JP2001076761A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the impregnating capability of an electrolyte and safety reliability which are issues in improving an output characteristic and in increasing the size of a nonaqueous electrolyte battery. SOLUTION: In a spirally rolled electrode group 3, a cycle characteristic, an output characteristic and safety reliability are enhanced by providing a hole for each of a positive and negative electrode sheets 4, 6 and by forming a continuous hole 14 communicating with the hole of the positive electrode sheet 4 and the hole of the negative electrode sheet 6 through a separator 5. In addition, by continuing the hole from the rolling center of the electrode group 3 and by forming a hole in the separator 5 at a part interlaid between the holes of the positive and negative electrode sheets, the cycle characteristic and the output characteristic can further be enhanced. Additionally, by forming an internal pressure sensing type safety device 16 at a position of a battery can side face corresponding to the position of the continuous hole, the safety reliability can further be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte secondary battery.

[0002]

2. Description of the Related Art In recent years, small electronic devices such as notebook personal computers and mobile phones have rapidly spread, and mobile computing has been progressing. A secondary battery is used as a power supply for driving such an electronic device. As such a secondary battery, a non-aqueous electrolyte secondary battery having a positive electrode containing a lithium composite metal oxide and a carbonaceous material that absorbs and releases lithium ions as a negative electrode has been developed. As a small battery having a capacity of 5 Wh or less, Many are used.

In the non-aqueous electrolyte secondary battery, both the positive and negative electrodes use a powdery active material, mix it with a conductive agent, and form a sheet on a current collector using a binder. And the electrodes. The electrode sheet is laminated with a separator interposed therebetween to form an electrode group, housed in a container, and added with a non-aqueous electrolyte in which a lithium salt is dissolved as an electrolyte in a non-aqueous solvent.

[0004] At present, it is demanded that the device can be used not only for portable small electronic devices conventionally used but also for various uses. Along with this, a demand for higher capacity has been more and more strongly demanded, and an improvement in output characteristics has also been strongly demanded.

[0005] In order to increase the battery capacity, attempts have been made to increase the amount of lithium ions absorbed and released by the active material and to reduce the thickness of the separator. At the same time, a technique for increasing the size of the battery is required. In order to improve the output characteristics, the use of larger batteries and thinner electrodes are being studied.However, in addition to difficulties in manufacturing, the deterioration of cycle characteristics and the like and the reduction of safety reliability are obstacles. ing.

[0006]

In response to the demand for high output characteristics, shortage of the electrolyte when a large current is used has been one of the obstacles in improving the output characteristics. Further, the nonaqueous electrolyte secondary batteries which are currently commercialized is the mainstream that matches the capacity of about 5Wh volume 16500Mm ² about cylindrical can, when it is intended to further increase in size, the electrode is large Thus, there has been a problem that the impregnating property of the electrolytic solution is lowered and various properties such as capacity and cycle characteristics are lowered. In addition, at the time of an abnormality in which internal heat generation occurs, the heat generation speed is high when the output is increased, and heat is easily accumulated inside a large-sized battery. As a result, in each case, there has been a problem that the thermal reaction easily leads to the runaway reaction and the safety reliability is impaired. The present invention has been made to solve these problems, and provides a non-aqueous electrolyte secondary battery having high output characteristics and a large size non-aqueous electrolyte secondary battery with high safety reliability. The purpose is to do.

[0007]

A nonaqueous electrolyte secondary battery according to the present invention comprises a positive electrode sheet comprising a current collector and an active material layer;
A negative electrode sheet comprising an active material layer containing a carbonaceous material capable of inserting and extracting lithium as an active material and a current collector has an electrode group spirally wound with a separator interposed therebetween. A nonaqueous electrolyte secondary battery in which the electrode group is immersed in an aqueous solvent, wherein the positive electrode sheet,
Both of the negative electrode sheets have holes penetrating the active material layer and the current collector, and the holes on the positive electrode sheet and the holes on the negative electrode sheet overlap with each other via the separator. . By continuous holes, the electrolyte can be impregnated not only from above and below the cylindrical electrode group but also from the side through the holes, and only a uniform impregnation can be obtained in a short time when the electrolyte is injected. In addition, since the electrolyte is quickly supplied from outside the electrode group at the time of discharge, high output characteristics can be obtained. In addition, when the battery group generates heat, heat is exhausted through this hole, thereby improving the safety and reliability of the battery. Gas generated at the time of heat generation can also be discharged to the outside of the electrode group through this hole, so that it is possible to prevent the battery container from exploding due to the formation of a high-pressure part in the electrode group.

