JP6254647B2 - Flat battery - Google Patents

Description

  The present invention relates to a flat battery such as a coin battery.

A flat shape provided with a bottomed cylindrical outer can and a bottomed cylindrical sealing can disposed in an inverted dish shape with respect to the outer can so that a space is formed between the outer can and the outer can. Batteries are known. In such a flat battery, as disclosed in Patent Document 1, for example, an electrode configured by alternately laminating a plurality of positive electrodes and a plurality of negative electrodes in a space formed by an outer can and a sealed can. The body is stored.

In the above-described configuration, each of the plurality of positive electrodes and the plurality of negative electrodes includes a positive electrode tab (positive electrode connection portion) and a negative electrode tab (negative electrode connection portion). The positive electrode tabs and the negative electrode tabs are connected to each other. Thereby, the plurality of positive electrodes and the plurality of negative electrodes are electrically connected to each other.

JP 2009-289621 A

The positive electrode connecting portion and the negative electrode connecting portion connected to each other as described above are electrically connected to the outer can and the sealing can, respectively. For example, the positive electrode connection portion is connected to the outer can by welding, while the negative electrode connection portion is bent so as to contact the sealing can. Specifically, the negative electrode connecting portion is bent so that the tip portion is located between the end face of the electrode body and the sealing can.

Thus, in the case of a configuration in which the connecting portion is bent and the tip portion is positioned on the end face of the electrode body, the outer peripheral side of the electrode body may be partially pushed in the stacking direction by the connecting portion. If it does so, the clearance gap between the positive electrode and negative electrode which comprises an electrode body will become nonuniform in the part pressed by the bent connection part, and the part not pressed. In this case, the electrolyte does not easily enter the gap between the positive electrode and the negative electrode, and the intended battery performance may not be obtained.

Therefore, the object of the present invention is to prevent the gap between the positive electrode and the negative electrode constituting the electrode body from being varied by the positive electrode connecting portion that electrically connects the positive electrodes and the negative electrode connecting portion that electrically connects the negative electrodes. It is to obtain a configuration of a flat battery.

A flat battery according to an embodiment of the present invention has a bottomed cylindrical outer can that is disposed in an inverted dish shape with respect to the outer can so as to form a space between the outer can and the outer can. A cylindrical sealing can, and an electrode body housed in the space formed by combining the outer can and the sealing can, and the electrode body includes a plurality of flat plate layers that are alternately stacked. The positive electrode has a flat positive electrode body and a positive electrode connecting portion extending outward from the positive electrode body, and the negative electrode is external to the flat negative electrode body and the negative electrode body. The positive electrode main body and the negative electrode main body are stacked such that the positive electrode connection portions and the negative electrode connection portion protrude in different directions, and the positive electrode connection portions are stacked with each other. The positive electrode contacts are stacked alternately so that they are stacked together. And at least one of the negative electrode connecting portion and the negative electrode connecting portion are connected to each other so as to be bundled at the position of the central portion of the electrode body in the stacking direction, and the tip portion extends in the stacking direction of the electrode body. And it is bent so that it may not contact the said exterior can and the said sealing can (1st structure).

At least one of the positive electrode connecting portion and the negative electrode connecting portion is bent so that the tip portion extends in the stacking direction of the electrode body and does not contact the outer can and the sealing can. Therefore, it can prevent that said one connection part is located on the end surface of an electrode body. Thereby, it is possible to prevent variation in the gap between the positive electrode and the negative electrode constituting the electrode body due to the one connection portion. Therefore, it is possible to suppress variation in the infiltration property of the electrolytic solution with respect to the electrode body, and to prevent variation in battery performance.

And since the front-end | tip part of said one connection part does not contact an exterior can and a sealing can, even when the polarity of an exterior can and a sealing can differs from the polarity of said one connection part, A short circuit can be prevented from occurring between the outer can and the sealed can.

In the first configuration, among the positive electrode connection portion and the negative electrode connection portion, at least one connection portion bundled at the position of the central portion in the stacking direction of the electrode body is such that the electrode body is in the sealing can. It is preferably bent so as to extend toward the opening side of the sealing can in the arranged state (second configuration).

