KR101773728B1 - Apparatus for manufacturing power storage device, and method for manufacturing power storage device - Google Patents

Abstract

Thereby improving the production yield of power storage devices such as lithium ion batteries. Means for Solving the Problems In order to solve the above problems, in a power storage sheet manufacturing apparatus, a dispenser, a first slit die coater, and a second slit die coater are sequentially disposed in a first direction in which a current collecting foil travels. The dispenser is formed by applying a plurality of first insulating materials in a slurry form to a surface of a current collecting foil, the first slit die coater applying a slurry-like cathode material to a surface of the current collecting foil, A second insulating material in slurry form is applied to the upper surface of the cathode material. Further, the plurality of first insulating materials are applied apart from each other in the second direction orthogonal to the first direction, and the cathode material is applied between the first insulating films adjacent to each other in the second direction.

Description

[0001] Apparatus for manufacturing power storage device and method for manufacturing power storage device [0002]

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

Japanese Unexamined Patent Publication No. 2003-045491 (Patent Document 1) is known as a background art in this technical field. This publication discloses an apparatus for feeding a cathode sheet material, a cathode electrode material coating mechanism, a heating mechanism for forming an anode electrode, an electrolytic and insulating material coating mechanism, a heating mechanism for electrolytic and insulating material formation, And a secondary battery manufacturing apparatus provided with a cathode electrode material coating mechanism, a cathode electrode heating mechanism, an electrolytic and insulating material coating mechanism, a heating mechanism for forming an insulating material, and a winding mechanism. The winding mechanism is a mechanism for winding a positive electrode sheet material on which a positive electrode material, an electrolytic or insulating material are fixed, a negative electrode material, and a negative electrode sheet material on which an electrolytic or insulating material is fixed, and winding them into a predetermined shape.

In Patent Document 1, an electrode material of an anode or a cathode (also referred to as an electrode material, an electrode active material or the like) is applied to both surfaces of a current collector foil (metal foil, electrode plate, substrate, (Hereinafter also referred to as " electrolytic " or " insulating material ") to be a separator to be continuously provided on a material, it is possible to improve the production efficiency of the secondary battery and make the production apparatus of the secondary battery compact.

However, in such a method of manufacturing a secondary battery, when the thickness of the insulating material is, for example, about 5 mu m to 40 mu m, the insulating material may be broken to cause the electrode material to be exposed. Further, when an electrode material having a thickness of, for example, 100 mu m to 400 mu m is applied, the side surface of the electrode material tilts and the thickness of the electrode material becomes uneven, and an electrode material of a desired shape can not be formed . There is a problem that the production yield of the secondary battery is lowered because of these.

Patent Document 1: Japanese Patent Laid-Open No. 2003-045491

Other tasks and novel features will become apparent from the description of the present specification and the accompanying drawings.

The apparatus for manufacturing an electrical storage device according to an embodiment comprises a plurality of slurry-like first insulating materials which are separated from each other in a first direction and a second direction orthogonal to the surface of the current collecting foil on the surface of the current collecting foil running in the first direction And a second coating mechanism for applying a slurry-like electrode material to the surface of the current collecting foil sandwiched by the first insulating material adjacent in the second direction. And a third application mechanism that applies a slurry-like second insulating material to the upper surface of the first insulating material and the electrode material.

A method of manufacturing an electrical storage device according to an embodiment is a method of coating a plurality of slurry-like first insulating materials on a surface of a current collecting foil running in a first direction, the first insulating materials being separated from each other in a first direction and a second direction orthogonal to the current collecting foil surface A step of applying a slurry-like electrode material to a surface of a current collecting foil sandwiched by a first insulating material adjacent in a second direction, a step of applying a slurry-like second insulating material to the upper surface of the first insulating material and the electrode material .

According to one embodiment, the production yield of a battery device such as a lithium ion battery can be improved.

1 is a schematic view of an apparatus for manufacturing an electrode sheet of a lithium ion battery according to Example 1. Fig.
Fig. 2 is a cross-sectional view of an electrode sheet in each coating step and drying step for explaining a method for producing an electrode sheet of a lithium ion battery according to Embodiment 1, wherein (a) shows the electrode sheet of the first insulating material (spacer material) (B) is a cross-sectional view (B1-B1 sectional view in Fig. 1) of the electrode sheet in the electrode material applying step, and Fig. 1 is a cross-sectional view (C1-C1 sectional view in Fig. 1) of the electrode sheet, and (d) is a sectional view (D1-D1 sectional view in Fig.
Fig. 3 is a process chart showing a specific manufacturing process of a lithium ion battery in Example 1. Fig.
4 is a schematic view of an apparatus for producing an electrode sheet of a lithium ion battery according to Embodiment 2. Fig.
5 is a cross-sectional view of an electrode sheet in a coating step and a drying step for explaining a method for producing an electrode sheet of a lithium ion battery according to Example 2, wherein (a) is a sectional view of the electrode sheet in the electrode material applying step (Sectional view taken along the line B2-B2 of Fig. 4) of the electrode sheet of the first insulating material (spacer material) coating process, and Fig. 4 is a cross-sectional view (C2-C2 sectional view in Fig. 4) of the electrode sheet in the drying step, and Fig. 4 (d) is a sectional view (D2-D2 sectional view in Fig.
6 is a schematic view of an apparatus for producing an electrode sheet of a lithium ion battery according to Embodiment 3. Fig.
Fig. 7 is a cross-sectional view showing the principal part of an electrode sheet in each coating step and drying step for explaining a method for producing an electrode sheet of a lithium ion battery in Example 3, wherein (a) (B) is a cross-sectional view (B3-B3 cross-sectional view of Fig. 6) of the electrode sheet in the first electrode material application step, and Fig. (D) is a cross-sectional view (D3-D3 sectional view in Fig. 6) of the electrode sheet in the second insulating material (separator material) application step, and (e) (Sectional view taken along the line E3-E3 in Fig. 6).
FIG. 8 is a process chart showing a specific manufacturing process of a lithium ion battery shown as a comparative example. FIG.
9 is a schematic view of an apparatus for producing an electrode sheet of a lithium ion battery as a comparative example.
10 is a cross-sectional view schematically illustrating the application state of slurry-based electrode material by a slit die coater.

In the following embodiments, when referring to the number (including the number, the numerical value, the amount, the range, etc.) of the elements, and the like, unless otherwise specified and in principle limited to a specific number, But the number may be more or less than a certain number.

In the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless specifically stated or in principle considered to be absolutely essential.

It is also possible to exclude other elements except "A", "A", "A", and "including A" Of course not. Likewise, in the following embodiments, when referring to the shape, positional relationship, and the like of constituent elements and the like, substantially similar or similar to the shape or the like, unless otherwise specified or in principle, And the like. This is also the same for the numerical value and the range.

In the drawings used in the following embodiments, hatching is given to make the drawings easy to see even in a plan view. In all the drawings for explaining the following embodiments, those having the same functions are denoted by the same reference numerals, and repetitive description thereof will be omitted. Hereinafter, embodiments will be described in detail with reference to the drawings.

