JP2009224102A - Flat battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat battery capable of facilitating positioning of the negative active material layer of a negative electrode and the positive active material layer of a positive electrode in an electrode body formed by laminating a plurality of sets of a positive electrode, a negative electrode, and a separator placed between both electrodes in the up and down direction. <P>SOLUTION: The flat battery is formed by housing the electrode body 1 formed by laminating a plurality of sets of the positive electrode 4, the negative electrode 5, and the separator 6 placed between booth electrodes in the up and down direction in an outer packaging 2 made of a laminate film 3. In the negative electrode 5, a negative active material layer 10 is arranged on up and down both sides of the negative electrode 5 by arranging a metallic lithium negative active material layer 10 on one surface of a sheet-like negative current collector 11, and folding the negative current collector 11 up and down so that the other surface, where the negative active material layer 10 is not arranged, of the negative current collector 11 is positioned on the inside. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flat battery such as a lithium primary battery in which an electrode body as a power generation element is accommodated in a bag-shaped exterior member made of a laminate film in order to liberalize the battery posture, such as bending the battery. .

  For example, Patent Documents 1 to 3 can be cited as well-known examples of a flat battery in which an electrode body is accommodated in a bag-shaped exterior material made of a laminate film. In the flat battery of Patent Document 1, an electrode body is formed by stacking a sheet-like positive electrode, a sheet-like separator, and a sheet-like negative electrode on top and bottom, and the electrode body is placed in a bag-like exterior material made of a laminate film. Contained.

  In the flat battery of Patent Document 2, the positive electrode is bent so that the positive electrode active material layers formed on one surface of the positive electrode current collector face each other, and a separator is interposed between the surfaces where the positive electrode active material layers face each other. An electrode body is formed by arranging a negative electrode in a bent posture, and the electrode body is accommodated in a bag-shaped exterior material made of a laminate film. In the flat battery of Patent Document 3, the separator is folded in half to sandwich the positive electrode, and a plurality of positive electrodes and negative electrodes sandwiched between the separators are alternately stacked to form an electrode body. It is housed in a bag-like exterior material.

Japanese Patent Laid-Open No. 11-31505 (FIG. 3-4) Japanese Patent Laying-Open No. 2007-42567 (FIG. 2) JP 2008-41623 A (FIG. 1)

  However, in the flat battery of Patent Document 1, since only one positive electrode and one negative electrode are stacked as shown in FIG. 4, the facing area between the positive electrode and the negative electrode is not so large. Only the discharge current cannot be increased. In the flat battery of Patent Document 2, since the positive electrode and the negative electrode overlap each other in a plurality of stages as shown in FIG. 2, the facing area between the positive electrode and the negative electrode can be increased and the discharge current can be increased. It is not easy to dispose the positive electrode active material layer on the positive electrode current collector so that the positive electrode active material layer is in the correct facing position in the state of being made. For this reason, in the flat battery of Patent Document 2, the positive electrode active material layer is likely to be displaced from an appropriate facing position, and the discharge current may not be sufficiently increased.

  The flat battery of Patent Document 3 also has an advantage that the discharge current can be increased by stacking a plurality of positive electrodes and negative electrodes. By the way, in such a flat battery, the negative electrode positioned between the upper and lower positive electrodes is formed, for example, by disposing negative electrode active material layers on both upper and lower surfaces of the negative electrode current collector. Since the step of disposing the negative electrode active material layer on the upper surface of the body and the step of disposing the negative electrode active material layer on the lower surface of the negative electrode current collector are performed separately, the positional relationship between the upper and lower negative electrode active material layers due to manufacturing errors May shift.

  For this reason, when trying to make the negative electrode active material layers on the upper and lower sides of the negative electrode current collector accurately face the positive electrode active material layers of the positive electrode stacked on the upper and lower sides of the negative electrode, respectively, For each layer, it is necessary to align the positive electrode active material layer of each positive electrode that overlaps the negative electrode. Therefore, it takes time and effort to produce the electrode body.

  The present invention has been made in order to solve the above-described problems, and in an electrode body in which a plurality of positive electrodes, negative electrodes, and separators are stacked in the vertical direction, a negative electrode active material layer of the negative electrode and a positive electrode active material of the positive electrode It is an object of the present invention to provide a flat battery that can be easily aligned with a layer.