With the configuration described above, in the state where the electrode body is housed in the sealing can, at least one of the positive electrode connecting portion and the negative electrode connecting portion bundled at the position of the central portion in the stacking direction of the electrode body is a sealing can. It extends toward the opening side. Therefore, when storing the electrode body in the sealing can,
It can prevent that the front-end | tip part of said one connection part is caught on the inner surface of this sealing can. Therefore, with the above-described configuration, it is possible to improve workability when assembling the electrode body in the sealed can.

In the first or second configuration, the positive electrode connection portion and the negative electrode connection portion are respectively
The electrode bodies are connected to each other so as to be bundled at the position of the central portion in the stacking direction of the electrode bodies, and the tip portions are bent so as to extend in the stacking direction of the electrode bodies and not to contact the battery case. Preferred (third configuration).

Thereby, it can prevent that a positive electrode connection part and a negative electrode connection part are located on the end surface of an electrode body. Therefore, the positive electrode connecting portion and the negative electrode connecting portion can prevent variation in the gap between the positive electrode and the negative electrode constituting the electrode body. Therefore, it is possible to more reliably suppress variation in the infiltration property of the electrolytic solution with respect to the electrode body, and it is possible to more reliably prevent variation in battery performance.

In any one of the first to third configurations, one of the positive electrode and the negative electrode is disposed at one end of the electrode body in the stacking direction, and the one end Is in contact with one of the outer can and the sealing can, and the other end of the electrode body in the stacking direction is electrically connected to the other of the positive electrode and the negative electrode. It is preferable that the electric plate is disposed and the end on the other side is in contact with the other of the outer can and the sealing can (fourth configuration).

This eliminates the need to connect the positive electrode connecting portion and the negative electrode connecting portion to the outer can and the sealing can, respectively. Accordingly, it is not necessary to connect the positive electrode connecting portion to the outer can by welding as in the conventional case, so that a welding space is not required and the entire battery can be reduced in size. Also,
Since there is no need to dispose the negative electrode connection portion on the end face of the electrode body as in the conventional case, the negative electrode connection portion can prevent the gap between the positive electrode and the negative electrode from occurring.

Furthermore, the both ends of an electrode body can be surface-contacted with an exterior can and a sealing can by the above-mentioned structure. Thereby, an electrode body, an exterior can, and a sealing can can be electrically connected more reliably.

In the fourth configuration, an insulating plate is provided on the other side in the stacking direction of the electrode body inward of the stacking direction from the current collector plate, and the insulating plate is stacked in the stacking direction of the electrode body. See from
The positive electrode and the negative electrode have a protruding portion that protrudes outward, and the connecting portion having a polarity different from that of the current collector plate out of the positive electrode connecting portion and the negative electrode connecting portion is the protruding portion of the insulating plate. It is preferable to be bent so as to contact the part (fifth configuration).

By doing so, the front end portion of the positive electrode connection portion and the negative electrode connection portion, which has a polarity different from that of the current collector plate, is the current collector plate, and an outer can or a sealed can that is electrically connected to the current collector plate Can be prevented from touching. Therefore, it is possible to more reliably prevent a short circuit from occurring inside the battery by the positive electrode connection portion or the tip portion of the negative electrode connection portion.

In the first configuration, the other connection portion of the positive electrode connection portion and the negative electrode connection portion is:
Of the outer can and the sealing can, the other connecting portion is bent so as to extend toward a member having a different polarity, and the other connecting portion is positioned more than the center of the electrode body in the stacking direction. It is preferable that the outer can and the sealed can are connected to each other so as to be bundled at a position on the same member side as that of the one connecting portion (sixth configuration).

Thereby, it can prevent more reliably that the front-end | tip part of one connection part contacts the member from which this one connection part differs in polarity. Therefore, the occurrence of a short circuit inside the battery can be prevented more reliably.

According to the flat battery of one embodiment of the present invention, at least one of the positive electrode connecting portion and the negative electrode connecting portion is bent so that the tip portion extends in the stacking direction of the electrode body and does not contact the outer can and the sealed can. . Thereby, it is possible to prevent variation in the gap between the positive electrode and the negative electrode of the electrode body due to at least one of the positive electrode connection portion and the negative electrode connection portion. Therefore, it is possible to prevent variation in the infiltration property of the electrolyte with respect to the electrode body, and it is possible to prevent variation in battery performance.

