JP5711026B2 - LITHIUM ION SECONDARY BATTERY AND METHOD FOR PRODUCING LITHIUM ION SECONDARY BATTERY - Google Patents

Description

  The present invention relates to a member for a lithium ion secondary battery and a method for producing a lithium ion secondary battery using the same.

  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. In the lithium ion secondary battery, the positive electrode is LiCoO ₂ , LiNiO ₂ or LiMn ₂ O ₄ as a positive electrode active material, carbon black or graphite as a conductive agent, polyvinylidene fluoride, latex or rubber as a binder Is mixed with 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 started 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 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

As for lithium ion secondary batteries for automobiles, it is necessary to manufacture a larger amount of batteries than before, and there is a higher demand for improvement in productivity, production and stabilization of quality. However, the current lithium ion secondary battery has a problem that the arrangement of the electrode and the separator is shifted or the electrode and the separator are easily peeled off. If the electrode or separator is misaligned 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 include, for example, 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 taking into account the deviation. There are means for using electrodes and separators having sizes and shapes, and means for using an adhesive material such as an adhesive as described in Patent Document 4.

However, these means increase the labor and cost for manufacturing the battery, extremely reduce the other performance required for the lithium ion secondary battery, and do not sufficiently suppress the displacement of the arrangement. No satisfactory solution has yet been found.
Further, 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 is improved to some extent. However, since these electrolytes have low charge / discharge characteristics and their adhesiveness cannot be said to be sufficiently high, there are significant practical problems.

  Therefore, the present invention has been made in view of the above circumstances, and prevents the labor and cost of the battery from being increased, maintains the performance required for the lithium ion secondary battery, and provides the separator and the electrode. For lithium-ion secondary batteries that sufficiently suppress the displacement and peeling of battery components in each process, from battery production process to battery transportation and transportation and charge / discharge use, by improving adhesion An object is to provide a member and a method for producing a lithium ion secondary battery.

  As a result of studying various battery members to achieve the above object, the present inventors have used a member directly in contact with a composition containing a phase transition gelling agent as a separator and / or an electrode. As a result, the present inventors have completed the present invention.

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Ｒａ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。

）
［２］前記組成物は、溶液又は分散液であり、前記分散液は、液状、ゲル状又はスラリー状である、［１］の製造方法。
［３］前記存在させる工程において、前記組成物に前記部材を浸漬することにより、前記部材の少なくとも表面に前記組成物を直接接触させる、［１］又は［２］の製造方法。
［４］前記存在させる工程において、前記積層体、又は、前記積層体とそれを収容した電池ケースとを備える構造体における前記部材の少なくとも表面に前記組成物を直接接触させる、［１］〜［３］のいずれか１つの製造方法。
［５］前記相転移型ゲル化剤を含む組成物がリチウム塩を更に含む、［１］〜［４］のいずれか１つの製造方法。
［６］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、［１］〜［５］のいずれか１つの製造方法。
［７］前記Ｘ¹及びＸ²がいずれも、前記式（１ｄ）で表される２価の官能基である、［１］〜［６］のいずれか１つの製造方法。
［８］前記セパレータが有機樹脂を含む、［１］〜［７］のいずれか１つの製造方法。
［９］前記電解液が、非水溶媒と、リチウム塩と、相転移型ゲル化剤と、を含む、［１］〜［８］のいずれか１つの製造方法。
［１０］前記電解液が、ある温度以下の温度でゲルであり、そのある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、
前記ある温度が５０〜１５０℃の範囲にある、［９］の製造方法。
That is, the present invention is as follows.
[1] 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 step of allowing a phase transition gelling agent to be present on at least the surface of one or more members selected from the group consisting of the separator, the positive electrode, and the negative electrode;
After the step of presenting, the step of sandwiching the separator between the positive electrode and the negative electrode to obtain a laminate by stacking;
Immersing the laminate in an electrolytic solution;
Including
In the present step, the composition containing the phase transition type gelling agent is brought into direct contact with at least the surface of the member;
The manufacturing method in which the said phase transition type gelatinizer contains the 1 or more types of compound selected from the group which consists of a compound represented by the following general formula (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 Ra each independently represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.

