JP5800196B2 - Non-aqueous electrolyte secondary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a nonaqueous electrolyte secondary battery, and more particularly to a nonaqueous electrolyte secondary battery in which a filler layer is disposed between a positive electrode and a negative electrode.

  In recent years, lithium-ion secondary batteries, nickel-metal hydride batteries, and other secondary batteries have become increasingly important as power sources mounted on vehicles using electricity as power sources, or power supplies mounted on personal computers, mobile terminals, and other electrical products. Yes. In particular, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery that is lightweight and has a high energy density is expected to be preferably used as a high-output power source mounted on a vehicle. One typical configuration of this type of non-aqueous electrolyte secondary battery includes an electrode body in which a positive electrode and a negative electrode are laminated via a separator sheet. Some separator sheets have a filler layer containing a filler formed on the surface of the separator sheet for the purpose of preventing a short circuit due to thermal contraction of the separator sheet. Patent documents 1 and 2 are mentioned as a prior art using boehmite as a filler.

JP 2008-210784A JP 2008-243825 A

  However, aluminum (Al) -containing inorganic materials such as boehmite described above often contain sodium (Na) in the production process. Since Na has a property of adsorbing moisture, a battery using such an Al-containing inorganic material as a filler layer is likely to contain moisture, and impurities (typical) are caused by the reaction of this moisture with a non-aqueous electrolyte. Has a problem that hydrogen fluoride (HF)) is generated, battery resistance increases due to such impurities, and battery capacity decreases.

  The present invention was created to solve the above-described problems, and an object thereof is to provide a non-aqueous electrolyte secondary battery with low battery resistance and suppressed capacity reduction. Another object of the present invention is to provide a method for producing a nonaqueous electrolyte secondary battery having such performance.

In order to achieve the above object, the present invention provides a method for producing a nonaqueous electrolyte secondary battery. This production method has the general formula:
Al ₂ O _3. (H ₂ O) _x
(Wherein x satisfies 0 ≦ x ≦ 2) substantially composed of an inorganic material, and contains sulfur (S) in a filler containing sodium (Na) and sulfur (S) as trace components The amount is adjusted to at least 10 ppm (typically 10 ppm to 50 ppm) on a mass basis, a positive electrode and a negative electrode are prepared, and a filler layer is formed between the positive electrode and the negative electrode using the adjusted filler. And, when the inorganic material of the filler satisfies 1 ≦ x ≦ 2 in the general formula, it is obtained by a wide-angle X-ray diffraction spectrum (CuKα). In which the X-ray peak intensity ratio I (020) / I (120) of the inorganic material is from 5 to 200, or the inorganic material of the filler is 0 ≦ x <1 in the general formula If you meet , Those X-ray peak intensity ratio I of the inorganic material obtained by wide angle X-ray diffraction spectrum (CuKα) (116) / I (110) is 5 to 200 is used.

  According to the method for producing a non-aqueous electrolyte secondary battery having such a configuration, a filler substantially composed of an inorganic material having the characteristics as described above is used, and the S content in the filler is set to the Na content. By adjusting so that it may become sufficient quantity, Na in the filler which has the property to adsorb | suck a water | moisture content will react with S contained enough, and the adsorption | suction of the water | moisture content by Na can be prevented. Therefore, the mixing of moisture into the battery due to Na is prevented, the generation of impurities due to the reaction between moisture and the non-aqueous electrolyte can be suppressed, and the increase in battery resistance due to such impurities is increased. This prevents the battery capacity from decreasing. In addition, by using an inorganic material represented by the above general formula having an X-ray peak intensity ratio of 5 or more, the initial capacity of the battery is increased, and the effect of reducing battery resistance by containing S is sufficient. can get. Further, by using an inorganic material represented by the above general formula having an X-ray peak intensity ratio of 200 or less, a charge carrier (for example, lithium (Li) ion in the case of a lithium ion secondary battery) has a filler layer. It becomes easy to pass and battery resistance can be reduced. Therefore, according to the production method of the present invention, it is possible to provide a lithium ion secondary battery and other nonaqueous electrolyte secondary batteries having low battery resistance and suppressed capacity reduction.

  In a preferred aspect of the method for producing a nonaqueous electrolyte secondary battery disclosed herein, the inorganic material satisfies 1 ≦ x ≦ 2 in the general formula, or the inorganic material In the general formula, 0 ≦ x <1 is satisfied.

According to the present invention, there is also provided a nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and a filler layer disposed between the positive electrode and the negative electrode, wherein the filler layer has the general formula:
Al ₂ O _3. (H ₂ O) _x
(Wherein x satisfies 0 ≦ x ≦ 2) and is substantially composed of a filler containing sodium (Na) and sulfur (S) as trace components as main components, When the sulfur (S) content in the filler is at least 10 ppm (typically 10 ppm to 50 ppm) on a mass basis, and the inorganic material satisfies 1 ≦ x ≦ 2, the wide angle The X-ray peak intensity ratio I (020) / I (120) of the inorganic material obtained by X-ray diffraction spectrum (CuKα) is 5 to 200, and the inorganic material is 0 ≦ x < 1 is satisfied, the X-ray peak intensity ratio I (116) / I (110) of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα) is 5 to 200. According to the non-aqueous electrolyte secondary battery having such a configuration, since a predetermined amount of S is contained in the filler, this S prevents moisture from being adsorbed by Na contained in the filler. In order to prevent moisture from being mixed into the battery as a cause, an increase in battery resistance due to such moisture mixing is prevented, and a decrease in battery capacity can be suppressed. In addition, since the X-ray peak intensity ratio of the inorganic material represented by the above general formula is set within a predetermined range, the initial capacity of the battery is increased, and the effect of reducing battery resistance by containing S is sufficient. In addition, the charge carrier can easily pass through the filler layer, and the battery resistance can be reduced.

  In a preferred aspect of the nonaqueous electrolyte secondary battery disclosed herein, the inorganic material satisfies 1 ≦ x ≦ 2 in the general formula, or the inorganic material is in the general formula. 0 ≦ x <1.

  Furthermore, according to this invention, a vehicle provided with the nonaqueous electrolyte secondary battery in any one disclosed here is provided. Such a non-aqueous electrolyte secondary battery has low battery resistance and suppresses a decrease in capacity. Therefore, a motor (electric motor) mounted on a vehicle such as an automobile equipped with an electric motor such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle. It can be suitably used as a power source for the vehicle.

It is a perspective view which fractures | ruptures and shows the lithium ion secondary battery which concerns on one Embodiment. It is an expanded sectional view of the separator concerning one embodiment. It is an expanded sectional view of the separator concerning other one embodiments. 1 is a side view of a vehicle according to an embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional relationship (length, width, thickness, etc.) in each drawing does not reflect the actual dimensional relationship. Further, matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters for those skilled in the art based on the prior art in this field.

