JP2007250288A - Method for manufacturing non-aqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-aqueous electrolyte secondary battery with improved initial output property by applying a special aging process to the non-aqueous electrolyte secondary battery provided with non-aqueous electrolyte to which lithium salt with oxalato complex made to be an anion is added. <P>SOLUTION: The method for manufacturing the non-aqueous electrolyte secondary battery 10 forms the secondary battery by inserting a positive electrode 11 containing a lithium transition metal composite oxide carrying out occlusion and discharging of lithium as a positive electrode active substance and a negative electrode 12 containing carbon carrying out occlusion and discharging of lithium as a negative electrode active substance inside an exterior can 14 and then injecting the non-aqueous electrolyte with the lithium salt with the oxalato complex made as anion is added inside the exterior can 14. Next, after injecting the non-aqueous electrolyte to which the lithium salt with the oxalato complex made as anion is added, the aging process of leaving the secondary battery in a temperature environment of 35°C to 85°C with battery voltage at 1V or more before shipping for only less than 7 days is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention inserts a positive electrode containing a lithium transition metal composite oxide capable of occluding and releasing lithium as a positive electrode active material and a negative electrode containing carbon capable of occluding and releasing lithium as a negative electrode active material in an outer can. Then, the present invention relates to a method for producing a non-aqueous electrolyte secondary battery formed by pouring a non-aqueous electrolyte solution to which a lithium salt having an oxalato complex as an anion is added into the outer can.

In recent years, as a battery used in portable electronic / communication equipment such as a small video camera, a mobile phone, and a laptop computer, a carbon material or an alloy capable of inserting and extracting lithium ions is used as a negative electrode active material, and lithium cobalt oxide (LiCoO _2). ), Non-aqueous electrolyte secondary batteries using lithium-containing transition metal oxides such as lithium manganate (LiMn ₂ O ₄ ) and lithium nickelate (LiNiO ₂ ) as a positive electrode active material are small, lightweight, high voltage, and high It has come into practical use as a battery that can be charged and discharged with a capacity.

Among the lithium-containing transition metal oxides used for the positive electrode active material of the non-aqueous electrolyte secondary battery described above, lithium nickelate (LiNiO ₂ ) has a high capacity but is inferior in safety. Moreover, it was inferior to lithium cobaltate because it had the disadvantage of a large overvoltage. In addition, lithium manganate (LiMn ₂ O ₄ ) has the feature of being rich in resources and inexpensive, but has the disadvantage that manganese itself dissolves at high temperature at low energy density. Was also inferior. For this reason, it has become mainstream to use lithium cobaltate (LiCoO ₂ ) as the lithium-containing transition metal oxide.

  By the way, in recent years, a lithium-manganese composite oxide having a spinel structure and a lithium-nickel composite oxide having a layered structure are mixed and used for a positive electrode active material of a non-aqueous electrolyte secondary battery. A non-aqueous electrolyte secondary battery has been proposed which can appropriately set the balance of the battery and improve the storage characteristics in a high temperature environment. However, even in a nonaqueous electrolyte secondary battery using a positive electrode active material in which a lithium manganese composite oxide having a spinel structure and a lithium nickel composite oxide having a layered structure are mixed, it is stored in a high temperature environment. It has been difficult to sufficiently suppress deterioration of battery characteristics such as charge / discharge characteristics.

  On the other hand, it has been proposed to use lithium-bis (oxalato) borate as the solute of the non-aqueous electrolyte to improve the cycle characteristics of the non-aqueous electrolyte secondary battery in a high temperature environment. However, the non-aqueous electrolyte secondary battery using lithium-bis (oxalato) borate has a problem that the internal resistance of the battery is increased and the battery characteristics such as charge / discharge characteristics are deteriorated.