)
[2] The method according to [1], wherein the composition is a solution or a dispersion, and the dispersion is a liquid, a gel, or a slurry.
[3] The method according to [1] or [2], wherein in the step of presenting, the composition is directly brought into contact with at least a surface of the member by immersing the member in the composition.
[4] In the step of causing the composition to exist, the composition is brought into direct contact with at least the surface of the member in the laminate or a structure including the laminate and a battery case containing the laminate. 3] Any one manufacturing method.
[5] The method according to any one of [1] to [4], wherein the composition containing the phase transition type gelling agent further contains a lithium salt.
[6] Any one of [1] to [5], wherein X ¹ and X ² are each independently a divalent functional group represented by the formula (1a) or the formula (1d). Production method.
[7] The production method of any one of [1] to [6], wherein both X ¹ and X ² are divalent functional groups represented by the formula (1d).
[8] The manufacturing method according to any one of [1] to [7], wherein the separator includes an organic resin.
[9] The production method according to any one of [1] to [8], wherein the electrolytic solution includes a nonaqueous solvent, a lithium salt, and a phase transition gelling agent.
[10] The electrolyte solution is a gel electrolyte solution of a phase transition type that is a gel at a temperature lower than a certain temperature and is a sol at a temperature higher than the certain temperature,
It said certain temperature is in the range of 50 to 150 ° C., the production method of [9].

  According to the present invention, it is possible to prevent the increase in labor and cost during the production of the battery, maintain the performance required for the lithium ion secondary battery, and improve the adhesion between the separator and the electrode, thereby producing the battery. Separator for lithium-ion secondary battery and method for producing lithium-ion secondary battery that sufficiently suppress the displacement or peeling of the battery components in each process ranging from battery transportation to transportation and use in charging and discharging Can be provided.

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. The method for producing a lithium ion secondary battery of the present embodiment includes a separator and 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, A method for producing a lithium ion secondary battery, comprising: 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, A step of allowing the phase transition type gelling agent to exist on at least the surface of one or more members selected from the group consisting of a separator, a positive electrode and a negative electrode; and sandwiching the separator between the positive electrode and the negative electrode to laminate them It includes a step of obtaining a laminated body and a step of immersing the laminated body in an electrolytic solution.

<Separator>
The separator according to the present embodiment is 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 preferably has a phase transition type gelling agent on at least the surface thereof, and 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 other than the phase transition gelling agent 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 material other than the phase transition type gelling agent for the separator 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.

In the present embodiment, from the viewpoint of improving the adhesion between the separator and the positive electrode and / or between the separator and the negative electrode, it is preferable that a phase transition gelling agent is present on at least the surface of the separator. Preferably, the surface of the separator is brought into direct contact with the composition containing the phase transition type gelling agent so that the phase transition type gelling agent is present at least on the surface. The presence of the phase transition type gelling agent on the surface of the separator means that the phase transition type gelling agent is in direct contact with the surface of the separator. Further, a phase transition type gelling agent may be present not only on the surface of the separator but also inside the separator. It is preferable that the gelling agent is present in 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 phase transition type gelling agent may be a network in which a 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. The composition may be a solution or a dispersion, and the dispersion may be liquid, gel, or slurry.
The method for causing the phase transition type gelling agent to be present on the separator surface is not particularly limited. For example, a method of cast-coating a composition containing the phase transition type gelling agent on the separator, including the phase transition type gelling agent is included. The method of immersing a separator in a composition is mentioned. According to these methods, it is possible to make the phase transition type 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 phase transition type gelling agent by the method of immersing the separator, it is easier to make the phase transition type gelling agent present inside the separator. If a phase transition type gelling agent is also present inside the separator (including pores), it is possible to improve the non-uniformity of the pore size and pore size distribution of the separator, which is advantageous from the viewpoint of contributing to stabilization of charge and discharge. is there. Further, the more the phase transition type 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 phase transition type gelling agent present 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 phase transition type gelling agent present in the separator can be determined, for example, by observing the separator in which the phase transition type gelling agent is present with an electron microscope and subjecting the observed image to image processing.

<Phase transition type gelling agent>
The phase transition type gelling agent used in the present embodiment is a gelling agent capable of forming a gel capable of sol-gel transition by reversible physical interaction. Here, the physical interaction includes, for example, temperature (heat) change, light irradiation, and pressure application. Phase transition type gelling agents can be distinguished into polymer type gelling agents and non-polymeric low molecular weight gelling agents. Typical examples of the polymer-type gelling agent include a copolymer containing polyvinylidene dichloride (PVdF) and PVdF, and a copolymer containing polyacrylonitrile (PAN) and PAN. Various low molecular gelling agents are known, and any of them may be used. Examples of the low molecular gelling agent include a fluoro gelling agent described in JP-A-10-175901, and an amide group-containing gelling described in JP2007-506833A and JP2009-155592A. Agent, Chem. Rev. Examples include various gelling agents described in Vol. 97, p3133-3159 (1997). A phase transition type gelling agent is used individually by 1 type or in combination of 2 or more types.

  The phase transition type gelling agent in the present embodiment preferably contains a low molecular weight gelling agent from the viewpoint of maintaining battery characteristics and handling properties.

