JP2008021635A - Non-aqueous electrolyte secondary battery electrode and non-aqueous electrolyte secondary battery using the same - Google Patents

Abstract

To provide means capable of improving cycle life and high-temperature durability in a non-aqueous electrolyte secondary battery.
An electrode for a nonaqueous electrolyte secondary battery having a current collector and an active material layer containing an active material and a binder disposed on a surface of the current collector, wherein the binder is an epoxy resin. In addition, 50 to 100% by mass of one or more thermosetting resins selected from the group consisting of phenolic resins and polyimides with respect to the total mass of the binder, and the thickness of the active material layer is 30
An electrode for a non-aqueous electrolyte secondary battery, wherein the electrode is from μm to 300 μm.
[Selection figure] None

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to an electrode for a non-aqueous electrolyte secondary battery including a binder made of a specific material and a non-aqueous electrolyte secondary battery using the same.

  There is growing interest in electric and hybrid vehicles to address the problems of global environmental pollution and global warming. As one of these power sources, nonaqueous electrolyte secondary batteries represented by lithium secondary batteries have been widely developed.

  In the nonaqueous electrolyte secondary battery, characteristics such as cycle life, energy density, and power density are important. The cycle life is particularly important when a nonaqueous electrolyte secondary battery is used as a power source for a vehicle. This is because in a vehicle that is normally used for several years or more, if the cycle life is shortened, the reliability of the vehicle is greatly affected. For this reason, it is desired to maximize the cycle life.

When the charge / discharge cycle is repeated, the electrode layer peels off from the current collector and the internal resistance increases, so that the battery capacity decreases. As an attempt to solve this problem, a technique for improving a fluororesin such as vinylidene fluoride, which has been conventionally used as a binder, has been proposed. For example, in an active material layer composed of an electrode active material and a binder, the use of a copolymer of vinylidene fluoride and hexafluoropropylene as a binder prevents peeling of the active material layer from the current collector. A technique for improving the characteristics has been proposed (see Patent Document 1). Further, Patent Document 2 proposes a secondary battery using a cured product of a composition mainly composed of an epoxy resin as a binder.
JP 2000-133270 A JP 2000-133273 A

  However, even if the technique of the above-mentioned document is used, since the cycle life greatly affects the reliability of the battery-mounted device, it is desired to develop further means for improving the cycle life. In particular, when a battery is used / stored at a high temperature, there is a demand for development of a means for improving the cycle life of the battery, that is, a battery excellent in high temperature durability. Then, an object of this invention is to provide the means which can improve a cycle life and high temperature durability in a nonaqueous electrolyte secondary battery.

  The present invention has been made in view of the above problems. The present invention is an electrode for a nonaqueous electrolyte secondary battery having a current collector and an active material layer containing an active material and a binder disposed on the surface of the current collector, wherein the binder is an epoxy resin In addition, 50 to 100% by mass of one or more thermosetting resins selected from the group consisting of phenol resins and polyimides are included with respect to the total mass of the binder, and the thickness of the active material layer is 30 μm or more and 300 μm or less. An electrode for a nonaqueous electrolyte secondary battery is provided.

  According to the non-aqueous electrolyte secondary battery using the electrode of the present invention, since the cycle characteristics are maintained even at high temperatures, the battery life can be extended. Furthermore, a long-life and highly reliable vehicle is provided by applying a non-aqueous electrolyte secondary battery or an assembled battery in which a plurality of non-aqueous electrolyte secondary batteries are connected to a vehicle such as an automobile or a train.

(First embodiment)
1st Embodiment of this invention is an electrode for nonaqueous electrolyte secondary batteries which has an electrical power collector and the active material layer containing the active material and binder which were arrange | positioned on the surface of the said electrical power collector, The binder contains 50 to 100% by mass of one or more thermosetting resins selected from the group consisting of epoxy resins, phenolic resins and polyimides with respect to the total mass of the binder, and the thickness of the active material layer is 30 μm. The electrode for a non-aqueous electrolyte secondary battery is characterized by being 300 μm or less.

  Hereafter, the member which comprises the electrode for nonaqueous electrolyte secondary batteries of this embodiment is demonstrated easily.

[binder]
The 1st characteristic of this invention is that the binder in an active material layer contains 1 or more types of thermosetting resins chosen from the group which consists of an epoxy resin which is a thermosetting resin, a phenol resin, and a polyimide. .

  The epoxy resin is not particularly limited as long as it is thermosetting. Specific examples of the epoxy resin include, for example, bisphenol type epoxy resins such as bisphenol A type and bisphenol F type, phenol novolac type epoxy resins, cresol novolac type epoxy resins, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, and polyethers. Examples thereof include modified epoxy resins and silicone-modified epoxy resins. A bisphenol type epoxy resin is preferred because it can be used stably (electrochemical and electrolytic solution resistance) in the battery. These may be used alone or in combination of two or more.

  The phenol resin is not particularly limited as long as it is thermosetting. Specific examples of the phenolic resin include novolac type phenolic resin, resol type phenolic resin, and epoxy-modified phenolic resin. These may be used alone or in combination of two or more.

  The polyimide is not particularly limited as long as it is thermosetting. Specific examples of the polyimide include condensation type polyimide and addition type polyimide. These may be used alone or in combination of two or more.

