JP6110287B2 - Nonaqueous electrolyte secondary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery and a method for manufacturing the same. Specifically, the present invention relates to a non-aqueous electrolyte secondary battery capable of exhibiting high output even in a low SOC region and a method for manufacturing the same.

  Lithium ion secondary batteries and other secondary batteries are smaller, lighter, and have higher energy density and superior output density than existing batteries. For this reason, in recent years, it is preferably used as a power source for driving vehicles such as hybrid vehicles and electric vehicles. This type of secondary battery includes positive and negative electrodes capable of reversibly occluding and releasing chemical species (for example, lithium ions in the case of a lithium ion secondary battery), and an electrolyte interposed between the two electrodes. And charge / discharge is performed by the charge carriers in the electrolyte moving between the two electrodes. As a typical example of an electrolyte used for this type of secondary battery, a liquid electrolyte containing a supporting salt (for example, a lithium salt in the case of a lithium ion secondary battery) in a non-aqueous solvent (hereinafter referred to as a non-aqueous electrolyte). Is mentioned. For example, a typical example of the lithium salt (supporting salt) is a lithium salt containing fluorine as a constituent element, such as lithium hexafluorophosphate. Patent Document 1 describes a technology relating to a lithium ion secondary battery using such a lithium salt and a non-aqueous solvent.

JP2013-030497A

  By the way, the supporting salt (for example, lithium salt) having fluorine as a constituent element as described above can be decomposed to generate hydrogen fluoride (HF) when it reacts with water. HF is highly corrosive to metals and inorganic oxides, and when HF is generated in a battery, it may be a factor that increases the internal resistance by corroding the current collector. Therefore, in a secondary battery using such a non-aqueous electrolyte, it is important to reduce the amount of moisture in the battery and suppress the generation of HF. For example, Patent Document 1 describes that by reducing the moisture content of the separator, the amount of moisture brought into the battery can be reduced, and defects caused by HF can be suppressed.

  However, according to the study of the present inventor, if the moisture content in the battery is reduced as described above, the generation of HF can be suppressed, but the output characteristics in the low SOC (State of Chrage) region are reduced. There may be cases. It is desirable that a battery mounted on a vehicle whose wheels are driven by an electric motor such as a hybrid vehicle (particularly a plug-in hybrid vehicle) or an electric vehicle stably exhibits a required output even in a low SOC range. This invention is made | formed in view of this point, The place made into the objective is providing the nonaqueous electrolyte secondary battery which can exhibit a high output stably also in a low SOC area | region. Another object is to provide a suitable method for producing such a high-performance nonaqueous electrolyte secondary battery.

  The present inventor has come up with the idea that the output characteristics in the low SOC region can be improved by adding a desired amount of moisture in the battery, and further by adding a P-oxalato compound to the non-aqueous electrolyte. The inventors have found that the output characteristics in the low SOC region can be effectively improved without increasing the battery resistance even when moisture-derived HF occurs, and the present invention has been completed.

That is, the non-aqueous electrolyte secondary battery provided by the present invention includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. The non-aqueous electrolyte is a compound represented by the general formula (I): A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ (hereinafter sometimes simply referred to as “P-oxalato compound”). Where the total amount of water contained in the battery is W1 and the amount of the compound in the non-aqueous electrolyte solution is W2 per 1 Ah capacity of the battery, and 4.15 mg / Ah. ≦ W1, 20 mg / Ah ≦ W2, 2.25 ≦ W2 / W1 are satisfied. In the formula (I), A ⁺ is an alkali metal cation, X is a halogen atom, and n is 1 or 2 or 3.

  In the non-aqueous electrolyte secondary battery having such a configuration, the total amount W1 of moisture contained in the battery (hereinafter also referred to as the moisture amount W1 in the battery) is set to be 4.15 mg / Ah or more. As a result, the output characteristics in the low SOC region (for example, SOC is 30% or less) can be improved as compared with the conventional battery in which the water content W1 in the battery is lower than 4.15 mg / Ah. Further, since the predetermined amount of the P-oxalato compound is contained in the non-aqueous electrolyte, even if the water content W1 in the battery is increased, a situation in which the battery resistance increases due to the HF derived from the moisture occurs. hard. Therefore, such a non-aqueous electrolyte secondary battery can stably exhibit high output even in a low SOC region while maintaining good battery performance (low resistance).

  The non-aqueous electrolyte secondary battery disclosed herein preferably has a P-oxalato compound amount W2 satisfying 20 mg / Ah ≦ W2, more preferably satisfying 40 mg / Ah ≦ W2. Those satisfying 60 mg / Ah ≦ W2 are particularly preferable. If the addition amount W2 of the P-oxalato compound is too small, the battery performance improvement effect (typically resistance increase suppressing effect) due to the addition of the P-oxalato compound may be insufficient. On the other hand, when there is too much addition amount W2 of a P-oxalato compound, since there exists a possibility that the reaction resistance in low temperature (for example, -30 degrees C or less) may raise, it is unpreferable. From the viewpoint of reducing reaction resistance at low temperatures, W2 ≦ 500 mg / Ah is generally satisfied, W2 ≦ 405 mg / Ah is preferable, and W2 ≦ 300 mg / Ah is particularly preferable.

  In the non-aqueous electrolyte secondary battery disclosed herein, the water content W1 in the battery preferably satisfies 7.14 mg / Ah ≦ W1, more preferably satisfies 10 mg / Ah ≦ W1, and 30 mg. Those satisfying / Ah ≦ W1 are particularly preferable. If the water content W1 in the battery is too small, the required output characteristics may not be obtained in the low SOC range. On the other hand, a battery with too much water content W1 in the battery is not preferable because the effect of improving the output characteristics in the low SOC region is dulled and the battery resistance (particularly positive electrode resistance) tends to increase. From the viewpoint of suppressing increase in resistance, W1 ≦ 60 mg / Ah is generally satisfied, preferably W1 ≦ 50 mg / Ah, and particularly preferably W1 ≦ 40 mg / Ah.

