step. Further, FIG. 2D is a cross-sectional view of the electrode sheet in the drying process (cross-sectional view of D1-D1 in FIG. 1).

Embodiment 1 exemplifies a method of manufacturing a positive electrode film formed in two rows on the surface of the current collector foil along the first direction in which the current collector foil travels. Moreover, in this Embodiment 1, although the manufacturing method of the single side | surface of a positive electrode sheet is illustrated, the manufacturing method of the single side | surface of a negative electrode sheet is also the same.

As shown in FIG. 1, in the electrode sheet manufacturing apparatus M1, the current collector foil PEP is fed from the unwinding roll SL1, and the first roller RL1, the second roller RL2, the third roller RL3, the fourth roller RL4, The paper is conveyed to the take-up roll SL2 by the 5-roller RL5, the sixth roller RL6, and the seventh roller RL7. A dispenser DP is installed facing the third roller RL3, a first slit die coater DC1 is installed facing the fourth roller RL4, and a second slit die coater DC2 is installed facing the fifth roller RL5.

1. First coating process (first insulating material (spacer material) coating process)
First, the slurry-like first insulating material IF1 supplied from the dispenser DP at a position facing the third roller RL3 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The first insulating material IF1 is stored in the tank TA1, and is supplied to the surface of the current collector foil PEP by the metering pump PU1.

As shown in FIG. 2A, the plurality of first insulating materials IF1 are arranged on the surface of the current collector foil PEP traveling in the first direction in the second direction orthogonal to the first direction and the surface of the current collector foil PEP. They are applied separately from each other. That is, the plurality of first insulating materials IF1 collects current in such a manner that a region in which the positive electrode material PAS is applied to the surface of the current collector foil PEP traveling in the first direction in the second application step is sandwiched in the second direction. It is applied to the surface of the foil PEP. In other words, the plurality of first insulating materials IF1 regulate the width in the second direction of the region of the positive electrode material PAS applied to the surface of the current collector foil PEP traveling in the first direction in the subsequent second application step. To be applied. In the first embodiment, in order to form two rows of positive electrode films along the first direction on the surface of the current collector foil PEP, the plurality of first insulating materials IF1 are separated from each other in the second direction, and the current collector foil Three rows are applied to the surface of the PEP along the first direction.

The thickness of the first insulating material IF1 is substantially the same as the thickness of the positive electrode material PAS applied to the surface of the current collector foil PEP in the subsequent second application step. In addition, since the region to which the first insulating material IF1 is applied is a region that is cut after the positive electrode sheet is completed, the width in the second direction of the first insulating material IF1 is set to be small in order to reduce the material cost. The For example, considering the width required for cutting, the width in the second direction of the first insulating material IF1 is about 5 mm to 15 mm.

2. Second application process (electrode material application process)
Next, the slurry-like positive electrode material PAS supplied from the first slit die coater DC1 at a position facing the fourth roller RL4 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The positive electrode material PAS is stored in the tank TA2, and is supplied to the surface of the current collector foil PEP by the metering pump PU2.

As shown in FIG. 2B, the plurality of positive electrode materials PAS are applied to the surface of the current collector foil PEP traveling in the first direction and to the surface of the current collector foil PEP in the previous first application step. 1 It apply | coats to the area | region pinched | interposed into insulating material IF1. In the first embodiment, in order to form two rows of positive electrode films along the first direction on the surface of the current collector foil PEP, the plurality of positive electrode materials PAS are separated by the first insulating material IF1 in the second direction. Two rows are applied along the first direction on the surface of the current collector foil PEP so as to be separated from each other.

The thickness of the positive electrode material PAS is substantially the same as the thickness of the first insulating material IF1. Although it is desirable that the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 are the same, in order to prevent the positive electrode material PAS from being applied to the upper surface of the first insulating material IF1, the upper surface of the positive electrode material PAS is 1 The positive electrode material PAS is applied so as to be lower by about 0 μm to 10 μm than the upper surface of the insulating material IF1. The thickness of the positive electrode material PAS can be adjusted, for example, by adjusting the height of the base D1 of the first slit die coater DC1 (see FIG. 10) and the feed amount of the positive electrode material PAS.

When the first insulating material IF1 is not applied, when the positive electrode material PAS is applied thickly, the side surface of the positive electrode material PAS is inclined, and a depression is formed on the upper surface of the positive electrode material PAS, so that the shape of the positive electrode material PAS is not stable. There is a problem. However, in the first embodiment, since the region where the positive electrode material PAS is applied is defined in advance by the first insulating material IF1, the positive electrode material can be applied even if the positive electrode material PAS is applied thickly (eg, about 100 μm to 400 μm). Since the side surface of the PAS is not inclined, the shape of the positive electrode material PAS is stabilized.

3. Third coating process (second insulating material (separator material) coating process)
Next, a slurry-like second insulating material IF2 supplied from the second slit die coater DC2 at a position facing the fifth roller RL5 is applied. The second insulating material IF2 is stored in the tank TA3, and is supplied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS by the metering pump PU3.

As shown in FIG. 2 (c), the second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS along the first direction in which the current collector foil PEP travels. The thickness of the second insulating material IF2 is, for example, about 5 μm to 40 μm. The thickness of the second insulating material IF2 can be adjusted, for example, by adjusting the height of the base D1 of the second slit die coater DC2 (see FIG. 10) and feeding the second insulating material IF2.

