JP2014123526A - Nonaqueous electrolyte secondary battery and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery in which a predetermined shape of a battery case can be maintained by suppressing internal pressure rise thereof, and a coat of a mode preferable for the surface of a negative electrode active material is included.SOLUTION: A nonaqueous electrolyte secondary battery 10 includes a positive electrode 64 having a positive electrode active material, a negative electrode 84 having a negative electrode active material, a separator 90 interposed between the positive electrode and negative electrode, and a nonaqueous electrolyte. A coat containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material, and a copper chloride (I)-pyridine complex is carried, as gas adsorbent, on the separator.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery and a method for manufacturing the same.

  Lithium ion secondary batteries and other non-aqueous electrolyte secondary batteries are becoming increasingly important as on-vehicle power supplies or personal computers and portable terminals. In particular, a lithium ion secondary battery that is lightweight and obtains a high energy density is preferable as a high-output power source mounted on a vehicle.

  By the way, in a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, a part of the non-aqueous electrolyte is decomposed during charging, and the decomposition product is formed on the surface of the negative electrode active material (for example, natural graphite particles). A film, that is, a SEI (Solid Electrolyte Interface) film may be formed. The SEI film plays a role of protecting the negative electrode active material, but is formed by consuming charge carriers (for example, lithium ions) in the non-aqueous electrolyte. In other words, the charge carriers can no longer contribute to the battery capacity by being fixed in the SEI film. For this reason, if the amount of the SEI film is large, it becomes a factor of reducing the capacity retention rate (decreasing cycle characteristics).

  In order to cope with such a problem, various additives are added to the non-aqueous electrolyte in order to form a stable film on the surface of the negative electrode active material in advance instead of the SEI film. For example, Patent Document 1 describes a non-aqueous electrolyte solution for a secondary battery containing a compound having an oxalato complex as an anion (hereinafter referred to as “oxalato complex compound”).

JP 2005-255952 A JP 2008-159576 A JP 2012-59489 A

By the way, in the non-aqueous electrolyte secondary battery containing an oxalato complex compound as an additive, a stable film is formed on the surface of the negative electrode active material by decomposing the oxalato complex compound during initial charge / discharge. The higher the concentration of the oxalato complex compound contained in the non-aqueous electrolyte solution, the more likely the film of the preferred embodiment is formed on the surface of the negative electrode active material, but the formation of the film is based on the reductive decomposition of the oxalato complex compound. Carbon monoxide (CO) and carbon dioxide (CO ₂ ) are mainly generated. For this reason, the higher the concentration of the oxalato complex compound contained in the non-aqueous electrolyte, the more CO and CO ₂ are present in the battery case based on the reductive decomposition of the oxalato complex compound, and the internal pressure of the battery case increases. Can do. If the internal pressure of the battery case becomes too large, the volume in the non-aqueous electrolyte secondary battery increases and the battery case may expand in the thickness direction. Thus, if the battery case expands in the thickness direction, it becomes difficult to constrain a plurality of nonaqueous electrolyte secondary batteries (unit cells) to construct a battery pack having a predetermined shape.

  The present invention has been created to solve the above-described conventional problems, and its purpose is to maintain a predetermined shape (that is, a predetermined thickness) of the battery case by suppressing an increase in the internal pressure of the battery case. In addition, another object is to provide a non-aqueous electrolyte secondary battery including a coating of a preferred embodiment on the surface of the negative electrode active material and a method for manufacturing the same.

  In order to achieve the above object, the present invention provides a non-aqueous electrolyte secondary battery. That is, the non-aqueous electrolyte secondary battery disclosed herein includes a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, and non-aqueous electrolysis. And a battery case containing the electrode body and the non-aqueous electrolyte. A film containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material, and the separator carries a copper (I) chloride-pyridine complex as a gas adsorbent.

In this specification, the “non-aqueous electrolyte secondary battery” includes a non-aqueous electrolyte (typically, an electrolyte containing a supporting salt (supporting electrolyte) in a non-aqueous solvent (organic solvent)). Battery.
In the present specification, the term “secondary battery” refers to a battery that can be repeatedly charged and discharged, and is a term that includes a so-called chemical battery such as a lithium ion secondary battery and a physical battery such as an electric double layer capacitor.

In the non-aqueous electrolyte secondary battery provided by the present invention, a film containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material, and copper chloride (I) is used as a gas adsorbent on the separator. ) -Pyridine complex is supported.
According to such a configuration, the gas (typically CO and CO ₂ ) generated when a coating film containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material is made of copper chloride (I ) -Pyridine complex absorbs (adsorbs), and thus the increase in the internal pressure of the battery case is suppressed. For this reason, deformation of the shape of the battery case (particularly the shape in the thickness direction) accompanying the generation of gas is prevented, and the non-aqueous electrolyte can stably build the assembled battery with a preset binding force It can be a secondary battery. In addition, since a film containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material in a preferable embodiment, such a nonaqueous electrolyte secondary battery exhibits excellent battery characteristics.
Patent Document 2 describes a lithium ion secondary battery in which a positive electrode contains a gel polymer that traps a gas generated from a positive electrode active material, but has a configuration different from that of the present invention described above. Patent Document 3 describes a laminated battery (lithium ion battery) in which a gas adsorbent is arranged on the inner surface of a corner portion of a storage unit that accommodates an electrode group. The configuration is different from that of the present invention described above.

In a preferred embodiment of the non-aqueous electrolyte secondary battery disclosed herein, the supported amount of the copper (I) chloride-pyridine complex is 1 mmol or more per 1 g of the separator.
According to such a configuration, the gas (typically CO and CO ₂ ) generated when the coating film is formed on the surface of the negative electrode active material is more effectively absorbed by the copper (I) chloride-pyridine complex ( Therefore, the increase in the internal pressure of the battery case is suppressed. For this reason, the deformation | transformation of the shape (especially shape of thickness direction) of the battery case accompanying generation | occurrence | production of gas is prevented effectively, and the nonaqueous electrolyte secondary battery maintains the high battery performance.

In another preferred embodiment of the nonaqueous electrolyte secondary battery disclosed herein, the nonaqueous electrolyte includes an oxalato complex compound containing at least one of phosphorus and boron as a constituent element, a nonaqueous solvent, including. Preferably, the oxalato complex compound is LiPF ₂ (C ₂ O ₄ ) ₂ .
According to such a configuration, a coating can be further formed on the surface of the negative electrode active material during charge / discharge of the non-aqueous electrolyte secondary battery.

In another preferred embodiment of the non-aqueous electrolyte secondary battery disclosed herein, the positive electrode active material is a lithium transition metal composite oxide, and the negative electrode active material has a graphite structure at least partially. It is a carbon material.
According to such a configuration, it is possible to obtain a non-aqueous electrolyte secondary battery with more excellent output performance.

