Patent Application
20240092658
One embodiment of the present invention relates to a positive electrode active material, a secondary battery, and a manufacturing method thereof. One embodiment of the present invention relates to a portable information terminal and a vehicle each including a secondary battery.
One embodiment of the present invention relates to an object or a manufacturing method. Alternatively, the present invention relates to a process, a machine, manufacture, or a composition of matter. 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.
Note that semiconductor devices in this specification mean all devices that can function by utilizing semiconductor characteristics, and an electro-optical device, a semiconductor circuit, and an electronic device are all semiconductor devices.
Note that power storage devices in this specification refer to any elements and devices having a function of storing power. For example, a power storage device (also referred to as a secondary battery) such as a lithium-ion secondary battery, a lithium-ion capacitor, and an electric double layer capacitor are included.
In recent years, lithium-ion secondary batteries, lithium-ion capacitors, air batteries, or a variety of power storage devices have been actively developed. In particular, demand for lithium-ion secondary batteries with high output and high energy density has rapidly grown with the development of the semiconductor industry, for portable information terminals typified by mobile phones, smartphones, and laptop computers, portable music players, digital cameras, medical equipment, next-generation clean energy vehicles typified by hybrid electric vehicles (HVs), electric vehicles (EVs), and plug-in hybrid electric vehicles (PHVs), and the like, and the lithium-ion secondary batteries are essential for today's information society as rechargeable energy supply sources.
Patent Document 1 discloses a positive electrode active material for a lithium-ion secondary battery with high capacity and excellent charge and discharge cycle performance.
[Patent Document 1] WO2020/099978
An object of one embodiment of the present invention is to provide a positive electrode active material with high charge and discharge capacity. Another object is to provide a positive electrode active material with high charge and discharge voltage. Another object is to provide a positive electrode active material that hardly deteriorates. Another object is to provide a novel positive electrode active material. Another object is to provide a secondary battery with high charge and discharge capacity. Another object is to provide a secondary battery with high charge and discharge voltage. Another object is to provide a highly safe or reliable secondary battery. Another object is to provide a secondary battery that hardly deteriorates. Another object is to provide a long-life secondary battery. Another object is to provide a novel secondary battery.
Another object of one embodiment of the present invention is to provide a novel material, a novel active material, a novel power storage device, or a manufacturing method thereof.
Note that the description of these objects does not preclude the existence of other objects. One embodiment of the present invention does not have to achieve all of these objects. Other objects can be derived from the description of the specification, the drawings, and the claims.
In a structure of the invention regarding the method disclosed in this specification, a positive electrode active material is manufactured in such a manner that after a cobalt compound (also referred to as a precursor) containing nickel, cobalt, and manganese is obtained by a coprecipitation method, a mixture obtained by mixing the cobalt compound and a lithium compound is heated at a first temperature and, after the heated mixture is ground or crushed, heating at a second temperature that is a temperature higher than the first temperature is further performed.
Moisture is released by the heating at the first temperature, and then heating is performed at the second temperature that is higher than the first temperature. Performing the heat treatment twice can improve the mixing state of the mixture, and when a secondary battery is fabricated with the mixture, voids of secondary particles can be reduced. Furthermore, the twice heat treatments can improve the crystallinity.
The first temperature is higher than or equal to 400° C. and lower than or equal to 700° C.
The second temperature is higher than 700° C. and lower than or equal to 1050° C.
In the case where aluminum is added as an additive element to the mixture, the lithium compound is added before the heat treatment at the first temperature, an aluminum compound is added after the second heat treatment, and third heat treatment is performed.
In a method for manufacturing a positive electrode active material, an aqueous solution in which a water-soluble nickel salt, a water-soluble cobalt salt, and a water-soluble manganese salt are dissolved and an alkaline solution are supplied to a reaction vessel and mixed in the reaction vessel to precipitate a cobalt compound; a first mixture of the cobalt compound and a lithium compound is heated at a first temperature; after the first mixture is ground or crushed, heating is further performed at a second temperature that is a temperature higher than the first temperature; and a second mixture obtained by mixing the first mixture and an aluminum compound is heated at a third temperature.
By the coprecipitation method for precipitating the cobalt compound, the aqueous solution in which the water-soluble nickel salt, the water-soluble cobalt salt, and the water-soluble manganese salt are dissolved and the alkaline solution are supplied to the reaction vessel, and mixing is performed in the reaction vessel to precipitate the cobalt compound (hydroxide containing cobalt, manganese, and nickel). The reaction is referred to as a neutralization reaction, an acid-base reaction, or a coprecipitation reaction in some cases. The compound containing at least nickel, cobalt, and manganese is referred to as a cobalt compound or a precursor of lithium cobalt oxide in some cases regardless of the contained amount of cobalt. The cobalt compound (hydroxide containing cobalt, manganese, and nickel) obtained by a coprecipitation reaction is referred to as a precursor in some cases. Then, a mixture of the cobalt compound and the lithium compound is obtained.
As the aqueous solution in which the water-soluble nickel salt is dissolved, a nickel sulfate aqueous solution or a nickel nitrate aqueous solution can be used.
As the aqueous solution in which the water-soluble cobalt salt is dissolved, a cobalt sulfate aqueous solution or a cobalt nitrate aqueous solution can be used.
As the aqueous solution in which the water-soluble manganese salt is dissolved, a manganese sulfate aqueous solution or a manganese nitrate aqueous solution can be used.
In the case where aluminum is further added as an additive element to the mixture, an aqueous solution containing aluminum is further supplied to the reaction vessel. In the case where magnesium is added as an additive element to the mixture, an aqueous solution containing magnesium is further supplied to the reaction vessel. In the case where calcium is added as an additive element to the mixture, an aqueous solution containing calcium is further supplied to the reaction vessel.
Moreover, the pH in the reaction vessel is preferably greater than or equal to 9.0 and less than or equal to 11.0, further preferably greater than or equal to 10.0 and less than or equal to 10.5.
When the aqueous solution and the alkaline solution are mixed to precipitate the cobalt compound, a chelating agent is added. Examples of the chelating agent include glycine, oxine, 1-nitroso-2-naphthol, 2-mercaptobenzothiazole, and EDTA (ethylenediaminetetraacetic acid). Note that two or more kinds selected from glycine, oxine, 1-nitroso-2-naphthol, and 2-mercaptobenzothiazole may be used. The chelating agent is dissolved in pure water, which is used as a chelate aqueous solution. The chelating agent serves as a complexing agent to form a chelate compound, and is preferred to a general complexing agent. Needless to say, such a complexing agent may be used instead of the chelating agent, and a general complexing agent such as an ammonia aqueous solution can be used.
The use of the chelate aqueous solution is preferable because it is easy to control the pH in the reaction vessel for obtaining a cobalt compound. Furthermore, the use of the chelate aqueous solution is preferable also because the chelate aqueous solution suppresses generation of unnecessary crystal nuclei and promotes crystal growth. Since generation of unnecessary crystal nuclei is suppressed to inhibit generation of fine particles, a hydroxide with good particle size distribution can be obtained. Furthermore, the use of the chelate aqueous solution can slow an acid-base reaction, so that the reaction gradually progresses to form a nearly spherical secondary particle. Glycine has a function of keeping the pH greater than or equal to 9.0 and less than or equal to 10.0 or the vicinity of the range. Using a glycine aqueous solution as the chelate aqueous solution is preferable because it is easy to control the pH of the reaction vessel when obtaining the cobalt compound. Furthermore, the concentration of glycine in the glycine aqueous solution is preferably greater than or equal to 0.05 mol/L and less than or equal to 0.09 mol/L in the aqueous solution in which the transition metal salts are dissolved.