  Therefore, in a non-aqueous electrolyte secondary battery using a positive electrode active material in which a lithium manganese composite oxide having a spinel structure and a lithium nickel composite oxide having a layered structure are mixed, the internal resistance of the battery is increased. However, Patent Document 1 has been proposed to sufficiently suppress deterioration of battery characteristics such as charge / discharge characteristics when stored in a high temperature environment.

In the non-aqueous electrolyte secondary battery proposed in Patent Document 1, a lithium salt having an oxalato complex as an anion is added to a non-aqueous electrolyte obtained by dissolving a solute in a non-aqueous solvent. I am doing so. As a result, a lithium-salt having the oxalato complex as an anion forms a stable film on the surface of the positive electrode and the negative electrode even in a high temperature environment. Further, side reactions are prevented from being caused by direct contact with the negative electrode, and high temperature storage characteristics are improved.
JP 2005-243504 A

However, in the non-aqueous electrolyte secondary battery proposed in Patent Document 1 described above, the initial output characteristics, that is, the initial IV characteristics (IV resistance: Note that the IV resistance is a current value at several points in the battery. The voltage when charging or discharging for a certain period of time is measured, and the slope of the voltage with respect to the current value is calculated, which is an index for knowing how much current can flow through the battery.) occured. Here, unless the initial output characteristics are improved, there is a problem that sufficient output / regeneration characteristics cannot be obtained when this type of non-aqueous electrolyte secondary battery is used as a power source for an electric vehicle or the like.
Therefore, the present invention and others have made various studies, and have found that an initial output characteristic is improved by performing an aging process that satisfies a certain condition.

  The present invention has been made based on such knowledge, and a special aging treatment is applied to a nonaqueous electrolyte secondary battery including a nonaqueous electrolyte solution to which a lithium salt having an oxalato complex as an anion is added. Thus, an object of the present invention is to provide a nonaqueous electrolyte secondary battery with improved initial output characteristics.

  The method for producing a non-aqueous electrolyte secondary battery of the present invention includes a positive electrode containing a lithium transition metal composite oxide capable of occluding and releasing lithium as a positive electrode active material, and a carbon capable of occluding and releasing lithium as a negative electrode active material After inserting the negative electrode included in the outer can into the outer can, a nonaqueous electrolytic solution to which a lithium salt having an oxalato complex as an anion is added is injected into the outer can. And in order to achieve the said objective, after injection | pouring of the non-aqueous electrolyte to which the lithium salt which uses an oxalato complex as an anion was added, the battery voltage is 1V or more in a temperature atmosphere of 35 to 85 degreeC before shipment. An aging process is allowed to be allowed to stand for 7 days (168 hours).

  Here, after injecting a non-aqueous electrolyte solution to which a lithium salt having an oxalato complex as an anion was added, the battery voltage was 1 V or more before shipment in a temperature atmosphere of 35 ° C. to 85 ° C. for 7 days (168 hours). It is clear that the initial output characteristics are improved when left alone. This is because when the battery voltage is 1 V or higher and left in a temperature atmosphere of 35 ° C. to 85 ° C., the lithium salt having an oxalato complex as an anion is reduced and decomposed, and the negative electrode surface is stable and permeable to lithium ions. It is considered that an excellent film is formed. And, by forming a film with excellent lithium ion permeability on the negative electrode surface, the internal resistance is lowered and the initial output characteristics are improved.

In this case, when the standing period exceeds 7 days (168 hours), the coating formed on the negative electrode surface becomes too thick, so that the internal resistance increases and the initial output characteristics are not improved. . For this reason, it is necessary to set the leaving period within 7 days (168 hours).
On the other hand, when the standing temperature is less than 35 ° C., the lithium salt having an oxalato complex as an anion is difficult to be decomposed, and a film excellent in lithium ion permeability is hardly formed on the negative electrode surface. On the other hand, when the leaving temperature exceeds 85 ° C., the electrolytic solution is considered to be decomposed and the battery characteristics are deteriorated. For this reason, it is desirable that the temperature left for aging be 35 ° C. or higher and 85 ° C. or lower.
Furthermore, since the oxalato complex does not decompose when the battery voltage is less than 1V, it is necessary to leave the battery voltage at 1V or more.

