JP5337418B2 - Non-aqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery capable of restraining a collector from curving and preventing short-circuiting due to biting-in of a mixture non-coated part. <P>SOLUTION: The nonaqueous electrolyte secondary battery is provided with an electrode group with a cathode and an anode plates 1, 5 wound around via a separator. On either side of a cathode collector, a mixture coated part 1A and a mixture non-coated part 1B on one side along a length direction of the collector are formed. On either side of an anode collector, a mixture coated part 5A and a mixture non-coated part 5B are formed. A plurality of open holes 10 are formed on collectors at the mixture non-coated parts 1B, 5B, at parts excluding outside edge parts along a length direction. Each open hole 10 is of an elliptical shape with its long axis formed in a direction crossing a length direction of the collector. At winding around of the cathode and the anode plates 1, 5, the mixture non-coated parts 1B, 5B are wound around in an erected state. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and in particular, an active material mixture is applied to the current collector surface, and an active material mixture is not applied to one side along the longitudinal direction of the current collector. An electrode group in which a positive electrode plate and a negative electrode plate each having a contact portion are wound through a separator, a non-aqueous electrolyte infiltrating the electrode group, and a battery container that accommodates the electrode group and the non-aqueous electrolyte The present invention relates to a non-aqueous electrolyte secondary battery.

  Among non-aqueous electrolyte secondary batteries, lithium secondary batteries are widely used as power sources for portable devices such as VTR cameras, notebook computers, and mobile phones. On the other hand, since lithium secondary batteries have high energy density, they are being developed as in-vehicle power sources for electric vehicles (EV) and hybrid vehicles (HEV), and some of them are put into practical use. In these applications, a single large lithium secondary battery may be used, or a battery system in which a plurality of large lithium secondary batteries are incorporated may be used.

  Usually, a lithium secondary battery has the following wound internal structure. That is, a group of electrodes wound in a spiral shape is formed so that the strip-like positive and negative electrode plates each having the active material mixture coated portion formed on the metal foil as the current collector are not in direct contact with each other through the separator. Has been. When the positive and negative electrode plates are wound, they are wound while applying tension to prevent twisting. This electrode group is infiltrated with a non-aqueous electrolyte solution and accommodated in a battery container and sealed. In lithium secondary batteries that require high input / output characteristics such as EV and HEV power supplies, in order to reduce internal resistance, the active material mixture is not coated on one side along the longitudinal direction of the current collector. And has a structure in which the potential is evenly collected from the uncoated portion to the longitudinal direction of the current collector.

  However, when the applied portion of the active material mixture is pressed in order to improve the volumetric energy density of the secondary battery, as shown in FIG. Arise. On the other hand, since the mixture uncoated portion 30B is not compressed, the current collector does not stretch. For this reason, there is a problem that the current collector of the electrode plate 30 is distorted and curved. In order to solve this problem and reduce the above-described internal resistance, as shown in FIG. 5, the mixture uncoated portion 40B of the electrode plate 40 is cut into a comb-like shape, and a plurality of remaining portions are cut off. A technique for forming the lead piece 40C is disclosed (see, for example, Patent Document 1). In this technique, even if the current collector is stretched at the mixture coating portion 40A during pressing, a gap is formed between the adjacent lead pieces 40C, thereby reducing distortion of the current collector of the electrode plate 40. Bending can be suppressed.

JP 2001-118561 A

  However, in the technique of Patent Document 1, since the unmixed portion 40B is notched in a comb shape, the end portion of the lead piece 40C is formed on the inner periphery or outer periphery of the electrode group when the electrode plate 40 is wound. In other words, there is a possibility that the uncoated part of one electrode plate is bitten between the mixed material coated part of the other electrode plate and the separator and causes a short circuit.

  This invention makes it a subject to provide the non-aqueous-electrolyte secondary battery which can prevent the short circuit by the biting of a mixture uncoated part while suppressing the curvature of an electrical power collector in view of the said case. .