The positive electrode active material obtained by the above-described method includes crystal having a hexagonal crystal layered structure. The crystal is not limited to a single crystal (also referred to as a crystallite). In the case where the crystal is polycrystalline, some crystallites gather to form a primary particle. The primary particle indicates a particle recognized as a single grain when observed with a SEM. The secondary particle indicates a group of aggregated primary particles. For the aggregation of the primary particles, there is no particular limitation on the bonding force between the plurality of primary particles. The bonding force may be any of covalent bonding, ionic bonding, a hydrophobic interaction, the Van der Waals force, and other molecular interactions, or a plurality of bonding forces may work together.
When the coprecipitation method is employed, the secondary particle is formed in some cases.
The crystal having a hexagonal crystal layered structure includes one or more selected from a first transition metal, a second transition metal, and a third transition metal. Specifically, NiCoMn-based material (also referred to as NCM) represented by LiNixCoyMnzO2 (x>0, y>0, z>0, 0.8<x+y+z<1.2) where the first transition metal is nickel, the second transition metal is cobalt, and the third transition metal is manganese, can be used. Specifically, 0.1x<y<8x and 0.1x<z<8x are preferably satisfied, for example. For example, x, y, and z preferably satisfy x:y:z=1:1:1 or the neighborhood thereof. Alternatively, for example, x, y, and z preferably satisfy x:y:z=5:2:3 or the neighborhood thereof. Alternatively, for example, x, y, and z preferably satisfy x:y:z=8:1:1 or the neighborhood thereof. Alternatively, for example, x, y, and z preferably satisfy x:y:z=9:0.5:0.5 or the neighborhood thereof. Alternatively, for example, x, y, and z preferably satisfy x:y:z=6:2:2 or the neighborhood thereof. Alternatively, for example, x, y, and z preferably satisfy x:y:z=1:4:1 or the neighborhood thereof.
The positive electrode active material obtained in the above-described method may contain one or more selected from a group formed of Al, Mg, Ca, Zr, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Nb, Mo, Sn, Ba, and La as necessary, in addition to the first transition metal, the second transition metal, and the third transition metal. In order that a secondary battery including the positive electrode active material has higher capacity retention rate after charge and discharge cycles, the positive electrode active material preferably contains Al, Mg, Ca, or Zr.
The secondary battery including the positive electrode active material is also a structure disclosed in this specification. The secondary battery includes a positive electrode including the positive electrode active material and a negative electrode including a negative electrode active material. In addition, a separator is included between the positive electrode and the negative electrode. The separator is used for preventing short circuit; thus, a secondary battery with high safety or high reliability can be provided.
In the case where aluminum is added as an additive element to the positive electrode active material, when the above-described method is regarded as the first method, there are other methods. The second method is a method in which aluminum is added in a state of an oxide before the first heat treatment. The third method is a method using an aqueous solution containing aluminum as one of aqueous solutions used for the coprecipitation method.
As described above, there are three methods of adding aluminum as an additive element to the positive electrode active material. In the case where aluminum is added as an additive element to the positive electrode active material, one or more of the above-described three methods can be employed. For example, in the case where a large amount of aluminum is added, the following procedure is possible: after aluminum is added with use of an aluminum-containing aqueous solution at the time of the coprecipitation method, lithium and aluminum are added and mixed; after heating is performed at a first temperature to release moisture, heating is performed at a second temperature that is higher than the first temperature; aluminum is added after the second heating; and then third heating is performed.
Performing heat treatment twice in one embodiment of the present invention improves the mixing state of the mixture, which can reduce voids of secondary particles when a secondary battery is fabricated. In addition, performing heat treatment three times, two times before the addition of aluminum and one time after the addition, can improve the crystallinity. Thus, a positive electrode active material with high capacity can be provided. A positive electrode active material which is relatively stable even when charge and discharge are repeated can be provided. A highly safe or highly reliable secondary battery can be provided.
Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not need to have all of these effects. Other effects will be apparent from the description of the specification, the drawings, and the claims, and other effects can be derived from the description of the specification, the drawings, and the claims.
Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following description, and it is readily understood by those skilled in the art that modes and details of the present invention can be modified in various ways. In addition, the present invention should not be construed as being limited to the description of the following embodiments.
In this embodiment, an example of a method for manufacturing a positive electrode active material 200A in which an additive element is added to a cobalt compound obtained by a coprecipitation method will be described with reference to
Employed in this embodiment is a process in which a precursor (also referred to as a coprecipitation precursor) where Co, Ni, or Mn exists in one particle is formed by a coprecipitation method, heating is performed twice after a Li salt is mixed to the coprecipitation precursor, and then aluminum is added.
As illustrated in
As the cobalt aqueous solution, an aqueous solution containing cobalt sulfate (e.g., CoSO4), cobalt chloride (e.g., CoCl2), cobalt nitrate (e.g., Co(NO3)2), cobalt acetate (e.g., C4H6COO4), cobalt alkoxide, an organocobalt complex, or hydrate of any of these is given. Alternatively, instead of the cobalt aqueous solution, an organic acid of cobalt, such as cobalt acetate, or hydrate of the organic acid of cobalt may be used. Note that in this specification, the organic acid includes citric acid, oxalic acid, formic acid, and butyric acid, in addition to acetic acid.
For example, an aqueous solution obtained by dissolving these in pure water can be used. The cobalt aqueous solution shows acidity, and thus can be referred to as an acid aqueous solution. The cobalt aqueous solution can be referred to as a cobalt source in a manufacturing process of a positive electrode active material.
As a nickel aqueous solution, an aqueous solution of nickel sulfate, nickel chloride, nickel nitrate, or hydrate of any of these can be used. Alternatively, an aqueous solution of an organic acid salt of nickel, such as nickel acetate, or hydrate of the organic acid salt of nickel can be used. Alternatively, an aqueous solution of nickel alkoxide or an organonickel complex can be used. The nickel aqueous solution can be referred to as a nickel source in a process of manufacturing a positive electrode active material.
As a manganese aqueous solution, an aqueous solution of manganese salt, such as manganese sulfate, manganese chloride, or manganese nitrate, or hydrate of any of these can be used. Alternatively, an aqueous solution of an organic acid salt of manganese, such as manganese acetate, or hydrate of the organic acid salt of manganese can be used. Alternatively, an aqueous solution of manganese alkoxide or an organomanganese complex can be used.
The above-described cobalt aqueous solution, nickel aqueous solution, and manganese aqueous solution may be prepared and mixed to form the aqueous solution 890; or nickel sulfate, cobalt sulfate, and manganese sulfate may be mixed and then mixed with water to form the aqueous solution 890, for example.