In addition, when adding a lithium salt having an oxalato complex as an anion, if the amount of the lithium salt having an oxalato complex as an anion is less than 0.01 mol / liter with respect to the non-aqueous solvent, it is good on the negative electrode. A film is not sufficiently formed. On the other hand, when the addition amount is more than 0.2 mol / liter with respect to the non-aqueous solvent, the coating formed on the surface of the negative electrode becomes too thick and the internal resistance increases.
For this reason, it is desirable to add the lithium salt having an oxalato complex added to the non-aqueous electrolyte as an anion in a range of 0.01 to 0.2 mol / liter with respect to the non-aqueous solvent.

The lithium salt having an oxalato complex as an anion may be a lithium salt having an anion in which C ₂ O ₄ ²⁻ is coordinated to the central atom, and Li [M (C ₂ O ₄ ) _x R _y ] (here Wherein M is a transition metal, an element selected from groups IIIb, IVb, and Vb of the periodic table, R is a group selected from halogen, an alkyl group, and a halogen-substituted alkyl group, x is a positive integer, and y is a positive integer 0 or a positive integer) is desirable, and it is preferable to use a material in which M consists of boron or phosphorus. In particular, lithium-bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) or lithium-difluoro (oxalato) borate (LiB (C ₂ O ₄ ) F ₂ ) is preferably used. This is because the complex becomes more stable in the non-aqueous electrolyte and a more stable film is formed, and it is very advantageous in terms of cost.

  In addition, as the nonaqueous solvent in the nonaqueous electrolyte, those generally used in nonaqueous electrolyte secondary batteries can be used, for example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, Chain carbonates such as dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate can be used. In particular, it is preferable to use a mixed solvent of a cyclic carbonate and a chain carbonate. In addition, it is preferable that vinylene carbonate (VC) is contained in the nonaqueous electrolytic solution because a better film is formed on the surface of the negative electrode.

  As described above, in the present invention, an aging process is provided in which the aging process is performed in a temperature atmosphere of 35C to 85C at 1 V or higher for only 7 days, so that the non-aqueous electrolyte with improved initial output characteristics is provided. A secondary battery can be obtained.

  Next, embodiments of the present invention will be described below. However, the present invention is not limited to these embodiments, and can be implemented with appropriate modifications within a range not changing the object of the present invention. is there. In addition, FIG. 1 is sectional drawing which shows typically the nonaqueous electrolyte secondary battery of this invention.

1. The positive electrode plate Li ₂ CO ₃ and (Ni _0.4 Co _0.3 Mn _0.3 ) ₃ O ₄ have a molar ratio of Li to (Ni _0.4 Co _0.3 Mn _0.3 ) of 1: 1 (Li: (Ni _0.4 Co _0.3 Mn _0.3 ). = 1: 1). Subsequently, this mixture was fired at 900 ° C. for 20 hours in an air atmosphere to obtain a lithium transition metal oxide represented by LiNi _0.4 Co _0.3 Mn _0.3 O ₂ having an average particle size of 12.1 μm, and a positive electrode active material It was.

  The positive electrode active material obtained as described above, the carbon powder as the conductive agent, and the polyvinylidene fluoride (PVdF) as the binder were N— in a mass ratio of 92: 5: 3. It was added to methyl-2-pyrrolidone (NMP) and kneaded to prepare a positive electrode slurry. The produced positive electrode slurry was applied on an aluminum foil as the positive electrode core 11a and then dried to form the positive electrode active material layer 11b. Then, it rolled until it became a predetermined packing density using the rolling roll, and after cut | disconnecting to the predetermined dimension, the positive electrode current collection tab 11c was attached and the positive electrode plate 11 was produced.

