Method for producing positive electrode active material particles

Abstract

To provide positive electrode active material particles that suppress capacity degradation during charge-discharge cycles; or to provide a high-capacity secondary battery; or to provide a secondary battery with excellent charge-discharge characteristics; or to provide a safe or reliable secondary battery; or to provide a novel material, active material particles, or energy storage device. [Solution] A positive electrode active material particle 100 having a first region 101 and a second region 102, the second region having a region in contact with the outside of the first region, the first region having lithium, one or more elements M selected from cobalt, manganese, and nickel, and oxygen, the second region having element M, oxygen, magnesium, and fluorine, the atomic ratio of lithium to element M (Li / M) measured by X-ray photoelectron spectroscopy being 0.5 or more and 0.85 or less, and the atomic ratio of magnesium to element M (Mg / M) measured by X-ray photoelectron spectroscopy being 0.2 or more and 0.5 or less.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a product, a method, or a method of manufacture; or, the present invention relates to a process , relating to machines, manufacturers, or compositions of matter One aspect of the present invention relates to semiconductor devices, display devices, light-emitting devices, energy storage devices, lighting devices, and electronic devices. , or relating to methods for manufacturing them. Or relating to electronic devices and their operating systems. Regarding Tem.

[0002] In this specification, "energy storage device" refers to all elements and devices that have an energy storage function. For example, rechargeable batteries (also called secondary batteries) such as lithium-ion secondary batteries, This includes um ion capacitors and electric double-layer capacitors.

[0003] Furthermore, in this specification, "electronic equipment" refers to all devices that have an energy storage device. Electro-optical devices and information terminal devices with energy storage devices are all electronic devices. [Background technology]

[0004] In recent years, various energy storage technologies have emerged, such as lithium-ion secondary batteries, lithium-ion capacitors, and air batteries. The development of devices is thriving. In particular, high-power, high-capacity lithium-ion secondary batteries are being developed. Mobile phones, smartphones, or other portable information devices such as laptop computers, and portable sound devices. Easy players, digital cameras, medical equipment, or hybrid electric vehicles (HEVs), electric vehicles Next-generation clean energy such as electric vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs) - In line with the development of the semiconductor industry, such as the automotive sector, demand for rechargeable energy is rapidly expanding. It has become indispensable to modern information society as a source of supply.

[0005] The characteristics required of lithium-ion secondary batteries include further increases in capacity and cycle life. These improvements include enhanced performance, safety in various operating environments, and improved long-term reliability.

[0006] To improve the cycle characteristics and increase the capacity of lithium-ion secondary batteries, the cathode active material Improvements are being considered (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-018914 [Patent Document 2] Japanese Patent Publication No. 2016-076454 [Overview of the project] [Problems that the invention aims to solve]

[0008] Thus, lithium-ion secondary batteries and the positive electrode active materials used therein have capacity, saturation, etc. There is room for improvement in various aspects such as cycle characteristics, charge / discharge characteristics, reliability, safety, and cost. It remains.

[0009] One aspect of the present invention, when used in a lithium-ion secondary battery, enables the charge-discharge cycle One of the objectives is to provide positive electrode active material particles that suppress capacity reduction. One aspect of the present invention aims to provide a high-capacity secondary battery. One aspect of this invention is to provide a secondary battery with excellent charge and discharge characteristics. One aspect of this invention aims to provide a safe or highly reliable secondary battery.

[0010] Alternatively, one aspect of the present invention aims to provide a novel substance, an active material particle, an energy storage device, or a method for producing them. One of the problems is to achieve this.

[0011] Note that the description of these problems does not preclude the existence of other problems. One aspect of the present invention is not required to solve all of these problems. Other problems can be extracted from the description of the specification, drawings, and claims.

Means for Solving the Problems

[0012] One aspect of the present invention is a positive electrode active material particle having a first region and a second region, where the second region has a region that contacts the outside of the first region. The first region contains lithium, element M and oxygen, and element M is one or more elements selected from cobalt, manganese, and nickel. The second region contains element M, oxygen, magnesium, and fluorine. The atomic ratio of lithium to element M (Li / M) measured by X-ray photoelectron spectroscopy is 0.5 or more and 0.85 or less, and the atomic ratio of magnesium to element M (Mg / M) measured by X-ray photoelectron spectroscopy is 0.2 or more and 0.5 or less. X-ray photoelectron spectroscopy is used to analyze, for example, the surface of the positive electrode active material particle. This is a positive electrode active material particle. X-ray photoelectron spectroscopy analyzes, for example, from the surface of the positive electrode active material particle.

[0013] In the above configuration, the thickness of the second region is preferably 0.5 nm or more and 50 nm or less.

[0014] In the above configuration, it is preferable that the first region has a layered rock salt-type crystal structure and the second region has a rock <00001​​​​Furthermore, in the above configuration, the crystal structure of the first region is represented by the space group R-3m, and the second region The crystal structure of the region is preferably represented by the space group Fm-3m.

[0016] Furthermore, in the above configuration, the number of fluorine atoms relative to element M measured by X-ray photoelectron spectroscopy The ratio (F / M) is preferably between 0.02 and 0.15.

[0017] Furthermore, in the above configuration, it is preferable that element M is cobalt.

[0018] Alternatively, one aspect of the present invention relates to positive electrode active material particles having a first region and a second region. The second region has a region adjacent to the outside of the first region, and the first region is lithium and It contains element M and oxygen, and element M is selected from cobalt, manganese, and nickel. The second region consists of one or more elements, and includes elements M, oxygen, magnesium, and fluorine. The particles are formed using multiple raw materials, and the atomic number of element M present in the multiple raw materials The ratio of the total number of lithium atoms in multiple raw materials to the total number of lithium atoms (Li / M) is 1.02. These are positive electrode active material particles that are larger than 1.05 and smaller than 1.05.

[0019] Furthermore, in the above configuration, the total number of atoms of element M present in multiple materials is multiplied by the number of multiple materials. Preferably, the number of magnesium atoms in the raw material is 0.005 or more and 0.05 or less. .

[0020] Furthermore, in the above configuration, the total number of atoms of element M present in multiple materials is multiplied by the number of multiple materials. The number of fluorine atoms in the raw material is preferably 0.01 or more and 0.1 or less.

[0021] Furthermore, in the above configuration, one of the multiple raw materials is a compound having element M, and multiple raw materials One of the other is a compound containing lithium, and one of the multiple raw materials contains magnesium. It is preferable that it be a compound.

[0022] Furthermore, in the above configuration, the thickness of the second region is 0.5 nm or more and 50 nm or less. It is preferable. [Effects of the Invention]

[0023] According to one aspect of the present invention, by using it in a lithium-ion secondary battery, the charge-discharge cycle This provides a positive electrode active material that suppresses the decrease in capacity. Furthermore, it can provide a high-capacity secondary electrode We can provide a pond. We can also provide a secondary battery with excellent charge / discharge characteristics. Furthermore, it is possible to provide safe or highly reliable secondary batteries. Also, novel materials, We can provide active material particles, energy storage devices, or methods for producing them. [Brief explanation of the drawing]

[0024] [Figure 1] A diagram illustrating an example of positive electrode active material particles. [Figure 2] A diagram illustrating an example of a method for producing positive electrode active material particles. [Figure 3] Cross-sectional view of the active material layer when a graphene compound is used as a conductive additive. [Figure 4] A diagram illustrating a coin-type rechargeable battery. [Figure 5] A diagram illustrating a cylindrical rechargeable battery. [Figure 6] A diagram illustrating an example of an energy storage device. [Figure 7] A diagram illustrating an example of an energy storage device. [Figure 8] A diagram illustrating an example of an energy storage device. [Figure 9] A diagram illustrating an example of an energy storage device. [Figure 10] A diagram illustrating an example of an energy storage device. [Figure 11] A diagram illustrating a laminated rechargeable battery. [Figure 12] A diagram illustrating a laminated rechargeable battery. [Figure 13] A diagram showing the external appearance of a secondary battery. [Figure 14] A diagram showing the external appearance of a secondary battery. [Figure 15] A diagram illustrating the method for manufacturing a secondary battery. [Figure 16] A diagram illustrating a rechargeable battery that can be bent. [Figure 17] A diagram illustrating a rechargeable battery that can be bent. [Figure 18] A diagram illustrating an example of an electronic device. [Figure 19] A diagram illustrating an example of an electronic device. [Figure 20] A diagram illustrating an example of an electronic device. [Figure 21] A diagram illustrating an example of an electronic device. [Figure 22] SEM observation results. [Figure 23] SEM observation results. [Figure 24] SEM observation results. [Figure 25] Particle size distribution measurement results. [Figure 26] Particle size distribution measurement results. [Figure 27] XPS measurement results. [Figure 28] XPS measurement results. [Figure 29] XPS measurement results. [Figure 30] Figure showing HAADF-STEM images. [Figure 31] A diagram showing the energy density maintenance rate of a secondary battery. [Modes for carrying out the invention]

[0025] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention This is not limited to the description below, and its form and details can be changed in various ways, as is the case for those skilled in the art. This will be easily understood. Furthermore, the present invention shall be interpreted as being limited to the contents of the embodiments described below. It is not something that should be done.

[0026] Furthermore, in crystallography, crystal planes and directions are indicated by superscripts above the numbers, but in this specification... In the notation of crystal planes and directions in such documents, due to the constraints of patent application notation, a bar is placed above the number instead of... This is expressed by adding a minus sign (-) before the number. Additionally, individual directions within the crystal are indicated. The position is [ ], the collective orientation showing all equivalent directions is < >, and the individual planes showing crystal planes are ( In this system, sets of surfaces with equivalent symmetry are represented by {} respectively.

[0027] In this specification, segregation refers to the process of segregation in a solid composed of multiple elements (for example, A, B, C). This refers to the phenomenon where a certain element (for example, B) is distributed unevenly.

[0028] In this specification, etc., layered rock salt-type crystals of composite oxides containing lithium and transition metals The structure has a rock salt-type ionic arrangement in which cations and anions are arranged alternately, and transition metals Because lithium is arranged in a regular pattern to form a two-dimensional plane, two-dimensional diffusion of lithium is possible. This refers to a crystal structure. It may also contain vacancies in cations or anions.

[0029] In this specification, the similarity in the structure of a two-dimensional interface is referred to as epitaxy. Furthermore, crystal growth that has similarities to the structure of a two-dimensional interface is called epitaxial growth. Topotaki refers to having dimensional structural similarities or having the same crystallographic orientation. It is called topotaxy. Therefore, if it is topotaxy, when you observe a part of the cross-section, you will see two regions (for example For example, the orientation of the crystals in the underlying region and the region formed by growth coincide.

[0030] A rock salt crystal structure is a structure in which cations and anions are arranged alternately. Deficiencies in ions or anions are acceptable.

[0031] Layered rock salt crystals and the anions of rock salt crystals have a cubic close-packed structure (face-centered cubic lattice structure). When layered rock salt crystals and rock salt crystals are in contact, cubic close-packed beds of anions are formed. There are crystal planes with matching packing structures. However, the space group of layered rock salt crystals is R-3. Since it is m, and is different from the space group Fm-3m of rock salt crystals, the crystal planes that satisfy the above conditions The index differs between layered rock salt crystals and rock salt crystals. In this specification, layered rock salt crystals and rock salt In a type crystal, when the directions of crystal planes that satisfy the above conditions coincide with each other, the orientation of the crystals coincides. It is possible to say that.

[0032] For example, lithium cobalt oxide having a layered rock salt-type crystal structure and When magnesium oxide comes into contact with lithium cobalt oxide, the crystal orientations coincide. When the (1-1-4) surface and the {001} surface of magnesium oxide are in contact, lithium cobalt oxide When the (104) surface of the lithium cobalt oxide is in contact with the {001} surface of the magnesium oxide, When the (0-14) plane and the {001} plane of magnesium oxide are in contact, lithium cobalt oxide When the (001) surface and the {111} surface of magnesium oxide are in contact, lithium cobalt oxide ( This includes cases where the {111} surface of magnesium oxide is in contact with the {012} surface.

[0033] The coincidence of crystal orientation in the two regions is evident in TEM (transmission electron microscope) images, STEM ( Scanning transmission electron microscope (STEM) image, HAADF-STEM (High-angle scattering annular dark-field scanning transmission electron microscope) image This can be determined from mirror images, ABF-STEM (annular bright-field scanning transmission electron microscope) images, etc. X-ray diffraction (XRD), electron diffraction, neutron Linear diffraction and other methods can also be used as criteria for judgment. If the crystal orientations match, TEM images, etc. More preferably, the difference in direction between the rows in which cations and anions are arranged alternately in a straight line is 5 degrees or less. It can be observed that the temperature is below 2.5 degrees. Furthermore, TEM images show oxygen, fluorine, and other elements. In some cases, the light elements may not be clearly observable, but in such cases, the orientation matches in the arrangement of the metallic elements. It is possible to make that determination.

[0034] Space groups are used, for example, in X-ray diffraction, electron diffraction, STEM images, and FFT (fast transform) of TEM images. Structure can be analyzed and determined from methods such as the -lie transform. For example, FFT of a STEM image. The image was analyzed, and ICDD (International Centre for Diff) The crystal structure is identified by cross-referencing it with databases such as the (Raction Data) database. do.

[0035] (Embodiment 1) In this embodiment, a positive electrode active material particle, which is one aspect of the present invention, will be described.

[0036] [Structure of the positive electrode active material] First, using Figure 1, we will describe a positive electrode active material particle 100, which is one embodiment of the present invention. As shown in 1(A), the positive electrode active material particle 100 has a first region 101 and a first region 10 It has a second region 102 that is in contact with the outside of 1. The second region 102 is the first region 101 It could be said that it covers at least a portion of it.

[0037] The second region 102 is preferably a layered region.

[0038] The first region 101 and the second region 102 are regions having different compositions from each other. The boundary between the two regions may not be clear. In Figure 1(A), the first region 101 and the second region The region 102 is divided by a dotted line, and the concentration gradient of elements that cross the dotted line is shown in gray. The boundary between the first region 101 and the second region 102 is shown in shades of gray. For convenience, the boundary between the first region 101 and the second region 102 is shown in Figure 1(B) and subsequent figures. This will be shown only by a dotted line. Details of the boundary between the first region 101 and the second region 102 This will be explained later.

[0039] Furthermore, as shown in Figure 1(B), a second region 102 exists inside the positive electrode active material particle 100. This may also be done. For example, when the first region 101 is polycrystalline, the second region 102 is at the grain boundary. Segregation is acceptable. Also, a second region is formed in the part of the positive electrode active material particle 100 that has crystal defects. 102 may be segregated. In this specification, crystal defects are observed by TEM. This refers to possible body defects, or structures in which other elements are incorporated into the crystal.