The low molecular gelling agent used in the present embodiment is a compound 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 consisting of:
^{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. And preferred. 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 standpoint, 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 the following formula: The divalent group represented by (1d) is more preferable, and the 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 is preferable from the viewpoint of gelling ability and improving the safety 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”. The divalent aromatic group may be a carbocyclic group or a heterocyclic group. The carbocyclic 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 nuclear atoms, and includes, for example, 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. And a divalent 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, as R ² , 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 group And an alkyl group having 1 to 12 carbon atoms represented by This alkyl group 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-tri A decafluoro 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, a tetrafluorophenyl 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 embodiment, 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 the perfluoroalkyl group is a perfluoroalkyl group). It is more preferable that the 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 or may not be substituted with an alkyl group. A divalent saturated hydrocarbon group having 1 to 18 carbon atoms is shown. The said carbon number is preferable in it being 1-16, and more preferable in it being 2-14. The gelling ability can also be controlled by the number of carbon atoms in R ³ . Moreover, the carbon number of the said range is preferable from a viewpoint of a synthesis | combination and raw material acquisition.

Examples of the gelling agent having a perfluoro group include Rf ¹ -R ¹ —O—R ² , 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 (wherein Ar represents a divalent aromatic group; the same shall apply hereinafter), 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 fluoro An alkylene group, 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 (where 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 represents a divalent aromatic group; the same shall apply hereinafter), 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 (here And R ⁶ and R ⁷ each independently represents an alkylene group, the same shall apply hereinafter). 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”. This divalent aromatic hydrocarbon group may be a carbocyclic 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. A substituent of the divalent aromatic hydrocarbon group can be selected from the viewpoint of synthesis or 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 carbocyclic group has 6 to 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, and includes, for example, 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. And a divalent group.
Ar is preferably 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 an electrolyte solution. A group selected from the group consisting of a group, a biphenylene group, a naphthylene group, a terphenylene group, and an anthranylene group is more preferable.
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 has 5 to 30 nuclear 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 plurality of groups connected if the number of nuclear atoms is within the range, or has both a carbocyclic ring and a heterocyclic ring. You may have both with an alicyclic group.

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 a 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 further have a substituent. However, the monovalent hydrocarbon group includes the nonaqueous solvent in which the compound represented by the general formula (3) (hereinafter also referred to as “compound (3)”) is dissolved in the nonaqueous solvent. In order to make the electrolytic solution gel, it is preferably a hydrocarbon group such as an aralkyl group typified by a benzyl group that allows the compound (3) to be easily dissolved in a non-aqueous solvent. 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, and an alkyl group having 4 to 14 carbon atoms from the viewpoint of more effectively and reliably achieving the above effects in the present embodiment. Is more preferable. 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, a divalent group of any one of the groups represented by the following formulas (3a), (3e) and (3g) is preferable.

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 phase transition type gelling agent is used individually by 1 type or in combination of 2 or more types.

  The phase transition type 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 perfluoro group include, for example, International Publication No. 2007/083843, JP2007-191626A, JP2007-191627A, and JP2007-191661A. And with reference to the method described in WO2009 / 78268.

The gelling agent having a perfluoro group used in the present embodiment can be synthesized by the following scheme, for example. 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 a perfluoro 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), by dehydration condensation such as Mitsunobu reaction, it is a kind of gelling agent having a perfluoro group A compound represented by the 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 general formula (IIIa), when Y ¹ and / or Y ² is a sulfur atom, the sulfur atom is further sulfonylated or sulfoxided to form a gel having a perfluoro group A compound represented by the following general formula (IVa), which is another kind of 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 method for synthesizing the gelling agent having a perfluoro 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 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).

ナスフラスコにおいて、化合物（ａ）をエタノール及びトルエンの混合溶液に溶かして、Ｐｄ／Ｃの存在下、水素添加反応を行う。水素添加反応後、Ｐｄ／Ｃを濾取し、濾液をエバポレーターで濃縮する。析出した固体をトルエンで再結晶を行い、黄色固体の化合物（ｂ）を得る。 (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).

ナスフラスコにおいて、５℃の氷冷下、１２Ｎの塩酸水溶液を調製する。当該水溶液中に、化合物（ｂ）及び亜硝酸ナトリウム（ＮａＮＯ₂）を加えて、２０分間攪拌する。さらに、フェノール、水酸化ナトリウム及び水の混合溶液を加えて攪拌する。析出した固体をトルエンで再結晶を行い、化合物（ｃ）を得る。 (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).

