JP2003031266A - Flat nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat nonaqueous secondary battery improved in discharge capacity. SOLUTION: This flat nonaqueous secondary battery is provided with a sealed container provided by crimping and fixing a positive electrode container 1 and a negative electrode container 2 through an insulation gasket 3, and an electrode group 4 housed in the sealed container and composed by rolling, in a spiral shape, a laminate provided with a positive electrode including a positive electrode collector and a negative electrode including a negative electrode collector. The battery is characterized in that an end part of the positive electrode collector or the negative electrode collector is projected on one rolling surface of the electrode group, and the projected end part is bent to bring it into contact with the inside surface of the container, out of the positive electrode container and the negative electrode container, having the same polarity as the projected end part.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat non-aqueous secondary battery. 2. Description of the Related Art Small non-aqueous electrolyte batteries, such as coin-type or button-type non-aqueous electrolyte batteries, have been mainly used as a main power supply for a small device or a backup power supply for a recording element. In each case, the power consumption is very small and is intended for long-term use, and the structure is such that a pellet-shaped positive electrode is stored in a metal positive electrode case, and a pellet-shaped negative electrode is stored in a metal negative electrode case. It has been known that a separator is interposed between an anode and a negative electrode. According to such a structure, since the reaction area between the positive electrode and the negative electrode is small, the reactivity is low, and discharge can be performed only with a small current. On the other hand, cylindrical batteries and prismatic batteries used in mobile phones and electronic devices use a spirally wound electrode group with a separator interposed between a belt-like positive electrode and a negative electrode, so that a large current is required. Discharge is possible. Further, there is a degree of freedom in designing the thickness and area of the electrode according to the required load and capacity of the electronic device. [0004] By the way, a coin-type or button-type nonaqueous electrolyte battery also needs to flow a large current in order to diversify the purpose of use. In order to allow a large current to flow, it is necessary to increase the reaction area of the electrode, and it is necessary to form a wound structure like a cylindrical battery or a prismatic battery. There is a method of crushing a wound electrode into a thin rectangular shape in a flat type container used for a coin type or button type battery (for example, Japanese Patent Application Laid-Open No. 2000-164259). When a square electrode group is accommodated in a cylindrical container, a problem arises in that wasteful space increases. To solve such a problem, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 1-345626 proposes that the height of the winding in the central axis direction be smaller than the size in the direction perpendicular to the central axis. However, Japanese Patent Application Laid-Open No. H11-345626 discloses
In the battery described in Japanese Unexamined Patent Application Publication No. H11-284, a high discharge capacity cannot be obtained because electrical connection is established by contact between the tab and the container. SUMMARY OF THE INVENTION An object of the present invention is to provide a flat type non-aqueous secondary battery having an improved discharge capacity. [0008] A flat nonaqueous secondary battery according to the present invention comprises: a sealed container obtained by caulking and fixing a positive electrode container and a negative electrode container via an insulating gasket; A flat non-aqueous secondary battery comprising: an electrode group housed in a spirally wound laminate including a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector, An end of the positive electrode current collector or the negative electrode current collector protrudes from one winding surface of an electrode group, and the protruded end is bent to form the protruding end of the positive electrode container and the negative electrode container. It is characterized by being brought into contact with the inner surface of a container having the same polarity. DETAILED DESCRIPTION OF THE INVENTION An example of a flat type non-aqueous secondary battery according to the present invention will be described. The flat type non-aqueous secondary battery includes a sealed container obtained by caulking and fixing a positive electrode container and a negative electrode container via an insulating gasket, and is housed in the sealed container.