In order to solve the above problems, the present invention provides an active material mixture coated portion on the surface of the current collector, and the active material mixture is not coated on one side along the longitudinal direction of the current collector. A positive electrode plate having a portion and a negative electrode plate wound through a separator, a non-aqueous electrolyte infiltrating the electrode group, and a battery container containing the electrode group and the non-aqueous electrolyte , wherein the said collector in at least one of the non-application portion of the positive and negative electrode plates, a plurality of apertures is formed at a portion except the outer edge along the elongate direction, said apertures, said Any edge in the direction intersecting the longitudinal direction of the current collector is a curved surface, and the uncoated portion has a protective material for preventing breakage of the current collector on the coated portion side. aqueous electrolyte secondary, characterized in that it is affixed over the elongate direction of the current collector of the opening so as to partially cover It is a battery.

In the present invention, since a plurality of openings capable of reducing the distortion of the current collector to the current collector of the electrode mixture non-application portion is formed, it is possible to suppress the bending of the current collector at the time of press, aperture The length of the current collector is such that any edge in the direction intersecting the longitudinal direction of the current collector is a curved surface, and the protective material partially covers the opening on the coated portion side of the mixture uncoated portion. since affixed over the dimension direction, the current collector of non-application portion which apertures are formed is protected it is possible to prevent breakage of the coating portion Rutotomoni, any apertures also of the collector Since it is formed on the portion excluding the outer edge along the longitudinal direction, the uncoated part is wound in a standing state when winding, and the uncoated part is mixed with the mixed part and separator It is possible to prevent a short circuit without being bitten.

In this case, the opening may have an elliptical shape, and the long axis may be formed in the longitudinal direction of the current collector . Each of the openings may be constituted by two circular openings, and a notch may be formed between the two openings. Further, it may be affixed to at least one of the one or both sides of the coercive Mamoruzai positive negative electrode plate. Furthermore, it is preferable that the protective material has an insulating property, and it is more preferable that the thickness is equal to or less than the thickness of the mixture coating portion.

In the present invention, since a plurality of openings capable of reducing the distortion of the current collector to the current collector of the electrode mixture non-application portion is formed, it is possible to suppress the bending of the current collector at the time of press, aperture The length of the current collector is such that any edge in the direction intersecting the longitudinal direction of the current collector is a curved surface, and the protective material partially covers the opening on the coated portion side of the mixture uncoated portion. since affixed over the dimension direction, the current collector of non-application portion which apertures are formed is protected it is possible to prevent breakage of the coating portion Rutotomoni, any apertures also of the collector Since it is formed on the portion excluding the outer edge along the longitudinal direction, the uncoated part is wound in a standing state when winding, and the uncoated part is mixed with the mixed part and separator It is possible to obtain an effect that it is possible to prevent a short circuit without being bitten.

  Hereinafter, a cylindrical nonaqueous electrolyte secondary battery for a hybrid electric vehicle to which the present invention is applied will be described with reference to the drawings.

(Constitution)
As shown in FIG. 1, the columnar nonaqueous electrolyte secondary battery 20 of the present embodiment includes a nickel-plated iron cylindrical battery case 8. The battery case 8 accommodates an electrode group 4 wound in a cross-sectional spiral shape through a polyethylene separator so that the belt-like positive electrode plate 1 and the negative electrode plate 5 do not directly contact each other. On both sides of the electrode group 4 in the winding axis direction, a mixture uncoated portion 1B of the positive electrode plate 1 and a mixture uncoated portion 5B of the negative electrode plate 5 are arranged on opposite sides. At this time, the mixture uncoated portion 1 </ b> B and the mixture uncoated portion 5 </ b> B are wound in a standing state with respect to both end surfaces of the electrode group 4. An insulation coating (not shown) is applied to the entire outer peripheral surface of the electrode group 4.

  On substantially the extension line of the winding axis of the electrode group 4, the potential from the positive electrode plate 1 and the negative electrode plate 5 made of aluminum, which also serves as a battery cover, is also collected. Copper and disc-shaped negative electrode current collector plates 6 that also serve as battery covers are disposed opposite to both end surfaces of the electrode group 4, respectively. On one surface of the positive electrode current collector plate 2 facing the electrode group 4, the end of the mixture uncoated part 1 B of the positive electrode plate 1, that is, the longitudinal direction of the mixture uncoated part 1 B of the positive electrode plate 1. Are joined by laser welding, and a cylindrical positive electrode terminal 3 made of aluminum and serving as an external terminal is joined to the other surface. Similarly, on one surface of the negative electrode current collector plate 6 facing the electrode group 4, the end of the mixture uncoated part 5 </ b> B of the negative electrode plate 5, that is, the mixture uncoated part 5 </ b> B of the negative electrode plate 5 is formed. The outer edge along the longitudinal direction is joined by laser welding, and a copper-made columnar negative electrode terminal 7 serving as an external terminal is joined to the other surface.

