JP6221201B2 - Non-aqueous electrolyte and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte solution and a secondary battery including the non-aqueous electrolyte solution. More specifically, the present invention relates to a non-aqueous electrolyte solution containing a compound having a carbon-carbon triple bond and a non-aqueous electrolyte solution including the non-aqueous electrolyte solution. Next battery.

  Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are widely used as power sources for so-called portable electronic devices such as mobile phones and notebook computers, to in-vehicle power sources for automobiles and large power sources for stationary applications. It is being put into practical use. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, high temperature storage characteristics, cycle characteristics, and the like.

  A non-aqueous electrolyte used for a non-aqueous electrolyte secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

  In addition, various nonaqueous solvents, electrolytes, auxiliaries, and the like have been proposed in order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low temperature characteristics of batteries using these nonaqueous electrolyte solutions. . For example, by using vinylene carbonate and its derivatives, or vinyl ethylene carbonate derivatives, cyclic carbonates with double bonds react preferentially with the negative electrode to form a good quality film on the negative electrode surface, thereby preserving the battery. Patent Documents 1 and 2 disclose that characteristics and cycle characteristics are improved.

  Further, for example, Patent Document 3 discloses that by using a specific ethylene carbonate derivative, a triple bond-containing compound and / or a pentafluorophenyloxy compound, gas generation is reduced and cycle characteristics are improved. Yes.

JP-A-8-45545 JP-A-4-87156 International Publication No. 2006/077763

Eur. J. et al. Org. Chem. 2003, 4980-4990

However, the demand for higher performance of batteries in recent years is increasing, and it is required to achieve high capacity, high temperature storage characteristics, and cycle characteristics at a high level. For example, during a high-temperature durability test such as a high-temperature cycle or high-temperature storage, the negative electrode film is thermally eluted or decomposed and eluted in the electrolyte solution. On the negative electrode surface where the coating is eluted and exposed, further reductive decomposition of the electrolytic solution occurs. Such a reductive decomposition component of the negative electrode coating or the electrolytic solution diffuses in the electrolytic solution and is oxidatively decomposed on the surface of the positive electrode, leading to problems that the battery capacity is reduced and gas is generated.

  In particular, the oxidative decomposition of the negative electrode coating or the reductive decomposition component of the electrolytic solution tends to become prominent when the potential at which the positive electrode active material inserts and desorbs lithium increases. For example, when it is used for a non-aqueous electrolyte battery with a battery design in which the voltage is increased in order to increase the battery capacity and output, the battery currently on the market (the battery voltage at full charge in the volume zone is approximately 4. These oxidation reactions are more prominent than in 2V).

  In addition, as an alternative method for increasing the capacity of a non-aqueous electrolyte battery, it has been studied to pack as many active materials as possible in a limited battery volume. In batteries designed to increase the density or reduce the volume other than the active material in the battery as much as possible, the voids inside the battery are reduced, and the internal pressure of the battery increases significantly even when a small amount of gas is generated by oxidative decomposition. The battery capacity may decrease due to the expansion of the battery or the battery itself may become unusable due to the operation of the safety valve.

  In the non-aqueous electrolyte secondary battery using the electrolytic solution described in Patent Documents 1 to 3, the durability of the negative electrode film is not yet satisfactory, battery durability such as cycle characteristics and high-temperature storage characteristics, particularly It was necessary to improve durability during high voltage operation.

  Accordingly, the present invention solves the above-mentioned various problems that are expressed with respect to the required performance of secondary batteries in recent years, and in particular, provides a non-aqueous electrolyte solution with improved durability characteristics such as cycle and storage, And it is providing the non-aqueous electrolyte battery using this non-aqueous electrolyte.

As a result of intensive studies to solve the above-mentioned problems, the inventors have included a specific compound in the non-aqueous electrolyte used in the non-aqueous electrolyte battery, so that durability characteristics such as cycle and storage can be obtained. The present inventors have found that a non-aqueous electrolyte battery with improved can be realized, and have completed the present invention.
That is, the gist of the present invention is as follows.

（上記一般式（１）中、Ｒ₁は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。Ｒ₂はそれぞれ同一であっても異なっていても、また互いに結合して環構造を形成していてもよく、水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。ｍ、ｎは０以上５以下の整数である。Ｗは下記一般式（２）で表される何れか基であって、Ｒ_３は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示し、Ｗが２つのＲ_３を有する場合、Ｒ_３はそれぞれ同一であっても異なっていても、また互いに結合して環構造を形成していてもよい。）

（Ｘ₁、Ｘ₂はそれぞれ下記一般式（３）で表される何れかの基であって、Ｒはそれぞれ同一であっても異なっていてもよく、ヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。）

ｂ）前記一般式（１）で表される化合物が下記一般式（４）で表される３−ブチン−１，２−ジオール誘導体であることを特徴とする、請求項１に記載の非水系電解液。（請求項２）

（上記一般式（４）中、Ｘ₁、Ｘ₂はそれぞれ前記一般式（３）で表される何れかの基であって、Ｒはそれぞれ同一であっても異なっていてもよく、ヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。）
ｃ）前記一般式（４）で表される３−ブチン−１，２−ジオール誘導体が、少なくとも下記一般式（５）〜（８）で表される化合物の何れか一つであることを特徴とする、請求項２に記載の非水系電解液。（請求項３）

ｄ）非水系電解液中に前記一般式（１）で表される化合物が０．０１〜５．０質量％含有されていることを特徴とする、請求項１乃至３の何れか１項に記載の非水系電解液。（請求項４）
ｅ）リチウムイオンを吸蔵放出可能な負極及び正極、並びに非水系電解液を含む非水系電解液電池であって、前記非水系電解液が請求項１乃至４の何れか１項に記載の非水系電解液であることを特徴とする、非水系電解液電池。（請求項５）
ｆ）下記一般式（１）で表される化合物。（請求項６）

（上記一般式（１）中、Ｒ₁は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。Ｒ₂はそれぞれ同一であっても異なっていても、また互いに結合して環構造を形成していてもよく、水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。ｍ、ｎは０以上５以下の整数である。Ｗは下記一般式（２）で表される何れかの基であって、Ｒ_３は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示し、Ｗが２つのＲ_３を有する場合、Ｒ_３はそれぞれ同一であっても異なっていても、また互いに結合して環構造を形成していてもよい。）

（Ｘ₁、Ｘ₂はそれぞれ下記一般式（３）で表される何れか基であって、Ｒはそれぞれ同一であっても異なっていてもよく、ヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。）

a) A non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, wherein the non-aqueous electrolyte contains a compound represented by the following general formula (1) , Non-aqueous electrolyte. (Claim 1)

(In the above general formula (1), R ₁ represents hydrogen, halogen or an organic group having 1 to 20 carbon atoms which may have a hetero atom. R ₂ may be the same or different, In addition, they may be bonded to each other to form a ring structure and represent an organic group having 1 to 20 carbon atoms which may have hydrogen, halogen or a hetero atom, and m and n are integers of 0 or more and 5 or less . W is any group represented by the following general formula (2), R ₃ represents hydrogen, halogen or an organic group having 1 to 20 carbon atoms which may have a hetero atom, and W represents In the case of having two R _{3 s} , R _{3 s} may be the same or different from each other, or may be bonded to each other to form a ring structure.)

(X ₁ and X ₂ are any groups represented by the following general formula (3), and R's may be the same or different and each may have a hetero atom. The organic group of number 1-20 is shown.

b) The non-aqueous system according to claim 1, wherein the compound represented by the general formula (1) is a 3-butyne-1,2-diol derivative represented by the following general formula (4): Electrolytic solution. (Claim 2)

(In the general formula (4), X ₁ and X ₂ are any groups represented by the general formula (3), and R may be the same or different, An organic group having 1 to 20 carbon atoms which may have
c) The 3-butyne-1,2-diol derivative represented by the general formula (4) is at least one of the compounds represented by the following general formulas (5) to (8). The non-aqueous electrolyte solution according to claim 2. (Claim 3)

d) The nonaqueous electrolyte solution contains 0.01 to 5.0% by mass of the compound represented by the general formula (1), according to any one of claims 1 to 3. The non-aqueous electrolyte described. (Claim 4)
e) a non-aqueous electrolyte battery comprising a negative electrode and a positive electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to any one of claims 1 to 4. A non-aqueous electrolyte battery characterized by being an electrolyte. (Claim 5)
f) A compound represented by the following general formula (1). (Claim 6)

(In the above general formula (1), R ₁ represents hydrogen, halogen or an organic group having 1 to 20 carbon atoms which may have a hetero atom. R ₂ may be the same or different, In addition, they may be bonded to each other to form a ring structure and represent an organic group having 1 to 20 carbon atoms which may have hydrogen, halogen or a hetero atom, and m and n are integers of 0 or more and 5 or less . W is any group represented by the following general formula (2), and R ₃ represents hydrogen, halogen, or an organic group having 1 to 20 carbon atoms which may have a hetero atom, and W When R 2 has two R _{3 s} , R _{3 s} may be the same or different, or may be bonded to each other to form a ring structure.)

(X ₁ and X ₂ are any groups represented by the following general formula (3), and R may be the same or different and each may have a hetero atom. 1 to 20 organic groups are shown.)

  The present invention is characterized in that the compound represented by the general formula (1) is introduced into a non-aqueous electrolyte solution. Usually, as typified by Patent Documents 1 to 3, many materials that protect the electrode surface and improve battery durability such as storage characteristics and cycle characteristics often have multiple bonding sites. The present inventors paid attention to this point, and examined in detail the bonding sites of functional groups and heteroelements in the ring structure, the sites where multiple bonds are bonded to the ring structure, and the hybrid state of the electron orbits of the multiple bonds. As a result, in the non-aqueous electrolyte battery into which a series of compound groups having the structure of the compound represented by the general formula (1) is introduced, conventional chain and cyclic carbonates containing unsaturated bonds (Example 1) -2, comparative example 2-3, 5-6) battery durability improved drastically, the knowledge which can solve said subject was acquired, and it came to complete this invention.

  The reason why the battery durability characteristics can be dramatically improved as described above is not completely clear at present, but it has a reactive carbon-carbon triple bond, a carbon-carbon triple bond. The adjacent carbon is a tertiary carbon and the compound represented by the general formula (1) is included on the electrode surface due to a relatively high acidity due to a kind of resonance structure and having two ester groups. The protective coating is highly developed. Thus, it is presumed that a non-aqueous electrolyte battery having improved durability characteristics such as cycle and storage of the battery is provided by suppressing the side decomposition reaction caused by the electrolyte components other than those described above. Such a remarkable battery durability improvement effect is not confirmed by the carbon-carbon double bond compounds described in Patent Documents 1 and 2. Moreover, even if it is a compound which has a carbon-carbon triple bond as described in patent document 3, when it is not a compound structure represented by General formula (1), it should be noted as mentioned above. Since the effect is not confirmed (see, for example, Examples and Comparative Examples), it can be seen that this is a specific feature of the compound represented by the general formula (1).

  Thus, by using the present invention, particularly in the design of a lithium secondary battery with high voltage and high capacity, the non-aqueous electrolyte battery with improved durability characteristics such as cycle and storage, and the non-aqueous electrolyte can be used. The non-aqueous electrolyte used is provided.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.

