JP2000012003A - Lithium ion secondary battery production equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lithium ion secondary battery production equipment, capable of preventing mixing of metal impurities into a raw material. SOLUTION: A crusher 100 has a crushing chamber 104, a hammer 112, a guide ring 114, and a classifying separator 116. The hammer 112 rotates at a high speed within the crushing chamber 104 to crush a raw material 118. The guide ring 114 sends the crushed raw material to the classifying separator 116 by the flow of dry air. The classifying separator 116 selects the specified particles or lower from the particles of the crushed raw material sent with the guide ring 114 and allows only the selected particles to pass through. The surface of the hammer 112, the surface of the guide ring 114, the surface of the classifying separator, and an inner wall surface 104A of the crushing chamber 104, which comes in contact with the raw material 118, are coated with a non-metallic material such as ceramic or Teflon (registered trademark) as shown by hatched sections.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a facility for manufacturing a lithium ion secondary battery.

[0002]

2. Description of the Related Art Conventionally, lead batteries, nickel cadmium batteries, and the like have been used as secondary batteries, but these batteries have overcome the problems of increasing energy density and reducing weight. Absent. Therefore, in recent years, non-aqueous lithium ion secondary batteries with high energy density have been put to practical use. This lithium ion secondary battery is
It is a storage battery composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. Lithium-ion secondary batteries have the following characteristics: when charged, lithium ions in the positive electrode are occluded in the negative electrode via the electrolytic solution, and lithium ions in the negative electrode are occluded in the positive electrode via the electrolytic solution. It utilizes a chemical reversible reaction.

However, if metal impurities are mixed in the positive electrode of a lithium ion secondary battery, the battery characteristics, particularly the battery characteristics against overcharging, are adversely affected. Measures are taken to prevent metal impurities from being mixed into the raw material from the part in contact with the raw material (positive electrode active material) constituting the electrode or from the part facing the raw material. For example, a stainless steel material or a super hard material having excellent wear resistance is used for a portion in contact with the raw material, and a stainless steel or chrome plating having excellent corrosion resistance is applied to a portion facing the raw material.

[0004]

However, in a pulverizing apparatus for pulverizing a raw material, it is inevitable that metal impurities are mixed in the raw material due to abrasion of a part in contact with the raw material. In addition, in a drying device that forms an electrode by drying an electrode mixture paint (made by kneading raw materials and a solvent) applied to a metal foil current collector, the heat generated during drying and the electrode mixture paint are included. It is inevitable that the inside of the drying device is corroded by the substance of the solvent and metal impurities are mixed into the electrode mixture paint of the electrode. Such metal impurities are more likely to be generated as the pulverizing device or the drying device is operated, that is, as the productivity is increased, which is a factor of reducing the productivity. Therefore, an object of the present invention is to provide a lithium-ion secondary battery manufacturing facility for manufacturing a lithium-ion secondary battery from raw materials, by preventing metal impurities from being mixed into the raw materials, thereby providing a high-quality lithium-ion secondary battery. An object of the present invention is to provide a lithium-ion secondary battery manufacturing facility that can be manufactured and that can improve productivity.

[0005]

In order to achieve the above object, the present invention relates to a lithium ion secondary battery manufacturing facility for manufacturing a lithium ion secondary battery from raw materials, in a part where the raw materials come into contact or a part facing the raw materials. Is characterized by being provided with a coating made of a nonmetallic material.

[0006] In the present invention, since the portion that comes into contact with the raw material or the portion that faces the raw material is coated with a nonmetallic material, the metal impurity generated from the portion that comes into contact with the raw material or the portion that faces the raw material is provided. Is prevented from being mixed into the raw material.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a pulverizing apparatus showing an embodiment of a lithium ion secondary battery manufacturing facility of the present invention,
FIG. 2 is a schematic view of an apparatus used in a step of applying and drying an electrode mixture paint on a metal foil, which is a part of an electrode manufacturing process of a lithium ion secondary battery, FIG. 3 is a schematic view of a drying apparatus, and FIG. FIG. 1 is an explanatory view showing a main part of a drying apparatus showing an embodiment of a facility for manufacturing a lithium ion secondary battery of the present invention, and FIG. 5 is an exploded view showing a structure of the lithium ion secondary battery.