In order to apply the second insulating material IF2 thinly, as shown in FIG. 10, it is necessary to reduce the first distance h1 between the base D1 of the second slit die coater DC2 and the current collector foil PEP. However, the second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS, which are substantially flat surfaces, for example, the side surfaces of the first insulating material IF1 and the positive electrode material PAS, and the first insulating material IF1 and It is not applied to the surface of the current collector foil PEP to which the positive electrode material PAS is not applied. Accordingly, even if the first distance h1 between the die D1 of the second slit die coater DC2 and the current collector foil PEP is small, the second insulating material IF2 can be uniformly applied, so the film of the second insulating material IF2 Cutting can be prevented.

4). Next, by passing through a drying furnace (drying mechanism) DRY, the positive electrode material PAS and the first insulating material IF1 applied to the surface of the current collector foil PEP, and the second insulating material IF2 applied to the upper surface thereof The entire coated film is dried, and the current collector foil PEP on which the positive electrode film and the separator are formed is wound on the winding roll SL2.

As shown in FIG. 2D, the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 were substantially the same before drying, but after drying, the thickness of the spacer SP made of the first insulating material IF1. The thickness is smaller than the thickness of the positive electrode film PE made of the positive electrode material PAS. This is due to the difference between the amount of solid matter (eg, positive electrode active material and conductive additive) contained in the positive electrode material PAS and the amount of solid matter contained in the first insulating material IF1. That is, the amount of the solid matter contained in the positive electrode material PAS is relatively large, and the amount of the solid matter contained in the first insulating material IF1 is controlled to be relatively small. It is made thinner than the thickness of the positive electrode film PE.

This is due to the following reasons. That is, in order to improve the adhesion between the current collector foil PEP and the positive electrode film PE and to bind the solids in the positive electrode material PAS to each other, the positive electrode film PE and the spacer SP were applied to the upper surfaces of these after drying. Before the laminated film with the separator SE made of the second insulating material IF2 is cut, the laminated film is compressed (roll press). During the compression, it is important to apply a load to the positive electrode film PE. Therefore, if the spacer SP is thicker than the positive electrode film PE, the load is not applied to the positive electrode film PE. Therefore, it is necessary to make the thickness of the spacer SP thinner than the thickness of the positive electrode film PE.

In the first embodiment, the method for manufacturing the positive electrode film PE formed in two rows on the surface of the current collector foil PEP along the first direction in which the current collector foil PEP travels is exemplified, but the present invention is not limited thereto. It is not something. For example, the positive electrode film PE may be one row or three or more rows, and the same effect can be obtained.

≪Specific manufacturing process of lithium-ion battery≫
A specific manufacturing process of the lithium ion battery according to the first embodiment will be described with reference to FIG. FIG. 3 is a process diagram summarizing a specific manufacturing process of the lithium ion battery in the first embodiment.

As shown in FIG. 3, the manufacturing process of the lithium ion battery is the same as the manufacturing process of the lithium ion battery shown in FIG. 8, the positive electrode sheet manufacturing process, the negative electrode sheet manufacturing process, the battery cell assembling process, and the battery. Module assembly process.

In the positive electrode sheet manufacturing process, first, a plurality of slurry-like first insulating materials serving as spacers are separated from each other in a second direction orthogonal to the first direction in which the current collector foil runs on the surface of the film-like current collector foil. And apply (spacer material application). The first insulating material is produced by mixing and preparing various materials as raw materials.

Subsequently, on the surface of the film-like current collector foil, a slurry-like positive electrode material is applied between the first insulating materials applied separately in the second direction (positive electrode material application). The positive electrode material is produced by mixing and preparing various materials as raw materials.

Subsequently, a slurry-like second insulating material serving as a separator is applied to the top surfaces of the first insulating material and the positive electrode material formed on the surface of the film-like current collector foil (separator material application). The second insulating material is produced by mixing and preparing various materials as raw materials.

Subsequently, after drying the entire coating film obtained by laminating the positive electrode material and the first insulating material applied to the surface of the film-shaped current collector foil and the second insulating material applied to the upper surface thereof (drying), Processing such as compression and cutting is performed on the current collector foil on which the coating film is formed (processing). Thereby, the film-form current collector foil has a film-like shape in which the positive electrode film made of the positive electrode material and the spacer made of the first insulating material and the separator made of the second insulating material formed on the upper surface thereof are laminated. The positive electrode sheet is manufactured. When cutting the current collector foil on which the coating film is formed, the region where the spacer made of the first insulating material is formed is cut.

On the other hand, in the negative electrode sheet manufacturing process, various materials used as raw materials are different from those in the positive electrode sheet manufacturing process, but the procedure until the negative electrode sheet is manufactured is the same as in the positive electrode sheet manufacturing process. First, a plurality of slurry-like first insulating materials serving as spacers are applied to the surface of a film-like current collecting foil in a second direction perpendicular to the first direction in which the current collecting foil runs (spacer). Material application). The first insulating material is produced by mixing and preparing various materials as raw materials.

Subsequently, a slurry-like negative electrode material is applied between the first insulating materials applied in the second direction so as to be separated from each other on the surface of the film-like current collecting foil (negative electrode material application). The negative electrode material is produced by mixing and preparing various materials as raw materials.

