JP2013254634A - Lithium ion secondary battery manufacturing method, and component for lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery manufacturing method capable of restraining increase of labors and costs required for manufacturing a battery, maintaining a battery performance required for a lithium ion secondary battery, and sufficiently restraining displacement or exfoliation of a separator and an electrode and/or electrodes by improving adhesiveness of the separator and the electrode and/or the electrodes.SOLUTION: The method for manufacturing a lithium ion secondary battery comprising a positive electrode containing one or more kinds of materials selected from a group of materials that can occlude and emit lithium ions as a positive active material; and a negative electrode containing one or more kinds of materials selected from a group of the materials that can occlude and emit lithium ions as a negative active material, and metallic lithium includes steps of: providing a low molecular gelatinizer on a surface of at least one part of one or more kinds of members selected from a group of the positive electrode and the negative electrode by a high molecular binder; laminating the positive electrode and the negative electrode to obtain a laminate containing them; and immersing the laminate with an electrolyte.

Description

  The present invention relates to a method for producing a lithium ion secondary battery and a component for a lithium ion secondary battery.

  With the recent development of electronic technology and increasing interest in environmental technology, various electrochemical devices are used. In particular, there are many requests for energy saving, and expectations for what can contribute to it are increasing. For example, a solar cell is mentioned as a power generation device, and a secondary battery, a capacitor, a capacitor, etc. are mentioned as an electrical storage device. Lithium ion secondary batteries, which are representative examples of power storage devices, have been conventionally used mainly as rechargeable batteries for portable devices, but in recent years, they are also expected to be used as batteries for hybrid vehicles and electric vehicles.

A typical lithium ion secondary battery as an electricity storage device generally has a configuration in which a positive electrode and a negative electrode mainly composed of an active material capable of inserting and extracting lithium are arranged via a separator. The positive electrode of the lithium ion secondary battery includes LiCoO ₂ , LiNiO ₂ or LiMn ₂ O ₄ as a positive electrode active material, carbon black or graphite as a conductive agent, and polyvinylidene fluoride, latex or rubber as a binder. Is formed by covering a positive electrode current collector made of aluminum or the like. The negative electrode is formed by coating a negative electrode mixture made of copper or the like with a negative electrode mixture in which coke or graphite as a negative electrode active material and polyvinylidene fluoride, latex or rubber as a binder are mixed. The The separator is made of porous polyolefin or the like, and its thickness is very thin, from several μm to several hundred μm. The positive electrode, the negative electrode, and the separator are immersed in the electrolytic solution in the battery. Examples of the electrolytic solution include an electrolytic solution in which a lithium salt such as LiPF ₆ or LiBF ₄ is dissolved in an aprotic solvent such as propylene carbonate or ethylene carbonate, or a polymer such as polyethylene oxide.

Currently, lithium ion secondary batteries are mainly used as rechargeable batteries for portable devices (see, for example, Patent Document 1). In recent years, it has also begun to be used as a battery for automobiles such as hybrid cars and electric cars, and the use and market of lithium ion secondary batteries tend to be further greatly expanded. Examples of conventional lithium ion batteries include those described in Patent Documents 2, 3, and 4.
On the other hand, for the purpose of improving the safety of lithium ion secondary batteries, development of polymer electrolytes typified by polyethylene oxide and polymer gel electrolytes has been actively promoted. These are considered useful in terms of improving battery safety and increasing the degree of freedom of battery shape that can be produced.

JP 2009-087648 A JP 2007-157469 A JP 2007-157570 A JP-A-10-177865

Among lithium ion secondary batteries, those used for automobiles need to produce a larger amount of larger batteries than before, and demands for improvement in productivity, production and stabilization of quality are higher. However, the current lithium ion secondary battery has a problem that the arrangement of the electrodes and the separator is shifted from each other, the electrodes and the separator are separated from each other, and the electrodes are easily shifted from each other. If the electrode or separator is misplaced or peeled off, charging / discharging may not be performed properly, overcharging or overdischarging may occur, a predetermined battery capacity may not be obtained, or the battery may be short-circuited. This may shorten the battery life.
In addition, since the electrode expands and contracts during charge and discharge in a lithium ion secondary battery, the arrangement of the electrode and the separator is easily shifted depending on the behavior, and even if it is properly disposed in the initial stage of battery assembly, It may be displaced or peeled off.

  Possible means for solving such problems are, for example, the means disclosed in Patent Documents 2 and 3 for improving the separator surface to make it easier to bond the separator and the electrode, and considering the deviation. Examples include means using an electrode and a separator having a size and shape, and means using an adhesive material such as an adhesive as described in Patent Document 4.

However, these means increase labor and cost required for manufacturing the battery, extremely reduce other performance required for the lithium ion secondary battery, and do not sufficiently suppress the displacement of the arrangement. As a result, no satisfactory solution has yet been found.
In addition, it is known that when a polymer electrolyte or a polymer gel electrolyte is used, the interfacial adhesion between the electrode layer and the separator or electrodes is improved to some extent. However, these electrolytes have insufficient charge / discharge characteristics, and there is still room for improvement in practical use.

  Therefore, the present invention has been made in view of the above circumstances, and can suppress an increase in labor and cost required for the production of the battery, while maintaining the battery performance required for the lithium ion secondary battery, and between the separator and the electrode. Lithium ion secondary battery manufacturing method and lithium ion secondary battery component that sufficiently suppresses displacement and peeling of each other by improving adhesion and / or adhesion between electrodes The purpose is to provide.

  As a result of studying various battery parts to achieve the above object, the present inventors used a part in which a low molecular gelling agent is present on the surface by a polymer binder as a separator and / or an electrode. It has been found that the adhesion between the separator and the electrode and / or the adhesion between the electrodes is improved, and the present invention has been completed.

式（３）中、Ｒ⁵は主鎖の炭素数１〜２０の置換又は無置換の１価の炭化水素基を示し、Ｃｙは置換若しくは無置換の核原子数５〜３０の２価の芳香族炭化水素基又は脂環式炭化水素基を示し、Ｘ³は、下記式（３ａ）、（３ｂ）、（３ｃ）、（３ｄ）、（３ｅ）、（３ｆ）及び（３ｇ）で表される基からなる群より選ばれる２価の基、又は、それらの２価の基のうち２種以上が結合した２価の基を示し、Ｃｍは下記一般式（３ｚ）で表される１価の基を示し、下記式（３ｚ）中、複数のＲ^aはそれぞれ独立に、水素原子、アルキル基、アルコキシ基又はハロゲン原子を示す。

）
［１３］前記Ｘ¹及びＸ²が、それぞれ独立に、前記式（１ａ）又は前記式（１ｄ）で表される２価の官能基である、上記製造方法。
［１４］前記Ｘ¹及びＸ²がいずれも、前記式（１ｄ）で表される２価の基である、上記製造方法。
［１５］前記高分子結着剤が、ハロゲン原子及び（メタ）アクリル基からなる群より選ばれる１種以上を有するポリマーである、上記製造方法。
［１６］前記高分子結着剤が、ポリフッ化ビニリデン部位を有するポリマー、（メタ）アクリロニトリル部位を有するポリマー、及び（メタ）アクリル酸エステル部位を有するポリマーからなる群より選ばれる１種以上を含む、上記製造方法。
［１７］前記電解液が、非水溶媒と、リチウム塩と、低分子ゲル化剤と、高分子結着剤と、を含む、上記製造方法。
［１８］前記電解液が、所定温度以下の温度でゲルであり、その所定温度よりも高い温度でゾルである相転移型のゲル電解質溶液であり、前記所定温度が５０〜１５０℃の範囲にある、上記製造方法。
［１９］正極、負極及びセパレータからなる群より選ばれる１種以上の部材と、前記部材における少なくとも一部の表面上に存在する低分子ゲル化剤と、を含む、リチウムイオン二次電池用部品。
［２０］高分子結着剤を更に含み、前記低分子ゲル化剤は、前記少なくとも一部の表面に、直接及び／又は前記高分子結着剤を介して付着している、上記リチウムイオン二次電池用部品。 That is, the present invention is as follows.
[1] A positive electrode containing one or more materials selected from the group consisting of materials capable of inserting and extracting lithium ions as a positive electrode active material, and lithium ions can be inserted and extracted as a negative electrode active material And a negative electrode containing one or more materials selected from the group consisting of metallic lithium, and a method for producing a lithium ion secondary battery comprising a polymer binder and the positive electrode and the negative electrode. A step of allowing a low-molecular gelling agent to be present on at least a part of the surface of one or more members selected from the group consisting of: laminating the positive electrode and the negative electrode to obtain a laminate including them; Immersing the laminate in an electrolytic solution.
[2] A separator, a positive electrode containing at least one material selected from the group consisting of materials capable of occluding and releasing lithium ions as a positive electrode active material, and occluding and releasing lithium ions as a negative electrode active material And a negative electrode containing at least one material selected from the group consisting of metallic lithium and a lithium ion secondary battery comprising a separator, A step of causing a low-molecular gelling agent to exist on at least a part of the surface of one or more members selected from the group consisting of the positive electrode and the negative electrode, and laminating the separator between the positive electrode and the negative electrode. And a step of obtaining a laminate including them, and a step of immersing the laminate in an electrolytic solution.
[3] The said manufacturing method in which the said separator contains organic resin.
[4] The production method as described above, wherein in the step of existing, the low-molecular gelling agent is attached to the at least a part of the surface directly and / or via the polymer binder.
[5] The production method as described above, wherein in the step of existing, the composition containing the low-molecular gelling agent and the polymer binder is brought into direct contact with at least a part of the surface of the member.
[6] The above production method, wherein the composition is a solution or a dispersion, and the dispersion is a liquid, a gel, or a slurry.
[7] The production method as described above, wherein in the step of causing the composition to exist, the composition is directly brought into contact with at least a part of the surface of the member by immersing the member in the composition.
[8] In the step of being present, the composition is directly brought into contact with at least a part of the surface of the laminate or the member provided in the structure including the laminate and a battery case containing the laminate. The above manufacturing method.
[9] The above production method, wherein the composition contains a positive electrode active material, and in the step of causing the composition to exist, the composition is brought into direct contact with the surface of the positive electrode current collector or the positive electrode.
[10] The above production method, wherein the composition contains a negative electrode active material, and in the step of causing the composition to exist, the composition is brought into direct contact with the surface of the negative electrode current collector or the negative electrode.
[11] The above production method, wherein the composition further comprises a lithium salt.
[12] The above production method, wherein the low molecular gelling agent comprises one or more compounds selected from the group consisting of compounds represented by the following general formulas (1), (2) and (3).
^{Rf 1 -R 1 -X 1 -L 1} -R 2 (1)
Rf ¹ -R ¹ -X ¹ -L ¹ -R ³ -L ² -X ² -R ⁴ -Rf ² (2)
^{R 5 -O-Cy-X 3} -Cm (3)
(In the formulas (1) and (2), Rf ¹ and Rf ² each independently represents a perfluoroalkyl group having 2 to 20 carbon atoms, and R ¹ and R ⁴ each independently represent a single bond or 1 carbon atom. To 6 divalent saturated hydrocarbon groups, wherein X ¹ and X ² are each independently the following formulas (1a), (1b), (1c), (1d), (1e), (1f) and ( 1g) represents a divalent group selected from the group consisting of groups represented by 1g), L ¹ and L ² are each independently a single bond, an alkyl group or an oxyalkylene group optionally substituted with a halogen atom, an alkyl An oxycycloalkylene group which may be substituted with a group or a halogen atom, or a divalent oxyaromatic group which may be substituted with an alkyl group or a halogen atom, and R ² represents an alkyl group or a halogen atom ( However, A fluoroalkyl group, an aryl group or a fluoro group optionally substituted with an alkyl group having 1 to 20 carbon atoms, an alkyl group or a halogen atom (excluding a fluorine atom) which may be substituted with An aryl group, or a monovalent group in which one or more of these groups and one or more of divalent groups corresponding to these groups are bonded, R ³ represents oxygen and And / or a C1-C18 divalent saturated hydrocarbon group which may have one or more sulfur atoms and may be substituted with an alkyl group.

In formula (3), R ⁵ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms in the main chain, and Cy represents a substituted or unsubstituted divalent aromatic group having 5 to 30 nucleus atoms. It shows the family hydrocarbon group or an alicyclic hydrocarbon group, X ³ is represented by the following formula (3a), (3b), (3c), (3d), (3e), (3f) and (3 g) A divalent group selected from the group consisting of the following groups, or a divalent group in which two or more of these divalent groups are bonded, and Cm is a monovalent group represented by the following general formula (3z) In the following formula (3z), a plurality of R ^a each independently represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.

