JP2008091327A - Nonaqueous electrolyte battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress gas occurrence of a nonaqueous electrolyte battery, especially gas occurrence in high temperature storage to suppress the swelling of the nonaqueous electrolyte battery. <P>SOLUTION: The nonaqueous electrolyte battery is equipped with a nonaqueous electrolyte, a positive electrode, and a negative electrode having a negative active material inserting or releasing lithium ions at a potential of 1.2 V or higher vs. Li. The nonaqueous electrolyte contains vinylene carbonate, the negative electrode has a coating thereon, and the battery is used in a region of a negative electrode potential nobler than 0.8 V vs. Li. The manufacturing method of the nonaqueous electrolyte battery is such that the nonaqueous electrolyte containing vinylene carbonate is used, the initial charge discharge is conducted in a condition that the negative electrode potential in a charging completion stage exceeds 0.8 V vs. Li to form the coating on the surface of the negative electrode, or in the initial charge discharge, the negative electrode potential is lowered at least once to 0.4 V or lower vs. Li to form the coating on the surface of the negative electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte battery in which gas generation is suppressed and volume change is small, and more particularly to a non-aqueous electrolyte battery in which gas generation is suppressed during high-temperature storage and a method for manufacturing the same.

Currently, non-aqueous electrolyte batteries represented by lithium ion secondary batteries are widely used as consumer non-aqueous electrolyte batteries having high energy density, such as small portable devices. Recently, as a new application, there is an increasing expectation that non-aqueous electrolyte batteries will be applied in medium and large sizes as in-vehicle power sources such as power storage facilities and HEVs.
High reliability is required to increase the size and size of nonaqueous electrolyte batteries. Generally, a non-aqueous electrolyte battery includes a positive electrode using a transition metal oxide as a positive electrode active material, a negative electrode using a carbon material as a negative electrode active material, and a non-aqueous solution in which an electrolyte salt such as LiPF ₆ is dissolved in a non-aqueous solvent such as carbonate. Although electrolytes are used, lithium ion insertion and desorption reactions with the carbon material of the negative electrode occur exclusively at a potential lower than the reductive decomposition potential of the non-aqueous electrolyte, resulting in higher energy density but lifetime and high temperature characteristics. There are weaknesses related to reliability.

  A non-aqueous electrolyte battery using lithium titanate as a negative electrode active material, in which lithium ion insertion / extraction reactions occur at a higher potential (around 1.5 V) than carbon materials, was proposed in order to improve the reliability. Has been. However, when lithium titanate is used as the negative electrode active material, gas generation occurs mainly due to the reaction between lithium titanate and a non-aqueous solvent in the initial charge / discharge process during the manufacturing process. When the gas generation reaction occurs, the output characteristics and life characteristics of the battery are deteriorated due to a change in characteristics of the electrode surface due to a decomposition reaction of the electrolyte and a change in physical properties and amount of the electrolyte. Moreover, it causes battery swelling.

  Since non-aqueous electrolyte batteries do not like the mixing of moisture into the battery, after injecting the non-aqueous electrolyte into the battery case in the manufacturing process, it is a great facility to leave it open for a long time without sealing. Since investment is required and it is not realistic, it is strongly required to seal immediately after injecting the nonaqueous electrolyte.

Non-aqueous electrolyte batteries using lithium titanate as a negative electrode active material are currently commercialized mainly as backup applications (see, for example, Non-Patent Documents 1 and 2, coin-type lithium ion secondary battery (Sony)). However, these are coin-type batteries having a maximum capacity of about 20 mAh and a maximum current of about 0.5 ItA. In a coin-type battery with a small capacity, the gas generation during the manufacturing process is not a big problem because the battery case is strong. However, when a nonaqueous electrolyte battery using lithium titanate as a negative electrode active material is increased in size, capacity, and capacity, the above gas generation cannot be overlooked. The reason for this is that if there is a section that is open after injection on the production line, the capital investment scale will be large, and the battery case will expand as the surface of the battery case increases. And when using a resin sealant that is permeable to some gases, the equilibrium point of the internal pressure is increased, which makes it more susceptible to swelling. It is done. Here, the medium / large-sized, large-capacity battery means a battery of at least 10 mAh or more, particularly 100 mAh or more, particularly 200 mAh or more.
Journal of Power Sources 146 (2005) 636-639 IEICE technical report EE2005-50 CPM2005-174

One way to mitigate the effects of gas generation such as blistering in medium and large batteries is to provide a large dead space in the battery, but such battery design conflicts with the design philosophy of high energy density batteries. is there. From this viewpoint, it is appropriate that the dead space obtained by subtracting the volume occupied by the solid matter and the liquid matter such as the power generation element / electrode element / electrolyte from the inner volume of the battery case is at least 35% by volume or less.
Of course, medium / large, large capacity non-aqueous electrolyte batteries using lithium titanate as the negative electrode active material suppress the generation of gas during the initial charge / discharge process during the manufacturing process. Therefore, there has been a demand for a technique that suppresses gas generation, particularly gas generation during high-temperature storage, and suppresses swelling of the nonaqueous electrolyte battery.
Since gas is generated on the electrode surface, it is obvious that the above problem can be solved if an ideal film can be provided on the electrode surface. However, according to the prior art, the ideal film cannot be provided. It was. For example, if a strong polyethylene film is provided on the electrode surface, the generation of hydrogen gas can be almost completely suppressed, but the electrode reaction is greatly hindered and the battery performance is extremely deteriorated. In this way, as an ideal film, it should not be dense or obstructive to the electrode reaction, and there is no increase or collapse of the film thickness even after repeated charging and discharging, It is required not to generate hydrogen gas or other gases.

Various measures for suppressing gas generation in a non-aqueous electrolyte battery using lithium titanate as a negative electrode active material have been proposed. For example, Patent Document 1 proposes optimizing a carbonaceous material that is a conductive agent. Patent Document 2 proposes to use nonstoichiometric titanium oxide as a conductive agent. Furthermore, Patent Document 1 states that “the organic solvent includes, for example, cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC). ), Chain carbonates such as diethyl carbonate (DEC), cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), chain ethers such as dimethoxyethane (DME), γ-butyrolactone (BL) acetonitrile (AN) , Sulfolane (SL), etc. ”(paragraph 0032), and Patent Document 2 also has a similar description (paragraph 0062). Specifically,“ ethylene carbonate (EC), γ -Butyrolactone (B L) mixed solvent (volume ratio 25:75) ”(paragraph 0053 of Patent Document 1, 0074 of Patent Document 2), and there is no specific description about using vinylene carbonate. Moreover, since there is no description about the formation of the coating film on the negative electrode surface, the coating film is formed on the negative electrode surface using a non-aqueous electrolyte containing vinylene carbonate based on the description in Patent Documents 1 and 2, and gas is generated during storage. It cannot be said that those skilled in the art can easily conceive the suppression.
JP 2005-100770 A JP 2005-332684 A

Patent Document 3 states that “by using a negative electrode using lithium titanate as an active material and a non-aqueous electrolyte containing diethylene glycol dimethyl ether, lithium titanate and diethylene glycol dimethyl ether react to form a surface of the lithium titanate of the negative electrode. An ion-conductive film is formed on the surface of the lithium secondary battery of the present invention by suppressing the reaction between the active material lithium titanate and the non-aqueous electrolyte. (Paragraph 0006) describes the technical idea of using a solvent capable of decomposing at a relatively noble potential at which lithium titanate operates to produce a film and improve storage characteristics. In addition, “a lithium secondary battery characterized in that the electrolyte solvent is a mixed solvent of propylene carbonate and diethylene glycol dimethyl ether” (Claim 3) is described. However, as also shown in the examples of the present specification, even if a mixed solvent of propylene carbonate and diethylene glycol dimethyl ether is used, gas generation and battery swelling cannot be sufficiently suppressed.
JP 2004-95325 A

Further, Patent Document 4 proposes to improve cycle characteristics and storage characteristics by using a separator mainly composed of polyphenylin sulfide or polyether ether ketone. Patent Document 5 proposes to improve cycle life by using a fluorinated lithium-containing titanium oxide. Further, Patent Document 4 states that “polyphenylene sulfide (PPS) or polyether ether ketone (PEEK), which is the main material of the separator, is excellent in chemical stability, and thus is almost free from lithium titanate and titanium oxide having strong reducing power. In addition, the cyclic carbonate and chain carbonate, which are nonaqueous solvents, react with lithium titanate to form a chemically stable coating on the negative electrode surface. The battery performance can be prevented from deteriorating due to the reaction of lithium titanate and titanium oxide with each other ”(paragraph 0009),“ as the cyclic carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc. Examples of the chain carbonate include dimethyl carbonate. Bonate, ethyl methyl carbonate, diethyl carbonate, etc. "(paragraph 0011), but there is no specific description about using vinylene carbonate as the cyclic carbonate (see Table 3). Since only the capacity retention rate after storage is shown, it is not shown to suppress gas generation during storage, so based on the description of Patent Documents 4 and 5, a non-aqueous electrolyte containing vinylene carbonate It cannot be said that a person skilled in the art can easily conceive of forming a film on the surface of the negative electrode in advance and suppressing gas generation during storage.
JP 2004-87229 A JP 2005-302601 A

