KR101660189B1 - Method and device for manufacturing lithium-ion secondary battery - Google Patents

Abstract

When an insulating material serving as a separator is coated with a slit die coater after applying an electrode of a lithium ion secondary battery, a mixed layer is formed at the interface between the electrode material and the insulating material. Therefore, as the insulating material becomes thinner, The risk of failure increases. As a means for solving this problem, an electrode material supplied by a slit die coater is applied to an electrode substrate supplied at a predetermined speed, an insulating material is coated on the electrode material layer above the electrode substrate by a curtain coater, And drying and fixing layers of both materials in a drying furnace to produce an electrode sheet.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lithium ion secondary battery,

The present invention relates to a method and an apparatus for manufacturing a lithium ion secondary battery, and more particularly to a method and apparatus for manufacturing a lithium ion secondary battery including a positive electrode, a negative electrode, and a separator for electrically separating the positive electrode and the negative electrode.

BACKGROUND ART [0002] With the development of portable electronic devices, small secondary batteries capable of being repeatedly charged are used as power sources for these portable electronic devices. Among them, a lithium ion secondary battery having a high energy density, a long cycle life, a low self-discharge property, and a high operating voltage has attracted attention. Since the lithium ion secondary battery has the advantages described above, it has been widely used in portable electronic devices such as a digital camera, a notebook type personal computer, and a mobile phone. In recent years, research and development of a large-sized lithium ion secondary battery capable of realizing a high capacity, a high output, and a high energy density as an electric vehicle battery and a power storage battery are underway. Particularly, in the automobile industry, in order to cope with environmental problems, development of an electric vehicle using a motor as a power source or a hybrid vehicle using both an engine (internal combustion engine) and a motor as a power source is progressing. Lithium ion secondary batteries have attracted attention as power sources for such electric vehicles and hybrid cars. However, since the lithium ion secondary battery has a high operating voltage and a high energy density, sufficient measures against abnormal heat generation due to an internal short circuit or an external short circuit are required.

As shown in Fig. 8, the lithium ion secondary battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which lithium ions in the electrolyte take charge of electric conduction. A lithium metal oxide is used for the positive electrode material (active material), a carbon material such as graphite is used for the negative electrode material (active material), and an electrolyte such as an organic solvent such as ethylene carbonate and lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) Is used as the mainstream. In the battery, lithium ions enter the negative electrode from the positive electrode during charging, and conversely, during discharging, lithium ions enter the positive electrode out of the negative electrode.

The structure of the lithium ion secondary battery is a structure in which a positive electrode plate coated with a positive electrode material, a negative electrode plate coated with a negative electrode material, a separator such as a polymer film for preventing contact between the positive electrode plate and the negative electrode, And a winding body. In the lithium ion secondary battery, the electrode winding body is inserted into the outer can and the electrolyte is injected into the outer can. That is, in the lithium ion secondary battery, a positive electrode plate in which a positive electrode material is applied to a metal foil and a negative electrode plate in which a negative electrode material is applied to the metal foil are formed in a strip shape, and the positive electrode plate and the negative electrode plate So as to form an electrode winding body.

Japanese Patent Application Laid-Open No. 2003-045491 (Patent Document 1) discloses a positive electrode film and a negative electrode film which are separately formed, a separator film is bonded to the negative electrode film, It is very difficult to uniformly inject the electrolytic substance in a solution state into the current collector in which a plurality of the electrode winding bodies are stacked in the conventional electrode manufacturing method wherein the positive electrode film is laminated to form the electrode winding body, Discloses a technique for improving many defective products.

Japanese Patent Application Laid-Open No. 2003-045491 (Patent Document 1) discloses a technique of applying a positive electrode material-containing solution, an electrolytic solution, and an insulating material-containing solution on both surfaces of a positive electrode sheet material using a die coater having a slit for solution discharge A solution containing a negative electrode electrode material and a solution containing an insulating material are applied to both surfaces of the negative electrode sheet material by using a die coater, Discloses a method of manufacturing a secondary battery and an apparatus for manufacturing a secondary battery, in which an electrode sheet-like material is formed, and both electrode sheet-shaped materials are laminated to form an electrode winding.