  In the non-aqueous electrolyte secondary battery disclosed herein, the ratio value (W2 / W1) of the amount W2 of the P-oxalato compound to the water content W1 in the battery satisfies 3 ≦ W2 / W1. preferable. According to this configuration, since the ratio between the water content W1 in the battery and the amount W2 of the P-oxalato compound is in an appropriate balance, the above-described effects can be better exhibited. Furthermore, the durability performance of the battery can be effectively improved, and the capacity retention rate after storage at a high temperature (for example, 60 ° C.) can be improved. The ratio (W2 / W1) preferably satisfies 2.25 ≦ W2 / W1 ≦ 30, more preferably 3 ≦ W2 / W1 ≦ 30, and more preferably 5 ≦ W2 / W1 ≦. It is particularly preferable to satisfy 20.

Moreover, this invention provides the method of manufacturing suitably the nonaqueous electrolyte secondary battery as mentioned above. That is, the manufacturing method of the present invention is a method of manufacturing a non-aqueous electrolyte secondary battery including an electrode body including a positive electrode, a negative electrode, and a separator, and a non-aqueous electrolyte solution: the electrode body and the non-aqueous battery. The step of preparing an electrolytic solution, wherein the non-aqueous electrolytic solution has the following general formula (I): A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ (in formula (I), A ⁺ Is an alkali metal cation, X is a halogen atom, and n is 1 or 2 or 3.); The prepared electrode body and the non-aqueous electrolysis A step of accommodating the liquid in a battery case, wherein the total amount of moisture contained in the electrode body (ie, positive electrode, negative electrode and separator) and the non-aqueous electrolyte is W1, and the P-oxalato in the non-aqueous electrolyte When the amount of the compound is W2, 4.1 A relationship of 5 mg / Ah ≦ W1, 20 mg / Ah ≦ W2, 2.25 ≦ W2 / W1 is established; and a step of performing an initial charge / discharge process on the electrode body accommodated in the battery case. To do. This manufacturing method can be suitably employed, for example, as a method for manufacturing any of the nonaqueous electrolyte secondary batteries disclosed herein.

  In a preferred embodiment of the method for producing a non-aqueous electrolyte secondary battery disclosed herein, the total amount W1 of water satisfies 7.14 (mg / Ah) ≦ W1. Further, the amount W2 of the compound satisfies W2 ≦ 500 (mg / Ah). Further, the W2 / W1 satisfies 3 ≦ W2 / W1.

It is a figure which shows typically the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a figure which shows typically the wound electrode body internally equipped with a lithium ion secondary battery. It is a graph which shows the relationship between the moisture content in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the moisture content in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the amount of LPFO / the amount of moisture in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the amount of LPFO / the amount of moisture in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the amount of LPFO / the amount of moisture in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the amount of LPFO / the amount of moisture in a battery, IV resistance, and resistance increase rate. It is a graph which shows the relationship between the amount of LPFO and -30 degreeC reaction resistance. It is a graph which shows the relationship between the amount of LPFO / the amount of moisture in the battery and the capacity retention rate after high temperature storage.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  In the present specification, the term “secondary battery” refers to a power storage device that can be repeatedly charged and discharged, and a so-called storage battery such as a lithium secondary battery, nickel hydride battery, or nickel cadmium battery, and a power storage element such as an electric double layer capacitor. It is a term encompassing. The “non-aqueous electrolyte secondary battery” refers to a secondary battery including a non-aqueous electrolyte (typically, an electrolyte containing a supporting salt (supporting electrolyte) in a non-aqueous solvent). The “lithium secondary battery” refers to a secondary battery that uses lithium ions as electrolyte ions and is charged and discharged by the movement of lithium ions between the positive and negative electrodes. A secondary battery generally referred to as a lithium ion battery is a typical example included in the lithium secondary battery in this specification. The electrode active material refers to a material capable of reversibly occluding and releasing a chemical species (lithium ion in a lithium ion secondary battery) serving as a charge carrier.

  The technology disclosed herein can be widely applied to non-aqueous electrolyte secondary batteries including an electrode body composed of a positive electrode, a negative electrode, and a separator, and a non-aqueous electrolyte. The external shape of the secondary battery can be appropriately changed according to the application, and is not particularly limited. For example, the external shape may be a rectangular parallelepiped shape, a flat shape, a cylindrical shape, or the like. In addition, the shape of the electrode body is not particularly limited because it may vary depending on the shape of the secondary battery. For example, an electrode body (rolled electrode body) formed by winding a sheet-like positive electrode and a negative electrode together with a sheet-like separator can be preferably used. Hereinafter, the case of a lithium ion secondary battery may be described in more detail as a typical example, but the application target of the present invention is not intended to be limited to such a battery.

<Moisture content in the battery>
The lithium ion secondary battery disclosed here includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. The nonaqueous electrolytic solution contains at least a nonaqueous solvent and a P-oxalato compound described later. Here, when the total amount of moisture contained in the battery is W1 and the amount of the P-oxalato compound in the non-aqueous electrolyte solution is W2, per battery capacity 1 Ah, 4.15 mg / Ah ≦ W1, 20 mg / The relationship of Ah ≦ W2, 2.25 ≦ W2 / W1 is established.

  Here, the total amount W1 of moisture contained in the battery may be calculated based on the amount of moisture contained in each member (typically positive electrode, negative electrode, separator, non-aqueous electrolyte) constituting the battery. Since the lithium ion secondary battery to which the technology disclosed herein is applied is assembled in a highly dry environment, the mixing of moisture from the environment has almost no effect. For this reason, the entry of moisture into the battery is mainly brought about by members constituting the battery (typically, a positive electrode, a negative electrode, a separator, a non-aqueous electrolyte). Therefore, the total amount W1 of water that can be mixed into the battery from these members may be obtained, for example, by grasping the water amount of each member in the amount used for battery manufacture and adding them up. The amount of water in each member is typically calculated from the value obtained by quantifying the amount of water present (attached, dissolved, etc.) in each member. As a method for quantifying the water content of each member, a method capable of quantifying a trace amount of water can be arbitrarily used. For example, the Karl Fischer method can be preferably employed. For example, samples are taken from each member of the positive electrode sheet, negative electrode sheet, separator, and non-aqueous electrolyte, and the moisture content in the sample is quantified with a moisture meter (Karl Fischer moisture meter, etc.), and the value is included in each member. It is good to obtain the amount of water (mg) to be removed.