Subsequently, a slurry-like second insulating material serving as a separator is applied to the upper surfaces of the first insulating material and the negative electrode material formed on the surface of the film-like current collecting foil (separator material application). The second insulating material is produced by mixing and preparing various materials as raw materials.

Subsequently, after drying the entire coating film obtained by laminating the negative electrode material and the first insulating material applied to the surface of the film-like current collector foil and the second insulating material applied to the upper surface thereof (drying), Processing such as compression and cutting is performed on the current collector foil on which the coating film is formed (processing). As a result, a film-like current collecting foil is laminated on the surface of the negative electrode film made of the negative electrode material and the spacer made of the first insulating material and the separator made of the second insulating material formed on the upper surface thereof. The negative electrode sheet is manufactured. When cutting the current collector foil on which the coating film is formed, the region where the spacer made of the first insulating material is formed is cut.

Next, in the battery cell assembling step, a positive electrode having a size necessary for the battery cell is cut out from the film-like positive electrode sheet, and a negative electrode having a size necessary for the battery cell is cut out from the film-like negative electrode sheet. Put the negative electrode on top of each other and roll them together (winding). Since the separator is already formed on the positive electrode sheet and the negative electrode sheet, in this winding step, it is not necessary to sandwich the separator between the positive electrode and the negative electrode, and the manufacturing cost can be reduced. .

Thereafter, the battery cell is completed and the battery module is completed in the same manner as the method of manufacturing the lithium ion battery of the comparative example described with reference to FIG.

≪Each material of lithium ion battery≫
As the positive electrode active material used in Embodiment 1, for example, a lithium-containing composite oxide having a spinel structure containing lithium cobaltate or Mn (manganese) can be used. As the positive electrode active material, a composite oxide containing Ni (nickel), Co (cobalt), and Mn (manganese), or an olivine type compound represented by olivine type iron phosphate can be used. However, the material used for the positive electrode active material is not limited to these.

Since a lithium-containing composite oxide having a spinel structure containing Mn (manganese) is excellent in thermal stability, a lithium ion battery with high safety can be formed by forming a positive electrode sheet containing this. . Further, as the positive electrode active material, only a lithium-containing composite oxide having a spinel structure containing Mn (manganese) may be used, but other positive electrode active materials may be used in combination. Examples of such other positive electrode active materials include olivine type represented by Li _{1 + x} MO ₂ (−0.1 <x <0.1, M: Co, Ni, Mn, Al, Mg, Zr, Ti, etc.), for example. Compound etc. are mentioned. Further, specific examples of the lithium-containing transition metal oxide having a layer structure include LiCoO ₂ or LiNi _1-x Co _xy Al _y O ₂ (0.1 ≦ x ≦ 0.3, 0.01 ≦ y ≦ 0). .2) can be used. Further, the lithium-containing transition metal oxide having a layered structure includes an oxide containing at least Ni (nickel), Co (cobalt), and Mn (manganese) (LiMn _1/3 Ni _1/3 Co _1/3 O ₂ , LiMn _5/12 Ni _5/12 Co _1/6 O ₂ , LiNi _3/5 Mn _1/5 Co _1/5 O _2, etc.) can be used.

As the negative electrode active material used in Embodiment 1, for example, a graphite material such as natural graphite (flaky graphite), artificial graphite, or expanded graphite can be used. Further, as the negative electrode active material, an easily graphitizable carbonaceous material such as coke obtained by firing pitch can be used. Further, a non-graphitizable carbonaceous material such as amorphous carbon obtained by low-temperature firing of furfuryl alcohol resin (PFA), polyparaphenylene (PPP), phenol resin, or the like may be used as the negative electrode active material. Good. In addition to the carbon material, Li (lithium) or a lithium-containing compound can also be used as the negative electrode active material.

Examples of the lithium-containing compound include a lithium alloy such as Li—Al or an alloy containing an element that can be alloyed with Li (lithium) and Si (silicon) or Sn (tin). Furthermore, an oxide-based material such as Sn oxide or Si oxide can also be used.

The conductive auxiliary agent used in the first embodiment is used as an electronic conductive auxiliary agent to be contained in the positive electrode film. For example, a carbon material such as carbon black, acetylene black, ketjen black, graphite, carbon fiber, or carbon nanotube is preferable. . Among the above carbon materials, acetylene black or ketjen black is particularly preferable from the viewpoint of the amount of addition and conductivity and the manufacturability of the coating positive electrode mixture slurry. The conductive auxiliary agent can be contained in the negative electrode film, and may be preferable.

The binder used in the first embodiment preferably also contains a binder for binding the active material and the conductive additive. As the binder, for example, a polyvinylidene fluoride-based polymer (a polymer of a fluorine-containing monomer group containing 80% by mass or more of vinylidene fluoride as a main component monomer) or a rubber-based polymer is preferably used. Two or more of the above polymers may be used in combination. The binder is preferably provided in the form of a solution dissolved in a solvent.

Examples of the fluorine-containing monomer group for synthesizing the polyvinylidene fluoride-based polymer include vinylidene fluoride, or a mixture of vinylidene fluoride and another monomer, and a monomer mixture containing 80% by mass or more of vinylidene fluoride. Can be mentioned. Examples of other monomers include vinyl fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, and fluoroalkyl vinyl ether.

Examples of the rubber-based polymer include styrene butadiene rubber (SBR), ethylene propylene diene rubber, and fluorine rubber.