In addition to the above features, in the wound electrode group, the holes on the positive electrode sheet and the holes on the negative electrode sheet are continuously provided on the radiation from the innermost circumference to the outermost circumference, so that the electrolyte Is more easily impregnated, and heat and gas in the inner peripheral portion can be discharged, so that a greater effect can be obtained.

Further, the separator sandwiched between the hole on the positive electrode sheet and the hole on the negative electrode sheet provides a hole smaller than the hole on the electrode sheet at a position overlapping with the hole on the electrode sheet. , Heat and gas flow are improved, and a greater effect can be obtained.

[0010] Further, a plurality of electrode sheet holes are provided on the radiation of the electrode group, and a container for accommodating the electrode group is provided at the position on the radiation.
By installing the internal pressure sensing type safety device, higher safety reliability can be obtained. This is an internal pressure sensing type safety device installed not only to discharge gas to the electrode group through this continuous hole when gas is generated due to heat generation due to internal short circuit etc., but also to install this abnormal pressure at a position where gas escapes from the continuous hole. , It is possible to discharge gas out of the battery and to shut off the charge / discharge circuit. Thereby, safety reliability can be further improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-aqueous electrolyte secondary battery according to the present invention will be described below in detail with reference to FIG.

A bottomed cylindrical container 1 made of, for example, stainless steel has an insulating plate 2 disposed at the bottom. The electrode group 3 is housed in the container 1. The electrode group 3 was formed by laminating a positive electrode sheet 4 having a positive electrode active material layer on a current collector and having a hole, a separator 5 and a negative electrode sheet 6 having a negative electrode active material layer on a current collector and having a hole in this order. It has a structure in which a strip is spirally wound. The electrode group having a structure wound on a spiral may be used as it is as a cylindrical battery, or may be crushed and used in a container having a square cross section.

The container 1 contains a non-aqueous electrolyte. Insulating ring 7 separating container 1 and positive electrode terminal
Is placed above the electrode group 3 in the container 1. The sealing plate 8 is disposed at an upper opening of the container 1,
The sealing plate 8 is liquid-tightly fixed to the container 1 by caulking the vicinity of the upper opening inward. The safety valve is arranged between the electrode group 3 and the sealing plate 8. The positive electrode terminal 9 is fitted in the center of the sealing plate 8. One end of the positive electrode lead 10 is connected to the positive electrode 4,
The other end is connected to the positive terminal 9 via a current cutoff valve 12. The negative electrode 6 is connected to the container 1 serving as a negative electrode terminal via a negative electrode lead 13. An internal pressure sensing type safety device 16 can be installed on the extension of the continuous hole 14 or the continuous through hole 15 of the electrode group 3. As the internal pressure sensing type safety device, a safety valve that opens when the internal pressure is equal to or higher than a specified internal pressure and discharges internal gas to the outside of the battery can, a current cutoff valve that cuts off an electric circuit with the outside of the battery when the internal pressure is equal to or higher than a specified internal pressure, A battery deactivator that stops the electrode reaction or releases a substance that reduces the reaction rate can be used.

Next, the structure of the positive electrode sheet 4, the negative electrode sheet 6, the separator 5, the non-aqueous electrolyte, and the electrode group 3 will be specifically described. 1) Configuration of Positive Electrode Sheet The positive electrode sheet 4 is an electrode sheet provided on one or both sides of a current collector with a positive electrode sheet formed into a sheet shape by combining an active material, a conductive material, a binder, and the like. The active material may be any material that absorbs and releases lithium and has a higher potential than the negative electrode 6. For example, LiNiO ₂ , LiCoO _2
2 , a powder of a lithium composite metal oxide such as LiNi _1-x Co _x O ₂ (0 <x ≦ 1) can be used.

The conductive agent is not particularly limited, but acetylene black, natural and artificial graphite of various shapes, coke, and the like can be used.

Examples of the binder include polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVd).
F), ethylene-propylene-diene copolymer, styrene-butadiene rubber and the like can be used.

As the current collector, for example, an aluminum foil, a stainless steel foil, a nickel foil or the like can be used.

