JP4986021B2 - Laminated non-aqueous secondary battery - Google Patents

Description

  The present invention relates to a laminated non-aqueous secondary battery, and more particularly, a laminated non-aqueous secondary battery suitable for use as a power source for portable electronic devices, electric vehicles, electric assist bicycles, electric motorcycles, road leveling and the like. It relates to batteries.

  A lithium ion secondary battery, which is a type of non-aqueous secondary battery, is widely used as a power source for portable devices such as mobile phones and notebook personal computers because of its high energy density. In addition, the importance of secondary batteries that can be recharged is increasing due to considerations for environmental issues. In addition to portable devices, application to automobiles, electric wheelchairs, household and commercial power storage systems is being considered. Yes.

  2. Description of the Related Art In recent years, hybrid vehicles (HEV) that use both battery and gasoline due to environmental problems, assist bicycles that support power with batteries, electric vehicles and motorcycles that use batteries for all power, have become widespread. Compared to the power source of small portable devices such as mobile phones, the power source of these medium-sized and large-sized devices requires a high-power secondary battery having a large capacity.

  Lithium ion secondary batteries include cylindrical batteries and laminated batteries. Laminated batteries have a sealing resin layer (heat-fusible resin layer, eg, polyethylene layer) on one side of a metal sheet, and a resin layer (eg, polyethylene terephthalate layer) with excellent mechanical strength on the other side. A laminated electrode body in which a sheet-like positive electrode and a sheet-like negative electrode are overlapped with a separator in a laminate film outer package configured such that the sealing resin layer side is on the inside, etc. Since the energy density per weight is higher than that of a cylindrical battery and the degree of freedom in size and thickness is large, various shapes are manufactured.

  In a laminated battery, sealing after the above electrode body and non-aqueous electrolyte (non-aqueous electrolyte) are accommodated in the laminate film outer package is usually performed by welding the sealing resin layers inside the outer package. Yes. Therefore, the end of the sealing resin layer is exposed outside the battery at the place where the welding sealing is performed, but moisture or oxygen in the outside air flows into the battery through the sealing resin layer or inside the battery. The non-aqueous electrolyte may evaporate out of the battery.

When the non-aqueous electrolyte in the battery evaporates, the electrode reaction area decreases, leading to an increase in internal resistance and battery characteristics to deteriorate. Further, when moisture flows into the battery, for example, when a non-aqueous electrolyte solution in which a fluorine atom-containing lithium salt such as LiPF ₆ or LiBF ₄ is dissolved in an organic solvent is used, these lithium salt and moisture Hydrogen fluoride is generated by this reaction. This hydrogen fluoride is strongly acidic and may adversely affect the reliability of the battery, such as corroding the electrode terminal surface and causing leakage of the nonaqueous electrolyte.

  The adverse effect of the movement of substances (moisture and oxygen outside the battery, non-aqueous electrolyte inside the battery) between the inside and outside of the battery through the outer edge of the sealing resin layer as described above is due to the use of laminated non-aqueous secondary batteries. The longer the period, the more prominent. In the past, the above-mentioned adverse effects were not a significant problem in relation to the period of use of laminated non-aqueous secondary batteries, but the usage period of laminate-type non-aqueous secondary batteries is very long. It is getting longer. Therefore, in the laminate type non-aqueous secondary battery, it is required to prevent the above-described adverse effects, ensure sufficient reliability, and prolong its life.

  Under such circumstances, various methods for suppressing the movement of substances between the inside and outside of the battery through the outer end portion of the sealing resin layer as described above have been proposed.

  For example, in Patent Documents 1 to 3, the sealing part of the laminate film exterior body has a special structure to suppress the intrusion of moisture from the outside of the battery or prevent the non-aqueous electrolyte from escaping in the battery. The technique to do is disclosed.

  Further, Patent Documents 4 to 7 disclose a material that can prevent moisture from entering the outside of the battery through the sealing portion of the laminate film outer package and transpiration of the non-aqueous electrolyte in the battery. Techniques such as disposing at the stop portion are disclosed.

  That is, Patent Document 4 discloses a technique for depositing a metal or an inorganic oxide on the metal foil side of a heat-fusible film (sealing resin layer) in a laminate film outer package, and Patent Document 5 discloses a thermoplastic resin laminate layer. A technique for blending a water-capturing agent into (sealing resin layer), a technique for arranging a water-absorbing member in a sealing part in Patent Document 6, and an outer edge end face of a sealing part of a laminate film outer package in Patent Document 7 The techniques for applying a water-repellent substance having a specific surface tension are described respectively.

  However, in the techniques proposed in Patent Documents 1 to 3, as long as the sealing portion of the laminate film exterior body has a special structure, the productivity of the battery must be sacrificed to some extent, and is a simple method. Is not good.

  In addition, in the laminate type non-aqueous secondary battery, it is required to suppress the movement of the substance between the inside and outside of the battery in the sealing part of the laminate film outer package and to ensure the mechanical strength in the sealing part. As proposed in Documents 4 to 7, when various materials are arranged in the sealing resin layer or the sealing portion, parameters to be examined for ensuring the mechanical strength of the sealing portion are as follows. Since it becomes very large, it is difficult to say that it is a simple method.

  Therefore, in the laminate type non-aqueous secondary battery, in order to suppress the movement of the substance between the inside and outside of the battery in the sealing portion of the laminate film outer package, in addition to ensuring its effect, it is a simple method. It is required to be.

  For example, if the sealing area of the sealing part of the laminate film outer package (sealing area in plan view of the battery) is increased and the distance from the end of the sealing part to the inside of the battery is increased, the battery can be obtained with a simple technique. Although the movement of the substance between the inside and the outside can be suppressed, in this case, there is also a problem that the energy density per volume of the battery decreases as the sealing portion increases.

JP 2000-223090 A JP 2001-60453 A JP 200431288 A JP 2002-25511 A JP 2002-134074 A JP 2003-187762 A JP 2005-196979 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated non-aqueous secondary battery having good reliability, a long life, and a high energy density.

  The laminate type nonaqueous secondary battery of the present invention is characterized by having the following aspect (1) or (2).

(1) A positive electrode sheet in which a positive electrode active material-containing layer is formed on a positive electrode current collector and a negative electrode sheet in which a negative electrode active material-containing layer is formed on a negative electrode current collector are laminated via a separator. A laminated non-aqueous secondary battery in which a laminated electrode body and a non-aqueous electrolyte are accommodated in a cylindrical laminated film outer package in which an upper end and a lower end are welded and sealed.