In this embodiment, nickel sulfate, cobalt sulfate, and manganese sulfate are weighed out to have desired amounts and mixed. The aqueous solution 890 obtained by mixing those is mixed with the aqueous solution 893 to form the mixed solution 901, and the mixed solution 902 of the aqueous solution 892, which is the alkaline solution, and the aqueous solution 894 is formed. As the aqueous solutions 893 and 894, aqueous solutions serving as chelating agents are used; however, the aqueous solutions 893 and 894 are not particularly limited thereto and may be pure water. The manganese aqueous solution can be referred to as a manganese source in a process of manufacturing a positive electrode active material.
As the alkaline solution, an aqueous solution containing sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia is given. For example, an aqueous solution obtained by dissolving these in pure water can be used. An aqueous solution in which two or more kinds selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide are dissolved in pure water may be used.
In the case where the aqueous solution 890 and the aqueous solution 892 are made to react by the coprecipitation method, the pH of the reaction system is set to greater than or equal to 9.0 and less than or equal to 11.0, preferably greater than or equal to 9.8 and less than or equal to 10.3. For example, in the case where the aqueous solution 892 is put into a reaction vessel and the aqueous solution 890 is dropped into the reaction vessel, the pH of the aqueous solution in the reaction vessel is preferably kept in the above range. The same applies to the case where the aqueous solution 890 is put into the reaction vessel and the aqueous solution 892 is dropped. The dropping rate of the aqueous solution 890 or the aqueous solution 892 is preferably greater than or equal to 0.1 mL/min. and less than or equal to 0.8 mL/min., in which case the pH condition can be controlled easily. The reaction vessel contains a reaction container.
An aqueous solution in the reaction vessel is preferably stirred with a stirring means. The stirring means includes a stirrer or an agitator blade. Two to six agitator blades can be provided; for example, in the case where four agitator blades are provided, they may be placed in across shape seen from above. The number of rotations of the stirring means is preferably greater than or equal to 800 rpm and less than or equal to 1200 rpm.
The temperature in the reaction vessel is adjusted to be higher than or equal to 50° C. and lower than or equal to 90° C. The dropping of the aqueous solution 892 or the aqueous solution 890 is preferably started after the temperature becomes the above temperature.
The reaction vessel preferably has an inert atmosphere. For example, in the case of a nitrogen atmosphere, a nitrogen gas is preferably introduced at a flow rate of 0.5 L/min. or more and 2 L/min. or less.
In the reaction vessel, a reflux condenser is preferably placed. The nitrogen gas can be released from the reaction vessel and water can be returned to the reaction vessel with use of the reflux condenser.
Through the above reaction, a cobalt compound is precipitated in the reaction vessel. Filtration is performed to collect the cobalt compound. After a reaction product precipitated in the reaction vessel is washed with pure water, an organic solvent (e.g., acetone) having a low boiling point is preferably added before the filtration is performed.
The cobalt compound after the filtration is preferably dried. For example, drying is performed under vacuum at higher than or equal to 60° C. and lower than or equal to 90° C. for longer than or equal to 0.5 hours and shorter than or equal to 3 hours. In this manner, the cobalt compound can be obtained.
The cobalt compound obtained through the above reaction includes cobalt hydroxide (e.g., Co(OH)2). The cobalt hydroxide after the filtration is obtained in the state of secondary particles which are aggregations of primary particles. Note that in this specification, a primary particle refers to a particle (lump) of the smallest unit having no grain boundary when being observed, for example, at a magnification of 5000 times with a SEM (scanning electron microscope). In other words, the primary particle means a particle of the smallest unit surrounded by a grain boundary. A secondary particle refers to a particle in which the primary particles are aggregated, partially sharing the grain boundary (the circumference of the primary particle), and are not easily separated from each other (a particle independent of the other particles). That is, the secondary particle has a grain boundary in some cases.
Next, a lithium compound is prepared.
As the lithium compound, a Li salt such as lithium hydroxide (e.g., LiOH), lithium carbonate (e.g., Li2CO3), or lithium nitrate (e.g., LiNO3) can be given, for example. In particular, a material having a low melting point among lithium compounds, such as lithium hydroxide (melting point: 462° C.), is preferably used. Since a positive electrode active material having a high nickel proportion is likely to cause cation mixing as compared to lithium cobalt oxide, first heating needs to be performed at a low temperature. Therefore, it is preferable to use a material having a low melting point.
In this embodiment, the cobalt compound and the lithium compound are weighed out to have desired amounts and mixed to form a mixture 904. For the mixing, a mortar or a stirring mixer is used.
Next, first heating is performed. An electric furnace or a rotary kiln furnace can be used as a firing device for the first heating.
Then, grinding or crushing is performed with a mortar to loosen the secondary particles fixed one another, and the ground or crushed mixture is collected. Furthermore, classification may be performed using a sieve. In this embodiment, a crucible made of aluminum oxide (also referred to as alumina) with a purity of 99.9% is used. It is suitable to collect the heated materials after the materials are transferred from the crucible to a mortar in order to prevent impurities from entering the materials. The mortar is suitably made of a material which is difficult to release impurities. Specifically, it is suitable to use a mortar made of alumina with a purity of 90% or higher, preferably 99% or higher.
Next, second heating is performed. An electric furnace or a rotary kiln furnace can be used as a firing device for the second heating.
The second temperature is at least higher than the first temperature and is preferably higher than 700° C. and lower than or equal to 1050° C. The time of the second heating is preferably longer than or equal to 1 hour and shorter than or equal to 20 hours. The second heating is preferably performed in an oxygen atmosphere, and in particular, preferably performed while oxygen is supplied. For example, the flow rate is 10 L/min. per liter of inner capacity of the furnace. Specifically, the heating is preferably performed in a state where a container containing the mixture 904 is covered with a lid.
Then, grinding or crushing is performed with a mortar to loosen the secondary particles fixed one another, and the ground or crushed mixture is collected. Furthermore, classification may be performed using a sieve.
Then, an obtained mixture 905 and a compound 910 are mixed.
As an additive element source, one or more selected from an aluminum salt, a magnesium salt, and a calcium salt are used. As the compound 910, one or more selected from aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, basic magnesium carbonate ((MgCO3)3Mg(OH)2.3H2O), calcium oxide, calcium carbonate, and calcium hydroxide are used. In this embodiment, an aluminum salt is used as the additive element source and aluminum hydroxide (Al(OH)3) is used as the compound 910. The compound 910 used as the additive element source is weighed out by a practitioner to be appropriately contained in a desired amount. It is desirable that aluminum, magnesium, or calcium be added at higher than or equal to 0.5 atm % and lower than or equal to 3 atm % with respect to the cobalt compound. Note that the concentration of the additive element here is based on the added amount in the formation of the secondary particles and might not correspond to the actually analyzed concentration.
Then, third heating is performed. The third temperature is at least higher than the first temperature and is preferably higher than 700° C. and lower than or equal to 1050° C. The time of the third heating is preferably shorter than that of the second heating and longer than or equal to 1 hour and shorter than or equal to 20 hours. The third heating is preferably performed in an oxygen atmosphere, and in particular, preferably performed while oxygen is supplied. For example, the flow rate is 10 L/min. per liter of inner capacity of the furnace. Specifically, the heating is preferably performed in a state where a container containing the mixture 905 is covered with a lid.
Then, grinding or crushing is performed with a mortar to loosen the secondary particles fixed one another, and the ground or crushed mixture is collected. Furthermore, classification may be performed using a sieve. With the crushing step, the grain size and/or the shape of the positive electrode active material 200A can be uniformized.
