JP4830295B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery excellent in safety and reliability when pressure is applied from the outside.

  In recent years, smaller and lighter batteries have been demanded as power sources for mobile communication devices and portable electronic devices, and non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries have become mainstream.

  This battery uses a positive electrode and a negative electrode in which an electrode mixture layer composed of an active material, a conductive material, and a binder is formed on a metal foil. The positive electrode plate and the negative electrode plate are made of polyolefin resin fine particles. The electrode plate group wound in an insulated state through a porous membrane separator and a non-aqueous electrolyte using a lithium salt as an electrolyte are housed in a battery case.

  At present, in order to meet the demand for higher capacity of batteries, positive electrode active materials such as lithium nickelate, and negative electrode materials represented by nitrides and alloys are being developed. Has been made.

  On the other hand, current collectors and lead terminals that do not contribute to battery capacity, plate thickness of battery cases, thinning of separators, etc. and increased packing density of electrodes, the amount of substantial active material in limited battery cases As the current collector becomes thinner, the sharpness deteriorates, and when the cutting burr occurs or the separator becomes thinner, the distance between the positive electrode and the negative electrode becomes shorter. Since it becomes easy to short-circuit, the proposal which ensures safety | security is made (for example, refer patent document 1, 2).

However, when the thickness of the separator is reduced, the electrode plate or battery facing the separator through the burr at the end of the electrode plate made of a current collector without an electrode mixture layer, which has not been a problem in the past, or the battery An internal short circuit with the case may occur.
JP 2001-035537 A JP 2004-259625 A

  The present invention provides a high-capacity non-aqueous electrolyte secondary battery that includes the electrode plate group in which the above-described problems are solved and a positive electrode plate and a negative electrode plate are wound in an oval shape via a separator. Even when external pressure is applied to the battery, the electrode current collector and electrode mixture layer do not cause a short circuit or internal short circuit. An object is to provide a battery.

In order to solve the above problems, the non-aqueous electrolyte secondary battery of the present invention comprises an ellipse with each electrode mixture and a positive electrode plate and a negative electrode plate made of a current collector supporting the electrode mixture interposed between separators. An electrode plate group wound in a shape, wherein the electrode plate group is a region where the outermost electrode mixture terminal portion of the negative electrode plate and the current collector without the outermost electrode mixture layer of the positive electrode plate face each other And the current collector without the outermost peripheral electrode layer of the positive electrode plate has an electrode plate group longer than the terminal portion of the current collector without the outermost peripheral electrode layer of the negative electrode plate. collector with no layer positive electrode plate is coated with an insulating member, said insulating member, characterized in that is opposed to the electrode mixture layer and the current collector end portion of the negative electrode plate via a separator, The insulating member is an insulating tape made of a base material and a paste, and the thickness of the base material is 10 μm or more and the positive electrode plate Is preferably smaller than the thickness of the electrode mixture layer, the size of the substrate is longer than the width of the positive electrode plate, and is preferably shorter than the width of the separator.

  In addition, it is preferable to use one kind selected from polypropylene resin, polyphenylene sulfite resin, and polyimide resin as the material of the base material of the insulating tape, and a paste is applied to a portion longer than the width of the positive electrode plate of the insulating tape. However, it is preferable to use a tape on which a paste is applied to a part or all of the portion facing the width of the positive electrode plate.

  The lithium secondary battery of the present invention is a high-capacity non-aqueous electrolyte secondary battery having an electrode plate group in which a positive electrode plate and a negative electrode plate are wound in an oval shape with a separator interposed therebetween. Even when pressure is applied from the outside, it is possible to provide a non-aqueous electrolyte secondary battery that is highly safe and highly reliable.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a rectangular nonaqueous electrolyte secondary battery, and FIG. 2 is a detailed view of the outermost peripheral portion of the electrode plate group.

  An electrode plate group in which the positive electrode plate 11 and the negative electrode plate 13 are insulated via a separator 15 is accommodated in a bottomed battery case 18 having an open top.

