JP2012094403A - Nonaqueous electrolyte secondary battery, and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery showing excellent battery characteristics and a high level of safety even under high-temperature environments.SOLUTION: A positive electrode active material layer contains positive electrode active material particles and a first binder comprising a metallic oxide, and a negative electrode active material layer contains negative electrode active material particles and a second binder comprising a metal or a metallic oxide. The positive electrode active material particles and a positive electrode collector, and the positive electrode active material particles are bound together by the first binder, and the negative electrode active material particles and a negative electrode collector, and the negative electrode active material particles are bound together by the second binder. A separator contains a heat-resistant nitrogen-containing aromatic polymer and ceramic powder.

Description

  The present invention relates to 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 non-aqueous electrolyte secondary battery as a driving force for a next-generation clean energy vehicle, it is necessary to improve output characteristics.

  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. In general, the negative electrode plate includes an electrode active material layer in which graphite or the like is fixed as negative electrode active material particles on the surface of a current collector such as copper or aluminum.

  In order to produce the electrode plate that is the positive electrode plate or the negative electrode plate, first, the electrode active material particles that are the positive electrode active material particles or the negative electrode active material particles, the resin binder, or, further, the conductive material and others as necessary A slurry-like electrode active material layer forming liquid is prepared by kneading and / or dispersing in a solvent. Then, the electrode active material layer forming liquid is applied to the surface of the current collector, then dried to form a coating film on the current collector, and pressed to form an electrode plate having the electrode active material layer (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 is a particulate metal compound dispersed in the liquid, and as such, is coated on the surface of the current collector and dried. Even if it is pressed, it is difficult to adhere to the surface of the current collector, and it 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 with the resin binder, and the electrode The active material particles are fixed to each other.

JP 2006-310010 A JP 2006-107750 A

  However, in the electrode plate formed by the method proposed in Patent Document 1 and Patent Document 2, the electrode active material particles, the current collector, and the electrode active material particles are fixed with a resin binder. There is a problem that the impedance of the electrode active material layer becomes large, and the battery characteristics (for example, output characteristics) cannot be improved.

  In order to solve such problems, all or part of the resin binder is replaced with a metal oxide, that is, an attempt to fix the electrode active material particles, the current collector, and the electrode active material particles to each other with the metal oxide. Has been made. By using a metal oxide instead of the resin binder, the impedance of the electrode active material layer can be reduced by the amount of the metal oxide, thereby improving battery characteristics.

  Moreover, there is also an advantage that the non-aqueous electrolyte secondary battery can be used in a high temperature environment by replacing all or part of the resin binder with a metal oxide. On the other hand, a general separator used for a non-aqueous electrolyte secondary battery loses its function as a separator when used in a high temperature environment, and the positive electrode and the negative electrode are short-circuited (so-called thermal runaway), which is the worst. In this case, since there is a risk of ignition or explosion, it was still difficult to use in a high temperature environment simply by improving the electrode active material layer.

  The present invention has been made in view of such circumstances, and provides a non-aqueous electrolyte secondary battery that has excellent battery characteristics and high safety even when used in a high temperature environment. And it aims at providing the battery pack which show | plays the effect of this nonaqueous electrolyte secondary battery.

  The present invention for solving the above problems includes a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, a negative electrode plate having a negative electrode active material layer on a negative electrode current collector, the positive electrode plate and the negative electrode plate, A non-aqueous electrolyte secondary battery comprising at least a separator provided between and an electrolyte solution containing a non-aqueous solvent, wherein the positive electrode active material layer includes a positive electrode active material particle and a metal oxide. 1, and the negative electrode active material layer contains negative electrode active material particles and a second binder made of metal or metal oxide, and the positive electrode The active material particles, the positive electrode current collector, and the positive electrode active material particles are fixed to each other by the first binding material, and the negative electrode active material particles, the negative electrode current collector, and the negative electrode active material The substance particles are fixed to each other by the second binding substance, and the separator Motor, characterized in that it comprises a heat-resistant nitrogen-containing aromatic polymer and a ceramic powder.

  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.

  According to the non-aqueous electrolyte secondary battery of the present invention, the battery characteristics and safety are excellent even when used in a high temperature environment.

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

It is the schematic which shows an example of the nonaqueous electrolyte secondary battery of this invention. 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 a sectional exploded view showing an example of a battery pack of the present invention.

(Non-aqueous electrolyte secondary battery)
Hereinafter, the non-aqueous electrolyte secondary battery of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing an example of the non-aqueous electrolyte secondary battery 100 of the present invention.

  As shown in FIG. 1, a non-aqueous electrolyte secondary battery 100 of the present invention includes a positive electrode plate 10 in which a positive electrode active material layer 2 is provided on one side of a positive electrode current collector 1, and a combination thereof. A negative electrode plate 50 in which a negative electrode active material layer 54 is provided on one side of the negative electrode current collector 55 and a separator 70 provided between the positive electrode plate 10 and the negative electrode plate 50. The container is housed in a container composed of 81 and 82 and sealed in a state where the container is filled with a nonaqueous electrolytic solution 90. Here, in the non-aqueous electrolyte secondary battery 100 of the present invention, the positive electrode active material layer 2 contains positive electrode active material particles and a first binding material made of metal oxide, The material particles, the positive electrode current collector, and the positive electrode active material particles are fixed to each other by the first binding material, and the negative electrode active material layer 54 is composed of the negative electrode active material particles and the metal or the metal oxide. The negative electrode active material particles, the negative electrode current collector 55, and the negative electrode active material particles are fixed to each other by the second binder material. Furthermore, the non-aqueous electrolyte secondary battery 100 of the present invention is characterized in that the separator 70 includes a heat-resistant nitrogen-containing aromatic polymer and ceramic powder. Hereinafter, a specific configuration of the nonaqueous electrolyte secondary battery 100 of the present invention will be described. In the following description, a lithium ion secondary battery will be described as an example of the nonaqueous electrolyte secondary battery 100 of the present invention unless otherwise specified.

<< Positive electrode plate >>
Next, the positive electrode plate 10 constituting the nonaqueous electrolyte secondary battery 100 of the present invention will be described with reference to FIG. 2A and 2B are cross-sectional views of the positive electrode plate for a non-aqueous electrolyte secondary battery of the present invention.

  As shown in FIGS. 2A and 2B, the positive electrode plate 10 includes a positive electrode current collector 1 and a positive electrode active material layer 2 formed on the positive electrode current collector 1, and a positive electrode active material layer 2. Contains positive electrode active material particles 21 and a first binding material 22 made of a metal oxide. The positive electrode active material particles 21, the positive electrode current collector 1, and the positive electrode active material particles 21 are fixed to each other by a first binding material 22 made of this metal oxide. Hereinafter, the positive electrode current collector 1 and the positive electrode active material layer 2 will be described more specifically.

<Positive electrode current collector>
The positive electrode current collector 1 used in the present invention is not particularly limited as long as it is generally used as a positive electrode current collector of a positive electrode plate for a nonaqueous electrolyte secondary battery. For example, a positive electrode current collector formed of a simple substance such as an aluminum foil or a nickel foil or an alloy can be preferably used. Note that the positive electrode current collector 1 used for the positive electrode plate 10 is subjected to surface processing on the surface on which the positive electrode active material layer 2 is scheduled to be formed (the surface of the positive electrode current collector 1) as necessary. Body 1 may be sufficient. As the positive electrode current collector 1 whose surface is processed on the surface, a positive electrode current collector in which a conductive substance is laminated on the surface of a material having a current collecting function, chemical polishing treatment, corona treatment, oxygen plasma treatment are used. Examples thereof include a positive electrode current collector made. That is, the positive electrode current collector 1 has not only a current collector formed of only a material having a current collecting function, but also a surface on which a substance for ensuring conductivity is laminated, or some surface treatment. Also included are those made.

<Positive electrode active material layer>
The positive electrode active material layer 2 includes a positive electrode active material particle 21, a positive electrode current collector 1, a positive electrode active material particle 21, and a first binder material 22 made of a metal oxide for fixing the positive electrode active material particles 21 to each other. Containing.

  The layer thickness of the positive electrode active material layer 2 is not particularly limited, and is generally about 300 nm to 200 μm. In particular, in the present invention, the presence of the metal oxide 22 can improve the rate characteristics, and the thickness of the positive electrode active material layer 2 can be further increased.

  Moreover, it is preferable that the positive electrode active material layer 2 has voids to such an extent that the nonaqueous electrolyte solution can permeate, and the porosity is preferably 10% or more and 70% or less. The porosity can be measured with Autopore IV 9500 manufactured by Shimadzu Corporation. Hereinafter, the positive electrode active material particles 21 and the metal oxide 22 will be specifically described.

