WO2007145174A1

WO2007145174A1 - Electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery using the same

Info

Publication number: WO2007145174A1
Application number: PCT/JP2007/061744
Authority: WO
Inventors: Osamu Shimamura; Hideaki Horie
Original assignee: Nissan Motor Co., Ltd.
Priority date: 2006-06-14
Filing date: 2007-06-11
Publication date: 2007-12-21
Also published as: JP2008021635A

Abstract

[PROBLEMS] To provide a means for improving the cycle life and the durability at higher temperatures in a non-aqueous electrolyte secondary battery. [MEANS FOR SOLVING PROBLEMS] An electrode for use in a non-aqueous electrolyte secondary battery, which comprises a current collector and an active material layer provided on the surface of the current collector and comprising an active material and a binder, wherein the binder contains at least one thermocurable resin selected from the group consisting of an epoxy resin, a phenol resin and polyimide in an amount of 50 to 100% by mass relative to the total mass of the binder, and wherein the active material layer has a thickness of 30 to 300 μm inclusive.

Description

Specification

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

TECHNICAL FIELD [0001] The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery electrode including a binder composed of a specific material and a non-aqueous electrolyte secondary battery using the same. .

Background art

[0002] In order to cope with the problems of global environmental pollution and global warming, interest in electric cars and hybrid cars is increasing. As one of these power sources, non-aqueous electrolyte secondary batteries represented by lithium secondary batteries have been widely developed!

[0003] In non-aqueous electrolyte secondary batteries, characteristics such as cycle life, energy density, and power density are important. Cycle life is particularly important when non-aqueous electrolyte secondary batteries are used as power sources for vehicles. 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.

[0004] When the charge / discharge cycle is repeated, the electrode layer peels off from the current collector and the internal resistance increases, so the battery capacity decreases. As an attempt to solve this problem, a technique for improving fluorine resin 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, by using a copolymer of vinylidene fluoride and hexafluoropropylene as a noda, A technique for preventing the active material layer from peeling off and improving the cycle characteristics has been proposed! (See JP 2000-133270 A). Furthermore, in the publication of Japanese Patent Laid-Open No. 2000-133273, a secondary battery using a cured product of a composition mainly composed of epoxy resin as a binder is proposed.

Disclosure of the invention

Problems to be solved by the invention

[0005] However, even if the technique of the above-mentioned document is used, the battery is mounted with a cycle life. Development of additional means to improve cycle life is desired because it greatly affects the reliability of the device. In particular, there is a need to develop a battery that improves the cycle life of the battery when it is used and stored at a high temperature, that is, a battery with excellent high-temperature durability. Therefore, an object of the present invention is to provide a means capable of improving cycle life and high-temperature durability in a nonaqueous electrolyte secondary battery.

Means for solving the problem

The present invention has been made in view of the above problems. The present invention is an electrode for a non-aqueous electrolyte secondary battery comprising 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 comprises an epoxy The group power consisting of rosin, phenolic terephthalate and polyimide contains at least one thermosetting selenium selected from 50 to LOO% by mass with respect to the total mass of the binder, and the thickness of the active material layer is Provided is an electrode for a non-aqueous electrolyte secondary battery that is 30 / zm or more and 300 μm or less.

The invention's effect

[0007] According to the nonaqueous electrolyte secondary battery using the electrode of the present invention, the cycle characteristics can be maintained even at high temperatures, so that 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 these are connected to a vehicle such as an automobile or a train.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] (First embodiment)

A first embodiment of the present invention is an electrode for a nonaqueous electrolyte secondary battery comprising a current collector and an active material layer containing an active material and a binder disposed on the surface of the current collector. The binder contains at least one thermosetting resin selected from the group consisting of epoxy resin, phenol resin and polyimide, and contains 50 to LOO mass% with respect to the total mass of the binder, and the active material This is a nonaqueous electrolyte secondary battery electrode having a layer thickness of 30 m or more and 300 m or less.

Hereinafter, members constituting the electrode for the nonaqueous electrolyte secondary battery of the present embodiment will be briefly described.

[0010] [Binder] The first feature of the present invention is that the binder in the active material layer is at least one thermosetting resin that is selected from the group consisting of epoxy resin, phenol resin, and polyimide, which are thermosetting resins. Is to include.

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

[0012] The phenolic resin is not particularly limited as long as it is thermosetting. Specific examples of the phenolic resin include novolak type phenolic resin, resol type phenolic resin, and epoxy modified phenolic resin. These can be used alone or in combination of two or more.

[0013] 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.