FIG. 1 is a cross-sectional view showing a schematic configuration of a flat battery according to an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view showing an enlarged structure of the electrode body in the flat battery. FIG. 3 is a plan view showing the configuration of the positive electrode. FIG. 4 is a plan view showing the configuration of the negative electrode. FIG. 5 is a view when the electrode body is viewed from the negative electrode can side. FIG. 6 is a view when the electrode body is viewed from the positive electrode can side. FIG. 7 is a cross-sectional view showing how the electrode body is inserted into the negative electrode can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

(overall structure)
FIG. 1 is a cross-sectional view showing a schematic configuration of a flat battery 1 according to an embodiment of the present invention. The flat battery 1 includes a positive electrode can 10 as a bottomed cylindrical outer can, a negative electrode can 20 as a sealing can that covers an opening of the positive electrode can 10, an outer peripheral side of the positive electrode can 10, and an outer periphery of the negative electrode can 20. A gasket 30 disposed between the positive electrode can 10 and the negative electrode can 20, and an electrode body 40 accommodated in a space formed between the positive electrode can 10 and the negative electrode can 20. Therefore, the flat battery 1 is formed into a flat coin shape by combining the positive electrode can 10 and the negative electrode can 20 together. That is, the positive electrode can 10 and the negative electrode can 20 constitute a battery case having a space inside. In addition to the electrode body 40, a nonaqueous electrolytic solution (not shown; hereinafter simply referred to as an electrolytic solution) is also enclosed in the space of the battery case.

The positive electrode can 10 is made of a metal material such as stainless steel, and is formed into a bottomed cylindrical shape by press molding. The positive electrode can 10 includes a circular bottom portion 11 and a cylindrical peripheral wall portion 12 formed continuously with the bottom portion 11 on the outer periphery thereof. The peripheral wall portion 12 is provided so as to extend substantially vertically from the outer peripheral end of the bottom portion 11 in a longitudinal sectional view (the state illustrated in FIG. 1). As described later, the positive electrode can 10 has a peripheral wall portion 1 in a state where a gasket 30 is sandwiched between the positive electrode can 10 and the negative electrode can 20.
The opening end side of 2 is bent inward and caulked against the negative electrode can 20.

Similarly to the positive electrode can 10, the negative electrode can 20 is made of a metal material such as stainless steel and is formed in a bottomed cylindrical shape by press molding. The negative electrode can 20 has a cylindrical peripheral wall portion 22 whose outer shape is smaller than that of the peripheral wall portion 12 of the positive electrode can 10 and a circular flat portion 21 that closes one of the openings. Similarly to the peripheral wall portion 12 of the positive electrode can 10, the peripheral wall portion 22 is also provided so as to extend substantially perpendicular to the flat portion 21 in a longitudinal sectional view.

The peripheral wall portion 22 of the negative electrode can 20 is formed with a diameter-enlarged portion 22b whose diameter is increased stepwise compared to the base end portion 22a on the flat surface portion 21 side. That is, the peripheral wall portion 22 is formed with a step portion 22c between the base end portion 22a and the enlarged diameter portion 22b. As shown in FIG. 1, the open end side of the peripheral wall portion 12 of the positive electrode can 10 is bent and caulked with respect to the step portion 22c. That is,
In the positive electrode can 10, the opening end side of the peripheral wall portion 12 is fitted into the step portion 22 c of the negative electrode can 20.

The gasket 30 is made of polypropylene (PP). The gasket 30 is composed of a negative electrode can 20
The peripheral wall portions 12, 2 are sandwiched between the peripheral wall portion 22 of the positive electrode can 10 and the peripheral wall portion 12 of the positive electrode can 10.
Between the two. The material of the gasket 30 is not limited to PP, and a resin composition containing an olefin elastomer in polyphenylene sulfide (PPS), polytetrafluoroethylene (PFA), a polyamide resin, or the like may be used.

As shown in FIG. 2, the electrode body 40 includes a substantially disc-shaped positive electrode 41 accommodated in a bag-shaped separator 44 and a substantially disc-shaped negative electrode 51. A plurality of positive electrodes 41 and negative electrodes 51 are stacked so as to be alternately arranged in the thickness direction. Thereby, the electrode body 40 has a substantially cylindrical shape as a whole.