An electrode group in which a laminate including a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector is spirally wound. A separator can be arranged between the positive electrode and the negative electrode. The flat type non-aqueous secondary battery can have the structures described in the following (a) to (c). (A) An end of the positive electrode current collector is protruded from one of the winding surfaces of the electrode group, and the protruded end is bent and brought into contact with the inner surface of the positive electrode container. (B) An end of the negative electrode current collector is protruded from one of the winding surfaces of the electrode group, and the protruded end is bent and brought into contact with the inner surface of the negative electrode container. (C) An end of the positive electrode current collector is protruded from one of the winding surfaces of the electrode group, and the protruded end is bent and brought into contact with the inner surface of the positive electrode container. Further, an end of the negative electrode current collector is projected from the other winding surface of the electrode group,
The protruding end is bent to contact the inner surface of the negative electrode container. Here, the winding surface means a surface perpendicular to the winding axis of the electrode group. According to the configuration (c) of the above (a) to (c), the discharge capacity can be greatly improved, so that it is desirable. In the above-described configurations (a) to (c),
It is preferable that the end of the negative electrode active material containing layer protrudes from the end of the positive electrode active material containing layer. This is because, when the end of the negative electrode active material-containing layer faces the positive electrode active material-containing layer, lithium dendrite is likely to precipitate at the end of the negative electrode active material-containing layer. In the above arrangements (a) to (c),
The end protruding from the winding surface can be bent toward the outer circumference or the inner circumference of the electrode group. Bending to the inner peripheral side is preferable because an internal short circuit hardly occurs. In the electrode group, the length in the direction perpendicular to the winding axis is preferably longer than the length in the winding axis direction. With such a configuration, a thin nonaqueous electrolyte battery having a high energy density can be obtained. Hereinafter, the positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte will be described. 1) Positive electrode This positive electrode is formed of a current collector in which a positive electrode layer containing an active material and a conductive material is supported. Examples of the active material include various oxides (eg, lithium manganese composite oxide such as LiMn ₂ O ₄ , manganese dioxide, lithium nickel composite oxide such as LiNiO ₂ , lithium lithium composite oxide such as LiCoO _2, etc.). Composite oxides, lithium cobalt nickel composite oxides, amorphous vanadium pentoxide containing lithium, and the like, and chalcogen compounds (for example, titanium disulfide, molybdenum disulfide, and the like) can be given. Among them, it is preferable to use a lithium manganese composite oxide, a lithium cobalt composite oxide, and a lithium nickel composite oxide. As the current collector, for example, expanded metal made of aluminum, aluminum foil, aluminum mesh, punched metal made of aluminum, or the like can be used. Examples of the conductive material (conductive filler) include carbon black (eg, acetylene black, furnace black, Ketjen black, etc.), graphites (eg, artificial graphite, powdered graphite, powdered expanded graphite, etc.). ), Pulverized glassy carbon, pulverized or crushed coke, pulverized carbon fiber, pulverized graphitized carbon fiber, nickel powder and the like. The conductive material may be used alone or in combination of two or more. The positive electrode is prepared by, for example, kneading a positive electrode active material, a conductive material, and a binder in the presence of a solvent to prepare a slurry, applying the slurry to a current collector, drying the slurry, and pressing the slurry. It is produced by performing molding. Examples of the binder include polyvinylidene fluoride, styrene / butadiene copolymer, carboxymethylcellulose and derivatives thereof. 2) Negative electrode This negative electrode is formed of a negative electrode layer containing an active material supported on a current collector. [0028] Examples of the active material include a carbonaceous material that stores and releases lithium ions. Such carbonaceous materials include, for example, those obtained by firing organic polymer compounds (eg, phenolic resin, polyacrylonitrile, cellulose, etc.), those obtained by firing coke, mesophase pitch, and artificial graphite. And carbonaceous materials represented by natural graphite and the like. Among them, it is preferable to use a carbonaceous material obtained by firing the mesophase pitch under a normal pressure or a reduced pressure at a temperature of 500 to 3000 ° C. in an inert gas atmosphere such as an argon gas or a nitrogen gas. As the current collector, for example, copper expanded metal, copper foil, copper mesh, copper punched metal, and the like can be used. The negative electrode is allowed to contain a conductive material (conductive filler). Examples of the conductive material (conductive filler) include the same materials as those described for the positive electrode. The negative electrode is prepared by, for example, preparing a slurry by kneading a negative electrode active material and a binder in the presence of a solvent, applying the slurry to a current collector, drying the slurry, and then performing press molding. It is produced by Examples of the binder include those similar to those described above for the positive electrode. 3) Separator The separator may be of any type as long as it allows lithium ions to move while separating the positive and negative electrodes. As such a separator, for example, a microporous membrane or a nonwoven fabric containing a polyolefin (for example, polyethylene or polypropylene) as a main component can be used. 4) Non-aqueous electrolyte The non-aqueous electrolyte is prepared, for example, by dissolving an electrolyte in a non-aqueous solvent. Examples of the non-aqueous solvent include ethylene carbonate (EC) and propylene carbonate (P
C), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC),
Ethyl methyl carbonate (EMC), γ-butyrolactone (γ-BL), sulfolane, acetonitrile, 1,
2-dimethoxyethane, 1,3-dimethoxypropane,
Dimethyl ether, tetrahydrofuran (THF), 2
-Methyltetrahydrofuran and the like.
