JP7069666B2 - Method for manufacturing lithium nickel composite oxide and method for manufacturing non-aqueous electrolyte secondary battery - Google Patents

Description

The present invention relates to a method for producing a lithium nickel composite oxide and a method for producing a non-aqueous electrolyte secondary battery.

In recent years, with the spread of portable electronic devices such as mobile phones and notebook personal computers, the development of a compact and lightweight lithium-ion secondary battery having a high energy density is strongly desired. In addition, the development of high-power secondary batteries suitable for environment-friendly automobile applications such as hybrid automobiles and electric automobiles is also strongly desired.

As a secondary battery satisfying such a demand, there is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The non-aqueous electrolyte secondary battery is composed of a negative electrode, a positive electrode, a non-aqueous electrolyte, and the like, and a material capable of desorbing and inserting lithium is used as an active material for the negative electrode and the positive electrode.

Currently, research and development are being actively carried out on non-aqueous electrolyte secondary batteries. Among them, non-aqueous electrolyte secondary batteries using layered or spinel-type lithium nickel composite oxide as the positive electrode active material are available. Since a high voltage of 4V class can be obtained, it is being put into practical use as a battery having a high energy density.

Lithium-nickel composite oxides that have been proposed as positive electrode active materials so far include lithium-cobalt composite oxide (LiCoO ₂ ), which is relatively easy to synthesize, and lithium-nickel composite oxide using nickel, which is cheaper than cobalt. (LiNiO ₂ ), Lithium-nickel-cobalt-manganese composite oxide with excellent safety using cheaper manganese (for example, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), spinel-based lithium-manganese composite oxide (LiMn ₂ O ₄ ) and the like can be mentioned.

Among these, lithium-nickel composite oxide is attracting attention as having a high capacity and high output and satisfying the characteristics required for future environment-friendly automobiles, and its demand is rapidly expanding.

Furthermore, environmentally friendly automobiles are required to be reduced in price as the demand increases. Therefore, there is an increasing demand for cost reduction of lithium ion secondary batteries, which is one of the high cost factors of environment-friendly automobiles, and the cost of positive electrode active materials, which is one of the positive electrode materials of lithium secondary batteries, is also reduced. It has been demanded.

The lithium nickel composite oxide can be obtained by mixing a compound containing nickel and a compound containing lithium to prepare a lithium mixture (raw material mixture), and then firing the lithium mixture. Firing of the lithium mixture is carried out, for example, at a temperature of about 650 ° C. or higher and 950 ° C. or lower for 8 hours or longer. During this firing step, the lithium-containing compound reacts (sinters) with the nickel-containing compound (precursor) to obtain a lithium-nickel composite oxide having high crystallinity.

When the lithium nickel composite oxide is industrially produced, generally, the powder of the lithium mixture is put in a container such as a bowl and fired in a horizontal firing furnace such as a roller herskilln or a pusher furnace. To. However, when powder is put in a container and fired, heat conduction is poor and the replaceability between the generated gas and the reaction gas is also poor. Therefore, it takes a long time to produce a lithium nickel composite oxide having high crystallinity. It takes time to raise the temperature and react, and the total firing time including these becomes very long.

Several proposals have been made so far to solve such problems. For example, Patent Document 1 describes that in a step of filling a firing container with a mixture (powder) obtained by mixing a nickel composite compound and a compound containing lithium and firing the mixture, oxygen is sufficiently diffused in the mixture. The minimum holding time and the range of oxygen concentration to be held in a specific temperature range with respect to the filling amount of the mixture (thickness when the mixture is placed in the firing container) are specified, and the mixture is fired as efficiently as possible. The method is shown.

Also disclosed are some methods of granulating a lithium mixture to obtain granulated products or molding to obtain a molded product and then firing to obtain a lithium nickel composite oxide. For example, Patent Document 2 describes a product obtained by granulating the raw material mixture when at least a nickel salt and a lithium salt are mixed in a predetermined amount to form a raw material mixture, and the raw material mixture is fired to synthesize LiNiO ₂ . It is described that the granules are held at a temperature of 700 ° C. to 1000 ° C. for 2 to 15 hours and fired in an oxidizing atmosphere to obtain a LiNiO ₂ -based layered composite oxide. According to Patent Document 2, a compound having a desired crystal structure can be produced with high productivity, including a work surface, by the above production method.

On the other hand, as a firing furnace for firing powder, a vertical furnace (vertical furnace) may be used. In a vertical furnace, powder can be fired continuously, and consumables such as a rutsubo or saggar for storing powder are not required, so the cost related to consumables such as rutsubo or saggar can be reduced, and the cost of consumables such as rutsubo or saggar can be reduced. There is an advantage that the transfer mechanism becomes unnecessary, the structure of the firing furnace is simplified, and the equipment cost is reduced (see, for example, Patent Document 3).

Further, for example, Patent Document 4 describes a powder firing method using a vertical firing furnace for powder firing, in which a molded body obtained by press-molding or pressure-absorbing powder is used as a material to be fired and is laminated in the furnace. It is described that the molded body is fired while intermittently descending and moving from the upper inlet to the lower outlet of the vertical firing furnace.

Japanese Unexamined Patent Publication No. 2011-146309 Japanese Unexamined Patent Publication No. 11-135123 Japanese Unexamined Patent Publication No. 2016-052646 Japanese Unexamined Patent Publication No. 2010-121856

However, in the production method described in Patent Document 1, if the filling amount of the mixed powder is increased in order to increase the productivity, the temperature rise time of the mixed powder is extended, and the replacement of the generated gas and the reaction gas is deteriorated. May become longer and productivity may be impaired. Further, in the examples of Patent Document 2, the firing condition is set to 800 ° C. for 10 hours or more, and the production method described in Patent Document 2 may take a long time to produce the lithium nickel composite oxide. Further improvement in productivity is required.

Further, when firing by the production methods of Patent Documents 1 and 2, a method of putting the raw material powder in a crucible or a sack and firing is widely used. There is a problem that the crucible or saggar deteriorates and is damaged by repeated use. Due to this problem, there is a limitation in reducing the production cost of the positive electrode active material.

As described above, when the vertical furnace is used, since the crucible or the sack is not used, the problem of the increase in the manufacturing cost due to the breakage of the crucible or the saggar can be solved. However, when the lithium-nickel composite oxide is produced by firing the powder of the lithium mixture using a vertical furnace as described in Patent Document 3, the powder of the compound containing nickel and lithium are calcined during firing. There is a problem that separation occurs due to the difference in specific gravity of the contained compound from the powder, and the reaction (sintering) between the nickel-containing compound and the lithium-containing compound becomes insufficient. Further, there is a problem that the compound containing lithium dissolves during firing and is sintered in the furnace, causing clogging in the furnace.

Further, Patent Document 4 describes a manufacturing method in which a powder (molded body) obtained by press-molding an object to be fired is fired in a vertical furnace. However, in Patent Document 4, a conical pot-shaped molded body having a maximum diameter slightly smaller than the inner diameter of the core tube is fired by intermittently moving downward in the core tube (inside the furnace) one by one. Although it has the advantage of uniformly transferring heat compared to filling the furnace with powder and firing it, the efficiency of supplying the reaction gas to the inside of the molded body and desorbing the gas generated by the reaction from the molded body is efficient. There is a limit to shortening the residence time in the furnace, and there is a problem in productivity.

In view of the above problems, the present invention can improve the productivity by shortening the firing time of the lithium mixture, and reduce the manufacturing cost without using consumables such as a rutsubo or a bowl. A method for producing an oxide is provided. Further, the present invention provides a method for producing a non-aqueous electrolyte secondary battery, which can further improve productivity and reduce costs by using the lithium nickel composite oxide obtained by the production method.

According to the first aspect of the present invention, a method for producing a lithium nickel composite oxide by calcining a nickel-containing compound and a lithium-containing compound, wherein the nickel-containing compound and the lithium-containing compound are produced. A plurality of molded bodies obtained by molding a mixture containing the powder of and are continuously or intermittently supplied from the upper part of the vertical furnace into the furnace, and the molded bodies are formed in the vertical furnace. It comprises firing and discharging a plurality of fired molded bodies from the lower part of the vertical furnace to the outside continuously or intermittently, and the molded body is formed between any two points on the outer shape. Provided is a method for producing a lithium nickel composite oxide having a maximum distance of 5 mm or more and a density of a molded product of 1.5 g / cm ³ or more and 2.5 g / cm ³ or less .

