Method for producing positive electrode active material, secondary battery and vehicle

Abstract

The present invention provides a positive electrode active material which has a large charge and discharge capacity. The present invention also provides a novel positive electrode active material. According to the present invention, a positive electrode active material is produced by: obtaining a cobalt compound (also referred to as a precursor) that contains nickel, cobalt and manganese by the use of a coprecipitation process; subsequently heating a mixture, which is obtained by mixing a lithium compound and the cobalt compound, at a first temperature, and pulverizing or crushing the mixture; subsequently heating the pulverized or crushed product at a second temperature that is higher than the first temperature; and then subjecting the resulting product to a third heating treatment after mixing with an additive. The first temperature is within the range from 400°C to 700°C (inclusive). The second temperature is within the range from 700°C (exclusive) to 1050°C (inclusive).

Description

Method for producing positive electrode active material, secondary battery, and vehicle

[0001] The present invention relates to a positive electrode active material, a secondary battery, and a method for manufacturing the same, or to a mobile information terminal and a vehicle having a secondary battery.

[0002] One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device, or a manufacturing method thereof.

[0003] In this specification, the term "semiconductor device" refers to any device that can function by utilizing semiconductor characteristics, and electro-optical devices, semiconductor circuits, and electronic devices are all included in the category of semiconductor devices.

[0004] In this specification, the term "power storage device" refers to elements and devices in general that have a power storage function, including, for example, power storage devices such as lithium ion secondary batteries (also called secondary batteries), lithium ion capacitors, and electric double layer capacitors.

[0005] In recent years, the development of lithium-ion secondary batteries, lithium-ion capacitors, air batteries, and various other power storage devices has been actively pursued. Demand for high-power, high-energy-density lithium-ion secondary batteries has rapidly expanded in conjunction with the development of the semiconductor industry, and they are now essential to the modern information society as a rechargeable energy source, as they are used in portable information terminals such as mobile phones, smartphones, and notebook computers, portable music players, digital cameras, medical devices, and next-generation clean-energy vehicles such as hybrid vehicles (HVs), electric vehicles (EVs), and plug-in hybrid vehicles (PHVs).

[0006] Patent Document 1 discloses a positive electrode active material for a lithium ion secondary battery that has a high capacity and is excellent in charge / discharge cycle performance.

[0007] WO2020 / 099978

[0008] An object of one embodiment of the present invention is to provide a positive electrode active material having a large charge / discharge capacity. Another object is to provide a positive electrode active material having a high charge / discharge voltage. Another object is to provide a positive electrode active material that is not easily deteriorated. Another object is to provide a novel positive electrode active material. Another object is to provide a secondary battery having a large charge / discharge capacity. Another object is to provide a secondary battery having a high charge / discharge voltage. Another object is to provide a secondary battery that is safe or highly reliable. Another object is to provide a secondary battery that is not easily deteriorated. Another object is to provide a secondary battery with a long life. Another object is to provide a novel secondary battery.

[0009] Another object of one embodiment of the present invention is to provide a novel substance, an active material, a power storage device, or a manufacturing method thereof.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description in the specification, drawings, and claims.

[0011] The invention relating to the method disclosed in this specification is configured such that a cobalt compound (also referred to as a precursor) containing nickel, cobalt, and manganese is obtained by coprecipitation, the cobalt compound is mixed with a lithium compound, the mixture is heated at a first temperature, the heated mixture is pulverized or crushed, and then the mixture is further heated at a second temperature that is higher than the first temperature to produce a positive electrode active material.

[0012] After the water is removed by heating at a first temperature, the mixture is heated at a second temperature higher than the first temperature, and by performing two heat treatments in total, the mixed state of the mixture is improved, and when a secondary battery is fabricated, the voids in the secondary particles can be reduced. Furthermore, by performing two heat treatments in total, the crystallinity can be improved.

[0013] The first temperature range is set to be 400°C or higher and 700°C or lower.

[0014] The second temperature range is greater than 700°C and less than or equal to 1050°C.

[0015] When aluminum is added to the mixture as an additional element, a lithium compound is added before the heat treatment at the first temperature, an aluminum compound is added after the second heat treatment, and a third heat treatment is performed.

[0016] The method for producing a positive electrode active material includes supplying an aqueous solution containing a water-soluble salt of nickel, a water-soluble salt of cobalt, and a water-soluble salt of manganese, and an alkaline solution to a reaction vessel, mixing the solutions inside the reaction vessel to precipitate a cobalt compound, heating a first mixture obtained by mixing the cobalt compound and the lithium compound at a first temperature, crushing or pulverizing the first mixture, and then heating the first mixture at a second temperature that is higher than the first temperature, and mixing the first mixture with an aluminum compound to obtain a second mixture, thereby producing the positive electrode active material.

[0017] In the coprecipitation method for precipitating the cobalt compound, an aqueous solution containing a water-soluble salt of nickel, a water-soluble salt of cobalt, and a water-soluble salt of manganese, and an alkaline solution are supplied to a reaction vessel and mixed inside the reaction vessel to precipitate a cobalt compound (a hydroxide containing cobalt, manganese, and nickel). This reaction may be referred to as a neutralization reaction, an acid-base reaction, or a coprecipitation reaction, and the compound containing at least nickel, cobalt, and manganese may be referred to as a precursor of at least a cobalt compound or lithium cobalt oxide, even if the cobalt content is at most. The cobalt compound (a hydroxide containing cobalt, manganese, and nickel) obtained by the coprecipitation reaction may be referred to as a precursor. The cobalt compound and lithium compound are then mixed to obtain a mixture.

[0018] The aqueous solution containing a water-soluble nickel salt can be an aqueous nickel sulfate solution or an aqueous nickel nitrate solution.

[0019] The aqueous solution containing a water-soluble salt of cobalt may be an aqueous cobalt sulfate solution or an aqueous cobalt nitrate solution.

[0020] As the aqueous solution in which a water-soluble salt of manganese is dissolved, an aqueous manganese sulfate solution or an aqueous manganese nitrate solution can be used.

[0021] When aluminum is added as an additional element to be contained in the mixture, an aluminum-containing aqueous solution is further supplied to the reaction vessel. When magnesium is added as an additional element to be contained in the mixture, a magnesium-containing aqueous solution is further supplied to the reaction vessel. When calcium is added as an additional element to be contained in the mixture, a calcium-containing aqueous solution is further supplied to the reaction vessel.

[0022] The pH inside the reaction vessel is preferably 9.0 or more and 11.0 or less, and more preferably 10.0 or more and 10.5 or less.

[0023] A chelating agent is added when the aqueous solution and the alkaline solution are mixed to precipitate the cobalt compound. Examples of chelating agents include glycine, oxine, 1-nitroso-2-naphthol, 2-mercaptobenzothiazole, and EDTA (ethylenediaminetetraacetic acid). Multiple agents selected from glycine, oxine, 1-nitroso-2-naphthol, and 2-mercaptobenzothiazole may also be used. The chelating agent is dissolved in pure water to form a chelating aqueous solution. The chelating agent is a complexing agent that forms a chelate compound and is preferable to general complexing agents. Of course, a complexing agent other than a chelating agent may also be used; for example, a general complexing agent such as an aqueous ammonia solution may be used.

[0024] The use of a chelate aqueous solution is preferred because it makes it easier to control the pH in the reaction vessel when obtaining the cobalt compound. The use of a chelate aqueous solution is also preferred because it suppresses the generation of unwanted crystal nuclei and promotes growth. Suppressing the generation of unwanted nuclei suppresses the generation of fine particles, thereby producing hydroxides with a good particle size distribution. The use of a chelate aqueous solution also slows the acid-base reaction, allowing the reaction to proceed gradually, resulting in the production of nearly spherical secondary particles. Glycine has the effect of maintaining a constant pH value at or near a pH of 9.0 to 10.0. Therefore, using a glycine aqueous solution as the chelate aqueous solution makes it easier to control the pH in the reaction vessel when obtaining the cobalt compound. Furthermore, the glycine concentration of the glycine aqueous solution in the aqueous solution containing the dissolved transition metal salt is preferably 0.05 mol / L to 0.09 mol / L.

[0025] The positive electrode active material obtained by the above method has crystals with a hexagonal layer structure. The crystals are not limited to single crystals (also called crystallites). In the case of polycrystals, several crystallites aggregate to form primary particles. A primary particle refers to a particle that is recognized as a single grain when observed under an SEM. A secondary particle refers to a mass of aggregated primary particles. The aggregation of primary particles does not depend on the bonding force acting between multiple primary particles. It may be a covalent bond, an ionic bond, a hydrophobic interaction, a van der Waals force, or other intermolecular interaction, or multiple bonding forces may be acting.

[0026] When coprecipitation is used, secondary particles may be formed.

[0027] The crystal having a hexagonal layer structure has one or more selected from the group consisting of a first transition metal, a second transition metal, and a third transition metal. Specifically, the first transition metal is nickel, the second transition metal is cobalt, the third transition metal is manganese, and LiNi ｘ Co ｙ Mn ｚ O ２A NiCoMn-based material (also referred to as NCM) represented by (x > 0, y > 0, z > 0, 0.8 < x + y + z < 1.2) can be used. Specifically, for example, it is preferable to satisfy 0.1x < y < 8x and 0.1x < z < 8x. As an example, it is preferable that x, y, and z satisfy x:y:z = 1:1:1 or a value thereabout. As another example, it is preferable that x, y, and z satisfy x:y:z = 5:2:3 or a value thereabout. As another example, it is preferable that x, y, and z satisfy x:y:z = 8:1:1 or a value thereabout. As another example, it is preferable that x, y, and z satisfy x:y:z = 9:0.5:0.5 or a value thereabout. As another example, it is preferable that x, y, and z satisfy x:y:z = 6:2:2 or a value thereabout. Alternatively, as an example, it is preferable that x, y, and z satisfy the relationship x:y:z=1:4:1 or values ​​close thereto.

[0028] Furthermore, the positive electrode active material obtained by the above method may contain, in addition to the first transition metal, the second transition metal, and the third transition metal, one or more elements selected from the group consisting of Al, Mg, Ca, Zr, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Nb, Mo, Sn, Ba, and La. It is preferable to contain Al, Mg, Ca, or Zr from the viewpoint of increasing the capacity retention rate after charge-discharge cycling of a secondary battery using the above positive electrode active material.

[0029] A secondary battery using the above-described positive electrode active material is also one of the configurations disclosed in this specification. The secondary battery has a positive electrode having a positive electrode active material and a negative electrode having a negative electrode active material. A separator is also provided between the positive electrode and the negative electrode. The separator is used to prevent short circuits, and a safe and highly reliable secondary battery can be provided.

[0030] When adding aluminum as an additive element to the positive electrode active material, the above-mentioned method is considered as the first method, but there are other methods. The second method is to add aluminum as an oxide before the first heat treatment. The third method is to use an aqueous solution containing aluminum as one of the aqueous solutions used in the coprecipitation method.

[0031] As described above, there are three methods for adding aluminum as an additive element to a positive electrode active material. Therefore, when adding aluminum as an additive element to a positive electrode active material, any one or a combination of the three methods described above can be used. For example, when adding a large amount of aluminum, aluminum can be incorporated into the positive electrode active material using an aluminum-containing aqueous solution in a coprecipitation process, followed by adding and mixing lithium and aluminum, heating at a first temperature to remove moisture, and then heating at a second temperature higher than the first temperature. After the second heating, aluminum can be added and the third heating can be performed.