The non-aqueous electrolyte secondary battery of the present invention is suitable for use as, for example, an electrolyte for a lithium secondary battery among non-aqueous electrolyte batteries. The non-aqueous electrolyte secondary battery of the present invention can adopt a known structure, and typically includes a negative electrode and a positive electrode capable of occluding and releasing ions (for example, lithium ions), an aqueous electrolyte, and a separator. Is provided.

1. Non-aqueous electrolyte The non-aqueous electrolyte of the present invention relates to a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, and contains a compound having a carbon-carbon triple bond. And

（上記一般式（１）中、Ｒ₁は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素
数１〜２０の有機基を示す。Ｒ₂はそれぞれ同一であっても異なっていても、また互いに
結合して環構造を形成していてもよく、水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。ｍ、ｎは０以上の整数である。Ｗは下記一般式（２）で表される何れか基であって、Ｒ_３は水素、ハロゲンまたはヘテロ原子を有していてもよい炭素数１〜２０の有機基を示し、Ｗが２つのＲ_３を有する場合、Ｒ_３はそれぞれ同一であっても異なっていても、また互いに結合して環構造を形成していてもよい。）

（Ｘ₁、Ｘ₂はそれぞれ下記一般式（３）で表される何れかの基であって、Ｒはそれぞれ同一であっても異なっていてもよく、ヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。）

ここで、ｍおよびｎは、式中で定められた範囲であれば特に限定されないが、好ましくは、０から５であり、さらに好ましくは０〜３、もっとも好ましくはｍかｎの何れかが０
であり、他方が１である。 1-1. Compound Represented by General Formula (1) The non-aqueous electrolyte solution of the present invention contains a compound represented by the general formula (1). If it is a compound represented by General formula (1), since it contributes to durability improvement by forming an interface protective film with an electrode suitably, it will not specifically limit.

(In the above general formula (1), R ₁ represents hydrogen, halogen or an organic group having 1 to 20 carbon atoms which may have a hetero atom. R ₂ may be the same or different, In addition, they may be bonded to each other to form a ring structure and represent an organic group having 1 to 20 carbon atoms which may have hydrogen, halogen or a hetero atom, and m and n are integers of 0 or more. W is any group represented by the following general formula (2), R ₃ represents hydrogen, halogen or an organic group having 1 to 20 carbon atoms which may have a hetero atom, and W is two If with R _3, R ₃ is also optionally substituted by one or more identical respectively, or may be bonded to form a ring structure.)

(X ₁ and X ₂ are any groups represented by the following general formula (3), and R's may be the same or different and each may have a hetero atom. The organic group of number 1-20 is shown.

Here, m and n are not particularly limited as long as they are in the range defined in the formula, but are preferably 0 to 5, more preferably 0 to 3, and most preferably either m or n is 0.
And the other is 1.

In the general formula (1), R ₁ is not particularly limited as long as it is within the range defined in the formula, but preferably hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, Examples thereof include an unsaturated aliphatic hydrocarbon group which may have a group and an aromatic hydrocarbon group which may have a substituent, and these may have a hetero atom. More preferably, it is hydrogen.
Here, a saturated aliphatic hydrocarbon group which may have a substituent, an unsaturated aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent / aromatic The substituent of the heterocyclic ring is not particularly limited, but preferably includes halogen and ester groups such as carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, and phosphorous acid, and more preferably halogen, Most preferred is fluorine.
The term “may have a heteroatom” includes, for example, a case where a part of carbon atoms in an organic group is substituted with a heteroatom, and a case where the organic group has a functional group containing a heteroatom. Means that. The following description of “may have a heteroatom” is also synonymous.

In the general formula (1), R ₂ is not particularly limited as long as it is within the range defined in the formula, but preferably has a saturated aliphatic hydrocarbon group which may have a substituent, or a substituent. Examples thereof may include an unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group which may have a substituent, and the like, and these may have a hetero atom. In addition, when R < ₂ > couple | bonds together and forms a ring structure, it means that this ring structure is a C1-C20 organic group (structure) which may have a hetero atom.
Here, a saturated aliphatic hydrocarbon group which may have a substituent, an unsaturated aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent / aromatic The substituent of the heterocyclic ring is not particularly limited, but preferably includes halogen and ester groups such as carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, and phosphorous acid, and more preferably halogen, Most preferred is fluorine.

In the general formula (2), R ₃ is not particularly limited as long as it is within the range defined in the formula, but is preferably hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, or a substituted group. Examples thereof include an unsaturated aliphatic hydrocarbon group which may have a group and an aromatic hydrocarbon group which may have a substituent, and these may have a hetero atom. More preferably, it is hydrogen. Note that when R ₃ is to "combine to form a ring structure" means that such ring structure is an organic group having 1 to 20 carbon atoms which may have a hetero atom (structure).
Here, a saturated aliphatic hydrocarbon group which may have a substituent, an unsaturated aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent / aromatic The substituent of the heterocyclic ring is not particularly limited, but preferably includes halogen and ester groups such as carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, and phosphorous acid, and more preferably halogen, Most preferred is fluorine.

In the general formula (3), R is not particularly limited as long as it is within the range defined in the formula, but may be a saturated aliphatic hydrocarbon group that may have a substituent, or a group that may have a substituent. Examples thereof include a saturated aliphatic hydrocarbon group and an aromatic hydrocarbon group which may have a substituent, and these may have a hetero atom. “R may be the same or different from each other” means that R in X ₁ and R in X ₂ may be the same or different, and further in X ₁ or if it contains two R in X ₂ is intended to mean both that the two R may be different and the same.
Here, a saturated aliphatic hydrocarbon group which may have a substituent, an unsaturated aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent / aromatic The substituent of the heterocyclic ring is not particularly limited, but preferably includes halogen and ester groups such as carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, and phosphorous acid, and more preferably halogen, Most preferred is fluorine.

Specific examples of preferable saturated aliphatic hydrocarbon groups in R _{1 to} R ₃ and R include a methyl group, an ethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl Group, 2,2,2-trifluoroethyl group, phenyl group, cyclopentyl group, cyclohexyl group, methoxycarbonyloxymethyl group, ethoxycarbonyloxymethyl group, 1- (methoxycarbonyloxy) -ethyl group, 1- (ethoxycarbonyl) Oxy) -ethyl group, 2- (methoxycarbonyloxy) -ethyl group, 2- (ethoxycarbonyloxy) -Ethyl group, 1- (methoxycarbonyloxy) -propyl group, 1- (ethoxycarbonyloxy) -propyl group, 2- (methoxycarbonyloxy) -propyl group, 2- (ethoxycarbonyloxy) -propyl group, 3- (Methoxycarbonyloxy) -propyl group, 3- (ethoxycarbonyloxy) -propyl group, methylsulfonyloxymethyl group, ethylsulfonyloxymethyl group, 1- (methylsulfonyloxy) -ethyl group, 1- (ethylsulfonyloxy) -Ethyl group, 2- (methylsulfonyloxy) ethyl group, 2- (ethylsulfonyloxy) -ethyl group, 1- (methylsulfonyloxy) -propyl group, 1- (ethylsulfonyloxy) -propyl group, 2- ( Methylsulfonyloxy) -propyl group, 2- (ethyls) Honiruokishi) - propyl, 3- (methylsulfonyloxy) - propyl, 3- (ethylsulfonyl oxy) - a propyl group.

  Preferable unsaturated aliphatic hydrocarbon groups are specifically ethenyl group, 2-fluoroethenyl group, 1-methylethenyl group, 2-propenyl group, ethynyl group, 2-propynyl group, 3-fluoro-2propynyl. Group.

  Preferred aromatic hydrocarbon groups include phenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3,5-difluorophenyl group, 2, 4,6-trifluorophenyl group.

Moreover, the molecular weight of the compound represented by the general formula (1) is preferably 50 or more and 500 or less. Within this range, it is easy to ensure the solubility of the cyclic carbonate having a carbon-carbon double bond in the non-aqueous electrolyte solution, and the effects of the present invention are sufficiently exhibited. Specific examples of these preferable compounds are shown below.

（上記一般式（４）中、Ｘ₁、Ｘ₂はそれぞれ前記一般式（３）で表される何れかの基であって、Ｒはそれぞれ同一であっても異なっていてもよく、ヘテロ原子を有していてもよい炭素数１〜２０の有機基を示す。） Among these compounds, it is more preferable to use a 3-butyne-1,2-diol derivative represented by the following general formula (4) from the viewpoint of ease of synthesis.

(In the general formula (4), X ₁ and X ₂ are any groups represented by the general formula (3), and R may be the same or different, An organic group having 1 to 20 carbon atoms which may have

  R in the general formula (3) in the 3-butyne-1,2-diol derivative represented by the general formula (4) is also the same as that in the general formula (3) in the compound represented by the general formula (1). Same as R.

Examples of preferable 3-butyne-1,2-diol derivatives represented by the general formula (4) include the following compounds.

Furthermore, it is particularly preferable to use any one of the compounds represented by the following general formulas (5) to (8) among the aforementioned 3-butyne-1,2-diol derivatives.

  Although the manufacturing method of the compound represented by General formula (1) is not specifically limited, For example, a corresponding diol compound is dissolved in a suitable solvent, and a base, such as an amine, is added and it cools appropriately. On the other hand, a necessary acid chloride or acid anhydride is added, and the reaction temperature is appropriately increased as necessary. The resulting crude product can be produced by purification by an appropriate method such as distillation, recrystallization or silica gel column chromatography.

  The compound represented by General formula (1) may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios. Moreover, it is preferable that content of the compound represented by the said General formula (1) is 0.01-5.0 mass% in nonaqueous electrolyte solution, 0.01-3.0 mass% It is more preferable that it is contained, and it is particularly preferable that it is contained in an amount of 0.01 to 2.0% by mass. When content of the compound represented by the said General formula (1) exists in the said range, the effect of this invention can be exhibited more.

1-2. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used in this application, and any lithium salt can be used.
Specific examples include the following.

For example, inorganic lithium salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiNbF ₆ , LiTaF ₆ , LiWF ₇ ;
Lithium fluorophosphates such as LiPO ₃ F and LiPO ₂ F ₂ ;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃
Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃
Sulfonic acid lithium salts such as SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂
Lithium imide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂
And fluorine-containing organic lithium salts such as (CF ₃ SO ₂ ) ₂ and LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ .

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiPO ₂ F ₂ , FSO ₃ Li, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN ( CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂
F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, lithium tris (oxalato) phosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _{3 and the} like are particularly preferable because they have the effect of improving output characteristics, high-rate charge / discharge characteristics, high-temperature storage characteristics, cycle characteristics, and the like.

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using two or more kinds in combination is a combination of LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, LiPF ₆ and LiPO ₂ F _2, etc., and has an effect of improving load characteristics and cycle characteristics. . Among these, the combined use of LiPF ₆ and FSO ₃ Li, or LiPF ₆ and LiPO ₂ F ₂ is preferable because the effect is remarkable.

When LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li are used in combination, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by mass of the entire non-aqueous electrolyte is not limited, and the effects of the present invention are not significantly impaired. As long as it is optional, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, and the upper limit is usually 30% by mass or less, preferably 20% with respect to the non-aqueous electrolyte solution of the present invention. It is below mass%. On the other hand, even when LiPF ₆ and LiPO ₂ F ₂ are used in combination, the concentration of LiPO ₂ F ₂ with respect to 100% by mass of the total amount of the non-aqueous electrolyte is not limited as long as the effect of the present invention is not significantly impaired. However, with respect to the non-aqueous electrolyte solution of the present invention, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, while its upper limit is usually 10% by mass or less, preferably 5% by mass or less. is there. Within this range, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature characteristics are improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. may be reduced.