Content of the binder in an electrode film is 0.1 mass% or more on the basis of the electrode film after drying, More preferably, it is 0.3 mass% or more, 10 mass% or less, Furthermore, it is 5 mass% or less. More desirable. If the binder content is too small, not only is the solidification in the drying process insufficient, but the mechanical strength of the electrode film after drying is insufficient, and the electrode film may peel from the current collector foil. Moreover, when there is too much content of a binder, there exists a possibility that the amount of active materials in an electrode film may reduce and battery capacity may become low.

As the insulating material used in Embodiment 1, an inorganic oxide such as Al ₂ O ₃ (alumina) or SiO ₂ (silica) can be used. In addition, a slurry in which fine particles of polypropylene or polyethylene are confused may be used, and by using this, shutdown property can be provided. In order to bind the inorganic oxide particles used for the insulating material, a resin is used as a binder. The binder used for the electrode film is preferably used as the binder.

The current collector foil used in the first embodiment is not limited to a sheet-like foil. As the substrate, for example, pure metal or alloy conductive material such as Al (aluminum), Cu (copper), stainless steel or Ti (titanium) is used, and the shape thereof is a net, punched metal, foam metal or plate. A foil processed into a shape is used. As the thickness of the current collector foil, for example, 5 μm to 30 μm, more preferably 8 μm to 16 μm is selected. Further, the thickness of the electrode film formed on one surface (surface) of the current collector foil is a thickness after drying, for example, about 50 μm to 400 μm.

In addition, the lithium ion battery in this Embodiment 1 can be manufactured similarly to the conventional lithium ion battery except including the positive electrode and negative electrode which are manufactured by the method mentioned above. There is no particular limitation on the structure or size of the battery container or the structure of the electrode body having the positive and negative electrodes as main components.

As described above, according to the first embodiment, even when the electrode material to be an electrode film is applied thickly on the surface of the current collector foil PEP, the side surface of the electrode material is not inclined and the shape of the electrode material is stabilized. Therefore, the electrode material can be applied thickly on the surface of the current collector foil PEP. Further, even if the electrode material is applied thickly and the second insulating material IF2 to be the separator SE is applied thinly, the second insulating material IF2 is not cut off, so the second insulating material IF2 is applied thinly and uniformly. be able to. Thereby, it is possible to reduce the thickness of the separator SE and the electrode film without reducing the production yield of the lithium ion battery.

(Embodiment 2)
The difference from the first embodiment described above is the process sequence of the step of applying the first insulating material to be the spacer and the step of applying the electrode material to be the electrode film. That is, in Embodiment 1 described above, the first insulating material IF1 is applied to the surface of the current collector foil PEP, and then the positive electrode material PAS is applied to the surface of the current collector foil PEP. After the material PAS is applied to the surface of the current collector foil PEP, the first insulating material IF1 is applied to the surface of the current collector foil PEP.

≪Method of manufacturing electrode sheet for lithium ion battery≫
A method for manufacturing the electrode sheet of the lithium ion battery in the second embodiment will be described with reference to FIGS. FIG. 4 is a schematic diagram of an apparatus for manufacturing an electrode sheet for a lithium ion battery according to the second embodiment. FIG. 5 is a cross-sectional view of the electrode sheet in each coating step and drying step for explaining the method of manufacturing the electrode sheet of the lithium ion battery in the second embodiment. 5A is a cross-sectional view of the electrode sheet in the electrode material application step (cross-sectional view of A2-A2 in FIG. 4), and FIG. 5B is a cross-sectional view of the electrode sheet in the first insulating material (spacer material) application step. (Cross-sectional view of B2-B2 in FIG. 4) and FIG. 5 (c) are cross-sectional views (cross-sectional view of C2-C2 in FIG. 4) of the electrode sheet in the second insulating material (separator material) application step. Further, FIG. 5D is a cross-sectional view of the electrode sheet in the drying process (cross-sectional view of D2-D2 in FIG. 4).

Embodiment 2 exemplifies a method for manufacturing a positive electrode film formed in a line on the surface of the current collector foil along the first direction in which the current collector foil travels. In the second embodiment, a method for producing one side of the positive electrode sheet is illustrated, but the method for producing one side of the negative electrode sheet is also the same.

As shown in FIG. 4, in the electrode sheet manufacturing apparatus M2, the current collector foil PEP is fed from the unwinding roll SL1, and the first roller RL1, the second roller RL2, the third roller RL3, the fourth roller RL4, The paper is conveyed to the take-up roll SL2 by the 5-roller RL5, the sixth roller RL6, and the seventh roller RL7. A first slit die coater DC1 is installed facing the third roller RL3, a dispenser DP is installed facing the fourth roller RL4, and a second slit die coater DC2 is installed facing the fifth roller RL5.

1. First application process (electrode material application process)
First, the slurry-like positive electrode material PAS supplied from the first slit die coater DC1 at a position facing the third roller RL3 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The positive electrode material PAS is stored in the tank TA1, and is supplied to the surface of the current collector foil PEP by the metering pump PU1.

As shown in FIG. 5A, the positive electrode material PAS is applied to the surface of the current collector foil PEP running in the first direction.

2. Second coating process (first insulating material (spacer material) coating process)
Next, the slurry-like first insulating material IF1 supplied from the dispenser DP at a position facing the fourth roller RL4 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The first insulating material IF1 is stored in the tank TA2, and is supplied to the surface of the current collector foil PEP by the metering pump PU2.