(2) A positive electrode sheet in which a positive electrode active material-containing layer is formed on a positive electrode current collector and a negative electrode sheet in which a negative electrode active material-containing layer is formed on a negative electrode current collector are laminated via a separator. A laminate-type non-aqueous secondary battery in which a laminated electrode body and a non-aqueous electrolyte are accommodated in a rectangular laminate film outer package in which at least three sides are welded and sealed, and the sealing resin in the laminate film outer package A non-aqueous secondary battery in which A / C ≦ 1/30 where A is the area of the portion exposed to the outside of the battery and A (cm ² ) and the battery capacity is C (mAh).

  When the area where the sealing resin is exposed to the outside of the battery is constant, the amount of moisture and oxygen that penetrates into the battery per hour and the amount of nonaqueous electrolyte (nonaqueous electrolyte) that evaporates out of the battery. The amount per hour is within a certain range, and the degree of deterioration of the electrodes and nonaqueous electrolyte present in the battery due to moisture and oxygen entering the battery and the nonaqueous electrolyte transpired out of the battery is also to some extent. Presumed to fall within the range.

  In the aspect of (1) of the present invention, the sealing resin is exposed to the outside of the battery by configuring the battery using a cylindrical laminate film outer package that can have a sealed portion smaller than a normal laminate film outer package. Reducing the area to be transferred, reducing the amount of movement of moisture (oxygen outside the battery and nonaqueous electrolyte in the battery) between the inside and outside of the battery per hour, and among the electrodes and nonaqueous electrolyte existing in the battery, The proportion of parts that deteriorate over time is reduced.

  In the aspect (2) of the present invention, the amount of the area where the sealing resin is exposed to the outside of the battery per battery capacity is used while using a normal laminate film outer package in which the sealing portion is difficult to reduce. Is limited to a predetermined value or less. In order to increase the battery capacity, it is necessary to increase the amount of electrodes and nonaqueous electrolyte in the battery. Therefore, by limiting the amount per area of the battery where the sealing resin is exposed outside the battery to a predetermined value or less, the amount of movement of the substance between the inside and outside of the battery per hour, The balance with the amount of the nonaqueous electrolyte is adjusted to reduce the proportion of the electrode and nonaqueous electrolyte present in the battery that deteriorates over time.

  According to the present invention, a laminated non-aqueous secondary battery having good reliability and a long service life can be provided by the above operation.

  Further, in the battery of the present invention, as described above, since the sealing portion not involved in power generation is made as small as possible in relation to the battery capacity, an improvement in reliability and a longer life are achieved. The energy density per battery volume can also be increased.

  According to the present invention, it is possible to provide a laminated non-aqueous secondary battery having good reliability, a long life, and a high energy density.

  The laminated nonaqueous secondary battery of the present invention is a laminate electrode body in which a positive electrode sheet and a negative electrode sheet are laminated via a separator, and is enclosed in a laminate film outer package. As a laminate film exterior body, a laminate film having a structure in which at least one layer of a sealing resin film (sealing resin layer) made of an insulating heat-fusible resin is laminated on one side or both sides of a metal sheet having air-blocking properties The thing comprised by these is mentioned.

  The metal sheet constituting the laminate film is not particularly limited as long as it can prevent the movement of substances between the inside and outside of the battery, and a sheet made of a known metal material can be used. Specifically, the sheet | seat comprised by metal materials, such as aluminum, stainless steel, nickel, copper, is mentioned.

  From the viewpoint of better preventing the movement of the substance between the inside and outside of the battery, the thickness of the metal sheet relating to the laminate film is preferably 10 μm or more, more preferably 30 μm or more. However, if the metal sheet is too thick, it may not be possible to sufficiently transfer heat to the sealing resin layer at the time of welding and sealing the laminate film exterior body, and the airtight reliability after welding and sealing may be reduced. In addition, the laminate film outer package itself becomes thick and the energy density of the battery tends to decrease. Therefore, the thickness of the metal sheet is preferably 150 μm or less, and more preferably 100 μm or less.

  The insulating heat-fusible resin for forming the sealing resin layer is not particularly limited as long as it can seal the laminate film outer package by heat-sealing (welding). Can be used. Specifically, polyolefins such as polyethylene, maleic acid-modified polyethylene, polypropylene, maleic acid-modified polypropylene; polyesters such as heat-fusible polyethylene terephthalate; heat-fusible polyimides; polymethyl methacrylate; ionomer resins; And a copolymer (such as ethylene-propylene copolymer) composed of two or more monomers for forming these resins.

  The thickness of the sealing resin layer according to the laminate film is preferably 20 μm or more and more preferably 30 μm or more from the viewpoint of further increasing the mechanical strength after welding. However, if the sealing resin layer is too thick, the area of the sealing resin exposed to the outside of the battery after welding is increased, and the airtight reliability may be lowered. Therefore, the thickness of the sealing resin layer is preferably 100 μm or less, and more preferably 80 μm or less.

  The laminate film exterior body having the above-described configuration has good gas barrier properties and light blocking properties due to the metal sheet, and can be easily welded and sealed with the sealing resin layer.

  In addition, the laminate film constituting the laminate film exterior body has the above-described sealing resin layer on one side of the metal sheet (the surface that becomes the inside of the battery), and mechanical strength on the other side (the surface that becomes the outside of the battery). It is preferable to have a layer (outer layer) made of an excellent resin. The durability of the battery can be enhanced by using a laminate film outer package having such an outer layer. Examples of the resin that can form the outer layer in this case include polyesters such as polyethylene terephthalate, nylons such as nylon 66, and the like.

  The thickness of the outer layer is preferably 20 μm or more, and more preferably 30 μm or more, from the viewpoint of more effectively exerting the effect of providing the outer layer. However, if the outer layer is too thick, the energy density of the battery tends to decrease. Therefore, the thickness is preferably 100 μm or less, and more preferably 80 μm or less.

  FIG. 1 schematically shows an example of a laminated nonaqueous secondary battery of the present invention according to the aspect (1). 1A is a plan view, and FIG. 1B is a side view. In the battery of FIG. 1, a laminated film outer body 10 that is cylindrical and has no portion where the sealing resin related to the sealing resin layer is exposed in the body portion is used, and a laminated electrode body is provided in the laminated film outer body 10. In addition, the non-aqueous electrolyte is accommodated and welded and sealed with the sealing portions 20 and 20 at the upper and lower ends of the laminate film outer package 10. In FIG. 1, 30 is a positive terminal and 40 is a negative terminal.