Japanese Patent Application Laid-Open No. 2003-045491

In the application of the electrode material of the lithium ion secondary battery, after application of a positive electrode material or a negative electrode material to the surface of the carrier material as in Patent Document 1, an insulating material serving as a separator is applied to improve the production efficiency, It is possible to reduce the size of the apparatus.

However, when the electrode material of the positive electrode or the negative electrode is applied to the surface of the carrier material and then the insulating material to be the separator is coated by the slit die coater, the electrode material and the insulating material As the mixed layer is formed and the layer of the insulating material functioning as the separator becomes thin, the short circuit between the positive electrode and the negative electrode tends to occur, thereby increasing the risk of failure.

Accordingly, it is an object of the present invention to provide a method and apparatus for manufacturing a lithium ion secondary battery capable of thinning a mixed layer formed at an interface between an electrode material layer and an insulating material layer.

According to the present invention, there is provided a method of manufacturing a lithium ion secondary battery including a positive electrode, a negative electrode, and a separator for electrically separating a positive electrode and a negative electrode, An electrode material is coated and applied, and an insulating material is coated on the electrode material layer on the electrode substrate by a curtain coater on the downstream side thereof, and then a layer of both materials is dried and fixed in a drying furnace to produce an electrode sheet .

According to another aspect of the present invention, there is provided an electrode substrate feeder for feeding an electrode substrate at a predetermined speed, first, second, and third rollers for feeding the electrode substrate at a predetermined speed, A slit die coater for applying an electrode material to the electrode substrate from a position opposing the slit die coater, and a slit die coater disposed downstream of the slit die coater, A drying furnace for heating and drying a layer of an electrode material and an insulating material applied on the electrode substrate on the downstream side of the curtain coater; And a winding roll for winding the electrode substrate. The apparatus for manufacturing a lithium ion secondary battery according to claim 1,

According to the present invention, when an electrode sheet production method in which an electrode material and an insulating material are overlapped and coated on a surface of a carrier material and dried and fixed at the same time is employed, generation of a mixed layer at the interface between the electrode material layer and the insulating material layer is suppressed Therefore, even when the insulating material is thinned, the short circuit between the positive electrode and the negative electrode is reduced, and the risk of failure is lowered.

The problems, the constitution, and the effects other than the above are clarified by the description of the embodiments described below.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram of a manufacturing process of a lithium ion secondary battery in Example 1. FIG.
Fig. 2 is a configuration diagram of a manufacturing process of a lithium ion secondary battery in a comparative example of the present invention.
3 is a conceptual diagram of a cross section of an interface between an electrode material layer and an insulating material layer in a slurry state coated on a carrier material.
4 is a graph showing the relationship between the insulating layer film thickness and the mixed layer film thickness in the die coating method of Example 1 and the comparative example.
5 is a configuration diagram of a manufacturing process of a lithium ion secondary battery in Example 2. Fig.
6 is a graph showing the relationship between the insulating layer film thickness and the mixed layer film thickness in the die coating method of Example 2 and the comparative example.
FIG. 7A is a cross-sectional view schematically showing a state of application by a slit die coater, and FIG. 7B is a cross-sectional view schematically showing a state of application by a curtain coater.
8 is a view for explaining the operation principle of the lithium ion secondary battery.
9 is a diagram schematically showing a specific process up to the production of the lithium ion secondary battery.

Hereinafter, embodiments will be described with reference to the drawings.

Fig. 9 is a diagram schematically showing a specific process up to the production of a lithium ion secondary battery. As shown in Fig. 9, the manufacturing process of the lithium ion secondary battery includes a positive electrode sheet manufacturing process, a negative electrode sheet manufacturing process, a battery cell assembling process, and a battery module assembling process.

In the positive electrode sheet production process, various materials serving as raw materials for the positive electrode material are first kneaded and combined to prepare a slurry material (positive electrode material). Then, the slurry material is applied to the film-shaped metal foil and dried, and the metallic foil coated with the slurry material is subjected to processing such as compression and cutting to produce a film-shaped positive electrode sheet.

On the other hand, in the process of manufacturing the negative electrode sheet, the various materials used as raw materials for use in the positive electrode sheet production process are different, but the procedure is the same until the negative electrode sheet is produced. First, a slurry material (negative electrode material) is prepared (kneaded and combined) by kneading and combining various materials as a raw material of the negative electrode material, and the slurry material is applied to the film-like metal foil and dried (applied) (Processing) such as compression or cutting of a metal foil coated with a material to produce a negative electrode sheet in film form.