Through the above steps, the positive electrode active material 200A can be manufactured. The positive electrode active material 200A obtained through the above steps is Al-added NCM and thus referred to as NCMA in some cases.
One embodiment of the present invention is not limited to the procedure of the steps in
In
Moreover, the pH in the reaction vessel is preferably greater than or equal to 9.0 and less than or equal to 11.0, further preferably greater than or equal to 10.0 and less than or equal to 10.5.
Next, a lithium compound and the compound 910 as an oxide containing an additive element are prepared.
As illustrated in
After the mixture 908 is obtained, first heating is performed. An electric furnace or a rotary kiln furnace can be used as a firing device for the first heating.
Next, second heating is performed. An electric furnace or a rotary kiln furnace can be used as a firing device for the second heating.
The second temperature is at least higher than the first temperature and is preferably higher than 700° C. and lower than or equal to 1050° C. The time of the second heating is preferably longer than or equal to 1 hour and shorter than or equal to 20 hours. The second heating is preferably performed in an oxygen atmosphere, and in particular, preferably performed while oxygen is supplied. For example, the flow rate is 10 L/min. per liter of inner capacity of the furnace. Specifically, the heating is preferably performed in a state where a container containing the mixture 908 is covered with a lid.
Then, grinding or crushing is performed with a mortar to loosen the secondary particles fixed one another, and the ground or crushed mixture is collected. Furthermore, classification may be performed using a sieve.
Then, an obtained mixture 909 and the compound 910 are mixed.
Then, third heating is performed. The third temperature is at least higher than the first temperature and is preferably higher than 700° C. and lower than or equal to 1050° C. The time of the third heating is preferably longer than or equal to 1 hour and shorter than or equal to 20 hours. The third heating is preferably performed in an oxygen atmosphere, and in particular, preferably performed while oxygen is supplied. For example, the flow rate is 10 L/min. per liter of inner capacity of the furnace. Specifically, the heating is preferably performed in a state where a container containing the mixture 909 is covered with a lid.
Then, grinding or crushing is performed with a mortar to loosen the secondary particles fixed one another, and the ground or crushed mixture is collected. Furthermore, classification may be performed using a sieve. With the crushing step, the grain size and/or the shape of a positive electrode active material 200B can be uniformized.
Through the above steps, the positive electrode active material 200B can be manufactured. Since the process for obtaining the positive electrode active material 200B is partly different from the process for obtaining the positive electrode active material 200A in
This embodiment can be freely combined with the other embodiments.
In this embodiment, a coprecipitation apparatus that performs a coprecipitation method in the manufacturing methods in Embodiments 1 to 3 is described.
A coprecipitation synthesis apparatus 170 illustrated in
The procedure of a coprecipitation method surrounded by the chain line in
First, the aqueous solution 894 (chelating agent) is put in the reaction vessel 171, and then the mixed solution 901 and the aqueous solution 892 (alkaline solution) are dropped into the reaction vessel 171. The aqueous solution 192 in
Other components of the coprecipitation synthesis apparatus 170 illustrated in
The stirrer 172 can stir the aqueous solution 192 in the reaction vessel 171, and the stirrer motor 173 is included as a power source that makes the stirrer 172 rotate. The stirrer 172 includes a paddle-type agitator blade (denoted as a paddle blade), and the paddle blade includes two to six blades. The blade may have an inclination of greater than or equal to 40 degrees and less than or equal to 70 degrees.
The thermometer 174 can measure the temperature of the aqueous solution 192. The temperature of the reaction vessel 171 can be controlled using a thermoelectric element such that the temperature of the aqueous solution 192 is constant. An example of the thermoelectric element is a Peltier element. Although not shown, a pH meter is also provided in the reaction vessel 171, and the pH of the aqueous solution 192 can be measured.
Different aqueous solutions of source materials can be pooled in the tanks. For example, the tanks can be filled with the mixed solution 901 and the aqueous solution 892. A tank filled with the aqueous solution 894 serving as a filling liquid may be prepared. Each tank is equipped with a pump and an aqueous solution of a source material can be dropped into the reaction vessel 171 through a tube with use of the pump. The dropping amount of the aqueous solution of a source material, that is the amount of the delivered liquid, can be controlled with the pump. In addition to the pump, a valve may be provided for the tube 176, and the dropping amount of the aqueous solution of the source material, i.e., the amount of the delivered liquid may be controlled with the valve.
The control device 190 is electrically connected to the stirrer motor 173, the thermometer 174, the pump 177, the pump 182, and the pump 188, and can control the number of rotations of the stirrer 172, the temperature of the aqueous solution 192, and the dropping amounts of the aqueous solutions of source materials.
The number of rotations of the stirrer 172, specifically, the number of rotations of the paddle blade is preferably, for example, greater than or equal to 800 rpm and less than or equal to 1200 rpm. The stirring is preferably performed while the aqueous solution 192 is heated at a temperature higher than or equal to 50° C. and lower than or equal to 90° C. In the stirring, the mixed solution 901 is preferably dropped into the reaction vessel 171 at a constant rate. Needless to say, the rotation number of the paddle blade is not limited to a constant number, and can be appropriately adjusted. For example, the rotation number can be changed depending on the liquid amount of the reaction vessel 171. Moreover, the dropping rate of the mixed solution 901 can be adjusted. The dropping rate can be controlled to keep the pH of the reaction vessel 171 constant. The dropping rates may be controlled so that the aqueous solution 892 is dropped when the pH varies from a desired pH value during the dropping of the mixed solution 901. The pH value is greater than or equal to 9.0 and less than or equal to 11.0, preferably greater than or equal to 9.8 and less than or equal to 10.3.
Through the above process, a reaction product is precipitated in the reaction vessel 171. The reaction product includes a cobalt compound. This reaction can be referred to as coprecipitation or co-precipitation, and this step is referred to as a coprecipitation step in some cases.
This embodiment can be freely combined with the other embodiments.
An example of a coin-type secondary battery is described.
In
The positive electrode 304 has a stacked-layer structure in which a positive electrode active material layer 306 is formed over a positive electrode current collector 305.
To prevent a short circuit between the positive electrode and the negative electrode, the separator 310 and a ring-shaped insulator 313 are placed to cover the side surface and top surface of the positive electrode 304. The separator 310 has a larger flat surface area than the positive electrode 304.
In a coin-type secondary battery 300, the positive electrode can 301 doubling as a positive electrode terminal and the negative electrode can 302 doubling as a negative electrode terminal are insulated from each other and sealed by a gasket 303 made of polypropylene. The positive electrode 304 includes the positive electrode current collector 305 and the positive electrode active material layer 306 provided in contact with the positive electrode current collector 305. The negative electrode 307 includes a negative electrode current collector 308 and a negative electrode active material layer 309 provided in contact with the negative electrode current collector 308. The negative electrode 307 is not limited to having a stacked-layer structure, and lithium metal foil or lithium-aluminum alloy foil may be used.
Note that only one surface of each of the positive electrode 304 and the negative electrode 307 used for the coin-type secondary battery 300 is provided with an active material layer.
