JP2012094352A - Positive electrode plate for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, and method of manufacturing positive electrode plate for nonaqueous electrolyte secondary battery, and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode plate for nonaqueous electrolyte secondary battery having excellent I/O characteristics, and to provide a nonaqueous electrolyte secondary battery, a method of manufacturing a positive electrode plate for nonaqueous electrolyte secondary battery, and a battery pack.SOLUTION: In the positive electrode plate for nonaqueous electrolyte secondary battery having a collector, and an electrode active material layer formed on the surface of the collector at least partially, the electrode active material layer is composed of electrode active material particles, and a metal oxide showing alkali metal ion elimination reaction. The electrode active material particles and the collector are bonded by a metal oxide showing alkali metal ion elimination reaction, and the electrode active material particles are also bonded each other.

Description

  The present invention relates to a positive electrode plate used for a non-aqueous electrolyte secondary battery, a non-aqueous electrolyte secondary battery, a method for producing a positive electrode plate for a non-aqueous electrolyte secondary battery, and a battery pack.

  A non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery has a high energy density and a high voltage, and is gradually charged when the battery is charged before being completely discharged, which is called a memory effect at the time of charge / discharge. Since there is no phenomenon in which the battery capacity decreases, it is used in various fields such as portable devices, notebook computers, and portable devices.

Currently, as a measure to prevent global warming, efforts to reduce CO ₂ emissions are being carried out on a global scale. By reducing the dependence on oil and allowing it to travel with a low environmental load, it can greatly reduce CO ₂ emissions. There is an urgent need to develop and promote next-generation clean energy vehicles represented by plug-in hybrid vehicles and electric vehicles that can contribute. If non-aqueous electrolyte secondary batteries can be used as the driving force for these next-generation clean energy vehicles, there is no need to rely on gasoline, which can greatly contribute to CO ₂ reduction and greatly prevent global warming. Can contribute. On the other hand, in order to use a nonaqueous electrolyte secondary battery as a driving force for a next-generation clean energy vehicle, output characteristics similar to gasoline are required.

  Currently, various proposals of non-aqueous electrolyte secondary batteries include a positive electrode plate, a negative electrode plate, a separator, and a non-aqueous electrolyte solution. The positive electrode plate is generally provided with an electrode active material layer in which positive electrode active material particles are fixed to the surface of a current collector such as a metal foil. The negative electrode plate is generally provided with an electrode active material layer in which negative electrode active material particles such as graphite are fixed on the surface of a current collector such as copper or aluminum.

  In order to manufacture the electrode plate which is the positive electrode plate or the negative electrode plate, first, the electrode active material particles which are the positive electrode active material particles or the negative electrode active material particles, the resin binder, or further, the conductive material or other materials as necessary. The material is kneaded and / or dispersed in a solvent to prepare a slurry-like electrode active material layer forming liquid. And an electrode plate provided with an electrode active material layer is formed by applying an electrode active material layer forming liquid on the current collector surface, then drying to form a coating film on the current collector, and pressing (for example, Patent Document 1 or Patent Document 2).

  At this time, the electrode active material particles contained in the electrode active material layer forming liquid are particulate metal compounds dispersed in the liquid, and as such, are applied to the surface of the current collector, dried, and pressed. Even if it is done, it will be hard to adhere to the surface of the current collector, and will peel off from the current collector immediately. Therefore, when forming the electrode active material layer, a resin binder is added to the electrode active material layer forming liquid, and the electrode active material particles are fixed on the current collector by the resin binder, and the electrode active material particles They are stuck together.

JP 2006-310010 A JP 2006-107750 A

  However, when the electrode active material layer is formed by the method proposed in Patent Document 1 and Patent Document 2, the impedance is lowered to a level that can satisfy the requirements in the field where high input / output characteristics are required. I can't.

  When charging the battery, if a voltage is applied to the positive electrode, the positive electrode is deficient in electrons, and the negative electrode is sent through an external circuit. At that time, alkali metal atoms in the positive electrode active material are deprived of electrons and become alkali metal ions. Next, the alkali metal ions are attracted to the negative electrode through the electrolytic solution. Since the positive electrode continues to be deficient in electrons, the stored alkali metal atoms are deprived of electrons and new alkali metal ions are generated. Then, alkali metal ions move to the negative electrode again. The alkali metal ions that have moved to the negative electrode are given electrons on the negative electrode surface, return to the original electrically neutral alkali metal atoms, and are stored in the negative electrode. During discharge, alkali metal atoms in the negative electrode are ionized to generate alkali metal ions, and these alkali metal ions move to the positive electrode through the electrolytic solution, get electrons from the positive electrode, return to the alkali metal atom, and are stored in the positive electrode active material. The

  In addition, in a general non-aqueous electrolyte secondary battery in which graphite or the like is used for the negative electrode as described above, the solvent or solute (alkaline) contained in the non-aqueous electrolyte during the initial charge (during initial charge). Metal ions) and the negative electrode active material react to form a SEI (Solid Electrolyte Interface) film on the surface of the negative electrode. The SEI film thus formed prevents the negative electrode active material from reducing the non-aqueous electrolyte.

  However, the formation of this SEI film consumes not only the solvent contained in the non-aqueous electrolyte but also alkali metal ions that are attracted to the negative electrode through the non-aqueous electrolyte in the reaction. And the alkali metal ion consumed for formation of a SEI film cannot contribute to subsequent charging / discharging reaction, and initial stage charging / discharging efficiency will fall.

  The present invention was made in view of such a situation, and in the positive electrode plate for a non-aqueous electrolyte secondary battery, an object is to provide a positive electrode plate having excellent input / output characteristics and initial charge / discharge efficiency, Also, by using such a positive electrode plate, it is possible to realize a non-aqueous electrolyte secondary battery excellent in initial charge / discharge efficiency, a method for manufacturing such a positive electrode plate, and input / output characteristics and initial It aims at providing a battery pack provided with the nonaqueous electrolyte secondary battery excellent in charging / discharging efficiency.

  The present invention for solving the above problems is a positive electrode plate for a non-aqueous electrolyte secondary battery comprising a current collector and an electrode active material layer formed on at least a part of the surface of the current collector. The electrode active material layer contains electrode active material particles and a metal oxide exhibiting an alkali metal ion desorption reaction, and the electrode active material particles, the current collector, and the electrode active material particles The metal oxides are fixed to each other, and an alkali metal ion emission potential of the metal oxide is lower than an alkali metal ion emission potential of the electrode active material particles.

  The metal oxide may be a lithium composite oxide. The metal oxide may be a composite oxide of lithium and at least one metal selected from cobalt, nickel, manganese, iron, and titanium.

  In addition, the electrode active material layer may include a portion where adjacent metal oxides exhibiting an alkali metal ion desorption reaction are connected by a continuous crystal lattice.

  In addition, the present invention for solving the above-described problems is provided with at least a positive electrode plate, a negative electrode plate, a separator provided between the positive electrode plate and the negative electrode plate, and an electrolyte solution containing a nonaqueous solvent. A water electrolyte secondary battery, wherein the positive electrode plate is a positive electrode plate for a non-aqueous electrolyte secondary battery having the above characteristics.

  In addition, the method of the present invention for solving the above-mentioned problems is that the electrode active material particles are heated and have a lower alkali metal ion release potential than the electrode active material particles and exhibit an alkali metal ion desorption reaction. An application step of applying an electrode active material layer forming liquid containing one or more metal element-containing compounds to be a metal oxide to at least a part of the current collector to form a coating film; And a heating step of heating the coating film at a temperature equal to or higher than a temperature at which the metal element-containing compound becomes the electrode active material.

  In addition, as the metal element-containing compound, one or more metal salts containing a metal selected from cobalt, nickel, manganese, iron, and titanium, and a lithium salt may be used.

  Further, the present invention for solving the above-described problems includes at least a storage case, a nonaqueous electrolyte secondary battery including a positive electrode terminal and a negative electrode terminal, and a protection circuit having an overcharge and overdischarge protection function, In a battery pack configured by storing the non-aqueous electrolyte secondary battery and the protection circuit in a storage case, the non-aqueous electrolyte secondary battery is a non-aqueous electrolyte secondary battery having the above characteristics. It is characterized by that.