In the following description, the cathode material and the anode material are collectively referred to as " electrode material ", the film made of the cathode material after the drying process is referred to as the " anode film ", the film made of the cathode material after the drying process is referred to as " The films are collectively referred to as " electrode films ". In the following description, the cathode material, the cathode material and the insulating material before the drying process are liquid materials including a liquid such as a binder solution and an organic solvent. In the following description, the collective foil formed with the positive electrode film is referred to as a " positive electrode sheet (also referred to as a positive electrode plate) ", the current collecting foil formed with the negative electrode film is referred to as a " negative electrode sheet An electrode sheet (also referred to as an electrode plate or the like) ". In the following description, the term " current collecting foil surface " refers only to the side surface of the current collecting foil and not to the front including the side surface. In the following description, the direction in which the current collecting foil travels is referred to as a " first direction ", and the direction orthogonal to the first direction and the current collecting foil surface is referred to as a " second direction ".

In the present embodiment, a lithium ion battery is exemplified as a secondary battery that is a power storage device, the manufacturing apparatus and the manufacturing method thereof are described, but the present invention is not limited thereto.

A lithium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which lithium ions in an electrolyte take charge of electric conduction.

For example, a lithium-containing complex oxide is used for the anode and a carbonaceous material is used for the cathode. As the electrolyte, for example, an organic solvent such as ethylene carbonate or a lithium salt such as lithium hexafluorophosphate (LiPF6) is used. In a lithium ion battery, at the time of charging, lithium ions come out of the positive electrode and enter the negative electrode, and when discharging, lithium ions come out of the negative electrode and enter the positive electrode.

The lithium ion battery includes a positive electrode sheet obtained by coating a positive electrode material on the surface of a current collector foil (for example, an Al foil) and a negative electrode material on the surface of a current collector foil (for example, a Cu And an electrode winding body in which a separator such as a polymer film for preventing contact between the positive electrode film and the negative electrode film is wound. In the lithium ion battery, the electrode winding body is inserted into the external can and the electrolyte (the electrolyte) is injected into the external can.

That is, in the lithium ion battery, the positive electrode sheet coated with the positive electrode material on the surface of the current collecting foil and the negative electrode sheet coated with the negative electrode material on the surface of the current collector foil are formed in a strip shape, and the positive electrode sheet and the negative electrode sheet, The electrode winding is formed by being wound in a cross-section swirl through the separator so that the sheet-like positive electrode film and the negative electrode film on the negative electrode sheet do not directly contact each other.

(Comparative Example)

First, since it is considered that the manufacturing apparatus and the manufacturing method of the lithium ion battery according to the present embodiment become clearer, as a comparative example, the apparatus for manufacturing a lithium ion battery before the application of the present invention, The manufacturing method will be described below.

Fig. 8 is a process drawing incorporating 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 manufacturing process of a positive electrode sheet, a manufacturing process of a negative electrode sheet, a battery cell assembling process, and a battery module assembling process.

In the production process of the positive electrode sheet, first, a slurry-like positive electrode material is applied to the surface of the current collecting foil on the film (positive electrode material application), and then the upper surface and the side surface of the positive electrode material and the separator The slurry-like insulating material is applied (separator material application). Subsequently, the entire coating film obtained by laminating the slurry-like cathode material and the slurry-like insulating material is dried (dried), and then the current collector foil, in which the anode film made of the anode material and the laminated film made of the insulating material are formed, (Processed), a positive electrode film and a separator.

On the other hand, in the production process of the negative electrode sheet, the various materials to be used as raw materials are different from the production process of the positive electrode sheet, but the order in which the negative electrode sheet is produced is the same as the production process of the positive electrode sheet. First, a slurry-like negative electrode material is applied to the surface of the current collecting foil on the film (negative electrode material application), and then a slurry-like insulating material serving as a separator is coated on the top and sides of the negative electrode material and on the surface of the current- (Separator material application). Subsequently, the entire coating film obtained by laminating the slurry-like negative electrode material and the slurry-like insulating material was dried (dried), and then a current collector foil having a laminate film of a negative electrode film made of a negative electrode material and a separator made of an insulating material was formed. (Processed) to produce a negative electrode sheet on a film having a negative electrode film and a separator.

Next, in the battery cell assembling step, a positive electrode of a required size is cut out from the film-shaped positive electrode sheet, a negative electrode of a required size is cut out from the negative electrode sheet on the film, and the positive electrode and the negative electrode are stacked (Circulation). Since the separator is already formed in the positive electrode sheet and the negative electrode sheet, it is not necessary to wind the separator between the positive electrode and the negative electrode so that the manufacturing cost of the lithium ion battery can be reduced.

Next, a group of electrode pairs of positive and negative electrodes wound together is assembled and welded (welding / assembling). Subsequently, the group of the electrode pairs welded is placed in the battery can with the electrolyte injected thereinto (injection), and the battery can is completely sealed (sealed) to prepare the battery cell.

Next, the produced battery cell is repeatedly charged and discharged (charge and discharge), and the performance and reliability of the battery cell (for example, the capacity and voltage of the battery cell and the current and voltage during charging or discharging of the battery cell, Voltage, etc.) is performed (single cell inspection). Thus, the battery cell is completed, and the battery cell assembling process is completed.

Next, in the battery module assembling step, a plurality of battery cells are combined in series to constitute a battery module, and a charge / discharge controller is connected to constitute a battery system (module assembly). Subsequently, an inspection as to the performance and reliability of the assembled battery module (e.g., inspection of the capacity and voltage of the battery module and current and voltage at the time of charging or discharging of the battery module) is performed (module inspection). Thus, the battery module is completed, and the battery module assembling process is completed.

9 is a schematic view of an apparatus for producing an electrode sheet of a lithium ion battery as a comparative example. In Fig. 9, a manufacturing process of one surface of a positive electrode sheet is illustrated. Although not described here, the manufacturing process of one side of the negative electrode sheet is also the same.

As shown in Fig. 9, the current collecting foil PEP is fed from the take-up roll SL1 and passes through 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 to the winding roll SL2. A first slit die coater DC1 is provided opposite to the third roller RL3 and a second slit die coater DC2 is provided opposite to the fourth roller RL4.

First, a slurry-like cathode material PAS supplied from the first slit die coater DC1 at a position opposed to the third roller RL3 is coated on the surface of the current collecting foil PEP sent out from the winding roll SL1 do. The cathode material PAS is stored in the tank TA1 and supplied to the surface of the current collecting foil PEP by the metering pump PU1.

Then, the slurry-like insulating material IF supplied from the second slit die coater DC2 at a position opposed to the fourth roller RL4 is coated. The insulating material IF is stored in the tank TA2 and supplied to the surface of the current collecting foil PEP coated with the cathode material PAS by the metering pump PU2. That is, the insulating material IF is applied to the top surface and the side surface of the cathode material PAS and the surface of the current collecting foil PEP on which the cathode material PAS is not applied.