[0014] When the total mass of the binder is 100% by mass (hereinafter, mass% is simply referred to as “%”), the thermosetting epoxy resin, phenol resin, and polyimide contained in the binder are used. The total total mass is preferably 50 to 100%, more preferably 70 to 100%. Within this range, the active material is less likely to peel from the current collector, and the durability of the battery at high temperatures is improved, which is preferable.

[0015] In addition to the specific thermosetting resin, a conventionally known material used for a binder may be used for the noinder. Specific examples include polyvinylidene fluoride (PVdF), polyacetate butyl, acrylic resin, polyethylene, polystyrene, polypropylene, polysulfone, polycarbonate, polytetrafluoroethylene, and the like; urea resin Thermosetting resin such as Polyurethane resin, Key resin resin, Unsaturated polyester resin; Rubber materials such as rubber, styrene rubber, polyisoprene rubber, polyolefin rubber, urethane rubber, polyamide rubber, attalinole rubber and fluororubber.

[0016] The binder may be contained in one of the active material layer of the positive electrode or the 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.

[0017] [Active material layer]

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

[0018] The positive electrode active material layer includes a positive electrode active material. Examples of the positive electrode active material include LiCoO.

2

Li'Co complex oxide, Li'Ni complex oxide such as LiNiO, Spinel LiMn O etc. Li '

2 2 4

Lithium transition metal oxides such as Mn complex oxides and Li'Fe complex oxides such as LiFeO

2

Lithium transition metal phosphate compounds such as LiMPO (M 2 Fe, Mn, Co, Ni), Lithium

Four

Examples include mu transition metal sulfate compounds. These can be used alone or in combination of two or more!

[0019] As the positive electrode active material, it is preferable to use at least one selected from Ni, ternary, and olivine-based material forces 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. Ni-based LiNiO, LiNiO partially substituted with Co or Mn

twenty two

(Eg LiNiCoO, LiNiMnO, etc.) or those substituted with Co and Mn (eg

twenty two

LiNiMnCoO, etc., or substituted with Co and A1 (eg LiNiCoAlO)

2 2 etc.) or those substituted with other transition metals (eg LiNiCoAlMO).

2 As a ternary system, the ratio of Ni, Mn, and Co is 1: 1: 1.

1/3 1/3 1/3 2 and so on. For olivine, LiMPO (M = Fe, M

4 4

n, Co, Ni).

[0020] 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 as described above, metal materials, and lithium metal alloy materials. Use these alone Mogoku 2 or more types may be used in combination.

[0021] The average particle diameter of each active material contained in each active material layer is not particularly limited, but is preferably 0.01-: LOO μm, more preferably 1-50 μm. In this specification, “particle diameter” means the maximum distance L of the distance between any two points on the particle outline, and the value of “average particle diameter” is Using an observation means such as a scanning electron microscope (SEM) or transmission electron microscope (TEM), the value calculated as the average value of the particle diameters observed in several to several tens of fields shall be adopted. .

[0022] 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.

[0023] The conductive additive refers to an additive that is mixed 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.

[0024] As electrolyte salts (lithium salts), Li (C F SO) N, LiPF, LiBF, LiCIO, LiAsF

2 5 2 2 6 4 4 6

, LiCF SO

3 3 etc. The electrolyte is described in detail in the section “Electrolyte” below.

[0025] The mixing ratio of the components contained in the positive electrode active material layer and the negative electrode active material layer is not particularly limited. The mixing ratio can be adjusted by appropriately referring to known knowledge about the non-aqueous electrolyte secondary battery.

[0026] In the present embodiment, the thickness of each active material layer is not less than 30 m and not more than 300 m. When the capacity per unit cell is increased, the active material layer is preferably thicker. However, when the active material layer is thicker, the adhesion between the materials of the active material layer may decrease when a conventional binder is used. In some cases, the amount of binder added must be increased. On the other hand, by using the binder of this embodiment, even when the thickness of the active material layer is as thick as 30 m or more, the amount of the active material layer without increasing the blending amount of the binder is increased. Adhesion 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.

[0027] The amount of the binder in the active material layer is not particularly limited, but may be 5 to 50%. More preferably, it is 5 to 20%. If it is in this range, the decrease in energy density can be prevented, which is preferable.

[0028] [Current collector (including outermost current collector)]

The current collector and the outermost layer current collector also have conductive material strength such as aluminum foil, copper foil, and stainless steel (abbreviated as SUS in Japanese Industrial Standards) foil. The typical thickness of the current collector is 1-30 πι.

[0029] 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 to be produced, a current collector with a large area is used. If a small electrode is produced, a current collector with a small area is used.