In addition, firing the molded body means that during the firing process, the molded body that has been fired is discharged from the lower part of the vertical furnace, and the molded body before firing is supplied from the upper part of the vertical furnace into the furnace. This may include firing while moving the molded product from above to below. Further, it may be provided that the molded product discharged to the outside from the lower part in the vertical furnace is crushed to obtain a powder of a lithium nickel composite oxide. Further, the molded body was supplied into the vertical furnace from the molded body supply device arranged above the vertical furnace, and the fired molded body was arranged below the vertical furnace from the inside of the vertical furnace. It may be provided that it is discharged to a molded body discharging device. In addition, the vertical furnace is equipped with a heating zone for heating and firing the molded body in the furnace, and the reaction gas is supplied from below the heating zone to bring it into contact with the molded body in the vertical furnace and above the heating zone. It may be provided to exhaust from. Further, the vertical furnace may be provided with a cooling zone for cooling the molded product below the heating zone, and the reaction gas may be supplied from below the cooling zone to cool the calcined molded product. ..

Further, according to the aspect of the present invention, a method for producing a lithium nickel composite oxide by firing a nickel-containing compound and a lithium-containing compound, wherein the nickel-containing compound and the lithium-containing compound are used. A plurality of molded bodies obtained by molding a mixture containing the powder of the above are continuously or intermittently supplied from the upper part of the vertical furnace into the furnace, and the molded bodies are fired in the vertical furnace. And the firing of multiple fired moldings from the bottom of the vertical furnace to the outside, either continuously or intermittently, with ceramics before feeding the moldings into the vertical furnace. The balls are supplied into the vertical furnace and heated until the inside of the vertical furnace reaches the firing temperature, and after the inside of the vertical furnace reaches the firing temperature, the ceramic balls are sent from the bottom of the vertical furnace to the furnace. A method for producing a lithium nickel composite oxide is provided, which comprises supplying a plurality of molded bodies from the upper part of a vertical furnace into the furnace while discharging them to the outside. In addition, the ceramic balls discharged to the outside of the vertical furnace and the molded body are collected together, and the collected collected material is shaken to crush the molded body and to screen the crushed molded body. Then, it may be provided to separate from the ceramic ball and collect it. Further, the lithium nickel composite oxide may be used as the positive electrode active material of the non-aqueous electrolyte secondary battery.

According to the second aspect of the present invention, a positive electrode is obtained by using the lithium nickel composite oxide produced by the above-mentioned production method as a positive electrode active material, and the above-mentioned positive electrode, negative electrode, and non-aqueous electrolyte are used. Provided is a method for manufacturing a non-aqueous electrolyte secondary battery, comprising obtaining a non-aqueous electrolyte secondary battery.

According to the method for producing a lithium-nickel composite oxide of the present invention, the firing time can be shortened, and thus the productivity can be improved. Further, according to the above-mentioned manufacturing method, since consumables such as a crucible or a sack are not used, the manufacturing cost can be reduced. Further, according to the method for producing a non-aqueous electrolyte secondary battery of the present invention, the productivity can be further improved and the production cost can be reduced by using the lithium nickel composite oxide obtained by the above production method. can.

FIG. 1 is a flowchart showing an example of a method for producing a lithium nickel composite oxide according to the first embodiment. FIG. 2 is a schematic view showing an example of a manufacturing apparatus used in the method for manufacturing a lithium nickel composite oxide according to the first embodiment. FIG. 3 is a schematic diagram showing an example of a method for producing a lithium nickel composite oxide according to the second embodiment. FIG. 4 is a schematic explanatory view of the coin-type secondary battery used in the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, in the drawings, in order to make each configuration easy to understand, a part is emphasized or a part is simplified, and the actual structure, shape, scale, etc. may be different. Further, in each of the following figures, the directions in the figure will be described using the XYZ coordinate system. In this XYZ coordinate system, the vertical direction is the Z direction, and the horizontal direction is the X direction and the Y direction. Further, in each of the X direction, the Y direction, and the Z direction, the side at the tip of the arrow is referred to as a + side (eg, + X side), and the opposite side is referred to as a − side (eg, −X side).

[First Embodiment]
1. 1. Method for Producing Lithium-Nickel Composite Oxide In the method for producing a lithium-nickel composite oxide according to the first embodiment (hereinafter, also referred to as “manufacturing method”), a compound containing nickel and a compound containing lithium are fired to form lithium. This is a method for producing a nickel composite oxide. The production method according to the present embodiment can produce a lithium nickel composite oxide with high productivity and low cost. Further, by using the production method of the present embodiment, a lithium nickel composite oxide that can be suitably used as a positive electrode active material for a non-aqueous electrolyte secondary battery is produced on an industrial scale in a large amount and at low cost. be able to.

FIG. 1 is a flowchart showing an example of the manufacturing method of the present embodiment. FIG. 2 is a diagram showing an example of a manufacturing apparatus used in the manufacturing method of the present embodiment. Hereinafter, the manufacturing method of the present embodiment will be described with reference to FIGS. 1 and 2 as appropriate.

In the production method according to the present embodiment, as shown in FIG. 1, a plurality of molded bodies obtained by molding a mixture (lithium mixture) containing a powder of a compound containing nickel and a compound containing lithium are vertically formed. Continuously or intermittently supplying from the upper part of the mold furnace to the inside of the furnace (step S10), firing the molded product in the vertical furnace (step S20), and firing a plurality of fired moldings. The body is continuously or intermittently discharged from the lower part of the vertical furnace to the outside (step S30).

In the production method of the present embodiment, by using the molded product of the lithium mixture in step S10, separation of the powder of the compound containing nickel and the powder of the compound containing lithium occurs due to the difference in specific gravity in the firing by the vertical furnace. The lithium mixture can be reacted uniformly without this, and the firing time can be shortened.

Further, in step S10, a plurality of molded bodies are continuously or intermittently supplied from the upper part of the vertical furnace to form a gap between the supplied molded bodies, and the vertical furnace is formed through the gap. Since the reaction gas and heat supplied from the above, the generated gas generated from the molded body, etc. can flow, the lithium mixture can be reacted more uniformly, and the sintering reaction can be promoted to shorten the firing time. Become.

Hereinafter, the manufacturing method of the present embodiment will be further described. First, the molded body and the manufacturing apparatus used in the manufacturing method of the present embodiment will be described, and then each step in the manufacturing method will be described.

(1) Molded body The molded body used in the present embodiment is obtained by molding a mixture (lithium mixture) obtained by mixing a powder of a compound containing nickel and a compound containing lithium (FIG. 1). See steps S1 and S2). Hereinafter, each raw material constituting the molded body and a method for manufacturing the molded body will be described.

(Compound containing nickel)
The nickel-containing compound used in the present embodiment is not particularly limited, and known compounds can be used. As the compound containing nickel, for example, at least one of a hydroxide containing nickel and an oxide containing nickel can be used.

(Hydroxides containing nickel)
The hydroxide containing nickel includes a nickel hydroxide and a hydroxide containing nickel and a metal other than nickel (nickel composite hydroxide). The nickel composite hydroxide may contain at least one or more of cobalt, aluminum and manganese in addition to nickel. As the nickel composite hydroxide, for example, nickel cobalt composite hydroxide, nickel cobalt aluminum composite hydroxide, nickel cobalt manganese composite hydroxide and the like are used. Further, the nickel composite hydroxide may contain elements such as molybdenum, tungsten, silicon, boron, niobium, vanadium, and titanium.

The method for producing a hydroxide containing nickel is not particularly limited, but for example, a crystallization method can be used. The composition of the nickel-containing hydroxide obtained by the crystallization method becomes uniform in the entire particles, and the composition of the finally obtained positive electrode active material also becomes uniform.

Hereinafter, a method for producing a nickel-cobalt composite hydroxide will be described as an example of a method for producing a nickel-containing hydroxide. The nickel-cobalt composite hydroxide uses, for example, an alkaline aqueous solution in the presence of a complexing agent such as an ammonium ion feeder while stirring an aqueous solution containing nickel (Ni), cobalt (Co), and any metal M. It can be produced by neutralizing with using and carrying out a crystallization reaction. The nickel-cobalt composite hydroxide obtained by the crystallization method is composed of secondary particles in which a plurality of primary particles are aggregated, and a positive electrode active material obtained by using the nickel-cobalt composite hydroxide particles as a precursor is also available. , It is composed of secondary particles in which a plurality of primary particles are aggregated.

As the metal salt used when preparing the aqueous solution containing nickel (Ni), cobalt (Co), and any metal M, for example, sulfate, nitrate, chloride, or the like can be used.