  FIG. 2 shows a partially enlarged view of the side surface of the battery of FIG. In FIG. 2, 11 is a metal sheet according to the laminate film exterior body, 12 is a sealing resin layer according to the laminate film exterior body, 13 is an outer layer according to the laminate film exterior body, and the sealing resin layer 12 is the upper side in the figure. The sealing resin layer provided on the lower side of the metal sheet 11 and the sealing resin layer provided on the upper side of the lower metal sheet 11 in the figure are welded and sealed to form a single layer. Yes. As shown in FIG. 2, in the sealing portion of the laminate film outer package, there is a portion where the sealing resin is exposed to the outside of the side surface, which is a path of mass transfer between the inside and outside of the battery. It has become.

  As shown in FIG. 1, the laminate film exterior body used in the battery of the aspect (1) can be sealed by welding only its upper and lower ends. Therefore, in the battery of the aspect of (1), the area of the portion where the sealing resin that becomes a path for substances inside and outside the battery (water and oxygen outside the battery and the nonaqueous electrolyte inside the battery) is exposed outside the battery is reduced. It becomes possible. Therefore, the amount of moisture and oxygen entering the outside air through the above part and the amount of non-aqueous electrolyte transpiration are suppressed, and the proportion of the electrode and non-aqueous electrolyte existing in the battery that deteriorates over time is reduced. be able to.

  The laminate film exterior body used in the battery according to the aspect (1) is sealed in a plan view after welding sealing from the viewpoint of reducing the area of the portion where the sealing resin is exposed outside the battery after welding sealing. It is preferable that the length of the part is shorter than the height of the body part.

  The laminate film outer package used in the battery of the aspect (1) is, for example, JP-A-7-132949, JP-A-7-132950, JP-A-8-91397, JP-A-8-104340. It can be produced by a method disclosed in Japanese Patent Laid-Open No. 8-1515959.

  FIG. 3 schematically shows an example of the laminated nonaqueous secondary battery of the present invention according to the aspect (2). 3A is a plan view, and FIG. 3B is a side view. In FIG. 3, components having the same functions as those in FIG. 1 are denoted by the same reference numerals (the same applies to the following drawings).

  In the battery of FIG. 3, in the laminate film exterior body, two vertical sides in the drawing and three sides of the terminals 30 and 40 side are welded and sealed as a sealing portion 20. In the figure, the side portions facing the sides on the terminals 30 and 40 side are the folded portions (folded portions) of the laminate film, but the sides facing the terminals 30 and 40 side are also the sealing portions. A sealing type laminate film outer package may be used.

In the laminated nonaqueous secondary battery of the present invention according to the aspect (2), a rectangular laminate film outer package of a type in which three sides are welded and sealed as shown in FIG. 2, or a type in which four sides are welded and sealed. However, it is difficult to reduce the portion where the sealing resin is exposed to the outside of the battery. Therefore, in the battery according to the aspect (2), the relationship between the area A (cm ² ) of the portion where the sealing resin is exposed outside the battery and the battery capacity C (mAh) is expressed as A / C ≦ 1/30. The amount of movement of the material between the inside and outside of the battery through the exposed portion of the sealing resin outside the battery (that is, the time of the substance that causes deterioration of the electrodes and nonaqueous electrolyte in the battery) The amount of electrodes and nonaqueous electrolyte parts that deteriorate over time is reduced by increasing the battery capacity and increasing the amount of electrodes and nonaqueous electrolyte in the battery. .

  That is, in the battery of the aspect (2), when A / C exceeds 1/30, the ratio of electrodes that deteriorate per unit time increases, and the reliability of the battery is impaired and the life is shortened. . The value of A / C is more preferably 1/50 or less. The smaller the value of A / C, the better. However, the area A depends on the form of the laminate film outer package, and on the other hand, the battery capacity that can be secured by a specific form of the laminate film outer package is limited. The lower limit value of C is usually about 1/300.

  In the laminated nonaqueous secondary battery of the aspect (2), a rectangular laminate film outer package is used in plan view. This “square” includes squares and rectangles, for example, four corners. A shape having one or more curved lines and a shape having one or more corners cut off are also included.

  In the battery of the aspect (1), the A / C value is 1/30 or less, more preferably 1/100 or less, for the same reason as the battery of the aspect (2). The above is desirable.

  In addition, although the structure of the non-aqueous secondary battery of this invention was demonstrated so far using FIGS. 1-3, the structure and structure of the laminate type non-aqueous secondary battery of this invention are these FIGS. 1-3. It is not necessarily limited to what is illustrated in FIG. 1 to 3 are merely illustrated for the purpose of facilitating understanding of the configuration of the laminated nonaqueous secondary battery of the present invention, and the size of each component is not necessarily accurate.

In the positive electrode (positive electrode sheet) according to the laminated nonaqueous secondary battery of the present invention, the positive electrode active material-containing layer containing a positive electrode active material, a conductive additive, a binder and the like is on the current collector (one or both surfaces of the current collector). ). As the positive electrode active material, for example, lithium cobalt oxide such as LiCoO ₂ , lithium manganese oxide such as LiMn ₂ O _4, and lithium composite oxide exemplified by lithium nickel oxide such as LiNiO ₂ are preferably used. Co, Mn, or Ni of these active materials may be substituted with other elements, respectively. Moreover, these active materials may be used individually by 1 type, and may use 2 or more types together.

  As the positive electrode current collector, an aluminum foil having a thickness of 5 to 60 μm is suitable. The positive electrode tab may leave an exposed portion of the current collector without forming a positive electrode active material-containing layer in a part of the positive electrode current collector, and may be used as a positive electrode tab. You may connect and provide.

  In producing the positive electrode, the positive electrode active material, a conductive additive such as graphite, acetylene black, and carbon black, and a positive electrode mixture containing a binder such as polyvinylidene fluoride and polytetrafluoroethylene are mixed with N-methyl. A paste-like or slurry-like composition uniformly dispersed using a solvent such as -2-pyrrolidone (NMP) is prepared (the binder may be dissolved in the solvent), and this composition is collected into the positive electrode current collector. The method of apply | coating on a body, drying, and adjusting the thickness and density of a positive electrode active material content layer by press processing as needed can be employ | adopted. However, the manufacturing method of the positive electrode according to the present invention is not limited to the above method, and other methods may be adopted.

  The thickness of the positive electrode active material-containing layer in the positive electrode is preferably 30 to 300 μm per side. Moreover, it is preferable that content of each structural component in a positive electrode active material content layer shall be 85-95 mass% of positive electrode active materials, 1-5 mass% of conductive support agents, and 2-5 mass% of binders.

  The negative electrode (negative electrode sheet) according to the laminated nonaqueous secondary battery of the present invention has a negative electrode active material-containing layer containing a negative electrode active material, a binder, and a conductive auxiliary agent as necessary. It is formed on one side or both sides of the electric body. Although it does not specifically limit as a negative electrode active material, It is preferable to use carbon materials, such as graphites which can dope and dedope lithium ion, pyrolytic carbons, cokes, and glassy carbons.