  The amount of water in each member (typically positive electrode, negative electrode, separator, non-aqueous electrolyte) is determined by exposing each member to a high moisture concentration (typically an environment maintained at a predetermined dew point temperature) for a predetermined time. Can be adjusted arbitrarily. For example, it may be adjusted by performing a part or all of various operations from the production of each member to the battery sealing in a processing chamber (room, box, chamber) maintained at a predetermined dew point temperature. The dew point temperature may vary depending on the material and amount of each member, but is generally from −50 ° C. to 0 ° C., and preferably from −30 ° C. to −10 ° C. Alternatively, the water content of each member may be adjusted by adding an appropriate amount of water to each member (typically positive electrode, negative electrode, separator, non-aqueous electrolyte). For example, water may be added to each member (for example, the positive electrode active material layer of the positive electrode or the negative electrode active material layer of the negative electrode) so as to satisfy the moisture content W1 in the battery and accommodated in the battery case.

  It should be noted that the amount of water can be similarly determined for members other than the above members (for example, battery cases and electrode terminals). However, when the surface area of other members such as a battery case and a terminal is extremely small with respect to the surface area of the member (positive electrode, negative electrode, separator), for example, as in the above-described wound electrode body, It is better to omit the addition to the total amount of moisture, assuming that the amount of moisture has little effect. Similarly, the amount of water adsorbed on the current collector exposed portion of each electrode sheet can usually be ignored.

  The lithium ion secondary battery disclosed herein preferably has a total water content W1 satisfying 4.15 mg / Ah, more preferably 7.14 mg / Ah ≦ W1. Those satisfying 10 mg / Ah ≦ W1 are more preferable, and those satisfying 15 mg / Ah ≦ W1 (for example, 30 mg / Ah ≦ W1) are particularly preferable. Thus, by including a predetermined amount of moisture in the battery, output characteristics in a low SOC region (for example, a region of SOC 30% or less) can be improved. On the other hand, a battery in which the total amount W1 of water is too large is not preferable because the effect of improving the output characteristics in the low SOC region is dulled and the battery resistance (particularly positive electrode resistance) tends to increase. From the viewpoint of suppressing an increase in resistance, W1 ≦ 60 mg / Ah is generally satisfied, preferably W1 ≦ 50 mg / Ah, and particularly preferably W1 ≦ 40 mg / Ah.

  Here, when the moisture content W1 in the battery is increased, HF is generated due to a reaction between the moisture and a supporting salt (for example, a lithium salt) of the electrolytic solution, and the positive electrode is corroded by the HF. It can be an increase factor. However, in the technique disclosed here, since the non-aqueous electrolyte contains a P-oxalato compound, an increase in battery resistance can be suppressed even when a large amount of moisture is added.

<P-oxalato compound>
The P-oxalato compound is a compound represented by the general formula (I): A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ , and in the formula (I), A ⁺ represents Li, It is a cation of an alkali metal such as Na or K. In a preferred embodiment, A ⁺ is a lithium cation (Li ⁺ ). X is a halogen atom such as F, Cl, or Br. In a preferred embodiment, X is a fluorine atom (F). N is 1 or 2 or 3. In a preferred embodiment, n = 2. In other words, as the P-oxalato compound, a compound represented by the general formula: A ⁺ [PX ₄ (C ₂ O ₄ ) ₂ ] ⁻ (wherein A ⁺ and n are the same as those in the general formula (I)). Is preferably used.

The P-oxalato compound is an oxalato complex compound having a structural portion in which at least one oxalate ion (C ₂ O ₄ ²⁻ ) is coordinated to phosphorus (P). By including a P-oxalato compound in the non-aqueous electrolyte, it is presumed that a reaction between the P-oxalato compound and HF occurs, and an increase in resistance of the positive electrode due to HF is suppressed. Specific examples include lithium difluorobis (oxalato) phosphate (Li ⁺ [PF ₂ (C ₂ O ₄ ) ₂ ] ⁻ ) represented by the following formula (II). In a preferred embodiment, lithium difluorobis (oxalato) phosphate represented by the above formula (II) is mainly used (that is, 50 mol% or more). Among them, it is preferable to use lithium difluorobis (oxalato) phosphate in an amount of 70 mol% or more (typically 80 mol% or more, for example, 90 mol% or more), and P consisting essentially of lithium difluorobis (oxalato) phosphate. It is particularly preferred to use an oxalato compound.

  The amount W2 of the P-oxalato compound added is preferably 20 mg or more per 1 Ah of battery capacity, more preferably 40 mg / Ah ≦ W2, and particularly preferably 60 mg / Ah ≦ W2. If the addition amount W2 of the P-oxalato compound is too small, the battery performance improvement effect (typically the resistance increase suppressing effect) due to the addition of the P-oxalato compound may be insufficient. On the other hand, if the addition amount W2 of the P-oxalato compound is too large, the addition amount W2 of the P-oxalato compound increases and the cost becomes high, and the P-oxalato compound itself can be a resistance component. The reaction resistance at 30 ° C. may increase. From the viewpoint of reducing reaction resistance at low temperatures, W2 ≦ 500 mg / Ah is generally satisfied, preferably W2 ≦ 450 mg / Ah (for example, W2 ≦ 405 mg / Ah), and particularly preferably W2 ≦ 300 mg / Ah.

  In the preferred technique disclosed herein, it is preferable that the ratio value (W2 / W1) of the amount W2 of the P-oxalato compound to the total amount W1 of water in the battery satisfies 3 ≦ W2 / W1. According to such a configuration, since the ratio between the amount of water W1 in the battery and the amount W2 of the P-oxalato compound is in an appropriate balance, the above-described effects can be better exhibited. Further, the durability performance of the battery can be effectively improved, and the capacity retention rate after storage at a high temperature (for example, 60 ° C.) can be improved. The value of the ratio (W2 / W1) generally preferably satisfies 2.25 ≦ W2 / W1, more preferably satisfies 3 ≦ W2 / W1, and more preferably satisfies 5 ≦ W2 / W1. Particularly preferred. On the other hand, a battery having an excessively large ratio (W2 / W1) increases the amount of added P2 of the P-oxalato compound and increases the cost, and suppresses the increase in resistance caused by moisture-derived HF. There is not much merit because it slows down. For example, a lithium ion secondary battery in which the value of the ratio (W2 / W1) satisfies 2.25 ≦ W2 / W1 ≦ 30 (preferably 3 ≦ W2 / W1 ≦ 20) is appropriate.