ナスフラスコにおいて、化合物（ｃ）を３−ペンタノンに溶解する。得られた溶液中に、１−ブロモオクタン及び炭酸カリウムを加えて１５時間還流を行う。得られた固体をトルエンで再結晶させ、カラムクロマトグラフィーで精製して化合物（３Ｉ）を得る。なお、上記カラムクロマトグラフィーにおいて、充填剤としてシリカゲルを用い、展開溶媒としてクロロホルムを用いる。 (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.

ナスフラスコにおいて、化合物（ｃ）を３−ペンタノンに溶解する。得られた溶液中に、１−ブロモヘキサン及び炭酸カリウムを加えて１５時間還流を行う。得られた固体をトルエンで再結晶を行い、カラムクロマトグラフィーで精製して化合物（３ＩＩ）を得る。なお、上記カラムクロマトグラフィーにおいて、充填剤としてシリカゲルを用い、展開溶媒としてクロロホルムを用いる。 [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.

<Solvent>
In the production method of the present embodiment, when a phase transition type gelling agent is present on the surface of the separator or the positive electrode or negative electrode described later, the solution or dispersion as a composition in which those members contain the phase transition type gelling agent A phase transition type gelling agent may be present on the surface by being immersed in the liquid. A slurry-like or gel-like dispersion may be used as the dispersion. The composition containing the phase transition type gelling agent preferably contains a nonaqueous solvent, and the phase transition type gelling agent is preferably dissolved or dispersed in the nonaqueous solvent.
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, N, N-dimethylacetamide, N, N-dimethylformamide, amides 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, trifluoromethylethylene Carbonate, 4,5-difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate Carbonates such as carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate and methyl trifluoroethyl carbonate, nitriles such as acetonitrile, propionitrile, adiponitrile and methoxyacetonitrile, N-methylpyrrolidone (NMP) And lactams such as sulfolane, sulfolanes such as sulfolane and 3-methylsulfolane, 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 a dialkylimidazolium cation and a trialkylimidazolium cation, a tetraalkylammonium ion, an alkylpyridinium ion, a dialkylpyrrolidinium ion, and a 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.

  The content of the phase transition type gelling agent in the composition containing the phase transition type gelling agent used in the present embodiment is arbitrary, but when the composition contains a nonaqueous solvent, the content ratio to the nonaqueous solvent ( The phase transition type gelling agent / non-aqueous solvent) is preferably 0.01 to 50 and more preferably 0.1 to 20 on a mass basis. When the content ratio of these components is within the range, the adhesion between the separator and the positive electrode or the negative electrode can be easily increased.

  It is preferable that the composition containing the phase transition type gelling agent according to the present embodiment further contains 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 uses a material containing 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). 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.

  From the viewpoint of improving the adhesion between the separator and the positive electrode, the positive electrode of the present embodiment preferably has a phase transition type gelling agent on the surface thereof. The presence of the phase transition type gelling agent on the surface of the positive electrode means that the phase transition type gelling agent is in direct contact with the surface of the positive electrode. It is preferable that the gelling agent is present in an area of 0.01% or more and 10% or less with respect to the entire surface area of the positive electrode because both battery characteristics and adhesiveness can be achieved at a high level. The presence state of the phase transition type gelling agent may be a network in which a 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.

  The method for causing the phase transition type gelling agent to be present on the surface of the positive electrode is not particularly limited. For example, a method of casting a composition containing the phase transition type gelling agent on the positive electrode, a phase transition type in the positive electrode mixture Examples thereof include a method of coating by mixing a gelling agent and a method of immersing the positive electrode in a composition containing a phase transition type gelling agent. Alternatively, the gelling agent can be present on the surface of the positive electrode by mixing the electrolytic solution and the phase transition gelling agent. According to these methods, the phase transition type gelling agent can be present not only on the surface of the positive electrode but also inside the positive electrode. In particular, since the positive electrode is impregnated with the composition containing the phase transition type gelling agent by the method of immersing the positive electrode, it is easier to make the phase transition type gelling agent present inside the positive electrode. The presence of the phase transition type gelling agent in the positive electrode is advantageous from the viewpoint that the adhesion and affinity between the phase transition type gelling agent and the positive electrode become stronger. Since the phase transition type gelling agent may be the same as described above, a detailed description thereof is omitted here. In the process of producing a lithium ion secondary battery, when a phase transition type gelling agent is present on the surfaces of both the separator and the positive electrode, the phase transition type gelling agents are different even if they are the same as each other. It may be a thing.

<Negative electrode>
In the lithium ion secondary battery of the present embodiment, the negative electrode uses one or more materials selected from the group consisting of a material capable of inserting and extracting lithium ions and a metallic lithium as a negative electrode active material. 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 or a binder to the negative electrode active material, if 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.