  It is preferable to use a copper foil having a thickness of 5 to 60 μm for the negative electrode current collector. The negative electrode tab may leave an exposed portion of the current collector without forming a negative electrode active material-containing layer in a part of the negative electrode current collector, and may be used as a negative electrode tab. You may connect and provide.

  In preparing the negative electrode, a negative electrode mixture containing the above negative electrode active material, a binder such as polyvinylidene fluoride and polytetrafluoroethylene, and a conductive aid such as graphite, acetylene black, and carbon black as necessary. A paste-like or slurry-like composition uniformly dispersed using a solvent such as NMP is prepared (the binder may be dissolved in the solvent), and this composition is applied onto the negative electrode current collector. Then, a method of adjusting the thickness and density of the negative electrode active material-containing layer by pressing may be employed as necessary. However, the manufacturing method of the negative electrode according to the present invention is not limited to the above method, and other methods may be adopted.

  The thickness of the negative electrode active material-containing layer in the negative electrode is preferably 30 to 300 μm per side. Moreover, it is preferable that content of each structural component in a negative electrode active material content layer shall be negative electrode active material: 85-95 mass%, binder: 2-5 mass%, and when using a conductive support agent, it is a negative electrode The content of the conductive additive in the active material-containing layer is preferably 1 to 5% by mass.

Examples of the nonaqueous electrolyte used in the laminated nonaqueous secondary battery of the present invention include LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF _{3 in} organic solvents such as dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, and ethylene carbonate. it can be used a material obtained by dissolving a solute such as SO _3.

  The non-aqueous electrolyte can also be used by mixing a resin, a cross-linking agent, etc., and gelling or solidifying. By making the electrolyte into a gel, the components of the electrolyte decompose when the battery is overcharged, and gas is generated. This gas causes separation between the separator layers (for example, a nonwoven fabric and a porous material described later). In the case of a separator composed of a quality film), a gap is formed between the separator and the negative electrode, and thus the safety of the battery can be further improved.

  Further, at least one additive selected from an aromatic compound having a benzene ring and a phosphazene derivative may be added to the non-aqueous electrolyte. The aromatic compound having a benzene ring is not particularly limited as long as it decomposes in the vicinity of 4.2 to 4.7 V to generate gas and polymerizes on the positive electrode surface to form a film. Examples thereof include alkylbenzenes such as xylene and cyclohexylbenzene, aromatic halogens, aromatic amines, aromatic carboxylic acids, and biphenyl. Among the above aromatic compounds, biphenyl, cyclohexylbenzene, or derivatives thereof (fluorine-substituted products and the like) are preferably used from the viewpoint of film forming ability. As the aromatic compound having a benzene ring, those exemplified above may be used alone or in combination of two or more.

  As the phosphazene derivative that can be added to the electrolytic solution, either a cyclic type or a chain type can be used. In consideration of battery characteristics such as load characteristics, the phosphazene derivative is particularly represented by the following general formula (1). An annular structure is preferably used.

In the general formula (1), the side chains R _{1 to} R ₆ are
₍₁₎ -CH 3, alkyl group having 1 to 10 carbon atoms, such as _-CH 2 CH ₃ (although some hydrogen or all may be substituted with a halogen element such as fluorine);
(2) Alkoxy groups having 1 to 10 carbon atoms such as —OCH ₃ , —OCH ₂ CH ₃ , —OC ₆ H ₅ , —OCH ₂ OCH ₂ CH ₃ (however, part or all of hydrogen is halogen such as fluorine) May be substituted with an element);
_{(3) -COOCH 3, -COOCH 2} CH 3, -COOC 6 H 5 carboxyl group having 1 to 10 carbon atoms such as (although some hydrogen or all may be substituted with a halogen element such as fluorine );
(4) Carbonyl group having 1 to 10 carbon atoms such as —COCH ₃ , —COCH ₂ CH ₃ , —COC ₆ H ₅ (however, part or all of hydrogen may be substituted with a halogen element such as fluorine) );
(5) an aryl group having 1 to 12 carbon atoms such as —C ₆ H ₅ , —C ₆ H ₄ CH ₃ , —C ₆ H ₅ (CH ₃ ) ₂ (provided that part or all of hydrogen is fluorine or the like) Optionally substituted with a halogen element);
(6) A vinyl group having 1 to 10 carbon atoms such as —CH═CH ₂ , —CH═CH ₂ C ₂ H ₅ , —CH═CH ₂ C ₆ H ₅ (however, part or all of hydrogen is fluorine, etc.) May be substituted with a halogen element);
(7) Hydrogen or halogen elements such as fluorine and chlorine;
Which may be the same as or different from each other.

  When the above additives are used, the addition amount in the electrolytic solution is preferably 3 to 15% by mass in the total amount of the electrolytic solution for aromatic compounds, and 1 to 15% by mass in the total amount of the electrolytic solution for phosphazene derivatives. It is good to do. One of these additives may be used alone, or two or more different additives may be used in combination.

  As the separator according to the battery of the present invention, a known separator, for example, a separator made of a porous film or a nonwoven fabric made of polyolefin such as polyethylene, polypropylene, or a fusion product of polyethylene and polypropylene can be used.

  In the battery of the present invention, the separator has a rectangular non-woven fabric made of a material having a melting point of 200 ° C. or higher and a rectangular porous film made of a material having a melting point of 140 ° C. or lower, A square non-woven fabric in the separator is disposed on both sides of the positive electrode sheet, and the non-woven fabric on the lower side of the positive electrode sheet and the non-woven fabric on the upper side are fixed on at least three sides. It is preferable that a rectangular porous film in the separator is fixed to at least one of the sides.

  When a separator having a rectangular non-woven fabric composed of a material having a melting point of 200 ° C. or higher and a rectangular porous film composed of a material having a melting point of 140 ° C. or lower is disposed and used as described above, For example, even in a high temperature environment of about 150 ° C., the non-woven fabric present so as to wrap around the positive electrode sheet in the separator is made of a material having a high melting point and does not thermally shrink. Therefore, even in a high temperature environment as described above, the occurrence of a short circuit due to the positive electrode being exposed and in contact with the negative electrode is suppressed, and thermal runaway of the battery is suppressed. Also, in a high temperature environment as described above, the so-called shutdown function that the porous film constituting the separator melts, fills the pores of the porous film and the voids of the nonwoven fabric, and blocks the movement of lithium ions in the separator. Is demonstrated. Moreover, since the porous film is fixed only by the nonwoven fabric and its one side, even if the porous film shrinks before melting, the nonwoven fabric in contact with the positive electrode shrinks following the shrinkage of the porous film. The shape is maintained without being deformed. Therefore, in the battery using the separator, the safety can be further enhanced by these actions.