)
[13] The above production method, wherein X ¹ and X ² are each independently a divalent functional group represented by the formula (1a) or the formula (1d).
[14] The above production method, wherein both of X ¹ and X ² are a divalent group represented by the formula (1d).
[15] The above production method, wherein the polymer binder is a polymer having one or more selected from the group consisting of a halogen atom and a (meth) acryl group.
[16] The polymer binder includes one or more selected from the group consisting of a polymer having a polyvinylidene fluoride moiety, a polymer having a (meth) acrylonitrile moiety, and a polymer having a (meth) acrylic ester moiety. The above manufacturing method.
[17] The above production method, wherein the electrolytic solution contains a non-aqueous solvent, a lithium salt, a low molecular gelling agent, and a polymer binder.
[18] The electrolyte solution is a phase transition type gel electrolyte solution that is a gel at a temperature equal to or lower than a predetermined temperature and is a sol at a temperature higher than the predetermined temperature, and the predetermined temperature is in a range of 50 to 150 ° C. A manufacturing method as described above.
[19] A lithium ion secondary battery component comprising at least one member selected from the group consisting of a positive electrode, a negative electrode, and a separator, and a low-molecular gelling agent present on at least a part of the surface of the member. .
[20] The lithium ion secondary agent further comprising a polymer binder, wherein the low molecular gelling agent is attached to the at least part of the surface directly and / or via the polymer binder. Next battery parts.

  According to the present invention, it is possible to suppress an increase in labor and cost required for battery production, maintain battery performance required for a lithium ion secondary battery, and adherence between a separator and an electrode and / or adhesion between electrodes. By improving the properties, it is possible to provide a method for producing a lithium ion secondary battery and a component for a lithium ion secondary battery, which can sufficiently prevent them from shifting or peeling from each other.

It is sectional drawing which shows roughly an example of the lithium ion secondary battery of this embodiment.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. In the present specification, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto. The manufacturing method of the lithium ion secondary battery of this embodiment includes a positive electrode containing at least one material selected from the group consisting of materials capable of inserting and extracting lithium ions as a positive electrode active material, and a negative electrode active material And a negative electrode containing one or more materials selected from the group consisting of metallic lithium and a material capable of inserting and extracting lithium ions, and a polymer binding A step of causing a low-molecular gelling agent to exist on at least a part of the surface of one or more members selected from the group consisting of a positive electrode, a negative electrode, and optionally a separator, and laminating them; A step of obtaining a laminated body including the step of immersing the laminated body in an electrolytic solution.

<Low molecular gelling agent>
The low molecular gelling agent used in the present embodiment is a general term for compounds having gelling ability other than a polymer (polymer) obtained by polymerizing monomers. In the present invention, supramolecular gelling agents are also included in the low-molecular gelling agents. The low-molecular gelling agent self-assembles one-dimensionally in a solution to form a pseudo polymer (supermolecular fiber), and further entangles them to hold the solvent to form a gel. The molecular weight of the low molecular weight gelling agent is preferably 50 to 10,000, more preferably 100 to 5,000, as measured by gel permeation chromatography from the viewpoint of gelation ability and gel handling. .
The low molecular weight gelling agent is a phase transition type gelling agent capable of forming a gel capable of sol-gel transition by reversible physical interaction from the viewpoint of handling and battery characteristics. Preferably there is. Here, examples of the physical interaction include temperature (heat) change, light irradiation, and pressure application.
The low molecular gelling agent in the present embodiment is not particularly limited. For example, a compound having one or more groups of an amide group, a urea group, and a urethane group, an amino acid derivative, “Chem. Rev. Vol. 97, p3133”. -P3159, issued in 1997 ", compounds described in JP-A-10-175901, compounds described in International Publication No. 2006/82768, described in JP-A-2007-506833 Compounds described in Japanese Patent Application Laid-Open No. 2009-155592, compounds described in “Chem. Mater. 11, p649-655, 1999”, and “J. Phys. Chem. B, 105, p12809-12815, published in 2001 ”. .

    The low-molecular gelling agent may be a mixture of a plurality of gelling agents in order to develop performance such as charge / discharge performance and safety.

The low molecular weight gelling agent used in the present embodiment is composed of compounds represented by the following general formulas (1), (2) and (3) from the viewpoint of electrochemical stability and gelling ability with respect to an electrolyte solution. It is preferable to include one or more compounds selected from the group.
^{Rf 1 -R 1 -X 1 -L 1} -R 2 (1)
Rf ¹ -R ¹ -X ¹ -L ¹ -R ³ -L ² -X ² -R ⁴ -Rf ² (2)
^{R 5 -O-Cy-X 3} -Cm (3)

In the general formulas (1) and (2), Rf ¹ and Rf ² each independently represents a C 2-20 perfluoroalkyl group. When the number of carbon atoms is 2 to 20, it is easy to obtain raw materials and synthesize the compounds. From the viewpoints of the compatibility of the compounds represented by the above general formulas (1) and (2) (hereinafter also referred to as “perfluoro compounds”) into the electrolytic solution, the electrochemical characteristics of the electrolytic solution, and the gelling ability. The carbon number is preferably 2-12. Examples of the perfluoroalkyl group include perfluoroethyl group, perfluoro n-propyl group, perfluoroisopropyl group, perfluoro n-butyl group, perfluoro t-butyl group, perfluoro n-hexyl group, perfluoro n. -An octyl group, a perfluoro n-decyl group, and a perfluoro n-dodecyl group are mentioned.

In the general formulas (1) and (2), R ¹ and R ⁴ each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms, and the carbon number is 2 to 5. It is preferable. When the divalent saturated hydrocarbon group has 3 or more carbon atoms, it may or may not be branched. Examples of such a divalent saturated hydrocarbon group include a methylidene group, an ethylene group, an n-propylene group, an isopropylene group, and an n-butene group.

X ¹ and X ² are each independently selected from the group consisting of groups represented by the following formulas (1a), (1b), (1c), (1d), (1e), (1f) and (1g). The divalent group selected is shown. Among these, from an electrochemical viewpoint, a divalent group selected from the group consisting of groups represented by the following formulas (1a), (1b) and (1d) is preferable, and the following formula (1a) or A divalent group represented by the formula (1d) is more preferable, and a divalent group represented by the following formula (1d) is more preferable.

L ¹ and L ² may each independently be substituted with a single bond, an alkyl group or a halogen atom (that is, may be unsubstituted) an oxyalkylene group, an alkyl group or a halogen atom. A good (ie, unsubstituted) oxycycloalkylene group, or a divalent oxyaromatic group (—OAr) optionally substituted (ie, optionally substituted) with an alkyl group or a halogen atom -; Ar represents a divalent aromatic group. Examples of the oxyalkylene group include an oxyalkylene group having 2 to 10 carbon atoms, more specifically, an oxyethylene group (—C ₂ H ₄ O—) and an oxypropylene group (—C ₃ H ₆ O—). Can be mentioned. Examples of the oxycycloalkylene group include an oxycycloalkylene group having 5 to 12 carbon atoms, and more specifically, an oxycyclopentylene group, an oxycyclohexylene group, and an oxydicyclohexylene group.

  Among these, a divalent oxyaromatic group which may be substituted with an alkyl group or a halogen atom is preferable from the viewpoint of gelling ability and safety improvement of the electrolytic solution. The divalent aromatic group in the divalent oxyaromatic group which may be substituted with an alkyl group or a halogen atom is a cyclic divalent group exhibiting so-called “aromaticity”. This divalent aromatic group may be a monocyclic (preferably carbocyclic) group or a heterocyclic group.

  The monocyclic group has 6 to 30 nuclear atoms, and may be substituted with an alkyl group or a halogen atom as described above, or may not be substituted. Specific examples thereof include a divalent group having a nucleus represented by a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, an anthranylene group, a phenanthrylene group, a pyrenylene group, a chrysenylene group, and a fluoranthenylene group. It is done.

  The heterocyclic group has 5 to 30 nucleus atoms, and may be substituted with an alkyl group or a halogen atom as described above, or may not be substituted. Specific examples thereof include a divalent group having a nucleus represented by a pyrrolene group, a furylene group, a thiophenylene group, a triazolen group, an oxadiazolene group, a pyridylene group, and a pyrimidylene group. Among these, as the divalent aromatic group, a phenylene group, a biphenylene group, or a naphthylene group is preferable. Examples of the alkyl group that is a substituent include a methyl group and an ethyl group, and examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

  The oxycycloalkylene group and the oxyaromatic group include those in which a plurality of rings are connected, and examples of such a group include an oxybiphenylene group, an oxyterphenylene group, and an oxycycloalkylphenylene group.

R ² in the general formula (1) is an alkyl group having 1 to 20 carbon atoms, an alkyl group, or a halogen atom (provided that it may be substituted with an alkyl group or a halogen atom (excluding a fluorine atom)). A fluoroalkyl group, an aryl group or a fluoroaryl group optionally substituted with a fluorine atom, or one or more of these groups and a divalent group corresponding to these groups (for example, alkyl A monovalent group (for example, an aralkyl group in which an alkylene group and an aryl group are bonded) bonded to one or more of an alkylene group corresponding to a group and an arylene group corresponding to an aryl group. More specifically, R ² is methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and n-decyl. C1-C12 alkyl groups represented by group are mentioned. These alkyl groups may or may not be further substituted with an alkyl group or a halogen atom (excluding a fluorine atom).

  As a fluoroalkyl group, a C1-C12 fluoroalkyl group (however, except a perfluoroalkyl group) or a C1-C12 perfluoroalkyl group is preferable. Specific examples of the fluoroalkyl group having 1 to 12 carbon atoms (excluding the perfluoroalkyl group) and the perfluoroalkyl group having 1 to 12 carbon atoms include a trifluoromethyl group, 1,1,1, 2,2-pentafluoroethyl group, 1,1,2,2-tetrafluoroethyl group, 1,1,1,2,2,3,3-heptafluoron-butyl group, 1,1,2,2 , 3,3,4,4,5,5,6,6-dodecafluoro n-hexyl group and 1,1,1,2,2,3,3,4,4,5,5,6,6- A tridecafluoro n-decyl group is mentioned. The fluoroalkyl group may be further substituted with an alkyl group or a halogen atom (excluding a fluorine atom), or may not be substituted.

  As an aryl group, for example, an aryl group having 6 to 12 nuclear atoms represented by a phenyl group, a biphenyl group, and a naphthyl group, and a fluoroaryl group, for example, a monofluorophenyl group, a difluorophenyl group, and a tetrafluorophenyl group. Examples thereof include a fluoroaryl group having 6 to 12 nuclear atoms represented by the group.

R ² represents one or more of the aforementioned alkyl group, fluoroalkyl group, aryl group and fluoroaryl group, and a divalent group corresponding to these groups, that is, an alkylene group, a fluoroalkylene group, an arylene group. A monovalent group in which one or more of a group and a fluoroarylene group are bonded may be used. Examples of such a group include a group in which an alkylene group and a perfluoroalkyl group are bonded (however, this group is also a kind of fluoroalkyl group), a group in which an alkylene group and an aryl group are bonded (aralkyl). Group), a group in which a fluoroalkyl group and a fluoroarylene group are bonded to each other.

R ² is preferably an alkyl group or a fluoroalkyl group from the viewpoint of more effectively and reliably achieving the effects of the present invention, and is an alkyl group having 1 to 12 carbon atoms or a fluoroalkyl group having 1 to 12 carbon atoms (provided that Or a perfluoroalkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms or a fluoroalkyl group having 2 to 10 carbon atoms (provided that perfluoro More preferably, the alkyl group is excluded.

R ³ in the general formula (2) may or may not have one or more oxygen and / or sulfur atoms in the main chain, and may not be substituted with an alkyl group. And a C1-C18 divalent saturated hydrocarbon group. The carbon number is preferably 1 to 16, and more preferably 2 to 14. The gelling ability can also be controlled by the number of carbon atoms in R ³ . Moreover, it is preferable that it is carbon number of the said range from a viewpoint of a synthesis | combination and raw material acquisition.

Examples of the gelling agent having a perfluoroalkyl group represented by the general formula (1) or (2) include Rf ¹ -R ¹ —O—R ² and Rf ¹ —R ¹ —S—R ^2. Rf ¹ -R ¹ -SO ₂ -R ² , Rf ¹ -R ¹ -OCO-R ² , Rf ¹ -R ¹ -O-Ar-O-R ² (where Ar is a divalent aromatic group) are shown. ^{Similarly.), Rf 1 -R 1 -SO} 2 -Ar-O-R 2, Rf 1 -R 1 -SO 2 -Ar-O-Rf 4, Rf 1 -R 1 -SO 2 -Ar —O—Rf ³ —Rf ⁴ (where Rf ³ represents a fluoroalkylene group and Rf ⁴ represents a fluoroalkyl group), Rf ¹ —R ¹ —SO—Ar—O—R ² , Rf ¹ —R ¹ —S—Ar—O—R ² , Rf ¹ —R ¹ —O—R ⁵ —O—R ² (wherein R ⁵ represents an alkylene group), Rf ¹ —R ¹ —CONH—R ² , Rf ¹ -R ^1— SO ₂ —Ar ¹ —O—R ³ —O—Ar ² —SO ₂ —R ⁴ —Rf ² (wherein Ar ¹ and Ar ² each independently represent a divalent aromatic group. . ^{Similarly), Rf 1 -R 1 -O-} Ar 1 -O-R 3 -O-Ar 2 -O-R 4 -Rf 2, Rf 1 -R 1 -SO 2 -Ar 1 -O-R 6 - Examples include compounds represented by the general formula: O—R ⁷ —O—Ar ² —O—R ⁴ —Rf ² (wherein R ⁶ and R ⁷ each independently represents an alkylene group; the same shall apply hereinafter). It is done. More specifically, Rf ¹ and Rf ² are each independently a perfluoroalkyl group having 2 to 10 carbon atoms, R ¹ is an alkylene group having 2 to 4 carbon atoms, Ar is (or Ar ¹ and Ar ² are each Independently, a p-phenylene group or a p-biphenylene group, a compound represented by each of the above general formulas wherein R ² is an alkyl group having 4 to 8 carbon atoms, and a dimer structure thereof, for example, Rf ¹ -R ^1- O—Ar—O—R ² , Rf ¹ —R ¹ —SO ₂ —Ar—O—R ² , Rf ¹ —R ¹ —O—Ar ¹ —O—R ³ —O—Ar ² —O— R ⁴ —Rf ² , Rf ¹ —R ¹ —SO ₂ —Ar ¹ —O—R ⁶ —O—R ⁷ —O—Ar ² —O—R ⁴ —Rf ² are exemplified. It is done.