  The negative electrode lead 14 connected to the negative electrode plate 13 is electrically connected to the internal terminal 20 of the sealing plate 19 having the safety valve 24 via the upper insulating plate 16, and the rivet 25 also serving as the negative electrode external connection terminal is connected to the sealing plate 19. An upper insulating gasket 21 and a lower insulating gasket 22 are arranged between them, and are caulked together with the internal terminal 20 to obtain electrical conduction and sealing. A positive electrode lead 12 connected to the positive electrode plate 11 is electrically connected to a sealing plate 19 via an upper insulating plate 16.

  The lower end portion of the electrode group and the battery case 18 are insulated by the lower insulating plate 17, and the upper insulating plate 16 insulates the negative electrode lead 14, the battery case 18, the electrode group, and the sealing plate 19 having a current blocking mechanism. ing. The sealing plate 19 is fitted to the battery case 18, and the fitting portion is hermetically sealed by laser welding. Then, a sealing structure in which a predetermined amount of electrolyte is injected from the liquid injection hole of the sealing plate and the liquid injection hole is sealed and sealed by laser welding to the sealing plate 19 with the plug 23.

  The positive electrode plate 11 is formed by, for example, applying a positive electrode paste to one or both sides of a positive electrode current collector having a thickness of 10 μm to 60 μm that has been processed or etched with aluminum or an aluminum alloy foil, dried, and rolled. Then, a positive electrode active material layer is formed. The positive electrode paste is prepared by dispersing a positive electrode active material, a binder, a conductive agent, and, if necessary, a thickener in a dispersion medium.

Although it does not specifically limit as a positive electrode active material, For example, the lithium containing transition metal compound which can accept a lithium ion as a guest is used. For example, a composite metal oxide of at least one transition metal selected from cobalt, manganese, nickel, chromium, iron and vanadium and lithium is used. Among these, Li _x CoO ₂ , Li _x MnO ₂ , Li _x NiO ₂ , LiCrO ₂ , αLiFeO ₂ , LiVO ₂ , Li _x Co _y Ni _1-y O ₂ , Li _x Co _y M _1-y O _z , Li _{x Ni 1-y M y O z} , Li x Mn 2 O 4, Li x Mn 2-y M y O 4 ( here,
M = Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb and B, at least one selected from x = 0 to 1.2, y = 0.9 to 0.9, z = 2.0 to 2.3), transition metal chalcogenides, lithiated vanadium oxides, lithiated niobium oxides, and the like. These may be used alone or in combination of two or more. In addition, said x value increases / decreases by charging / discharging. The average particle diameter of the positive electrode active material is preferably 1 μm to 30 μm.

  The binder, conductive agent, and thickener that can be added as necessary can be the same as those used in the past.

  The binder is not particularly limited as long as it can be dissolved or dispersed in a paste dispersion medium. For example, a fluorine-based binder, acrylic rubber, modified acrylic rubber, styrene-butadiene rubber (SBR). An acrylic polymer, a vinyl polymer, or the like can be used. These may be used alone or in combination of two or more. As the fluorine-based binder, for example, polyvinylidene fluoride, a copolymer of vinylidene fluoride and propylene hexafluoride, polytetrafluoroethylene, and the like are preferable, and these can be used as a dispersion.

  As the conductive agent, acetylene black, graphite, carbon fiber, or the like can be used. These may be used alone or in combination of two or more.

  As the thickener, ethylene-vinyl alcohol copolymer, carboxymethyl cellulose, methyl cellulose and the like are preferable.

  A suitable dispersion medium is one in which the binder can be dissolved. When using an organic binder, N-methyl-2-pyrrolidone, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide, dimethyl sulfoxide, hexamethylsulfuramide, tetramethylurea, acetone, methyl ethyl ketone, etc. alone or It is preferable to use a mixture. Moreover, when using a water-system binder, water and warm water are preferable.

  A method for producing a positive electrode paste by dispersing a positive electrode active material, a binder, a conductive agent, and a thickener added as necessary in a dispersion medium is not particularly limited. A mixer, a pin mixer, a kneader, a homogenizer, or the like can be used. These may be used alone or in combination of two or more. In addition, various dispersants, surfactants, stabilizers, and the like can be added as necessary when the positive electrode paste is kneaded and dispersed.