As shown in FIG. 1, the positive electrode 41 and the negative electrode 51 of the electrode body 40 are at both ends of the electrode body 40,
The negative electrode 51 is laminated so as to be positioned closer to the end side than the positive electrode 41. As shown in FIGS. 1 and 2, a positive electrode foil 4, which will be described later, is electrically connected to a positive electrode 41 at one end of the electrode body 40.
6 is arranged. An insulating sheet 47 is disposed between the positive foil 46 and the negative electrode 51.

As shown in FIG. 2, the positive electrode 41 is obtained by disposing positive electrode active material layers 42 containing a positive electrode active material such as lithium cobaltate on both surfaces of a positive electrode current collector 43 made of a metal foil such as aluminum. .

A plan view of the positive electrode 41 is shown in FIG. As shown in FIG. 3, the positive electrode current collector 43 includes a current collector main body 43 a having a shape in which a part of a disk is cut out, and a positive electrode lead 43 b (externally extending from the current collector main body 43 a ( Positive electrode connection portion). The current collector main body 43a is formed with notches 43c and 43d so that the portions facing each other in plan view are parallel to each other. A positive electrode lead 43b extends outwardly from one notch 43c of the current collector body 43a. A positive electrode active material layer 42 is provided on the surface of the current collector main body 43a. That is,
A current collector body 43 a of the positive electrode current collector 43 is covered with a positive electrode active material increase 42. The current collector main body 43a and the positive electrode active material layer 42 constitute a positive electrode main body 41a.

By providing the other notch 43d in the current collector body 43a of the positive electrode current collector 43,
A negative electrode lead 53b of the negative electrode 51, which will be described later, can be disposed more compactly with respect to the electrode body 40. That is, as shown in FIGS. 1 and 2, since the negative electrode lead 53b is arranged on the side of the electrode body 40 so as to extend in the stacking direction of the electrode body 40, the above-described notch 4
By providing 3d, the negative electrode lead 53b can be disposed closer to the electrode body 40.

As shown in FIG. 2, the negative electrode 51 includes a negative electrode active material layer 52 containing a negative electrode active material such as graphite.
The negative electrode current collector 53 made of a metal foil such as copper is disposed on both surfaces. Among the negative electrodes 51, the negative electrode located on the end side in the axial direction of the substantially cylindrical electrode body 40 is such that the negative electrode current collector 53 is located on the end side in the axial direction of the electrode body 40. The negative electrode active material layer 52 is provided only on one surface side of the body 53. The negative electrode current collector 53 of the negative electrode located on one end side among the negative electrodes located on both end sides in the axial direction of the electrode body 40 is in a state where the electrode body 40 is disposed in the space of the battery case. It contacts the flat portion 21 of the negative electrode can 20. The negative electrode current collector 53 of the negative electrode located on the other end side of the electrode body 40 is positioned on the bottom portion 11 of the positive electrode can 10 via the insulating sheet 47 and the positive electrode foil 48.

A plan view of the negative electrode 51 is shown in FIG. As shown in FIG. 4, the negative electrode current collector 53 includes a current collector main body 53a having a shape in which a part of a disk is cut out, and a negative electrode lead 53b extending outward from the current collector main body 53a ( Negative electrode connecting portion). The current collector main body 53a is formed with notches 53c and 53d so that the portions facing each other in plan view are parallel to each other. A negative electrode lead 53b extends outwardly from one notch 53c of the current collector body 53a. A negative electrode active material layer 52 is provided on the surface of the current collector main body 53a. That is,
A current collector main body 53 a of the negative electrode current collector 53 is covered with a negative electrode active material layer 52. The current collector main body 53a and the negative electrode active material layer 52 constitute a negative electrode main body 51a.

By providing the other notch 53d in the current collector body 53a of the negative electrode current collector 53,
The positive electrode lead 43 b of the positive electrode 41 can be arranged more compactly with respect to the electrode body 40. That is, as shown in FIGS. 1 and 2, since the positive electrode lead 43b is disposed on the side of the electrode body 40 so as to extend in the stacking direction of the electrode body 40, the above-described notch 53d is provided. Thus, the positive electrode lead 43 b can be disposed closer to the electrode body 40.