  In the general formula (3), Cy represents a substituted or unsubstituted divalent aromatic hydrocarbon group or alicyclic hydrocarbon group having 5 to 30 nuclear atoms. The divalent aromatic hydrocarbon group is a cyclic divalent group exhibiting so-called “aromaticity”. The divalent aromatic hydrocarbon group may be a monocyclic group or a heterocyclic group. These divalent aromatic hydrocarbon groups may be substituted with a substituent or may be an unsubstituted one that is not substituted. The substituent of the divalent aromatic hydrocarbon group can be selected from the viewpoint of synthesis and availability of raw materials. Alternatively, the substituent of the divalent aromatic hydrocarbon group can be selected from the viewpoint of the melting temperature and gelling ability of the gelling agent.

The monocyclic group has 6-30 nuclear atoms, may be substituted with a substituent, or may be unsubstituted or unsubstituted. Specific examples thereof include divalent groups having a nucleus represented by a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, an anthranylene group, a phenanthrylene group, a pyrenylene group, a chrysenylene group, and a fluoranthenylene group. It is done.
The heterocyclic group has 5 to 30 nuclear atoms, may be substituted with a substituent, or may be unsubstituted or unsubstituted. Specific examples thereof include a divalent group having a nucleus represented by a pyrrolene group, a furylene group, a thiophenylene group, a triazolen group, an oxadiazolene group, a pyridylene group, and a pyrimidylene group.

The aromatic hydrocarbon group is a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 20 nuclear atoms from the viewpoints of availability of raw materials and ease of synthesis and gelation ability in the electrolytic solution. It is preferably a group selected from the group consisting of a phenylene group, a biphenylene group, a naphthylene group, a terphenylene group and an anthranylene group.
Moreover, as said substituent, the alkyl group represented by the methyl group and the ethyl group, and a halogen atom are mentioned.

  The alicyclic hydrocarbon group may have 5 to 30 substituted or unsubstituted nucleus atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

  An aromatic hydrocarbon group or an alicyclic hydrocarbon group has a combination of a plurality of groups as long as the number of core atoms is within the above range, or has both a simple ring and a heterocyclic ring, or an aromatic group And an alicyclic group. In addition, examples of the substituent of the aromatic hydrocarbon group or the alicyclic hydrocarbon group include an alkyl group typified by a methyl group and an ethyl group, and a halogen atom.

In the general formula (3), R ⁵ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms in the main chain, and may be saturated or unsaturated. R ⁵ may be an aliphatic hydrocarbon group and may further have an aromatic hydrocarbon group. A part or all of the hydrocarbon groups in the aliphatic hydrocarbon group and aromatic hydrocarbon group may be substituted with a halogen atom. When the monovalent hydrocarbon group is a monovalent aliphatic hydrocarbon group, it may be branched or unbranched, and part or all of the branched chain may be substituted with a halogen atom. Moreover, this hydrocarbon group may have an oxygen atom and / or a sulfur atom in its chain. Furthermore, when the monovalent hydrocarbon group has an aromatic hydrocarbon group, this aromatic hydrocarbon group may or may not have a substituent. However, the monovalent hydrocarbon group is obtained by dissolving the compound represented by the general formula (3) (hereinafter also referred to as “compound (3)”) in a solvent, Therefore, it is preferably a hydrocarbon group that makes the compound (3) easily soluble in a solvent, such as an aralkyl group typified by a benzyl group. Moreover, when the carbon number of the monovalent hydrocarbon group is 21 or more, it tends to be difficult to obtain raw materials. The monovalent hydrocarbon group represented by R ⁵ is preferably an alkyl group having 4 to 18 carbon atoms, more preferably an alkyl group having 4 to 14 carbon atoms, from the viewpoint of more effectively and reliably achieving the effects of the present invention. More preferably it is. R ⁵ is preferably a linear alkyl group from the viewpoint of gelling ability and handling properties.

上記一般式（３）において、Ｘ³は化合物（３）をリチウムイオン二次電池に用いた際に、長期にわたって安定である点とゲル化能とから選択すると好ましい。Ｘ³が上記式（３ａ）で表される基である場合、そのゲル化剤を含む組成物は、非常に安定性が高いゲルとなる傾向にある。また、Ｘ³が上記式（３ｅ）で表される基である場合、そのゲル化剤を含む組成物は、ゲル−ゾルの転移を温度調整だけではなく、光照射によっても誘起できる点で用途拡大に繋がる。 In the general formula (3), X ³ represents the following formulas (3a), (3b), (3c), (3d), (3e), (3f) and (3g) (hereinafter, (3a) to (3g) Or a divalent group in which two or more of the groups represented by the following formulas (3a) to (3g) are bonded to each other. Show. Among these, from the viewpoint of gelling ability, charge / discharge characteristics of the battery, and long-term stability, any divalent selected from the group consisting of groups represented by the following formulas (3a), (3e) and (3g) The group is preferably.

In the above general formula (3), X ³ is preferably selected from the point of being stable over a long period of time and the gelling ability when the compound (3) is used in a lithium ion secondary battery. When X ³ is a group represented by the above formula (3a), the composition containing the gelling agent tends to be a very stable gel. When X ³ is a group represented by the above formula (3e), the composition containing the gelling agent can be used in that the gel-sol transition can be induced not only by temperature adjustment but also by light irradiation. It leads to expansion.

In the general formula (3), Cm represents a monovalent group (coumarin moiety) represented by the following general formula (3z). In the following formula (3z), a plurality of R ^a are each independently a hydrogen atom. Represents an alkyl group, an alkoxy group or a halogen atom. When R ^a is an alkyl group, the carbon number is preferably 1 to 6, and when it is an alkoxy group, the carbon number is preferably 1 to 8.

  A low molecular gelling agent is used individually by 1 type or in combination of 2 or more types.

  The low molecular weight gelling agent according to this embodiment may be synthesized by a conventional method, or a commercially available product may be obtained. Among these gelling agents, those having a perfluoroalkyl group include, for example, International Publication No. 2007/083843, Japanese Patent Application Laid-Open No. 2007-191626, Japanese Patent Application Laid-Open No. 2007-191627, and Japanese Patent Application Laid-Open No. 2007-191661. It can manufacture with reference to the method of gazette and international publication 2009/78268.

The low molecular gelling agent having a perfluoroalkyl group used in the present embodiment can be synthesized, for example, by the following scheme. First, a thiol compound represented by the following general formula (11a) is sulfided with a compound represented by the following general formula (11b) in the presence of a base such as triethylamine in a solvent such as dry THF. The compound represented by (11c) is obtained.
HS-Ar-OH (11a)
C _m F _{2m + 1} C _p H _2p X ¹ (11b)
_{C m F 2m + 1 C p} H 2p -S-Ar-OH (11c)

Next, the compound represented by the general formula (11c) is etherified with a compound represented by the following general formula (11d) in the presence of an alkali metal compound such as K ₂ CO _{3 in} a solvent such as 3-pentanone. To obtain a compound represented by the following general formula (11e).
R ¹ X ² (11d)
_{C m F 2m + 1 C p} H 2p -S-Ar-O-R 1 (11e)

Then, the perfluoro compound represented by the following general formula (11j) is obtained by oxidizing the compound represented by the general formula (11e) with an oxidizing agent such as hydrogen peroxide in the presence of a catalyst such as acetic acid. Is obtained.
_{C m F 2m + 1 C p} H 2p -SO 2 -Ar-O-R 1 (11j)
Here, as long as in the production scheme of the perfluoro compound represented by the general formula (11j), Ar represents a substituted or unsubstituted divalent aromatic group having 8 to 30 nuclear atoms, and R ¹ is saturated or Represents an unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms, m represents a natural number of 2 to 16, p represents an integer of 0 to 6, and X ¹ represents a halogen atom such as an iodine atom, for example. X ² represents a halogen atom such as a bromine atom.

  As such a synthesis method, for example, the synthesis method described in International Publication No. 2009/78268 can be referred to.

Further, when Ar is a group in which a plurality of aromatic rings such as a biphenylene group or a terphenylene group are bonded by a single bond, a perfluoro compound represented by the above general formula (11j) is obtained by the following synthesis method, for example. Can do. First, a thiol compound represented by the following general formula (11f) is sulfided with a compound represented by the above general formula (11b) in the presence of a base such as triethylamine in a solvent such as dry THF. A compound represented by (11 g) is obtained. Here, in the formulas (11f) and (11g), m and p are as defined in the formula (11j), X ³ represents a halogen atom such as a bromine atom, and Ar ² represents the above formula (11j). ) Represents a part of the divalent aromatic hydrocarbon group constituting Ar.
^{HS-Ar 2 -X 3 (11f} )
_{C m F 2m + 1 C p} H 2p -S-Ar 2 -X 3 (11g)

Next, the following compound (11h) is obtained by oxidizing the compound represented by the general formula (11g) with an oxidizing agent such as hydrogen peroxide in the presence of a catalyst such as acetic acid. Here, in the formula (11h), Ar ² , X ³ , m and p are as defined in the formula (11g).
_{C m F 2m + 1 C p} H 2p -SO 2 -Ar 2 -X 3 (11h)

Then, from the compound represented by the above general formula (11h) and the compound represented by the following general formula (11i), in the presence of a palladium catalyst in a basic aqueous solution such as K ₂ CO ₃ , Suzuki-Miyaura coupling To obtain the perfluoro compound represented by the general formula (11j). Here, in the formula (11i), R ¹ has the same meaning as in the formula (11j), Ar ³ is Ar ² a divalent aromatic hydrocarbon group constituting Ar in the formula (11j) A part different from is shown, and Ar ² and Ar ³ bonded by a single bond is Ar.
R ¹ —O—Ar ³ —B (OH) ₂ (11i)

Moreover, the gelling agent which has the perfluoroalkyl group used for this embodiment is compoundable with the following scheme, for example. That is, from the compound represented by the following general formula (Ia) and the compound represented by the following general formula (IIa), dehydration condensation such as Mitsunobu reaction is a kind of gelling agent having a perfluoroalkyl group. A compound represented by the general formula (IIIa) can be synthesized. Here, in the formula, Y ¹ and Y ² are each independently a sulfur atom or an oxygen atom.
^{Rf 1 -R 1 -Y 1 -Z-} Y 2 H (Ia)
Rf ² R ² OH (IIa)
^{Rf 1 -R 1 -Y 1 -Z-} Y 2 -R 2 -Rf 2 (IIIa)

Further, in the compound represented by the above general formula (IIIa), when Y ¹ and / or Y ² is a sulfur atom, the sulfur atom is further sulfonylated or sulfoxidized to have a perfluoroalkyl group. A compound represented by the following general formula (IVa), which is another kind of gelling agent, can be synthesized. Here, at least one of Y ³ and Y ⁴ is an SO group or SO ₂ group, and when one of Y ³ and Y ⁴ is an SO group or SO ₂ group, the other is a sulfur atom or an oxygen atom.
^{Rf 1 -R 1 -Y 3 -Z-} Y 4 -R 2 -Rf 2 (IVa)

The compound represented by the general formula (Ia) is, for example, a perfluoroalkane halide (thiol group or a hydrogen atom of a hydroxyl group) of a compound represented by the following formula (Va) under alkaline conditions ( For example, it can be synthesized by substitution with a perfluoroalkyl group of iodide.
HY ¹ -ZY ² H (Va)
The compound represented by the above formula (IIa) can be synthesized by further reducing the halide of alkanol obtained by the addition reaction of perfluoroalkane halide (for example, iodide) to alkenol.

Here, as long as in the production scheme of the perfluoro compound (gelator) represented by the above general formula (IIIa) or (IVa), Rf ¹ and Rf ² are each independently of 2 to 18 carbon atoms in the main chain. A substituted or unsubstituted perfluoroalkyl group, R ¹ and R ² each independently represents a single bond or a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms in the main chain; A substituted or unsubstituted divalent aromatic hydrocarbon group or alicyclic hydrocarbon group having 5 to 30 nuclear atoms is shown.

  However, the synthesis method of the gelling agent having a perfluoroalkyl group used in the present embodiment is not limited to the above method.

  In addition, the compound (3) according to this embodiment is a coumarin-type gelling agent, and for example, the compound described in the liquid crystal discussion conference proceedings collection p44 (2007) can be used as the compound (3).

The compound (3) having an azo group, that is, the compound (3) in which X ³ is represented by the above formula (3e) can be synthesized, for example, by the following reaction pathway.

Examples of the compound (3) having an azo group synthesized in this way include a compound represented by the following formula (3I) (hereinafter also referred to as “compound (3I)”) and the following formula (3II). And a compound represented by the following (hereinafter also referred to as “compound (3II)”).