  According to the present invention, as another aspect for realizing the above object, a non-aqueous electrolyte secondary comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. A method of manufacturing a battery is provided. That is, the non-aqueous electrolyte secondary battery manufacturing method disclosed herein includes preparing a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material, and using a copper (I) chloride-pyridine complex as a gas adsorbent. A copper chloride (I) -pyridine complex is supported between the prepared positive electrode and the prepared negative electrode by immersing the separator in a solution containing the copper chloride (I) -pyridine complex on the separator; Producing an electrode body by interposing a separator on which is supported, producing an assembly in which the electrode body is housed in a battery case, and an oxalato complex compound containing at least one of phosphorus and boron as a constituent element; Injecting a non-aqueous electrolyte containing a non-aqueous solvent into the battery case, charging the assembly to a predetermined charging voltage, and then charging to a predetermined discharging voltage. Encompasses carrying out the discharge, the.

According to such a manufacturing method, by performing a predetermined charge / discharge treatment on the assembly, the oxalato complex compound containing at least one of phosphorus and boron contained in the non-aqueous electrolyte as a constituent element is decomposed, A film based on the oxalato complex compound is formed on the surface of the negative electrode active material. Further, CO and CO ₂ are mainly generated based on the decomposition of the oxalato complex compound, and CO and CO ₂ are filled in the battery case. However, the separator of the electrode body has copper (I) chloride as a gas adsorbent. Since the pyridine complex is supported, CO and CO ₂ are absorbed (adsorbed) by the copper (I) chloride-pyridine complex. Thereby, the raise of the internal pressure of a battery case can be suppressed. For this reason, deformation of the shape of the battery case (especially the shape in the thickness direction) accompanying the generation of gas is prevented, and the non-aqueous electrolyte secondary that can stably build the assembled battery with a preset binding force A battery can be manufactured. Moreover, according to this manufacturing method, the process of extracting separately the gas based on decomposition | disassembly of an oxalato complex compound from a battery case becomes unnecessary.

In a preferred embodiment of the production method disclosed herein, the copper (I) chloride-pyridine complex supported on the separator is contained in the solution so that the supported amount is 1 mmol or more per 1 g of the separator. The addition amount of the copper (I) chloride-pyridine complex is adjusted.
According to such a configuration, the gas (typically CO and CO ₂ ) generated when the coating film is formed on the surface of the negative electrode active material is more effectively absorbed by the copper (I) chloride-pyridine complex ( Therefore, an increase in the internal pressure of the battery case is suppressed. For this reason, a non-aqueous electrolyte secondary battery in which deformation of the shape of the battery case (particularly the shape in the thickness direction) accompanying the generation of gas is prevented can be produced.

In another preferred embodiment of the production method disclosed herein, LiPF ₂ (C ₂ O ₄ ) ₂ is used as the oxalato complex compound.
According to such a configuration, it is possible to form a film of a preferred embodiment on the surface of the negative electrode active material. Preferably, the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte is 0.02 mol / L to 0.04 mol / L. According to this configuration, it is possible to produce a nonaqueous electrolyte secondary battery with reduced reaction resistance and an excellent capacity retention rate.

In another preferred embodiment of the production method disclosed herein, a lithium transition metal composite oxide is used as the positive electrode active material, and a carbon material having a graphite structure at least partially is used as the negative electrode active material.
According to this configuration, a non-aqueous electrolyte secondary battery with better output performance can be produced.

  As described above, any non-aqueous electrolyte secondary battery disclosed herein or a non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) obtained by any of the manufacturing methods disclosed herein. Then, since the surface of the negative electrode active material is provided with a coating of a preferable embodiment, the battery performance is excellent, and the non-aqueous solution in which a predetermined shape of the battery case is maintained is suppressed by suppressing an increase in the internal pressure of the battery case. It can be an electrolyte secondary battery. Therefore, a plurality of (for example, 40 to 80) non-aqueous electrolyte secondary batteries obtained by any of the non-aqueous electrolyte secondary batteries disclosed herein or any of the manufacturing methods disclosed herein. ) Are connected by a predetermined binding force (typically connected in series). It can also be used as a drive power source for vehicles (typically automobiles, particularly automobiles equipped with electric motors such as hybrid cars, electric cars, and fuel cell cars).

It is a perspective view which shows typically the external shape of the non-aqueous-electrolyte secondary battery which concerns on one Embodiment of this invention. It is sectional drawing which follows the II-II line | wire in FIG. It is a flowchart for demonstrating the manufacturing method of the nonaqueous electrolyte secondary battery which concerns on one Embodiment of this invention. It is a perspective view which shows typically the assembled battery which combined the nonaqueous electrolyte secondary battery which concerns on one Embodiment of this invention. It is a side view which shows typically the vehicle (automobile) provided with the nonaqueous electrolyte secondary battery which concerns on this invention. It is a graph which shows the relationship between the amount of gas adsorbents, and the amount of gas generation. LiPF _{2 (C 2 O 4)} is a graph showing the relationship between the ₂ concentrations and reaction resistance. LiPF _{2 (C 2 O 4)} is a graph showing the relationship between the _two levels and capacity maintenance ratio.

  Hereinafter, preferred embodiments of the present invention will be described. It should be noted that matters other than matters specifically mentioned in the present specification and necessary for carrying out 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. 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.

  As a preferred embodiment of a method for producing a non-aqueous electrolyte secondary battery disclosed herein, a method for producing a lithium ion secondary battery will be described in detail as an example. Is not intended to be limited to such types of secondary batteries. For example, the present invention can also be applied to a non-aqueous electrolyte secondary battery using other metal ions (for example, magnesium ions) as a charge carrier.

  As shown in FIG. 3, the manufacturing method of the lithium ion secondary battery (nonaqueous electrolyte secondary battery) disclosed herein includes a positive and negative electrode preparation step (S10), a gas adsorbent carrying step (S20), An electrode body production process (S30), an assembly production process (S40), an injection process (S50), and a charge / discharge process (S60) are included.

≪Positive electrode preparation process (S10) ≫
First, the positive and negative electrode preparation step (S10) will be described. In the present embodiment, as the positive and negative electrode preparation step, a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material are prepared.

  The negative electrode of the lithium ion secondary battery disclosed herein includes a negative electrode current collector and a negative electrode mixture layer including at least a negative electrode active material formed on the surface of the negative electrode current collector. The negative electrode mixture layer can contain optional components such as a binder and a thickener as needed in addition to the negative electrode active material.

  As the negative electrode current collector, a conductive member made of a metal having good conductivity is preferably used, like the current collector used in the negative electrode of a conventional lithium ion secondary battery. For example, copper, nickel, or an alloy mainly composed of them can be used. The shape of the negative electrode current collector can vary depending on the shape or the like of the lithium ion secondary battery, and is not particularly limited, and may be various forms such as a foil shape, a sheet shape, a rod shape, and a plate shape.