The separator 44 is a bag-like member formed in a circular shape in plan view, and houses the positive electrode main body 41a of the positive electrode 41 and the base end portion of the positive electrode lead 43b on the positive electrode main body 41a side as shown in FIG. It is formed in a possible size. The separator 44 is constituted by a microporous thin film made of polyethylene having excellent insulating properties. Thus, by forming the separator 44 with a microporous thin film, lithium ions can pass through the separator 44. The separator 44 is formed by wrapping the positive electrode 41 with a single sheet of a rectangular microporous thin film and bonding the overlapping portions of the sheet material by thermal welding or the like.

As shown in FIGS. 1, 2, 5, and 6, the positive electrode 41 and the negative electrode 51 have a positive electrode lead 43 b of each positive electrode 41 and a negative electrode lead 53 of each negative electrode 51 with respect to the positive electrode body 41 a and the negative electrode body 51 a.
It is laminated so that b extends in a different direction. That is, the positive electrode 41 and the negative electrode 51 are laminated so that the positive electrode lead 43b and the negative electrode lead 53b extend to the opposite sides with the positive electrode body 41a and the negative electrode body 51a interposed therebetween. Thereby, the positive electrode lead 43b of each positive electrode 41 and each negative electrode 5
One negative electrode lead 53b is overlaid in the thickness direction. The positive electrode lead 43b and the negative electrode lead 53b are connected to each other by welding while being stacked in the thickness direction.
The configuration of the positive electrode lead 43b and the negative electrode lead 53b will be described later.

As shown in FIGS. 1 and 2, the positive electrode foil 46 is further laminated on the one side of the electrode body 40 with respect to the positive electrode 41 and the negative electrode 51 laminated as described above. The positive foil 46 is
For example, it is made of a metal such as an aluminum alloy.

As shown in FIG. 6, the positive foil 46 has a substantially disc-shaped contact portion 46a and a lead portion 46b extending outward from the contact portion 46a. As with the positive electrode 41 and the negative electrode 51, the positive electrode foil 46 is integrally formed with a contact portion 46a and a lead portion 46b. Contact portion 46 of positive foil 46
a has the same diameter as the current collector body 53 a of the negative electrode current collector 53 of the negative electrode 51. Positive foil 46
The contact portion 46a is provided with one notch portion 46c, and the lead portion 46b extends outward from the notch portion 46c.

By laminating the positive electrode foil 46 having the above-described configuration with respect to the positive electrode 41 and the negative electrode 51, as shown in FIG. 6, the substantially disk-shaped contact portion 46 a of the positive electrode foil 46 has the positive electrode 41 and the negative electrode 51.
More outward in the radial direction. That is, the contact portion 46 a of the positive foil 46 has a protruding portion 46 d that protrudes outward from the positive electrode 41 and the negative electrode 51 when viewed from the stacking direction of the electrode body 40.

As shown in FIGS. 1 and 2, an insulating sheet 47 (insulating plate) is disposed on the inner side in the stacking direction of the electrode body 40 in the contact portion 46 a of the positive foil 46. The insulating sheet 47 has the same size and shape as the contact portion 46 a of the positive foil 46. Therefore, the insulating sheet 47 is also the positive electrode 4.
1 and the negative electrode 51 protrude outward in the radial direction. That is, the insulating sheet 47 also has the positive foil 46.
Similarly to the contact portion 46 a, the protrusion portion 47 a protrudes outward from the positive electrode 41 and the negative electrode 51 when viewed from the stacking direction of the electrode body 40. The protrusion 47a is located on the protrusion 46d of the contact portion 46a of the positive foil 46, and has the same shape and size as the protrusion 46d.

The insulating sheet 47 electrically insulates the negative electrode 51 and the positive foil 46 positioned on the end side in the axial direction of the electrode body 40. Further, the protrusion 47a of the insulating sheet 47 is brought into contact with the tip portion of the negative electrode lead 53b as will be described later. Therefore, the negative electrode lead 53b is formed by the insulating sheet 47.
It can prevent that the front-end | tip part, positive electrode foil 46, and the positive electrode can 10 produce a short circuit. In this embodiment, the tip portion of the negative electrode lead 53b is in contact with the protruding portion 47a of the insulating sheet 47. However, the present invention is not limited to this, and the negative electrode lead 53b is separated from the protruding portion 47a of the insulating sheet 47. It may be a length.

(Positive lead and negative lead)
Next, the configuration of the positive electrode lead 43b of the positive electrode 41 and the negative electrode lead 53b of the negative electrode 51 will be described.