[0030] [Production method]

The electrode of this embodiment can be manufactured by a conventionally known method for manufacturing a non-aqueous electrolyte secondary battery electrode. For example, an active material and a thermosetting resin are added to an organic solvent to prepare an active material slurry, and the active material slurry is applied to the surface of the current collector to form a coating film. Can be done. Specifically, a desired active material and thermosetting resin, and other components (e.g., conductive assistant, supporting salt (lithium salt), ion conductive polymer, etc.) in a solvent as required. To prepare an active material slurry. The kind of solvent and the mixing means are not particularly limited, and conventionally known knowledge can be appropriately referred to for electrode production. As an example of the solvent, Ν-methyl-2-pyrrolidone (ΝΜΡ), 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.

[0031] (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 battery life. 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 preferable to use at least the positive electrode and the negative electrode. It is more preferable to use both. [0032] In the nonaqueous secondary battery of the present invention, in addition to the electrode elements of the first embodiment, normally known electrode components are used. Hereinafter, members constituting the battery of this embodiment will be described.

[0033] [Separator]

The separator used in the present invention is not particularly limited, and may be a non-woven fabric separator or a microporous membrane separator.

[0034] As the nonwoven fabric separator, for example, a sheet entangled with fibers can be used. Further, a spunbond obtained by fusing fibers together by heating can also be used. That is, 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 with an appropriate adhesive or a fusion bond of the fibers themselves. The fibers used are not particularly limited, for example, polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate (PET), cellulose, rayon, acetate, nylon (registered trademark), polyimide, aramid, ceramics, etc. A conventionally well-known thing can be used.

[0035] As the microporous membrane separator, for example, a porous sheet (for example, a polyolefin microporous membrane separator, etc.) having a polymer force for absorbing and holding the electrolyte can be used. The polyolefin microporous membrane separator having the property of being chemically stable to an organic solvent has an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low. Examples of the material for the polyolefin microporous membrane separator include a laminate having a three-layer structure of polyethylene (PE), polypropylene (PP), and PPZPEZPP. In addition, examples of the material for the microporous membrane separator include polyimide, aramid, and polyethylene terephthalate.

[0036] The material constituting the separator used in the present embodiment preferably includes at least one material selected from polypropylene, polyimide, polyethylene terephthalate (PET), aramid, cellulose, and a ceramic force. 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 still more preferably 100%. Also, above The preferred materials may be used alone or in combination of two or more, but are preferably used alone from the viewpoint of productivity.

[0037] The separator described above is sandwiched between 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 can be wrapped in an exterior material and used as it is as a nonaqueous electrolyte secondary battery, or multiple sets can be stacked and wrapped in an exterior material to be used as a nonaqueous electrolyte secondary battery. Good.

[0038] Preferably, when the material is used, the high temperature durability is further improved by the combination with a specific binder used in the active material layer. Specifically, (a) the material constituting the separator includes polyimide and the binder includes thermosetting polyimide; (b) the material force constituting the separator includes at least one of SPET and aramid, Preferred examples include a form containing at least one of phenolic resin and epoxy resin; (c) a material comprising the separator contains polypropylene and a binder contains at least one of phenolic resin and epoxy resin. The The form of (a) to (c) may be a combination of at least one of a positive electrode and a negative electrode, and a separator. However, since the effects of the present invention are remarkably obtained, both the positive electrode and the negative electrode are formed. A combination of a binder and a separator is more preferable.

[0039] [Insulating fine particle mixed material]

In the present embodiment, an insulating fine particle mixed material including 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. Preferably it is. By disposing the insulating fine particle mixed material, the heat resistance is further improved and the high temperature durability is further improved. In addition, by using a thermosetting binder, the insulating fine particles can be adhered well even at high temperatures.

[0040] "Insulating fine particles" mean particles that exhibit electrical insulation. The material constituting the insulating fine particles is not particularly limited as long as it is a material exhibiting electrical insulation, and conventionally known materials can be appropriately used. Specifically, a ceramic material or an organic polymer material can be used as a material constituting the insulating fine particles. Insulating fine particles composed of these materials By doing so, the function of preventing the short circuit between the positive and negative electrodes required for the separator can be sufficiently exhibited.

[0041] Examples of these insulating fine particles include lithium ferrite (LiFeO) and silica (SiO2).

twenty two

), Anolemina (Al 2 O 3), zirconia, magnesia, titania, silica anolemina, acid chrome,

twenty three

Acids such as ruthenium oxide, nitrides such as aluminum nitride and silicon nitride, acrylic materials such as LiFe PO, polymethyl acrylate and polymethyl methacrylate, fluorinated imides

Four

Examples thereof include polyimide materials such as polystyrene, polypropylene, polysulfone, phenol resin, and unsaturated polyester resin. Among these materials, LiFeO, SiO in terms of electronic conductivity (insulation) and mechanical strength (having a higher short-circuit prevention function)

twenty two

AlO is preferably used. These materials may be used alone, or two or more

twenty three

You may use together.