[0032] According to one embodiment of the present invention, two heat treatments are performed to improve the mixing state of the mixture, thereby reducing voids in the secondary particles when a secondary battery is fabricated. Furthermore, three heat treatments, two before the addition of aluminum and one after the addition, can improve crystallinity. Therefore, a high-capacity positive electrode active material can be provided. Alternatively, a positive electrode active material that is relatively stable even after repeated charge and discharge can be provided. Alternatively, a secondary battery with high safety or reliability can be provided.

[0033] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims.

[0034] FIG. 1 illustrates an example of a production flow of a positive electrode active material according to one embodiment of the present invention. FIG. 2 illustrates an example of a production flow of a positive electrode active material according to one embodiment of the present invention. FIG. 3 illustrates a cross-sectional view of a reaction vessel used in one embodiment of the present invention. FIG. 4A is an exploded perspective view of a coin-type secondary battery, FIG. 4B is a perspective view of the coin-type secondary battery, and FIG. 4C is a cross-sectional perspective view thereof. FIG. 5A illustrates an example of a cylindrical secondary battery. FIG. 5B illustrates an example of a cylindrical secondary battery. FIG. 5C illustrates an example of a plurality of cylindrical secondary batteries. FIG. 5D illustrates an example of a power storage system including a plurality of cylindrical secondary batteries. FIGS. 6A and 6B illustrate an example of a secondary battery, and FIG. 6C illustrates the internal structure of the secondary battery. FIGS. 7A to 7C illustrate an example of a secondary battery. FIGS. 8A and 8B illustrate the external appearance of a secondary battery. FIGS. 9A to 9C illustrate a method for manufacturing a secondary battery. FIGS. 10A to 10C illustrate an example of a battery pack. FIGS. 11A and 11B illustrate an example of a secondary battery. FIGS. 12A to 12C are diagrams illustrating an example of a secondary battery. FIGS. 13A and 13B are diagrams illustrating an example of a secondary battery. FIG. 14A is a perspective view of a battery pack illustrating one embodiment of the present invention, FIG. 14B is a block diagram of the battery pack, and FIG. 14C is a block diagram of a vehicle having a motor. FIGS. 15A to 15D are diagrams illustrating an example of a transportation vehicle. FIGS. 16A and 16B are diagrams illustrating a power storage device according to one embodiment of the present invention. FIG. 17A is a diagram illustrating an electric bicycle, FIG. 17B is a diagram illustrating a secondary battery for the electric bicycle, and FIG. 17C is a diagram illustrating an electric motorcycle. FIGS. 18A to 18D are diagrams illustrating an example of an electronic device. FIG. 19 is a cross-sectional photograph of a positive electrode. FIG. 20 is a cross-sectional photograph of an enlarged portion of a positive electrode. FIGS. 21A and 21B are diagrams illustrating charge-discharge cycle characteristics of a secondary battery at 25° C. FIGS. 22A and 22B are diagrams illustrating charge-discharge cycle characteristics of a secondary battery at 45° C.

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various modifications can be made to the embodiments and details. Furthermore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0036] Embodiment 1 In this embodiment, an example of a method for producing a positive electrode active material 200A in which an additive element is added to a cobalt compound obtained by a coprecipitation method is described with reference to FIG. 1 . Note that the flow diagram shown in FIG. 1 shows the order of elements connected by lines. It does not show the time timing between elements that are not directly connected by lines. For example, although the production of mixed liquids 901 and 902 in FIG. 1 is shown at the same height in the figure, they do not necessarily have to be performed at the same time.

[0037] In this embodiment, a precursor (also called a coprecipitated precursor) having Co, Ni, or Mn present in one particle is prepared by a co-precipitation method, and a Li salt is mixed with the coprecipitated precursor, followed by heating twice and then adding aluminum.

[0038] As shown in FIG. 1 , a cobalt aqueous solution is prepared as aqueous solution 890, and an alkaline solution is prepared as aqueous solution 892. Aqueous solution 890 and aqueous solution 893 are mixed to prepare mixed solution 901. Aqueous solution 892 and aqueous solution 894 are mixed to prepare mixed solution 902. These mixed solutions 901 and 902 are reacted to produce a cobalt compound. This reaction may be referred to as a neutralization reaction, an acid-base reaction, or a coprecipitation reaction, and the cobalt compound may be referred to as a precursor of lithium cobalt oxide. The reaction that occurs by performing the process surrounded by the chain line in FIG. 1 may also be referred to as a coprecipitation reaction.

[0039] <Cobalt aqueous solution> As the cobalt aqueous solution, cobalt sulfate (for example, CoSO ４ ), cobalt chloride (e.g., CoCl ２ ) or cobalt nitrate (e.g., Co(NO ３ ) ２ ), cobalt acetate (e.g., C ４ H ６ CoO ４), cobalt alkoxide, or organic cobalt complex, or an aqueous solution containing a hydrate thereof. Alternatively, an organic acid of cobalt, such as cobalt acetate, or a hydrate thereof, may be used instead of the aqueous cobalt solution. In this specification, the organic acid includes citric acid, oxalic acid, formic acid, and butyric acid in addition to acetic acid.

[0040] For example, an aqueous solution of these compounds in pure water can be used. Because the cobalt aqueous solution is acidic, it can be referred to as an acid aqueous solution. The cobalt aqueous solution can also be referred to as a cobalt source in the manufacturing process of the positive electrode active material.

[0041] <Nickel aqueous solution> As the nickel aqueous solution, an aqueous solution of nickel sulfate, nickel chloride, nickel nitrate, or a hydrate thereof can be used. Also, an aqueous solution of an organic acid salt of nickel, such as nickel acetate, or a hydrate thereof can be used. Also, an aqueous solution of nickel alkoxide or an organic nickel complex can be used. The nickel aqueous solution can be referred to as the nickel source in the manufacturing process of the positive electrode active material.

[0042] <Manganese aqueous solution> As the manganese aqueous solution, a manganese salt such as manganese sulfate, manganese chloride, manganese nitrate, or an aqueous solution of a hydrate thereof can be used. Also, an aqueous solution of an organic acid salt of manganese, such as manganese acetate, or an aqueous solution of a hydrate thereof can be used. Furthermore, an aqueous solution of a manganese alkoxide or an organic manganese complex can be used.

[0043] The aqueous solution 890 may be prepared by preparing the above-mentioned cobalt aqueous solution, nickel aqueous solution, and manganese aqueous solution and then mixing them together, or, for example, nickel sulfate, cobalt sulfate, and manganese sulfate may be mixed together and then mixed with water to prepare the aqueous solution 890.

[0044] In this embodiment, nickel sulfate, cobalt sulfate, and manganese sulfate are weighed out in desired amounts and mixed together. Aqueous solution 890, which is a mixture of these, is mixed with aqueous solution 893 to prepare mixed solution 901, and mixed solution 902 is prepared from aqueous solutions 892 and 894, which are alkaline solutions. Aqueous solutions 893 and 894 are used as aqueous solutions that function as chelating agents, but are not particularly limited thereto and may be pure water. The manganese aqueous solution can be referred to as a manganese source in the manufacturing process of the positive electrode active material.

[0045] <Alkaline Solution> Examples of alkaline solutions include aqueous solutions containing sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia. For example, aqueous solutions in which these are dissolved in pure water can be used. Alternatively, the aqueous solution may be an aqueous solution in which multiple types selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide are dissolved in pure water.

[0046] <Reaction Conditions> When reacting aqueous solution 890 and aqueous solution 892 according to the coprecipitation method, the pH of the reaction system is adjusted to 9.0 or more and 11.0 or less, preferably 9.8 or more and 10.3 or less. For example, when aqueous solution 892 is placed in a reaction tank and aqueous solution 890 is dropped into the reaction tank, the pH of the aqueous solution in the reaction tank should be maintained within the above-mentioned range. The same applies when aqueous solution 890 is placed in a reaction tank and aqueous solution 892 is dropped into the reaction tank. The dropping rate of aqueous solution 890 or aqueous solution 892 should be 0.1 mL / min or more and 0.8 mL / min or less, which is preferable because it makes it easier to control the pH conditions. The reaction tank has a reaction vessel.

[0047] The aqueous solution in the reaction vessel is preferably stirred using a stirring means. The stirring means has a stirrer or stirring blades. Two to six stirring blades can be provided. For example, when four stirring blades are used, they are preferably arranged in a cross shape when viewed from above. The rotation speed of the stirring means is preferably 800 rpm to 1200 rpm.

[0048] The temperature of the reaction vessel is adjusted to be 50° C. or higher and 90° C. or lower. The dropping of the aqueous solution 892 or 890 may be started after the temperature has reached the appropriate temperature.

[0049] The inside of the reaction vessel is preferably an inert atmosphere. For example, when a nitrogen atmosphere is used, nitrogen gas is preferably introduced at a flow rate of 0.5 L / min to 2 L / min.

[0050] The reactor may also be equipped with a reflux condenser, which allows nitrogen gas to escape from the reactor and water to return to the reactor.

[0051] After the above reaction, a cobalt compound precipitates in the reaction tank. Filtration is performed to recover the cobalt compound. During filtration, it is preferable to wash the reaction product precipitated in the reaction tank with pure water, and then add an organic solvent with a low boiling point (e.g., acetone) before performing the above filtration.

[0052] The filtered cobalt compound may be further dried, for example, at 60° C. to 90° C. in vacuum for 0.5 to 3 hours. In this way, the cobalt compound can be obtained.

[0053] The cobalt compound obtained by the above reaction is cobalt hydroxide (e.g., Co(OH) ２ ). After filtration, cobalt hydroxide is obtained as secondary particles formed by aggregation of primary particles. In this specification, primary particles refer to the smallest unit particles (lumps) that do not have grain boundaries when observed with a scanning electron microscope (SEM) at, for example, 5000x magnification. In other words, primary particles refer to the smallest unit particles surrounded by grain boundaries. Secondary particles refer to particles that are not easily separated (particles independent from others) because the primary particles aggregate so as to share part of the grain boundaries (the outer peripheries of the primary particles). In other words, secondary particles may have grain boundaries.

[0054] Next, a lithium compound is prepared.

[0055] <Lithium Compound> As the lithium compound, Li salts such as lithium hydroxide (e.g., LiOH), lithium carbonate (e.g., Li ２ CO ３ ), or lithium nitrate (e.g., LiNO ３) are examples. In particular, it is preferable to use a material with a low melting point among lithium compounds, such as lithium hydroxide (melting point 462°C). Positive electrode active materials with a high proportion of nickel are more susceptible to cation mixing than lithium cobalt oxide, so the first heating must be performed at a low temperature. Therefore, it is preferable to use a material with a low melting point.

[0056] In this embodiment, the cobalt compound and the lithium compound are weighed out in desired amounts and mixed together to obtain the mixture 904. The mixing is carried out using a mortar or a stirring mixer.

[0057] Next, the first heating is performed. As a firing device for performing the first heating, an electric furnace or a rotary kiln can be used.

[0058] Next, the secondary particles are crushed or pulverized in a mortar to break up any clumps of particles, and then recovered. Furthermore, classification may be performed using a sieve. In this embodiment, a crucible made of aluminum oxide (also called alumina) with a purity of 99.9% is used. Furthermore, when recovering the material after heating, it is preferable to transfer the material from the crucible to a mortar and then recover it, since this prevents impurities from being mixed into the material. Furthermore, it is preferable that the mortar be made of a material that does not easily release impurities. Specifically, it is preferable to use a mortar made of alumina with a purity of 90% or more, preferably 99% or more.

[0059] Next, the second heating is performed. As a firing apparatus for performing the second heating, an electric furnace or a rotary kiln can be used.