The positive electrode active material and the conductive agent can be formed into a sheet by kneading with the addition of the binder. Alternatively, after dissolving and suspending in a solvent such as toluene or N-methylpyrrolidone (NMP) to form a slurry, the slurry may be coated on the current collector and dried to form a sheet. Thereafter, if necessary, the density of the positive electrode sheet can be controlled by performing rolling using a roll press or the like.
Thereafter, holes can be formed on the positive electrode sheet using a punch or the like. The hole is formed so as to penetrate both the positive electrode active material layer and the current collector. Perforation can also be performed at the time of winding the electrode group in order to more easily match the position on the positive electrode sheet with the position on the negative electrode sheet. The shape of the holes may be any shape, but is preferably circular or elliptical. This is because a circular or elliptical shape is less likely to impair the mechanical strength of the electrode sheet. Further, it is more preferable that the elliptical shape is formed by aligning the major radius direction of the ellipse with the longitudinal direction of the electrode sheet, that is, the tangential direction at the time of winding. This is because the force applied during the manufacture of the electrode group and during the use of the battery is in the long direction of the electrode sheet, so that the elliptical hole having a long diameter in this direction is used to minimize the reduction in the strength of the electrode sheet. This is because a hole having a large area can be provided. The position where the holes are provided and the number of holes are not particularly limited, and can be appropriately determined according to the area of the electrode and the number of layers after winding. The size of the hole may be any size as long as the non-aqueous electrolyte can pass through the hole.
The diameter is preferably not less than 5 mm and not more than 5 mm. 0.
If the diameter is 5 mm or less, it is difficult to pass through the non-aqueous electrolyte. If the diameter is 5 mm or more, the mechanical strength of the electrode sheet is impaired and the active material is reduced by that amount, so that the electric capacity of the entire battery is reduced. 2) Configuration of Negative Electrode Sheet The negative electrode sheet 6 is an electrode sheet provided on one or both sides of a current collector with a negative electrode sheet formed into a sheet shape by combining a negative electrode active material, a binder, and the like. It is a carbonaceous material that can store and release lithium.
The carbonaceous material is not particularly limited, but as a raw material, coke or pitch such as petroleum or coal, a low molecular weight organic compound such as natural gas or lower hydrocarbon, polyacrylonitrile, a synthetic polymer such as a phenol resin, and the like. These can be fired at 700 ° C. to 3000 ° C. and carbonized or graphitized to obtain a carbonaceous material. Various shapes such as flakes, fibers, and spheres are possible.

Examples of the binder include polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVd).
F), styrene-butadiene rubber, carboxymethyl cellulose (CMC) and the like can be used.

As the current collector, for example, a copper foil, a stainless steel foil, a nickel foil or the like can be used.

The negative electrode active material and the binder are water, N-
After dissolving and suspending in a solvent such as methylpyrrolidone (NMP) to form a slurry, it can be coated on the current collector and dried to form a sheet. Thereafter, if necessary, the density of the negative electrode sheet can be controlled by performing rolling using a roll press or the like. Thereafter, holes can be formed on the negative electrode sheet using a punch or the like. The hole is formed so as to penetrate both the negative electrode active material layer and the current collector. The perforation is
In order to more easily match the position on the positive electrode sheet with the position on the negative electrode sheet, it can be performed at the time of winding the electrode group.
The shape of the hole may be any shape, and need not be the same as the shape of the hole on the positive electrode sheet. The shape is preferably circular or elliptical. This is because a circular or elliptical shape is less likely to impair the mechanical strength of the electrode sheet. Further, it is more preferable that the elliptical shape is formed in accordance with the major radius direction of the ellipse in the longitudinal direction of the electrode sheet, that is, the tangential direction at the time of winding. This is because the force applied during the manufacture of the electrode group and during the use of the battery is in the long direction of the electrode sheet, so that the elliptical hole having a long diameter in this direction is used to minimize the reduction in the strength of the electrode sheet. This is because a hole having a large area can be provided. The position where the holes are provided and the number of holes are not particularly limited, and can be appropriately determined according to the area of the electrode and the number of layers after winding. The size of the hole may be any size as long as the non-aqueous electrolyte can pass through the hole, and preferably has a diameter of 0.5 mm or more and 5 mm or less as a circumscribed circle. If the diameter is less than 0.5 mm, it is difficult to pass through the non-aqueous electrolyte. If the diameter is more than 5 mm, the mechanical strength of the electrode sheet is impaired and the active material is reduced by that amount, so that the electric capacity of the entire battery is reduced. 3) Separator The separator 5 is formed of, for example, a synthetic resin nonwoven fabric, a polyethylene porous film, or a polypropylene porous film. Holes can also be provided on the separator. By providing the hole at a position overlapping with the holes of the positive electrode sheet and the negative electrode sheet at the time of winding, entry and exit of the electrolyte can be more easily performed. The holes on the separator must be smaller than holes provided on at least one of the positive and negative electrodes in order to avoid contact between the positive and negative electrodes. 4) Configuration of Nonaqueous Electrolyte The nonaqueous electrolyte is composed of at least one or more nonaqueous solvents and at least one or more electrolytes containing lithium. As the non-aqueous solvent, ethylene carbonate, cyclic carbonate such as propylene carbonate,
Cyclic esters such as γ-butyrolactone, chain carbonates such as ethyl methyl carbonate, dimethyl carbonate and diethyl carbonate, tetramethylsulfolane, N-methylpyrrolidone and the like can be used alone or in combination.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (Li
PF ₆ ), lithium borofluoride (LiBF ₄ ), lithium bistrifluoromethylsulfonylimide (LiN
(CF3SO _{2) 2)} is a lithium salt and the like.