As shown in FIG.5 (b), several 1st insulating material IF1 was apply | coated to the surface of current collection foil PEP in the 1st application | coating process on the surface of current collection foil PEP which drive | works in a 1st direction. The positive electrode material PAS is applied so as to be sandwiched between a first direction and a second direction orthogonal to the surface of the current collector foil PEP. In other words, the first insulating material IF1 is applied to the surface of the current collector foil PEP outside the positive electrode material PAS in the second direction in contact with both side surfaces of the positive electrode material PAS in the second direction.

The thickness of the first insulating material IF1 is substantially the same as the thickness of the positive electrode material PAS. As in the first embodiment, the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 are desirably the same, but the positive electrode material PAS is applied to the upper surface of the first insulating material IF1. In order to prevent this, the first insulating material IF1 is applied such that the upper surface of the positive electrode material PAS is lower by about 0 μm to 10 μm than the upper surface of the first insulating material IF1. Further, the region to which the first insulating material IF1 is applied is a region that is cut after the positive electrode sheet is completed.

The dispenser DP has the advantage that the position adjustment is easier than the first slit die coater DC1 as a feature of the mechanism. For example, if the positive electrode material PAS is applied after the first insulating material IF1 is applied as in the first embodiment, the position of the first slit die coater DC1 is shifted, and the positive electrode material PAS is formed on the upper surface of the first insulating material IF1. May be applied. However, in the second embodiment, after applying the positive electrode material PAS, the first insulating material IF1 and the positive electrode material are applied using the dispenser DP whose alignment is easy to adjust. Misalignment with PAS can be eliminated. However, when the thickness of the positive electrode material PAS is increased, the side surface of the positive electrode material PAS is inclined, so that the positive electrode material PAS cannot be formed thick as in the case of the first embodiment described above.

3. Third coating process (second insulating material (separator material) coating process)
Next, in the same manner as the third application process (second insulating material (separator material) application process) of the first embodiment, the slurry state supplied from the second slit die coater DC2 at a position facing the fifth roller RL5. The second insulating material IF2 is applied. The second insulating material IF2 is stored in the tank TA3, and is supplied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS by the metering pump PU3.

As shown in FIG. 5C, the second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS along the first direction in which the current collector foil PEP travels. The thickness of the second insulating material IF2 is, for example, about 5 μm to 40 μm. The thickness of the second insulating material IF2 can be adjusted, for example, by adjusting the height of the base D1 of the second slit die coater DC2 (see FIG. 10) and feeding the second insulating material IF2.

Similar to the first embodiment, the second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS, which are substantially flat surfaces, for example, the side surfaces of the first insulating material IF1 and the positive electrode material PAS, In addition, the first insulating material IF1 and the positive electrode material PAS are not applied to the surface of the current collector foil PEP to which the first insulating material IF1 and the positive electrode material PAS are not applied. Therefore, since the second insulating material IF2 can be uniformly applied, it is possible to prevent the second insulating material IF2 from being cut.

4). Next, similarly to the drying process of the first embodiment, the positive electrode material PAS and the first insulating material IF1 applied to the surface of the current collector foil PEP by passing through the drying furnace (drying mechanism) DRY The entire coating film obtained by laminating the second insulating material IF2 applied to these upper surfaces is dried, and the current collector foil PEP having the positive electrode film and the separator formed on the surface is wound on the winding roll SL2.

As shown in FIG. 5D, the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 were substantially the same before drying, but after drying, the amount of solids contained in the positive electrode material PAS The thickness of the spacer SP made of the first insulating material IF1 is thinner than the thickness of the positive electrode film PE made of the positive electrode material PAS because of the difference between the amount of the solid matter contained in the first insulating material IF1.

In the second embodiment, the method for manufacturing the positive electrode film PE formed in one row on the surface of the current collector foil PEP along the first direction in which the current collector foil PEP travels is exemplified, but the present invention is not limited to this. It is not something. For example, the positive electrode film PE may have two or more rows, and the same effect can be obtained.

As described above, according to the second embodiment, the misalignment between the first insulating material IF1 and the electrode material is eliminated. Further, even if the second insulating material IF2 to be the separator SE is thinly applied, the film of the second insulating material IF2 does not break, so that the second insulating material IF2 can be thinly and uniformly applied. Thereby, the separator SE can be made thinner without reducing the production yield of the lithium ion battery.

(Embodiment 3)
The difference from the first embodiment described above is the number of steps for applying the electrode material. That is, in Embodiment 1 described above, the positive electrode material PAS is applied to the surface of the current collector foil PEP by a single application process, but in the present Embodiment 3, the positive electrode material PAS is collected by two application processes. It is applied to the surface of the electric foil PEP.

≪Method of manufacturing electrode sheet for lithium ion battery≫
A method for manufacturing the electrode sheet of the lithium ion battery in the third embodiment will be described with reference to FIGS. FIG. 6 is a schematic diagram of an apparatus for manufacturing an electrode sheet for a lithium ion battery according to the third embodiment. FIG. 7 is a cross-sectional view of the electrode sheet in each coating step and drying step for explaining the method of manufacturing the electrode sheet of the lithium ion battery in the third embodiment. 7A is a cross-sectional view of the electrode sheet in the first insulating material (spacer material) application step (cross-sectional view of A3-A3 in FIG. 6), and FIG. 7B is an electrode sheet in the first electrode material application step. Cross-sectional views (cross-sectional view of B3-B3 in FIG. 6) and FIG. 7 (c) are cross-sectional views (cross-sectional view of C3-C3 in FIG. 6) of the electrode sheet in the second electrode material application step. Further, FIG. 7D is a cross-sectional view of the electrode sheet in the second insulating material (separator material) application step (cross-sectional view of D3-D3 in FIG. 6), and FIG. 7E is a cross-sectional view of the electrode sheet in the drying step. FIG. 7 is a sectional view taken along line E3-E3 in FIG.