Thereafter, in the process of assembling the battery cell, a positive electrode and a negative electrode of a required size are cut out from the film-like positive electrode sheet and the negative electrode sheet in a process called winding, and the positive electrode sheet and the negative electrode A separator of a required size is cut out from the separator material for separating the electrode sheet from the film-like separator material, and the separator is rolled up (wound) over the separator between the positive electrode and the negative electrode with a cut separator interposed therebetween. Then, a group of positive electrode, negative electrode and separator electrode pairs are assembled and welded. Thereafter, the group of these electrode pairs welded is placed in a battery can which is filled with an electrolyte (liquid injection), and then the battery can is completely sealed (sealed) to prepare a battery cell.

In the battery cell inspecting process, the cells of the lithium ion secondary cell formed in the cell assembling process are repeatedly charged and discharged, and an inspection of the performance and reliability of the battery cell (for example, capacity and voltage of the battery cell, (Such as a current or a voltage of the battery). Thereby, the battery cell is completed, and the battery cell assembling process is completed.

Next, in the module assembling process, a plurality of battery cells are combined in series to constitute a battery module, and a charge / discharge controller is connected to manufacture a battery system (module assembly). Thereafter, in the module inspecting process, inspections regarding the performance and reliability of the assembled battery module in the module assembling process (for example, inspection of the capacity or voltage of the battery module, current or voltage at the time of charging or discharging) (Module inspection).

The present invention relates to a manufacturing method and a manufacturing apparatus relating to the positive electrode sheet production step and the application and coating step in the negative electrode sheet production step. According to the embodiment of the present invention, it is possible to omit the pouring step of injecting the electrolytic solution into the battery can in the battery cell assembling step.

Example 1

Fig. 2 is a block diagram of a series of manufacturing processes in which an electrode material, an electrolytic material, and an insulating material are successively applied to a positive electrode sheet material or a negative electrode sheet material disclosed in the second embodiment of Patent Document 1, followed by drying and fixing Respectively. In Patent Document 1, although electrode materials and electrolytic and insulating materials are applied to both sides of the carrier material (the shape of the positive electrode sheet or the shape of the negative electrode sheet), it is considered to be unrealistic. Therefore, as a comparative example of this embodiment, Material, and an electrolytic, insulating material.

In the manufacturing process of Fig. 2, one side of the positive electrode sheet is produced. The positive electrode plate PEP is coated with the positive electrode material PAS fed from the positive electrode plate feed roll 1 RL1 and supplied from the slit die coater 1 DC1 against the roller 2 RL2, The insulating material IF supplied from the slit die coater 2 (DC2) at a position opposed to the roller 3 (RL3) is applied, dried by passing through the drying furnace DRY and wound on the winding roll 5 (RL5) , A positive electrode sheet is produced.

The above-mentioned slit die coater 1 (DC1) has been widely adopted for thick film application and application of a high viscosity coating. In the die coating method of this comparative example, as shown by the separating member 71 in Fig. 7A, the positive electrode material (slurry material) (PAS) The cathode material (slurry material) PAS is supplied to the manifold 73 of the first member 71. Next, as shown in Fig. The positive electrode material (slurry material) PAS is supplied and discharged to the slit 74 formed in the separating member 71 after the pressure distribution of the positive electrode material in the manifold 73 is made uniform. The discharged positive electrode material (slurry material) PAS is maintained at relatively constant intervals h1 (h1 = 50 to 100 m in this comparative example and in this embodiment) with the separating member 71, A positive electrode material storage portion 75 called a bead is formed between the carrier material (the shape of the positive electrode sheet) 81 running on the carrier material (positive electrode sheet material) 81. In this state, And a coating film is formed.

Here, the coating film is continuously formed by supplying the positive electrode material of the same amount as that consumed by the coating film formation from the slit 74. It is important to stabilize the shape of the downstream meniscus (liquid surface bending) 79 of the positive electrode material reservoir portion 75 in order to stably apply the organic solvent-based thin film having a high evaporation rate. The pressure for supplying the positive electrode material to the manifold 73 is reduced by the pressure loss of the slit portion 74 + the pressure loss of the downstream side lip portion 78 of the crotch member 71 + the pressure of the downstream side meniscus 79 do.