Patent Document 6 states that “There is no particular problem when a non-aqueous electrolyte secondary battery using lithium titanate as a negative electrode active material is used as a main power source of a portable device, but this non-aqueous electrolyte secondary battery is operated. There was a problem that the battery characteristics deteriorated when used as a memory backup power source with a voltage of around 3.0 V. This is because the non-aqueous electrolyte secondary battery as described above is used as a main power source for portable devices. In this case, since the negative electrode is charged to near 0.1 V on the basis of lithium metal during charging, a film having good ion conductivity is formed on the surface of the negative electrode, and the negative electrode and the nonaqueous electrolyte react with this film. This prevents the non-aqueous electrolyte from being decomposed and the negative electrode structure from being destroyed, whereas the non-aqueous electrolyte secondary battery has an operating voltage of around 3.0V. Memory back When it is used as a power supply for a battery, it is charged with a minute current of about 1 to 5 μA while maintaining a constant voltage state of about 3.0 V for a long time, and the above negative electrode is up to about 0.8 V on the basis of lithium metal. Since only the battery is charged, the coating film as described above is not formed on the surface of the negative electrode, and the negative electrode and the non-aqueous electrolyte react to decompose the non-aqueous electrolyte or destroy the negative electrode structure. When a non-aqueous electrolyte secondary battery using lithium titanate as a negative electrode active material is charged to near 0.1 V on the basis of lithium metal, it is found on the surface of the negative electrode. Although it is described that the reaction between the negative electrode and the non-aqueous electrolyte is suppressed by the formed film, a battery having a film formed on the surface of the negative electrode charged to near 0.1 V is set to 0 with respect to the lithium potential. .Negative than 8V On the contrary, according to the description in Patent Document 6, the battery used in the negative potential region that is nobler than 0.8 V with respect to the lithium potential is used in the negative potential region. Since it is based on the premise that no film is formed on the surface, it is impeded to use a battery having a film formed on the negative electrode surface in a negative electrode potential region that is nobler than 0.8 V with respect to the lithium potential. There are reasons and it cannot be easily done by those skilled in the art. Further, as will be described later in the examples of the present specification, when a battery having a film formed on the negative electrode surface is used in a negative electrode potential region of about 0.2 V with respect to the lithium potential, Suppression and suppression of battery swelling are not sufficient, so by using a battery with a film formed on the negative electrode surface in a negative electrode potential region that is nobler than 0.8 V relative to the lithium potential, It cannot be predicted that the swelling of the battery can be significantly suppressed.
JP 2005-317509 A

Further, in the same document, “in the non-aqueous electrolyte secondary battery of the present invention, as the non-aqueous solvent used for the non-aqueous electrolyte, a known non-aqueous solvent that is generally used can be used. It is preferable to use a mixed solvent in which a carbonate and a chain carbonate are mixed, where, for example, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc. can be used as the cyclic carbonate. For example, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, or the like can be used as the non-aqueous solvent. In addition, the above Since the cyclic carbonate generally tends to be decomposed at a high potential, the ratio of the cyclic carbonate in the non-aqueous solvent is preferably in the range of 10 to 50% by volume, more preferably in the range of 10 to 30% by volume. In particular, when ethylene carbonate is used as the cyclic carbonate, the storage characteristics are excellent ”(paragraph 0025). However, non-aqueous electrolyte secondary batteries using these non-aqueous solvents are described as“ positive electrode active material in positive electrode ”. LiMn _x Ni _y Co _z O ₂ (x + y + z = 1, 0 ≦ x ≦ 0.5, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1) When used, when the mass ratio of the negative electrode active material to the positive electrode active material is 0.57 or more and 0.95 or less, the battery is charged while being maintained at a constant voltage of about 3.0 V. The voltage at the end of charging at the electrode is about 0.8 V on the basis of lithium metal, and the nonaqueous electrolyte is prevented from reacting with the negative electrode and being decomposed or the negative electrode structure being destroyed ... " As described in (paragraph 0022), “the voltage at the end of charging in the negative electrode is around 0.8 V on the basis of lithium metal”. A film is not formed, and a film is formed on the surface of the negative electrode using a non-aqueous electrolyte containing a cyclic carbonate such as “ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc.” based on the description in the same document. However, it cannot be said that those skilled in the art can easily conceive of gas generation.

Patent Document 7 discloses a compound having an S═O bond such as propane sultone or ethylene sulfite in order to improve high-load discharge characteristics of a non-aqueous electrolyte secondary battery using a lithium titanium compound as a negative electrode active material. It is described that the inclusion improves the conductivity of the electrode containing Li _4/3 Ti _5/3 O ₄ . However, as shown in the examples of the present specification, even when propane sultone (1,3-propane sultone) is contained alone in the nonaqueous electrolyte, gas generation and battery swelling are sufficiently suppressed. Can not.
JP 2003-163029 A

In addition, many proposals have been made to include various additives in the nonaqueous electrolyte of a nonaqueous electrolyte battery using a carbon material as a negative electrode for the purpose of suppressing gas generation due to the decomposition of propylene carbonate that occurs when propylene carbonate is used. (For example, refer to Patent Document 8).
Japanese Patent Laid-Open No. 2005-11768

Patent Document 9 states that “a positive electrode using a composite metal compound of at least one metal selected from the group consisting of chromium, vanadium, manganese, iron, cobalt, and nickel and lithium as a positive electrode material; and a carbon material as a negative electrode material. A lithium secondary battery comprising a negative electrode and an electrolytic solution in which an electrolyte is dissolved in a non-aqueous solvent, wherein the non-aqueous solvent is 10 wt% or more and 60 wt% or less of propylene carbonate, methyl ethyl carbonate, methyl Lithium containing 30% by weight to 80% by weight of at least one chain carbonate selected from propyl carbonate and methylbutyl carbonate and 0.01% by weight to 5% by weight of vinylene carbonate (VC) The invention of "Secondary battery" (Claim 1) is described. A lithium secondary battery using graphite having high crystallinity as a negative electrode material has a drawback that the PC in the electrolyte is decomposed by graphite during charging, and good cycle characteristics cannot be obtained. Paragraph 0003) is also intended to solve the problem, and “PC having a lower freezing point than EC and VC (freezing point −55 ° C.) is selected as the high dielectric constant solvent, and a low-viscosity chain carbonate and The present inventors have found the surprising fact that an electrolytic solution in which an electrolyte is dissolved in a non-aqueous solvent composed of VC does not decompose PC even in a graphite negative electrode and exhibits extremely excellent battery characteristics at a low temperature. Paragraph 0007), the problem inherent in non-aqueous electrolyte batteries using a carbon material for the negative electrode (the problem of suppressing battery swelling) is shown. To solve has not) been, which employs the nonaqueous solvent, the nonaqueous solvent and is not intended to suggest applying the non-aqueous electrolyte battery using the non-carbon material for the negative electrode.
Japanese Patent No. 3632389

Further, Patent Document 10 discloses that “a battery container made of a metal laminate resin sheet is provided with a wound flat power generating element having a positive electrode, a separator, and a negative electrode made of a carbon material, and an electrolytic solution, Is a mixed solvent of vinylene carbonate, propylene carbonate and chain carbonate ester, the composition of vinylene carbonate with respect to the total solvent is A volume%, and the composition of propylene carbonate with respect to the total solvent is B volume%. ≦ (A + B) ≦ 50 (where A ≠ 0 and B ≠ 0) and 3 ≦ A ≦ 20. ”(Claim 1) is described. According to the invention, “the laminate case is weak against external force and easily deformed as compared with the conventionally used metal rigid one. In particular, when left at high temperature, the electrolyte solution is vaporized, or excessive gas is generated in the battery due to electrochemical decomposition or thermal decomposition of the electrolyte solution by oxidation or reduction on the surface of the positive electrode / negative electrode active material, A battery using a laminate case expands and deforms due to an increase in battery internal pressure ”(paragraph 0005). However,“ a lithium-based battery can provide a high voltage. Therefore, it is desirable to select an electrolyte solution having excellent withstand voltage characteristics, and a candidate thereof is propylene carbonate, but when a carbon material is used for the negative electrode, propylene carbonate is decomposed. Propylene carbonate is not suitable for use in non-aqueous electrolyte battery electrolytes, despite having advantages as an electrolyte. (Paragraph 0006), “In the above embodiment, graphite is used as a material for occluding and releasing lithium, which is a negative electrode material, but the negative electrode material is not limited to this. Since it can be used as a negative electrode material if it is a releasable carbon material ”(paragraph 0063), in order to solve the problems inherent in the nonaqueous electrolyte battery using the carbon material for the negative electrode. The above mixed solvent is employed, and it does not suggest that the mixed solvent is applied to a non-aqueous electrolyte battery using a negative electrode other than a carbon material.
In addition, the present invention provides a case where the total content of vinylene carbonate and propylene carbonate (total cyclic carbonate) is higher than the content of chain carbonate by volume%, or when vinylene carbonate is less than 3 volume%. Since the expansion of the non-aqueous electrolyte battery cannot be suppressed (Tables 1 to 4), it was necessary to use a very limited mixed solvent.
Japanese Patent No. 3410027 gazette