  The positive electrode paste can be easily applied to the positive electrode current collector using, for example, a slit die coater, reverse roll coater, lip coater, blade coater, knife coater, gravure coater, dip coater, or the like. The positive electrode paste applied to the positive electrode current collector is preferably dried close to natural drying, but considering productivity, it is preferably dried at a temperature of 70 ° C. to 200 ° C. for 10 minutes to 5 hours.

  Rolling is preferably performed several times at a linear pressure of 1000 to 2000 kg / cm or by changing the linear pressure until the positive electrode plate has a predetermined thickness of 130 μm to 200 μm by a roll press.

  The negative electrode plate 13 is formed by applying a negative electrode paste to one or both sides of a negative electrode current collector having a thickness of 10 μm to 50 μm made of, for example, ordinary copper foil or lath-processed or etched copper foil, dried, and rolled. It is produced by forming a negative electrode active material layer. The negative electrode paste is prepared by dispersing a negative electrode active material, a binder, and optionally a conductive agent and a thickener in a dispersion medium. The negative electrode is provided with a plain portion having no active material layer, and the negative electrode lead 14 is welded thereto.

  Although it does not specifically limit as a negative electrode active material, It is preferable to use the carbon material which can discharge | release and occlude lithium ion by charge / discharge. For example, carbon materials obtained by firing organic polymer compounds (phenolic resin, polyacrylonitrile, cellulose, etc.), carbon materials obtained by firing coke and pitch, artificial graphite, natural graphite, pitch-based carbon fibers, A PAN-based carbon fiber or the like is preferable, and the shape thereof can be a fibrous shape, a spherical shape, a scale shape, or a lump shape.

  As the binder, the conductive agent used as necessary, and the thickener, the same ones as in the past can be used. For example, the same binder, conductive agent, and thickener as those for the positive electrode plate can be used.

  The material of the separator 15 is polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene from the viewpoints of heat resistance, organic solvent resistance and hydrophobicity, and a shutdown function. , Polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyether (polyethylene oxide or polypropylene oxide), cellulose (carboxymethylcellulose or hydroxypropylcellulose), poly (meth) acrylic acid, poly (meth) acrylic acid ester, etc. A microporous film made of molecules is preferably used. A multilayer film in which these microporous films are superposed is also used. Among these, a microporous film made of polyethylene, polypropylene, polyvinylidene fluoride, or the like is suitable, and the thickness is preferably 15 μm to 30 μm.

  An electrode group in which the positive electrode plate 11 and the negative electrode plate 13 thus obtained are wound in a flat shape via the separator 15 is used to produce an oval electrode plate group by pressing from the long side surface. .

  In the outermost peripheral part of the electrode plate group, there is a region where the outermost peripheral electrode mixture terminal portion 13b of the negative electrode plate 13 and the current collector 11a without the outermost peripheral electrode mixture layer of the positive electrode plate 11 face each other. In addition, the positive electrode plate 11 is configured such that the current collector 11a without the outermost peripheral electrode layer of the positive electrode plate 11 is longer than the terminal portion 13a of the current collector without the outermost peripheral electrode layer of the negative electrode plate 13, and without the electrode mixture layer. A plate current collector 11 a is covered with an insulating member 31, and is opposed to the electrode mixture layer terminal portion 13 b and the current collector terminal portion 13 a of the negative electrode plate 13 with a separator 15 interposed therebetween.

  With such a configuration, it is possible to prevent an internal short circuit with the positive electrode plate 11 due to burrs of the electrode mixture layer terminal portion 13b and the current collector terminal portion 13a.

  The insulating member used in the present invention is an insulating tape composed of a base material and a paste, and is required to have high heat resistance and not to be dissolved or swelled in a non-aqueous electrolyte, and as a material thereof, polypropylene resin, polyphenylene sulfite It is preferable to use one selected from a resin and a polyimide resin. Examples of the paste include natural rubber, isobutyl rubber, styrene butadiene rubber, silicon rubber, urethane rubber, and acrylic resin. These can be used alone, laminated or modified.