  Moreover, in the above separator, the lower nonwoven fabric and the upper nonwoven fabric of the positive electrode are fixed on at least three sides, and at least one of these nonwoven fabrics and the porous film are fixed. Therefore, when the battery is manufactured, when the positive electrode, the negative electrode, and the separator are laminated to form a laminated electrode body, the positive electrode is not displaced in the separator, and thus the battery can be manufactured with high yield. Battery productivity can also be increased.

  In a separator having a rectangular non-woven fabric made of a material having a melting point of 200 ° C. or higher and a rectangular porous film made of a material having a melting point of 140 ° C. or lower, the non-woven fabric has a melting point, that is, JIS K 7121 The melting temperature measured using a differential scanning calorimeter (DSC) is made of a material having a melting point of 200 ° C. or higher, and is disposed on the upper and lower surfaces of the positive electrode sheet. Specifically, the material constituting the nonwoven fabric is preferably polyarylate, polyethylene terephthalate, polybutylene terephthalate, etc., and the nonwoven fabric may be composed of only one of these, or the nonwoven fabric may be used in combination of two or more. May be configured.

  The thickness of the nonwoven fabric is preferably 5 μm or more from the viewpoint of more effectively preventing the occurrence of a short circuit. On the other hand, if the nonwoven fabric is too thick, the battery becomes thick and the energy density per volume may decrease or the high rate discharge characteristics may decrease, so the thickness of the nonwoven fabric is preferably 50 μm or less, More preferably, it is 25 μm or less.

  Further, the air permeability of the nonwoven fabric is a Gurley value measured by a method defined in JIS P 8117, preferably 300 s / 100 ml or less, and more preferably 250 s / 100 ml or less. If the air permeability of the nonwoven fabric is too large, the ion permeability may be reduced. On the other hand, if the air permeability is too small, the strength of the nonwoven fabric is reduced. Therefore, the air permeability of the nonwoven fabric is preferably 100 s / 100 ml or more. The air permeability of the nonwoven fabric can be controlled by adjusting the thickness and porosity of the nonwoven fabric.

  Furthermore, the porosity of the nonwoven fabric is preferably 30% or more, and more preferably 45% or more, from the viewpoint of ensuring good ion permeability. On the other hand, if the porosity is too large, the strength of the nonwoven fabric may be insufficient. Therefore, the porosity of the nonwoven fabric is preferably 80% or less, and more preferably 70% or less.

  In addition, the porosity of the nonwoven fabric referred to in the present specification and the porosity of the porous film described later are obtained by cutting out a sample of a certain area, measuring its weight and thickness, and calculating from these measured values. Value.

  In a separator having a rectangular nonwoven fabric made of a material having a melting point of 200 ° C. or higher and a rectangular porous film made of a material having a melting point of 140 ° C. or lower, the porous film has a melting point, that is, JIS K In accordance with the provisions of 7121, the melting temperature measured using a differential scanning calorimeter (DSC) is made of a material having a melting point of 140 ° C. or higher, and is formed on at least one of the nonwoven fabrics arranged on the upper and lower surfaces of the positive electrode. Arranged and fixed. Note that if the melting point of the constituent material of the porous film is too low, a shutdown phenomenon may occur in the operating temperature range of the battery.

  Specific examples of the material constituting the porous film include polyolefin such as polyethylene and copolymer polypropylene (ethylene-propylene copolymer, etc.), and the porous film is composed of only one of these materials. It may be composed of two or more.

  The thickness of the porous film is preferably 5 μm or more from the viewpoint of more effectively preventing the occurrence of a short circuit. On the other hand, if the porous thickness is too thick, the battery becomes thick and the energy density per volume may decrease or the high rate discharge characteristics may decrease, so the porous thickness may be 50 μm or less. Preferably, it is more preferably 25 μm or less.

  Further, the air permeability of the nonwoven fabric is a Gurley value measured by a method prescribed in JIS P 8117, preferably 600 s / 100 ml or less, and more preferably 500 s / 100 ml or less. If the air permeability of the porous film is too large, the ion permeability may be reduced. On the other hand, if the air permeability is too small, the strength of the porous film becomes small. Therefore, the air permeability of the porous film is preferably 300 s / 100 ml or more. The air permeability of the porous film can be controlled by adjusting the thickness and porosity of the porous film.

  Furthermore, the porosity of the porous film is preferably 30% or more, and more preferably 45% or more, from the viewpoint of ensuring good ion permeability. On the other hand, if the porosity is too large, the strength of the porous film may be insufficient. Therefore, the porosity of the porous film is preferably 80% or less, and more preferably 70% or less. .

  Only one porous film may be fixed on the nonwoven fabric, but two or more porous films may be laminated and fixed on the nonwoven fabric. When laminating a plurality of porous films, the number is preferably 5 or less from the viewpoint of improving the workability. Moreover, it is preferable that the total number of laminated sheets in the separator (total number of nonwoven fabrics and porous films constituting the separator) is 2 to 5.

  Next, a method for manufacturing a laminated nonaqueous secondary battery according to the present invention includes a rectangular non-woven fabric made of a material having a melting point of 200 ° C. or higher and a rectangular porous film made of a material having a melting point of 140 ° C. or lower. An example of using a separator having the following will be described with reference to the drawings. FIG. 4 is a schematic plan view illustrating a situation where the positive electrode sheet is accommodated in the separator. Reference numeral 50 denotes a rectangular nonwoven fabric related to the separator, which is disposed on the upper surface side of the positive electrode sheet, and is fixed to the rectangular nonwoven fabric (not shown) disposed on the lower surface side of the positive electrode sheet at the fixing portion 70. And the rectangular porous film 60 is arrange | positioned on the nonwoven fabric 50, and the porous film 60 and the nonwoven fabric 50 are being fixed by the fixing | fixed part 71 in the edge | side facing the edge | side at the side of the positive electrode tab 31 side. In FIG. 4, the porous film 60 is shown to be transparent in order to facilitate understanding of each component. Reference numeral 80 denotes a heat-resistant tape (for example, a polyimide tape) for fixing the nonwoven fabric 50 to the positive electrode sheet.

  The fixing portion 70 is provided on three sides of the rectangular non-woven fabric 50 (two vertical sides and one side on the positive electrode tab 31 side). Here, the upper non-woven fabric 50 and the lower side of the positive electrode sheet are formed by intermittent welding. The non-woven fabric is fixed. The fixing of the upper nonwoven fabric and the lower nonwoven fabric of the positive electrode sheet may be performed by intermittent welding as shown in FIG. 4, for example, by whole surface welding from one end of the side to the other end. In FIG. 4, as described above, the nonwoven fabric 50 and the porous film 60 are fixed by welding on the side facing the side on the positive electrode tab 31 side. The lower nonwoven fabric is also welded at this location. That is, the configuration shown in FIG. 4 corresponds to an example in which the upper nonwoven fabric 50 and the lower nonwoven fabric of the positive electrode sheet are fixed on four sides. The upper nonwoven fabric 50 and the lower nonwoven fabric of the positive electrode sheet may be fixed on three sides.

