JP2002305029A - Lithium-ion polymer secondary battery - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To obtain a required cross-sectional area of a terminal according to a discharge capacity and to reduce resistance at a terminal junction while securing flexibility. One end portion of a plurality of positive electrode current collector foils (12)
b is divided into a plurality of sets in the stacking order, and one end of each of the plurality of positive electrode terminals 23 corresponding to the number of sets is inserted between one end 12b of the positive electrode current collector foil stacked for each set, and End 12
b, and the other end 1 of the plurality of negative electrode current collector foils 15
5a is divided into a plurality of sets in the stacking order, and one end of each of the plurality of negative electrode terminals 21 according to the number of sets is inserted between the other end 15a of the negative electrode current collector foil stacked for each set and the other end thereof. And the package 26 is connected to the plurality of positive electrode terminals 2.
3 and the other ends of the plurality of negative terminals 21 each having a terminal outlet 26d which can be individually exposed, and the other ends of the plurality of positive terminals 23 and the other ends of the plurality of negative terminals 21. Are laminated and can be bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithium ion polymer secondary battery in which a positive electrode active material and a negative electrode active material are laminated via a polymer electrolyte layer.

[0002]

2. Description of the Related Art Conventionally, with the spread of portable devices such as video cameras and notebook personal computers, demand for thin and somewhat flexible batteries has been increasing. As this thin battery, a lithium ion polymer secondary battery formed by laminating a positive electrode sheet and a negative electrode sheet is known. The positive electrode sheet is made by applying an active material to the surface of a positive electrode current collector foil, and the negative electrode sheet is made by applying an active material to the surface of a negative electrode current collector foil. A polymer electrolyte layer is interposed between the active material of the positive electrode sheet and the active material of the negative electrode sheet. In this battery, a positive electrode terminal and a negative electrode terminal for extracting a potential difference in each active material as a current are provided on the positive electrode current collector foil and the negative electrode current collector foil,
By sealing the stacked body thus stacked with a package, a lithium ion polymer secondary battery is produced. In this lithium ion polymer secondary battery, desired electricity can be obtained by using the positive electrode terminal and the negative electrode terminal drawn out of the package as terminals of the battery.

In recent years, there has been a tendency to increase the discharge capacity of lithium ion polymer secondary batteries. A plurality of positive electrode sheets and a plurality of negative electrode sheets are stacked to increase the discharge capacity, or the discharge capacity is increased. The area of the positive electrode sheet and the single negative electrode sheet is increased, and the expanded positive electrode sheet and the negative electrode sheet are folded into a desired size to increase the discharge capacity. On the other hand, by using or folding a plurality of positive electrode sheets and negative electrode sheets to expand the discharge capacity, the ends of the plurality of positive electrode current collector foils and negative electrode current collector foils drawn out in layers are connected to each other. It is necessary to connect the positive terminal and the negative terminal. As this connection means, the ends of a plurality of positive electrode current collector foils and negative electrode current collector foils drawn out in layers are separated and bundled, and the bundled ends are sandwiched by a conductor also serving as a terminal, and bundled. A secondary battery has been proposed in which an end is welded to a conductor to extract electricity through the conductor (Japanese Patent Application Laid-Open No. Hei 7-26302).
9).

[0004]

However, when all the ends of the bundled positive electrode current collector foil or negative electrode current collector foil are joined to the conductor by welding, the mechanical strength at the joint is reduced by welding. And the flexibility of the battery is lost. In particular, when a conductor made of a bar-shaped metal piece having a relatively large terminal cross-sectional area is used to secure a cross-sectional area of the terminal corresponding to the increased discharge capacity, the flexibility at the joint is completely or completely eliminated. Have disadvantages that are lost. Conversely, when sandwiched by a relatively flexible conductor and the conductor and the bundled end are partially welded,
Although it is possible to maintain the flexibility of the battery, it is difficult to obtain the required cross-sectional area of the terminal according to the increased discharge capacity, and the battery is bent to bend from the end other than the welded portion and from the outside. There is a problem that a gap is formed between the sandwiched conductors and the conductivity is lost at that portion, and as a result, the resistance value increases and sufficient power cannot be obtained. An object of the present invention is to provide a lithium-ion polymer secondary battery in which a required cross-sectional area of a terminal according to a discharge capacity can be relatively easily obtained. Another object of the present invention is to provide a lithium ion polymer secondary battery that can reduce resistance at a terminal junction while ensuring flexibility.