  When the total mass of the binder is 100 mass% (hereinafter, mass% is simply referred to as “%”), the total total mass of the thermosetting epoxy resin, phenol resin, and polyimide contained in the binder is 50 to 100. %, More preferably 70 to 100%. Within this range, the active material is difficult to peel from the current collector, and the durability of the battery at high temperatures is improved, which is preferable.

  In addition to the specific thermosetting resin, a conventionally known material used for the binder may be used for the binder. Specifically, thermoplastic resins such as polyvinylidene fluoride (PVdF), polyvinyl acetate, acrylic resin, polyethylene, polystyrene, polypropylene, polysulfone, polycarbonate, polytetrafluoroethylene; urea resin, polyurethane resin, silicon resin, Thermosetting resins such as saturated polyester resins; rubber materials such as butyl rubber, styrene rubber, polyisoprene rubber, olefin rubber, urethane rubber, polyamide rubber, acrylic rubber, and fluororubber.

  In addition, the said binder may be contained in the active material layer of any one of a positive electrode and a negative electrode, or may be contained in both. From the viewpoint of high output, it is preferable that the binder is contained in at least the positive electrode, and more preferably, the binder is contained in both the positive electrode and the negative electrode.

[Active material layer]
The active material layer contains an active material in addition to the above binder, and further contains other additives as necessary.

The positive electrode active material layer includes a positive electrode active material. As the positive electrode active material, for example, Li · Co-based composite oxide such as LiCoO _2, Li · Ni-based composite oxide such as LiNiO _2, Li · Mn-based composite oxide such as spinel LiMn ₂ O _4, LiFeO _2, etc. Lithium-transition metal oxides such as Li · Fe-based composite oxides; lithium-transition metal phosphate compounds such as LiMPO ₄ (M = Fe, Mn, Co, Ni), and lithium-transition metal sulfate compounds. . These may be used alone or in combination of two or more.

As the positive electrode active material, it is preferable to use one or more selected from the group consisting of Ni-based, ternary-based, and olivine-based materials from the viewpoint of improving cycle characteristics at high temperatures. The Ni-based, ternary-based, and olivine-based materials are not particularly limited, but the following are exemplified. Examples of Ni-based materials include LiNiO ₂ , LiNiO ₂ partially substituted with Co or Mn (eg, LiNiCoO ₂ , LiNiMnO _2, etc.), Co and Mn substituted (eg, LiNiMnCoO ₂ ), or Co And those substituted with Al (for example, LiNiCoAlO ₂ or the like), or those substituted with other transition metals (for example, LiNiCoAlMO ₂ or the like). Examples of the ternary system include LiNi _1/3 Mn _1/3 Co _1/3 O ₂ in which the ratio of Ni, Mn, and Co is 1: 1: 1. Examples of the olivine system include LiMPO ₄ (M = Fe, Mn, Co, Ni) represented by LiFePO ₄ .

  The negative electrode active material layer includes a negative electrode active material. Examples of the negative electrode active material include carbon materials such as graphite, soft carbon, and hard carbon, lithium-transition metal compounds, metal materials, and lithium-metal alloy materials as described above. These may be used alone or in combination of two or more.

  The average particle size of each active material contained in each active material layer is not particularly limited, but is preferably 0.01 to 100 μm, more preferably 1 to 50 μm. In the present specification, “particle diameter” means the maximum distance L among the distances between any two points on the particle outline, and the value of “average particle diameter” Using observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM), a value calculated as an average value of particle diameters of particles observed in several to several tens of fields is adopted. .

  Examples of additives other than the binder that can be included in the positive electrode active material layer and the negative electrode active material layer include a conductive additive, an electrolyte salt (lithium salt), and an electrolyte.

  The conductive assistant refers to an additive that is blended in order to improve the conductivity of the positive electrode active material layer or the negative electrode active material layer. Examples of the conductive assistant include carbon materials such as carbon black such as acetylene black, graphite, and vapor grown carbon fiber. When the active material layer contains a conductive additive, an electronic network inside the active material layer is effectively formed, which can contribute to improvement of the output characteristics of the battery.

Examples of the electrolyte salt (lithium salt) include Li (C ₂ F ₅ SO ₂ ) ₂ N, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO _{3 and the} like. The electrolyte is described in detail in the section “Electrolyte” below.

  The compounding ratio of the components contained in the positive electrode active material layer and the negative electrode active material layer is not particularly limited. The blending ratio can be adjusted by appropriately referring to known knowledge about the nonaqueous electrolyte secondary battery.

  In the present embodiment, the thickness of each active material layer is not less than 30 μm and not more than 300 μm. When the capacity per unit cell is increased, the active material layer is preferably thicker. However, when the active material layer is thicker, there is a possibility that the adhesion between the materials of the active material layer may be reduced when a conventional binder is used. In some cases, the blending amount of the binder had to be increased. In contrast, by using the binder of the present embodiment, even when the thickness of the active material layer is as thick as 30 μm or more, the adhesion between the materials of the active material layer without increasing the blending amount of the binder. Can be secured. The thickness of the active material layer suppresses a decrease in energy density, and is preferably 50 μm or more and 200 μm or less.