The nonaqueous electrolytic solution disclosed here contains a fluorine-containing lithium salt as a supporting salt in a nonaqueous solvent. Specific examples of such supporting _{salt, LiPF 6, LiBF 4, LiAsF} 6, etc. LiSbF ₆ and the like. These lithium salts are preferable because they have relatively high lithium ion conductivity. Among these, LiPF ₆ and LiBF ₄ can be preferably used. The concentration of the supporting salt in the electrolytic solution is not particularly limited, and may be about the same as the concentration of the electrolytic solution used in a conventional lithium ion secondary battery, for example. Usually, a nonaqueous electrolytic solution containing a supporting salt at a concentration of about 0.1 mol / L to 5 mol / L (for example, about 0.8 mol / L to 1.5 mol / L) can be preferably used.

  As the non-aqueous solvent used in the non-aqueous electrolyte, aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones and lactones can be preferably used. For example, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), 1,2-dimethoxyethane (DME), 1,2-diethoxyethane , Tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, propionitrile, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, γ-butyrolactone (BL), etc. Are exemplified. These organic solvents can be used alone or in combination of two or more.

  Even if the lithium ion secondary battery disclosed herein has a structure containing a predetermined amount of moisture at the time of battery construction (assembly), as described above, the moisture does not support the electrolyte supporting salt. Some or all of the water is consumed by the reaction. In addition, even when the non-aqueous electrolyte has a composition containing a P-oxalato compound at the time of battery construction (assembly), the P-oxalato compound reacts with HF derived from moisture as described above. -Part or all of the oxalato compound is consumed. Further, the P-oxalato compound is decomposed together with the electrolytic solution components (non-aqueous solvent, supporting salt, etc.) at the time of initial charge / discharge, etc., and a film composed of these decomposition products is formed on the electrode (positive electrode and / or negative electrode) surface. May form. Therefore, a part of P-oxalato compound may decompose | disassemble by initial stage charging / discharging or subsequent charging / discharging.

  In the battery in this state, each member (positive electrode, negative electrode, separator, and non-aqueous electrolyte) used at the time of battery construction contained moisture and a P-oxalato compound. For example, NMR (Nuclear) of the electrolyte or electrode Magnetic Resonance (nuclear magnetic resonance) analysis and mass spectrometry (for example, analysis by gas chromatography (GC), inductively coupled plasma (ICP), ion chromatography (Ion Chromatography: IC))) obtain. Furthermore, from the battery after the initial charge and discharge (or after further charge and discharge), as a method of grasping each amount of moisture and P-oxalato compound contained in each member used at the time of battery construction, for example, Examples include NMR analysis and mass spectrometry of each member (electrolytic solution, electrode, etc.) constituting the battery.

According to the technology disclosed herein, a method for manufacturing a non-aqueous electrolyte secondary battery including an electrode body including a positive electrode, a negative electrode, and a separator, and a non-aqueous electrolyte solution:
The step of preparing the electrode body and the non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution has the following general formula (I)
A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ (I)
(In the formula (I), A ⁺ is an alkali metal cation, X is a halogen atom, and n is 1 or 2 or 3).
The step of accommodating the prepared electrode body and the non-aqueous electrolyte in a battery case, where the total amount of water contained in the electrode body (ie, positive electrode, negative electrode and separator) and the non-aqueous electrolyte is W1, When the amount of the P-oxalato compound in the non-aqueous electrolyte is W2, the following (1) to (3):
(1) 4.15 mg / Ah ≦ W1
(2) 20 mg / Ah ≦ W2
(3) 2.25 ≦ W2 / W1
And the first charge / discharge process for the electrode body (battery assembly) housed in the battery case;
A method for manufacturing a non-aqueous electrolyte secondary battery can be provided.
In the first charge / discharge treatment, typically, an external power source is connected between the positive electrode (positive electrode terminal) and the negative electrode (negative electrode terminal) of the assembly, and charging is performed to a predetermined voltage range (typically constant current). Charging) and discharging. The charge / discharge treatment may be performed once but may be repeated twice or more.

  According to such a production method, by containing a P-oxalato compound satisfying the above relationships (1) to (3) in the nonaqueous electrolytic solution, the moisture in the battery reacts with the supporting salt (for example, a lithium salt) to generate HF. However, it is difficult for the HF to increase the positive electrode resistance. Therefore, it is possible to manufacture a highly reliable nonaqueous electrolyte secondary battery in which an increase in resistance is suppressed while exhibiting a high output in a low SOC region.

  Although not intended to be particularly limited, an embodiment of the lithium ion secondary battery provided with the above-described wound electrode body will be described more specifically with reference to the schematic diagrams shown in FIGS. To do. The battery structure is not limited to the illustrated example, and is not particularly limited to a prismatic battery.

  FIG. 1 is a cross-sectional view of a lithium ion secondary battery 100 according to an embodiment of the present invention. FIG. 2 is a view showing a wound electrode body 200 housed in the lithium ion secondary battery 100.

  A lithium ion secondary battery 100 according to an embodiment of the present invention is configured in a flat rectangular battery case (that is, an exterior container) 300 as shown in FIG. As shown in FIG. 2, in the lithium ion secondary battery 100, a flat wound electrode body 200 is housed in a battery case 300 together with a non-aqueous electrolyte 90.

  The battery case 300 has a box-shaped (that is, bottomed rectangular parallelepiped) case main body 320 having an opening at one end (corresponding to the upper end in a normal use state of the battery 100), and is attached to the opening. And a lid 340 made of a rectangular plate member that closes the opening.