[0060] The second temperature is at least higher than the first temperature, and is preferably higher than 700°C and lower than 1050°C. The second heating time is preferably 1 hour or longer and 20 hours or shorter. The second heating is preferably performed in an oxygen atmosphere, and it is particularly preferable to perform the second heating while supplying oxygen. For example, the flow rate is 10 L / min per 1 L of the furnace volume. Specifically, the mixture 904 is preferably heated with the container containing the mixture 904 covered.

[0061] The secondary particles are then crushed or pulverized in a mortar to break up any clumps of particles, and then recovered. The particles may then be classified using a sieve.

[0062] Then, the obtained mixture 905 and compound 910 are mixed.

[0063] <Compound 910> As the source of the additive element, one or more selected from aluminum salts, magnesium salts, and calcium salts are used. The compound 910 may be aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, basic magnesium carbonate (MgCO ３ ) ３ Mg(OH) ２ ・3H ２ In this embodiment, an aluminum salt is used as the additive element source, and aluminum hydroxide (Al(OH) ３ ) is used. The amount of compound 910 used as the additive element source is suitably weighed by the practitioner so that the desired amount is contained, and it is desirable to add aluminum, magnesium, or calcium in the range of 0.5 atm % to 3 atm % relative to the cobalt compound. Note that the concentration of the additive element here is a value based on the amount added during production of the secondary particles, and may not match the actual analytical concentration.

[0064] Thereafter, a third heating step is performed. The third temperature is at least higher than the first temperature, and is preferably higher than 700°C and lower than 1050°C. The time period for the third heating step is shorter than that for the second heating step, and is preferably between 1 hour and 20 hours. The third heating step is preferably performed in an oxygen atmosphere, and it is particularly preferable to perform the third heating step while supplying oxygen. For example, the flow rate is 10 L / min per 1 L of the furnace volume. Specifically, the heating step is preferably performed with the container containing the mixture 905 covered.

[0065] Next, the secondary particles are crushed or pulverized in a mortar to loosen the particles, and then collected. The particles may be further classified using a sieve. The crushing step can further uniformize the particle size and / or shape of the positive electrode active material 200A.

[0066] The above steps can produce the positive electrode active material 200A. The positive electrode active material 200A obtained by the above steps is an NCM to which Al has been added, and is therefore sometimes called NCMA.

[0067] (Embodiment 2) One embodiment of the present invention is not limited to the process flow of FIG. 1 . In this embodiment, nickel sulfate, cobalt sulfate, and manganese sulfate are weighed out in desired amounts and mixed together. These are mixed with an aqueous solution 893 to prepare a mixed solution 901, a mixed solution 902 of an aqueous solution 892 and an aqueous solution 894, which are alkaline solutions, and a mixed solution 906 of an aqueous solution 896 containing an additive element and an aqueous solution 895. The aqueous solutions 893, 894, and 895 are aqueous solutions that function as a chelating agent, but are not particularly limited thereto and may be pure water.

[0068] 2, an aqueous solution 896 containing an additional element is used as a material for producing a cobalt compound by coprecipitation. When aluminum is added as an additional element, an aqueous solution of aluminum is also supplied to the reaction tank. When magnesium is added as an additional element to be contained in the mixture, an aqueous solution of magnesium is also supplied to the reaction tank. When calcium is added as an additional element to be contained in the mixture, an aqueous solution of calcium is also supplied to the reaction tank.

[0069] The pH inside the reaction vessel is preferably 9.0 or more and 11.0 or less, and more preferably 10.0 or more and 10.5 or less.

[0070] Next, a compound 910 is prepared as an oxide containing a lithium compound and an additive element.

[0071] As shown in FIG. 2, the cobalt compound obtained by the coprecipitation method is mixed with the lithium compound to obtain a mixture 908 .

[0072] After the mixture 908 is obtained, the mixture is subjected to the first heating. As a firing apparatus for the first heating, an electric furnace or a rotary kiln can be used.

[0073] Next, the second heating is performed. As a firing apparatus for performing the second heating, an electric furnace or a rotary kiln can be used.

[0074] The second temperature is at least higher than the first temperature, and is preferably higher than 700°C and lower than 1050°C. The second heating time is preferably 1 hour or longer and 20 hours or shorter. The second heating is preferably performed in an oxygen atmosphere, and it is particularly preferable to perform the second heating while supplying oxygen. For example, the flow rate is 10 L / min per 1 L of the furnace volume. Specifically, the mixture 908 is preferably heated with the container containing the mixture 908 covered.

[0075] The secondary particles are then crushed or pulverized in a mortar to break up any clumps of particles, and then recovered. The particles may then be classified using a sieve.

[0076] Then, the obtained mixture 909 and compound 910 are mixed.

[0077] Thereafter, a third heating is performed. The third temperature is at least higher than the first temperature, and is preferably higher than 700°C and equal to or lower than 1050°C. The third heating time is preferably 1 hour or more and 20 hours or less. The third heating is preferably performed in an oxygen atmosphere, and it is particularly preferable to perform the third heating while supplying oxygen. For example, the flow rate is 10 L / min per 1 L of the furnace volume. Specifically, the heating is preferably performed with the container containing the mixture 909 covered.

[0078] Next, the secondary particles are crushed or pulverized in a mortar to loosen the particles, and then collected. The particles may be further classified using a sieve. The crushing step can further uniformize the particle size and / or shape of the positive electrode active material 200B.

[0079] The above steps can produce positive electrode active material 200B. Note that, since the process is partially different from that of positive electrode active material 200A obtained in Fig. 1, the composition finally obtained in the production flow of Fig. 2 may not be the same as that in the production flow of Fig. 1.

[0080] 2 shows an example in which the additive element is mixed three times, but this is not particularly limited, and a process in which one or more additive elements are mixed may be used. Also, different types of additive elements may be combined. Using the production flow of FIG. 2, three different types of additive elements can be added to the positive electrode active material 200B.

[0081] This embodiment mode can be freely combined with other embodiment modes.

[0082] Embodiment Mode 3 In this embodiment mode, a coprecipitation apparatus for performing the coprecipitation method in the manufacturing methods of Embodiment Modes 1 to 3 will be described below.

[0083] The coprecipitation synthesis apparatus 170 shown in FIG. 3 includes a reaction tank 171, which includes a reaction vessel. A separable flask is preferably used at the bottom of the reaction vessel and a separable cover is preferably used at the top. The separable flask may be cylindrical or round. In the case of a cylindrical flask, the separable flask has a flat bottom. The atmosphere within the reaction tank 171 can be controlled using at least one inlet of the separable cover. For example, the atmosphere preferably contains nitrogen. In this case, it is preferable to flow nitrogen into the reaction tank 171. It is also preferable to bubble nitrogen through the aqueous solution 192 within the reaction tank 171. The coprecipitation synthesis apparatus 170 may include a reflux condenser connected to at least one inlet of the separable cover. This reflux condenser can exhaust atmospheric gases, such as nitrogen, within the reaction tank 171 and return water to the reaction tank 171. The atmosphere within the reaction tank 171 only needs to have an airflow of a sufficient volume to exhaust gases generated by the thermal decomposition reaction resulting from the heat treatment.

[0084] 1 and 3, the procedure of the coprecipitation method enclosed by the chain line in FIG. 1 will be described.

[0085] First, an aqueous solution 894 (chelating agent) is placed in the reaction tank 171, and then the mixed solution 901 and the aqueous solution 892 (alkaline solution) are added dropwise to the reaction tank 171. The aqueous solution 192 in Fig. 3 shows the state when the addition has started. The aqueous solution 894 may be referred to as a "filling liquid." The "filling liquid" may also be referred to as an "adjusting liquid," and may refer to the aqueous solution before the reaction, i.e., the aqueous solution in its initial state.

[0086] Other components of the coprecipitation synthesis apparatus 170 shown in Fig. 3 will be described. The coprecipitation synthesis apparatus 170 includes a stirring unit 172, a stirring motor 173, a thermometer 174, a tank 175, a pipe 176, a pump 177, a tank 180, a pipe 181, a pump 182, a tank 186, a pipe 187, a pump 188, and a control device 190.

[0087] The stirring unit 172 can stir the aqueous solution 192 in the reaction tank 171, and further has a stirring motor 173 as a power source for rotating the stirring unit 172. The stirring unit 172 has paddle-type stirring blades (referred to as paddle blades), and the paddle blades may have two to six blades, and the blades may have an inclination of 40 degrees to 70 degrees.

[0088] The thermometer 174 can measure the temperature of the aqueous solution 192. The temperature of the reaction tank 171 can be controlled using a thermoelectric element so that the temperature of the aqueous solution 192 is constant. An example of a thermoelectric element is a Peltier element. Although not shown, a pH meter is also placed in the reaction tank 171, and can measure the pH of the aqueous solution 192.

[0089] Each tank can store a different aqueous raw material solution. For example, each tank can be filled with a mixed solution 901 and an aqueous solution 892. A tank filled with an aqueous solution 894 that functions as a filler liquid may also be prepared. Each tank is provided with a pump, and by using this pump, the aqueous raw material solution can be dripped into the reaction tank 171 through the pipe. Each pump can control the amount of aqueous raw material solution dripped, i.e., the amount of solution sent. In addition to the pump, a valve may be provided in the pipe 176 to control the amount of aqueous raw material solution dripped, i.e., the amount of solution sent.

[0090] The control device 190 is electrically connected to the stirring motor 173, the thermometer 174, the pump 177, the pump 182, and the pump 188, and can control the rotation speed of the stirring unit 172, the temperature of the aqueous solution 192, and the amount of each raw aqueous solution dropped.

[0091] The rotation speed of the stirring unit 172, specifically the rotation speed of the paddle blades, is preferably, for example, 800 rpm or more and 1200 rpm or less. The stirring is preferably performed while heating the aqueous solution 192 to 50°C or more and 90°C or less. During this process, the mixed solution 901 is preferably dripped into the reaction tank 171 at a constant rate. Of course, the rotation speed of the paddle blades is not limited to a constant value and can be adjusted as appropriate. For example, the rotation speed can be changed depending on the amount of liquid in the reaction tank 171. The dripping speed of the mixed solution 901 can also be adjusted. The dripping speed can be adjusted to maintain a constant pH in the reaction tank 171. Alternatively, the dripping speed can be controlled so that the mixed solution 901 is dripped first, and then the aqueous solution 892 is dripped when the pH value fluctuates from the desired value. The pH value is preferably set to 9.0 or more and 11.0 or less, preferably 9.8 or more and 10.3 or less.

[0092] After the above steps, a reaction product is precipitated in the reaction tank 171. The reaction product contains a cobalt compound. This reaction can be referred to as coprecipitation, and this step may be referred to as a coprecipitation step.

[0093] This embodiment mode can be freely combined with other embodiment modes.

[0094] (Embodiment 4) An example of a coin-type secondary battery will be described. Fig. 4A is an exploded perspective view of a coin-type (single-layer flat) secondary battery, Fig. 4B is an external view, and Fig. 4C is a cross-sectional view thereof. Coin-type secondary batteries are mainly used in small electronic devices. In this specification, coin-type batteries include button-type batteries.

[0095] 4A is a schematic diagram that shows the overlapping of components (upper and lower relationships and positional relationships) for ease of understanding, and therefore, FIGS. 4A and 4B are not completely identical corresponding views.