Subsequently, a current collecting foil (PEP) having a coating film formed on the entire surface of the coated film which is formed by laminating the cathode material (PAS) and the insulating material (IF) formed on the surface of the current collecting foil (PEP) Is wound on the winding roll SL2.

10 is a cross-sectional view schematically illustrating the state of application of the slurry-like cathode material (PAS) by the first slit-die coater DC1. But the application state of the slurry-like insulating material IF by the second slit die coater DC2 is also the same.

As shown in Fig. 10, a slurry-like cathode material PAS is supplied to the manifold D2 of the mouthpiece D1 by a metering pump from a tank in which the slurry-like cathode material PAS is stored. After the pressure distribution of the slurry-like cathode material PAS becomes uniform in the manifold D2, the slurry-like cathode material PAS is supplied to the slit D3 provided in the mouthpiece D1 and is discharged . The discharged slurry-like cathode material PAS is held between the mouthpiece D1 and the current collecting foil PEP, which maintains a first gap h1 from the mouthpiece D1 and runs relatively to the mouthpiece D1, (D4) is formed. In this state, the slurry-like cathode material (PAS) is pulled out along with the running of the current collecting foil (PEP) to form a coating film made of the cathode material (PAS).

Here, the coating film is continuously formed by supplying the cathode material PAS of the same amount as the cathode material PAS consumed by the formation of the coating film from the slit D3. Stabilization of the meniscus (liquid level bending) D5 on the downstream side of the electrode material mass D4 becomes important in order to stably apply the organic solvent-based cathode material (PAS) with a high evaporation rate. Therefore, the pressure for supplying the cathode material PAS to the manifold D2 is equal to or higher than the pressure loss of the slit portion D3 + the pressure loss of the downstream side lip portion D6 of the mouthpiece D1 + (I.e., the pressure at the point D5).

The present inventors have studied the high capacity and miniaturization of a lithium ion battery, and as a means thereof, the thinning of the separator and the thickening of the electrode film (anode film and cathode film) are studied.

However, in order to form the separator thin, it is necessary to make the first gap h1 between the mouthpiece D1 of the second slit die coater DC2 and the current collecting foil PEP small. However, Is too large, the insulating material (IF) can not be uniformly applied, and the film breakage occurs in the separator. Further, even if the insulating material IF can be uniformly applied to the upper surface of the electrode material, the insulating material IF can not be uniformly applied to the side surface of the electrode material and the surface of the current collecting foil (PEP) . In order to form the electrode film thick, the electrode material must be applied thickly on the surface of the current collecting foil (PEP). However, if the electrode material is thickly coated, the side surface of the electrode material tilts And the concave portion is formed on the upper surface of the electrode material, so that the shape of the electrode material is not stable. Therefore, there has been a problem that when the separator is made thinner and the electrode film is made thicker, the production yield of the lithium ion battery is lowered.

(Example 1)

<< Method of producing electrode sheet of lithium ion battery >>

A method of manufacturing an electrode sheet of a lithium ion battery in the first embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a schematic view of an apparatus for manufacturing an electrode sheet of a lithium ion battery according to the first embodiment. Fig. 2 is a cross-sectional view of the electrode sheet in each of the coating step and the drying step for explaining the method of manufacturing the electrode sheet of the lithium ion battery in the first embodiment. Fig. Fig. 2 (a) is a sectional view (A1-A1 sectional view in Fig. 1) of the electrode sheet in the first insulating material (spacer material) Sectional view of the electrode sheet in the second insulation material (separator material) application process (C1-C1 sectional view in Fig. 1). Fig. 2 (d) is a sectional view (D1-D1 sectional view in Fig. 1) of the electrode sheet in the drying step.

In the first embodiment, a method of manufacturing a positive electrode film formed in two rows on the surface of a current collecting foil along a first direction in which the current collecting foil travels is exemplified. In the first embodiment, a manufacturing method of one surface of a positive electrode sheet is exemplified, but a manufacturing method of a negative electrode sheet is also the same.

As shown in Fig. 1, in the electrode sheet producing apparatus M1, the current collecting foil PEP is fed from the take-up roll SL1 and passes through the first roller RL1, the second roller RL2, And is conveyed to the winding roll SL2 by the fourth roller RL3, the fourth roller RL4, the fifth roller RL5, the sixth roller RL6 and the seventh roller RL7. A first slit die coater DC1 is provided so as to face the fourth roller RL4 and a second slit die coater DC1 is provided so as to face the fifth roller RL5, A die coater DC2 is provided.

1. First coating step (first insulating material (spacer material) coating step)

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 collecting foil PEP sent out from the unwinding roll SL1. The first insulating material IF1 is stored in the tank TA1 and supplied to the surface of the current collecting foil PEP by the metering pump PU1.

2A, a plurality of first insulating materials IF1 are formed on the surface of a current collecting foil PEP running in a first direction, In the second direction. That is, the plurality of first insulating materials IF1 are formed so as to cover the region where the cathode material PAS is applied on the surface of the current collecting foil PEP running in the first direction in the subsequent second coating process, Is applied to the surface of the current collecting foil (PEP). In other words, the plurality of first insulating materials IF1 are formed so that the width in the second direction of the region of the cathode material (PAS) applied to the surface of the current collecting foil PEP running in the first direction in the subsequent second coating process Regulated. In the first embodiment, a plurality of first insulating materials IF1 are separated from each other in the second direction so as to form two rows of anode films along the first direction on the surface of the current collecting foil (PEP) ) Along the first direction.

The thickness of the first insulating material IF1 is substantially equal to the thickness of the cathode material PAS applied to the surface of the current collecting foil PEP in the subsequent second coating step. Since the region to which the first insulating material IF1 is to be applied is a region to be cut after the cathode sheet is completed, the width of the first insulating material IF1 in the second direction is set small to suppress the material cost. For example, in consideration of the width required for cutting, the width of the first insulating material IF1 in the second direction is about 5 mm to 15 mm.

2. Second Coating Process (Electrode Material Coating Process)

Next, a slurry-like cathode material PAS supplied from the first slit die coater DC1 at a position opposed to the fourth roller RL4 is wound on the surface of the current collecting foil PEP sent out from the take-up roll SL1 . The cathode material PAS is stored in the tank TA2 and supplied to the surface of the current collecting foil PEP by the metering pump PU2.

As shown in Fig. 2 (b), the plurality of cathode materials PAS are formed on the surface of the current collecting foil PEP running in the first direction and on the surface of the current collecting foil PEP in the first first coating process And is applied to a region sandwiched between the applied first insulating material IF1. In the first embodiment, a plurality of anode materials (PAS) are separated by the first insulating material IF1 to form a two-row anode film along the first direction on the surface of the current collecting foil (PEP) , And two rows are coated on the surface of the current collecting foil (PEP) along the first direction.

The thickness of the anode material (PAS) is almost the same as the thickness of the first insulating material (IF1). It is preferable that the thickness of the cathode material PAS and the thickness of the first insulating material IF1 are equal to each other. However, in order to prevent the cathode material PAS from being applied to the upper surface of the first insulating material IF1, Is lower than the upper surface of the first insulating material IF1 by about 0 mu m to 10 mu m. The thickness of the anode material PAS can be adjusted by, for example, adjusting the height of the mouthpiece D1 of the first slit die coater DC1 (see Fig. 10) and feeding the cathode material PAS.