Although Patent Documents 9 and 10 do not indicate that a film is formed on the surface of the negative electrode using a carbon material, in view of the following description of Patent Document 11, the carbon material was used as a negative electrode active material. In some cases, it is clear that a film is formed on the negative electrode surface, but when lithium titanate is used as the negative electrode active material, it cannot be said that a film is formed on the negative electrode surface.
That is, Patent Document 11 states that “a nonaqueous electrolyte secondary battery using lithium titanate as a negative electrode active material and a carbonaceous material as a conductive agent causes a reaction between the carbonaceous material and the electrolytic solution in a high temperature environment, and generates a large amount of gas. Therefore, it was found that the high temperature storage characteristics, high temperature cycle characteristics, etc. were inferior to various high temperature characteristics, etc. However, in non-aqueous electrolyte secondary batteries using a carbon material that absorbs and releases lithium as the negative electrode active material As a result of comparative examination of both, the following was found: In the charge / discharge cycle, when the negative electrode active material is a carbon material, the surface of the carbon material is coated with a film, but the negative electrode active material When lithium is titanate, the surfaces of lithium titanate and carbonaceous material are not covered with the film, and it is considered that the film suppresses gas generation due to the reaction between the carbon material and the electrolytic solution. The film has a negative electrode potential of about 0.8 V or less with respect to the Li metal potential (hereinafter, the potential is a value with respect to the Li metal potential unless otherwise specified). A particularly good film has a negative electrode potential of about 0. The carbon material that absorbs and releases lithium has a Li storage / release potential range of about 0.1 V to about 0.9 V, and the negative electrode potential is 0. For this reason, when the negative electrode potential is about 0.8 V or less, the carbon material and the electrolytic solution react to form a film, and then the carbon material exists stably. The range of the emission potential is about 1.3 V or more and about 3.0 V or less, and it is considered that no film is formed.Therefore, the Li occlusion / release potential represented by lithium titanate is higher than 1 V with respect to the potential of metallic lithium. Negative electrode active In the quality, no film was formed on the surface, and gas generation due to the reaction between the carbonaceous material as the conductive agent and the non-aqueous electrolyte could not be suppressed. ”(Paragraphs 0014 to 0017). Even when non-aqueous electrolytes such as those described in Documents 9 and 10 are used, a negative electrode active material such as lithium titanate in which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential is used. In such a case, there was no recognition that a film was formed on the negative electrode surface. Therefore, in order to form a film on the surface of the negative electrode and suppress gas generation, the non-aqueous electrolyte described in Patent Documents 9 and 10 is applied to a non-aqueous electrolyte battery using a negative electrode active material such as lithium titanate. It cannot be said that those skilled in the art can easily conceive of this.
JP 2005-317508 A

  Patent Document 11 states that, as a result of intensive studies, the present inventors have provided a negative electrode surface comprising a negative electrode containing lithium titanate and a carbonaceous material, and a nonaqueous electrolyte containing chain sulfite. It was found that a non-aqueous electrolyte secondary battery excellent in high-temperature characteristics and large current characteristics can be realized by forming a high-quality film excellent in ion conductivity ”(paragraph 0018). As described above, the film was formed on the surface of the negative electrode using lithium titanate as the negative electrode active material by adding chain sulfite to the nonaqueous electrolyte. As shown in Comparative Example in which diethyl sulfite which is a chain sulfite is contained), gas generation and battery swelling cannot be sufficiently suppressed only by forming a film on the negative electrode surface. Was Tsu.

Patent Document 12 describes a non-aqueous electrolyte battery using graphite as a negative electrode active material (paragraphs 0037 to 0039). “In the evaluation batteries A1 and A2 according to the present invention, the reduction potential is about 1.6 to 1. .7V Lithium-bis (oxalato) borate was used as a solute, so a high-quality lithium ion permeable film was formed on the negative electrode surface before the reduction of the phosphate ester compound with a reduction potential of about 1V. Thereby, it is considered that the reduction of the phosphate ester compound is suppressed and the charge / discharge efficiency is improved ”(paragraph 0049),“ In the comparative evaluation batteries X1 and X2, Does not contain lithium-bis (oxalato) borate and VC is added, and the reduction potential of VC is about 0.9 V. Therefore, VC reacts with the negative electrode, and the negative electrode Before a good quality film is formed on the surface, the reduction of the phosphate ester compound having a reduction potential of about 1 V begins, and as a result, compared with the batteries A1 and A2 containing lithium-bis (oxalato) borate in the electrolyte. Thus, it is considered that the initial charge / discharge efficiency was lowered ”(paragraph 0050), and the charge / discharge efficiency was obtained by reducing and decomposing the additive to provide a good-quality film on the negative electrode surface. Attempts to improve this are well known, and it is also well known that the reduction potential of VC is about 0.9V. However, since the operating potential of the lithium titanate negative electrode is 1.2 V or higher and normally the negative electrode potential never becomes 0.9 V or lower, in the conventional non-aqueous electrolyte battery equipped with the lithium titanate negative electrode, In order to form a film on the surface, there was no idea to select VC, which is known to have a reduction potential of about 0.9 V, as an additive.
JP 2005-255952 A

  By the way, as can be seen from the examples of Patent Documents 1, 2, 11 and the like, aluminum is conventionally used for the current collector of the lithium titanate negative electrode, but the aluminum has a potential of 0.4 V or less. Since it is well known to alloy with lithium, the idea of deeply charging such a battery until the negative electrode potential becomes 0.4 V or less cannot be derived.

  The present invention has been made in view of the above problems, and includes a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or higher with respect to a lithium potential such as lithium titanate. It is an object of the present invention to suppress gas generation of a nonaqueous electrolyte battery, particularly to suppress gas generation during high temperature storage and to suppress swelling of the nonaqueous electrolyte battery.

As a result of intensive studies to solve the above problems, the present inventors have suppressed the generation of gas that is a cause of swelling of a nonaqueous electrolyte battery including a negative electrode having a negative electrode active material such as lithium titanate. , Using a non-aqueous electrolyte containing a specific additive of VC to form a coating on the negative electrode surface, and using this non-aqueous electrolyte battery in a negative electrode potential region no less than 0.8 V with respect to the lithium potential, The present inventors reached the present invention by discovering that this coating suppresses gas generation during high-temperature storage.
As described above, the operating potential of the lithium titanate negative electrode is 1.2 V or higher, and the negative electrode potential is not normally 0.9 V or lower. Therefore, in a conventional non-aqueous electrolyte battery including a lithium titanate negative electrode, In order to form a film on the negative electrode surface, there was no idea of selecting VC having a reduction potential of about 0.9 V as an additive. However, when the present inventors tried an experiment, examples described later were used. As shown, in a non-aqueous electrolyte battery equipped with a lithium titanate negative electrode, a coating is formed on the surface of the negative electrode by using VC (even when the operation for bringing the negative electrode to a base potential of 0.9 V or less is not performed). It is surprising that a remarkable effect was achieved that the formation of gas and the generation of gas in the nonaqueous electrolyte battery was suppressed.