  The positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention (hereinafter, also simply referred to as “electrode plate”) is an alkali metal ion desorption reaction between electrode active material particles, a current collector, and electrode active material particles. It is fixed by the metal oxide shown. Thereby, the impedance of the positive electrode plate can be lowered, and the input / output characteristics can be improved. Further, in addition to the above-described effects, this metal oxide has a lower alkali metal ion emission potential than the electrode active material particles. Therefore, at the time of initial charge, alkali metal ions are first released from the metal oxide, and these alkali metal ions are consumed for forming the SEI film. Therefore, since the alkali metal ions released from the electrode active material particles are not consumed at all for the formation of the SEI coating, it is possible to improve the initial charge / discharge efficiency.

  Moreover, according to the nonaqueous electrolyte secondary battery of the present invention, it is possible to provide a nonaqueous electrolyte secondary battery having input / output characteristics and initial charge / discharge efficiency.

  In addition, according to the method for producing a positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention (hereinafter, also simply referred to as “the production method of the present invention”), an easy method and a general-purpose material, the input / output characteristics, In addition, a positive electrode plate for a non-aqueous electrolyte secondary battery that can improve the initial charge / discharge efficiency can be manufactured.

  Moreover, according to the battery pack of this invention, the battery pack with which said effect was achieved can be provided.

It is sectional drawing of the positive electrode plate for nonaqueous electrolyte secondary batteries of this invention. It is a cyclic voltammogram which shows the result of the cyclic voltammetry test using the metal oxide which shows alkali metal ion insertion elimination reaction. It is a cyclic voltammogram which shows the result of the cyclic voltammetry test using the metal oxide which does not show alkali metal ion insertion elimination reaction. It is the schematic which shows an example of the nonaqueous electrolyte secondary battery of this invention. It is a sectional exploded view showing an example of a battery pack of the present invention.

  Hereinafter, the positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention will be specifically described with reference to FIGS. 1A and 1B are sectional views of a positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention. In the following description, a lithium ion secondary battery will be described as an example of the non-aqueous electrolyte secondary battery of the present invention unless otherwise specified.

(Positive electrode plate for non-aqueous electrolyte secondary battery)
As shown in FIGS. 1 (a) and 1 (b), a positive electrode plate 10 for a non-aqueous electrolyte secondary battery of the present invention includes a current collector 1 and electrodes formed on at least a part of the surface of the current collector. The electrode active material layer 2 includes electrode active material particles 21 and a metal oxide 22 that exhibits an alkali metal ion desorption reaction.

(Current collector)
The current collector 1 used in the present invention is not particularly limited as long as it is generally used as a current collector for a positive electrode plate for a nonaqueous electrolyte secondary battery. For example, a current collector formed of a simple substance such as an aluminum foil or a nickel foil or an alloy can be preferably used. The current collector 1 used in the present invention is a current collector that has been subjected to surface processing on the surface on which the electrode active material layer 2 is scheduled to be formed (the surface of the current collector) as necessary. Also good. As the current collector 1 whose surface is processed on its surface, a current collector in which a conductive material is laminated on the surface of a material having a current collecting function, chemical polishing treatment, corona treatment, and oxygen plasma treatment were performed. Examples include current collectors. That is, the current collector 1 of the present invention is not only a current collector formed of only a material having a current collecting function, but also a surface in which a substance for ensuring conductivity is laminated, or some surface treatment Also included are those made. The surface of the current collector in the present invention means the surface of a material having a current collecting function in the current collector 1 formed only from a material having a current collecting function, and has a current collecting function. In the case where surface processing or a conductive material is laminated on the entire surface of the material, the surface processing surface or the surface of the conductive material is referred to. In addition, in the case where a part of the surface of the material having a current collecting function is subjected to a surface processing treatment or a conductive material, the surface processing surface, the surface of the conductive material, or these surfaces A portion where a processing treatment or a conductive substance is not stacked (that is, a surface of a material having a current collecting function).

  Although the thickness of the electrical power collector 1 will not be specifically limited if it is the thickness which can generally be used as an electrical power collector of the positive electrode plate for nonaqueous electrolyte secondary batteries, It is preferable that it is 10-100 micrometers, and is 15-50 micrometers. It is more preferable.

(Electrode active material layer)
The electrode active material layer 2 in the present invention is composed of a metal oxide that exhibits an electrode active material particle 21, a current collector 1, an electrode active material particle 21, and an alkali metal ion desorption reaction for fixing the electrode active material particles 21 to each other. The product 22 is contained.

  The layer thickness of the electrode active material layer 2 is not particularly limited, and can be appropriately designed in consideration of electric capacity and input / output characteristics required for the positive electrode plate, and is generally about 300 nm to 200 μm. In particular, the present invention can meet the demand for higher capacity without increasing the thickness of the electrode active material layer 2 due to the presence of the metal oxide, and can further reduce the thickness of the electrode active material layer 2. Is possible.

  In addition, the electrode active material layer 2 preferably has voids so that the electrolytic solution can permeate, and the porosity is preferably 10% or more and 70% or less.

  Below, the substance contained in the electrode active material layer 2 in this invention is demonstrated concretely.

<Electrode active material particles>
The electrode active material particles 21 have a function as an active material that exhibits an alkali metal ion insertion / release reaction, and an alkali metal ion release potential is higher than that of a metal oxide 22 that exhibits an alkali metal ion insertion / release reaction described later. As long as the condition “high” is satisfied, chargeable / dischargeable electrode active material particles generally used in a positive electrode plate for a nonaqueous electrolyte secondary battery can be appropriately selected and used. For example, specific examples of the electrode active material particles 21 in the lithium ion secondary battery include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFeO ₂ , Li ₄ Ti ₅ O ₁₂ , LiFePO ₄ , LiNi _1/3. Examples thereof include electrode active material particles such as lithium transition metal composite oxides such as Mn _1/3 Co _1/3 O ₂ and LiNi _0.80 Co _0.15 Al _0.05 O ₂ . Specific examples of the electrode active material particles 21 in the sodium ion secondary battery include electrode active material particles such as NaCoO ₂ , NaNi _0.3 Mn _0.7 O ₂ , and NaNi _0.1 Cr _0.9 O ₂ .

  The particle diameter of the electrode active material particles 21 used in the present invention is not particularly limited, and those having an arbitrary size can be appropriately selected and used.

  In addition, the particle diameter of the electrode active material particle 21 shown in the present invention and this specification is an average particle diameter (volume median particle diameter: D50) measured by laser diffraction / scattering particle size distribution measurement. Moreover, the particle diameter of the electrode active material particles 21 contained in the electrode active material layer was obtained from the image of the recognized particles by identifying the data of the measured electron microscope observation results using a particle recognition tool. A particle size distribution graph can be created based on the shape data and calculated from the particle size distribution graph. The particle size distribution graph can be created, for example, by using an image analysis type particle size distribution measurement software (manufactured by Mount Tech Co., Ltd., MAC VIEW) based on an electron microscope observation result.

<Metal oxide showing alkali metal ion elimination reaction>
As shown in FIG. 1, the electrode active material layer 2 constituting the positive electrode plate 10 of the present invention is bound so as to fix the current collector 1, the electrode active material particles 21, and the electrode active material particles to each other. And a metal oxide 22 that exhibits an alkali metal ion elimination reaction that functions as an agent, and the alkali metal ion release potential of the metal oxide 22 is the alkali metal ion of the electrode active material particles 21. It is characterized by being lower than the emission potential. Hereinafter, the metal oxide 22 that exhibits an alkali metal ion desorption reaction may be simply referred to as a metal oxide 22.

  In the present invention, when the electrode active material particles 21 and the current collector 1 and the electrode active material particles 21 are fixed by the metal oxide 22 exhibiting alkali metal ion desorption reaction, the following two Including embodiments. The first fixing mode is between the objects to be fixed (for example, between the electrode active material particles 21 and the current collector 1, between the electrode active material particles 21, or when a conductive material is used). This is an embodiment in which the metal oxide 22 is interposed between the substance particles 21 and between the conductive material particles to fix them together. In the second fixing mode, the objects to be bonded are in direct contact with each other, and the objects to be bonded are fixed to each other by the presence of the metal oxide 22 surrounding the contact portion. In the present invention, in the electrode active material layer, any one of the first fixing mode and the second fixing mode, or both modes are present. In particular, as the particle diameter of the electrode active material particles 21 contained in the electrode active material layer becomes smaller, the second fixing mode tends to increase.