[0040] Furthermore, the second region 102 does not have to cover the entirety of the first region 101.

[0041] In other words, the first region 101 is located inside the positive electrode active material particle 100, and the second region Region 102 is located on the surface of the positive electrode active material particle 100. Furthermore, the second region 102 is positive It may be present inside the highly active material particles 100.

[0042] The first region 101 may also be called, for example, solid phase A. The second region 102 is In other words, it could be called solid phase B.

[0043] <First Domain 101> The first region 101 contains lithium, element M, and oxygen. Element M is a plurality of elements. This may also be the case. Element M is one or more elements selected from, for example, transition metals. For example, Region 101 of 1 has a composite oxide containing lithium and a transition metal.

[0044] As element M, a transition metal capable of forming a layered rock salt-type composite oxide with lithium is used. It is preferable to have one or more of the following: manganese, cobalt, and nickel. It can be used. In other words, only cobalt can be used as the transition metal in the first region 101. You may use one type, or you may use two types, cobalt and manganese, or cobalt, manganese, nickel The three types of Kell may also be used. Furthermore, for example, in addition to transition metals, aluminum may be used as element M. Other metals besides transition metals may also be used.

[0045] In other words, the first region 101 is composed of lithium cobaltate, lithium nickelate, and cobalt. Lithium cobaltate with manganese substitution, nickel-manganese-cobaltate lithium Composites containing lithium and transition metals, such as lithium nickel-cobalt-aluminate. It may contain oxides.

[0046] In the layered rock salt crystal structure, lithium diffuses easily in two dimensions, so the first region 101 and It is preferable to do so. Also, if the first region 101 has a layered rock salt type crystal structure, surprisingly As described later, segregation of magnesium oxide is likely to occur. However, all of the first region 101 It does not have to be a layered rock salt type crystal structure. For example, if there are crystal defects in a part of the first region 101 Alternatively, part of the first region 101 may be amorphous, or other crystalline structures may be... It is acceptable to have it.

[0047] The first region 101 can sometimes be represented by the space group R-3m.

[0048] <Second Domain 102> The second region contains element M and oxygen. For example, the second region contains an oxide of element M. To possess.

[0049] Furthermore, the second region preferably contains magnesium in addition to elements M and oxygen. Furthermore, it is preferable that the second region contains fluorine. Having this feature may improve the stability of charging and discharging the secondary battery, which is preferable. Here, high stability of a secondary battery means, for example, that the change in the crystal structure of the positive electrode active material particles 100 is minimal. It refers to being suppressed. Or, it refers to a small change in capacity. Or, the second territory This refers to the suppression of valence state changes of transition metals, such as cobalt, present in region 102.

[0050] The second region 102 has, for example, magnesium oxide, and some of the oxygen is replaced by fluorine. It is fine. Magnesium oxide is a chemically stable material, so even if it is repeatedly charged and discharged... It is less prone to deterioration and is suitable as a coating layer.

[0051] By partially substituting magnesium oxide with fluorine, for example, lithium Dispersibility can be increased and charging and discharging are not hindered. Also, the surface layer of the positive electrode active material, for example, the second The presence of fluorine near region 102 can make it difficult to dissolve in hydrofluoric acid.

[0052] The second region 102, if too thin, will have reduced functionality as a coating layer, but if too thick... This leads to a decrease in capacity. Therefore, the thickness of the second region 102 should be between 0.5 nm and 50 nm. Preferably, the wavelength is 0.5 nm or more and more preferably 3 nm or less.

[0053] The thickness of the second region 102 can be measured by TEM. For example, cathode active material particles. After processing and exposing the cross-section, observation can be performed using a TEM.

[0054] If the second region 102 has a rock salt-type crystal structure, then the crystal orientation is different from that of the first region 101. It is preferable because it is easy to match and functions as a stable coating layer. However, the second region 1 Not all of 02 has to be a rock salt type crystal structure. For example, part of the second region 102 is non It may be crystalline or have other crystalline structures.

[0055] The second region 102 can sometimes be represented by the space group Fm-3m.

[0056] Generally, as the positive electrode active material particles 100 undergo repeated charging and discharging, cobalt, manganese, etc. Side effects include the dissolution of transition metals into the electrolyte, the release of oxygen, and the instability of the crystal structure. A reaction occurs, and degradation progresses. However, the positive electrode active material particles 100 in one aspect of the present invention Because it has a second region 102 on the surface, the lithium and transition gold in the first region 101 It is possible to make the crystal structure of complex oxides containing this group more stable.

[0057] The number of lithium atoms relative to element M in the process for producing a positive electrode active material according to one aspect of the present invention. The relationship between the ratio and the second region that is formed will be explained. In the fabrication process, excess Element M is abundantly distributed on the surface, forming a second region. Atomic ratio of lithium to element M. By reducing (hereinafter referred to as Li / M), excess element M is generated, forming a second region. It is possible.

[0058] In the second region, the ratio of element M to lithium is higher compared to the first region. (That is, Li / M is small). Alternatively, in the second region, lithium is not detected. There are cases where this is the case.

[0059] On the other hand, increasing the Li / M ratio increases the average particle size of the positive electrode active material particles 100. This can occur. As the average particle size increases, the specific surface area decreases. Secondary batteries Let's consider the case where side reactions such as the decomposition of the electrolyte occur. In such cases, the active material particles Reducing the specific surface area decreases the area in contact with the electrolyte, thereby reducing the amount of side reactions. This is possible. Here, a side reaction refers, for example, to an irreversible reaction during the charging and discharging of a secondary battery. .

[0060] Furthermore, as shown in Figure 1(B), a second region 102 exists inside the first region 101. Furthermore, the crystal structure of the lithium and transition metal composite oxide in the first region 101 is further It is preferable that it can be stabilized.

[0061] Furthermore, the fluorine present in the second region 102 is in a bonding state other than MgF2, LiF, and CoF2. It is preferable that the surface of the positive electrode active material particles 100 is XPS(X When analyzed by photoelectron spectroscopy, the peak position of the fluorine bond energy was 682 eV. It is preferable that the voltage is 685 eV or less, and more preferably around 684.3 eV. This is a bond energy that does not match that of either MgF2 or LiF.

[0062] In this specification, the peak position of the bond energy of a certain element when analyzed by XPS is used. An "energy field" is the range in which the intensity of the energy spectrum corresponds to the bonding energy of that element. This refers to the value of the bond energy that is greatest.

[0063] <First area 101 and second area 102> The first region 101 and the second region 102 are TEM images, STEM images, and FFT (Fast Fourier Scale). (E-conversion) analysis, EDX (Energy Dispersive X-ray Analysis), ToF-SIMS (Time-of-Flight 2-bit X-ray Spectroscopy) Depth analysis by ion mass spectrometry, XPS, Auger electron spectroscopy, TDS (transitional ion mass spectrometry), Different compositions can be confirmed by methods such as thermal desorption gas analysis. For example, TEM images. Furthermore, in STEM images, differences in constituent elements are observed as differences in image brightness, therefore, It can be observed that the constituent elements of region 101 and region 202 are different. Also, EDX In the elemental distribution image, it was observed that the first region 101 and the second region 102 contained different elements. Yes. However, various analyses do not necessarily provide a clear distinction between the first area 101 and the second area 102. It is not necessary for the boundary to be observable.

[0064] The concentrations of lithium, element M, magnesium, and fluorine were determined by ToF-SIMS, XPS, Analysis can be performed using Auger electron spectroscopy, TDS, etc.

[0065] XPS can quantitatively analyze an area of ​​approximately 5 nm from the surface of 100 cathode active material particles. Therefore, if the thickness of the second region 102 is less than 5 nm, the second region 102 and the first region If the thickness of the second region 102, which is a combination of a part of region 101, is 5 nm or more from the surface, The elemental concentrations in the second region 102 can be quantitatively analyzed.

[0066] For example, the Li / M ratio measured using XPS in the positive electrode active material particles 100 is 0.5 or higher. It is 0.85 or less.

[0067] Furthermore, the magnesium for element M measured using XPS in the positive electrode active material particles 100 The atomic ratio of um (hereinafter referred to as Mg / M) is preferably greater than 0.15, and 0.2 Preferably, it is 0.5 or less, and preferably 0.3 or more and 0.4 or less.

[0068] Furthermore, the fluorine content relative to element M, measured using XPS in the positive electrode active material particles 100, The atomic ratio (hereinafter referred to as F / M) is preferably 0.02 or more and 0.15 or less.

[0069] The crystal structures of the first region 101 and the second region 102 can be determined, for example, by electron diffraction patterns, or T This can be evaluated by analyzing the fast inverse Fourier transform image of the EM image.

[0070] <Third Domain 103> Previously, the positive electrode active material particles 100 had a first region 101 and a second region 102. While examples have been described, the present invention is not limited to these. For example, as shown in Figure 1(C) Thus, the positive electrode active material particles 100 may have a third region 103. 3 can, for example, be provided so as to be in contact with at least a portion of the second region 102. The third region 103 may be a carbon-containing coating, including a graphene compound. The coating may have decomposition products of lithium or the electrolyte. Third region 10 If 3 is a coating containing carbon, then positive electrode active material particles 100 and positive electrode active material particles 1 The conductivity between 00 and the current collector can be increased. Also, the third region 103 is lithium or In the case of a coating containing decomposition products of the electrolyte, excessive reaction with the electrolyte is suppressed, and secondary batteries When used in this way, it can improve cycle characteristics.

[0071] [Manufacturing method] It has a first region 101 and a second region 102, and the second region 102 is shaped by segregation. The method for producing the positive electrode active material particles 100 in this case will be explained using Figure 2.

[0072] First, prepare the starting materials (S11). Specifically, lithium source, element M source, magnesium Weigh the um source and fluorine source separately. For example, lithium carbonate can be used as the lithium source. Lithium fluoride, lithium hydroxide, etc. can be used. When element M is cobalt... For example, cobalt sources include cobalt oxide, cobalt hydroxide, cobalt oxyhydroxide, and carbonic acid. Cobalt, cobalt oxalate, cobalt sulfate, etc., can be used. Magnesium is also available. For example, magnesium oxide, magnesium fluoride, etc., can be used as a source. Furthermore, lithium fluoride, magnesium fluoride, etc., can be used as fluorine sources. Yes, it is possible. In other words, lithium fluoride can be used as both a lithium source and a fluorine source. Furthermore, magnesium fluoride can be used as both a magnesium source and a fluorine source. Cut.

[0073] In this embodiment, lithium carbonate (Li2CO3) is used as the lithium source and the cobalt source is used. Cobalt oxide (Co3O4), magnesium oxide (MgO) as a magnesium source, Lithium fluoride (LiF) will be used as the thium source and fluorine source.

[0074] In one embodiment of the present invention, a magnesium source and a fluorine source are mixed simultaneously as starting materials. By doing so, the second region 102 having magnesium and fluorine is formed by the positive electrode active material particles 10 It was possible to form it on the surface layer of 0.

[0075] Here, the total number of lithium atoms in the starting material is divided by the total number of atoms of element M. Let the value be (Li / M)_R.

[0076] Next, the weighed starting materials are mixed (S12). For mixing, a ball mill or bead mill can be used. You can use things like Lu.

[0077] Next, the mixture from S12 is subjected to a first heating (S13). The first heating is performed at 800°C or higher. It is preferable to perform the process at a temperature of 1050°C or lower, and more preferably at a temperature of 900°C to 1000°C. Preferably, the heating time should be between 2 hours and 20 hours. It is preferable to perform the heat treatment in an open atmosphere. In this embodiment, the heat treatment is performed at 1000°C for 10 hours. The heating process will be carried out at a rate of 200°C / h, with a dry air flow rate of 10 L / min.

[0078] The first heating in S13 forms the first region 101. Here, (Li / M)_R By reducing this, element M becomes surplus. Due to the surplus element M, the first region 101 A layer mainly composed of excess element M is more likely to form outside of it. For example, the first region 10 The Li / M ratio of the entire positive electrode active material particle 100 is reduced compared to the Li / M ratio of the composite oxide in 1. By making element M a surplus, the element is placed outside the first region 101. A second region 102 having M and oxygen is formed.

[0079] Furthermore, some of the lithium is released outside the system (outside the particles being produced) by the first heating in S13. In some cases, this occurs. That is, some of the lithium is lost. Therefore, (Li / M)_R(raw material) Compared to the ratio of lithium to element M in the S16 process, the overall composition of the positive electrode active material particles after passing through S16 In some cases, the Li / M ratio may become smaller.

[0080] The formation of the first region 101 and the second region 102 will be described in more detail below. ru.

[0081] For example, if element M is cobalt and the first region 101 contains lithium cobalt oxide Let's consider this. The Li / M ratio of lithium cobalt oxide is close to 1. The L ratio of the entire positive electrode active material particles is... By making i / M less than 1, elements M and oxygen are placed outside the first region 101. A second region 102 is formed.

[0082] Considering that some lithium is lost, (Li / M)_R should be less than, for example, 1.05. By doing so, a second region 102 containing cobalt is formed outside the first region 101. It will be done.

[0083] Furthermore, increasing (Li / M)_R reduces the specific surface area of ​​the positive electrode active material particles. It can happen.

[0084] The second region 102 is preferably stable even during the charging and discharging process of the secondary battery. Metals other than transition metals, such as magnesium, do not change their valency, so their compounds undergo transition. Compared to metal compounds, in secondary batteries that use oxidation-reduction reactions such as lithium-ion batteries, It can be said to be more stable. The presence of magnesium in the second region 102 makes the positive electrode active Side reactions on the surface of material particle 100 are suppressed. Therefore, the second region 102 is magnesium It is preferable that it contains um.

[0085] However, according to the inventors' experiments, (Li / M)_R (where element M is cobalt) As it increases, that is, as the atomic ratio of cobalt to the total raw materials decreases, the second In some cases, region 102 would become thinner, or the second region 102 would be difficult to form.

[0086] Furthermore, if the second region 102 is difficult to form, the magnesium concentration of the first region 101 The degree may increase. Magnesium present in the first region 101 inhibits charging and discharging. There are cases where this can occur. For example, it can reduce discharge capacity or degrade cycle characteristics. ru.

[0087] The inventors created a cobalt acid by making cobalt an excess, which is the first region 101. A region containing lithium is formed, and a region with a cobalt framework is formed as the second region 102. After or simultaneously with the formation, magnesium is segregated into the second region 102. As a result, a second region 102 having magnesium and a rock salt-type structure is formed. I discovered that...