[0005]

The invention according to claim 1 is
As shown in FIGS. 1 and 2, a positive electrode active material 13 is applied to each surface of a plurality of positive electrode current collector foils 12, and a negative electrode active material 16 is applied to each surface of a plurality of negative electrode current collector foils 15. A plurality of positive electrode current collector foils 12 and a plurality of negative electrode current collector foils 15 are laminated between a positive electrode active material 13 and a negative electrode active material 16 via a polymer electrolyte layer 17, respectively. One end of a sheet-like positive electrode terminal 23 is connected to all one ends 12b of the plurality of positive electrode current collector foils 12 protruding from one end 15b, and from the other end 12a of the positive electrode current collector foil 12 All other ends 15 of the plurality of projecting negative electrode current collector foils 15
A laminate of the positive electrode current collector foil 12 and the negative electrode current collector foil 15 is connected to one end of the sheet-shaped negative electrode terminal 21 so that the other end of the positive electrode terminal 23 and the other end of the negative electrode terminal 21 are exposed. Reference numeral 20 denotes an improvement of the lithium ion polymer secondary battery sealed by the package 26.

The characteristic configuration is that one end 12b of a plurality of positive electrode current collector foils 12 is divided into a plurality of sets in the order of lamination,
One end of each of the plurality of positive electrode terminals 23 corresponding to the number of sets is inserted between one end 12b of the positive electrode current collector foil laminated for each set and connected to one end 12b of the positive electrode current collector foil. The other end 15a of the plurality of negative electrode current collector foils 15 is divided into a plurality of sets in the stacking order, and one end of each of the plurality of negative electrode terminals 21 according to the number of sets is stacked for each set. Is connected between the other end 15a of the negative electrode current collector foil and the other end of the plurality of positive electrode terminals 23 and the other end of the plurality of negative electrode terminals 21. And the other ends of the plurality of positive terminals 23 and the other ends of the plurality of negative terminals 21 are stacked and adhered to each other. Where it was.

In the invention according to the first aspect, the terminals 21 and
It is possible to increase the cross-sectional area only by increasing the number of 23, and it is possible to relatively easily obtain the cross-sectional area of the terminal corresponding to the increased discharge capacity. In addition, a secondary battery that is relatively easily curved can be obtained as compared with a case where a single terminal having a relatively large thickness is connected. In addition, one end of the positive electrode terminal 23 is inserted between one ends 12 b stacked for each set of the plurality of positive electrode current collector foils 12, and one end of the negative electrode terminal 21 is connected to the set of the plurality of negative electrode current collector foils 15. Even if the secondary battery 10 is repeatedly bent, the positive electrode terminal 23 and the positive electrode terminal 23 are inserted between the other end portions 15a that are stacked every time.
There is no gap between the positive electrode current collector foil 12 sandwiching the negative electrode terminal 21 and the negative electrode terminal 21 and the negative electrode current collector foil 15 sandwiching the negative electrode terminal 21. The resistance at the junction can be sufficiently reduced.

The invention according to claim 2 is the invention according to claim 1, wherein the plurality of positive terminals 23 and the plurality of negative terminals 2 are provided.
Reference numeral 1 denotes a lithium ion polymer secondary battery which is an expanded metal or a perforated metal sheet, respectively. According to the second aspect of the present invention, by securing the flexibility of the terminals 21 and 23 themselves, the sheet-shaped secondary battery 10 is provided.
In addition, the flexibility of the secondary battery can be ensured, and the adhesion to the package 26 can be improved to ensure the hermeticity of the secondary battery with the package 26.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein one end 12b of the positive electrode current collector foil 12 in which each one end of the plurality of positive electrode terminals 23 is laminated for each set. One end of the positive electrode terminal 23 is connected to one end of the plurality of positive electrode current collector foils 12 by a plurality of burrs 25 which are caulked at predetermined intervals t in a direction intersecting the insertion direction in a state inserted between the plurality of positive electrode current collector foils 12. A predetermined direction in a direction intersecting the insertion direction with one end of each of the plurality of negative electrode terminals 21 being inserted between the other ends 15a of the negative electrode current collector foil 15 stacked for each set. This is a lithium ion polymer secondary battery in which one end of the negative electrode terminal 21 is connected to the other end 15a of the plurality of negative electrode current collector foils 15 by a plurality of stakes 25 caulked at intervals t.

The invention according to claim 5 is the invention according to claim 1 or 2, wherein one end 12b of the positive electrode current collector foil 12 in which one end of each of the plurality of positive electrode terminals 23 is laminated for each set. One end of the positive electrode terminal 23 is connected to one end of the plurality of positive electrode current collector foils 12 by ultrasonic welding at a plurality of positions at predetermined intervals t in a direction intersecting the insertion direction in a state interposed therebetween. 12b, a predetermined interval in a direction intersecting the insertion direction with one end of each of the plurality of negative electrode terminals 21 inserted between the other end 15a of the negative electrode current collector foil 15 stacked for each set. This is a lithium ion polymer secondary battery in which one end of the negative electrode terminal 21 is connected to the other end 15a of the plurality of negative electrode current collector foils 15 by ultrasonic welding at a plurality of points apart from each other.