ナスフラスコに濃硝酸及び濃硫酸の混合溶液を加える。当該ナスフラスコを氷浴で冷却しながら、クマリンを、混合溶液の温度が２０℃を超えないように徐々に加える。クマリンを全量加え終えたら氷浴を外し、室温で１時間攪拌して反応させる。当該反応液を水中に注ぎ、析出した固体を濾取する。濾取した固体を、トルエンで再結晶を行い、淡黄色の固体の化合物（ａ）を得る。 Hereinafter, a method for synthesizing the compounds (3I) and (3II) will be described in detail.
[Method for Synthesizing Compound (3I)]
(Step 1: Synthesis of Compound (a))

Add a mixed solution of concentrated nitric acid and concentrated sulfuric acid to the eggplant flask. While cooling the eggplant flask in an ice bath, coumarin is gradually added so that the temperature of the mixed solution does not exceed 20 ° C. When all the coumarin has been added, remove the ice bath and stir at room temperature for 1 hour to react. The reaction solution is poured into water, and the precipitated solid is collected by filtration. The solid collected by filtration is recrystallized from toluene to obtain a light yellow solid compound (a).

(Step 2: Synthesis of Compound (b))

  In an eggplant flask, the compound (a) is dissolved in a mixed solution of ethanol and toluene, and a hydrogenation reaction is performed in the presence of Pd / C. After the hydrogenation reaction, Pd / C is collected by filtration, and the filtrate is concentrated by an evaporator. The precipitated solid is recrystallized from toluene to obtain a yellow solid compound (b).

(Step 3: Synthesis of Compound (c))

In an eggplant flask, a 12N aqueous hydrochloric acid solution is prepared under ice cooling at 5 ° C. Compound (b) and sodium nitrite (NaNO ₂ ) are added to the aqueous solution and stirred for 20 minutes. Further, a mixed solution of phenol, sodium hydroxide and water is added and stirred. The precipitated solid is recrystallized from toluene to obtain compound (c).
(Step 4: Synthesis of Compound (3I))

  In an eggplant flask, compound (c) is dissolved in 3-pentanone. 1-Bromooctane and potassium carbonate are added to the obtained solution and refluxed for 15 hours. The obtained solid is recrystallized from toluene and purified by column chromatography to obtain compound (3I). In the column chromatography, silica gel is used as a filler and chloroform is used as a developing solvent.

[Method for Synthesizing Compound (3II)]

  In an eggplant flask, compound (c) is dissolved in 3-pentanone. 1-Bromohexane and potassium carbonate are added to the obtained solution and refluxed for 15 hours. The obtained solid is recrystallized from toluene and purified by column chromatography to obtain compound (3II). In the column chromatography, silica gel is used as a filler and chloroform is used as a developing solvent.

  However, the manufacturing method of a compound (3) is not limited to the said method.

<Polymer binder>
As the polymer binder (polymer binder) of the present embodiment, various materials can be used as long as they are sticky polymers. Various polymers are known as the polymer binder, and examples thereof include solution polymers, slurry polymers, polycondensates, and emulsion polymers.

  As the polymer binder of the present embodiment, for example, a polymer having a polyether moiety (polymer), a polymer having a poly (meth) acrylic acid moiety, a polymer having a poly (meth) acrylic acid ester moiety, Examples include a polymer having a polyacrylonitrile moiety, a polymer having a polyurethane moiety, a polymer having a polyamide moiety, a halogen-containing polymer (for example, a polymer having a polyvinylidene fluoride moiety), and a silicon-containing polymer.

  The polymer binder may be a mixture of a plurality of polymers, a copolymer, a polymer, or a polymer in order to better develop performance such as charge / discharge performance and battery safety. It may be an alloy or a compound resin. Moreover, what has a bridge | crosslinking site | part may be sufficient and a natural polymer may be sufficient.

  The polymer binder in the present embodiment is preferably a polymer having at least one selected from the group consisting of halogen atoms and (meth) acryl groups from the viewpoint of handling and battery characteristics. The halogen atom of the polymer having a halogen atom is more preferably a fluorine atom. That is, the polymer having a halogen atom is more preferably a fluorine-containing polymer that is a polymer having a fluorine atom. These polymer binders may be in the form of a lump or powder, or in the form of particles or latex, and may be any solid, liquid (including solution) or slurry. Form may be sufficient.

  Examples of the fluorine-containing polymer include a fluororesin such as PTFE, a homopolymer of vinylidene fluoride (polyvinylidene fluoride: PVdF), and fluororubber. Copolymerization of two or more monomers among the monomers constituting them. It may be a coalescence, or may be a copolymer of at least one of the monomers constituting them and other monomers. Among these, PVdF or a copolymer of vinylidene fluoride and other monomers is preferably used. Examples of other monomers include hexafluoropropylene, trifluoropropylene, vinyl fluoride, trifluoroethylene, trifluorochloroethylene, and fluoroalkylvinyl ether.

  Examples of the polymer having a (meth) acrylic moiety include poly (meth) acrylic acid, poly (meth) acrylic ester and poly (meth) acrylonitrile, and a copolymer of two or more monomers among the monomers constituting them. It may be a polymer, or may be a copolymer of one or more of the monomers constituting them and other monomers. When the monomer is a (meth) acrylic acid ester, specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic. Examples include isopropyl acid, fluoromethyl (meth) acrylate, and fluoroethyl (meth) acrylate. Of these, copolymers of methyl (meth) acrylate and other monomers, polyacrylonitrile, and copolymers of acrylonitrile and other monomers are preferably used. Examples of other monomers include styrene, ethylene, propylene, butadiene, and maleic anhydride.

  The polymer binder is used singly or in combination of two or more, and may be synthesized by a conventional method or obtained as a commercial product.

<Solvent>
In the production method of the present embodiment, when a low molecular gelling agent is present on the surface of the positive electrode, the negative electrode, or the separator, a solution as a composition in which these members include a low molecular gelling agent and a polymer binder. Alternatively, a low molecular weight gelling agent may be present on the surface by being immersed in the dispersion. In this case, the dispersion may be in any form of liquid, slurry, or gel. The composition containing the low molecular gelling agent and the polymer binder preferably contains a nonaqueous solvent, and is prepared by dissolving or dispersing the low molecular weight gelling agent and the polymer binder in the nonaqueous solvent. can do.

  A variety of non-aqueous solvents can be used. Specific examples thereof include, for example, alcohols such as methanol, ethanol, isopropanol, butanol and octanol; methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, γ-butyrolactone, γ-valerolactone, δ-valero Acid esters such as lactone and ε-caprolactone; ketones such as dimethyl ketone, diethyl ketone, methyl ethyl ketone, 3-pentanone and acetone; pentane, hexane, octane, cyclohexane, benzene, toluene, xylene, fluorobenzene and hexafluorobenzene Hydrocarbons such as dimethyl ether, diethyl ether, 1,2-dimethoxyethane, 1,4-dioxane, crown ethers, glymes, tetrahydrofuran and fluorine-containing ethers. Ethers such as N, N-dimethylacetamide and N, N-dimethylformamide; amines such as ethylenediamine and pyridine; propylene carbonate, ethylene carbonate, vinylene carbonate, fluoroethylene carbonate, 1,2-butylene carbonate, Trans-2,3-butylene carbonate, cis-2,3-butylene carbonate, 1,2-pentylene carbonate, trans-2,3-pentylene carbonate, cis-2,3-pentylene carbonate, vinylethylene carbonate, Trifluoromethyl ethylene carbonate, 4,5-difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl iso Carbonates such as propyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate and methyl trifluoroethyl carbonate; nitriles such as acetonitrile, propionitrile, adiponitrile, succinonitrile, malononitrile and methoxyacetonitrile; N -Lactams such as methyl pyrrolidone (NMP); sulfones such as sulfolane and 3-methyl sulfolane, ethyl methyl sulfone and dimethyl sulfone; sulfonic acid esters such as ethylene sulfite and butylene sulfite; sulfoxides such as dimethyl sulfoxide; Industrial oils such as silicone oil and petroleum; and edible oils. These are used singly or in combination of two or more.

An ionic liquid can also be used as the non-aqueous solvent. An ionic liquid is a liquid composed of ions obtained by combining an organic cation and an anion.
Examples of the organic cation include imidazolium ions such as dialkylimidazolium cation and trialkylimidazolium cation, tetraalkylammonium ion, alkylpyridinium ion, dialkylpyrrolidinium ion, and dialkylpiperidinium ion.

Examples of the anion serving as a counter for these organic cations include PF ₆ anion, PF ₃ (C ₂ F ₅ ) ₃ anion, PF ₃ (CF ₃ ) ₃ anion, BF ₄ anion, and BF ₂ (CF ₃ ) ₂ anion. BF ₃ (CF ₃ ) anion, bisoxalatoborate anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutanesulfonyl) anion, bis (fluorosulfonyl) imide anion, bis (trifluoromethanesulfonyl) imide anion, bis (Pentafluoroethanesulfonyl) imide anion, dicyanoamine anion, halide anion can be used.

  These solvents are used alone or in combination of two or more.

  The content of the low-molecular gelling agent in the composition containing the low-molecular gelling agent and the polymer binder used in the present embodiment is arbitrary. When the composition contains a non-aqueous solvent, the content ratio to the non-aqueous solvent (low molecular gelling agent / non-aqueous solvent) is preferably 0.01 to 50 on a mass basis, and preferably 0.1 to 20 More preferably.

The content of the polymer binder in the composition containing the low-molecular gelling agent and the polymer binder is arbitrary, but the content ratio of the polymer binder to the nonaqueous solvent (polymer binder) / Non-aqueous solvent) is preferably 0.001 to 200 and more preferably 0.01 to 100 on a mass basis.
The content of either the low-molecular gelling agent or the polymer binder, preferably the content of both being within the above range, can easily improve the adhesion of the electrode and separator, and battery characteristics. Will be even better.

  The composition containing the low molecular gelling agent and the polymer binder according to the present embodiment may further contain a lithium salt. Thereby, the dispersibility of the lithium salt in the lithium ion secondary battery becomes better. Since the lithium salt and its concentration may be the same as those in the electrolyte solution described later, detailed description thereof is omitted here.

<Positive electrode>
In the lithium ion secondary battery of this embodiment, the positive electrode contains one or more materials selected from the group consisting of materials capable of inserting and extracting lithium ions as the positive electrode active material. Examples of such materials include composite oxides represented by the following general formulas (6a) and (6b), metal chalcogenides and metal oxides having a tunnel structure and a layered structure, and olivine-type phosphate compounds.
Li _x MO ₂ (6a)
Li _y M ₂ O ₄ (6b)
Here, in the formula, M represents one or more metals selected from transition metals, x represents a number from 0 to 1, and y represents a number from 0 to 2.

More specifically, for example, lithium cobalt oxide typified by LiCoO ₂ ; lithium manganese oxide typified by LiMnO ₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O ₄ ; lithium nickel typified by LiNiO ₂ Oxide; represented by Li _z MO ₂ (M represents two or more elements selected from the group consisting of Ni, Mn, Co, Al, and Mg, and z represents a number greater than 0.9 and less than 1.2). And lithium-containing composite metal oxide; and iron phosphate olivine represented by LiFePO ₄ . Further, as the positive electrode active material, for example, a metal other than lithium represented by S, MnO ₂ , FeO ₂ , FeS ₂ , V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , TiS ₂ , MoS ₂ and NbSe ₂ is used. An oxide etc. are also illustrated. Furthermore, conductive polymers represented by polyaniline, polythiophene, polyacetylene, and polypyrrole are also exemplified as the positive electrode active material.
In the lithium ion secondary battery of this embodiment, the positive electrode preferably includes a lithium-containing compound as a positive electrode active material.

Further, it is preferable to use a lithium-containing compound as the positive electrode active material because a high voltage and a high energy density tend to be obtained. As such a lithium-containing compound, any compound containing lithium may be used. For example, a composite oxide containing lithium and a transition metal element, a phosphate compound containing lithium and a transition metal element, and lithium and a transition metal element (For example, Li _{t Mu} SiO ₄ , where M is as defined in the above formula (6a), t is a number from 0 to 1, and u is a number from 0 to 2). . From the viewpoint of obtaining a higher voltage, lithium, cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), vanadium ( V) and composite oxides containing at least one transition metal element selected from the group consisting of titanium (Ti) and phosphate compounds are preferred.

More specifically, the lithium-containing compound is preferably a metal oxide having lithium, a metal chalcogenide having lithium, and a metal phosphate compound having lithium. For example, the lithium-containing compounds are represented by the following general formulas (7a) and (7b), respectively. The compound which is made is mentioned.
^{_{Li v M I O 2 (7a}} )
Li _w M ^II PO ₄ (7b)
Here, in the formula, M ^I and M ^II each represent one or more transition metal elements, and the values of v and w vary depending on the charge / discharge state of the battery, but usually v is 0.05 to 1.10, w Indicates a number from 0.05 to 1.10.

  The compound represented by the general formula (7a) generally has a layered structure, and the compound represented by the general formula (7b) generally has an olivine structure. In these compounds, for the purpose of stabilizing the structure, a part of the transition metal element is substituted with Al, Mg, other transition metal elements or included in the crystal grain boundary, a part of the oxygen atom And those substituted with a fluorine atom or the like. Furthermore, what coat | covered the other positive electrode active material to at least one part of the positive electrode active material surface is mentioned.