The present invention employs the following means in order to solve the above problems.
(1) Nonaqueous provided with a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential In the electrolyte battery, the non-aqueous electrolyte contains vinylene carbonate, the negative electrode has a coating on the surface thereof, and the battery is placed in a region of a negative electrode potential nobler than 0.8 V with respect to the lithium potential. A non-aqueous electrolyte battery characterized by being used.
(2) The nonaqueous electrolyte battery according to (1), wherein the nonaqueous electrolyte further contains 1,3-propane sultone.
(3) The nonaqueous electrolyte battery according to (1) or (2), wherein the nonaqueous solvent contains a cyclic carbonate other than vinylene carbonate and a chain carbonate.
(4) The nonaqueous electrolyte battery according to (3), wherein the cyclic carbonate is propylene carbonate, and the chain carbonate is diethyl carbonate.
(5) Content of the said vinylene carbonate is 10 mass% or less of the said nonaqueous electrolyte, The nonaqueous electrolyte battery as described in any one of said (1)-(4) characterized by the above-mentioned.
(6) The nonaqueous electrolyte battery according to (5), wherein the content of the vinylene carbonate is 0.5 to 5% by mass of the nonaqueous electrolyte.
(7) The nonaqueous electrolyte battery according to any one of (1) to (6), wherein the thickness of the coating on the negative electrode surface is 10 nm or more.
(8) The nonaqueous electrolyte battery according to any one of (1) to (7), wherein the negative electrode active material is spinel type lithium titanate.
(9) Lithium transition metal composite oxidation in which the positive electrode active material is represented by LiMn _x Ni _y Co _z O ₂ (x + y + z = 1, 0 ≦ x ≦ 0.5, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1) The nonaqueous electrolyte battery according to any one of (1) to (8), wherein the battery is a product.
(10) The nonaqueous electrolyte battery according to any one of (1) to (9), wherein the current collector of the negative electrode is copper, nickel, or an alloy thereof.
(11) Nonaqueous provided with a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or higher with respect to the lithium potential In the method of manufacturing an electrolyte battery, a nonaqueous electrolyte containing vinylene carbonate is used, and initial charge / discharge is performed under the condition that the negative electrode potential at the end of charging exceeds 0.8 V with respect to the lithium potential, and a film is formed on the negative electrode surface A method for producing a non-aqueous electrolyte battery.
(12) Nonaqueous comprising a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential In the method for producing an electrolyte battery, a nonaqueous electrolyte containing vinylene carbonate was used, and at the time of initial charge / discharge, the negative electrode potential was lowered to 0.4 V or less with respect to the lithium potential at least once to form a film on the negative electrode surface. A method for producing a nonaqueous electrolyte battery.
(13) The production of the nonaqueous electrolyte battery according to (12), wherein the negative electrode potential is lowered to 0.4 V or less with respect to the lithium potential by increasing the charging voltage at the time of initial charging / discharging than at the time of use. Method.
(14) Even in a region where the negative electrode potential is 0.4 V or less with respect to the lithium potential, the positive electrode potential does not exceed 4.5 V with respect to the lithium potential over the entire region of 0.4 V or less. (13) The method for producing a nonaqueous electrolyte battery.
(15) The method for producing a nonaqueous electrolyte battery according to any one of (11) to (14), wherein a nonaqueous electrolyte further containing 1,3-propane sultone is used during initial charge / discharge.
(16) The method for producing a nonaqueous electrolyte battery according to any one of (11) to (15), wherein the nonaqueous solvent contains a cyclic carbonate other than vinylene carbonate and a chain carbonate.
(17) The method for producing a nonaqueous electrolyte battery according to (16), wherein the cyclic carbonate is propylene carbonate, and the chain carbonate is diethyl carbonate.
(18) The method for producing a nonaqueous electrolyte battery according to any one of (11) to (17), wherein the content of the vinylene carbonate is 10% by mass or less of the nonaqueous electrolyte.
(19) The method for producing a nonaqueous electrolyte battery according to (18), wherein the content of the vinylene carbonate is 0.5 to 5% by mass of the nonaqueous electrolyte.
(20) The method for producing a nonaqueous electrolyte battery according to any one of (11) to (19), wherein the thickness of the coating on the surface of the negative electrode is 10 nm or more.
(21) The method for producing a nonaqueous electrolyte battery according to any one of (11) to (20), wherein the negative electrode active material is spinel type lithium titanate.
In addition, in said (11), (12), (13), and (15), "initial charge / discharge" means charging / discharging performed during the manufacturing process of a nonaqueous electrolyte battery.

  In the present invention, vinylene is used as a non-aqueous electrolyte of a non-aqueous electrolyte battery including a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or higher with respect to a lithium potential such as lithium titanate. By containing carbonate and having a film on the surface of the negative electrode, when the battery is used in a negative electrode potential region that is more noble than 0.8 V with respect to the lithium potential, There is an effect that gas generation during high temperature storage can be suppressed and swelling of the nonaqueous electrolyte battery can be suppressed.

Examples of the negative electrode active material used as the main component of the negative electrode included in the nonaqueous electrolyte battery according to the present invention include those in which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential. For example, tungsten oxide, molybdenum oxide, iron sulfide, titanium sulfide, lithium titanate, or the like can be used. In particular, lithium titanate represented by the chemical formula Li _{4 + x} Ti ₅ O ₁₂ (0 ≦ x ≦ 3) and having a spinel structure is preferable. Examples of the conductive agent include acetylene black, carbon black, and graphite. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

The positive electrode active material that can be used for the positive electrode included in the nonaqueous electrolyte battery according to the present invention is not limited at all, and various oxides, sulfides, and the like can be mentioned. For example, manganese dioxide (MnO ₂ ), iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (eg, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxide (eg, Li _x NiO ₂ ) , Lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel cobalt composite oxide (for example, LiNi _1-y Co _y O ₂ ), lithium nickel cobalt manganese composite oxide (LiNi _x Co _y Mn _1-yz O) ₂ ), spinel type lithium manganese nickel composite oxide (Li _x Mn _{2 -y} Ni _y O ₄ ), lithium phosphorous oxide having an olivine structure (Li _x FePO ₄ , Li _x Fe _{1 -y} Mn _y PO ₄ , Li _x etc. CoPO _4), iron sulfate _{(Fe 2 (SO 4) 3} ), vanadium oxide ( _V 2 _{O 5),} and the like if example. In addition, conductive polymer materials such as polyaniline and polypyrrole, disulfide-based polymer materials, organic materials such as sulfur (S) and carbon fluoride, and inorganic materials are also included. In particular, a lithium transition metal composite oxide represented by LiMn _x Ni _y Co _z O ₂ (x + y + z = 1, 0 ≦ x ≦ 0.5, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1) is preferable.

  A known conductive material and binder can be applied to the positive electrode according to a known formulation. Examples of the conductive agent include acetylene black, carbon black, and graphite. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber. For the positive electrode current collector, a known material can be used by a known method. For example, aluminum or an aluminum alloy can be used.

  Examples of the separator include a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), and a synthetic resin nonwoven fabric.

Examples of the supporting electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and trifluoro Examples thereof include lithium salts such as lithium metasulfonate (LiCF ₃ SO ₃ ) and bistrifluoromethylsulfonyl imitolithium [LiN (CF ₃ SO ₂ ) ₂ ].

In this invention, it is preferable to contain cyclic carbonates, such as ethylene carbonate (EC) and propylene carbonate (PC), as a nonaqueous solvent, for example. In addition, as described below, in the present invention, it is essential to contain vinylene carbonate, which is a cyclic carbonate having a carbon-carbon double bond in the ring, in addition to the cyclic carbonate as a non-aqueous solvent. . Furthermore, it is preferable to contain chain carbonates such as dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), and diethyl carbonate (DEC) together with the cyclic carbonate. The blending ratio of the cyclic carbonate and the chain carbonate as the non-aqueous solvent is not limited, but for example, the ratio of cyclic carbonate: chain carbonate can be in the range of 7: 3 to 3: 7. In addition, cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), chain ethers such as dimethoxyethane (DME), γ-butyrolactone (GBL), acetonitrile (AN), sulfolane (SL), etc. may be used. Good. As the nonaqueous electrolyte, a room temperature molten salt containing lithium ions can also be used.
When propylene carbonate is used as the cyclic carbonate and diethyl carbonate is used as the chain carbonate, the gas generation of the non-aqueous electrolyte battery is suppressed, and the effect of suppressing the swelling of the non-aqueous electrolyte battery is great, so it contains propylene carbonate and diethyl carbonate. It is more preferable to use a mixed solvent.

  In the present invention, in order to suppress swelling of the nonaqueous electrolyte battery due to gas generation, vinylene carbonate is contained in the nonaqueous electrolyte at least before the initial charge / discharge process in the manufacturing process of the nonaqueous electrolyte battery. Further, 1,3-propane sultone may be contained. The vinylene carbonate and 1,3-propane sultone are detected in the non-aqueous electrolyte provided in the non-aqueous electrolyte battery completed through the initial charge / discharge process because at least a part of the vinylene carbonate and 1,3-propane sultone disappear through the initial charge / discharge process. In some cases, the nonaqueous electrolyte battery manufactured by the manufacturing method of the present invention includes the above. When vinylene carbonate is contained in the non-aqueous electrolyte used when assembling the non-aqueous electrolyte battery, the content is preferably 10% by mass or less of the non-aqueous electrolyte in view of the effect of suppressing swelling of the non-aqueous electrolyte battery. 5 mass% is more preferable. Further, when 1,3-propane sultone is contained, the content is preferably 0.5 to 5% by weight of the nonaqueous electrolyte. By using 1,3-propane sultone together, the optimal content of vinylene carbonate or the optimal content of vinylene carbonate and 1,3-propane sultone can be reduced.

As described above, the nonaqueous electrolyte battery of the present invention contains vinylene carbonate as described above in a nonaqueous electrolyte of a nonaqueous electrolyte battery including a negative electrode having a negative electrode active material such as lithium titanate, and a negative electrode surface. In addition, the film is used in a region having a negative electrode potential nobler than 0.8 V with respect to the lithium potential, so that gas generation during high-temperature storage is suppressed by the coating.
When the nonaqueous electrolyte battery is used in a negative electrode potential region of 0.8 V or less with respect to the lithium potential, a comparative example described later (the negative electrode potential at the end of charging in the high-temperature storage test is 0.2V), gas generation during high-temperature storage is not suppressed as compared with the case where the negative electrode potential is higher than 0.8V with respect to the lithium potential.
As shown in the following examples, analysis of the gas inside the battery after leaving the nonaqueous electrolyte battery at 60 ° C. for 2 weeks revealed mainly the generation of hydrogen gas. In addition, carbon dioxide, methane, Ethylene and ethane generated gases were confirmed. It can be said that these generated gases affect the swelling of the battery. However, when vinyl alcohol is contained in the non-aqueous electrolyte of the non-aqueous electrolyte battery and a coating is present on the negative electrode surface, hydrocarbon gas (methane, ethylene, Ethane) and carbon dioxide are not present at all, or are almost absent (hydrocarbon gas and carbon dioxide are substantially not detected), thereby suppressing gas generation during high-temperature storage and swelling of the battery. It was found to be significantly smaller. Therefore, in the present invention, the gas inside the battery after being left at 60 ° C. for 2 weeks is expressed as “ratio of the total volume of methane, ethylene and ethane in the total volume of hydrogen, carbon dioxide, methane, ethylene and ethane”. Is less than 0.3% "and" the volume of carbon dioxide is less than 0.4 μl / mAh with respect to the battery capacity ".
In addition, in the non-aqueous electrolyte battery of the present invention, the above-described facts indicate that a hydrocarbon gas and a coating that does not generate carbon dioxide are contained in the non-aqueous electrolyte of the non-aqueous electrolyte battery by containing vinylene carbonate. This suggests that a film having completely different properties from the conventional film that generates carbon dioxide is formed on the surface of the negative electrode.