When the first insulating material IF1 is not applied, when the cathode material PAS is thickly coated, the side faces of the cathode material PAS are inclined and the concave portions are formed on the upper surface of the cathode material PAS, There is a problem that the shape of the cathode material (PAS) is not stable. However, in the first embodiment, since the region to which the cathode material PAS is applied is previously defined by the first insulating material IF1, the cathode material PAS is thick (for example, about 100 to 400 mu m) Even when applied, since the side surface of the cathode material PAS is not inclined, the shape of the cathode material PAS is stabilized.

3. Third Coating Process (Second Insulating Material (Separator Material) Coating Process)

Next, the slurry-like second insulating material IF2 supplied from the second slit die coater DC2 at a position opposed to the fifth roller RL5 is applied. The second insulating material IF2 is stored in the tank TA3 and supplied to the upper surface of the first insulating material IF1 and the cathode material PAS by the metering pump PU3.

The second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS along the first direction in which the current collecting foil PEP travels, as shown in Fig. 2 (c) do. The thickness of the second insulating material IF2 is, for example, about 5 mu m to 40 mu m. The thickness of the second insulating material IF2 is adjusted by adjusting the height of the mouthpiece D1 of the second slit die coater DC2 (see FIG. 10) and the amount of the second insulating material IF2 .

In order to apply the second insulating material IF2 thinly, as shown in Fig. 10, the first gap h1 (between the cap Dl of the second slit die coater DC2 and the current collecting foil PEP) Is required to be small. However, the second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS which are substantially planar surfaces and the side surfaces of the first insulating material IF1 and the cathode material PAS, And the current collecting foil (PEP) on which the first insulating material IF1 and the cathode material PAS are not applied. Therefore, even if the first gap h1 between the aperture diaphragm D1 of the second slit die coater DC2 and the current collecting foil PEP is small, the second insulating material IF2 can be uniformly applied , The film breakage of the second insulating material IF2 can be prevented.

4. Drying process

Next, the positive electrode material PAS and the first insulating material IF1 applied to the surface of the current collecting foil PEP and the first insulating material IF1 passing through the drying furnace (drying mechanism) DRY and the second insulation The whole of the coated film obtained by laminating the material IF2 is dried, and the current collecting foil PEP on which the anode film and the separator are formed is wound around the winding roll SL2.

2 (d), before the drying, the thickness of the cathode material PAS and the thickness of the first insulating material IF1 were almost the same, but after drying, the spacers made of the first insulating material IF1 The thickness of the positive electrode film SP is thinner 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 the solid material (for example, the positive electrode active material and the conductive auxiliary agent) contained in the positive electrode material (PAS) and the amount of the solid matter contained in the first insulating material (IF1). That is, the amount of the solid material contained in the cathode 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 so that after the drying, And is made thinner than the thickness of the film (PE).

This is for the following reasons. That is, in order to improve the adhesion between the current collecting foil (PEP) and the anode film (PE) and to bond the solids in the cathode material (PAS) to each other, an anode film (PE) and a spacer (Roll press) of this laminated film is performed before the laminated film of the coated second insulating material IF2 and the separator SE is cut. It is important to apply a load to the positive electrode film PE at the time of compression so that no load is applied to the positive electrode film PE if the thickness of the spacer SP is larger than the thickness of the positive electrode film PE. Therefore, it is necessary to make the thickness of the spacer SP thinner than the thickness of the anode film PE.

On the other hand, in Embodiment 1, a method of manufacturing a positive electrode film (PE) formed in two rows on the surface of a current collecting foil (PEP) along the first direction in which the current collecting foil PEP travels is exemplified. For example, the anode film (PE) may be one column or three or more columns, and the same effect can be obtained.

<< Detailed Manufacturing Process of Lithium Ion Battery >>

A specific manufacturing process of the lithium ion battery in the first embodiment will be described with reference to FIG. 3 is a process diagram incorporating the 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 similar to the manufacturing process of the lithium ion battery shown in Fig. 8 except that the positive electrode sheet manufacturing step, the negative electrode sheet manufacturing step, the battery cell assembling step, And assembly process.

In the process of manufacturing the positive electrode sheet, first, a plurality of first insulating materials in a slurry to be spacers are applied to the surface of the current collecting foil on the film in a second direction orthogonal to the first direction in which the current collecting foil travels apply). The first insulating material is produced by kneading and combining various materials as raw materials.

Subsequently, on the surface of the current collecting foil on the film, the slurry-like cathode material is applied between the first insulating materials which are applied mutually to each other in the second direction (cathode material application). The cathode material is produced by kneading and combining various materials as raw materials.

Next, a slurry-like second insulating material to be a separator is applied (separator material application) to the upper surface of the first insulating material and the cathode material formed on the surface of the current collecting foil on the film. The second insulating material is produced by kneading and combining various materials as raw materials.

Subsequently, the entirety of the coated film obtained by laminating the cathode material and the first insulating material coated on the surface of the current collecting foil on the film and the second insulating material coated on the upper surface thereof was dried (dried) And processing of cutting is performed (processing). Thereby, on the surface of the current collecting foil on the film, a positive electrode sheet on which a positive electrode made of a positive electrode material, a spacer made of a first insulating material, and a separator made of a second insulating material formed on the top surface thereof are laminated is produced. When the current collecting foil on which the coating film is formed is cut, the region where the spacer made of the first insulating material is formed is cut.

On the other hand, in the process of manufacturing the negative electrode sheet, various materials as raw materials to be used are different from the positive electrode sheet production process, but the order in which the negative electrode sheet is produced is the same as the manufacturing process of the positive electrode sheet. First, a plurality of first insulating materials on a slurry to be spacers are applied to the surface of the current collecting foil on the film in a second direction perpendicular to the first direction in which the current collecting foil travels (spacer material application). The first insulating material is produced by kneading and combining various materials as raw materials.

Subsequently, on the surface of the current collecting foil on the film, the negative electrode material on the slurry is applied between the first insulating materials which are applied apart from each other in the second direction (negative electrode material application). The negative electrode material is produced by kneading and combining various materials as raw materials.

Subsequently, a second insulating material in a slurry form to be a separator is applied (separator material application) to the upper surface of the first insulating material and the negative electrode material formed on the surface of the current collecting foil on the film. The second insulating material is produced by kneading and combining various materials as raw materials.

Subsequently, the entire coating film obtained by laminating the negative electrode material and the first insulating material coated on the surface of the current collecting foil on the film and the second insulating material coated on the upper surface thereof was dried (dried), and then the current collector foil And processing of cutting is performed (processing). Thus, a film-like negative electrode sheet in which a negative electrode made of a negative electrode material, a spacer made of a first insulating material, and a separator made of a second insulating material formed on the upper surface thereof are laminated is produced on the surface of the current collecting foil on the film. When the current collecting foil on which the coating film is formed is cut, 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 of a required size is cut out from the film-shaped positive electrode sheet, a negative electrode of a required size is cut out from the negative electrode sheet on the film, and the positive electrode and the negative electrode are stacked (Circulation). Since the separator is already formed in the positive electrode sheet and the negative electrode sheet, in this winding step, it is not necessary to wind the separator between the positive electrode and the negative electrode to overlap each other and reduce the manufacturing cost.