  The material of the battery case 300 may be the same as that used in the conventional lithium ion secondary battery, and is not particularly limited. A battery case 300 mainly composed of a lightweight metal material having good thermal conductivity is preferable. Examples of such a metal material include aluminum, stainless steel, nickel-plated steel, and the like. The battery case 300 (the case main body 320 and the lid body 340) according to the present embodiment is made of aluminum or an alloy mainly composed of aluminum.

  As shown in FIG. 1, a positive terminal 420 and a negative terminal 440 for external connection are formed on the lid 340. Between the two terminals 420 and 440 of the lid 340, when the internal pressure of the battery case 300 rises to a predetermined level (for example, a set valve opening pressure of about 0.3 to 1.0 MPa), the internal pressure is released. A configured thin safety valve 360 and a liquid injection hole 350 are formed. In FIG. 1, the liquid injection hole 350 is sealed with a sealing material 352 after liquid injection.

  As shown in FIG. 2, the wound electrode body 200 includes a long sheet-like positive electrode (positive electrode sheet 220) and a long sheet-like negative electrode (negative electrode sheet 240) similar to the positive electrode sheet 220 in total of two sheets. Long sheet separators (separators 262 and 264).

  The positive electrode sheet 220 includes a strip-shaped positive electrode current collector 221 and a positive electrode active material layer 223. For the positive electrode current collector 221, for example, a metal foil suitable for the positive electrode can be suitably used. In this embodiment, a strip-shaped aluminum foil having a thickness of about 15 μm is used as the positive electrode current collector 221. An uncoated portion 222 is set along the edge on one side in the width direction of the positive electrode current collector 221. In the illustrated example, the positive electrode active material layer 223 is held on both surfaces of the positive electrode current collector 221 except for the uncoated portion 222 set on the positive electrode current collector 221. The positive electrode active material layer 223 contains a positive electrode active material.

As the positive electrode active material, one type or two or more types of materials conventionally used in lithium ion secondary batteries can be used without any particular limitation. Examples of the positive electrode active material disclosed herein include LiNiCoMnO ₂ (lithium nickel cobalt manganese composite oxide), LiNiO ₂ (lithium nickelate), LiCoO ₂ (lithium cobaltate), LiMn ₂ O ₄ (lithium manganate). And lithium transition metal oxide particles such as LiFePO ₄ (lithium iron phosphate). Here, LiMn ₂ O ₄ has, for example, a spinel structure. LiNiO ₂ or LiCoO ₂ has a layered rock salt structure. LiFePO ₄ has, for example, an olivine structure. Moreover, LiFePO _{4 having} an olivine structure can be further covered with a carbon film.

  The positive electrode active material layer 223 may contain, in addition to the positive electrode active material, one or more materials that can be used as a constituent component of the positive electrode active material layer 223 in a general lithium ion secondary battery as necessary. it can. An example of such a material is a conductive material. Examples of the conductive material include carbon materials such as carbon powder and carbon fiber. One kind selected from such conductive material particles may be used alone, or two or more kinds may be used in combination. As the carbon powder, various carbon blacks (for example, acetylene black, oil furnace black, graphitized carbon black, carbon black, graphite, ketjen black, channel black, furnace black), carbon powder such as graphite powder may be used. it can. Alternatively, conductive metal powder such as nickel powder may be used. In addition, examples of the material that can be used as a component of the positive electrode active material layer include various polymer materials (for example, polyvinylidene fluoride (PVDF)) that can function as a binder for the positive electrode active material.

  The proportion of the positive electrode active material in the entire positive electrode active material layer is suitably about 50% by mass or more (typically 50 to 95% by mass), and usually about 70 to 95% by mass. preferable. When the conductive agent is used, the ratio of the conductive material in the entire positive electrode active material layer can be, for example, about 2 to 20% by mass, and preferably about 2 to 15% by mass. When using a binder, the ratio of the binder to the whole positive electrode active material layer can be, for example, about 1 to 10% by mass, and usually about 2 to 5% by mass is appropriate.

  As a method of forming the positive electrode active material layer 223, a positive electrode active material (typically granular) and other positive electrode active material layer forming components are used in an appropriate solvent (for example, a nonaqueous solvent such as N-methylpyrrolidone (NMP)). A method in which the paste-like composition for forming a positive electrode active material layer dispersed in is applied in a strip shape on one side or both sides (here, both sides) of the positive electrode current collector 221 and dried can be preferably employed. After drying the composition for forming a positive electrode active material layer, an appropriate rolling process (for example, various conventionally known press methods such as a roll press method and a flat plate press method can be employed) is performed, thereby producing a positive electrode active material. The thickness and density of the layer 223 can be adjusted.

  As shown in FIG. 2, the negative electrode sheet 240 includes a strip-shaped negative electrode current collector 241 and a negative electrode active material layer 243. For the negative electrode current collector 241, for example, a metal foil suitable for the negative electrode can be suitably used. In this embodiment, a strip-shaped copper foil having a thickness of about 10 μm is used for the negative electrode current collector 241. On one side in the width direction of the negative electrode current collector 241, an uncoated part 242 is set along the edge. The negative electrode active material layer 243 is held on both surfaces of the negative electrode current collector 241 except for the uncoated portion 242 set on the negative electrode current collector 241. The negative electrode active material layer 243 contains a negative electrode active material.

  A graphite material is used as the negative electrode active material. Examples of the graphite material include graphite (graphite), non-graphitizable carbon (hard carbon), graphitizable carbon (soft carbon), natural graphite, and a material obtained by applying amorphous carbon coating on the surface of natural graphite. Is included. In particular, application to a negative electrode active material (typically, a negative electrode active material substantially composed of natural graphite or artificial graphite) having natural graphite or artificial graphite as a main component is preferable. Such graphite can be flat scaly graphite. Alternatively, spheroidized graphite obtained by spheroidizing the flaky graphite may be used.