First, the structure of a lithium ion secondary battery will be described with reference to FIG. The lithium ion secondary battery 10 includes a positive electrode cover 10A, a safety valve 10B, a positive electrode lead 10
C, gasket 10D, insulating plate 10E, positive electrode 10F, separator 10G, negative electrode 10H, insulating plate 10I, negative electrode can 1
0J, a negative electrode lead 10K, a case 10L, and the like. The positive electrode 10F is formed by applying a positive electrode active material to a sheet-shaped metal foil current collector and drying it. The negative electrode 10H is formed by applying a negative electrode active material to a sheet-shaped metal foil current collector. Is applied and dried. The positive electrode 10F and the negative electrode 10H are separated from each other by a separator 10G.
Is wound spirally around the central axis of the cylindrical case 10L with the
0L. Since the adverse effect on the characteristics of the battery is caused only when the metal impurities are mixed in the raw material of the positive electrode, the following description will be made on the positive electrode.

Next, referring to FIG. 1, a description will be given of a pulverizing apparatus constituting the lithium ion secondary battery manufacturing equipment according to the present embodiment. The crushing apparatus 100 includes a main body 102, a crushing chamber 104, a raw material inlet 106, a dry air inlet 1
08, transport port 110, hammer 112, guide ring 1
14, a classification separator 116 and the like.

A crushing chamber 104 is provided inside the main body 102, and a raw material introduction port 106 for introducing a raw material 118 so as to communicate with the crushing chamber 104, and a dry air introduction for introducing dry air. A port 108 and a transfer port 110 for discharging the pulverized raw material together with the dry air are provided. A raw material introduction path 122 for transferring a raw material supplied from a raw material supply unit (not shown) communicates with the raw material introduction port 106, and a raw material 118 is transferred into the grinding chamber 104 in the raw material introduction path 122. Transfer means 120 is provided.

A flow path 124 is formed below the pulverizing chamber 104 and communicates with the dry air inlet 108 to guide dry air supplied from a dry air supply source (not shown) to the dry air inlet 108. . The dry air supplied to the dry air inlet 108 passes through the classifier 116 between the guide ring 114 and the inner wall surface of the crushing chamber 104 in the crushing chamber 104 and passes through the outlet 110.
And the discharge path 12 communicating with the discharge port 110
It flows along 6.

The crushing chamber 104 has a substantially cylindrical space when viewed from above, and includes a hammer 112, a guide ring 114,
The classification separator 116 is housed. Hammer 112
Is configured to rotate at a high speed around a shaft 122 in the crushing chamber 104 and crush the raw material by colliding with the raw material 118 introduced into the crushing chamber 104 from the raw material inlet 106.

The guide ring 114 separates the raw material pulverized by the hammer 112 from the classification separator 1 by the flow of dry air introduced from the dry air inlet 108.
16. Classification separator 11
Numeral 6 is configured to allow the pulverized raw material guided by the guide ring 114 to pass through a material having a particle size equal to or smaller than a predetermined particle size. Classification separator 11
The pulverized raw material passing through 6 is transferred from the outlet 110 to the discharge path 126 by the flow of dry air. Further, this classification separator 116 is a shaft 1
It rotates around 22.

Then, a portion that comes into contact with the raw material 118, that is, the surface of the hammer 112 and the guide ring 114
, The surface of the classification separator 116, and the crushing chamber 10
4 is coated with a nonmetallic material, for example, ceramic or Teflon.
In the figure, a portion indicated by reference numeral C (hatched portion) is a surface coated with a nonmetallic material.