[0088] Magnesium and fluorine, upon first heating in S13, partially transfer to the second region 102. Segregation occurs. For example, magnesium is substituted for cobalt and a portion of it in the second region 102. This may also be done. Furthermore, fluorine may be replaced, for example, by the oxygen and a portion thereof in the second region 102. It may be done. However, at this point, the magnesium and other parts of fluorine will transition with lithium. It is in a state of solid solution within a complex oxide containing metal.

[0089] Furthermore, by adding fluorine to the positive electrode active material according to one aspect of the present invention, the second region 102 In some cases, magnesium may be more prone to segregation.

[0090] The oxygen that binds to magnesium is replaced by fluorine, and the area around the substituted fluorine... In some cases, magnesium may become more mobile.

[0091] Furthermore, adding magnesium fluoride to magnesium oxide can sometimes lower its melting point. Lowering the melting point makes it easier for atoms to move during heat treatment.

[0092] Furthermore, fluorine has a higher electronegativity than oxygen. Therefore, like magnesium oxide... Even in stable compounds, the addition of fluorine causes an imbalance in charge, and magnesium This can sometimes weaken the bond with oxygen.

[0093] For these reasons, by adding fluorine to the positive electrode active material of one aspect of the present invention, In some cases, magnesium becomes more mobile, and magnesium is more likely to segregate in the second region. ru.

[0094] Next, the material heated in S13 is cooled to room temperature (S14).

[0095] Next, the material cooled in S14 is subjected to a second heating (S15). The second heating is performed at a specified temperature. It is preferable to perform the holding time for 50 hours or less, and to perform it for 2 hours or more and 10 hours or less. More preferable. The specified temperature is preferably 500°C to 1200°C, and 700°C or higher. A temperature of 1000°C or less is more preferable, and around 800°C is even more preferable. Also, an atmosphere containing oxygen is preferable. Heating by air is preferable. In this embodiment, heating is performed at 800°C for 2 hours. The heating rate will be 200°C / h, and the dry air flow rate will be 10 L / min.

[0096] By performing the second heating in S15, the magnesium and fluorine contained in the starting material are converted into lithium Segregation of composite oxides containing um and transition metals to the surface layer is promoted, and the second region 102 of Magnesium is promoted. It is possible to increase the concentrations of nesium and fluorine.

[0097] Finally, the material heated in S15 is cooled to room temperature and collected (S16) to form positive electrode active material particles. You can obtain 100 offspring.

[0098] By using the positive electrode active material particles described in this embodiment, high capacity and good cycle characteristics can be achieved. This can be used as a secondary battery. This embodiment can be used in appropriate combination with other embodiments. It is possible to be there.

[0099] (Embodiment 2) In this embodiment, a secondary battery having the positive electrode active material particles 100 described in the previous embodiment. Examples of materials that can be used will be described. In this embodiment, the positive electrode, the negative electrode and Let's take a secondary battery, in which the electrolyte is enclosed in an outer casing, as an example.

[0100] [Positive electrode] The positive electrode comprises a positive electrode active material layer and a positive electrode current collector.

[0101] <Cathode active material layer> The positive electrode active material layer has positive electrode active material particles. Furthermore, the positive electrode active material layer contains conductive additives and It may have an industrial component.

[0102] As the positive electrode active material particles, the positive electrode active material particles 100 described in the previous embodiment are used. This is possible. By using the positive electrode active material particles 100 described in the previous embodiment, high capacity is possible. This allows for the creation of a secondary battery with excellent cycle characteristics.

[0103] As a conductive additive, carbon materials, metal materials, or conductive ceramic materials can be used. This is possible. In addition, fibrous materials may be used as conductive additives. The content of the conductive additive is preferably 1 wt% to 10 wt%, and preferably 1 wt% to 5 wt%. The bottom one is preferable.

[0104] Conductive additives can be used to form an electrical conduction network within the active material layer. The auxiliary agent can maintain the electrical conduction pathways between the positive electrode active materials. By adding a conductive additive, it is possible to realize an active material layer with high electrical conductivity. ru.

[0105] Examples of conductive additives include natural graphite, artificial graphite such as mesocarbon microbeads, and carbon. Fibers can be used. For example, mesophase pitch carbon fibers can be used. Carbon fibers such as fiber and isotropic pitch carbon fibers can be used. Carbon nanofibers and carbon nanotubes can be used. Notubes can be fabricated, for example, by vapor phase growth. Also, as a conductive additive, For example, carbon black (acetylene black (AB), etc.), graphite particles. Carbon materials such as ions, graphene, and fullerenes can be used. Also, for example, copper, Metal powders and fibers such as nickel, aluminum, silver, and gold, and conductive ceramic materials, etc. You can use it.

[0106] Furthermore, graphene compounds may be used as conductive additives.

[0107] Graphene compounds possess excellent electrical properties, including high conductivity, and high flexibility. It may possess excellent physical properties such as high mechanical strength. The compound has a planar shape. The graphene compound enables surface contact with low contact resistance. Furthermore, even thin materials can have very high conductivity, allowing for efficient use within the active material layer in small quantities. A conductive path can be formed. Therefore, graphene compounds are used as conductive additives. This is preferable because it increases the contact area between the active material and the conductive additive. Furthermore, it is preferable because it can reduce electrical resistance. Here, as a graphene compound For example, graphene or multigraphene or reduced graphene It is particularly preferable to use an oxide (hereinafter referred to as RGO). Here, RGO is, for example, an acid. This refers to compounds obtained by reducing graphene oxide (GO). .

[0108] When using active material particles with small particle sizes, for example, active material particles of 1 μm or less, The specific surface area of ​​this material is large, and therefore more conductive paths are needed to connect the active material particles. In such cases, graphene compounds that can efficiently form conductive paths even in small quantities are used. It is particularly preferable to use it.

[0109] In the following example, a graphene compound is used as a conductive additive in the active material layer 200. An example of a cross-sectional configuration of the joint will be explained.

[0110] Figure 3(A) shows a longitudinal cross-sectional view of the active material layer 200. The active material layer 200 consists of granular positive electrode active materials. A solid particle 100, a graphene compound 201 as a conductive additive, and a binder (not shown) , including. Here, graphene compound 201 is, for example, graphene or multigraph. You can use graphene. Here, graphene compound 201 has a sheet-like shape. Preferred. Also, graphene compound 201 is a multiple multigraphene, or (and Multiple layers of graphene may partially overlap to form a sheet.

[0111] In the longitudinal section of the active material layer 200, as shown in Figure 3(A), the interior of the active material layer 200 In Figure 3(A), the graphene compound 201 is dispersed in a generally uniform sheet-like manner. The graphene compound 201 is schematically represented by a thick line, but in reality it is a single layer of carbon molecules or It is a thin film with multiple layers and thickness. Multiple graphene compounds 201 are multiple granular cathode active The material particle 100 is surrounded, covered, or surrounded by multiple granular positive electrode active material particles 100 Because they are formed to adhere to the surface, they are in surface contact with each other.

[0112] Here, multiple graphene compounds bond together to form a network of graphene compounds. Forming a material sheet (hereinafter referred to as graphene compound net or graphene net) This is possible. When the active material is covered with a graphene net, the graphene net interacts with the active material. It can also function as a binder to combine them. Therefore, the amount of binder can be reduced. Because it is possible or not to use the active material in relation to the electrode volume and electrode weight The ratio can be improved. In other words, the capacity of the energy storage device can be increased.

[0113] Here, graphene oxide is used as graphene compound 201 and mixed with the active material to produce the active material It is preferable to form a layer that will become the 200th layer and then reduce it. Formation of graphene compound 201 Furthermore, by using graphene oxide, which has extremely high dispersibility in polar solvents, graphene Compound 201 can be dispersed approximately uniformly within the active material layer 200. The solvent is volatilized and removed from the dispersion medium containing dispersed graphene oxide, and the graphene oxide is returned. Therefore, the graphene compound 201 remaining in the active material layer 200 partially overlaps, By being dispersed to the extent that they are in surface contact with each other, a three-dimensional conductive path can be formed. Furthermore, the reduction of graphene oxide may be carried out, for example, by heat treatment, or by using a reducing agent. You may go.

[0114] Therefore, unlike granular conductive additives such as acetylene black that make point contact with the active material, the graph Since compound 201 enables surface contact with low contact resistance, it is not a typical conductive additive. Using a smaller amount, the electrical conductivity between granular positive electrode active material particles 100 and graphene compound 201 is improved. This can be increased. Therefore, the ratio of positive electrode active material particles 100 in the active material layer 200 can be increased. It can be increased. This allows for an increase in the discharge capacity of the energy storage device.

[0115] Examples of binders include styrene-butadiene rubber (SBR) and styrene-isopropyl alcohol. Lenyl-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, ethylene- It is preferable to use a rubber material such as a propylene-diene copolymer as a binder. Therefore, fluororubber can be used.

[0116] Furthermore, it is preferable to use a water-soluble polymer as the binder. As molecules, for example, polysaccharides can be used. As for polysaccharides, carboxymethyl Cholecellulose (CMC), methylcellulose, ethylcellulose, hydroxypropyl Cellulose derivatives such as cellulose, diacetylcellulose, and regenerated cellulose, and starch These can be used. In addition, these water-soluble polymers can be used in combination with the aforementioned rubber material. It is even preferable if used.

[0117] Alternatively, the binder could be polystyrene, methyl polyacrylate, or polymethacrylic acid. Methyl (polymethyl methacrylate (PMMA)), sodium polyacrylate, polyvinyl Nyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide Polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene Pyrene, polyisobutylene, polyethylene terephthalate, nylon, polyvinyl fluoride Den (PVDF), polyacrylonitrile (PAN), ethylene propylene diem polymer - It is preferable to use materials such as polyvinyl acetate and nitrocellulose.

[0118] You may use a combination of several of the binders mentioned above.

[0119] For example, a material with particularly excellent viscosity-modifying properties may be used in combination with other materials. For example, rubber materials have excellent adhesive and elastic properties, but when mixed with a solvent, it is difficult to adjust their viscosity. In such cases, for example, mixing with a material that has particularly excellent viscosity-modifying effects may be necessary. This is preferable. As a material with particularly excellent viscosity adjustment effect, for example, a water-soluble polymer can be used. Good. Also, as water-soluble polymers that are particularly excellent in viscosity adjustment, the aforementioned polysaccharides, for example, Boxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydrox Cellulose inducers such as cypropylcellulose, diacetylcellulose, and regenerated cellulose Conductors and starch can be used.

[0120] Furthermore, cellulose derivatives such as carboxymethylcellulose are, for example, carboxymethyl Solubility increases when cellulose is converted into salts such as sodium salts or ammonium salts. This makes it easier for the viscosity modifier to exert its effect. The increased solubility makes it easier for the electrode slurry to When preparing the Lee, it is also possible to improve the dispersibility of the active material and other components. In this case, the cellulose and cellulose derivatives used as electrode binders are: These salts shall also be included.

[0121] Water-soluble polymers stabilize viscosity by dissolving in water, and also act as active materials and binders. Other materials to be combined with them, such as styrene-butadiene rubber, are stable in aqueous solution. It can be dispersed. Furthermore, because it has functional groups, it is easily and stably adsorbed onto the surface of the active material. It is expected that this will happen. Also, cellulose derivatives such as carboxymethylcellulose are For example, many materials have functional groups such as hydroxyl groups and carboxyl groups, and because they have functional groups It is expected that the polymers will interact with each other and exist to broadly cover the surface of the active material.

[0122] When a binder covering or in contact with the surface of the active material forms a film, a passivation film and It is also expected to play a role in suppressing the decomposition of the electrolyte. Here, the passive membrane is, A film that does not conduct electricity, or has extremely low electrical conductivity, for example, on the surface of an active material. When a passivation film is formed, it suppresses the decomposition of the electrolyte at the battery reaction potential. Yes, it is possible. Furthermore, the passivation film suppresses electrical conductivity, while lithium ions can conduct electricity. That would be even better.

[0123] <Positive electrode current collector> As the positive electrode current collector, metals such as stainless steel, gold, platinum, aluminum, and titanium, and Highly conductive materials such as these alloys can be used. Also, materials used for the positive electrode current collector It is preferable that the material does not dissolve at the positive electrode potential. Also, silicon, titanium, neodymium, and Aluminum alloys to which elements that improve heat resistance, such as candium and molybdenum, have been added. It can be used. Furthermore, it can be formed with a metallic element that reacts with silicon to form a silicide. It may also be the case that, as a metallic element that reacts with silicon to form a silicide, zirconium, Titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten Examples include cellulose, cobalt, and nickel. Current collectors come in foil, plate (sheet), mesh, and perforated forms. Shapes such as metal-like or expanded metal-like can be used as appropriate. The current collector has a thickness It is best to use particles that are between 5 μm and 30 μm in size.

[0124] [Negative electrode] The negative electrode has a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer also contains a conductive additive. It may have a binder.

[0125] <Negative electrode active material> For example, alloy materials or carbon-based materials can be used as the negative electrode active material.

[0126] As a negative electrode active material, the charge-discharge reaction is carried out by alloying and dealloying reactions with lithium. Any possible element can be used. For example, silicon, tin, gallium, aluminum, Germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. Materials containing at least one of these elements can be used. Such elements have a capacity compared to carbon. Larger, and especially silicon, has a high theoretical capacity of 4200 mAh / g. Therefore, the negative electrode active material Silicon is preferred. Compounds containing these elements may also be used. For example, SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag 3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, Examples include InSb and SbSn. Here, charging and discharging occur through alloying and dealloying reactions with lithium. In some cases, elements capable of carrying out reactions, and compounds containing such elements, are referred to as alloying materials. be.

[0127] In this specification, SiO refers to silicon monoxide, for example. Alternatively, SiO refers to Si O x It can also be expressed as follows. Here, it is preferable that x has one neighboring value. For example, x is A value of 0.2 to 1.5 is preferred, and 0.3 to 1.2 is preferred.

[0128] Examples of carbon-based materials include graphite, easily graphitizable carbon (soft carbon), and poorly graphitizable carbon (hard carbon). Using carbon fiber, carbon nanotubes, graphene, carbon black, etc. stomach.