  The negative electrode active material layer 243 may contain, in addition to the negative electrode active material, one or more materials that can be used as a constituent component of the negative electrode active material layer 243 in a general lithium ion secondary battery as necessary. it can. Examples of such materials are polymer materials that can function as a binder for the negative electrode active material (for example, styrene-butadiene rubber (SBR)), and function as a thickener for the composition for forming the negative electrode active material layer. Examples thereof include a polymer material to be obtained (for example, carboxymethyl cellulose (CMC)).

  Although not particularly limited, the ratio of the negative electrode active material (graphite) to the entire negative electrode active material layer 243 can be approximately 80% by mass or more (for example, 80 to 99% by mass), and approximately 90% by mass or more ( For example, it is preferable that it is 90-99 mass%, More preferably, it is 95-99 mass%. In the composition using the binder, the proportion of the binder in the entire negative electrode active material layer 243 can be, for example, approximately 0.5 to 10% by mass, and is preferably approximately 1 to 5% by mass.

  As shown in FIG. 2, the separators 262 and 264 are members that separate the positive electrode sheet 220 and the negative electrode sheet 240. In this example, the separators 262 and 264 are made of a strip-shaped sheet material having a predetermined width and having a plurality of minute holes. As the separators 262 and 264, for example, a single layer structure separator or a multilayer structure separator made of a porous polyolefin resin can be used. In this example, as shown in FIG. 2, the width b1 of the negative electrode active material layer 243 is slightly wider than the width a1 of the positive electrode active material layer 223. Furthermore, the widths c1 and c2 of the separators 262 and 264 are slightly wider than the width b1 of the negative electrode active material layer 243 (c1, c2> b1> a1).

  In this embodiment, the wound electrode body 200 is flatly bent in one direction orthogonal to the winding axis WL, as shown in FIG. In the example shown in FIG. 2, the uncoated portion 222 of the positive electrode current collector 221 and the uncoated portion 242 of the negative electrode current collector 241 are spirally exposed on both sides of the separators 262 and 264, respectively. In this embodiment, as shown in FIG. 1, the middle part of the uncoated part 222 (242) is gathered and collected by the electrode terminals 420 and 440 (internal terminals) arranged inside the battery case 300. Welded to tabs 420a, 440a.

  The lithium ion secondary battery 100 having such a configuration is provided in the lid 340 after the electrode body 200 is accommodated inside the opening of the case 300 and the lid 340 is attached to the opening of the case 300, for example. The electrolytic solution 90 is injected from the injection hole 350. The electrolytic solution 90 enters the wound electrode body 200 from the axial direction of the wound shaft WL. Next, the lithium ion secondary battery 100 can be constructed by closing the liquid injection hole 350.

  As described above, the lithium ion secondary battery according to the present invention has better effects of moisture content in the battery and addition of the P-oxalato compound, and can achieve both low SOC output and low resistance at a high level. It can be suitably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. Such secondary batteries may be used in the form of an assembled battery formed by connecting a plurality of them in series and / or in parallel. Accordingly, the present invention provides such a lithium ion secondary battery (which may be in the form of an assembled battery) as a vehicle (typically an automobile, in particular a hybrid automobile (HV), a plug-in hybrid automobile (PHV), an electric automobile (EV). ) Can be suitably used as a driving power source mounted on an automobile equipped with an electric motor such as).

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples.

<< Test Example 1 >>
LiNi _1/3 Co _1/3 Mn _1/3 O ₂ as the positive electrode active material, acetylene black (AB) as the conductive material, and PVDF as the binder have a mass ratio of 90: A composition for forming a positive electrode active material layer was prepared by mixing in NMP so as to be 8: 2. This composition was applied to both sides of a 15 μm thick aluminum foil (positive electrode current collector) and dried to obtain a positive electrode sheet having a positive electrode active material layer formed on both sides of the positive electrode current collector.

  A negative electrode active material obtained by mixing graphite powder as a negative electrode active material, SBR as a binder, and CMC as a thickener in water so that the mass ratio of these materials is 98: 1: 1. A layer forming composition was prepared. This composition was applied to both sides of a 10 μm thick copper foil (negative electrode current collector) and dried to obtain a negative electrode sheet having a negative electrode active material layer formed on both sides of the negative electrode current collector.

The non-aqueous electrolyte is used as a supporting salt in a mixed solvent containing ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of EC: DMC: EMC = 30: 40: 30. LiPF ₆ dissolved at a concentration of 1.1 mol / L was used. Further, lithium difluorobis (oxalato) phosphate (hereinafter referred to as LPFO) as a P-oxalato compound was added to the non-aqueous electrolyte. Here, the LPFO concentration was 0.02 mol / L.

  As the separator, two long porous polyethylene sheets having a thickness of 20 μm were prepared.

<Moisture content in the battery>
The positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte were constructed in an environment showing various different dew points, that is, in an environment with different humidity. And the moisture content was quantified about said positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. As the moisture meter, a Karl Fischer moisture meter was used. From these quantitative values, the total amount of moisture mixed into the battery (that is, the total amount of moisture of each member used for manufacturing the battery) was calculated. As described above, in this evaluation test, a total of 13 types of samples with different total amounts (mg) of water were prepared.

  The positive electrode sheet and the negative electrode sheet were wound through two separators, and the wound body was crushed from the side surface to produce a flat wound electrode body. The wound electrode body thus obtained was housed in a metal box-type battery case together with the non-aqueous electrolyte, and the opening of the battery case was hermetically sealed. In this way, a lithium ion secondary battery for evaluation test was assembled.

<< Test Example 2 >>
For comparison, a lithium ion secondary battery was constructed using a non-aqueous electrolyte not added with LPFO. The conditions were the same as in Test Example 1 except that LPFO was not added.

<Battery capacity (initial capacity)>
The initial charge / discharge treatment was performed on the lithium ion secondary batteries constructed in the above examples. Specifically, in an environment of 25 ° C., the battery is charged with a constant current of 1/3 C (CC charge) until the voltage between the positive and negative terminals becomes 4.1 V, and then the total charging time is 1 Charge at a constant voltage (CV charge) until 5 hours, then rest for 10 minutes, discharge at a constant current of 1/3 C (CC discharge) until the voltage between the positive and negative terminals reaches 3.0 V, then Then, after discharging at a constant voltage (CV discharge) until the total charging time became 1.5 hours, an operation of resting for 10 minutes was defined as 1 cycle, and this was repeated 3 cycles. The CCCV discharge capacity at the third cycle was defined as the battery capacity (initial capacity). In this test lithium ion secondary battery, the battery capacity was about (4.0 Ah. Further, by dividing the addition amount (mg) of the LPFO by the battery capacity (Ah), the LPFO per battery capacity was reduced. In addition, the total amount of water contained in the battery per battery capacity W1 (mg) was calculated by dividing the total amount of water (mg) by the battery capacity (Ah). / Ah) was calculated.