  The blending amount of the binder in the active material layer is not particularly limited, but is preferably 5 to 50%, and more preferably 5 to 20%. If it exists in this range, since the fall of an energy density can be prevented, it is preferable.

[Current collector (including outermost layer current collector)]
The current collector and the outermost layer current collector are made of a conductive material such as an aluminum foil, a copper foil, or a stainless steel (SUS) foil. The general thickness of the current collector is 1 to 30 μm.

  The size of the current collector is determined according to the intended use of the nonaqueous electrolyte secondary battery. If a large electrode used for a large battery is manufactured, a current collector having a large area is used. If a small electrode is produced, a current collector with a small area is used.

[Production method]
The electrode of the present embodiment can be manufactured by a conventionally known method for manufacturing an electrode for a nonaqueous electrolyte secondary battery. For example, it can be manufactured by preparing an active material slurry by adding an active material and a thermosetting resin to an organic solvent, and applying the active material slurry to the surface of a current collector to form a coating film. Specifically, a desired active material and a thermosetting resin, and other components (for example, a conductive assistant, a supporting salt (lithium salt), an ion conductive polymer, etc.) are mixed in a solvent as necessary. To prepare an active material slurry. The kind of solvent and the mixing means are not particularly limited, and conventionally known knowledge about electrode production can be appropriately referred to. As an example of the solvent, N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methylformamide and the like can be used. Subsequently, the active material slurry prepared above is applied to the surface of the current collector prepared above to form a coating film. Thereafter, drying and pressing are performed. Also, the application means for applying the active material slurry is not particularly limited. For example, a commonly used means such as a coater can be adopted.

(Second Embodiment)
The second embodiment is a nonaqueous electrolyte secondary battery using the electrode of the first embodiment. Such a non-aqueous electrolyte secondary battery has good high-temperature durability and is expected to extend the life of the battery. The electrode of the first embodiment may be used for at least one of the positive electrode and the negative electrode. However, since the effect of the present invention is remarkably obtained, it is preferably used at least for the positive electrode. It is more preferable to use both.

  In the nonaqueous secondary battery of the present invention, in addition to the electrode elements of the first embodiment, generally known electrode components are used. Hereinafter, members constituting the battery of this embodiment will be described.

[Separator]
The separator used in the present invention is not particularly limited, and may be a nonwoven fabric separator or a microporous membrane separator.

  As the nonwoven fabric separator, for example, a sheet in which fibers are entangled can be used. In addition, a spunbond obtained by fusing fibers together by heating can also be used. In other words, it may be in the form of a sheet formed by arranging fibers in a web (thin cotton) shape or mat shape by an appropriate method, and joining them using an appropriate adhesive or the fusing force of the fibers themselves. The fiber to be used is not particularly limited, and examples thereof include polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate (PET), cellulose, rayon, acetate, nylon (registered trademark), polyimide, aramid, ceramics, and the like. A conventionally well-known thing can be used.

  As the microporous membrane separator, for example, a porous sheet (for example, a polyolefin microporous membrane separator) made of a polymer that absorbs and holds an electrolyte can be used. The polyolefin microporous membrane separator having the property of being chemically stable with respect to an organic solvent has an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low. Examples of the material of the polyolefin microporous membrane separator include a laminate having a three-layer structure of polyethylene (PE), polypropylene (PP), and PP / PE / PP. In addition, examples of the material of the microporous membrane separator include polyimide, aramid, polyethylene terephthalate, and the like.

  The material constituting the separator used in the present embodiment preferably includes one or more materials selected from the group consisting of polypropylene, polyimide, polyethylene terephthalate (PET), aramid, cellulose, and ceramics. It is preferable to use such a material because the high temperature durability of the battery is further improved. In order to improve the high temperature durability of the battery, the preferable material is contained in 100% of the material constituting the separator, preferably 80% or more, more preferably 90% or more, and further preferably 100%. Moreover, although the said preferable material may be used individually by 1 type or may be used together 2 or more types, it is preferable to use individually by 1 type from the point of productivity.

  The separator described above is sandwiched between the electrodes, and can be used as an electrolyte by impregnating the electrolyte when an electrolyte is used as the electrolyte described later. Therefore, when the above electrodes are used and a separator impregnated with an electrolyte solution is sandwiched between the electrodes as an electrolyte, these combinations form one set of battery elements. If necessary, this one set may be wrapped with an exterior material and used as it is as a non-aqueous electrolyte secondary battery, or a plurality of sets may be laminated and wrapped with an exterior material to be used as a non-aqueous electrolyte secondary battery. good.

  In addition, when the said preferable material is used, high temperature durability improves further by the combination with the specific binder used in an active material layer. Specifically, (1) the material constituting the separator includes polyimide and the binder includes thermosetting polyimide; (2) the material constituting the separator includes at least one kind of PET or aramid, and the binder includes a phenol resin. Or a form containing at least one epoxy resin; (3) a form in which polypropylene is contained in the material constituting the separator and at least one phenol resin or epoxy resin is contained in the binder. The form of (1) to (3) may be a combination of at least one of a positive electrode and a negative electrode binder and a separator, but since the effects of the present invention are remarkably obtained, both the positive electrode and negative electrode binders are used. More preferred is a combination of a separator and a separator.