[0129] Examples of graphite include artificial graphite and natural graphite. For example, meso Examples include carbon microbeads (MCMB), coke-based artificial graphite, pitch-based artificial graphite, etc. Here, as the artificial graphite, spherical graphite having a spherical shape can be used. For example, MCMB may have a spherical shape, which is preferable. Also, it is relatively easy to reduce the surface area of MCMB, which may be preferable. Examples of natural graphite include flake graphite, spheroidized natural graphite, etc.

[0130] Graphite exhibits a potential as low as that of lithium metal when lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound) (0.05 V or more and 0.3 V or less vs. Li / + Li ). As a result, a lithium-ion secondary battery can exhibit a high operating voltage. Furthermore, graphite has advantages such as a relatively high capacity per unit volume, relatively small volume expansion, low cost, and high safety compared to

[0131] lithium metal, so it is preferable. Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5 ), tungsten oxide (WO2), molybdenum oxide (MoO2), etc. can be used.

[0132] Also, as the negative electrode active material, Li3N-type structure-containing Li 3-x M x N (M = Co, Ni, Cu), which is a complex nitride of lithium and a transition metal, can 2. be used. For example, Li 0.4 6Co 3) is shown and is preferable.

[0133] When using a complex nitride of lithium and a transition metal, since the negative electrode active material contains lithium ions , it is possible and preferable to combine with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. In addition, even when using a material containing lithium ions as the positive electrode active material , it is possible to use a complex nitride of lithium and a transition metal as the negative electrode active material by previously desorbing the lithium ions contained in the positive electrode active material.

[0134] In addition, a material in which a conversion reaction occurs can also be used as the negative electrode active material. For example , transition metal oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO) that do not form an alloy with lithium may be used as the negative electrode active material. As materials in which a conversion reaction occurs , further, oxides such as Fe2O3, CuO, Cu2O, RuO2, and Cr2O3 , sulfides such as CoS , NiS, and CuS, nitrides such as Zn3N2, Cu3N, and Ge 0.89 , 3N4, phosphides such as NiP2, FeP2, and CoP3, and fluorides such as FeF3 and BiF3 also occur.

[0135] As the conductive assistant and binder that the negative electrode active material layer can have, the same materials as the conductive assistant and binder that the positive electrode active material layer can have can be used.

[0136] [Negative electrode current collector] For the negative electrode current collector, the same materials as the positive electrode current collector can be used. In addition, it is preferable to use a material that does not alloy with carrier ions such as lithium for the negative electrode current collector.

[0137] [Electrolyte solution] An electrolyte solution contains a solvent and an electrolyte. A non-protic organic solvent is preferred as the solvent for the electrolyte solution. For example, ethylene carbonate (EC), propylene carbonate (PC), br Tylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyro Lactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate Tyl, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, 1,3-Dioxane, 1,4-Dioxane, Dimethoxyethane (DME), Dimethyl Sulfane Hoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetra One of the following, or two or more of these: trahydrofuran, sulfolane, sultone, etc. It can be used in combinations and ratios.

[0138] Furthermore, as the solvent for the electrolyte, an ionic liquid (a room-temperature molten salt) that is flame-retardant and non-volatile is used. By using one or more of these devices, the internal temperature of the energy storage device may rise due to internal short circuits or overcharging. However, this can prevent the rupture or ignition of the energy storage device. Ionic liquids are composed of cations and anions. It consists of and contains organic cations and anions. As organic cations used in the electrolyte, four quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations Aliphatic onium cations such as imidazolium cations and pyridinium cations, etc. Aromatic cations are an example. In addition, monovalent amides are used as anions in the electrolyte. Anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkyl Rusulfonic acid anion, tetrafluoroborate anion, perfluoroalkyl borate To anion, hexafluorophosphate anion, or perfluoroalkyl phosph Eto anion, etc. may be mentioned.

[0139] Also, as the electrolyte dissolved in the above solvent, for example, LiPF6, LiClO4, L iAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO 4, Li2B 10 Cl 10 、Li2B 12 Cl 12 、LiCF3SO3, LiC4F9S O3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN(CF3SO2 )2, LiN(C4F9SO2)(CF3SO2), LiN(C2F5SO2)2, etc. of lithium Salts can be used alone or in any combination and ratio of two or more of these. And can be.

[0140] The electrolyte used in the power storage device is preferably a highly purified electrolyte with a low content of particulate dust and elements other than the constituent elements of the electrolyte (hereinafter, simply referred to as " Impurities"). Specifically, the weight ratio of impurities to the electrolyte is preferably 1% or less, more preferably 0.1% or less, and even more Preferably 0.01% or less.

[0141] In addition, additives such as vinylene carbonate, propane sultone (PS), tert-butyl Benzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxa Late) borate (LiBOB), and dinitrile compounds such as succinonitrile and adiponitrile may be added. The concentration of the additive is, for example, 0. With respect to the entire solvent. It should be between 1 weight% and 5 weight%.

[0142] Alternatively, a polymer gel electrolyte, obtained by swelling a polymer with an electrolyte solution, may be used.

[0143] Using polymer gel electrolytes enhances safety against leakage and other issues. The pond can be made thinner and lighter.

[0144] Examples of polymers that can be gelled include silicone gel, acrylic gel, and acrylonitrile gel. Polyethylene oxide gel, polypropylene oxide gel, fluorine polymer Gels such as polyethylene oxide (PEO) can be used. Polymers having a chilenoxide structure, PVDF, and polyacrylonitrile, etc. Copolymers containing these can be used. For example, PVDF and hexafluoropolymers. PVDF-HFP, a copolymer of propylene (HFP), can be used. The resulting polymer may have a porous structure.

[0145] In addition, instead of an electrolyte, a solid electrolyte containing inorganic materials such as sulfide-based or oxide-based materials may be used. Solid electrolytes containing polymer materials such as polyethylene oxide (PEO) can be used. It is possible. When using a solid electrolyte, the installation of separators and spacers becomes unnecessary. Also, Because the entire battery can be made solid, the risk of leakage is eliminated, dramatically improving safety.

[0146] [Separator] Furthermore, it is preferable that the secondary battery has a separator. Examples of separators include: Paper and other cellulose-containing fibers, nonwoven fabrics, glass fibers, ceramics, or Nylon (polyamide), Vinylon (polyvinyl alcohol-based fiber), polyester, A This product uses synthetic fibers made from acrylic, polyolefin, polyurethane, etc. This can be done. The separator is processed into a bag shape and arranged to enclose either the positive or negative electrode. It is preferable to place it there.

[0147] The separator may have a multilayer structure. For example, polypropylene, polyethylene, etc. The equipment material film contains ceramic materials, fluorine-based materials, polyamide-based materials, or these materials. A mixture of these can be used as a coating. Examples of ceramic materials include, for example, oxidative materials. Aluminum particles, silicon oxide particles, etc. can be used. As for fluorine-based materials, For example, PVDF, polytetrafluoroethylene, etc. can be used. Polyamide Materials used include, for example, nylon and aramid (meta-aramid, para-aramid). It is possible to be there.

[0148] Coating with ceramic materials improves oxidation resistance, thus preventing separation during high-voltage charging and discharging. This can suppress the degradation of the data and improve the reliability of secondary batteries. Furthermore, fluorine-based materials... Coating the electrode makes it easier for the separator and electrode to adhere to each other, which can improve the output characteristics. Coating with polyamide materials, especially aramid, improves heat resistance, thus improving the performance of secondary batteries. Safety can be improved.

[0149] For example, a mixture of aluminum oxide and aramid material on both sides of a polypropylene film. It may also be coated. Furthermore, the surface of the polypropylene film in contact with the positive electrode may be coated with aluminum oxide. A mixture of um and aramid material may be coated, and a fluorine-based material may be coated on the surface in contact with the negative electrode. stomach.

[0150] Using a multilayer separator ensures the safety of secondary batteries even with a thin overall separator. Because this can be maintained, the capacity per unit volume of the secondary battery can be increased.

[0151] (Embodiment 3) In this embodiment, a secondary battery having the positive electrode active material particles 100 described in the previous embodiment. Let's describe an example of its shape. The material used in the secondary battery described in this embodiment is the same as the one described above. The description of the form of the application can be taken into consideration.

[0152] [Coin-type rechargeable battery] First, let's explain an example of a coin-type rechargeable battery. Figure 4(A) shows a coin-type (single-layer flattened type) Figure 4(B) is an external view of the secondary battery, and Figure 4(B) is a cross-sectional view thereof.

[0153] The coin-type rechargeable battery 300 consists of a positive electrode casing 301 which also serves as the positive electrode terminal and a negative electrode casing which also serves as the negative electrode terminal. The can 302 is insulated and sealed with a gasket 303 made of polypropylene or the like. The positive electrode 304 consists of a positive electrode current collector 305 and a positive electrode active material layer 30 provided in contact with it. It is formed by 6. The negative electrode 307 is provided with the negative electrode current collector 308 and is set to be in contact with it. It is formed by the kerned negative electrode active material layer 309.

[0154] Furthermore, the positive electrode 304 and negative electrode 307 used in the coin-type secondary battery 300 are each active The material layer only needs to be formed on one side.

[0155] The positive electrode can 301 and negative electrode can 302 contain nickel and aluminum, which are corrosion-resistant to the electrolyte. Metals such as titanium, or alloys of these or alloys of these with other metals (for example, stainless steel) Steel, etc. can be used. In addition, nickel or aluminum can be used to prevent corrosion by the electrolyte. It is preferable to coat with aluminum or the like. Positive electrode can 301 is positive electrode 304, and negative electrode can 302 is negative electrode 3 Connect each of them electrically to 07.

[0156] These negative electrode 307, positive electrode 304, and separator 310 are impregnated with the electrolyte, as shown in Figure 4(B As shown in the image, with the positive electrode can 301 at the bottom, the positive electrode 304, separator 310, and negative electrode 307, The negative electrode cans 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are connected by a gasket 303. The coin-type secondary battery 300 is manufactured by crimping the parts together.

[0157] By using the positive electrode active material particles described in the previous embodiment for the positive electrode 304, high capacity and This can be used to create a coin-type secondary battery 300 with excellent rechargeable properties.

[0158] [Cylindrical rechargeable battery] Next, an example of a cylindrical secondary battery will be explained with reference to Figure 5. Cylindrical secondary battery 600 As shown in Figure 5(A), it has a positive electrode cap (battery cover) 601 on the top surface, and the sides and The bottom has a battery case (outer case) 602. These positive electrode cap and battery case (outer case) 6 02 is insulated by gasket (insulating packing) 610.

[0159] Figure 5(B) is a schematic diagram showing a cross-section of a cylindrical secondary battery. Inside can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are separated by a separator 605. A wound battery element is provided. Although not shown in the diagram, the battery element is centered around the center pin. It is wound up. Battery can 602 is closed at one end and open at the other end. This is a metal such as nickel, aluminum, or titanium that is corrosion-resistant to the electrolyte, or this These alloys or alloys of these with other metals (for example, stainless steel) can be used. Furthermore, to prevent corrosion from the electrolyte, it is preferable to coat the components with nickel, aluminum, etc. Inside the battery can 602, the positive electrode, negative electrode, and separator are wound together to form a battery element. It is sandwiched between a pair of opposing insulating plates 608 and 609. Furthermore, a battery element is provided. The inside of the battery can 602 is filled with a non-aqueous electrolyte (not shown). The non-aqueous electrolyte is A battery similar to a coin-type rechargeable battery can be used.

[0160] The positive and negative electrodes used in cylindrical secondary batteries are wound, so the active material is formed on both sides of the current collector. It is preferable to do so. A positive electrode terminal (positive electrode current collector lead) 603 is connected to the positive electrode 604. The negative electrode 606 is connected to the negative electrode terminal (negative electrode current collector lead) 607. The positive electrode terminal 603 and The negative terminal 607 can be made of metal material such as aluminum. Positive terminal Terminal 603 is resistance-welded to the safety valve mechanism 612, and the negative terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 612 is a PTC element (Positive Temperature). It is electrically connected to the positive electrode cap 601 via Coefficient 611. The safety valve mechanism 612 activates when the rise in internal pressure of the battery exceeds a predetermined threshold, and the positive electrode cap 60 This disconnects the electrical connection between 1 and the positive electrode 604. Also, the PTC element 611 is temperature This is a thermal resistance element whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current. This prevents abnormal heat generation. The PTC element contains barium titanate (BaTiO3). Semiconductor ceramics and the like can be used.

[0161] By using the positive electrode active material particles described in the previous embodiment for the positive electrode 604, high capacity and This allows for the creation of a cylindrical secondary battery 600 with excellent operating characteristics.

[0162] [Example of an energy storage device structure] Another example of the structure of an energy storage device will be explained using Figures 6 to 10.

[0163] Figures 6(A) and 6(B) show external views of the energy storage device. The energy storage device is a circuit base It has a plate 900 and a secondary battery 913. A label 910 is attached to the secondary battery 913. Furthermore, as shown in Figure 6(B), the energy storage device has terminal 951 and terminal 952, It has antenna 914 and antenna 915.

[0164] The circuit board 900 has terminal 911 and circuit 912. Terminal 911 is connected to terminal 95 1. It is connected to terminal 952, antenna 914, antenna 915, and circuit 912. Multiple terminals 911 are provided, and each of the multiple terminals 911 is designated as a control signal input terminal and a power supply terminal. You can also refer to them as children.

[0165] Circuit 912 may be provided on the back surface of circuit board 900. Note that antenna 914 Furthermore, the antenna 915 is not limited to a coil shape, but may be, for example, linear or plate-shaped. Planar antenna, aperture antenna, traveling wave antenna, EH antenna, magnetic field antenna, dielectric You may use an antenna such as a body antenna. Alternatively, you may use antenna 914 or antenna 915. This may be a flat conductor. This flat conductor functions as one of the conductors for electric field coupling. This is possible. In other words, as one of the two conductors of the capacitor, A Antenna 914 or antenna 915 may be activated. This will create an electromagnetic field, a magnetic field. Furthermore, it is also possible to exchange power using an electric field.

[0166] The line width of antenna 914 is preferably larger than the line width of antenna 915. This allows for a greater amount of power to be received by antenna 914.

[0167] The energy storage device has a layer 916 between antennas 914 and 915 and the secondary battery 913. It has the function of shielding electromagnetic fields, for example, from secondary batteries 913. For 916, for example, a magnetic material can be used.

[0168] Note that the structure of the energy storage device is not limited to that shown in Figure 6.

[0169] For example, as shown in Figures 7(A-1) and 7(A-2), Figures 6(A) and 6(B) Antennas may be provided on each of the opposing pairs of surfaces of the secondary battery 913 shown. Figure 7(A-1) is an external view of the pair of surfaces as seen from one side, and Figure 7(A-2) is This is an external view of the pair of surfaces as seen from the other side. Note that Figures 6(A) and 6(B) are shown below. For parts of the energy storage device shown, please refer to the explanation of the energy storage device shown in Figures 6(A) and 6(B). It can be used as appropriate.