From the viewpoint of improving the adhesion between the separator and the negative electrode, the negative electrode of the present embodiment preferably has a phase transition type gelling agent on the surface thereof. The presence of the phase transition type gelling agent on the surface of the negative electrode means that the phase transition type gelling agent is in direct contact with the surface of the negative electrode. It is preferable that the gelling agent is present in an area of 0.01% or more and 10% or less with respect to the entire surface area of the negative electrode, since both battery characteristics and adhesiveness can be achieved at a high level. The presence state of the phase transition type gelling agent may be a network in which a 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.
The method for causing the phase transition type gelling agent to be present on the negative electrode surface is not particularly limited. For example, a method of casting a composition containing the phase transition type gelling agent on the negative electrode, a phase transition type in the negative electrode mixture Examples thereof include a method of coating by mixing a gelling agent and a method of immersing the negative electrode in a composition containing a phase transition gelling agent. Alternatively, the gelling agent can be present on the negative electrode surface by mixing the electrolyte and the phase transition gelling agent. According to these methods, it is possible to make the phase transition type gelling agent exist not only on the surface of the negative electrode but also inside the negative electrode. In particular, since the negative electrode is impregnated with the composition containing the phase transition type gelling agent by the method of immersing the negative electrode, it is easier to make the phase transition type gelling agent present inside the negative electrode. The presence of a phase transition type gelling agent also in the negative electrode is advantageous from the viewpoint that the adhesion and affinity between the phase transition type gelling agent and the positive electrode become stronger. Since the phase transition type gelling agent may be the same as described above, a detailed description thereof is omitted here. In the process of manufacturing a lithium ion secondary battery, when a phase transition type gelling agent is present on the surfaces of both the separator and the negative electrode, the phase transition type gelling agents are different even if they are the same as each other. It may be a thing.

Examples of the conductive aid used as necessary in the production of the positive electrode and the negative electrode include graphite, carbon black typified by acetylene black and ketjen black, and carbon fiber. 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, styrene butadiene rubber, and fluorine rubber.
<Electrolyte>
The electrolytic solution used in this embodiment preferably contains (I) a nonaqueous solvent and (II) a lithium salt.
(I) Although various things can be used as a non-aqueous solvent, for example, an aprotic solvent is mentioned. 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; tetrahydrofuran, crown ether And cyclic ethers represented by dioxane; represented by methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate and methyl trifluoroethyl carbonate. Chain carbonates; nitriles typified by acetonitrile and propionitrile; chain ethers typified by dimethyl ether, dimethoxyethane, glyme and fluorine-containing ethers; chain carboxylic acid esters typified by methyl propionate; chain ethers Examples include carbonate compounds, 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 a dialkylimidazolium cation and a trialkylimidazolium cation, a tetraalkylammonium ion, an alkylpyridinium ion, a dialkylpyrrolidinium ion, and a 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 and dicyanoamine anion can be used.

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 integer], represented by _{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 2)} 2 Examples thereof include lithium bisoxalyl borate, lithium difluorooxalyl borate represented by LiBF ₂ (C ₂ O ₂ ), and lithium trifluorooxalyl phosphate represented by LiPF ₃ (C ₂ O ₂ ).

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] are used from the viewpoint of enhancing gelation ability in addition to battery characteristics and stability. preferable.

  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 phase transition type gelling agent. When the electrolytic solution contains a phase transition type gelling agent, it is particularly excellent in satisfying the safety and battery characteristics required for a lithium ion secondary battery, and therefore, it is preferably used in a lithium ion secondary battery. Moreover, when electrolyte solution contains a phase transition type gelatinizer, the electrolyte solution may serve as the composition containing the said phase transition type gelatinizer.
Although the content of the phase transition type gelling agent is arbitrary, the content ratio of the phase transition type 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 is more preferably 0.3: 99.7 to 5:95. When the content ratio of these components is within the 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 phase transition type gelling agent may be the same as described above, a detailed description thereof is omitted here.

  The electrolyte solution containing a phase transition type gelling agent used in this embodiment is an 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 below a certain temperature and a sol at a temperature higher than the certain temperature. 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 certain 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 mixing ratio of the non-aqueous solvent, the lithium salt that is the electrolyte, and the phase transition gelling agent can be selected according to the purpose, but both the concentration of the electrolyte and the content of the phase transition gelling agent are within the above preferred ranges, Furthermore, it is desirable to be in a more preferable range. By producing an electrolytic solution with such a composition, battery characteristics and handleability can be further improved.