  Alternatively, the upper nonwoven fabric and the lower nonwoven fabric of the positive electrode sheet may be a single nonwoven fabric, and one side of the fixed portion 70 may be a folded portion of the single nonwoven fabric. That is, using a non-woven fabric having an area twice or more that of the positive electrode sheet, placing the positive electrode sheet thereon, folding the non-woven fabric so as to wrap the positive electrode sheet, and then removing two or more of the three unfixed sides It may be fixed by welding or the like.

  For example, as shown in FIG. 4, the nonwoven fabric 50 and the porous film 60 may be fixed by whole surface welding from one end to the other end of the side or by intermittent welding.

  In addition, it is preferable that the welding allowance (width | variety of a welding part) shall be 0.5-2 mm. If the welding allowance is too small, workability and reliability may be reduced. On the other hand, when the welding allowance is too large, the size of the laminated electrode body increases, and the energy density per volume of the battery tends to decrease. In addition, when the upper nonwoven fabric 50 and the lower nonwoven fabric of the positive electrode sheet are fixed by intermittent welding, or when the nonwoven fabric 50 and the porous film 60 are fixed by intermittent welding, the welding interval is 2 to 5 mm. It is preferable to do.

  The nonwoven fabric and the porous film constituting the separator are rectangular and include a rectangle (rectangle) and a square, and a suitable shape may be selected according to the shape of the positive electrode sheet and the negative electrode sheet. In addition, the “square” of the nonwoven fabric and the porous film referred to in the present specification includes, for example, a shape in which one or more of the four corners are curved and a shape in which one or more of the four corners are cut off.

  As shown in FIG. 4, the upper nonwoven fabric 50 and the lower nonwoven fabric of the positive electrode sheet are fixed on at least three sides, and the upper nonwoven fabric 50 or the lower nonwoven fabric and the porous film 60 are fixed on one side. Then, as shown in FIG. 5, it is preferable to fix the free end of the porous film 60 to the positive electrode (positive electrode tab 31) with a heat-resistant tape (polyimide tape or the like) 80 or the like.

  The positive electrode sheet and separator integrated product thus obtained and the negative electrode sheet are alternately laminated to obtain a laminated electrode body as shown in FIG. In FIG. 6, in order to facilitate understanding of the arrangement of each component, some components are shown to be transparent. In FIG. 6, 41 is a negative electrode tab. In addition, the laminated | stacked positive electrode sheet, the integrated product of a separator, and the negative electrode sheet fix 1 to 3 places of each side with heat-resistant tapes (polyimide tape etc.) 80. If the number of fixing points on the heat-resistant tape 80 is four or more per side, the permeability of the non-aqueous electrolyte into the electrode is reduced, the time for injecting the non-aqueous electrolyte is increased, and workability is reduced. is there. On the other hand, if the fixing with the heat-resistant tape 80 is not performed, the stacked electrodes are likely to be displaced, and the probability of occurrence of a short circuit may increase.

  A terminal is welded to the laminated electrode body thus obtained as shown in FIG. As the positive electrode terminal 30, for example, an aluminum terminal is preferably used, and as the negative electrode terminal 40, for example, a nickel-plated copper terminal is preferably used. The positive electrode terminal 30 can be welded to the positive electrode tab, and the negative electrode terminal 40 can be welded to the negative electrode tab by ultrasonic welding or the like. Further, the welded portion (both surfaces) of the positive electrode terminal 30 and the welded portion (both surfaces) of the negative electrode terminal 40 are protected with a heat-resistant tape (polyimide tape or the like) 80. In FIG. 7, the heat-resistant tape 80 is hatched and represented as transparent, but this is for the purpose of facilitating understanding of the existence of the heat-resistant tape 80 and the structure below it. The cross section of the heat-resistant tape 80 is not shown.

  The laminated electrode body in which the positive electrode terminal and the negative electrode terminal are welded is accommodated in a laminate film outer package together with the nonaqueous electrolyte, and the outer package is sealed to obtain a laminated nonaqueous secondary battery.

  In the case of a laminate type battery using a laminate film exterior material like the battery of the present invention, a safety device such as a safety valve, a shut-off vent, a cleavage vent, etc., which is adopted in a normal cylindrical battery, is installed in a battery container. It is difficult to provide. However, a laminate type in which a separator having a rectangular non-woven fabric composed of a material having a melting point of 200 ° C. or higher and a rectangular porous film composed of a material having a melting point of 140 ° C. or lower is arranged and used as described above. If it is a non-aqueous secondary battery, even if it does not provide a safety device in the battery container, thermal runaway of the battery can be suppressed and its safety can be ensured.

  Note that the laminated nonaqueous secondary battery shown in FIGS. 4 to 7 is merely a preferred example of the present invention. For example, as described above, the laminated nonaqueous secondary battery of the present invention is A conventionally known separator can also be used. 4 to 7 are shown only for the purpose of facilitating understanding of the configuration of the laminated nonaqueous secondary battery, and the size of each component is not necessarily accurate.

  The laminate type non-aqueous secondary battery of the present invention has good reliability, long life, and high energy density. Therefore, taking advantage of these characteristics, a hybrid vehicle, an electrically assisted bicycle, an electric vehicle, In addition to power applications for devices that require large-capacity batteries such as electric bikes, electric chairs, household and commercial power storage systems, and road leveling, portable electronic devices such as mobile phones and notebook personal computers It can be used for various applications such as a power source where a non-aqueous secondary battery is used.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention.

Example 1
<Preparation of positive electrode sheet>
Lithium cobaltate, carbonaceous conductive aid, and polyvinylidene fluoride (PVDF) are mixed and dispersed in N-methyl-2-pyrrolidone (NMP) at a mass ratio of 90: 5: 5 and stirred to positive electrode A mixture-containing slurry was obtained. The amount of NMP added was adjusted so that the slurry had an appropriate viscosity. This positive electrode mixture-containing slurry was applied to both surfaces of an aluminum foil having a thickness of 15 μm serving as a positive electrode current collector so that the uncoated portions coincided with each other, dried, and then roll-pressed. Then, it cut out into the rectangle in the shape which makes an uncoated part a terminal lead part, and obtained the positive electrode sheet.