As the negative electrode active material, one kind or two or more kinds of materials conventionally used for lithium ion secondary batteries can be used without particular limitation. For example, a particulate (or spherical, scale-like) carbon material including a graphite structure (layered structure) at least partially, a lithium transition metal composite oxide (for example, a lithium titanium composite oxide such as Li ₄ Ti ₅ O ₁₂ ), Lithium transition metal composite nitride, etc. Examples of the carbon material include natural graphite, artificial graphite (artificial graphite), non-graphitizable carbon (hard carbon), graphitizable carbon (soft carbon), and the like. The average particle diameter of the negative electrode active material is, for example, in the range of about 1 μm to 50 μm (usually 5 μm to 30 μm), which is based on various commercially available laser diffraction / scattering methods. The median diameter (D50: 50% volume average particle diameter) that can be derived from the particle size distribution measured based on the particle size distribution measuring device. For example, a negative electrode active material at least partially coated with an amorphous carbon film can be obtained by mixing a negative electrode active material with a pitch and baking it.

  As said binder, the thing similar to the binder used for the negative electrode of a general lithium ion secondary battery can be employ | adopted suitably. For example, when an aqueous paste composition is used to form the negative electrode mixture layer, a water-soluble polymer material or a water-dispersible polymer material can be preferably used. Examples of the water dispersible polymer include rubbers such as styrene butadiene rubber (SBR); polyethylene oxide (PEO), vinyl acetate copolymer and the like. Styrene butadiene rubber is preferably used.

  The “aqueous paste-like composition” is a concept indicating a composition using water or a mixed solvent mainly composed of water as a dispersion medium for the negative electrode active material. As a solvent other than water constituting such a mixed solvent, one or more organic solvents (lower alcohol, lower ketone, etc.) that can be uniformly mixed with water can be appropriately selected and used.

  As the thickener, for example, a water-soluble or water-dispersible polymer can be adopted. Examples of the water-soluble polymer include cellulose polymers such as carboxymethylcellulose (CMC), methylcellulose (MC), cellulose acetate phthalate (CAP), and hydroxypropylmethylcellulose (HPMC); polyvinyl alcohol (PVA); . In addition, the same materials as those mentioned as the binder can be appropriately employed.

  The negative electrode disclosed here can be suitably manufactured, for example, generally by the following procedure. A paste-like composition for forming a negative electrode mixture layer is prepared by dispersing the above-described negative electrode active material and other optional components (binder, thickener, etc.) in an appropriate solvent (for example, water). . A negative electrode comprising a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector by applying the prepared composition to the negative electrode current collector, drying, and then compressing (pressing) the negative electrode current collector. Can be produced.

The positive electrode of the lithium ion secondary battery disclosed here includes a positive electrode current collector and a positive electrode mixture layer including at least a positive electrode active material formed on the surface of the positive electrode current collector. The positive electrode mixture layer may contain an optional component such as a conductive material and a binder (binder) in addition to the positive electrode active material.

  As the positive electrode current collector, aluminum or an aluminum alloy mainly composed of aluminum is used as in the case of the positive electrode current collector used in the positive electrode of a conventional lithium ion secondary battery. The shape of the positive electrode current collector can be the same as the shape of the negative electrode current collector.

Examples of the positive electrode active material include materials capable of inserting and extracting lithium ions, and include lithium-containing compounds (for example, lithium transition metal composite oxides) containing a lithium element and one or more transition metal elements. For example, lithium nickel composite oxide (for example, LiNiO ₂ ), lithium cobalt composite oxide (for example, LiCoO ₂ ), lithium manganese composite oxide (for example, LiMn ₂ O ₄ ), or lithium nickel cobalt manganese composite oxide (for example, LiNi _{1). / 3} Co _1/3 Mn _1/3 O ₂ ), a ternary lithium-containing composite oxide.
In addition, a polyanionic compound (for example, LiFePO ₄₎ whose general formula is represented by LiMPO _4, LiMVO _4, or Li ₂ MSiO ₄ (wherein M is at least one element of Co, Ni, Mn, and Fe), etc. ₄ , LiMnPO ₄ , LiFeVO ₄ , LiMnVO ₄ , Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ , Li ₂ CoSiO ₄ ) may be used as the positive electrode active material.

  The conductive material is not limited to a specific conductive material as long as it is conventionally used in this type of lithium ion secondary battery. For example, carbon materials such as carbon powder and carbon fiber can be used. As the carbon powder, various carbon blacks (for example, acetylene black, furnace black, ketjen black, etc.), carbon powders such as graphite powder can be used. Among these, acetylene black (AB) is a preferable carbon powder. Such conductive materials can be used singly or in appropriate combination of two or more.

  As said binder (binder), the thing similar to the binder used for the positive electrode of a common lithium ion secondary battery can be employ | adopted suitably. For example, when a solvent-based paste-like composition (a paste-like composition includes a slurry-like composition and an ink-like composition) is used as the composition for forming the positive electrode mixture layer, a polyfluoride is used. Polymer materials that dissolve in an organic solvent (non-aqueous solvent) such as vinylidene chloride (PVDF) and polyvinylidene chloride (PVDC) can be used. Alternatively, when an aqueous paste composition is used, a water-soluble (soluble in water) polymer material or a water-dispersible (water-dispersible) polymer material can be preferably used. For example, polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR) and the like can be mentioned. In addition, the polymer material illustrated above may be used as a thickener or other additives in the above composition in addition to being used as a binder.

  Here, the “solvent-based paste composition” is a concept indicating a composition in which the dispersion medium of the positive electrode active material is mainly an organic solvent (non-aqueous solvent). As the organic solvent, for example, N-methyl-2-pyrrolidone (NMP) can be used.

  The positive electrode disclosed here can be suitably manufactured, for example, generally by the following procedure. A paste-like composition for forming a positive electrode mixture layer is prepared by dispersing, in an organic solvent, the above-described positive electrode active material, conductive material, and a binder that is soluble in an organic solvent. A positive electrode comprising a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector by applying the prepared composition to the positive electrode current collector, drying, and then compressing (pressing) the positive electrode current collector. Can be produced.

≪Gas adsorbent carrying step (S20) ≫
Next, the gas adsorbent carrying step (S20) will be described. In the present embodiment, in the gas adsorbent carrying step, a separator is prepared, and the gas adsorbent carrying separator is produced by carrying the gas adsorbent on the prepared separator.

  The separator disclosed here can use a conventionally well-known thing without a restriction | limiting in particular. For example, a porous sheet made of resin (a microporous resin sheet) can be preferably used. A porous polyolefin resin sheet such as polyethylene (PE) or polypropylene (PP) is preferred. For example, a PE sheet, a PP sheet, a sheet having a three-layer structure (PP / PE / PP structure) in which PP layers are laminated on both sides of the PE layer, and the like can be suitably used.