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.

<< Materials of lithium ion battery >>

The lithium-containing complex oxide having a spinel structure containing, for example, lithium cobalt oxide or Mn (manganese) can be used as the cathode active material used in the first embodiment. The positive electrode active material may also be a composite oxide containing Ni (nickel), Co (cobalt) and Mn (manganese), or an olivine-type compound represented by olivine-type phosphate. However, the material used for the positive electrode active material is not limited thereto.

Since the lithium-containing composite oxide having a spinel structure containing Mn (manganese) has excellent thermal stability, a lithium ion battery having high stability can be constituted by forming a positive electrode sheet containing the same. In addition, as the positive electrode active material, only a lithium-containing complex oxide having a spinel structure containing Mn (manganese) may be used, but other positive electrode active materials may be used in combination. Examples of other such cathode active materials include olivine-type compounds represented _by Li _{1 + x} MO ₂ (-0.1 <x <0.1, M: Co, Ni, Mn, Al, Mg, Zr, have. Specific examples of the layered lithium-containing transition metal oxide include LiCoO ₂ or LiNi _{1 - x} Co _{x -y} Al _y O ₂ (0.1? _X ? 0.3, 0.01? _Y ? 0.2) In addition, the lithium-containing transition metal oxide of a layered structure, at least a Ni (nickel), Co (cobalt), and Mn (manganese) oxide _{(LiMn 1/3 Ni 1/3 Co 1/3 O} 2, LiMn containing _{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, graphite materials such as natural graphite (flake graphite), artificial graphite or expanded graphite can be used. As the negative electrode active material, a graphitizable carbonaceous material such as coke obtained by baking the pitch may be used. As the negative electrode active material, a non-graphitizable carbonaceous material such as amorphous carbon obtained by low-temperature firing of furfuryl alcohol resin (PFA), polyparaphenylene (PPP) or phenol resin may be used. 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 lithium alloys such as Li-Al, alloys containing elements capable of alloying Si (silicon), Sn (tin), and Li (lithium). It is also possible to use oxide-based materials such as Sn oxide or Si oxide.

The conductive auxiliary agent used in the present example 1 is used as an electronic conduction assisting agent contained in the anode film and is preferably a carbon material such as carbon black, acetylene black, ketjen black, graphite, carbon fiber or carbon nanotube Do. Among the above-mentioned carbon materials, acetylene black or ketjen black is particularly preferable from the viewpoint of the addition amount and the effect of conductivity, and the productivity of the positive electrode material mixture slurry for application. The conductive auxiliary agent may be contained in the negative electrode film, and may be preferable.

It is preferable that the binder used in the first embodiment also contains a binder for binding the active material and the conductive auxiliary agent. 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. These polymers may be used in combination of two or more. The binder is preferably used in the form of a solution dissolved in a solvent.

As the fluorine-containing monomer group for synthesizing the polyvinylidene fluoride-based polymer, vinylidene fluoride or a mixture of vinylidene fluoride and another monomer, a monomer mixture containing 80% by mass or more of vinylidene fluoride . 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.

The content of the binder in the electrode film is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and 10 mass% or less and still more preferably 5 mass% or less based on the dried electrode film. If the content of the binder is too small, not only the solidification in the drying step becomes insufficient, but also the mechanical strength of the electrode film after drying becomes insufficient and the electrode film may peel off from the current collecting foil. If the content of the binder is too large, the amount of the active material in the electrode film may decrease and the battery capacity may decrease.

As the insulating material used in the first embodiment, 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 mixed can be used, and by using the slurry, a shredded property can be obtained. In order to bind the inorganic oxide particles used for the insulating material, a resin is used as a binder. As the binder, a binder used for the electrode film is preferably used.

The current collecting foil used in this embodiment is not limited to a sheet-like foil. As the base material, a pure metal such as Al (aluminum), Cu (copper), stainless steel or Ti (titanium), or an alloy conductive material may be used and the shape thereof may be a net, a punched metal, And the like are used. The thickness of the current collector foil is selected, for example, from 5 탆 to 30 탆, more preferably from 8 탆 to 16 탆. The thickness of the electrode film formed on one surface (surface) of the current collector foil is, for example, about 50 mu m to 400 mu m after drying.

The lithium ion battery in the first embodiment can be manufactured in the same manner as a conventional lithium ion battery except that it includes a positive electrode and a negative electrode manufactured by the above-described method. The structure or size of the battery container or the structure of the electrode body having the positive electrode and the negative electrode as the main constituent elements is not particularly limited.

As described above, according to the first embodiment, even if the electrode material to be the electrode film is applied to the surface of the current collecting foil (PEP) thickly, 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 collecting foil (PEP). In addition, even if the electrode material is coated thickly and the second insulating material IF2 serving as the separator SE is thinly coated, the film breakage of the second insulating material IF2 does not occur, so that the second insulating material IF2 is thin And uniformly applied. This makes it possible to reduce the thickness of the separator SE and the thickness of the electrode film without deteriorating the production yield of the lithium ion battery.

(Example 2)

What is different from the first embodiment described above is a process order of a step of applying a first insulating material to be a spacer and a step of applying an electrode material to be an electrode film. That is, in Embodiment 1 described above, the first insulating material IF1 is applied to the surface of the current collecting foil (PEP) and then the cathode material (PAS) is applied to the surface of the current collecting foil (PEP) The cathode material PAS is applied to the surface of the current collecting foil PEP and then the first insulating material IF1 is applied to the surface of the current collecting foil PEP.

&Lt; Production method of electrode sheet of lithium ion battery &gt;

A method of manufacturing an electrode sheet of a lithium ion battery in the second embodiment will be described with reference to Figs. 4 and 5. Fig. 4 is a schematic view of an apparatus for manufacturing an electrode sheet of 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 for producing the electrode sheet of the lithium ion battery in the second embodiment. Fig. Fig. 5A is a cross-sectional view (A2-A2 sectional view in Fig. 4) of the electrode sheet in the electrode material application step, Fig. 5B is a cross- Sectional view of the electrode sheet in the second insulating material (separator material) application step (C2-C2 sectional view in Fig. 4). 5 (d) is a cross-sectional view (D2-D2 sectional view in Fig. 4) of the electrode sheet in the drying step.

In the second embodiment, a method of manufacturing a positive electrode film formed in one row on the surface of the current collecting foil along the first direction in which the current collecting foil travels is exemplified. In the second embodiment, the manufacturing method of one side of the positive electrode sheet is exemplified, but the manufacturing method of the one side of the negative electrode sheet is also the same.