  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, and the phase transition type gelling agent is not limited. For example, after preparing a preliminary electrolyte by mixing a predetermined amount of electrolyte and a non-aqueous solvent, a phase transition gelling agent can be mixed with the preliminary electrolyte to obtain the electrolyte used in the present embodiment. . 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 that the electrolytic solution containing the phase transition type gelling agent is once heated and cooled to room temperature in a state where the components in the mixture are 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 phase transition type gelling agent exists between the positive electrode 120 and the separator 110 and / or between the negative electrode 130 and the separator 110. The positive electrode 120 and the separator 110 and / or the negative electrode 130 and the separator 110 are bonded by the gelling 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 may be the same as the manufacturing method of the conventional lithium ion secondary battery except having the following steps.
<Step (1) Step in which a phase transition type gelling agent is present>
In this step (1), the phase transition type gelling agent is present on at least the surface of one or more members selected from the group consisting of a separator, a positive electrode and a negative electrode. 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 phase transition type gelling agent, 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 the form of a gel, a film of the composition can be prepared in advance and placed on a separator for impregnation. When impregnation is performed, heating, pressurization, or reduced pressure tends to be impregnated, and the impregnation tends to be performed in a shorter time. Further, the impregnation amount of the phase transition type 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 the impregnation.

  In addition, in a state of a laminated body described later in which a separator and each electrode are laminated, a treatment for allowing a phase transition type gelling agent to exist on at least the surface of the above member may be performed, and the laminated body is housed in a battery case. Then, a treatment for causing the phase transition type gelling agent to exist on at least the surface of the member may be performed. In these treatments, in order for the phase transition type gelling agent to be present on at least the surface of the member, for example, a method of immersing the laminate in a composition containing the phase transition type gelling agent, a phase transition type gelling agent A method of spraying a composition containing a composition on a laminate, a method of injecting a composition containing a phase transition type gelling agent from a cross-sectional direction of the laminate, and a composition containing a phase transition type gelling agent arranged near the laminate The method of making it exist by diffusing to the whole laminated body is mentioned.

<Process (2) Laminate production process>
In this step (2), by sandwiching the separator between the positive electrode and the negative electrode, they are laminated to obtain a laminate. The method for producing the laminate can be performed by a known method. For example, a plurality of positive electrodes in which a positive electrode and a negative electrode are wound in a laminated state with a separator interposed therebetween to be formed into a laminate having a wound structure, or they are alternately laminated by bending or laminating a plurality of layers. Or a laminate in which a separator is interposed between the electrode and the negative electrode. The separator, the positive electrode, and the negative electrode constituting the laminate may each independently have a phase transition type gelling agent present on at least the surface thereof, or may not exist. For example, the separator obtained in the step (1) having at least the surface transition type gelling agent on the surface is sandwiched between the positive electrode and the negative electrode not having the phase transition type gelling agent on the surface, and laminated by the above method. Also good.
In the step (2), a gel film formed from a composition containing a phase transition type gelling agent is prepared in advance, and a separator and a gel film are stacked between a positive electrode and a negative electrode. The separator can be impregnated in the separator simultaneously with the formation of the laminate by lamination. When the separator and the gel film are stacked, the gel film can be present on both sides of the separator, or the gel film can be present only on one side of the separator. The presence of a gel film on both sides of the separator is preferable because the effect brought about by the phase transition gelling agent is high.

<Step (3) Immersion step in electrolyte>
In step (3), the laminate obtained through 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.
In addition, the laminate obtained through the step (2) and having no phase transition type gelling agent on any of the surfaces of the positive electrode, the negative electrode, and the separator is subjected to the step (1), that is, the phase transition type gelation. After immersing in a composition containing an agent (but not including an electrolyte) to allow a phase transition gelling agent to exist on at least the surface of each member in the laminate, a lithium salt is added to the immersed composition, and The laminate may be immersed in the electrolytic solution by adding other additives and a nonaqueous solvent as necessary to produce the electrolytic solution. According to such a method, in the step (1), a composition containing a phase transition type gelling agent can be used in a composition that easily penetrates into the inside of the separator (including pores). In the step (3), Since it can also adjust to an optimal composition as electrolyte solution, it is preferable.

  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.

  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 separator and the lithium ion secondary battery were measured and evaluated as follows.

(I) Evaluation of separator adhesion (1)
The electrode was mounted on the separator used for evaluation, and the adhesion between the separator and the electrode was evaluated after pressing the electrode toward the separator with a force of 5 kgf / cm ² for 3 seconds. The result was judged as follows.
A: Even if the separator is lifted upside down (that is, with the separator facing up and the electrode facing down), the electrode does not peel off.
B: The separator does not deviate from the electrode even after the pressure is released, but the electrode peels when the separator is lifted upside down.
C: When the pressure is released, the separator is displaced from the electrode.