The positive electrode current collector plate 2 and the negative electrode current collector plate 6 are respectively fixed to both ends of the battery container 8 via insulators 9. For this reason, the inside of the non-aqueous electrolyte secondary battery 20 is sealed. Further, a non-aqueous electrolyte solution (not shown) is injected into the battery container 8, and the electrode group 4 is infiltrated with the non-aqueous electrolyte solution. In the non-aqueous electrolyte, 1 mol / liter of lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a mixed solvent in which ethylene carbonate, dimethyl carbonate and diethyl carbonate are mixed at a volume ratio of 30:50:20. Is used.

(Positive electrode plate)
As shown in FIG. 2, the positive electrode plate 1 has an aluminum foil as a strip-shaped current collector with a thickness of 20 μm. A mixture containing a positive electrode active material (active material mixture) is applied substantially uniformly on both surfaces of the aluminum foil. The mixture includes 5 parts of 100 parts by weight of the positive electrode active material lithium manganate powder, 10 parts by weight of the conductive graphite flake graphite, and the binder polyvinylidene fluoride (hereinafter abbreviated as PVDF). Part by weight is mixed. When the mixture is applied, a mixture slurry is prepared by dispersing the mixture in N-methylpyrrolidone (hereinafter abbreviated as NMP), which is a solvent, in a substantially uniform manner. The mixture slurry is applied to both sides of the aluminum foil, leaving one side along the longitudinal direction, and dried. A mixture-coated portion 1A and a mixture-uncoated portion 1B are formed on both surfaces of the current collector, respectively. In order to prevent the aluminum foil from being curved when pressing the mixture-coated portion 1A, the aluminum foil in the mixture-uncoated portion 1B has an elliptical shape in a portion excluding the outer edge along the longitudinal direction of the aluminum foil. A plurality of apertures 10 are formed in a direction in which the major axis intersects the long dimension of the aluminum foil (hereinafter referred to as the width direction). That is, any edge of the opening 10 in the width direction of the aluminum foil (edge on the mixture coating portion 1A side and edge on the outer edge side of the aluminum foil) is a curved surface. Moreover, in the position where each opening 10 was formed, the outer edge part of the aluminum foil in the mixture uncoated part 1B is left without being cut over the entire length direction. After forming the opening 10, the mixture coated portion 1A is pressed so as to have a desired density and thickness, and the positive electrode plate 1 is manufactured.

  Moreover, the tape 13 as a strip | belt-shaped protective material is affixed on the mixture coating part 1A side at the mixture uncoated part 1B of both surfaces of the positive electrode plate 1. The tape 13 plays the role of preventing the aluminum foil from breaking. Moreover, the tape 13 has insulation and is affixed over the full length direction full length of aluminum foil. The thickness of the tape 13 is set to be equal to or less than the thickness of the mixture application portion 1A per one side after the positive electrode plate 1 is pressed. In this example, the tape 13 is an adhesive tape in which a hexamethacrylate adhesive is applied to one side of a polyimide substrate.

(Negative electrode plate)
The negative electrode plate 5 has a thickness of 10 μm and a rolled copper foil as a strip-shaped current collector. A mixture containing a negative electrode active material (active material mixture) is applied to both surfaces of the rolled copper foil substantially uniformly. In the mixture, 90 parts by weight of amorphous carbon powder as the negative electrode active material and 10 parts by weight of PVDF as the binder are mixed. When a mixture is applied, a mixture slurry is produced by dispersing it substantially uniformly in NMP as a solvent. As with the positive electrode plate 1, the mixture slurry is applied to both sides of the rolled copper foil, leaving one side along the longitudinal direction, and dried. A mixture-coated portion 5A and a mixture-uncoated portion 5B are formed on both surfaces of the current collector, respectively. Similarly to the positive electrode plate 1, a plurality of apertures 10 are formed in the unmixed portion 5 </ b> B. After the formation of the opening 10, the mixture coated portion 5A is pressed so as to have a desired density and thickness, and the negative electrode plate 5 is manufactured. Further, similarly to the positive electrode plate 1, the tape 13 is attached to the mixture-coated portion 5 </ b> A side of the mixture-uncoated portion 5 </ b> B on both surfaces of the negative electrode plate 5. The thickness of the tape 13 is set to be equal to or less than the thickness of the mixture coating portion 5A per one side after the negative electrode plate 5 is pressed. In this example, the thickness of the negative electrode plate 5 is adjusted so that the ratio (− / + capacity ratio) between the discharge capacity of the negative electrode and the discharge capacity of the positive electrode is constant at 1.0.