(Positive electrode active material particles)
The positive electrode active material particles 21 can be appropriately selected and used as chargeable / dischargeable positive electrode active material particles, and the positive electrode active material particles 21 are not particularly limited. Examples of the positive 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 Mn _1/3 Co. Examples thereof include lithium transition metal composite oxides such as _1/3 O ₂ and LiNi _0.80 Co _0.15 Al _0.05 O ₂ .

Among these positive electrode active material particles 21, LiMn ₂ O ₄ can be used particularly preferably. Since LiMn ₂ O ₄ has particularly high rate characteristics among various positive electrode active materials, the rate characteristics are further improved in combination with the fixation by the metal oxide, which is a feature of the present invention, and charge / discharge is achieved. Can be accelerated.

  The particle diameter of the positive electrode active material particles 21 is not particularly limited, and those having an arbitrary size can be appropriately selected and used. However, as the particle diameter of the positive electrode active material particles is smaller, the surface area per unit weight can be increased and the rate characteristics can be improved. Therefore, when higher rate characteristics are required, the positive electrode active material particles 21 have a small particle size, specifically less than 10 μm, preferably 5 μm or less, particularly preferably 1 μm or less.

  In addition, the particle diameters of the positive electrode active material particles 21 shown in the present invention and the present specification and the negative electrode active material particles described later are average particle diameters (volume-median particle diameter: measured by laser diffraction / scattering particle size distribution measurement). D50). The particle diameters of the positive electrode active material particles and the negative electrode active material particles are obtained by identifying the measured electron microscope observation data using a particle recognition tool and obtaining the shape data obtained from the recognized particle image. And a particle size distribution graph can be prepared 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.

(First binding substance)
As shown in FIG. 2, the positive electrode active material layer 2 constituting the positive electrode plate 10 contains a first binder material 22 made of a metal oxide, and the positive electrode current collector 1 and the positive electrode active material particles 21. , And the positive electrode active material particles 21 are fixed to each other by the first binding material 22. Hereinafter, the first binding substance made of a metal oxide may be simply referred to as “first binding substance”.

  As the first binding material, any positive electrode current collector 1, positive electrode active material particles 21, and any metal oxide 22 capable of fixing the positive electrode active material particles 21 to each other can be appropriately selected and used.

As such a metal oxide 22, a metal element generally understood as a metal, 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, Ce, etc., and one or more metals selected from Co, Ni, Mn, Fe, and Ti And a complex oxide with Li, for example, LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFeO ₂ , Li ₄ Ti ₅ O ₁₂ , LiFePO ₄ , LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , _{LiNi 0.9 Co 0.1 O 2, LiNi} 0.80 Co 0.15 Al 0.05 O 2 And the like lithium transition metal composite oxide such.

  The first binder 22 may be a metal oxide that does not exhibit an alkali metal ion insertion / release reaction, or may be a metal oxide that exhibits an alkali metal ion insertion / release reaction. When the first binding material 22 contained in the positive electrode active material layer 2 is a metal oxide that does not exhibit an alkali metal ion insertion / release reaction, the alkali metal ions and the first binding material are Since it does not react electrochemically, the first binder substance 22 in the positive electrode active material layer 2 does not generate an expansion or reactant due to the electrochemical reaction of the first binder substance. There is an advantage that deterioration due to expansion, deficiency, etc. can be suppressed. On the other hand, when the first binding material 22 contained in the positive electrode active material layer 2 is a metal oxide exhibiting an alkali metal ion insertion / release reaction, the first binding material 22 itself is also Since it can function as an active material, there is an advantage that the capacity of the positive electrode plate 10 can be increased.

The presence or absence of an alkali metal ion insertion / elimination reaction of the first binder 22 can be confirmed by an electrochemical measurement (cyclic voltammetry: CV) method. The CV test will be described below. For example, when the electrode potential is within an appropriate voltage range of the active material, for example, lithium ions are assumed as alkali metal ions, and the first binding material 22 is LiMn ₂ O ₄ , the voltage is swept from 3.0 V to 4.3 V. After that, the operation of returning to 3.0 V again is repeated about three times. The scanning speed is preferably 1 mV / second. For example, in the case of LiMn ₂ O ₄ , as shown in FIG. 3, an oxidation peak corresponding to an alkali metal ion desorption reaction of LiMn ₂ O ₄ appears in the vicinity of about 3.9 V, and an alkali metal in the vicinity of about 4.1 V. A reduction peak corresponding to the ion insertion reaction appears, whereby the presence or absence of an alkali metal ion insertion / desorption reaction can be confirmed. Further, as shown in FIG. 4, when no peak appears, it can be determined that there is no alkali metal ion insertion / desorption reaction.

  In the present invention, when the positive electrode active material particles 21, the positive electrode current collector 1, and the positive electrode active material particles 21 are fixed by the first binder 22, the following two aspects are included. The first fixing mode is between the adherends (for example, between the positive electrode active material particles 21 and the positive electrode current collector 1, between the positive electrode active material particles 21, or when using a conductive material, the conductive material and the positive electrode. In this mode, the first binder 22 is interposed between the active material particles 21 and the conductive material particles, and the like 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 first binding substance 22 surrounding the contact portion. In the present invention, in the positive electrode active material layer, either one of the first fixing mode and the second fixing mode, or both modes are present. In particular, as the particle diameter of the positive electrode active material particles 21 contained in the positive electrode active material layer becomes smaller, the second fixing mode tends to increase.

  The first binder 22 only needs to be present in the positive electrode active material layer in a shape that fixes the objects to be bonded in the first fixing mode or the second fixing mode. The size and shape of the binding material 22 are not particularly limited. For example, the first binding material 22 is a fine particulate metal oxide, and a number of fine particulate first binding materials 22 are one of the positive electrode active material particles 21 or 2. It may exist so as to surround the entire surface or a part of one or more aggregates.

  In particular, as shown in FIG. 2B, the positive electrode active material layer 2 includes a portion where the crystal lattices are connected in a part of the adjacent first binder materials 22. Is preferred. With this configuration, film adhesion can be improved and rate characteristics can be improved. As described above, the first binding material 22 in the present invention is for fixing the positive electrode active material particles 21 on the positive electrode current collector 1, and as shown in FIG. It is presumed that the film adhesion of the positive electrode active material layer 2 is improved by including at least a part of the binder materials 22 connected by crystal lattices that are continuous with each other. And it seems that this improvement in film adhesion contributes to the improvement in rate characteristics.

  Further, from the viewpoint of improving the film adhesion of the positive electrode active material layer 2, the portion where the crystal lattices of the adjacent first binder materials 22 are continuous may be significantly present in the positive electrode active material layer 2. More desirable. In the present invention, whether or not the crystal lattices of the first binding materials are continuous is determined by observing the crystal lattice in the cross section of the adjacent first binding materials in the positive electrode active material layer with a transmission electron microscope. Can be confirmed.

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

  Further, the first binder 22 is a non-particulate continuous material that fills the space between the positive electrode active material particles 21 and the positive electrode current collector 1 and between the positive electrode active material particles 21 leaving a void. May be. Alternatively, the first binding material 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 positive electrode active material particles 21. Further, the surface of the first binding material 22 is observed in a smooth state when observed at the scanning electron microscope level, for example, in which numerous protrusions are densely packed, or in which there are particles. Or a combination thereof, and the surface state is not limited at all. That is, the first binding material 22 in the present invention surrounds at least a part of the positive electrode active material particles 21 and the first binding materials 22 are connected to each other, or the first binding material 22 is a continuous body. In addition, the first binding material 22 in the vicinity of the positive electrode current collector 1 in the first binding material 22 is connected to the surface of the positive electrode current collector 1 to form the positive electrode active material layer 2. Anything is acceptable.

  In addition, the present invention does not prohibit the use of a resin binder as a so-called binder material, and the resin binder and the first binder material 22 are used in combination, whereby the positive electrode current collector 1 is used. The positive electrode active material particles 21 and the positive electrode active material particles 21 may be fixed to each other. When the resin binder and the first binder 22 are used together, the first binder 22 is based on the total mass of the resin binder and the total mass of the first binder 22. The rate characteristics improve as the proportion of the increases. Considering such points, the ratio of the first binder 22 to the total mass of the resin binder and the first binder 22 may be in the range of 50 to 100% by mass. preferable. Of course, even if it is outside the range, it goes without saying that the rate characteristics are improved by the amount of the first binder 22 contained.