  A positive electrode active material is used individually by 1 type or in combination of 2 or more types.

  The number average particle diameter (primary particle diameter) of the positive electrode active material is preferably 0.05 μm to 100 μm, more preferably 1 μm to 10 μm. The number average particle size of the positive electrode active material can be measured by a wet particle size measuring device (for example, a laser diffraction / scattering particle size distribution meter, a dynamic light scattering particle size distribution meter). Alternatively, 100 particles observed with a transmission electron microscope are randomly extracted and analyzed with image analysis software (for example, image analysis software manufactured by Asahi Kasei Engineering Co., Ltd., trade name “A Image-kun”). It can also be obtained by calculating an average. In this case, when the number average particle diameter differs between measurement methods for the same sample, a calibration curve created for the standard sample may be used.

The positive electrode is obtained, for example, as follows. That is, first, a positive electrode mixture-containing paste is prepared by dispersing, in a solvent, a positive electrode mixture obtained by adding a conductive additive, a binder, or the like to the positive electrode active material as necessary. Next, this positive electrode mixture-containing paste is applied to a positive electrode current collector and dried to form a positive electrode mixture layer, which is pressurized as necessary to adjust the thickness, thereby producing a positive electrode.
Here, the solid content concentration in the positive electrode mixture-containing paste is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.
The positive electrode current collector is made of, for example, a metal foil such as an aluminum foil or a stainless steel foil.

  One of the members in the present embodiment is present on the positive electrode and at least a part of its surface from the viewpoint of improving the adhesion between the separator and the positive electrode or the adhesion between the negative electrode and the positive electrode. A part containing a low molecular gelling agent. In this part, the low molecular gelling agent may be directly attached to the surface of the positive electrode, may be attached via a polymer binder, or they may be mixed. When the low molecular gelling agent attached in such a manner is attached to the surface having an area of 0.01% to 40% with respect to the entire surface area of the positive electrode, both battery characteristics and adhesiveness are achieved at a high level. This is preferable. The presence state of the low-molecular gelling agent may be a network in which a large number of gelling agent molecules are associated, or may be an aggregate of a small number of gelling agent molecules or a dispersed state for each single molecule. Moreover, the high molecular binder and the low molecular gelling agent may be fused together.

The method for allowing the low molecular gelling agent to be present on the surface of the positive electrode is not particularly limited, but it is preferable that the composition containing the low molecular gelling agent and the polymer binder is brought into direct contact with at least a part of the surface of the positive electrode. . More specifically, as a method for making it exist, for example, a method of cast-coating a composition containing a low-molecular gelling agent and a polymer binder on the positive electrode, coating using a bar, a blade, a roller, or the like And a flow coating method.
In addition, a positive electrode active material and / or a positive electrode obtained by further adding a positive electrode active material and / or a positive electrode mixture to a composition containing a low molecular gelling agent and a polymer binder is applied to the positive electrode. Application of the mixture and the presence of the low-molecular gelling agent can be carried out simultaneously. Furthermore, a method of immersing the positive electrode in a composition comprising a low molecular gelling agent and a polymer binder, or a composition comprising a low molecular gelling agent, a polymer binder and a positive electrode active material or a positive electrode mixture Also mentioned. According to these methods, it is possible to make the low molecular gelling agent exist not only on the surface of the positive electrode but also inside the positive electrode. Alternatively, by mixing a low-molecular gelling agent and a polymer binder in the electrolyte of the lithium ion secondary battery, as a result, in the lithium ion secondary battery, the gelling agent should be present on the positive electrode surface. You can also. In particular, the positive electrode is impregnated with the low-molecular gelling agent and the high-molecular binder by the method of immersing the positive electrode in the above composition or an electrolytic solution in which the low-molecular gelling agent and the high-molecular binder are mixed. Therefore, it is easier to make the low molecular gelling agent present inside the positive electrode. The presence of a low-molecular gelling agent inside the positive electrode is advantageous from the viewpoint that the adhesion and affinity between the low-molecular gelling agent and the positive electrode become stronger. Since the low molecular gelling agent has already been described, the detailed description thereof is omitted here.

<Negative electrode>
In the lithium ion secondary battery of the present embodiment, the negative electrode contains at least one material selected from the group consisting of a material capable of inserting and extracting lithium ions as a negative electrode active material and metallic lithium. In the lithium ion secondary battery of this embodiment, the negative electrode is one type selected from the group consisting of metallic lithium, a carbon material, a material containing an element capable of forming an alloy with lithium, and a lithium-containing compound as a negative electrode active material. It is preferable to contain the above materials. Examples of such materials include lithium metal, hard carbon, soft carbon, artificial graphite, natural graphite, graphite, pyrolytic carbon, coke, glassy carbon, organic polymer compound fired body, mesocarbon microbeads. Carbon materials represented by carbon fiber, activated carbon, graphite, carbon colloid, and carbon black. Among these, examples of the coke include pitch coke, needle coke, and petroleum coke. Further, the fired body of the organic polymer compound is obtained by firing and polymerizing a polymer material such as a phenol resin or a furan resin at an appropriate temperature. In the present embodiment, a battery employing metallic lithium as the negative electrode active material is also included in the lithium ion secondary battery.

  Further, examples of the material capable of inserting and extracting lithium ions include a material containing an element capable of forming an alloy with lithium. This material may be a single metal or a semi-metal, an alloy or a compound, and may have at least a part of one or more of these phases. Good.

  In the present specification, the “alloy” includes an alloy having one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. In addition, the alloy may have a nonmetallic element as long as the alloy has metallic properties as a whole. In the alloy structure, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of these coexist.

  Examples of such metal elements and metalloid elements include titanium (Ti), tin (Sn), lead (Pb), aluminum, indium (In), silicon (Si), zinc (Zn), and antimony (Sb). Bismuth (Bi), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr) and yttrium (Y).

  Among these, metal elements and metalloid elements of Group 4 or 14 in the long-period periodic table are preferable, and titanium, silicon, and tin are particularly preferable.

  As an alloy of tin, for example, as a second constituent element other than tin, silicon, magnesium (Mg), nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti), germanium, bismuth, Examples thereof include those having one or more elements selected from the group consisting of antimony and chromium (Cr).

  Examples of the silicon alloy include, as the second constituent element other than silicon, tin, magnesium, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium. Those having one or more elements selected from the above are listed.

Examples of the titanium compound, the tin compound, and the silicon compound include those having oxygen (O) or carbon (C), and in addition to titanium, tin, or silicon, the second constituent element described above is included. It may be.
Moreover, a lithium containing compound is also mentioned as a material which can occlude and release lithium ions. As the lithium-containing compound, the same compounds as those exemplified as the positive electrode material can be used.

  A negative electrode active material is used individually by 1 type or in combination of 2 or more types.

  The number average particle diameter (primary particle diameter) of the negative electrode active material is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm. The number average particle size of the negative electrode active material is measured in the same manner as the number average particle size of the positive electrode active material.

A negative electrode is obtained as follows, for example. That is, first, a negative electrode mixture-containing paste is prepared by dispersing, in a solvent, a negative electrode mixture prepared by adding a conductive additive, a binder, or the like to the negative electrode active material as necessary. Next, the negative electrode mixture-containing paste is applied to a negative electrode current collector and dried to form a negative electrode mixture layer, which is pressurized as necessary to adjust the thickness, thereby producing a negative electrode.
Here, the solid content concentration in the negative electrode mixture-containing paste is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.
The negative electrode current collector is made of, for example, a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

  Another one of the components in the present embodiment is that on the negative electrode and at least a part of the surface thereof, from the viewpoint of improving the adhesion between the separator and the negative electrode or the adhesion between the positive electrode and the negative electrode. It is a part containing the low molecular gelling agent which exists. In this component, the low molecular gelling agent may be directly attached to the surface of the negative electrode, may be attached via a polymer binder, or they may be mixed. When the low molecular gelling agent adhered in such a manner adheres to the surface having an area of 0.01% or more and 40% or less with respect to the entire surface area of the negative electrode, both battery characteristics and adhesiveness are achieved at a high level. This is preferable. The presence state of the low-molecular gelling agent may be a network in which a large number of gelling agent molecules are associated, or may be an aggregate of a small number of gelling agent molecules or a dispersed state for each single molecule. Moreover, the high molecular binder and the low molecular gelling agent may be fused together.

The method for allowing the low molecular gelling agent to be present on the negative electrode surface is not particularly limited, but it is preferable that the composition containing the low molecular gelling agent and the polymer binder is brought into direct contact with at least a part of the surface of the negative electrode. . More specifically, as a method of making it exist, for example, a method of casting a composition containing a low molecular gelling agent and a polymer binder on the negative electrode, coating using a bar, a blade, a roller or the like And a flow coating method.
In addition, a negative electrode active material and / or a negative electrode material, which further contains a negative electrode active material and / or a negative electrode mixture in a composition containing a low molecular gelling agent and a polymer binder, is applied to the negative electrode. Application of the mixture and the presence of the low-molecular gelling agent can be carried out simultaneously. Furthermore, the negative electrode is immersed in a composition containing a low molecular gelling agent and a polymer binder, or a composition containing a low molecular gelling agent, a polymer binder and a negative electrode active material or a negative electrode mixture. A method is also mentioned. According to these methods, it is possible to make the low molecular gelling agent exist not only on the surface of the negative electrode but also inside the negative electrode. Alternatively, a low molecular gelling agent and a polymer binder are mixed in the electrolyte of the lithium ion secondary battery, and as a result, in the lithium ion secondary battery, the gelling agent is present on the negative electrode surface. You can also. In particular, a composition containing a low molecular weight gelling agent and a high molecular weight binder is obtained by immersing the negative electrode in the above composition or an electrolytic solution in which a low molecular weight gelling agent and a high molecular weight binder are mixed. Since the negative electrode can be impregnated, it is easier to make the low molecular gelling agent present inside the negative electrode. The presence of the low molecular gelling agent also in the negative electrode is advantageous from the viewpoint that the adhesion and affinity between the low molecular gelling agent and the negative electrode become stronger. Since the low molecular gelling agent has already been described, the detailed description thereof is omitted here.

  In the process of manufacturing a lithium ion secondary battery, when a low molecular gelling agent is present on both surfaces of the positive electrode and the negative electrode, the low molecular gelling agent and the polymer binder are the same as each other. It may or may not be different.

  In the production of the positive electrode and the negative electrode and the above-described components each containing them, examples of the conductive aid used as necessary include carbon black typified by graphite, acetylene black and ketjen black, and carbon fibers. The number average particle size (primary particle size) of the conductive assistant is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm, and is measured in the same manner as the number average particle size of the positive electrode active material. Examples of the binder include polyvinylidene fluoride (PVDF), a copolymer containing polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyacrylic acid, polyacrylic acid ester, and a copolymer containing polyacrylic acid ester. A polymer, a styrene butadiene rubber, a fluoro rubber, and a polymer having a cellulose moiety are exemplified.

<Separator>
In the lithium ion secondary battery of this embodiment, a separator may be provided between the positive electrode and the negative electrode from the viewpoint of providing safety such as prevention of short circuit between the positive and negative electrodes and shutdown. The separator is preferably an insulating thin film having high ion permeability and excellent mechanical strength.
Examples of the material of the separator used in this embodiment include ceramic, glass, resin, and cellulose. The resin may be a synthetic resin or a natural resin (natural polymer), and may be an organic resin or an inorganic resin, but from the viewpoint of excellent performance as a separator. An organic resin is preferable. Examples of the organic resin include polyolefin, polyester, polyamide, and heat resistant resins such as liquid crystal polyester and aramid. The material of the separator is preferably ceramic and glass from the viewpoint of high heat resistance, and polyester, polyamide, liquid crystal polyester, aramid, and cellulose are preferable from the viewpoint of handling properties and heat resistance. The separator material is preferably polyolefin from the viewpoint of cost and processability. Among these materials, when a resin is employed, a resin that is a homopolymer may be used, a copolymer resin may be used, or a mixture of a plurality of types of resins and an alloy may be used. Further, the separator may be a laminated body in which films made of a plurality of materials are laminated. When the separator is a laminate, the material of each layer may be the same or different. In the case of manufacturing a separator of a laminated body, it may be manufactured by sequentially stacking a certain layer on another layer, that is, by sequentially multilayering, and a plurality of separate films may be bonded together. Thus, a laminate may be produced.

The form of the separator used in this embodiment is, for example, a synthetic resin microporous film produced by forming a synthetic resin, a fiber spun from a synthetic resin or a natural polymer, a woven fabric processed from glass fiber or ceramic fiber, Nonwoven fabrics, knitted fabrics, papermaking, and films prepared by arranging fine particles of synthetic resin and glass can be mentioned.
The separator may be obtained by stacking a plurality of films produced by a plurality of production methods, or may be obtained by sequentially multilayering a plurality of production methods.
The separator according to the present embodiment is made of a component other than the above, for example, an organic filler, an inorganic filler, an organic particle, or an inorganic particle on the surface and / or inside of the separator from the viewpoints of film reinforcement, charge / discharge assist, heat resistance improvement, and the like. May be included.