Embodiment 3 exemplifies a method for manufacturing a positive electrode film formed in two rows on the surface of the current collector foil along the first direction in which the current collector foil travels. Moreover, in this Embodiment 3, although the manufacturing method of the single side | surface of a positive electrode sheet is illustrated, the manufacturing method of the single side | surface of a negative electrode sheet is also the same.

As shown in FIG. 6, in the electrode sheet manufacturing apparatus M3, the current collector foil PEP is fed from the unwinding roll SL1, and the first roller RL1, the second roller RL2, the third roller RL3, the fourth roller RL4, The paper is conveyed to the take-up roll SL2 by the 5-roller RL5, the sixth roller RL6, the seventh roller RL7, and the eighth roller RL8. A dispenser DP is installed facing the third roller RL3, a first slit die coater DC1 is installed facing the fourth roller RL4, a second slit die coater DC2 is installed facing the fifth roller RL5, and the sixth A third slit die coater DC3 is installed facing the roller RL6.

1. First coating process (first insulating material (spacer material) coating process)
First, the first insulating material IF1 is applied to the surface of the current collector foil PEP in the same manner as the application process (first insulating material (separator material) applying process) of the first embodiment described above.

As shown to Fig.7 (a), several 1st insulating material IF1 is in the 2nd direction orthogonal to the surface of the current collection foil PEP which runs in the 1st direction at the surface of the 1st direction and the current collection foil PEP. They are applied separately from each other. That is, the plurality of first insulating materials IF1 sandwich the region in which the positive electrode material PAS is applied on the surface of the current collector foil PEP traveling in the first direction in the second and third application steps in the second direction. To the surface of the current collector foil PEP. In other words, the plurality of first insulating materials IF1 has the width in the second direction of the region of the positive electrode material PAS applied to the surface of the current collector foil PEP that travels in the first direction in the second and third application steps. Applied to regulate. In Embodiment 3, in order to form two rows of positive electrode films along the first direction on the surface of the current collector foil PEP, the plurality of first insulating materials IF1 are separated from each other in the second direction, and the current collector foil Three rows are applied to the surface of the PEP along the first direction.

The thickness of the first insulating material IF1 is substantially the same as the thickness of the positive electrode material PAS applied to the surface of the current collector foil PEP in the subsequent second and third application steps. In addition, since the region to which the first insulating material IF1 is applied is a region that is cut after the positive electrode sheet is completed, the width in the second direction of the first insulating material IF1 is set to be small in order to reduce the material cost. The For example, considering the width required for cutting, the width in the second direction of the first insulating material IF1 is about 5 to 15 mm.

2. Second application process (first electrode material application process)
Next, the slurry-like first positive electrode material PAS1 supplied from the first slit die coater DC1 at a position facing the fourth roller RL4 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The first positive electrode material PAS1 is stored in the tank TA2, and is supplied to the surface of the current collector foil PEP by the metering pump PU2.

As shown in FIG. 7B, the plurality of first positive electrode materials PAS1 are applied to the surface of the current collector foil PEP traveling in the first direction and to the surface of the current collector foil PEP in the previous first application step. It is applied to a region sandwiched between the first insulating materials IF1. In Embodiment 3, in order to form two rows of positive electrode films along the first direction on the surface of the current collector foil PEP, the plurality of first positive electrode materials PAS1 are separated by the first insulating material IF1 and second Two rows are applied along the first direction to the surface of the current collector foil PEP.

The thickness of the first positive electrode material PAS1 is smaller than the thickness of the first insulating material IF1 applied to the surface of the current collector foil PEP in the previous first application step. That is, the upper surface of the first positive electrode material PAS1 is at a position lower than the upper surface of the first insulating material IF1. The thickness of the first positive electrode material PAS1 can be adjusted, for example, by adjusting the height of the base D1 of the first slit die coater DC1 (see FIG. 10) and feeding the first positive electrode material PAS1.

3. Third application process (second electrode material application process)
Next, the slurry-like second positive electrode material PAS2 supplied from the second slit die coater DC2 at a position facing the fifth roller RL5 is applied to the surface of the current collector foil PEP fed from the unwinding roll SL1. The second positive electrode material PAS2 is stored in the tank TA3, and is supplied to the upper surface of the first positive electrode material PAS1 by the metering pump PU3. Here, the binder content of the second positive electrode material PAS2 is smaller than the binder content of the first positive electrode material PAS1.

As shown in FIG. 7C, the second positive electrode material PAS2 is applied to the upper surface of the first positive electrode material PAS1, and the positive electrode material PAS formed by laminating the first positive electrode material PAS1 and the second positive electrode material PAS2 is formed. It is formed.