According to the third and fifth aspects of the present invention, one end 12b of the plurality of positive electrode current collector foils 12 and the other end 15a of the plurality of negative electrode current collector foils 15 are set for each set. The positive electrode terminal 23 and the negative electrode terminal 21 corresponding to the number of sets are stacked, and the connection is performed by ultrasonic welding with a plurality of staples 25 caulked at a predetermined interval t or at a plurality of locations. Therefore, the increase in mechanical strength can be suppressed as compared with the case where all the portions of the stacked end portions 12a and 15b are joined, and the flexibility of the sheet-shaped secondary battery 10 conventionally has Can be secured.

The invention according to a fourth aspect is the invention according to the third aspect, wherein the material of the positive electrode current collector foil 12 or the material of the negative electrode current collector foil 15 is 0.05 to 0. Reinforcing foils or reinforcing thin plates 22 and 24 having a thickness of 5 mm are arranged on the outer surface of each of the positive electrode current collector foil 12 and the negative electrode current collector foil 15, which are laminated for each set of one or both ends. ,
A plurality of fasteners 2 via reinforcing foils or reinforcing thin plates 22 and 24
Reference numeral 5 denotes a caulked lithium ion polymer secondary battery. The invention according to claim 6 is the invention according to claim 5, which is the same material as the material of the positive electrode current collector foil 12 or the material of the negative electrode current collector foil 15, and has a thickness of 0.05 to 0.5 mm. Reinforcing foils or reinforcing thin plates 22 and 24 each having a thickness are disposed on the outer surface of each of the positive electrode current collector foil 12 and the negative electrode current collector foil 15 or a set of both ends thereof,
This is a lithium ion polymer secondary battery which is ultrasonically welded via reinforcing foils or thin reinforcing plates 22 and 24.

In the invention according to claim 4 or 6, the reinforcing foil or the reinforcing thin plates 22 and 24 are arranged so that when the secondary battery 10 is curved, the positive current collector foil 12 and Damage such as a crack at a swaged portion of the negative electrode current collector foil 15 can be prevented, and the reliability of the secondary battery 10 can be improved. Here, the reinforcing thin plates 22, 24
If the thickness is less than 0.05 mm, the reinforcing thin plates 22 and 24 may be broken when the ferrule 25 is swaged or when ultrasonic welding is performed. There is a possibility that poor crimping and poor welding may occur. In addition, the more preferable thickness of the reinforcing thin plates 22 and 24 is 0.1 to 0.3 mm.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIGS. 1 and 5,
The lithium ion polymer secondary battery 10 includes the positive electrode sheet 1
A polymer electrolyte layer 17 is interposed between the positive electrode sheet 1 and the negative electrode sheet 14, and the positive electrode sheet 11 and the negative electrode sheet 14 are laminated. The positive electrode sheet 11 has a positive electrode active material 13 applied to the surface of a positive electrode current collector foil 12, and the negative electrode sheet 14 has a negative electrode active material 16 applied to a surface of a negative electrode current collector foil 15. The polymer electrolyte layer 17 is interposed between the positive electrode active material 13 applied to the positive electrode current collector foil 12 and the negative electrode active material 16 applied to the surface of the negative electrode current collector foil 15. This lithium ion polymer secondary battery 10 uses a strip-shaped negative electrode current collector foil 15 in order to increase the discharge capacity. The strip-shaped negative electrode current collector foil 15 has a polymer electrolyte layer 17 on the surface of a negative electrode active material 16. It is folded with it. The negative electrode current collector foil 15 in this embodiment is a Cu foil, and the negative electrode active material 16 is a graphite-based active material.

As shown in FIGS. 9A and 9B, a specific procedure for forming the negative electrode active material 16 on the surface of the negative electrode current collector foil 15 was prepared by dispersing and mixing the active material in a solution. The slurry is applied to the upper surface of the strip-shaped negative electrode current collector foil 15 by a doctor blade method and dried. On the other hand, the negative electrode active material 16 is formed on the upper surface of the negative electrode current collector foil 15 in the drawing, which is the surface except for the other side portion 15b, and the polymer electrolyte layer 17 is formed by applying an electrolyte slurry on the upper surface of the negative electrode active material 16 and drying. It is made by doing. The polymer electrolyte layer 17 is formed so as to have an area covering the negative electrode active material 16. Specifically, as shown in FIG. 9C, an electrolyte slurry is applied so as to cover the negative electrode active material 16, and then dried to form an area covering the negative electrode active material 16.

Returning to FIG. 5, the lithium ion polymer secondary battery 10 has a plurality of positive electrode sheets each having an area corresponding to the folded area between the polymer electrolyte layers 17 excluding the folds of the folded negative electrode sheet 14. 11 is pinched.
The polymer electrolyte layer 17 is also formed on the surface of the positive electrode active material 13 of the sandwiched positive electrode sheet 11. The positive electrode current collector foil 12 in this embodiment is an Al foil, and the positive electrode active material 1
For example, LiCoO ₂ is used for 3.