For the positive electrode can 301 and the negative electrode can 302, a metal having corrosion resistance to a liquid electrolyte, such as nickel, aluminum, or titanium, an alloy of such a metal, or an alloy of such a metal and another metal (e.g., stainless steel) can be used. Covering with nickel and aluminum is preferable in order to prevent corrosion due to the liquid electrolyte. The positive electrode can 301 and the negative electrode can 302 are electrically connected to the positive electrode 304 and the negative electrode 307, respectively.
The coin-type secondary battery 300 is manufactured in the following manner: the negative electrode 307, the positive electrode 304, and the separator 310 are immersed in the liquid electrolyte; as illustrated in
With the above-described structure, the coin-type secondary battery 300 can have high capacity, high charge and discharge capacity, and excellent cycle performance. Note that in the case of a secondary battery including a solid electrolyte layer between the negative electrode 307 and the positive electrode 304, the separator 310 is not necessarily provided.
An example of a cylindrical secondary battery is described with reference to
Inside the battery can 602 having a hollow cylindrical shape, a battery element in which a belt-like positive electrode 604 and a belt-like negative electrode 606 are wound with a belt-like separator 605 located therebetween is provided. Although not illustrated, the battery element is wound around a central axis. One end of the battery can 602 is close and the other end thereof is open. For the battery can 602, a metal having corrosion resistance to a liquid electrolyte, typified by nickel, aluminum, or titanium, an alloy of such a metal, and an alloy of such a metal and another metal (e.g., stainless steel) can be used. The battery can 602 is preferably covered with nickel and aluminum in order to prevent corrosion due to the liquid electrolyte. Inside the battery can 602, the battery element in which the positive electrode, the negative electrode, and the separator are wound is provided between a pair of insulating plates 608 and 609 that face each other. A nonaqueous electrolyte solution (not illustrated) is injected inside the battery can 602 provided with the battery element. A nonaqueous electrolyte solution similar to that for the coin-type secondary battery can be used.
Since a positive electrode and a negative electrode that are used for a cylindrical storage battery are wound, active materials are preferably formed on both surfaces of a current collector. Note that although
The positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 is used for the positive electrode 604, whereby the cylindrical secondary battery 616 can have high capacity, high charge and discharge capacity, and excellent cycle performance.
A positive electrode terminal (positive electrode current collecting lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collecting lead) 607 is connected to the negative electrode 606. Both the positive electrode terminal 603 and the negative electrode terminal 607 can be formed using a metal material of aluminum. The positive electrode terminal 603 and the negative electrode terminal 607 are resistance-welded to a safety valve mechanism 613 and the bottom of the battery can 602, respectively. The safety valve mechanism 613 is electrically connected to the positive electrode cap 601 through a PTC (Positive Temperature Coefficient) element 611. The safety valve mechanism 613 cuts off electrical connection between the positive electrode cap 601 and the positive electrode 604 when the internal pressure of the battery exceeds a predetermined threshold. The PTC element 611, which is a thermally sensitive resistor whose resistance increases as temperature rises, limits the amount of current by increasing the resistance, in order to prevent abnormal heat generation. Barium titanate (BaTiO3)-based semiconductor ceramic can be used for the PTC element.
The plurality of secondary batteries 616 may be connected in series after being connected in parallel.
A temperature control device may be provided between the plurality of secondary batteries 616. The secondary batteries 616 can be cooled with the temperature control device when overheated, whereas the secondary batteries 616 can be heated with the temperature control device when cooled too much. Thus, the performance of the power storage system 615 is less likely to be influenced by the outside temperature.
In
Structure examples of secondary batteries are described with reference to
A secondary battery 913 illustrated in
Note that as illustrated in
For the housing 930a, an insulating material of an organic resin can be used. In particular, when an organic resin is used for the side on which an antenna is formed, blocking of an electric field by the secondary battery 913 can be inhibited. When an electric field is not significantly blocked by the housing 930a, an antenna may be provided inside the housing 930a. For the housing 930b, a metal material can be used, for example.
As illustrated in
The positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 is used for the positive electrode 932, whereby the secondary battery 913 can have high capacity, high charge and discharge capacity, and excellent cycle performance.
The separator 933 has a larger width than the negative electrode active material layer 931a and the positive electrode active material layer 932a, and is wound to overlap with the negative electrode active material layer 931a and the positive electrode active material layer 932a. In terms of safety, the width of the negative electrode active material layer 931a is preferably larger than that of the positive electrode active material layer 932a. The wound body 950a having such a shape is preferable because of its high level of safety and high productivity.
As illustrated in
As illustrated in
As illustrated in
Next, examples of the appearance of a laminated secondary battery are illustrated in
Here, an example of a method for fabricating the laminated secondary battery whose external view is shown in
First, the negative electrode 506, the separator 507, and the positive electrode 503 are stacked.
After that, the negative electrodes 506, the separators 507, and the positive electrodes 503 are placed over the exterior body 509.
Subsequently, the exterior body 509 is folded along a portion shown by a dashed line, as illustrated in
Next, the liquid electrolyte (not illustrated) is introduced into the exterior body 509 from the inlet of the exterior body 509. The liquid electrolyte is preferably introduced in a reduced pressure atmosphere or in an inert atmosphere. Lastly, the inlet is sealed by bonding. In this manner, the laminated secondary battery 500 can be fabricated.
The positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 is used for the positive electrode 503, whereby the secondary battery 500 can have high capacity, high charge and discharge capacity, and excellent cycle performance.
Examples of a secondary battery pack of one embodiment of the present invention that is capable of wireless charging using an antenna will be described with reference to
A wound body or a stack may be included inside the secondary battery 513.
In the secondary battery pack 531, a control circuit 590 is provided over the circuit board 540 as illustrated in
Alternatively, as illustrated in
Note that the shape of the antenna 517 is not limited to a coil shape and may be a linear shape or a plate shape, for example. Furthermore, an antenna typified by a planar antenna, an aperture antenna, a traveling-wave antenna, an EH antenna, a magnetic-field antenna, or a dielectric antenna may be used. Alternatively, the antenna 517 may be a flat-plate conductor. The flat-plate conductor can serve as one of conductors for electric field coupling. That is, the antenna 517 can function as one of two conductors of a capacitor. Thus, electric power can be transmitted and received not only by an electromagnetic field or a magnetic field but also by an electric field.
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 blocking an electromagnetic field from the secondary battery 513, for example. As the layer 519, a magnetic material can be used, for example.
The contents of this embodiment can be freely combined with the contents of the other embodiments.
In this embodiment, an example in which an all-solid-state battery is fabricated using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 will be described.
As illustrated in
The positive electrode 410 includes a positive electrode current collector 413 and a positive electrode active material layer 414. The positive electrode active material layer 414 includes a positive electrode active material 411 and a solid electrolyte 421. The positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 is used as the positive electrode active material 411. The positive electrode active material layer 414 may include a conductive additive and a binder.
The solid electrolyte layer 420 includes the solid electrolyte 421. The solid electrolyte layer 420 is positioned between the positive electrode 410 and the negative electrode 430 and is a region that includes neither the positive electrode active material 411 nor a negative electrode active material 431.
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 the negative electrode active material 431 and the solid electrolyte 421. The negative electrode active material layer 434 may include a conductive additive and a binder. Note that when metal lithium is used as the negative electrode active material 431, metal lithium does not need to be processed into particles; thus, the negative electrode 430 that does not include the solid electrolyte 421 can be formed, as illustrated in
As the solid electrolyte 421 included in the solid electrolyte layer 420, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte can be used, for example.