Furthermore, in order to suppress gas generation, it is important to have a coating having a certain thickness on the negative electrode surface. This coating has a carbonate structure.
Such a film can be formed by an electrochemical formulation as shown in the following examples, but may also be formed by a chemical or physical formulation. The present invention can be applied regardless of the type of the positive electrode active material.
In order to suppress hydrogen gas generation and suppress swelling of the nonaqueous electrolyte battery, the thickness of the coating is preferably 10 nm or more, and more preferably 10 to 20 nm.

Formation of the film on the negative electrode surface by electrochemical prescription is possible by performing initial charge / discharge before using the nonaqueous electrolyte battery. In the present invention, a nonaqueous electrolyte containing vinylene carbonate was used. In this case, as shown in Example 1, even when the initial charge / discharge is performed under the condition that the negative electrode potential at the end of charging exceeds 0.9 V with respect to the lithium potential (for example, about 1.5 V), A film is formed on the substrate, and gas generation is suppressed.
Further, as shown in Example 2, when the method of lowering the negative electrode potential to 0.4 V or less (for example, about 0.2 V) with respect to the lithium potential at least once at the time of initial charge / discharge is adopted. Thus, a film that suppresses gas generation more effectively is formed on the negative electrode surface.
The non-aqueous electrolyte battery of the present invention is used in a negative electrode potential region nobler than 0.8 V with respect to the lithium potential, but by making the charging voltage higher at the time of initial charge / discharge than at the time of use, the negative electrode The potential can be lowered to 0.4 V or less with respect to the lithium potential.
By setting the negative electrode potential to 0.4 V or less with respect to the lithium potential, it becomes easy to cause a film having a carbonate structure on the surface of the negative electrode by reductive decomposition of the non-aqueous solvent having a carbonate structure. It is preferable that
Further, as shown in the following examples, even in a region where the negative electrode potential is 0.4 V or less (for example, about 0.2 V) with respect to the lithium potential, the positive electrode potential is in relation to the lithium potential over the entire region. It is preferable to design the battery so that it is 4.5 V or less (for example, about 4.3 V).
If the positive electrode potential exceeds 4.5 V with respect to the lithium potential when the negative electrode is 0.4 V or less with respect to the lithium potential, a large amount of carbon dioxide may be generated from the positive electrode, which is not preferable.
Moreover, when lowering the negative electrode to 0.4 V or less with respect to the lithium potential, it is preferable to use copper, nickel, or an alloy thereof that does not alloy with lithium as the current collector of the negative electrode.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, these do not limit this invention at all.

(Preparation of non-aqueous electrolyte)
The following seven types of nonaqueous electrolytes were used.
[1] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) (comparative example)
[2] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) + 1 mass% VC (example of the present invention)
[3] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) + 5 mass% VC (Example of the present invention)
[4] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) + 5 mass% VC + 5 mass% PS (Example of the present invention)
[5] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) + 5 mass% PS (comparative example)
[6] 1M LiPF ₆ PC: DEC = 7: 3 (volume%) + 5 mass% DES (comparative example)
[7] 1M LiPF ₆ PC: DiEE = 5: 5 (volume%) (comparative example)

In addition, the meaning of the symbol used above is as follows.
PC: propylene carbonate DEC: diethyl carbonate VC: vinylene carbonate PS: 1,3-propane sultone DES: diethyl sulfite DiEE: diethylene glycol dimethyl ether

(Preparation of non-aqueous electrolyte battery)
90 parts by mass of lithium transition metal composite oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) powder as a positive electrode active material, 5 parts by mass of acetylene black as a conductive material, and polyvinylidene fluoride as a binder A positive electrode slurry containing 5 parts by mass of (PVdF) and using N-methylpyrrolidone (NMP) as a solvent has an electrode mixture layer density of 26 mg / cm ^{2 on} both surfaces of a positive electrode current collector (aluminum, thickness 20 μm). The positive electrode was produced by drying and pressing.

Spinel type lithium titanate (Li ₄ Ti ₅ O ₁₂ ) powder (Ishihara Sangyo Co., Ltd., product number: LT855 (Lot.0036), BET specific surface area: 3.0 m ² / g, bulk density: 1. Negative electrode active material 0 g / cm ³ , median diameter by laser diffraction scattering method: 21.2 μm) 85 parts by mass, 7 parts by mass of acetylene black as a conductive material and 8 parts by mass of polyvinylidene fluoride (PVdF) as a binder, N A negative electrode slurry containing methylpyrrolidone (NMP) as a solvent was applied on both sides of a negative electrode current collector (copper, 10 μm thick) so that the density of the electrode mixture layer was 21 mg / cm ² (excluding the current collector). Then, the negative electrode was produced by drying and pressing.

A wound electrode group formed by flatly winding the positive electrode and the negative electrode through a polyethylene porous separator is formed into an aluminum rectangular battery can (height 49.3 mm, width 33.7 mm, thickness 5.17 mm). The container was stored, and under reduced pressure, 3.5 g of each of the nonaqueous electrolytes of the above [1] to [7] was injected, and then the battery case was sealed and left at 25 ° C. overnight. Next, “initial charge / discharge” was performed. The initial charge / discharge conditions were a temperature of 25 ° C., a charge current of 100 mA, a charge voltage of 2.5 V, a charge time of 20 hours, a discharge current of 100 mA, and a discharge end voltage of 1.0 V. The positive electrode potential at the end of 2.5 V charging of this battery was about 4.0 V with respect to the lithium potential, and the negative electrode potential was about 1.5 V with respect to the lithium potential. After charging and discharging, a standing period of 30 minutes was provided, and the above charging / discharging was repeated 3 cycles. In this way, a nonaqueous electrolyte battery having a design capacity of 500 mAh was produced. The battery manufactured as described above has a 0.25 ml dead space in the battery case. The dead space is filled with vapor derived from the same volume of air and electrolyte components after sealing and before the initial charge / discharge step.
As described above, non-aqueous electrolyte batteries of Experiment No. 1-1 to No. 1-7 using non-aqueous electrolytes [1] to [7], respectively, were produced.
After fabrication, one cycle of charge / discharge was performed under the same conditions as the initial charge / discharge of the battery, and the discharge capacity (initial battery capacity) was measured. Moreover, the battery thickness change during the initial charge / discharge process was evaluated by measuring the thickness of the battery center before and after the initial charge / discharge process.

(High temperature storage test)
The battery manufactured as described above was subjected to a high temperature storage test. That is, the charging current is 100 mA, the charging voltage is 2.5 V (the negative electrode potential at the end of charging is about 1.5 V with respect to the lithium potential), and the constant current and constant voltage charging is performed for 20 hours. Left for 2 weeks. After leaving at the temperature of 25 ° C. for 1 day, the battery center thickness was measured again, and the difference from the thickness measured before the initial charge / discharge process was determined. Subsequently, constant current discharge with a discharge current value of 100 mA and a discharge end voltage of 1.0 V was performed, and the remaining capacity was measured.

(Measurement of film thickness)
The negative electrode surface of the battery produced as described above was observed with an X-ray photoelectron spectrometer (XPS). XPS measurement is performed by irradiating the sample with X-rays and observing the rebound data. Since the minimum incident depth of X-rays is 10 nm, the surface layer portion within 10 nm at the start of measurement. Is obtained as averaged data. Therefore, when a peak peculiar to the active material exists at the start of measurement, the thickness is set to 10 nm or less. When no peak specific to the active material is observed at the start of measurement and only information on a film having a carbonate structure appears, the thickness of the film is set to 10 nm or more, and then a sample is prepared at a speed of 2 nm per minute by Ar sputtering. The measurement was continued while digging, and when the information specific to the active material was mixed, the thickness of the coating was determined.