The second positive electrode material PAS2 is applied so that the height from the surface of the current collector foil PEP to the upper surface of the positive electrode material PAS is substantially the same as the height from the surface of the current collector foil PEP to the upper surface of the first insulating material IF1. The That is, the thickness of the positive electrode material PAS is substantially the same as the thickness of the first insulating material IF1 applied to the surface of the current collector foil PEP in the previous first application step. Although the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 are desirably the same, in order to prevent the second positive electrode material PAS2 from being applied to the upper surface of the first insulating material IF1, However, the second positive electrode material PAS2 is applied so as to be lower by about 0 μm to 10 μm than the upper surface of the first insulating material IF1. The thickness of the second positive electrode material PAS2 can be adjusted, for example, by adjusting the height of the die D1 of the second slit die coater DC2 (see FIG. 10) and the feed amount of the second positive electrode material PAS2.

In the third embodiment, the positive electrode material PAS is configured by laminating the first positive electrode material PAS1 and the second positive electrode material PAS2 having different binder contents. This is due to the following reason.

First, a problem when the positive electrode material PAS is formed of a single layer will be described. The slurry-like positive electrode material PAS contains a binder for binding the active material and the conductive auxiliary agent in addition to the active material and the conductive auxiliary agent. However, this binder tends to segregate on the upper surface side of the positive electrode material PAS in the drying process, and if the binder content is too small, this causes the positive electrode material PAS at the interface between the current collector foil PEP and the positive electrode material PAS. May peel off. In particular, when the positive electrode material PAS is thickly coated, the segregation of the binder becomes remarkable, and the peeling of the positive electrode material PAS becomes a serious problem. On the other hand, by increasing the content of the binder contained in the positive electrode material PAS, the segregation of the binder can be made difficult to occur. However, if the binder content is too large, the amount of the active material is reduced and the battery capacity is lowered, or the binder is difficult to mix, and thus the current distribution of the positive electrode film varies. For this reason, there is also a trade-off between the viscosity and surface tension of the positive electrode material PAS, and it is difficult to adjust the binder content contained in the positive electrode material PAS to the optimum content. In particular, when the positive electrode material PAS is thickly coated Therefore, it becomes more difficult to adjust the binder content.

However, in the third embodiment, the first positive electrode material PAS1 having a relatively high binder content is applied, and the second positive electrode material PAS2 having a relatively low binder content is applied thereon. In the drying process, the first positive electrode material PAS1 and the second positive electrode material PAS2 are mixed, but when the positive electrode material PAS is coated with two layers of the first positive electrode material PAS1 and the second positive electrode material PAS2, Since the segregation of the binder on the upper surface side of the positive electrode material PAS is less than when the positive electrode material PAS is coated, in the third embodiment, the positive electrode material PAS can be prevented from peeling off.

Further, in order to set the optimum binder content, for example, the first positive electrode material PAS1 and the second positive electrode material PAS2 having such viscosity and surface tension that the side surfaces of the first positive electrode material PAS1 and the second positive electrode material PAS2 are inclined. May have to be used. However, even in such a case, in the third embodiment, the first insulating material IF1 prescribes the region where the first positive electrode material PAS1 and the second positive electrode material PAS2 are applied. The shapes of the positive electrode material PAS1 and the second positive electrode material PAS2 are stable.

4). Fourth coating process (second insulating material (separator material) coating process)
Next, in the same manner as the third application process (second insulating material (separator material) application process) of the first embodiment described above, the slurry state supplied from the third slit die coater DC3 at a position facing the sixth roller RL6. The second insulating material IF2 is applied. The second insulating material IF2 is stored in the tank TA4, and is supplied to the upper surfaces of the first insulating material IF1 and the second positive electrode material PAS2 by the metering pump PU4.

As shown in FIG. 7D, the second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS along the first direction in which the current collector foil PEP travels. The thickness of the second insulating material IF2 is, for example, about 5 μm to 40 μm. The thickness of the second insulating material IF2 can be adjusted, for example, by adjusting the height of the base D1 of the third slit die coater DC3 (see FIG. 10) and feeding the second insulating material IF2.

5. Next, similarly to the drying process of the first embodiment, the positive electrode material PAS and the first insulating material IF1 applied to the surface of the current collector foil PEP by passing through the drying furnace (drying mechanism) DRY The entire coating film obtained by laminating the second insulating material IF2 applied to these upper surfaces is dried, and the current collector foil PEP having the positive electrode film and the separator formed on the surface is wound on the winding roll SL2.

As shown in FIG. 7 (e), the first positive electrode material PAS1 and the second positive electrode material PAS2 are mixed to form a single-layer positive electrode material PAS. In addition, the thickness of the positive electrode material PAS and the thickness of the first insulating material IF1 were substantially the same before drying, but after drying, the amount of solids contained in the first positive electrode material PAS1 and the second positive electrode material PAS2 The thickness of the spacer SP made of the first insulating material IF1 is thinner than the thickness of the positive electrode film PE made of the positive electrode material PAS because of the difference between the amount of the solid matter contained in the first insulating material IF1.

In the third embodiment, the method of manufacturing the positive electrode film PE formed in two rows on the surface of the current collector foil PEP along the first direction in which the current collector foil PEP travels is exemplified, but the present invention is not limited thereto. It is not something. For example, the positive electrode film PE may be one row or three or more rows, and the same effect can be obtained.

In the third embodiment, the positive electrode material PAS is configured by two layers of the first positive electrode material PAS1 and the second positive electrode material PAS2 having different binder contents. However, the present invention is not limited to this. The positive electrode material PAS may be composed of three or more layers having different contents.