[0042] The insulating fine particles may be all particles (ceramic particles) made of a ceramic material, or all particles (organic polymer particles) made of an organic polymer material. However, it may be a mixture of these particles. When the form of the mixture is adopted, the mixing ratio of the ceramic particles and the organic polymer particles is not particularly limited. However, the ratio (volume ratio) of the ceramic particles to the organic polymer particles is preferably 10 to 20: 1. -10, more preferably 10-15: 3-10.

In this embodiment, the average particle size of the insulating fine particles is 微粒子 ηπ! More preferably, it is 50 nm to 25 μm, more preferably 100 nm to 20 μm, and most preferably 1000 nm to 10 m. If the insulating fine particles are in 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 particles of such a relatively small size are used. By using conductive fine particles, the occurrence of a short circuit between the positive and negative electrodes can be sufficiently suppressed.

[0044] In this embodiment, the insulating fine particles are bound to each other by the thermosetting adhesive contained in the insulating fine particle mixed material, and the adhesion between the separator and the active material layer is achieved. Sex can also be improved. As a result, the reliability such as vibration resistance of the nonaqueous electrolyte secondary battery can be improved. Thermosetting adhesives include urea resin, epoxy resin, polyurethane Examples of the resin include cocoa resin, key 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. When the total amount of the insulating fine particle mixed material is 100%, it is preferably 1 to 80%, more preferably 3 to 50%. When the added amount of the adhesive is within such a range, a battery having an excellent balance of binding property, adhesion, and volumetric energy density can be provided.

[0046] 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 the insulating fine particle mixed material is applied to the surface of the active material layer, it is preferable to apply 70% or more with respect to 100% of the area of the active material layer. 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.

[0047] The solvent used in preparing the insulating particle slurry is not particularly limited, and specifically, polar solvents such as N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, and methylformamide. Is mentioned.

[0048] 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. OPa's, and more preferably 1.0 to 4. OPa's.

[0049] 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 method 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.

[0050] The insulating particle slurry applied to the surface of the active material layer may be dried and heated!

Heating may be performed after application of the insulating particle slurry and before lamination of the electrodes, or after lamination. In a preferred embodiment, heating is performed after the electrodes are stacked. According to such a form, an effect of improving the adhesion of the active material layer, the separator, and the insulating particle mixed material can be obtained in addition to improving the binding property of the insulating particles.

[0051] [Electrolyte] 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 electrolyte include lithium salts such as LIB ETI, LiBF, LiPF, LiN (SO CF), and LiN (SO CF).

4 6 2 3 2 2 2 5 2

The Examples of the solvent include carbonates such as propylene carbonate (PC), ethylene carbonate (EC), dimethylolate carbonate (DMC), jetinolecarbonate (DEC), and ethinoremethyl carbonate (EMC). It is done. When these electrolytes are used as electrolytes for non-aqueous secondary batteries, they are used in the separator.

[0052] The polymer electrolyte is composed of an ion conductive polymer, and the material is not limited as long as it exhibits ion conductivity. A polymer ion-conductive polymer that is crosslinked by thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, or the like is preferably used because it can exhibit excellent mechanical strength. It is done.

[0053] Examples of the polymer electrolyte include an intrinsic polymer electrolyte and a gel polymer electrolyte. Intrinsic polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0054] Further, the gel polymer electrolyte generally refers to an electrolyte solution held in an all-solid polymer electrolyte having ion conductivity. In the present application, the gel polymer electrolyte also includes a polymer skeleton that does not have 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.

[0055] [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 include aluminum, copper, titanium, nickel, stainless steel (abbreviated as SUS in the Japanese Industrial Standards), and alloys thereof.

[0056] [Exterior material]

The exterior material is not particularly limited, and a conventionally known exterior material can be used. The ability to easily cool the heat from the heat source of an automobile or the heat generated by the battery's self-heating due to a high load In addition, a polymer metal composite laminate sheet having excellent thermal conductivity is preferably used because heat can be efficiently transferred from the heat source of the automobile during cold start and the inside of the battery can be quickly heated to the battery operating temperature. sell. 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 element electrode terminals at atmospheric pressure, and it is possible to further reduce the contact resistance.

[0057] The nonaqueous electrolyte secondary battery of the present embodiment can be manufactured by appropriately referring to conventionally known knowledge without using a special technique.

[0058] The nonaqueous electrolyte secondary battery of the present invention is not particularly limited as long as it is a battery using a nonaqueous electrolyte, but is preferably a lithium ion secondary battery from the viewpoint of practicality. .