In addition to the above, additives such as various surfactants can be added. 5) Electrode group The electrode group 3 includes the positive electrode sheet 4 and the negative electrode sheet 6.
Is wound spirally with the separator 5 interposed therebetween, and the positions of the holes provided on the positive electrode sheet and the holes provided on the negative electrode sheet must be overlapped. When a hole is also provided on the separator, the hole is provided at a position overlapping with the hole on the positive / negative electrode sheet. As shown in the continuous hole 14, the hole needs to be at least one set of positive and negative electrode sheets after winding so that the positions overlap. Further, as shown in the continuous through hole 15 in FIG. 1, a greater effect can be obtained by adjusting the positions of the holes so as to form the through holes from the center to the outer periphery of the cylindrical electrode group.

The non-aqueous electrolyte secondary battery according to the present invention described above has holes provided at overlapping positions during winding, so that the cycle characteristics and output characteristics of the battery can be improved. It is for the following reasons. In the electrolyte injection at the time of battery production, conventionally, there was an infiltration path of the electrolyte only from above and below the cylindrical electrode group. This is because a uniform and sufficient amount of the electrolytic solution can be provided in the electrode group. During the charge / discharge reaction after production, the electrolyte solution enters and exits from the electrode group due to the change in volume of the positive and negative active materials, but the continuous holes facilitate the entry and exit of the electrolyte solution. As a result, the cycle characteristics are improved, and the output characteristics are also improved. By providing holes in the separators between the holes in addition to the holes on the electrode sheet, it is possible to facilitate entry and exit and impregnation of the electrolyte solution described above.
In this case, in order to avoid a short circuit due to electrical contact between the positive and negative electrodes, the holes on the separator must be at least smaller than the holes on either the positive or negative electrode sheet.

In addition to improving cycle characteristics and output characteristics,
Improved safety reliability is also obtained. This is particularly effective when the internal pressure sensing type safety device is provided at a position corresponding to the continuous hole or the continuous through hole of the electrode group on the side surface of the container. It is for the following reasons. When the battery is short-circuited inside, externally heated, or the battery is crushed, an abnormal reaction of the active material occurs in the battery, and heat generation and gas generation accompanying the heat generation occur. Conventionally, the generated gas can move only in a direction parallel to the electrodes in the battery group. If an abnormal reaction occurs at an end other than the end of the electrode group, the safety valve 11 and the current cutoff valve 12 installed at the upper part of the container are used. In some cases, the operation was not in time. Especially two battery containers
When deformed and crushed so as to be divided into two pieces, gas could not be released from the bottom of the battery can, which had no safety valve or current cutoff valve, and was dangerous. In such a large capacity battery having 2500 mAh or more, in such a case, the abnormal reaction in the battery is chained, and there is a possibility of runaway and ignition. On the other hand, when the electrode group has the continuous holes, the gas in the electrode group is easily released to the outside of the battery group together with the heat, so that local concentration and concentration of heat can be reduced, and safety reliability can be improved. Furthermore, by providing an internal pressure sensing type safety device on the side of the container at the position corresponding to the outlet of the continuous hole to the outside of the battery group, the internal pressure rise due to gas generation is sensed, and gas is released to the outside of the container by opening the valve and the circuit is opened. , And the release of the reaction-suppressing substance, etc., and safety reliability can be remarkably improved. (Embodiment) Hereinafter, embodiments of the present invention will be described in detail. Example 1 91% by weight of lithium cobalt oxide (LixCoO ₂ (0.8 ≦ x ≦ 1)) powder having an average particle size of 5 μm, 3% by weight of acetylene black, 3% by weight of graphite, and 3% by weight of polyvinylidene fluoride Add to N-methylpyrrolidone and mix to form a slurry.
After coating on both sides of a current collector made of 5μ aluminum foil,
Hot air drying to remove N-methylpyrrolidone, press,
The positive electrode sheet was produced by cutting. Length 11
50 mm, width 55 mm, coating amount 240 g / side
m ² , the thickness after pressing was 150 μm. Using a punch, a total of 44 circular holes having a diameter of 2 mm were provided at a position of 20 mm from the end of the positive electrode sheet in the width direction and every 50 mm in the length direction.