When the nickel composite hydroxide is a nickel cobalt aluminum composite hydroxide, for example, a complexing agent such as an ammonium ion feeder is stirred while stirring an aqueous solution containing nickel (Ni), cobalt (Co) and aluminum (Al). It can be produced by performing a crystallization reaction of neutralizing with an aqueous alkaline solution in the presence of.

When the nickel composite hydroxide contains the metal element M, for example, it may be crystallized together with Ni and Co in a crystallization reaction and uniformly dispersed in the nickel composite hydroxide, or nickel composite hydroxylation. After forming the substance by crystallization, the surface of the obtained nickel composite oxide particles may be coated, or the compound may be added and mixed at the same time as the addition of the compound containing lithium.

(Oxide containing nickel)
Oxides containing nickel include nickel oxides and oxides containing nickel and metals other than nickel (nickel composite oxides). The nickel composite oxide may contain at least one or more of cobalt, aluminum and manganese in addition to nickel. As the nickel composite oxide, for example, a nickel cobalt composite oxide, a nickel cobalt aluminum composite oxide, a nickel cobalt manganese composite oxide, or the like is used. The nickel composite oxide may also contain elements such as molybdenum, tungsten, silicon, boron, niobium, vanadium, and titanium.

The nickel-containing oxide can be obtained, for example, by oxidizing the nickel-containing hydroxide described above.

(Compound containing lithium)
A compound containing lithium means a compound containing lithium. The compound containing lithium is not particularly limited, and known compounds containing lithium can be used, and for example, lithium hydroxide, lithium nitrate, lithium carbonate, lithium acetate, or a mixture thereof can be used. Among these, lithium hydroxide and lithium carbonate are preferably used.

(Lithium mixture)
Mixing of a compound containing nickel and a compound containing lithium is the total number of atoms of metal elements (including nickel) in the compound containing nickel (Me) and the number of atoms of lithium in the compound containing lithium (Li). The ratio (Li / Me ratio) to and is, for example, 0.95 or more and 1.10 or less, preferably 1.00 or more and 1.05 or less, and more preferably 1.01 or more and 1.03 or less. It is done to be. When the Li / Me ratio is less than the above range, some nickel composite oxides may remain without reacting and sufficient battery performance may not be obtained. Further, when the Li / Me ratio exceeds the above range, sintering is promoted and the fired product becomes hard and difficult to crush, or the particle size and crystallite diameter of the positive electrode active material become large and sufficient battery performance. May not be obtained.

Since the Li / Me ratio does not change substantially before and after the firing step (step S20) described later, the Li / Me ratio in the lithium mixture is almost maintained even in the lithium nickel composite oxide. Therefore, the mixture of the compound containing nickel and the compound containing lithium can be mixed so as to have the same Li / Me ratio in the lithium nickel composite oxide to be obtained. The Li / Me ratio can be appropriately selected from appropriate values according to the battery characteristics required for the secondary battery, the configuration of the secondary battery, and the like.

A general mixer can be used for mixing, and for example, a shaker mixer, a ladyge mixer, a juria mixer, a V blender, or the like can be used. Further, this mixing may be sufficiently mixed to the extent that the skeleton of the compound containing nickel is not destroyed. If the mixing is not sufficient, the Li / Me ratio may vary among the individual particles, and problems such as insufficient battery characteristics may occur.

(binder)
The lithium mixture may contain a binder. When a binder is included, the moldability of the lithium mixture is improved, and molded bodies having various shapes can be easily formed. As the binder, a known binder can be used, and for example, polyvinyl alcohol, polyacrylamide, carboxymethyl cellulose and the like can be used. Among these, it is preferable to use polyvinyl alcohol. The lithium mixture does not have to contain a binder.

(Manufacturing method of molded product)
Then, the powder of the lithium mixture is molded to obtain a molded product. The apparatus for producing the molded product is not particularly limited as long as it can pressurize the powder of the lithium mixture, and for example, a pressing apparatus such as a tableting machine or a molding machine can be used.

The shape of the molded body is not particularly limited, and when a plurality of molded bodies are supplied to the vertical furnace, a gap is formed between the molded bodies to the extent that the reaction gas and the generated gas can flow. It may have a spherical shape or a tablet-like shape such as a tablet.

The size of the molded product is not particularly limited, but the maximum distance between any two points on the outer shape of the molded product may be 1 mm, preferably 5 mm or more. When a spherical or tablet-shaped molded product is used, it is preferable that the length, width, and height are each 5 mm or more, for example. When the maximum distance between the above two points is within the above range, the compact can be efficiently fired, the productivity can be improved, and the compression molding using a tableting machine, a molding machine, or the like can be performed. A high-strength molded product can be easily produced, and the collapse of the molded product during firing can be suppressed. On the other hand, when the maximum distance between the two points is less than 1 mm, it is difficult to mold using a locking machine, a molding machine, or the like, and it is difficult to manufacture a molded product having high strength. If the strength of the molded body is not sufficient, the molded body collapses in the furnace during firing and becomes fine powder (about 100 μm or less), which is blown up by the gas flow in the vertical furnace and discharged to the outside of the vertical furnace together with the exhaust gas. This may result in loss of the molded product.

Further, the upper limit of the maximum distance of any two points on the outer shape of the molded body is preferably 1/3 or less, more preferably 1/5 or less of the inner diameter of the vertical furnace (inner diameter of the core tube). .. When a spherical or tablet-shaped molded body is used, for example, it is more preferable that the length, width, and height are each 1/5 or less of the inner diameter of the core tube.

The apparatus for producing the molded product is not particularly limited as long as it can pressurize the powder of the lithium mixture, and for example, a lock press or a briquette machine can be used.

The hardness of the molded product shall be such that it will not be disassembled (collapsed) into powder while moving (descending) in the vertical furnace. On the other hand, if the molded product is too hard, the crushing efficiency deteriorates when the molded product is crushed (crushed) using a crusher or the like after firing. Is preferable.

The density of the molded body is preferably 1.5 g / cm ³ or more and 2.5 g / cm ³ or less, and more preferably 1.8 g / cm ³ or more and 2.2 g / cm ³ or less. When the density of the molded product is within the above range, it has sufficient strength even if it does not contain a binder, has excellent crushability, and is excellent in productivity.

(2) Manufacturing Equipment Next, an example of the manufacturing equipment used in the manufacturing method of the present embodiment will be described. As shown in FIG. 2, the manufacturing apparatus 1 used in the manufacturing method of the present embodiment includes a vertical furnace 10 for firing the molded body C. In the present embodiment, as an example of the manufacturing apparatus 1, the manufacturing apparatus 1 shown in FIG. 2 will be described as an example, but the manufacturing apparatus 1 has an arbitrary configuration as long as it is an apparatus including the vertical furnace 10.

When the molded body C is fired in the vertical furnace 10, the molded body C before firing can be supplied into the furnace by the natural dropping action of the molded body C. Therefore, as compared with the horizontal continuous firing furnace, With a simpler configuration, the compact C can be easily supplied to the furnace without requiring power (line).

The manufacturing apparatus 1 shown in FIG. 2 includes a vertical furnace 10, a molded body supply device 30, a molded body discharging device 40, and a control device 50. The molded body supply device 30 is arranged above the vertical furnace 10 and supplies the molded body C before firing from the upper part of the vertical furnace 10. The molded body discharging device 40 is arranged below the vertical furnace 10 and discharges the molded body C in the vertical furnace 10. The control device 50 (including the power supply) controls each part of the manufacturing device 1. For example, the control device 50 controls the vertical furnace 10, the molded body supply device 30, and the molded body discharging device 40 in conjunction with each other.

The vertical furnace 10 includes a core tube 11, a heater 12 for heating the core tube 11, a temperature sensor 13 for measuring the temperature of the core tube 11, a heat insulating material 14 for covering the core tube 11 and the heater 12, and a heat insulating material 14. A metal outer shell 15 is provided on the outside of the vertical furnace 10 and surrounds each part of the vertical reactor 10. The vertical furnace 10 fires the molded body C at a predetermined temperature in the core tube 11 (heating zone) heated by the heater 12. Further, the vertical furnace 10 may be provided with a cooling zone 16 for cooling the molded body C after firing (baked) below (downstream) the heating zone.

The core tube 11 has a cylindrical (tubular) shape and has an inside of a furnace capable of holding an object to be fired. The inside of the core tube 11 can be filled with an object to be fired such as a molded body C. In the vertical furnace 10, the molded body C is filled inside the core tube 11, and the molded body C is fired by heating the core tube 11 with the heater 12.

