JP2003123830A - Flat cell and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat cell, and its manufacturing method, with which a loss in manufacturing a group of electrode plates is reduced and which is easy to be manufactured. SOLUTION: A positive electrode lead 13 is welded and connected to one end of a positive electrode plate and a negative electrode lead 14 to one end of a negative electrode plate, composing a group of electrodes 10. The negative electrode lead 14 is welded and connected to a sealing case 5 and the positive electrode lead 13 to a cap case 4. As the electrode plates and the leads are of separate bodies, optimal material can be selected for each, leading to reduction of material loss in manufacturing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores a pole plate group having a winding structure in an outer case formed by combining a cap case and a sealing case formed in a half shell with their openings facing each other. The present invention also relates to a flat battery having improved high load current characteristics as a flat battery and a manufacturing method thereof.

[0002]

2. Description of the Related Art Since flat type batteries such as button type batteries and coin type batteries are small and thin, when features such as wristwatches and hearing aids are required to be downsized, and card type devices are thin type. It is widely used when it is required.

A coin-shaped battery, which is a typical form of a flat battery, has a disk-shaped positive electrode pellet 3 in a sealing case 35 formed in a circular half-shell as shown in FIG.
2 and the negative electrode pellet 33 are opposed to each other via the separator 34, and after injecting the electrolytic solution, the cap case 31 is arranged at the opening of the sealing case 35 via the gasket 36.
The internal space is sealed by a caulking seal in which the open end of the cap case 31 is bent inward to form a coin-shaped battery.

In the structure of the coin type battery in which the positive electrode pellet 32 and the negative electrode pellet 33 face each other at a ratio of 1: 1, the continuous discharge current is caused by factors such as a small reaction area where the positive electrode plate and the negative electrode plate are opposed to each other. 10 mA at most
However, there is a problem that it can be applied only to a device having a small load current.

In order to take out a large discharge current, it is necessary to increase the counter electrode area between the positive electrode plate and the negative electrode plate. In batteries other than flat type batteries, a plurality of positive electrode plates and negative electrode plates are interposed via a separator. A structure in which a reaction area is increased is widely used by a laminated structure in which layers are laminated or a spiral structure in which a separator is disposed between a strip-shaped positive electrode plate and a negative electrode plate and is spirally wound. Such a laminated or wound electrode plate,
If the battery can be housed in a flat-shaped outer case having a small height dimension like a coin-shaped battery, a flat battery with an increased discharge current can be realized. A flat battery that achieves this has been proposed by the applicant of the present invention, and is disclosed in JP 2000
The one disclosed in Japanese Unexamined Patent Publication No. 360728 is known. Also, Japanese Patent Application Nos. 2000-330916 and 200
No. 0-360728 proposes a flat battery in which an electrode group having a winding structure is housed in a rectangular or circular outer case.

When an electrode group having a wound structure is used to increase the discharge capacity, the connection from the electrode group to the positive electrode and the negative electrode of the battery is often adopted in the flat battery having the conventional structure. In the case of contact, loss due to contact resistance occurs. Therefore, in the above-mentioned prior application example, a connection method by welding is adopted for connection of the battery of the electrode plate group to the positive electrode and the negative electrode, and the internal resistance is reduced to cope with a large discharge current.

A flat battery using the wound electrode group 1 has a cap case 4 and a sealing case 5 formed in a half shell via a gasket 6, as shown in a sectional view in FIG. The electrode plate group 1 is housed in a combined outer case, the positive electrode lead 15 pulled out from the electrode plate group 1 is welded to the inner surface of the cap case 4 at the welding point (A), and the negative electrode lead 16 is the inner surface of the sealing case 5. Are welded at the welding point (B). Therefore, the cap case 4 constitutes the positive electrode of the battery, and the sealing case 5 constitutes the negative electrode of the battery, and is used for external connection.

As shown in FIG. 8, the electrode plate group 1 for accommodating in the circular outer case is such that the positive electrode plate 7 and the negative electrode plate 8 are formed in an arc in the width direction so as to correspond to the circular accommodating space. By cutting out from the positive electrode plate material and the negative electrode plate material, respectively, the electrode plate group 1 having a good space efficiency can be formed. The positive electrode plate 7 is a connecting piece 1 that connects the positive electrode stacking surfaces 17a to 17e.
9a to 19d are formed so that the lengthwise dimension thereof is gradually increased, and the negative electrode plate 8 is formed such that the lengthwise dimension of the connecting pieces 20a to 20d for connecting the negative electrode stacking surfaces 18a to 18e is gradually increased. Thus, the positive electrode stacking surfaces 17a to 17
e and the negative electrode stacking surfaces 18a to 18e can be wound flat so as to be stacked via the separator 9.