[0059] The non-aqueous electrolyte secondary battery of the present invention may be in a conventionally known form, not particularly limited in structure or connection form. For example, the structure of the battery includes a stacked (flat) battery, a wound (cylindrical) battery, and the like. In addition, electrical connection forms (electrode structures) in the battery include internal series connection (bipolar type) and internal parallel connection.

[0060] (Third embodiment)

In the third embodiment, an assembled battery is configured by connecting a plurality of the nonaqueous electrolyte secondary batteries of the second embodiment described above in parallel and Z or in series.

[0061] The connection method for connecting a plurality of nonaqueous electrolyte secondary batteries constituting the assembled battery is not particularly limited, and a conventionally known method can be appropriately employed. For example, a technique using welding such as ultrasonic welding or spot welding, or a technique of fixing using rivets or caulking can be employed. According to the powerful connection method, the long-term reliability of the assembled battery can be improved.

[0062] According to the assembled battery of the present embodiment, by using the nonaqueous electrolyte secondary battery of the second embodiment as an assembled battery, capacity characteristics are sufficiently ensured under high output conditions. It is possible to provide an assembled battery capable of exhibiting sufficient output.

[0063] It should be noted that all of the non-aqueous electrolyte secondary batteries constituting the assembled battery may be connected in parallel, or all of the non-aqueous electrolyte secondary batteries may be connected in series. And parallel connection may be combined.

[0064] (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. Vehicles that use non-aqueous electrolyte secondary batteries or assembled batteries as power sources for motors, for example, do not use gasoline! /, Hybrid vehicles such as fully electric vehicles, series hybrid vehicles and parallel hybrid vehicles, and fuel cell vehicles Examples include automobiles that drive wheels with motors. The nonaqueous electrolyte secondary battery of the second embodiment or the assembled battery of the third embodiment is excellent in high temperature durability, so it is possible to place the battery even in the vicinity of components that are likely to become high temperature. From the viewpoint of vehicle mountability, it is preferable to use the nonaqueous electrolyte secondary battery or the assembled battery of the present invention for the vehicle.

[0065] Although several preferred embodiments of the present invention have been described above, 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. It is.

Example

[0066] 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 “%”.

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

[0068] (1) Preparation of positive electrode ink

The positive electrode ink was prepared as follows. 70% LiMn O (accumulating and desorbing Li ions

twenty four

Active material, average particle size 10 μm), 20% acetylene black, 5% PVdF and 5% one-component epoxy resin (bisphenol A type epoxy resin) as binder, And 41% of NMP (N-methyl-2-pyrrolidone) as a solvent was added to 100% of the mixture, and the mixture was stirred well to prepare a slurry.

[0069] (2) Preparation of negative electrode ink

The negative electrode ink was produced as follows. 85% amorphous carbon (negative electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 7.5% PVdF and binder 7. Mix 5% one-component epoxy resin (bisphenol A type epoxy resin), add 41% NMP as a solvent to 100% of the mixture, and mix well to prepare slurry. Made.

[0070] (3) Application (electrode preparation)

Positive and negative electrodes: An aluminum foil of about 10 m was used as a current collector, and positive electrode ink was applied to both sides of the aluminum foil as a positive electrode. About 10 m of copper foil was used as the current collector, and the negative electrode was coated with negative ink on both sides of this copper foil. Thereafter, drying was performed at 120 ° C., and 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.

[0071] (4) Terminal lead

A1 plate with a thickness of 150 μm, width 40 mm, and length 50 mm is used for the positive terminal lead, and Ni plating is applied to the Cu plate with thickness 150 / ζ πι, width 40 mm, length 50 mm for the negative terminal lead. The terminal lead that was used was used.

[0072] (5) Assembly

A positive electrode and a 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 (a PET film for surface protection on the outermost layer). A1 foil as a metal film layer and a laminate film in which the heat-fusing insulating film layer is made of polypropylene), and the positive current collector and the negative current collector are protruded from the opposing side forces of the separator, A1 electrode terminals and Ni terminal leads are welded, sandwiched between outer laminate films, the positive and negative terminals projecting from the opposite sides of the battery, the edges are heated and welded, and the electrolyte is applied. The solution was poured to prepare a laminated exterior flat battery with a width of 100 mm x length of 150 mm x thickness of about 3 mm.

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

[0074] (1) Preparation of positive electrode ink

The positive electrode ink was prepared as follows. 70% LiMn O (average particle size 10 m), 20

twenty four

% Acetylene black and 3% PVdF as a binder and 7% one-part epoxy resin (bisphenol A type epoxy resin). Then, 41% of NMP was added as a solvent, and stirred well to prepare a slurry.