[0170] As shown in Figure 7(A-1), a layer 916 is sandwiched between one of the pair of surfaces of the secondary battery 913. An incubator 914 is provided, and as shown in Figure 7(A-2), the other side of the secondary battery 913 An antenna 915 is provided on one side, with layer 917 in between. Layer 917 is, for example, a secondary battery 913 It has the function of shielding electromagnetic fields. For layer 917, for example, a magnetic material can be used. can.

[0171] By adopting the above structure, the size of both antenna 914 and antenna 915 can be increased. It can be done.

[0172] Alternatively, as shown in Figures 7(B-1) and 7(B-2), in Figures 6(A) and 6(B) In the secondary battery 913 shown, separate antennas may be provided on each of the two opposing faces. Figure 7(B-1) is an external view of the pair of surfaces as seen from one side, and Figure 7(B-2) This is an external view of the pair of surfaces mentioned above, seen from the other side. Note that Figures 6(A) and 6(B) For parts that are the same as the energy storage device shown, see the explanation of the energy storage device shown in Figures 6(A) and 6(B). This can be used as appropriate.

[0173] As shown in Figure 7(B-1), a layer 916 is sandwiched between one of the pair of surfaces of the secondary battery 913. An antenna 914 and an antenna 915 are provided, and as shown in Figure 7(B-2), a secondary battery 9 An antenna 918 is provided on the other side of the pair of 13 faces, with a layer 917 in between. Antenna 918 For example, it has the function to communicate data with external devices. Antenna 918 For example, an antenna with a shape applicable to antenna 914 and antenna 915 can be applied. This is possible. The communication method between the energy storage device and other equipment via antenna 918 is NF. It is possible to apply response methods such as C, which can be used between energy storage devices and other equipment. can.

[0174] Alternatively, as shown in Figure 8(A), the secondary battery 913 shown in Figures 6(A) and 6(B) is displayed. A display device 920 may be provided. The display device 920 receives electrical signals from terminal 911 via terminal 919. They are connected precisely. Note that even if a label 910 is not provided in the area where the display device 920 is provided, Good. Note that for the same parts as the energy storage device shown in Figures 6(A) and 6(B), see Figure 6(A) The explanation of the energy storage device shown in Figure 6(B) can be appropriately referenced.

[0175] The display device 920 may display, for example, an image indicating whether or not it is charging, an image indicating the amount of stored power, etc. It may be displayed. The display device 920 may be, for example, electronic paper, liquid crystal display device, etc. A trollescent (also known as EL) display device can be used. For example, an electronic paper By using a supercharger, the power consumption of the display device 920 can be reduced.

[0176] Alternatively, as shown in Figure 8(B), the secondary battery 913 shown in Figures 6(A) and 6(B) is connected to the battery. A sensor 921 may be provided. The sensor 921 is electrically connected to terminal 911 via terminal 922. It will be connected. Note that the same parts as the energy storage device shown in Figures 6(A) and 6(B) are shown in Figure The explanation of the energy storage device shown in 6(A) and Figure 6(B) can be used as appropriate.

[0177] Sensor 921 can measure, for example, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, Light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, electric current, voltage, power, radiation, It should have the ability to measure flow rate, humidity, gradient, vibration, odor, or infrared radiation. i. By providing the sensor 921, for example, data indicating the environment in which the energy storage device is located can be collected. It can also detect parameters (such as temperature) and store them in the memory within circuit 912.

[0178] Furthermore, an example of the structure of the secondary battery 913 will be explained using Figures 9 and 10.

[0179] The secondary battery 913 shown in Figure 9(A) has terminals 951 and 952 inside the housing 930. It has a wound body 950. The wound body 950 is impregnated with an electrolyte inside the housing 930. Terminal 952 is in contact with the housing 930, and terminal 951 is in contact with the housing by using insulating material, etc. It is not in contact with the body 930. Note that in Figure 9(A), for convenience, the housing 930 is separated and shown in the figure. Although shown, in reality the wound body 950 is covered by the housing 930, and terminals 951 and 952 It extends outside the casing 930. The casing 930 is made of a metal material (for example, aluminum). (etc.) or resin materials can be used.

[0180] Furthermore, as shown in Figure 9(B), the housing 930 shown in Figure 9(A) is formed from multiple materials. It may be done. For example, the secondary battery 913 shown in Figure 9(B) has a housing 930a and a housing 930 b is bonded together, and the area enclosed by housing 930a and housing 930b is the wound body 950 A system is in place.

[0181] For the enclosure 930a, insulating materials such as organic resins can be used. In particular, the antenna By using a material such as organic resin on the surface where the na is formed, the electric field produced by the secondary battery 913 is created. This can suppress shielding. If the shielding of the electric field by the housing 930a is small, the housing 930a Antennas such as antenna 914 and antenna 915 may be installed inside the enclosure 930b. For example, metal materials can be used.

[0182] Furthermore, the structure of the wound body 950 is shown in Figure 10. The wound body 950 consists of a negative electrode 931 and It has a positive electrode 932 and a separator 933. The wound body 950 sandwiches the separator 933. Then the negative electrode 931 and the positive electrode 932 are stacked on top of each other, and the stacked sheet is wound up. It is a body. Furthermore, the stacking of the negative electrode 931, the positive electrode 932, and the separator 933 is further Multiple layers can be stacked.

[0183] The negative electrode 931 is connected to terminal 911 shown in Figure 6 via either terminal 951 or terminal 952. The positive terminal 932 is connected to terminal 911 shown in Figure 6 via terminal 951 and the other terminal 952. It connects to the network.

[0184] By using the positive electrode active material particles 100 described in the previous embodiment for the positive electrode 932, high volume By adjusting the quantity, a secondary battery 913 with excellent cycle characteristics can be created.

[0185] [Laminated rechargeable battery] Next, an example of a laminate-type secondary battery will be explained with reference to Figures 11 to 17. If a laminate-type secondary battery has a flexible structure, the number of flexible parts can be reduced. If implemented in electronic devices that also possess some of these features, the secondary battery will also bend in accordance with the deformation of the electronic device. It's also possible.

[0186] Using Figure 11, we will explain the laminated type secondary battery 980. The next battery 980 has a wound body 993 as shown in Figure 11(A). The wound body 993 has a negative electrode 99 It has 4, a positive electrode 995, and a separator 966. The wound body 993 is explained in Figure 10. Similar to the wound body 950, the negative electrode 994 and the positive electrode 995 overlap with the separator 966 in between. These are laminated sheets that are then rolled up.

[0187] The number of layers in the stack consisting of the negative electrode 994, positive electrode 995, and separator 966 is required. The design should be appropriate depending on the capacitance and element volume. The negative electrode 994 is connected to the lead electrode 997 and One end of electrode 998 is connected to a negative electrode current collector (not shown), and positive electrode 995 is connected to a lead The electrode 997 and the other lead electrode 998 are connected to a positive electrode current collector (not shown). .

[0188] As shown in Figure 11(B), there is a film 981 which will be the outer casing and a film 9 having a recess The aforementioned wound body 993 is housed in the space formed by bonding 82 and the other by heat pressing or the like. By doing so, a secondary battery 980 can be manufactured as shown in Figure 11(C). 93 has lead electrodes 997 and 998, and a film 981 and a recess The film 982 is impregnated with an electrolyte solution inside it.

[0189] Film 981 and film 982 having a recess are made of a metal material such as aluminum. Materials and resins can be used. Film 981 and film 982 having recesses If a resin material is used as the material, when an external force is applied, the film 981 and the recess will be affected. The film 982 having can be deformed, and a flexible secondary battery can be manufactured. It is possible.

[0190] Furthermore, Figures 11(B) and 11(C) show examples where two films are used. By folding a single film, a space is formed, and the aforementioned wound body 9 is placed in that space. You may store 93.

[0191] By using the positive electrode active material particles 100 described in the previous embodiment for the positive electrode 995, high volume By adjusting the quantity, it is possible to create a secondary battery 980 with excellent cycle characteristics.

[0192] Figure 11 also shows a secondary battery having a wound body in a space formed by a film that serves as the outer casing. We have explained the example of 980, but for example, as shown in Figure 12, the film that forms the outer casing In the formed space, a secondary battery having multiple strip-shaped positive electrodes, separators, and negative electrodes is formed. That's good too.

[0193] The laminated secondary battery 500 shown in Figure 12(A) consists of a positive electrode current collector 501 and a positive electrode active The positive electrode 503 has a material layer 502, and the negative electrode has a current collector 504 and a negative electrode active material layer 505. It has a negative electrode 506, a separator 507, an electrolyte 508, and an outer casing 509. A separator 507 is installed between the positive electrode 503 and the negative electrode 506 located within the housing 509. Furthermore, the inside of the outer casing 509 is filled with electrolyte 508. The electrolyte 508 contains, The electrolyte shown in Embodiment 2 can be used.

[0194] In the laminate-type secondary battery 500 shown in Figure 12(A), the positive electrode current collector 501 and The negative electrode current collector 504 also serves as a terminal for obtaining electrical contact with the outside. Therefore, Parts of the polar current collector 501 and the negative polar current collector 504 are exposed to the outside from the outer casing 509. They may also be placed in the casing 509. Furthermore, without exposing them to the outside, lead electrodes are used to connect the lead electrodes to the positive electrode current collector 501, or the negative electrode. The lead electrodes may be exposed to the outside by ultrasonic bonding with the current collector 504.

[0195] In the laminated secondary battery 500, the outer casing 509 is made of, for example, polyethylene, On a film made of materials such as polypropylene, polycarbonate, ionomer, and polyamide, A thin film of a highly flexible metal such as aluminum, stainless steel, copper, or nickel is provided, and further, An insulating synthetic material such as polyamide resin or polyester resin is used as the outer surface of the exterior body on a thin metal film. A three-layer laminate film with a resin film can be used.

[0196] Furthermore, an example of the cross-sectional structure of the laminate-type secondary battery 500 is shown in Figure 12(B). Figure 12 (A) shows an example with two current collectors for simplicity, but in reality, multiple electrodes are used. It is composed of layers.

[0197] In Figure 12(B), the number of electrode layers is set to 16 as an example. However, the secondary battery 500 is flexible. In Figure 12(B), the negative electrode current collector 504 has 8 layers. The positive electrode current collector 501 has a structure of 8 layers, for a total of 16 layers. Figure 12(B) shows the negative electrode. This shows a cross-section of the extraction section, where eight layers of negative electrode current collectors 504 are ultrasonically bonded. In theory, the number of electrode layers is not limited to 16; it can be more or fewer. In combination, it can be made into a secondary battery with a larger capacity. Also, the number of electrode layers is small. In some cases, this allows for a thinner design and a rechargeable battery with excellent flexibility.

[0198] Here, an example of the external view of the laminate-type secondary battery 500 is shown in Figures 13 and 14. Figures 13 and 14 show the positive electrode 503, negative electrode 506, separator 507, casing 509, and positive electrode ri It has a lead electrode 510 and a negative lead electrode 511.

[0199] Figure 15(A) shows the external view of the positive electrode 503 and the negative electrode 506. The positive electrode 503 is the positive electrode current collector 5 It has 01, and the positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. Pole 503 has a region (hereinafter referred to as the tab region) in which the positive electrode current collector 501 is partially exposed. The electrode 506 has a negative electrode current collector 504, and the negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. This has been done. Also, the negative electrode 506 is the region where the negative electrode current collector 504 is partially exposed, i.e., the tab. It has a region. The area and shape of the tab regions of the positive and negative electrodes are as shown in the example in Figure 15(A). It's not limited.

[0200] [Method for manufacturing laminated rechargeable batteries] Here, an example of a method for manufacturing a laminate-type secondary battery, whose external view is shown in Figure 13, is shown in Figure 1. This will be explained using 5(B) and (C).

[0201] First, the negative electrode 506, separator 507, and positive electrode 503 are stacked. (See Figure 15(B) for stacking.) The negative electrode 506, separator 507, and positive electrode 503 are shown. Here, there are 5 sets of negative electrodes and positive electrodes. An example using four sets is shown. Next, the joining of the tab regions of the positive electrode 503 and the tab of the outermost positive electrode. The positive lead electrode 510 is joined to the b region. For joining, for example, ultrasonic welding is used. Similarly, the joining of the tab regions of the negative electrode 506 and the negative electrode to the tab region of the outermost negative electrode The lead electrodes 511 are joined.

[0202] Next, the negative electrode 506, separator 507, and positive electrode 503 are placed on the outer casing 509.

[0203] Next, as shown in Figure 15(C), fold the outer casing 509 along the dashed line. After that, the outer periphery of the exterior body 509 is joined. For joining, for example, heat compression bonding may be used. At that time, a part (or one side) of the outer casing 509 was made so that the electrolyte 508 could be added later. A region that is not connected to the main structure (hereinafter referred to as the inlet) is provided.

[0204] Next, the electrolyte 508 is guided to the inside of the outer casing 509 through the inlet provided in the outer casing 509. The electrolyte 508 can be introduced under reduced pressure or inert gas conditions. This is preferable. And finally, the inlet is joined. In this way, a laminate-type secondary battery is formed. A secondary battery 500 can be manufactured.

[0205] By using the positive electrode active material particles 100 described in the previous embodiment for the positive electrode 503, high volume By adjusting the quantity, it is possible to create a secondary battery 500 with excellent cycle characteristics.

[0206] [Bendable rechargeable battery] Next, an example of a bendable secondary battery will be described with reference to Figures 16 and 17. ru.

[0207] Figure 16(A) shows a schematic top view of the bendable battery 250. Figure 16(B1) (B2) and (C) correspond to the cutting lines C1-C2 and C3-C in Figure 16(A), respectively. 4. This is a schematic cross-sectional view at the cutting line A1-A2. The battery 250 consists of an outer casing 251 and an outer casing. The body 251 has a positive electrode 211a and a negative electrode 211b housed inside. Electrically connected lead 212a, and lead 2 electrically connected to the negative electrode 211b 12b extends to the outside of the outer casing 251. Furthermore, within the area enclosed by the outer casing 251, In addition to the positive electrode 211a and the negative electrode 211b, an electrolyte (not shown) is sealed inside.