The present invention relates to a flat battery in which a plurality of electrode bodies 1 stacked in the vertical direction with a separator 6 interposed between a positive electrode 4 and a negative electrode 5 are accommodated in a bag-shaped exterior material 2 made of a laminate film 3. Is targeted. One electrode 5 of the positive electrode 4 and the negative electrode 5 has a metal active material layer 10 disposed on one surface of a sheet-like current collector 11 and the other one on which the active material layer 10 is not disposed. The active material layers 10 are arranged on both the upper and lower sides of one of the electrodes 5 by folding the current collector 11 up and down with the surface of the electrode 11 inside.
Here, one electrode is used as a negative electrode, and one electrode is provided with the sign of the negative electrode 5, but one electrode may be the positive electrode 4.

The separator 6 is formed in a flat rectangular bag shape, and the other electrode 4 of the positive electrode 4 and the negative electrode 5 can be accommodated in the bag-like separator 6.
Here, as described above, one electrode is a negative electrode, the other electrode is a positive electrode, and the other electrode is labeled with the positive electrode 4. However, the other electrode may be the negative electrode 5.

  Specifically, the separator 6 is formed into a flat rectangular bag shape by folding a single sheet material 12 up and down and bonding the peripheral edges of the upper portion 6a and the lower portion 6b of the separator 6 together. Has been.

  Further, the separator 6 can be formed into a flat rectangular bag shape by overlapping two sheet materials 12 and bonding the peripheral edges of these sheet materials 12 together.

  A conductive lead 19 may be integrally formed on the current collector 11 of one electrode 5.

  The other electrode 4 accommodated in the bag-like separator 6 is produced by arranging the active material layer 7 on the upper and lower surfaces of the sheet-like current collector 9, and the current collector 9 of the other electrode 4 is formed on the current collector 9. A conductive lead 15 is integrally formed, and the lead 15 is led out of the separator 6 from one side 17 of the four sides of the bag-like separator 6. A covering portion 20 for covering the base end side of the lead 15 of the other electrode 4 may be extended to one side 17 of the separator 6.

  In the flat battery of the present invention, one electrode 5 of the electrode body 1 has a metal active material layer 10 disposed on one surface of a current collector 11 and the other one on which the active material layer 10 is not disposed. The active material layers 10 are arranged on both the upper and lower sides of the electrode 5 by folding the current collector 11 up and down with the surface of the electrode 5 inward, so that, for example, the folding position of the active material layer 10 is set appropriately when folded. By managing to, the positional relationship between the upper and lower active material layers 10 of one electrode 5 can be accurately matched.

  In other words, in the present invention, the active material layer 10 of one electrode 5 is composed of a metal plate (or metal foil) that can obtain higher dimensional accuracy than the case where the active material is applied to the current collector 11 and formed. In addition, the active material layers 10a and 10b (see FIG. 5B) disposed above and below the one electrode 5 by being folded are respectively disposed on the same surface of the current collector 11 before being folded. The operation of arranging the active material layers 10a and 10b on the current collector 11 can be performed in the same process. Therefore, for example, the active material layers 10a and 10b are arranged more than when the step of disposing the active material layer 10a on the upper surface of the current collector 11 and the step of disposing the active material layer 10b on the lower surface of the current collector 11 are performed separately. The positional relationship between the two can be easily matched, and the displacement of the positional relationship between the active material layers 10a and 10b can be suppressed. Therefore, for example, the position of the lower active material layer 10b can be accurately grasped from the position of the upper active material layer 10a. Thus, for example, based on only the position of the upper active material layer 10a, even if the opposing positions of the active material layer 7 of the other electrode 4 overlapping above and below the one electrode 5 are matched, the lower active material The layer 10b also properly opposes the active material layer 7 of the other electrode 4 on the lower side.

  That is, according to the present invention, the trouble of matching the lower active material layer 10b of one electrode 5 with the position opposite to the active material layer 7 of the lower electrode 4 can be omitted. In this way, the present invention can reduce the trouble of aligning the facing positions of the active material layers 7 and 10 of the positive and negative electrodes 4 and 5, while making the positive electrode 4 and the negative electrode 5 properly face each other to ensure the discharge current. It can be enlarged. Here, in order to satisfactorily perform the alignment, it is preferable that the active material layers 10a and 10b are connected to each other. However, in order for the active material layer 10 to be appropriately bent at the fold portion of the current collector 11, The active material layer 10 may be cut at the crease portion of the current collector 11, and the active material layers 10 a and 10 b may be disposed apart from each other.