2. Negative electrode plate A negative electrode slurry was prepared by kneading artificial graphite as a negative electrode active material and an aqueous solution in which polyimide (PI) as a binder was dissolved. In this case, these were added so that the negative electrode active material: binder mass ratio was 97: 3. Next, the prepared negative electrode slurry was applied on a copper foil as the negative electrode core 12a and then dried to form a negative electrode active material layer 12b. Then, it rolled until it became a predetermined filling density using the rolling roller, the negative electrode current collection tab 12c was attached, and the negative electrode plate 12 was produced.

3. Non-aqueous electrolyte In preparing a non-aqueous electrolyte, a mixed solvent in which ethylene carbonate (EC), a cyclic carbonate, and ethyl methyl carbonate (EMC), a chain carbonate, were mixed at a volume ratio of 3: 7. In contrast, lithium hexafluorophosphate (LiPF ₆ ) as a solute was dissolved at a rate of 1 mol / liter, and 0.1 mol of lithium-bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) was dissolved. / L was dissolved at a rate of 1 liter. Only 1% by mass of vinylene carbonate (VC) was added to the solution thus obtained to prepare a nonaqueous electrolytic solution, which was designated as electrolytic solution a.

On the other hand, lithium hexafluorophosphate (LiPF ₆ ) is dissolved as a solute at a rate of 1 mol / liter in a mixed solvent similar to the above, and lithium-difluoro (oxalato) borate (LiB (C ₂ O ₄ ) 1% by mass of vinylene carbonate (VC) was added to a solution in which F ₂ ) was dissolved at a rate of 0.1 mol / liter to prepare a nonaqueous electrolytic solution, which was designated as electrolytic solution b.

4). Non-aqueous electrolyte secondary battery Next, each positive electrode plate 11 manufactured as described above and the negative electrode plate 12 manufactured as described above were used, respectively, and a separator 13 made of a polypropylene microporous film was interposed therebetween. After laminating, they were wound in a spiral shape to form a spiral electrode group. Next, after inserting these spiral electrode groups into a cylindrical metal outer can 14 in which an upper outer periphery is drawn to form a drawn portion 14a, a negative electrode current collecting tab 12c extending from the negative electrode plate 12 is provided. It welded to the inner bottom face of the metal outer can 14. On the other hand, a positive electrode current collecting tab 11 c extending from the positive electrode plate 11 was welded to the bottom surface of the positive electrode lid 15 b of the sealing body 15, and a ring-shaped insulating gasket 16 was disposed on the outer periphery of the sealing body 15.

  A cap-like positive electrode terminal 15a is disposed on the upper portion of the positive electrode lid 15b, and a valve for sealing an exhaust hole 15c formed at the center of the positive electrode lid 15b in the cap-like positive electrode terminal 15a. A valve body including a plate 15d and a spring 15e that presses the plate 15d is disposed. Subsequently, the non-aqueous electrolyte (a, b) prepared as described above was injected into the metal outer can 14. Thereafter, after the sealing body 15 having the ring-shaped insulating gasket 16 disposed on the outer peripheral portion is disposed on the narrowed portion 14a formed on the upper outer periphery of the metal outer can 14, the upper end of the metal outer can 14 is disposed. The portion 14b was caulked and sealed to the sealing body 15 side. Thereby, non-aqueous electrolyte secondary batteries 10 (A, B) having a design capacity of 5 Ah were produced. In addition, the thing using the electrolyte solution a was made into the battery A, and the thing using the electrolyte solution b was made into the battery B.