(Ii) Separation evaluation of separator (2)
A battery is manufactured by arranging a pressing member on a laminate in which a negative electrode, a separator, and a positive electrode are laminated in this order so that a force of 5 kgf / cm ² is applied in the laminating direction. The battery is charged and discharged in a 25 ° C. environment. 100 cycles were performed. It should be noted that CC-CV charge up to 4.2 V at 1 C—CC discharge conditions up to 3.0 V at 1 C. When charging and discharging are performed once, each cycle is counted as one cycle. The battery after 100 cycles of charge and discharge were disassembled in a discharged state, and the adhesion between the separator and the electrode was evaluated. Evaluation was carried out by producing five batteries, and the results were judged as follows.
A: In any battery, the electrode and the separator are sufficiently bonded, and even if the pressing member is removed, there is no deviation between them.
B: In some but not all batteries, the adhesion between the positive electrode and / or the negative electrode and the separator is insufficient, and when the pressing member is removed, there is a deviation between them. .
C: In any battery, the adhesion between the electrode and the separator is insufficient, and when the pressing member is removed, a deviation occurs between them.

(Synthesis Example 1)
As a phase transition type gelling agent, a compound represented by the following structural formula (I) (hereinafter also referred to as “compound (I)”) was synthesized as follows. The synthesis was performed by the method described in International Publication No. 2010/095572.

(Synthesis Example 2)
As a phase transition type gelling agent, a compound represented by the following structural formula (b) (hereinafter referred to as “compound (b)”) was synthesized by the same method as in Synthesis Example 1.

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

(Production Example 1)
<Preparation of electrolyte>
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.
In the electrolyte solution (a), the sol-gel transition started from 92 ° C. when the temperature was lowered.

(Production Example 2)
1 part by mass of the compound (b) synthesized in Synthesis Example 2 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 brought to 25 ° C. The temperature was lowered to obtain an electrolytic solution (b).
In the electrolyte (b), the sol-gel transition started from 76 ° C. when the temperature was lowered.

(Production Example 3)
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 (c).
In the electrolyte solution (c), the sol-gel transition started from 75 ° C. when the temperature was lowered.

(Production Example 4)
To 100 parts by mass of N-methyl-2-pyrrolidone, 5 parts by mass of the compound (i) synthesized in Synthesis Example 1 above as a gelling agent is added, heated to 95 ° C. and uniformly mixed, and then 25 ° C. To obtain a gelling agent-containing solution (d).

<Preparation of positive electrode>
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, and a binder Polyvinylidene fluoride (PVDF) as a 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 disk shape having a diameter of 16 mm to obtain a positive electrode (α).

  Further, 0.1 mL of the gelling agent-containing solution (d) was applied to the surface on which the active material was applied to the positive electrode (α). Next, the coated product is allowed to stand on a hot plate heated to 80 ° C. for 10 minutes, so that the solution is uniformly immersed on the positive electrode surface, and further heated for 1 hour in a vacuum dryer set at 80 ° C. N-methyl-2-pyrrolidone was removed to obtain a positive electrode (α-2).

<Production of negative electrode>
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 disk shape with a diameter of 16 mm to obtain a negative electrode (β).

  Further, 0.1 mL of the gelling agent-containing solution (d) was applied to the surface on which the active material was applied to the negative electrode (β). Next, the coated product is allowed to stand for 10 minutes on a hot plate heated to 80 ° C. to make the solution immersed uniformly on the negative electrode surface, and further heated for 1 hour in a vacuum dryer set at 80 ° C. N-methyl-2-pyrrolidone was removed to obtain a negative electrode (β-2).

<Preparation of separator>
As a separator, a microporous membrane made of polyethylene (film thickness 25 μm, porosity 50%, pore diameter 0.1 μm to 1 μm) was punched into a disk shape having a diameter of 24 mm to obtain a separator (γ).

Example 1
The electrolytic solution (a) was heated to 95 ° C., and the separator (γ) was immersed therein for 1 minute and then taken out. The temperature was lowered to room temperature to obtain a separator (A). On the separator (A), the positive electrode (α) was placed such that the active material layer was on the separator side, and (i) separator adhesion evaluation (1) was performed. The evaluation results are shown in Table 1.

（実施例２〜４、比較例１〜４）
電解液を表１に記載のものに変更した以外は実施例１と同様にして、セパレータ（Ｂ）、（Ｃ）及び（Ｄ）を作製した。また、電極とセパレータとの組合せを表１に示すように変更して（ｉ）セパレータの接着性評価（１）を実施した。評価結果を表１に示す。

(Examples 2-4, Comparative Examples 1-4)
Separators (B), (C), and (D) were produced in the same manner as in Example 1 except that the electrolytic solution was changed to that shown in Table 1. Moreover, the combination of an electrode and a separator was changed as shown in Table 1, and (i) separator adhesion evaluation (1) was performed. The evaluation results are shown in Table 1.