[0096] In Fig. 4A, a positive electrode 304, a separator 310, a negative electrode 307, a spacer 322, and a washer 312 are stacked. These are sealed by a negative electrode can 302 and a positive electrode can 301. Note that a gasket for sealing is not shown in Fig. 4A. The spacer 322 and the washer 312 are used to protect the inside or to fix the position inside the can when the positive electrode can 301 and the negative electrode can 302 are crimped together. The spacer 322 and the washer 312 are made of stainless steel or an insulating material.

[0097] A positive electrode 304 has a laminated structure in which a positive electrode active material layer 306 is formed on a positive electrode current collector 305 .

[0098] To prevent short-circuiting between the positive electrode and the negative electrode, a separator 310 and a ring-shaped insulator 313 are arranged so as to cover the side and top surfaces of the positive electrode 304. The separator 310 has a larger planar area than the positive electrode 304.

[0099] FIG. 4B is a perspective view of the completed coin-type secondary battery.

[0100] In the coin-type secondary battery 300, a positive electrode can 301, which also serves as a positive electrode terminal, and a negative electrode can 302, which also serves as a negative electrode terminal, are insulated and sealed by a gasket 303 made of polypropylene. The positive electrode 304 is formed by a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact with the positive electrode current collector. The negative electrode 307 is formed by a negative electrode current collector 308 and a negative electrode active material layer 309 provided in contact with the negative electrode current collector. The negative electrode 307 is not limited to a laminated structure, and may be made of lithium metal foil or a lithium-aluminum alloy foil.

[0101] It is to be noted that the positive electrode 304 and the negative electrode 307 used in the coin-type secondary battery 300 each only need to have an active material layer formed on one side.

[0102] The positive electrode can 301 and the negative electrode can 302 can be made of nickel, aluminum, titanium, or alloys thereof, or alloys of these with other metals (e.g., stainless steel), which are corrosion-resistant to liquid electrolytes. Furthermore, nickel and aluminum coatings are preferably used to prevent corrosion by the liquid electrolyte. The positive electrode can 301 is electrically connected to the positive electrode 304, and the negative electrode can 302 is electrically connected to the negative electrode 307.

[0103] These negative electrode 307, positive electrode 304, and separator 310 are immersed in a liquid electrolyte, and as shown in FIG. 4C , the positive electrode 304, separator 310, negative electrode 307, and negative electrode can 302 are stacked in this order with the positive electrode can 301 facing downwards, and the positive electrode can 301 and the negative electrode can 302 are crimped together via a gasket 303, thereby producing a coin-shaped secondary battery 300.

[0104] The above-described configuration allows the coin-type secondary battery 300 to have a high capacity, a high charge / discharge capacity, and excellent cycle characteristics. Note that, when a secondary battery having a solid electrolyte layer between the negative electrode 307 and the positive electrode 304 is used, the separator 310 may be unnecessary.

[0105] [Cylindrical Secondary Battery] An example of a cylindrical secondary battery will be described with reference to Fig. 5A. As shown in Fig. 5A, a cylindrical secondary battery 616 has a positive electrode cap (battery lid) 601 on the top surface and a battery can (external can) 602 on the side and bottom surfaces. The positive electrode cap 601 and the battery can (external can) 602 are insulated by a gasket (insulating packing) 610.

[0106] 5B is a schematic diagram showing a cross section of a cylindrical secondary battery. The cylindrical secondary battery shown in FIG. 5B has a positive electrode cap (battery lid) 601 on the top surface and a battery can (external can) 602 on the side and bottom surfaces. The positive electrode cap and battery can (external can) 602 are insulated by a gasket (insulating packing) 610.

[0107] A battery element is provided inside a hollow cylindrical battery can 602, which includes a strip-shaped positive electrode 604 and a negative electrode 606 wound with a separator 605 sandwiched between them. Although not shown, the battery element is wound around a central axis. One end of the battery can 602 is closed and the other end is open. The battery can 602 can be made of metals resistant to corrosion in liquid electrolytes, such as nickel, aluminum, and titanium, or alloys of these metals and other metals (e.g., stainless steel). To prevent corrosion by the liquid electrolyte, the battery can 602 is preferably coated with nickel and aluminum. Inside the battery can 602, the wound battery element, which includes the positive electrode, negative electrode, and separator, is sandwiched between a pair of opposing insulating plates 608 and 609. A nonaqueous electrolyte (not shown) is poured into the battery can 602, which contains the battery element. The nonaqueous electrolyte may be the same as that used in coin-type secondary batteries.

[0108] Since the positive and negative electrodes used in a cylindrical storage battery are wound, it is preferable to form active materials on both sides of the current collector. While Figures 5A to 5D illustrate a secondary battery 616 in which the height of the cylinder is greater than the diameter, this is not limiting. A secondary battery in which the diameter of the cylinder is greater than the height of the cylinder may also be used. This configuration, for example, can reduce the size of the secondary battery.

[0109] By using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for the positive electrode 604, a cylindrical secondary battery 616 with high capacity, high charge / discharge capacity, and excellent cycle characteristics can be obtained.

[0110] A positive electrode terminal (positive electrode current collector lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collector lead) 607 is connected to the negative electrode 606. Both the positive electrode terminal 603 and the negative electrode terminal 607 can be made of aluminum. The positive electrode terminal 603 is resistance-welded to a safety valve mechanism 613, and the negative electrode terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 613 is electrically connected to the positive electrode cap 601 via a PTC (Positive Temperature Coefficient) element 611. The safety valve mechanism 613 cuts off the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the increase in internal pressure of the battery exceeds a predetermined threshold. The PTC element 611 is a thermosensitive resistor whose resistance increases as the temperature increases, and the increased resistance limits the amount of current to prevent abnormal heat generation. The PTC element is made of barium titanate (BaTiO ３ )-based semiconductor ceramics can be used.

[0111] 5C shows an example of a power storage system 615. The power storage system 615 has a plurality of secondary batteries 616. The positive electrodes of each secondary battery are in contact with and electrically connected to conductors 624 separated by insulators 625. The conductors 624 are electrically connected to a control circuit 620 via wiring 623. The negative electrodes of each secondary battery are electrically connected to the control circuit 620 via wiring 626. A protection circuit that prevents overcharging or overdischarging can be used as the control circuit 620.

[0112] 5D shows an example of a power storage system 615. The power storage system 615 has a plurality of secondary batteries 616, which are sandwiched between a conductive plate 628 and a conductive plate 614. The plurality of secondary batteries 616 are electrically connected to the conductive plate 628 and the conductive plate 614 by wiring 627. The plurality of secondary batteries 616 may be connected in parallel, in series, or in parallel and then further connected in series. By configuring the power storage system 615 to have a plurality of secondary batteries 616, it is possible to extract a large amount of power.

[0113] A plurality of secondary batteries 616 may be connected in parallel and then further connected in series.

[0114] A temperature control device may be provided between the multiple secondary batteries 616. When the secondary batteries 616 are overheated, they can be cooled by the temperature control device, and when the secondary batteries 616 are too cold, they can be heated by the temperature control device. This makes it difficult for the performance of the power storage system 615 to be affected by the outside air temperature.

[0115] 5D , the power storage system 615 is electrically connected to a control circuit 620 via wiring 621 and wiring 622. The wiring 621 is electrically connected to the positive electrodes of the plurality of secondary batteries 616 via a conductive plate 628, and the wiring 622 is electrically connected to the negative electrodes of the plurality of secondary batteries 616 via a conductive plate 614.

[0116] [Another Example of Secondary Battery Structure] An example of the structure of a secondary battery will be described with reference to FIGS. 6 and 7. FIG.

[0117] The secondary battery 913 shown in FIG. 6A has a wound body 950 provided with terminals 951 and 952 inside a housing 930. The wound body 950 is immersed in a liquid electrolyte inside the housing 930. The terminal 952 contacts the housing 930, and the terminal 951 is not in contact with the housing 930 due to the use of an insulating material. Note that in FIG. 6A , the housing 930 is shown separated for convenience, but in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930. The housing 930 can be made of a metal material (e.g., aluminum) or a resin material.

[0118] 6B, the housing 930 shown in Fig. 6A may be formed of a plurality of materials. For example, the secondary battery 913 shown in Fig. 6B has a housing 930a and a housing 930b bonded together, and a wound body 950 is provided in the area surrounded by the housing 930a and the housing 930b.

[0119] The housing 930a can be made of an insulating material such as organic resin. In particular, by using organic resin on the surface on which the antenna is formed, it is possible to prevent the secondary battery 913 from blocking the electric field. Note that if the electric field blocking effect of the housing 930a is small, the antenna may be provided inside the housing 930a. The housing 930b can be made of, for example, a metal material.

[0120] 6C shows the structure of the wound body 950. The wound body 950 has a negative electrode 931, a positive electrode 932, and a separator 933. The wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are stacked on top of each other with the separator 933 sandwiched therebetween, and the laminated sheet is wound. Note that multiple layers of the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked.

[0121] 7A to 7C may be used as a secondary battery 913 having a wound body 950a. The wound body 950a shown in Fig. 7A includes a negative electrode 931, a positive electrode 932, and a separator 933. The negative electrode 931 includes a negative electrode active material layer 931a. The positive electrode 932 includes a positive electrode active material layer 932a.

[0122] By using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for the positive electrode 932, the secondary battery 913 can have a high capacity, a high charge / discharge capacity, and excellent cycle characteristics.

[0123] The separator 933 has a width wider than the negative electrode active material layer 931 a and the positive electrode active material layer 932 a, and is wound so as to overlap the negative electrode active material layer 931 a and the positive electrode active material layer 932 a. From the standpoint of safety, it is preferable that the negative electrode active material layer 931 a be wider than the positive electrode active material layer 932 a. A wound body 950 a having such a shape is preferable due to its high safety and productivity.

[0124] 7B, the negative electrode 931 is electrically connected to a terminal 951. The terminal 951 is electrically connected to a terminal 911a. The positive electrode 932 is electrically connected to a terminal 952. The terminal 952 is electrically connected to a terminal 911b.

[0125] 7C , the wound body 950a and the liquid electrolyte are covered by the housing 930 to form the secondary battery 913. It is preferable to provide a safety valve and an overcurrent protection element in the housing 930. The safety valve is a valve that opens when the inside of the housing 930 reaches a predetermined internal pressure to prevent the battery from exploding.

[0126] As shown in Fig. 7B, the secondary battery 913 may have multiple wound bodies 950a. Using multiple wound bodies 950a can result in a secondary battery 913 with a larger charge / discharge capacity. For other elements of the secondary battery 913 shown in Figs. 7A and 7B, the descriptions of the secondary battery 913 shown in Figs. 6A to 6C can be referred to.

[0127] 8A and 8B show examples of external views of a laminated secondary battery, which includes a positive electrode 503, a negative electrode 506, a separator 507, an outer casing 509, a positive electrode lead electrode 510, and a negative electrode lead electrode 511.

[0128] 9A shows an external view of a positive electrode 503 and a negative electrode 506. The positive electrode 503 has a positive electrode current collector 501, and a positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The positive electrode 503 also has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as a tab region). The negative electrode 506 has a negative electrode current collector 504, and a negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. The negative electrode 506 also has a region where the negative electrode current collector 504 is partially exposed, i.e., a tab region. The area and shape of the tab regions of the positive electrode and negative electrode are not limited to the example shown in FIG. 9A .

[0129] <Method of Manufacturing Laminated Secondary Battery> Here, an example of a method of manufacturing the laminated secondary battery whose external view is shown in FIG. 8A will be described with reference to FIGS. 9B and 9C.