The non-aqueous solvents may be used alone or as a mixture of two or more. Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (L
iPF _6), lithium borofluoride (LiBF _4), lithium hexafluoroarsenate (LiAsF _6), lithium salts such as lithium trifluoromethane sulfonate (LiCF ₃ SO ₃₎ may be mentioned. The electrolytes may be used alone or in combination of two or more. The amount of the electrolyte dissolved in the non-aqueous solvent is desirably in the range of 0.2 mol / L to 2 mol / L. One example of the flat type non-aqueous secondary battery according to the present invention is shown in FIGS. FIG. 1 is a cross-sectional view illustrating an example of the flat nonaqueous secondary battery according to the present invention (for example, a coin-type nonaqueous secondary battery). An electrode group 4 is provided in a closed container in which a bottomed cylindrical negative electrode container (cap) 2 is caulked and fixed to a bottomed cylindrical positive electrode container (outer can) 1 via an insulating gasket 3.
Is stored. The electrode group 4 is produced, for example, by being spirally wound with a separator 5 interposed between a positive electrode and a negative electrode. A negative electrode current collector 6 protrudes from one of the winding surfaces of the electrode group 4, and the protruding negative electrode current collector 6 is bent inward to be in contact with the inner surface of the negative electrode container 2. The positive electrode current collector 7 protrudes from the other winding surface of the electrode group 4, and the protruding positive electrode current collector 7 is bent inward to be in contact with the inner surface of the positive electrode container 1. The non-aqueous electrolyte is impregnated in the electrode group 4. The flat nonaqueous secondary battery according to the present invention described above comprises a sealed container obtained by caulking and fixing a positive electrode container and a negative electrode container via an insulating gasket, and a positive electrode container housed in the closed container. An electrode group in which a laminate including a positive electrode including a current collector and a negative electrode including a negative electrode current collector is spirally wound. An end of the positive electrode current collector or the negative electrode current collector is protruded from one of the winding surfaces of the electrode group, and the protruded end is bent to form the protruded end of the positive electrode container and the negative electrode container. And contact the inner surface of the container with the same polarity. If the length of the electrode group in the direction perpendicular to the winding axis is made longer than the length of the electrode group in the direction of the winding axis in order to increase the energy density of the flat type battery, the electrode group will be shoddy due to handling during manufacture. It becomes easy to cause winding deviation and decomposition that deform into a shape. According to the present invention, even when the length in the direction orthogonal to the winding axis is longer than the length in the winding axis direction of the electrode group,
The bent portion can prevent the electrode or separator near the center of the winding surface from protruding outward, and can reduce winding deviation and decomposition of the electrode group during manufacturing. Further, since the end protruding from the winding surface is bent without a cut, a repulsive force for returning the bent portion to the original shape is apt to act, and the protruding end is formed. The contact area with the inner surface of the container can be improved. As a result, the internal resistance of the battery can be reduced, so that the discharge capacity can be improved. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a plan view showing the positional relationship between the positive electrode, the negative electrode, and the separator of the electrode group in the coin-type non-aqueous secondary battery of FIG. 1, and FIG. 3 is a sectional view taken along the line III-III of FIG. FIG. 4 is a schematic diagram showing a spirally wound body of the positive electrode, the separator and the negative electrode of FIG. 2, and FIG. 5 is a diagram showing a negative electrode assembly protruding from one of the winding surfaces of the wound body of FIG. It is sectional drawing which shows the state which bent the electric body to the inner peripheral side. (Example 1) <Preparation of positive electrode> Polyvinylidene fluoride (trade name: # 110, manufactured by Kureha Chemical Industry) was added to 25 parts by mass of N-methylpyrrolidone.