  The metal oxide 22 may be present in the electrode active material layer in such a shape that the objects to be fixed are fixed in the first fixing mode or the second fixing mode. There is no particular limitation on the size and shape. For example, the metal oxide 22 is in the form of fine particles, and a large number of fine particle-like metal oxides 22 are formed on one surface of the electrode active material particles 21 or on the entire surface or a part of the aggregate. May be present so as to surround.

  In particular, as shown in FIG. 1B, the electrode active material layer 2 preferably includes a portion where adjacent crystal oxides 22 are connected by a continuous crystal lattice. With this configuration, the input / output characteristics can be improved. As described above, the metal oxide 22 in the present invention is for fixing the electrode active material particles 21 on the current collector 1, and as shown in FIG. In part, it is presumed that the film adhesion of the electrode active material layer 2 is improved by including the portions connected by the continuous crystal lattices. And it is thought that this improvement in film adhesion contributes to the improvement in the input / output characteristics.

  Further, from the viewpoint of improving the film adhesion of the electrode active material layer 2, it is more desirable that the portion where the crystal lattices of adjacent metal oxides 22 are continuous exist significantly in the electrode active material layer 2. In the present invention, whether or not the crystal lattices of the binding materials are continuous can be confirmed by observing the crystal lattice of the cross section of the adjacent binding materials in the electrode active material layer with a transmission electron microscope. .

  In order to configure the electrode active material layer of the present invention so as to include a portion where crystal lattices in adjacent metal oxides 22 are continuous, the positive electrode plate of the present invention can be manufactured according to the manufacturing method of the present invention described later. desirable. That is, in the production method of the present invention, an electrode active material layer forming liquid is applied onto a current collector to form a coating film, and the electrode active material layer is formed from the coating film by performing means such as heating. . At that time, on the current collector, the metal element-containing compound present around the electrode active material particles undergoes a reaction such as thermal decomposition and oxidation, and the metal oxide which is a binder around the electrode active material particles Is generated. At this time, if a part of the adjacent binding substances (or their precursors) are joined, the crystal growth of both tends to proceed simultaneously at the joined part. As a result of the simultaneous crystal growth in the joint portion, the electrode active material layer of the present invention is configured to include a portion where crystal lattices in adjacent binder materials are continuous.

  Alternatively, the metal oxide 22 may be non-particulate and may be a continuous body that fills the space between the electrode active material particles 21 and the current collector 1 and between the electrode active material particles 21 leaving a gap. Alternatively, the metal oxide 22 may form a continuous coating layer in the form of a film, a pleat, or a hump that surrounds two or more aggregates of the electrode active material particles 21. Further, when the surface of the metal oxide 22 is observed at the level of a scanning electron microscope, for example, the surface is observed in a smooth state, the innumerable protrusions are dense, the one between particles, or these The surface condition is not limited at all. That is, the metal oxide 22 in the present invention surrounds at least a part of the electrode active material particles 21 and the metal oxides 22 are connected to each other or the metal oxide 22 is a continuous body. What is necessary is just to comprise the electrode active material layer 2 by connecting the metal oxide 22 in the vicinity of the current collector 1 to the surface of the current collector 1.

  The metal oxide showing the alkali metal ion elimination reaction that constitutes the positive electrode plate 10 of the present invention has a lower alkali metal ion release potential than the electrode active material particles 21 described above. Therefore, the alkali metal ions released from the electrode active material particles 21 during the initial charging can be improved in the initial charge / discharge efficiency without being consumed for the formation of the SEI film.

  Below, the mechanism which has the said effect is demonstrated more concretely. In the positive electrode plate 10 of the present invention, the current collector 1, the electrode active material particles 21, and the metal oxide 22 for fixing the electrode active material particles 21 to each other are metal oxides 22 that exhibit an alkali metal ion desorption reaction. For this reason, at the time of initial charging, a reaction occurs in which alkali metal ions are released from the electrode active material particles 21 constituting the electrode active material layer 2 and the metal oxide 22 exhibiting an alkali metal ion desorption reaction. Here, according to the present invention, the alkali metal ion release potential of the metal oxide 22 exhibiting this alkali metal ion elimination reaction is lower than the alkali metal ion release potential of the electrode active material particles 21, so As a result, the alkali metal ion desorption reaction in which the current collector 1 and the electrode active material particles 21 and the electrode active material particles 21 are fixed to each other faster than the electrode active material particles 21 release alkali metal ions. The metal oxide 22 releases alkali metal ions.

  As described above, at the time of initial charging, alkali metal ions are consumed to form the SEI film of the negative electrode active material. Therefore, in the present invention, the alkali released from the metal oxide 22 exhibiting an alkali metal ion elimination reaction is used. Metal ions will be consumed for the formation of the SEI film during initial charging. Then, in the positive electrode plate 10 of the present invention, the alkali metal ions released from the electrode active material particles at the time of initial charging are not consumed at all for the formation of the SEI film. For example, the electrode active material layer is formed only from the electrode active material particles 21. It can be considered that the improvement of the initial charge / discharge efficiency was realized as compared with the positive electrode plate.

  That is, in the present invention, the current collector 1, the electrode active material particles 21, and the electrode active material particles 21 exhibit an alkali metal ion desorption reaction and have a lower alkali metal ion release potential than the electrode active material particles 21. By fixing with the metal oxide 22, the input / output characteristics and the initial charge / discharge efficiency are improved.

  In addition, when the alkali metal ion emission potential of the metal oxide 22 is higher than that of the electrode active material particles 21, the alkali metal ions are first released from the electrode active material particles during the initial charge, and the released alkali metal Ions are consumed to form the SEI coating. Then, for example, the initial charge / discharge efficiency is reduced as in the case of the positive electrode plate in which the electrode active material layer is formed only from the electrode active material particles 21, and the improvement of the initial charge / discharge efficiency is realized as in the present invention. I can't think of it.

  As described above, the metal oxide 22 that also functions as a so-called binder material plays a role of releasing alkali metal ions consumed for forming the SEI film before the electrode active material particles 21. The initial charge / discharge efficiency is improved. Therefore, the metal oxide 22 may be any metal oxide that exhibits at least an alkali metal ion elimination reaction, and it is not necessarily defined in the present invention that this metal oxide is a substance that exhibits an alkali metal ion insertion and elimination reaction. Not needed.

  The alkali metal ions released from the metal oxide 22 are consumed for forming the SEI film, but not all the alkali metal ions released from the metal oxide 22 are consumed. That is, once the SEI film is formed by alkali metal ions released from the metal oxide 22, no further alkali metal ions released from the metal oxide are consumed. Here, when the metal oxide 22 exhibits only an alkali metal ion elimination reaction and does not exhibit an alkali metal ion insertion reaction, the alkali metal released from the metal oxide 22 and not consumed for the formation of the SEI film. Ions cannot contribute to the subsequent charge / discharge reaction. Considering such points, it is more preferable that the metal oxide 22 is a metal oxide 22 that exhibits an alkali metal ion insertion / release reaction and exhibits a function as an active material. By employing the metal oxide 22 that exhibits an alkali metal ion insertion reaction in addition to the alkali metal ion desorption reaction, the electric capacity of the positive electrode plate 10 is “the electric capacity of the electrode active material particles 21” + “after the initial charge” The electric capacity of the metal oxide 22 increases.

In addition to the alkali metal ion desorption reaction, as the metal oxide 22 (chargeable / dischargeable metal oxide 22) exhibiting an alkali metal ion insertion reaction, for example, when used for a positive electrode plate for a lithium ion secondary battery, Lithium composite oxide can be used. Among them, LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFeO ₂ , Li ₄ Ti, which are complex oxides of at least one metal selected from cobalt, nickel, manganese, iron, and titanium and lithium. Lithium transition metal composite oxides such as ₅ O ₁₂ , LiFePO ₄ , LiNi _1/3 Mn _1/3 Co _1/3 O ₂ and LiNi _0.80 Co _0.15 Al _0.05 O ₂ can be preferably used. In the present invention, the metal oxide 22 is a metal oxide having a higher alkali metal ion emission potential than at least the electrode active material particles 21, and depends on the electrode active material particles 21 used. The usable metal oxides 22 are different. In the present invention, the metal oxide exhibiting an alkali metal ion desorption reaction naturally includes a metal oxide exhibiting an alkali metal ion insertion desorption reaction.