[0208] The positive electrode 211a and negative electrode 211b of battery 250 will be explained using Figure 17. Figure 17(A) shows the stacking order of the positive electrode 211a, the negative electrode 211b, and the separator 214. This is a perspective view. Figure 17(B) shows the positive electrode 211a and the negative electrode 211b, as well as the leads. This is a perspective view showing lead 212a and lead 212b.

[0209] As shown in Figure 17(A), the battery 250 has multiple strip-shaped positive electrodes 211a, multiple strips It has a negative electrode 211b and a plurality of separators 214. Positive electrode 211a and negative electrode 21 Each 1b has a protruding tab portion and a portion other than the tab. One side of the positive electrode 211a A positive electrode active material layer is formed on the part other than the tab of the negative electrode 211b, and on the part other than the tab on one side of the negative electrode 211b A negative electrode active material layer is formed.

[0210] The sides of the positive electrode 211a that do not have a positive electrode active material layer formed on them, and the negative electrode active The positive electrode 211a and the negative electrode 211b are positioned so that the surfaces without a material layer are in contact with each other. Layers are added.

[0211] Furthermore, the surface on which the positive electrode active material layer of the positive electrode 211a is formed and the negative electrode active material layer of the negative electrode 211b A separator 214 is provided between the formed surfaces. In Figure 17, the separator is shown for clarity. Reference numeral 214 is shown as a dotted line.

[0212] Also, as shown in Figure 17(B), the multiple positive electrodes 211a and leads 212a are connected at the joint 21 They are electrically connected at 5a. Also, multiple negative electrodes 211b and leads 212b are connected at the joint. It is electrically connected at 215b.

[0213] Next, the exterior body 251 will be explained using Figures 16(B1), (B2), (C), and (D). do.

[0214] The outer casing 251 has a film-like shape and sandwiches the positive electrode 211a and the negative electrode 211b. It is folded in half. The outer casing 251 has a folded portion 261 and a pair of sealing portions It has a 262 and a sealing portion 263. The pair of sealing portions 262 are positive electrode 211a and It is provided on either side of the negative electrode 211b and can also be called a side seal. Also, seal portion 2 Section 63 has a portion that overlaps with leads 212a and 212b, and is also called the top seal. It is possible.

[0215] The outer casing 251 has ridges 271 and valleys in the portion that overlaps with the positive electrode 211a and the negative electrode 211b. It is preferable that the 272 have a wave shape arranged alternately. Also, the sealing portion 2 of the outer casing 251 It is preferable that 62 and the sealing portion 263 are flat.

[0216] Figure 16(B1) is a cross-section cut at the point where it overlaps with ridge line 271, and Figure 16(B2) is This is a cross-section taken at the point where it overlaps with valley line 272. Figures 16(B1) and (B2) both show the electric This corresponds to the cross-section in the width direction of the pond 250 and the positive electrode 211a and negative electrode 211b.

[0217] Here, the end of the negative electrode 211b in the width direction, that is, the end of the negative electrode 211b, and the seal portion 26 Let the distance between point 2 and point 2 be distance La. When battery 250 is subjected to deformation such as bending, as will be described later... The positive electrode 211a and the negative electrode 211b are deformed so that they are offset from each other in the longitudinal direction. In this case, if the distance La is too short, the outer casing 251 and the positive electrode 211a and negative electrode 211b will be too close together. Scratching can cause damage to the outer casing 251. In particular, the metal film of the outer casing 251 may become exposed. If exposed, the metal film may be corroded by the electrolyte. Therefore, It is preferable to set the distance La as long as possible. On the other hand, it is preferable not to make the distance La too large. This would increase the volume of the 250 battery.

[0218] Furthermore, the thicker the combined thickness of the stacked positive electrode 211a and negative electrode 211b, the greater the negative electrode 21 It is preferable to increase the distance La between 1b and the seal portion 262.

[0219] More specifically, the total thickness of the stacked positive electrode 211a and negative electrode 211b is defined as thickness t. When this happens, the distance La is 0.8 times or more and 3.0 times or less the thickness t, preferably 0.9 times or more and 2 times It is preferable that the ratio is 0.5 times or less, more preferably 1.0 times or more and 2.0 times or less. Distance La By setting this range, we can realize a compact battery that is also highly reliable against bending. ru.

[0220] Furthermore, when the distance between the pair of sealing portions 262 is denoted as distance Lb, distance Lb is set to the positive electrode 211 Make it sufficiently larger than the width of a and the negative electrode 211b (here, the width Wb of the negative electrode 211b). This is preferable. This ensures that when the battery 250 is repeatedly bent or otherwise deformed, the correct Even if the electrode 211a and the negative electrode 211b come into contact with the outer casing 251, the positive electrode 211a and the negative electrode Since a portion of 211b can be shifted in the width direction, the positive electrode 211a and the negative electrode 211b This effectively prevents the outer casing 251 from rubbing against each other.

[0221] For example, the difference between the distance La between the pair of sealing portions 262 and the width Wb of the negative electrode 211b is positive. The thickness t of electrode 211a and negative electrode 211b is 1.6 times or more and 6.0 times or less, preferably 1.8 It is preferable that the ratio be between 2.0 and 4.0 times, and more preferably between 2.0 and 4.0 times. stomach.

[0222] In other words, it is desirable that the distance Lb, width Wb, and thickness t satisfy the relationship shown in Equation 1 below. It seems so.

[0223]

number

[0224] Here, a is 0.8 or more and 3.0 or less, preferably 0.9 or more and 2.5 or less, more preferably The value of 'k' satisfies 1.0 or greater and 2.0 or less.

[0225] Furthermore, Figure 16(C) shows a cross-section including lead 212a, battery 250, positive electrode 211a This corresponds to the longitudinal cross-section of the negative electrode 211b. As shown in Figure 16(C), the bent portion In 261, the longitudinal ends of the positive electrode 211a and the negative electrode 211b, and the outer casing 251 It is preferable to have a space 273 between them.

[0226] Figure 16(D) shows a schematic cross-sectional view of the battery 250 when bent. This corresponds to the cross-section at the cutting line B1-B2 in Figure 16(A).

[0227] When the battery 250 is bent, a portion of the outer casing 251 located on the outside of the bend stretches and moves inward. Other parts deform to shrink. More specifically, the parts located on the outside of the outer casing 251 The wave is deformed so that the amplitude of the wave is small and the period of the wave is large. Meanwhile, the outer casing 25 The part located inside 1 is deformed so that the wave amplitude is large and the wave period is small. In this way, as the outer casing 251 deforms, the force acting on the outer casing 251 due to bending Because the stress is relieved, the material that makes up the exterior 251 does not need to expand or contract. As a result, the outer casing 251 is not damaged, and the battery 250 can be bent with minimal force.

[0228] Also, as shown in Figure 16(D), when the battery 250 is bent, the positive electrode 211a and the negative electrode 2 11b and the other are relatively shifted. At this time, multiple stacked positive electrodes 211a and negative electrodes are shifted. Since one end of pole 211b on the sealing portion 263 side is fixed by the fixing member 217, it is not foldable. Each part shifts such that the amount of shift increases the closer it is to the recessed part 261. As a result, the positive electrode 2 The stress on 11a and the negative electrode 211b is relieved, and the positive electrode 211a and the negative electrode 211b themselves The body does not need to expand or contract. As a result, the positive electrode 211a and the negative electrode 211b are not damaged. It can bend a 250mAh battery.

[0229] Furthermore, there is a space 273 between the positive electrode 211a and the negative electrode 211b and the outer casing 251. By doing so, when bent, the positive electrode 211a and negative electrode 211b located on the inside become the outer casing 2 It can shift relative to 51 without making contact.

[0230] The battery 250 illustrated in Figures 16 and 17 can withstand repeated bending and straightening, and its casing remains intact. Damage to the positive electrode 211a and negative electrode 211b is less likely to occur, and the battery characteristics do not deteriorate. This is a battery. The positive electrode 211a of the battery 250 is connected to the positive electrode activity described in the previous embodiment. By using material particles 100, it is possible to create a battery with even higher capacity and superior cycle characteristics. can.

[0231] (Embodiment 4) This embodiment describes an example of mounting a secondary battery, which is one aspect of the present invention, into an electronic device. I will reveal it.

[0232] First, as explained in part of Embodiment 3, a bendable secondary battery is mounted in an electronic device. Examples are shown in Figures 18(A) to (G). Electronic devices using a bendable secondary battery. For example, television equipment (also called television or television receiver), Monitors for computers, digital cameras, digital video cameras, digital photo frames, etc. Mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants Examples include sound reproduction devices and large game machines such as pachinko machines.

[0233] Furthermore, rechargeable batteries with flexible shapes can be attached to the interior or exterior walls of houses and buildings, or to automatic It can also be integrated to conform to the curved surfaces of the car's interior or exterior.

[0234] Figure 18(A) shows an example of a mobile phone. The mobile phone 7400 has a housing 740 In addition to the display unit 7402 incorporated into 1, there are also operation buttons 7403, an external connection port 7404, It is equipped with speaker 7405, microphone 7406, etc. Note that mobile phone 7400 has two It has a secondary battery 7407. The secondary battery 7407 of the present invention is used in the above secondary battery 7407. This allows us to provide lightweight and long-lasting mobile phones.

[0235] Figure 18(B) shows the mobile phone 7400 in a curved state. When 00 is deformed by an external force and the whole thing is bent, the secondary electric charge located inside it The battery 7407 is also bent. Figure 18 shows the state of the bent secondary battery 7407 at that time. As shown in C), the 7407 secondary battery is a thin secondary battery. The 7407 secondary battery is bent. It is fixed in this state. Note that the secondary battery 7407 is electrically connected to the current collector 7409. It has lead electrodes.

[0236] Figure 18(D) shows an example of a bangle-type display device. The portable display device 7100 is It comprises a housing 7101, a display unit 7102, operation buttons 7103, and a secondary battery 7104. Figure 18(E) also shows the state of the bent secondary battery 7104. The secondary battery 7104 is When worn on the user's arm in a bent state, the casing deforms, causing part of the secondary battery 7104 to be damaged. The curvature of the curve changes across the entire curve. Note that the degree of curvature at any point in the curve is the radius of the corresponding circle. The value expressed as is the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Specifically, the half of the radius of curvature A portion of the main surface of the housing or secondary battery 7104, within a diameter range of 40 mm to 150 mm. Or the whole thing changes. The radius of curvature on the main surface of secondary battery 7104 is 40 mm or more 15 High reliability can be maintained within a range of 0 mm or less. The present invention applies to the secondary battery 7104 described above. By using a secondary battery of one form, a lightweight and long-lasting portable display device can be provided.

[0237] Figure 18(F) shows an example of a wristwatch-type personal information terminal. Personal information terminal 7200 The components are: housing 7201, display unit 7202, band 7203, buckle 7204, and operation button 7 It is equipped with terminals 205 and input / output terminals 7206, etc.

[0238] The 7200 mobile information terminal offers mobile phone calls, email, document viewing and creation, music playback, and more. It can run various applications such as internet communication and computer games. Cut.

[0239] The display unit 7202 has a curved display surface, and displays information along the curved surface. It is possible to do so. In addition, the display unit 7202 is equipped with a touch sensor, and the screen can be touched with a finger or stylus. It can be operated by touching it. For example, icon 7 displayed on the display unit 7202 Touching 207 will launch the application.

[0240] The 7205 control button is used for time setting, as well as power on / off, wireless communication on, and more. Various functions such as operation, activation and deactivation of silent mode, and activation and deactivation of power saving mode. It can be made to hold. For example, the operating system built into the personal digital assistant 7200 The system also allows you to freely configure the function of the control button 7205.

[0241] Furthermore, the 7200 portable information terminal is capable of performing standardized short-range wireless communication. For example, by communicating with a wireless headset, hands-free operation is possible. You can also make calls.

[0242] Furthermore, the portable information terminal 7200 is equipped with an input / output terminal 7206, and can connect to other information terminals. Data can be exchanged directly via this. Also, charging is possible via input / output terminal 7206. It can also perform electrical operations. Note that charging is done wirelessly without using input / output terminal 7206. You may go.

[0243] The display unit 7202 of the portable information terminal 7200 has a secondary battery according to one aspect of the present invention. By using a secondary battery according to one aspect of the present invention, a lightweight and long-lasting portable information terminal can be provided. For example, the secondary battery 7104 shown in Figure 18(E) is placed inside the housing 7201 in a curved shape. It can be incorporated either in its original state or in a flexible state within the band 7203.

[0244] The personal information terminal 7200 preferably has a sensor. For example, a fingerprint sensor. Human body sensors such as pulse sensors and body temperature sensors, as well as touch sensors, pressure sensors, and accelerometers. It is preferable that sensors, etc., be installed.

[0245] Figure 18(G) shows an example of an armband-type display device. The display device 7300 is a display unit The present invention has a secondary battery having 7304. Furthermore, the display device 7300 is The display unit 7304 can also be equipped with a touch sensor, and it can also function as a portable information terminal. It is also possible to do so.

[0246] The display unit 7304 has a curved display surface, and displays are performed along the curved display surface. This is possible. In addition, the display device 7300 can display information via standardized short-range wireless communication. The situation can be changed.

[0247] Furthermore, the display device 7300 is equipped with input / output terminals and can be directly connected to other information terminals via connectors. It can exchange data. It can also be charged via its input / output terminals. Furthermore, charging may be performed wirelessly without using input / output terminals.

[0248] By using a secondary battery according to one aspect of the present invention as the secondary battery of the display device 7300, We can provide lightweight and long-lasting display devices.

[0249] Furthermore, an example of mounting the secondary battery with good cycle characteristics shown in the previous embodiment into an electronic device is provided. This will be explained using Figures 18(H), 19, and 20.

[0250] By using a secondary battery according to one aspect of the present invention as a secondary battery in everyday electronic devices, a lightweight and long-lasting battery can be achieved. We can provide essential products. For example, everyday electronic devices such as electric toothbrushes and electric shavers. Examples include electric beauty devices, and the rechargeable batteries for these products are designed to be easy for the user to hold. The idea is to create a rechargeable battery that is small, lightweight, and high-capacity, with a stick-like shape.

[0251] Figure 18(H) is a perspective view of a device also known as a tobacco-containing smoking device (electronic cigarette). In Figure 18(H), the e-cigarette 7500 includes an atomizer 7501 containing a heating element, and The tomizer 7501 is powered by a secondary battery 7504, and liquid supply bottles and sensors are also included. It consists of cartridge 7502. To enhance safety, the secondary battery 7504 A protection circuit to prevent overcharging and over-discharging may be electrically connected to the secondary battery 7504. (Figure 18) The secondary battery 7504 shown in H) has external terminals so that it can be connected to a charging device. The 7504 secondary battery is the tip when held, so the total length is short, and heavy A small quantity is desirable. A secondary battery according to one aspect of the present invention has high capacity and good cycle characteristics. Therefore, a small and lightweight e-cigarette 7 that can be used for extended periods of time. We can offer 500.