As described above, the positive electrode 41 and the negative electrode 51 are connected to each other between the positive electrode leads 43b and the negative electrode lead 53b.
They are stacked so that they overlap each other (see FIGS. 1, 2, 5, and 6). That is, the positive electrode lead 43b and the negative electrode lead 53b are each laminated in the thickness direction.
The positive electrode lead 43b and the negative electrode lead 53b stacked in the thickness direction are joined to each other by ultrasonic welding in a bundled state at the central portion of the cylindrical electrode body 40 in the stacking direction. The positive electrode lead 43b and the negative electrode lead 53b that are joined to each other are bent toward the bottom 11 side of the positive electrode can 10, as shown in FIGS. Here, the central portion of the electrode body 40 in the stacking direction is the electrode body 40 across the center of the electrode body 40 in the stacking direction.
Means a range of about 1/5 of the height in the stacking direction. More preferably, the central portion of the electrode body 40 in the stacking direction means a range of about 10% of the height of the electrode body 40 from the center in the stacking direction to the top and bottom in the stacking direction.

Thus, by bending the positive electrode lead 43 b and the negative electrode lead 53 b toward the bottom 11 side of the positive electrode can 10, the positive electrode lead 43 b and the negative electrode lead 53 b protrude outward in the radial direction of the electrode body 40. Can be prevented. Therefore, the positive electrode lead 43 b and the negative electrode lead 53 b can be efficiently arranged in the space of the battery case formed by the negative electrode can 20 and the positive electrode can 10.

Moreover, by bending the positive electrode lead 43b and the negative electrode lead 53b toward the bottom 11 of the positive electrode can 10, the electrode body 40 can be easily placed inward of the negative electrode can 20 when assembling the flat battery 1 as will be described later. Can be arranged. Therefore, the assembly workability of the flat battery 1 can be improved by the above-described configuration.

Each of the positive electrode lead 43 b and the negative electrode lead 53 b has a tip portion at the bottom 1 of the positive electrode can 10.
It has such a length that it does not touch 1. Thus, the positive electrode lead 43b and the negative electrode lead 53
It is possible to prevent b from being positioned on the end surface of the end portion in the axial direction of the electrode body 40. Therefore, the positive electrode lead 43b and the negative electrode lead 53b prevent the positive electrode 41 and the negative electrode 51 of the electrode body 40 from being partially pressed in the axial direction of the electrode body 40, thereby preventing variation in the gap between the positive electrode 41 and the negative electrode 51. it can. Therefore, it is possible to prevent variation in the infiltration property of the electrolytic solution with respect to the electrode body 40 and to prevent occurrence of variation in battery performance of the flat battery 1.

Moreover, the tip of the negative electrode lead 53 b is in contact with the surface of the protruding portion 47 a of the insulating sheet 47 disposed on the positive foil 46. Thereby, it is possible to more reliably prevent a short circuit from occurring between the tip portion of the negative electrode lead 53 b and the positive foil 46 and the positive electrode can 10.

Further, as described above, the positive electrode lead 43b and the negative electrode lead 53b are respectively connected to the electrode body 4.
The positive lead 43b and the negative lead 5 are joined by bundling and bonding at the central portion in the stacking direction of 0.
When the 3b is bent, the positive electrode lead 43b and the negative electrode lead 53b can be prevented from greatly protruding outward in the radial direction of the electrode body 40. That is, the positive electrode lead 43b and the negative electrode lead 53b
Are bundled and joined at the central portion of the electrode body 40 in the stacking direction, so that when the positive electrode lead 43b and the negative electrode lead 53b are bent, the positive electrode leads 43b and the negative electrode lead 5 are joined together.
The range where 3b overlaps can be made into the half area | region of the lamination direction of the electrode body 40. FIG. Thereby, it is possible to prevent the bent positive electrode lead 43 b and negative electrode lead 53 b from greatly protruding outward in the radial direction of the electrode body 40.