(Measurement of gas amount and analysis of gas components)
The amount of gas in the battery was measured according to the following procedure. A water tank filled with liquid paraffin was prepared, and a graduated graduated cylinder was submerged in the water tank. The battery was submerged in the water tank, the battery tank was opened in the water tank, and the gas in the battery was collected in the graduated cylinder as bubbles. The collected gas volume was determined by reading the scale of the graduated cylinder and used as the amount of gas in the battery.
The collected gas was subjected to quantitative analysis using a gas chromatography (GC) analyzer (manufactured by Shimadzu Corporation, model number: GC-14BPTF). In the analysis, calibration curves were obtained using standard gases for hydrogen, nitrogen, oxygen, carbon dioxide, methane, ethylene and ethane. The number of repeated measurements for the same measurement target component was 2 or more, and reproducibility was confirmed. The measurement conditions were as follows: for hydrogen, nitrogen and oxygen, DB5MS was used for the column, the column temperature was 40 ° C., and TCD was used for the detector. For carbon dioxide, methane, ethylene and ethane, Carbo-bond was used for the column, the column temperature was 50 ° C., TCD was used for carbon dioxide, and CDD was used for methane, ethylene and ethane. The amount of injected gas was 50 μl.
From the quantitative results, the ratio of the total volume of methane, ethylene, and ethane in the total volume of hydrogen, carbon dioxide, methane, ethylene, and ethane was calculated.
The volume of carbon dioxide in the battery gas is determined by determining the ratio of the volume of carbon dioxide in the volume excluding nitrogen and oxygen based on the data obtained as a result of GC measurement, and measuring the amount of gas in the battery. The value obtained by multiplying the volume obtained by subtracting the volume of the dead space in the battery case (0.25 ml in this embodiment) from the obtained volume.
That is, in the above calculation, the amount of carbon dioxide originally present in the air is ignored, and it is assumed that nitrogen and oxygen are derived only from those originally present in the air. According to such a calculation method, since the measurement values of nitrogen and oxygen are not included in the calculation basis, even if there is a possibility that air in the analysis chamber may be mixed into the measurement sample in the course of gas analysis, The influence can be excluded.

  Table 1 shows the measurement results of the change in battery thickness, the battery capacity, the coating thickness on the negative electrode surface, and the amount of gas in the battery (gas component).

From Table 1, when the initial charging / discharging process is performed under the condition that the negative electrode potential at the end of charging is about 1.5 V with respect to the lithium potential, that is, when overcharging is not performed, the following is performed. I can say that.
First, the increase in battery thickness after being allowed to stand at 60 ° C. for 2 weeks (hereinafter referred to as “after being left at 60 ° C.”) is due to the film thickness on the negative electrode surface, the addition of VC to the non-aqueous electrolyte, “Hydrogen, carbon dioxide, methane, ethylene and ethane in the total volume ratio of the total volume of methane, ethylene, and ethane” (hereinafter referred to as “hydrocarbon fraction”) and the amount of carbon dioxide generated I found out.
The comparative battery (Experiment No. 1-1) using the non-aqueous electrolyte [1] containing no additive had a coating thickness of less than 10 nm, a large hydrocarbon fraction of 3.8%, carbon dioxide Since the generation amount is 0.4 μl / mAh or more, the increase in battery thickness after standing at 60 ° C. is large.
In contrast, the battery of the present invention using a non-aqueous electrolyte [3] containing VC as an additive and a non-aqueous electrolyte [4] containing PS in addition to VC (Experiment No. 1-3 and No.1-4) has a film thickness of 10 to 20 nm, methane, ethylene, and ethane, which are hydrocarbon gases, are not substantially detected (hydrocarbon fraction is 0), and the amount of carbon dioxide generated is 0. Since it is less than 4 μl / mAh, the increase in battery thickness after standing at 60 ° C. is small.
Regarding the content of VC, the battery using the nonaqueous electrolyte [2] containing 1% by mass VC is 60% more than the battery using the nonaqueous electrolyte [3] containing 5% by mass VC. The increase in battery thickness after leaving at ℃ was small.
However, the battery of the comparative example (experiment No. 1-5) using the non-aqueous electrolyte [5] containing only PS as an additive has a coating thickness of less than 10 nm and a hydrocarbon fraction of 0.4%. Therefore, the increase in battery thickness after standing at 60 ° C is greatly improved compared to the battery using the non-aqueous electrolyte [1] containing no additive (Experiment No. 1-1). It has not been done.
A comparative battery (Experiment No. 1-6) using a nonaqueous electrolyte [6] containing DES as an additive had a coating thickness of 10 to 20 nm, but a hydrocarbon fraction of 56.2%. Since the amount of carbon dioxide generated is large, the increase in battery thickness after standing at 60 ° C. was the largest.
The battery of the comparative example (Experiment No. 1-7) using the nonaqueous electrolyte [7] using a mixed solvent of PC and DiEE had a coating thickness of 10 to 20 nm and a hydrocarbon fraction of 12. The battery thickness increase after standing at 60 ° C is larger than 9%, compared to the battery (Experiment No. 1-1) using the non-aqueous electrolyte [1] using a mixed solvent of PC and DEC that does not contain additives. Was also big.

  Further, the battery of the present invention having a small increase in battery thickness after leaving at high temperature using non-aqueous electrolytes [2], [3], and [4] containing VC as an additive is non-aqueous electrolyte [1], [ The remaining capacity after being left at 60 ° C. was larger than that of the comparative battery having a large increase in battery thickness after being left at 60 ° C. using 5] to [7].

In the initial charge / discharge step, experiments No. 2-1 to No. 2 using the nonaqueous electrolytes [1] to [7] were performed in the same manner as in Example 1 except that the charge voltage was set to 4.1 V. 2-7 non-aqueous electrolyte batteries were prepared. The positive electrode potential at the end of 4.1 V charging of this battery was about 4.3 V with respect to the lithium potential, and the negative electrode potential was about 0.2 V with respect to the lithium potential. After the production, except that the charging voltage was changed to 2.5 V, one cycle of charge / discharge was performed under the same conditions as the initial charge / discharge of this battery, and the discharge capacity (initial battery capacity) was measured.
The high temperature standing test, the coating thickness measurement, the gas amount measurement and the gas component analysis were performed in the same manner as in Example 1.
Table 2 shows the measurement results of changes in battery thickness, battery capacity, coating thickness on the negative electrode surface, and the amount of gas in the battery (gas component).

From Table 2, when the initial charging / discharging process is performed under the condition that the negative electrode potential at the end of charging is about 0.2 V with respect to the lithium potential, that is, when overcharging is performed, the battery thickness after standing at 60 ° C. It was found that the increase in is related to the addition of VC to the non-aqueous electrolyte, the hydrocarbon fraction in the components of the gas inside the battery, and the amount of carbon dioxide generated.
When the battery of the comparative example (Experiment No. 2-1) using the nonaqueous electrolyte [1] containing no additive is overcharged, a film having a thickness of 10 to 20 nm is formed. Since the hydrocarbon fraction was larger (3.8% → 5.0%) and the amount of carbon dioxide generation was larger (0.4 μl / mAh → 1.1 μl / mAh) than in the case of not performing the process, 60 The increase in battery thickness after standing at ℃ increased.
In contrast, the battery of the present invention using a non-aqueous electrolyte [3] containing VC as an additive and a non-aqueous electrolyte [4] containing PS in addition to VC (Experiment No. 2-3 and In No.2-4), when overcharged, hydrocarbon gases such as methane, ethylene, and ethane are not substantially detected (hydrocarbon fraction is 0), and carbon dioxide is substantially not. Since it was not detected, the increase in battery thickness after leaving at 60 ° C. was even smaller than when overcharging was not performed.
A battery using a non-aqueous electrolyte [2] containing 1% by mass of VC also has a small increase in battery thickness after being left at 60 ° C. when overcharged, compared to the case without overcharge. However, the battery using the non-aqueous electrolyte [3] containing 5% by mass VC was significantly smaller.
However, the battery of the comparative example (experiment No. 2-5) using the nonaqueous electrolyte [5] containing only PS as an additive was carbonized more when overcharged than when not overcharged. On the contrary, since the hydrogen fraction increased (0.4% → 3.3%), the increase in battery thickness after standing at 60 ° C. increased.
The battery of the comparative example (Experiment No. 2-6) using the nonaqueous electrolyte [6] containing DES as an additive is more hydrocarbon when overcharged than when not overcharged. Since the fraction was further increased (56.2% → 78.5%), the increase in battery thickness after standing at 60 ° C. was increased.
A comparative battery (Experiment No. 2-7) using a non-aqueous electrolyte [7] using a mixed solvent of PC and DiEE has a large hydrocarbon fraction of 18.6% when overcharged. Therefore, the increase in battery thickness after being left at 60 ° C. is large (a little smaller than the case where overcharge is not performed).

(High rate discharge test)
Several batteries prepared in Example 2 (Experiment No. 3-1, No. 3-2, No. 3-3, No. 3-4 batteries are the same as Experiment No. 2-1, No. 3, respectively. .2-3, No.2-4, and No.2-5) were subjected to a high rate discharge test. After battery preparation and in a high temperature storage test, after charging at a constant current and a constant voltage with a charging current of 100 mA and a charging time of 20 hours, a discharge current of 500 mA (corresponding to 1 It) or 3500 mA (corresponding to 7 It) is 1.0 V. Each was discharged to the end voltage, and the discharge capacity was recorded.
Table 3 shows the results of the high rate discharge test.

  From Table 3, the battery of the present invention example using the nonaqueous electrolyte [3] containing VC as an additive (Experiment No. 3-2), the nonaqueous electrolyte [4] further containing PS in addition to VC The battery of the present invention used (Experiment No. 3-3) was a comparative example battery (Experiment No. 3-1) using a non-aqueous electrolyte [1] containing no additive, and only PS was used as an additive. Compared to the comparative battery using the nonaqueous electrolyte [5] (Experiment No. 3-4), there is little decrease in the remaining capacity after leaving at 60 ° C. even when performing high rate discharge. I understand.