  As a preferred embodiment of the nonaqueous electrolyte secondary battery disclosed herein, a lithium ion secondary battery will be described as an example. However, the application target of the present invention is not intended to be limited to such a battery. Absent. For example, the present invention can be applied to a non-aqueous electrolyte secondary battery using a metal ion other than lithium ion (for example, sodium ion) as a charge carrier. In the present specification, “secondary battery” generally refers to a battery that can be repeatedly charged and discharged. In addition to a storage battery such as a lithium ion secondary battery (that is, a chemical battery), a capacitor such as an electric double layer capacitor (that is, a physical battery). Battery). Further, in the present specification, the “lithium ion secondary battery” refers to a secondary battery that uses lithium ions as electrolyte ions and is charged and discharged by the movement of charges accompanying the lithium ions between the positive and negative electrodes.

  As shown in FIG. 1, the lithium ion secondary battery 10 has a configuration in which an electrode body 11 is accommodated in a battery case 15 together with a non-aqueous electrolyte 20. The electrode body 11 includes a positive electrode 12, a negative electrode 14, and a separator 13. At least a part of the nonaqueous electrolytic solution 20 is impregnated in the electrode body 11.

  The positive electrode 12 includes a long sheet-like positive electrode current collector 122 and a positive electrode mixture layer 124 that includes a positive electrode active material and is provided on the positive electrode current collector 122. The negative electrode 14 includes a long sheet-like negative electrode current collector 142 and a negative electrode mixture layer 144 that includes a negative electrode active material and is provided on the negative electrode current collector 142. Like the positive electrode 12 and the negative electrode 14, the separator 13 is formed in a long sheet shape. The positive electrode 12 and the negative electrode 14 are wound in a cylindrical shape together with the two separators 13 so that the separator 13 is interposed therebetween. The shape of the electrode body 11 after winding is not limited to a cylindrical shape. For example, after the positive electrode 12, the separator 13, and the negative electrode 14 are wound, a flat shape may be formed by applying a force from the side. In addition, the shapes of the positive electrode current collector 122 and the negative electrode current collector 142 may vary depending on the shape of the lithium ion secondary battery, and thus are not particularly limited, and include various shapes such as a rod shape, a plate shape, a foil shape, and a mesh shape. It may be a form.

  The battery case 15 includes a bottomed cylindrical case main body 152 and a lid 154 that closes an opening of the case main body 152. The lid 154 and the case main body 152 are both made of metal and insulated from each other. The lid 154 is electrically connected to the positive electrode current collector 122, and the case body 152 is electrically connected to the negative electrode current collector 142. In the lithium ion secondary battery 10, the lid 154 also serves as a positive terminal and the case body 152 serves as a negative terminal.

  On one edge (upper edge in FIG. 1) along the longitudinal direction of the positive electrode current collector 122, a portion where the positive electrode current collector 122 is exposed without the positive electrode mixture layer 124 being formed is formed. A lid 154 is electrically connected to the exposed portion. On one edge along the longitudinal direction of the negative electrode current collector 142 (lower edge in FIG. 1), a portion where the negative electrode current collector 142 is exposed without the negative electrode mixture layer 144 being formed. The case main body 152 is electrically connected to the exposed portion.

  As shown in FIG. 2, the separator 13 includes a porous resin layer 60 and a porous filler layer 70 formed on the surface of the resin layer 60. In this embodiment, the resin layer 60 has a three-layer structure, but the number of layers in the multilayer structure is not limited to three, and may be two or four or more. As shown in FIG. 3, the resin layer 60 may have a single layer structure. For example, in the case of using a solid (gel-like) electrolyte in which a polymer is added to the electrolytic solution instead of the electrolytic solution, the resin layer 60 becomes unnecessary (that is, in this case, the electrolyte itself is It can function as the resin layer 60). That is, in the said embodiment, although the filler layer is formed on the separator, it is not restricted to this form, As long as a desired function can be expressed, the formation position of a filler layer changes between a positive electrode and a negative electrode. be able to. For example, in the separatorless battery described above, the filler layer can be provided on a solid (gel) electrolyte.

  The constituent elements constituting such an electrode body may be the same as those of a conventional lithium ion secondary battery except for a filler layer described later, and there is no particular limitation. For example, a conductive member made of a highly conductive metal is preferably used for the positive electrode current collector. For example, aluminum or an alloy containing aluminum as a main component can be used. In addition to the positive electrode active material, the positive electrode mixture layer can contain additives such as a conductive material and a binder (binder) as necessary.

As the positive electrode active material, a material capable of inserting and extracting lithium is used, and one or more of materials conventionally used in lithium ion secondary batteries can be used without any particular limitation. For example, a composite oxide containing lithium and at least one transition metal element (preferably at least one of nickel, cobalt, and manganese) can be given. For example, so-called one-component lithium-containing composite oxides containing one kind of transition metal element, such as cobalt lithium composite oxide, nickel lithium composite oxide, manganese lithium composite oxide; nickel-cobalt-based, cobalt-manganese-based, nickel- So-called binary lithium-containing composite oxides containing two kinds of transition metal elements such as manganese series; ternary lithium transition metal oxides containing nickel, cobalt and manganese as constituent elements as transition metal elements; solid solution type lithium An excess transition metal oxide or the like is preferably used. Of these, ternary lithium transition metal oxides containing nickel, cobalt and manganese as transition metal elements are more preferred. As the positive electrode active material, the general formula is LiMAO ₄ (where M is at least one metal element selected from the group consisting of Fe, Co, Ni and Mn, and A is P, Si, S and A polyanionic compound represented by the above is an element selected from the group consisting of V. The ratio of the positive electrode active material to the positive electrode mixture layer is preferably more than about 50% by mass, and preferably about 70% to 95% by mass (for example, 75% to 90% by mass).

  As the conductive material, a conductive powder material such as carbon powder or carbon fiber is preferably used. As the carbon powder, various carbon blacks such as acetylene black, furnace black, ketjen black, and graphite powder are preferable. In addition, conductive fibers such as carbon fibers and metal fibers, metal powders such as copper and nickel, and organic conductive materials such as polyphenylene derivatives may be included singly or as a mixture of two or more. it can. Examples of the binder include various polymer materials. For example, when the positive electrode mixture layer is formed using an aqueous liquid composition (a composition using water or a mixed solvent containing water as a main component as a dispersion medium of active material particles), water is used as the binder. A polymer material that dissolves or disperses in water can be preferably used. Examples of the water-soluble (water-soluble) polymer material include cellulose polymers such as carboxymethyl cellulose (CMC); polyvinyl alcohol (PVA); Examples of polymer materials that can be dispersed in water (water-dispersible) include fluorine resins such as polytetrafluoroethylene (PTFE); vinyl acetate copolymers; styrene butadiene rubber (SBR), acrylic acid-modified SBR resins (SBR). Rubbers such as latex). Alternatively, when the positive electrode mixture layer is formed using a solvent-based liquid composition (a composition in which the dispersion medium of active material particles is mainly an organic solvent), polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC) Polymer materials such as vinyl halide resins such as); polyalkylene oxides such as polyethylene oxide (PEO); and the like can be used. Such a binder may be used alone or in combination of two or more. In addition, the polymer material illustrated above may be used as a thickener and other additives in the composition for forming a positive electrode mixture layer, in addition to being used as a binder. The ratio of these additives in the positive electrode mixture layer is not particularly limited, but the ratio of the conductive material is preferably about 4% by mass to 20% by mass (for example, 4% by mass to 18% by mass). The ratio of the material is preferably about 1% by mass to 10% by mass (for example, 1% by mass to 7% by mass).