[0009]

For example, the positive electrode plate 7 is
As shown in FIG. 9, a positive electrode plate material 50 having positive electrode active material layers 52 formed on both surfaces of a positive electrode current collector 51 made of aluminum foil or the like is continuously cut into a predetermined shape as shown in the figure. The same applies to the case of the negative electrode plate 8, which is cut out into a predetermined shape shown in FIG. 8B from the negative electrode plate material in which the negative electrode active material is coated on both surfaces of the negative electrode current collector formed of copper foil or the like. The positive electrode lead 15 is attached to one end of the positive electrode plate 7, and the negative electrode plate 8 is attached.
It is necessary to form the negative electrode lead 16 at one end. The positive electrode lead 15 needs to have a positive electrode current collector exposed for electrical connection by welding, and the negative electrode lead 16 needs to have a negative electrode current collector exposed as well. That is, the positive electrode plate 7 provided with the positive electrode lead 15 is, as shown in FIG. 9, a positive electrode plate material 50 in which a positive electrode current collector 51 has a positive electrode active material layer 52 formed portion and an uncoated portion formed. It is necessary to cut out from. Similarly, the negative electrode plate 8 provided with the negative electrode lead 16 also needs to be cut out from the negative electrode plate material in which the negative electrode current collector is coated with the negative electrode active material and the non-coated portion. Therefore, the positive electrode plate material and the negative electrode plate material are inefficient manufacturing processes for forming a portion where the positive electrode active material layer or the negative electrode active material layer is formed and a portion where the positive electrode active material layer is not formed, depending on the structures of the positive electrode plate 7 and the negative electrode plate 8. There was a point.

Further, when the positive electrode plate 7 is cut out from the positive electrode plate material and the negative electrode plate 8 is cut out from the negative electrode plate material, as shown in FIG. 9, the portion where the positive electrode lead 15 and the negative electrode lead 16 are formed is left after being cut out. The amount of residue was large, and there was a waste of increasing the amount of material resources discarded.

Further, the positive electrode lead 15 and the negative electrode lead 16
As shown in FIG. 7, since it is bent during welding and assembling to the case, it is necessary to use a material having high flexibility, but since it is formed integrally with the positive electrode plate 7, The material of the electric body, for example, the aluminum foil as it is is used as the positive electrode lead 15. The aluminum foil used as the positive electrode current collector has a thickness of usually 20 μm, has low mechanical strength, and may be broken due to the force of drawing and folding.

The object of the present invention is to separately form the leads drawn from the positive electrode plate and / or the negative electrode plate to reduce the number of manufacturing steps of the electrode plate material, reduce the amount of residue, the lead material and the treatment method. It is an object of the present invention to provide a flat battery which realizes selectivity, facilitates the manufacture of a flat battery using a wound electrode group, and reduces the cost, and a manufacturing method thereof.

[0013]

In order to achieve the above object, the first invention of the present application provides a positive electrode plate having a positive electrode active material layer formed on a positive electrode current collector and a negative electrode active material layer on a negative electrode current collector. The formed negative electrode plate is formed in a strip shape, respectively, and the positive electrode plate and the negative electrode plate are flatly wound from the other end side through a separator to form an electrode plate group, and a cap formed in a half shell body is formed. The electrode plate group is housed in an internal space formed by combining a case and a sealing case with their openings facing each other and placing a gasket between their side peripheral portions, and provided at one end of the positive electrode plate. A flat battery in which a negative electrode lead provided at one end of a positive electrode lead and a negative electrode plate is divided and welded to a cap case or a sealing case, and the positive electrode lead and / or the negative electrode lead is a positive electrode plate or a negative electrode plate. It is formed as a separate body, and the positive electrode plate or Characterized by comprising welded connected to one end of the electrode plate.

According to the above construction, the positive electrode lead or the negative electrode lead, which connects the positive electrode plate and the negative electrode plate separately to the cap case or the sealing case, is formed separately from the electrode plate. Etc. can be freely selected. The lead can be subjected to heat treatment or the like suitable for durability and handling by using an optimum material according to the assembling method and characteristics of the battery. Further, since the lead portion is a separate body, the loss portion when cutting the electrode plate from the material is small, and it is possible to reduce the amount of residue and prevent unnecessary cost increase. Therefore, it is possible to manufacture the flat battery using the electrode group having the winding structure with good quality, and to reduce the cost.