The sulfide-based solid electrolyte includes a thio-LISICON-based material (Li10GeP2S12 or Li3.25Ge0.25P0.75S4), sulfide glass (70Li2S.30P2S5, 30Li2S.26B2S3.44LiI, 63Li2S.36SiS2.1Li3PO4, 57Li2S.38SiS2.5Li4SiO4, or 50Li2S.50GeS2), or sulfide-based crystallized glass (Li7P3S11 or Li3.25P0.95S4). The sulfide-based solid electrolyte has advantages of high conductivity of some materials, low-temperature synthesis, and ease of maintaining a path for electrical conduction after charge and discharge because of its relative softness.
The oxide-based solid electrolyte includes a material with a perovskite crystal structure (La2/3-xLi3xTiO3), a material with a NASICON crystal structure (Li1-yAlyTi2-y(PO4)3), a material with a garnet crystal structure (Li7La3Zr2O12), a material with a LISICON crystal structure (Li14ZnGe4O16), LLZO (Li7La3Zr2O12), oxide glass (Li3PO4—Li4SiO4 or 50Li4SiO4.50Li3BO3), or oxide-based crystallized glass (Li1.07Al0.69Ti1.46(PO4)3 or Li1.5Al0.5Ge1.5(PO4)3). The oxide-based solid electrolyte has an advantage of stability in the air.
The halide-based solid electrolyte includes LiAlCl4, LiInBr6, LiF, LiCl, LiBr, or LiI. Moreover, a composite material in which pores of porous aluminum oxide or porous silica are filled with such a halide-based solid electrolyte can be used as the solid electrolyte.
Alternatively, different solid electrolytes may be mixed and used.
In particular, Li1+xAlxTi2-x(PO4)3 (0[x[1) having a NASICON crystal structure (hereinafter, LATP) is preferable because it contains aluminum and titanium, each of which is the element the positive electrode active material used in the secondary battery 400 of one embodiment of the present invention is allowed to contain, and thus synergy of improving the cycle performance is expected. Moreover, higher productivity due to the reduction in the number of steps is expected. Note that in this specification, a NASICON crystal structure refers to a compound that is represented by M2(XO4)3 (M: transition metal; X: S, P, As, Mo, or W) and has a structure in which MO6 octahedrons and XO4 tetrahedrons that share common corners are arranged three-dimensionally.
An exterior body of the secondary battery 400 of one embodiment of the present invention can be formed using a variety of materials and have a variety of shapes, and preferably has a function of applying pressure to the positive electrode, the solid electrolyte layer, and the negative electrode.
The evaluation material is placed on an electrode plate 751, surrounded by an insulating tube 752, and pressed from above by the electrode plate 753.
A stack of a positive electrode 750a, a solid electrolyte layer 750b, and a negative electrode 750c is illustrated here as an example of the evaluation material, and its cross-sectional view is illustrated in
The electrode plate 751 and the lower component 761 that are electrically connected to the positive electrode 750a correspond to a positive electrode terminal. The electrode plate 753 and the upper component 762 that are electrically connected to the negative electrode 750c correspond to a negative electrode terminal. The electric resistance or the like can be measured while pressure is applied to the evaluation material through the electrode plate 751 and the electrode plate 753.
A package having excellent airtightness is preferably used as the exterior body of the secondary battery of one embodiment of the present invention. For example, a ceramic package or a resin package can be used. The exterior body is sealed preferably in a closed atmosphere where the outside air is blocked, for example, in a glove box.
The external electrode 771 is electrically connected to the positive electrode 750a through the electrode layer 773a and functions as a positive electrode terminal. The external electrode 772 is electrically connected to the negative electrode 750c through the electrode layer 773b and functions as a negative electrode terminal.
The use of the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 can achieve an all-solid-state secondary battery having a high energy density and favorable output characteristics.
The contents of this embodiment can be combined with the contents of the other embodiments as appropriate.
This embodiment is an example different from the cylindrical secondary battery of
The electric vehicle is provided with first batteries 1301a and 1301b as main secondary batteries for driving and a second battery 1311 that supplies electric power to an inverter 1312 for starting a motor 1304. The second battery 1311 is also referred to as a cranking battery (also referred to as a starter battery). The second battery 1311 only needs high output and high capacity is not so much needed; the capacity of the second battery 1311 is lower than that of the first batteries 1301a and 1301b.
The internal structure of the first battery 1301a may be the wound structure illustrated in
Although this embodiment describes an example in which the two first batteries 1301a and 1301b are connected in parallel, three or more batteries may be connected in parallel. In the case where the first battery 1301a can store sufficient electric power, the first battery 1301b may be omitted. By constituting a battery pack including a plurality of secondary batteries, large electric power can be extracted. The plurality of secondary batteries may be connected in parallel, connected in series, or connected in series after being connected in parallel. The plurality of secondary batteries are also referred to as an assembled battery.
In order to cut off electric power from the plurality of secondary batteries, the secondary batteries in the vehicle include a service plug or a circuit breaker that can cut off a high voltage without the use of equipment. The first battery 1301a is provided with such a service plug or a circuit breaker.
Electric power from the first batteries 1301a and 1301b is mainly used to rotate the motor 1304 and is supplied to in-vehicle parts for 42 V (an electric power steering 1307, a heater 1308, and a defogger 1309) through a DCDC 1306. Even in the case where there is a rear motor 1317 for rear wheels, the first battery 1301a is used to rotate the rear motor 1317.
The second battery 1311 supplies electric power to in-vehicle parts for 14 V (a stereo 1313, a power window 1314, and lamps 1315) through a DCDC 1310.
The first battery 1301a will be described with reference to
The control circuit portion 1320 includes a switch portion 1324 that includes at least a switch for preventing overcharge and a switch for preventing overdischarge, a control circuit 1322 for controlling the switch portion 1324, and a portion for measuring the voltage of the first battery 1301a. The control circuit portion 1320 is set to have the upper limit voltage and the lower limit voltage of the secondary battery to be used, and imposes the upper limit of current from the outside and the upper limit of output current to the outside. The range from the lower limit voltage to the upper limit voltage of the secondary battery falls within the recommended voltage range; when a voltage falls outside the range, the switch portion 1324 operates and functions as a protection circuit. The control circuit portion 1320 can also be referred to as a protection circuit because it controls the switch portion 1324 to prevent overdischarge and overcharge. For example, when the control circuit 1322 detects a voltage that is likely to cause overcharge, current is interrupted by turning off the switch in the switch portion 1324. Furthermore, a function of interrupting current in accordance with a temperature rise may be set by providing a PTC element in the charge and discharge path. The control circuit portion 1320 includes an external terminal 1325 (+IN) and an external terminal 1326 (−IN).
The switch portion 1324 can be formed by a combination of an n-channel transistor and a p-channel transistor. The switch portion 1324 is not limited to a switch including a Si transistor using single crystal silicon; the switch portion 1324 may be formed using, for example, a power transistor containing Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), InP (indium phosphide), SiC (silicon carbide), ZnSe (zinc selenide), GaN (gallium nitride), or GaOx (gallium oxide, where x is a real number greater than 0).