(Action etc.)
Next, the operation and the like of the nonaqueous electrolyte secondary battery 20 of the present embodiment will be described. The mixture uncoated portions 1B and 5B and the opening 10 are formed in the positive electrode plate 1 and the negative electrode plate 5, respectively. Since both have the same function, only the positive electrode plate 1 will be described below. .

  In general, as shown in FIG. 4, in order to improve the volume energy density, the electrode plate 30 in which the mixture coated portion 30A and the mixture uncoated portion 30B are formed on the metal foil of the current collector is substantially uniform. When pressed, the current collector is pressed at the mixture coating portion 30A to cause elongation. On the other hand, the unmixed portion 30B is not compressed and does not stretch. For this reason, the current collector of the electrode plate 30 is distorted and curved. In order to solve this problem, in the conventional non-aqueous electrolyte secondary battery, as shown in FIG. 5, the uncoated part 40B of the electrode plate 40 is notched in a comb-like shape, and the remaining part of the notch is removed. A plurality of lead pieces 40C are formed. Even if the current collector is stretched at the mixture application portion 40A during pressing, the spacing between the adjacent lead pieces 40C is reduced, so that the distortion of the current collector of the electrode plate 40 is reduced and curving is suppressed. be able to. However, when the electrode plate 40 is wound, the end portion of the lead piece 40C may be wound around the inner periphery or the outer periphery of the electrode group. That is, the uncoated portion of one electrode plate is bitten between the mixed portion of the other electrode plate and the separator, which may cause a short circuit when the battery is used. The present embodiment is a non-aqueous electrolyte secondary battery that can solve these problems.

  In the non-aqueous electrolyte secondary battery 20 of the present embodiment, a plurality of apertures 10 are formed in the current collector of the mixture uncoated portion 1B. For this reason, even when elongation occurs in the long dimension of the current collector during pressing of the mixture coated portion 1A, the distortion of the current collector due to elongation is reduced by expanding the aperture 10 in the short diameter direction. can do. Thereby, the curving of the current collector can be suppressed. Moreover, the opening 10 is formed in the part except the outer edge part along the longitudinal direction of a collector. For this reason, since the outer edge of the mixture uncoated part 1B is not cut, the mixture uncoated part 1B can be wound in the standing state during winding. Thereby, since it is not bitten like the lead piece 40C mentioned above at the time of winding, the short circuit between positive-negative electrode plates can be prevented.

  Moreover, only the part of the opening 10 is notched in the mixture uncoated part 1B of the non-aqueous electrolyte secondary battery 20 of the present embodiment. That is, in the unmixed portion 1B, the volume of the cut portion is smaller than that of the uncoated portion 40B that is cut out to the outer edge in a comb shape. For this reason, the cross-sectional area of the mixture uncoated portion 1B connected to the positive electrode current collector plate 2 is increased, and the internal resistance can be reduced. Further, since the cross-sectional area of the unmixed portion 1B is increased, the bonding strength with the positive electrode current collector plate 2 can be improved, and the vibration resistance can be improved.

  Furthermore, the opening 10 of the non-aqueous electrolyte secondary battery 20 of the present embodiment has an elliptical shape and the major axis is formed in the width direction of the current collector. For this reason, the opening 10 has a curved surface at any edge in the direction intersecting the longitudinal direction of the current collector. Thereby, compared with the case where it forms with a square surface, the damage or fracture | rupture of an edge part can be prevented in the mixture coating part 1A side of the opening 10, and the outer edge side of the collector of the opening 10. it can.