  When the other electrode 4 is accommodated in the flat rectangular bag-shaped separator 6, it is possible to reliably prevent the other electrode 4 from contacting the one electrode 5 and short-circuiting the positive electrode 4 and the negative electrode 5. . In addition, since the separator 6 and the other electrode 4 in the separator 6 can be stacked as a single unit, the electrode body 1 is formed in comparison with the case where the positive electrode 4, the negative electrode 5 and the separator 6 are stacked separately, for example. It can be produced efficiently. Thereby, the manufacturing efficiency of the flat battery is improved.

  Further, since the other electrode 4 is sandwiched between the upper and lower portions 6 a and 6 b of the flat rectangular bag-shaped separator 6, the other electrode 4 is difficult to move with respect to the separator 6. Therefore, the active material layers 7 and 10 of the positive and negative electrodes 4 and 5 can be properly opposed to each other only by positioning one electrode 5 with respect to the separator 6. That is, according to the present invention, the three electrodes are aligned while the other electrode 4, the one electrode 5, and the separator 6 are aligned by simply stacking them while aligning the one electrode 5 and the separator 6. Thereby, the manufacturing efficiency of the flat battery is improved.

  When the bag-like separator 6 is formed by folding a single sheet material 12 up and down and bonding the peripheral edges of the upper portion 6a and the lower portion 6b of the separator 6, Since it can form in a bag shape only by adhere | attaching the other 2 sides or three sides except the crease | fold 16, the labor for producing the bag-shaped separator 6 can be reduced by this amount.

  If the bag-like separator 6 is formed by stacking two sheet materials 12 and bonding the peripheral edges of these sheet materials 12, using a material that is not easy to fold, such as hard plastic, A bag-like separator 6 can be produced.

  If the lead 19 is integrally formed with the current collector 11 of one electrode 5, the current collector 11 and the lead 19 can be manufactured simultaneously. That is, for example, the manufacturing efficiency of the electrode body 1 is improved as compared with the case where the lead 19 is formed separately from the current collector 11 and the lead 19 is attached to the current collector 11. This improves the manufacturing efficiency of the flat rectangular battery.

  A lead 15 is formed integrally with the current collector 9 of the other electrode 4, the lead 15 is led out from one side 17 of the bag-like separator 6, and the base 15 of the lead 15 is covered with the one side 17 of the separator 6. If the covering portion 20 is extended, the current collector 9 and the lead 15 can be manufactured at the same time. This also improves the manufacturing efficiency of the electrode body 1 and increases the manufacturing efficiency of the flat rectangular battery. Will improve. Further, the covering portion 20 can surely prevent the lead 15 from coming into contact with one electrode 5 and short-circuiting. Accordingly, the yield of the flat battery is improved, and the manufacturing efficiency of the flat battery is improved.

  1 to 6 show a flat battery according to the present invention. As shown in FIG. 3, this flat battery accommodates the electrode body 1 of the power generation element and the non-aqueous electrolyte in a flat rectangular bag-shaped exterior member 2. The exterior material 2 is formed in a bag shape by thermally welding the peripheral edges of two rectangular laminate films 3 and 3. The laminate film 3 is formed, for example, by laminating a heat-fusible film, a metal foil, and a protective film in this order from the inner surface side. The heat-fusible film is made of a modified polyolefin film or the like, the metal foil is made of an aluminum foil or a stainless steel foil, and the protective film is made of a polyester film or the like. The thickness dimension of the laminate film 3 is about 100 μm. The flat battery according to the present invention has a vertical dimension of 30 mm and a horizontal dimension of 20 mm.

  As shown in FIG. 1, the electrode body 1 has a rectangular positive electrode 4 (see FIG. 4) and a square negative electrode 5 (see FIG. 5A) alternately in the vertical direction with a separator 6 interposed therebetween. A plurality of layers are stacked to form a rectangular parallelepiped shape. In FIG. 1, the positive electrode 4 has three layers and the negative electrode 5 has four layers. The positive electrode 4 is produced by disposing a positive electrode active material layer 7 containing a positive electrode active material such as manganese dioxide on the upper and lower surfaces of a sheet-like positive electrode current collector 9 made of a metal foil such as aluminum or stainless steel. . The thickness dimension of the positive electrode 4 is 150 μm.