As shown in FIGS. 8A and 8B, a specific procedure for producing the positive electrode sheet 11 is as follows. A slurry in which an active material is dispersed and mixed in a solution is applied by a doctor blade method and dried, followed by drying. Strip-shaped Al to be used as cathode current collector foil
First, the positive electrode active material 13 is formed on the upper surface of the foil 18. The positive electrode active material 13 is formed except for one side of the Al foil 18,
The polymer electrolyte layer 17 is formed to have an area covering the positive electrode active material 13. Specifically, FIG.
As shown in (c), the electrolyte slurry contains the positive electrode active material 13.
Is applied so as to cover the positive electrode active material 13 and then dried to form an area covering the positive electrode active material 13. Then Figure 8
As shown in (d), the strip-shaped Al foil 18 having the positive electrode active material 13 and the polymer electrolyte layer 17 forms the negative electrode sheet 14 together with the positive electrode active material 13 and the polymer electrolyte layer 17.
Is cut so as to have an area corresponding to the folded area. As a result, the positive electrode active material 13 is formed on the surface of the positive electrode current collector foil 12, and a plurality of positive electrode sheets 11 having a predetermined area and having the polymer electrolyte layer 17 on the surface of the positive electrode active material 13 are formed.

Next, as shown in FIG. 7, a polymer electrolyte layer 17 is interposed between the positive electrode sheet 11 and the negative electrode sheet 1.
4 are stacked. This lamination is performed by thermocompression bonding. That is, a plurality of positive electrode sheets 11 are arranged on the negative electrode sheet 14 at a predetermined pitch corresponding to the interval between the folds, and a pair of rollers 19, 19, which are heated to a predetermined temperature and rotate in opposite directions, are heated in this state. The positive electrode sheet 11 and the negative electrode sheet 14 are thermocompression-bonded with the polymer electrolyte layer 17 interposed therebetween as shown by the solid line arrows in the figure. The arrangement of the plurality of positive electrode sheets 11 on the negative electrode sheet 14 is such that one end 12 b of the plurality of positive electrode current collector foils 12 protrudes from one end 15 b of the band-shaped negative electrode current collector foil 15, Each of the positive electrode sheets 11 corresponds to a fold of the negative electrode sheet 14 so that the other end 15a of the negative electrode current collector foil 15 projects from the other end 12a of the plurality of positive electrode current collector foils 12. It is arranged with a part opened.

As shown in FIG. 6, the folding of the negative electrode sheet 14 on which the positive electrode sheet 11 is laminated is performed by alternately folding the folds of the negative electrode sheet 14 on which the positive electrode sheet 11 is not arranged. . When folded like this,
As shown in FIG. 5, the negative electrode sheet 1 thus folded
A plurality of positive electrode sheets 11 each having an area corresponding to the folded area are sandwiched between the polymer electrolyte layers 17 except for the fourth fold. As shown in FIG. 1, one end 12 b of the plurality of positive electrode current collector foils 12 protrudes from one end 15 b of the band-shaped negative electrode current collector foil 15, and The other end 15a is a plurality of positive electrode current collector foils 1
2 protrudes from the other end 12a.

As shown in FIGS. 1 and 2, one end 12b of a plurality of positive electrode current collector foils 12 protruding from one end 15b of the negative electrode current collector foil 15 is divided into a plurality of sets in the stacking order. Stacked. Then, each one end of the plurality of positive electrode terminals 23 corresponding to the number of sets is inserted between one end 12b of the positive electrode current collector foils 12 stacked for each set. In this embodiment, one end portion 12b of the positive electrode current collector foil 12 is divided into two sets in the stacking order and stacked, and two sheet-shaped positive electrode terminals 23 are formed.
Are inserted between one end 12b of the positive electrode current collector foil 12 laminated for each set, and connected to one end 12b of the positive electrode current collector foil 12. Similarly, a plurality of negative electrode current collector foils 15 protruding from the other end 12a of the positive electrode current collector foil 12
The other end 15a of the negative electrode current collector foil 15 in which two ends of two sheet-like negative electrode terminals 21 corresponding to the number of the sets are stacked for each set is also divided into two sets. It is inserted between the other ends 15 a and connected to the other end 15 a of the negative electrode current collector foil 15. A flexible expanded metal or a perforated metal sheet is used for each of the positive electrode terminal 23 and the negative electrode terminal 21 in this embodiment.