  Furthermore, in the non-aqueous electrolyte secondary battery 20 of the present embodiment, the tape 13 is applied to the mixture coated portion 1A side of the mixture uncoated portion 1B on both surfaces of the positive electrode plate 1 over the entire length of the positive electrode plate 1. Has been. For this reason, since the aluminum foil in which the opening 10 is formed is protected, it is possible to prevent the current collector from being damaged, and hence the mixture coating portion 1A from being broken. Moreover, since the tape 13 has insulation, the short circuit by the tape 13 can be prevented. Furthermore, the thickness of the tape 13 is set to be equal to or less than the thickness of the mixture-coated portion 1 </ b> A formed on one surface of the positive electrode plate 1. For this reason, the mixture application part 1A and the mixture application part 1B can be wound in an appropriate manner through the separator without protruding the tape application part.

  In the present embodiment, each of the positive electrode plate 1 and the negative electrode plate 5 is formed with a plurality of apertures 10 in the mixture-uncoated portions 1B and 5B, each having an elliptical shape and a major axis in the width direction of the current collector. Although an example is shown, the present invention is not limited to this. As the shape of the opening 10, if the edge of the opening 10 in the width direction of the current collector is square, the edge of the opening 10 may be broken. It is preferable that any edge in the width direction is formed with a curved surface. As the opening 10 other than the present embodiment, for example, it may be formed in a circular shape, and as shown in FIG. 3 (A), the elliptical shape and the long axis are formed in the longitudinal direction of the current collector. May be. In the case where the opening 10 has an elliptical shape in which the major axis is in the longitudinal direction of the current collector, the opening 10 is formed on the mixture coating portion side in consideration of suppressing the bending that occurs in the current collector during pressing. It is preferable that Further, as shown in FIG. 3B, two circular openings 10 may be formed, and a notch 11 may be formed between the openings 10. Furthermore, although the example in which the opening 10 is formed in each of the positive electrode plate 1 and the negative electrode plate 5 is shown, the opening 10 may be formed in only one of the positive electrode plate 1 and the negative electrode plate 5. In general, since the negative electrode current collector is thinner than the positive electrode current collector, it is preferable that an opening 10 is formed at least in the uncoated part 5B of the negative electrode plate 5.

Moreover, in this embodiment, although the example in which the tape 13 is affixed to the mixture uncoated portions 1B and 5B on both surfaces of the positive electrode plate 1 and the negative electrode plate 5 is shown, the present invention is limited to this. is not. You may affix on only one side of the positive electrode plate 1 and the negative electrode plate 5. Moreover, although it does not restrict | limit especially also in the material of the tape 13, It is preferable to have insulation, in order to avoid the tape 13 having a tolerance to a non-aqueous electrolyte and causing the tape 13 to cause a short circuit. Further, in the present embodiment, an example is shown in which the tape 13 is applied over the entire length of the current collector, but a plurality of strip-shaped tapes 13 can also be applied continuously. Moreover, it cannot be overemphasized that it can replace with the tape 13 and another member which has a protection function which can prevent a fracture | rupture of a collector can be used.

  Furthermore, in this embodiment, although the thickness of the tape 13 showed the example set to below the thickness of the mixture coating parts 1A and 5A per single side | surface of the positive electrode plate 1 and the negative electrode plate 5, this invention is shown. Although it is not limited to this, a gap is formed between the mixture coating portions 1A and 5A and the separator by protruding the tape 13 affixing portion, and the mixture coating portions 1A and 5A are separated from the separator. It becomes impossible to wind it by making it stick closely. In order to avoid this, it is desirable that the thickness of the tape 13 is set to be equal to or less than the thickness per one side of the mixture coated portions 1A and 5A.