<IV resistance when SOC is 25% charged>
In order to evaluate the output characteristics of each test lithium ion secondary battery in a state of charge of SOC 25%, IV resistance was measured here. The IV resistance was calculated by the following procedure. Procedure 1: It was set as the charge state of SOC25%.
Procedure 2: After Procedure 1, in a 25 ° C. environment, charge is performed for 10 seconds at 1C, 3C, and 5C, respectively.
Here, the measured current value measured in the procedure 2 is plotted on the horizontal axis, and the voltage drop value ΔV, which is a value obtained by subtracting the voltage value at the time of 10 seconds from the initial voltage value in the procedure 2, is plotted on the vertical axis. The IV resistance was determined from the slope. The results are shown in Table 1, Table 2, FIG. 3 and FIG. Table 1 and FIG. 3 show the results of Test Example 1 (LPFO addition amount: 40.5 mg / Ah). Table 2 and FIG. 4 show the results of Comparative Example 1 (without addition of LPFO).

<Resistance increase speed>
The resistance increase rate was measured as follows. After producing the battery, the SOC was adjusted to 60% under the condition of −10 ° C. The battery was stored for 5 hours and adjusted so that the battery reached -10 ° C to the inside. Then, IV resistance was computed from the voltage drop value when discharging at 40 A for 10 seconds. The battery was adjusted to SOC 80% and stored at 60 ° C. The IV resistance was measured at −10 ° C. every 30 days, 60 days, and 90 days at 60 ° C., the square root of the storage period was plotted on the horizontal axis, and the IV resistance was plotted on the vertical axis. The increase rate (dmΩ / d√t) was determined. The results are shown in Table 1, Table 2, FIG. 3 and FIG.

  As shown in Table 1, Table 2, FIG. 3 and FIG. 4, the IV resistance tended to decrease as the moisture content W1 in the battery increased regardless of whether or not LPFO was added. In the case of the battery used here, a low IV resistance of 2.3 mΩ or less could be achieved by setting the water content W1 in the battery to 4.15 mg / Ah or more. Furthermore, by setting the water content W1 in the battery to 8 mg / Ah or more, an extremely low IV resistance of 1.5 mΩ or less could be achieved. From this result, it was confirmed that the output characteristics in the low SOC region are improved by increasing the moisture content W1 in the battery. On the other hand, when the moisture content W1 in the battery increased, the resistance increasing rate also showed an increasing tendency. However, when the water content W1 in the battery is the same, the increase in the resistance increase rate in Test Example 1 in which LPFO was added to the non-aqueous electrolyte was suppressed as compared with Test Example 2. For example, when the moisture content W1 in the battery was 18.37 mg / Ah, the resistance increase rate of Test Example 1 was 0.023, and the resistance increase rate was smaller than that of Test Example 2. Thus, when the moisture content W1 in the battery was the same, there was a tendency that the resistance increasing rate was reduced by adding LPFO to the non-aqueous electrolyte. From this result, it was confirmed that by adding LPFO to the non-aqueous electrolyte, the resistance increase rate is reduced and the increase in resistance can be appropriately suppressed even if the moisture content W1 in the battery is increased.

<< Test Example 3 >>
A lithium ion secondary battery was produced under the same conditions as in Test Example 1 except that the amount of LPFO added was changed to 20.2 mg / Ah. Then, the IV resistance and the resistance increase rate in a state of charge of SOC 25% were evaluated. The results are shown in Table 3.

<< Test Example 4 >>
A lithium ion secondary battery was produced under the same conditions as in Test Example 1 except that the amount of LPFO added was changed to 60.7 mg / Ah. Then, the IV resistance and the resistance increase rate in a state of charge of SOC 25% were evaluated. The results are shown in Table 4.

<< Test Example 5 >>
A lithium ion secondary battery was produced under the same conditions as in Test Example 1 except that the amount of LPFO added was changed to 81 mg / Ah. Then, the IV resistance and the resistance increase rate in a state of charge of SOC 25% were evaluated. The results are shown in Table 5.

  Regarding Test Examples 1 and 3 to 5, the relationship between the ratio of the water content W1 in the battery to the LPFO content W2 (W2 / W1), the IV resistance, and the resistance increase rate is shown in FIG. 5 (Test Example 3) and FIG. Example 1), FIG. 7 (Test Example 4) and FIG. 8 (Test Example 5) are shown respectively.

  As shown in FIGS. 5 to 8, in any of Test Examples 1 and 3 to 5, the resistance increasing rate tends to decrease as the ratio value (W2 / W1) of the moisture content W1 in the battery to the LPFO amount W2 increases. Became. It is presumed that the larger the value of the ratio (W2 / W1), the more likely the reaction between moisture-derived HF and LPFO occurs, and that the increase in resistance of the positive electrode due to HF is suppressed. In the case of the battery used here, by setting the value of the ratio (W2 / W1) to 2.25 or more, a very low resistance increase rate of 0.3 or less could be achieved. From the viewpoint of reducing the resistance increase rate, the value of the ratio (W2 / W1) is suitably 2.25 or more, preferably 3 or more. Thereby, high output can be stably exhibited even in a low SOC region while maintaining good battery performance (typically low resistance).

<< Test Example 6 >>
A lithium ion secondary battery was fabricated under the same conditions as in Test Example 1 except that the moisture content W1 and LPFO amount W2 in the battery were changed as shown in Table 6.