The thickness of the base material of the insulating tape needs to be thicker than the current collector burrs of the positive electrode plate, and is preferably 10 μm or more. In addition, if the thickness of the base material of the insulating tape is too thick, a gap is generated between the electrode plate and the separator at the portion where the tape is applied, and the electrode plate group is likely to swell. Is preferably 50 μm or less.

  By using a tape on which a part of the insulating tape is longer than the width of the positive electrode plate and no adhesive is applied, and a part of or all of the part facing the width of the positive electrode plate is attached with the adhesive, And the positive electrode plate to which the tape is attached does not adhere to a roller or the like that passes by the time of winding, so that the electrode mixture layer does not peel from the current collector, A battery having better internal short circuit resistance can be obtained.

  As the material of the battery case 18, copper, nickel, stainless steel, nickel-plated steel or the like can be used, and these materials can be subjected to drawing processing, DI processing, etc. to form the shape of the battery case 18, but aluminum or aluminum By using a battery case made of an alloy, a square sealed secondary battery having a light weight and a high energy density can be easily manufactured.

  The non-aqueous electrolyte is composed of a non-aqueous solvent and a solute, and the non-aqueous solvent contains a cyclic carbonate and a chain carbonate as main components. The cyclic carbonate is preferably at least one selected from ethylene carbonate (EC), propylene carbonate (PC), γ-butyllactone (γBL) and butylene carbonate (BC). The chain carbonate is preferably at least one selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and the like.

As the solute, for example, a lithium salt having a strong electron withdrawing property is used, for example, LiPF ₆ ,
Examples include LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) _{3 and the} like. These electrolytes may be used alone or in combination of two or more. These solutes are preferably dissolved at a concentration of 0.5 to 1.5 M in the non-aqueous solvent.

  Hereinafter, although it demonstrates in detail using an Example and a comparative example, these do not limit this invention at all.

Example 1
In the positive electrode plate 11, carbon black as a conductive agent is added to LiCoO ₂ which is a positive electrode active material, and polytetrafluoroethylene aqueous dispersion is used as a binder in a mass ratio of 100: 3: 10 in a solid content ratio. The kneaded and dispersed paste is coated on a current collector made of aluminum foil with a thickness of 30 μm on both sides by a doctor blade method to a thickness of about 230 μm, dried, rolled to a thickness of 180 μm, and cut to a predetermined size. The positive electrode lead 12 made from aluminum was welded.

  The outermost peripheral electrode mixture terminal portion 13b of the negative electrode plate 13 and the current collector 11a without the outermost peripheral electrode mixture layer 11b of the positive electrode plate 11 are opposed to each other, and the positive electrode plate 11 The current collector 11a without the outermost peripheral electrode layer 11b is configured to be longer than the terminal portion of the current collector 13a without the outermost peripheral electrode layer 13b of the negative electrode plate 13, and the current collector 11a of the positive electrode plate is A base material having a thickness of 20 μm made of a polypropylene resin film, covered with an insulating member 31 made of an insulating tape having the same dimensions as the width of the positive electrode plate 11, and the electrode mixture layer 13 b of the negative electrode plate 13 through the separator 15 and It arrange | positioned so that the electrical power collector termination | terminus part 13a might be opposed.

  The negative electrode plate 13 is a collection of copper foil having a thickness of 20 μm made of a carbonaceous material as a main material and a paste obtained by kneading and dispersing a styrene butadiene rubber binder in a mass ratio of 100: 5. A double-sided coating is applied to a thickness of about 230 μm on an electric body by a doctor blade method, dried, rolled to a thickness of 180 μm, cut to a predetermined size, and a nickel-made negative electrode lead 14 is welded thereto. The one having a 30 μm burr at the time of cutting was used.

  The three-layer separator 15 in which the positive electrode plate 11 and the negative electrode plate 13 thus produced are arranged with a microporous separator made of polypropylene resin having a thickness of 5 μm on both sides of a microporous separator made of polyethylene resin having a thickness of 10 μm. A rectangular battery case with a bottom that is made of an aluminum alloy and has an open top made by pressing a flat wound electrode group from the long side surface to produce an elliptical electrode plate group 18 was stored.