[0075] (2) Preparation of negative electrode ink

The negative electrode ink was produced as follows. 85% amorphous carbon with an average particle size of 10 m and binder, 4.5% PVdF and 10.5% one-component epoxy resin (bisphenol A type epoxy resin). After mixing, 41% of NMP was added as a solvent to 100% of the mixture, and stirred well to prepare a slurry.

[0076] (3) Production of battery

In the same manner as in Example 1 (3) to (5), a laminated exterior flat battery was produced. The separator used was a polypropylene microporous membrane separator as in Example 1, V.

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

[0078] (1) Preparation of positive electrode ink

twenty four

% Acetylene black and 10% one-component epoxy resin (bisphenol A type epoxy resin) as a binder, and 41% of NMP was added as a solvent to 100% of the mixture. The slurry was prepared by thorough stirring.

[0079] (2) Create negative electrode ink

The negative electrode ink was produced as follows. 85% amorphous carbon (average particle size 10 m) and 15% one-component epoxy resin (bisphenol A type epoxy resin) as a noinder are mixed, and 100% of the mixture is mixed. Then, 41% of NMP was added as a solvent and sufficiently stirred to prepare a slurry.

[0080] (3) Battery fabrication

Thermosetting resin (polyimide or bisphenol) relative to the total binder mass in the electrode

A slurry was prepared as follows so that the ratio of A-type epoxy resin was 70%. [0082] (1) Preparation of positive electrode ink

twenty four

% Acetylene black, 3% PVdF as a binder, and 7% polyimide resin are mixed, and 41% NMP is added as a solvent to 100% of the mixture, and the mixture is sufficiently stirred to form a slurry. Prepared.

[0083] (2) Preparation of negative electrode ink

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

[0084] (3) Battery fabrication

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

(1) Preparation of ink

In the same manner as in Example 4 (1) and (2), positive and negative electrode inks were produced.

[0086] (2) Battery fabrication

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

(1) Preparation of ink

[0088] (2) Battery fabrication

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

A slurry was prepared as follows so that the ratio of thermosetting resin (phenol resin) to the total amount of binder in the electrode was 70%. [0090] (1) Preparation of positive electrode ink

twenty four

% Acetylene black, 3% PVdF binder and 7% phenol resin are mixed, and 41% NMP is added as a solvent to 100% of the mixture to prepare a slurry. did.

[0091] (2) Preparation of negative electrode ink

The negative electrode ink was produced as follows. Mix 85% amorphous carbon (average particle size 10 m) with 4.5% PVdF and 10.5% phenol resin as binders. A slurry was prepared by adding 41% NMP as a solvent and stirring well.

[0092] (3) Battery fabrication

(1) Ink production

In the same manner as in Example 7 (1) and (2), positive and negative electrode inks were produced.

[0094] (2) Production of battery

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.

[0096] (1) Preparation of positive electrode ink

twenty four

% Acetylene black and 3% PVdF as a binder and 7% one-part epoxy resin (bisphenol A type epoxy resin), and NMP as a solvent for 100% of the mixture. 41% was added and stirred well to prepare a slurry.

[0097] (2) Preparation of negative electrode ink The negative electrode ink was produced as follows. 85% amorphous carbon (average particle size 10 m), 4.5% PVdF as binder and 10.5% one-component epoxy resin (bisphenol A type epoxy resin), Were mixed, 41% of NMP was added as a solvent to 100% of the mixture, and stirred well to prepare a slurry.

[0098] (3) Application (electrode preparation)

As the positive electrode, an aluminum foil of about 10 m 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 of about 10 m was used for the current collector, and the negative electrode was coated with negative ink on both sides of the copper foil. A mixture of 70% alumina particles with a particle size of 1 μm as ceramic fine particles, 10% of one-part epoxy resin (bisphenol A type epoxy resin) as thermosetting adhesive, and NMP as solvent. Was applied on the positive electrode active material by a die coater method with a thickness of 5 / zm. Thereafter, drying was performed at 120 ° C., and 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.

[0099] (4) Production of battery

A laminated exterior flat battery was produced in the same manner as in (4) to (5) of Example 1.

(1) Ink creation

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

[0100] (2) Application (electrode preparation)

The same procedure as in Example 1 was performed except that the pressing was performed such that the thickness of the active material layer after pressing was 30 μm for the positive electrode and 33 μm for the negative electrode.

[0101] (3) Battery fabrication

(1) Ink creation

[0102] (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. [0103] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation

[0105] (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.

[0106] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation

[0108] (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.

[0109] (3) Fabrication of battery

It was produced in the same manner as (4) to (5) in Example 1.