  The thickness of the separator is preferably, for example, about 10 μm to 30 μm (for example, about 16 μm to 20 μm). If the thickness of the separator is more than 30 μm, the ion conductivity of the separator may be lowered. On the other hand, if the thickness of the separator is too smaller than 10 μm, the separator itself may be damaged (film breakage) during charging and discharging.

  For example, the porosity of the separator is preferably about 40% to 65% (preferably about 45% to 55%). The porosity is expressed by volume% (vol%), but is simply expressed as% below. When the separator has a three-layer structure in which PP layers are laminated on both sides of the PE layer, the porosity of the PP layer is preferably about 35% to 50%. The porosity of the PE layer is preferably about 45% to 65%. If the porosity is too small, the amount of electrolyte solution that can be held in the separator is reduced, and the ionic conductivity may be reduced. On the other hand, when the porosity is too large, the strength of the separator is insufficient, and there is a possibility that film breakage is likely to occur.

  Here, the “porosity” is the ratio (also referred to as porosity) of pores (pores) in the separator. For example, “the porosity of the separator” is a ratio (Vb / Va) between the volume Vb of the void formed inside the separator and the apparent volume Va of the separator. The apparent volume Va of the separator can be obtained, for example, by the product of the area Sn1 in plan view of the separator and the thickness c of the separator (Va = Sn1 × c). The volume Vb of the voids formed inside the separator can be measured by using, for example, a mercury porosimeter. In this measurement method, “hole” means a hole opened to the outside. The closed space in the separator is not included in the “hole” in this way. The mercury porosimeter is a device that measures the pore distribution of a porous body by a mercury intrusion method.

The gas adsorbent disclosed here may be any material that can absorb (adsorb) carbon monoxide (CO) or carbon dioxide (CO ₂ ), and examples thereof include a copper (I) chloride-pyridine complex. The copper (I) chloride-pyridine complex is particularly excellent in performance of absorbing (adsorbing) carbon monoxide (CO) and carbon dioxide (CO ₂ ).
The amount of the gas adsorbent supported on the separator is 0.1 mmol or more per gram of separator, and preferably 1 mmol or more (for example, 1 mmol to 10 mmol).

≪Method of loading gas adsorbent≫
A gas adsorbent-carrying separator in which a gas adsorbent is carried on the separator can be suitably manufactured, for example, as follows. Hereinafter, a preferred embodiment of the production method will be described in detail by taking as an example the case of using a copper (I) chloride-pyridine complex as a gas adsorbent, but the application target of this production method is limited to such a gas adsorbent. Not intended. Although acetonitrile is used as a solvent for dissolving copper (I) chloride and pyridine, it is not limited to acetonitrile, and other organic solvents may be used as long as copper (I) chloride and pyridine can be dissolved.

  One preferred embodiment of the method for producing a gas adsorbent-carrying separator disclosed herein includes mixing copper (I) chloride and acetonitrile to prepare an acetonitrile solution of copper (I) chloride. It comprises mixing an acetonitrile solution of copper (I) chloride prepared above and pyridine to prepare an acetonitrile solution of a copper (I) chloride-pyridine complex. Immersing the separator in an acetonitrile solution of the copper (I) chloride-pyridine complex prepared above. Drying the soaked separator to remove acetonitrile.

  Preparing an acetonitrile solution of the copper chloride (I), preparing an acetonitrile solution of the copper chloride (I) -pyridine complex, and immersing the separator in an acetonitrile solution of the copper chloride (I) -pyridine complex , Under an inert atmosphere (for example, under a nitrogen atmosphere of 1 atm). Moreover, the temperature at this time is 20 to 30 degreeC, for example. The separator soaked is dried under reduced pressure (for example, −0.1 atm to −0.8 atm on the basis of atmospheric pressure). By drying the separator and removing acetonitrile, a gas adsorbent-carrying separator in which the copper (I) chloride-pyridine complex is carried on the separator can be produced. The supported amount of the copper chloride (I) -pyridine complex supported on the separator can be realized by adjusting the addition amount of the copper chloride (I) -pyridine complex contained in the acetonitrile solution. That is, by adjusting the amounts of copper chloride (I) and pyridine added to acetonitrile, the amount of copper chloride (I) -pyridine complex supported on the separator can be adjusted to a desired value.

≪Electrode body manufacturing step (S30) ≫
Next, the electrode body manufacturing step (S30) will be described. In the electrode body manufacturing step, an electrode body is manufactured using the prepared positive electrode, negative electrode, and gas adsorbent-carrying separator.
An electrode body (for example, a stacked electrode body or a wound electrode body) of a lithium ion secondary battery disclosed herein includes a positive electrode, a negative electrode, and a gas adsorbent-carrying separator interposed between the positive electrode and the negative electrode. And. Here, a description will be given by taking as an example a wound-type electrode body (wound electrode body) including the positive electrode formed in a sheet shape, the negative electrode formed in a sheet shape, and the gas adsorbent-carrying separator. It is not intended to be limited to such a form.

FIG. 2 shows a wound electrode body 50 according to the present embodiment. As shown in FIG. 2, the wound electrode body 50 has a sheet-like positive electrode 64 and a sheet-like negative electrode 84 which are laminated in a state where a total of two long gas adsorbent carrying separators 90 are interposed. It is a flat-shaped wound electrode body 50 produced by winding in the direction and then crushing the obtained wound body from the side direction and causing it to be ablated. Note that at least one of the two separators interposed between the positive electrode 64 and the negative electrode 84 may be a gas adsorbent-carrying separator.
At the time of the above lamination, the positive electrode mixture layer non-formed portion of the positive electrode 64 (that is, the portion where the positive electrode current collector 62 is exposed without the formation of the positive electrode mixture layer 66) 63 and the negative electrode mixture layer of the negative electrode 84 are not formed. The positive electrode 64 and the negative electrode 84 are formed so that the formation part (that is, the part where the negative electrode current collector 82 is exposed without forming the negative electrode mixture layer 86) 83 protrudes from both sides in the width direction of the gas adsorbent-carrying separator 90. Are overlapped with a slight shift in the width direction. As a result, in the lateral direction with respect to the winding direction of the wound electrode body 50, the electrode mixture layer non-formed portions 63 and 83 of the positive electrode 64 and the negative electrode 84 are respectively wound core portions (that is, the positive electrode mixture layer 66 and the positive electrode 64). The negative electrode mixture layer 86 of the negative electrode 84 and the two gas adsorbent-carrying separators 90 are protruded outward from the portion where the gas adsorbent-carrying separator 90 is tightly wound. A positive electrode terminal 60 (for example, made of aluminum) is joined to the positive electrode mixture layer non-formed portion 63 to electrically connect the positive electrode 64 and the positive electrode terminal 60 of the wound electrode body 50 formed in the flat shape. Similarly, a negative electrode terminal 80 (for example, made of nickel) is joined to the negative electrode mixture layer non-forming portion 83 to electrically connect the negative electrode 84 and the negative electrode terminal 80. The positive and negative electrode terminals 60 and 80 and the positive and negative electrode current collectors 62 and 82 can be joined by, for example, ultrasonic welding, resistance welding, or the like.