4). Aging Next, using the batteries A and B produced as described above, each of the batteries A and B is expressed as 1 It (It is expressed in rated capacity (mA) / 1 h (hours) at room temperature of 25 ° C. The battery was charged to 4.1 V with a charging current of (numerical value). The batteries A and B after being charged in this way were left in a constant temperature bath at 60 ° C. for aging. In this case, the battery A left in a constant temperature bath at 60 ° C. for 5 hours is designated as battery A1, the battery left for 10 hours is designated as battery A2, and the battery left for 24 hours is designated as battery A3. The battery that was left alone was designated as battery A4, the battery that was left alone for 7 days (168 hours) was designated as battery A5, and the battery that was left alone for 14 days (336 hours) was designated as battery A6. A battery B1 left in a constant temperature bath at 60 ° C. for 48 hours is designated as battery B1, a battery left for 7 days (168 hours) as battery B2, and a battery left for 14 days (336 hours). Battery B3 was obtained. The battery A that was not aged was designated as battery A0, and the battery B that was not aged was designated as battery B0.

5). Battery characteristics test Next, the batteries A0 and B0 that were not aged were charged to 4.1 V with a charging current of 1 It at a room temperature of 25 ° C., respectively, and then the charging current was maintained while maintaining the voltage at 4.1 V. The battery was charged so that the total charge time was 1.5 hours, and then discharged to 3.0 V with a discharge current of 0.1 It, and the discharge capacity before aging was measured. The batteries A0 and B0 were charged at a current of 1 It, 3 It, 5 It, 10 It, and 15 It, respectively, at a room temperature of 25 ° C. until the depth of charge (SOC) reached 50% with a charging current of 1 It. Charging and discharging for 2 seconds, measuring each battery voltage, plotting each current value and battery voltage to obtain the IV characteristics during charging and discharging, and charging and discharging from the slope of the obtained straight line When the IV resistance (mΩ) before aging at the time was obtained, the results shown in Table 1 below were obtained.

  On the other hand, using the batteries A1 to A6 and the batteries B1 to B3 which have been aged as described above, the batteries A1 to A6 and the batteries B1 to B3 are respectively charged at a room temperature of 25 ° C. with a charging current of 1 It. After charging to 1V, the charging current is further reduced while maintaining the voltage at 4.1V, and charging is performed so that the total charging time is 1.5 hours. The discharge capacity after aging was measured.

In addition, the batteries A1 to A6 and the batteries B1 to B3 were charged at a charging current of 1 It at a room temperature of 25 ° C. until the depth of charge (SOC) reached 50%, respectively, 1/3 It, 1 It, 3 It, And charging and discharging at a current of 5 It for 10 seconds, measuring each battery voltage, plotting each current value and the battery voltage, obtaining the IV characteristics at the time of charging and discharging, and obtaining the straight line obtained When the IV resistance (mΩ) after aging during charging and discharging was determined from the slope, the results shown in Table 1 below were obtained.

As is clear from the results in Table 1 above, in the battery provided with the non-aqueous electrolyte to which LiB (C ₂ O ₄ ) ₂ was added, the battery voltage was 4.1 V and the temperature was 60 ° C. for 7 days. The batteries A1 to A5 that have been aged within (168 hours) have both lower IV resistance during discharging and IV resistance during charging than the battery A0 that has not been aged, resulting in lower internal resistance. I understand. Moreover, even in a battery equipped with a non-aqueous electrolyte to which LiB (C ₂ O ₄ ) F ₂ is added, aging within 7 days (168 hours) in a temperature atmosphere of 60 ° C. with a battery voltage of 4.1V. It can also be seen that the batteries B1 and B2 that were performed had lower internal resistance due to the lower IV resistance during discharging and IV resistance during charging than the battery B0 that did not undergo aging.

This is because LiB (C ₂ O ₄ ) ₂ or LiB added to the non-aqueous electrolyte is left in a temperature atmosphere of 60 ° C. for a period of 7 days (168 hours) in a state where the battery voltage is 4.1V. The lithium salt having an oxalato complex such as (C ₂ O ₄ ) F ₂ as an anion is reduced, and a stable and excellent lithium ion permeability film is formed on the negative electrode surface, resulting in a low internal resistance. It is thought.