[0110] Example 14>

(1) Create positive ink

twenty four

Active material, average particle size 10 m), 15% acetylene black, binder 7.5% PVdF and 7.5% one-component epoxy resin (bisphenol A type epoxy resin) And 41% of NMP (N-methyl-2-pyrrolidone) as a solvent with respect to 100% of the mixture, and stirred well to prepare a slurry.

[0111] (2) Preparation of negative electrode ink

The negative electrode ink was produced as follows. 80% amorphous carbon (negative electrode active material capable of absorbing and desorbing Li ions, average particle size 10 μm), 10% PVdF as binder and 1 0% one-component epoxy resin (bisphenol A type epoxy resin) is mixed, and 41% of NMP is added as a solvent to 100% of the above mixture to prepare a slurry. did.

[0112] (3) Application (electrode preparation)

About 10 m of aluminum foil was used as the current collector, and positive electrode ink was applied to both sides of this aluminum foil. The current collector was a copper foil of about 10 m and the negative electrode was coated with negative ink on both sides of the copper foil. Then, it dried at 120 degreeC and pressed so that the thickness after a press might be 300 m of positive electrodes, and 280 micrometers of negative electrodes.

[0113] (4) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

[0114] Example 15>

(1) Ink creation

In the same manner as in Example 2 (1) to (2), positive and negative inks were prepared.

[0115] (2) Application (electrode preparation)

[0116] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

[0117] Example 16>

(1) Ink creation

[0118] (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.

[0119] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation In the same manner as in Example 2 (1) to (2), positive and negative inks were prepared.

[0121] (2) Application (electrode preparation)

[0122] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

[0123] <Example 18>

(1) Ink creation

[0124] (2) Application (electrode preparation)

[0125] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Create positive ink

twenty four

Active material, average particle size 10 m), 15% acetylene black, binder 4.5% PVdF and 10.5% one-component epoxy resin (bisphenol A epoxy) Fat) and 41% of NMP (N-methyl-2-pyrrolidone) as a solvent was added to 100% of the mixture, and stirred well to prepare a slurry.

(2) Creating negative electrode ink

The negative electrode ink was produced 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-component epoxy resin (bisphenol) A type epoxy resin) was mixed, and 41% of NMP was added as a solvent to 100% of the mixture to prepare a slurry.

[0127] (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.

[0128] (4) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Create positive ink

A positive electrode ink was produced in the same manner as in Example 3 (1).

[0130] (2) Create negative electrode ink

[0131] (3) Application (electrode preparation)

[0132] (4) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation

In the same manner as in Example 20 (1) and (2), positive and negative inks were prepared.

[0134] (2) Application (electrode preparation)

[0135] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation

In the same manner as in Example 20 (1) and (2), positive and negative inks were prepared. [0137] (2) Application (electrode preparation)

[0138] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

(1) Ink creation

[0140] (2) Application (electrode production)

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.

[0141] (3) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

[0142] <Example 24>

(1) Ink creation

The positive electrode ink was prepared as follows. 70% LiMn O (average particle size 10 m), 15

twenty four

% Acetylene black and 15% one-component epoxy resin (bisphenol A type epoxy resin) as a binder, and 41% of NMP was added as a solvent to 100% of the mixture. The slurry was prepared by thorough stirring.

[0143] (2) Create negative electrode ink

The negative electrode ink was produced 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) was mixed, and 41% of NMP was added as a solvent to 100% of the mixture to prepare a slurry with sufficient stirring

[0144] (3) Application

Positive and negative electrodes: An aluminum foil of about 10 m was used as a current collector, and positive electrode ink was applied to both sides of the aluminum foil as a positive electrode. About 10 m of copper foil is used for the current collector, and negative What applied polar ink was made into the negative electrode. Then, it dried at 120 degreeC and pressed so that the thickness of the active material layer after a press might be 270 micrometers of positive electrodes, and 300 micrometers of negative electrodes.

[0145] (4) Battery fabrication

It was produced in the same manner as (4) to (5) in Example 1.

[0146] <Comparative Example 1>

(1) Create positive ink

twenty four

Acetylene black mass ^_0/0, and 10% of PVdF as a binder were mixed, to the mixed compound of 100%, was added NMP 41% to prepare a well stirred with a slurry as a solvent.

[0147] (2) Create negative electrode ink

The negative electrode ink was produced as follows. Mix 85% amorphous carbon (average particle size 10 m) and 15% PVdF as a noinder, and add 41% NMP as a solvent to 100% of the mixture. A slurry was prepared by stirring.

[0148] (3) Battery fabrication

In the same manner as in Example 1 (3) to (5), a laminated exterior flat battery was produced.