The core tube 11 is made of a material that has heat resistance at the firing temperature and does not react with the components constituting the molded body at the firing temperature. For example, the core tube 11 is appropriately selected from a metal tube such as a stainless steel tube; a ceramic tube such as alumina and mullite;

The diameter (inner diameter) of the core tube 11 is not limited, but is preferably 50 mm or more and 500 mm or less, and more preferably 100 mm or more and 300 mm or less. When the diameter of the core tube 11 exceeds 500 mm, the temperature of the molded body C located near the center of the core tube 11 does not reach the desired firing temperature, which may result in insufficient firing. Further, when the diameter of the core tube 11 is less than 50 mm, the filling capacity of the molded body C is reduced, so that the productivity of firing is deteriorated.

The core tube 11 is connected to the inside of the core tube 11 (inside the furnace) where the upper part and the lower part are opened and firing is performed, for example. The molded body C to be fired is supplied from the upper part of the core tube 11. The lower part of the core tube 11 is used for discharging (carrying out) the molded body C after firing. A shutter (not shown) that can be opened and closed may be provided at the upper part and the lower part of the core tube 11, respectively.

The heater 12 is arranged so as to surround the core tube 11 and heats the core tube 11. A heating zone is formed inside the core tube 11 heated by the heater 12, and the molded body C is fired in the heating zone. The heater 12 is not particularly limited, but for example, an iron chromium heater, a nichrome heater, a silicon carbide heater, a nisilicate molybdenum heater, a graphite heater, or the like can be adopted. The heater 12 is connected to the control device 50, and the operation (degree) of heating is controlled by the control device 50.

As the temperature sensor 13, various detectors such as a thermocouple and an infrared radiation thermometer can be appropriately selected. The arrangement position and number of the temperature sensors 13 are not particularly limited and are arbitrary. For example, the temperature sensor 13 may be arranged so as to be inserted into the core tube 11 from the upper part of the core tube 11 or from the side surface of the core tube 11 as in the example of FIG. For example, the number of temperature sensors 13 may be one or a plurality as shown in the example of FIG. The temperature sensor 13 is connected to the control device 50, and the measurement result is sent to the control device 50.

The heat insulating material 14 is arranged so as to cover the core tube 11 and the heater 12, and insulates the heat from the core tube 11. The heat insulating material 14 is not particularly limited, and for example, a ceramic fiber plate, refractory bricks, and the like are appropriately selected.

A cooling zone 16 for cooling the molded body C (after firing) is provided below the heater 12 (heating zone) of the core tube 11. The cooling zone 16 is provided in a connection portion 24 (connector) connected to the lower part of the core tube 11. The connecting portion 24 is configured to accommodate the molded body C after firing.

In the cooling zone 16, as will be described later, the reaction gas (not shown) supplied from below the cooling zone 16 and the molded body C after firing come into countercurrent contact with each other to form the molded body C after firing. Cooling. In the case of this configuration, cooling of the molded body C after firing can be promoted, and the temperature of the reaction gas is raised by heat exchange by bringing the reaction gas into contact with the molded body C after firing to raise the temperature of the core tube. Since it can be introduced into the inside of 11 (heating zone), the firing reaction of the molded body C can be stabilized and promoted. Further, as will be described later, the reaction gas may be exhausted from above the heating zone together with the generated gas generated from the molded body C.

The cooling zone 16 may be configured such that, for example, a cooling device such as a water cooling jacket is arranged in the core tube 11 (lower part) or the connection portion 24 to accelerate the cooling of the molded body C after firing. However, it may be configured to be cooled by the natural heat dissipation action of the molded body C after firing. Further, the cooling zone 16 may be configured to control and cool the temperature of the molded body C after firing. Further, it is arbitrary whether or not the manufacturing apparatus 1 includes the cooling zone 16.

Further, a molded body supply device 30 is connected to the upper portion (upper, upstream) of the vertical furnace 10 (connection portion 20). The molded body supply device 30 continuously or intermittently supplies a predetermined amount of the plurality of molded bodies C (molded bodies C before firing) from the upper part of the core tube 11 into the furnace. The molded body supply device 30 supplies the molded body C from the upper part of the core tube 11 into the furnace by using the free fall action due to gravity. As described above, by supplying a plurality of molded bodies C into the furnace (inside the vertical furnace 10) by the molded body supply device 30 or the like, the molded bodies C can be efficiently manufactured in a shorter time than the conventional manufacturing method. Can be fired. As described above, when the manufacturing apparatus 1 includes the molded body supply device 30 for supplying the molded body C to the vertical furnace 10, the production of the lithium nickel composite oxide can be made more efficient.

The molded body supply device 30 may adjust the supply amount and supply timing of the molded body C (molded body C before firing) under the control of the control device 50. For example, the molded body supply device 30 is provided with a weight scale such as a load cell inside, and by monitoring the weight of the molded body C supplied to the core tube 11, a predetermined amount of the plurality of molded bodies C is transferred to the core tube 11. It may be configured to adjust the supply amount. The molded body supply device 30 of the present embodiment adjusts the supply amount and supply timing of the molded body C before firing under the control of the control device 50, and automatically supplies the molded body C into the vertical furnace 10. As such a molded body feeder 30, a vibration feeder, a screw feeder, a table feeder (circle feeder) and the like can be applied, and among these, a table feeder (circle feeder) is applicable from the viewpoint of supply stability of the molded body C. ) Is more suitable.

For example, the molded body supply device 30 is a table feeder, and is a predetermined storage unit 31 for accommodating the pre-firing molded body C supplied to the vertical furnace 10 and a pre-firing molded body C housed in the accommodating unit 31. A supply unit 32 for supplying an amount to the vertical furnace 10 is provided. The supply unit 32 is connected to the upper part of the core tube 11 via the connection unit 20 (connector).

As shown in FIG. 2, as the molded body supply device 30, a molded body supply device 30 that supplies a pre-manufactured molded body may be used separately from the device for molding the molded body (such as a tableting machine). However, it may be used as a molded body supply device 30 having an apparatus (molded article manufacturing apparatus) used when manufacturing a molded article such as a tableting machine.

It is arbitrary whether or not the manufacturing apparatus 1 includes the molded body supply apparatus 30. For example, the manufacturing apparatus 1 does not have to include the molded body supply device 30, and in this case, for example, the manufacturing apparatus 1 causes a predetermined amount of a plurality of molded bodies C from the upper part of the core tube 11 by human work. It may be configured to continuously or intermittently supply the inside of the furnace.

A molded body discharging device 40 is connected to the lower part (downward, downstream) of the vertical furnace 10 (connecting portion 24). The fired molded body C fired in the core tube 11 is discharged from the lower part of the vertical furnace 10 to the molded body discharging device 40 via the connecting portion 24. As a result, the molded body C in the vertical furnace 10 (inside the core tube 11) moves downward due to the free fall action due to gravity.

The molded body discharging device 40 continuously or intermittently discharges a predetermined amount of a plurality of molded bodies C (fired molded bodies) from the lower part of the core tube 11 (vertical furnace 10) to the outside. The molded body discharging device 40 discharges the molded body C from the lower part of the core tube 11 to the outside by using the free fall action by gravity. The molded body discharging device 40 automatically discharges a predetermined amount of a plurality of molded bodies C (fired molded bodies) to the outside of the vertical furnace 10 at a predetermined timing under the control of the control device 50. As described above, when the manufacturing apparatus 1 includes the molded body discharging device 40 for continuously or intermittently automatically discharging the calcined molded body C, the production of the lithium nickel composite oxide can be made more efficient.

The molded body discharging device 40 preferably discharges a plurality of fired molded bodies C in a predetermined amount. For example, the molded body discharging device 40 includes a weight measuring unit for measuring the weight of the molded body C discharged after firing, monitors the weight of the molded body C discharged from the core tube 11 after firing, and after firing. The discharge amount of the molded body C of the above is adjusted. The molded body discharging device 40 controls the acceptance of the fired molded body C at a portion such as a portion where the molded body C is received from the core tube 11 (eg, acceptance amount, acceptance speed, acceptance timing, etc.). May have a possible configuration. A vibration feeder, a screw feeder, a circle feeder, or the like can be applied as such a molded body discharging device 40, and among these, a table feeder (circle feeder) is used from the viewpoint of discharging stability of the molded body C after firing. Is more suitable.

For example, the molded body discharging device 40 is a table feeder and includes a receiving unit 41 used for introducing the fired molded body C discharged from the vertical furnace 10 and a discharging unit 42 for discharging the molded body C. .. The receiving portion 41 is connected to the core tube 11 via the connecting portion 24. When the fired molded body C is collected in the storage unit 26 that stores (accommodates) the fired molded body C, the discharge unit 42 is connected to the storage unit 26 and the fired molded body C is stored in the storage unit 26. Discharge to.