Here, the preparation of the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, Ya separately active material method and later be added to the electrolytic solution containing LiPF ₆ and LiPO ₂ F ₂ synthesized by a known method A method of generating LiPO ₂ F ₂ in the system when water is made to coexist in a battery component such as an electrode plate and a battery is assembled using an electrolytic solution containing LiPF ₆ is included. You may use the method of.

The method for measuring the content of LiPO ₂ F ₂ in the non-aqueous electrolyte and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. Examples include ion chromatography and F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR).
Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As an organic lithium salt, CF ₃ SO ₃
Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethane Disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, Lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ Etc. are preferred. In this case, the ratio of the organic lithium salt to 100% by mass of the whole non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, preferably 30% by mass or less, particularly preferably. It is 20 mass% or less.

  The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired, but the electric conductivity of the electrolyte solution is in a good range, and good battery performance is ensured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and further preferably 0.5 mol / L or more. Preferably it is 3 mol / L or less, More preferably, it is 2.5 mol / L or less, More preferably, it is 2.0 mol / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

1-3. Solvent As the non-aqueous solvent, a saturated cyclic carbonate, a cyclic carbonate having a fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, a sulfone compound, and the like can be used.

<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms.
Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

A saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
The blending amount of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the blending amount when one kind is used alone is 5% in 100% by volume of the non-aqueous solvent. Volume% or more, more preferably 10 volume% or more. By setting this range, the decrease in electrical conductivity resulting from the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, negative electrode stability, and cycle characteristics of the non-aqueous electrolyte secondary battery are good. It becomes easy to be in a range. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

Moreover, one of the preferable combinations when using 2 or more types of saturated cyclic carbonates by arbitrary combinations is a combination to ethylene carbonate and propylene carbonate.
In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 40:60, and particularly preferably 95: 5 to 50:50. Furthermore, the amount of propylene carbonate in the whole non-aqueous solvent is 0.1% by volume or more, preferably 1% by volume or more, more preferably 2% by volume or more, and the upper limit is usually 20% by volume or less, preferably 8% by volume. % Or less, more preferably 5% by volume or less. When propylene carbonate is contained within this range, it is preferable because the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

<Cyclic carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro -5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate, 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Ji Ren carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is more preferable in terms of imparting properties and suitably forming an interface protective film.

A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
The blending amount of the fluorinated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired, but in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, more preferably 0.8%. It is 1 volume% or more, More preferably, it is 0.2 volume% or more, Preferably it is 95 volume% or less, More preferably, it is 90 volume% or less. Within this range, the non-aqueous electrolyte secondary battery tends to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in the amount of gas generated. Cheap.

  In addition, the cyclic carbonate which has a fluorine atom expresses an effective function not only as a solvent but also as an auxiliary agent described in the following 1-3. There is no clear boundary in the blending amount when used as a cyclic carbonate solvent / auxiliary having a fluorine atom, and the blending amount described in the previous paragraph can be followed as it is.

<Chain carbonate>
As a chain carbonate, a C3-C7 thing is preferable.
Specifically, as the chain carbonate having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, di-i-propyl carbonate, n-propyl-i-propyl carbonate, ethyl methyl carbonate, Methyl-n-propyl carbonate, n-butyl methyl carbonate, i-butyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, i-butyl ethyl carbonate, t-butyl ethyl carbonate, etc. Is mentioned.

  Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, di-i-propyl carbonate, n-propyl-i-propyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate are preferable, and dimethyl carbonate is particularly preferable. Diethyl carbonate and ethyl methyl carbonate.

  Further, chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated chain carbonate”) can also be suitably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

  Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.

Fluorinated ethyl methyl carbonate derivatives include (2-fluoroethyl) methyl carbonate, ethyl fluoromethyl carbonate, (2,2-difluoroethyl) methyl carbonate, (2-fluoroethyl) fluoromethyl carbonate, ethyl difluoromethyl carbonate, ( 2,2,2-trifluoroethyl) methyl carbonate, (2,
2-Difluoroethyl) fluoromethyl carbonate, (2-fluoroethyl) difluoromethyl carbonate, ethyl trifluoromethyl carbonate and the like.

Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily set to a favorable range. Become. Further, the chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte and to make the large current discharge characteristics of the non-aqueous electrolyte secondary battery in a favorable range. .

The battery performance can be remarkably improved by combining ethylene carbonate at a specific blending amount with respect to the specific chain carbonate.
For example, when dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is selected as the specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 80% by volume or less, dimethyl carbonate, ethyl methyl carbonate, or diethyl It is preferable that the blending amount of carbonate is 20% by volume or more and 90% by volume or less. By selecting such a blending amount, the low-temperature deposition temperature of the electrolyte is lowered, the viscosity of the nonaqueous electrolytic solution is also lowered to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

  It is also preferable to use two or more types of specific chain carbonates in combination. When dimethyl carbonate and ethyl methyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume or less. Particularly preferred are those in which the amount of ethyl methyl carbonate is 10% by volume or more and 80% by volume or less. When a specific chain carbonate is used in combination with dimethyl carbonate and diethyl carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume. Hereinafter, it is particularly preferable that the amount of diethyl carbonate is 10% by volume or more and 70% by volume or less. Further, when ethyl methyl carbonate and diethyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, the blending amount of ethyl methyl carbonate is 10% by volume or more, 80% Those having a volume% or less and a blending amount of diethyl carbonate of 10 vol% or more and 70 vol% or less are particularly preferable.

<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula.
Specifically, gamma butyrolactone, gamma valerolactone, gamma caprolactone,
Epsilon caprolactone and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

  The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this manner, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula.
Specifically, methyl acetate, ethyl acetate, acetate-n-propyl, acetate- i- propyl, acetate-n-butyl, acetate- i- butyl, acetate-t-butyl, methyl propionate, ethyl propionate, propion Acid-n-propyl, propionate- i- propyl, propionate-n-butyl, propionate- i- butyl, propionate-t-butyl, methyl butyrate, ethyl butyrate, butyric acid-n-propyl, butyric acid- i- propyl, methyl i- butyrate, ethyl i- butyrate, i- acid -n- propyl, etc. i- butyric -i- propyl and the like.

Among them, methyl acetate, ethyl acetate, acetate-n-propyl, acetate-n-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, propionate- i- propyl, methyl butyrate, ethyl butyrate, etc. It is preferable from the point of the improvement of the ionic conductivity by a viscosity fall.

  The compounding amount of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of chain | strand-shaped carboxylic acid ester is 60 volume% or less preferably in 100 volume% of nonaqueous solvents, More preferably, it is 50 volume% or less. By setting the upper limit in this manner, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms in which part of hydrogen may be substituted with fluorine, and a cyclic ether having 3 to 6 carbon atoms are preferable.
Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, bis (2-fluoroethyl) ether, bis (2,2-difluoroethyl) ether, bis (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,2-trifluoro Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-pro ) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n -Propyl ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) ( 2,2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-tri Fluoroethyl-n-propyl ether, (3-fluoro-n-propyl) (2,2,2-trifluoroethyl) ether, (2,2,2-trifluoroethyl) (3,3,3- Trifluoroacetic -n- propyl) ether, (2,2,3,3-tetrafluoro -n- propyl) (2,2,2-trifluoroethyl) ether, (2,2,3,3,3 pen data Fluoro-n-propyl) (2,2,2-trifluoroethyl) ether, n-propyl (1,1,2,2-tetrafluoroethyl) ether, (3-fluoro-n-propyl) (1,1 , 2,2-tetrafluoroethyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetra) Fluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (1,1,2,2-tetrafluoro) Ethyl) ether, di-n- Propyl ether, (3-fluoro-n-propyl) (n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2, 3,3-tetrafluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (n-propyl) ether, bis (3-fluoro-n-propyl) ether, (3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) Ether, (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, bis (3,3,3-trifluoro-n-propyl) ether, (2 , 2, , 3-Tetrafluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (3,3,3 -Trifluoro-n-propyl) ether, bis (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2, 3,3,3-pentafluoro-n-propyl) ether, bis (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, ethoxymethoxymethane, ( 2-fluoroethoxy) methoxymethane, methoxy (2,2,2-trifluoroethoxy) methane, methoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, Toxi (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, bis (2-fluoroethoxy) methane, (2 -Fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, bis (2,2,2-trifluoroethoxy) Methane, (1,1,2,2-tetrafluoroethoxy) (2,2,2-trifluoroethoxy) methane, bis (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, ethoxymethoxyethane , (2-fluoroethoxy) methoxyethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1, 2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ) Ethane, bis (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) Ethane, bis (2,2,2-trifluoroethoxy) ethane, (1,1,2,2-tetrafluoroethoxy) (2,2,2-trifluoroethoxy) ethane, bis (1,1,2, 2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethyl Glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.

  Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

  The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall, and when a negative electrode active material is a carbonaceous material, a chain ether with lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

  The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter sometimes abbreviated as “sulfolane” including sulfolane). As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable. Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane , 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output.

As the chain sulfone, dimethylsulfone, ethylmethylsulfone, diethylsulfone, methyl-n-propylsulfone, ethyl-n-propylsulfone, di-n-propylsulfone, i-propylmethylsulfone, isopropylethylsulfone, diisopropyl Sulfone, n-butylmethylsulfone, n-butylethylsulfone, t-butylmethylsulfone, t-butylethylsulfone, fluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, (2-fluoro) ethylmethylsulfone , (2,2-difluoroethyl) methylsulfone, trifluoroethylmethylsulfone, pentafluoroethylmethylsulfone, ethylfluoromethylsulfone, ethyldifluoromethylsulfone, Tilt trifluoromethyl sulfone, perfluoroethyl methyl sulfone, ethyl (2,2,2-trifluoroethyl) sulfone, ethyl pentafluoroethyl sulfone, bis (trifluoroethyl) sulfone, bis (perfluoroethyl) sulfone, fluoromethyl N-propylsulfone, difluoromethyl-n-propylsulfone, trifluoromethyl-n-propylsulfone, fluoromethyl-i-propylsulfone, difluoromethyl-i-propylsulfone, trifluoromethyl-i-propylsulfone, trifluoro Ethyl-n-propylsulfone, trifluoroethyl-i-propylsulfone, pentafluoroethyl-n-propylsulfone, pentafluoroethyl-i-propylsulfone, n-butyl (2,2,2-trimethyl) Ruoroechiru) Rusuruhon, t- butyl (2,2,2-trifluoroethyl) sulfone, n- butyl pentafluoroethyl sulfone, t- butyl pentafluoroethyl sulfone, and the like.

  Among them, dimethylsulfone, ethylmethylsulfone, diethylsulfone, methyl-n-propylsulfone, methyl-i-propylsulfone, methyl-n-butylsulfone, t-butylmethylsulfone, fluoromethylmethylsulfone, difluoromethylmethylsulfone, tri Fluoromethylmethylsulfone, (2-fluoroethyl) methylsulfone, (2,2-difluoroethyl) methylsulfone, methyltrifluoroethylsulfone, methylpentafluoroethylsulfone, ethylfluoromethylsulfone, difluoromethylethylsulfone, ethyltrifluoro Methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, n-propyl trifluoromethyl sulfone, i-propyl trifluoromethyl sulfone Hong, n- butyl trifluoroethyl sulfone, t- butyl trifluoroethyl sulfone, n- butyl trifluoromethylsulfonate, t- butyl trifluoromethyl sulfone is preferred because a higher high output ionic conductivity.