  Another one of the components in the present embodiment is the separator between the positive electrode and the negative electrode through the separator, between the separator and the positive electrode, or from the viewpoint of improving the adhesion between the separator and the negative electrode. And a low molecular gelling agent present on at least a part of the surface thereof. In this part, the low molecular gelling agent may be directly attached to the surface of the separator, may be attached via a polymer binder, or they may be mixed, but at least the polymer binder It is preferable to adhere via. It is preferable that the low-molecular gelling agent so attached is attached to the surface having an area of 0.01% or more and 99.9% or less with respect to the entire surface area of the separator because high adhesiveness can be realized. The presence state of the low-molecular gelling agent may be a network in which a large number of gelling agent molecules are associated, or may be an aggregate of a small number of gelling agent molecules or a dispersed state for each single molecule. Moreover, the high molecular binder and the low molecular gelling agent may be fused together. The composition may be a solution or a dispersion, and the dispersion may be liquid, gel, or slurry.

  The method for allowing the low-molecular gelling agent to be present on the separator surface is not particularly limited, but it is preferable that the composition containing the low-molecular gelling agent and the polymer binder is directly brought into contact with the surface of at least a part of the separator. . More specifically, examples of the existing method include a method of cast coating on a separator, a method of coating using a bar, a blade and a roller, a method of flow coating, a low molecular gelling agent and a polymer. The method of immersing a separator in the composition containing a binder is mentioned. According to these methods, it is possible to make the low-molecular gelling agent exist not only on the surface of the separator but also inside the separator. In particular, since the separator is impregnated with the composition containing the low-molecular gelling agent by the method of immersing the separator, it is easier to make the low-molecular gelling agent present inside the separator. The presence of a low-molecular gelling agent inside the separator (including pores) is advantageous from the viewpoint of improving the non-uniformity of the pore size and pore size distribution of the separator and contributing to stabilization of charge and discharge. . Further, the more low-molecular gelling agent is present in the separator (including the pores), the higher adhesiveness can be realized, which is preferable. On the other hand, the smaller the amount of the low-molecular gelling agent in the separator (including the pores), the more preferable from the viewpoint of easily maintaining the functions inherent to the separator such as charge / discharge capacity and shutdown characteristics.

  The amount of the low-molecular gelling agent and the high-molecular binder present in the separator can be determined by, for example, observing the separator in which the low-molecular gelling agent and the high-molecular binder are present with an electron microscope. It can be obtained by image processing.

  In the process of manufacturing a lithium ion secondary battery, when a low molecular gelling agent is present on any two or more surfaces of the positive electrode, the negative electrode, and the separator, the low molecular gelling agent and the polymer binder The agents may be the same as or different from each other.

<Electrolyte>
The electrolytic solution used in this embodiment preferably contains (I) a nonaqueous solvent and (II) a lithium salt.
(I) Various non-aqueous solvents can be used. Specific examples thereof include an aprotic solvent. When used as an electrolyte solution for a lithium ion secondary battery, an aprotic polar solvent is preferable in order to increase the ionization degree of a lithium salt that is an electrolyte that contributes to the charge and discharge. Specific examples thereof include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, trans-2,3-butylene carbonate, cis-2,3-butylene carbonate, 1,2-pentylene carbonate, and trans-2,3. A cyclic carbonate represented by pentylene carbonate, cis-2,3-pentylene carbonate, vinylene carbonate, vinyl ethylene carbonate, trifluoromethyl ethylene carbonate, fluoroethylene carbonate and 4,5-difluoroethylene carbonate; γ-butyrolactone, Lactones represented by ε-caprolactone, δ-valerolactone and γ-valerolactone; cyclic sulfones represented by sulfolane and 3-methylsulfolane; propane sultone and butane sultone Cyclic sulfonic acid ester represented; Cyclic ether represented by tetrahydrofuran, crown ether and dioxane; methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, Chain carbonates typified by ethylpropyl carbonate and methyltrifluoroethyl carbonate; nitriles typified by acetonitrile, propionitrile, adiponitrile, malononitrile and succinonitrile; typified by dimethyl ether, dimethoxyethane, glyme and fluorine-containing ether Chain ether; chain carboxylic acid ester represented by methyl propionate; chain ether Examples thereof include a carbonate compound, N, N-dimethylformamide, N, N-dimethylacetamide and the like. These are used singly or in combination of two or more.

  (I) The non-aqueous solvent preferably contains one or more cyclic aprotic polar solvents in order to increase the ionization degree of the lithium salt. From the same viewpoint, (I) the nonaqueous solvent more preferably contains one or more cyclic carbonates typified by ethylene carbonate and propylene carbonate. The cyclic compound has a high dielectric constant, helps ionization of the lithium salt, and enhances the gelation ability.

(I) An ionic liquid can also be used as the non-aqueous solvent. An ionic liquid is a liquid composed of ions obtained by combining an organic cation and an anion.
Examples of the organic cation include imidazolium ions such as dialkylimidazolium cation and trialkylimidazolium cation, tetraalkylammonium ion, alkylpyridinium ion, dialkylpyrrolidinium ion, and dialkylpiperidinium ion.

Examples of the anion serving as a counter for these organic cations include PF ₆ anion, PF ₃ (C ₂ F ₅ ) ₃ anion, PF ₃ (CF ₃ ) ₃ anion, BF ₄ anion, and BF ₂ (CF ₃ ) ₂ anion. BF ₃ (CF ₃ ) anion, bisoxalatoborate anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutanesulfonyl) anion, bis (fluorosulfonyl) imide anion, bis (trifluoromethanesulfonyl) imide anion, bis (Pentafluoroethanesulfonyl) imide anion, dicyanoamine anion, halide anion can be used.

  These non-aqueous solvents are used alone or in combination of two or more.

Specific examples of the (II) lithium salt used as the electrolyte include, for example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiOSO ₂ C _k F _{2k + 1} [k is 1 to 8. Integer], LiN (SO ₂ C _k F _{2k + 1} ) ₂ [k is an integer of 1 to 8], LiPF _n (C _k F _{2k + 1} ) _6-n [n is an integer of 1 to 5, k is 1 ˜8], LiBF _n ((C _k F _{2k + 1} ) _4-n [n is an integer of 1 to 3, k is an integer of 1 to 8], LiB (C ₂ O ₄ ) ₂ Examples thereof include lithium bis (oxalate) borate, lithium difluoro (oxalate) borate represented by LiBF ₂ (C ₂ O ₄ ), and lithium trifluoro (oxalate) phosphate represented by LiPF ₃ (C ₂ O ₄ ).

Moreover, the lithium salt represented by the following general formula (a), (b), or (c) can also be used as an electrolyte.
LiC (SO ₂ R ¹¹ ) (SO ₂ R ¹² ) (SO ₂ R ¹³ ) (a)
LiN (SO ₂ OR ¹⁴ ) (SO ₂ OR ¹⁵ ) (b)
LiN (SO ₂ R ¹⁶ ) (SO ₂ OR ¹⁷ ) (c)
Here, in the formula, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ may be the same or different from each other, and are a C 1-8 perfluoroalkyl group. Indicates.

These electrolytes are used singly or in combination of two or more. Among these electrolytes, LiPF ₆ , LiBF ₄ and LiN (SO ₂ C _k F _{2k + 1} ) ₂ [k is an integer of 1 to 8] from the viewpoint of enhancing gelation ability in addition to battery characteristics and battery stability. Is preferred.

  The concentration of the electrolyte is arbitrary and is not particularly limited, but the electrolyte is preferably contained in the electrolytic solution at a concentration of 0.1 to 3 mol / liter, more preferably 0.5 to 2 mol / liter.

  The electrolytic solution used in the present embodiment preferably contains a low molecular gelling agent. When the electrolytic solution contains a low-molecular gelling agent, it is particularly excellent in satisfying battery safety and battery characteristics required for a lithium ion secondary battery, and therefore, it is preferably used in a lithium ion secondary battery. Further, the electrolytic solution may contain both a low molecular gelling agent and a polymer binder, and in that case, the electrolytic solution is a composition containing the low molecular gelling agent and the polymer binder. It may also serve as a role.

  The content of the low molecular weight gelling agent is arbitrary, but the content ratio of the low molecular weight gelling agent: nonaqueous solvent is 0.1: 99.9 to 10:90 on a mass basis as the content ratio with the nonaqueous solvent. And preferably 0.3: 99.7 to 5:95. When the content ratio of these components is within the above range, the lithium ion secondary battery using the electrolytic solution exhibits particularly high battery characteristics. Moreover, both gelling ability and handling property can be improved. In addition, as the content of the gelling agent in the electrolytic solution is larger, the electrolytic solution has a higher phase transition point and becomes a firm gel. As the content of the gelling agent is smaller, the viscosity of the electrolytic solution is lower and easier to handle. Since the low molecular gelling agent may be the same as described above, detailed description thereof is omitted here.

  The electrolyte solution containing a low-molecular gelling agent used in this embodiment is preferably a phase transition electrolyte solution in which sol-gel transition occurs due to reversible physical interaction. For example, a gel electrolyte solution that is a gel at a temperature equal to or lower than a predetermined temperature and is a sol at a temperature higher than the predetermined temperature is preferable. In the lithium ion secondary battery of the present embodiment, when the electrolytic solution is such a gel electrolyte solution, the handling properties such as liquid injection are excellent, and there is a tendency that safety such as liquid leakage reduction can be secured at a high level. . From such a viewpoint, when the physical change is a temperature change, the predetermined temperature, that is, the phase transition temperature between the gel and the sol is more preferably in the range of 50 to 150 ° C.

  The content of the polymer binder is arbitrary, but the content ratio of the polymer binder to the nonaqueous solvent is 0.5: 99.5 to 50:50 on a mass basis. And preferably 1:99 to 30:70. When the content ratio of these components is within the above range, higher battery characteristics and adhesiveness are exhibited. Since the polymer binder may be the same as described above, a detailed description thereof is omitted here.

  When the electrolyte further contains a low molecular gelling agent and a polymer binder, the mixing ratio of the non-aqueous solvent and the lithium salt that is the electrolyte, the low molecular gelling agent, and the polymer binder depends on the purpose. Can be selected. It is desirable that the electrolyte concentration, the low-molecular gelling agent, and the content of the polymer binder are all within the above-mentioned preferred range, and more preferred range. By producing an electrolytic solution with such a composition, battery characteristics and handleability can be further improved.

  The electrolyte solution in the present embodiment can contain other additives as necessary. Examples of the additive include a heat stabilizer, a flame retardant, a thermal runaway inhibitor, an overcharge suppression additive, a thickener, an emulsifier, a reinforcing agent, and an additive for forming an electrode protective film. These additives may be solid (bulk), powder, or liquid, and may be dissolved or not dissolved in the electrolytic solution.

  The content of the additive in the electrolytic solution is selected within a range that does not hinder the achievement of the object of the present invention and can achieve the purpose of using the additive. From the viewpoint of achieving both good battery characteristics and the effect of the additive, the content of the additive is 0.05 to 20 parts by mass with respect to 100 parts by mass of the total amount of the nonaqueous solvent and the electrolyte. Is preferable, and it is more preferable that it is 0.1 mass part-10 mass parts.

  The method for preparing the electrolytic solution used in the present embodiment is not particularly limited as long as the above components are mixed, and the order of mixing the electrolyte, the nonaqueous solvent, the low molecular gelling agent, and the polymer binder is not limited. Absent. For example, after preparing a preliminary electrolyte by mixing a predetermined amount of electrolyte and a non-aqueous solvent, the low-molecular gelling agent and the polymer binder are mixed in the preliminary electrolyte and used in this embodiment. A liquid can be obtained. Alternatively, it is possible to obtain an electrolytic solution used in the present embodiment by simultaneously mixing all the components in a predetermined amount. It is preferable to heat the electrolytic solution containing the low-molecular gelling agent once and cool it to room temperature in a state where each component in the mixture is uniform.

  The lithium ion secondary battery of the present embodiment is, for example, a lithium ion secondary battery that schematically shows a cross-sectional view in FIG. A lithium ion secondary battery 100 shown in FIG. 1 includes a separator 110, a positive electrode 120 and a negative electrode 130 that sandwich the separator 110 from both sides, and a positive electrode current collector 140 that sandwiches a laminate thereof (arranged outside the positive electrode). And a negative electrode current collector 150 (arranged outside the negative electrode), and a battery case 160 that is a battery exterior housing them. A laminate in which the positive electrode 120, the separator 110, and the negative electrode 130 are laminated is impregnated with the above-described electrolytic solution. As these members, those described above can be used, and those not described above can be the same as those provided in a conventional lithium ion secondary battery. Although not clearly shown in FIG. 1, a low molecular gelling agent exists between the positive electrode 120 and the separator 110 and / or between the negative electrode 130 and the separator 110, and the low molecular gelation is performed. The positive electrode 120 and the separator 110 and / or the negative electrode 130 and the separator 110 are bonded by the agent.

  Hereafter, each process in the manufacturing method of the lithium ion secondary battery of this embodiment is demonstrated in detail. The manufacturing method of this embodiment is not specifically limited except having the following steps, and may be the same as the manufacturing method of a conventional lithium ion secondary battery.