In the flat battery having the above structure, a current collector exposed portion where no active material layer is present is formed at one end of the positive electrode plate and / or the negative electrode plate, and the positive electrode lead or the negative electrode lead is formed on the current collector exposed portion. It can be configured to weld.
The positive electrode current collector exposed portion and the negative electrode current collector exposed portion are easily formed by providing a portion where the active material layer is not formed in the electrode plate material or by a process of peeling and removing the active material layer at a required portion. be able to.

By forming the lead separately from the electrode plate, the positive electrode current collector and the positive electrode lead can be made of different materials, or the negative electrode current collector and the negative electrode lead can be made of different materials. The lead made of the most suitable material can be used.

The method for manufacturing a flat battery according to the second aspect of the present invention is a positive electrode plate material having a positive electrode active material layer formed on a positive electrode current collector and a negative electrode plate material having a negative electrode active material layer formed on a negative electrode current collector. From this, a current collector exposed portion or lead is formed at one end, and the positive electrode plate and the negative electrode plate are respectively cut into strips, and the positive electrode lead material and the material and material thickness depending on the characteristics of the flat battery, and the treatment method are selected. A positive electrode lead and / or a negative electrode lead having a predetermined size is cut out from the negative electrode lead material, and one end of the positive electrode lead or the negative electrode lead is provided on the current collector exposed part of the positive electrode plate or the negative electrode plate on which the current collector exposed part is formed. Weld the
A positive electrode plate and a negative electrode plate, one end side of each end of the winding is placed a separator between both electrode plates to form an electrode plate group by flatly winding, and a cap case and a sealing case formed in a half shell. The electrode plate group is housed in the internal space formed by, and the positive electrode lead and the negative electrode lead are distributed and welded to a cap case or a sealing case, and the cap case and the sealing case are made to face each other with their openings facing each other. A gasket is arranged between the side peripheral portions of the cap case and the cap case and the cap case is sealed.

According to the above-described method for manufacturing a flat battery, the electrode plate and the lead can be separately manufactured and welded to each other, so that the material and processing method of the electrode plate and the lead can be freely selected. be able to. The lead can be subjected to heat treatment or the like suitable for durability and handling by using an optimum material according to the assembling method and characteristics of the battery. In addition, since the lead portion is a separate body, there is little loss when cutting the electrode plate and the lead from the material, and it is possible to reduce the amount of residue and prevent unnecessary cost increases. Therefore, it is possible to manufacture the flat battery using the electrode group having the winding structure with good quality, and to reduce the cost.

The lead welding portion of the electrode plate in the above manufacturing method is formed by providing a current collector exposed portion where the active material is not partially coated on the current collector, and one end side is located at the current collector exposed portion. A method of cutting out the positive electrode plate and / or the negative electrode plate, or after coating the current collector with the active material, an active material layer at a predetermined portion is peeled off to provide a current collector exposed portion, and one end side is exposed to the current collector. It is possible to apply a method of cutting out the positive electrode plate and / or the negative electrode plate so as to be located in the portion.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiments described below are examples of embodying the present invention and do not limit the technical scope of the present invention.

The flat battery according to the present embodiment shows an example configured as a circular coin-shaped lithium ion secondary battery, and elements common to the conventional configuration are designated by the same reference numerals. As shown in FIG. 1 as a cross-sectional view, a cap case 4 and a sealing case 5 formed in a circular half-shell are sealed and joined together by a gasket 6, and a positive electrode plate and a negative electrode plate are interposed by a separator. This is a flat battery having a high load current characteristic, which accommodates the wound electrode plate group 10 having a wound structure.

As shown in FIG. 4 (a), the electrode group 10 has a positive electrode plate 11 having a positive electrode lead 13 welded and connected at one end at a welding point (C), and as shown in FIG. 4 (b). , The negative electrode plate 1 having the negative electrode lead 14 welded to one end at the welding point (D)
2 and 2 are flatly wound with a separator 9 interposed therebetween.