  The method for producing the positive electrode as described above is not particularly limited, and a conventional method can be adopted. For example, it can be produced by the following method. First, a positive electrode active material, a conductive material, a binder, and the like are mixed with an appropriate solvent (aqueous solvent, non-aqueous solvent, or a mixed solvent thereof) to form a paste or slurry-like composition for forming a positive electrode mixture layer ( Hereinafter, it is also referred to as a paste-like composition). The mixing operation can be performed using, for example, an appropriate kneader (planetary mixer, homodisper, clear mix, fill mix, etc.). As a solvent used for preparing the paste composition, both an aqueous solvent and a non-aqueous solvent can be used. As described above, the aqueous solvent only needs to be water-based as a whole, that is, water or a mixed solvent mainly composed of water can be preferably used. Further, preferred examples of the non-aqueous solvent include N-methyl-2-pyrrolidone (NMP), methyl ethyl ketone, toluene and the like. The paste-like composition thus prepared is applied to the positive electrode current collector, the solvent is volatilized and dried, and then compressed (pressed). As a method of applying the paste composition to the positive electrode current collector, a technique similar to a conventionally known method can be appropriately employed. For example, the composition can be suitably applied to the positive electrode current collector by using an appropriate application device such as a slit coater, a die coater, a gravure coater, or a comma coater. Moreover, when drying a solvent, it can dry favorably by using natural drying, a hot air, low-humidity air, a vacuum, infrared rays, far infrared rays, and an electron beam individually or in combination. Furthermore, as a compression method, a conventionally known compression method such as a roll press method or a flat plate press method can be employed. In adjusting the thickness, the thickness may be measured with a film thickness measuring instrument, and the compression may be performed a plurality of times until the desired thickness is obtained by adjusting the press pressure. Thus, the positive electrode of the lithium ion secondary battery in which the positive electrode mixture layer is formed on the positive electrode current collector is obtained.

For example, in the positive electrode produced as described above, the basis weight per unit area of the positive electrode mixture layer on the positive electrode current collector (the coating amount in terms of solid content of the positive electrode mixture layer forming composition) is: sufficient conductive path is not particularly restricted so long as it can be ensured (conductive path), 5 mg / cm ² or more (e.g., 7 mg / cm ² or more, typically 9.8 mg / cm ² or higher) in and, 100 mg / cm ² or less (e.g., 50 mg / cm ² or less, typically 15.2 mg / cm ² or less) is preferably set to. Further, the density of the positive electrode mixture layer is not particularly limited, but is 1.0 g / cm ³ or more (for example, 1.5 g / cm ³ or more, typically 1.8 g / cm from the viewpoint of improving the permeability of the electrolytic solution). ³ or more), preferably 3.5 g / cm ³ or less (eg, 3.0 g / cm ³ or less, typically 2.4 g / cm ³ or less).

For the negative electrode current collector constituting the negative electrode, a conductive member made of a metal having good conductivity is preferably used. For example, copper or an alloy containing copper as a main component can be used. The negative electrode mixture layer provided on the negative electrode current collector contains a negative electrode active material capable of inserting and extracting lithium ions serving as charge carriers. The composition and shape of the negative electrode active material are not particularly limited, and one or more materials conventionally used in lithium ion secondary batteries can be used. Examples of the negative electrode active material include carbon materials used in typical lithium ion secondary batteries. Representative examples of the carbon material used as the negative electrode active material include graphite carbon (graphite) and amorphous carbon. Among these, a particulate carbon material (carbon particles) including a graphite structure (layered structure) at least partially is preferably used. Also, any carbon material of a so-called graphitic material (graphite), a non-graphitizable carbonaceous material (hard carbon), a graphitizable carbonaceous material (soft carbon), or a combination of these is suitable. Can be used. Among these, it is preferable to use a carbon material mainly composed of natural graphite (or artificial graphite). Such natural graphite (or artificial graphite) may be obtained by spheroidizing graphite. As the graphite particles containing the spheroidized graphite, for example, a median diameter (average particle diameter D ₅₀ : 50% volume average particle diameter) that can be derived from a particle size distribution measured based on a particle size distribution measuring apparatus based on a laser scattering / diffraction method. What is in the range of about 5 micrometers-30 micrometers can be used preferably. Further, a carbonaceous powder in which amorphous carbon is coated on the surface of the graphite can also be preferably used. In addition, as the negative electrode active material, it is also possible to use oxides such as lithium titanate (LTO), simple substances such as silicon materials and tin materials, alloys, compounds, and composite materials using the above materials in combination. The proportion of the negative electrode active material in the negative electrode mixture layer exceeds approximately 50% by mass, and is approximately 90% to 99% by mass (for example, 95% to 99% by mass, typically 97% to 99% by mass). It is preferable that In addition to the negative electrode active material, the negative electrode mixture layer may contain additives such as a binder (binder), a thickening material, and other additives similar to those of the positive electrode mixture layer as necessary. The ratio of these additives in the negative electrode mixture layer is not particularly limited, but is approximately 1% by mass to 10% by mass (for example, approximately 1% by mass to 5% by mass, typically 1% by mass to 3% by mass). Preferably there is.

  The method for producing the negative electrode as described above is not particularly limited, and a conventional method can be adopted. For example, it can be produced by the following method. First, the negative electrode active material is mixed with the above-mentioned appropriate solvent (aqueous solvent, organic solvent or a mixed solvent thereof) together with a binder or the like, and a paste-form or slurry-form composition for forming a negative electrode mixture layer (hereinafter, (Also referred to as a paste-like composition). The paste-like composition thus prepared is applied to the negative electrode current collector, the solvent is volatilized and dried, and then compressed (pressed). Thus, a negative electrode of a lithium ion secondary battery provided with a negative electrode mixture layer formed using the paste-like composition on a negative electrode current collector is obtained. In addition, conventionally well-known means can be used for the mixing, application | coating, drying, and compression method similarly to the preparation method of the above-mentioned positive electrode.

For example, in the negative electrode produced as described above, the basis weight per unit area of the negative electrode mixture layer on the negative electrode current collector (the coating amount in terms of solid content of the negative electrode mixture layer forming composition) is: Although not particularly limited as long as a sufficient conductive path (conductive path) can be secured, it is 2.5 mg / cm ² or more (for example, 3 mg / cm ² or more, typically 4.8 mg / cm ^2). is higher), 50 mg / cm ² or less (e.g., 25 mg / cm ² or less, typically it is preferable to 10.2 mg / cm ² or less). Further, the density of the negative electrode mixture layer is not particularly limited, but from the viewpoint of improving the permeability of the electrolytic solution, it is 0.5 g / cm ³ or more (for example, 0.7 g / cm ³ or more, typically 0.8 g / cm ³ or more), preferably 2.5 g / cm ³ or less (for example, 2.0 g / cm ³ or less, typically 1.4 g / cm ³ or less).

  As the non-aqueous electrolyte, a non-aqueous electrolyte conventionally used in lithium ion secondary batteries can be used without any particular limitation. Such a nonaqueous electrolytic solution typically has a composition in which a supporting salt is contained in a suitable nonaqueous solvent. Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), 1,2-dimethoxyethane, 1,2 -Diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, propionitrile, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, γ-butyrolactone These may be used alone or in combination of two or more.