<Step (1) step of allowing a low-molecular gelling agent to exist>
In this step (1), the low-molecular gelling agent is present on at least a part of the surface of one or more members selected from the group consisting of a positive electrode, a negative electrode, and optionally a separator. The method of making it exist is as above-mentioned, for example. Preferably, the surface of the member is directly contacted with a composition containing a low-molecular gelling agent and a polymer binder, and more preferably, the member is immersed in the composition. In particular, when the member is a separator, by immersing the separator in the composition, the entire surface of the separator is wetted by the composition, the composition is impregnated into the separator, and a part of the holes that the separator has inside Or, the composition can penetrate all the way.

  Examples of the method for impregnating the separator with the composition include a dip method in which the separator is immersed in the composition in a tank in which the composition is contained, and a method in which the composition is placed on the separator and impregnated. . When the composition is in a gel form, a film of the composition can be prepared in advance, and the film can be placed on a separator and impregnated. When impregnation is performed, heating, pressurization, or reduced pressure tends to facilitate impregnation and tends to impregnate in a shorter time. Further, the impregnation amount of the low molecular weight gelling agent and the solvent may be adjusted by volatilizing a part or all of the solvent that can be contained in the composition after impregnation.

  In addition, in the state of an electrode (positive electrode and negative electrode) and a laminate described later in which separators are optionally laminated, a treatment for allowing a low-molecular gelling agent to exist on at least a part of the surface of the above member may be performed. You may perform the process which makes a low molecular gelling agent exist on the surface of at least one part of the said member in the state which accommodated the body in the battery case. In these treatments, in order to allow the low molecular gelling agent to be present on the surface of at least a part of the member, for example, the laminate is immersed in a composition containing the low molecular gelling agent and the polymer binder. Method, a method of spraying a composition containing a low-molecular gelling agent and a polymer binder on a laminate, and a composition containing a low-molecular gelling agent and a polymer binder from the cross-sectional direction of the laminate. And a method in which a composition containing a low-molecular gelling agent and a polymer binder is disposed near the laminate and diffused throughout the laminate.

  The low molecular gelling agent can be present on at least a part of the surface of the electrode by including a low molecular gelling agent and a polymer binder in the electrode mixture and coating on the electrode current collector. And can be sprayed. When the low molecular gelling agent is present in such a process, the preparation of the electrode and the operation of allowing the low molecular gelling agent to be performed can be performed simultaneously. This is preferable because it can be uniformly present in the system.

<Process (2) Laminate production process>
In this step (2), a positive electrode, a negative electrode, and optionally a separator are laminated to obtain a laminate including them. The method for producing the laminate can be performed by a known method. For example, the positive electrode and the negative electrode are wound in a laminated state with a separator interposed between them, and formed into a laminated body of a wound structure, or they are alternately laminated by bending or laminating multiple layers. It may be formed into a laminate in which a separator is interposed between the plurality of positive electrodes and negative electrodes. The separator, the positive electrode, and the negative electrode constituting the laminate may each independently have a low-molecular gelling agent present on at least a part of the surface, or may not exist. For example, the separator obtained in step (1) having a low-molecular gelling agent on at least a part of the surface is sandwiched between a positive electrode and a negative electrode having no low-molecular gelling agent on the surface, and laminated by the above method. May be.

  In step (2), a gel-like film formed from a composition containing a low-molecular gelling agent and a polymer binder is prepared in advance, and the film is sandwiched between a positive electrode and a negative electrode, and folded or laminated. At the same time as forming a laminate, the electrode can be impregnated with a low molecular gelling agent. Alternatively, a composite film in which the gel film and the separator are overlapped and a low molecular gelling agent may be impregnated inside the separator is prepared in advance, and the composite film is formed in the same manner as described above. Alternatively, a low molecular gelling agent may be impregnated inside the electrode. In the composite film, a gel-like film can be present on both sides of the separator, or a gel-like film can be present only on one side of the separator. The presence of a gel-like film on both sides of the separator is preferable because the effect brought about by the low-molecular gelling agent is high.

  Step (1) and step (2) may be step (2) after step (1), step (1) after step (2), and those steps. May be alternately repeated.

<Step (3) Immersion step in electrolyte>
In the step (3), the laminate obtained through the step (1) and the step (2) is immersed in an electrolytic solution. In this step (3), the laminate may be immersed in the electrolytic solution in the battery case (exterior). In this case, a lithium ion secondary battery can also be produced by injecting an electrolytic solution into the battery case and immersing and sealing the laminate in the electrolytic solution.

  Moreover, the laminated body which does not have a low molecular gelling agent on the surface of any of a positive electrode, a negative electrode, and a separator obtained through the step (2) is passed through the step (1), that is, with a low molecular gelling agent. A composition in which a low molecular gelling agent is present on at least a part of the surface of each member in the laminate after being immersed in a composition containing a polymer binder (but not including an electrolyte). The laminate may be immersed in the electrolytic solution by adding an electrolyte (for example, a lithium salt) to the product and, if necessary, other additives and a non-aqueous solvent to prepare an electrolytic solution. According to such a method, in the step (1), a composition containing a low-molecular gelling agent prepared to have a composition that easily penetrates into the inside of the separator (including pores) can be used. 3) is preferable because it can be adjusted to an optimum composition as the electrolytic solution.

  The shape of the lithium ion secondary battery of the present embodiment is not particularly limited, and for example, a cylindrical shape, an elliptical shape, a rectangular tube shape, a button shape, a coin shape, a flat shape, and a laminated shape are suitably employed.

  According to the present embodiment, it is possible to suppress an increase in labor and cost required for manufacturing a battery, maintain battery performance required for a lithium ion secondary battery, and adhesion between a separator and an electrode and / or between electrodes. By improving the adhesiveness, it is possible to provide a method for manufacturing a lithium ion secondary battery and a component for a lithium ion secondary battery, which sufficiently suppress the displacement and peeling of each other. In particular, in each process ranging from the battery manufacturing process to the transportation and transportation of the battery and the use in charging and discharging, the battery members are displaced or separated between the battery members (for example, between the electrode and the separator and between the electrodes). Can be sufficiently suppressed.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said embodiment. The present invention can be variously modified without departing from the gist thereof.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. Various characteristics of the lithium ion secondary battery component and the lithium ion secondary battery were measured and evaluated as follows.

(I) Adhesive evaluation In a battery case, a part containing a negative electrode or a negative electrode and a low molecular gelling agent, a part containing a separator or separator and a low molecular gelling agent, a positive electrode or a positive electrode and a low molecular gelling agent The laminated body which laminated | stacked the components containing these in this order was accommodated, electrolyte solution was further added there, and the small battery with an electrode diameter of 16 mm was produced and evaluated. A pressing member was arranged so that a force of 5 kgf / cm ² was applied in the stacking direction of the laminate, and a battery was produced. The battery was charged and discharged 100 cycles in a 25 ° C. environment. The charging / discharging conditions are CC-CV charging up to 4.2V at 1C and CC discharging conditions up to 3.0V at 1C. When charging and discharging are performed once, one cycle is counted. did. The battery after 100 cycles of charge and discharge were disassembled in a discharged state, and the adhesion between the separator and the electrodes or between the electrodes was evaluated. Evaluation was carried out by producing five batteries, and the results were judged as follows.
A: All batteries are sufficiently bonded, and even if the pressing member is removed, no bubbles or voids are observed between the members. Moreover, each member cannot be smoothly peeled off.
B: Adherent enough in any battery, and even if the pressing member is removed, no bubbles or voids are observed between the members. However, each member can be peeled smoothly.
C: Adhesiveness is insufficient in some but not all of the batteries, and when the pressing member is removed, there may be a deviation between the members.
D: Adhesiveness is insufficient in any battery, and when the pressing member is removed, deviation occurs between the members.

(Ii) Evaluation of charge / discharge characteristics of battery In a battery case, a part containing a negative electrode or a negative electrode and a low molecular gelling agent, a part containing a separator or separator and a low molecular gelling agent, a positive electrode or a positive electrode and a low molecular weight A laminate in which components including a gelling agent were laminated in this order was accommodated, and an electrolyte was further added thereto to produce and evaluate a small battery having an electrode diameter of 16 mm. The battery was charged and discharged 100 cycles in a 50 ° C. environment. The charging / discharging conditions are CC-CV charging up to 4.2V at 1C and CC discharging conditions up to 3.0V at 1C. When charging and discharging are performed once, one cycle is counted. did. The discharge capacity at the 100th cycle relative to the second cycle was calculated as the discharge capacity retention rate.

(Iii) Battery leakage test In a battery case, a part containing a negative electrode or a negative electrode and a low-molecular gelling agent, a part containing a separator or separator and a low-molecular gelling agent, a positive electrode or a positive electrode, and a low-molecular gel A laminated body in which components including an agent were laminated in this order was accommodated, and an electrolytic solution was further added thereto to produce and evaluate a single-layer laminated battery having an electrode size of 35 mm × 40 mm. The battery was formed with five 0.2 mmφ holes on the front and back sides, 20 G centrifugal force was applied, and the liquid retention rate was determined from the weight of the cell before and after application.

(Synthesis Example 1)
A compound represented by the following structural formula (I) (hereinafter also referred to as “compound (I)”) as a low-molecular gelling agent was synthesized as follows. The synthesis was performed according to the method described in International Publication No. 2010/095572.

(Synthesis Example 2)
A compound represented by the following structural formula (b) (hereinafter referred to as “compound (b)”) as a low-molecular gelling agent was synthesized by the same method as in Synthesis Example 1.

(Synthesis Example 3)
As a low molecular weight gelling agent, a compound represented by the following structural formula (c) (hereinafter referred to as “compound (c)”) is referred to Mol. Cryst. Liq. Cryst. Vol. 439, p209-220.

(Preparation Example 1 of Gelator-Containing Solution)
For 100 parts by mass of N-methyl-2-pyrrolidone, 5 parts by mass of the compound (i) synthesized in Synthesis Example 1 as a low molecular gelling agent, and vinylidene fluoride and hexafluoropropylene as polymer binders 5 parts by weight of a copolymer (PVdF-HFP copolymer, trade name “KYNAR series”) added to the mixture, heated to 95 ° C., uniformly mixed, then cooled to 25 ° C. A gelling agent-containing solution (a) was obtained.
(Preparation example 2 of gelling agent-containing solution)
A gelling agent-containing solution (b) was obtained in the same manner as in Preparation Example 1 of a gelling agent-containing liquid except that the compound (b) synthesized in Synthesis Example 2 was used as the gelling agent.
(Preparation Example 3 of Gelator-Containing Solution)
A gelling agent-containing solution (c) was obtained in the same manner as in Preparation Example 1 of the gelling agent-containing liquid, except that the compound (c) synthesized in Synthesis Example 3 was used as the gelling agent.

(Preparation Example 4 of Gelator-Containing Solution)
A gelling agent-containing liquid (d) was obtained in the same manner as in Preparation Example 1 of a gelling agent-containing liquid, except that PVdF-HFP copolymer as a polymer binder was not used.
(Preparation Example 5 of Gelator-Containing Solution)
A gelling agent-containing liquid (e) was obtained in the same manner as in Preparation Example 2 of the gelling agent-containing liquid, except that PVdF-HFP copolymer, which is a polymer binder, was not used.
(Preparation Example 6 of Gelator-Containing Solution)
A gelling agent-containing liquid (f) was obtained in the same manner as in Preparation Example 3 of the gelling agent-containing liquid except that the PVdF-HFP copolymer that is a polymer binder was not used.
(Preparation Example 7 of Gelator-Containing Liquid)
A gelling agent-containing liquid except that a copolymer (PAN-MMA) having 90:10 acrylonitrile and methyl methacrylate as monomers was used instead of the PVdF-HFP copolymer as the polymer binder. In the same manner as in Preparation Example 1, a gelling agent-containing liquid (g) was obtained.

(Production of positive electrode 1)
Lithium nickel, manganese and cobalt mixed oxide having a number average particle diameter of 11 μm as a positive electrode active material, graphite carbon powder having a number average particle diameter of 6.5 μm and acetylene black powder having a number average particle diameter of 48 nm as a conductive auxiliary agent, PVdF Were mixed at a mass ratio of mixed oxide: graphite carbon powder: acetylene black powder: PVdF = 100: 4.2: 1.8: 4.6. N-methyl-2-pyrrolidone was added to the obtained mixture so as to have a solid content of 68% by mass and further mixed to prepare a slurry solution. This slurry-like solution was applied to one side of an aluminum foil having a thickness of 20 μm, and the solvent was dried and removed, followed by rolling with a roll press. The rolled product was punched into a predetermined size to obtain a positive electrode (α).

(Production of parts including positive electrode and low-molecular gelling agent 1)
0.1 mL of the gelling agent-containing solution (a) was applied to the surface of the positive electrode (α) on which the active material was applied. Next, the coated product is allowed to stand for 10 minutes on a hot plate heated to 80 ° C., and a low molecular gelling agent is uniformly attached to the surface of the positive electrode. Further, with a vacuum dryer set at 80 ° C. N-methyl-2-pyrrolidone was removed by heating for 1 hour to obtain a part (α-2).

(Production of parts including positive electrode and low-molecular gelling agent 2)
Lithium nickel, manganese and cobalt mixed oxide having a number average particle diameter of 11 μm as a positive electrode active material, graphite carbon powder having a number average particle diameter of 6.5 μm and acetylene black powder having a number average particle diameter of 48 nm as a conductive auxiliary agent, PVdF -HFP and compound (b) are mixed oxide: graphite carbon powder: acetylene black powder: PVdF-HFP: compound (b) = 100: 4.2: 1.8: 4.6: 4.6 Mixed in ratio. N-methyl-2-pyrrolidone was added to the obtained mixture so as to have a solid content of 68% by mass and further mixed to prepare a slurry solution. This slurry-like solution was applied to one side of an aluminum foil having a thickness of 20 μm, and the solvent was dried and removed, followed by rolling with a roll press. The rolled product was punched into a predetermined size to obtain a part (α-3).