[0149] Table 1 shows a summary of the ratio, type, thickness of the active material layer, and separator material of the thermosetting resin in the nozzles of the examples.

[0150] [Table 1]

Thermosetting resin ^ Thermosetting resin Active material layer thickness (m)

Mass (%) Positive electrode Negative electrode Positive electrode Negative electrode

1 50 Epoxy resin Epoxy resin 60 65 Polypropylene

2 70 Epoxy resin Epoxy resin 60 65 Polypropylene

3 100 Epoxy resin Epoxy resin 60 65 Polypropylene

4 70 Polyimide Epoxy resin 60 65 Polyimide

5 70 Poly S-epoxy resin 60 65 PET

6 70 Polyimide Epoxy resin 60 65 Caramide

7 70 Phenolic resin Phenolic resin 60 65 PET

8 70 Phenolic resin Phenolic resin 60 65 Caramide

9 70 Epoxy resin Epoxy resin 60 65 Polypropylene

10 50 Epoxy resin Epoxy resin 30 33 Polypropylene

1 1 50 Epoxy resin Epoxy resin 100 1 10 Polypropylene Actual

12 50 Epoxy resin Epoxy resin 150 165 Polypropylene

13 50 Epoxy resin Epoxy resin 200 220 Polypropylene Example 14 50 Epoxy resin Epoxy resin 300 280 Polypropylene

15 70 Epoxy resin Epoxy resin 30 33 Polypropylene

16 70 Epoxy resin Epoxy resin 100 1 10 Polypropylene

17 70 Epoxy resin Epoxy resin 150 165 Polypropylene

18 70 Epoxy resin Epoxy resin 200 220 Polypropylene

19 70 Epoxy resin Epoxy resin 300 280 Polypropylene

20 100 Epoxy resin Epoxy resin 30 33 Polypropylene

21 100 Epoxy resin Epoxy resin 100 1 10 Polypropylene

22 100 Epoxy resin Epoxy resin 150 1 65 Polypropylene

23 100 Epoxy resin Epoxy resin 200 220 Polypropylene

24 100 Epoxy resin Epoxy resin 270 300 Polypropylene Ratio ： Example ―--60 65 Polypropylene

[0151] <Endurance evaluation>

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

[0152] [Table 2]

(Partial resistance increase rate)%

[0153] [Table 3]

[0154] <Peel strength evaluation>

Cut the electrode produced in the comparative example and the example into a 10mm wide and 50mm long test piece, apply tape to the electrode (active material), and measure the T peel strength at normal temperature (25 ° C) and tensile speed 200mmZmin. did. Tables 4 and 5 show the results of each example when the strength of the comparative example is 1.

[0155] [Table 4] Peel strength Τ

[0156] [Table 5]

[0157] 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

The scope of the claims

[1] current collector;

An active material layer including an active material and a binder disposed on the surface of the current collector, and a nonaqueous electrolyte secondary battery electrode comprising:

The binder is at least one thermosetting resin selected from the group consisting of epoxy resin, phenol resin, and polyimide, with respect to the total mass of the binder, 50 to: LO

Including 0% by mass, the thickness of the active material layer is not less than 30 m and not more than 300 m.

[2] The electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the thickness of the active material layer is 50 m or more and 200 m or less.

[3] A nonaqueous electrolyte secondary battery comprising the electrode according to claim 1 or 2.

[4] A nonaqueous electrolyte secondary battery comprising a separator sandwiched between the electrodes,

4. The non-aqueous electrolyte secondary battery according to claim 3, further comprising at least one selected from the group strengths of polypropylene, polyimide, polyethylene terephthalate, aramid, cellulose, and ceramics.

5. The nonaqueous electrolyte secondary battery according to claim 4, wherein the binder includes a thermosetting polyimide resin, and the material constituting the separator includes polyimide.

[6] The binder includes at least one of a thermosetting phenolic resin or a thermosetting epoxy resin, and the material strength of constituting the separator is polypropylene, polyethylene terephthalate, and aramid force. The nonaqueous electrolyte secondary battery according to claim 4, comprising:

[7] The insulating fine particle mixed material containing a thermosetting adhesive and insulating fine particles is disposed between the active material layer and the separator. The nonaqueous electrolyte secondary battery of description.

[8] The material constituting the insulating fine particles is selected from Al O, SiO and LiFeO.

2 3 2 2

The nonaqueous electrolyte secondary battery according to claim 7, comprising:

[9] The non-aqueous electrolyte secondary battery according to any one of claims 3 to 8, wherein the positive electrode active material includes at least one selected from the group force of Ni-based, ternary-based, and olivine-based material forces .

[10] An assembled battery using the nonaqueous electrolyte secondary battery according to any one of claims 3 to 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.