[0252] Next, Figures 19(A) and 19(B) show an example of a foldable tablet device. As shown in Figures 19(A) and 19(B), the tablet terminal 9600 has a housing 963 0a, housing 9630b, movable part 9640 connecting housing 9630a and housing 9630b, front Display unit 9631, display mode switching switch 9626, power switch 9627, power saving mode It has a code change switch 9625, a fastener 9629, and an operating switch 9628. The display section 9631 uses a flexible panel, resulting in a tab with a wider display area. It can be used as a tablet terminal. Figure 19(A) shows the tablet terminal 9600 in an open state. Figure 19(B) shows the tablet terminal 9600 in a closed state.

[0253] Furthermore, the tablet terminal 9600 stores inside the housings 9630a and 9630b. It has an electric body 9635. The electric body 9635 passes through the movable part 9640 and the housing 9630a and the housing It is provided across body 9630b.

[0254] The display unit 9631 can have a portion of it designated as a touch panel area, and the displayed operation keys Data can be entered by touching the screen. Additionally, the touch panel keyboard display can be turned off. By touching the location where the replacement button is displayed with your finger or stylus, the display unit 9631 Keyboard buttons can be displayed.

[0255] Additionally, the display mode switch 9626 changes the display orientation, such as portrait or landscape. You can switch between modes, such as switching between black and white and color displays. Power saving mode switching... The switch 9625 is used by the light sensor built into the tablet terminal 9600. The display brightness can be optimized according to the amount of ambient light at the time. (Tablet device) In addition to optical sensors, other sensors such as gyroscopes and accelerometers that detect tilt are also used. An output device may be built into the unit.

[0256] Figure 19(B) shows the closed state, and the tablet terminal consists of a housing 9630 and a solar cell 9 633, it has a charge / discharge control circuit 9634 including a DC-DC converter 9636. As the battery 9635, a secondary battery according to one aspect of the present invention is used.

[0257] Furthermore, since the tablet device 9600 is foldable, the casing 9630a can be folded in half when not in use. The casing 9630b can be folded so that it overlaps with the other casing. This protects the display unit 9631, thereby increasing the durability of the tablet terminal 9600. It is possible. Furthermore, the energy storage unit 9635 using a secondary battery according to one aspect of the present invention has high capacity and good size. The 9600 tablet device possesses a unique characteristic that allows for extended use over long periods. We can provide this.

[0258] In addition, there are various other tablet devices, as shown in Figures 19(A) and 19(B). Features that display information (still images, videos, text images, etc.), calendar, date or time. Functions to display such information on the display unit, and the information displayed on the display unit can be operated or edited via touch input. Features include touch input functionality and the ability to control processing through various software (programs). It may have, etc.

[0259] The touch panel is powered by a solar cell 9633 mounted on the surface of the tablet device. It can be supplied to the display unit or the video signal processing unit, etc. The solar cell 9633 is It can be installed on one or both sides of the housing 9630, and efficiently charges the energy storage unit 9635. It can be configured as follows.

[0260] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 19(B) are shown in Figure 19. (C) shows a block diagram and provides an explanation. Figure 19(C) shows a solar cell 9633 and a power storage device 96 35. DC-DC converter 9636, converter 9637, switch SW1 to SW3, The display unit 9631 is shown, along with the energy storage unit 9635, the DC-DC converter 9636, and Converter 9637, switches SW1 to SW3, and the charge / discharge control circuit 9 shown in Figure 19(B) This corresponds to the section for 634.

[0261] First, let's explain an example of how the solar cell 9633 operates when generating electricity using ambient light. The electricity generated by the solar cells is converted into a DC-DC converter to provide the voltage necessary to charge the 9635 energy storage unit. The converter 9636 performs voltage boosting or bucking. Then, the solar power is used to control the operation of the display unit 9631. When power from pond 9633 is used, switch SW1 is turned ON, and converter 963 In step 7, the voltage is increased or decreased to the required voltage for the display unit 9631. Also, the display unit 963 If you do not want to display in step 1, turn switch SW1 off and switch SW2 on. The configuration should be such that the energy storage unit 9635 is charged.

[0262] While solar cell 9633 is shown as an example of a power generation method, it is not particularly limited to this method. Storage using other power generation methods such as piezoelectric elements (piezo elements) and thermoelectric elements (Peltier elements) The configuration may also involve charging the battery 9635. For example, power may be transmitted and received wirelessly (contactlessly). This includes contactless power transmission modules that charge via this method, as well as configurations that combine this with other charging methods. You may do so.

[0263] Figure 20 shows an example of another electronic device. In Figure 20, the display device 8000 is the present invention. This is an example of an electronic device using a secondary battery 8004 according to one embodiment. Specifically, the display device 80 00 corresponds to a display device for receiving TV broadcasts, and consists of a housing 8001, a display unit 8002, and a speaker. It has a part 8003, a secondary battery 8004, etc. A secondary battery 8004 according to one aspect of the present invention is It is located inside the enclosure 8001. The display device 8000 receives power from the commercial power supply. You can receive power from it, or you can use the power stored in the secondary battery 8004. Therefore, even when power cannot be supplied from the commercial power source due to a power outage or the like, according to one aspect of the present invention By using the secondary battery 8004 as an uninterruptible power supply, the display device 8000 can be used. Yes.

[0264] The display unit 8002 has light-emitting elements such as liquid crystal display devices and organic EL elements in each pixel. Optical devices, electrophoresis display devices, DMDs (Digital Micromirror Dev ice), PDP (Plasma Display Panel), FED (Field Semiconductor display devices such as Emission Displays can be used.

[0265] In addition to being used for receiving TV broadcasts, the display devices are also used for personal computers and for displaying advertisements. This includes all information display devices.

[0266] In Figure 20, the fixed lighting device 8100 is a secondary battery 8 according to one aspect of the present invention. This is an example of an electronic device using 103. Specifically, the lighting device 8100 has a housing 8101, It has a light source 8102, a secondary battery 8103, etc. In Figure 20, the secondary battery 8103 is located in the housing 8 For example, consider the case where 101 and the light source 8102 are installed inside the ceiling 8104. Although shown, the secondary battery 8103 may also be located inside the housing 8101. The device 8100 can receive power from a commercial power source, or from a secondary battery 8103. It is also possible to use stored power. Therefore, in the event of a power outage, etc., power supply from commercial power source Even when it is not possible to receive a power supply, the secondary battery 8103 according to one aspect of the present invention can be used as an uninterruptible power supply. This makes it possible to use the lighting device 8100.

[0267] Figure 20 illustrates a fixed lighting device 8100 installed on the ceiling 8104. However, in one aspect of the present invention, the secondary battery is located on the side wall 8105, floor, and other surfaces besides the ceiling 8104. It can also be used in fixed lighting devices installed in windows such as 8106 and 8107, and also in tables It can also be used in overhead lighting fixtures and other applications.

[0268] Furthermore, the light source 8102 can use an artificial light source that artificially obtains light using electricity. Yes, it is possible. Specifically, this includes discharge lamps such as incandescent light bulbs and fluorescent lamps, and LEDs and organic EL elements. Optical elements are an example of the artificial light sources mentioned above.

[0269] In Figure 20, the air conditioner having an indoor unit 8200 and an outdoor unit 8204 is This is an example of an electronic device using a secondary battery 8203 according to one aspect of the present invention. Specifically, the room The internal unit 8200 includes a housing 8201, an air outlet 8202, a secondary battery 8203, etc. (Figure 20) The example given is that the secondary battery 8203 is installed in the indoor unit 8200, but The next battery 8203 may be located in the outdoor unit 8204. Alternatively, it may be located in the indoor unit 8200 and the room The secondary battery 8203 may be provided on both sides of the outdoor unit 8204. - It can also receive power from the commercial power supply, or stored in the secondary battery 8203 Electricity can also be used. In particular, both the indoor unit 8200 and the outdoor unit 8204 can use secondary batteries 8 If 203 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the secondary battery 8203 according to one aspect of the present invention as an uninterruptible power supply, Conditioner can be used.

[0270] Figure 20 shows a separate-type air conditioner consisting of an indoor unit and an outdoor unit. The example shown is an integrated air conditioner that has both the indoor and outdoor unit functions in a single housing. A secondary battery according to one aspect of the present invention can also be used in the conditioner.

[0271] In Figure 20, the electric refrigerator 8300 is a secondary battery 8304 according to one aspect of the present invention. This is an example of an electronic device using [a specific component]. Specifically, the electric refrigerator 8300 has a casing 8301, It has a refrigerator door 8302, a freezer door 8303, a secondary battery 8304, etc. In Figure 20, The secondary battery 8304 is located inside the casing 8301. The electric refrigerator 8300 is It can also receive power from the commercial power supply, or power stored in the secondary battery 8304 It is also possible to use this. Therefore, if power cannot be supplied from the commercial power source due to a power outage, etc. Even at times, by using the secondary battery 8304 according to one aspect of the present invention as an uninterruptible power supply, The 8300 refrigerator / freezer will become available for use.

[0272] Furthermore, during periods when electronic devices are not in use, especially the total amount of electricity that can be supplied by the commercial power source... Of these, during the time periods when the proportion of electricity actually used (called the electricity usage rate) is low, By storing power in the battery, the rate of power consumption outside of the above-mentioned time period is suppressed. It is possible. For example, in the case of the electric refrigerator 8300, when the temperature is low, the refrigerator door 83 02. At night when the freezer door 8303 is not opened or closed, power is supplied to the secondary battery 8304. Store. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 are opened and closed. During the daytime, by using the secondary battery 8304 as an auxiliary power source, daytime electricity usage The rate can be kept low.

[0273] In addition to the electronic devices described above, a secondary battery according to one aspect of the present invention can be mounted in any electronic device. Yes, it is possible. According to one aspect of the present invention, the cycle characteristics of the secondary battery are improved. According to one embodiment, a high-capacity secondary battery can be made, and therefore the secondary battery itself can be made small and lightweight. It can be converted. Therefore, a secondary battery, which is one aspect of the present invention, will be described in this embodiment. By incorporating it into electronic devices, it is possible to create electronic devices that have a longer lifespan and are lighter in weight. This embodiment can be implemented in appropriate combination with other embodiments.

[0274] (Embodiment 5) This embodiment shows an example in which a secondary battery according to one aspect of the present invention is mounted on a vehicle.

[0275] When a secondary battery is installed in a vehicle, it becomes a hybrid electric vehicle (HEV), an electric vehicle (EV), or This enables the realization of next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs). ru.

[0276] Figure 21 illustrates a vehicle using a secondary battery, which is one embodiment of the present invention. Figure 21(A The automobile 8400 shown in the image is an electric vehicle that uses an electric motor as a power source for driving. Alternatively, an electric motor and an engine can be appropriately selected and used as the power source for propulsion. This is a hybrid vehicle that can do so by using a secondary battery, which is one aspect of the present invention. This makes it possible to create a vehicle with a long driving range. In addition, the 8400 vehicle has a secondary battery. The secondary battery not only powers the electric motor 8406, but also the headlight 8401 and It can supply power to light-emitting devices such as room lights (not shown).

[0277] Furthermore, the secondary battery is used in the speedometer, tachometer, and other displays of the 8400 automobile. It can supply power to the display device. Furthermore, the secondary battery powers the navigation system of the 8400 automobile. It can supply power to semiconductor devices such as gate systems.

[0278] The automobile 8500 shown in Figure 21(B) has a secondary battery 8024 in the automobile 8500. It charges by receiving power from an external charging facility using methods such as the lag-in method or contactless power supply method. This is possible. Figure 21(B) shows the charging from the ground-mounted charging device 8021 to the automobile 8500. This shows the state in which the mounted secondary battery 8024 is being charged via cable 8022. When charging, the charging method and connector specifications are based on CHAdeMO (registered trademark) and Combo. The method may be carried out as appropriate in the prescribed manner. The charging device 8021 is a charging station installed in a commercial facility. It can be a power supply or a household power supply. For example, using plug-in technology, To charge the secondary battery 8024 installed in the automobile 8500 using an external power supply. This is possible. Charging is done by converting AC power to DC power via a conversion device such as an AC / DC converter. It can be done by swapping.

[0279] Although not shown in the diagram, a power receiving device is mounted on the vehicle, and power is supplied wirelessly from a ground-based power transmission device. It can also be charged by supplying power. In this contactless power supply method, the power transmission equipment is installed on the road or exterior wall. By incorporating this, charging can be performed not only when the vehicle is stopped but also while it is in motion. The electric system may be used to transmit and receive power between vehicles. Furthermore, the exterior of the vehicle Solar panels may be installed to charge the secondary battery while the vehicle is stopped or in motion. Electromagnetic induction and magnetic resonance methods can be used to supply power in this environment.

[0280] Furthermore, Figure 21(C) shows an example of a two-wheeled vehicle using a secondary battery according to one embodiment of the present invention. Figure 2 The scooter 8600 shown in 1(C) includes a secondary battery 8602, side mirrors 8601, and a directional indicator. It is equipped with an indicator light 8603. The secondary battery 8602 supplies power to the turn signal light 8603. It is possible.

[0281] Furthermore, the scooter 8600 shown in Figure 21(C) has a secondary battery 86 in the under-seat storage 8604. It can store 02. The secondary battery 8602 is small and the under-seat storage 8604 is small. It can also be stored in the under-seat storage compartment 8604.

[0282] According to one aspect of the present invention, the cycle characteristics of the secondary battery are improved, and the capacity of the secondary battery is increased. This allows for miniaturization and weight reduction of the secondary battery itself. Secondary battery Making the unit itself smaller and lighter would contribute to reducing the vehicle's weight, thus improving its range. Yes, it is possible. Furthermore, the secondary battery installed in the vehicle can also be used as a power source for things other than the vehicle itself. This is possible. In this case, for example, it is possible to avoid using commercial power during peak electricity demand. It is possible. If we can avoid using commercial power during peak electricity demand, we can save energy, and It can contribute to reducing carbon dioxide emissions. Also, if the cycle characteristics are good Because rechargeable batteries can be used for extended periods, the amount of rare metals used, including cobalt, can be reduced. It can be done.

[0283] This embodiment can be implemented in appropriate combination with other embodiments. [Examples]

[0284] In this example, positive electrode active material particles using cobalt as element M were fabricated and evaluated. .