[Insulating fine particle mixed material]
In the present embodiment, an insulating fine particle mixed material containing a thermosetting adhesive and insulating fine particles is disposed between the active material layer and the separator between the active material layer and the separator. It is preferable. By disposing the insulating fine particle mixed material, the heat resistance is further improved and the high temperature durability is further improved. Further, by using a thermosetting binder, the adhesion of the insulating fine particles is good even at high temperatures.

  “Insulating fine particles” mean particles having electrical insulating properties. The material constituting the insulating fine particles is not particularly limited as long as it is a material exhibiting electrical insulation, and a conventionally known material can be appropriately used. Specifically, a ceramic material or an organic polymer material can be used as a material constituting the insulating fine particles. By forming the insulating fine particles using these materials, the function of preventing the short circuit between the positive and negative electrodes required for the separator can be sufficiently exhibited.

Examples of these insulating fine particles include oxides such as lithium ferrite (LiFeO ₂ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconia, magnesia, titania, silica alumina, chromium oxide, and ruthenium oxide. , Nitrides such as aluminum nitride and silicon nitride, acrylic materials such as LiFePO ₄ , polymethyl acrylate and polymethyl methacrylate, polyimide materials such as fluorinated imide, polystyrene, polypropylene, polysulfone, phenolic resin, unsaturated A polyester resin etc. are mentioned. Among these materials, LiFeO ₂ , SiO ₂ , and Al ₂ O ₃ are preferably used in terms of electronic conductivity (insulating properties) and mechanical strength (having a higher short-circuit prevention function). Only 1 type of these materials may be used independently, and 2 or more types may be used together.

  The insulating fine particles may be all particles made of a ceramic material (ceramic particles), all particles made of an organic polymer material (organic polymer particles), or a mixture of these particles. It may be. When the form of the mixture is adopted, the mixing ratio of the ceramic particles and the organic polymer particles is not particularly limited, but is preferably a ratio of ceramic particles: organic polymer particles (volume ratio), preferably 10-20: 1-10. More preferably, it is 10-15: 3-10.

  In the present embodiment, the average particle size of the insulating fine particles is preferably 10 nm to 30 μm, more preferably 50 nm to 25 μm, still more preferably 100 nm to 20 μm, and most preferably 1000 nm to 10 μm. If the insulating fine particles are within this range, the volume energy density of the battery is appropriate, and even if the insulating fine particles fall off due to vibration during use of the battery, the insulating properties of such a relatively small size. By using the fine particles, occurrence of a short circuit between the positive and negative electrodes (short circuit) can be sufficiently suppressed.

  In the present embodiment, the insulating fine particles are bound together by the thermosetting adhesive contained in the insulating fine particle mixed material, and the adhesion between the separator and the active material layer can also be improved. . As a result, reliability such as vibration resistance of the nonaqueous electrolyte secondary battery can be improved. Examples of the thermosetting adhesive include urea resin, epoxy resin, polyurethane resin, silicon resin, phenol resin, and unsaturated polyester resin.

  The blending amount of the thermosetting adhesive in the insulating fine particle mixed material is not particularly limited, but is preferably 1 to 80%, more preferably 3 to 100% when the total amount of the insulating fine particle mixed material is 100%. 50%. When the added amount of the adhesive is within such a range, a battery having an excellent balance of binding property, adhesion, and volume energy density can be provided.

  Examples of the arrangement method of the insulating fine particle mixed material include a method of applying to the surface of the active material layer. When applying the insulating fine particle mixed material to the surface of the active material layer, it is preferable to apply 70% or more with respect to 100% of the active material layer area. Specific examples of the application method include a method in which a slurry containing insulating particles (insulating particle slurry) is separately prepared and applied to at least one surface (preferably both surfaces) of the active material layer.

  The solvent used in preparing the insulating particle slurry is not particularly limited, and specific examples include polar solvents such as N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, and methylformamide.

  The concentration of the insulating particles and the binder in the insulating particle slurry and the viscosity of the slurry are not particularly limited, and may be appropriately determined in consideration of the application method to the active material layer. Specifically, the viscosity of the insulating particle slurry is preferably 0.5 to 8.0 Pa · s, more preferably 1.0 to 4.0 Pa · s.

  The application means for applying the insulating particle slurry to the surface of the active material layer is not particularly limited, and a conventionally known technique can be appropriately employed in the battery manufacturing field. For example, methods such as a doctor blade method, an ink jet method, a screen printing method, and a die coater method are exemplified.

  Further, the insulating particle slurry applied to the surface of the active material layer may be dried and heated. The heating may be performed after the application of the insulating particle slurry and before the lamination of the electrodes, or may be performed after the lamination. In a preferred embodiment, heating is performed after the electrodes are stacked. According to such a form, in addition to the improvement of the binding property between the insulating particles, the effect of improving the adhesion of the active material layer, the separator, and the insulating particle mixed material is also obtained.