The first batteries 1301a and 1301b mainly supply electric power to in-vehicle parts for 42 V (for a high-voltage system), and the second battery 1311 supplies electric power to in-vehicle parts for 14 V (for a low-voltage system). Lead storage batteries are usually used for the second battery 1311 due to cost advantage. Lead storage batteries have disadvantages compared with lithium-ion secondary batteries in that they have a larger amount of self-discharge and are more likely to deteriorate due to a phenomenon called sulfation. There is an advantage that the second battery 1311 can be maintenance-free when a lithium-ion secondary battery is used; however, in the case of long-term use, for example three years or more, anomaly that cannot be determined at the time of manufacturing might occur. In particular, when the second battery 1311 that starts the inverter becomes inoperative, the motor cannot be started even when the first batteries 1301a and 1301b have remaining capacity; thus, in order to prevent this, in the case where the second battery 1311 is a lead storage battery, the second battery is supplied with electric power from the first battery to constantly maintain a fully-charged state.
In this embodiment, an example in which a lithium-ion secondary battery is used as both the first battery 1301a and the second battery 1311 is described. As the second battery 1311, a lead storage battery, an all-solid-state battery, or an electric double layer capacitor may be used. For example, the all-solid-state battery in Embodiment 3 may be used. The use of the all-solid-state battery in Embodiment 3 as the second battery 1311 can achieve high capacity and reduction in size and weight.
Regenerative energy generated by rolling of tires 1316 is transmitted to the motor 1304 through a gear 1305, and is stored in the second battery 1311 from a motor controller 1303 and a battery controller 1302 through a control circuit portion 1321. Alternatively, the regenerative energy is stored in the first battery 1301a from the battery controller 1302 through the control circuit portion 1320. Alternatively, the regenerative energy is stored in the first battery 1301b from the battery controller 1302 through the control circuit portion 1320. For efficient charge with regenerative energy, the first batteries 1301a and 1301b are desirably capable of fast charging.
The battery controller 1302 can set the charge voltage and charge current of the first batteries 1301a and 1301b. The battery controller 1302 can set charge conditions in accordance with charge characteristics of a secondary battery to be used, so that fast charge can be performed.
Although not illustrated, in the case of connection to an external charger, an outlet of the charger or a connection cable of the charger is electrically connected to the battery controller 1302. Electric power supplied from the external charger is stored in the first batteries 1301a and 1301b through the battery controller 1302. Some chargers are provided with a control circuit, in which case the function of the battery controller 1302 is not used; to prevent overcharge, the first batteries 1301a and 1301b are preferably charged through the control circuit portion 1320. In addition, a connection cable or the connection cable of the charger is sometimes provided with a control circuit. The control circuit portion 1320 is also referred to as an ECU (Electronic Control Unit). The ECU is connected to a CAN (Controller Area Network) provided in the electric vehicle. The CAN is a type of a serial communication standard used as an in-vehicle LAN. The ECU includes a microcomputer. Moreover, the ECU uses a CPU or a GPU.
External chargers installed at charge stations have a 100 V outlet, a 200 V outlet, or a three-phase 200 V outlet with 50 kW. Furthermore, charge can be performed with electric power supplied from external charge equipment by a contactless power feeding method.
For fast charge, secondary batteries that can withstand high-voltage charge have been desired to perform charge in a short time.
The above-described secondary battery in this embodiment uses the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2. Moreover, it is possible to achieve a secondary battery in which graphene is used as a conductive additive, an electrode layer is formed thick to increase the loading amount while suppressing a reduction in capacity, and the electrical characteristics are significantly improved in synergy with maintenance of high capacity. This secondary battery is particularly effectively used in a vehicle; it is possible to provide a vehicle that has a long cruising range, specifically one charge mileage of 500 km or greater, without increasing the proportion of the weight of the secondary battery to the weight of the entire vehicle.
Specifically, in the above-described secondary battery in this embodiment, the use of the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 can increase the operating voltage of the secondary battery, and the increase in charge voltage can increase the available capacity. Moreover, using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 in the positive electrode can provide an automotive secondary battery having excellent cycle performance.
Next, examples in which the secondary battery of one embodiment of the present invention is mounted on a vehicle, typically a transport vehicle, will be described.
Mounting the secondary battery illustrated in any one of
The motor vehicle 2001 can be charged when the secondary battery included in the motor vehicle 2001 is supplied with electric power from external charge equipment by a plug-in system or a contactless charge system. In charging, a given method such as CHAdeMO (registered trademark) or Combined Charging System may be employed as a charge method and the standard of a connector, as appropriate. A charging device may be a charging station provided in a commerce facility or a power source in a house. For example, with the use of the plug-in system, the power storage device mounted on the motor vehicle 2001 can be charged by being supplied with electric power from the outside. Charge can be performed by converting AC power into DC power through a converter typified by an ACDC converter.
Although not illustrated, the vehicle can include a power receiving device so as to be charged by being supplied with electric power from an above-ground power transmitting device in a contactless manner. For the contactless power feeding system, by fitting a power transmitting device in a road or an exterior wall, charge can be performed not only when the vehicle is stopped but also when driven. In addition, the contactless power feeding system may be utilized to perform transmission and reception of electric power between two vehicles. Furthermore, a solar cell may be provided in the exterior of the vehicle to charge the secondary battery when the vehicle stops and moves. To supply electric power in such a contactless manner, an electromagnetic induction method or a magnetic resonance method can be used.
The secondary battery module of the aircraft 2004 has eight 4 V secondary batteries connected in series, which has the maximum voltage of 32 V, for example. The battery pack 2203 has the same function as that in
The contents of this embodiment can be combined with the contents of the other embodiments as appropriate.
In this embodiment, examples in which the secondary battery of one embodiment of the present invention is mounted on a building will be described with reference to
A house illustrated in
The electric power stored in the power storage device 2612 can also be supplied to other electronic devices in the house. Thus, with the use of the power storage device 2612 of one embodiment of the present invention as an uninterruptible power source, electronic devices can be used even when electric power cannot be supplied from a commercial power source due to power failure.
The power storage device 791 is provided with a control device 790, and the control device 790 is electrically connected to a distribution board 703, a power storage controller 705 (also referred to as a control device), an indicator 706, and a router 709 through wirings.
Electric power is transmitted from a commercial power source 701 to the distribution board 703 through a service wire mounting portion 710. Moreover, electric power is transmitted to the distribution board 703 from the power storage device 791 and the commercial power source 701, and the distribution board 703 supplies the transmitted electric power to a general load 707 and a power storage load 708 through outlets (not illustrated).
The general load 707 is, for example, an electric device typified by a TV or a personal computer. The power storage load 708 is, for example, an electric device typified by a microwave, a refrigerator, or an air conditioner.
The power storage controller 705 includes a measuring portion 711, a predicting portion 712, and a planning portion 713. The measuring portion 711 has a function of measuring the amount of electric power consumed by the general load 707 and the power storage load 708 during a day (e.g., from midnight to midnight). The measuring portion 711 may have a function of measuring the amount of electric power of the power storage device 791 and the amount of electric power supplied from the commercial power source 701. The predicting portion 712 has a function of predicting, on the basis of the amount of electric power consumed by the general load 707 and the power storage load 708 during a given day, the demand for electric power consumed by the general load 707 and the power storage load 708 during the next day. The planning portion 713 has a function of making a charge and discharge plan of the power storage device 791 on the basis of the demand for electric power predicted by the predicting portion 712.