In the manufacturing process of Fig. 2, the insulating material is applied by the second slit die coater 2 (DC2), and the die coating method therefor is the same as that of the slit die coater 1 (DC1) . A slurry material (insulating material IF) containing an electrolytic insulating material discharged from the slit 74 of the slit die coater 2 (DC2) as a raw material is used as a carrier material (positive electrode sheet material) 81 in the upstream direction, Coating is applied on top.

As described above, since the positive electrode material in the slurry state and the insulating material are overlapped and coated, the both coating layers can be simultaneously dried and fixed through the heating and drying process by the drying furnace DRY, and the efficiency is good. However, the positive electrode material and the insulating material in the slurry state applied on the carrier material have the electrode material layer (EL) coated on the carrier material (EP) of the electrode plate and the insulating material layer The mixed layer MIX in which the insulating function is lost is formed at the interface of the gate electrode SEL. The problem is that the thickness of the insulating material layer SEL having an insulating function becomes thinner than originally intended due to the generation of the mixed layer MIX.

In this embodiment, a die coating method capable of thinning the mixed layer at the interface between the electrode material layer and the insulating material layer, even when the insulating material layer serving as the separator is designed to be thin with the miniaturization of the lithium ion secondary battery .

Fig. 1 shows an example of the constitution of a manufacturing method of a lithium ion secondary battery of this embodiment.

The positive electrode material PAS supplied from the slit die coater DC1 against the roller 2 (RL2) is applied to the positive electrode plate PEP, and the roller 3 (RL3 The insulating material IF supplied from the curtain coater CC1 at a position opposed to the winding roller 5 is coated and dried and then dried by passing through the drying oven DRY and wound around the winding roll 5 (RL5) do. 2, the insulating material IF is supplied from the curtain coater CC1 instead of supplying the insulating material IF from the slit die coater 2 (DC2) Is applied and applied.

7B, the curtain coater CC1 discharges the insulating material (slurry material) IF (not shown) from the tank storing the insulating material (slurry material) IF, as shown by the claw member 72, The insulating material (slurry material) IF is supplied to the manifold 76 of the detaching member 72. [ The insulating material (slurry material) IF is supplied and discharged by the slit 77 formed in the separating member 72 after uniformizing the pressure distribution of the insulating material in the manifold 76. [ The discharged insulating material (slurry material) IF forms a curtain film 80 having a uniform and stable flow rate and falls. The curtain film 80 is held at a constant interval h2 from the separating member 72 (PAS) layer on the relatively moving carrier material (positive electrode sheet material) 81, and is uniformly applied and formed.

In this embodiment, the distance h2 between the curtain coater CC1 and the carrier material (the shape of the positive electrode sheet) 81 is set to 100 to 10 mm. Also in the curtain coater CC1, as in the slit die coater 1 (DC1) described above, the coating material is continuously formed by supplying the same amount of insulation material as that consumed by the coating film formation from the slit 77. [ Therefore, it is sufficient that the pressure for supplying the insulating material to the manifold 76 is a pressure that secures the pressure loss of the slit portion 77 and the flow amount equivalent to the amount consumed by the above-mentioned film formation. The insulating material (slurry material) (IF) injected through the slit 77, and the falling distance (h2) with initial velocity V _0,

Since the gap h2 is as small as described above, the velocity Vc is small, and the pressure in contact with the coating film of the positive electrode material on the carrier substrate is the same as that of the positive electrode of the slit die coater 1 (DC1) Is smaller than the pressure loss on the downstream side lip portion 78 of the cementing member 71 in the material storage portion 75 plus the pressure on the downstream side meniscus 79.

In the present embodiment, the positive electrode material (PAS) is prepared by mixing an active material containing lithium cobalt oxide and carbon as a conductive auxiliary agent, mixing a binder containing polyvinylidene fluoride (binder) with N-methylpyrrolidone Was used.

The insulating material IF was a slurry obtained by kneading a powder of silica (SiO ₂ ) into a solution in which a binder (polyvinylidene fluoride-containing binder) was dissolved in N-methylpyrrolidone (NMP).