[Electrolytes]
As the electrolyte, conventionally known electrolytes can be used, and examples thereof include liquid electrolytes (electrolytic solutions), solid electrolytes, polymer electrolytes (intrinsic polymer electrolytes, gel polymer electrolytes, and the like). Examples of the electrolyte salt used in the electrolytic solution include lithium salts such as LiBETI, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ . Examples of the solvent include carbonates such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). When these electrolytic solutions are used as electrolytes for non-aqueous secondary batteries, they are used in the separator.

  The polymer electrolyte is composed of an ion conductive polymer, and the material is not limited as long as it exhibits ion conductivity. In view of the fact that excellent mechanical strength can be expressed, a polymerized ion conductive polymer that is crosslinked by thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, or the like is preferably used.

  Examples of the polymer electrolyte include an intrinsic polymer electrolyte and a gel polymer electrolyte. The intrinsic polymer electrolyte is not particularly limited, and examples thereof include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

  The gel polymer electrolyte generally refers to an electrolyte solution held in an all-solid polymer electrolyte having ion conductivity. In the present application, a gel polymer electrolyte also includes a polymer skeleton having no ion conductivity and a similar electrolyte solution held therein. When these polymer electrolytes are used as electrolytes for non-aqueous secondary batteries, they are used by being sandwiched between electrodes in the state described here.

[Electrode terminal]
The material of the electrode terminal is not particularly limited, and a known material conventionally used as an electrode terminal for a secondary battery can be used. Examples thereof include aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof.

[Exterior material]
The exterior material is not particularly limited, and a conventionally known exterior material can be used. Easily cool the heat from the heat source of the car or the self-heating of the battery due to high load, and efficiently transfer the heat from the car's heat source at the time of cold start, and can quickly heat the inside of the battery to the battery operating temperature In this respect, preferably, a polymer-metal composite laminate sheet having excellent thermal conductivity can be used. Further, by placing the inside of the laminate at a pressure lower than the atmospheric pressure, it becomes possible to make contact between the battery elements or between the battery elements and the electrode terminals at atmospheric pressure, and further to reduce the contact resistance. .

  The nonaqueous electrolyte secondary battery of the present embodiment can be manufactured by appropriately referring to conventionally known knowledge without using a special technique.

  The non-aqueous electrolyte secondary battery of the present invention is not particularly limited as long as it uses a non-aqueous electrolyte, but is preferably a lithium ion secondary battery from the viewpoint of practicality.

  The nonaqueous electrolyte secondary battery of the present invention is not particularly limited in terms of structure and connection form, and conventionally known forms can be used. For example, examples of the battery structure include a stacked (flat) battery, a wound (cylindrical) battery, and the like. Examples of the electrical connection form (electrode structure) in the battery include internal series connection (bipolar type) and internal parallel connection.

(Third embodiment)
In the third embodiment, a plurality of the nonaqueous electrolyte secondary batteries of the second embodiment are connected in parallel and / or in series to constitute an assembled battery.

  The connection method in particular when connecting the some nonaqueous electrolyte secondary battery which comprises an assembled battery is not restrict | limited, A conventionally well-known method can be employ | adopted suitably. For example, a technique using welding such as ultrasonic welding or spot welding, or a technique of fixing using rivets, caulking, or the like can be employed. According to such a connection method, the long-term reliability of the assembled battery can be improved.

  According to the assembled battery of the present embodiment, the nonaqueous electrolyte secondary battery of the second embodiment is used to form an assembled battery, so that sufficient capacity characteristics are ensured and sufficient even under high output conditions. An assembled battery capable of exhibiting output can be provided.

  In addition, the connection of the nonaqueous electrolyte secondary batteries constituting the assembled battery may be all connected in parallel, or all may be connected in series. You may combine.

(Fourth embodiment)
In the fourth embodiment, a vehicle is configured by mounting the nonaqueous electrolyte secondary battery of the second embodiment or the assembled battery of the third embodiment as a motor driving power source. As a vehicle using a nonaqueous electrolyte secondary battery or a battery pack as a power source for a motor, for example, a wheel such as a complete electric vehicle not using gasoline, a hybrid vehicle such as a series hybrid vehicle or a parallel hybrid vehicle, and a fuel cell vehicle is used. An automobile driven by a motor can be mentioned. The nonaqueous electrolyte secondary battery according to the second embodiment or the assembled battery according to the third embodiment is excellent in high-temperature durability, so that it is possible to place the battery even in the vicinity of components that are likely to become high temperature. Also from the viewpoint of vehicle mounting properties, it is preferable to use the nonaqueous electrolyte secondary battery or the assembled battery of the present invention for the vehicle.

  As described above, some preferred embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications, omissions, and additions can be made by those skilled in the art. .

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Unless otherwise specified, mass% is simply “%”.

<Example 1>
A slurry was prepared as follows so that the ratio of the thermosetting resin (bisphenol A type epoxy resin) to 100% of the total binder mass in the electrode was 50%.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (positive electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 20% acetylene black, 5% PVdF as a binder and 5% one-component epoxy resin (Bisphenol A type epoxy resin) was mixed, 41% of NMP (N-methyl-2-pyrrolidone) was added as a solvent to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (negative electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 7.5% PVdF as binder and 7.5% one-part epoxy resin (bisphenol) A type epoxy resin) was mixed, 41% of NMP was added as a solvent to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry.