On the other hand, the battery A6 and the battery B3, which have been left for 14 days (336 hours), on the contrary, have both an increased IV resistance during discharging and an IV resistance during charging, as compared to the battery B0 that has not been aged. You can see that it has become higher. This is presumably because when the standing time was too long, the coating formed on the negative electrode surface became too thick, and both the IV resistance during discharging and the IV resistance during charging increased, and the internal resistance increased.
From these facts, it can be seen that it is desirable that the standing time for aging is within 7 days (168 hours).

6). Examination of aging temperature Next, lithium hexafluorophosphate (LiPF ₆ ) was used as a solute for a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 7. Was dissolved at a rate of 1 mol / liter, and lithium-bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) was dissolved at a rate of 0.1 mol / liter. A non-aqueous electrolyte was prepared by adding 1% by mass of vinylene carbonate (VC) to 99% by mass of the solution thus obtained, and this was designated as electrolyte c.

  Next, a spiral electrode group is formed using the positive electrode plate 11, the negative electrode plate 12, and the separator 13 manufactured as described above, and this is inserted into a cylindrical metal outer can 14. The nonaqueous electrolyte secondary battery 10 was produced in the same manner as described above, and this was designated as battery C. Next, the battery C is charged to 4.1 V with a charging current of 1.4 A at a room temperature of 25 ° C. and then charged, and this is left in a constant temperature bath at a predetermined temperature for a predetermined time. Aging was performed. In this case, the battery C1 was left in a 45 ° C. constant temperature bath for 13 hours, the battery C2 was left in the 60 ° C. constant temperature bath for 13 hours, and was left in the 60 ° C. constant temperature bath for 24 hours. This was designated as Battery C3. In addition, the battery C0 was not subjected to aging.

Then, using the battery C0 that was not aged, the discharge capacity before aging was measured in the same manner as described above, and the IV resistance (mΩ) before aging was obtained, and the results shown in Table 2 below were obtained. It was. Further, using the aged batteries C1 to C3, the discharge capacity after aging was measured in the same manner as described above, and the IV resistance (mΩ) after aging was obtained. As a result, the results shown in Table 2 below were obtained. became.

  As is apparent from the results in Table 2, the batteries C1 to C3 subjected to aging have both lower IV resistance during discharging and IV resistance during charging and lower internal resistance than the battery C0 not subjected to aging. You can see that In this case, the aging at 60 ° C is lower than the aging at 45 ° C, and the IV resistance during discharging and the IV resistance during charging are further lowered. Therefore, the standing temperature for aging should be as high as possible. I understand that.

However, when the temperature to be left exceeds 85 ° C., the electrolytic solution is considered to be decomposed and the battery characteristics are deteriorated. On the other hand, when the standing temperature is less than 35 ° C., the lithium salt having an oxalato complex as an anion is difficult to be decomposed, and a film excellent in lithium ion permeability is hardly formed on the negative electrode surface.
From this, it can be said that the temperature left for aging is preferably 35 ° C. or more and 85 ° C. or less.
Note that when the battery voltage is less than 1 V, the oxalato complex does not decompose, so it is desirable to leave the battery at 1 V or more, preferably 1.5 V or more of the voltage at which the oxalato complex decomposes.

In the above-described embodiment, lithium-bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) or lithium-difluoro (oxalato) borate (LiB (C ₂ ) is used as a lithium salt having an oxalato complex as an anion. Although examples using O ₄ ) F ₂ ) have been described, the present invention is not limited thereto, and any lithium salt having an anion in which C ₂ O ₄ ²⁻ is coordinated to the central atom may be used. In this case, Li [M (C ₂ O ₄ ) _x R _y ] (where M is a transition metal, an element selected from groups IIIb, IVb, and Vb of the periodic table, R is a halogen, an alkyl group, A group selected from halogen-substituted alkyl groups, x is a positive integer, y is 0 or a positive integer), and preferably, M is a group consisting of boron or phosphorus. Is preferred.