[0130] First, the negative electrode 506, separator 507, and positive electrode 503 are stacked. FIG. 9B shows the stacked negative electrode 506, separator 507, and positive electrode 503. Here, an example is shown in which five pairs of negative electrodes and four pairs of positive electrodes are used. This can also be called a laminate consisting of a negative electrode, a separator, and a positive electrode. Next, the tab regions of the positive electrode 503 are joined together, and the positive electrode lead electrode 510 is joined to the tab region of the outermost positive electrode. For example, ultrasonic welding may be used for joining. Similarly, the tab regions of the negative electrode 506 are joined together, and the negative electrode lead electrode 511 is joined to the tab region of the outermost negative electrode.

[0131] Next, the negative electrode 506 , the separator 507 and the positive electrode 503 are arranged on the outer casing 509 .

[0132] Next, as shown in Figure 9C, the exterior body 509 is folded at the portion indicated by the dashed line. Thereafter, the outer periphery of the exterior body 509 is joined. For example, thermocompression bonding may be used for joining. At this time, an area (hereinafter referred to as an inlet) that is not joined is provided in a part (or one side) of the exterior body 509 so that a liquid electrolyte can be introduced later.

[0133] Next, a liquid electrolyte (not shown) is introduced into the inside of the exterior body 509 through an inlet provided in the exterior body 509. The introduction of the liquid electrolyte is preferably carried out under a reduced pressure atmosphere or an inert atmosphere. Finally, the inlet is joined. In this manner, the laminated secondary battery 500 can be fabricated.

[0134] By using the positive electrode active material 200A described in embodiment 1 or the positive electrode active material 200B described in embodiment 2 for the positive electrode 503, the secondary battery 500 can have a high capacity, a high charge / discharge capacity, and excellent cycle characteristics.

[0135] [Example of Battery Pack] An example of a secondary battery pack according to one embodiment of the present invention that can be wirelessly charged using an antenna will be described with reference to FIGS. 10A to 10C. FIG.

[0136] Fig. 10A is a diagram showing the appearance of secondary battery pack 531, which has a thin rectangular parallelepiped shape (also called a thick flat plate shape). Fig. 10B is a diagram illustrating the configuration of secondary battery pack 531. Secondary battery pack 531 has circuit board 540 and secondary battery 513. Label 529 is affixed to secondary battery 513. Circuit board 540 is fixed with sticker 515. Secondary battery pack 531 also has antenna 517.

[0137] The interior of the secondary battery 513 may have a structure including a wound body or a laminated body.

[0138] 10B , the secondary battery pack 531 has a control circuit 590 on a circuit board 540. The circuit board 540 is electrically connected to the terminals 514. The circuit board 540 is also electrically connected to the antenna 517, one 551 of the positive electrode lead and the negative electrode lead of the secondary battery 513, and the other 552 of the positive electrode lead and the negative electrode lead of the secondary battery 513.

[0139] Alternatively, as shown in FIG. 10C, the device may have a circuit system 590 a provided on the circuit board 540 and a circuit system 590 b electrically connected to the circuit board 540 via the terminals 514 .

[0140] The antenna 517 is not limited to a coil shape, and may be, for example, a wire shape or a plate shape. Furthermore, antennas such as a planar antenna, an aperture antenna, a traveling wave antenna, an EH antenna, a magnetic field antenna, and a dielectric antenna may also be used. Alternatively, the antenna 517 may be a flat conductor. This flat conductor can function as one of the conductors for electric field coupling. In other words, the antenna 517 may function as one of the two conductors of a capacitor. This allows power to be exchanged not only by electromagnetic fields and magnetic fields, but also by electric fields.

[0141] The secondary battery pack 531 includes a layer 519 between the antenna 517 and the secondary battery 513. The layer 519 has a function of, for example, shielding an electromagnetic field generated by the secondary battery 513. The layer 519 can be formed using, for example, a magnetic material.

[0142] The content of this embodiment can be freely combined with the content of other embodiment modes.

[0143] Embodiment 5 In this embodiment, an example of manufacturing an all-solid-state battery using the positive electrode active material 200A shown in Embodiment 1 or the positive electrode active material 200B shown in Embodiment 2 will be described.

[0144] As shown in FIG. 11A , a secondary battery 400 of one embodiment of the present invention includes a positive electrode 410 , a solid electrolyte layer 420 , and a negative electrode 430 .

[0145] Positive electrode 410 includes positive electrode current collector 413 and positive electrode active material layer 414. Positive electrode active material layer 414 includes positive electrode active material 411 and solid electrolyte 421. Positive electrode active material 200A described in Embodiment 1 or positive electrode active material 200B described in Embodiment 2 is used as positive electrode active material 411. Positive electrode active material layer 414 may include a conductive additive and a binder.

[0146] Solid electrolyte layer 420 has solid electrolyte 421. Solid electrolyte layer 420 is located between positive electrode 410 and negative electrode 430, and is a region that has neither positive electrode active material 411 nor negative electrode active material 431.

[0147] The negative electrode 430 includes a negative electrode current collector 433 and a negative electrode active material layer 434. The negative electrode active material layer 434 includes a negative electrode active material 431 and a solid electrolyte 421. The negative electrode active material layer 434 may also include a conductive additive and a binder. When metallic lithium is used as the negative electrode active material 431, it is not necessary to form the material into particles. Therefore, as shown in FIG. 11B , the negative electrode 430 can be formed without the solid electrolyte 421. FIG. 11B also illustrates an example in which the negative electrode active material 431 is formed as a film using a sputtering method. Using metallic lithium for the negative electrode 430 is preferable because it can improve the energy density of the secondary battery 400.

[0148] The solid electrolyte 421 of the solid electrolyte layer 420 may be, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte.

[0149] The sulfide-based solid electrolytes include thiolithium-based (Li １０ GeP ２ S １２ , Li ３．２５ Ge ０．２５ P ０．７５ S ４ ), sulfide glass (70Li ２ S・30P ２ S ５ , 30Li ２ S・26B ２ S ３ ・44LiI, 63Li ２ S・36SiS ２ ・1Li ３ P.O. ４, 57Li ２ S・38SiS ２ ・5Li ４ SiO ４ , 50Li ２ S・50GeS ２ ), sulfide crystallized glass (Li ７ P ３ S １１ , Li ３．２５ P ０．９５ S ４ Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, making it easy to maintain conductive paths even after charging and discharging.

[0150] The oxide-based solid electrolyte includes a material having a perovskite crystal structure (La ２／３−ｘ Li ３ｘ TiO ３ ), a material having a NASICON type crystal structure (Li １−Ｙ Al Ｙ Ti ２−Ｙ (P.O. ４ ) ３ ), materials having a garnet-type crystal structure (Li ７ La ３ Zr ２ O １２ ), a material having a LISICON type crystal structure (Li １４ ZnGe ４ O １６ ), LLZO(Li ７ La ３ Zr ２ O １２ ), oxide glass (Li ３ P.O. ４ -Li ４ SiO ４ , 50Li ４ SiO ４ ・50Li ３ BO ３ ), oxide crystallized glass (Li １．０７ Al ０．６９ Ti １．４６ (P.O. ４ ) ３ , Li １．５ Al ０．５ Ge １．５ (P.O. ４ ) ３Oxide-based solid electrolytes have the advantage of being stable in the atmosphere.

[0151] Halide-based solid electrolytes include LiAlCl ４ , Li ３ InBr ６ , LiF, LiCl, LiBr, and LiI. Furthermore, composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can also be used as solid electrolytes.

[0152] Also, different solid electrolytes may be mixed and used.

[0153] Among them, Li having a NASICON type crystal structure １＋ｘ Al ｘ Ti ２−ｘ (P.O. ４ ) ３ Since (0[x[1) (hereinafter referred to as LATP) contains aluminum and titanium, which are elements that may be contained in the positive electrode active material used in the secondary battery 400 of one embodiment of the present invention, a synergistic effect can be expected in improving cycle characteristics, which is preferable. In addition, productivity can be improved by reducing the number of steps. Note that in this specification, the NASICON-type crystal structure refers to a structure in which M ２ (XO ４ ) ３ (M: transition metal, X: S, P, As, Mo, or W), ６ Octahedron and XO ４ It refers to a structure in which tetrahedrons are arranged three-dimensionally with their vertices shared.

[0154] [Exterior Body and Shape of Secondary Battery] Various materials and shapes can be used for the exterior body of the secondary battery 400 of one embodiment of the present invention, but it is preferable that the exterior body has a function of applying pressure to the positive electrode, the solid electrolyte layer, and the negative electrode.

[0155] For example, FIG. 12 shows an example of a cell for evaluating materials for an all-solid-state battery.

[0156] 12A is a schematic cross-sectional view of the evaluation cell, which has a lower member 761, an upper member 762, and a fixing screw or wing nut 764 that fixes them together, and electrode plate 753 is pressed to fix the evaluation material by rotating a holding screw 763. An insulator 766 is provided between lower member 761 and upper member 762, both made of stainless steel. An O-ring 765 is also provided between upper member 762 and holding screw 763 to provide a tight seal.

[0157] The evaluation material is placed on electrode plate 751, surrounded by insulating tube 752, and pressed from above by electrode plate 753. An enlarged perspective view of the evaluation material and its surroundings is shown in Figure 12B.

[0158] The evaluation material is an example of a laminate of a positive electrode 750a, a solid electrolyte layer 750b, and a negative electrode 750c, and its cross-sectional view is shown in Fig. 12C. Note that the same reference numerals are used for the same parts in Figs. 12A to 12C.

[0159] The electrode plate 751 and the lower member 761, which are electrically connected to the positive electrode 750a, can be said to correspond to a positive electrode terminal. The electrode plate 753 and the upper member 762, which are electrically connected to the negative electrode 750c, can be said to correspond to a negative electrode terminal. The electrical resistance can be measured by applying pressure to the evaluation material via the electrode plate 751 and the electrode plate 753.

[0160] The secondary battery of one embodiment of the present invention preferably uses an airtight package for its exterior. For example, a ceramic package or a resin package can be used. Furthermore, the exterior is preferably sealed in a sealed atmosphere, such as in a glove box, while blocking external air.

[0161] Fig. 13A is a perspective view of a secondary battery of one embodiment of the present invention, which has an exterior body and a shape different from those in Fig. 12. The secondary battery in Fig. 13A has external electrodes 771 and 772 and is sealed in an exterior body having a plurality of package members.

[0162] 13B shows an example of a cross section taken along the dashed line in FIG. 13A. A laminate including a positive electrode 750a, a solid electrolyte layer 750b, and a negative electrode 750c is enclosed and sealed within a package member 770a having a flat plate with an electrode layer 773a, a frame-shaped package member 770b, and a flat plate with an electrode layer 773b. The package members 770a, 770b, and 770c can be made of insulating materials, such as resin materials and ceramics.

[0163] The external electrode 771 is electrically connected to the positive electrode 750a via the electrode layer 773a and functions as a positive electrode terminal, while the external electrode 772 is electrically connected to the negative electrode 750c via the electrode layer 773b and functions as a negative electrode terminal.

[0164] By using the positive electrode active material 200A shown in the first embodiment or the positive electrode active material 200B shown in the second embodiment, an all-solid-state secondary battery having a high energy density and good output characteristics can be realized.

[0165] The content of this embodiment mode can be combined with the content of other embodiment modes as appropriate.

[0166] Embodiment 6 This embodiment is an example different from the cylindrical secondary battery shown in Fig. 5D. Fig. 14C shows an example of application to an electric vehicle (EV).