Further, a mesophase carbon fiber using mesophase pitch as a raw material is heat-treated at 600 ° C. in an argon atmosphere, pulverized to an average particle size of 20 μm, and graphitized at 3000 ° C. in an inert atmosphere to obtain a carbonaceous material. Was manufactured.

96.7% by weight of the carbonaceous material was mixed with 2.2% by weight of styrene-butadiene rubber and 1.1% by weight of carboxymethylcellulose, and a slurry was prepared using water as a solvent. After application to both sides of the body, it was dried. This was pressed and cut to produce a negative electrode sheet. Length 1240mm, width 55m
m, the applied amount was 94 g / m ² per one side, and the thickness after pressing was 142 μm. 44 circular holes having a diameter of 2 mm were provided on the negative electrode sheet in accordance with the positions of the holes on the positive electrode sheet.

After laminating the positive electrode sheet, the separator made of a porous film made of polyethylene and the negative electrode sheet in this order, the positions of the holes on the positive electrode sheet and the holes of the negative electrode sheet are aligned so as to be spiral. To form a cylindrical electrode group.

Further, lithium hexafluorophosphate (LiPF ₆ ) as an electrolyte was replaced with ethylene carbonate (E
C) and 1 mol / L in a mixed solvent of ethyl methyl carbonate (MEC) (volume ratio 34:66) to prepare a non-aqueous electrolyte. The electrode group and the electrolytic solution are accommodated in a bottomed cylindrical container having a stainless steel can diameter of 34.2 mm and a height of 65.0 mm, respectively, except for the aforementioned continuous through hole 15 and the internal pressure sensing type safety device 16. A cylindrical non-aqueous electrolyte secondary battery having the structure shown in FIG. 1 and having 38 continuous holes 14 in FIG. 1 was assembled. (Example 2) After the same positive and negative electrode sheets as in Example 1 were prepared, a circular hole having a diameter of 1.5 mm was formed in a separator portion sandwiched between the corresponding holes on the positive electrode sheet and the holes on the negative electrode sheet. The cylindrical non-aqueous electrolyte secondary battery described above was assembled in the same configuration as in Example 1 except that it was wound in a spiral shape. Example 3 The continuous through-hole 15 shown in FIG. 1 was formed at a position 20 mm from the top and bottom of the electrode group in the width direction, at a position facing the radiation of the electrode group, that is, through the center of the winding of the electrode group. The cylindrical non-aqueous electrolyte described above has the same configuration as that of the first embodiment except that it is provided so as to penetrate the cylindrical electrode group with two 2.5 mm circular continuous through holes and has a total of four continuous through holes. The secondary battery was assembled. (Embodiment 4) A cylindrical non-aqueous electrolyte 2 having the same configuration as that of Embodiment 2 except that a safety valve which opens when the internal pressure rises is provided at a position where the continuous through hole comes into contact with the container 1 is provided. The next battery was assembled. (Comparative Example 1) The above-mentioned cylindrical non-aqueous electrolyte secondary battery was assembled in the same configuration as in Example 1 except that no holes were formed on the positive electrode sheet and the negative electrode sheet. For the obtained cylindrical nonaqueous electrolyte secondary batteries of Examples 1 to 4 and Comparative Example 1, a battery capacity test and a cycle characteristic test were performed. Charge 2000m
After the voltage was increased to 4.2 V at a constant current of A, the charging was performed at a constant voltage so that the total charging time was 5 hours. The rest time between charge and discharge was 30 minutes. By repeating such charge and discharge, the discharge capacity in the second cycle is defined as the battery capacity of each battery,
The number of cycles that reached 70% of this capacity was defined as the cycle life representing the cycle characteristics. Table 1 shows the results.