0) After dissolving 3 parts by mass, 89 parts by mass of LiCoO ₂ having an average particle diameter of 3 μm as a positive electrode active material and 8 parts by mass of graphite (trade name: KS6 manufactured by Lonza) as a conductive material were added, and a dissolver and The mixture was stirred and mixed using a bead mill to prepare a positive electrode slurry. This slurry was applied on both sides of a 15 μm-thick aluminum foil as a current collector at regular intervals using a dice coater, dried, pressed, and slit to have a structure shown in FIG. 2, The thickness is 200 μm, and the width of the positive electrode active material containing layer 8 is 2
mm, positive electrode active material containing layer non-holding area 7 (positive electrode current collector)
Of the reel-shaped positive electrode 9 having a width of 1.5 mm and a width of 3.5 mm
Got. <Preparation of Negative Electrode> To 100 parts by mass of mesophase pitch-based carbon fiber powder (manufactured by Petka), 10 parts by mass of graphite powder (trade name: KS15 manufactured by Lonza) was added and mixed. Butadiene latex (trade name: L1571, manufactured by Asahi Chemical Industry Co., Ltd., solid content: 4)
4.2 parts by mass) and carboxymethyl cellulose as a thickening agent (trade name of Daiichi Kogyo Seiyaku Co., Ltd .: BSH12)
130 parts by mass of an aqueous solution (solid content 1% by weight) of distilled water 2
And 0 parts by mass and mixed to prepare a slurry. This slurry was coated on both sides of a copper foil having a thickness of 10 μm at regular intervals using a dice coater, dried, pressed, and slit to have a structure shown in FIG. 2 and a thickness of 200 μm. , The width of the negative electrode active material containing layer 10 is 3 mm,
The width of the negative electrode active material-containing layer non-holding region 6 (negative electrode current collector) was 1.5 mm, and the width of the reel-shaped negative electrode 11 was 4.5 mm. <Preparation of Electrode Group> A band-shaped polyethylene porous membrane having a width of 4 mm was prepared as the separator 5. After the active material-containing layer 8 of the positive electrode 9 is opposed to the central portion of the active material-containing layer 10 of the negative electrode 11, the separator 5 is provided between the positive electrode 9 and the negative electrode 11 and outside the positive electrode 9, on the long side of the separator 5. It arrange | positioned so that the edge part of the negative electrode collector 6 may protrude from one end, and the edge part of the positive electrode collector 7 may protrude from the other end. The obtained laminate is spirally wound, and as shown in FIG.
The winding end of the obtained wound body 12 is adhered to an adhesive tape 13.
Fixed with. Next, as shown in FIG. 5, the negative electrode current collector 6 protruding from one of the winding surfaces of the wound body 12 was tilted inward at an interval of 90 ° to be entirely bent. Further, the positive electrode current collector 7 protruding from the other winding surface of the wound body 12 is tilted to the inner peripheral side every 90 ° and the whole is bent to have a diameter of 20 mm and a height of 4.5.
The electrode group 4 of mm was obtained. <Preparation of Nonaqueous Electrolyte> Ethylene carbonate (EC) and γ-butyl lactone (γ-BL) were mixed at a volume ratio of 1: 3, and L was used as an electrolyte in the obtained mixed solvent.
A non-aqueous electrolyte was prepared by dissolving 1.5 mol / L of iBF ₄ . <Assembly of Battery> A battery container of 2450 size (diameter 24 mm, height 5 mm) was used. The electrode group 4 is housed in the positive electrode container 1 such that the bent portion of the positive electrode current collector 7 is in contact with the inner surface of the bottom of the positive electrode container 1.
Drying under reduced pressure was performed for 4 hours. Next, after cooling to room temperature, 0.6 g of the non-aqueous electrolyte was injected. After the annular insulating gasket 3 is attached to the opening end of the negative electrode container 2, the negative electrode container 2 is caulked and fixed to the positive electrode container 1.
The bent portion of the negative electrode current collector 6 was brought into contact with the inner surface of the negative electrode container 2 to obtain a coin-type non-aqueous secondary battery having the structure shown in FIG. Example 2 <Preparation of Negative Electrode> A slurry similar to that described in Example 1 was applied to both surfaces of a copper foil having a thickness of 10 μm at regular intervals using a dice coater, and dried. Then, by pressing and slitting, a reel-shaped negative electrode having a thickness of 200 μm, a width of the negative electrode active material-containing layer of 3 mm, and no negative electrode active material-containing layer non-holding region was obtained. After removing the negative electrode active material-containing layer at the short side end of the negative electrode, a nickel tab was welded. <Preparation of Electrode Group> After the active material-containing layer of the positive electrode was opposed to the central portion of the active material-containing layer of the negative electrode, the electrode described in Example 1 was provided between the positive electrode and the negative electrode and outside the positive electrode. A separator similar to the above was disposed such that the end of the positive electrode current collector protruded from one end of the long side of the separator. The obtained laminate was spirally wound, and the end of the wound end of the obtained wound body was fixed with an adhesive tape. Next, the entirety of the positive electrode current collector protruding from the other winding surface of the wound body is bent by being tilted inward at 90 ° intervals to obtain an electrode group having a diameter of 20 mm and a height of 4.5 mm. Was. <Assembly of Battery> A battery container having the same size as that described in Example 1 was used.