[0285] <Fabrication of positive electrode active material particles> Sample 1 to Sample 1, with varying concentrations of lithium and cobalt sources. Positive electrode active material particles down to 0 were fabricated. Lithium carbonate (Li2CO3) was used as the starting material. Tricobalt tetroxide (Co3O4), magnesium oxide (MgO), and lithium fluoride ( LiF was used.

[0286] For each sample, the starting materials were lithium carbonate, tricobalt tetroxide, and magnesium oxide. The molar ratios of nesium and lithium fluoride were weighed to the values ​​shown in Table 1.

[0287] [Table 1]

[0288] Table 1 shows that the number of cobalt atoms in tricobalt tetroxide is relative to the number of lithium carbonate atoms and fluorine atoms. The sum of the number of lithium atoms contained in each of the lithium compounds is 1.0 in Sample 1. 00x, 1.010x in Sample 2, 1.020x in Sample 3, Sa Sample 4 uses a 1.030x multiplier, Sample 5 uses a 1.035x multiplier, and Sample 6 uses a 1.035x multiplier. Then it's 1.040x, in Sample 7 it's 1.051x, and in Sample 8 it's 1.06 The multipliers are 1x for Sample 9, 1.081x for Sample 9, and 1.131x for Sample 10. Furthermore, as shown in Table 1, the number of cobalt atoms contained in tricobalt tetroxide is proportional to the amount of magnesium oxide. The number of magnesium atoms contained in um is 0.010 times. Also, from Table 1, tritroxide The number of fluorine atoms contained in lithium fluoride is 0.020 times the number of cobalt atoms contained in cobalt. It is 0.020 times.

[0289] Regarding the above 10 samples, in the same manner as the production method described in Embodiment 1, the starting materials were mixed, first heating was performed, after cooling, crushing treatment was performed, second heating was performed, and after cooling, recovery was carried out to obtain cathode active material particles from Sample 1 to Sample 10. As the first heating condition, treatment was performed at 1000 °C for 10 hours in a dry air atmosphere. As the second heating condition, treatment was performed at 800 °C for 2 hours in a dry air atmosphere.

[0290] <SEM Observation> For each of the obtained samples, observation was carried out using a scanning electron microscope (SEM: Scanning Electron Microscope). The observation results of Sample 1 and Sample 4 are shown in FIGS. 22(A) and (B), the observation results of Sample 7 and Sample 8 are shown in FIGS. 23(A) and (B), and the observation results of Sample 9 and Sample 10 are shown in FIGS. 24(A) and (B), respectively. As Li / Co increases, it can be seen that the particles become larger. In Sample 4, many particles with a particle size of about 5 μm are observed, while in Sample 8, many particles with a particle size of about 20 μm are observed, and in Sample 10, particles with a particle size exceeding 50 μm are observed.

[0291] <Particle Size Distribution> Next, among the obtained samples, for Sample 1 to Sample 4 and for Sample 6 to Sample​​It was carried out. For the measurement, a laser diffraction particle size distribution analyzer (SALD-2200 type, manufactured by Shimadzu Corporation ) was used. The measurement results from Sample 1 to Sample 4 and from Sample 6 to Sample 10 are shown in Fig. 25. Fig. 25(A) shows the results of Sample 1 to 4 and Sample 6, and Fig. 25(B) shows the results from Sample 7 to Sample 10, respectively. In Fig. 25, the vertical axis represents the relative intensity and the horizontal axis represents the particle size .

[0292] Also, in Fig. 26, on the horizontal axis, the value obtained by dividing the sum of the number of lithium atoms contained in each of lithium carbonate and lithium fluoride by the number of cobalt atoms contained in cobalt tetroxide ((Li / C o)_R) is shown, and on the vertical axis, the peak value of the relative intensity, here the particle size at which the relative intensity becomes the maximum value, is shown.

[0293] As (Li / Co)_R increased, the peak value of the particle size tended to increase. Also, a tendency was observed that the increase in the peak value became steep when the value of (Li / Co)_R was near 1.05.

Example

[0294] In this example, XPS analysis was performed on Samples 1 to 10 obtained in Example 1.

[0295] <XPS analysis> The composition obtained by XPS analysis is shown in Table 2.

[0296]

Table 2

[0297] ​​​The atomic ratios obtained by XPS for each sample are shown in Figures 27, 28, and 29. Figure 27 shows the ratio of lithium to cobalt (Li / Co), and Figure 28 shows the ratio of lithium to cobalt. Figure 29 shows the ratio of magnesium to cobalt (Mg / Co), and the ratio of fluorine to cobalt (F / C). Figures o) are shown below. Figures 28 and 29 show the process for producing positive electrode active material particles. Therefore, before the second heating (white in the diagram) and after the completion of the process, i.e., after the second heating (black in the diagram). The analysis results for color are shown.

[0298] From Figure 27, the Li / Co ratio obtained by XPS for each sample was greater than 0.5. It was less than 0.85. Also, the Li / Co value increased from Sample 8 onwards. A trend was observed. As shown in Figure 28 below, from Sample 8 onwards, the second region 102 It may be thin or barely formed. Occupying the area measured by XPS The proportion of the first region 101 increases, and the Li / Co value in lithium cobalt oxide It is thought that the ratio of lithium to cobalt approached 1.

[0299] Furthermore, as shown in Figure 28, the Mg / Co ratio tended to increase after the second heating process. This suggests that the second heating process further promotes magnesium segregation.

[0300] As shown in Figure 28, Sample 1, Sample 2, and Sample 3 use XPS The Mg / Co ratio obtained was greater than 0.25 and less than 0.3. Also, Samp Samples 4, 5, and 6 show Mg / C obtained by XPS. o was greater than 0.3 and less than 0.4. Also, Sample 8 and Sample In e9, Mg / Co obtained by XPS was 0.1 or less. Also, in Sample 10, Mg was below the detection limit by XPS and was not detected. After Sample 8 where the ratio of starting materials ([Li / Co)_R) is 1.061, the concentration of magnesium is low and the second region 102 may be thin or hardly formed on the surface of the positive electrode active material particles. There is a possibility that it is not formed.

[0301] From FIG. 29, for Samples 1 to 6, F / Co obtained by XPS was greater than 0.05 and less than 0.15. Also, for Samples 8 to Samp le 10, F / Co obtained by XPS was greater than 0.2 and less than 0.3. After Sample 8 where the ratio of starting materials ([Li / Co)_R) is 1.061, the concentration of fluorine tended to be significantly higher. This may also be considered to have increased relatively as the magnesium concentration decreased.

Example

[0302] In this example, cross-sectional TEM observations were performed on Sample 4 and Sample 9 obtained in Example 1.

[0303] <TEM Observation> Each sample was thinned by FIB (Focused Ion Beam System: focused ion beam processing observation device), and then HAADF-STEM images were observed. A JEM-ARM200F manufactured by JEOL Ltd. was used for the observation. The observation results of Sample 4 are shown in FIG. 30(A), and the observation results of Sample 9 are shown in FIG. 30(B).

[0304] ​​​​​​​In Figure 30(A), a second region 102 with a thickness of approximately 1.5 nm is formed on the particle surface. This is achieved. Furthermore, this region has a crystal structure or crystal structure with respect to the first region 101 located inside. This suggests that the orientation is different. On the other hand, in Figure 30(B), layered regions are present on the surface of the particles. This has not been observed to a significant degree.

[0305] In Sample 4, a layered region was formed on the surface, and XPS results showed that this region contained magnesium. Nesium is distributed at relatively high concentrations. On the other hand, in Sample 9, on the surface of the particles... The magnesium concentration was low, and no significant layered regions were observed. [Examples]

[0306] In this example, Samples 1 to 8 obtained in Example 1 were used. We manufactured a coin-type rechargeable battery of the CR2032 type (20mm in diameter, 3.2mm in height). The cycle characteristics were evaluated.

[0307] The positive electrode contains the positive electrode active material particles prepared above, acetylene black (AB), and polyf The positive electrode active material particles are made of vinylidene DF (PVDF): AB:PVDF = 95:2.5:2.5 A slurry mixed in (by weight) was applied to the current collector. From Sample 8 onwards. The positive electrodes used up to Sample 10 underwent a pressing process.

[0308] Lithium metal was used for the counter electrode.

[0309] The electrolyte in the electrolyte solution contains 1 mol / L lithium hexafluoride phosphate (LiPF6). The electrolyte used is ethylene carbonate (EC) and diethyl carbonate (DEC). EC:DEC = 3:7 (volume ratio), vinylene carbonate (VC) is mixed at 2 wt%. I used that.

[0310] The positive electrode and negative electrode cans were made of stainless steel (SUS).

[0311] The measurement temperature for the cycle characteristics test was set to 25°C. The charging was performed with a current density of 6 per unit weight of active material. The test was performed with a constant current of 8.5mA / g (equivalent to approximately 0.3C) and an upper voltage limit of 4.6V, and then the current density was measured. Constant voltage charging was performed until the current reached 1.37 mA / g (equivalent to approximately 0.005 C). Discharge was performed using live materials. Constant current with a current density of 68.5 mA / g per unit weight (equivalent to approximately 0.3 C), lower limit voltage of 2.5 The test was performed using V. Each unit underwent 30 charge-discharge cycles.

[0312] Figure 31(A) shows the use of positive electrode active material particles from Sample 1 to Sample 8. The graph shows the cycle characteristics of the secondary battery. The horizontal axis represents the number of cycles, and the vertical axis represents the energy density. This indicates the maintenance rate. Energy density is the product of discharge capacity and mean discharge voltage. The energy density maintenance rate is calculated by taking the initial discharge capacity or the maximum discharge capacity as 100%. To make the results from Sample 1 to Sample 6 easier to see, the vertical axis has been widened. The resulting diagram is shown in Figure 31(B).

[0313] Compared to Sample 1, Sample 2, and Sample 3, Sample In version 4, the capacity retention rate improved, and in Samples 5 and 6, the capacity retention rate improved even further. The retention rate improved. As the ratio of the starting materials, (Li / Co)_R, increased, the capacity was maintained. The ratio improved, and excellent properties were obtained when (Li / Co)_R was 1.035 or higher. On the other hand, (L In Sample 7, where i / Co)_R exceeds 1.05, the capacity retention rate decreases. The capacity retention rate was even lower compared to Sample 1 through Sample 3. In version 8, the capacity retention rate decreased even further.

[0314] By making (Li / Co)_R less than 1.05, the capacity retention rate can be increased. Furthermore, by increasing the value beyond 1.02, the capacity retention rate could be further improved. [Explanation of symbols]

[0315] 100 Positive electrode active material particles 101 First Domain 102 Second Domain 103 The Third Domain 200 Active material layer 201 Graphene Compounds 211a positive electrode 211b negative electrode 212a Lead 212b Reed 214 Separator 215a Joint 215b Joint 217 Fixing member 250 batteries 251 Exterior 261 Folded section 262 Seal part 263 Seal part 271 Ridge 272 Valley Line 273 Space 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 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 508 Electrolyte 509 Exterior 510 Positive lead electrode 511 Negative lead electrode 600 Secondary battery 601 Positive Electrode Cap 602 Battery Can 603 Positive terminal 604 Positive electrode 605 Separator 606 negative electrode 607 Negative terminal 608 Insulating board 609 Insulating board 610 Gasket 611 PTC element 612 Safety valve mechanism 900 Circuit Boards 910 Labels 911 terminal 912 Circuit 913 Secondary battery 914 Antenna 915 Antenna 916 layers 917 layers 918 Antenna 919 terminal 920 Display device 921 Sensor 922 terminals 930 cabinets 930a enclosure 930b enclosure 931 negative electrode 932 Positive electrode 933 Separator 950 Wound body 951 terminal 952 terminals 980 Secondary battery 993 Wound body 994 negative electrode 995 positive electrode 966 Separator 997 Lead Electrode 998 Lead Electrode 7100 Portable Display Device 7101 enclosure 7102 Display section 7103 Operation Buttons 7104 Secondary battery 7200 Mobile Information Terminal 7201 enclosure 7202 Display section 7203 Band 7204 Buckle 7205 Operation Buttons 7206 Input / output terminal 7207 Icons 7300 display device 7304 Display section 7400 mobile phones 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 7407 Secondary battery 7409 Current collector 7500 e-cigarettes 7501 Atomizer 7502 Cartridge 7504 Secondary battery 8000 display device 8001 enclosure 8002 Display section 8003 Speaker section 8004 Secondary battery 8021 Charging device 8022 Cable 8024 Secondary battery 8100 Lighting device 8101 enclosure 8102 Light source 8103 Secondary battery 8104 Ceiling 8105 Side wall 8106 floor 8107 Window 8200 indoor unit 8201 enclosure 8202 Air outlet 8203 Secondary battery 8204 Outdoor unit 8300 Electric Refrigerator / Freezer 8301 enclosure 8302 Refrigerator door 8303 Freezer door 8304 Secondary battery 8400 automobiles 8401 Headlight 8406 Electric motor 8500 automobiles 8600 Scooter 8601 Side Mirror 8602 Secondary battery 8603 Turn signal light 8604 Under-seat storage 9600 Tablet devices 9625 Switch 9626 Switch 9627 Power switch 9628 Operation switch 9629 Fastener 9630 cabinet 9630a enclosure 9630b enclosure 9631 Display section 9633 Solar Cell 9634 Charge / Discharge Control Circuit 9635 Energy Storage Unit 9636 DC-DC converter 9637 Converter 9640 Moving parts

Claims

1. A method for producing positive electrode active material particles having a first region and a second region, The second region has a region that is in contact with the outside of the first region, The first region comprises lithium, element M, and oxygen. The aforementioned element M is one or more elements selected from cobalt, manganese, and nickel. The second region comprises the element M, oxygen, magnesium, and fluorine. The positive electrode active material particles are formed using a plurality of raw materials, A method for producing positive electrode active material particles in which the ratio (Li / M) of the total number of lithium atoms in the plurality of raw materials to the total number of element M atoms in the plurality of raw materials is greater than 1.02 and less than 1.

05.

2. In claim 1, A method for producing positive electrode active material particles, wherein the number of magnesium atoms in the plurality of raw materials is 0.005 or more and 0.05 or less relative to the total number of element M atoms in the plurality of raw materials.

3. In claim 1 or claim 2, A method for producing positive electrode active material particles, wherein the number of fluorine atoms in the plurality of raw materials is 0.01 or more and 0.1 or less relative to the total number of element M atoms in the plurality of raw materials.

Images