As shown in FIG. 2 (a), the positive electrode plate 11 has a plurality of positive electrode laminated surfaces 22a at a portion where a positive electrode active material layer (hatched portion) is formed on the positive electrode current collector of the positive electrode plate material. ~ 2
2d is connected by the positive electrode connecting pieces 24a to 24d to form an electrode plate portion, and the positive electrode lead welding portion 26 exposing the positive electrode current collector is provided at one end thereof. The positive electrode plate material for forming the positive electrode plate 11 is, for example, on both surfaces of a positive electrode current collector formed of an aluminum foil having a thickness of 20 μm.
A positive electrode active material layer is formed to a predetermined thickness by applying a paste prepared by kneading and dispersing a positive electrode active material, a binder and the like in a solvent, and drying and rolling the paste. The positive electrode lead welding portion 26 provided at one end of the positive electrode plate 11 is provided with a positive electrode current collector exposed portion that is not partially coated with the paste in the step of manufacturing the positive electrode plate material. It can be formed by punching out the positive electrode plate 11 so that the positive electrode lead welded portion 26 is located at. Further, the positive electrode active material layer is partially peeled from the positive electrode plate material in which the positive electrode active material layer is formed on the entire surface of the positive electrode current collector, and the peeled material is removed to form the positive electrode current collector exposed portion. It can also be formed by punching out the positive electrode plate 11 so that the positive electrode lead welded portion 26 is located at the exposed portion of the electric body. The positive electrode active material layer may be peeled off by applying a method in which a chip that is ultrasonically excited is pressed against the peeling site, a method in which a heated hot plate is pressed in, a method that applies a solvent that dissolves the active material layer, The positive electrode current collector can be partially exposed by removing the peeled active material layer with a metal brush or a scraping plate.

As shown in FIG. 2 (b), the negative electrode plate 12 has a plurality of negative electrode laminates at the site where the negative electrode active material layer (hatched portion) is formed on the negative electrode current collector of the negative electrode plate material. Face 23
a to 23e are connected by negative electrode connecting pieces 25a to 25d to form an electrode plate portion, and a negative electrode lead welding portion 27 exposing the negative electrode current collector is provided at one end thereof. This negative electrode plate 1
The negative electrode plate material for forming 2 has, for example, a thickness of 20 μm.
The negative electrode current collector formed by the copper foil of m is coated with a paste prepared by kneading and dispersing a carbon material, a binder and the like in a solvent, and dried and rolled to form a negative electrode active material layer with a predetermined thickness. It was formed. The negative electrode lead welded portion 27 provided at one end of the negative electrode plate 12 is provided with a negative electrode current collector exposed portion where a negative electrode active material layer is not partially formed in the step of manufacturing the negative electrode plate material, and the negative electrode current collector exposed portion. Negative electrode lead welding part 2
It can be formed by punching out the negative electrode plate 11 so that 7 is located. In addition, the negative electrode active material layer is partially peeled from the negative electrode plate material in which the negative electrode active material layer is formed on the entire surface of the negative electrode current collector, and the peeled material is removed to form an exposed portion of the negative electrode current collector. It can also be formed by punching out the negative electrode plate 12 so that the negative electrode lead welding portion 27 is located at the exposed portion of the electric body. The peeling and removal of the negative electrode active material layer can be performed by the same method as in the case of the positive electrode active material layer.

Further, the positive electrode lead 13 is cut out from the positive electrode lead material into a predetermined width and length as shown in FIG. 3 (a). The positive electrode lead material has a thickness of 20 μm, for example.
It is preferable that the aluminum foil of (1) is heat-treated (annealed) to give flexibility. Further, the negative electrode lead 14 is cut out from the negative electrode lead material into a predetermined width and length as shown in FIG. As the negative electrode lead material, a copper foil having a thickness of 20 μm, which is the same as the material of the negative electrode current collector of the negative electrode plate 12, may be applied, but a nickel foil may also be applied.

As shown in FIG. 4A, one end of the positive electrode lead 13 is welded to the positive electrode lead welding portion 26 provided at one end of the positive electrode plate 11. Since welding is performed by joining aluminum foils together, there is a problem that holes are opened before welding by a welding method such as resistance welding, and ultrasonic welding is preferable. Since ultrasonic welding applies ultrasonic vibration to the joint interface,
Even in the case of a material such as aluminum where an oxide film is likely to form on the surface, the oxide film is destroyed by friction due to vibration and at the same time plastic deformation occurs and adhesion between new metal surfaces is achieved, and local temperature rise due to friction heat causes Atom diffusion and recrystallization are promoted, and a strong bonded state is obtained. In addition, the negative electrode lead welding portion 2 provided at one end of the negative electrode plate 12
As shown in FIG. 4B, one end of the negative electrode lead 14 is welded to 7. Since welding is joining between copper foil-copper foil or copper foil-nickel foil, ultrasonic welding, resistance welding, or laser welding can be applied.