  The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 0.5% by volume or more, and further preferably 1% by volume or more in 100% by volume of the nonaqueous solvent. Is 40% by volume or less, more preferably 35% by volume or less, and still more preferably 30% by volume or less. Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte secondary battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.

1-4. Auxiliary agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used according to the purpose in addition to the compound having a carbon-carbon triple bond. Examples of the auxiliary agent include a cyclic carbonate having an unsaturated bond shown below, an unsaturated cyclic carbonate having a fluorine atom, an overcharge inhibitor, and other auxiliary agents.

<Cyclic carbonate having an unsaturated bond>
In the non-aqueous electrolyte of the present invention, in order to form a film on the negative electrode surface of the non-aqueous electrolyte battery and achieve a long battery life, in addition to the compound having a carbon-carbon triple bond, a carbon-carbon triple bond is used. A cyclic carbonate having an unsaturated bond excluding a compound having a bond (hereinafter sometimes abbreviated as “unsaturated cyclic carbonate”) can be used.

The unsaturated cyclic carbonate is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon double bond, and any unsaturated carbonate can be used. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.
Examples of the unsaturated cyclic carbonate include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates, and the like. It is done.

  The vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4 , 5-diallyl vinylene carbonate and the like.

  Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon double bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene Examples thereof include carbonate and 4-methyl-5-allylethylene carbonate.

  Among them, preferable unsaturated cyclic carbonates for use in combination with a compound having a carbon-carbon triple bond are vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, and 4,5-vinyl vinylene carbonate. , Allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4-methyl Since -5-allylethylene carbonate and 4-allyl-5-vinylethylene carbonate form a stable interface protective film, they are more preferably used.

  The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 80 or more, and more preferably 150 or less. The production method of the unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method.

An unsaturated cyclic carbonate may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios.
Moreover, the compounding quantity of unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The amount of the unsaturated cyclic carbonate is 100% by mass in the non-aqueous electrolyte solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. Moreover, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exhibited. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

<Fluorinated unsaturated cyclic carbonate>
As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as “fluorinated unsaturated cyclic carbonate”). The number of fluorine atoms contained in the fluorinated unsaturated cyclic carbonate is not particularly limited as long as it is 1 or more. Among them, the number of fluorine atoms is usually 6 or less, preferably 4 or less, and most preferably 1 or 2 fluorine atoms.

Examples of the fluorinated unsaturated cyclic carbonate include fluorinated vinylene carbonate derivatives, fluorinated ethylene carbonate derivatives substituted with an aromatic ring or a substituent having a carbon-carbon double bond.
Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- And vinyl vinylene carbonate.

  Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon double bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5. -Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate 4,5-diflu B-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4- Examples thereof include phenylethylene carbonate.

  Among them, particularly preferred fluorinated unsaturated cyclic carbonates for use in combination with a compound having a carbon-carbon triple bond include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-vinyl vinylene. Carbonate, 4-allyl-5-fluorovinylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene Carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallyl Since ethylene carbonate forms a stable interface protective film, it is more preferably used.

  The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the fluorinated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the fluorinated unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

A fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
Moreover, the compounding quantity of a fluorinated unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The compounding amount of the fluorinated unsaturated cyclic carbonate is usually 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, in 100% by mass of the nonaqueous electrolytic solution. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exhibited. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

<Cyclic sulfonate ester>
In the nonaqueous electrolytic solution of the present invention, it is also preferable to use a cyclic sulfonate ester. The molecular weight of the cyclic sulfonic acid ester compound is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 100 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the cyclic sulfonic acid ester compound with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the cyclic sulfonate compound is not particularly limited, and can be produced by arbitrarily selecting a known method.

In the non-aqueous electrolyte solution of the present invention, examples of the cyclic sulfonate compound that can be used include:
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-methyl-1,3-propane sultone 2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone, 1,4-butane sultone, 1-fluoro-1,4-butane sultone, 2-fluoro-1,4-butane sultone, 3, -Fluoro-1,4-butane sultone, 4-fluoro-1,4-butane sultone, 1-methyl-1,4-butane sultone, 2-methyl-1,4-butane sultone, 3-methyl-1,4-butane sultone, 4 -Methyl-1,4-butane sultone, 1,5-pentane sultone, 1-fluoro-1,5-pentane sultone, 2-fluoro-1,5 Pentane sultone, 3-fluoro-1,5-pentane sultone, 4-fluoro-1,5-pentane sultone, 5-fluoro-1,5-pentane sultone, 1-methyl-1,5-pentane sultone, 2-methyl Monosulfonic acid ester compounds such as -1,5-pentanthruton, 3-methyl-1,5-pentanthruton, 4-methyl-1,5-pentanthruton, 5-methyl-1,5-pentanthruton;
Disulfonate compounds such as methylene methane disulfonate, ethylene methane disulfonate, ethylene ethane disulfonate;
Etc.

Of these,
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1,4-butane sultone, methylenemethane disulfonate Ethylene methane disulfonate is preferable from the viewpoint of improving storage characteristics, and 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3 -Propane sultone is more preferred.

It is also preferable to use a cyclic sulfonic acid ester having a carbon-carbon double bond. Examples of the cyclic sulfonic acid ester having a carbon-carbon double bond include 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2 -Fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene-1 , 3-sultone, 3-methyl-1-propene-1,3-sultone, 1-butene-1,4-sultone, 2-butene-1,4-sultone, 3-butene-1,4-sultone, 1 -Fluoro-1-butene-1,4-sultone, 2-fluoro-1-butene-1,4-sultone, 3-fluoro-1-butene-1,4-sultone, 4-fluoro-1-butene-1 , 4-sultone, 1-methyl 1-butene-1,4-sultone, 2-methyl-1-butene-1,4-sultone, 3-methyl-1-butene-1,4-sultone, 4-methyl-1
Examples include butene-1,4-sultone.

  Of these, 1-propene-1,3-sultone, 1-butene-1,4-sultone, 2-butene-1,4-sultone, and 3-butene-1,4-sultone are more preferable.

A cyclic sulfonic acid ester compound may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
There is no restriction | limiting in the compounding quantity of the cyclic sulfonate ester compound with respect to the whole non-aqueous electrolyte solution of this invention, Although it is arbitrary unless the effect of this invention is impaired remarkably, Usually, it is 0.8 with respect to the non-aqueous electrolyte solution of this invention. 001% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Let When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

<Compound having a cyano group>
In the nonaqueous electrolytic solution of the present invention, it is also preferable to use a compound having a cyano group. Here, the compound having a cyano group is not particularly limited as long as it is a compound having a cyano group in the molecule, but a compound represented by the general formula (9) is more preferable.

（上記一般式（９）中、Ｔは、炭素原子、水素原子、窒素原子、酸素原子、硫黄原子、リン原子およびハロゲン原子からなる群から選ばれる原子で構成された有機基を表し、Ｕは置換基を有してもよい炭素数１から１０のＶ価の有機基である。Ｖは１以上の整数であり、Ｖが２以上の場合は、Ｔは互いに同一であっても異なっていてもよい。）

(In the above general formula (9), T represents an organic group composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom and a halogen atom; A V-valent organic group having 1 to 10 carbon atoms which may have a substituent, wherein V is an integer of 1 or more, and when V is 2 or more, T may be the same or different from each other. May be good.)

  The molecular weight of the compound having a cyano group is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more, more preferably 80 or more, still more preferably 100 or more, and 200 or less. If it is this range, it will be easy to ensure the solubility of the compound which has a cyano group with respect to nonaqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the compound having a cyano group is not particularly limited, and can be produced by arbitrarily selecting a known method.

Specific examples of the compound represented by the general formula (9) include, for example,
Acetonitrile, propionitrile, butyronitrile, i- butyronitrile, valeronitrile, i- valeronitrile, lauronitrile, 2-methylbutyronitrile, 2,2-dimethyl-butyronitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile , acrylonitrile, methacrylonitrile, crotononitrile, 3-methyl-crotononitrile, 2-methyl-2-butene nitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2, -Difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3'-oxydipropionitrile, 3,3 Compounds having one cyano group such as' -thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile;

Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, azeronitrile, sebaconitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, i-propylmalononitrile, t-butylmalononitrile, methylsk Sinonitrile, 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, trimethylsuccinonitrile, tetramethylsuccinonitrile, 3,3 ′-(ethylenedioxy) dipropionitrile, 3,3 ′ -A compound having two cyano groups such as (ethylenedithio) dipropionitrile;

Compounds having three cyano groups such as 1,2,3-tris (2-cyanoethoxy) propane and tris (2-cyanoethyl) amine;

Cyanate compounds such as methyl cyanate, ethyl cyanate, propyl cyanate, butyl cyanate, pentyl cyanate, hexyl cyanate, heptyl cyanate;

Methyl thiocyanate, ethyl thiocyanate, propyl thiocyanate, butyl thiocyanate, pentyl thiocyanate, hexyl thiocyanate, heptyl thiocyanate, methanesulfonyl cyanide, ethanesulfonyl cyanide, propanesulfonyl cyanide, butanesulfonyl cyanide, pentanesulfonyl cyanide, hexanesulfonyl cyanide , Heptanesulfonyl cyanide, methylsulfurocyanidate, ethylsulfurocyanidate, propylsulfurocyanidate, butylsulfurocyanidate, pentylsulfurocyanidate, hexylsulfurocyanidate, heptylsulfur Sulfur-containing compounds such as frocyanidates;

Cyanodimethylphosphine, cyanodimethylphosphine oxide, methyl cyanomethylphosphinate, methyl cyanomethylphosphinate, dimethylphosphinic acid cyanide, dimethylphosphinic acid cyanide, dimethylphosphonic acid dimethyl, cyanophosphonic acid dimethyl, methylphosphonic acid cyanomethyl, methylphosphonic acid Phosphorus-containing compounds such as cyanomethyl acid, cyanodimethyl phosphate, cyanodimethyl phosphite;
Etc.

Of these,
Acetonitrile, propionitrile, butyronitrile, i-butyronitrile, valeronitrile, i-valeronitrile, lauronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, Azeronitrile, sebaconitrile, undecandinitrile, and dodecanedinitrile are preferable from the viewpoint of improving the storage characteristics, and cyano such as malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecanedinitrile, etc. A compound having two groups is more preferred.

The compound which has a cyano group may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
The compounding amount of the compound having a cyano group with respect to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. 001% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Let When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

<Diisocyanate compound>
In the non-aqueous electrolyte solution of the present invention, it is also preferable to use a diisocyanate compound. Here, the diisocyanate compound is not particularly limited as long as it is a compound having two isocyanato groups in the molecule, but a compound represented by the following general formula (10) is preferable.