In the evaluation of the mixed layer at the interface between the electrode material layer and the insulating material layer in the die coating method of this embodiment, the cross section of the completed electrode was cut out and the film thickness of the mixed layer was calculated from the image observed with SEM. Based on the conceptual diagram of the section shown in Fig. 3, the results of evaluation of the film thickness of the mixed layer MIX are summarized in Fig. In the comparative example, it was found that the film thickness of the mixed layer becomes larger as the film thickness of the insulating layer becomes thinner, and the possibility of occurrence of a short circuit becomes higher at the film thickness of the insulating film of 25 μm or less. As a result of the die coating method of this embodiment, it was found that even if the insulating layer had a small thickness, the film thickness of the mixed layer was 5 m or less, and the possibility of occurrence of a short circuit was low.

Example 2

Example 2 describes an example of a die coating method in which the risk of short circuiting is lowered even when the interface between the electrode material layer and the insulating material layer becomes uniform and the separator material becomes thinner.

Fig. 5 shows an example of the constitution of a manufacturing method of a lithium ion secondary battery of this embodiment.

The positive electrode plate PEP is coated with the positive electrode material PAS fed from the positive electrode plate feed roll RL1 and fed from the slit die coater DC1 against the roller 2 RL2, The coated film height is adjusted by the knife coater KC1 against the roller 6 (RL6), and the drying furnace DRY (DRY) , And is wound around a take-up roll 5 (RL5) to produce a positive electrode sheet.

The positive electrode material (PAS) is prepared by mixing an active material containing lithium cobalt oxide and carbon as a conductive auxiliary agent and kneading the mixture in a solution in which a binder (binder) containing polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) Slurry was used.

The insulating material IF was a slurry obtained by kneading a powder of silica (SiO ₂ ) into a solution in which a binder (polyvinylidene fluoride-containing binder) was dissolved in N-methylpyrrolidone (NMP).

In the evaluation of the mixed layer at the interface between the electrode material layer and the insulating material layer in the die coating method of this embodiment, the cross section of the completed electrode was cut out and the film thickness of the mixed layer was calculated from the image observed with SEM. The result of evaluating the film thickness of the mixed layer MIX based on the conceptual diagram of the section shown in Fig. 3 is summarized in Fig. In the comparative example, the film thickness of the mixed layer becomes larger as the film thickness of the insulating film becomes thinner, and the possibility of short-circuiting becomes higher at the film thickness of the insulating film of 25 m or less. As a result of the die coating method of the present embodiment, even if the insulating layer has a smaller thickness, the film thickness of the mixed layer is 5 m or less, and the possibility of occurrence of short circuit is low.

In Examples 1 and 2 described above, examples in which a positive electrode material (PAS) and an insulating material (IF) were applied to one surface of a positive electrode plate (PEP) to manufacture a positive electrode sheet were described. When applying the positive electrode material (PAS) and the insulating material (IF) to both surfaces of the positive electrode plate (PEP), the positive electrode sheet wound around the winding roll 5 (RL5) is reversed, It is thought to construct.

In Examples 1 and 2, an example of a process for producing a positive electrode sheet was shown. Using the same die coating method, the negative electrode sheet manufacturing process can also be realized. In this case, the negative electrode material (NAS) is obtained by kneading a negative electrode active material containing a carbon material (carbon material) and a binder (binder) containing polyvinylidene fluoride dissolved in N methyl pyrrolidone (NMP) Use one slurry.

The insulating material IF is a slurry obtained by kneading a powder of silica (SiO ₂ ) into a solution in which a binder (polyvinylidene fluoride-containing binder) is dissolved in N-methylpyrrolidone (NMP).

In the negative electrode sheet production process, negative electrode sheets (NAS) and insulating material (IF) are overlaid on the negative electrode plate (NEP) and negative electrode sheet (NAS) Both of which are considered.

In addition, the present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail in order to facilitate a better understanding of the present invention, and the present invention is not limited thereto. It is also possible to replace some of the configurations of some embodiments with those of other embodiments, and it is also possible to add configurations of other embodiments to the configurations of some embodiments. In addition, it is possible to add, delete, or substitute another configuration for a part of the configuration of each embodiment.