Therefore, according to the above-described configuration, since the portion in contact with the raw material 118 is coated with the non-metallic material, even if the pulverizing apparatus 100 is operated to pulverize the raw material 118, the raw material 118 is not contacted. The metal material in the portion to be removed is less likely to be worn, and the metal impurities are prevented from being mixed into the raw material. As a result, a high-quality lithium ion secondary battery can be manufactured, and productivity can be improved.

Next, the steps of applying and drying the electrode mixture paint on the metal foil current collector, which is a part of the electrode manufacturing step of the lithium ion secondary battery, will be described with reference to FIG. The metal foil (metal foil current collector) 202 unwound from the unwinding roll 200 travels on a transport path, and an electrode mixture paint 205 is applied by a coater head 204. The electrode mixture paint is made by kneading the raw material and the solvent pulverized by the pulverizer 100 with a kneader. Next, the electrode mixture paint applied to the metal foil 202 is applied to a drying device 2 described later.
06 and dried. Then, the metal foil 202 on which the electrode mixture paint has been dried is pressed by a press 208, and then cut into predetermined dimensions by a cutting cutter 210, thereby completing the electrode. The completed electrode is taken up by a take-up roll 212.

Next, the configuration of the drying apparatus will be described with reference to FIG. The drying device 206 includes a blower 2061, a heat source 2062, a filter unit 2063, a dryer 2064, and a chamber 2065. Blower 2
061 is heated by passing through the heat source 2062 to become hot air,
, And passes through the filter unit 2063 to become clean air, which is adjusted to an appropriate air volume by the chamber 2065. The dryer 2064 is provided in the chamber 2065, and includes a transport path on which the metal foil coated with the electrode mixture paint travels, and a hot air nozzle 2064A for blowing the clean air adjusted in the chamber 2065 onto the metal foil. Have.

Next, the dryer 2064 of the drying device 206 will be described with reference to FIG. Dryer 206
4 is a hot air nozzle 2064A, a transport path 2064B in which the metal foil coated with the electrode mixture paint travels,
64C. The metal foil 202 to which the electrode mixture paint 205 has been applied is adapted to travel on a transport path 2064B. Then, hot air is blown from the hot air nozzle 2064A to the surface of the metal foil 202 on which the electrode mixture paint 205 is applied, whereby the electrode mixture paint 2 is sprayed.
05 is to be dried. Hot air nozzle 2064
A and the transport path 2064B are accommodated in a drying chamber 2064C.

The electrode mixture paint 205 as a raw material
, That is, the inner wall surface of the drying chamber 2064C,
The wall surface through which the hot air passes inside the hot air nozzle 2064A is coated with a nonmetallic material, for example, ceramic or Teflon. In the figure, a portion indicated by reference numeral C (hatched portion) is a surface coated with a nonmetallic material.

Therefore, according to the above-described configuration, since the portion facing the electrode mixture paint 205 as a raw material is coated with a non-metallic material, the drying device 206 can dry the electrode mixture paint 205 when drying. The metal material in the portion of the drying device 206 facing the electrode mixture paint 205 is less likely to be corroded by heat generated during drying or a solvent substance contained in the electrode mixture paint, and metal impurities generated by the corrosion adhere to the electrodes. Is prevented. As a result, a high-quality lithium ion secondary battery can be manufactured, and productivity can be improved.

Next, the evaluation results of the lithium ion secondary battery manufactured by the lithium ion secondary battery manufacturing equipment of the present invention will be described. FIG. 6 shows the measurement results of the amount of the magnetic metal component after one month and six months when the positive electrode active material was pulverized for six consecutive months under the following three conditions for the pulverizer. Condition 1a: The classification separator and the guide ring were coated with ceramic. Condition 1b: A superhard material having excellent wear resistance was sprayed on the classification separator and the guide ring. Condition 1c: The classification separator and the guide ring are made of stainless steel, and no surface treatment is performed. As shown in FIG. 6, when the ceramic is coated, Fe (iron) which is a magnetic metal component even after 6 months has passed.
Has not increased. On the other hand, in the case of the cemented carbide material, the value is the same as that obtained when the ceramic is coated after one month, but the magnetic metal component increases after 6 months.