（上記一般式（１０）中、Ｘはフッ素で置換されていてもよい炭素数１〜１６の炭化水素基である）

(In the general formula (10), X is a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with fluorine)

  In the said General formula (10), X is a C1-C16 hydrocarbon group which may be substituted by the fluorine. The carbon number of X is preferably 2 or more, more preferably 3 or more, particularly preferably 4 or more, and is preferably 14 or less, more preferably 12 or less, particularly preferably 10 or less, and most preferably 8 or less. The type of X is not particularly limited as long as it is a hydrocarbon group. Any of an aliphatic chain alkylene group, an aliphatic cyclic alkylene group and an aromatic ring-containing hydrocarbon group may be used, but an aliphatic chain alkylene group or an aliphatic cyclic alkylene group is preferred.

Specific examples of the compound represented by the general formula (10) include, for example,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate; 1 -Methylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, 3-methylhexamethylene diisocyanate, 1,1-dimethylhexamethylene diisocyanate, 1,2-dimethylhexamethylene diisocyanate, 1,3-dimethylhexamethylene diisocyanate, 1,4 -Dimethylhexamethylene diisocyanate DOO, 1,5-dimethyl hexamethylene diisocyanate, 1,6-dimethyl-hexamethylene diisocyanate, 1, 2,3-trimethyl hexamethylene diisocyanate, branched alkylene diisocyanates and the like; 1,4-diisocyanato-2-butene, 1, 5-diisocyanato-2-pentene, 1,5-diisocyanato-3-pentene, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-
Diisocyanatoalkenes such as hexene, 1,8-diisocyanato-2-octene, 1,8-diisocyanato-3-octene, 1,8-diisocyanato-4-octene; 1,3-diisocyanato-2-fluoropropane 1,3-diisocyanato-2,2-difluoropropane, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2,2-difluorobutane, 1,4-diisocyanato-2,3-difluorobutane 1,6-diisocyanato-2-fluorohexane, 1,6-diisocyanato-3-fluorohexane, 1,6-diisocyanato-2,2-difluorohexane, 1,6-diisocyanato-2,3-difluorohexane, , 6-Diisocyanato-2,4-difluorohexane, 1,6-diisocyanato 2,5-difluorohexane, 1,6-diisocyanato-3,3-difluorohexane, 1,6-diisocyanato-3,4-difluorohexane, 1,8-diisocyanato-2-fluorooctane, 1,8-diisocyanato- 3-fluorooctane, 1,8-diisocyanato-4-fluorooctane, 1,8-diisocyanato-2,2-difluorooctane, 1,8-diisocyanato-2,3-difluorooctane, 1,8-diisocyanato-2, Fluorine-substituted diisocyanates such as 4-difluorooctane, 1,8-diisocyanato-2,5-difluorooctane, 1,8-diisocyanato-2,6-difluorooctane, 1,8-diisocyanato-2,7-difluorooctane Natoalkanes; 1,2-diisocyanatocyclopentane, 1, -Diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3- Bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, dicyclohexylmethane-3,3′-diisocyanate, Cycloalkane ring-containing diisocyanates such as dicyclohexylmethane-4,4′-diisocyanate; 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene-2, Diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,5-diisocyanate, tolylene-2,6-diisocyanate, tolylene-3,4-diisocyanate, tolylene-3,5-diisocyanate, 1,2-bis (isocyanate) Natomethyl) benzene, 1,3-bis (isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene, 2,4-diisocyanatobiphenyl, 2,6-diisocyanatobiphenyl, 2,2 '-Diisocyanatobiphenyl, 3,3'-diisocyanatobiphenyl, 4,4'-diisocyanato-2-methylbiphenyl, 4,4'-diisocyanato-3-methylbiphenyl, 4,4'-diisocyanato-3, 3'-dimethylbiphenyl, 4,4'-diisocyanatodiphenylmethane, 4,4'- Isocyanato-2-methyldiphenylmethane, 4,4′-diisocyanato-3-methyldiphenylmethane, 4,4′-diisocyanato-3,3′-dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 1,8-diisocyanato Aromatic rings such as naphthalene, 2,3-diisocyanatonaphthalene, 1,5-bis (isocyanatomethyl) naphthalene, 1,8-bis (isocyanatomethyl) naphthalene, 2,3-bis (isocyanatomethyl) naphthalene Containing diisocyanates;
Etc.

Among these,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate; 1 -Methylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, 3-methylhexamethylene diisocyanate, 1,1-dimethylhexamethylene diisocyanate, 1,2-dimethylhexamethylene diisocyanate, 1,3-dimethylhexamethylene diisocyanate, 1,4 -Dimethylhexamethylene diisocyanate DOO, 1,5-dimethyl hexamethylene diisocyanate, 1,6-dimethyl-hexamethylene diisocyanate, 1, 2,3-trimethyl hexamethylene diisocyanate, branched alkylene diisocyanates and the like; 1,2-diisocyanato cyclopentane, 1, 3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3 -Bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-3,3 ' Diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cycloalkane ring containing diisocyanates and the like;
Is preferred.

Moreover,
Linear polymethylene diisocyanates selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane 4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, dicyclohexylmeta 3,3'-diisocyanate, cycloalkane ring containing diisocyanates selected from dicyclohexylmethane-4,4'-diisocyanate;
Is particularly preferred.

Moreover, the diisocyanate in this invention mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
In the non-aqueous electrolyte of the present invention, when diisocyanate is used, its content is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably based on the total mass of the non-aqueous electrolyte. Is 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 5% by mass or less, preferably 4.0% by mass or less, more preferably 3.0% by mass or less, and further preferably 2% by mass. % Or less. When the content is within the above range, durability such as cycle and storage can be improved, and the effects of the present invention can be sufficiently exhibited.

<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively suppress battery explosion / ignition when the non-aqueous electrolyte secondary battery is in an overcharged state or the like. .
As an overcharge inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, Partially fluorinated products of the above aromatic compounds such as o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And a fluorine-containing anisole compound. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

  The amount of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the battery characteristics, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, Ethyl methanesulfonate, ethanesulfo Sulfur-containing compounds such as methyl acid, ethyl ethanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl- Nitrogen-containing compounds such as 2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; hydrocarbon compounds such as heptane, octane, nonane, decane and cycloheptane; Fluorinated aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene, benzotrifluoride; methyl dimethyl phosphinate, ethyl dimethyl phosphinate, ethyl diethyl phosphinate, trimethyl phosphonoformate, triethyl phosphine Noforumeto, trimethyl phosphonoacetate, triethyl phosphonoacetate, trimethyl-3-phosphono propionate, phosphorus-containing compounds such as triethyl-3-phosphono propionate. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

  Among these, ethylene sulfite, methyl fluorosulfonate, methyl methanesulfonate, methyl ethanesulfonate, ethyl methanesulfonate, busulfan, 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate), etc. This sulfur-containing compound is particularly preferable because it has a large effect of improving capacity retention characteristics and cycle characteristics after high-temperature storage.

  The blending amount of other auxiliary agents is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate. The blending amount of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

2. Separator In the non-aqueous electrolyte secondary battery of the present invention, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.

The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among these, in the present invention, polyolefin resins, other resins, glass fibers, inorganic substances, etc., which are formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention can be used as constituent components. As the shape, it is preferable to use a porous sheet excellent in liquid retention or a non-woven fabric.

  The separator used in the present invention preferably has a polyolefin-based resin as a component. Specific examples of the polyolefin resin include polyethylene resin, polypropylene resin, 1-polymethylpentene, and polyphenylene sulfide.

  Examples of polyethylene resins include low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, and copolymers based on ethylene, that is, ethylene and propylene, butene -1, pentene-1, hexene-1, heptene-1, octene-1, etc., α-olefins having 3 to 10 carbon atoms; vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, methacryl A copolymer or multi-component copolymer with one or two or more comonomers selected from unsaturated carboxylic acid esters such as methyl acrylate and ethyl methacrylate, and unsaturated compounds such as conjugated and non-conjugated dienes, or The mixed composition is mentioned. The ethylene unit content of the ethylene polymer is usually more than 50% by mass.

Among these polyethylene resins, at least one polyethylene resin selected from low density polyethylene, linear low density polyethylene, and high density polyethylene is preferable, and high density polyethylene is most preferable.
Moreover, there is no restriction | limiting in particular in the polymerization catalyst of a polyethylene-type resin, Any things, such as a Ziegler type catalyst, a Phillips type catalyst, and a Kaminsky type catalyst, may be sufficient. As a polymerization method of the polyethylene resin, there are a one-stage polymerization, a two-stage polymerization, or a multistage polymerization more than that, and any method of the polyethylene resin can be used.

The melt flow rate (MFR) of the polyethylene resin is not particularly limited, but usually the MFR is preferably 0.03 to 15 g / 10 min, and preferably 0.3 to 10 g / 10 min. preferable. If the MFR is in the above range, the back pressure of the extruder does not become too high during the molding process and the productivity is excellent. The MFR in the present invention is JIS K7210.
The measured value under the conditions of temperature 190 ° C. and load 2.16 kg.

  The production method of the polyethylene resin is not particularly limited, and is a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst represented by a Ziegler-Natta type catalyst or a metallocene catalyst. A polymerization method using a single site catalyst may be mentioned.

Next, an example of a polypropylene resin will be described. The polypropylene resin in the present invention is homopolypropylene (propylene homopolymer), or propylene and ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene. And a random copolymer or block copolymer with α-olefin. Among these, when used for a battery separator, homopolypropylene is more preferably used from the viewpoint of mechanical strength.

The polypropylene resin preferably has an isotactic pentad fraction exhibiting stereoregularity of 80 to 99%, more preferably 83 to 98%, and still more preferably 85 to 97%. use. If the isotactic pentad fraction is too low, the mechanical strength of the battery separator may decrease. On the other hand, the upper limit of the isotactic pentad fraction is defined by the upper limit that can be obtained industrially at present, but this is not the case when a more regular resin is developed in the industrial level in the future. is not. The isotactic pentad fraction is a three-dimensional structure in which five methyl groups that are side chains are located in the same direction with respect to the main chain of carbon-carbon bonds composed of arbitrary five consecutive propylene units. Or the ratio is meant. Signal assignment of the methyl group region is as follows. Zambellietatal. (Macromol. 8, 687 (1975)).

  Moreover, it is preferable that Mw / Mn which is a parameter which shows molecular weight distribution of a polypropylene resin is 1.5-10.0. More preferably, 2.0 to 8.0, and still more preferably 2.0 to 6.0 is used. This means that the smaller the Mw / Mn, the narrower the molecular weight distribution. However, if the Mw / Mn is less than 1.5, problems such as a decrease in extrusion moldability occur, and it is difficult to produce industrially. There are many cases. On the other hand, when Mw / Mn exceeds 10.0, the low molecular weight component increases, and the mechanical strength of the obtained battery separator tends to decrease. Mw / Mn is obtained by GPC (gel per emission chromatography) method.

In addition, the melt flow rate (MFR) of the polypropylene resin is not particularly limited, but usually the MFR is preferably 0.1 to 15 g / 10 minutes, and preferably 0.5 to 10 g / 10 minutes. It is more preferable. When the MFR is less than 0.1 g / 10 minutes, the melt viscosity of the resin during the molding process is high, and the productivity is lowered. On the other hand, when it exceeds 15 g / 10 minutes, practical problems such as insufficient strength of the obtained battery separator tend to occur. MFR is JIS
In accordance with K7210, measurement is performed under conditions of a temperature of 230 ° C. and a load of 2.16 kg.