  A nickel negative electrode lead 14 connected to the negative electrode plate 13 is made of an aluminum alloy having a safety valve 24 via an upper insulating plate 16 and is electrically connected to an internal terminal 20 of a sealing plate 19 having a thickness of 1 mm. The rivet 25 that also serves as a connection terminal is provided with an upper insulating gasket 21 having a thickness of 0.500 mm and a lower insulating gasket 22 having a thickness of 0.185 mm between the sealing plate 19 and the compression ratio of 20%. By caulking together with the internal terminal 20, electrical connection is obtained and sealing is performed. The aluminum positive electrode lead 12 connected to the positive electrode plate 11 was electrically connected to the sealing plate 19 via the upper insulating plate 16.

The lower end portion of the electrode group and the battery case 18 are insulated by the lower insulating plate 17, and the upper insulating plate 16 insulates the negative electrode lead 14, the battery case 18, the electrode group, and the sealing plate 19 having a current blocking mechanism. ing. The sealing plate 19 is fitted to the battery case 18, and the fitting portion is hermetically sealed by laser welding. Thereafter, a predetermined amount of non-aqueous electrolyte was injected from the injection hole of the sealing plate. As the non-aqueous non-aqueous liquid, a solution obtained by dissolving LiPF ₆ at a concentration of 1.0 mol / l in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 1: 3 was used. In addition, what added 1 mass part cyclohexylbenzene as an additive for overcharge resistance was used per 100 mass parts of nonaqueous solvents.

  Finally, the liquid injection hole is sealed and sealed by laser welding to the sealing plate 19 with the sealing plug 23, and the outer dimensions of the thickness, width and height are 5.3 mm, 30 mm and 48 mm, respectively, and the battery capacity is An 800 mAh square sealed lithium ion secondary battery was fabricated and used as the battery of Example 1.

(Examples 2-3)
As the base material of the insulating member 31 that covers the current collector 11a without the outermost peripheral electrode mixture layer 11b of the positive electrode plate 11, except that a 20 μm thick polyphenylene sulfite resin or a polyimide resin film was used, A square sealed lithium ion secondary battery was produced in the same manner as in Example 1, and the batteries of Example 2 and Example 3 were obtained, respectively.

(Comparative Example 1)
A square sealed lithium ion secondary battery was produced in the same manner as in Example 1 except that the current collector 11a without the outermost peripheral electrode mixture layer 11b of the positive electrode plate 11 was not coated. It was.

  Using each of the five batteries of Examples 1 to 3 and Comparative Example 1 thus obtained, an internal short circuit test 1 was conducted, and the results are shown in Table 1.

  The internal short circuit test 1 is performed when the press pressure is increased to 8000 N while applying an applied voltage of 5.0 V from the long side surface of the square sealed lithium ion secondary battery, and the internal short circuit and the internal short circuit are detected. The press pressure at that time was examined.

  From Table 1, even if it is the electrode mixture layer 13b of the negative electrode plate 13 and the current collector terminal portion 13a having burrs at the time of cutting, the current collector 11a without the outermost peripheral electrode mixture layer 11b of the opposing positive electrode plate 11 It was clarified that the internal short circuit does not occur even when the press pressure is increased to 8000 N by covering the film with the insulating member 31.

(Example 4 to Example 9)
Instead of having a burr at the time of cutting the negative electrode plate, a negative electrode plate in which 10 particles of stainless steel (SUS) needle-like or aluminum core material abrasive powder as metal foreign matter are attached on the current collector terminal portion 13a of the negative electrode plate 13, A square sealed lithium ion secondary battery was produced in the same manner as in Example 1 except that a polypropylene resin film having a thickness of 20 μm was used as the base material of the insulating member 31, and Example 4 and Example respectively. 5 batteries were obtained.

  Similarly, a square sealed lithium ion secondary battery was prepared in the same manner as in Examples 4 and 5 except that a film made of polyphenylene sulfite resin or polyimide resin was used as the base material of the insulating member 31. The batteries of Examples 6 to 9 were produced.