(Comparative example)
In a battery (experiment No. 2-4) using non-aqueous electrolyte [4] containing PS in addition to VC as an additive, in a high temperature standing test, the charging voltage was 4.1 V (the negative electrode potential at the end of charging was The change in battery thickness, battery capacity, and gas amount (gas component) were measured in the same manner as in Example 2 except that the voltage was about 0.2 V with respect to the lithium potential.
The results are shown in Table 4 together with the results of Experiment No. 2-4 of Example 2.

  As shown in Table 4, a battery using a nonaqueous electrolyte [4] containing PS in addition to VC as an additive was subjected to a high-temperature standing test with a charging voltage of 2.5 V (the negative electrode potential is relative to the lithium potential). In the case of about 1.5 V) (Experiment No. 2-4), the change in battery thickness was 0.1 mm, whereas in the high temperature standing test, the charging voltage was 4.1 V (the negative electrode potential was In the case of about 0.2 V with respect to the lithium potential (Experiment No. 4-1), the change in battery thickness is 0.8 mm, which is larger than the former case. It can be seen that it is important to use the nonaqueous electrolyte battery of the invention in a region of a negative electrode potential nobler than 0.8 V with respect to the lithium potential.

As in Example 1, except that the following two types [1] and [2] were used as the non-aqueous electrolyte, Experiments No. 5-1 and No. 5-2 ([1] and [2 ] Was used and tested.
[1] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) (comparative example)
[2] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) + 5 mass% VC (Example of the present invention)

  Table 5 shows the measurement results of the change in battery thickness, the battery capacity, the coating thickness on the negative electrode surface, and the amount of gas in the battery (gas component).

From Table 5, when the nonaqueous electrolyte of PC: DEC = 5: 5 (volume%) is used and overcharging is not performed, the increase in battery thickness after leaving at 60 ° C. is due to the coating thickness on the negative electrode surface and the nonaqueous electrolyte. It was found that this was related to the addition of VC, the hydrocarbon fraction in the components of the gas inside the battery, and the amount of carbon dioxide generated, particularly the amount of carbon dioxide generated.
In the comparative battery (Experiment No. 5-1) using the non-aqueous electrolyte [1] containing no additive, hydrocarbon gases such as methane, ethylene, and ethane were not substantially detected (hydrocarbon). However, since the coating thickness is less than 10 nm and the carbon dioxide generation amount is as large as 0.7 μl / mAh, the increase in battery thickness after leaving at 60 ° C. is large.
On the other hand, the battery of the present invention example (experiment No. 5-2) using the nonaqueous electrolyte [2] containing VC as an additive has a coating thickness of 10 to 20 nm and is a hydrocarbon gas. Methane, ethylene, and ethane are not substantially detected (hydrocarbon fraction is 0), and the amount of carbon dioxide generated is less than 0.4 μl / mAh, so the increase in battery thickness after standing at 60 ° C. is small.

As in Example 2, Experiments No. 6-1 to No. 6-5 ([1] to [5] respectively) were performed in the same manner as in Example 2 except that the following five types [1] to [5] were used as the nonaqueous electrolyte. ] Was used and tested.
[1] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) (comparative example)
[2] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) + 5 mass% VC (Example of the present invention)
[3] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) + 5 mass% VC + 5 mass% PS (Example of the present invention)
[4] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) + 10 mass% VC (Example of the present invention)
[5] 1M LiPF ₆ PC: DEC = 5: 5 (volume%) + 20 mass% VC (Example of the present invention)

  Table 6 shows the measurement results of the change in battery thickness, the battery capacity, the coating thickness on the negative electrode surface, and the amount of gas in the battery (gas component).

From Table 6, when using a non-aqueous electrolyte of PC: DEC = 5: 5 (volume%) and overcharging, the increase in battery thickness after standing at 60 ° C. is the addition of VC to the non-aqueous electrolyte, the battery It was found to be related to the hydrocarbon fraction in the components of the internal gas and the amount of carbon dioxide generated, especially the amount of carbon dioxide generated.
When the battery of the comparative example (Experiment No. 6-1) using the non-aqueous electrolyte [1] containing no additive is overcharged, a film having a thickness of 10 to 20 nm is formed. Since the amount of carbon dioxide generated was larger than when not performed (0.7 μl / mAh → 2.0 μl / mAh), the increase in battery thickness after standing at 60 ° C. was larger.
On the other hand, the battery of the present invention using the nonaqueous electrolyte [2] containing 5 mass% VC as an additive and the nonaqueous electrolyte [3] containing PS in addition to VC (Experiment No. 6) -2 and No. 6-3), when overcharged, a film with a thickness of 10 to 20 nm is formed, and hydrocarbon gases methane, ethylene, and ethane are not substantially detected ( Since the hydrocarbon fraction was 0) and carbon dioxide was not substantially detected, the increase in battery thickness after standing at 60 ° C. was even smaller than when overcharging was not performed.
Moreover, when overcharge is performed, as the content of VC in the non-aqueous electrolyte increases to 10 mass% VC (non-aqueous electrolyte [4]) and 20 mass% VC (non-aqueous electrolyte [5]), Since the amount of carbon dioxide generated increases and the battery thickness increases after being left at 60 ° C. (Experiment No. 6-4 and No. 6-5), the VC content is preferably 10% by mass or less. It was.

As in Example 1, except that the following seven types of {1} to {7} were used as the nonaqueous electrolyte, Experiments No. 7-1 to No. 7-7 (respectively {1} to {7 } Were used and tested.
{1} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) (comparative example)
{2} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 0.5 mass% VC (example of the present invention)
{3} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)
{4} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 3 mass% VC (example of the present invention)
{5} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 5 mass% VC (example of the present invention)
{6} 1M LiPF ₆ PC: MEC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)
{7} 1M LiPF ₆ PC: DMC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)

  Table 7 shows the measurement results of changes in battery thickness, battery capacity, coating thickness on the negative electrode surface, and gas amount in the battery.

From Table 7, overcharge was performed using a nonaqueous electrolyte of PC: DEC = 3: 7 (volume%), PC: MEC = 3: 7 (volume%), PC: DMC = 3: 7 (volume%). In the absence, the increase in battery thickness after standing at 60 ° C. was found to be related to the coating thickness on the negative electrode surface and the addition of VC to the non-aqueous electrolyte.
The comparative battery (Experiment No. 7-1) using the non-aqueous electrolyte {1} containing no additive has a coating thickness of less than 10 nm and the increase in battery thickness after standing at 60 ° C. is extremely large. On the other hand, in the batteries of the present invention examples using the nonaqueous electrolytes {2} to {5} containing VC (experiment No. 7-2 to No. 7-5), the coating thickness is 10 to 20 nm. The increase in battery thickness after standing at 60 ° C. is small, and in the range of 0.5 to 5% by mass, the increase in battery thickness is small when the VC content is small.
In addition, when various chain carbonates are blended at the same blending ratio and the VC content is the same, the battery thickness is increased by using a mixed solvent of propylene carbonate (PC) and diethyl carbonate (DEC). Batteries (Experiment No. 7-3) are most suppressed, batteries using a mixed solvent of propylene carbonate (PC) and methyl ethyl carbonate (MEC) (Experiment No. 7-6), propylene carbonate (PC) and dimethyl carbonate It increased in order of the battery (experiment No. 7-7) using the mixed solvent of (DMC).

As in Example 2, experiment No. 8-1 (using {1}), No. 1 was used except that the following six types of {1} and {3} to {7} were used as the nonaqueous electrolyte. Non-aqueous electrolyte batteries of 8-2 to No. 8-6 (respectively using {3} to {7} in order) were fabricated and tested.
{1} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) (comparative example)
{3} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)
{4} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 3 mass% VC (example of the present invention)
{5} 1M LiPF ₆ PC: DEC = 3: 7 (volume%) + 5 mass% VC (example of the present invention)
{6} 1M LiPF ₆ PC: MEC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)
{7} 1M LiPF ₆ PC: DMC = 3: 7 (volume%) + 1 mass% VC (Example of the present invention)

  Table 8 shows the measurement results of the change in battery thickness, the battery capacity, the coating thickness on the negative electrode surface, and the amount of gas in the battery.

From Table 8, overcharge was performed using a nonaqueous electrolyte of PC: DEC = 3: 7 (volume%), PC: MEC = 3: 7 (volume%), PC: DMC = 3: 7 (volume%). The increase in battery thickness after standing at 60 ° C. was found to be related to the addition of VC to the non-aqueous electrolyte.
When the battery of the comparative example (Experiment No. 8-1) using the non-aqueous electrolyte {1} containing no additive is overcharged, a film having a thickness of 10 to 20 nm is formed. The increase in battery thickness after standing at 60 ° C. was greater than when no treatment was performed.
On the other hand, in the batteries of the present invention using the nonaqueous electrolytes {3} to {5} (PC / DEC) containing VC as an additive (Experiment No. 8-2 to No. 8-4) When overcharging was performed, a film having a thickness of 10 to 20 nm was formed, and the increase in battery thickness after standing at 60 ° C. was even smaller than when overcharging was not performed. In particular, in the case of a battery having a VC content of 3 or 5% by mass, the effect of suppressing the increase in battery thickness is remarkable.
Batteries of the present invention examples using nonaqueous electrolytes {6} and {7} containing VC as an additive and nonaqueous solvents being PC / MEC and PC / DMC (Experiment Nos. 8-5 and 8) In -6), when overcharging was performed, the increase in battery thickness after standing at 60 ° C. was greater than when overcharging was not performed. This tendency is particularly remarkable in PC / DMC.