It is arbitrary whether or not the manufacturing apparatus 1 includes the molded body discharging device 40. For example, the manufacturing apparatus 1 does not have to include the molded body discharging device 40. In this case, for example, the manufacturing apparatus 1 externally removes a predetermined amount of the fired molded body C from the core tube 11 by human work. In addition, it may be configured to discharge continuously or intermittently.

The control device 50 controls the temperature of the core tube 11 by acquiring the temperature information of the core tube 11 from the temperature sensor 13 and controlling the heater 12 based on the acquired temperature information of the core tube 11. Further, the control device 50 acquires the supply amount information of the molded body from the molded body supply device 30 and the discharge amount information of the molded body from the molded body discharge device 40, and the supply amount information and the discharge amount information of the acquired molded body. By controlling the molded body supply device 30 and the molded body discharging device 40 in conjunction with each other, the amount of the molded body C in the core tube 11 and the residence time of the molded body C are controlled.

The plurality of molded bodies C supplied into the core tube 11 of the vertical furnace 10 described above proceed with the sintering reaction while being in contact with the reaction gas and heat supplied from the manufacturing apparatus 1 in the heating zone.

As shown in FIG. 2, in the manufacturing apparatus 1, the reaction gas is supplied from the reaction gas supply port 27 installed below the heating zone and exhausted from the gas discharge port 28 installed above the heating zone. As a result, the reaction gas and the generated gas generated from the molded body C can uniformly flow in the same direction through the voids between the molded bodies C, and the reaction gas and heat are supplied to each molded body and generated. Desorption of gas is facilitated. This improves the firing efficiency, enables a more uniform reaction of the lithium mixture, and shortens the firing time.

For example, the reaction gas supply port 27 is provided in the molded body discharging device 40. The reaction gas supplied from the reaction gas supply port 27 of the molded body discharging device 40 is guided to the vicinity of the center of the cross section of the connecting portion 24, passes through the connecting portion 24, and is introduced into the core tube 11 from the lower part of the core tube 11. Will be done. At this time, the fired molded body C housed in the cooling zone 16 comes into countercurrent contact with the reaction gas, so that the fired molded body C is cooled.

The reaction gas introduced into the core tube 11 flows from the lower side to the upper side of the core tube 11. The molded body C in the core tube 11 comes into contact with the gas flow flowing from the lower side to the upper side of the core tube 11 to receive heat and reaction gas. At the same time, the generated gas generated during firing from the molded body C can be separated from the molded body C and discharged to this gas stream.

The reaction gas is discharged from the gas discharge port 28 provided above the vertical furnace 10 (connection portion 20). The exhaust gas discharged from the gas discharge port 28 is guided to an exhaust gas treatment device (not shown) for treatment via a pipe or the like.

The method for supplying the reaction gas is not particularly limited and may be any method. Further, the reaction gas supply port 27 may be provided in addition to the molded body discharging device 40. Further, the gas discharge port 28 may be provided in addition to the connection portion 20. For example, as in Patent Document 3 above, the reaction gas and the raw material may be supplied into the vertical furnace from the upper part of the vertical furnace. However, in this case, the reaction gas does not spread throughout the vertical furnace due to a gas passage in the filling portion of the raw material mixture in the furnace, and the supply of the reaction gas and the desorption of the generated gas are insufficient. The sintering reaction may not be sufficient.

Further, the manufacturing apparatus 1 may include a crushing apparatus 60. The crushing device 60 crushes the fired molded product C into a lithium nickel composite oxide powder. The crushing device 60 is not particularly limited, but for example, a known device such as a ball mill, a jet mill, a roll crusher, or a pin mill can be used.

Returning to the description of FIG. 1, the manufacturing method of the present embodiment will be described below.
(3) Supply of molded product (step S10)
Step S10 is performed, for example, by continuously or intermittently supplying the above-mentioned plurality of molded bodies C from the upper part of the vertical furnace 10 into the vertical furnace 10 (inside the core tube 11). The molded body C may be supplied to the vertical furnace 10 by using the molded body supply device 30 shown in FIG. The timing of supplying the molded body C to the vertical furnace 10 is not particularly limited and is arbitrary, and a predetermined amount of the molded body C can be continuously or intermittently supplied in a plurality of times. The timing for supplying the molded body C is appropriately determined, for example, by the firing time or the like. The amount supplied to the molded body C by the molded body supply device 30 is not particularly limited and is arbitrary. For example, this amount is appropriately determined depending on the capacity of the core tube 11 and the discharge amount of the molded body C. To.

(4) Firing of the molded product (step S20)
Next, in the manufacturing method of the present embodiment, in step S20, the molded product is fired in a vertical furnace.

Step S20 is carried out, for example, by firing the molded body C supplied into the vertical furnace 10 (inside the core tube 11) of the manufacturing apparatus 1 of FIG. 2 in a heating zone in step S10. The temperature at which the molded body C is fired (firing temperature) is appropriately set according to the composition of the lithium mixture constituting the molded body C, and is not particularly limited, but is, for example, 650 ° C. or higher and 1000 ° C. or lower. When the firing temperature is less than 650 ° C., lithium is not sufficiently diffused, unreacted lithium compounds remain, and the crystal structure of the lithium nickel composite oxide is not sufficiently arranged, resulting in lithium nickel composite oxidation. Objects may not exhibit sufficient battery characteristics. On the other hand, when the firing temperature exceeds 1000 ° C., abnormal grain growth may occur between the lithium nickel composite oxide particles, and the obtained lithium nickel composite oxide may not exhibit sufficient battery characteristics.

Further, the firing time of the molded body C can be appropriately adjusted depending on the composition of the lithium mixture constituting the molded body C. Since the molded body C can be efficiently fired in the production method of the present embodiment, a lithium nickel composite oxide having high crystallinity can be obtained in a shorter firing time than the conventional production method.

Further, in the present embodiment, at the time of firing in step S20, as described above, the reaction gas is supplied from below the heating zone, brought into contact with the molded body C in the vertical furnace 10, and exhausted from above the heating zone. You may. In this case, the reaction gas and the generated gas generated from the molded body can uniformly flow in the same direction through the voids between the molded bodies C, and the reaction gas and heat are supplied to each molded body C and generated. Desorption of gas is facilitated. This improves the firing efficiency, enables a more uniform reaction of the lithium mixture, and shortens the firing time.

(5) Discharging the molded product (step S30)
Next, in the manufacturing method of the present embodiment, in step S30, the plurality of fired compacts are continuously or intermittently discharged from the lower part in the vertical furnace to the outside.

Step S30 is performed, for example, by continuously or intermittently discharging the fired plurality of molded bodies C from the lower part of the core tube 11 (vertical furnace 10) to the outside. The molded body C may be discharged from the vertical furnace 10 by using the molded body discharging device 40 of FIG. The fired plurality of molded bodies C are discharged to, for example, the storage unit 26. When the fired molded product C is discharged to a predetermined place such as a storage unit 26 as in the manufacturing method of the present embodiment, the next step regarding the fired molded product C can be easily performed.

The timing and discharge amount of the plurality of fired molded bodies C continuously or intermittently supplied from the lower part of the core tube 11 (vertical furnace 10) to the outside of the vertical furnace 10 are not particularly limited. , And is appropriately determined, for example, according to the timing and amount of supply of the molded body C from the molded body supply device 30. When the fired molded product C is continuously or intermittently discharged, the production of the lithium nickel composite oxide can be made more efficient, and above all, when the molded product C is automatically discharged using the above-mentioned molded body discharging device 40 or the like. , Can be made more efficient.

Further, in the manufacturing method of the present embodiment, the firing of the molded body C in step S20 is performed by step S10 while discharging the molded body C that has been fired in step S30 from the lower part in the vertical furnace 10 during the firing process. By supplying the molded body C before firing from the upper part of the vertical furnace 10 into the vertical furnace 10 (inside the core tube 11), the molded body C may be fired while moving from above to below. That is, in the manufacturing method of the present embodiment, steps S10, S20, and S30 may be interlocked (synchronized). Thereby, the production of the lithium nickel composite oxide can be made more efficient. In the firing of the molded body C in step S20, the molded body C is continuously moved downward in the vertical furnace 10 (inside the core tube 11) by continuously performing steps S10, S20, and S30. The molded product C may be intermittently fired in the vertical furnace 10 (inside the core tube 11) by intermittently performing steps S10, S20, and S30 at predetermined timings. You may bake while moving. The moving speed when the molded body C is continuously moved and the predetermined timing for intermittently moving the molded body C downward are, for example, the firing time of the molded body C (the molded body in the core tube 11). It is set according to the residence time of C). In the manufacturing apparatus 1 of the present embodiment, the moving speed and the moving timing are controlled by controlling the molded body supply device 30, the molded body discharging device 40, and the heater 12 by the control device 50, and the above steps are taken. The molded body C of S20 is fired. In the firing of the molded body C in step S20, the timing of discharging the fired molded body C in step S30 and the timing of supplying the molded body C before firing in step S10 may be simultaneous. It may be different.