Examples of the supporting salt include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ). ₃ , 1 type or 2 types or more of lithium compounds (lithium salt), such as LiI, can be used. In addition, the density | concentration of support salt may be the same as that of the nonaqueous electrolyte solution used with the conventional lithium ion secondary battery, and there is no restriction | limiting in particular. A suitable lithium compound (supporting salt) at a concentration of about 0.1 mol / L to 5 mol / L (eg 0.5 mol / L to 3 mol / L, typically 0.8 mol / L to 1.5 mol / L). The contained nonaqueous electrolyte solution can be used.

  As a material for the resin layer having a single layer or a multilayer structure, for example, a polyolefin-based resin such as polyethylene (PE) or polypropylene (PP) can be suitably used. For example, in the case of a PE resin, the polyolefin resin is preferably an ethylene homopolymer, containing more than 50% by weight of repeating units derived from ethylene, and containing at least one monomer copolymerizable with ethylene. A polymerized copolymer may be used. For example, the resin layer 60 shown in FIG. 2 is composed of a PP layer 61, a PE layer 62 laminated on the PP layer 61, and a PP layer 63 laminated on the PE layer 62. Further, the resin layer 60 having a single layer structure shown in FIG. 3 is composed of, for example, only the PE layer 62.

   As the resin layer, for example, a uniaxially or biaxially stretched porous resin film can be suitably used. Among these, a porous resin film uniaxially stretched in the longitudinal direction is particularly preferable because it has an appropriate strength and has little heat shrinkage in the width direction. When a separator having a uniaxially stretched porous resin film is used, thermal contraction in the longitudinal direction can be suppressed in a mode in which the separator is wound together with a long sheet-like positive electrode and negative electrode. Therefore, the porous resin film uniaxially stretched in the longitudinal direction is particularly suitable as one element of the separator constituting such a wound electrode body.

  The thickness of the resin layer is not particularly limited, but is preferably about 5 μm to 30 μm (for example, 10 μm to 30 μm, typically 15 μm to 25 μm). When the thickness of the resin layer is within the above range, the ion conductivity of the separator becomes better, and film breakage is less likely to occur. The thickness of the resin layer can be obtained by image analysis of an image taken with a scanning electron microscope (SEM).

The porosity of the resin layer is not particularly limited, but is 20% or more (for example, 30% or more, typically 35% or more) from the viewpoint of holding a sufficient amount of electrolyte and further improving ion conductivity. It is preferable. Further, the porosity is not more than 60% (for example, not more than 55%, typically not more than 50%) from the viewpoint of easily adjusting the elongation rate of the resin layer to a suitable range and obtaining a strength that does not cause film breakage. ) Is preferable. The porosity of the resin layer can be calculated as follows. The apparent volume occupied by the resin layer of the unit area (surface area) is V1 [cm ³ ], and the mass of the resin layer of the unit area is W [g]. The ratio between the mass W and the true density ρ [g / cm ³ ] of the resin material constituting the resin layer, that is, W / ρ is V0. V0 is the volume occupied by the dense body of the resin material with mass W. At this time, the porosity of the resin layer can be calculated by [(V1-V0) / V1] × 100.

The filler layer has the general formula:
Al ₂ O _3. (H ₂ O) _x
A filler (filler) substantially composed of an inorganic material represented by the formula (where x satisfies 0 ≦ x ≦ 2) is included as a main component. Examples of the inorganic material represented by the general formula include boehmite (in the general formula, 1 ≦ x ≦ 2) and alumina (in the general formula, 0 ≦ x <1). As alumina, α alumina (in the above general formula, x = 0), γ alumina, χ alumina, η alumina (above, in the above general formula, x = 0.12), δ alumina, κ alumina (above, the above general In the formula, x = 0.07) and θ-alumina (in the above general formula, x = 0.02) can be mentioned. These can be used individually by 1 type or in mixture of 2 or more types. Especially, it is preferable to use boehmite for the reason that it is excellent in heat resistance.

  The inorganic material used in the practice of the present invention is an X-ray peak intensity ratio of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα) when 1 ≦ x ≦ 2 in the general formula. It is preferable that I (020) / I (120) is 5 to 200. In the general formula, the X-ray peak intensity ratio I (020) / I (120) of the inorganic material when 1 ≦ x ≦ 2 is preferably 35 or more (for example, 50 or more, typically 100 or more). 150 or less (for example, 100 or less, typically 50 or less). When the X-ray peak intensity ratio of the inorganic material represented by the above general formula is 5 or more, the initial capacity of the battery is increased, and the effect of reducing battery resistance by containing S is sufficiently obtained. As one of the reasons, the specific surface area of the filler substantially composed of the inorganic material is reduced by the X-ray peak intensity ratio being 5 or more, and Na present in the filler surface in the unit mass of the filler is reduced. Since the amount of water also decreases, the amount of moisture adsorbed by Na decreases, and as a result, S contained in a predetermined amount can sufficiently react with Na, preventing water from being mixed into the battery due to Na, It is assumed that the increase in battery resistance due to the mixing of moisture is prevented and the decrease in battery capacity is suppressed. In addition, when the X-ray peak intensity ratio of the inorganic material represented by the above general formula is 200 or less, lithium (Li) ions that are charge carriers can easily pass through the filler layer, thereby reducing battery resistance. it can.

  Alternatively, as the inorganic material used in the practice of the present invention, when the general formula satisfies 0 ≦ x <1, the X-ray peak intensity of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα) The ratio I (116) / I (110) is preferably 5 to 200. The X-ray peak intensity ratio I (116) / I (110) is 35 or more (for example, 50 or more, typically, for the same reason as the case of the X-ray peak intensity ratio I (020) / I (120)). Is preferably 100 or less, and is preferably 150 or less (for example, 100 or less, typically 50 or less). The reason is the same as that in the case of the X-ray peak intensity ratio I (020) / I (120) of the inorganic material in the case where 1 ≦ x ≦ 2 in the above-described general formula, and the description will not be repeated.

  The filler also contains sodium (Na) and sulfur (S) as minor components. Na and S are contained in the filler manufacturing process and the like, which can be understood by referring to, for example, JP-A-2001-19424. For reference, the amount of Na in the filler is, for example, about 300 ppm to 2000 ppm on a mass basis when boehmite or alumina is produced based on the method disclosed in JP-A-2001-19424, and 5 ppm for alumina. ~ 250 ppm.

  The content of S contained in the filler as a trace component is at least 10 ppm on a mass basis, and preferably 20 ppm or more (for example, 25 ppm or more). When the content of S is 10 ppm or more, S reacts sufficiently with Na contained in the filler in the production process or the like. By this reaction, S and Na are combined, and Na in the filler adsorbs water and prevents moisture from being brought into the battery. Thereby, the generation of impurities (typically hydrogen fluoride (HF)) due to the reaction between the moisture and the non-aqueous electrolyte (typically, the supporting salt in the non-aqueous electrolyte) is suppressed. As a result, an increase in battery resistance due to such impurities is prevented, and a decrease in battery capacity is suppressed. The upper limit of the S content in the filler is not particularly limited, but is an amount that does not adversely affect the properties required for the filler layer (for example, heat resistance) and does not decrease the initial capacity of the battery, for example, about 1000 ppm or less on a mass basis. It is preferably 500 ppm or less (for example, 100 ppm or less, typically 50 ppm or less). In addition, although the measuring method of S content in a filler is not specifically limited, For example, a carbon sulfur analyzer (for example, CS-444 etc. by LECO), an element analyzer using flash combustion (for example, CHSN by LECO, USA) 932), an energy dispersive X-ray analyzer (for example, JED-2200 manufactured by JEOL Ltd.).