In addition, the negative electrode lead 53b is at a position closer to the negative electrode can 20 than the center of the electrode body 40 in the stacking direction,
More preferably, they are welded together in a bundled state. Thereby, when the negative electrode lead 53 b is bent toward the positive electrode can 10, it is possible to more reliably prevent the tip portion of the negative electrode lead 53 b from contacting the bottom 11 of the positive electrode can 10. In addition, when the negative electrode lead 53b is made of copper as in the present embodiment, the welding area between the negative electrode leads 53b is increased by shifting the position where the negative electrode leads 53b are bundled from the center in the stacking direction of the electrode body 40 as described above. It can be ensured and the welding strength can be improved.

Further, the positive electrode lead 43b is positioned at the positive electrode can 10 side of the center of the electrode body 40 in the stacking direction,
They may be welded together in a bundled state.

(Manufacturing method of flat battery)
Next, a method for manufacturing the flat battery 1 having the above-described configuration will be described with reference to FIG.

First, the negative electrode can 20 and the positive electrode can 10 are each formed by press molding. Then, a gasket 30 is molded on the peripheral wall portion 22 of the negative electrode can 20.

On the other hand, a plurality of plate-like positive electrodes 41 covered by the separator 44 and a plurality of plate-like negative electrodes 5
1 are alternately stacked in the thickness direction so that the negative electrodes 51 are located at both ends in the stacking direction. At this time, the positive electrode 41 and the negative electrode 51 are laminated so that the positive electrode lead 43b and the negative electrode lead 53b overlap each other. And the positive electrode foil 46 and the insulating sheet 47 are laminated | stacked on the edge part of the lamination direction of the laminated body formed by laminating | stacking the positive electrode 41 and the negative electrode 51. FIG. The positive foil 46 is laminated on the laminate so that the lead portion 46b overlaps the positive lead 43b in the thickness direction.
Thereby, the substantially cylindrical electrode body 40 as shown in FIG. 7 is comprised.

Thus, in the state where the plurality of positive electrodes 41 and the plurality of negative electrodes 51 are stacked, the positive electrode leads 43b including the lead portions 46b of the positive electrode foil 46 and the negative electrode leads 53b are respectively stacked in the stacking direction of the electrode bodies 40. In the central part, they are joined by ultrasonic welding or the like in a state where they are overlapped with each other.

Then, the positive electrode lead 43b and the negative electrode lead 53b joined to each other are cut into predetermined lengths. The predetermined length means that when the positive electrode lead 43 b and the negative electrode lead 53 b are arranged in the positive electrode can 10 in a state where the positive electrode lead 10 b is bent toward the bottom 11 of the positive electrode can 10, the tip portion contacts the bottom 11 of the positive electrode can 10. The length is not.

The positive electrode lead 43b and the negative electrode lead 53b cut to a predetermined length are bent to the side where the positive electrode foil 46 and the insulating sheet 47 are laminated in the electrode body 40 (lower side in FIG. 7), respectively.

The electrode body 40 in which the positive electrode lead 43b and the negative electrode lead 53b are bent is inserted into the negative electrode can 20 from the side opposite to the positive electrode foil 46 and the insulating sheet 47, as shown in FIG. See arrow). At this time, since the positive electrode lead 43b and the negative electrode lead 53b are bent to the side where the positive electrode foil 46 and the insulating sheet 47 are laminated in the electrode body 40 as described above, the tips of the positive electrode lead 43b and the negative electrode lead 53b are bent. The portion is not caught on the inner surfaces of the negative electrode can 20 and the gasket 30. Therefore, the electrode body 40 can be smoothly inserted into the negative electrode can 20, and the assembly workability of the flat battery 1 can be improved.

After inserting the electrode body 40 into the negative electrode can 20 as shown in FIG. 7, the positive electrode can 10 is combined with the negative electrode can 20 so as to cover the opening of the negative electrode can 20. Thereafter, the open end of the peripheral wall portion 12 of the positive electrode can 10 is caulked to the step portion 22 c of the peripheral wall portion 22 of the negative electrode can 20 to connect the positive electrode can 10 and the negative electrode can 20.

  Thereby, the flat battery 1 having a configuration as shown in FIG. 1 is obtained.

(Other embodiments)
While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

In the embodiment, both the positive electrode lead 43 b and the negative electrode lead 53 b are bent toward the bottom 11 of the positive electrode can 10. However, at least one of the positive electrode lead 43 b and the negative electrode lead 53 b may be bent toward the bottom 11 of the positive electrode can 10. Further, the positive electrode lead 43b and the negative electrode lead 53b may be bent in different directions. Furthermore, both the positive electrode lead 43 b and the negative electrode lead 53 b may be bent toward the flat surface portion 21 side of the negative electrode can 20.