  In the present invention, the alkali metal ion release potential of the electrode active material particles 21 and the metal oxide 22 means a potential at which oxidation corresponding to an alkali metal ion desorption reaction starts. The alkali metal ion emission potential can be confirmed by an electrochemical measurement (cyclic voltammetry: CV) method. The electrochemical measurement (cyclic voltammetry: CV) method refers to an appropriate voltage range (for example, A1 (V) to A2 (V)) of the electrode active material from A1 (V) at a scanning speed of 1 mV / sec. In this test, the operation of sweeping back to A2 (V) and then returning to A1 (V) is repeated three times to confirm the presence or absence of an alkali metal ion insertion / release reaction. In addition, an appropriate voltage range means the voltage range which can confirm the presence or absence of the peak which shows the insertion-release reaction of the alkali metal ion used for a test in a cyclic voltammetry test.

Specifically, the case where the electrode active material particles 21 and the metal oxide 22 are LiMn ₂ O ₄ will be described as an example, and the alkali metal ion (lithium ion) emission potential will be described. When the electrode active material particles 21 and the metal oxide 22 are LiMn ₂ O ₄ , after sweeping from a suitable voltage range of 3.0 V to 4.3 V at a scanning speed of 1 mV / second, the voltage is again 3.0 V. Repeat the work to return to about 3 times. At this time, as shown in FIG. 2, oxidation corresponding to an alkali metal ion (lithium ion) elimination reaction of LiMn ₂ O ₄ starts from about 3.75 V, and an oxidation peak appears at about 3.9 V. A reduction peak corresponding to an alkali metal ion (lithium ion) insertion reaction appears in the vicinity of 1 V, and the presence or absence of an alkali metal ion insertion and desorption reaction can be confirmed. Since the alkali metal ion release potential in the present invention is a potential at which oxidation corresponding to an alkali metal ion elimination reaction starts, 3.75 V is the alkali metal ion release potential when the active material is LiMn ₂ O _4. It becomes. Similarly, the alkali metal ion emission potential can be confirmed for other active materials.

The alkali metal ion release potential of the metal oxide calculated according to the above method is shown below.
Li ₄ Ti ₅ O ₁₂・ ・ ・ 1.3V
LiFeO ₂ ... 3.0V
LiFePO ₄ ... 3.1V
LiNi _0.80 Co _0.15 Al _0.05 O ₂ ... 3.3V
LiNiO ₂ 3.5V
LiCoO ₂ ... 3.6V
LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ... 3.65V
LiMn ₂ O ₄ ... 3.75V

  Based on the magnitude of the alkali metal ion emission potential, the combination of the electrode active material particles and the metal oxide exhibiting alkali metal ion insertion / release reaction can be determined. Specifically, if the electrode active material particle 21 is selected and a metal oxide having a lithium release potential lower than that of the selected electrode active material particle is selected as the metal oxide exhibiting alkali metal ion insertion / release reaction, Good.

  In addition, as the metal oxide 22 constituting the positive electrode plate of the present invention, (1) an alkali metal ion desorption reaction is exhibited even if it is other than the materials listed above, and (2) the current collector 1 and The electrode active material particles 21 and the electrode active material particles 21 can be fixed to each other, and (3) further satisfy the three conditions that the alkali metal ion emission potential is lower than that of the electrode active material particles 21 Any material may be used, and the material is not limited to the materials listed above. For example, Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Fr, Ra, As a metal oxide 22 of the present invention, one metal oxide of a metal element such as Ce or Ce or a composite metal oxide containing two or more metal elements that satisfies the above three conditions Can be used.

  Further, the metal oxide 22 may be an amorphous metal oxide 22 or a crystalline metal oxide 22. Note that an amorphous metal oxide means a case where a metal oxide or a sample containing the metal oxide is analyzed by an X-ray diffractometer and a peak of the metal oxide is not detected. A crystalline metal oxide means a case where a metal oxide or a sample containing the metal oxide is analyzed by an X-ray diffractometer and a peak of the metal oxide is detected.

  Further, it is not necessary that all the metal oxides 22 contained in the electrode active material layer 2 contribute to the adhesion between the current collector 1 and the electrode active material particles 21 and the adhesion between the electrode active material particles 21. . For example, the metal oxide 22 fixed to the electrode active material particles 21 may be present so as not to be fixed to the current collector 1 or the electrode active material particles 21.

(Mixing ratio)
In the present invention, the mixing ratio of the electrode active material particles 21 and the metal oxide 22 contained in the electrode active material layer 2 is not particularly limited, and the type and size of the electrode active material particles 21 used are not limited. It can be determined as appropriate in consideration of the functions required of the metal oxide 22.

  On the other hand, when the content of the metal oxide 22 acting as a binder is too small, the adhesion force between the current collector 1 and the electrode active material particles 22 and the electrode active material particles 22 is increased to a desired level. May be impossible. Therefore, considering this point, when the mass ratio of the electrode active material particles 21 is 100 parts by mass, the mass ratio of the metal oxide 22 is preferably 1 part by mass or more and 100 parts by mass or less.

  In addition, the present invention does not prohibit the use of a resin binder as a so-called binder, and the resin binder and the metal oxide 22 are used in combination. May be fixed. In the case of using a resin binder and the metal oxide 22 together as a so-called binder, the total mass of the binder (total mass of the resin binder + total mass of the metal oxide 22) As the proportion of the metal oxide 22 increases, the input / output characteristics improve and the capacity of the entire battery also increases. Considering such points, the ratio of the metal oxide 22 to the total mass of the so-called binder is preferably in the range of 50 to 100% by mass. Of course, even if it is outside this range, it goes without saying that the input / output characteristics are improved as much as the metal oxide 22 is contained. Further, when the metal oxide 22 is a metal oxide that exhibits an alkali metal ion insertion / release reaction, the overall battery capacity is increased by this amount.

  In addition, whether or not the metal oxide contained in the electrode active material layer exhibits an alkali metal ion desorption reaction can be confirmed by the CV method described above. That is, it is possible to estimate what kind of metal oxide is contained in the sample by cutting the electrode active material layer to prepare a sample and performing composition analysis of the sample. Whether or not the metal oxide exhibits an alkali metal ion desorption reaction by forming a film made of the estimated metal oxide on a substrate such as glass and subjecting it to a cyclic voltammetry test. Can be confirmed. Specifically, when the metal oxide 22 exhibits an alkali metal ion elimination reaction, an oxidation peak corresponding to the elimination reaction appears as shown in FIG. On the other hand, in a metal oxide that does not show an alkali metal ion elimination reaction, as shown in FIG. 3, an oxidation peak corresponding to the elimination reaction does not appear.

(Other materials)
The electrode active material layer 2 may be composed of only the electrode active material particles 21 and the metal oxide 22, but may be formed by adding further additives without departing from the spirit of the present invention. . For example, according to the present invention, good conductivity can be exhibited without using a conductive material exemplified by a conductive carbon material such as carbon black, but better conductivity is desired. Depending on the case or the type of active material particles, a conductive material may be used.

(Method for producing positive electrode plate for non-aqueous electrolyte secondary battery)
Next, a method for producing a positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention (hereinafter sometimes simply referred to as “the production method of the present invention”) will be described. The production method of the present invention includes electrode active material particles, and one or two that become a metal oxide that has a lower alkali metal ion release potential than an electrode active material particle and exhibits an alkali metal ion elimination reaction when heated. A coating process formed by applying an electrode active material layer forming liquid containing at least a part of the metal element-containing compound to at least a part of the current collector to form a coating film, and a coating film formed by the coating process And a heating step of heating at or above the temperature at which the metal element-containing compound becomes a metal oxide.

  According to the manufacturing method of the present invention, the above-described positive electrode plate of the present invention can be manufactured with high yield. This will be specifically described below.