4, in the electrode sheet producing apparatus M2, the current collecting foil PEP is fed from the take-up roll SL1 and is fed from the first roller RL1, the second roller RL2, And is conveyed to the winding roll SL2 by the fourth roller RL3, the fourth roller RL4, the fifth roller RL5, the sixth roller RL6 and the seventh roller RL7. A first slit die coater DC1 is provided so as to face the third roller RL3 and a dispenser DP is provided so as to face the fourth roller RL4 and a second slit die coater DC1 is provided opposite to the fifth roller RL5, A die coater DC2 is provided.

1. First coating step (electrode material coating step)

First, a slurry-like cathode material PAS supplied from a first slit die coater DC1 at a position opposed to the third roller RL3 is coated on the surface of the current collecting foil PEP sent out from the take-up roll SL1 do. The cathode material PAS is stored in the tank TA1 and supplied to the surface of the current collecting foil PEP by the metering pump PU1.

As shown in Fig. 5 (a), the cathode material PAS is applied to the surface of the current collecting 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 collecting foil PEP sent out from the winding roll SL1 . The first insulating material IF1 is stored in the tank TA2 and supplied to the surface of the current collecting foil PEP by the metering pump PU2.

5B, a plurality of first insulating materials IF1 are laminated on a surface of a current collecting foil PEP running in a first direction, a current collecting foil (PEP) in the first coating step, (PAS) applied on the surface of the current collector (PAS) in a first direction and in a second direction orthogonal to the surface of the current collecting foil (PEP). In other words, the first insulating material IF1 contacts both side surfaces of the cathode material PAS in the second direction and is applied to the surface of the current collecting foil PEP outside the cathode material PAS in the second direction.

The thickness of the first insulating material IF1 is substantially equal to the thickness of the cathode material PAS. Although the thickness of the cathode material PAS and the thickness of the first insulating material IF1 are preferably the same as in the first embodiment described above, the anode material PAS is applied on the top surface of the first insulating material IF1 The first insulating material IF1 is applied so that the upper surface of the anode material PAS becomes 0 占 퐉 to 10 占 퐉 lower than the upper surface of the first insulating material IF1. The region to which the first insulating material IF1 is applied is a region where the anode sheet is cut off after completion.

The dispenser DP is advantageous in that the position adjustment is easier than the first slit die coater DC1 as a feature of this mechanism. For example, as in the first embodiment, when the cathode material (PAS) is applied after the first insulating material IF1 is applied, the position of the first slit die coater DC1 is shifted, There is a possibility that the cathode material (PAS) is applied on the upper surface of the substrate (IF1). However, in the second embodiment, since the first insulating material IF1 is applied using the dispenser DP which is easily aligned after the cathode material PAS is applied, And the anode material (PAS) can be eliminated. However, if the thickness of the positive electrode material (PAS) is made thick, the side surface of the positive electrode material (PAS) is inclined, so that the thickness of the positive electrode material (PAS) can not be made thick as in the case of the first embodiment.

3. Third Coating Process (Second Insulating Material (Separator Material) Coating Process)

Next, as in the third coating step (the second insulating material (separator material) coating step) of the first embodiment described above, the second slit die coater DC2 is supplied from the second slit die coater DC2 at a position facing the fifth roller RL5 The second insulating material IF2 in slurry is applied. The second insulating material IF2 is stored in the tank TA3 and supplied to the upper surface of the first insulating material IF1 and the cathode material PAS by the metering pump PU3.

The second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS along the first direction in which the current collecting foil PEP travels, as shown in Fig. 5 (c) do. The thickness of the second insulating material IF2 is, for example, about 5 mu m to 40 mu m. The thickness of the second insulating material IF2 is adjusted by adjusting the height of the mouthpiece D1 of the second slit die coater DC2 (see FIG. 10) and the amount of the second insulating material IF2 .

The second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS which are substantially planar surfaces and the first insulating material IF1 and the anode material PAS are coated, Is not applied to the side of the material (PAS) and the surface of the current collecting foil (PEP) to which the first insulating material (IF1) and the cathode material (PAS) are not applied. Therefore, the second insulating material IF2 can be uniformly applied, and thus the film breakage of the second insulating material IF2 can be prevented.

4. Drying process

Next, in the same manner as in the drying step of Embodiment 1 described above, the positive electrode material (PAS) applied to the surface of the current collecting foil (PEP) and the first insulating material (IF1 And a second insulating material IF2 coated on the upper surface thereof are dried, and a current collecting foil PEP, on which a cathode film and a separator are formed, is wound around a winding roll SL2.

5 (d), the thickness of the cathode material PAS and the thickness of the first insulating material IF1 were almost the same before drying, but after drying, the thickness of the solid material contained in the cathode material PAS The thickness of the spacer SP made of the first insulating material IF1 is smaller than the thickness of the anode film PE made of the cathode material PAS because of the difference in the amount of the solid material contained in the first insulating material IF1 Thin.

In the second embodiment, a method of manufacturing the positive electrode film (PE) formed in one row on the surface of the current collecting foil (PEP) along the first direction in which the current collecting foil PEP travels is exemplified, but the present invention is not limited thereto . For example, the number of the anode films (PE) may be two or more, and the same effect can be obtained.

As described above, according to the second embodiment, misalignment between the first insulating material IF1 and the electrode material is eliminated. Since the film breakage of the second insulating material IF2 does not occur even if the second insulating material IF2 serving as the separator SE is thinly coated, the second insulating material IF2 can be thinly and uniformly coated have. This makes it possible to reduce the thickness of the separator SE without reducing the production yield of the lithium ion battery.

(Example 3)

What is different from the above-described first embodiment is the number of steps of applying the electrode material. That is, in Embodiment 1 described above, the cathode material (PAS) is applied to the surface of the current collecting foil (PEP) by one coating process, but in Embodiment 3, the cathode material (PAS) (PEP).

&Lt; Production method of electrode sheet of lithium ion battery &gt;

A method of manufacturing an electrode sheet of a lithium ion battery according to the third embodiment will be described with reference to Figs. 6 and 7. Fig. 6 is a schematic view of an apparatus for manufacturing an electrode sheet of a lithium ion battery according to the third embodiment. 7 is a cross-sectional view of an electrode sheet in each coating step and drying step for explaining a method for producing an electrode sheet of a lithium ion battery in the third embodiment. Fig. 7A is a cross-sectional view (A3-A3 sectional view in Fig. 6) of the electrode sheet in the first insulating material (spacer material) coating process, Fig. 7B is a cross- 6 is a cross-sectional view taken along a line B3-B3 in Fig. 6) and Fig. 7 (c) is a cross-sectional view (a cross-sectional view taken along line C3-C3 in Fig. 6) of the electrode sheet in the second electrode material application process. 6 (D3-D3 sectional view in Fig. 6) and Fig. 7 (e) is a sectional view of the electrode sheet in the drying step (Fig. 6 E3-E3 sectional view).

In the third embodiment, a method of manufacturing the positive electrode film formed in two rows on the surface of the current collecting foil along the first direction in which the current collecting foil travels is exemplified. In the third embodiment, the manufacturing method of the one surface of the anode sheet is exemplified, but the manufacturing method of the one surface of the anode sheet is also the same.