Further, in the manufacturing method of the present embodiment, as described above, the fired molded body C discharged from the vertical furnace 10 is supplied to the core tube 11 downstream (lower part) of the core tube 11 by the reaction gas. It may be cooled.

(6) Crushing of the molded product (step S40)
Next, in the manufacturing method of the present embodiment, in step S40, the molded product discharged from the lower part in the vertical furnace to the outside is crushed to obtain a powder of the lithium nickel composite oxide.

For example, in step S40, the fired compact C is crushed by the crushing device 60 described above to obtain a powder of the lithium nickel composite oxide. The timing of performing step S40 is not particularly limited and may be arbitrary, and may be performed at the same time as steps S10, S20, and S30, or may be performed at a timing different from that of steps S10, S20, and S30.

As described above, according to the method for producing a lithium nickel composite oxide of the present embodiment, the uniform reaction of the lithium mixture and the firing time can be shortened, thereby improving the productivity. Further, according to the above-mentioned manufacturing method, since consumables such as a crucible or a sack are not used, the manufacturing cost can be reduced.

[Second Embodiment]
2. 2. The second embodiment of the method for producing a lithium nickel composite oxide will be described with reference to FIGS. 3 (A) to 3 (C) as appropriate. In the present embodiment, the same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.

In the manufacturing method of the second embodiment, as shown in FIGS. 3A to 3B, the ceramic balls S are placed in the vertical furnace 10 before the molded body C is supplied into the vertical furnace 10. It is supplied (step S50) and heated until the inside of the vertical furnace 10 reaches the firing temperature (step S51), and after the inside of the vertical furnace 10 reaches the firing temperature, the ceramic balls S are placed in the vertical furnace. The plurality of molded bodies C are supplied from the upper part of the vertical furnace 10 into the furnace (step S61 (S10)) while being discharged from the lower part of the 10 to the outside of the furnace (step S60).

Generally, when a powder raw material is fired in a vertical furnace, a dummy powder raw material is filled in the furnace in preparation for firing to heat the vertical furnace, and the temperature inside the furnace and the temperature of the powder raw material in the furnace are used. When the temperature reaches the target temperature, the powder raw material is newly put into the vertical furnace and firing is started. The dummy powder raw material used at the time of preparing for firing becomes a loss and causes a cost increase.

In the manufacturing method of the second embodiment, since the ceramic balls S are used instead of the dummy powder raw material before the supply of the molded body C to the vertical furnace 10 is started, the cost of the dummy raw material is reduced. , Manufacturing cost can be reduced.

The ceramic ball S is not particularly limited, and a ceramic ball S made of a known heat-resistant material can be used, and can be appropriately selected from alumina and zirconia.

The size of the ceramic ball S is not particularly limited, but it is preferably the same as or about the same as the size of the molded body C. If a ceramic ball S having the same size as the molded body C cannot be obtained, a commercially available product having the closest size may be selected.

The supply amount of the ceramic balls S is, for example, an amount that can be filled up to a height similar to the filling height of the molded body C in the core tube 11.

After the inside of the vertical furnace 10 reaches the firing temperature, the ceramic balls S are discharged from the lower part of the vertical furnace 10 to the outside of the furnace (step S60), and the plurality of molded bodies C are discharged from the upper part of the vertical furnace 10. By supplying into the furnace (step S61 (S10)), the ceramic balls S are sequentially discharged from the molded body discharging device 40. Then, as shown in FIG. 3C, by supplying the molded body C instead of the ceramic balls S, a mixture of the ceramic balls S and the molded body C is discharged from the molded body discharging device 40. .. After all the ceramic balls S are discharged, only the molded body C is discharged until the firing of the molded body C is completed.

Further, in the manufacturing method of the present embodiment, as shown in FIG. 3C, the ceramic balls S discharged to the outside of the vertical furnace 10 and the molded body C are collected together (step S70) and recovered. Shaking the recovered material to crush the molded body C (step S71) and sieving the crushed molded body C to separate it from the ceramic balls S and recovering it (step S72). Be prepared.

For example, the mixture of the ceramic balls S recovered in the storage unit 26 and the calcined compact C is put into a sieve having a size in which the ceramic balls S remain on the sieve and shaken. When shaken with a sieve, the ceramic ball S and the molded body C and / or a plurality of molded bodies C collide with each other. At this time, the molded body C is crushed, and the molded body C smaller than the opening of the sieve falls under the sieve. The ceramic ball S remains on the sieve because it is harder to crush than the molded product. Then, by recovering under the sieve, the molded body C can be separated from the ceramic ball S and recovered.

The recovered molded product C may be further supplied to the above-mentioned crushing step (step S40) and crushed. The recovered lithium-nickel composite oxide (calcined molded product C in which at least a part thereof is crushed) can be suitably used as a positive electrode active material for a non-aqueous electrolyte secondary battery. On the other hand, the ceramic ball S on the sieve may be reused in the preparatory stage at the time of the next firing.

Further, when the firing of all the molded bodies C supplied to the vertical furnace 10 is completed, the ceramic balls S may be supplied again from the molded body supply device 30 into the core tube 11 instead of the molded body C. .. In this case, the firing is terminated when the discharge of the molded body C from the molded body discharging device 40 is completed. Therefore, when the molded body C is fired next time, the ceramic balls S are already contained in the core tube 11. Since it is in a filled state, the start-up time of the vertical furnace 10 can be shortened. The molded body C and the ceramic ball S before the completion of firing can be separated by the above-mentioned sieving. The manufacturing method of the present embodiment is the same as the manufacturing method of the first embodiment except for the above.

[Third Embodiment]
3. 3. Method for manufacturing a non-aqueous electrolyte secondary battery The method for manufacturing a non-aqueous electrolyte secondary battery according to the present embodiment (hereinafter, also referred to as “secondary battery manufacturing method”) is a lithium nickel composite obtained by the above-mentioned manufacturing method. It comprises using an oxide as a positive electrode active material to obtain a positive electrode, and using the obtained positive electrode, negative electrode, and non-aqueous electrolyte to obtain a non-aqueous electrolyte secondary battery. The secondary battery obtained by the manufacturing method according to the present embodiment may be provided with at least a positive electrode, a negative electrode and a non-aqueous electrolyte, and may be provided with a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte solution, and may be provided with a positive electrode, a negative electrode and a non-aqueous electrolyte solution. , And a solid electrolyte may be provided. Further, the secondary battery may be composed of the same components as the known lithium ion secondary battery.

Hereinafter, as an example of the method for manufacturing the secondary battery according to the present embodiment, each constituent material of the secondary battery using the non-aqueous electrolyte solution and the manufacturing method thereof will be described. It should be noted that the embodiments described below are merely examples, and the method for manufacturing a secondary battery is modified and improved based on the embodiments described in the present specification based on the knowledge of those skilled in the art. It can be carried out in the above-mentioned form. Further, the secondary battery obtained by the manufacturing method according to the present embodiment is not particularly limited in its use.

(Positive electrode)
The positive electrode contains the positive electrode active material according to the present embodiment described above. The positive electrode can be produced, for example, as follows.

First, the above-mentioned positive electrode active material, conductive material, and binder are mixed, and if necessary, activated carbon, a solvent for viscosity adjustment, etc. are added, and the mixture is kneaded to prepare a positive electrode mixture paste. ..

The mixing ratio of each material in the positive electrode mixture paste is not particularly limited, and can be appropriately adjusted according to the required performance of the secondary battery. The mixing ratio of the materials can be in the same range as that of the positive electrode of a known non-aqueous electrolyte secondary battery. For example, when the total mass of the solid content of the positive electrode mixture excluding the solvent is 100 parts by mass, the positive electrode is used. The content of the active material can be 60 parts by mass or more and 95 parts by mass or less, the content of the conductive material can be 1 part by mass or more and 20 parts by mass or less, and the content of the binder can be 1 part by mass or more and 20 parts by mass or less. ..

The obtained positive electrode mixture paste can be applied to, for example, the surface of a current collector made of aluminum foil, dried, and the solvent can be scattered to produce a sheet-shaped positive electrode. If necessary, pressurization may be performed by a roll press or the like in order to increase the electrode density.