[0167] The electric vehicle is equipped with first batteries 1301a and 1301b as main driving secondary batteries, and a second battery 1311 that supplies power to an inverter 1312 that starts a motor 1304. The second battery 1311 is also called a cranking battery (also called a starter battery). The second battery 1311 only needs to have high output, and does not need to have a large capacity, and the capacity of the second battery 1311 is smaller than that of the first batteries 1301a and 1301b.

[0168] The internal structure of the first battery 1301a may be a wound type shown in Fig. 6A or 7C or a stacked type shown in Fig. 8A or 8B. The first battery 1301a may use the all-solid-state battery of Embodiment 5. By using the all-solid-state battery of Embodiment 5 for the first battery 1301a, a high capacity can be achieved, safety can be improved, and the battery can be made smaller and lighter.

[0169] In this embodiment, an example is shown in which two first batteries 1301a and 1301b are connected in parallel, but three or more batteries may be connected in parallel. Furthermore, if the first battery 1301a can store sufficient power, the first battery 1301b may be omitted. By configuring a battery pack having multiple secondary batteries, it is possible to extract large amounts of power. The multiple secondary batteries may be connected in parallel, in series, or in series after being connected in parallel. A plurality of secondary batteries is also called a battery pack.

[0170] In addition, in a secondary battery for vehicle use, a service plug or circuit breaker that can cut off high voltage without using tools is provided in the first battery 1301a in order to cut off power from multiple secondary batteries.

[0171] The power of the first batteries 1301a and 1301b is mainly used to rotate the motor 1304, but also supplies power to 42V system on-board components (electric power steering 1307, heater 1308, defogger 1309) via the DCDC 1306. When a rear motor 1317 is provided for the rear wheels, the first battery 1301a is also used to rotate the rear motor 1317.

[0172] In addition, the second battery 1311 supplies power to 14V system in-vehicle components (audio 1313, power windows 1314, lamps 1315) via the DCDC 1310.

[0173] The first battery 1301a will be described with reference to FIG. 14A.

[0174] FIG. 14A shows an example in which nine prismatic secondary batteries 1300 are combined into one battery pack 1415. Furthermore, nine prismatic secondary batteries 1300 are connected in series, with one electrode fixed by a fixing portion 1413 made of an insulator and the other electrode fixed by a fixing portion 1414 made of an insulator. While this embodiment shows an example in which the batteries are fixed by fixing portions 1413 and 1414, they may also be housed in a battery housing box (also called a casing). Because it is expected that a vehicle will be subjected to external vibrations or shaking (from the road surface), it is preferable to fix multiple secondary batteries using fixing portions 1413 and 1414 and a battery housing box. Furthermore, one electrode is electrically connected to a control circuit unit 1320 by wiring 1421. Furthermore, the other electrode is electrically connected to the control circuit unit 1320 by wiring 1422.

[0175] FIG. 14B shows an example of a block diagram of the battery pack 1415 shown in FIG. 14A.

[0176] The control circuit 1320 includes a switch unit 1324 including at least a switch for preventing overcharging and a switch for preventing overdischarging, a control circuit 1322 for controlling the switch unit 1324, and a voltage measurement unit for the first battery 1301a. The control circuit 1320 sets upper and lower voltage limits for the secondary battery used and limits the upper limit of the external current and the upper limit of the output current. The range between the lower and upper voltage limits of the secondary battery is within the recommended voltage range, and when the secondary battery is outside this range, the switch unit 1324 activates and functions as a protection circuit. The control circuit 1320 can also be called a protection circuit because it controls the switch unit 1324 to prevent overcharging and overdischarging. For example, if the control circuit 1322 detects a voltage that could cause overcharging, it turns off the switch unit 1324 to cut off the current. Furthermore, a PTC element may be provided in the charge / discharge path to provide a function for cutting off the current in response to an increase in temperature. The control circuit section 1320 also has an external terminal 1325 (+IN) and an external terminal 1326 (-IN).

[0177] The switch unit 1324 can be configured by combining n-channel transistors and p-channel transistors. The switch unit 1324 is not limited to a switch having a Si transistor using single crystal silicon, and may be, for example, Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), InP (indium phosphide), SiC (silicon carbide), ZnSe (zinc selenide), GaN (gallium nitride), GaO Ｘ The switch section 1324 may be formed of a power transistor having gallium oxide (x is a real number greater than 0).

[0178] The first batteries 1301a and 1301b primarily supply power to 42V (high-voltage) in-vehicle devices, while the second battery 1311 supplies power to 14V (low-voltage) in-vehicle devices. Lead-acid batteries are often used as the second battery 1311 due to their cost advantages. Lead-acid batteries have the disadvantage of being more self-discharged than lithium-ion secondary batteries and being prone to deterioration due to a phenomenon called sulfation. Using a lithium-ion secondary battery as the second battery 1311 offers the advantage of being maintenance-free, but after prolonged use, e.g., three years or more, there is a risk of abnormalities occurring that cannot be detected at the time of manufacture. In particular, if the second battery 1311, which starts the inverter, becomes inoperable, even if the first batteries 1301a and 1301b still have remaining capacity, the second battery 1311 is charged to maintain a full charge state by supplying power from the first battery to the second battery.

[0179] In this embodiment, an example in which lithium ion secondary batteries are used for both the first battery 1301a and the second battery 1311 is shown. A lead storage battery, an all-solid-state battery, or an electric double layer capacitor may be used for the second battery 1311. For example, the all-solid-state battery of Embodiment 3 may be used. By using the all-solid-state battery of Embodiment 3 for the second battery 1311, high capacity can be achieved, and reductions in size and weight can be achieved.

[0180] Furthermore, regenerative energy generated by the rotation of the tire 1316 is sent to the motor 1304 via the gear 1305, and is then charged into the second battery 1311 from the motor controller 1303 and the battery controller 1302 via the control circuit unit 1321. Alternatively, the first battery 1301a is charged from the battery controller 1302 via the control circuit unit 1320. Alternatively, the first battery 1301b is charged from the battery controller 1302 via the control circuit unit 1320. In order to efficiently charge the regenerative energy, it is desirable that the first batteries 1301a and 1301b be capable of rapid charging.

[0181] The battery controller 1302 can set the charging voltage and charging current of the first batteries 1301a and 1301b. The battery controller 1302 can set charging conditions in accordance with the charging characteristics of the secondary battery used, and can perform rapid charging.

[0182] Although not shown, when an external charger is connected, the charger's outlet or the charger's connection cable is electrically connected to the battery controller 1302. Power supplied from the external charger is charged to the first batteries 1301a and 1301b via the battery controller 1302. Some chargers are provided with a control circuit, and although the functions of the battery controller 1302 may not be used, it is preferable to charge the first batteries 1301a and 1301b via the control circuit unit 1320 to prevent overcharging. The control circuit unit 1320 may also be provided in the connection cable or the charger's connection cable. The control circuit unit 1320 is sometimes called an ECU (Electronic Control Unit). The ECU is connected to a CAN (Controller Area Network) provided in the electric vehicle. CAN is one of the serial communication standards used as an in-vehicle LAN. The ECU includes a microcomputer. The ECU uses a CPU or a GPU.

[0183] The external chargers installed at the charging stations are available with 100V outlets, 200V outlets, and three-phase 200V, 50kW outlets. It is also possible to charge using a contactless power supply system that receives power from external charging equipment.

[0184] When rapid charging is performed, a secondary battery that can withstand high voltage charging is desired in order to charge in a short time.

[0185] The secondary battery of this embodiment uses the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2. Furthermore, by using graphene as a conductive additive, a secondary battery with significantly improved electrical characteristics can be realized, which suppresses capacity reduction and maintains high capacity even when the electrode layer is thickened and the amount of graphene supported is increased. This is particularly effective for secondary batteries used in vehicles, and a vehicle with a long cruising range, specifically, a cruising distance of 500 km or more per charge, can be provided without increasing the ratio of the weight of the secondary battery to the total weight of the vehicle.

[0186] In particular, the secondary battery of the present embodiment described above can increase the operating voltage of the secondary battery by using the cathode active material 200A shown in embodiment 1 or the cathode active material 200B shown in embodiment 2, and can increase the usable capacity as the charging voltage increases. Furthermore, by using the cathode active material 200A shown in embodiment 1 or the cathode active material 200B shown in embodiment 2 in the cathode, a secondary battery for a vehicle having excellent cycle characteristics can be provided.

[0187] Next, an example in which a secondary battery according to one embodiment of the present invention is mounted on a vehicle, typically a transportation vehicle, will be described.

[0188] 5D, 7C, and 14A can be installed in a vehicle to realize a next-generation clean energy vehicle, such as a hybrid vehicle (HV), an electric vehicle (EV), or a plug-in hybrid vehicle (PHV). The secondary battery can also be installed in agricultural machinery, motorized bicycles including electrically assisted bicycles, motorcycles, electric wheelchairs, electric carts, small or large ships, submarines, fixed-wing and rotary-wing aircraft, rockets, artificial satellites, space probes, planetary probes, and transportation vehicles such as spacecraft. The secondary battery of one embodiment of the present invention can be a high-capacity secondary battery. Therefore, the secondary battery of one embodiment of the present invention is suitable for miniaturization and weight reduction and can be suitably used in transportation vehicles.

[0189] 15A to 15D illustrate examples of transportation vehicles using one embodiment of the present invention. The automobile 2001 shown in FIG. 15A is an electric automobile using an electric motor as a power source for traveling. Alternatively, it is a hybrid automobile that can appropriately select and use an electric motor or an engine as a power source for traveling. When a secondary battery is installed in a vehicle, an example of the secondary battery described in Embodiment 4 is installed in one or more locations. The automobile 2001 shown in FIG. 15A includes a battery pack 2200, which includes a secondary battery module to which multiple secondary batteries are connected. It is preferable that the automobile further include a charge control device electrically connected to the secondary battery module.

[0190] Furthermore, automobile 2001 can charge its secondary battery by receiving power from an external charging facility using a plug-in system or a contactless power supply system. The charging method and connector standard may be a predetermined system such as CHAdeMO (registered trademark) or Combo. The charging device may be a charging station installed in a commercial facility or a household power source. For example, plug-in technology can be used to charge an energy storage device installed in automobile 2001 using an external power supply. Charging can be performed by converting AC power to DC power via a conversion device, such as an AC-DC converter.

[0191] Although not shown, a power receiving device can be mounted on a vehicle and power can be supplied contactlessly from a ground-based power transmitting device to charge the vehicle. In the case of this contactless power supply method, by incorporating a power transmitting device into a road or an exterior wall, charging can be performed not only while the vehicle is stopped but also while the vehicle is moving. This contactless power supply method can also be used to transmit and receive power between two vehicles. Furthermore, solar cells can be installed on the exterior of the vehicle to charge the secondary battery while the vehicle is stopped and while moving. For such contactless power supply, an electromagnetic induction method or a magnetic field resonance method can be used.

[0192] 15B shows a large transport vehicle 2002 having an electrically controlled motor as an example of a transport vehicle. The secondary battery module of the transport vehicle 2002 is, for example, a four-cell unit of secondary batteries with a nominal voltage of 3.0 V to 5.0 V, with 48 cells connected in series to achieve a maximum voltage of 170 V. Apart from the number of secondary batteries constituting the secondary battery module of the battery pack 2201, the transport vehicle 2002 has the same functions as those shown in FIG. 15A, and therefore a description thereof will be omitted.