(Production of parts including positive electrode and low-molecular gelling agent 3)
The component (α-4) was prepared in the same manner as in Production 1 of the component containing the positive electrode and the low-molecular gelling agent except that the gelling agent-containing liquid (d) was applied instead of the gelling agent-containing liquid (a). Obtained.

(Preparation of negative electrode 1)
Graphite carbon powder (I) having a number average particle diameter of 12.7 μm and graphite carbon powder (II) having a number average particle diameter of 6.5 μm as a negative electrode active material, and a carboxymethyl cellulose solution (solid content concentration: 1.83 mass%) as a binder And diene rubber (glass transition temperature: −5 ° C., number average particle size upon drying: 120 nm, dispersion medium: water, solid content concentration 40% by mass), graphite carbon powder (I): graphite carbon powder ( II): Carboxymethylcellulose solution: Diene rubber = 90: 10: 1.44: 1.76 The solid content is mixed so that the total solid content concentration is 45% by mass, and the slurry solution is mixed. Prepared. The slurry solution was applied to one side of a 10 μm thick copper foil, and the solvent was removed by drying, followed by rolling with a roll press. The rolled product was punched into a predetermined size to obtain a negative electrode (β).

(Production of parts including negative electrode and low-molecular gelling agent 1)
0.1 mL of the gelling agent-containing solution (b) was applied to the surface of the negative electrode (β) on which the active material was applied. Next, the coated product was allowed to stand on a hot plate heated to 80 ° C. for 10 minutes to uniformly attach the low molecular weight gelling agent to the surface of the negative electrode, and further 1 in a vacuum dryer set at 80 ° C. Heating for a period of time removed N-methyl-2-pyrrolidone to obtain part (β-2).

(Production of parts including negative electrode and low-molecular gelling agent 2)
As a negative electrode active material, graphite carbon powder (I) having a number average particle diameter of 12.7 μm, graphite carbon powder (II) having a number average particle diameter of 6.5 μm, PVdF-HFP and a compound (C) are mixed with graphite carbon powder ( I): Graphite carbon powder (II): PVdF-HFP: Compound (C) = 90: 10: 3.2: Mixing so that the total solid content concentration is 45% by mass in the solid content mass ratio Thus, a slurry solution was prepared. The slurry solution was applied to one side of a 10 μm thick copper foil, and the solvent was removed by drying, followed by rolling with a roll press. The rolled product was punched into a predetermined size to obtain a part (β-3).

(Production of part containing negative electrode and low-molecular gelling agent 3)
A part (β-4) was obtained in the same manner as in Production of a part containing a negative electrode and a low molecular weight gelling agent except that the gelling agent-containing liquid (e) was applied instead of the gelling agent-containing liquid (b). It was.

(Production of parts including negative electrode and low molecular gelling agent 4)
A part (β-5) is obtained in the same manner as in Production of a part 1 containing a negative electrode and a low molecular weight gelling agent, except that the gelling agent-containing liquid (g) is applied instead of the gelling agent-containing liquid (b). It was.

(Preparation of separator 1)
A microporous membrane (thickness 25 μm, porosity 50%, pore diameter 0.1 μm to 1 μm) made of polyethylene was punched into a predetermined size to obtain a separator (γ).

(Production of parts including separator and low-molecular gelling agent 1)
After the separator (γ) is immersed in the gelling agent-containing liquid (a) and the separator (γ) is impregnated with the gelling agent-containing liquid (a), the solvent is sufficiently removed and the component (γ-2) Got.

(Production of parts including a separator and a low-molecular gelling agent 2)
After the separator (γ) is immersed in the gelling agent-containing liquid (b) and the separator (γ) is impregnated with the gelling agent-containing liquid (b), the solvent is sufficiently removed and the component (γ-3) Got.

(Preparation of electrolyte 1)
Ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 1: 2 to obtain a mixed solution. LiPF ₆ was added to this mixed solution so as to have a concentration of 1 mol / L to prepare a non-gelled electrolytic solution (X) (hereinafter, the electrolytic solution before addition of the gelling agent is referred to as “mother electrolytic solution”). ). 1 part by mass of the compound (I) synthesized in Synthesis Example 1 above as a gelling agent is added to 100 parts by mass of this mother electrolyte (X), heated to 95 ° C. and uniformly mixed, and then 25 ° C. The electrolyte solution (a) was obtained.

(Preparation of electrolyte 2)
2 parts by mass of the compound (C) synthesized in Synthesis Example 3 above as a gelling agent is added to 100 parts by mass of the mother electrolyte (X), heated to 80 ° C. and uniformly mixed, and then heated to 25 ° C. The temperature was lowered to obtain an electrolytic solution (b).

(Production Example 1)
Compact and single-layer laminate type lithium ion secondary battery using a component (α-2), a negative electrode (β), a separator (γ) and an electrolyte solution (X) containing a positive electrode and a low-molecular gelling agent (A) Was made.

(Production Example 2 to Production Example 15)
Table 1 shows a positive electrode or a part containing a positive electrode and a low-molecular gelling agent, a negative electrode or a part containing a negative electrode and a low-molecular gelling agent, a separator or a part containing a separator and a low-molecular gelling agent, and an electrolyte. Except for the above changes, small and single-layer laminate type lithium ion secondary batteries (A) to (SO) were produced in the same manner as in Production Example 1.

Example 1
Using the small battery (A) of Production Example 1, “(i) Evaluation of adhesion of each member” and “(ii) Evaluation of charge / discharge characteristics of battery” were performed. The results are shown in Table 2.

(Examples 2 to 12, Comparative Examples 1 to 3)
Except that the batteries were changed to the small batteries (A) to (SO) shown in Table 2, the same as in Example 1, "(i) Evaluation of adhesion of each member" and "(ii) Charging / discharging characteristics of the battery" Evaluation "was carried out. The evaluation results are shown in Table 2.

(Example 13)
Using the single-layer laminated battery (A) of Production Example 1, “(iii) Battery leakage test” was performed. The results are shown in Table 3.

(Examples 14 to 24, Comparative Examples 4 to 6)
“(Iii) Battery leakage test” was carried out in the same manner as in Example 1 except that the batteries were changed to the small batteries (A) to (SO) shown in Table 3. The evaluation results are shown in Table 3.

  As shown in the above examples, when a low-molecular gelling agent is used together with a polymer binder, high adhesiveness is recognized, which contributes to improving battery characteristics and safety.

  The present invention can suppress increase in labor and cost required for battery production, maintain battery performance required for a lithium ion secondary battery, and adhesion between a separator and an electrode and / or adhesion between electrodes. In a field where a method for manufacturing a lithium ion secondary battery and a component for a lithium ion secondary battery are required, which sufficiently suppresses them from shifting or peeling from each other there is a possibility.

Claims (20)

A positive electrode containing at least one material selected from the group consisting of materials capable of inserting and extracting lithium ions as a positive electrode active material; a material capable of inserting and extracting lithium ions as a negative electrode active material; and A negative electrode containing one or more materials selected from the group consisting of metallic lithium, and a method for producing a lithium ion secondary battery,
A step of causing a low molecular gelling agent to exist on at least a part of the surface of one or more members selected from the group consisting of the positive electrode and the negative electrode by a polymer binder;
Laminating the positive electrode and the negative electrode to obtain a laminate including them;
Immersing the laminate in an electrolytic solution;
Manufacturing method. Capable of containing a separator, a positive electrode containing at least one material selected from the group consisting of materials capable of inserting and extracting lithium ions as a positive electrode active material, and inserting and extracting lithium ions as a negative electrode active material And a negative electrode containing at least one material selected from the group consisting of lithium and metallic lithium, and a method for producing a lithium ion secondary battery comprising:
A step of causing a low-molecular gelling agent to exist on at least a part of the surface of one or more members selected from the group consisting of the separator, the positive electrode, and the negative electrode with a polymer binder;
Laminating by sandwiching the separator between the positive electrode and the negative electrode to obtain a laminate including them;
Immersing the laminate in an electrolytic solution;
Manufacturing method.   The manufacturing method of Claim 2 with which the said separator contains organic resin.   The said existing process WHEREIN: The said low molecular gelling agent is made to adhere to the said at least one part surface directly and / or via the said polymer binder. Production method.   5. The method according to claim 1, wherein in the step of presenting, the composition containing the low-molecular gelling agent and the polymer binder is brought into direct contact with at least a part of the surface of the member. The manufacturing method as described.   The manufacturing method according to claim 5, wherein the composition is a solution or a dispersion, and the dispersion is in a liquid, gel, or slurry form.   The manufacturing method according to claim 5 or 6, wherein in the step of presenting, the composition is directly brought into contact with at least a part of the surface of the member by immersing the member in the composition.   The composition is directly brought into contact with at least a part of a surface of the member included in the laminate or a structure including the laminate and a battery case containing the laminate in the step of presenting. The manufacturing method of any one of -7.   The said composition contains a positive electrode active material, The manufacturing method of any one of Claims 5-8 which makes this composition contact the positive electrode collector or the surface of a positive electrode directly in the step to make it exist.   The said composition contains a negative electrode active material, The manufacturing method as described in any one of Claims 5-9 which makes the said composition contact the negative electrode collector or the surface of a negative electrode directly in the step to make it exist.   The manufacturing method according to claim 5, wherein the composition further contains a lithium salt. The low molecular gelling agent includes one or more compounds selected from the group consisting of compounds represented by the following general formulas (1), (2), and (3). The production method according to item.
^{Rf 1 -R 1 -X 1 -L 1} -R 2 (1)
Rf ¹ -R ¹ -X ¹ -L ¹ -R ³ -L ² -X ² -R ⁴ -Rf ² (2)
^{R 5 -O-Cy-X 3} -Cm (3)
(In the formulas (1) and (2), Rf ¹ and Rf ² each independently represents a perfluoroalkyl group having 2 to 20 carbon atoms, and R ¹ and R ⁴ each independently represent a single bond or 1 carbon atom. To 6 divalent saturated hydrocarbon groups, wherein X ¹ and X ² are each independently the following formulas (1a), (1b), (1c), (1d), (1e), (1f) and ( 1g) represents a divalent group selected from the group consisting of groups represented by 1g), L ¹ and L ² are each independently a single bond, an alkyl group or an oxyalkylene group optionally substituted with a halogen atom, an alkyl An oxycycloalkylene group which may be substituted with a group or a halogen atom, or a divalent oxyaromatic group which may be substituted with an alkyl group or a halogen atom, and R ² represents an alkyl group or a halogen atom ( However, A fluoroalkyl group, an aryl group or a fluoro group optionally substituted with an alkyl group having 1 to 20 carbon atoms, an alkyl group or a halogen atom (excluding a fluorine atom) which may be substituted with An aryl group, or a monovalent group in which one or more of these groups and one or more of divalent groups corresponding to these groups are bonded, R ³ represents oxygen and And / or a C1-C18 divalent saturated hydrocarbon group which may have one or more sulfur atoms and may be substituted with an alkyl group.

In formula (3), R ⁵ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms in the main chain, and Cy represents a substituted or unsubstituted divalent aromatic group having 5 to 30 nucleus atoms. It shows the family hydrocarbon group or an alicyclic hydrocarbon group, X ³ is represented by the following formula (3a), (3b), (3c), (3d), (3e), (3f) and (3 g) A divalent group selected from the group consisting of the following groups, or a divalent group in which two or more of these divalent groups are bonded, and Cm is a monovalent group represented by the following general formula (3z) In the following formula (3z), a plurality of R ^a each independently represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.

) The production method according to claim 12, wherein X ¹ and X ² are each independently a divalent functional group represented by the formula (1a) or the formula (1d). The production method according to claim 11 or 13, wherein both of X ¹ and X ² are a divalent group represented by the formula (1d).   The manufacturing method of any one of Claims 1-14 whose said polymer binder is a polymer which has 1 or more types chosen from the group which consists of a halogen atom and a (meth) acryl group.   The polymer binder includes at least one selected from the group consisting of a polymer having a polyvinylidene fluoride moiety, a polymer having a (meth) acrylonitrile moiety, and a polymer having a (meth) acrylate moiety. The manufacturing method of any one of 1-15.   The manufacturing method of any one of Claims 1-16 in which the said electrolyte solution contains a nonaqueous solvent, lithium salt, a low molecular gelling agent, and a polymer binder. The electrolyte solution is a gel at a temperature below a predetermined temperature, and is a phase transition type gel electrolyte solution that is a sol at a temperature higher than the predetermined temperature,
The manufacturing method of Claim 17 which exists in the range whose said predetermined temperature is 50-150 degreeC.   A component for a lithium ion secondary battery, comprising at least one member selected from the group consisting of a positive electrode, a negative electrode, and a separator, and a low-molecular gelling agent present on at least a part of the surface of the member. Further comprising a polymeric binder;
The lithium ion secondary battery component according to claim 19, wherein the low-molecular gelling agent is attached to the at least part of the surface directly and / or via the polymer binder.

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