  As materials for other resins and glass fiber separators, for example, aromatic polyamide, polytetrafluoroethylene, polyethersulfone, glass filter, and the like can be used in combination with the polyolefin resin. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

  Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

  As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-mentioned independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

3. Negative electrode The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. Specific examples include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like. These may be used individually by 1 type, and may be used together combining 2 or more types arbitrarily.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like.
As a carbonaceous material used as a negative electrode active material,
(1) natural graphite,
(2) a carbonaceous material obtained by heat-treating an artificial carbonaceous material and an artificial graphite material at least once in the range of 400 to 3200 ° C;
(3) a carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different crystallinities and / or has an interface in contact with the different crystalline carbonaceous materials,
(4) A carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different orientations and / or has an interface in contact with the carbonaceous materials having different orientations,
Is preferably a good balance between initial irreversible capacity and high current density charge / discharge characteristics. Moreover, the carbonaceous materials (1) to (4) may be used alone or in combination of two or more in any combination and ratio.

  Examples of the artificial carbonaceous material and artificial graphite material of (2) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, those obtained by oxidizing these pitches, needle coke, pitch coke and Carbon materials that are partially graphitized, furnace black, acetylene black, organic pyrolysis products such as pitch-based carbon fibers, carbonizable organic materials and their carbides, or carbonizable organic materials are benzene, toluene, xylene, quinoline And a solution dissolved in a low-molecular organic solvent such as n-hexane, and carbides thereof.

  As an alloy material used as the negative electrode active material, as long as lithium can be occluded / released, lithium alone, simple metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides thereof Any of compounds such as products or phosphides may be used and is not particularly limited. The single metal and alloy forming the lithium alloy are preferably materials containing group 13 and group 14 metal / metalloid elements (that is, excluding carbon), more preferably aluminum, silicon and tin (hereinafter referred to as “ Simple metals) and alloys or compounds containing these atoms (sometimes abbreviated as “specific metal elements”). These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

As a negative electrode active material having at least one kind of atom selected from a specific metal element, a metal simple substance of any one specific metal element, an alloy composed of two or more specific metal elements, one type or two or more specific types Alloys comprising metal elements and one or more other metal elements, as well as compounds containing one or more specific metal elements, and oxides, carbides, nitrides and silicides of the compounds And composite compounds such as sulfides or phosphides. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

  In addition, a compound in which these complex compounds are complexly bonded to several kinds of elements such as a simple metal, an alloy, or a nonmetallic element is also included. Specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. For example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element may be used. it can.

  Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one simple metal of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element In particular, silicon and / or tin metal simple substance, alloy, oxide, carbide, nitride and the like are preferable from the viewpoint of capacity per unit mass and environmental load.

  The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium, but a material containing titanium and lithium is preferable from the viewpoint of high current density charge / discharge characteristics, A lithium-containing composite metal oxide material containing titanium is more preferable, and a composite oxide of lithium and titanium (hereinafter sometimes abbreviated as “lithium titanium composite oxide”). That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for a non-aqueous electrolyte battery because the output resistance is greatly reduced.

In addition, lithium or titanium of the lithium titanium composite oxide is at least selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. Those substituted with one element are also preferred.
The metal oxide is a lithium titanium composite oxide represented by the general formula (A). In the general formula (A), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, It is preferable that 0 ≦ z ≦ 1.6 because the structure upon doping and dedoping of lithium ions is stable.

Li _x Ti _y M _z O ₄ (A)
[In general formula (A), M represents at least one element selected from the group consisting of Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. ]
Among the compositions represented by the general formula (A),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
This structure is particularly preferable because of a good balance of battery performance.

Particularly preferred representative compositions of the above compounds are Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), Li _4/5 Ti _11/5 O in (c). ₄ . As for the structure of Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferable.

<Physical properties of carbonaceous materials>
When using a carbonaceous material as a negative electrode active material, it is desirable to have the following physical properties.
(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method of carbonaceous materials is preferably 0.335 nm or more, and is usually 0.360 nm or less. 350 nm or less is preferable, and 0.345 nm or less is more preferable. Further, the crystallite size (Lc) of the carbonaceous material obtained by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more, and more preferably 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) obtained by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and 7 μm. The above is particularly preferable, and is usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 25 μm or less.

If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, an uneven coating surface tends to be formed, which may be undesirable in the battery production process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20-mer) sorbitan monolaurate, which is a surfactant, and using a laser diffraction / scattering method. This is performed using a particle size distribution meter (LA-700, manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(Raman R value, Raman half width)
The Raman R value of the carbonaceous material is a value measured using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

  When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge / discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. In particular, when the Raman R value is 0.1 or more, a suitable film can be formed on the surface of the negative electrode, whereby storage characteristics, cycle characteristics, and load characteristics can be improved.

On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.
Further, the Raman half-width in the vicinity of 1580 cm ^{−1 of the} carbonaceous material is not particularly limited, but is usually 10 cm ⁻¹ or more, preferably 15 cm ⁻¹ or more, and usually 100 cm ⁻¹ or less, and 80 cm ⁻¹ or less. Preferably, it is more preferably 60 cm ⁻¹ or less, particularly preferably 40 cm ⁻¹ or less.

  If the Raman half width is less than the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge and discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

The measurement of the Raman spectrum, using a Raman spectrometer (manufactured by JASCO Corporation Raman spectrometer), the sample is naturally dropped into the measurement cell and filled, and while irradiating the sample surface in the cell with argon ion laser light, This is done by rotating the cell in a plane perpendicular to the laser beam. The resulting Raman spectrum, the intensity I _A of the peak P _A in the vicinity of 1580 cm ^-1, and measuring the intensity I _B of a peak P _B in the vicinity of 1360 cm ^-1, the intensity ratio _{R (R = I B / I} A) Is calculated. The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the carbonaceous material of the present invention.

Moreover, said Raman measurement conditions are as follows.
Argon ion laser wavelength: 514.5nm
・ Laser power on the sample: 15-25mW
・ Resolution: 10-20cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
・ Raman R value, Raman half width analysis: Background processing ・ Smoothing processing: Simple average, 5 points of convolution

(BET specific surface area)
BET specific surface area of the carbonaceous material is a value of the measured specific surface area using the BET method is usually 0.1 m ² · g ^-1 or more, 0.7 m ² · g ^-1 or more, 1. 0 m ² · g ^-1 or more, and particularly preferably 1.5 m ² · g ^-1 or more, generally not more than 100 m ² · g ^-1, preferably 25 m ² · g ^-1 or less, 15 m ² · g ⁻¹ or less is more preferable, and 10 m ² · g ⁻¹ or less is particularly preferable.
When the value of the BET specific surface area is less than this range, the acceptability of lithium is likely to deteriorate during charging when used as a negative electrode material, lithium is likely to precipitate on the electrode surface, and stability may be reduced. On the other hand, if it exceeds this range, when used as a negative electrode material, the reactivity with the non-aqueous electrolyte increases, gas generation tends to increase, and a preferable battery may be difficult to obtain.

  The specific surface area was measured by the BET method using a surface area meter (a fully automated surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 350 ° C. for 15 minutes under nitrogen flow, Using a nitrogen helium mixed gas accurately adjusted so that the value of the relative pressure becomes 0.3, the nitrogen adsorption BET one-point method by the gas flow method is used. The specific surface area determined by the measurement is defined as the BET specific surface area of the carbonaceous material of the present invention.

(Roundness)
When the circularity is measured as the degree of the sphere of the carbonaceous material, it is preferably within the following range. The circularity is defined as “circularity = (peripheral length of an equivalent circle having the same area as the particle projection shape) / (actual perimeter of the particle projection shape)”, and is theoretical when the circularity is 1. Become a true sphere.
The circularity of the particles having a particle size of 3 to 40 μm in the range of the carbonaceous material is desirably closer to 1, and is preferably 0.1 or more, more preferably 0.5 or more, and more preferably 0.8 or more, 0.85 or more is more preferable, and 0.9 or more is particularly preferable. High current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material is lowered, the resistance between particles is increased, and the high current density charge / discharge characteristics may be lowered for a short time.

  The circularity is measured using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample was dispersed in a 0.2% by mass aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate as a surfactant, and irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. The detection range is specified as 0.6 to 400 μm, and the particle size is measured in the range of 3 to 40 μm. The circularity determined by the measurement is defined as the circularity of the carbonaceous material of the present invention.

The method for improving the circularity is not particularly limited, but a sphere-shaped sphere is preferable because the shape of the interparticle void when the electrode body is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, a mechanical / physical processing method of granulating a plurality of fine particles by the binder or the adhesive force of the particles themselves, etc. Is mentioned.

(Tap density)
The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, preferably 0.5 g · cm ⁻³ or more, more preferably 0.7 g · cm ⁻³ or more, and 1 g · cm ⁻³ or more. particularly preferred, and is preferably 2 g · cm ^-3 or less, more preferably 1.8 g · cm ^-3 or less, 1.6 g · cm ^-3 or less are particularly preferred. When the tap density is below the above range, the packing density is difficult to increase when used as a negative electrode, and a high-capacity battery may not be obtained. On the other hand, when the above range is exceeded, there are too few voids between particles in the electrode, it is difficult to ensure conductivity between the particles, and it may be difficult to obtain preferable battery characteristics.

The tap density is measured by passing a sieve having a mesh opening of 300 μm, dropping the sample onto a 20 cm ³ tapping cell and filling the sample to the upper end surface of the cell, and then measuring a powder density measuring instrument (for example, manufactured by Seishin Enterprise Co., Ltd.). Using a tap denser, tapping with a stroke length of 10 mm is performed 1000 times, and the tap density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the carbonaceous material of the present invention.

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high-density charge / discharge characteristics may deteriorate. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. Set the molded body obtained by filling 0.47 g of the sample into a molding machine with a diameter of 17 mm and compressing it with 58.8 MN · m ^{-2 so} that it is flush with the surface of the sample holder for measurement. X-ray diffraction is measured. From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated. The orientation ratio calculated by the measurement is defined as the orientation ratio of the carbonaceous material of the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(Aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more and usually 10 or less, preferably 8 or less, and more preferably 5 or less. If the aspect ratio exceeds the above range, streaking or a uniform coated surface cannot be obtained when forming an electrode plate, and the high current density charge / discharge characteristics may deteriorate. The lower limit of the above range is the theoretical lower limit value of the aspect ratio of the carbonaceous material.
The aspect ratio is measured by magnifying and observing the carbonaceous material particles with a scanning electron microscope. Carbonaceous material particles when three-dimensional observation is performed by selecting arbitrary 50 graphite particles fixed to the end face of a metal having a thickness of 50 μm or less and rotating and tilting the stage on which the sample is fixed. The longest diameter A and the shortest diameter B orthogonal thereto are measured, and the average value of A / B is obtained. The aspect ratio (A / B) obtained by the measurement is defined as the aspect ratio of the carbonaceous material of the present invention.

<Configuration and production method of negative electrode>
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.
In the case of using an alloy-based material, a method of forming a thin film layer (negative electrode active material layer) containing the above-described negative electrode active material by a technique such as vapor deposition, sputtering, or plating is also used.

(Current collector)
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable from the viewpoint of ease of processing and cost.

In addition, the shape of the current collector includes, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, etc. Among them, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable, and both can be used as a current collector.
The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.