<< Assembly manufacturing process (S40) >>
Next, the assembly manufacturing step (S40) will be described. In the present embodiment, the fabricated electrode body 50 is accommodated in the battery case 15 to produce the assembly 70.

  As shown in FIGS. 1 and 2, the battery case 15 of the present embodiment is a battery case made of metal (for example, made of aluminum, and also preferably made of resin or laminate film), and the upper end is open. A case body (exterior case) 30 having a flat bottomed box shape (typically a rectangular parallelepiped shape) and a lid body 25 that closes the opening 20 of the case body 30 are provided. On the upper surface of the battery case 15 (that is, the lid body 25), a positive electrode terminal 60 that is electrically connected to the positive electrode 64 of the wound electrode body 50 and a negative electrode terminal that is electrically connected to the negative electrode 84 of the wound electrode body 50. 80 is provided. In addition, the lid body 25 is formed with an inlet 45 for injecting a non-aqueous electrolyte described later into the case body 30 (battery case 15) in which the wound electrode body 50 is accommodated. The injection port 45 is sealed with a sealing plug 48 after an injection step (S50) described later. Further, as in the case of the conventional lithium ion secondary battery, the lid 25 is provided with a safety valve 40 for discharging the gas generated inside the battery case 15 to the outside of the battery case 15 when the battery is abnormal. ing. The wound electrode body 50 is placed in a case in a posture in which the wound axis of the wound electrode body 50 is laid down (that is, the opening 20 is formed in the normal direction of the wound axis of the wound electrode body 50). Housed in the main body 30. Thereafter, the opening portion 20 of the case body 30 is sealed with the lid body 25, thereby producing the assembly 70. The lid 25 and the case body 30 are joined by welding or the like.

≪Injection process (S50) ≫
Next, an injection | pouring process (S50) is demonstrated. In the present embodiment, as the injection step, a nonaqueous electrolyte is injected into the battery case. The nonaqueous electrolytic solution used in the injection step (S50) includes an oxalate complex compound (hereinafter referred to as “PB-oxalato compound”) containing at least one of phosphorus and boron as an additive, and a nonaqueous solvent. And at least. Typically, in addition to the PB-oxalato compound and the non-aqueous solvent, a non-aqueous electrolyte solution further containing a lithium compound (supporting salt) that can be dissolved in the non-aqueous solvent and supply lithium ions is used.

The PB-oxalato compound disclosed here is an oxalato complex having a structural portion in which at least one oxalate ion (C ₂ O ₄ ²⁻ ) is coordinated to phosphorus (P) or boron (B). As the PB-oxalato compound, one produced by a known method or one obtained by purchasing a commercially available product is not particularly limited, and one or two or more kinds can be used. As a preferable BP-oxalato compound, a phosphorus-containing oxalato complex compound represented by the following formula (I) is exemplified. Moreover, the boron containing oxalato complex compound represented by following formula (II) is illustrated as a preferable BP-oxalato compound.

Here, A ⁺ in formulas (I) and (II) may be either an inorganic cation or an organic cation. Specific examples of the inorganic cation include alkali metal cations such as Li, Na, and K; alkaline earth metal cations such as Be, Mg, and Ca; other, Ag, Zn, Cu, Co, Fe, Ni, Mn, And metal cations such as Ti, Pb, Cr, V, Ru, Y, lanthanoids and actinoids; protons; and the like. Specific examples of organic cations include tetraalkylammonium ions such as tetrabutylammonium ion, tetraethylammonium ion and tetramethylammonium ion; trialkylammonium ions such as triethylmethylammonium ion and triethylammonium ion; other pyridinium ions and imidazoliums Ion, tetraethylphosphonium ion, tetramethylphosphonium ion, tetraphenylphosphonium ion, triphenylsulfonium ion, triethylsulfonium ion; and the like. Examples of preferred cations include lithium ions, tetraalkylammonium ions and protons.

As the BP-oxalato compound, a compound represented by the formula (I) is preferably used. Of these, LiPF ₂ (C ₂ O ₄ ) ₂ represented by the formula (I) is preferably used. Further, lithium bis (oxalato) borate (LiB (C ₂ O ₄ ) ₂ ) represented by the formula (II) is preferably used.

The addition amount of the BP-oxalato compound (for example, LiPF ₂ (C ₂ O ₄ ) ₂ ) is 0.01 mol / L or more and 0.1 mol / L or less with respect to the nonaqueous electrolytic solution. Preferably, it is 0.02 mol / L or more and 0.06 mol / L or less. More preferably, they are 0.02 mol / L or more and 0.04 mol / L or less. When the addition amount is in the above range, the effect of the present invention can be more exerted, and higher battery performance can be realized.

As the non-aqueous solvent (organic solvent), aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones, and lactones can be used. For example, carbonates such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) are exemplified. Such organic solvents can be used alone or in combination of two or more.
Examples of the supporting salt (lithium compound) include lithium salts such as LiPF ₆ , LiClO ₄ , LiAsF ₆ , Li (CF ₃ SO ₂ ) ₂ N, LiBF ₄ , and LiCF ₃ SO ₃ . These supporting salts can be used alone or in combination of two or more. LiPF ₆ is particularly preferable. The concentration of the supporting salt is not particularly limited, but if it is too low, the amount of charge carriers (typically lithium ions) contained in the non-aqueous electrolyte is insufficient, and the ionic conductivity tends to decrease. On the other hand, when the concentration is extremely high, the viscosity of the non-aqueous electrolyte increases in a temperature range below room temperature (for example, 0 ° C. to 30 ° C.), and ion conductivity tends to decrease. For this reason, the concentration of the supporting salt is, for example, 0.1 mol / L or more (for example, 0.8 mol / L or more) and preferably 2 mol / L or less (for example, 1.5 mol / L or less).

≪Charging / discharging process (S60) ≫
Next, the charge / discharge step (S60) will be described. In the present embodiment, the PB-oxalato compound-derived film is formed on the surface of the negative electrode active material in the negative electrode mixture layer 86 by charging the assembly 70 to a predetermined charging voltage.