In this embodiment, the connection between one end 12b of the positive electrode current collector foil 12 laminated for each set and one end of the positive electrode terminal 23 and the other of the negative electrode current collector foil 15 laminated for each pair Is connected to one end of the negative electrode terminal 21 by a plurality of crimps that are crimped at predetermined intervals t (FIG. 2) in a direction intersecting the insertion direction in the state where the positive electrode terminal 23 and the negative electrode terminal 21 are inserted. This is performed by the stop 25. The connection by the armature 25 will be specifically described with reference to a case where the negative electrode terminal 21 is connected. As shown in FIG. 4, the armature 25 is connected to a cylindrical portion 25a and one end of the cylindrical portion 25a. It has a fixing flange 25c formed as follows. On the other hand, the material of the negative electrode current collector foil 15 is the same as the material of the negative electrode current collector foil 15 on the laminated outer surface of the other end portion 15a laminated for each set of the negative electrode current collector foil 15 with one end of the negative electrode terminal 21 inserted therebetween. A reinforcing foil or a reinforcing thin plate 22 made of Cu and having a thickness of 0.05 to 0.5 mm is disposed. Then, as shown in FIG. 4A, the other end 15 a and the one end of the negative electrode terminal 21, which are laminated for each set of the reinforcing foil or the reinforcing thin plate 22 and the negative electrode current collector foil 15, are laminated. In this state, a plurality of through holes 27 are formed at predetermined intervals t (FIG. 2) in a direction intersecting the insertion direction of one end of the negative electrode terminal 21.

As shown in FIG. 4B, the cylindrical portion 25a of the ferrule 25 is inserted into the through hole 27 until the fixing flange 25b contacts the hole edge. Then, the other end of the cylindrical portion 25a penetrates the through hole 27 and protrudes from the reinforcing foil or the reinforcing thin plate 22. By pressing the end of the punch 28 into the other end of the protruding cylindrical portion 25a,
Its end is mechanically pushed open to form a claw 25c shown in FIG. 4 (c). In this embodiment, a notch 25d is formed in the other end of the cylindrical portion 25a so that the end is split into eight when the cylindrical portion 25a is expanded.
The eight claws 25c are configured to form a radial shape when completely expanded. The eight radial claws 25c contact the other hole edge of the through hole 27, and the fixing flange 25a
At the same time, the other end 15a laminated for each set of the negative electrode current collector foil 15 is sandwiched together with one end of the reinforcing foil or the reinforcing thin plate 22 and one end of the negative electrode terminal 21. Thereby, one end of the negative electrode terminal 21 is connected to the other end 15a laminated for each set of the plurality of negative electrode current collector foils 15, respectively.

As shown in FIGS. 1 and 2, the outer surface of one end portion 12b of each set of the positive electrode current collector foils 12 is made of the same material as that of the positive electrode current collector foil 12. A reinforcing foil or thin reinforcing plate 24 made of Al and having a thickness of 0.05 to 0.5 mm is disposed. Then, one end 12 b and one end of the positive electrode terminal 23, which are stacked for each set of the reinforcing foil or the reinforcing thin plate 24 and the positive electrode current collector foil 12, are inserted into one end of the positive electrode terminal 23 in a state where they are stacked. A plurality of through holes (not shown) are formed at predetermined intervals t (FIG. 2) in a direction intersecting the direction. In this through-hole, the above-mentioned fitting 25
Is inserted and caulked, and one end of the positive electrode terminal 23 is connected to one end 12 b of each of the plurality of sets of the positive electrode current collector foils 12.
Connected to each other. Note that the reinforcing foils or reinforcing thin plates 22 and 24 disposed on the outer surface of the laminate are formed so as to have an area larger than the area covered by the claws 25c of the diaper 25, and the positive electrode current collector foil 12 and An excessive load is not applied to each of the negative electrode current collector foils 15.

The laminate 20 shown in FIG. 2 in which the strip-shaped negative electrode sheet 14 is folded with the plurality of positive electrode sheets 14 interposed therebetween and the positive electrode terminal 23 and the negative electrode terminal 21 are connected, as shown in FIG.
The package 26 is sealed with a package 26 so that the other end of the positive terminal 23 and the other end of the negative terminal 21 are exposed.
The other ends of the two positive terminals 23 and the two negative terminals 21
The number of terminal outlets 26d is formed in accordance with the number of sets that can individually expose the other end of the terminal. As shown in FIGS. 1 and 5,
The package 26 according to the present embodiment includes the laminate 20.
A pair of package sheets 26a covering the front and back surfaces of
26b, and a pair of auxiliary sheets 26c which are disposed in a folded state between the two positive terminals 23, 23 and between the two negative terminals 21, 21 respectively. The pair of package sheets 26a and 26b and the pair of auxiliary sheets 26c are each made of an aluminum foil on which modified polypropylene is laminated. A pair of auxiliary sheets 2
6c is folded back so that the laminated modified polypropylene is exposed, and in this state, it is disposed between the two positive terminals 23 and 23 and between the two negative terminals 21 and 21. The stacked body 20 is sandwiched between the pair of package sheets 26a and 26b from the front and back surfaces, and the stacked periphery of the pair of package sheets 26 is thermocompression-bonded in a vacuum atmosphere to form the stacked body 20 with the other end of the positive electrode terminal 23 and the negative electrode. The other end of the terminal 21 is hermetically sealed by the package 26 so as to be exposed to the outside.