(3) Application (electrode preparation)
Positive and negative electrodes: An aluminum foil having a thickness of about 10 μm was used as a current collector, and positive electrode ink was applied to both surfaces of the aluminum foil as a positive electrode. A copper foil having a thickness of about 10 μm was used as a current collector, and a negative electrode was prepared by applying negative electrode ink on both sides of the copper foil. Then, it dried at 120 degreeC and pressed. Pressing was performed so that the thickness of the active material layer after pressing was 60 μm for the positive electrode and 65 μm for the negative electrode.

(4) Terminal Lead An Al plate having a thickness of 150 μm, a width of 40 mm, and a length of 50 mm was used for the positive electrode terminal lead, and a Ni plate was applied to a Cu plate having a thickness of 150 μm, a width of 40 mm, and a length of 50 mm for the negative electrode terminal lead. A terminal lead was used.

(5) Assembling The positive electrode and the negative electrode are laminated via a microporous membrane separator made of polypropylene, and a laminate of 11 positive electrodes and 11 negative electrodes is laminated to a laminate film (outermost layer for surface protection). PET film, a metal film layer made of Al foil, and a heat-fusing insulating film layer made of polypropylene, and a positive electrode current collector and a negative electrode current collector are projected from opposite sides of the separator. The electrode terminal made of Al and the terminal lead made of Ni are welded, sandwiched between the laminate films of the exterior, the positive electrode terminal and the negative electrode terminal are respectively protruded from the opposite sides of the battery, the peripheral part is heated and welded, and the electrolyte is injected. Then, a laminated exterior flat battery having a width of 100 mm, a length of 150 mm, and a thickness of about 3 mm was produced.

<Example 2>
A slurry was prepared as follows so that the ratio of the thermosetting resin (bisphenol A type epoxy resin) to the total binder mass in the electrode was 70%.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% acetylene black, 3% PVdF as a binder and 7% one-part epoxy resin (bisphenol A type epoxy resin) were mixed. A slurry was prepared by adding 41% of NMP as a solvent to 100% of the mixture and stirring sufficiently.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. A mixture of 85% amorphous carbon having an average particle size of 10 μm, 4.5% PVdF as a binder and 10.5% one-component epoxy resin (bisphenol A type epoxy resin), and the mixture To 100%, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(3) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. The separator used was a polypropylene microporous membrane separator as in Example 1.

<Example 3>
A slurry was prepared as follows so that the ratio of the thermosetting resin (bisphenol A type epoxy resin) to the total binder mass in the electrode was 100%.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% acetylene black, and 10% one-component epoxy resin (bisphenol A type epoxy resin) as a binder are mixed, and the mixture is 100%. On the other hand, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (average particle size 10 μm) and 15% one-component epoxy resin (bisphenol A type epoxy resin) as a binder are mixed, and 100% of the mixture is used as a solvent. A slurry was prepared by adding 41% NMP and stirring well.

(3) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. The separator used was a polypropylene microporous membrane separator as in Example 1.

<Example 4>
A slurry was prepared as follows so that the ratio of the thermosetting resin (polyimide or bisphenol A type epoxy resin) to the total binder mass in the electrode was 70%.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% acetylene black, 3% PVdF as a binder and 7% polyimide resin were mixed, and 100% of the mixture was mixed with a solvent. As a slurry, 41% NMP was added and sufficiently stirred.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (average particle size 10 μm), 4.5% PVdF as binder and 10.5% one-component epoxy resin (bisphenol A type epoxy resin) are mixed, To 100% of the mixture, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(3) Production of Battery A laminated exterior flat battery was produced in the same manner as in Examples 1 (3) to (5). However, a polyimide microporous membrane separator was used as the separator.

<Example 5>
(1) Preparation of ink In the same manner as in Example 4 (1) and (2), positive and negative electrode inks were prepared.

(2) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. However, a PET microporous membrane separator was used as the separator.

<Example 6>
(1) Preparation of ink In the same manner as in Example 4 (1) and (2), positive and negative electrode inks were prepared.

(2) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. However, the separator used was a microporous membrane separator made of aramid resin.

<Example 7>
A slurry was prepared as follows so that the ratio of the thermosetting resin (phenol resin) to the total binder amount in the electrode was 70%.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% acetylene black, 3% PVdF as a binder and 7% phenol resin were mixed, and 100% of the mixture was mixed with a solvent. As a slurry, 41% NMP was added and sufficiently stirred.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (average particle size 10 μm), 4.5% PVdF as binder and 10.5% phenol resin are mixed, and NMP is used as a solvent with respect to 100% of the mixture. 41% was added and stirred well to prepare a slurry.

(3) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. However, a PET microporous membrane separator was used as the separator.

<Example 8>
(1) Ink Preparation Positive and negative inks were prepared in the same manner as in Example 7 (1) and (2).

(2) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1. However, the separator used was a microporous membrane separator made of aramid resin.

<Example 9>
A battery in which an insulating fine particle mixed material containing a thermosetting adhesive and insulating fine particles was disposed between the active material layer and the separator was produced as follows.