FIG. 7 shows a case where a lithium ion secondary battery incorporating a positive electrode using the positive electrode active material manufactured under the above-described conditions 1a to 1c was prepared, and charging and discharging were repeatedly performed with this lithium ion secondary battery. Fig. 9 shows the result of observing the ratio of short-circuiting inside the battery. Note that the internal short-circuit failure rate is calculated based on the percentage of batteries in which internal short-circuit has occurred among 100 batteries. As shown in FIG. 7, when the ceramic is coated, the internal short-circuit failure rate hardly changes over time, whereas when the super hard material is thermally sprayed and when the surface treatment is not performed. As the time elapses, the internal short-circuit failure rate increases. That is, the result corresponds to the transition of the magnetic metal component mixed in the positive electrode active material shown in FIG.

FIG. 8 shows the drying apparatus under the following three conditions.
1 when the positive electrode is formed by drying for 6 consecutive months
It is a measurement result of the amount of magnetic metal components contained in the positive electrode after 6 months and 6 months. Condition 2a: The inner wall surface of the drying chamber and the wall surface through which warm air passes inside the warm air nozzle were coated with ceramic. Condition 2b: The inner wall surface of the drying chamber and the wall surface through which warm air passes inside the warm air nozzle were coated with chrome plating having excellent corrosion resistance. Condition 2c: The drying chamber and the hot air nozzle are made of stainless steel, and no surface treatment is performed on the inner wall surface of the drying chamber and the wall surface through which the hot air passes inside the hot air nozzle. As shown in FIG. 8, when the ceramic is coated, Fe (iron) which is a magnetic metal component even after 6 months has passed.
Has not increased. On the other hand, when the chromium plating is performed, the value is the same as that when the ceramic is coated after one month, but the magnetic metal component increases after 6 months. In the case of chromium plating, it is considered that the chromium plating is corroded by the solvent contained in the electrode mixture paint, for example, oxalic acid, and the metal component of the base is mixed into the positive electrode.

FIG. 9 shows a lithium ion secondary battery incorporating the positive electrode manufactured under the above conditions 2a to 2c.
The result of observing the ratio of short-circuiting inside the battery when charging and discharging are repeatedly performed in the lithium ion secondary battery is shown. In addition, the internal short-circuit defect rate is as follows:
It is calculated based on the percentage of batteries in which an internal short circuit has occurred.
As shown in FIG. 9, when the ceramic was coated, the internal short-circuit failure rate hardly changed with the elapse of time, whereas when the chrome plating was performed and when the surface treatment was not performed, The internal short-circuit defect rate increases with time. That is, the result corresponds to the transition of the magnetic metal component mixed in the positive electrode active material shown in FIG.

The lithium ion secondary battery manufacturing equipment of the present invention is not limited to a pulverizing device and a drying device, but a kneading device for kneading a raw material (a positive electrode active material) and a solvent to produce an electrode mixture paint. It can also be applied to That is,
The inner wall surface of the chamber of the kneading device is a portion that comes into contact with the raw materials. Therefore, by coating the inner wall surface of the chamber, the mixing of the magnetic metal component can be prevented as in the case of the above-described pulverizing device and drying device.

[0026]

As is clear from the above description, the present invention
In a lithium ion secondary battery manufacturing facility for manufacturing a lithium ion secondary battery from raw materials, a portion made of a non-metallic material is applied to a portion where the raw materials come into contact or a portion facing the raw materials. Therefore, since the portion where the raw material contacts or the portion facing the raw material is coated with a non-metallic material, metal impurities generated from the portion where the raw material contacts or the portion facing the raw material are mixed into the raw material. Is prevented. As a result, a high-quality lithium ion secondary battery can be manufactured, and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a pulverizing apparatus showing an embodiment of a facility for manufacturing a lithium ion secondary battery of the present invention.