The electrode group was housed in the positive electrode container such that the bent portion of the positive electrode current collector was in contact with the container bottom, and was dried under reduced pressure at 80 ° C. for 24 hours. Next, after cooling to room temperature, 0.6 g of the same nonaqueous electrolyte as described in Example 1 was injected. After attaching an annular insulating gasket to the opening end of the negative electrode container, the negative electrode container was caulked and fixed to the positive electrode container, thereby bringing the negative electrode tab into contact with the inner surface of the negative electrode container to obtain a coin-type non-aqueous secondary battery. (Comparative Example 1) First, an electrode group was prepared by the method shown in FIGS. <Preparation of Positive Electrode> A slurry similar to that described in Example 1 was applied to both surfaces of a 15 μm-thick aluminum foil as a current collector at regular intervals using a dice coater, and dried. By pressing and slitting, the thickness is 200 μm, the width of the positive electrode active material-containing layer is 2.0 mm, and the width is 0.5 m on both sides of the positive electrode active material-containing layer.
m, and a reel-shaped positive electrode having a width of 3.0 mm was obtained. After removing the positive electrode active material-containing layer at the end 13 in the short side direction of the positive electrode, a tab 14 made of aluminum was welded. <Preparation of Negative Electrode> A slurry similar to that described in Example 1 was applied to both surfaces of a copper foil having a thickness of 10 μm at regular intervals using a dice coater, and dried.
Pressing and slitting, the thickness is 200μm
Thus, a reel-shaped negative electrode having a width of the negative electrode active material-containing layer of 3 mm and having no negative electrode active material-containing layer non-holding region was obtained. After removing the negative electrode active material-containing layer at the short end 15 of the negative electrode, a nickel tab 16 was welded. <Preparation of Electrode Group> A belt-shaped polyethylene porous membrane having a width of 4 mm was prepared as the separator 17. After the active material-containing layer of the positive electrode is opposed to the central portion of the active material-containing layer of the negative electrode similar to that described in Example 2 described above, the same as described in Example 1 described above between the positive electrode and the negative electrode. A similar separator 17 was provided. Subsequently, a separator 17 was further disposed on the positive electrode side of the laminate. The obtained laminate was spirally wound, and the winding end end of the obtained wound body was fixed with an adhesive tape 18 to obtain an electrode group 19 in which a separator protruded from both winding surfaces. <Assembly of Battery> A battery container having the same size as that described in Example 1 was used.
The electrode group was accommodated in the positive electrode container such that the positive electrode tab and the inner surface of the container were in contact with each other, and dried under reduced pressure at 80 ° C. for 24 hours. Next, after cooling to room temperature, 0.6 g of the same nonaqueous electrolyte as described in Example 1 was injected. After attaching an annular insulating gasket to the opening end of the negative electrode container, the negative electrode container was caulked and fixed to the positive electrode container, thereby bringing the negative electrode tab into contact with the inner surface of the negative electrode container to obtain a coin-type non-aqueous secondary battery. (Comparative Example 2) <Preparation of Electrode Group> A wound body was prepared in the same manner as described in Example 1 described above. Cuts parallel to the winding axis were formed at equal intervals in the negative electrode current collector protruding from one of the winding surfaces of the wound body, and then the negative electrode current collector was bent inward. Further, after forming cuts parallel to the winding axis at equal intervals on the positive electrode current collector protruding from the other winding surface of the wound body, the positive electrode current collector was bent to the inner peripheral side to have a diameter of 20 mm and a height of 20 mm. 4.5m
m electrode groups were obtained. <Assembly of Battery> A battery container having the same size as that described in Example 1 was used.