In the above-described embodiment, the example in which the addition amount of the lithium salt having the oxalato complex as the anion is dissolved at a rate of 0.1 mol / liter with respect to the non-aqueous solvent has been described. The addition amount of the lithium salt is not limited to this, but may be added in the range of 0.01 to 0.2 mol / liter with respect to the non-aqueous solvent. Further, also, the oxalate complex as another lithium salt of lithium salt having an anion, an example has been described using a lithium hexafluorophosphate (LiPF _6), without being limited thereto, LiAsF _6, LiBF _{4, LiCF 3 SO 3, LiN (C} l F 2l + 1 SO 2) (C m F 2m + 1 SO 2) (l, m is an integer of 1 or _{more), LiC (C P F 2P} + 1 SO 2) (C _q F _{2q + 1} SO ₂ ) (C _r F _{2r + 1} SO ₂ ) (p, q, and r are integers of 1 or more), etc. may be used, and these solutes are used in one kind. Alternatively, two or more types may be used in combination.

Furthermore, in the above-described embodiment, Li ₂ CO ₃ and (Ni _0.4 Co _0.3 Mn _0.3 ) _{3 are} used as starting materials when synthesizing Li ₂ (Ni _0.4 Co _0.3 Mn _0.3 ) O ₂ as the positive electrode active material. Although O ₄ is used, the present invention is not limited to these. For example, LiOH, Li ₂ CO ₃ or the like may be used as a raw material for Li, and Ni _0.4 Co _0.3 Mn may be used as a raw material for NiCoMn. _0.3 (OH) ₂ or the like may be used.

It is sectional drawing which shows typically the nonaqueous electrolyte secondary battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Non-aqueous electrolyte secondary battery, 11 ... Positive electrode plate, 11a ... Positive electrode core, 11b ... Positive electrode mixture layer, 11c ... Positive electrode current collection tab, 12 ... Negative electrode plate, 12a ... Negative electrode core, 12b ... Negative electrode mixture Layer, 12c ... negative electrode current collecting tab, 13 ... separator, 14 ... metal outer can, 14a ... throttle part, 15 ... sealing body, 15a ... positive electrode terminal, 15b ... positive electrode lid, 15c ... exhaust hole 15d ... valve plate, 15e ... Spring, 16 ... Insulating gasket

Claims (5)

After inserting a positive electrode containing a lithium transition metal composite oxide capable of occluding and releasing lithium as a positive electrode active material and a negative electrode containing carbon capable of occluding and releasing lithium as a negative electrode active material, A method for producing a non-aqueous electrolyte secondary battery formed by injecting a non-aqueous electrolyte solution to which a lithium salt having an oxalato complex as an anion is added in an outer can,
An aging step in which a battery voltage is 1 V or higher and the product is left in a temperature atmosphere of 35 ° C. to 85 ° C. within 7 days after the injection of a non-aqueous electrolyte solution to which a lithium salt having an oxalato complex as an anion is added. A method for producing a non-aqueous electrolyte secondary battery, wherein:   The method for producing a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium salt having the oxalato complex as an anion is added in an amount of 0.01 to 0.2 mol / liter with respect to the solvent. The lithium salt having the oxalato complex as an anion is lithium-bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) or lithium-difluoro (oxalato) borate (LiB (C ₂ O ₄ ) F ₂ ). The method for producing a non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte secondary battery is produced.   4. The non-aqueous electrolyte 2 according to claim 1, wherein a lithium salt is contained as a solute in the non-aqueous electrolyte in addition to a lithium salt having an oxalato complex as an anion. A method for manufacturing a secondary battery. The said nonaqueous electrolyte contains vinylene carbonate, The manufacturing method of the nonaqueous electrolyte secondary battery in any one of Claims 1-4 characterized by the above-mentioned.

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