In the first and second embodiments, the technical idea of the present invention has been described by taking a lithium ion secondary battery as an example. However, the technical idea of the present invention is not limited to a lithium ion secondary battery, (For example, a battery or a capacitor) having a separator for electrically separating the positive electrode and the negative electrode from each other.

RL1: Positive electrode plate discharge roll
RL2: Roller 2
RL3: Roller 3
RL4: Roller 4
RL5: Coiling Roll
RL6: Roller 6
PEP: positive plate
DC1: Slit die coater 1
DC2: Slit die coater 2
PAS: positive active material
CC1: Curtain Coater
IF: Insulation material
DRY: Drying furnace
SEL: insulation layer
EL: electrode layer
EP: Electrode plate
MIX: Mixed layer
71: slit die coater detaching member
72: Curtain Coater Detaching Member
73: Manifold
74: slit
75: electrode material reservoir (bead)
76: Manifold
77: slit
78: The downstream side lip portion of the crotch member 71
79: downstream meniscus
80: Curtain film of insulating material
81: Carrier material (positive electrode sheet material)
h1: interval between slit die coater claw member and carrier material
h2: interval between the curtain coater caged member and the carrier material

Claims (8)

A method of manufacturing a lithium ion secondary battery having a positive electrode, a negative electrode, and a separator for electrically separating the positive electrode and the negative electrode,
An electrode material is applied by a slit die coater to an electrode substrate supplied at a predetermined speed and an insulating material is coated and formed on the electrode material layer on the electrode substrate on the downstream side by a curtain coater, Is dried and fixed to produce an electrode sheet. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
The positive electrode material (PAS) is obtained by mixing an active material containing lithium cobalt oxide and carbon as a conductive auxiliary agent, mixing a binder (polyvinylidene fluoride-containing binder) with N-methylpyrrolidone (NMP) The slurry obtained in the step
The negative electrode material (NAS) is prepared by using a slurry obtained by kneading a negative electrode active material containing a carbon material (carbon material) in a solution obtained by dissolving a binder (binder) containing polyvinylidene fluoride in N methyl pyrrolidone (NMP) ≪ / RTI > wherein the lithium ion secondary battery is a lithium ion secondary battery. The method according to claim 1,
Characterized in that the insulating material is a slurry obtained by kneading a powder of silica (SiO ₂ ) into a solution in which a binder (binder) containing polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) A method of manufacturing a secondary battery. The method according to claim 1,
An insulating material is coated on a layer of the electrode material on the electrode substrate supplied at a predetermined speed with a curtain coater and then the coating film height is adjusted by a knife coater and charged into a drying furnace A method of manufacturing a secondary battery. An electrode substrate feed roll for feeding the electrode substrate at a predetermined speed,
First, second and third rollers for feeding the electrode substrate at a predetermined speed,
A slit die coater for applying an electrode material to the electrode substrate from a position opposing the first roller,
A curtain coater downstream of the slit die coater for applying an insulation material onto a layer of electrode material on the electrode substrate from a position opposing the second roller;
A drying furnace for drying and fixing the electrode material and the layer of the insulating material applied on the electrode substrate on the downstream side of the curtain coater,
And a winding roll for winding the electrode substrate on which the electrode material and the insulating material are fixed. 6. The method of claim 5,
Further comprising a knife coater downstream of the curtain coater and upstream of the drying furnace to adjust a coating film height on the electrode substrate. 6. The method of claim 5,
The positive electrode material (PAS) of the electrode material is prepared by mixing an active material containing lithium cobalt oxide and carbon as a conductive auxiliary agent so that a binder containing polyvinylidene fluoride (binder) is dissolved in N-methylpyrrolidone The slurry obtained in the step
The negative electrode material (NAS) is prepared by using a slurry obtained by kneading a negative electrode active material containing a carbon material (carbon material) in a solution obtained by dissolving a binder (binder) containing polyvinylidene fluoride in N methyl pyrrolidone (NMP) Wherein the lithium ion secondary battery is a lithium ion secondary battery. 6. The method of claim 5,
Characterized in that the insulating material is a slurry obtained by kneading a powder of silica (SiO ₂ ) into a solution in which a binder (binder) containing polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) A device for manufacturing a secondary battery.

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