(Thickness ratio between current collector and negative electrode active material layer)
The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(the thickness of the negative electrode active material layer on one side immediately before the nonaqueous electrolyte injection) / (thickness of the current collector)” However, 150 or less is preferable, 20 or less is more preferable, 10 or less is particularly preferable, 0.1 or more is preferable, 0.4 or more is more preferable, and 1 or more is particularly preferable. When the ratio of the thickness of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge / discharge. On the other hand, below the above range, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity may decrease.

(Binder)
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used in manufacturing the electrode.
Specific examples include resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, Rubber polymers such as NBR (acrylonitrile / butadiene rubber) and ethylene / propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / Thermoplastic elastomeric polymers such as ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate , Soft resinous polymers such as ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, etc. And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass. The following is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder with respect to a negative electrode active material exceeds the said range, the binder ratio from which the amount of binders does not contribute to battery capacity may increase, and the fall of battery capacity may be caused. On the other hand, below the above range, the strength of the negative electrode may be reduced.

  In particular, when a rubbery polymer typified by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 .6% by mass or more is more preferable, and is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the main component contains a fluorine-based polymer typified by polyvinylidene fluoride, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

(Slurry forming solvent)
The solvent for forming the slurry is not particularly limited as long as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Alternatively, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N- Examples include dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, and the like.
In particular, when an aqueous solvent is used, it is preferable to add a dispersant or the like in addition to the thickener and slurry it using a latex such as SBR. In addition, these solvents may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio.

(Thickener)
A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  Further, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is more preferable. When the ratio of the thickener to the negative electrode active material is less than the above range, applicability may be significantly reduced. Moreover, when it exceeds the said range, the ratio of the negative electrode active material which occupies for a negative electrode active material layer will fall, and the problem that the capacity | capacitance of a battery falls and the resistance between negative electrode active materials may increase.

(Electrode density)
The electrode structure when the negative electrode active material is converted into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · cm ^-3 or more, preferably 2.2 g · cm ^-3 or less, more preferably 2.1 g · cm ^-3 or less, 2.0 g · cm ^-3 or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, if the amount is less than the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

(Thickness of negative electrode plate)
The thickness of the negative electrode plate is designed according to the positive electrode plate to be used, and is not particularly limited. However, the thickness of the composite layer obtained by subtracting the thickness of the metal foil of the core is usually 15 μm or more, preferably 20 μm or more. More preferably, it is 30 μm or more, and usually 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

(Surface coating of negative electrode plate)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

4). Positive electrode <positive electrode active material>
The positive electrode active material used for the positive electrode is described below.
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

The transition metal of the lithium transition metal composite oxide is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu or the like, and specific examples include lithium / cobalt composite oxide such as LiCoO ₂ or LiNiO ₂ . Lithium / nickel composite oxide, LiMnO ₂ , LiMn ₂ O ₄
, Li ₂ MnO _{4 and} other lithium-manganese composite oxides, and some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Na, K, B, F, Al, Ti, V, Cr, Mn , Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W, and the like. Specific examples of the substituted ones include, for example, LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.45 Co _0.10 Al _0.45 O ₂ , LiMn _1.8 Al _0.2 O ₄ , LiMn _1.5 Ni _0.5 O _{4 and the} like.

As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable, and specific examples include, for example, LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ). ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al, Ti, V, Cr, Mn , Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si and the like substituted with other elements.

In addition, it is preferable to include lithium phosphate in the positive electrode active material because continuous charge characteristics are improved. Although there is no restriction | limiting in the use of lithium phosphate, It is preferable to mix and use the said positive electrode active material and lithium phosphate. The lower limit of the amount of lithium phosphate used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.5% by mass with respect to the total of the positive electrode active material and lithium phosphate. %, And the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less.

(Surface coating)
Moreover, you may use what the substance of the composition different from this adhered to the surface of the said positive electrode active material. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

  For example, these surface adhering substances are dissolved or suspended in a solvent, impregnated and added to the positive electrode active material, and dried. After the surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, It can be made to adhere to the surface of the positive electrode active material by a method of reacting by heating or the like, a method of adding to the positive electrode active material precursor and firing simultaneously. In addition, when making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

The amount of the surface adhering substance is by mass with respect to the positive electrode active material, preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit, preferably 20% or less, more preferably, as the lower limit. Is used at 10% or less, more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material, and can improve the battery life. If it is too high, the resistance may increase in order to inhibit the entry and exit of lithium ions.
In the present invention, the “positive electrode active material” includes a material having a composition different from the surface attached to the surface of the positive electrode active material.

(shape)
Examples of the shape of the particles of the positive electrode active material include a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, and a column shape as conventionally used. Moreover, primary particles may aggregate to form secondary particles.

(Tap density)
The tap density of the positive electrode active material is preferably 0.5 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, and further preferably 1.0 g / cm ³ or more. If the tap density of the positive electrode active material is lower than the lower limit, the amount of the required dispersion medium increases when the positive electrode active material layer is formed, and the necessary amount of conductive material and binder increases, so that the positive electrode to the positive electrode active material layer The filling rate of the active material is restricted, and the battery capacity may be restricted. By using a complex oxide powder having a high tap density, a high-density positive electrode active material layer can be formed. In general, the tap density is preferably as large as possible, and there is no particular upper limit, but if it is too large, diffusion of lithium ions using the electrolytic solution in the positive electrode active material layer as a medium is rate-limiting, and load characteristics may be easily reduced. The upper limit is preferably 4.0 g / cm ³ or less, more preferably 3.7 g / cm ³ or less, and still more preferably 3.5 g / cm ³ or less.
In the present invention, the tap density is defined as the powder packing density (tap density) g / cc when 5 to 10 g of the positive electrode active material powder is put in a 10 ml glass measuring cylinder and tapped 200 times with a stroke of about 20 mm. Ask.

(Median diameter d ₅₀ )
The median diameter d ₅₀ of the positive electrode active material particles (secondary particle diameter when the primary particles are aggregated to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, The upper limit is preferably 30 μm or less, more preferably 27 μm or less, still more preferably 25 μm or less, and most preferably 22 μm or less. If the lower limit is not reached, a high tap density product may not be obtained. If the upper limit is exceeded, it takes time to diffuse lithium in the particles, so that the battery performance may be lowered, or the positive electrode of the battery, that is, the active material When a conductive material, a binder, or the like is slurried with a solvent and applied as a thin film, problems such as streaking may occur. Here, by mixing two or more kinds of the positive electrode active materials having different median diameters d ₅₀ , the filling property at the time of forming the positive electrode can be further improved.
In the present invention, the median diameter d ₅₀ is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When LA-920 manufactured by HORIBA is used as a particle size distribution meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersion medium for measurement, and a measurement refractive index of 1.24 is set after ultrasonic dispersion for 5 minutes. Measured.

(Average primary particle size)
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.8 μm. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If the above upper limit is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder filling property, or the specific surface area is greatly reduced, so that there is a high possibility that battery performance such as output characteristics will deteriorate. is there. On the other hand, when the value falls below the lower limit, there is a case where problems such as inferior reversibility of charge / discharge are usually caused because crystals are not developed.
In the present invention, the primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average value. It is done.

(BET specific surface area)
The BET specific surface area of the positive electrode active material is preferably 0.1 m ² / g or more, more preferably 0.2 m ² / g or more, still more preferably 0.3 m ² / g or more, and the upper limit is 50 m ² / g or less. , Preferably 40 m ² / g or less, more preferably 30 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance tends to be lowered. If the BET specific surface area is larger, the tap density is difficult to increase, and a problem may occur in applicability when forming the positive electrode active material layer.
In the present invention, the BET specific surface area is determined by using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 150 ° C. for 30 minutes under nitrogen flow, and then atmospheric pressure. This is defined as a value measured by a nitrogen adsorption BET one-point method using a gas flow method, using a nitrogen-helium mixed gas accurately adjusted so that the value of the relative pressure of nitrogen to 0.3 is 0.3.

(Method for producing positive electrode active material)
As a manufacturing method of the positive electrode active material, a general method is used as a manufacturing method of the inorganic compound. In particular, various methods are conceivable for preparing a spherical or elliptical active material. For example, a transition metal source material is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring. And a spherical precursor is prepared and recovered, and after drying as necessary, a Li source such as LiOH, Li ₂ CO ₃ , LiNO _{3 and the} like is added and fired at a high temperature to obtain an active material. .

For the production of the positive electrode, the positive electrode active material may be used alone, or one or more of different compositions may be used in any combination or ratio. A preferable combination in this case is a combination of LiCoO ₂ and LiMn ₂ O ₄ such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂ or a part of this Mn substituted with another transition metal or the like, or LiCoO ₂ or The combination with what substituted a part of Co with other transition metals etc. is mentioned.

<Configuration and manufacturing method of positive electrode>
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. Manufacture of the positive electrode using a positive electrode active material can be performed by a conventional method. That is, a positive electrode active material and a binder, and if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

  The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Moreover, an upper limit becomes like this. Preferably it is 99 mass% or less, More preferably, it is 98 mass% or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more as a lower limit, more preferably 2 g / cm ³ , further preferably 2.2 g / cm ³ or more, and preferably 5 g / cm ³ as an upper limit. ^{It is 3} or less, more preferably 4.5 g / cm ³ or less, and further preferably 4 g / cm ³ or less. If it exceeds this range, the permeability of the electrolyte solution to the vicinity of the current collector / active material interface decreases, and the charge / discharge characteristics particularly at a high current density decrease, and a high output may not be obtained. On the other hand, if it is lower, the conductivity between the active materials is lowered, the battery resistance is increased, and high output may not be obtained.

(Conductive material)
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more in the positive electrode active material layer, and the upper limit is usually 50% by mass or less, preferably It is used so as to contain 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

(Binder)
The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of the coating method, any material that can be dissolved or dispersed in the liquid medium used during electrode production may be used. Resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, isoprene rubber , Rubber polymers such as butadiene rubber and ethylene-propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / Ethylene copolymer, styrene Thermoplastic elastomeric polymer such as isoprene / styrene block copolymer or hydrogenated product thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer Soft resinous polymers such as polymers; Fluoropolymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers; alkali metal ions (especially lithium ions) And a polymer composition having ion conductivity. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and the upper limit is usually 80% by mass or less, preferably Is 60% by mass or less, more preferably 40% by mass or less, and most preferably 10% by mass or less. When the ratio of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, battery capacity and conductivity may be reduced.

(Slurry forming solvent)
As the solvent for forming the slurry, the positive electrode active material, the conductive material, the binder, and a solvent capable of dissolving or dispersing the thickener used as necessary may be used. There is no restriction, and either an aqueous solvent or an organic solvent may be used. Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N, N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) Amides such as dimethylformamide and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide.

  In particular, when an aqueous medium is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios. When a thickener is further added, the ratio of the thickener to the active material is 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more. The upper limit is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. Below this range, applicability may be significantly reduced. If it exceeds, the ratio of the active material in the positive electrode active material layer may decrease, and there may be a problem that the capacity of the battery decreases and a problem that the resistance between the positive electrode active materials increases.

(Current collector)
The material of the positive electrode current collector is not particularly limited, and a known material can be arbitrarily used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum, are preferred.

Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. Although the thickness of the thin film is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the thin film is thinner than this range, the strength required for the current collector may be insufficient. Conversely, if the thin film is thicker than this range, the handleability may be impaired.