(Comparative Example 2 to Comparative Example 3)
A square sealed lithium ion secondary battery was fabricated and compared in the same manner as in Examples 4 and 5 except that the current collector 11a without the outermost peripheral electrode mixture layer 11b of the positive electrode plate 11 was not coated. The batteries of Example 2 and Comparative Example 3 were obtained.

  The internal short-circuit test 2 was performed using each of the five batteries of Examples 4 to 9, Comparative Example 2, and Comparative Example 3 obtained in this manner, and the results are shown in Table 2.

  The internal short circuit test 2 is performed when the press pressure is increased to 8000 N while applying a voltage of 5.0 V from the long side surface of the square sealed lithium ion secondary battery, and when there is an internal short circuit and when the internal short circuit occurs. When an internal short circuit did not occur, the applied voltage was increased to 1 KV with the press pressure at 8000 N, and the presence or absence of an internal short circuit and the applied voltage at that time were examined.

  From Table 2, even if it is the electrode mixture layer 13b of the negative electrode plate 13 and the current collector terminal portion 13a to which the metal foreign matter is adhered, the current collector 11a without the outermost electrode mixture layer 11b of the opposing positive electrode plate 11 is present. In the case of Comparative Example 2 and Comparative Example 3, all of the press pressures were internally short-circuited in the range of 216N to 7750N, but even if the press pressure was increased to 8000N, internal short-circuiting was performed. However, when the applied voltage was increased to 1 KV, one of five internal short circuits occurred regardless of the type of substrate.

  This is presumably because an internal short circuit occurred in the gap and the upper and lower end surfaces due to harassment during sticking because the insulating member 31 made of an insulating tape having the same dimensions as the width of the positive electrode plate 11 was used.

(Example 10 to Example 13)
A polypropylene resin film with a thickness of 20 μm is used as the base material of the insulating member 31 and is longer than the positive electrode width and shorter than the separator width, and an acrylic resin paste is pasted over the entire width. A rectangular sealed lithium ion secondary battery was produced in the same manner as in Example 4 except that the worn one was used, and a battery of Example 10 was obtained.

  Further, Example 10 was used except that the width was longer than the positive electrode width and shorter than the width of the separator, and the positive electrode width was used and an acrylic resin-based paste was attached only to the entire width. Similarly, a square sealed lithium ion secondary battery was produced and used as the battery of Example 11.

  The length of the positive electrode is longer than the width of the separator and shorter than the width of the separator. A rectangular sealed lithium ion secondary battery was produced in the same manner as in Example 10 except that the battery of Example 12 was obtained.

  Furthermore, the corners were the same as in Example 10 except that the length was longer than the width of the positive electrode and longer than the width of the separator, and an acrylic resin paste was applied to the entire width. Type sealed lithium ion secondary battery was fabricated and used as the battery of Example 13.

  Using the five batteries of Examples 10 to 13 obtained in this way, the internal short circuit test 2 was performed, and the results are shown in Table 3.

  From Table 3, even if it is the electrode mixture layer 13b of the negative electrode plate 13, and the collector termination | terminus part 13a to which the metal foreign material was made to adhere, the collector 11a without the outermost peripheral electrode mixture layer 11b of the opposing positive electrode plate 11 As the base material of the insulating member 31 covering the surface, the length of the positive electrode is longer than the width of the separator and shorter than the width of the separator. In the case of Example 11 and Example 12 in which the acrylic resin paste was applied to only a part of the width of the positive electrode, no internal short circuit occurred even when the applied voltage was increased to 1 KV. In the case of Example 10 and Example 13 in which the paste was applied to a portion longer than the length of the positive electrode width, the paste was attached to a roller or the like that passed by the time of winding, and the electrode mixture layer was When it is peeled off from the current collector and the applied voltage is increased to 1 KV, an internal short circuit occurs. There was a thing.