As shown in FIG. 1, at the time of sealing, the periphery of the pair of package sheets 26a and 26b and the auxiliary sheet 26c
The positive terminal 23 and the negative terminal 21 are respectively sandwiched between them, and in that state, a pair of package sheets 26a, 26b
And the auxiliary sheet 26c are thermocompression-bonded, and the positive electrode terminal 23
And package 26 in a portion sandwiching negative electrode terminal 21
A terminal outlet 26d after thermocompression bonding is formed. In this embodiment, since the positive electrode terminal 23 and the negative electrode terminal 21 are each formed of an expanded metal or a perforated metal sheet, when the periphery of the package sheet 26 and the auxiliary sheet 26c are thermocompression-bonded, they are laminated on aluminum foil. The modified polypropylene thus melted melts and penetrates into the stitches of the expanded metal or the perforations of the metal sheet, and then the modified polypropylene hardens, so that the terminal outlet 26d in the package 26 and the positive electrode terminal 2
3 and the negative electrode terminal 21 are ensured in close contact with each other, and the package 20 is reliably sealed by the package 26.

As shown in FIG. 3, the other ends of the plurality of positive terminals 23, 23 and the other ends of the plurality of negative terminals 21, 21 respectively drawn out from the respective terminal outlets 26d of the package 26 are laminated. And can be bonded. In this embodiment, the other ends of the expanded metal or perforated metal sheet as terminals are laminated and resistance-welded or ultrasonic-welded, or crimped or soldered. And the other ends of the positive and negative terminals 21 and 23 are bonded together, and the other ends of the positive and negative terminals 21 and 23 bonded as described above are used as terminals of a battery to obtain desired electricity. Is done.

In the lithium ion polymer secondary battery 10 configured as described above, one end portion 12b of the plurality of positive electrode current collector foils 12 is divided into a plurality of sets in the stacking order, and a plurality of positive electrode terminals corresponding to the number of sets are provided. One end of each of the plurality of negative electrode current collector foils 15 is inserted between one end 12b of the positive electrode current collector foils 12 laminated for each set and connected to one end 12b thereof. The end portion 15a is divided into a plurality of sets in the stacking order, and one end of each of the plurality of negative electrode terminals 21 corresponding to the number of sets is inserted between the other end portion 15a of the negative electrode current collector foil 15 laminated for each set. Connected to the other end 15a, it is possible to enlarge the cross-sectional area only by increasing the number of terminals 21 and 23, and it is relatively easy to increase the cross-sectional area of the terminal according to the increased discharge capacity. Compared to connecting a single terminal with a relatively large thickness. , It is possible to obtain a secondary battery likely to be relatively curved.

One end of the positive electrode terminal 23 is inserted between one end 12b of each set of the plurality of positive electrode current collector foils 12 which are divided into a plurality of sets and stacked. Is inserted between the other end portions 15a of each set, which is divided into a plurality of sets and stacked in a stacking order of the plurality of negative electrode current collector foils 15, so that the secondary battery 10 can be repeatedly bent. Between the positive electrode terminal 23 and the positive electrode current collector foil 12 sandwiching the positive electrode terminal 23, or between the negative electrode terminal 21 and the negative electrode terminal 21.
No gap is generated between the negative electrode current collector foils 15 sandwiching them, and the conductivity at the contact portion is ensured, and the resistance at the terminal junction can be sufficiently reduced.

One end 12b of the plurality of positive electrode current collector foils 12 and the other end 15b of the plurality of negative electrode current collector foils 15
a and the positive electrode terminal 23 and the negative electrode terminal 21 are connected by a plurality of staples 25 caulked at a predetermined interval t. To suppress the increase in mechanical strength,
The flexibility that the sheet-shaped secondary battery 10 has conventionally can be secured. Further, a reinforcing foil or a reinforcing thin plate 24 is disposed on the outer surface of the laminated one end 12b of the positive electrode current collector foil 12, and is disposed on the outer surface of the laminated other end 15a of the negative electrode current collector foil 15. Since the reinforcing foil or the reinforcing thin plate 22 is arranged, when the secondary battery 10 is curved, it is possible to prevent damage such as cracks at the caulked portions of the positive electrode current collector foil 12 and the negative electrode current collector foil 15 on the outside. Secondary battery 10
Can be improved in reliability.

In the above-described embodiment, the strip-shaped negative electrode sheet 14 in which a plurality of positive electrode sheets 11 are thermocompression-bonded at a predetermined pitch is alternately bent at a fold where the positive electrode sheet 11 is not arranged. A plurality of anode sheets having the same shape and size as the cathode sheet are prepared in the same number as the cathode sheet, a polymer electrolyte layer is interposed between the cathode active material and the anode active material, and a plurality of cathodes constituting the sheets are provided. It may be a laminate of a current collector foil and a plurality of negative electrode current collector foils.