  As shown in FIG. 1 and FIG. 5 (b), the negative electrode 5 has a sheet-like negative electrode active material layer 10 made of a metal plate such as metal lithium or an alloy of lithium and aluminum, and is made of a metal foil such as copper. The negative electrode current collector 11 is arranged on one surface of both the upper and lower surfaces of the negative electrode current collector 11 and the negative electrode current collector 11 is folded up and down with the other surface where the negative electrode active material layer 10 is not disposed inside. Thus, the negative electrode active material layers 10 are arranged on both the upper and lower sides of the negative electrode 5. The thickness dimension of the negative electrode active material layer 10 of the negative electrode 5 is 50 μm, and the thickness dimension of the negative electrode current collector 11 is 8 to 20 μm.

  In the uppermost negative electrode 5, the negative electrode current collector 11 is not folded, and the negative electrode active material layer 10 is disposed only on the lower surface side of the negative electrode current collector 11. Further, the negative electrode 5 in the lowermost stage also does not fold the negative electrode current collector 11, and the negative electrode active material layer 10 is disposed only on the upper surface side of the negative electrode current collector 11. Note that the negative electrode current collectors 11 of the uppermost and lowermost negative electrodes 5 are in contact with the heat-fusible film on the inner surface side of the outer packaging material 2 respectively. There is no short circuit with the metal foil of the material 2.

  The separator 6 is composed of a microporous thin film made of polyethylene, polypropylene or the like having excellent insulating properties, and is capable of transmitting lithium ions. That is, as shown in FIG. 4, the separator 6 is formed by folding a sheet material 12 of a rectangular microporous thin film vertically so as to sandwich the positive electrode 4, and the upper portion 6 a and the lower side of the separator 6. A flat rectangular bag shape (see FIG. 6) is formed by bonding the peripheral edges of the portion 6b with each other by heat welding or the like. Thus, the positive electrode 4 is accommodated in the flat rectangular bag-shaped separator 6. The vertical and horizontal dimensions of the bag-like separator 6 are larger than the vertical and horizontal dimensions of the positive electrode 4. The thickness dimension of the sheet material 12 is 16 μm.

  As shown in FIGS. 1 and 6, a conductive positive electrode lead 15 extending in the lateral direction is integrally formed on the positive electrode current collector 9 of each positive electrode 4. The positive electrode lead 15 is led out of the separator 6 from one side 17 located on the opposite side of the fold 16 of the sheet material 12 in the separator 6. As shown in FIGS. 2 and 6, a conductive negative electrode lead 19 extending in the lateral direction is integrally formed on the negative electrode current collector 11 of each negative electrode 5.

  As shown in FIGS. 4 and 6, a covering portion 20 for covering the proximal end side of the positive electrode lead 15 is extended to one side 17 of the separator 6. That is, the upper covering portion 20a and the lower covering portion 20b extend on one side 17 of the upper portion 6a and the lower portion 6b of the separator 6, respectively. The end side is sandwiched and covered from above and below (see FIG. 1). As shown in FIG. 1, the positive electrode lead 15 of each positive electrode 4 is connected to the base end portion of the positive electrode tab 21 by ultrasonic welding or the like in a state where the distal end side is put together. The positive electrode tab 21 is made of a clad material of aluminum and nickel, and the leading end side of the positive electrode tab 21 is led out from one side 22 of the exterior material 2 as shown in FIG.

  As shown in FIG. 2, the negative electrode lead 19 of each negative electrode 5 is connected to the base end portion of the negative electrode tab 23 by ultrasonic welding or the like in a state where the distal end side is put together. The negative electrode tab 23 is made of a clad material of copper and nickel, and the leading end side of the negative electrode tab 23 is led out from one side 22 of the exterior material 2 as shown in FIG.