  The content of the inorganic material substantially constituting the filler in the filler is, for example, about 95% by mass or more, preferably 98% by mass or more (for example, 99% by mass or more, typically 99.5% by mass or more). It is. The content of the trace component in the filler is, for example, about 1% by mass or less (for example, 0.5% by mass or less, typically 0.3% by mass or less). Although the minimum of content of a trace component is not specifically limited, It is about 20 ppm or more on a mass basis.

The form of the filler (inorganic material) is not particularly limited, and may be in the form of particles, fibers, plates (flakes), or the like. The average particle size of the filler (inorganic material) is preferably, for example, 0.15 μm to 2 μm (for example, 0.2 μm to 1.8 μm). The specific surface area of the filler (inorganic material), for example, ^2m 2 / (typically ^{2.8m 2 / g~100m 2 / g)} g~100m 2 / g may be on the order. In this specification, the “average particle diameter” means a median diameter (average particle diameter D ₅₀ : 50% volume average particle diameter) that can be derived from a particle size distribution measured based on a particle size distribution measuring apparatus based on a laser scattering / diffraction method. It shall be.

Such a filler can be prepared and provided by a conventionally known method, for example. Although the preparation method is not specifically limited, For example, the following method is mentioned. First, bauxite containing approximately 40% by mass to 60% by mass of alumina is prepared, and this bauxite is put into a sodium hydroxide solution at about 250 ° C. In this process, alumina has the following formula:
Al ₂ O ₃ + 2OH ⁻ + 3H ₂ O → 2 [Al (OH) ₄ ] ⁻
And the above solution becomes a sodium aluminate solution. By filtering this solution, other components (for example, silica, iron oxide, titania) that do not dissolve in the solution in bauxite are removed. By washing bauxite with the sodium hydroxide solution (removing other components) in this way, a sodium aluminate solution from which impurities have been removed is obtained. Aluminum hydroxide is produced from this sodium aluminate solution, for example, by the method disclosed in JP-A-2001-19424. In this method, an alumina gel is obtained by mixing 0.4 mol times to 0.6 mol times of an aluminum sulfate solution (SO ₄ ²⁻ ) with respect to a sodium aluminate solution (N ₂ O equivalent). This is added to a sodium aluminate solution as a seed and crystallized to produce aluminum hydroxide. By putting the aluminum hydroxide thus prepared into a hot aqueous solution of about 200 ° C., one molecule of water is desorbed (dehydrated), and boehmite (Al ₂ O ₃ .H ₂ O) is obtained. Or the said sodium hydroxide is heated at high temperature (temperature higher than 200 degreeC), and an alumina produces | generates by making it dehydrate. Various aluminas can be obtained by appropriately changing the heating temperature. In the case of α alumina, the heating temperature is about 1050 ° C., in the case of χ alumina and η alumina, the heating temperature is about 250 ° C. to 300 ° C., and in the case of δ alumina and κ alumina, the heating temperature is 800 ° C. In the case of θ alumina, the heating temperature is about 900 ° C. γ-alumina can be obtained by heat treating boehmite at a temperature of about 500 ° C.

  For example, the boehmite and alumina obtained as described above have conventionally used impurities removed by washing or the like. As a result of this water washing, a certain amount of Na was removed, and S was less than 10 ppm (typically less than 1 ppm) in terms of mass in the filler as shown in the description of Examples below. Therefore, in the present invention, the S content in the filler is adjusted to be at least 10 ppm on a mass basis so as to be qualitatively different from the conventionally used filler. Although the adjustment method of S content in a filler is not specifically limited, For example, it is possible to adjust S content in a filler by adjusting the grade of the produced boehmite and the water washing of an alumina. Moreover, when S content in a filler is less than 10 ppm, it can adjust so that S content in a filler may increase by the acid treatment using a sulfuric acid etc. Further, for example, the S content in the filler can be adjusted by adjusting the amount of S added at the time of manufacturing the filler described above. The selection of a filler containing a predetermined amount of S obtained by such a method is also included in the present specification by adjusting the S content of the filler to at least 10 ppm on a mass basis.

  Also, the method for adjusting the X-ray peak intensity ratio of the inorganic material is not particularly limited. For example, the X-ray peak intensity ratio of the inorganic material can be adjusted by appropriately setting the firing temperature and firing time during filler production, or by appropriately setting the type and amount of additive components such as aluminum sulfate. it can. In addition, in the present specification, it is also possible to select a filler substantially composed of an inorganic material having a predetermined X-ray peak intensity ratio obtained by such a method. It is included in adjusting.

  The filler layer preferably also contains a binder. The binder is dispersed or dissolved in an aqueous solvent when the filler layer forming composition described later is an aqueous solvent (a solution using water or a mixed solvent containing water as a main component as a binder dispersion medium). Polymers can be used. Examples of the polymer that is dispersed or dissolved in the aqueous solvent include acrylic resins. Acrylic resins include acrylic acid, methacrylic acid, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, 2-ethylhexyl acrylate and butyl acrylate. Coalescence is preferably used. The acrylic resin may be a copolymer obtained by polymerizing two or more of the above monomers. Further, a mixture of two or more of the above homopolymers and copolymers may be used. In addition to the acrylic resin described above, styrene butadiene rubber (SBR), acrylic acid-modified SBR resin (SBR latex), rubber such as gum arabic; polyolefin resin such as polyethylene (PE); carboxymethylcellulose (CMC), Cellulose polymers such as methylcellulose (MC), cellulose acetate phthalate (CAP), hydroxypropylmethylcellulose (HPMC), hydroxypropylmethylcellulose phthalate (HPMCP); polyvinyl alcohol (PVA); polytetrafluoroethylene (PTFE), tetrafluoroethylene -Perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer Fluorine-based resin such as ETFE; vinyl acetate copolymer; polyalkylene oxide such as polyethylene oxide (PEO), polypropylene oxide (PPO), ethylene oxide-propylene oxide copolymer (PEO-PPO); etc. be able to. These polymers can be used alone or in combination of two or more. Of these, acrylic resins, SBR, and polyolefin resins are preferable. These water-based binders are preferable in that they do not react and harden with moisture in the atmosphere and can easily adjust the extensibility of the filler layer (for example, without performing water management during production).