FIG. 2 is a schematic view of an apparatus used in a process of applying and drying an electrode mixture paint on a metal foil, which is a part of a process for manufacturing an electrode of a lithium ion secondary battery.

FIG. 3 is a schematic view of a drying device.

FIG. 4 is an explanatory view showing a main part of a drying apparatus showing an embodiment of the facility for manufacturing a lithium ion secondary battery of the present invention.

FIG. 5 is an exploded view showing a structure of a lithium ion secondary battery.

FIG. 6 is a diagram showing, in a table format, measurement results of a temporal change in the amount of a magnetic metal component contained in a positive electrode active material when the present invention is applied to a pulverizer.

FIG. 7 is an explanatory diagram showing a temporal transition of a battery internal short-circuit failure rate when the present invention is applied to a pulverizer.

FIG. 8 is a diagram showing, in a table format, measurement results of a temporal change in the amount of a magnetic metal component contained in a positive electrode active material when the present invention is applied to a drying device.

FIG. 9 is an explanatory diagram showing a temporal transition of a battery internal short-circuit failure rate when the present invention is applied to a drying device.

[Explanation of symbols]

100 crushing apparatus 104 crushing chamber 112 hammer 114 guide ring 116 classification separator 118 raw material 202 metal foil (metal foil current collector) 205 205 Electrode mixture paint, 206 drying device, 2064 dryer, 2064A hot air nozzle, 2046B transport path, 2064C drying room, C
...... Coating surface.

Claims (6)

[Claims] 1. In a lithium ion secondary battery manufacturing facility for manufacturing a lithium ion secondary battery from raw materials, a portion made of a non-metallic material is applied to a portion contacting the raw material or a portion facing the raw material. A lithium-ion secondary battery manufacturing facility characterized by the following. 2. The lithium ion secondary battery manufacturing equipment according to claim 1, wherein the raw material is a positive electrode active material constituting a positive electrode of the lithium ion secondary battery. 3. The part where the raw material comes into contact is a hammer, a guide ring, a classification separator, and a pulverizing chamber provided in a pulverizing device for pulverizing the raw material, and the hammer collides with the raw material to reduce the raw material. Configured to pulverize, the guide ring is configured to guide the pulverized raw material to the classification separator, the classification separator is configured to select and pass a raw material having a predetermined particle size or less, the pulverization chamber Is configured to receive the hammer, the guide ring, and the classification separator, and the coating includes at least one of a hammer surface, a guide ring surface, a classification separator surface, and an inner wall surface of a grinding chamber. The lithium-ion secondary battery manufacturing facility according to claim 2, wherein 4. A part where the raw material faces is a drying chamber of a drying device for drying an electrode mixture paint in which the raw material and a solvent are kneaded applied to a metal foil current collector; A hot-air nozzle for spraying the electrode mixture paint applied to the body, wherein the drying chamber is configured to accommodate a transport path along which the metal foil current collector travels and the hot-air nozzle; Is disposed so as to blow hot air onto the surface of the metal foil current collector traveling on the transport path, on which the electrode mixture paint is applied, and the coating is formed on an inner wall surface of the drying chamber and the hot air. 3. The lithium ion secondary battery manufacturing facility according to claim 2, wherein the facility is provided on at least one of a wall surface through which warm air passes inside the nozzle. 5. A part of the kneading device in which the raw material comes into contact with the raw material and a solvent for kneading the solvent to form an electrode mixture paint, wherein the coating is applied to an inner wall surface of the chamber. 3. The facility for manufacturing a lithium ion secondary battery according to claim 2, wherein: 6. The facility according to claim 1, wherein the non-metallic material is ceramic or Teflon.