The produced sheet-shaped positive electrode can be cut into an appropriate size according to the target battery and used for the production of the battery. However, the method for producing the positive electrode is not limited to the above-exemplified one, and other methods may be used.

As the conductive agent, for example, graphite (natural graphite, artificial graphite, expanded graphite, etc.), carbon black materials such as acetylene black, and Ketjen black can be used.

The binder plays a role of binding the active material particles, for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluororubber, ethylene propylene diene rubber, styrene butadiene, cellulose resin, and polyacrylic acid. Acids and the like can be used.

Further, if necessary, a solvent that disperses the positive electrode active material, the conductive material, and the activated carbon and dissolves the binder may be added to the positive electrode mixture. Specifically, as the solvent, an organic solvent such as N-methyl-2-pyrrolidone can be used. In addition, activated carbon can be added to the positive electrode mixture in order to increase the electric double layer capacity.

(Negative electrode)
As the negative electrode, metallic lithium, a lithium alloy, or the like can be used. The negative electrode is made of a negative electrode mixture, which is made by mixing a binder with a negative electrode active material capable of occluding and desorbing lithium ions and adding an appropriate solvent to form a paste, on the surface of a metal leaf current collector such as copper. It can be applied to, dried, and if necessary, compressed to increase the electrode density.

As the negative electrode active material, for example, an organic compound fired body such as natural graphite, artificial graphite, or phenol resin, or a powdery body of a carbon substance such as coke can be used.

As the negative electrode binder, a fluororesin such as PVDF can be used as in the positive electrode, and as a solvent for dispersing these active substances and the binder, an organic solvent such as N-methyl-2-pyrrolidone is used. Can be used.

(Separator)
A separator is sandwiched between the positive electrode and the negative electrode. The separator separates the positive electrode and the negative electrode and retains an electrolyte, and is a thin film containing a resin such as polyethylene or polypropylene, and a film having a large number of fine pores can be used.

(Non-aqueous electrolyte solution)
The non-aqueous electrolyte solution is obtained by dissolving a lithium salt as a supporting salt in an organic solvent.

Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and trifluoropropylene carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate and dipropyl carbonate, and tetrahydrofuran and 2-. One selected from ether compounds such as methyl tetrahydrofuran and dimethoxyethane, sulfur compounds such as ethylmethyl sulfone and butane sulton, and phosphorus compounds such as triethyl phosphate and trioctyl phosphate is used alone or in combination of two or more. be able to.

As the supporting salt, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , etc., and a composite salt thereof can be used.

Further, the non-aqueous electrolyte solution may contain a radical scavenger, a surfactant, a flame retardant and the like.

(Shape and composition of non-aqueous electrolyte secondary battery)
The shape of the secondary battery composed of the positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte solution can be various, such as a cylindrical type and a laminated type. In the secondary battery according to the present embodiment, for example, a positive electrode and a negative electrode are first laminated via a separator to obtain a laminated body (electrode), and then the obtained electrode contains a non-aqueous electrolytic solution. After invading, connect the positive electrode collector and the positive electrode terminal leading to the outside, and the negative electrode current collector and the positive electrode terminal communicating to the outside with a lead or the like, and seal the battery case. Thereby, it can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the contents of the examples.

[Example 1]
The molded product was fired in the manufacturing apparatus shown in FIG. 2, and the battery characteristics of the secondary battery using the obtained lithium nickel composite oxide as the positive electrode active material were evaluated.

First, the vertical furnace was filled with the molded product, and then heated while supplying the reaction gas. When the heating zone temperature reached 750 ° C., the supply of the molded product from the upper part of the vertical furnace and the discharge of the molded product from the lower part of the vertical furnace were started, and firing was started.

The firing was performed under the following conditions.
(Vertical furnace)
Core tube inner diameter: 150 mmφ, core tube length 2000 mm
Heating band length: 900 mm
Heating zone control temperature: 750 ° C
Cooling zone length: 900 mm
Reaction gas O ₂ : 80% by volume, 15 L / min
Mold filling height: 1800 mm from the bottom of the core tube
Mold supply device: Table feeder Mold discharge device: Table feeder Mold supply speed: 4.0 kg / h
Vertical furnace residence time of molded product: 8 hours

(Molded body)
A lithium mixture containing the following nickel composite hydroxide powder and lithium as a raw material was made into a molded body by a tableting machine and used for firing in a vertical furnace.

Nickel composite hydroxide powder: Ni _0.8 Co _0.1 Al _0.1 (OH) _2.0
Powder powder of compounds containing lithium: LiOH
Molar ratio of nickel composite hydroxide to lithium-containing compound: 2: 1
Shape of molded body: Sphere with a diameter of 10 mm Diameter of molded body: 2.0 g / cm ³
Mold volume: 100 kg (31 kg of which was used for filling when the temperature of the vertical furnace was raised)

Of the compacts discharged from the vertical furnace, damage was observed in about 30% of the compacts supplied and filled in the vertical furnace before the start of firing. The molded product supplied and filled in the vertical furnace before the start of firing and discharged from the vertical furnace after the start of firing was screened for the damaged molded product to remove the molded product under the sieve. A new molded body in the same amount as the molded body under the sieve can be added to the molded body on the sieve and reused as a molded body for filling at the start of the next firing.

On the other hand, no damage was observed in the molded body supplied to the vertical furnace after the start of firing and discharged from the vertical furnace after firing. Of the calcined molded bodies discharged from the vertical furnace, the molded bodies supplied to the vertical furnace after the start of firing were used as evaluation targets for battery characteristic evaluation.

The evaluation molded body was crushed to a powder having an average particle size of 50 μm using a roll crusher and a pin mill, and this was used as a lithium nickel composite oxide to produce a button battery.

(Manufacturing and evaluation of evaluation batteries)
The evaluation of the obtained lithium-nickel composite oxide was carried out by producing a coin-type secondary battery CBA for evaluation shown in FIG. 4 by the following method and measuring the initial discharge capacity.

(Manufacturing of coin-type secondary battery CBA)
The coin-type secondary battery CBA is composed of a case CA and an electrode EL housed in the case CA. The case CA has a positive electrode can PC that is hollow and has one end opened, and a negative electrode can NC that is arranged in the opening of the positive electrode can PC. When the negative electrode can NC is arranged in the opening of the positive electrode can PC, , The space for accommodating the electrode EL is formed between the negative electrode can NC and the positive electrode can PC. The electrode EL is composed of a positive electrode PE, a separator SE, and a negative electrode NE, and is laminated in this order so that the positive electrode PE contacts the inner surface of the positive electrode can PC and the negative electrode NE contacts the inner surface of the negative electrode can NC. It is housed in CA.

The case CA is provided with a gasket GA, and the positive electrode can PC and the negative electrode can NC are fixed so as to maintain a non-contact state by the gasket GA. Further, the gasket GA also has a function of sealing the gap between the positive electrode can PC and the negative electrode can NC to hermetically and liquidally shut off the space between the inside and the outside of the case CA. Specifically, the coin-type secondary battery CBA was manufactured as follows.

The positive electrode PE (evaluation electrode) is made by mixing 52.5 mg of lithium nickel composite oxide, 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE), and press-molded to a diameter of 11 mm and a thickness of 100 μm at a pressure of 100 MPa. And made. The prepared positive electrode PE was dried in a vacuum dryer at 120 ° C. for 12 hours.

For the negative electrode NE, a graphite powder with an average particle size of about 20 μm punched into a disk shape with a diameter of 14 mm and a negative electrode sheet coated with polyvinylidene fluoride on a copper foil were used, and 1 M of LiPF ₆ was supported as the electrolytic solution. An equal amount mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) (manufactured by Toyama Yakuhin Kogyo Co., Ltd.) was used. A polyethylene porous membrane having a film thickness of 25 μm was used for the separator SE.

Using the above positive electrode PE, negative electrode NE, separator SE, and non-aqueous electrolyte solution, a coin-type secondary battery CBA was produced in a glove box having an Ar atmosphere in which the dew point was controlled to −80 ° C. or lower.

[Battery evaluation]
The initial charge / discharge capacity indicating the performance of the manufactured coin-type secondary battery CBA was evaluated as follows.
(Initial discharge capacity)
The initial discharge capacity is cut off with the current density for the positive electrode set to 0.1 mA / cm ² after the open circuit voltage OCV (Open Circuit Voltage) stabilizes after leaving it for about 24 hours after manufacturing the coin-type secondary battery CBA. The capacity when the battery was charged to a voltage of 4.3 V and discharged to a cutoff voltage of 3.0 V after a one-hour rest was defined as the initial discharge capacity.