6, in the electrode sheet producing apparatus M3, the current collecting foil PEP is fed from the take-up roll SL1 and passes through the first roller RL1, the second roller RL2, And is conveyed to the winding roll SL2 by the fourth roller RL3, the fourth roller RL4, the fifth roller RL5, the sixth roller RL6, the seventh roller RL7 and the eighth roller RL8. A first slit die coater DC1 is provided so as to face the fourth roller RL4 and a second slit die coater DC1 is provided so as to face the fifth roller RL5, A die coater DC2 is provided, and a third slit die coater DC3 is provided so as to face the sixth roller RL6.

1. First coating step (first insulating material (spacer material) coating step)

First, the first insulating material IF1 is applied to the surface of the current collecting foil (PEP) in the same manner as the coating step (the first insulating material (separator material) coating step) of the first embodiment described above.

As shown in Fig. 7A, a plurality of first insulating materials IF1 are formed on the surface of a current collecting foil PEP running in the first direction, in a direction perpendicular to the first direction and on the surface of the current collecting foil (PEP) In the second direction. That is, the plurality of first insulating materials IF1 are formed in such a manner that a region in which the cathode material PAS is applied to the surface of the current collecting foil PEP running in the first direction in the subsequent second and third coating processes, (PEP) in the direction of the surface of the current collecting foil (PEP). In other words, the plurality of first insulating materials IF1 are arranged in the second direction (the first direction) of the region of the cathode material (PAS) applied to the surface of the current collecting foil (PEP) running in the first direction in the subsequent second and third coating processes As shown in FIG. In the third embodiment, a plurality of first insulating materials IF1 are separated from each other in the second direction so as to form two rows of positive electrode films along the first direction on the surface of the current collecting foil (PEP) ) Along the first direction.

The thickness of the first insulating material IF1 is substantially equal to the thickness of the cathode material PAS applied to the surface of the current collecting foil PEP in the subsequent second and third coating processes. Since the region to which the first insulating material IF1 is to be applied is a region to be cut after the cathode sheet is completed, the width of the first insulating material IF1 in the second direction is set small to suppress the material cost. For example, in consideration of the width required for cutting, the width of the first insulating material IF1 in the second direction is about 5 to 15 mm.

2. Second coating step (first electrode material coating step)

Next, on the surface of the current collecting foil PEP sent out from the take-up roll SL1, a slurry-like first cathode material PAS1 supplied from the first slit die coater DC1 at a position opposed to the fourth roller RL4 ) Is applied. The first cathode material PAS1 is stored in the tank TA2 and supplied to the surface of the current collecting foil PEP by the metering pump PU2.

As shown in Fig. 7 (b), a plurality of first cathode materials PAS1 are formed on the surface of the current collecting foil PEP running in the first direction and the current collecting foil PEP in the first coating step, Is applied to a region sandwiched between the first insulating material IF1 applied to the surface of the first insulating material IF1. In the third embodiment, a plurality of first cathode materials PAS1 are separated by a first insulating material IF1 so as to form two rows of anode films along the first direction on the surface of the current collecting foil PEP Are separated from each other in two directions, and two rows are applied to the surface of the current collecting foil (PEP) along the first direction.

The thickness of the first cathode material PAS1 is thinner than the thickness of the first insulating material IF1 applied to the surface of the current collecting foil PEP in the first coating step. That is, the upper surface of the first cathode material PAS1 is located lower than the upper surface of the first insulating material IF1. The thickness of the first anode material PAS1 is adjusted by adjusting the height of the mouthpiece D1 of the first slit die coater DC1 (see FIG. 10) and the amount of the first cathode material PAS1 .

3. Third coating process (second electrode material coating process)

Next, on the surface of the current collecting foil PEP sent out from the take-up roll SL1, the slurry-like second cathode material PAS2 supplied from the second slit die coater DC2 at a position opposed to the fifth roller RL5 ) Is applied. The second cathode material PAS2 is stored in the tank TA3 and supplied to the upper surface of the first cathode material PAS1 by the metering pump PU3. Here, the binder content of the second cathode material (PAS2) is smaller than the binder content of the first cathode material (PAS1).

7 (c), the second cathode material PAS2 is applied to the upper surface of the first cathode material PAS1, and the first cathode material PAS1 and the second cathode material PAS2 are laminated on the upper surface of the first cathode material PAS1, The cathode material (PAS) is formed.

The height from the surface of the current collecting foil PEP to the top surface of the cathode material PAS and the height from the surface of the current collecting foil PEP to the top surface of the first insulating material IF1 are substantially the same, PAS2) is applied. That is, the thickness of the cathode material (PAS) becomes substantially equal to the thickness of the first insulating material IF1 applied to the surface of the current collecting foil (PEP) in the first coating step. It is preferable that the thickness of the cathode material PAS and the thickness of the first insulating material IF1 are equal to each other. However, in order to prevent the second cathode material PAS2 from being applied to the upper surface of the first insulating material IF1, The second cathode material PAS2 is applied so that the upper surface of the first insulating material PAS becomes lower by about 0 mu m to 10 mu m than the upper surface of the first insulating material IF1. The thickness of the second anode material PAS2 is adjusted by adjusting the height of the mouthpiece D1 of the second slit die coater DC2 (see Fig. 10) and the amount of the second cathode material PAS2 .

In the third embodiment, the cathode material (PAS) is formed by laminating the first cathode material (PAS1) and the second cathode material (PAS2) having different binder contents. This is for the following reasons.

First, a problem in the case of constituting the cathode material (PAS) by a single layer will be described. The positive electrode material (PAS) in the form of a slurry contains, in addition to the active material and the conductive auxiliary agent, a binder for binding the active material and the conductive auxiliary agent. However, this binder tends to be segregated on the upper surface side of the cathode material (PAS) in the drying step, and when the content of the binder is too small, this causes the binder to be present at the interface between the current collector foil (PEP) and the cathode material The cathode material (PAS) can be peeled off. Particularly, when the positive electrode material (PAS) is thickly coated, the segregation of the binder becomes remarkable, so that 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 cathode material (PAS), segregation of the binder can be made less likely to occur. However, if the content of the binder is too large, the amount of the active material decreases and the capacity of the battery is lowered, or the binder is hard to be mixed. Therefore, there is a balance between the viscosity and the surface tension of the cathode material (PAS), and it is difficult to adjust the content of the binder contained in the cathode material (PAS) to an optimum content. Particularly, , It becomes difficult to adjust the content of the binder.

However, in Embodiment 3, a first cathode material (PAS1) having a relatively large binder content is applied, and a second cathode material (PAS2) having a relatively small binder content is coated thereon. In the drying process, the first cathode material PAS1 and the second cathode material PAS2 are mixed with each other, but the cathode material PAS is formed by two layers of the first cathode material PAS1 and the second cathode material PAS2 The binder segregation on the upper surface side of the cathode material PAS is smaller than that in the case where the anode material PAS is applied as a single layer. Thus, in Embodiment 3, the peeling of the cathode material PAS is prevented can do.