<Preparation of negative electrode sheet>
Mesocarbon microbeads and PVDF were mixed and dispersed in NMP at a mass ratio of 95: 5 and stirred to obtain a negative electrode mixture-containing slurry. The amount of NMP added was adjusted so that the slurry had an appropriate viscosity. This negative electrode mixture-containing slurry was applied on both sides of a copper foil having a thickness of 8 μm serving as a negative electrode current collector so that the uncoated portions coincided with each other, dried, and then roll-pressed. Then, it cut out into the rectangle in the shape which makes an uncoated part a terminal lead part, and obtained the negative electrode sheet. The negative electrode sheet was cut into a size larger by 2 mm in length and width than the positive electrode sheet.

<Production of laminated electrode body>
A rectangular non-woven fabric made of polyarylate (melting point: 250 ° C.) having an air permeability of 7 s / 100 ml, a thickness of 25 μm, and a porosity of 70% is arranged above and below the positive electrode sheet, as shown in FIG. The three sides excluding the side facing the side on the positive electrode tab 31 side were intermittently welded at intervals of 2 mm. The welding allowance at that time was 1 mm. Thereafter, the nonwoven fabric 50 and the positive electrode tab 31 portion were fixed with a polyimide tape 80. A rectangular copolymer polypropylene (melting point: 140 ° C.) porous film having an air permeability of 500 s / 100 ml, a thickness of 25 μm, and a porosity of 54% is disposed on the non-woven fabric 50, as shown in FIG. In this way, the porous film 60 and the nonwoven fabric 50 were entirely welded with a welding allowance of 1 mm on the side facing the side on the positive electrode tab 31 side. At this time, simultaneously with the welding of the porous film 60 and the nonwoven fabric 50, the nonwoven fabric 50 and the nonwoven fabric under the positive electrode sheet were also welded. That is, the upper nonwoven fabric 50 and the lower nonwoven fabric of the positive electrode sheet are welded on four sides. Then, as shown in FIG. 5, the free end of the porous film 60 was fixed to the positive electrode tab 31 portion using a polyimide tape 80 (2 mm × 3 mm). In the integrated product of the positive electrode sheet and the separator thus obtained, p: 3 mm and q: 1 mm in FIGS. 4 and 5.

  Fourteen integrated sheets of the above positive electrode sheet and separator were prepared, and alternately stacked with 15 negative electrode sheets to produce a laminated electrode body as shown in FIG. In this laminated electrode body, the negative electrode sheets are both outermost layers. For fixing the positive electrode sheet and separator constituting the laminated electrode body and the negative electrode sheet, a 10 mm × 15 mm polyimide tape 80 was used, and as shown in FIG. One side was fixed on each side. In the laminated electrode body obtained, r: 10 mm, s: 5 mm, t: 67 mm, u: 30 mm, v: 30 mm, w: 60 ± 2 mm, x: 121 mm in FIG.

  Next, as shown in FIG. 7, an aluminum positive electrode terminal 30 having a width of 15 mm and a thickness of 0.2 mm is provided on the positive electrode tab of the above laminated electrode body, and a nickel plating having a width of 15 mm and a thickness of 0.2 mm is provided on the negative electrode tab. The negative electrode terminals 40 made of copper were welded by ultrasonic welding, and a 15 mm × 25 mm polyimide tape 80 was attached to each welded portion for protection. In the laminated electrode body after the positive electrode terminal 30 and the negative electrode terminal 40 are attached, y in FIG. 7 is 143 ± 0.5 mm.

<Assembly of laminated non-aqueous secondary battery>
As the outer package of the laminate-type non-aqueous secondary battery, a laminate film outer package having a cylindrical shape and having no exposed portion of the sealing resin in its body portion was used.

  The laminate film outer package is manufactured using a laminate film in which a nylon sheet (nylon layer) 13 having a thickness of 25 μm, an aluminum sheet 11 having a thickness of 40 μm, and a polypropylene sheet (polypropylene layer) 12 having a thickness of 80 μm are sequentially laminated. did. As shown in FIG. 8, both end portions 15 and 16 serving as joint portions for making the laminate film into a cylindrical shape are obliquely cut at an angle of about 40 ° with respect to the surface, and the nylon layer 13 is placed outside. Thus, the both end portions 15 and 16 were joined together by thermocompression bonding at 210 ° C. to obtain a cylindrical laminated film outer package having no exposed portion of polypropylene as a sealing resin in the body portion.

Said laminated electrode body was accommodated in said laminated film exterior body, and the edge | side by the side of the terminals 30 and 40 was welded and sealed by the welding allowance 10mm. Next, a non-aqueous electrolyte is injected from the remaining one side that is not sealed, the welding margin is set to 10 mm, and the remaining one side is vacuum-sealed by thermal welding. The next battery was obtained. In FIG. 1, a: 70 ± 1 mm, b: 15 mm, c: 25 mm, d: 10 mm, e: 143 ± 1 mm, f: 158 mm, g: 5 ± 0.1 mm. For the non-aqueous electrolyte, LiPF ₆ was dissolved at a concentration of 1 mol / l in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a ratio of 50:50 (mass ratio), and 2% by mass of biphenyl as an aromatic compound was dissolved. In addition, 0.5% by mass of vinylene carbonate, 5% by mass of phoslite, which is a phosphazene compound, and 2% by mass of alicyclic epoxy acryl, which is a gelling agent, were used.

  The laminated nonaqueous secondary battery was stored at 70 ° C. for 15 hours, and the gelling agent was polymerized to form a nonaqueous electrolyte in a gel form. Then, after cooling to room temperature, as a chemical conversion step, the battery was fully charged with a constant current of 0.8 A (0.2 C) and a constant voltage of 4.2 V, and then discharged to 3 V with a constant current of 0.8 A.

Example 2
A laminated nonaqueous secondary battery having the structure shown in FIG. 3 was produced in the same manner as in Example 1 except that a laminate film outer package of the type in which three sides were welded and sealed was used. In addition, the layer structure of the laminate film which concerns on the used laminate film exterior body is the same as the laminate film which concerns on the laminate film exterior body used in Example 1. FIG. The battery of Example 2 is shown in FIG. 3 as h: 90 ± 1 mm, i: 15 mm, j: 25 mm, k: 10 mm, l: 143 ± 1 mm, m: 158 mm, n: 10 mm, o: 5 ± 0.1 mm. .

Example 3
A laminated nonaqueous secondary battery was fabricated in the same manner as in Example 2 except that a laminated electrode body was prepared using 7 separators and 7 positive electrode sheets and 8 negative electrode sheets, and this laminated electrode body was used. Produced. The battery of Example 3 is o: 2.6 + 0.1 mm in FIG. 3, and other sizes are the same as those of Example 2.