In this step, for example, the assembly 70 is charged at a charging rate of about 0.1 C to 2 C up to an upper limit voltage (e.g., 3.7 V to 4.1 V) when the battery is used. During the initial charging, the PB-oxalato compound is decomposed, and a film derived from the PB-oxalato compound is formed on the surface of the negative electrode active material in the negative electrode mixture layer 86. Gases (typically CO and CO ₂ ) generated when the PB-oxalato compound is decomposed are absorbed (adsorbed) by the copper (I) chloride-pyridine complex supported on the separator. For this reason, the increase in the internal pressure of the battery case is suppressed by the gas based on the reductive decomposition of the PB-oxalato compound, and the deformation of the shape of the battery case 15 (particularly the shape in the thickness direction) accompanying the generation of gas is prevented. Therefore, it is not necessary to remove the gas generated in the battery case 15 after the charge / discharge process. After charging the assembly 70, the battery is discharged to a predetermined voltage (for example, 3V to 3.2V) at a discharge rate of about 0.1C to 2C. Moreover, it is preferable to repeat the said charging / discharging several times (for example, 3 times). By performing the charging / discharging process on the assembly 70 in this manner, the assembly 70 becomes a usable battery, that is, a lithium ion secondary battery (non-aqueous electrolyte secondary battery) 10 (FIGS. 1 and 2). reference). “1C” means the amount of current that can charge the battery capacity (Ah) predicted from the theoretical capacity of the positive electrode in one hour.

  Next, the lithium ion secondary battery (nonaqueous electrolyte secondary battery) 10 manufactured by the manufacturing method disclosed herein will be described.

  As shown in FIG. 2, the lithium ion secondary battery 10 according to the present embodiment is a laminated or wound electrode body (here, a wound electrode body) including a positive electrode 64 and a negative electrode 84 and a gas adsorbent-carrying separator 90. 50, a non-aqueous electrolyte, and a battery case 15 that houses the electrode body 50 and the non-aqueous electrolyte. In the non-aqueous electrolyte, the PB-oxalato compound that has not been decomposed in the charge / discharge step may remain. The positive electrode 64 includes a positive electrode current collector 62 and a positive electrode mixture layer 66 including at least a positive electrode active material formed on the surface of the positive electrode current collector 62. The negative electrode 84 includes a negative electrode current collector 82 and a negative electrode mixture layer 86 including at least a negative electrode active material formed on the surface of the negative electrode current collector 82. The gas adsorbent-carrying separator 90 carries a copper (I) chloride-pyridine complex as a gas adsorbent. The supported amount of copper chloride (I) -pyridine complex is 0.1 mmol or more (preferably 1 mmol or more, for example, 1 mmol to 10 mmol) per 1 g of the separator.

In the lithium ion secondary battery 10 according to the present embodiment, in the charge / discharge step S60, a gas (typically, generated when a film based on the reductive decomposition of the PB-oxalato compound is formed on the surface of the negative electrode active material (typically CO and CO ₂ ) are absorbed (adsorbed) by the copper (I) chloride-pyridine complex supported on the gas adsorbent-supporting separator 90. For this reason, an increase in the internal pressure of the battery case 15 is suppressed. Thereby, the deformation | transformation of the shape (especially shape of thickness direction) of the battery case 15 accompanying generation | occurrence | production of gas is prevented. Moreover, since the film containing at least one of phosphorus and boron is formed in a preferable mode on the surface of the negative electrode active material, the lithium ion secondary battery 10 exhibits excellent battery characteristics. The amount of phosphorus (P) or boron (B) contained in the coating can be grasped by analyzing the coating by ICP (high frequency inductively coupled plasma) emission analysis, ion chromatography or the like.

Next, an example of an assembled battery (typically an assembled battery in which a plurality of single cells are connected in series) 200 including the lithium ion secondary battery 10 as a single battery and a plurality of the single batteries will be described. . In the unit cell 10 according to the present embodiment, since the deformation of the battery case 15 (particularly the shape in the thickness direction) due to the generation of gas is prevented, the assembled battery 200 is stabilized with a preset binding force. Can be built.
As shown in FIG. 4, the assembled battery 200 includes a plurality of (typically 10 or more, preferably about 40 to 80, for example, 50) lithium ion secondary batteries (unit cells) 10 respectively. The wide surfaces of the battery case 15 are arranged in the facing direction (stacking direction) while being inverted one by one so that the positive electrode terminals 60 and the negative electrode terminals 80 are alternately arranged. A cooling plate 110 having a predetermined shape is sandwiched between the arranged cells 10. The cooling plate 110 functions as a heat dissipating member for efficiently dissipating the heat generated in each unit cell 10 during use, and preferably a cooling fluid (typically air) between the unit cells 10. ) (For example, a shape in which a plurality of parallel grooves extending vertically from one side of the rectangular cooling plate to the opposite side are provided on the surface). A cooling plate made of metal having good thermal conductivity or lightweight and hard polypropylene or other synthetic resin is suitable.

  A pair of end plates (restraint plates) 120 and 120 are disposed at both ends of the unit cell 10 and the cooling plate 110 arranged as described above. One or a plurality of sheet-like spacer members 150 as length adjusting means may be sandwiched between the cooling plate 110 and the end plate 120. The unit cell 10, the cooling plate 110, and the spacer member 150 arranged above have a predetermined restraining pressure in the stacking direction by a tightening restraining band 130 attached so as to bridge between the end plates 120, 120. Restrained to join. More specifically, by tightening and fixing the end portion of the restraining band 130 to the end plate 120 with screws 155, the unit cells and the like are restrained so that a predetermined restraining pressure is applied in the arrangement direction. Thereby, restraint pressure is also applied to the wound electrode body 50 housed in the battery case 15 of each unit cell 10. In the unit cell 10 of the present embodiment, since the deformation of the battery case 15 is prevented, substantially the same restraining pressure is applied to each unit cell 10. In addition, between the adjacent unit cells 10, one positive electrode terminal 60 and the other negative electrode terminal 80 are electrically connected by a connecting member (bus bar) 140. Thus, the assembled battery 200 of the desired voltage is constructed | assembled by connecting each cell 10 in series.

  EXAMPLES Examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples.

[Test Example 1]
<Example 1>
[Preparation of separator]
A three-layer separator A in which a porous polypropylene layer was formed on both sides of a porous polyethylene layer was prepared. The thickness of the separator A was 20 μm, the length of the separator A in the longitudinal direction was 1334 mm, the length of the separator A in the width direction was 61 mm, and the mass of the separator A was 1.55 g.
Next, the separator A prepared above was immersed for 1 hour in an acetonitrile solution containing 1 mmol of copper (I) chloride-pyridine complex as a gas adsorbent with respect to 1 g of the separator in a nitrogen atmosphere at 30 ° C. and 1 atm. Thereafter, the separator A was taken out from the acetonitrile solution and dried under reduced pressure to produce a separator (gas adsorbent-carrying separator) carrying the copper (I) chloride-pyridine complex according to Example 1.