Positive electrode plate 11 to which positive electrode lead 13 is welded
And the negative electrode plate 12 to which the negative electrode lead 14 is welded, and the positive electrode laminated surfaces 22a to 22d and the negative electrode laminated surfaces 23a to 23d are disposed with the separator 9 interposed between the both electrode plates with one end side joined to the lead being the winding end. It is wound flat so as to be alternately laminated and formed into the electrode plate group 10.

FIG. 5 is a plan view showing a state in which the electrode plate group 10 is housed in the sealing case 5, and the electrode plate group 10 has little wasted space in the circular space formed by the sealing case 5. It is formed in a planar shape and is housed in the sealing case 5 in a space-efficient state.

Negative electrode lead 1 pulled out from the electrode plate group 10.
As shown in FIG. 1, 4 is welded to the welding point (B) on the inner surface of the sealing case 5. Further, the positive electrode lead 13 drawn out from the electrode plate group 10 is welded to the inner surface of the cap case 4 as shown in FIG. For welding, the other end of the positive electrode lead 13 is positioned on the inner surface of the cap case 4, and the positive electrode lead 13 is ultrasonically welded to the welding point (A) of the cap case 4. By this lead connection by welding, it is possible to cope with a large discharge current obtained by the electrode group 10 having a wound structure.

A resin gasket 6 is attached to the side surface of the sealing case 5, and a predetermined amount of electrolytic solution is injected into the sealing case 5. After a waiting time until the electrode plate group 1a is impregnated with this electrolytic solution, the cap case 4 is covered on the sealing case 5, and the opening end side of the side peripheral surface of the cap case 4 is covered from the surroundings. By the crimping process of bending to the side, the gasket 6 is compressed on the step formed on the side peripheral surface of the sealing case 5, and the gap between the sealing case 5 and the cap case 4 is sealed, and the flat battery as shown in FIG. Is completed.

When the positive electrode lead 13 is laid around when welding the positive electrode lead 13 to the cap case 4, or when the positive electrode lead 13 that extends long when the cap case 4 is put on the sealing case 5 is folded on the electrode plate group 10, the positive electrode The lead 13 is easily broken, but the occurrence of breakage is suppressed by using the positive electrode lead material whose flexibility is improved by annealing as described above. When the conventional positive electrode current collector is extended, the degree of breakage is increased due to lack of flexibility. However, as in the present embodiment, the positive electrode plate 11 and the positive electrode lead 13 are separately provided, and the material and By allowing the treatment method to be arbitrarily selected, a flat battery of higher quality can be constructed.

In the embodiment described above, the positive electrode lead 13 and the negative electrode lead 1 are provided on the positive electrode plate 11 and the negative electrode plate 12, respectively.
Although 4 is welded and connected, lead connection can be applied to only one of the positive electrode plate 11 and the negative electrode plate 12. In the case of the negative electrode plate 12, since the strength of the copper foil which is the material of the negative electrode current collector is high, the negative electrode plate 12 and the negative electrode lead 14 are integrally formed, and only the positive electrode plate 11 is annealed to have flexibility. Alternatively, the positive electrode lead 13 may be connected by welding.

[0033]

As described above, according to the present invention, since the lead is welded and connected to the positive electrode plate and / or the negative electrode plate, the electrode plate and the lead can be formed separately. It is possible to freely select each material, processing method and the like. The lead can be subjected to heat treatment or the like suitable for durability and handling by using an optimum material according to the assembling method and characteristics of the battery. Further, by forming the lead portion as a separate body, a loss portion when cutting the electrode plate from the material is small, and it is possible to reduce the amount of residue and prevent unnecessary cost increase. Therefore, it is possible to manufacture the flat battery using the electrode group having the winding structure with good quality, and to reduce the cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a flat battery according to an embodiment.

FIG. 2 is a development view of a positive electrode plate (a) and a negative electrode plate (b).

FIG. 3 is a plan view of a positive electrode lead (a) and a negative electrode lead (b).

FIG. 4 is a plan view showing a state in which a positive electrode lead and a negative electrode lead are welded and connected to a positive electrode plate (a) and a negative electrode plate (b), respectively.