(Examples 14 to 19)
Square sealed lithium as in Example 11 except that a polypropylene resin film was used as the base material of the insulating member 31 and the thickness was 5 μm, 10 μm, 30 μm, 40 μm, 50 μm, or 60 μm. Ion secondary batteries were produced and used as batteries of Example 14, Example 15, Example 16, Example 17, Example 18, and Example 19, respectively.

  A flat plate press limit test was performed using each of the five batteries of Example 10, Example 14 to Example 19, and Comparative Example 2 obtained as described above, and the results are shown in Table 4.

  In the flat plate press limit test, a fully charged battery was charged under a constant current until the battery voltage reached 4.2 V after remaining discharge at a constant current up to a final voltage of 3.0 V in an environment of 20 ° C. A flat plate press was performed at a pressure of 29.5 kN, and the presence or absence of ignition was examined.

  From Table 4, even if it is the electrode mixture layer 13b of the negative electrode plate 13 and the current collector terminal portion 13a to which the metal foreign matter is adhered, the current collector 11a without the outermost peripheral electrode mixture layer 11b of the opposing positive electrode plate 11 is used. It was found that the battery did not ignite when a thickness of 10 μm or more was used as the thickness of the base material of the insulating member 31 covering the metal.

  This is because, by using a material having a thickness of 10 μm or more as the base material of the insulating member 31, it is possible to prevent foreign matters from breaking through the insulating member and causing an internal short circuit, and thus a battery having excellent reliability can be obtained. all right.

  According to the nonaqueous electrolyte secondary battery of the present invention, it is possible to provide a highly reliable and highly reliable nonaqueous electrolyte secondary battery even when pressure is applied from the outside. It is useful as a power source for driving portable electronic devices.

1 is a longitudinal sectional view of a prismatic nonaqueous electrolyte secondary battery according to an embodiment of the present invention. Detailed drawing of the outermost peripheral portion of the electrode plate group according to one embodiment of the present invention

DESCRIPTION OF SYMBOLS 11 Positive electrode plate 11a Current collector of positive electrode plate outermost periphery 11b Electrode mixture termination | terminus part of positive electrode plate outermost periphery 12 Positive electrode lead 13 Negative electrode plate 13a Current collector termination | terminus part of negative electrode plate outermost periphery 13b Electrode mixture termination | terminus of negative electrode plate outermost periphery Part 14 Negative electrode lead 15 Separator 16 Upper insulating plate 17 Lower insulating plate 18 Battery case 19 Sealing plate 20 Internal terminal 21 Upper insulating gasket 22 Lower insulating gasket 23 Seal 24 Safety valve 25 Rivet 31 Insulating member

Claims (5)

Each of the electrode mixtures and a positive electrode plate and a negative electrode plate made of a current collector that support the electrode mixture are provided with an electrode plate group that is wound in an oval shape with a separator interposed between the electrode plate group and the electrode plate group. The current collector without the outermost peripheral electrode layer of the positive electrode plate has a region in which the end portion of the outer peripheral electrode mixture and the current collector without the outermost peripheral electrode mixture layer of the positive electrode plate face each other. In a battery having an electrode plate group longer than the terminal end of the current collector without the outermost peripheral electrode layer of the plate,
The current collector of the positive electrode plate without the electrode mixture layer is covered with an insulating member, and the insulating member is opposed to the electrode mixture layer of the negative electrode plate and the current collector terminal portion via a separator. A non-aqueous electrolyte secondary battery. The insulating member is an insulating tape composed of a base material and a paste, and the thickness of the base material is 10 μm or more and not more than the thickness of the electrode mixture layer of the positive electrode plate. Non-aqueous electrolyte secondary battery. 3. The nonaqueous electrolyte secondary battery according to claim 1, wherein the base material of the insulating tape is one selected from polypropylene resin, polyphenylene sulfite resin, and polyimide resin. 4. . The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein a dimension of the base material of the insulating tape is longer than a width of the positive electrode plate and shorter than a width of the separator. The adhesive tape is not pasted on a portion longer than the width of the positive electrode plate of the insulating tape, and a tape on which a paste is pasted on a part or all of the portion facing the width of the positive electrode plate is used. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4.

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