  Further, in the present invention, the mixing ratio of the positive electrode active material particles 21 and the first binding material 22 contained in the positive electrode active material layer 2 is not particularly limited, but the first binding material 22 is not limited. If the content of is too small, the positive electrode current collector 1, the positive electrode active material particles 21, and the positive electrode active material particles 21 may not be able to increase the fixing force to a desired level, and the rate characteristics may be improved. There is a possibility that it cannot be satisfactorily satisfied. Therefore, in consideration of this point, the mass ratio of the first binding material 22 is preferably 1 part by mass or more and 100 parts by mass or less when the mass ratio of the positive electrode active material particles 21 is 100 parts by mass. .

  Further, the positive electrode active material layer 2 may be composed of only the positive electrode active material particles 21 and the first binder material 22, but further additives are included without departing from the spirit of the present invention. It may be formed. 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 manufacturing positive electrode plate)
As described above, the positive electrode plate 10 is provided with the positive electrode active material layer 2 on the positive electrode current collector 1, and the positive electrode active material layer 2 includes the positive electrode active material particles 21 and the first metal oxide. The positive electrode current collector 1, the positive electrode active material particles 21, and the positive electrode active material particles 21 are fixed to each other by containing the binder material 22 and the first binder material 22. If it can take such a structure, there will be no limitation in particular about the manufacturing method of the positive electrode plate 10, However, In this invention, the positive electrode plate mentioned above can be manufactured with a sufficient yield with the following method. Hereinafter, a preferable manufacturing method will be specifically described.

  A preferable manufacturing method of the positive electrode plate 10 described above includes a coating process and a heating process. Hereinafter, each step will be described.

(Coating process)
The coating step includes the positive electrode active material particles 21 described above and one or more metal element-containing compounds that are heated to form a metal oxide (first binding material 22). In this step, the positive electrode active material layer forming liquid is applied to at least a part of the positive electrode current collector 1 to form a coating film.

  The metal element-containing compound is a precursor of a metal oxide (first binding material 22) that fixes the positive electrode active material particles 21, the positive electrode current collector 1, and the positive electrode active material particles 21 to each other. Therefore, any metal element-containing compound capable of becoming a metal oxide (first binding material 22) when coated on a substrate in a state of being added to the positive electrode active material layer forming liquid and heated. It may be.

  Examples of the metal element-containing compound include one or more of a Li element-containing compound and a metal element-containing compound containing any metal element selected from Co, Ni, Mn, Fe, Fe, and Ti. Can be preferably used. 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 metal element-containing compounds include carbonates, chlorides, nitrates, sulfates, perchlorates, acetates, phosphates, bromates, etc. of other metal elements such as Li elements or Co elements. Can do. Among them, in the present invention, carbonates, chlorides, nitrates, and acetates are preferable 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 positive electrode current collectors.

For example, as the metal element-containing compound for generating LiCoO ₂ as the first binder 22, a Li element-containing compound and a Co element-containing compound can be used in combination as main raw materials, and if necessary, Other raw materials can also be used in combination. Examples of the Li element-containing compound include lithium carbonate, lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate. Examples of the Co element-containing compound include cobalt carbonate, cobalt (II) chloride hexahydrate, cobalt (II) formate dihydrate, cobalt (III) acetylacetonate, and cobalt (II) acetylacetonate dihydrate. , Cobalt (II) acetate tetrahydrate, cobalt (II) oxalate dihydrate, cobalt (II) nitrate hexahydrate, cobalt (II) ammonium hexahydrate, cobalt (III) nitrite Examples thereof include sodium and cobalt (II) sulfate heptahydrate. 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.

The metal element-containing compounds to produce LiNiO ₂ as the first binder material 22, Li-element-containing compound, and a Ni element-containing compound can be used in combination as the main raw material, further, if necessary Other raw materials can also be used in combination. 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 carbonate, nickel (II) chloride hexahydrate, and nickel (II) acetate. Tetrahydrate, nickel (II) perchlorate hexahydrate, nickel (II) bromide trihydrate, nickel (II) nitrate hexahydrate, nickel (II) acetylacetonate dihydrate, Examples thereof include nickel (II) hypophosphite 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, as the metal element-containing compound for generating LiMn ₂ O ₄ as the first binding substance 22, a Li element-containing compound and a Mn element-containing compound can be used in combination as main raw materials, If necessary, other raw materials can be used in combination. Examples of the Li element-containing compound are the same as in the case of producing LiCoO ₂ described above. Examples of the Mn element-containing compound include manganese carbonate, manganese (III) acetate dihydrate, and manganese (II) nitrate. Examples include hexahydrate, manganese (II) sulfate pentahydrate, manganese (II) oxalate dihydrate, and manganese (III) acetylacetonate. 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.

The metal element-containing compounds to produce LiFeO ₂ as a first binder material 22, can be used in combination Li element-containing compound, and a Fe element-containing compound as main components, further, needs Accordingly, other raw materials can be used in combination. 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.

The metal element-containing compound to produce the Li ₄ Ti ₅ O ₁₂ as the first binder material 22, can be used in combination Li element-containing compound, and a Ti element-containing compound as main components, Furthermore, 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 0.8 ≦ X <2, and 0.8 ≦ More preferably, X ≦ 1.2.

  In the positive 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 positive electrode current collector 1 and the positive electrode active material layer 2 generated on the current collector surface can be satisfactorily adhered, and the positive electrode active material particles 21 Is secured. In addition, by setting the concentration to 5 mol / L or less, the positive electrode active material layer forming liquid can be maintained at a satisfactory viscosity so that the surface of the positive electrode current collector 1 can be satisfactorily applied. A coating film can be formed.

  Further, the positive electrode active material layer forming liquid may be blended with a conductive material, an organic substance that is a viscosity adjusting agent of the positive 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 coating the positive electrode active material layer forming liquid on the positive electrode current collector 1 is not particularly limited, and a general coating method can be appropriately selected and used. For example, the coating liquid can be applied to an arbitrary region on the surface of the positive electrode current collector by a printing method, spin coating, dip coating, bar coating, spray coating, or the like. In addition, when the surface of the positive electrode current collector is porous, has a large number of irregularities, or has a three-dimensional structure, it can be applied manually in addition to the above method. is there. Note that the positive electrode current collector used in the present invention can be further improved in film formability of the positive electrode active material layer by performing corona treatment, oxygen plasma treatment, or the like in advance as necessary.

  Moreover, there is no limitation in particular about the coating amount of a positive electrode active material layer formation liquid, However, It is preferable to apply in the range in which the thickness after a heating becomes the thickness of the positive 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 (first binding substance 22) from the metal element-containing compound. . Specifically, it is a step of thermally decomposing the metal element-containing compound to generate the first binding substance 22. Then, the positive electrode plate 10 in which the positive electrode current collector 1, the positive electrode active material particles 21, and the positive electrode active material particles 21 are fixed to each other by the first binder 22 is manufactured through the heating step.

  About the heating temperature in a heating process, what is necessary is just the temperature which can thermally decompose the metal element containing compound used, Therefore Therefore, according to these kind, it can set suitably.

  In addition, the heating method is not particularly limited as long as the heating method or the heating apparatus 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. Especially when an aluminum foil is used as the positive electrode current collector, even if the heating step is performed in an air atmosphere, the aluminum foil has an oxide film on the surface, and there is no risk of oxidation to the inside of the aluminum foil. Preferably a heating process can be implemented.

  On the other hand, when a copper foil is used as the positive electrode 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 in which oxygen gas is not sufficiently contained, in the case where the positive electrode active material composed of the first binder material is generated in the positive electrode active material layer, Since the oxidation of the metal element needs to be realized by the combination of the oxygen atom in the compound contained in the positive electrode active material layer forming liquid and the metal element, the compound to be used contains an oxygen atom. It is necessary to use a compound.

  The inert gas atmosphere or the reducing gas atmosphere is not particularly limited to a specific atmosphere, and can be appropriately performed in these conventionally known atmospheres. For example, as the inert gas atmosphere, argon gas, nitrogen gas, reducing gas can be used. Examples of the gas atmosphere include hydrogen gas, carbon monoxide gas, or a gas atmosphere in which the inert gas and the reducing gas are mixed.