  Each of the negative electrode active material layers 10 in the vertical and horizontal directions is configured so that the negative electrode active material layer 10 of the negative electrode 5 faces the positive electrode active material layer 7 of the positive electrode 4 and the short circuit due to misalignment during lamination can be prevented. The dimension is larger than each dimension of the positive electrode active material layer 7 in the vertical and horizontal directions. Furthermore, the vertical and horizontal dimensions of the negative electrode active material layer 10 are greater than the vertical and horizontal dimensions of the bag-like separator 6. Thus, when the negative electrode 5 covers the entire upper or lower surface of the separator 6, the negative electrode active material layer 10 of the negative electrode 5 is reliably attached to the positive electrode active material layer 7 of the positive electrode 4 in the separator 6. You will face each other.

  The assembly of the flat battery of the present invention will be described with reference to FIGS. As shown in FIG. 6, between the uppermost negative electrode 5 and the lowermost negative electrode 5, a plurality of bag-like separators 6 containing positive electrodes 4 and negative electrodes 5 are alternately stacked. Next, in a state where the leading ends of the positive electrode leads 15 of each positive electrode 4 are bundled together, they are connected to the positive electrode tab 21 by ultrasonic welding or the like. In addition, in a state where the leading ends of the negative electrode leads 26 of each negative electrode 5 are bundled together, they are connected to the negative electrode tab 23 by ultrasonic welding or the like.

  Then, the two laminated films 3 and 3 are stacked one above the other so as to sandwich the electrode body 1, and the upper and lower laminated films 3 constituting one side 22 of the exterior material 2 among the four sides of the upper and lower laminated films 3 and 3. -The positive electrode tab 21 and the negative electrode tab 23 are sandwiched on each side of 3. In this state, the upper and lower laminating films 3 and 3 are heat-welded on three sides including one side of the laminating film 3 and 3 constituting one side 22 of the exterior material 2. Thus, the positive electrode tab 21 and the negative electrode tab 23 are fixed to one side 22 of the exterior material 2.

Next, after injecting a non-aqueous electrolyte from the remaining one side of the upper and lower laminated films 3 and 3 that are not thermally welded, the remaining one side of the laminated films 3 and 3 is thermally welded. Thereby, the bag-shaped exterior material 2 is sealed. This completes the assembly of the flat battery of the present invention shown in FIG. The non-aqueous electrolyte was prepared, for example, by dissolving LiCF ₃ SO ₃ in a solvent in which propylene carbonate and dimethoxyethane were mixed.

  Thus, the negative electrode 5 of the electrode body 1 has the negative electrode active material layer 10 connected to the upper and lower sides of the negative electrode 5 by folding the negative electrode current collector 11 and the negative electrode active material layer 10 up and down. For this reason, the positional relationship of the upper and lower negative electrode active material layers 10 of the negative electrode 5 can be accurately matched by appropriately managing the positions of the folds of the negative electrode active material layer 10 during folding. That is, as shown in FIG. 5B, the negative electrode active material layers 10a and 10b that are arranged one above the other by being folded are arranged on the same surface of the negative electrode current collector 11 before being folded. The operation of disposing the negative electrode active material layers 10a and 10b on the current collector 11 can be performed in the same process. Therefore, for example, the negative electrode active material is more than the case where the step of disposing the negative electrode active material layer 10a on the upper surface of the negative electrode current collector 11 and the step of disposing the negative electrode active material layer 10b on the lower surface of the current collector 11 are performed separately. The positional relationship between the layers 10a and 10b can be easily matched, and deviation of the positional relationship between the negative electrode active material layers 10a and 10b can be suppressed. Therefore, the position of the lower negative electrode active material layer 10b can be accurately grasped from the position of the upper negative electrode active material layer 10a. Thus, for example, based on only the position of the upper negative electrode active material layer 10a, even if the opposing positions of the positive electrode active material layer 7 of the positive electrode 4 overlapping above and below the negative electrode 5 are matched, the lower negative electrode active material layer 10b also properly faces the positive electrode active material layer 7 of the lower positive electrode 4. That is, according to the present invention, it is possible to omit the trouble of matching the lower negative electrode active material layer 10b of the negative electrode 5 with the position opposite to the active material layer 7 of the other electrode 4 on the lower side.