In the embodiment, the positive electrode can 10 is an outer can and the negative electrode can 20 is a sealed can. Conversely, the positive electrode can may be a sealed can and the negative electrode can may be an outer can.

In the above embodiment, the negative electrode can 20 and the positive electrode can 10 are each formed in a bottomed cylindrical shape, and the flat battery 1 is formed in a coin shape.
You may form in shapes other than column shape.

The flat battery according to the present invention can be used for a flat battery in which an electrode body having a positive electrode and a negative electrode laminated together is housed in a battery case.

1: flat battery, 10: positive electrode can (exterior can), 20: negative electrode can (sealing can), 40: electrode body, 4
1: positive electrode, 41a: positive electrode main body, 43b: positive electrode lead (positive electrode connecting portion), 46: positive electrode foil (current collector plate), 47: insulating sheet (insulating plate), 47a: protruding portion, 51: negative electrode, 51a: negative electrode Body,
53b: Negative electrode lead (negative electrode connection part)

Claims (4)

A bottomed circular cylindrical shape of the outer can,
A bottomed circular cylindrical sealing can be placed in the reverse dish-shaped with respect to outer Sokan so as to form a space between the outer can,
An electrode body housed in the space formed by combining the outer can and the sealing can,
The electrode body has a plurality of substantially disc-shaped positive and negative electrodes stacked alternately,
The positive electrode includes a positive electrode main body having a cutout portion formed so that opposing portions in a plan view are parallel to each other, and a positive electrode connection portion extending outward from one of the cutout portions of the positive electrode main body. The positive electrode connection portion is electrically connected to one of the outer can and the sealing can,
The negative electrode has a negative electrode body in which notches are formed so that portions facing each other in plan view are parallel to each other, and a negative electrode connection portion extending outward from one of the notches in the negative electrode body The negative electrode connection portion is electrically connected to the other of the outer can and the sealing can,
The positive electrode main body and the negative electrode main body are alternately stacked so that the positive electrode connection portions and the negative electrode connection portions protrude in different directions, and the positive electrode connection portions are stacked and the negative electrode connection portions are stacked. Have been
The positive electrode connecting portion and the negative electrode connecting portion are connected to each other so as to be bundled, and the tip portion extends in the stacking direction of the electrode body and is bent so as not to contact the outer can and the sealing can. And
The positive electrode connecting portion and the negative electrode connecting portion were each folded so that they extended toward the opening side of the sealing can in a state where the electrode body was disposed in the sealing can, and were bundled thereby. The positive electrode connecting portion is disposed on the side of the electrode body on the side where the other notch portion of the negative electrode main body is provided, and the bundled negative electrode connecting portion is connected to the other side of the positive electrode main body. A flat battery disposed on a side of the electrode body on a side where the cutout portion is provided . The flat battery according to claim 1,
The end portion of one side of the stacking direction of the electrode body, wherein with one of the positive electrode and the negative electrode are arranged, the ends of the one side in contact with the hand of the outer can and the sealing can And
A current collector plate electrically connected to the other of the positive electrode and the negative electrode is disposed at the other end portion in the stacking direction of the electrode body, and the other end portion includes the outer can and A flat battery in contact with the other of the sealing cans. The flat battery according to claim 2 ,
On the other side of the electrode body in the stacking direction, an insulating plate is provided on the inner side in the stacking direction than the current collector plate,
The insulating plate has a protruding portion that protrudes outward from the positive electrode and the negative electrode when viewed from the stacking direction of the electrode body,
A flat battery in which a connecting portion having a polarity different from that of the current collector plate among the positive electrode connecting portion and the negative electrode connecting portion is bent so that a tip portion is in contact with the protruding portion of the insulating plate. The flat battery according to any one of claims 1 to 3 ,
The connecting portion of the hand of the positive electrode connecting portion and the negative electrode connecting portion, the the outer can and the hand of the connection portion of the sealing can optionally be bent so as to extend toward the member different polarity,
Connecting portion of the hand, rather than the position of the stacking direction center of the electrode body, so that the connection portion of the other side and the polarity of the outer can and the sealing can are bundled at the position of the same member, connected to each other A flat battery.

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