(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% acetylene black, 3% PVdF as a binder and 7% one-part epoxy resin (bisphenol A type epoxy resin) were mixed. A slurry was prepared by adding 41% of NMP as a solvent to 100% of the mixture and stirring sufficiently.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (average particle size 10 μm), 4.5% PVdF as binder and 10.5% one-component epoxy resin (bisphenol A type epoxy resin) are mixed, To 100% of the mixture, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(3) Application (electrode preparation)
As the positive electrode, an aluminum foil having a thickness of about 10 μm was used as a current collector, and the positive electrode was coated with positive ink on both sides of the aluminum foil. As the negative electrode, a copper foil having a thickness of about 10 μm was used as a current collector, and a negative electrode was prepared by applying negative electrode ink on both sides of the copper foil. A mixture of 70% alumina particles having a particle size of 1 μm as ceramic fine particles, 10% of a one-part epoxy resin (bisphenol A type epoxy resin) as a thermosetting adhesive, and NMP as a solvent is added to the positive electrode active material. In addition, it was applied with a die coater method and a thickness of 5 μm. Then, it dried at 120 degreeC and pressed. Pressing was performed so that the thickness of the active material layer after pressing was 60 μm for the positive electrode and 65 μm for the negative electrode.

(4) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (4) to (5) of Example 1.
<Example 10>
(1) Preparation of ink In the same manner as in (1) and (2) of Example 1, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 30 μm for the positive electrode and 33 μm for the negative electrode.

(3) Production of Battery A laminated exterior flat battery was produced in the same manner as in (4) to (5) of Example 1.
<Example 11>
(1) Preparation of ink In the same manner as in (1) and (2) of Example 1, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 100 μm for the positive electrode and 110 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 12>
(1) Preparation of ink In the same manner as in (1) and (2) of Example 1, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 150 μm for the positive electrode and 165 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 13>
(1) Ink Preparation In the same manner as in Example 1 (1) and (2), positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 200 μm for the positive electrode and 220 μm for the negative electrode.

(3) Production of Battery The battery was produced in the same manner as (4) to (5) in Example 1.

<Example 14>
(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (positive electrode active material capable of inserting and extracting Li ions, average particle size 10 μm), 15% acetylene black, 7.5% PVdF and 7.5% of binder Liquid epoxy resin (bisphenol A type epoxy resin) was mixed, and 41% of NMP (N-methyl-2-pyrrolidone) was added as a solvent to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry. .

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 80% amorphous carbon (negative electrode active material capable of inserting and extracting Li ions, average particle size 10 μm), 10% PVdF as binder and 10% one-part epoxy resin (bisphenol A type epoxy resin) And 41% of NMP as a solvent was added to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry.

(3) Application (electrode preparation)
An aluminum foil having a thickness of about 10 μm was used as a current collector, and a positive electrode was formed by applying positive electrode ink on both sides of the aluminum foil. A copper foil having a thickness of about 10 μm was used as a current collector, and a negative electrode was prepared by applying negative electrode ink on both sides of the copper foil. Then, it dried at 120 degreeC and pressed. Pressing was performed so that the thickness after pressing was 300 μm for the positive electrode and 280 μm for the negative electrode.

(4) Production of Battery The battery was produced in the same manner as (4) to (5) in Example 1.

<Example 15>
(1) Preparation of ink In the same manner as in (2) of Example 2, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 30 μm for the positive electrode and 33 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 16>
(1) Preparation of ink In the same manner as in (2) of Example 2, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 100 μm for the positive electrode and 110 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 17>
(1) Preparation of ink In the same manner as in (2) of Example 2, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 150 μm for the positive electrode and 165 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 18>
(1) Preparation of ink In the same manner as in (2) of Example 2, positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 200 μm for the positive electrode and 220 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 19>
(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (positive electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 15% acetylene black, 4.5% PVdF as a binder and 10.5% Liquid epoxy resin (bisphenol A type epoxy resin) was mixed, and 41% of NMP (N-methyl-2-pyrrolidone) was added as a solvent to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry. .
(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 80% amorphous carbon (negative electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 6% PVdF as binder and 14% one-part epoxy resin (bisphenol A type epoxy resin) And 41% of NMP as a solvent was added to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry.

(3) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 300 μm for the positive electrode and 280 μm for the negative electrode.

(4) Preparation of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 20>
(1) Preparation of positive electrode ink In the same manner as in Example 3 (1), a positive electrode ink was prepared.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. A mixture of 85% amorphous carbon having an average particle size of 10 μm, 4.5% PVdF as a binder and 10.5% one-component epoxy resin (bisphenol A type epoxy resin), and the mixture To 100%, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(3) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 30 μm for the positive electrode and 33 μm for the negative electrode.

(4) Preparation of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 21>
(1) Preparation of ink In the same manner as in Examples 20 (1) and (2), positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 100 μm for the positive electrode and 110 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 22>
(1) Preparation of ink In the same manner as in Examples 20 (1) and (2), positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 1 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 150 μm for the positive electrode and 165 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 23>
(1) Preparation of ink In the same manner as in Examples 20 (1) and (2), positive and negative inks were prepared.

(2) Application (electrode preparation)
The same operation as in Example 20 was performed except that the pressing was performed so that the thickness of the active material layer after pressing was 200 μm for the positive electrode and 220 μm for the negative electrode.