[0193] FIG. 15C shows, as an example, a large transport vehicle 2003 having an electrically controlled motor. The secondary battery module of the transport vehicle 2003 has, for example, 100 or more secondary batteries with a nominal voltage of 3.0 V or more and 5.0 V or less connected in series, with a maximum voltage of 600 V. By using a secondary battery with a positive electrode active material 200A shown in embodiment 1 or a positive electrode active material 200B shown in embodiment 2 as a positive electrode, a secondary battery with excellent rate characteristics and charge / discharge cycle characteristics can be manufactured, contributing to improved performance and a longer life of the transport vehicle 2003. Furthermore, except for the number of secondary batteries constituting the secondary battery module of the battery pack 2202, the same functions as those shown in FIG. 15A are provided, and therefore a description thereof will be omitted.

[0194] Fig. 15D shows, as an example, an aircraft 2004 having an engine that burns fuel. Since the aircraft 2004 shown in Fig. 15D has wheels for takeoff and landing, it can also be said to be part of a transportation vehicle, and has a battery pack 2203 that includes a secondary battery module formed by connecting multiple secondary batteries and the secondary battery module and a charge control device.

[0195] The secondary battery module of the aircraft 2004 is, for example, eight 4 V secondary batteries connected in series to produce a maximum voltage of 32 V. Apart from the number of secondary batteries constituting the secondary battery module of the battery pack 2203, it has the same functions as those in Fig. 15A, and therefore a description thereof will be omitted.

[0196] The content of this embodiment mode can be combined with the content of other embodiment modes as appropriate.

[0197] Embodiment 7 In this embodiment, an example in which a secondary battery which is one embodiment of the present invention is mounted in a building will be described with reference to FIGS. 16A and 16B.

[0198] 16A includes a power storage device 2612 including a secondary battery of one embodiment of the present invention and a solar panel 2610. The power storage device 2612 is electrically connected to the solar panel 2610 through a wiring 2611. The power storage device 2612 may also be electrically connected to a ground-mounted charging device 2604. The power obtained by the solar panel 2610 can be charged to the power storage device 2612. The power stored in the power storage device 2612 can be charged to a secondary battery included in the vehicle 2603 via the charging device 2604. The power storage device 2612 is preferably installed in an underfloor space. By installing the power storage device 2612 in the underfloor space, the space above the floor can be effectively utilized. Alternatively, the power storage device 2612 may be installed on the floor.

[0199] The power stored in the power storage device 2612 can also be supplied to other electronic devices in the house. Therefore, even when power cannot be supplied from a commercial power source due to a power outage, the power storage device 2612 of one embodiment of the present invention can be used as an uninterruptible power supply, enabling the use of electronic devices.

[0200] 16B illustrates an example of a power storage device according to one embodiment of the present invention. As illustrated in FIG. 16B , a power storage device 791 according to one embodiment of the present invention is installed in an underfloor space 796 of a building 799. The control circuit described in Embodiment 6 may be provided in the power storage device 791. The power storage device 791 can have a long lifetime by using a secondary battery in which the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 is used for its positive electrode.

[0201] A control device 790 is installed in the power storage device 791, and the control device 790 is electrically connected to the distribution board 703, the power storage controller 705 (also called the control device), the display 706, and the router 709 by wiring.

[0202] Electric power is sent from commercial power source 701 to distribution board 703 via service line attachment portion 710. Electric power is also sent to distribution board 703 from power storage device 791 and commercial power source 701, and distribution board 703 supplies the sent electric power to general load 707 and power storage load 708 via outlets (not shown).

[0203] The general load 707 is, for example, an electrical appliance such as a television or a personal computer, and the power storage load 708 is, for example, an electrical appliance such as a microwave oven, a refrigerator, or an air conditioner.

[0204] The power storage controller 705 includes a measurement unit 711, a prediction unit 712, and a planning unit 713. The measurement unit 711 has a function of measuring the amount of power consumed by the general load 707 and the power storage load 708 during a day (e.g., from midnight to midnight). The measurement unit 711 may also have a function of measuring the amount of power of the power storage device 791 and the amount of power supplied from the commercial power source 701. The prediction unit 712 has a function of predicting the amount of power demand to be consumed by the general load 707 and the power storage load 708 during the next day based on the amount of power consumed by the general load 707 and the power storage load 708 during the previous day. The planning unit 713 has a function of creating a plan for charging and discharging the power storage device 791 based on the amount of power demand predicted by the prediction unit 712.

[0205] The amount of power consumed by the general load 707 and the power storage load 708 measured by the measurement unit 711 can be confirmed on the display 706. It can also be confirmed on electrical appliances such as televisions and personal computers via the router 709. It can also be confirmed on portable electronic devices such as smartphones and tablets via the router 709. The amount of power demand for each time period (or each hour) predicted by the prediction unit 712 can also be confirmed on the display 706, the electrical appliances, and the portable electronic devices.

[0206] The content of this embodiment mode can be combined with the content of other embodiment modes as appropriate.

[0207] Embodiment 8 In this embodiment, an example in which a power storage device according to one embodiment of the present invention is mounted on a motorcycle or a bicycle will be described.

[0208] 17A illustrates an example of an electric bicycle using the power storage device of one embodiment of the present invention. The power storage device of one embodiment of the present invention can be applied to an electric bicycle 8700 illustrated in FIG. 17A. The power storage device of one embodiment of the present invention includes, for example, a plurality of storage batteries and a protection circuit.

[0209] The electric bicycle 8700 includes a power storage device 8702. The power storage device 8702 can supply electricity to a motor that assists a rider. The power storage device 8702 is portable and is shown in a state detached from the bicycle in FIG. 17B . The power storage device 8702 includes a plurality of built-in storage batteries 8701, which are included in the power storage device of one embodiment of the present invention, and the remaining battery charge can be displayed on a display unit 8703. The power storage device 8702 also includes a control circuit 8704 that can control charging or detect an abnormality of the secondary battery, an example of which is shown in Embodiment 6. The control circuit 8704 is electrically connected to the positive and negative electrodes of the storage battery 8701. The control circuit 8704 may be provided with the small-sized solid-state secondary battery shown in FIGS. 13A and 13B. By providing the small-sized solid-state secondary battery shown in FIGS. 13A and 13B in the control circuit 8704, power can be supplied to retain data in a memory circuit included in the control circuit 8704 for a long period of time. Furthermore, by combining the positive electrode active material 200A shown in the first embodiment or the positive electrode active material 200B shown in the second embodiment with a secondary battery using the positive electrode, a synergistic effect on safety can be obtained.

[0210] 17C illustrates an example of a two-wheeled vehicle using the power storage device of one embodiment of the present invention. A scooter 8600 illustrated in FIG. 17C includes a power storage device 8602, a side mirror 8601, and a turn signal light 8603. The power storage device 8602 can supply electricity to the turn signal light 8603. The power storage device 8602 includes a plurality of secondary batteries each using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for its positive electrode. This power storage device 8602 can have a high capacity and contribute to miniaturization.

[0211] 17C can store a power storage device 8602 in an under-seat storage compartment 8604. The power storage device 8602 can be stored in the under-seat storage compartment 8604 even if the under-seat storage compartment 8604 is small.

[0212] The content of this embodiment mode can be combined with the content of other embodiment modes as appropriate.

[0213] Embodiment 9 In this embodiment, an example of mounting a secondary battery according to one embodiment of the present invention in an electronic device will be described. Examples of electronic devices that mount a secondary battery include television sets (also referred to as televisions or television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones (also referred to as mobile phones or mobile phone devices), portable game consoles, personal digital assistants (PDAs), sound players, and large game consoles typified by pachinko machines. Examples of personal digital assistants include notebook personal computers, tablet devices, e-book readers, and mobile phones.

[0214] 18A shows an example of a mobile phone. The mobile phone 2100 includes a display portion 2102 built into a housing 2101, an operation button 2103, an external connection port 2104, a speaker 2105, and a microphone 2106. Note that the mobile phone 2100 includes a secondary battery 2107. By providing the secondary battery 2107 using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for its positive electrode, a high capacity can be achieved, and a configuration that can accommodate space saving due to miniaturization of the housing can be realized.

[0215] The mobile phone 2100 can execute a variety of applications, such as mobile phone calls, e-mail, document browsing and creation, music playback, internet communication, and computer games.

[0216] The operation button 2103 can be provided with various functions, such as time setting, power on / off operation, wireless communication on / off operation, silent mode activation / deactivation, and power saving mode activation / deactivation. For example, the functions of the operation button 2103 can be freely set by an operating system built into the mobile phone 2100.

[0217] The mobile phone 2100 is also capable of performing standardized short-range wireless communication, and can also make hands-free calls by communicating with a wirelessly enabled headset, for example.

[0218] The mobile phone 2100 also includes an external connection port 2104, which allows direct data exchange with other information terminals via a connector. Charging can also be performed via the external connection port 2104. Note that charging may be performed by wireless power supply without using the external connection port 2104.

[0219] The mobile phone 2100 preferably has a sensor, such as a fingerprint sensor, a pulse sensor, a human body sensor represented by a body temperature sensor, a touch sensor, a pressure sensor, or an acceleration sensor.

[0220] FIG. 18B illustrates an unmanned aerial vehicle 2300 having a plurality of rotors 2302. The unmanned aerial vehicle 2300 is sometimes called a drone. The unmanned aerial vehicle 2300 includes a secondary battery 2301 which is one embodiment of the present invention, a camera 2303, and an antenna (not shown). The unmanned aerial vehicle 2300 can be remotely controlled via the antenna. A secondary battery using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for its positive electrode has high energy density and high safety; therefore, it can be used safely for a long period of time and is suitable as a secondary battery to be installed in the unmanned aerial vehicle 2300.

[0221] Fig. 18C shows an example of a robot. A robot 6400 shown in Fig. 18C includes a secondary battery 6409, an illuminance sensor 6401, a microphone 6402, an upper camera 6403, a speaker 6404, a display unit 6405, a lower camera 6406, an obstacle sensor 6407, a movement mechanism 6408, and a computing unit.

[0222] The microphone 6402 has a function of detecting the user's voice and environmental sounds, and the speaker 6404 has a function of emitting sound. The robot 6400 can communicate with the user using the microphone 6402 and the speaker 6404.

[0223] The display unit 6405 has a function of displaying various information. The robot 6400 can display information desired by the user on the display unit 6405. The display unit 6405 may be equipped with a touch panel. The display unit 6405 may also be a detachable information terminal, which can be installed in a fixed position on the robot 6400 to enable charging and data transfer.

[0224] The upper camera 6403 and the lower camera 6406 have the function of capturing images of the surroundings of the robot 6400. Furthermore, the obstacle sensor 6407 can detect the presence or absence of obstacles in the direction of travel when the robot 6400 moves forward using the movement mechanism 6408. The robot 6400 can recognize the surrounding environment and move safely using the upper camera 6403, the lower camera 6406, and the obstacle sensor 6407.

[0225] The robot 6400 includes a secondary battery 6409 according to one embodiment of the present invention and a semiconductor device or an electronic component in an internal region thereof. A secondary battery using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for its positive electrode has high energy density and high safety, and therefore can be used safely for a long period of time. Therefore, the secondary battery is suitable as the secondary battery 6409 to be mounted on the robot 6400.

[0226] 18D shows an example of a cleaning robot. The cleaning robot 6300 includes a display unit 6302 arranged on the top surface of a housing 6301, a plurality of cameras 6303 arranged on the side surface, a brush 6304, an operation button 6305, a secondary battery 6306, and various sensors. Although not shown, the cleaning robot 6300 is provided with tires or a suction port. The cleaning robot 6300 can move by itself, detect dust 6310, and suck the dust from a suction port arranged on the bottom surface.