The electrode group was housed in the positive electrode container such that the bent portion of the positive electrode current collector was in contact with the inner surface of the bottom of the positive electrode container, and was dried under reduced pressure at 80 ° C. for 24 hours. Then, after cooling to room temperature, 0.6 g of the same nonaqueous electrolytic solution as described in Example 1 described above.
Was injected. After attaching an annular insulating gasket to the opening end of the negative electrode container, the negative electrode container is caulked and fixed to the positive electrode container so that the bent portion of the negative electrode current collector contacts the inner surface of the negative electrode container, and a coin-shaped non-aqueous secondary I got a battery. After the obtained secondary batteries of Examples 1 and 2 and Comparative Examples 1 and 2 were injected, they were aged at room temperature for 24 hours. Next, the battery was charged at a constant current and a constant voltage of 10 mA corresponding to 0.2 C for 10 hours, and then subjected to a charge / discharge cycle of discharging at 10 mA. The discharge capacity and the internal resistance at the first cycle, the 50th cycle and the 100th cycle were measured, and the results are shown in Table 1 below. For the secondary batteries of Examples 1 and 2 and Comparative Examples 1 and 2, the number (in 100 electrode groups) of each of the electrode groups whose winding deviation occurred was measured by the method described below. Are shown in Table 1 below. That is, the shape of the electrode group was observed by dropping the electrode group from a height of 20 cm. In the vertical direction (winding axis direction) of the electrode group, a product within +0.5 mm (maximum total height of 5.0 mm) was regarded as a non-defective product, and one exceeding +0.5 mm was regarded as a winding deviation. [Table 1] As is clear from Table 1, the secondary batteries of Examples 1 and 2 have higher discharge capacity and lower internal resistance than Comparative Examples 1 and 2. In addition, according to the secondary batteries of Examples 1 and 2, it can be seen that the spiral shape of the electrode group can be prevented from being broken by handling during the manufacturing process. On the other hand, according to the secondary battery of Comparative Example 2, the internal resistance increased because the current collector protruding from the winding surface of the electrode group was cut inward and then bent inward. ,
This is considered to be due to the fact that the shape of the bent portion is easily deformed, the repulsive force of the bent portion is weakened, and uneven contact is likely to occur. In addition, the effect of fixing the positions of the positive electrode and the negative electrode and the separator is weakened by the formation of the cut in the bent portion, and it is presumed that the shape of the electrode group is easily deformed into a bamboo shoot shape. As described in detail above, according to the present invention, a flat non-aqueous secondary battery having a low internal resistance and a high discharge capacity can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of a flat nonaqueous secondary battery according to the present invention (for example, a coin-type nonaqueous secondary battery). FIG. 2 is a plan view showing a positional relationship between a positive electrode, a negative electrode, and a separator of an electrode group in the coin-type non-aqueous secondary battery of FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. 2; FIG. 4 is a schematic view showing a spirally wound body of the positive electrode, the separator, and the negative electrode of FIG. 2; FIG. 5 is a cross-sectional view showing a state in which a negative electrode current collector protruding from one of the winding surfaces of the wound body in FIG. 4 is bent inward. FIG. 6 is a plan view showing a positional relationship between a positive electrode, a negative electrode, and a separator of an electrode group in a coin-type nonaqueous secondary battery of Comparative Example 1. FIG. 7 is a schematic diagram showing an electrode group in a coin-type non-aqueous secondary battery of Comparative Example 1. [Description of Signs] 1 ... Positive electrode container, 2 ... Negative electrode container, 3 ... Insulating gasket, 4 ... Electrode group, 5 ... Separator, 6 ... Negative electrode active material containing layer holding area (negative electrode current collector), 7 ... Positive electrode active Material-containing layer non-holding area (positive electrode current collector).

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Claims (1)

Claims: 1. An airtight container obtained by caulking and fixing a positive electrode container and a negative electrode container via an insulating gasket;
A flat non-aqueous secondary battery including an electrode group housed in the closed container and spirally winding a laminate including a positive electrode including a positive electrode current collector and a negative electrode including a negative electrode current collector. An end of the positive electrode current collector or the negative electrode current collector protrudes from one of the winding surfaces of the electrode group, and the protruded end is bent to protrude from the positive electrode container and the negative electrode container. A flat type non-aqueous secondary battery characterized by being brought into contact with an inner surface of a container having the same polarity as an end.