As in Example 1, experiments No. 9-1 to No. 9-3 (<1> to <3, respectively) were performed as in Example 1 except that the following three types of <1> to <3> were used as the nonaqueous electrolyte. The nonaqueous electrolyte battery was used and tested.
<1> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) (comparative example)
<2> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) + 5 mass% VC (example of the present invention)
<3> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) + 5 mass% VC + 5 mass% PS (Example of the present invention)

  Table 9 shows the measurement results of the change in battery thickness, battery capacity, coating thickness on the negative electrode surface, and the amount of gas in the battery.

From Table 9, when the nonaqueous electrolyte of EC: DEC = 5: 5 (volume%) is used and overcharging is not performed, the increase in battery thickness after standing at 60 ° C. is due to the coating thickness on the negative electrode surface and the nonaqueous electrolyte. It was found that this was related to the addition of VC, the hydrocarbon fraction in the components of the gas inside the battery, and the amount of carbon dioxide generated, particularly the amount of carbon dioxide generated.
The battery of the comparative example (Experiment No. 9-1) using the nonaqueous electrolyte <1> containing no additive has a coating thickness of less than 10 nm, whereas the increase in battery thickness after standing at 60 ° C. is large. The battery of the present invention example using the nonaqueous electrolyte <2> containing VC as an additive (Experiment No. 9-2) has a coating thickness of 10 to 20 nm, and the battery thickness after standing at 60 ° C. Although the increase was slightly suppressed, it was not sufficiently suppressed because of the large amount of carbon dioxide generated.
The battery (Experiment No. 9-3) of the present invention using the nonaqueous electrolyte <3> containing PS in addition to VC has a coating thickness of 10 to 20 nm and is a hydrocarbon gas such as methane or ethylene. , And ethane are not substantially detected (hydrocarbon fraction is 0), and the amount of carbon dioxide generated is less than 0.4 μl / mAh, so the increase in battery thickness after standing at 60 ° C. is small.
Regarding the effect of suppressing the increase in battery thickness, the battery using a mixed solvent of PC and DEC as a non-aqueous solvent is more effective in increasing the battery thickness due to the addition of VC than the battery using a mixed solvent of EC and DEC. It was found that the suppression effect was great.

As in Example 2, experiments No. 10-1 to No. 10-3 (<1> to <3, respectively) were performed as in Example 2 except that the following three types of <1> to <3> were used. The nonaqueous electrolyte battery was used and tested.
<1> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) (comparative example)
<2> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) + 5 mass% VC (example of the present invention)
<3> 1M LiPF ₆ EC: DEC = 5: 5 (volume%) + 5 mass% VC + 5 mass% PS (Example of the present invention)

  Table 10 shows the measurement results of the change in battery thickness, battery capacity, coating thickness on the negative electrode surface, and the amount of gas in the battery (gas component).

From Table 10, when EC: DEC = 5: 5 (volume%) non-aqueous electrolyte was used and overcharging was performed, the increase in battery thickness after standing at 60 ° C. was due to the addition of VC to the non-aqueous electrolyte, the battery It was found to be related to the hydrocarbon fraction in the components of the internal gas and the amount of carbon dioxide generated, especially the amount of carbon dioxide generated.
When the battery of the comparative example (Experiment No. 10-1) using the non-aqueous electrolyte <1> containing no additive is overcharged, a film with a thickness of 10 to 20 nm is formed. Since the amount of carbon dioxide generated was larger than when not performing (0.4 μl / mAh → 1.7 μl / mAh), the increase in battery thickness after standing at 60 ° C. was larger.
On the other hand, the battery of the present invention using the nonaqueous electrolyte <2> containing 5 mass% VC as an additive and the nonaqueous electrolyte <3> containing PS in addition to VC (Experiment No. 10) -2 and No. 10-3), when overcharged, a film with a thickness of 10 to 20 nm is formed, and hydrocarbon gases methane, ethylene, and ethane are not substantially detected ( Since the hydrocarbon fraction was 0) and carbon dioxide was scarcely present or substantially absent, the increase in battery thickness after standing at 60 ° C. was even smaller than when overcharging was not performed.

  As described above, in a nonaqueous electrolyte battery including a negative electrode having a negative electrode active material such as lithium titanate, the nonaqueous electrolyte contains vinylene carbonate, or vinylene carbonate and 1,3-propane sultone, and the negative electrode surface is coated. And the use of the negative electrode potential in a region nobler than 0.8 V with respect to the lithium potential suppresses gas generation during high-temperature storage and suppresses battery swelling. confirmed.

  When the non-aqueous electrolyte battery of the present invention is a medium / large-sized, large-capacity non-aqueous electrolyte battery, it is possible to alleviate the influence of swell due to gas generation. Can be used for many applications.

Claims (21)

  In a nonaqueous electrolyte battery comprising a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential The non-aqueous electrolyte contains vinylene carbonate, the negative electrode has a coating on the surface thereof, and the battery is used in a negative electrode potential region nobler than 0.8 V with respect to the lithium potential. The nonaqueous electrolyte battery characterized by the above-mentioned.   The nonaqueous electrolyte battery according to claim 1, wherein the nonaqueous electrolyte further contains 1,3-propane sultone.   The nonaqueous electrolyte battery according to claim 1, wherein the nonaqueous solvent contains a cyclic carbonate other than vinylene carbonate and a chain carbonate.   The non-aqueous electrolyte battery according to claim 3, wherein the cyclic carbonate is propylene carbonate, and the chain carbonate is diethyl carbonate.   5. The non-aqueous electrolyte battery according to claim 1, wherein a content of the vinylene carbonate is 10% by mass or less of the non-aqueous electrolyte.   The non-aqueous electrolyte battery according to claim 5, wherein the content of the vinylene carbonate is 0.5 to 5% by mass of the non-aqueous electrolyte.   The nonaqueous electrolyte battery according to claim 1, wherein a thickness of the coating on the negative electrode surface is 10 nm or more.   The non-aqueous electrolyte battery according to claim 1, wherein the negative electrode active material is spinel type lithium titanate. The positive electrode active material is a lithium transition metal composite oxide represented by LiMn _x Ni _y Co _z O ₂ (x + y + z = 1, 0 ≦ x ≦ 0.5, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1). The nonaqueous electrolyte battery according to claim 1, wherein the battery is a nonaqueous electrolyte battery.   The nonaqueous electrolyte battery according to claim 1, wherein the current collector of the negative electrode is copper, nickel, or an alloy thereof.   A nonaqueous electrolyte battery comprising a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential In the production method, using a non-aqueous electrolyte containing vinylene carbonate, initial charge / discharge was performed under the condition that the negative electrode potential at the end of charge exceeded 0.8 V with respect to the lithium potential, and a film was formed on the negative electrode surface. A method for producing a non-aqueous electrolyte battery.   A nonaqueous electrolyte battery comprising a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode, and a negative electrode having a negative electrode active material into which lithium ions are inserted and desorbed at a potential of 1.2 V or more with respect to the lithium potential In the production method, a nonaqueous electrolyte containing vinylene carbonate is used, and at the time of initial charge / discharge, the negative electrode potential is lowered to 0.4 V or less with respect to the lithium potential at least once to form a coating on the negative electrode surface. A method for producing a nonaqueous electrolyte battery.   13. The method for producing a nonaqueous electrolyte battery according to claim 12, wherein the negative electrode potential is lowered to 0.4 V or less with respect to the lithium potential by increasing the charging voltage at the time of initial charging / discharging than at the time of use.   The positive electrode potential does not exceed 4.5 V with respect to the lithium potential over the entire region of 0.4 V or less even in the region where the negative electrode potential is 0.4 V or less with respect to the lithium potential. The manufacturing method of the nonaqueous electrolyte battery as described in any one of.   The method for producing a nonaqueous electrolyte battery according to any one of claims 11 to 14, wherein a nonaqueous electrolyte further containing 1,3-propane sultone is used during initial charge and discharge.   The said nonaqueous solvent contains cyclic carbonates other than vinylene carbonate, and a chain carbonate, The manufacturing method of the nonaqueous electrolyte battery as described in any one of Claims 11-15 characterized by the above-mentioned.   The method for producing a nonaqueous electrolyte battery according to claim 16, wherein the cyclic carbonate is propylene carbonate, and the chain carbonate is diethyl carbonate.   The method for producing a nonaqueous electrolyte battery according to any one of claims 11 to 17, wherein the content of the vinylene carbonate is 10% by mass or less of the nonaqueous electrolyte.   The method for producing a nonaqueous electrolyte battery according to claim 18, wherein the content of the vinylene carbonate is 0.5 to 5 mass% of the nonaqueous electrolyte.   The method for producing a nonaqueous electrolyte battery according to any one of claims 11 to 19, wherein the thickness of the coating on the surface of the negative electrode is 10 nm or more.   The method for producing a nonaqueous electrolyte battery according to any one of claims 11 to 20, wherein the negative electrode active material is spinel type lithium titanate.