As described above, according to the third embodiment, by forming the positive electrode material PAS by stacking the first positive electrode material PAS1 and the second positive electrode material PAS2, the segregation of the binder on the upper surface side of the positive electrode material PAS is reduced. Thus, peeling of the positive electrode material PAS can be prevented. In addition, since the region where the first positive electrode material PAS1 and the second positive electrode material PAS2 are applied is defined in advance by the first insulating material IF1, the shapes of the first positive electrode material PAS1 and the second positive electrode material PAS2 are stable. Further, even if the second insulating material IF2 to be the separator SE is thinly applied, the film of the second insulating material IF2 does not break, so that the second insulating material IF2 can be thinly and uniformly applied. Thereby, it is possible to reduce the thickness of the separator SE and the electrode film without reducing the production yield of the lithium ion battery.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

D1 Base D2 Manifold D3 Slit D4 Electrode material reservoir D5 Downstream meniscus (bending of liquid level)
D6 Downstream lip portion DC1 First slit die coater DC2 Second slit die coater DC3 Third slit die coater DP Dispenser DRY Drying furnace h1 First interval IF Insulating material IF1 First insulating material IF2 Second insulating material M1 Electrode sheet manufacturing apparatus M2 Electrode sheet Manufacturing apparatus M3 Electrode sheet manufacturing apparatus PAS Positive electrode material PAS1 First positive electrode material PAS2 Second positive electrode material PE Positive electrode film PEP Current collector foil PU1, PU2, PU3, PU4 Metering pump RL1 First roller RL2 Second roller RL3 Third roller RL4 First 4 roller RL5 5th roller RL6 6th roller RL7 7th roller RL8 8th roller SE Separator SL1 Unwinding roll SL2 Winding roll SP Spacer TA1, TA2, TA3, TA4 Tank

Claims

A transport mechanism for transporting the current collector foil in the first direction;
A first application in which a slurry-like first insulating material is applied to a plurality of first regions spaced from each other in a second direction orthogonal to the first direction and the surface of the current collector foil on the surface of the current collector foil Mechanism,
A second application mechanism for applying a slurry-like first electrode material to a second region sandwiched between the first regions adjacent to each other in the second direction on the surface of the current collector foil;
A third application mechanism for applying a slurry-like second insulating material on top surfaces of the first insulating material and the first electrode material;
An apparatus for manufacturing an electricity storage device.
The apparatus for manufacturing an electricity storage device according to claim 1,
A drying mechanism for drying the first electrode material, the first insulating material, and the second insulating material;
An apparatus for manufacturing an electricity storage device, further comprising:
The apparatus for manufacturing an electricity storage device according to claim 1,
The electrical storage device manufacturing apparatus, wherein the first application mechanism, the second application mechanism, and the third application mechanism are sequentially installed in the first direction.
In the manufacturing apparatus of the electrical storage device according to claim 3,
Between the second application mechanism and the third application mechanism,
A fourth application mechanism for applying a slurry-like second electrode material on the upper surface of the first electrode material;
An apparatus for manufacturing an electricity storage device, further comprising:
The apparatus for manufacturing an electricity storage device according to claim 1,
The electrical storage device manufacturing apparatus, wherein the second application mechanism, the first application mechanism, and the third application mechanism are sequentially installed in the first direction.
In the manufacturing apparatus of the electrical storage device of any one of Claims 1-5,
The first application mechanism has a dispenser, and the second application mechanism and the third application mechanism have a slit die coater.
(A) A step of applying a plurality of slurry-like first insulating materials separated from each other in a second direction orthogonal to the first direction and the surface of the current collector foil on the surface of the current collector foil traveling in the first direction ,
(B) After the step (a), applying a slurry-like electrode material to the surface of the current collector foil sandwiched between the first insulating materials adjacent in the second direction;
(C) After the step (b), applying a slurry-like second insulating material on the electrode material and the upper surface of the first insulating material;
(D) after the step (c), drying the electrode material, the first insulating material, and the second insulating material;
A method for manufacturing an electricity storage device.
(A) applying a slurry-like electrode material to the surface of the current collector foil traveling in the first direction;
(B) After the step (a), a slurry-like first insulating material is formed on the surface of the current collector foil on both sides of the electrode material in the second direction perpendicular to the first direction and the surface of the current collector foil. The step of applying,
(C) After the step (b), applying a slurry-like second insulating material on the electrode material and the upper surface of the first insulating material;
(D) after the step (c), drying the electrode material, the first insulating material, and the second insulating material;
A method for manufacturing an electricity storage device.
In the manufacturing method of the electrical storage device of Claim 7,
In the step (b), a method for manufacturing an electricity storage device, wherein a plurality of electrode materials having different binder contents are laminated.
In the manufacturing method of the electrical storage device of Claim 7 or 8,
The method for manufacturing an electricity storage device, wherein the width of the first insulating material in the second direction is about 5 mm to 15 mm.
In the manufacturing method of the electrical storage device of Claim 7 or 8,
In the step (b), the method for manufacturing an electricity storage device, wherein the upper surface of the electrode material is 0 μm to 10 μm lower than the upper surface of the first insulating material.
In the manufacturing method of the electrical storage device of Claim 7 or 8,
The method for manufacturing an electricity storage device, wherein the thickness of the second insulating material applied in the step (c) is 5 μm to 40 μm.