  Moreover, since the positive electrode 4 is accommodated in the bag-shaped separator 6, it can prevent reliably that the positive electrode 4 contacts the negative electrode 5 and the positive electrode 4 and the negative electrode 5 are short-circuited. Since the positive electrode 4 is sandwiched between the upper and lower portions 6 a and 6 b of the flat bag-shaped separator 6, the positive electrode 4 is difficult to move with respect to the separator 6. Therefore, the positional relationship between the separator 6 and the positive electrode 4 can be specified. For this reason, for example, by making the vertical and horizontal dimensions of the bag-shaped separator 6 equal to the vertical and horizontal dimensions of the negative electrode 5, only alignment between the separator 6 and the negative electrode 5 is performed. The positive electrode 4 and the negative electrode 5 can be appropriately opposed to each other.

  Since the electrode body 1 is formed by laminating a plurality of the positive electrodes 4 and the negative electrodes 5 in the vertical direction, the facing area between the positive electrodes 4 and the negative electrodes 5 is increased, and the discharge current can be increased accordingly. Since the electrode body 1 is accommodated in the exterior material 2 made of the laminate film 3, it is possible to achieve liberalization of the battery posture such as bending the flat battery.

  The positive electrode lead 15 may be led out of the separator 6 from one of the other two sides excluding the fold 16 of the sheet material 12 and the one side 17 in the separator 6. The separator 6 may be formed in a flat rectangular bag shape by, for example, stacking two sheet materials 12 and bonding the peripheral edges of these sheet materials 12 together. In addition, a flat rectangular frame having a slightly larger thickness and vertical and horizontal dimensions than the thickness and vertical and horizontal dimensions of the positive electrode 4 is provided, and the positive electrode 4 is accommodated in the frame. The sheet material 12 may be bonded to the upper and lower surfaces of the frame to form the flat rectangular bag-shaped separator 6. The frame is made of an insulating resin or the like.

  The positive electrode lead 15 and the negative electrode lead 19 may be formed separately from the positive electrode 4 and the negative electrode 5, and the positive electrode lead 15 and the negative electrode lead 19 may be welded to the positive electrode 4 and the negative electrode 5, respectively. Instead of the covering portion 20 of the separator 6, the base end side of the positive electrode lead 15 of the positive electrode 4 may be covered with an insulating tape.

It is the sectional view on the AA line of FIG. 3 which shows the flat battery which concerns on this invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a perspective view of the flat battery of the present invention. It is a perspective view for demonstrating preparation of the separator which concerns on this invention. (A) is a perspective view of the negative electrode which concerns on this invention, (b) is a side view of a negative electrode. It is a perspective view for demonstrating the assembly of the electrode body which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode body 2 Exterior material 3 Laminate film 4 Positive electrode 5 Negative electrode 6 Separator 6a Upper part 6b Lower part 7 Positive electrode active material layer 9 Positive electrode current collector 10 Negative electrode active material layer 11 Negative electrode current collector 12 Sheet material 15 Positive electrode lead 17 One side Side 19 Negative electrode lead 20 Covering part

Claims (6)

A flat battery in which a plurality of vertically stacked electrode bodies with a separator interposed between a positive electrode and a negative electrode are housed in a bag-shaped exterior material made of a laminate film,
One electrode of the positive electrode and the negative electrode has a metal active material layer disposed on one surface of a sheet-like current collector, and the other surface on which the active material layer is not disposed is on the inside. The flat battery is characterized in that the current collector is folded up and down so that the active material layers are respectively disposed on the upper and lower sides of the one electrode.   The flat battery according to claim 1, wherein the separator is formed in a flat rectangular bag shape, and the other electrode of the positive electrode and the negative electrode is accommodated in the bag-shaped separator.   3. The flat shape according to claim 2, wherein the separator is formed in a flat rectangular bag shape by folding one sheet material up and down and bonding the peripheral edges of the upper portion and the lower portion of the separator. Type battery.   The flat battery according to claim 2, wherein the separator is formed into a flat rectangular bag shape by overlapping two sheet materials and bonding the peripheral edges of the sheet materials.   The flat battery according to any one of claims 1 to 4, wherein a conductive lead is integrally formed on the current collector of the one electrode. The other electrode housed in the bag-shaped separator is produced by disposing an active material layer on the upper and lower surfaces of a sheet-shaped current collector,
A conductive lead is integrally formed on the current collector of the other electrode, and the lead is led out of the separator from one of the four sides of the bag-shaped separator. ,
The flat battery according to any one of claims 2 to 5, wherein a covering portion for covering a base end side of the lead of the other electrode is extended on the one side of the separator.

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