<< Negative Electrode Plate >>
Next, the negative electrode plate 50 constituting the nonaqueous electrolyte secondary battery 100 of the present invention will be described. The negative electrode plate 50 includes a negative electrode active material layer 54 formed on the negative electrode current collector 55, and the negative electrode active material layer 54 is a second binding material made of negative electrode active material particles and a metal or metal oxide. The negative electrode current collector, the negative electrode active material particles, and the negative electrode active material particles are fixed to each other by the second binding material. Thus, the present invention replaces a part or all of the conventional resin binder with a second binding material made of a metal or a metal oxide, the negative electrode current collector 55 and the negative electrode active material particles, Further, the battery characteristics of the negative electrode plate 50 are improved by fixing the negative electrode active material particles to each other. Further, the negative electrode plate 50 is combined with the positive electrode plate 10 having excellent rate characteristics as described above, so that a high temperature environment is obtained. Even if it is a case where it uses below, it can be set as the nonaqueous electrolyte secondary battery excellent in the battery characteristic. Hereinafter, the negative electrode current collector 55 and the negative electrode active material layer 54 will be described more specifically.

  2A and 2B, the negative electrode plate 50 includes the positive electrode current collector 1, the positive electrode active material layer 2, the positive electrode active material particles 21, and the first binder material 22. These can be replaced with the negative electrode current collector 55, the negative electrode active material layer, the negative electrode active material particles, and the second binder material, respectively, and detailed description thereof will be omitted.

<Negative electrode current collector>
There is no limitation in particular about the negative electrode collector 55, The conventionally well-known negative electrode collector 55 used for the negative electrode plate for nonaqueous electrolyte secondary batteries can be selected suitably, and can be used. For example, a negative electrode current collector formed of a simple substance such as an aluminum foil, a nickel foil, or a copper foil or an alloy can be preferably used. Similarly to the positive electrode current collector 1, the negative electrode current collector 55 includes a material in which a material for ensuring conductivity is laminated on the surface and a material on which some surface treatment is performed.

  The thickness of the negative electrode current collector 55 is not particularly limited as long as it is a thickness that can generally be used as a negative electrode current collector of a negative electrode plate for a non-aqueous electrolyte secondary battery, but is preferably 5 to 200 μm, preferably 10 to 50 μm. It is more preferable that

<Negative electrode active material layer>
The negative electrode active material layer 54 formed on the negative electrode current collector 55 is composed of negative electrode active material particles and a metal or metal oxide. The negative electrode current collector 55, the negative electrode active material particles, and the negative electrode active material particles are fixed to each other by the metal or metal oxide, thereby forming the negative electrode active material layer 54 on the negative electrode current collector 55. Thus formed negative electrode plate 50 is formed.

  The layer thickness of the negative electrode active material layer 54 is not particularly limited, but the layer thickness is preferably 50 μm to 150 μm in order to obtain a high capacity while improving rate characteristics. By setting the layer thickness of the negative electrode active material layer 54 in this range, the distance between the negative electrode active material layer 54 and the negative electrode current collector 55 can be shortened, and the impedance of the negative electrode plate 50 can be lowered.

  Moreover, it is preferable that the negative electrode active material layer 54 has a void to such an extent that the nonaqueous electrolytic solution can permeate. The porosity is not particularly limited as long as the nonaqueous electrolyte can permeate, but when the porosity is less than 10%, the nonaqueous electrolyte does not penetrate and smooth charge and discharge can be performed. May be difficult. Considering this point, the porosity of the negative electrode active material layer 54 is preferably 10% or more. Moreover, when the porosity is larger than 70%, the volume energy density cannot be increased, which may hinder the miniaturization of the non-aqueous electrolyte secondary battery. Considering this point, the porosity is preferably 70% or less. The porosity can be measured with Autopore IV 9500 manufactured by Shimadzu Corporation.

(Negative electrode active material particles)
The negative electrode active material layer 54 constituting the negative electrode plate 50 contains negative electrode active material particles. The negative electrode active material particles are not particularly limited, and conventionally known negative electrode active material particles can be appropriately selected and used in the field of non-aqueous electrolyte secondary batteries. For example, natural graphite, artificial graphite, amorphous carbon, carbon black, carbon materials obtained by adding different elements to these components, metallic lithium and its alloys, tin, silicon and their alloys, and oxides of silicon and titanium cobalt Examples thereof include materials capable of occluding and releasing alkali metal ions, such as nitrides of Mn, Fe, and Co. Among these, carbon materials are particularly suitable as negative electrode active material particles because of their low cost, easy handling, large energy that can be extracted per unit mass, low discharge potential, and good flatness. is there.

  The shape of the negative electrode active material particles is not particularly limited, and for example, a scale shape, a flat shape, a spindle shape, or a spherical shape can be used. Further, the particle size of the negative electrode active material particles is not particularly limited, and those having an arbitrary size can be appropriately selected and used in consideration of the thickness of the designed negative electrode active material layer 54 and the like. In addition, like the positive electrode active material particles described above, the rate and configuration can be improved by reducing the particle diameter of the negative electrode active material particles. Therefore, the particle diameter of the negative electrode active material particles is preferably less than 10 μm, preferably 5 μm or less, and particularly preferably 1 μm or less.

(Second binder)
The negative electrode current collector, the negative electrode active material particles, and the second binding material for fixing the negative electrode active material particles to each other are made of a metal or a metal oxide, and the metals include alkali metals, alkaline earth metals, transitions A metal can be used suitably. Examples of such a metal include copper, nickel, and lithium. As the metal oxide, oxides of these metals, transition metal composite oxides such as lithium titanate (Li ₄ Ti ₅ O ₁₂ , Li ₂ Ti ₃ O ₇ ), and the like can be suitably used. . In particular, transition metals are chemically stable, can form multiple oxidation numbers, and form multiple complexes with the same element. Therefore, a transition metal, an oxide of this metal, or a composite oxide containing this metal is highly convenient as a binder.

(Other materials)
The negative electrode active material layer 54 may be composed of only the above-described negative electrode active material particles and the second binder material, but may be formed by adding further additives without departing from the spirit of the present invention. Also good. For example, in the present invention, it is possible to exert good conductivity without using a conductive material, but depending on the case where better conductivity is desired or depending on the type of negative electrode active material particles, the conductive material may be It may be used.

(Method for manufacturing negative electrode plate)
Below, an example of the manufacturing method for manufacturing the negative electrode plate 50 of this invention is demonstrated. As a manufacturing method of the negative electrode plate 50 of the present invention, a negative electrode current collector, negative electrode active material particles, and a negative electrode plate manufacturing method in which negative electrode active material particles are fixed to each other with a second binding material made of a metal oxide. And a method of manufacturing a negative electrode plate fixed with a second binder made of metal. This will be specifically described below.

(1) Manufacturing method of negative electrode plate in which second binding material is metal oxide A negative electrode plate in which a negative electrode current collector, negative electrode active material particles, and negative electrode active material particles are fixed to each other by a metal oxide A negative electrode active material layer forming liquid is prepared using substance particles, a binder precursor containing a metal element, a solvent, and other materials as necessary, and the liquid is applied onto the negative electrode current collector 55. Then, the coating film can be manufactured by heating.

  As the negative electrode active material particles, the negative electrode active material particles described above can be appropriately selected and used, and description thereof is omitted here.

  The binder precursor used for the preparation of the negative electrode active material layer forming liquid is a precursor containing a metal element, such as a chloride, carbonate, nitrate, acetate, perchlorate, phosphoric acid of the metal element. Examples thereof include metal salts such as salts and bromates, and hydrates of these metal salts. Among them, chlorides, carbonates, nitrates, and acetates are easily available as general-purpose products, and these binder substance precursors are dissolved in a solvent to form a negative electrode active material layer forming liquid as a negative electrode current collector 55. When a coating film is formed on the coating film and heated, chlorine ions, carbonate ions, nitrate ions and acetate ions can be easily removed from the coating film, and these can be used particularly preferably.

  Specific examples of these binder precursors include, for example, when the metal element is copper, copper chloride, copper (II) carbonate, copper nitrate, copper acetate, copper acetate (II) monohydrate. When the metal element is nickel, nickel chloride, nickel carbonate, nickel nitrate, nickel acetate, nickel (II) nitrate hexahydrate, nickel acetate (II) tetrahydrate, etc. When the metal element is lithium, lithium chloride, lithium carbonate, lithium nitrate, lithium acetate, lithium acetate trihydrate, and the like can be given.

  The solvent for dissolving the binder precursor is not particularly limited as long as it can dissolve the precursor, and the same solvents as those described in the method for producing the positive electrode plate can be used.