FIG. 5 is a plan view showing a state in which an electrode group is housed in a sealing case.

FIG. 6 is a cross-sectional view of a conventional flat battery.

FIG. 7 is a cross-sectional view of a flat battery using a wound electrode group according to the related art.

8A and 8B are development views showing the configuration of a positive electrode plate and a negative electrode plate, respectively, which constitute an electrode plate group.

FIG. 9 is an explanatory view showing a state in which a positive electrode plate is cut out from a positive electrode plate material.

[Explanation of symbols]

4 cap case 5 sealing case 6 gasket 10 electrode group 11 Positive electrode plate 12 Negative electrode plate 13 Positive electrode lead 14 Negative electrode lead 26 Positive electrode lead welding part (exposed part of positive electrode current collector) 27 Negative electrode lead welding part (exposed part of negative electrode current collector)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Ogawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5H022 AA09 AA18 BB03 BB17 BB21                       CC08 CC12 CC16 CC21                 5H028 AA07 BB01 BB05 BB07 CC02                       CC05 CC12 CC24                 5H029 AJ14 BJ03 BJ14 CJ04 CJ05                       CJ07 CJ28 DJ05 DJ07 HJ12                 5H050 AA19 BA17 DA20 FA05 GA02                       GA03 GA04 GA07 GA09 GA10                       GA22 HA12

Claims (6)

[Claims] 1. A positive electrode plate in which a positive electrode active material layer is formed on a positive electrode current collector and a negative electrode plate in which a negative electrode active material layer is formed on a negative electrode current collector are respectively formed in strips, and the positive electrode plate and the negative electrode are formed. A plate and a plate group are formed by flatly winding from the other end side through a separator to form an electrode plate group. The electrode plate group is housed in an internal space formed by arranging a gasket between the peripheral portions, and a positive electrode lead provided at one end of the positive electrode plate and a negative electrode lead provided at one end of the negative electrode plate are cap cases or A flat battery, which is divided into a sealing case and weld-connected to each other, wherein the positive electrode lead and / or
Alternatively, the flat battery is characterized in that the negative electrode lead is formed separately from the positive electrode plate or the negative electrode plate, and is welded and connected to one end of the positive electrode plate or the negative electrode plate. 2. The positive electrode plate and / or the negative electrode plate is provided with a current collector exposed portion where an active material layer does not exist at one end, and the positive electrode lead or the negative electrode lead is welded to the current collector exposed portion. The flat battery described in. 3. The flat battery according to claim 1, wherein the materials of the positive electrode current collector and the positive electrode lead and the materials of the negative electrode current collector and the negative electrode lead are different from each other. 4. A current collector exposed portion or a lead is provided at one end from a positive electrode plate material having a positive electrode active material layer formed on a positive electrode current collector and a negative electrode plate material having a negative electrode active material layer formed on a negative electrode current collector. A positive electrode plate and a negative electrode plate are formed and cut into strips, and the positive electrode and / or the negative electrode lead material of which the material and material thickness and the treatment method are selected according to the characteristics of the flat battery are each a predetermined size of positive electrode. Cutting out the lead and / or the negative electrode lead, by welding one end of the positive electrode lead or the negative electrode lead to the current collector exposed part of the positive electrode plate or the negative electrode plate on which the current collector exposed part is formed, the positive electrode plate and the negative electrode plate, Each end is wound at the end, and a separator is placed between both plates to form a plate group by flatly winding, and inside the inner space formed by the cap case and sealing case formed in the half shell. Accommodating the electrode plate group, The pole lead and the negative lead are distributed and welded to the cap case or the sealing case, the openings of the cap case and the sealing case are opposed to each other, a gasket is arranged between the side peripheral portions of the cap case and the sealing case, and the cap case and the sealing case are sealed. A method for manufacturing a flat battery, characterized in that a gap between the case and the case is sealed. 5. The current collector is provided with a current collector exposed portion that is not partially coated with the active material, and the positive electrode plate and / or the negative electrode plate is cut out so that one end side is located in the current collector exposed portion. 4. The method for manufacturing a flat battery according to item 4. 6. The positive electrode plate is provided with a current collector exposed portion obtained by peeling off the active material layer at a predetermined portion after coating the current collector with the active material, and one end side of which is positioned at the current collector exposed portion. And / or the negative electrode plate is cut out, and the method for producing a flat battery according to claim 4.