In the embodiment described above, one end of each of the terminals 21 and 23 is connected to one end 12 b of the positive electrode current collector foil 12 or the other end of the negative electrode current collector 15a, one end 12 of the positive electrode current collector foil 12 in which one end of each of the plurality of positive electrode terminals 23 is stacked for each set.
b, one end of each of the positive electrode terminals 23 is connected to one end of each of the plurality of positive electrode current collector foils 12 by ultrasonic welding at a plurality of locations at predetermined intervals t in a direction intersecting the insertion direction. The other end 15a of the negative electrode current collector foil 15 connected to the portion 12b and one end of each of the plurality of negative electrode terminals 21 is laminated for each set.
Each end of the negative electrode terminal 21 is ultrasonically welded at a predetermined interval t in a direction intersecting the insertion direction in a state interposed between the negative electrode terminal 21 and the other end of the plurality of negative electrode current collector foils 15. 15a. In the case of connection by ultrasonic welding, it is possible to save the labor of forming the through hole 27 required for connection using the ferrule 25, and to join all parts of the stacked end portions 12a and 15b. In this case, the increase in mechanical strength can be suppressed, and the flexibility can be ensured.

[0032]

As described above, according to the present invention, one end of each of the plurality of positive electrode current collector foils is divided into a plurality of sets in the stacking order, and one end of each of the plurality of positive electrode terminals corresponding to the number of sets is separated. Inserted between one end of the positive electrode current collector foil laminated for each set, connected to one end of the positive electrode current collector foil, and laminated the other end of the plurality of negative electrode current collector foils The negative electrode current collector foil is divided into a plurality of sets in order, and one end of each of the plurality of negative electrode terminals corresponding to the number of sets is inserted between the other ends of the negative electrode current collector foils stacked for each set, and the other end of the negative electrode current collector foil is inserted. The package has a number of terminal outlets corresponding to the number of sets that can individually expose the other end of the plurality of positive terminals and the other end of the plurality of negative terminals, and the plurality of positive terminals And the other ends of the plurality of negative electrode terminals are laminated and adhered to each other, so that the cross-sectional area can be enlarged simply by increasing the number of terminals. And the cross-sectional area of the terminal corresponding to the increased discharge capacity can be obtained relatively easily, and it is relatively easy to bend as compared with the case of connecting a single terminal having a relatively large thickness. A secondary battery can be obtained.

Further, one end of the positive electrode terminal is inserted between one ends laminated for each of a plurality of sets of the positive electrode current collector foil, and one end of the negative electrode terminal is provided for each of the plurality of sets of the negative electrode current collector foil. Since it is inserted between the other end of the stack, even if the secondary battery is repeatedly bent, between the positive electrode terminal and the positive electrode current collector foil sandwiching the positive electrode terminal, or between the negative electrode terminal and the negative electrode terminal There is no gap between the sandwiched negative electrode current collector foils, the conductivity at the contact portion is ensured, and the resistance at the terminal junction can be sufficiently reduced. Furthermore, one end of the plurality of positive electrode current collector foils and the other end of the plurality of negative electrode current collector foils are laminated for each set, and the positive electrode terminal and the negative electrode terminal corresponding to the number of sets are connected. However, if the connection is made by a plurality of crimps which are caulked at a predetermined interval or by ultrasonic welding at a plurality of places, mechanical connection is made in comparison with the case where all parts of the laminated ends are joined. Therefore, the increase in the mechanical strength can be suppressed, and the flexibility that the sheet-shaped secondary battery 10 has conventionally can be secured.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line BB of FIG. 5 showing a secondary battery of the present invention.

FIG. 2 is a perspective view showing a laminate in which the positive and negative electrode sheets are laminated and terminals are connected.

FIG. 3 is a perspective view showing a secondary battery of the present invention in which the laminate is sealed by a package.

FIG. 4 is a sectional view showing a procedure for swaging the staple.

FIG. 5 is a cross-sectional view of the secondary battery taken along line AA of FIG. 1;

FIG. 6 is an exploded perspective view showing the configuration of the secondary battery.

FIG. 7 is a perspective view showing a state in which a positive electrode sheet is thermocompression-bonded to the negative electrode sheet.

FIG. 8 is a view showing a manufacturing process of the positive electrode sheet.

FIG. 9 is a view showing a manufacturing process of the negative electrode sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lithium ion polymer secondary battery 12 Positive electrode collector foil 12a The other end 12b One end 13 Positive electrode active material 15 Negative current collector foil 15a The other end 15b One end 16 Negative electrode active material 17 Polymer electrolyte Layer 21 Negative terminal 22 Reinforcement foil or thin sheet 23 Positive terminal 24 Reinforcement foil or thin sheet 25 Stopper 26 Package 26d Terminal outlet t Predetermined interval

Continued on the front page (72) Inventor Tadashi Kobayashi 1-297 Kitabukuro-cho, Omiya-shi, Saitama F-term in Mitsubishi Materials Corporation General Research Laboratory 5H017 AA03 AS01 CC01 HH03 5H022 AA09 BB11 CC02 5H029 AJ06 BJ04 BJ12 CJ05 DJ05 DJ07 DJ09 EJ01 HJ04

Claims (6)