  In the coating liquid described above, the ratio of the total amount of one or more binder substances added to the solvent is 0.01 to 20 mol / L, particularly 0.1 to 10 mol / L. L is preferred. By setting the concentration to 0.01 mol / L or more, the negative electrode current collector 55 and the negative electrode active material layer 54 formed on the surface of the current collector 55 can be satisfactorily adhered, and the negative electrode active material particles Adhesion to the negative electrode current collector is sufficiently achieved. In addition, by setting the concentration to 20 mol / L or less, it is possible to maintain a good viscosity so that the coating solution can be satisfactorily applied to the surface of the negative electrode current collector 55 and form a uniform coating film. can do.

  The method for coating the negative electrode active material layer coating liquid containing the binder precursor on the negative electrode current collector 55 is not particularly limited, and a method similar to the coating method used for manufacturing the positive electrode plate is appropriately selected. Can be used. The same applies to the thickness of the coating amount.

  By heating the binder material precursor contained in the coating liquid for forming the negative electrode active material layer, the negative electrode active material particles and the metal oxide obtained by oxidizing the metal of the binder material precursor by a chemical reaction are included. A coated film is formed. In the formed coating film, a metal oxide is formed so as to cover the surface of the negative electrode active material particles, and the negative electrode active material particles, the negative electrode current collector 55, and the negative electrode active material particles are formed by this metal oxide. It adheres and the negative electrode plate 50 is manufactured.

  Moreover, the heating temperature should just be more than the temperature which can oxidize the metal contained in a binder substance precursor, and although it changes with kinds of metal contained in a binder substance precursor, it is usually 120 to 800 degreeC. It is a temperature range.

(2) Method for producing negative electrode plate in which second binding material is metal By performing a reduction treatment on the metal oxide formed as described above, the metal oxide is reduced to a metal, and the reduced metal The negative electrode current collector 55, the negative electrode active material particles, and the negative electrode plate 50 in which the negative electrode active material particles are fixed to each other can be manufactured.

  As a reduction treatment method, a reduction treatment method in which a reduction treatment is performed in a hydrogen plasma atmosphere, a reduction gas obtained by diluting hydrogen, carbon monoxide, or the like with hydrogen, carbon monoxide, or an inert gas such as nitrogen, helium, argon, or the like. And a reduction treatment method in which reduction is performed in the reducing gas atmosphere can be suitably used. As the reducing gas, one kind of reducing gas may be used alone, or two or more kinds of gases may be mixed and used.

  Further, the negative electrode plate 50 formed through the reduction treatment does not contain an oxide in the negative electrode active material layer 54, and does not cause a reduction reaction during initial charging. Thereby, it is possible to prevent the charge reaction from being hindered by the reduction reaction during the initial charge and the initial charge / discharge efficiency from being lowered.

<< Separator >>
Next, the separator which comprises the nonaqueous electrolyte secondary battery 100 of this invention is demonstrated. In the present invention, the separator includes a heat-resistant nitrogen-containing aromatic polymer and ceramic powder.

  According to the separator containing the heat-resistant nitrogen-containing aromatic polymer and the ceramic powder, the separator shape can be maintained even when the non-aqueous electrolyte secondary battery of the present invention is used under high temperature conditions. There is no ignition or explosion. Therefore, in combination with the effects of the positive electrode plate using the first binding material and the negative electrode plate using the second binding material, the battery can be used even under high temperature conditions. A non-aqueous electrolyte secondary battery having excellent characteristics and high safety can be obtained.

<Heat resistant nitrogen-containing aromatic polymer>
The heat-resistant nitrogen-containing aromatic polymer contained in the separator 70 is a polymer containing a nitrogen atom and an aromatic ring in the main chain, for example, an aromatic polyamide (hereinafter sometimes referred to as “aramid”), An aromatic polyimide (hereinafter sometimes referred to as “polyimide”), an aromatic polyamideimide, and the like can be given. Examples of the aramid include a meta-oriented aromatic polyamide (hereinafter sometimes referred to as “meta-aramid”) and a para-oriented aromatic polyamide (hereinafter sometimes referred to as “para-aramid”). In addition, para-aramid is preferable in terms of being easily porous.

  Para-aramid is obtained by condensation polymerization of a para-oriented aromatic diamine and a para-oriented aromatic dicarboxylic acid halide, and the amide bond is in the para position of the aromatic ring or an oriented position equivalent thereto (for example, 4, 4′- Biphenylene, 1,5-naphthalene, 2,6-naphthalene and the like, which are substantially composed of repeating units bonded in the opposite direction (orientation positions extending coaxially or in parallel). Specifically, poly (paraphenylene terephthalamide), poly (parabenzamide, poly (4,4′-benzanilide terephthalamide), poly (paraphenylene-4,4′-biphenylenedicarboxylic amide), poly (para Para-oriented or para-oriented, such as phenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloro-paraphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer Paraaramid having a structure according to the above can be exemplified.

  Further, para-aramid can be dissolved in a polar organic solvent to form a low-viscosity solution, and is excellent in coatability, so that para-aramid having an intrinsic viscosity of 1.0 dl / g to 2.8 dl / g is preferable. The intrinsic viscosity is preferably 1.7 dl / g to 2.5 dl / g. Further, if the intrinsic viscosity is less than 1.0 dl / g, sufficient film strength may not be obtained. If the intrinsic viscosity exceeds 2.8 dl / g, it may be difficult to form a stable para-aramid solution, and para-aramid may be precipitated, making it difficult to form a film.

  The polar organic solvent is, for example, a polar amide solvent or a polar urea solvent, and specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, tetramethylurea, etc. However, it is not limited to these. Para-aramid is porous and is preferably a fibrillar polymer. The fibril-like polymer is microscopically non-woven, has a layered and porous void, and forms a so-called para-aramid porous resin.

  The polyimide is preferably a wholly aromatic polyimide produced by condensation polymerization of an aromatic dianhydride and a diamine. Specific examples of the dianhydride include pyromellitic dianhydride, 3, 3 ′, 4, 4′-diphenylsulfone tetracarboxylic dianhydride, 3, 3 ′, 4, 4′-benzophenone tetracarboxylic acid. And acid dianhydrides, 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and the like. Specific examples of the diamine include oxydianiline, paraphenylenediamine, benzophenone diamine, 3,3′-methylenedianiline, 3,3′-diaminobenzophenone, 3,3′-diaminodiphenylsulfone, 1,5 '-Naphthalenediamine and the like can be mentioned, but the present invention is not limited to these. In the present invention, when a porous film is produced directly from a polyimide solution, a polyimide soluble in a solvent can be suitably used. Examples of the polyimide include a polycondensate polyimide of 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride and an aromatic diamine.

  As the polar organic solvent used for the polyimide, dimethyl sulfoxide, cresol, o-chlorophenol and the like can be suitably used in addition to those exemplified in the case of aramid.

  The polyimide is preferably porous. For example, a solid film can be made porous by machining or laser processing. Moreover, when creating a polyimide film by the solution casting method, a porous film can be created by controlling the molding conditions of polyimide such as the polymer concentration during coating. Further, by compounding ceramic powder, a uniform and fine porous material can be formed with a solution having an arbitrary polymer concentration. The air permeability can be controlled by the amount of ceramic powder added.

<Ceramic powder>
In the present invention, the separator contains ceramic powder. The ceramic powder is trapped by being entangled with the heat-resistant nitrogen-containing aromatic polymer, and is dispersed in the whole or part of the separator for the nonaqueous electrolyte battery.

  The ceramic powder in the present invention preferably has an average primary particle size of 1.0 μm or less, and a powder of 0.5 μm or less in view of the influence on the strength of the separator for nonaqueous electrolyte batteries and the smoothness of the coated surface. It is more preferable that it is 0.1 μm or less. The average particle diameter of the primary particles is measured by a method of analyzing a photograph obtained by an electron microscope using a particle diameter measuring instrument. When the average particle size of the primary particles of the ceramic powder exceeds 1.0 μm, the separator may become brittle and the coated surface may become rough. Further, the content of the ceramic powder is preferably 1% by weight or more and 95% by weight or less, more preferably 5% by weight or more and 50% by weight or less, based on the weight of the nonaqueous electrolyte battery separator. When the content of the ceramic powder is less than 1% by weight of the weight of the nonaqueous electrolyte battery separator, the effect of promoting ion permeability and battery characteristics may not be sufficient. When the content exceeds 95% by weight, the separator It may become brittle and difficult to handle. The shape of the ceramic powder is not particularly limited, and can be spherical or random.

  Examples of the ceramic powder include ceramic powders made of electrically insulating metal oxides, metal nitrides, metal carbides, and the like. For example, powders such as alumina, silica, titanium dioxide, or zirconium oxide are preferably used. The said ceramic powder may be used independently and can also be used in mixture of 2 or more types.