[Preparation of positive electrode]
The mass ratio of 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 is 90: 8: 2. Thus, these materials were dispersed in NMP to prepare a paste-like composition for forming a positive electrode mixture layer. The composition was applied to a positive electrode current collector (aluminum foil) having a thickness of 15 μm at a coating amount of 25 mg / cm ² per side and dried, and then subjected to a press treatment so that the mixture density was on the positive electrode current collector. A sheet-like positive electrode A on which a positive electrode mixture layer of 2.8 g / cm ³ was formed was produced.

[Preparation of negative electrode]
Weigh so that the mass ratio of natural graphite, SBR as a binder, and CMC as a thickener is 98: 1: 1, and disperse these materials in ion-exchanged water to obtain a paste-like negative electrode composite. A material layer forming composition was prepared. The composition was applied to a negative electrode current collector (copper foil) having a thickness of 10 μm and coated at a coating amount of 20 mg / cm ² on one side and dried, and then subjected to a press treatment so that the mixture density was 1 on the negative electrode current collector. A sheet-like negative electrode A on which a 4 g / cm ³ negative electrode mixture layer was formed was produced.

[Production of lithium ion secondary battery (non-aqueous electrolyte secondary battery)]
The wound electrode body according to Example 1 was fabricated by winding the gas adsorbent-carrying separator according to Example 1 between the prepared positive electrode A and negative electrode A and winding it in an elliptical shape. Electrode terminals are joined to the ends of the positive and negative electrode current collectors of the wound electrode body, and the wound electrode body is placed in an aluminum battery case having a length of 75 mm, a width of 120 mm, a thickness of 15 mm, and a case thickness of 1 mm. The assembly which concerns on Example 1 was produced by accommodating. Next, the nonaqueous electrolytic solution according to Example 1 was injected into the battery case of the assembly according to Example 1. The non-aqueous electrolyte according to Example 1 is a non-aqueous solvent having a volume ratio of EC, DMC, and EMC of 3: 4: 3, LiPF ₂ (C ₂ O ₄ ) ₂ as an additive, and LiPF ₆ as a supporting salt. Used was dissolved. The concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte according to Example 1 was 0.02 mol / L, and the concentration of LiPF ₆ was 1 mol / L. After the injection, the assembly according to Example 1 was charged and discharged for the first time. That is, under a temperature condition of 25 ° C., charging is performed at a constant current and a constant voltage up to 4.1 V at a charging rate of 1 C (4 A), and after a pause of 10 minutes, discharging is performed at a constant current up to 3 V at a discharging rate of 1 C (4 A). And paused for 10 minutes. In this way, it provided with a negative electrode on the surface of the anode active material _{LiPF 2 (C 2 O 4)} 2 derived from coating formed, thereby producing a lithium ion secondary battery according to Example 1.

<Example 2 to Example 28>
Table 1 shows the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte injected into the battery case and the amount of gas adsorbent (copper chloride (I) -pyridine complex) supported on the separator A. An assembly and a lithium ion secondary battery according to Examples 2 to 28 were produced in the same manner as in Example 1 except that these were changed. The separators according to Examples 7, 14, 21 and 28 did not carry a gas adsorbent.

[Measurement of gas generation amount]
About the assembly which concerns on the produced Examples 1-28, the volume of each assembly was measured by the Archimedes method. Then, the volume of the battery was measured by the Archimedes method for the lithium ion secondary batteries according to Examples 1 to 28 after the first charge / discharge. Then, the volume B [mL] of the assembly according to each example is subtracted from the volume A [mL] of the lithium ion secondary battery according to each example after the initial charge / discharge, respectively, and the amount of gas generated after the initial charge / discharge ( AB) [mL] was calculated. The measurement results are shown in Table 1. Moreover, the relationship between the gas generation amount [mL] after the first charge / discharge and the gas adsorbent [mmol / g] is shown in FIG. In the Archimedes method, a measurement object (in this example, an assembly and a lithium ion secondary battery) is immersed in a liquid medium (for example, distilled water or alcohol), and the buoyancy that the measurement object receives is measured. This is a method for obtaining the volume of the measurement object.

As shown in Table 1 and FIG. 6, it was confirmed that the gas generation amount was greatly reduced by loading the gas adsorbent (copper chloride (I) -pyridine complex) on the separator. That is, it was confirmed that the increase in the internal pressure of the battery case was suppressed by supporting the gas adsorbent on the separator. In addition, in a battery including the above-described aluminum battery case, when the amount of gas generated exceeds 1.7 mL, the shape of the battery case (particularly the shape in the thickness direction) is deformed, and a plurality of the batteries are set in advance. It was difficult to construct an assembled battery with the restraining force. For this reason, the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte injected into the aluminum battery case needs to be 0.02 mol / L or less. However, even if the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte injected into the battery case is further increased from 0.02 mol / L by supporting the gas adsorbent on the separator, the battery Only a small amount of gas was present in the case, and it was confirmed that an increase in the internal pressure of the battery case could be suppressed.

[Test Example 2]
<Examples 29 to 34>
Table 2 shows the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte injected into the battery case and the amount of gas adsorbent (copper chloride (I) -pyridine complex) supported on the separator A. Except having changed into the thing, it carried out similarly to Example 1, and produced the lithium ion secondary battery which concerns on Example 29-Example 34. The separator according to Example 34 did not carry a gas adsorbent.

[Initial reaction resistance measurement]
The lithium ion secondary batteries according to Examples 29 to 34 manufactured as described above were subjected to an appropriate conditioning treatment at a temperature of 25 ° C. (constant current and constant voltage up to 4.1 V at a charge rate of 0.1 C). After performing an operation of charging and an operation of repeating a constant current and a constant voltage discharge to 3.0 V at a discharge rate of 0.1 C three times), the state of charge was adjusted to 40% SOC. And the alternating current impedance measurement was performed at a frequency of 0.001 Hz to 100,000 Hz under the temperature condition of −30 ° C. with respect to the lithium ion secondary batteries of Examples 29 to 34, and the obtained Cole-Cole plot of 0.01 Hz to The diameter of an arc (semicircle) at 30 Hz was measured, and the value was defined as the initial reaction resistance [Ω]. The obtained resistance values are shown in Table 2 and FIG.

[Measurement of reaction resistance after storage]
About the lithium ion secondary battery which concerns on Example 29-Example 34 after measuring the said initial stage reaction resistance, after adjusting to SOC90%, it preserve | saved for 30 days under 60 degreeC temperature conditions. After the lithium ion secondary batteries according to Examples 29 to 34 after storage were adjusted to SOC 40%, AC impedance measurement was performed at a frequency of 0.001 Hz to 100,000 Hz under a temperature condition of −30 ° C., and the obtained Cole− The diameter of an arc (semicircle) at 0.01 Hz to 30 Hz in the Cole plot was measured, and the value was defined as reaction resistance [Ω] after storage. The obtained resistance values are shown in Table 2 and FIG.