(Coating process)
The coating step includes one or more electrode active material particles and a metal oxide that has a lower alkali metal ion release potential than that of the electrode active material particles and that exhibits an alkali metal ion desorption reaction when heated. In this step, the electrode active material layer forming liquid containing the metal element-containing compound is applied to at least a part of the current collector to form a coating film.

<Preparation of electrode active material layer forming solution>
The electrode active material particles used for the preparation of the electrode active material layer forming liquid can be the same as the electrode active material particles described above, and the description thereof is omitted here. In addition, in the manufacturing method of this invention, it is the same as the above-mentioned that the particle diameter of the electrode active material particle used can select a desired magnitude | size.

  Further, in the electrode active material layer forming liquid, one or two kinds that become a metal oxide that has an alkali metal ion release potential lower than that of the electrode active material particles and exhibits an alkali metal ion elimination reaction when heated. The above metal element-containing compound is added.

  The metal element-containing compound is a precursor of a metal oxide that exhibits a function as a so-called binder that fixes the electrode active material particles and the current collector and the electrode active material particles to each other. Therefore, it is possible to generate a metal oxide having a lower alkali metal ion emission potential than the electrode active material particles by being applied on the substrate in a state of being added to the electrode active material layer forming liquid and heated. Any metal element-containing compound may be used.

  Whether or not the metal oxide produced from the binder precursor to be used exhibits an alkali metal ion elimination reaction is determined by applying a solution containing a metal element-containing compound on a substrate in a preliminary experiment. By heating, a binding substance is formed and can be confirmed by the cyclic voltammetry method described above.

  As the metal element-containing compound, a lithium element-containing compound and one or more metal element-containing compounds containing any metal element selected from cobalt, nickel, manganese, iron or titanium are preferably used. Can do. The metal element-containing compound may be an inorganic metal element-containing compound in which no carbon is contained in the compound, or an organometallic element-containing compound constituted by containing carbon in the compound. Also good. In the present invention and the present specification, the inorganic metal element-containing compound and the organic metal-containing compound may be simply referred to as a metal element-containing compound.

  Examples of the metal element-containing compound include chloride, nitrate, sulfate, perchlorate, acetate, phosphate, bromate and the like of other metal elements such as lithium element or cobalt. Among them, in the present invention, chloride, nitrate, and acetate are preferably used because they are easily available as general-purpose products. In particular, nitrate is preferably used because it has good film forming properties for a wide variety of current collectors.

For example, as the metal element-containing compound for generating LiCoO ₂ as a metal oxide for fixing the current collector, the electrode active material particles, and the electrode active material particles, a Li element-containing compound and a Co element-containing compound Can be used in combination as a main raw material, and other raw materials can be used in combination as required. Examples of the Li element-containing compound include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate. Examples of the compound include cobalt (II) chloride hexahydrate, cobalt (II) formate dihydrate, cobalt (III) acetylacetonate, cobalt (II) acetylacetonate dihydrate, cobalt acetate (II ) Tetrahydrate, cobalt (II) oxalate dihydrate, cobalt (II) nitrate hexahydrate, cobalt (II) ammonium chloride hexahydrate, sodium cobalt (III) nitrite, and cobalt sulfate ( II) The heptahydrate etc. are mentioned. The combination ratio (Li: Co = X: 1) of the Li element-containing compound and the Co element-containing compound used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.

Further, for example, as a metal element-containing compound for generating LiNiO ₂ as a metal oxide for fixing the current collector and the electrode active material particles, and the electrode active material particles, the Li element-containing compound and the Ni element-containing compound A compound can be used in combination as a main raw material, and further, other raw materials can be used in combination as required. Examples of the Li element-containing compound are the same as in the case of producing LiCoO ₂ described above. Examples of the Ni element-containing compound include nickel chloride (II) hexahydrate and nickel acetate (II) tetrahydrate. , Nickel (II) perchlorate hexahydrate, nickel (II) bromide trihydrate, nickel (II) nitrate hexahydrate, nickel (II) acetylacetonate dihydrate, hypophosphorous acid Examples thereof include nickel (II) acid hexahydrate and nickel (II) sulfate hexahydrate. The combination ratio (Li: Ni = X: 1) of the Li element-containing compound and Ni element-containing compound used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.

Further, for example, as a metal element-containing compound for producing LiMn ₂ O ₄ as a metal oxide for fixing the current collector, the electrode active material particles, and the electrode active material particles, a Li element-containing compound, and Mn Element-containing compounds can be used in combination as main raw materials, and other raw materials can be used in combination as required. Examples of the Li element-containing compound are the same as in the case of producing LiCoO ₂ described above, and examples of the Mn element-containing compound include manganese acetate (III) dihydrate and manganese nitrate (II) hexahydrate. Products, manganese (II) sulfate pentahydrate, manganese (II) oxalate dihydrate, manganese (III) acetylacetonate, and the like. The combination ratio (Li: Mn = X: 1) of the Li element-containing compound and the Mn element-containing compound used as the main raw material is not particularly limited, but is preferably 0.5 ≦ X <1, 0.5 ≦ More preferably, X ≦ 0.6.

Further, for example, as a metal element-containing compound for generating LiFeO ₂ as a metal oxide for fixing the current collector and the electrode active material particles, and the electrode active material particles, the Li element-containing compound and the Fe element-containing compound A compound can be used in combination as a main raw material, and further, other raw materials can be used in combination as required. Examples of the Li element-containing compound are the same as in the case of producing LiCoO ₂ described above. Examples of the Fe element-containing compound include iron (II) chloride tetrahydrate, iron (III) citrate, and acetic acid. Examples include iron (II), iron (II) oxalate dihydrate, iron (III) nitrate nonahydrate, iron (II) lactate trihydrate, and iron (II) sulfate heptahydrate. . The combination ratio (Li: Fe = X: 1) of the Li element-containing compound and the Fe element-containing compound used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.

Further, for example, as a metal element-containing compound for producing Li ₄ Ti ₅ O ₁₂ as a metal oxide for fixing the current collector and the electrode active material particles and the electrode active material particles, a Li element-containing compound, In addition, the Ti element-containing compound can be used in combination as a main raw material, and other raw materials can be used in combination as required. Examples of the Li element-containing compound are the same as in the case of producing LiCoO ₂ described above, and examples of the Ti element-containing compound include titanium tetrachloride and titanium acetylacetonate. The combination ratio (Li: Ti = X: 1) of the Li element-containing compound and the Ti element-containing compound used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, preferably 1 ≦ X ≦ 1. 2 is more preferable.

  In the electrode active material layer forming liquid described above, the ratio of the total amount of one or more metal element-containing compounds added in the solvent is 0.01 to 5 mol / L, particularly 0.1 to 5 mol / L. 2 mol / L is preferred. By setting the concentration to 0.01 mol / L or more, the current collector and the electrode active material layer generated on the current collector surface can be satisfactorily adhered, and the active material particles can be fixed. In addition, by setting the concentration to 5 mol / L or less, it is possible to maintain a good viscosity enough to apply the electrode active material layer forming liquid to the current collector surface, and to form a uniform coating film. can do.

  Further, the electrode active material layer forming liquid may be blended with a conductive material, an organic substance that is a viscosity adjusting agent of the electrode active material layer forming liquid, or other additives within the scope of the present invention. Good. The solvent for dissolving the metal element-containing compound may be any solvent that can dissolve the metal element-containing compound, and a conventionally known solvent can be appropriately selected and used. For example, water, lower alcohols such as NMP (N-methyl-2-pyrrolidone), methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, 2-butanol, t-butanol, acetylacetone, diacetyl And ketones such as benzoylacetone, ketoesters such as ethyl acetoacetate, ethyl pyruvate, ethyl benzoylacetate and ethyl benzoylformate, toluene, ethylene glycol, diethylene glycol, polyethylene glycol, and mixed solvents thereof.

  The method for applying the electrode active material layer forming liquid onto the current collector is not particularly limited, and a general application method can be appropriately selected and used. For example, the electrode active material layer forming liquid can be applied to any region of the current collector surface by printing, spin coating, dip coating, bar coating, spray coating, or the like. In addition, when the surface of the current collector is porous, has a large number of irregularities, or has a three-dimensional structure, it can be manually applied in addition to the above method. Note that the current collector used in the present invention can further improve the film-forming property of the electrode active material layer by performing corona treatment, oxygen plasma treatment, or the like in advance as necessary.