  The substrate is not particularly limited, and examples thereof include porous woven fabrics, nonwoven fabrics, paper or porous films made of electrically insulating organic, inorganic fibers or pulp. Among these, from the viewpoint of price and thinness. Nonwoven fabric, paper or porous film is preferred. The material of the substrate may be organic or inorganic as long as it is electrically insulating, and may be synthetic or natural. The substrate may be organic fiber and / or inorganic fiber and / or organic fiber pulp and / or inorganic. Examples include fiber pulp. Specifically, examples of organic fibers include fibers made of thermoplastic polymers and natural fibers such as manila hemp. Examples of the fibers made of the thermoplastic polymer include polyolefins such as polyethylene and polypropylene, fibers such as rayon, vinylon, polyester, acrylic, polystyrene, and nylon. Examples of the inorganic fiber include glass fiber and alumina fiber.

  In the present invention, the separator is formed by coating the above-mentioned base material with a heat-resistant nitrogen-containing aromatic polymer containing ceramic powder, or the heat-resistant nitrogen-containing aromatic polymer is formed in the voids of the base material. Even if the base material is formed by coating the base material with the heat-resistant nitrogen-containing aromatic polymer, and the space of the base material is filled with the heat-resistant nitrogen-containing aromatic polymer. Good.

In this case, the weight per unit area of the substrate is preferably 40 g / m ² or less, more preferably 15 g / m ² or less. The porosity of the substrate is preferably 40% or more, and more preferably 50% or more. Further, the thickness of the substrate is preferably 70 μm or less, and more preferably 25 μm or less.

  10% by weight or more, preferably 30% by weight or more, more preferably 40% by weight or more of a thermoplastic polymer that melts at 260 ° C. or less with respect to the entire separator, and the thermoplastic polymer melts when the temperature rises, It is preferable to close the gap of the separator. By including a thermoplastic polymer in the separator, when the temperature of the battery rises locally or as a whole, the thermoplastic polymer melts and enters the micropores of the separator, sealing the micropores, Do not flow. Furthermore, even when the temperature rises, it does not flow out because it enters not the surface but the micropores. In this way, since the battery is shut down, a separator with higher safety can be obtained. The thermoplastic polymer is not particularly limited as long as it melts when the temperature rises. The thermoplastic polymer is preferably a polymer that melts at 260 ° C. or less, more preferably 200 ° C. or less, from the viewpoint of the shutdown function. Moreover, since the melting temperature is appropriate as the shutdown temperature, it is preferably about 100 ° C. or higher.

  Examples of the thermoplastic polymer include polyolefin resin, acrylic resin, styrene resin, polyester resin, and nylon resin. In particular, polyethylene such as low density polyethylene, high density polyethylene and linear polyethylene, or their low molecular weight wax content, or polyolefin resin such as polypropylene is suitable because it has an appropriate melting temperature and is easily available. These may be used alone or in combination of two or more.

  The thermoplastic polymer used in the present invention is preferably a powder having an average particle size of preferably 10 μm or less, more preferably 6 μm or less, from the viewpoint of dispersibility in a solvent and smoothness of the coated surface. The shape of the powder particles is not particularly limited, and can be spherical or random.

  It is preferable that the thermoplastic polymer is disposed in the whole or part of the separator for the nonaqueous electrolyte battery in the form of particles, and the mode is such that the thermoplastic polymer melts when the temperature rises, and the separator Any mode may be used as long as the gap is closed.

<Manufacturing method of separator>
Next, an example of a separator manufacturing method will be described. In the present invention, the separator contains a heat-resistant nitrogen-containing aromatic polymer and a ceramic powder, and the following production is possible as long as it is a method capable of producing a separator having this requirement. The method is not limited.

  The separator prepares a slurry solution in which ceramic powder is dispersed in a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer. Next, this slurry solution is applied onto a substrate to form a coating film, a heat-resistant nitrogen-containing aromatic polymer is deposited on the coating film, and the polar organic solvent is removed from the coating film, It can manufacture by drying this coating film.

  The slurry solution preferably contains the thermoplastic resin that melts at 260 ° C. or less as described above. Moreover, it is preferable that the ceramic powder is dispersed within a range of 1 to 1500 parts by mass with respect to 100 parts by mass of the heat-resistant nitrogen-containing aromatic polymer.

  An example of using para-aramid and polyimide as the heat-resistant nitrogen-containing aromatic polymer will be described. In the case of using para-aramid, for example, in a polar organic solvent in which 2 to 10% by weight of an alkali metal or alkaline earth metal chloride is dissolved, the para-oriented aromatic dicarboxylic acid is 1.00 mol of the para-oriented aromatic diamine. A para-oriented aromatic polyamide concentration produced by adding 0.94 to 0.99 mol of acid dihalide and performing condensation polymerization at a temperature of −20 ° C. to 50 ° C. is 1 to 10%, and an intrinsic viscosity of 1.0 to Make a polar organic solvent solution of aramid that is 2.8 dl / g.

  As para-oriented aromatic diamines used in the condensation polymerization of para-aramid, paraphenylene diamine, 4,4′-diaminobiphenyl, 2-methyl-paraphenylene diamine, 2-chloro-paraphenylene diamine, 2,6-dichloro-paraphenylene Examples thereof include diamine, 2,6-naphthalenediamine, 1,5-naphthalenediamine, 4,4′-diaminobenzanilide, 3,4′-diaminodiphenyl ether, and the like. One or more para-oriented aromatic diamines can be mixed and used for condensation polymerization.

  As para-oriented aromatic dicarboxylic acid dihalide used for the condensation polymerization of para-aramid, terephthalic acid dichloride, biphenyl-4,4′-dicarboxylic acid dichloride, 2-chloroterephthalic acid dichloride, 2,5-dichloroterephthalic acid dichloride, 2-methyl Examples include terephthalic acid dichloride, 2,6-naphthalenedicarboxylic acid dichloride, 1,5-naphthalenedicarboxylic acid dichloride, and the like. One or more para-oriented aromatic diamines can be mixed and used for condensation polymerization.

  In order to improve the solubility of para-aramid in a solvent, an alkali metal or alkaline earth metal chloride is preferably used. Specific examples include lithium chloride or calcium chloride, but are not limited thereto.

  The amount of the chloride added to the polymerization system is preferably in the range of 0.5 to 6.0 mol, more preferably in the range of 1.0 to 4.0 mol, per 1.0 mol of the amide group produced by condensation polymerization. . If the chloride is less than 0.5 mol, the solubility of the resulting para-aramid may be insufficient, and if it exceeds 6.0 mol, the amount of chloride dissolved in the solvent may be substantially exceeded, which may not be preferable. is there.

  In general, if the alkali metal or alkaline earth metal chloride is less than 2% by weight, the solubility of para-aramid may be insufficient. If it exceeds 10% by weight, the alkali metal or alkaline earth metal chloride may be insufficient. May not dissolve in polar organic solvents such as polar amide solvents or polar urea solvents.

  If the para-aramid concentration is less than 0.5% by weight, productivity may be significantly reduced, which may be industrially disadvantageous. If the para-aramid exceeds 10% by weight, the para-aramid may precipitate and it may be difficult to form a stable para-aramid solution. Examples of the polar organic solvent solution of polyimide include aromatics such as 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride and 4,4′-bis (p-aminophenoxy) diphenylsulfone. An N-methyl-2-pyrrolidone solution of polyimide that has been imidized and obtained by a polycondensation reaction with diamine is exemplified. Examples of the polar organic solvent include cresol, o-chlorophenol and the like in addition to the above-described examples when polyimide is used.

  A slurry solution is prepared by sufficiently dispersing 1-1500 parts by weight, preferably 5-100 parts by weight, of the ceramic powder in 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer in the polar organic solvent solution. If the amount of the ceramic powder is less than 1 part by weight, the ion permeability and battery characteristics are not sufficiently improved, and if it exceeds 1500 parts by weight, the separator becomes unfavorable because it becomes brittle and difficult to handle. If necessary, a thermoplastic polymer may be added to the slurry solution.

  Next, this slurry solution is applied onto a base film, a steel belt, a roll, a drum or the like to form a wet coating film. Examples of the base film include polyethylene terephthalate and release-treated paper. In addition, coating on a corrosion-resistant steel belt having a mirror finish is often used industrially. On a small scale, it can also be coated on a mirror-finished, corrosion-resistant roll or drum.

  Examples of the coating method include coating methods such as knife, blade, bar, gravure, and die. On a small scale, coating with bars, knives and the like is simple, but industrially, die coating having a structure in which the solution does not come into contact with the outside air is preferable.