In order to set the optimum binder content, for example, the first cathode material (PAS1) and the second cathode material (PAS2) having a viscosity and a surface tension so that the side faces of the first cathode material (PAS1) and the second cathode material It may be necessary to use the cathode material (PAS2). However, even in such a case, in the third embodiment, since the region to which the first cathode material PAS1 and the second cathode material PAS2 are to be applied is previously defined by the first insulating material IF1, The shapes of the first anode material PAS1 and the second anode material PAS2 are stable.

4. Fourth application step (second insulation material (separator material) application step)

Next, as in the case of the third coating step (the second insulating material (separator material) coating step) of the first embodiment described above, the third slit die coater DC3, which is opposed to the sixth roller RL6, The second insulating material IF2 in slurry is applied. The second insulating material IF2 is stored in the tank TA4 and supplied to the upper surface of the first insulating material IF1 and the second cathode material PAS2 by the metering pump PU4.

The second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS along the first direction in which the current collecting foil PEP travels, as shown in Fig. 7 (d) do. The thickness of the second insulating material IF2 is, for example, about 5 mu m to 40 mu m. The thickness of the second insulating material IF2 is adjusted by adjusting the height of the mouthpiece D1 of the third slit die coater DC3 (see FIG. 10) and the amount of the second insulating material IF2 .

The second insulating material IF2 is applied to the upper surface of the first insulating material IF1 and the cathode material PAS which are substantially planar surfaces and the first insulating material IF1 and the anode material PAS are coated, Is not applied to the side of the material (PAS) and the surface of the current collecting foil (PEP) to which the first insulating material (IF1) and the cathode material (PAS) are not applied. Therefore, the second insulating material IF2 can be uniformly applied, and thus the film breakage of the second insulating material IF2 can be prevented.

5. Drying process

Next, in the same manner as in the drying step of Embodiment 1 described above, the positive electrode material (PAS) applied to the surface of the current collecting foil (PEP) and the first insulating material (IF1 And a second insulating material IF2 coated on the upper surface thereof are dried, and a current collecting foil PEP, on which a cathode film and a separator are formed, is wound around a winding roll SL2.

As shown in Fig. 7 (e), the first cathode material PAS1 and the second cathode material PAS2 are mixed with each other to form a single-layer cathode material (PAS). Before the drying, the thickness of the cathode material (PAS) and the thickness of the first insulating material (IF1) were almost the same. However, after drying, the solid material contained in the first cathode material PAS1 and the second cathode material PAS2 The thickness of the spacer SP made of the first insulating material IF1 is smaller 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 first insulating material IF1 and the amount of the solid matter contained in the first insulating material IF1 .

On the other hand, in the third embodiment, a manufacturing method of the anode film (PE) formed in two rows on the surface of the current collecting foil (PEP) along the first direction in which the current collecting foil PEP travels is exemplified, . For example, the anode film (PE) may be one column or three or more columns, and the same effect can be obtained.

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

As described above, according to the third embodiment, by forming the cathode material PAS by laminating the first cathode material PAS1 and the second cathode material PAS2, the segregation of the binder on the upper surface side of the cathode material PAS is reduced Thus, peeling of the cathode material (PAS) can be prevented. Since the regions to which the first cathode material PAS1 and the second cathode material PAS2 are to be applied are defined in advance by the first insulating material IF1, the first cathode material PAS1 and the second cathode material PAS2 Is stable. In addition, even if the second insulating material IF2 serving as the separator SE is thinly coated, film breakage of the second insulating material IF2 does not occur, so that the second insulating material IF2 can be applied thinly and uniformly . This makes it possible to reduce the thickness of the separator SE and the thickness of the electrode film without deteriorating the production yield of the lithium ion battery.

Although the present invention has been described in detail based on the embodiments thereof, it is needless to say that the present invention is not limited to the above-described embodiments, but may be variously changed without departing from the gist of the present invention.

D1: Corner
D2: Manifold
D3:
D4: Agglomerate of electrode material
D5: downstream meniscus (bending of liquid surface)
D6: downstream side lips
DC1: first slit die coater
DC2: second slit die coater
DC3: third slit die coater
DP: dispenser
DRY: Drying furnace
h1: First interval
IF: Insulation material
IF1: first insulating material
IF2: Second insulating material
M1: electrode sheet manufacturing apparatus
M2: Electrode sheet manufacturing apparatus
M3: Electrode sheet manufacturing equipment
PAS: anode material
PAS1: First cathode material
PAS2: Second cathode material
PE: anode film
PEP:
PU1, PU2, PU3, PU4: metering pump
RL1: First roller
RL2: second roller
RL3: Third roller
RL4: fourth roller
RL5: fifth roller
RL6: sixth roller
RL7: seventh roller
RL8: Eighth roller
SE: Separator
SL1: withdrawal
SL2: winding roll
SP: Spacer
TA1, TA2, TA3, TA4: tank

Claims (12)

delete delete delete delete delete delete (a) applying a plurality of slurry-like first insulating materials on the surface of a current collecting foil running in a first direction, the first insulating material being spaced apart from each other in the first direction and in a second direction orthogonal to the current collecting foil surface,
(b) a step of applying a slurry-like electrode material to the surface of the current collecting foil sandwiched between the first insulating materials adjacent to each other in the second direction after the step (a)
(c) a step of applying a slurry-like second insulating material to the upper surface of the electrode material and the first insulating material after the step (b)
(d) after the step (c), drying the electrode material, the first insulating material and the second insulating material,
Wherein the amount of the solid material contained in the first insulating material is smaller than the amount of the solid material contained in the electrode material so that the thickness of the first insulating material after the drying step becomes thinner than the thickness of the electrode material. Way. (a) a step of applying a slurry-like electrode material to a current collecting foil surface running in a first direction,
(b) applying a slurry-like first insulating material to the surface of the current collecting foil on both sides of the electrode material in the first direction and in a second direction orthogonal to the surface of the current collecting foil after the step (a)
(c) a step of applying a slurry-like second insulating material to the upper surface of the electrode material and the first insulating material after the step (b)
(d) after the step (c), drying the electrode material, the first insulating material and the second insulating material,
Wherein the amount of the solid material contained in the first insulating material is smaller than the amount of the solid material contained in the electrode material so that the thickness of the first insulating material after the drying step becomes thinner than the thickness of the electrode material. Way. The method of manufacturing a power storage device according to claim 7, wherein a plurality of electrode materials having different binder contents are stacked in the step (b). The method of manufacturing a power storage device according to claim 7 or 8, wherein a width of the first insulating material in the second direction is about 5 mm to 15 mm. The method according to claim 7 or 8, wherein in the step (b), the upper surface of the electrode material is 0 탆 to 10 탆 lower than the upper surface of the first insulating material. The method of manufacturing a power storage device according to claim 7 or 8, wherein the thickness of the second insulating material applied in the step (c) is 5 占 퐉 to 40 占 퐉.

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