(3) Manufacture of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Example 24>
(1) Ink preparation The positive electrode ink was prepared as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 15% acetylene black, and 15% one-component epoxy resin (bisphenol A type epoxy resin) as a binder are mixed, and the mixture is 100%. On the other hand, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 80% amorphous carbon (negative electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 6% PVdF as binder and 14% one-part epoxy resin (bisphenol A type epoxy resin) And 41% of NMP as a solvent was added to 100% of the mixture, and the mixture was sufficiently stirred to prepare a slurry.

(3) Application Positive and negative electrodes: An aluminum foil of about 10 μm was used as a current collector, and positive electrode ink was applied to both sides of the aluminum foil as a positive electrode. A copper foil having a thickness of about 10 μm was used as a current collector, and a negative electrode was prepared by applying negative electrode ink on both sides of the copper foil. Then, it dried at 120 degreeC and pressed. Pressing was performed so that the thickness of the active material layer after pressing was 270 μm for the positive electrode and 300 μm for the negative electrode.

(4) Preparation of battery It manufactured similarly to (4)-(5) of Example 1. FIG.

<Comparative Example 1>
(1) Preparation of positive electrode ink Preparation of positive electrode ink was performed as follows. 70% LiMn ₂ O ₄ (average particle size 10 μm), 20% by mass of acetylene black, and 10% PVdF as a binder were mixed, and 41% of NMP was used as a solvent with respect to 100% of the mixture. In addition, the slurry was prepared by sufficiently stirring.

(2) Preparation of negative electrode ink The negative electrode ink was prepared as follows. 85% amorphous carbon (average particle size 10 μm) and 15% PVdF as a binder are mixed, and 41% NMP is added as a solvent to 100% of the mixture, and the mixture is sufficiently stirred. A slurry was prepared.

(3) Production of Battery A laminated exterior flat type battery was produced in the same manner as in (3) to (5) of Example 1.

  Table 1 below summarizes the ratio, type, thickness of the active material layer, and separator material of the thermosetting resin in the binder of the examples.

<Durability evaluation>
In each of the examples and comparative examples, the first charge (CCCV) of 0.2 C and the initial discharge of 0.5 C were performed, and then 100 cycles of charge and discharge were performed at 60 ° C. and 1 C. Thereafter, the internal resistance after 100 cycles was measured by IV measurement. Tables 2 and 3 show the results when the internal resistance increase after 100 cycles of the comparative example is taken as 100%.

<Peel strength evaluation>
The electrode produced in the comparative example and the example was cut into a test piece having a width of 10 mm and a length of 50 mm, a tape was attached to the electrode (active material), and the T peel strength was obtained at room temperature (25 ° C.) and a tensile speed of 200 mm / min. It was measured. Tables 4 and 5 show the results of the examples when the strength of the comparative example is 1.

  From the results of Tables 1 to 5, it was shown that the batteries of Examples 1 to 24 were excellent in high temperature durability and had little peeling of the electrode layer.

Claims (11)

A current collector,
An active material layer including an active material and a binder disposed on the surface of the current collector;
A non-aqueous electrolyte secondary battery electrode comprising:
The binder contains 50 to 100% by mass of one or more thermosetting resins selected from the group consisting of epoxy resins, phenolic resins and polyimides with respect to the total mass of the binder, and the thickness of the active material layer is An electrode for a non-aqueous electrolyte secondary battery, wherein the electrode is 30 μm or more and 300 μm or less.   The electrode for a nonaqueous electrolyte secondary battery according to claim 1, wherein the active material layer has a thickness of 50 μm or more and 200 μm or less.   A nonaqueous electrolyte secondary battery comprising the electrode according to claim 1. A non-aqueous electrolyte secondary battery comprising a separator sandwiched between the electrodes,
The non-aqueous electrolyte secondary battery according to claim 3, wherein the material constituting the separator includes one or more selected from the group consisting of polypropylene, polyimide, polyethylene terephthalate, aramid, cellulose, and ceramics.   The non-aqueous electrolyte secondary battery according to claim 4, wherein the binder includes a thermosetting polyimide resin, and the material constituting the separator includes polyimide.   The said binder contains at least 1 sort (s) of a thermosetting phenol resin or a thermosetting epoxy resin, and the material which comprises the said separator contains at least 1 sort (s) chosen from a polypropylene, a polyethylene terephthalate, and an aramid. The non-aqueous electrolyte secondary battery described in 1.   The non-conductive material according to any one of claims 4 to 6, wherein an insulating fine particle mixed material including a thermosetting adhesive and insulating fine particles is disposed between the active material layer and the separator. Water electrolyte secondary battery. The non-aqueous electrolyte secondary battery according to claim 7, wherein the material constituting the insulating fine particles is Al ₂ O ₃ , SiO ₂ or LiFeO ₂ .   The nonaqueous electrolyte secondary battery according to claim 3, wherein the positive electrode active material is at least one selected from the group consisting of Ni-based, ternary-based, and olivine-based materials.   The assembled battery using the nonaqueous electrolyte secondary battery of any one of Claims 3-9.   A vehicle on which the nonaqueous electrolyte secondary battery according to any one of claims 3 to 9 or the assembled battery according to claim 10 is mounted as a motor driving power source.