  In addition, when the filler layer forming composition to be described later is a solvent-based solvent (a solution in which the binder dispersion medium is mainly an organic solvent), the binder is a polymer that is dispersed or dissolved in the solvent-based solvent. Can do. Examples of the polymer dispersed or dissolved in the solvent-based solvent include vinyl halide resins such as polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC). As the polyvinylidene fluoride, a homopolymer of vinylidene fluoride is preferably used. Furthermore, as the polyvinylidene fluoride, a copolymer of a vinyl monomer copolymerizable with vinylidene fluoride is also preferably used. Examples of vinyl monomers copolymerizable with vinylidene fluoride include hexafluoropropylene, tetrafluoroethylene, and ethylene trichloride fluoride. Alternatively, polytetrafluoroethylene (PTFE), polyacrylonitrile, polymethyl methacrylate, or the like is preferably used as a polymer that is dispersed or dissolved in a solvent-based solvent. You may use these individually by 1 type or in combination of 2 or more types. These solvent-based binders are preferable in that the extensibility of the filler layer can be suitably improved. However, since the solvent-based binder reacts with moisture in the atmosphere and cures, it is necessary to perform moisture management during production.

  The form of the binder is not particularly limited, and a particulate (powdered) form may be used as it is, or a solution prepared in the form of a solution or an emulsion may be used. Two or more binders may be used in different forms. In the case of using a particulate binder, the average particle diameter is, for example, about 0.09 μm to 0.15 μm. In addition, the binder illustrated above may be used for the purpose of exhibiting a function as a thickener or other additive of the filler layer forming composition in addition to the function as a binder.

  The proportion of the filler in the entire filler layer is not particularly limited, but is approximately 90% by mass or more (for example, 95% by mass to 99.5% by mass, typically 97% by mass to 99% by mass). Is preferred. When the filler layer contains a binder, the proportion of the binder in the filler layer can be about 7% by mass or less, and about 5% by mass or less (for example, 0.5% by mass to 5% by mass, typically Is preferably 1% by mass to 3% by mass). Further, when a filler layer forming component other than the filler and the binder (for example, a thickener, etc., hereinafter also referred to as other additive components) is contained, the total content of the other additive components is approximately 3% by mass or less (for example, 2 mass% or less, typically 0.5 mass% to 1 mass%). When the proportion of the filler, if necessary, the binder and other additive components is within the above range, the elongation percentage of the separator can be easily adjusted to a suitable range, and the anchoring property of the filler layer and the strength of the filler layer itself (maintenance can be maintained. (Shape) can be further improved, and sufficient porosity is obtained by the filler layer, and the ion permeability of the separator including the filler layer tends to be further improved.

  The thickness of the filler layer is preferably about 1 μm to 12 μm, and more preferably about 2 μm to 8 μm. When the thickness of the filler layer is within the above range, the elongation percentage of the separator can be easily adjusted to a more suitable range, the short-circuit preventing effect is excellent, and the electrolytic solution tends to be held more suitably. . The thickness of the filler layer can be obtained by image analysis of an image taken with a scanning electron microscope (SEM).

  The porosity of the filler layer is not particularly limited, but is 40% or more (for example, 45% or more, typically 50% or more) from the viewpoint of further improving the ion conductivity of the separator and further improving the discharge characteristics. Is preferred. In addition, the porosity is 75% or less (for example, 70% or less, typically 65% from the viewpoint of suppressing thermal shrinkage of the resin layer and obtaining a strength that does not cause defects such as cracks and peeling off). Or less). The porosity of the filler layer can be calculated by the same method as the calculation of the porosity of the resin layer. In that case, the mass W of the filler layer can be measured as follows. That is, a separator is cut out to a predetermined area to obtain a sample, and its mass is measured. Next, the mass W of the filler layer having the predetermined area is calculated by subtracting the mass of the resin layer having the predetermined area from the mass of the sample. The mass W [g] of the filler layer can be calculated by converting the mass of the filler layer thus calculated per unit area.

  Although the average pore diameter of the pores constituting the pores of the filler layer is not particularly limited, for example, it may be in the range of 0.01 μm to 10 μm, or may be in the range of 0.1 μm to 4 μm. The average pore diameter can be measured using a commercially available mercury porosimeter or the like.

  The method for forming such a filler layer is not particularly limited. The filler layer can be formed, for example, by the following method. First, the above-described filler, if necessary, a binder and other additive components are mixed and dispersed in an appropriate solvent to prepare a paste-like (or slurry-like) filler layer forming composition. Mixing and dispersing operations can be performed using an appropriate kneader such as a disper mill, a clear mix, a fill mix, a ball mill, a homodisper, or an ultrasonic disperser. The blending ratio of the obtained paste-like (or slurry-like) filler layer-forming composition, if necessary, the binder and other additive components is the ratio of each component in the filler layer described above in terms of solid content. The same can be done.

  Examples of the solvent used in the composition for forming a filler layer include water or a mixed solvent mainly composed of water. As the solvent other than water constituting the mixed solvent, one or more organic solvents (lower alcohols such as ethanol, lower ketones, etc.) that can be uniformly mixed with water can be appropriately selected and used. Alternatively, one organic solvent such as N-methyl-2-pyrrolidone (NMP), pyrrolidone, methyl ethyl ketone, methyl isobutyl ketone, ixahexanone, toluene, dimethylformamide, dimethylacetamide, or a combination of two or more organic solvents. It may be used. Although the content rate of the solvent in the composition for filler layer formation is not specifically limited, It is 30 mass%-90 mass% (for example, 40 mass%-60 mass%) of the whole composition.

  Next, an appropriate amount of the obtained paste-like (or slurry-like) filler layer-forming composition is applied to the surface of the resin layer and further dried to form a filler layer. The operation of applying the filler layer forming composition to the surface of the resin layer can be used without any particular limitation on conventional general application means. For example, using a suitable coating apparatus (gravure coater, slit coater, die coater, comma coater, dip coat, etc.), a predetermined amount of the filler layer forming composition is uniformly applied to at least one surface of the resin layer. Apply to a proper thickness. Thereafter, the coated material is dried (for example, at a temperature lower than the melting point of the resin layer, for example, 110 ° C. or less (typically 30 to 80 ° C.)) by an appropriate drying means, whereby the filler layer forming composition contains Remove the solvent. Or you may hold | maintain under low temperature pressure reduction, and may make it dry. By removing the solvent from the filler layer forming composition, a filler layer containing the filler as a main component can be formed. In this way, a sheet-like separator having a filler layer formed on at least one surface of the resin layer can be obtained.

  The lithium ion secondary battery using the filler layer described above is manufactured, for example, by the following method. With reference to FIG. 1, first, the positive electrode 12, the separator 13, and the negative electrode 14 mentioned above are respectively prepared and prepared. Next, the wound electrode body 11 in which the filler layer 70 is disposed between the positive electrode 12 and the negative electrode 14 is assembled by overlapping them and winding them into a cylindrical shape. The electrode body 11 is inserted into the case main body 152, and the nonaqueous electrolytic solution 20 is injected into the case main body 152. As a result, the electrode body 11 is impregnated with the nonaqueous electrolytic solution 20. Thereafter, the case body 152 is covered with the lid body 154, and the lid body 154 and the case body 152 are sealed, whereby the lithium ion secondary battery 10 can be constructed. The method for sealing case body 152 and the method for injecting electrolyte are not particularly limited, and a method similar to the method used in the manufacture of conventional lithium ion secondary batteries can be employed.