The amount of electric power consumed by the general load 707 and the power storage load 708 and measured by the measuring portion 711 can be checked with the indicator 706. It can be checked with an electric device typified by a TV or a personal computer through the router 709. Furthermore, it can be checked with a portable electronic terminal typified by a smartphone or a tablet through the router 709. With the indicator 706, the electric device, or the portable electronic terminal, for example, the demand for electric power depending on a time period (or per hour) that is predicted by the predicting portion 712 can be checked.
The contents of this embodiment can be combined with the contents of the other embodiments as appropriate.
In this embodiment, examples in which a motorcycle or a bicycle is provided with the power storage device of one embodiment of the present invention will be described.
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
In the motor scooter 8600 illustrated in
The contents of this embodiment can be combined with the contents of the other embodiments as appropriate.
In this embodiment, examples of electronic devices each including the secondary battery of one embodiment of the present invention will be described. Examples of the electronic device including the secondary battery include a television device (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a cellular phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine typified by a pachinko machine. Examples of the portable information terminal include a laptop personal computer, a tablet terminal, an e-book reader, and a mobile phone.
The mobile phone 2100 is capable of executing a variety of applications typified by mobile phone calls, e-mailing, viewing and editing texts, music reproduction, Internet communication, and a computer game.
With the operation button 2103, a variety of functions typified by time setting, power on/off, on/off of wireless communication, setting and cancellation of a silent mode, and setting and cancellation of a power saving mode can be performed. For example, the functions of the operation button 2103 can be set freely by the operating system incorporated in the mobile phone 2100.
The mobile phone 2100 can employ near field communication conformable to a communication standard. For example, mutual communication between the mobile phone 2100 and a headset capable of wireless communication enables hands-free calling.
Moreover, the mobile phone 2100 includes the external connection port 2104, and data can be directly transmitted to and received from another information terminal via a connector. In addition, charge can be performed via the external connection port 2104. Note that the charge operation may be performed by wireless power feeding without using the external connection port 2104.
The mobile phone 2100 preferably includes a sensor. As the sensor, a human body sensor typified by a fingerprint sensor, a pulse sensor, or a temperature sensor, a touch sensor, a pressure sensitive sensor, or an acceleration sensor is preferably mounted, for example.
The microphone 6402 has a function of detecting a speaking voice of a user and an environmental sound. The speaker 6404 has a function of outputting sound. The robot 6400 can communicate with the user using the microphone 6402 and the speaker 6404.
The display portion 6405 has a function of displaying various kinds of information. The robot 6400 can display information desired by the user on the display portion 6405. The display portion 6405 may be provided with a touch panel. Moreover, the display portion 6405 may be a detachable information terminal, in which case charge and data communication can be performed when the display portion 6405 is set at the home position of the robot 6400.
The upper camera 6403 and the lower camera 6406 each have a function of taking an image of the surroundings of the robot 6400. The obstacle sensor 6407 can detect an obstacle in the direction where the robot 6400 advances with the moving mechanism 6408. The robot 6400 can move safely by recognizing the surroundings with the upper camera 6403, the lower camera 6406, and the obstacle sensor 6407.
The robot 6400 further includes, in its inner region, the secondary battery 6409 of one embodiment of the present invention and a semiconductor device or an electronic component. A secondary battery including a positive electrode using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 has high energy density and a high level of safety, and thus can be used safely for a long time over a long period of time and is preferable as the secondary battery 6409 included in the robot 6400.
For example, the cleaning robot 6300 can determine whether there is an obstacle such as a wall, furniture, or a step by analyzing images taken by the cameras 6303. In the case where the cleaning robot 6300 detects an object, typified by a wire, that is likely to be caught in the brush 6304 by image analysis, the rotation of the brush 6304 can be stopped. The cleaning robot 6300 includes, in its inner region, the secondary battery 6306 of one embodiment of the present invention and a semiconductor device or an electronic component. A secondary battery including a positive electrode using the positive electrode active material 200A described in Embodiment 1 or the positive electrode active material 200B described in Embodiment 2 has high energy density and a high level of safety, and thus can be used safely for a long time over a long period of time and is preferable as the secondary battery 6306 included in the cleaning robot 6300.
The contents of this embodiment can be combined with the contents of the other embodiments as appropriate.
In this example, a cobalt compound containing nickel, cobalt, and manganese at an element ratio Ni:Co:Mn=8:1:1 was obtained by a coprecipitation method in accordance with Embodiment 1, and then lithium and aluminum were added. After lithium was added and mixed, first heat treatment was performed at 500° C. for 10 hours, the temperature was returned to room temperature and crushing was performed, and then second heat treatment was performed at 800° C. for 10 hours. Then, aluminum was added and third heat treatment was performed at 800° C. for 2 hours. NCMA was obtained by adding Al at 1 atm % with respect to the total of nickel, manganese, cobalt, and oxygen.
As a comparative example, NCM was obtained in such a manner that after a cobalt compound containing nickel, cobalt, and manganese at an element ratio Ni:Co:Mn=8:1:1 was obtained by a coprecipitation method in accordance with Embodiment 1, lithium was added and mixed and then heat treatment was performed at 800° C. for 10 hours. The average particle diameter of the comparative example (NCM) is 11 μm.
The average particle diameter of this example (NCMA) is 9.6 μm.
A plurality of coin-type battery cells were fabricated using the positive electrode active material of this example (NCMA), and their cycle performance was evaluated.
The positive electrode active material obtained by the method described in Embodiment 1 was used as positive electrode active materials of the samples. Acetylene black was used as a conductive additive, mixing was performed to form a slurry, and the slurry was applied onto a current collector of aluminum.
After the slurry was applied onto the current collector, a solvent was volatilized. After that, pressure was applied at 210 kN/m, and then pressure was further applied at 1467 kN/m. Through the above process, the positive electrode was obtained. The loading amount of the positive electrode was approximately 7 mg/cm2.
Using the formed positive electrodes, CR2032 type coin-type battery cells (a diameter of 20 mm, a height of 3.2 mm) were fabricated.
A lithium metal was used for a counter electrode.
As an electrolyte of the samples, 1 mol/L of lithium hexafluorophosphate (LiPF6) was used, and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at EC:DEC=3:7 (volume ratio). Furthermore, vinylene carbonate (VC) was added as an additive at 2 wt % with respect to the total solvent mixed above.
As a separator, 25-μm-thick polypropylene was used.
A positive electrode can and a negative electrode can that were formed using stainless steel (SUS) were used.
In the evaluation of the cycle performance, the charge voltage was set at 4.5 V, and the temperature of a constant-temperature unit in which the half cell was placed was set at 45° C. Charge was performed by constant current (CC)/constant voltage (CV) at a rate of 0.5 C (1 C was 200 mA/g) and finished when the rate was 0.05 C. Discharge was performed by constant current (CC) at a rate of 0.5 C (1 C was 200 mA/g) and finished when the voltage was 2.5 V. Downtime may be provided between the discharge and the next charge; a 10-minute downtime was provided in this example. As a cycle test for evaluating the cycle performance, the charge and the discharge described above were repeated 100 times.
Note that the comparative example in
From the results of
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-020922 | Feb 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/050839 | 2/1/2022 | WO |