Example 4
A laminated non-aqueous secondary battery was prepared in the same manner as in Example 2 except that a laminated electrode body was prepared using 4 separators and 4 positive electrode sheets and 5 negative electrode sheets, and this laminated electrode body was used. Produced. The battery of Example 4 is o: 1.6 + 0.1 mm in FIG. 3, and other sizes are the same as those of Example 2.

Comparative Example 1
A laminated nonaqueous secondary battery was prepared in the same manner as in Example 2 except that a laminated electrode body was prepared using two integrated separators and positive electrode sheets and three negative electrode sheets, and this laminated electrode body was used. Produced. The battery of Comparative Example 1 is o: 1.0 + 0.1 mm in FIG. 3, and other sizes are the same as those of Example 2.

Comparative Example 2
A laminated nonaqueous secondary battery was prepared in the same manner as in Example 2 except that a laminated electrode body was prepared using one separator and positive electrode sheet and two negative electrode sheets, and this laminated electrode body was used. Produced. The battery of Comparative Example 2 is o: 0.6 + 0.1 mm in FIG. 3, and other sizes are the same as those of Example 2.

For the batteries of Examples 1 to 4 and Comparative Examples 1 and 2, the battery capacity (initial capacity) was measured by the following method, and the output density was calculated using the initial capacity. These results are shown in Table 1 together with the ratio A / C between the area A (cm ² ) of the sealing resin exposed outside the battery and the battery capacity C (mAh).

  About the battery of Examples 1-4 and Comparative Examples 1-2, the constant current charge which charges to 4.2V by 0.2C (0.8A) and the constant voltage charge by 4.2V are performed (constant current charge and The total charging time with constant voltage charging: 6.5 hours), discharging at 0.2 C to 3 V to determine the discharge capacity, and this discharge capacity was taken as the initial capacity. The output density was calculated by multiplying the above initial capacity (Ah) by the average voltage (3.8 V) during battery operation to calculate the output (Wh), and further dividing this output by the volume (L) of the battery. .

  Moreover, about the battery of Examples 1-4 and Comparative Examples 1-2, the battery capacity maintenance rate and the direct current | flow resistance (DCR) increase rate were measured as a battery life characteristic. The battery capacity maintenance rate and the DCR increase rate are constant current charging and charging at 4.2 V with the batteries of Examples 1 to 4 and Comparative Examples 1 and 2 up to 4.2 V at 0.2 C (0.8 A). After constant voltage charging (total charging time of constant current charging and constant voltage charging: 6.5 hours), stored for a predetermined number of days at 50 ° C., and then discharged capacity to 3 V at 0.2 C and The DCR was determined, and the capacity retention rate (%) and DCR increase rate (%) after storage for a predetermined number of days were determined from the discharge capacity in the initial state (before storage) and the ratio with DCR. The result of the capacity maintenance rate is shown in FIG. 9, and the result of the DCR increase rate is shown in FIG.

  The batteries of Examples 1 to 4 have a higher capacity retention rate after storage days and a lower DCR increase rate than the batteries of Comparative Examples 1 and 2, and have excellent life characteristics and reliability. ing. As can be seen from Table 1, the batteries of Examples 1 to 4 are superior to the batteries of Comparative Examples 1 and 2 in terms of output density (energy density).

It is a schematic diagram which shows an example of the 1st aspect of the lamination type non-aqueous secondary battery of this invention. It is a partially expanded view of the side surface of FIG. It is a schematic diagram which shows an example of the 2nd aspect of the laminate type non-aqueous secondary battery of this invention. It is a plane schematic diagram which shows the condition which accommodated the positive electrode sheet in the suitable example of the laminate-type non-aqueous secondary battery of this invention in the separator. It is a plane schematic diagram which shows the condition which accommodated the positive electrode sheet in the suitable example of the laminate-type non-aqueous secondary battery of this invention in the separator. It is a plane schematic diagram which shows the structure of the laminated electrode body in the suitable example of the lamination type non-aqueous secondary battery of this invention. It is a plane schematic diagram which shows the structure of the laminated electrode body in the suitable example of the lamination type non-aqueous secondary battery of this invention. FIG. 3 is a schematic cross-sectional view for explaining the method for manufacturing the laminated film exterior body of Example 1. It is a graph which shows the result of the capacity | capacitance maintenance factor with respect to the storage days of the lamination type non-aqueous secondary battery of an Example and a comparative example. It is a graph which shows the result of the direct current | flow resistance increase rate with respect to the storage days of the lamination type non-aqueous secondary battery of an Example and a comparative example.

Explanation of symbols

10, 14 Laminate film outer package 20 Sealing portion 30 Positive electrode terminal 40 Negative electrode terminal

Claims (6)

A laminated electrode body in which a positive electrode sheet in which a positive electrode active material-containing layer is formed on a positive electrode current collector and a negative electrode sheet in which a negative electrode active material-containing layer is formed on a negative electrode current collector are laminated via a separator , And a non-aqueous electrolyte are accommodated in a cylindrical laminate film exterior body in which an upper end and a lower end are welded and sealed ,
The separator has a rectangular non-woven fabric composed of a material having a melting point of 200 ° C. or higher, and a rectangular porous film composed of a material having a melting point of 140 ° C. or lower,
The rectangular nonwoven fabric in the separator is disposed on both surfaces of the positive electrode sheet, and the lower nonwoven fabric and the upper nonwoven fabric of the positive electrode sheet are fixed on at least three sides,
At least one of the square of the nonwoven fabric disposed on both sides of the positive electrode sheet, a porous film of the square of the separator, lamination type non-aqueous secondary battery comprising that you have been fixed at its one side. The laminated non-aqueous secondary battery according to claim 1 , wherein the lower nonwoven fabric and the upper nonwoven fabric of the positive electrode sheet are fixed by intermittent welding or whole surface welding. The laminated nonaqueous secondary battery according to claim 1 or 2 , wherein the nonwoven fabric and the porous film in the separator are fixed by intermittent welding or whole surface welding. The laminated nonaqueous secondary battery according to any one of claims 1 to 3 , wherein the nonwoven fabric in the separator is made of at least one material selected from the group consisting of polyarylate, polyethylene terephthalate, and polybutylene terephthalate. The laminated nonaqueous secondary battery according to any one of claims 1 to 4 , wherein the nonwoven fabric in the separator has an air permeability of 300 s / 100 ml or less, a porosity of 30 to 80%, and a thickness of 5 to 50 µm. The porous film of the separator, air permeability 600s / 100 ml or less, a porosity of 30% to 80%, the laminate-type nonaqueous secondary battery according to any one of claims 1 to 5, a thickness of 5~50μm .

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