Moreover, it is also preferable from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer that a conductive additive is applied to the surface of the current collector. Examples of the conductive assistant include noble metals such as carbon, gold, platinum, and silver.
The ratio of the thickness of the current collector to the positive electrode active material layer is not particularly limited, but the value of (thickness of the positive electrode active material layer on one side immediately before electrolyte injection) / (thickness of the current collector) is 20 The lower limit is preferably 15 or less, most preferably 10 or less, and the lower limit is preferably 0.5 or more, more preferably 0.8 or more, and most preferably 1 or more. Above this range, the current collector may generate heat due to Joule heat during high current density charge / discharge. Below this range, the volume ratio of the current collector to the positive electrode active material increases and the battery capacity may decrease.

(Electrode area)
When using the non-aqueous electrolyte of the present invention, it is preferable that the area of the positive electrode active material layer is larger than the outer surface area of the battery outer case from the viewpoint of increasing the stability at high output and high temperature. Specifically, the sum of the electrode areas of the positive electrode with respect to the surface area of the exterior of the secondary battery is preferably 15 times or more, and more preferably 40 times or more. The outer surface area of the outer case is the total area obtained by calculation from the vertical, horizontal, and thickness dimensions of the case part filled with the power generation element excluding the protruding part of the terminal in the case of a bottomed square shape. . In the case of a bottomed cylindrical shape, the geometric surface area approximates the case portion filled with the power generation element excluding the protruding portion of the terminal as a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode mixture layer facing the mixture layer containing the negative electrode active material, and in the structure in which the positive electrode mixture layer is formed on both sides via the current collector foil. , The sum of the areas where each surface is calculated separately.

(Thickness of positive plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the composite layer obtained by subtracting the metal foil thickness of the core material is preferably as a lower limit with respect to one side of the current collector. Is 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Positive electrode surface coating)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said positive electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

5. Battery design <electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less. .

  When the electrode group occupancy is below the above range, the battery capacity decreases. In addition, if the above range is exceeded, there is less void space, the battery expands, and the member expands or the vapor pressure of the liquid component of the electrolyte increases and the internal pressure rises, and the charge / discharge cycle performance as a battery In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Current collection structure>
The current collecting structure is not particularly limited, but in order to more effectively realize the high current density charge / discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure that reduces the resistance of the wiring part and the joint part is used. It is preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

  When the electrode group has the above-described laminated structure, a structure formed by bundling the metal core portions of the electrode layers and welding them to the terminals is preferably used. When the area of one electrode increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the winding structure described above, the internal resistance can be lowered by providing a plurality of lead structures for the positive electrode and the negative electrode, respectively, and bundling the terminals.

<Exterior case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

  In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.

<Protective element>
As a protective element, PTC (Positive Temperature Coefficient) whose resistance increases when abnormal heat generation or excessive current flows, temperature fuse, thermistor, shuts off the current flowing through the circuit due to sudden increase in battery internal pressure or internal temperature at abnormal heat generation A valve (current cutoff valve) or the like can be used. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

<Exterior body>
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

6). Battery Performance The non-aqueous electrolyte secondary battery of the present invention can be used without particular limitation, but can be preferably used for a battery having a high voltage or a high capacity.

For example, in the case of a lithium ion secondary battery, the increase in voltage is usually 4.25 V or more, preferably 4.3 or more.
The increase in capacity is usually 2600 mAh or more, preferably 2800 mAh or more, more preferably 3000 mAh or more in the case of an 18650 type battery, for example.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

窒素気流下、ジクロロメタンに文献記載の方法で得られる１，２−ジヒドロキシ−３−ブチン（非特許文献１）を溶解し、ピリジンを添加して撹拌した。氷冷下でクロロギ酸メチルを滴下した。４時間撹拌後、水を加えて反応を停止し、室温で一晩静置した。この反応終了液をジクロロメタンで５回抽出し、混合した有機層を希塩酸、水、重曹水、水、食塩水で順次洗浄し、無水硫酸ナトリウムで乾燥した。減圧条件で溶媒を留去し、得られた残渣を減圧蒸留(３ｍｍＨｇ、沸点：１０４℃)にて精製し、無色油状の化合物Ｉを得た。 [Synthesis of Compound Represented by General Formula (1)]
[Synthesis of 3-ethynyl-2,5-dioxahexanedioic acid dimethyl (EDOHM)]

Under a nitrogen stream, 1,2-dihydroxy-3-butyne (Non-patent Document 1) obtained by the method described in the literature was dissolved in dichloromethane, and pyridine was added and stirred. Methyl chloroformate was added dropwise under ice cooling. After stirring for 4 hours, water was added to stop the reaction, and the mixture was allowed to stand at room temperature overnight. This reaction-terminated liquid was extracted five times with dichloromethane, and the combined organic layer was washed successively with dilute hydrochloric acid, water, aqueous sodium bicarbonate, water and brine, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified by distillation under reduced pressure (3 mmH g , boiling point: 104 ° C.) to obtain Compound I as a colorless oil.

[Example A]
[Production of negative electrode]
98 parts by mass of a carbonaceous material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of carboxymethylcellulose sodium) and an aqueous dispersion of styrene-butadiene rubber (styrene-butadiene, respectively) as a thickener and a binder 1 part by mass of rubber concentration 50 mass%) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 10 μm, dried, and rolled with a press. The active material layer was 30 mm wide, 40 mm long, 5 mm wide, and 9 mm long uncoated. It cut out into the shape which has a part, and it was set as the negative electrode used for Example 1 and Comparative Examples 1-3, respectively.

[Production of positive electrode]
90% by mass of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder Were slurried by mixing in N-methylpyrrolidone solvent. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press. The active material layer was 30 mm in width, 40 mm in length, 5 mm in width, and 9 mm in length. It cut out into the shape which has a process part, and it was set as the positive electrode used for Example 1 and Comparative Examples 1-3, respectively.

[Manufacture of electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a mixture (volume ratio 30:30:40) of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) was adjusted to a ratio of 1 mol / L. A basic electrolyte solution was prepared by dissolution. The basic electrolyte solution was mixed with the compounds described in Table 2 to obtain electrolyte solutions used in Example 1 and Comparative Examples 1 to 3, respectively.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and then an electrolytic solution in which the compounds shown in Table 2 were mixed Each was injected into a bag, vacuum-sealed, and a sheet-like battery was produced, and batteries used in Example 1 and Comparative Examples 1 to 3 were obtained.

[Run-in operation]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 2C represents a current value that is twice that, and 0.2C represents a current value that is 1/5 of the current value.

[Evaluation of cycle characteristics]
The battery that had been subjected to the running-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C. The discharge capacity retention rate was determined from the formula of (discharge capacity at 500th cycle) ÷ (discharge capacity at the first cycle) × 100. The evaluation results are shown in Table 2.

[Example B]
[Production of negative electrode]
A negative electrode used in Example 2 and Comparative Examples 4 to 6 was prepared in the same manner as the negative electrode used in Example 1 and Comparative Examples 1 to 3, respectively.

[Production of positive electrode]
90% by mass of Li (Ni _0.45 Mn _0.45 Co _0.1 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder, -Mixed in a methylpyrrolidone solvent and slurried. The obtained slurry was applied to a 15 μm-thick aluminum foil previously coated with a conductive additive, dried, and rolled with a press machine. The active material layer size was 30 mm wide, 40 mm long, and 5 mm wide. The positive electrode used in Example 2 and Comparative Examples 4 to 6 was cut into a shape having an uncoated part with a length of 9 mm.

[Manufacture of electrolyte]
The basic electrolytes used in Example 1 and Comparative Examples 1 to 3 were mixed with the compounds shown in Table 3 to obtain electrolytes used in Example 2 and Comparative Examples 4 to 6, respectively.

[Manufacture of lithium secondary batteries]
Except using the said negative electrode, a positive electrode, and the said electrolyte solution, the sheet-like battery was produced like Example 1 and Comparative Examples 1-3, and it was set as the battery used for Example 2 and Comparative Examples 4-6, respectively.

[Run-in operation]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes.

[Evaluation of cycle characteristics]
The battery that had been subjected to the running-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C, and 300 cycles were performed. The discharge capacity retention ratio was calculated from the formula of (discharge capacity at 300th cycle) ÷ (discharge capacity at the first cycle) × 100. The evaluation results are shown in Table 3.

  As is clear from Tables 2 and 3, the nonaqueous electrolyte batteries (Examples 1 and 2) according to the present invention are excellent in discharge capacity retention rate. Such a high discharge capacity retention rate is attributed to the structure of the compound represented by the general formula (1). For example, in the case of having a carbon-carbon triple bond as in Examples 1 and 2. Even if it is not the structure of the compound represented by the general formula (1), the capacity retention rate is low (Comparative Example 3 and Comparative Example 6). Moreover, even if it uses ethylene diol dicarbonate which the carbon-carbon unsaturated bond has not couple | bonded, it will be a result with a low capacity | capacitance maintenance factor (comparative example 2). The above facts show that the structure of the compound represented by the general formula (1) is extremely important, and the compound represented by the general formula (1) has a highly reactive carbon-carbon triple bond. The carbon adjacent to the carbon-carbon triple bond is a tertiary carbon, has a relatively high acidity due to a kind of resonance structure, and has two ester groups. The protective coating containing the compound represented by) is highly developed. Thus, it is presumed that a non-aqueous electrolyte battery having improved durability characteristics such as cycle and storage of the battery is provided by suppressing the side decomposition reaction caused by the electrolyte components other than those described above.

  The non-aqueous electrolyte solution of the present invention is extremely useful because the durability characteristics of the non-aqueous electrolyte secondary battery can be improved to a high degree. Therefore, the non-aqueous electrolyte solution of the present invention and the non-non-aqueous electrolyte secondary battery using the same can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Load Examples include leveling power sources and natural energy storage power sources.

Claims (5)

A non-aqueous electrolyte solution comprising a lithium salt and a non-aqueous solvent for dissolving the lithium salt, wherein the non-aqueous electrolyte solution is a 3-butyne-1,2-diol derivative represented by the following general formula ( 4 ) A non-aqueous electrolyte solution characterized by being.

(In the above general formula ( 4 ), X ₁ and X ₂ are any groups represented by the following general formula, and each R may be the same or different and has a heteroatom. An organic group having 1 to 20 carbon atoms which may be present.

The 3-butyne-1,2-diol derivative represented by the general formula (4) is at least one of the compounds represented by the following general formulas (5) to (8). The non-aqueous electrolyte solution according to claim 1 .

The non-aqueous electrolyte solution according to claim 1 or 2 , wherein the non-aqueous electrolyte solution contains 0.01 to 5.0 mass% of the compound represented by the general formula ( 4 ). Negative and positive lithium ions capable of occluding and releasing, as well as non-aqueous electrolyte A nonaqueous electrolyte battery comprising a nonaqueous electrolytic solution according to any one of the nonaqueous electrolytic solution according to claim 1 to 3 A non-aqueous electrolyte battery characterized by the above. The compound represented by the following general formula ( 4 ).

(In the above general formula ( 4 ), X ₁ and X ₂ are any groups represented by the following general formula, and each R may be the same or different and has a heteroatom. An organic group having 1 to 20 carbon atoms which may be present.