<-30 ° C reaction resistance>
After adjusting the obtained lithium ion secondary battery to SOC 40%, it was put into a thermostat, cooled to −30 ° C., and AC impedance measurement was performed. And the diameter of the semicircle was read from the Nyquist plot of the obtained impedance, and it was set as the reaction resistance (Ω). The AC impedance measurement conditions were an AC applied voltage of 5 mV and a frequency range of 0.001 Hz to 100,000 Hz. The results are shown in Table 6 and FIG. FIG. 9 is a graph showing the relationship between the amount of LPFO and the −30 ° C. reaction resistance.

  As shown in Table 6 and FIG. 9, the reaction resistance tended to increase when the LPFO amount W2 exceeded 405 mg / Ah, regardless of the moisture content W1 in the battery. From the viewpoint of reducing the reaction resistance, the LPFO amount W2 is suitably 405 mg / Ah or less, preferably 300 mg / Ah or less. Thereby, quick charge and high output are exhibited even at low temperatures, and high battery performance is realized.

<< Test Example 7 >>
A lithium ion secondary battery was fabricated under the same conditions as in Test Example 1 except that the LPFO amount W2 was changed to 81 mg / Ah.

<High temperature storage characteristics>
The lithium ion secondary battery obtained above was adjusted to SOC 80%, and then housed in a constant temperature bath at 60 ° C. and subjected to high temperature aging for 30 days. Then, the battery capacity after high temperature storage is measured under the same conditions as the above <battery capacity (initial capacity)>, and [(battery capacity after high temperature storage) / (initial capacity)] × 100 (%) The post capacity retention rate was determined. The results are shown in Table 7 and FIG. FIG. 10 is a graph showing the relationship between the value (W2 / W1) of the ratio of the moisture content in the battery W1 and the LPFO amount W2 and the capacity retention rate after high-temperature storage.

  As shown in Table 7 and FIG. 10, when the value (W2 / W1) of the battery water content W1 and the LPFO content W2 was less than 3, the capacity retention rate after high-temperature storage tended to decrease. From the viewpoint of improving the capacity retention rate after high-temperature storage, the value of the ratio is suitably 3 or more, preferably 5 or more. Thereby, high battery performance is realized without battery capacity decreasing at high temperatures.

  Although the various secondary batteries proposed here have been described above, the present invention is not limited to any of the above-described embodiments unless otherwise specified.

  For example, the battery is not limited to a rectangular battery, and other battery forms may be a cylindrical battery or a laminate battery. Here, the cylindrical battery is a battery in which a wound electrode body is accommodated in a cylindrical battery case. A laminate type battery is a battery in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween. Furthermore, although the electrode body of the secondary battery has been illustrated as a wound electrode body, it may be constituted by a so-called stacked electrode body in which positive electrode sheets and negative electrode sheets are alternately stacked via separators.

  In addition, here, lithium ion secondary batteries have been illustrated, but the secondary batteries proposed here are also employed in non-aqueous electrolyte secondary batteries other than lithium ion secondary batteries unless specifically limited. Yes.

90 non-aqueous electrolyte 100 lithium ion secondary battery 200 wound electrode body 220 positive electrode sheet 221 positive electrode current collector 223 positive electrode active material layer 240 negative electrode sheet 241 negative electrode current collector 243 negative electrode active material layer 262, 264 separator 300 battery case 320 Case body 340 Lid 420 Positive terminal 440 Negative terminal

Claims (8)

A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte,
The non-aqueous electrolyte contains a supporting salt containing fluorine as a constituent element at a concentration of 0.1 mol / L to 5 mol / L,
The non-aqueous electrolyte has the following general formula (I):
A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ (I)
(In the formula (I), A ⁺ is a lithium cation, X is a fluorine atom, and n is 2. )
Including a compound represented by
Here, when the total amount of moisture contained in the battery is W1 and the amount of the compound in the non-aqueous electrolyte solution is W2 before the first charge / discharge treatment, per capacity 1 Ah of the battery, (1) to (3);
(1) 4.15 (mg / Ah) ≦ W1
(2) 20 (mg / Ah) ≦ W2
(3) 2.25 ≦ W2 / W1
A non-aqueous electrolyte secondary battery in which the above relationship is established.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the total amount W1 of the water satisfies 7.14 (mg / Ah) ≦ W1.   The nonaqueous electrolyte secondary battery according to claim 1 or 2, wherein the amount W2 of the compound satisfies W2 ≤ 500 (mg / Ah).   The non-aqueous electrolyte secondary battery according to claim 1, wherein the W2 / W1 satisfies 3 ≦ W2 / W1. A method for producing a non-aqueous electrolyte secondary battery comprising an electrode body comprising a positive electrode, a negative electrode and a separator, and a non-aqueous electrolyte solution:
Preparing the electrode body and the non-aqueous electrolyte, wherein the non-aqueous electrolyte contains a supporting salt containing fluorine as a constituent element at a concentration of 0.1 mol / L to 5 mol / L, The non-aqueous electrolyte has the following general formula (I)
A ⁺ [PX _6-2n (C ₂ O ₄ ) _n ] ⁻ (I)
(In the formula (I), A ⁺ is a lithium cation, X is a fluorine atom, and n is 2 ).
The step of accommodating the prepared electrode body and the non-aqueous electrolyte in a battery case, wherein the total amount of moisture contained in the electrode body and the non-aqueous electrolyte is W1, and the non-aqueous electrolyte is in the non-aqueous electrolyte. When the amount of the compound is W2, the following (1) to (3):
(1) 4.15 mg / Ah ≦ W1
(2) 20 mg / Ah ≦ W2
(3) 2.25 ≦ W2 / W1
And the first charge / discharge process for the electrode body housed in the battery case;
A method for producing a non-aqueous electrolyte secondary battery.   The non-aqueous electrolyte secondary battery manufacturing method according to claim 5, wherein the total amount W1 of the water satisfies 7.14 (mg / Ah) ≦ W1.   The method for producing a non-aqueous electrolyte secondary battery according to claim 5, wherein the amount W2 of the compound satisfies W2 ≦ 500 (mg / Ah). The non-aqueous electrolyte secondary battery manufacturing method according to claim 5, wherein the W2 / W1 satisfies 3 ≦ W2 / W1.

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