  Subsequently, the heat-resistant nitrogen-containing aromatic polymer is preferably deposited in an atmosphere controlled at a temperature of 20 ° C. or higher and constant humidity, and then immersed in a coagulation liquid. Alternatively, it is immersed in a coagulation solution, and polymer is deposited and coagulated at the same time to obtain a wet coating film. In order to perform the precipitation uniformly and quickly, a poor solvent, such as water, may be added to the slurry solution in advance to form a depositing liquid state.

  In the case of para-aramid, a polymer is precipitated at the same time as evaporating a part or all of the solvent, that is, the following solvent removal step and precipitation step are simultaneously performed to obtain a semi-dried or dried coating film.

As the coagulation liquid here, an aqueous solution or an alcohol solution may be used, and it is not particularly limited. However, an aqueous solution or an alcohol solution containing a polar organic solvent is used industrially as a solvent recovery step. This is preferable because it is simplified. Specific examples include an aqueous solution of a polar organic solvent.

  Next, the polar organic solvent is removed from the coating film on which the heat-resistant nitrogen-containing aromatic polymer is deposited. As a removal method, a part or the whole may be evaporated, or the solvent may be removed with a solvent capable of dissolving a polar organic solvent such as water, an aqueous solution, or an alcohol solution. When removing using water, it is preferable to use ion-exchange water. Further, it is industrially preferable to wash in an aqueous solution containing a certain concentration of a polar organic solvent and then wash with water. In drying, the washing solvent is removed by evaporation. The drying temperature at this time is preferably equal to or lower than the melting temperature when the thermoplastic polymer to be melted is contained.

  When para-aramid is prepared using an alkali metal or alkaline earth metal chloride, the alkali metal or alkaline earth metal chloride is washed and removed together with the solvent from the wet coating film on which the para-aramid is deposited. Alternatively, the alkali metal or alkaline earth metal chloride is washed and removed from the dried coating film. As this removal method, a method of immersing the coating film in a solution and eluting the solvent and chloride is employed. As the solution for eluting the solvent or chloride, water, an aqueous solution, or an alcohol solution is preferable because it can dissolve both the solvent and the chloride.

  Subsequently, the target dry coating film can be manufactured by drying below the melting temperature of the polymer to be heated and melted. This formed dry coating film can be used as a separator as it is. From the viewpoint of imparting shutdown performance, a thermoplastic polymer is preferably included, but may be included in any step. Further, it is preferable to apply a fine particle suspension of a thermoplastic resin to a dry coating film by further applying and drying a fine suspension of a thermoplastic polymer.

(Non-aqueous electrolyte)
The non-aqueous electrolyte 90 used in the non-aqueous electrolyte secondary battery of 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, 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 nonaqueous electrolyte battery 100 manufactured using the positive electrode plate 10, the negative electrode plate 50, the separator 70, and the nonaqueous electrolyte solution 90, a conventionally known structure can be appropriately selected and used. For example, the structure which winds said positive electrode plate 10 and the negative electrode plate 50 in the shape of a spiral via the separator 70, and accommodates in a battery container is mentioned. As another aspect, a structure in which the positive electrode plate 10 and the negative electrode plate 50 cut into a predetermined shape are stacked and fixed via a separator 70, and this is housed in a battery container may be employed. In any structure, after the positive electrode plate 10 and the negative electrode plate 50 are accommodated 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 being attached to the negative electrode plate. A non-aqueous electrolyte secondary battery is manufactured by connecting the lead wire to a negative electrode terminal provided in the exterior container, and further filling the battery container with a non-aqueous electrolyte and then sealing the battery container.

(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. .

  The battery pack 200 can appropriately select the configuration of a conventionally known battery pack, except that the nonaqueous electrolyte secondary battery 100 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.

  The non-aqueous electrolyte secondary battery 100 of the present invention has functions such as an overcurrent blocking function and a battery temperature monitor in addition to the above-described protection circuit, in addition to the usage mode for the battery pack. You may use for the aspect attached integrally to a nonaqueous 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.

<Preparation of positive electrode plate 1>
Li (CH ₃ COO) · 2H ₂ O [molecular weight: 102.02]: 1.0 g added to methanol: 1.0 g and Mn (CH ₃ COO) ₂ · 4H ₂ O [molecular weight: 245.09] : Lithium composite oxide in which 5 g is added to 5 g of methanol and mixed in an amount of Li (CH ₃ COO): Mn (CH ₃ COO) = 2.1 g: 9.8 g Was used as a raw material solution. Next, 5 g of the above raw material solution, 10 g of a positive electrode active material LiMn ₂ O ₄ having an average particle diameter of 4 μm, 1.2 g of acetylene black (Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.), carbon fiber (manufactured by Showa Denko KK, VGCF) ) 0.25 g, silane coupling agent KBM403: 1.5 g, resin hydroxyethyl cellulose: 10 g of a thickener aqueous solution in which 0.2 g is dissolved in pure water: 9.8 g, and solvent methanol are mixed, and an Excel auto homogenizer ( Nippon Seiki Seisakusho Co., Ltd.) kneaded at a rotational speed of 8000 rpm for 15 minutes to prepare a positive electrode active material layer forming liquid 1.

  Next, an aluminum plate having a thickness of 15 μm is prepared as a current collector, and the positive electrode active material layer forming liquid 1 prepared above is applied to one surface side of the current collector with an applicator to form a positive electrode active material layer forming coating. A film was formed. 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. Next, the current collector with the electrode active material layer-forming coating film formed on the surface was placed in a normal temperature electric furnace (Muffle furnace, manufactured by Denken, P90), and from room temperature to 450 ° C. over 20 minutes. After heating, a positive electrode plate 1 having a positive electrode active material layer provided on a current collector was obtained.

<Preparation of negative electrode plate 1>
2.5 g of copper nitrate was added to 10 g of ethanol solvent, and 3.5 g of artificial graphite particles having an average particle diameter of 6 μm were mixed as negative electrode active material particles to prepare a negative electrode active material layer forming liquid. Next, an electrolytic copper foil having a thickness of 10 μm and 25 cm × 30 cm is placed as a current collector, and the negative electrode active material layer forming solution is applied to the surface of the current collector by 127 μm using an applicator. Formed. And the collector provided with the said coating film is installed in the oven of an atmospheric condition, and the negative electrode plate A about 26 micrometers thick containing copper oxide and a graphite is contained by heating at 270 degreeC for 5 hours. Formed. Next, the negative electrode plate A is subjected to a reduction treatment for 30 seconds with a microwave surface wave plasma irradiation apparatus (microwave output) using hydrogen at a pressure of 20 Pa as a carrier gas to reduce the copper oxide to copper particles as metal particles. A plate 1 was obtained.

<Preparation of separator>
(Preparation of PPTA dope for coating)
Poly (paraphenylene terephthalamide) (hereinafter sometimes abbreviated as PPTA) is produced using a 3 liter separable flask having a stirring blade, a thermometer, a nitrogen inflow pipe and a powder addition port. It was. The flask was sufficiently dried, charged with 2200 g of N-methyl-2-pyrrolidone, 151.07 g of calcium chloride powder vacuum-dried at 200 ° C. for 2 hours was added, and the temperature was raised to 100 ° C. for complete dissolution. After returning to room temperature, 68.23 g of paraphenylenediamine was added and completely dissolved. While maintaining this solution at 20 ° C. ± 2 ° C., 124.97 g of terephthalic acid dichloride was added in 10 divided portions every about 5 minutes. However, one of the terephthalic acid dichlorides divided into 10 was dissolved in NMP having the same weight as that of terephthalic acid dichloride and finally added. Thereafter, with stirring, the solution was aged for 1 hour while maintaining the temperature at 20 ° C. ± 2 ° C. It filtered with the 1500 mesh stainless steel wire mesh. The obtained solution showed optical anisotropy in a liquid crystal phase having a PPTA concentration of 6%. A part of the PPTA solution was sampled, and the inherent viscosity of PPTA obtained by reprecipitation with water was 2.01 dl / g.

  100 g of the above PPTA dope is weighed into a 500 ml separable flask having a stirring blade, thermometer, nitrogen inlet tube and liquid addition port, 140 g of NMP is added, and finally the PPTA concentration is 2.5. The solution was prepared in a weight percent isotropic phase solution and stirred for 60 minutes. 6 g of alumina fine particles (manufactured by Nippon Aerosil Co., Ltd .; Alumina C) were mixed with a solution having the PPTA concentration of 2.5% by weight and stirred for 240 minutes. The coating dope in which the fine alumina particles were sufficiently dispersed was filtered through a nanomesh three times through a 1000 mesh wire net. Thereafter, defoaming was performed under reduced pressure to obtain a slurry for coating.