The initial discharge capacity of the obtained secondary battery for evaluation was 233 mAh / g.

[Example 2]
Firing of a mixture of nickel composite hydroxide powder and compound powder containing lithium by the same method as in Example 1 except that ceramic balls are filled in the vertical furnace core tube instead of the molded body before the start of firing. Did.

(Ceramic ball)
Material: Alumina (alumina 99% or more)
Shape: Spherical ceramic ball with a diameter of 10 mm Amount: 80 kg

After all the ceramic balls were discharged from the vertical furnace, the molded body discharged from the vertical furnace was evaluated as a molded body for evaluation of the positive electrode material active material by the same method as in Example 1.

The ceramic balls discharged from the vertical furnace were not damaged and were in a reusable state. The initial discharge capacity of the obtained secondary battery for evaluation was 228 mAh / g.

[Comparative Example 1]
A lithium mixture similar to that used in Example 1 was put into a pot, placed in a batch-type firing furnace, and a reaction gas was supplied to the firing furnace to adjust the atmosphere inside the furnace to raise the temperature. The mixture was heated for hours and fired. After that, the heating of the firing furnace was stopped to cool the mixed powder. After cooling, the saggar was taken out from the baking furnace to obtain a baked mixed powder. This mixed powder was crushed to a powder with an average particle size of 50 μm using a roll crusher and a pin mill, and this was used as a lithium nickel composite oxide to produce a button battery by the same method as in Example 1 and evaluated. ..

The firing was performed under the following conditions.
Saggar internal dimensions: 300 mm x 400 mm x 100 mm (12 L)
Lithium mixture saggar serving amount: 12 kg
Temperature rise time: 4 hours Firing temperature: 750 ° C
Baking time: 8 hours Cooling time: 4 hours Reaction gas O ₂ : 80% by volume 15L / min

The initial discharge capacity of the obtained secondary battery for evaluation was 230 mAh / g.

(Evaluation results)
In the above-mentioned production methods of Examples 1 and 2, a lithium mixture is formed into a molded product, and then a plurality of molded products are supplied to a vertical furnace and fired to obtain a comparison with the production method of Comparative Example 1. A large amount of lithium nickel composite oxide can be obtained in a shorter firing time. In addition, the time required to start up and raise the temperature of the device can be shortened as compared with the case of using a batch type firing furnace. Further, the lithium nickel composite oxide obtained by the production methods of Examples 1 and 2 has a battery capacity equal to or higher than that of the lithium nickel composite oxide obtained by the method of Comparative Example 1. Therefore, in the production methods of Examples 1 and 2, the reaction gas and heat are sufficiently supplied to the molded product, so that the firing time is shortened and the uniform sintering reaction is promoted to obtain crystallinity. It was confirmed that an excellent lithium-nickel composite oxide could be obtained.

Further, from the evaluation results of Example 2, it is shown that even when the ceramic balls are filled in the vertical furnace core tube instead of the molded body before the firing of the molded body is started, the firing of the molded body is not adversely affected. Was done. Further, since the ceramic ball is reusable, when the ceramic ball is used in the manufacturing method of the present embodiment, it is more effective in reducing the cost.

As described above, in the method for producing a lithium-nickel composite oxide of the present invention, the uniform reaction of the lithium mixture can be promoted and the firing time can be shortened, so that the lithium-nickel composite oxidation is highly productive on an industrial scale. You can get things. Further, since the manufacturing method of the present invention does not use a saggar, the cost required for replacing the saggar can be shortened. Therefore, the manufacturing method of the present invention can be suitably used as a manufacturing method of a positive electrode active material for a secondary battery for environment-friendly automobiles such as hybrid automobiles and electric automobiles whose demand has been increasing in recent years.

The technical scope of the present invention is not limited to the embodiments described in the above-described embodiments. One or more of the requirements described in the above embodiments and the like may be omitted. Further, the requirements described in the above-described embodiments and the like can be appropriately combined. In addition, to the extent permitted by law, the disclosure of all documents cited in the above-mentioned embodiments and the like shall be incorporated as part of the description in the main text.

1 ... Manufacturing equipment 10 ... Vertical furnace (vertical furnace)
11 ... Core tube 12 ... Heater 13 ... Temperature sensor 14 ... Insulation material 15 ... Outer shell 16 ... Cooling zone 20 ... Connection (connector)
24 ... Connection part (connector)
26 ... Storage unit 27 ... Reaction gas supply port 28 ... Gas discharge port 30 ... Molded body supply device 31 ... Storage unit 32 ... Supply unit 40 ... Molded body discharge device 41 ... Receiving unit 42 ... Discharge unit 50 ... Control device 60 ... Solution Crushing device C ... Molded body S ... Ceramic ball CBA ... Coin-type secondary battery CA ... Case EL ... Electrode GA ... Gasket NC ... Negative electrode can NE ... Negative electrode OCV ... Open circuit voltage PC ... Positive electrode can PE ... Positive electrode SE ... Separator

Claims (10)

A method for producing a lithium nickel composite oxide by calcining a compound containing nickel and a compound containing lithium.
A plurality of molded bodies obtained by molding a mixture containing a powder of the nickel-containing compound and the lithium-containing compound are continuously or intermittently supplied from the upper part of the vertical furnace into the furnace. When,
In the vertical furnace, firing the molded product and
A plurality of calcined compacts are continuously or intermittently discharged from the lower part of the vertical furnace to the outside .
The molded body has a maximum distance of 5 mm or more between any two points on the outer shape.
The density of the molded product is 1.5 g / cm ³ or more and 2.5 g / cm ³ or less.
A method for producing a lithium nickel composite oxide. Firing the molded product
During the firing process, the molded body that has been fired is discharged from the lower part of the vertical furnace, and the molded body before firing is supplied from the upper part of the vertical furnace into the furnace to obtain the molded body. The method for producing a lithium nickel composite oxide according to claim 1, which comprises firing while moving from the upper side to the lower side. The lithium nickel composite according to claim 1 or 2, comprising crushing the molded body discharged from the lower part of the vertical furnace to the outside to obtain a powder of the lithium nickel composite oxide. Oxide production method. The molded body is supplied into the vertical furnace from a molded body supply device arranged above the vertical furnace.
The one according to any one of claims 1 to 3, wherein the fired molded body is discharged from the inside of the vertical furnace to a molded body discharging device arranged below the vertical furnace. The method for producing a lithium nickel composite oxide according to the above. The vertical furnace is provided with a heating zone for heating and firing the molded product in the furnace.
Any one of claims 1 to 4, wherein the reaction gas is supplied from below the heating zone, brought into contact with the molded body in the vertical furnace, and exhausted from above the heating zone. The method for producing a lithium nickel composite oxide according to the section. The vertical furnace is provided with a cooling zone for cooling the molded product below the heating zone.
The production of the lithium nickel composite oxide according to any one of claims 1 to 5, wherein the reaction gas is supplied from below the cooling zone to cool the calcined molded body. Method. A method for producing a lithium nickel composite oxide by calcining a compound containing nickel and a compound containing lithium.
A plurality of molded bodies obtained by molding a mixture containing a powder of the nickel-containing compound and the lithium-containing compound are continuously or intermittently supplied from the upper part of the vertical furnace into the furnace. When,
In the vertical furnace, firing the molded product and
A plurality of calcined compacts are continuously or intermittently discharged from the lower part of the vertical furnace to the outside.
Before supplying the molded product into the vertical furnace, the ceramic balls are supplied into the vertical furnace and heated until the temperature in the vertical furnace is reached to be fired.
After the inside of the vertical furnace reaches the firing temperature, the ceramic balls are discharged from the lower part of the vertical furnace to the outside of the furnace, and a plurality of the molded bodies are supplied from the upper part of the vertical furnace into the furnace. thing,
A method for producing a lithium nickel composite oxide, including . The ceramic balls discharged to the outside of the vertical furnace and the molded product were collected together and collected.
By shaking the recovered material to crush the molded product,
The method for producing a lithium nickel composite oxide according to claim 7, wherein the crushed molded product is sieved, separated from the ceramic balls, and recovered. The method for producing a lithium nickel composite oxide according to any one of claims 1 to 8, wherein the lithium nickel composite oxide is used as a positive electrode active material for a non-aqueous electrolyte secondary battery. To obtain a positive electrode by using the lithium nickel composite oxide produced by the production method according to any one of claims 1 to 9 as a positive electrode active material.
A method for manufacturing a non-aqueous electrolyte secondary battery, comprising obtaining a non-aqueous electrolyte secondary battery using the positive electrode, the negative electrode, and the non-aqueous electrolyte.

Images