(Examples 5 to 10)
A separator was produced in the same manner as in Example 1 except that the electrolytic solution was changed to that shown in Table 2. Moreover, the combination of an electrode and a separator was changed as shown in Table 2, and (i) separator adhesion evaluation (1) was performed. The evaluation results are shown in Table 2.

(Example 11)
<Battery assembly>
The laminate obtained by laminating the separator (γ) between the positive electrode (α) and the negative electrode (β) produced as described above was inserted into a SUS disk type battery case. Next, 0.5 mL of the electrolytic solution (a) heated to 95 ° C. was injected into the battery case, and the laminate was immersed in the electrolytic solution (a). Thereafter, the battery case was sealed to produce a lithium ion secondary battery (small battery). In the battery, a spring as a pressing member was placed on the stacked body so that a pressing force of 5 kgf / cm ² was applied in the stacking direction of the stacked body. The lithium ion secondary battery was held at 80 ° C. for 2 hours, and then cooled to 25 ° C. to obtain a lithium ion secondary battery (1).

  The lithium ion secondary battery (1) was evaluated by the method of (ii) separator adhesion evaluation (2). The evaluation results are shown in Table 3. In addition, since the separator (γ) was immersed in the electrolytic solution (a), the separator after immersion was used as the separator (A) in the table in the same manner as described above.

(Examples 12 to 20, Comparative Example 5, Comparative Example 6)
A lithium ion secondary battery was produced in the same manner as in Example 11 except that the battery member described in Table 3 was used. (Ii) Separation evaluation of separator for the battery in the same manner as in Example 11. Evaluation was made by the method (2). The evaluation results are shown in Table 3. The separator (γ) is immersed in the electrolytic solution (b), the separator is immersed in the electrolytic solution (c), and the separator is immersed in the mother electrolytic solution (X). Inside, the separator after immersion was made into the separator (B), (C), and (D) similarly to the above-mentioned.

  As shown in the above examples, when a member having a phase transition type gelling agent at least on the surface is used, high adhesiveness is recognized.

  The lithium ion secondary battery and lithium ion secondary battery member of the present invention are used as rechargeable batteries for automobiles such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles, in addition to portable devices such as mobile phones, portable audio devices, and personal computers. Is expected to be used.

  DESCRIPTION OF SYMBOLS 100 ... Lithium ion secondary battery, 110 ... Separator, 120 ... Positive electrode, 130 ... Negative electrode, 140 ... Positive electrode collector, 150 ... Negative electrode collector, 150 ... Battery case.

Claims (10)

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 one or more materials selected from the group consisting of metallic lithium and a lithium ion secondary battery,
A step of allowing a phase transition gelling agent to be present on at least the surface of one or more members selected from the group consisting of the separator, the positive electrode, and the negative electrode;
After the step of presenting, the step of sandwiching the separator between the positive electrode and the negative electrode to obtain a laminate by stacking;
Immersing the laminate in an electrolytic solution;
Including
In the present step, the composition containing the phase transition type gelling agent is brought into direct contact with at least the surface of the member;
The manufacturing method in which the said phase transition type gelatinizer contains the 1 or more types of compound selected from the group which consists of a compound represented by the following general formula (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 Ra each independently represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.

)   The manufacturing method according to claim 1, wherein the composition is a solution or a dispersion, and the dispersion is in the form of a liquid, a gel, or a slurry.   The manufacturing method according to claim 1 or 2, wherein in the step of presenting, the composition is directly brought into contact with at least a surface of the member by immersing the member in the composition.   4. The method according to claim 1, wherein, in the step of causing the composition to exist, the composition is directly brought into contact with at least a surface of the member in the laminate or a structure including the laminate and a battery case containing the laminate. 2. The production method according to item 1.   The manufacturing method of any one of Claims 1-4 with which the composition containing the said phase transition type gelatinizer further contains lithium salt. The production method according to claim 1, 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 1, wherein both X ¹ and X ² are a divalent functional group represented by the formula (1d).   The manufacturing method of any one of Claims 1-7 in which the said separator contains organic resin.   The manufacturing method of any one of Claims 1-8 in which the said electrolyte solution contains a nonaqueous solvent, lithium salt, and a phase transition type gelatinizer. The electrolyte solution is a gel at a temperature below a certain temperature, and is a phase transition type gel electrolyte solution that is a sol at a temperature higher than the certain temperature,
The manufacturing method according to claim 9, wherein the certain temperature is in a range of 50 to 150 ° C.

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