[Claims] A positive electrode active material (13) is applied to each surface of a plurality of positive electrode current collector foils (12), and a negative electrode active material (16) is applied to each surface of a plurality of negative electrode current collector foils (15). Coated, the plurality of positive electrode current collector foils (12) and the plurality of negative electrode current collector foils (15) are each a polymer electrolyte between the positive electrode active material (13) and the negative electrode active material (16). Laminated through a layer (17), the negative electrode current collector foil (15)
A sheet-like positive electrode terminal is provided on all one ends (12b) of the plurality of positive electrode current collector foils (12) projecting from one end (15b) of the
One end of (23) is connected, and all other ends (15a) of the plurality of negative electrode current collector foils (15) projecting from the other end (12a) of the positive electrode current collector foil (12) One end of a sheet-shaped negative electrode terminal (21) is connected to the positive electrode current collector foil (12) so that the other end of the positive electrode terminal (23) and the other end of the negative electrode terminal (21) are exposed. In the lithium ion polymer secondary battery in which (20) with the negative electrode current collector foil (15) is sealed by a package (26), one end (12b) of the plurality of positive electrode current collector foils (12) Are divided into a plurality of sets in the stacking order, and one end of each of the plurality of positive electrode terminals (23) corresponding to the number of sets is inserted between one end (12b) of the positive electrode current collector foil stacked for each set. Is connected to one end (12b) of the positive electrode current collector foil, and the other end (15a) of the plurality of negative electrode current collector foils (15) is divided into a plurality of sets in a stacking order. One end of each of the plurality of negative electrode terminals (21) according to the number is The package (26) is inserted between the other end (15a) of the laminated negative electrode current collector foil and connected to the other end (15a) of the negative electrode current collector foil; The other end of the positive electrode terminal (23) and the other end of each of the plurality of negative electrode terminals (21) have a number of terminal outlets (26d) corresponding to the number of sets that can be individually exposed, and The other end of the positive electrode terminal (23) and the other end of each of the plurality of negative electrode terminals (21) are laminated and adhered to each other. 2. A plurality of positive terminals (23) and a plurality of negative terminals.
The lithium ion polymer secondary battery according to claim 1, wherein (21) is an expanded metal or a perforated metal sheet, respectively. 3. The insertion direction intersects with one end of each of the plurality of positive electrode terminals (23) inserted between one ends (12b) of the positive electrode current collector foils (12) stacked for each set. Predetermined direction in the direction
Each end of the positive electrode terminal (23) is connected to one end (12b) of the plurality of positive electrode current collector foils (12) by a plurality of staples (25) that have been caulked by opening (t), When one end of each of the plurality of negative electrode terminals (21) is inserted between the other end (15a) of the negative electrode current collector foil (15) laminated for each set, a predetermined direction is provided in a direction intersecting the insertion direction. Each end of the negative electrode terminal (21) is formed by a plurality of crimps (25) which are caulked at intervals (t), and the other end (15a) of the plurality of negative electrode current collector foils (15)
The lithium ion polymer secondary battery according to claim 1, wherein the lithium ion polymer secondary battery is connected to a battery. 4. The same material as the material of the positive electrode current collector foil (12) or the material of the negative electrode current collector foil (15), and is 0.05 to 0.5 mm.
A reinforcing foil or a reinforcing thin plate having a thickness of (22, 24) is laminated for each set of one or both ends of the positive electrode current collector foil (12) or the negative electrode current collector foil (15). 4. The lithium ion polymer secondary battery according to claim 3, wherein a plurality of claws (25) are arranged on the respective outer surfaces and are each caulked via the reinforcing foil or the reinforcing thin plate (22, 24). 5. 5. A direction intersecting the insertion direction with one end of each of the plurality of positive electrode terminals (23) being inserted between one end of the positive electrode current collector foil (12) laminated for each set. Predetermined interval (t)
And one end of the positive electrode terminal (23) is connected to one end (12b) of the plurality of positive electrode current collector foils (12) by ultrasonic welding at a plurality of locations, and a plurality of negative electrode terminals (21 ) Is inserted between the other end (15a) of the negative electrode current collector foil (15) laminated for each set at a predetermined interval (t) in a direction intersecting the insertion direction. Each end of the negative electrode terminal (21) is ultrasonically welded at a plurality of places to open the other end (15) of the plurality of negative electrode current collector foils (15).
3. The lithium ion polymer secondary battery according to claim 1, which is connected to a). 6. The same material as the material of the positive electrode current collector foil (12) or the material of the negative electrode current collector foil (15), and is 0.05 to 0.5 mm.
A reinforcing foil or a reinforcing thin plate having a thickness of (22, 24) is laminated for each set of one or both ends of the positive electrode current collector foil (12) or the negative electrode current collector foil (15). 6. The lithium ion polymer secondary battery according to claim 5, wherein the lithium ion polymer secondary battery is disposed on each outer surface and is ultrasonically welded through the reinforcing foil or the reinforcing thin plate (22, 24).