  As described above, the lithium ion secondary battery constructed in this manner has low battery resistance and is excellent in suppressing capacity reduction, and thus can be used as a secondary battery for various applications. For example, as shown in FIG. 4, the lithium ion secondary battery 10 is mounted on a vehicle 1 such as an automobile and can be suitably used as a power source for a drive source such as a motor that drives the vehicle 1. Therefore, the present invention provides a vehicle (typically an automobile, particularly a hybrid automobile, an electric automobile, a fuel cell automobile) provided with the lithium ion secondary battery (typically, a plurality of battery packs connected in series) 10 as a power source. An automobile equipped with such an electric motor) 1 can be provided.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<Examples 1, 3, 4 and 7>
(Preparation of separator with filler layer)
A long sheet-like three-layer film (PP / PE / PP film) made of polypropylene / polyethylene / polypropylene having a thickness of 20 μm and a porosity of 48% was used as a resin layer. The porosity of this resin layer was 48%. As a filler, the amount of sulfur (S) shown in Table 1 is contained, and the X-ray peak intensity ratio I (020) / I (120) obtained by wide-angle X-ray diffraction spectrum (CuKα) is the value shown in Table 1. Various boehmite (general formula:
Al ₂ O _3. (H ₂ O) _x
(Wherein x satisfies 1 ≦ x ≦ 2)). In addition, these boehmites are dried after washing with water to remove impurities. Each prepared boehmite, an acrylic binder as a binder, and CMC (“BSH6” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a thickener have a solid content mass ratio of 98: 1.3: 0.7. In addition, ion-exchanged water is added so that the solid content (NV) is 50% by mass, and the mixture is kneaded with a kneader (ultrasonic disperser “CLEAMIX” manufactured by M Technique Co., Ltd.), and pasty filler A layer forming composition was prepared. For kneading, preliminary dispersion was performed at 15000 rpm for 5 minutes, and main dispersion was performed at 20000 rpm for 15 minutes. The average particle size of the boehmite is in the range of 0.2Myuemu～1.8Myuemu, its specific surface area was in the range of 2.8m ² / g~100m ² / g. One side of the resin layer was formed by a gravure coating method using a gravure roll (art (number of lines # 100 / inch, cell volume 19.5 cc / m ² )) using the obtained paste-like filler layer forming composition. And dried at a temperature of 70 ° C. to form a filler layer. In the gravure coating, the line speed of the resin sheet was 3 m / min, the gravure roll speed was 3.8 m / min, and the speed ratio (gravure speed / line speed) was 1.27. The thickness of the filler layer after drying was 4 μm, and the porosity of the filler layer was 55%. The obtained sheet-like separator was wound up in a roll shape to produce a separator roll composed of a separator with a filler layer. In addition, S content in a filler layer is the value measured with the carbon sulfur analyzer (CS-444 by LECO).

(Preparation of positive electrode sheet)
As a positive electrode active material, lithium nickel manganese cobaltate (Li [Ni _1/3 Mn _1/3 Co _1/3 O ₂ ) powder, acetylene black as a conductive material, and polyvinylidene fluoride (PVDF) as a binder The paste-like positive electrode mixture layer is mixed in N-methyl-2-pyrrolidone (NMP) so that the mass ratio of these materials is 85: 10: 5 and the solid content is 56 mass%. A forming composition was prepared. This composition is uniformly formed in a strip shape so that the total basis weight is 12.5 mg / cm ² (solid content basis) on both surfaces of a positive electrode current collector (thickness 15 μm) composed of a long sheet-like aluminum foil. After coating and drying, a positive electrode mixture layer was formed on the positive electrode current collector by compression (pressing) to produce a sheet-like positive electrode (positive electrode sheet). The density of the positive electrode mixture layer after drying was 2.1 g / cm ³ , the thickness of the whole positive electrode sheet after pressing was 85 μm, the length of the positive electrode sheet was 225 mm, and the width was 52.5 mm.

(Preparation of negative electrode sheet)
Carbonaceous powder having amorphous carbon coated on the surface of graphite particles, styrene butadiene rubber (SBR) as a binder, and carboxymethyl cellulose (CMC) as a thickener, the mass ratio of these materials is 98: 1: 1. And a paste-like composition for forming a negative electrode mixture layer was prepared by dispersing in water so that the solid content was 39% by mass. This composition is uniformly formed in a strip shape so that the total basis weight is 7.5 mg / cm ² (solid content basis) on both surfaces of a negative electrode current collector (thickness 10 μm) composed of a long sheet-like copper foil. After coating and drying, a negative electrode mixture layer was formed on the negative electrode current collector by compression (pressing) to produce a sheet-like negative electrode (negative electrode sheet). The density of the negative electrode mixture layer after drying was 1.1 g / cm ³ , the thickness of the whole negative electrode sheet after pressing was 75 μm, the length of the negative electrode sheet was 295 mm, and the width was 57.5 mm.

(Construction of lithium ion secondary battery)
A wound electrode body was obtained by stacking them and winding them into a cylindrical shape so that the separators produced above were also arranged between the produced positive electrode sheet and negative electrode sheet. In that case, the separator was arrange | positioned so that the filler layer of a separator might oppose a negative electrode sheet. The wound electrode body thus obtained is housed in a 18650 type battery container together with a non-aqueous electrolyte (non-aqueous electrolyte), and the opening of the battery container is hermetically sealed, so that a lithium ion secondary battery ( A design capacity of 5.2 Ah) was constructed. As a non-aqueous electrolyte, 1.1 mol / L LiPF ₆ as a supporting salt in a mixed solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a mass ratio of 3: 4: 3. A non-aqueous electrolyte solution containing was used.

<Examples 2, 5 and 6>
A long sheet-like single layer film (PE film) made of polyethylene was used as the resin layer of the separator. Moreover, when constructing the wound electrode body, the separator was disposed so that the filler layer faced the positive electrode sheet. Others produced the separator with a filler layer similarly to Example 1, and constructed the lithium ion secondary battery.

<Examples 8, 9, 11-16 and 19>
As a filler, the amount of sulfur (S) shown in Table 1 is contained, and the X-ray peak intensity ratio I (020) / I (120) obtained by wide-angle X-ray diffraction spectrum (CuKα) is the value shown in Table 1. A separator with a filler layer was produced in the same manner as in Example 1 except that various boehmites were used, and a lithium ion secondary battery was constructed.

<Examples 10, 17 and 18>
As a filler, the amount of sulfur (S) shown in Table 1 is contained, and the X-ray peak intensity ratio I (020) / I (120) obtained by wide-angle X-ray diffraction spectrum (CuKα) is the value shown in Table 1. A separator with a filler layer was prepared in the same manner as in Example 2 except that some boehmite was used, and a lithium ion secondary battery was constructed.

[Measurement of battery resistance]
About each lithium ion secondary battery produced above, after adjusting SOC (State of Charge) to the state of 60%, sweeping the measurement frequency in the atmosphere of measurement temperature 25 degreeC, impedance measurement is carried out, Cole- DC resistance (Rs) (mΩ) was read from the Cole plot. The results are shown in Table 1.