  Moreover, although there is no limitation in particular about the application quantity of an electrode active material layer formation liquid, it is preferable to apply | coat in the range that the thickness after a heating becomes the thickness of the electrode active material layer demonstrated above.

(Heating process)
The heating step is a step of heating the coating film formed in the coating step described above to evaporate the solvent and generating a metal oxide from the metal element-containing compound.

  By the heating step, the current collector, the electrode active material particles, and the electrode active material particles are fixed by a metal oxide having a lower alkali metal ion release potential than the electrode active material particles.

  About the heating temperature in a heating process, what is necessary is just the temperature which can produce | generate a metal oxide from the metal element containing compound used, Therefore Therefore, it can set suitably according to these kind. Specifically, for example, the metal oxide can be generated by heating at a temperature equal to or higher than the temperature at which the metal element-containing compound is thermally decomposed.

  For example, the heating method is not particularly limited as long as it is a heating method or a heating apparatus that can heat the coating film at a temperature at which the metal element-containing compound is thermally decomposed. For example, a method of using any one of a hot plate, an oven, a heating furnace, an infrared heater, a halogen heater, a hot air blower, etc., or a combination of two or more can be mentioned.

  Further, the heating atmosphere in the heating step is not particularly limited, and can be appropriately determined in consideration of the material used for manufacturing the positive electrode plate, the heating temperature, the oxygen potential of the metal element, and the like. For example, an air atmosphere is preferable in that a special atmosphere adjustment is not necessary and the heating process can be easily performed. In particular, when an aluminum foil is used as the current collector, the heating step can be preferably performed because there is no possibility that the aluminum foil is oxidized even if the heating step is performed in an air atmosphere.

  On the other hand, when copper foil is used as the current collector, it is not desirable because it is oxidized when the heating step is performed in an air atmosphere. Therefore, in such a case, it is preferable to heat in an inert gas atmosphere, a reducing gas atmosphere, or a mixed gas atmosphere of an inert gas and a reducing gas. In the case where the heating step is performed in an atmosphere that does not contain sufficient oxygen gas, when an electrode active material made of a metal oxide is generated in the electrode active material layer, the metal element in the metal element-containing compound Oxidation needs to be realized by combining oxygen and metal element in the compound contained in the electrode active material layer forming liquid, so it is necessary to use a compound containing oxygen element in the compound to be used There is.

  In the production method of the present invention, the inert gas atmosphere or the reducing gas atmosphere is not particularly limited to a specific atmosphere, and the production method of the present invention can be appropriately carried out under these conventionally known atmospheres. Examples of the inert gas atmosphere include argon gas, nitrogen gas, and reducing gas atmosphere, such as hydrogen gas, carbon monoxide gas, or a gas atmosphere in which the inert gas and the reducing gas are mixed.

(Non-aqueous electrolyte secondary battery)
Next, the nonaqueous electrolyte secondary battery of the present invention will be described with reference to FIG. FIG. 4 is a schematic diagram showing an example of the non-aqueous electrolyte secondary battery 100 of the present invention. As shown in FIG. 4, a nonaqueous electrolyte secondary battery 100 of the present invention is combined with a positive electrode plate 10 in which an electrode active material layer 2 is provided on one surface side of a current collector 1 and this. The current collector 55 includes a negative electrode plate 50 having an electrode active material layer 54 provided on one surface side thereof, and a separator 70 provided between the positive electrode plate 10 and the negative electrode plate 50. The container is housed in a container constituted by 82 and sealed in a state in which the nonaqueous electrolytic solution 90 is filled in the container.

  Here, the non-aqueous electrolyte secondary battery of the present invention is characterized in that the positive electrode plate 10 for a non-aqueous electrolyte secondary battery described above is used as an essential configuration as a positive electrode plate. The non-aqueous electrolyte secondary battery of the present invention is not particularly limited with respect to other requirements as long as it satisfies this requirement, and a conventionally known negative electrode plate, non-aqueous electrolyte, and container may be appropriately selected and used. It is possible, and is not limited to the form shown in FIG. In addition, about the positive electrode plate for nonaqueous electrolyte secondary batteries of this invention, it is as having demonstrated above, and detailed description is abbreviate | omitted.

(Positive electrode plate)
The non-aqueous electrolyte secondary battery of the present invention is characterized by using the above-described positive electrode plate of the present invention as the positive electrode plate. As described above, the positive electrode plate of the present invention does not collapse the crystal structure of the electrode active material particles 21 even when charged in an overcharged state. Never happen. Moreover, the input / output characteristics are high, and the battery capacity is also high. Therefore, by using such a positive electrode plate, the performance of the positive electrode plate is exhibited also in the non-aqueous electrolyte secondary battery of the present invention.

(Negative electrode plate)
As the negative electrode plate, a conventionally known negative electrode plate for a non-aqueous electrolyte secondary battery can be appropriately selected and used. Generally, as a conventionally known negative electrode plate, a copper foil such as an electrolytic copper foil or a rolled copper foil having a thickness of about 5 to 50 μm is used as a current collector, and the negative electrode plate is formed on at least a part of the current collector surface. The electrode active material layer forming solution is applied, dried, and pressed as necessary. The electrode active material layer forming liquid in the negative electrode plate generally includes an active material made of a carbonaceous material such as natural graphite, artificial graphite, amorphous carbon, carbon black, or a material obtained by adding a different element to these components, Alternatively, negative electrode active material particles such as metal oxides such as Li ₄ Ti ₅ O ₁₂ , metal lithium and its alloys, tin, silicon, and alloys thereof, materials capable of occluding and releasing alkali metal ions, and resin binders In general, other additives such as a conductive material are dispersed and mixed as necessary. However, the present invention is not limited to this.

(Non-aqueous electrolyte)
The non-aqueous electrolyte 90 used in the present invention is not particularly limited as long as it is generally used as a non-aqueous electrolyte for a non-aqueous electrolyte secondary battery, but when used for a lithium ion secondary battery. For this, a nonaqueous electrolytic solution in which a lithium salt is dissolved in an organic solvent is preferably used.

Examples of the lithium salt include inorganic lithium salts such as LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiCl, and LiBr; LiB (C ₆ H ₅ ) ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiC ( Organic compounds such as SO ₂ CF ₃ ) ₃ , LiOSO ₂ CF ₃ , LiOSO ₂ C ₂ F ₅ , LiOSO ₂ C ₄ F ₉ , LiOSO ₂ C ₅ F ₁₁ , LiOSO ₂ C ₆ F ₁₃ , and LiOSO ₂ C ₇ F ₁₅ Typical examples include lithium salts.

  Examples of the organic solvent used for dissolving the lithium salt include cyclic esters, chain esters, cyclic ethers, and chain ethers.

  As a structure of the battery manufactured using the positive electrode plate, the negative electrode plate, the separator, and the nonaqueous electrolytic solution, a conventionally known structure can be appropriately selected and used. For example, the structure which winds a positive electrode plate and a negative electrode plate in the shape of a spiral via the separator like a polyethylene porous film, and accommodates in a battery container is mentioned. As another aspect, a structure in which a positive electrode plate and a negative electrode plate cut into a predetermined shape are stacked and fixed via a separator, and this is housed in a battery container may be employed. In any structure, after the positive electrode plate and the negative electrode plate are stored in the battery container, the lead wire attached to the positive electrode plate is connected to the positive electrode terminal provided in the outer container, while the lead wire attached to the negative electrode plate Is connected to a negative electrode terminal provided in the outer container, and the battery container is further filled with a nonaqueous electrolyte and then sealed to produce a nonaqueous electrolyte secondary battery.

(Battery pack)
Next, a battery pack 200 configured using the nonaqueous electrolyte secondary battery 100 of the present invention will be described with reference to FIG. FIG. 5 is a schematic exploded view showing an example of the battery pack 200 of the present invention.

  As shown in FIG. 5, the battery pack 200 is configured by storing the nonaqueous electrolyte secondary battery 100 in a resin container 36 a, a resin container 36 b, and an end case 37. Further, a protection circuit for preventing overcharge and overdischarge between one end face of the nonaqueous electrolyte secondary battery, which is a face including the positive electrode terminal 32 and the negative electrode terminal 33, and the end case 37. A substrate 34 is provided.