  Furthermore, in the present embodiment, lithium manganate is exemplified as the positive electrode active material and amorphous carbon is exemplified as the negative electrode active material, but the present invention is not limited to these. As the positive electrode active material, for example, lithium transition metal double oxides such as lithium cobalt double oxide typified by lithium cobaltate and lithium nickel double oxide typified by lithium nickelate can be used. Alternatively, a lithium transition metal double oxide in which a part of lithium or a transition metal element in a crystal is substituted or doped with another transition metal element such as Fe, Co, Ni, Cr, Al, or Mg may be used. Further, there is no particular limitation on the crystal structure, and the crystal structure may be any of spinel type, layered type, and olivine type. On the other hand, as a negative electrode active material, the carbon material normally used for a nonaqueous electrolyte secondary battery can be used. Examples of the negative electrode active material other than the present embodiment can include various graphite materials such as natural graphite and artificial graphite, coke and the like, and also in the particle shape, layered, scaly, spherical, fibrous, massive, etc. There is no particular limitation. As a power source for HEV, a graphite carbon material having a layered crystal structure causes shrinkage of the crystal structure in an extremely low temperature environment, whereas an amorphous carbon material has a stable crystal structure even in an extremely low temperature environment. Therefore, it is preferable to use an amorphous carbon material. Furthermore, there are no particular limitations on the conductive material, binder, and the like, and materials that are normally used for non-aqueous electrolyte secondary batteries may be used. Moreover, there is no restriction | limiting in particular also about an electrical power collector, You may use the material (a film | membrane, a perforated board, etc.) which has the electroconductivity normally used for a nonaqueous electrolyte secondary battery.

Furthermore, in the present embodiment, the nonaqueous electrolyte solution in which about 6 moles / liter of lithium hexafluorophosphate is dissolved in a mixed solvent such as ethylene carbonate is exemplified, but the nonaqueous electrolyte solution can be used in the present invention. There is no particular limitation on the water electrolyte. The organic solvent is not particularly limited as long as it is usually used for non-aqueous electrolyte secondary batteries. For example, organic solvents such as carbonates, sulfolanes, ethers, and lactones may be used alone or in combination. . Even lithium salt, as long as it is used in conventional non-aqueous electrolyte secondary battery, for _{example, LiClO 4, LiAsF 6, LiBF} 4, LiB (C 6 H 5) 4, CH 3 SO 3 Li, CF ₃ SO ₃ Li or the like or a mixture thereof can be used. Further, the mixing ratio of the organic solvent and the content of the lithium salt are not particularly limited.

  In the present embodiment, a lithium ion non-aqueous electrolyte secondary battery using lithium manganate as the positive electrode active material and amorphous carbon as the negative electrode active material is exemplified, but the present invention is limited to this. However, the present invention can be applied to other nonaqueous electrolyte secondary batteries. Furthermore, in this embodiment, the cylindrical non-aqueous electrolyte secondary battery 20 in which both ends of the cylindrical battery container 8 are sealed with a battery lid that also serves as an external terminal is illustrated, but the present invention is limited to this. is not. For example, the battery may have a rectangular shape or a polygonal shape, and may be a battery in which an electrode group is inserted into a bottomed battery container and a battery lid is caulked and fixed on the upper part of the battery container. Also, the battery capacity, size, etc. are not particularly limited, but the HEV power supply can be suitably used for batteries having a battery capacity of approximately 3 Ah or more.

  Next, examples of the nonaqueous electrolyte secondary battery 20 manufactured according to the present embodiment will be described. In addition, it describes together about the nonaqueous electrolyte secondary battery of the comparative example produced for the comparison.

(Example)
The nonaqueous electrolyte secondary battery 20 of the example was manufactured using the positive electrode plate 1 and the negative electrode plate 5 in which a plurality of elliptical apertures 10 were formed in the mixture uncoated portions 1B and 5B of the current collector ( (See FIG. 2).

(Comparative example)
As shown in FIG. 4, the non-aqueous electrolyte secondary battery of the comparative example is formed by cutting the mixture uncoated portion 40 </ b> B of the electrode plate 40 into a comb-like shape and forming a plurality of lead pieces 40 </ b> C with the remaining portions of the notch. The lead piece 40C was manufactured in the same manner as in the example except that a positive electrode plate and a negative electrode plate obtained by bonding the lead piece 40C to the current collecting component by ultrasonic bonding were used.

(Evaluation 1)
In Evaluation 1, the incidence of short circuit due to biting was evaluated for 200 nonaqueous electrolyte secondary batteries of Examples and Comparative Examples. Each battery was charged, and when high-rate discharge was performed, the battery in which battery abnormality such as a decrease in capacity was observed was disassembled and examined for the presence or absence of a short circuit due to biting. As shown in Table 1 below, from the evaluation result of the short-circuit occurrence rate, it was revealed that the short-circuit due to the biting at the time of winding did not occur in the example compared to the comparative example, and the biting could be prevented.