[Capacity maintenance rate measurement]
About the lithium ion secondary battery which concerns on the said Examples 29-34, the capacity | capacitance maintenance factor [%] after preserve | saving for 30 days on 60 degreeC temperature conditions was measured. First, under the temperature condition of 25 ° C., the lithium ion secondary batteries according to Examples 29 to 34 were subjected to constant current and constant voltage for 3 hours to 4.1 V at a charge rate of 1 C, and rested for 10 minutes. Next, constant current discharge was performed for 6 hours to 3 V at a discharge rate of 1/3 C, and rested for 10 minutes. Further, constant current and constant voltage discharge was performed for 4 hours to 3 V at a discharge rate of 1/3 C, and rested for 10 minutes. The capacity obtained at this time was defined as the initial battery capacity. Next, each lithium ion secondary battery whose initial battery capacity was measured was adjusted to SOC 90% and then stored for 30 days under a temperature condition of 60 ° C. For the lithium ion secondary batteries according to Examples 29 to 34 after storage, the battery capacity after storage (battery capacity after storage) was measured by the same method as the method for measuring the initial battery capacity. Here, the following formula: {(battery capacity after storage) / (initial battery capacity)} × 100 was defined as the capacity retention rate [%] after 30 days storage. The measurement results are shown in Table 2 and FIG.

As shown in Table 2 and FIG. 7, regarding the initial reaction resistance, when the concentration of LiPF ₂ (C ₂ O ₄ ) ₂ contained in the nonaqueous electrolytic solution is 0.02 mol / L to 0.04 mol / L. It was confirmed to show a low value. As for the after storage reaction resistance, non-aqueous concentration of _{LiPF 2 (C 2 O 4)} 2 contained in the electrolytic solution was found to exhibit a low value in case of more than 0.02 mol. Further, as shown in Table 2 and FIG. 8, for the capacity retention rate, the _{LiPF 2 (C 2 O 4)} 2 contained in the nonaqueous electrolytic solution concentration of 0.02mol / L~0.04mol / L It was confirmed that the case shows a high value. From the above, it was confirmed that high battery performance was exhibited when the concentration of LiPF ₂ (C ₂ O ₄ ) ₂ contained in the non-aqueous electrolyte was 0.02 mol / L to 0.04 mol / L.

  The nonaqueous electrolyte secondary battery according to the present invention or the nonaqueous electrolyte secondary battery obtained by the production method is excellent in battery performance because a stable film is formed on the surface of the negative electrode active material. For this reason, it can be suitably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. Moreover, in the non-aqueous electrolyte secondary battery according to the present invention, a predetermined shape of the battery case is maintained by suppressing an increase in the internal pressure of the battery case. For this reason, the assembled battery formed by connecting a plurality of the batteries in series can be stably constructed. Therefore, as schematically shown in FIG. 5, the present invention provides a vehicle (typically) having such a lithium ion secondary battery 10 (typically, a battery pack 200 formed by connecting a plurality of such batteries 10 in series) as a power source. Is provided with an automobile, particularly an automobile equipped with an electric motor such as a hybrid vehicle, an electric vehicle, and a fuel vehicle.

10 Lithium ion secondary battery (non-aqueous electrolyte secondary battery)
15 Battery Case 20 Opening 25 Lid 30 Case Body 40 Safety Valve 45 Inlet 48 Sealing Plug 50 Winding Electrode Body 60 Positive Electrode Terminal 62 Positive Electrode Current Collector 63 Positive Electrode Mixing Layer Non-Forming Portion 64 Positive Electrode 66 Positive Electrode Mixing Layer 80 Negative electrode terminal 82 Negative electrode current collector 83 Negative electrode mixture layer non-formed portion 84 Negative electrode 86 Negative electrode mixture layer 90 Gas adsorbent carrying separator 100 Vehicle (automobile)
200 batteries

Claims (11)

A non-aqueous electrolyte secondary battery,
A positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and an electrode body including a separator interposed between the positive electrode and the negative electrode, a non-aqueous electrolyte, and the electrode body and the non-aqueous electrolyte are accommodated A battery case, and
A film containing at least one of phosphorus and boron is formed on the surface of the negative electrode active material,
The separator is a non-aqueous electrolyte secondary battery in which a copper (I) chloride-pyridine complex is supported as a gas adsorbent.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the supported amount of the copper (I) chloride-pyridine complex is 1 mmol or more per 1 g of the separator.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte includes an oxalato complex compound containing at least one of phosphorus and boron as a constituent element and a non-aqueous solvent. The non-aqueous electrolyte secondary battery according to claim 3, wherein the oxalato complex compound is LiPF ₂ (C ₂ O ₄ ) ₂ .   5. The non-aqueous electrolysis according to claim 1, wherein the positive electrode active material is a lithium transition metal composite oxide, and the negative electrode active material is a carbon material having a graphite structure at least in part. Liquid secondary battery. A method for producing a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte,
Preparing a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material;
Supporting the copper chloride (I) -pyridine complex on the separator by immersing the separator in a solution containing the copper chloride (I) -pyridine complex as a gas adsorbent;
Producing an electrode body by interposing a separator carrying the copper chloride (I) -pyridine complex between the prepared positive electrode and the prepared negative electrode;
Producing an assembly in which the electrode body is housed in a battery case;
Injecting a non-aqueous electrolyte containing the oxalato complex compound containing at least one of phosphorus and boron as a constituent element and a non-aqueous solvent into the battery case;
Charging the assembly to a predetermined charging voltage and then discharging to a predetermined discharging voltage;
A method for producing a non-aqueous electrolyte secondary battery.   The amount of the copper chloride (I) -pyridine complex contained in the solution is adjusted so that the amount of the copper chloride (I) -pyridine complex supported on the separator is 1 mmol or more per 1 g of the separator. The manufacturing method according to claim 6. The manufacturing method according to claim 6 or 7, wherein LiPF ₂ (C ₂ O ₄ ) ₂ is used as the oxalato complex compound. The manufacturing method according to claim 8, wherein the concentration of LiPF ₂ (C ₂ O ₄ ) _{2 in} the non-aqueous electrolyte is 0.02 mol / L to 0.04 mol / L.   10. The production method according to claim 6, wherein a lithium transition metal composite oxide is used as the positive electrode active material, and a carbon material having a graphite structure at least partially is used as the negative electrode active material.   A non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the unit cell is an assembled battery as a power source for driving a vehicle in which a plurality of unit cells are electrically connected to each other. The assembled battery in which the nonaqueous electrolyte secondary battery obtained by the battery or the manufacturing method as described in any one of Claims 6 to 10 is used.

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