  The protection circuit board 34 includes an external connection connector 35. The external connection connector 35 is connected to an external connection window 38a provided in the resin container 36a and an external connection window 38b provided in the end case 37. Inserted and connected to external terminals. The protection circuit board 34 is mounted with a charge / discharge safety circuit (not shown) for controlling charge / discharge, a wiring circuit for connecting the external connection terminal and the nonaqueous electrolyte secondary battery 100, and the like. .

  As the battery pack 200, a configuration of a conventionally known battery pack can be appropriately selected except that the nonaqueous electrolyte secondary battery 100 using the positive electrode plate 10 of the present invention is used. Although not shown, the battery pack 200 includes a positive electrode lead plate connected to the positive electrode terminal 32, a negative electrode lead plate connected to the negative electrode terminal 33, and an insulator between the nonaqueous electrolyte secondary ground 100 and the end case 37. Etc. may be provided as appropriate.

  In addition, the nonaqueous electrolyte secondary battery 100 of the present invention using the positive electrode plate 10 of the present invention is not limited to the usage mode for the battery pack, and further functions such as blocking of excessive current, battery temperature monitoring, etc. And the protection circuit may be used by being integrated with the non-aqueous electrolyte secondary battery. In such an embodiment, the battery pack can be used as a secondary battery having a protection function and a protection circuit without constituting a battery pack, and is highly versatile. In addition, some aspects demonstrated above are only illustrations, and do not limit the use of the positive electrode plate 10 of this invention, or the nonaqueous electrolyte secondary battery 100 of this invention at all.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. Hereinafter, unless otherwise specified, parts or% is based on mass.

Example 1
Li (CH ₃ COO) · 2H ₂ O [molecular weight: 102.02]: 5 g added to pure water: 5 g and Ti (Oi-C ₃ H ₇ ) ₂ (C ₆ H ₁₄ O ₃ ) ₂ : 16 g was mixed to prepare a raw material liquid for producing a lithium composite oxide showing lithium ion insertion / release reaction. Next, 10 g of the above raw material liquid, positive electrode active material LiMn ₂ O ₄ : 10 g having an average particle diameter of 4 μm, 1.2 g of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Black), carbon fiber (manufactured by Showa Denko KK) (VGCF) 0.25 g, silane coupling agent (KBM403): 2 g, resin hydroxyethyl cellulose: 0.2 g of a thickener aqueous solution in which 9.8 g was dissolved in 9.8 g, and a solvent (methanol) were mixed, An electrode active material layer forming solution was prepared by kneading with an Excel auto homogenizer (Nippon Seiki Seisakusho Co., Ltd.) at a rotational speed of 8000 rpm for 15 minutes.

Next, an aluminum plate having a thickness of 15 μm was prepared as a current collector, and the electrode active material layer forming liquid prepared above was prepared in such an amount that the electrode mass of the electrode active material layer finally obtained was 46 g / m ² . An electrode active material layer-forming coating film was formed on one side of the current collector with an applicator. Subsequently, the coating film was pressed using a roll press machine (manufactured by Sank Metal Co., Ltd .: mechanical type 1 ton) under the conditions of applied pressure: 0.1 ton / cm and pressing speed of 10 mm / second. Thereafter, the current collector with the electrode active material layer-forming coating film formed thereon was placed in a normal temperature electric furnace (muffle furnace, Denken, P90) and heated from room temperature to 450 ° C. over 20 minutes. Thus, a positive electrode plate for a non-aqueous electrolyte secondary battery in which a positive electrode active material layer was laminated on the current collector was obtained. And after taking out the said positive electrode plate from an electric furnace and leaving it to room temperature, it cut | judged to the predetermined | prescribed magnitude | size (disk 15 mm in diameter) using the press, and this was made into the positive electrode plate of Example 1. FIG. In addition, it was 24 micrometers when the thickness of the electrode active material layer of Example 1 was measured 10 points | pieces using the micrometer, and the average value was computed.

(Example 2)
The raw material liquid of Example 1 was Li (CH ₃ COO) · 2H ₂ O [molecular weight: 102.02]: 10 g, Co (NO ₃ ) ₂ · 6H ₂ O [molecular weight: 290.9]: 30 g, Methanol: Changed to a raw material solution mixed with 20 g, 8 g of this raw material solution is used, and the electrode active material layer finally obtained has an electrode mass of 65 g / m ^2, and the current collector The positive electrode plate of Example 2 was prepared in the same manner as in Example 1 except that the electrode active material layer forming solution prepared above was applied to one side of the substrate with an applicator to form an electrode active material layer forming coating film. Obtained. The thickness of the electrode active material layer was measured using a micrometer, and the thickness of the electrode active material of Example 2 was measured at 10 points using a micrometer, and the average value was calculated to be 34 μm. Met.

(Example 3)
A positive electrode plate of Example 1 was immersed in an immersion tank filled with a resin mixture prepared by using PVDF resin as a resin material and mixing with an NMP solvent so that the concentration of PVDF was 0.1%. The resin mixture was sufficiently permeated into the voids of the layer. Then, the positive electrode plate of Example 1 was taken out from the said immersion layer, was installed in the oven heated at 150 degreeC, and was dried for 15 minutes, and the solvent of the resin liquid mixture was removed. Thus, a positive electrode plate of Example 3 in which the resin binder remained in the electrode active material layer was obtained. In addition, it was 25 micrometers when the thickness of the electrode active material layer of Example 3 was measured 10 points | pieces using the micrometer, and the average value was computed.

Example 4
The positive electrode plate of Example 1 was immersed in an immersion tank filled with a resin mixture prepared by using PVDF resin as a resin material and mixing with an NMP solvent so that the concentration of PVDF was 5%. The resin mixture was sufficiently permeated into the voids. Then, the positive electrode plate of Example 1 was taken out from the said immersion layer, was installed in the oven heated at 150 degreeC, and was dried for 15 minutes, and the solvent of the resin liquid mixture was removed. Thus, a positive electrode plate of Example 4 in which the resin binder remained in the electrode active material layer was obtained. In addition, it was 25 micrometers when the thickness of the electrode active material layer of Example 4 was measured 10 points | pieces in arbitrary places using the micrometer, and the average value was computed.

(Comparative Example 1)
LiMn ₂ O ₄ powder having an average particle size of 4 μm as a raw material of the positive electrode active material: 10 g, acetylene black (Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.): 1.2 g as a conductive material, and PVDF (manufactured by Kureha Co., Ltd., as a binder) KF # 1320): 0.9 g of organic solvent NMP (manufactured by Mitsubishi Chemical Corporation): PVDF resin solution dissolved in 10 g is dispersed, and Excel Auto Homogenizer (Nippon Seiki Seisakusho Co., Ltd.) for 15 minutes at a rotation speed of 8000 rpm. The slurry was stirred to prepare a slurry-like electrode active material layer forming liquid.

Next, an aluminum plate having a thickness of 15 μm was prepared as a current collector, and the electrode active material layer forming liquid prepared above was applied so that the electrode mass of the electrode active material layer finally obtained was 82 g / m ^2. Then, it was dried in an air atmosphere at 120 ° C. for 20 minutes using an oven to form a coating film for forming an electrode active material layer. Subsequently, it cut | judged to the predetermined | prescribed magnitude | size (disc 15mm in diameter) using a press, and was vacuum-dried at 120 degreeC for 12 hours, and the positive electrode plate of the comparative example 1 was obtained. In addition, the thickness of the electrode active material layer was measured using a micrometer, and the thickness of the electrode active material layer of Comparative Example 1 was measured at 10 points using a micrometer, and the average value was calculated. However, it was 48 μm.

(Comparative Example 2)
Li (CH ₃ COO) · 2H ₂ O [molecular weight: 102.02]: 2 g, Mn (CH ₃ COO) ₂ · 4H ₂ O [molecular weight: 245.09]: 9 g, and methanol: 11 g Were mixed to obtain a raw material solution for producing a lithium composite oxide exhibiting lithium ion insertion / release reaction. Next, 6.5 g of the above raw material liquid, 10 g of a positive electrode active material LiCoO having an average particle diameter of 8 μm, 1.2 g of acetylene black (manufactured by Denki Kagaku Co., Ltd., Denka Black), carbon fiber (manufactured by Showa Denko KK, VGCF) ) 0.25 g, silane coupling agent (KBM403): 2 g, resin hydroxyethyl cellulose: 10 g of thickener aqueous solution in which 0.2 g of pure water was dissolved in 9.8 g, and a solvent (methanol) were mixed, and Excel An electrode active material layer forming solution was prepared by kneading with an autohomogenizer (Nippon Seiki Seisakusho Co., Ltd.) at a rotational speed of 8000 rpm for 15 minutes.