(Evaluation 2)
In Evaluation 2, the discharge capacity ratio with respect to the discharge rate was evaluated for each of the nonaqueous electrolyte secondary batteries of Examples and Comparative Examples. After charging each battery, the discharge capacities when discharged at discharge rates of 1C, 3C, 5C and 10C were measured, and the discharge capacities of discharge rates of 1C of the nonaqueous electrolyte secondary batteries of Examples and Comparative Examples were measured. The ratio of the discharge capacities of 3C, 5C and 10C was determined as a capacity ratio.

  As shown in FIG. 6, from the evaluation results of the discharge capacity ratio, it has been clarified that the decrease in the discharge capacity accompanying the increase in the discharge rate is smaller in the example than in the comparative example. This is probably because the internal resistance was reduced because the cross-sectional area of the uncoated part of the example was larger than that of the comparative example.

(Evaluation 3)
In Evaluation 3, vibration resistance was evaluated for 10 nonaqueous electrolyte secondary batteries of Examples and Comparative Examples. The nonaqueous electrolyte secondary batteries of Examples and Comparative Examples were each subjected to a vibration test in a three-dimensional direction at a frequency of 5 to 50 Hz. Each battery was disassembled after the vibration test, and the joined state between the positive and negative current collectors and the positive and negative current collectors, that is, the uncoated parts 1B and 5B of the positive and negative electrode plates of the examples and the current collecting leads of the comparative example Were examined for cuts (damage that did not result in cutting) and the presence or absence of cutting. As shown in Table 2 below, the battery of the example did not show any breaks or cuts due to vibration compared to the comparative example. Therefore, it was found that the vibration resistance was improved as compared with the battery of the comparative example.

  The present invention provides a non-aqueous electrolyte secondary battery that can suppress the curving of the current collector and prevent a short circuit due to biting of the uncoated part of the mixture. Since it contributes to the manufacture and sale of secondary batteries, it has industrial applicability.

It is sectional drawing of the columnar nonaqueous electrolyte secondary battery of embodiment to which this invention is applied. It is a top view of the positive / negative electrode board which comprises the nonaqueous electrolyte secondary battery of embodiment. It is a top view which shows another aspect of a positive / negative electrode board, (A) is an elliptical shape, and the long axis is the positive / negative electrode board in which the hole of the length direction of the electrode plate was formed, (B) is two circular shape. The positive and negative electrode plates each having an opening and a notch formed between the openings are shown. It is a perspective view which shows typically the electrode plate curved by the press. It is a top view of the electrode plate which comprises the nonaqueous electrolyte secondary battery of a comparative example. It is a graph which shows the discharge capacity ratio with respect to the discharge rate of a nonaqueous electrolyte secondary battery.

Explanation of symbols

1 Positive electrode plate 1A Mixture coating part (coating part)
1B Mixture uncoated part (uncoated part)
4 Electrode group 5 Negative electrode plate 5A Mixture coating part (coating part)
5B mixture uncoated part (uncoated part)
8 Battery container 10 Open hole
13 tapes (protective material)
20 Cylindrical non-aqueous electrolyte secondary battery (non-aqueous electrolyte secondary battery)

Claims (6)

A positive electrode plate and a negative electrode plate each having a coated portion of the active material mixture on the surface of the current collector and an uncoated portion of the active material mixture on one side along the longitudinal direction of the current collector are separators. An electrode group wound through,
A non-aqueous electrolyte infiltrating the electrode group;
A battery container containing the electrode group and the non-aqueous electrolyte;
With
Wherein the said collector in at least one of the non-application portion of the positive and negative electrode plates, a plurality of apertures is formed at a portion except the outer edge along the elongate direction, said apertures, said current Both edges in the direction intersecting the longitudinal direction of the electric body are curved surfaces,
On the uncoated portion, a protective material for preventing the current collector from being broken is stuck on the coated portion side so as to partially cover the opening. non-aqueous electrolyte secondary battery, characterized by that. The non-aqueous electrolyte secondary battery according to claim 1, wherein the opening has an elliptical shape, and a long axis is formed in a longitudinal direction of the current collector. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein each of the openings is constituted by two circular openings, and a notch is formed between the two openings. . The non-aqueous electrolyte secondary battery according to claim 1 , wherein the protective material is attached to at least one side or both sides of the positive and negative electrode plates. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the protective material has an insulating property. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the protective material has a thickness equal to or less than a thickness of the applied portion.

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