(Preparation of porous film layer)
A PET film having a thickness of 100 μm was wound on a drum having a diameter of 550 mm and a length of 350 mm. A substrate (polyethylene separator, basis weight 10.5 g / m ² , thickness 16 μm, porosity 40%) was wound on a PET film. One side of the substrate was fixed to the drum with tape. A weight of 0.6 kg was suspended on the other side so that a load was evenly applied to the substrate. A stainless steel coating bar having a diameter of 25 mm was arranged in parallel at the top of the drum so that the clearance from the drum was 0.15 mm. The drum was rotated and stopped so that the end of the base fixed with the tape came between the drum and the coating bar. While supplying the coating dope prepared above on the substrate in front of the coating bar, the drum was rotated at 0.5 rpm to coat the substrate. The whole substrate was applied, and while rotating the drum, it was placed in an atmosphere of 50% humidity at 23 ° C. for 10 minutes to precipitate PPTA. The 100-μm PET film and the film on which the dope was applied and deposited on the substrate were integrated and removed from the drum, immersed in ion-exchanged water, and washed for 12 hours while flowing ion-exchanged water. Take the PET film after washing, sandwich the wet film between the polyester cloth from both sides, and further sandwich it with an aramid felt, place it on a 3 mm thick aluminum plate, put a 0.1 mm thick nylon film on it, The periphery was sealed with a sealing material, and the interior was evacuated and dried at 70 ° C. for 6 hours to obtain a separator 1.

(Physical properties of separator 1)
The separator 1 had a thickness of 24.0Myuemu, basis weight 17.0 g / m ² (polyethylene separator ^{10.5g / m 2, PPTA3.2g / m} 2, alumina 3.2 g / m ^2), the porosity 59 of the heat-resistant layer. 4%. When the film was observed with a scanning electron microscope, one side was made of a fibrillar or layered PPTA resin of about 0.1 μm or less, alumina fine particles having a particle size of about 0.013 μm were dispersed between the fibrils, and the pore size was 0. It was a porous layer having pores of 0.05 to 0.2 μm. When the cross section was observed, it was a two-layer structure in a state where PPTA resin entered and adhered to the polyethylene separator of the base material. The air permeability of the separator was 43 cc / sec.

(Shutdown performance measurement)
The internal electrical resistance at 25 ° C. before heating of the separator 1 was 20Ω. As the temperature was raised, the internal electrical resistance gradually decreased, but the internal electrical resistance started to increase from around 130 ° C. and increased to 2 kΩ around 135 ° C. Furthermore, although the temperature was raised to 200 ° C., there was no decrease in electrical resistance due to meltdown.

<Preparation of non-aqueous electrolyte>
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.

<Production of nonaqueous electrolyte battery>
The non-aqueous electrolyte secondary battery has a flat plate structure with a positive electrode area of 2.34 cm ² , and the negative electrode plate 1, the separator, and the positive electrode plate 1 are stacked in this order in an argon atmosphere box, and then the non-aqueous electrolyte solution is applied to the separator. The non-aqueous electrolyte secondary battery of Example 1 sufficiently impregnated was obtained.

(Comparative Example 1)
Except that the positive electrode plate 1 and the negative electrode plate 1 of Example 1 were changed to the positive electrode plate 2 and the negative electrode plate 2 obtained by the following method, the nonaqueous electrolyte solution 2 of Comparative Example 1 was used in the same manner as Example 1. The next battery was obtained.

<Preparation of positive electrode plate 2>
Positive electrode active material having an average particle size of 4 μm: LiMn ₂ O ₄ 10 g, acetylene black (Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.): 1.2 g, carbon fiber (Showa Denko Co., Ltd., VGCF) 0.25 g, polyfluoride A positive electrode active material layer forming solution 2 was prepared by mixing 10 g of a 12% concentration solution of vinylidene chloride (PVdF) dissolved in NMP and kneading with an Excel auto homogenizer (Nihon Seiki Seisakusho Co., Ltd.) at a rotation speed of 8000 rpm for 15 minutes. Prepared. An aluminum plate having a thickness of 15 μm is prepared as a current collector, and the electrode active material layer forming solution 2 prepared above is applied to one side of the current collector with an applicator to form a coating film for forming a positive electrode active material layer. Formed. Next, using a roll press machine (manufactured by Sank Metal Co., Ltd .: mechanical type 1 ton), the above-mentioned coating film was pressed under the conditions of applied pressure: 0.1 ton / cm and pressing speed of 10 mm / second on the current collector A positive electrode plate 2 provided with a positive electrode active material layer was obtained.

<Preparation of negative electrode plate 2>
A coating solution 2 for forming a negative electrode active material is prepared by mixing 10 g of a 12% concentration solution of polyvinylidene fluoride (PVdF) in NMP and 3.5 g of artificial graphite particles having an average particle diameter of 6 μm as negative electrode active material particles. Prepared. Next, an electrolytic copper foil having a thickness of 10 μm and 25 cm × 30 cm is placed as a current collector, and the negative electrode active material forming coating liquid 2 is applied to the current collector by 127 μm using an applicator. A coating film was formed. Next, using a roll press machine (manufactured by Sank Metal Co., Ltd .: mechanical type 1 ton), the above-mentioned coating film was pressed under the conditions of applied pressure: 0.1 ton / cm and pressing speed of 10 mm / second on the current collector A negative electrode plate 2 provided with a negative electrode active material layer was obtained.

(Measurement of discharge capacity)
The nonaqueous electrolyte secondary battery of Example 1 and Comparative Example 1 was repeated 20 cycles at a charge voltage of 4.2 V and a discharge voltage of 2.75 V, and the discharge capacity at 20th cycle (discharge current 1.5 mA) was measured. The discharge capacity was 1 C. The discharge capacity is shown in Table 1.

(Measurement of discharge capacity after heating)
Moreover, after heating the non-aqueous-electrolyte secondary battery of Example 1 and the comparative example 1 before charge for 10 minutes at 120 degreeC, the discharge capacity in 1C was measured. Table 1 also shows the discharge capacity after heating.

  As can be seen from the above table, the non-aqueous electrolyte secondary battery of Example 1 in which both the positive electrode plate and the negative electrode plate contained a metal oxide as a binder in the electrode active material layer was heated at 120 ° C. Even after the discharge, the discharge capacity did not decrease and good battery characteristics could be obtained. Even when heated at 120 ° C., there is no ignition or explosion, and the safety is excellent. On the other hand, in the comparative example using a resin binder as the binder, the discharge capacity was remarkably lowered after heating at 120 ° C.

DESCRIPTION OF SYMBOLS 1 ... Positive electrode collector 2 ... Positive electrode active material layer 10 ... Positive electrode plate 21 ... Positive electrode active material particle 22 ... 1st binding material 32 ... Positive electrode terminal 33 ... Negative terminal 34 ... Protective circuit board 35 ... External connector 36a, 36b ... Resin container 37 ... End case 38a, 38b ... External connection window 50 ... Negative plate 54 ... Negative electrode active material layer 55 ... Negative electrode current collector 70 ... Separator 81, 82 ... Exterior 100 ... Nonaqueous electrolyte secondary battery 200 ... Battery pack

Claims (2)

A positive electrode plate having a positive electrode active material layer on the positive electrode current collector, a negative electrode plate having a negative electrode active material layer on the negative electrode current collector, a separator provided between the positive electrode plate and the negative electrode plate, and a non-aqueous solvent A non-aqueous electrolyte secondary battery comprising at least an electrolyte containing
The positive electrode active material layer contains positive electrode active material particles and a first binding material made of a metal oxide,
The negative electrode active material layer contains negative electrode active material particles and a second binder made of metal or metal oxide,
The positive electrode active material particles, the positive electrode current collector, and the positive electrode active material particles are fixed to each other by the first binder, and the negative electrode active material particles, the negative electrode current collector, and the The negative electrode active material particles are fixed to each other by the second binder material,
The non-aqueous electrolyte secondary battery, wherein the separator includes a heat-resistant nitrogen-containing aromatic polymer and ceramic powder. 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 are provided, and the storage case includes the non-aqueous electrolyte secondary battery and the protection In a battery pack configured to contain a circuit,
The battery pack, wherein the non-aqueous electrolyte secondary battery is the non-aqueous electrolyte secondary battery according to claim 1.

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