Next, an aluminum plate having a thickness of 15 μm is prepared as a current collector, and the electrode active material layer forming liquid prepared above is used in an amount such that the electrode mass of the electrode active material layer finally obtained is 50 g / m ² . An electrode active material layer-forming coating film was formed on one side of the current collector with an applicator. Subsequently, the coating film was pressed using a roll press machine (manufactured by Sank Metal Co., Ltd .: mechanical type 1 ton) under the conditions of applied pressure: 0.1 ton / cm and pressing speed of 10 mm / second. Thereafter, the current collector with the electrode active material layer forming coating film formed thereon was placed in a normal temperature electric furnace (muffle furnace, manufactured by Denken, P90) and heated from room temperature to 450 ° C. over 60 minutes. Thus, a positive electrode plate for a non-aqueous electrolyte secondary battery in which a positive electrode active material layer was laminated on the current collector was obtained. And after taking out the said positive electrode plate from an electric furnace and leaving it to room temperature, it cut | judged to the predetermined | prescribed magnitude | size (a 15 mm diameter disc) using the press machine, and this was made into the positive electrode plate of the comparative example 2. In addition, it was 29 micrometers when the thickness of the electrode active material layer of the comparative example 2 was measured 10 points | pieces in arbitrary places using the micrometer, and the average value was computed.

(Battery characteristics evaluation)
<Production of tripolar coin cell>
Lithium hexafluorophosphate (LiPF ₆ ) is added as a solute to a mixed solvent of ethylene carbonate (EC) / dimethyl carbonate (DMC) (volume ratio = 1: 1), and the concentration of LiPF _{6 as} the solute is 1 mol. The non-aqueous electrolyte was prepared by adjusting the concentration to be / L. Using the examples and comparative examples prepared as described above as the positive electrode plate as the working electrode, the metal lithium plate as the counter electrode plate and the reference electrode plate, the non-aqueous electrolyte prepared above as the electrolyte, The assembly was subjected to the following charge / discharge test.

(Initial charging test)
The test cell was charged with a constant current (1000 μA) under a 25 ° C. environment until the voltage reached 4.2 V. After the voltage reached 4.2 V, the voltage did not exceed 4.2 V. As described above, the current (discharge rate: 1C) was decreased until it became 5% or less, and the battery was charged at a constant voltage, fully charged, and then rested for 10 minutes. Here, the “1C” means a current value (current value reaching a discharge end voltage) at which constant current discharge is performed using the tripolar coin cell and discharge is completed in one hour.

(Initial discharge test)
Thereafter, the fully charged test cell was subjected to constant current (1000 μA) (discharge rate: 1 C) until the voltage changed from 4.2 V (full charge voltage) to 3.0 V (discharge end voltage) in an environment of 25 ° C. ), The cell voltage (V) on the vertical axis and the discharge time (h) on the horizontal axis, a discharge curve is created, and the initial discharge capacity (μAh) of the positive electrode plates of the examples and comparative examples is obtained. It was.

(Calculation of initial charge / discharge efficiency (%))
Initial charge / discharge efficiency% = {(initial charge capacity) / (initial discharge capacity)} × 100 Table 1 shows the results of the above-described examples and comparative examples.

<Measurement of DC resistance value>
In the case where the discharge test was performed under the condition of a discharge rate of 1 C using the test cells of the example and the comparative example, the voltage value (V1) (mV) 10 seconds after the start of the discharge was measured. Furthermore, the voltage value (V10) (mV) 10 seconds after the start of discharge was also measured when the discharge test was performed under the condition of the discharge rate 10C. Then, based on these measured values (V1, V10) and the constant current values (I1, I10) (mA) corresponding to the discharge rates 1C, 10C, the direct current resistance value (Ω) is calculated by the following equation 1. It was measured. The measurement results of the DC resistance value (Ω) are also shown in Table 1.

  As can be seen from the above table, each of the positive electrode plates of Examples 1 to 4 of the present invention has a lower alkali metal ion release potential of the metal oxide than the alkali metal ion release potential of the electrode active material particles. Compared to Comparative Example 1 in which no metal oxide is used and Comparative Example 2 in which the lithium release potential of the metal oxide is higher than the alkali metal ion release potential of the electrode active material particles, the initial charge / discharge efficiency is improved. confirmed.

  Moreover, Examples 1-4 were low in direct-current resistance value compared with the comparative example 1 which does not use a metal oxide, and it was confirmed that the effect excellent also in the input-output characteristic is acquired.

DESCRIPTION OF SYMBOLS 1,55 ... Current collector 2,54 ... Electrode active material layer 10 ... Positive electrode plate for non-aqueous electrolyte secondary battery 21 ... Electrode active material particle 22 ... Metal oxide 32. ··· Positive terminal 33 ··· Negative electrode 34 ··· Protection circuit board 35 ··· External connector 36a and 36b · Resin container 37 · · · End case 38a and 38b · · · External connection window 50 · .... Negative electrode plate 70 ... Separator 81, 82 ... Exterior 90 ... Non-aqueous electrolyte 100 ... Non-aqueous electrolyte secondary battery 200 ... Battery pack

Claims (8)

A positive electrode plate for a non-aqueous electrolyte secondary battery comprising a current collector and an electrode active material layer formed on at least a part of the surface of the current collector,
The electrode active material layer contains electrode active material particles and a metal oxide exhibiting an alkali metal ion desorption reaction,
The electrode active material particles and the current collector, and the electrode active material particles are fixed by the metal oxide,
A positive electrode plate for a non-aqueous electrolyte secondary battery, wherein an alkali metal ion emission potential of the metal oxide is lower than an alkali metal ion emission potential of the electrode active material particles.   The positive electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, wherein the metal oxide is a lithium composite oxide.   The metal oxide is a composite oxide of at least one metal selected from cobalt, nickel, manganese, iron, and titanium, and lithium. Positive electrode plate for non-aqueous electrolyte secondary battery.   The said electrode active material layer contains the location where the crystal lattice continues in a part of metal oxide which shows the said alkali metal ion detachment | desorption reaction adjacent, The 1 thru | or 3 characterized by the above-mentioned. The positive electrode plate for nonaqueous electrolyte secondary batteries of any one of these. A non-aqueous electrolyte secondary battery comprising at least a positive electrode plate, a negative electrode plate, a separator provided between the positive electrode plate and the negative electrode plate, and an electrolyte containing a non-aqueous solvent,
The said positive electrode plate is a positive electrode plate for nonaqueous electrolyte secondary batteries of any one of Claims 1 thru | or 4, The nonaqueous electrolyte secondary battery characterized by the above-mentioned. Electrode active material particles, containing one or more metal elements that are heated to have a lower alkali metal ion release potential than the electrode active material particles and become a metal oxide exhibiting an alkali metal ion desorption reaction An application step of applying an electrode active material layer forming liquid containing the compound to at least a part of the current collector to form a coating film;
A method for producing a positive electrode plate for a non-aqueous electrolyte secondary battery, comprising heating the coating film at a temperature equal to or higher than a temperature at which the metal element-containing compound becomes the metal oxide.   7. The metal element-containing compound according to claim 6, wherein at least one metal salt containing a metal selected from cobalt, nickel, manganese, iron, and titanium and a lithium salt are used. The manufacturing method of the positive electrode plate for non-aqueous-electrolyte secondary batteries of description. A storage case; a non-aqueous electrolyte secondary battery including a positive electrode terminal and a negative electrode terminal; and a protection circuit having an overcharge and over-discharge protection function, wherein the storage case includes the non-aqueous electrolyte secondary battery and the In a battery pack configured to contain a protection circuit,
The battery pack, wherein the non-aqueous electrolyte secondary battery is the non-aqueous electrolyte secondary battery according to claim 5.

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