[0227] For example, the cleaning robot 6300 can analyze an image captured by the camera 6303 to determine the presence or absence of an obstacle such as a wall, furniture, or a step. Furthermore, when an object that may become entangled in the brush 6304, such as a wire, is detected through image analysis, the cleaning robot 6300 can stop rotation of the brush 6304. The cleaning robot 6300 includes a secondary battery 6306 according to one embodiment of the present invention and a semiconductor device or an electronic component in its internal region. A secondary battery using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 for its positive electrode has high energy density and high safety, and therefore can be used safely for a long period of time. Therefore, the secondary battery 6306 is suitable for use in the cleaning robot 6300.

[0228] The content of this embodiment mode can be combined with the content of other embodiment modes as appropriate.

[0229] In this example, a cobalt compound with an elemental ratio of nickel, cobalt, and manganese of Ni:Co:Mn=8:1:1 was obtained using the coprecipitation method according to the first embodiment, and then lithium and aluminum were added. After adding and mixing lithium, the compound was subjected to a first heat treatment at 500°C for 10 hours, then returned to room temperature and crushed, and then a second heat treatment at 800°C for 10 hours. Aluminum was then added, and a third heat treatment at 800°C for 2 hours was performed. The NCMA obtained contained 1 atm% Al relative to the total of nickel, manganese, cobalt, and oxygen.

[0230] As a comparative example, a cobalt compound having an elemental ratio of nickel, cobalt, and manganese of Ni:Co:Mn=8:1:1 was obtained using the coprecipitation method according to the first embodiment, and then lithium was added and mixed, followed by heat treatment at 800°C for 10 hours to obtain an NCM. The average particle size of the comparative example (NCM) was 11 μm.

[0231] On the other hand, the average particle size of this example (NCMA) is 9.6 μm.

[0232] A number of coin-type battery cells were fabricated using the positive electrode active material (NCMA) of this example, and their cycle characteristics were evaluated.

[0233] The positive electrode active material used for each sample was the positive electrode active material obtained by the method shown in embodiment 1. Acetylene black was used as the conductive additive, and they were mixed to prepare a slurry, which was then applied to an aluminum current collector.

[0234] After the slurry was applied to the current collector, the solvent was evaporated. Then, a pressure of 210 kN / m was applied, and then a pressure of 1467 kN / m was applied. A positive electrode was obtained by the above process. The amount of the positive electrode supported was approximately 7 mg / cm. ２ A cross-sectional observation photograph of a portion of the positive electrode is shown in Fig. 19. An enlarged view of a portion of the photograph is shown in Fig. 20.

[0235] The prepared positive electrode was used to prepare a coin-type battery cell of CR2032 type (diameter 20 mm, height 3.2 mm).

[0236] The counter electrode was made of lithium metal.

[0237] The sample electrolyte was 1 mol / L lithium hexafluorophosphate (LiPF ６ Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a volume ratio of EC:DEC = 3:7 using a solvent mixture containing ethylene carbonate (EC) and diethyl carbonate (DEC). 2 wt % of vinylene carbonate (VC) was added as an additive to the entire mixed solvent.

[0238] The separator was made of polypropylene having a thickness of 25 μm.

[0239] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0240] In evaluating the cycle characteristics, the charging voltage was 4.5 V, and the temperature of the incubator in which the half-cell was placed was 45°C. Charging was performed at a constant current (CC) / constant voltage (CV) at a rate of 0.5 C (1 C is 200 mA / g), and charging was terminated when the rate reached 0.05 C. Discharging was performed at a constant current (CC) at a rate of 0.5 C (1 C is 200 mA / g), and discharge was terminated when the voltage reached 2.5 V. A rest period may be provided between one discharge and the next charge; in this example, a 10-minute rest period was provided. As a cycle test to evaluate the cycle characteristics, the above charge and discharge were repeated 100 times.

[0241] 21A and 21B show the cycle characteristics when the measurement temperature is 25° C. In FIG. 21A, the vertical axis represents the discharge capacity, and in FIG. 21B, the vertical axis represents the discharge capacity retention rate.

[0242] 22A and 22B show the cycle characteristics when the measurement temperature is 45° C. In FIG. 22A, the vertical axis represents the discharge capacity, and in FIG. 22B, the vertical axis represents the discharge capacity retention rate.

[0243] In addition, in FIGS. 22A and 22B, the comparative example is an NCM in which the element ratio of nickel, cobalt, and manganese is Ni:Co:Mn=8:1:1.

[0244] From the results of FIG. 21B, it was confirmed that NCMA, which has a positive electrode active material with a higher crushing strength than NCM of the comparative example, has a higher capacity retention rate during charge cycles.

[0245] 170: coprecipitation synthesis apparatus, 171: reaction tank, 172: stirring unit, 173: stirring motor, 174: thermometer, 175: tank, 176: pipe, 177: pump, 180: tank, 181: pipe, 182: pump, 186: tank, 187: pipe, 188: pump, 190: control device, 192: aqueous solution, 200A: positive electrode active material, 200B: positive electrode active material, 300: secondary battery, 301: positive electrode can, 302: negative electrode can, 303: gasket, 304: positive electrode, 305: positive electrode current collector, 306: positive electrode active material layer, 307: negative electrode, 308: negative electrode current collector, 309: negative electrode active material layer, 310: separator separator, 312: washer, 313: ring-shaped insulator, 322: spacer, 400: secondary battery, 410: positive electrode, 411: positive electrode active material, 413: positive electrode current collector, 414: positive electrode active material layer, 420: solid electrolyte layer, 421: solid electrolyte, 430: negative electrode, 431: negative electrode active material, 433: negative electrode current collector, 434: negative electrode active material layer, 500: secondary battery, 501: positive electrode current collector, 502: positive electrode active material layer, 503: positive electrode, 504: negative electrode current collector, 505: negative electrode active material layer, 506: negative electrode, 507: separator, 509: exterior body, 510: positive electrode lead electrode, 511: negative electrode lead electrode, 513: secondary battery, 514: terminal, 515: seal, 517: antenna, 519: layer, 529: label, 531: secondary battery pack, 540: circuit board, 551: one side, 552: other side, 590: control circuit, 590a: circuit system, 590b: circuit system, 601: positive electrode cap, 602: battery can, 603: positive electrode terminal, 604: positive electrode, 605: separator, 606: negative electrode, 607: negative electrode terminal, 608: insulating plate, 609: insulating plate, 611: PTC element, 613: safety valve mechanism, 614: conductive plate, 615: power storage system, 616: secondary battery, 620: control circuit , 621: Wiring, 622: Wiring, 623: Wiring, 624: Conductor, 625: Insulator, 626: Wiring, 627: Wiring, 628: Conductive plate, 701: Commercial power supply, 703: Distribution board, 705: Energy storage controller, 706: Display, 707: General load, 708: Energy storage load, 709: Router, 710: Lead wire attachment part, 711: Measurement part, 712: Prediction part, 713: Planning part, 750a: Positive electrode, 750b: Solid electrolyte layer, 750c: Negative electrode, 751: Electrode plate, 752: Insulating tube, 753: Electrode plate, 761: Lower member, 762: Upper member, 764: Wing nut,765: O-ring, 766: insulator, 770a: packaging member, 770b: packaging member, 770c: packaging member, 771: external electrode, 772: external electrode, 773a: electrode layer, 773b: electrode layer, 790: control device, 791: power storage device, 796: underfloor space, 799: building, 890: aqueous solution, 892: aqueous solution, 893: aqueous solution, 894: aqueous solution, 895: aqueous solution, 896: aqueous solution, 901: mixed liquid, 902: mixed liquid, 904: mixture, 905: mixture, 906: mixed liquid, 908: mixture, 909: mixture, 910: compound, 911a: terminal, 9 11b: terminal, 913: secondary battery, 930: housing, 930a: housing, 930b: housing, 931: negative electrode, 931a: negative electrode active material layer, 932: positive electrode, 932a: positive electrode active material layer, 933: separator, 950: wound body, 950a: wound body, 951: terminal, 952: terminal, 1300: prismatic secondary battery, 1301a: battery, 1301b: battery, 1302: battery controller, 1303: motor controller, 1304: motor, 1305: gear, 1306: DCDC, 1307: electric power steering, 1308: heater, 1309: defogger, 1310: DCDC, 1311: battery, 1312: inverter, 1313: audio, 1314: power window, 1315: lamps, 1316: tires, 1317: rear motor, 1320: control circuit section, 1321: control circuit section, 1322: control circuit, 1324: switch section, 1325: external terminal, 1326: external terminal, 1413: fixing section, 1414: fixing section, 1415: battery pack, 1421: wiring, 1422: wiring, 2001: automobile, 2002: transport vehicle, 2003: transport vehicle, 2004: aircraft, 2100: mobile phone, 2101: housing, 2102 : Display unit, 2103: Operation buttons, 2104: External connection port, 2105: Speaker, 2106: Microphone, 2107: Secondary battery, 2200: Battery pack, 2201: Battery pack, 2202: Battery pack, 2203: Battery pack, 2300: Unmanned aerial vehicle, 2301: Secondary battery, 2302: Rotor, 2303: Camera, 2603: Vehicle, 2604: Charging device, 2610: Solar panel, 2611: Wiring, 2612: Power storage device, 6300: Cleaning robot, 6301: Housing, 6302: Display unit, 6303: Camera, 6304: Brush, 6305: Operation buttons,6306: Secondary battery, 6310: Garbage, 6400: Robot, 6401: Illuminance sensor, 6402: Microphone, 6403: Upper camera, 6404: Speaker, 6405: Display unit, 6406: Lower camera, 6407: Obstacle sensor, 6408: Moving mechanism, 6409: Secondary battery, 8600: Scooter, 8601: Side mirror, 8602: Power storage device, 8603: Turn signal light, 8604: Under-seat storage, 8700: Electric bicycle, 8701: Storage battery, 8702: Power storage device, 8703: Display unit, 8704: Control circuit,

Claims

1. A method for producing a positive electrode active material, supplying an aqueous solution containing a water-soluble salt of nickel, a water-soluble salt of cobalt, and a water-soluble salt of manganese, and an alkaline solution to a reaction vessel, and mixing the aqueous solutions in the reaction vessel to precipitate a cobalt compound; heating the first mixture of the cobalt compound and the lithium compound at a first temperature; After the heated first mixture is crushed or pulverized, further heating at a second temperature higher than the first temperature; a second mixture obtained by mixing the first mixture with an aluminum compound, and heating the second mixture at a third temperature to produce a positive electrode active material.

2. The method for producing a positive electrode active material according to claim 1 , wherein the third temperature is higher than the first temperature.

3. 3. The method for producing a positive electrode active material according to claim 1, further comprising the step of supplying an aqueous solution containing magnesium to the reaction vessel.

4. 3. The method for producing a positive electrode active material according to claim 1, further comprising the step of supplying an aqueous solution containing calcium to the reaction vessel.

5. 5. The method for producing a positive electrode active material according to claim 1, wherein the aqueous solution is dropped into the reaction tank at a dropping rate of 0.1 mL / min or more and 0.8 mL / min or less.

6. 6. The method for producing a positive electrode active material according to claim 1, wherein a mixed solution obtained by mixing the aqueous solution and the alkaline solution has a pH of 9 or more and 11 or less.

7. 7. The method for producing a positive electrode active material according to claim 1, further comprising the step of adding an aqueous solution containing glycine when the aqueous solution and the alkaline solution are mixed to precipitate the cobalt compound.

8. 8. The method for producing a positive electrode active material according to claim 1, wherein the first temperature range is 400° C. or more and 700° C. or less, and the second temperature range is higher than 700° C. and 1050° C. or less.