[Measurement of initial capacity / design capacity]
Each lithium ion secondary battery was charged at a constant current of 1 C up to 4.1 V under a temperature condition of 25 ° C., and then charged at a constant voltage until the total charging time was 2 hours. After the CC-CV charged battery is held at 25 ° C. for 24 hours, it is discharged at a constant current of 1 C from 4.1 V to 3.0 V at 25 ° C., and then constant until the total discharge time is 2 hours. The battery was discharged with a voltage, the discharge capacity at this time was measured, and this was used as the initial capacity. Using this value, the following formula:
Initial capacity (Ah / g) / Design capacity (Ah / g) × 100
From the above, the initial capacity / design capacity (%) was calculated. The results are shown in Table 1.

  As shown in Table 1, Example 10 provided with a filler layer using boehmite having an S content of 10 ppm or more and an X-ray peak intensity ratio I (020) / I (120) of 5 to 200 as a filler. The lithium ion secondary battery of Example 18 had a battery resistance of 23.3 mΩ or less, and an initial capacity / design capacity ratio of 91% or more. On the other hand, Examples 1 to 9 including a filler layer using boehmite as a filler, the S content being less than 10 ppm, or the X-ray peak intensity ratio I (020) / I (120) being less than 5 or exceeding 200, The lithium ion secondary battery of Example 19 had a higher battery resistance (mΩ) and a lower initial capacity / design capacity ratio than the lithium ion secondary batteries of Examples 10 to 18. Thus, a lithium ion secondary battery including a filler layer using boehmite having an S content of 10 ppm or more and an X-ray peak intensity ratio I (020) / I (120) of 5 to 200 as a filler, It can be seen that an increase in battery resistance is suppressed and a high initial capacity can be obtained. Although not specifically shown in the examples, a lithium ion secondary constructed by using a three-layer film (PP / PE / PP film) as a resin layer and arranging a separator so that the filler layer faces the positive electrode sheet. The battery resistance of the battery showed substantially the same tendency as the battery resistance of the lithium ion secondary batteries of Examples 10 to 18 in which the separator was disposed so that the filler layer faced the negative electrode sheet.

<Example 20 to Example 22>
As a filler, instead of the boehmite of Example 1, an amount of sulfur (S) shown in Table 2 is contained, and an X-ray peak intensity ratio I (116) / I (110) obtained by a wide-angle X-ray diffraction spectrum (CuKα). ) Α-alumina (general formula:
Al ₂ O _3. (H ₂ O) _x
(Inorganic material represented by the above formula, x = 0) was used. Others produced the separator with a filler layer similarly to Example 1, and constructed the lithium ion secondary battery. For the obtained lithium ion secondary battery, the battery resistance (mΩ) was measured in the same manner as in Example 1, and the ratio (%) of the initial capacity / design capacity was measured. The results are shown in Table 2.

  As shown in Table 2, an example including a filler layer using α-alumina having a S content of 10 ppm or more and an X-ray peak intensity ratio I (116) / I (110) of 5 to 200 as a filler. The 22 lithium ion secondary batteries had a battery resistance of 22.5 mΩ and an initial capacity / design capacity ratio of 91%. On the other hand, the lithium ions of Examples 20 and 21 including a filler layer using α-alumina having an S content of less than 10 ppm or an X-ray peak intensity ratio I (116) / I (110) of less than 5 as a filler. Compared with the lithium ion secondary battery of Example 22, the secondary battery had an increased battery resistance (mΩ) and an inferior initial capacity / design capacity ratio. Thus, a lithium ion secondary battery including a filler layer using an alumina having an S content of 10 ppm or more and an X-ray peak intensity ratio I (116) / I (110) of 5 to 200 as a filler is as follows. It can be seen that the battery resistance is low and a high initial capacity can be obtained.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Lithium ion secondary battery 11 Electrode body 12 Positive electrode 13 Separator 14 Negative electrode 15 Battery case 20 Non-aqueous electrolyte 60 Resin layer 61 PP layer 62 PE layer 63 PP layer 70 Filler layer 122 Positive electrode current collector 124 Positive electrode mixture layer 142 Negative Electrode Current Collector 144 Negative Electrode Mixture Layer 152 Case Body 154 Lid

Claims (9)

General formula:
Al ₂ O _3. (H ₂ O) _x
(In the above formula, x satisfies 0 ≦ x ≦ 2)
Adjusting the sulfur (S) content of the filler, which is substantially composed of an inorganic material represented by the formula (1) and containing sodium (Na) and sulfur (S) as trace components, to at least 10 ppm on a mass basis,
A non-aqueous electrolyte secondary battery is prepared by preparing a positive electrode and a negative electrode, disposing a separator between the positive electrode and the negative electrode, and forming a filler layer between the positive electrode and the negative electrode using the adjusted filler. Including,
The sodium (Na) content in the filler is 5 ppm or more on a mass basis,
The content of the trace component in the filler is 1% by mass or less,
When the inorganic material of the filler satisfies 1 ≦ x ≦ 2 in the general formula, the X-ray peak intensity ratio I (020) / I of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα). When (120) is 5 to 200, or when the inorganic material of the filler satisfies 0 ≦ x <1 in the general formula, the wide angle X-ray diffraction spectrum (CuKα) A method for producing a nonaqueous electrolyte secondary battery, wherein the obtained inorganic material has an X-ray peak intensity ratio I (116) / I (110) of 5 to 200.   The manufacturing method according to claim 1, wherein the inorganic material satisfies 1 ≦ x ≦ 2 in the general formula.   The manufacturing method according to claim 1, wherein the inorganic material satisfies 0 ≦ x <1 in the general formula.   The manufacturing method in any one of Claim 1 to 3 which adjusts sulfur (S) content of the said filler to 10 ppm-50 ppm on a mass basis. A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and a filler layer further disposed between the positive electrode and the negative electrode. And
The filler layer has the general formula:
Al ₂ O _3. (H ₂ O) _x
(In the above formula, x satisfies 0 ≦ x ≦ 2)
Comprising a filler containing sodium (Na) and sulfur (S) as minor components, which is substantially composed of an inorganic material represented by:
The sulfur (S) content in the filler is at least 10 ppm on a mass basis;
The sodium (Na) content in the filler is 5 ppm or more on a mass basis,
The content of the trace component in the filler is 1% by mass or less,
When the inorganic material satisfies 1 ≦ x ≦ 2 in the general formula, the X-ray peak intensity ratio I (020) / I (120 of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα). ) Is 5-200,
When the inorganic material satisfies 0 ≦ x <1 in the general formula, the X-ray peak intensity ratio I (116) / I (110) of the inorganic material obtained by a wide-angle X-ray diffraction spectrum (CuKα). ) Is a 5-200 non-aqueous electrolyte secondary battery.   The non-aqueous electrolyte secondary battery according to claim 5, wherein the inorganic material satisfies 1 ≦ x ≦ 2 in the general formula.   The non-aqueous electrolyte secondary battery according to claim 5, wherein the inorganic material satisfies 0 ≦ x <1 in the general formula.   The nonaqueous electrolyte secondary battery according to any one of claims 5 to 7, wherein a sulfur (S) content in the filler is 10 ppm to 50 ppm on a mass basis.   A vehicle comprising the nonaqueous electrolyte secondary battery according to any one of claims 5 to 8.

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