The cylindrical non-aqueous electrolyte secondary batteries of Examples 1 to 4 and Comparative Example 1 had a discharge capacity (C ₁ ) when discharged at a current of 2000 mA and a discharge capacity (C ₁ ) when discharged at a current of 16000 mA. The discharge capacity (C ₂ ) was measured, and the value of the ratio C ₂ / C ₁ was used as a discharge rate characteristic and is also shown in Table 1.

[Table 1] As is clear from Table 1, it can be seen that the non-aqueous electrolyte secondary batteries of Examples 1 to 4 have excellent cycle characteristics and discharge rate characteristics.

Next, with respect to the cylindrical non-aqueous electrolyte secondary batteries of Examples 1 to 4 and Comparative Example 1, charging was performed at a constant current of 2000 mA to 4.2 V, and a total charging time of 5 at a constant voltage was obtained. I went to time. In this state of charge,
A safety test was performed by crushing the container by lowering a stainless plate having a bottom of 5 mm × 10 mm at the center of the container. Table 2 shows the results.

[Table 2] As can be seen from Table 2, it can be seen that the non-aqueous electrolyte secondary batteries of Examples 1 to 4 achieve higher safety reliability than Comparative Example 1.

Therefore, by providing the electrode group with the continuous holes or the continuous through holes as described above, the cycle characteristics, output characteristics and safety reliability were improved. Further, by providing an internal pressure sensing type safety device at a position corresponding to the hole, it has become possible to realize higher safety reliability.

[0033]

As described above, according to the present invention,
It is possible to provide a non-aqueous electrolyte secondary battery that achieves high cycle characteristics and high output characteristics at the same time and further enhances safety reliability.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an example of a cylindrical non-aqueous electrolyte secondary battery according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Insulating plate, 3 ... Electrode group, 4
..Positive electrode sheet, 5 ... Separator, 6 ... Negative electrode sheet, 7 ... Insulating ring, 8 ... Sealing plate, 9 ...
Positive electrode terminal, 10: positive electrode tab, 11: safety valve, 1
2 ... current cutoff valve, 13 ... negative electrode tab, 14 ...
Continuous hole, 15 ... Continuous through hole, 16 ... Internal pressure sensing type safety device.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Sato 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. (72) Inventor Hideyuki Kanai 72 Horikawa-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture F-term (reference) 5H012 AA01 BB01 CC01 CC09 FF00 FF01 5H014 AA02 AA06 CC04 5H028 AA01 AA07 BB07 BB19 CC00 CC08 CC12 5H029 AJ02 AJ03 AJ05 AJ12 AK03 AL06 AL07 AM02 AM03 AM05 AM07 BJ02 BJ14 BJ27 CJ04 CJ07 CJ13 DJ02 DJ04 DJ07

Claims (4)

[Claims] 1. A positive electrode sheet comprising a current collector and an active material layer,
A negative electrode sheet comprising an active material layer containing a carbonaceous material capable of inserting and extracting lithium as an active material and a current collector has an electrode group spirally wound with a separator interposed therebetween. A nonaqueous electrolyte secondary battery in which the electrode group is immersed in an aqueous solvent, wherein the positive electrode sheet,
Both of the negative electrode sheets have holes penetrating the active material layer and the current collector, and the holes on the positive electrode sheet and the holes on the negative electrode sheet overlap with each other via the separator. Non-aqueous electrolyte secondary battery. 2. The wound electrode group, wherein the holes on the positive electrode sheet and the holes on the negative electrode sheet continuously overlap on the radiation from the innermost circumference to the outermost circumference. Non-aqueous electrolyte secondary battery. 3. A portion of the separator sandwiched between the hole on the positive electrode sheet and the hole on the negative electrode sheet is provided with a hole smaller than at least one of the holes on the electrode sheet at a position overlapping the hole on the electrode sheet. The non-aqueous electrolyte secondary battery according to claim 1, wherein: 4. An internal pressure sensing type safety device is provided at a position on the radiation of an outer container for accommodating the electrode group, which has a hole on the electrode provided at a position continuous on the radiation of the electrode group. The non-aqueous electrolyte secondary battery according to claim 1, wherein: