JP2000082487A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively perform welding of multiple sheets of metal foil via window parts by forming, in a part of one metal plate of each catching part in a current collecting part of a collector, the window part communicating with the gap between the other metal plate and itself. SOLUTION: A negative electrode collector 2 is mounted on the upper end of a power generation element 1, and the edge parts of each of plural sheets of a negative electrode 1a are pinched and held in the gap of each pinch holding part 2c of a current collecting part 2a. A part excluding a window part 2e of one copper plate of each of the pinch holding parts 2c is crimped with the other copper plate. The part excluding a window part 2e of the one copper plate of each of the catching parts 2c is welded to the other copper plate by means of ultrasonic waves, and the window part 2e of the one copper plate of each of the catching parts 2c is also subjected ultrasonic welding to the other copper plate. Similarly for a positive electrode collector, each part having exposed Al foil of the edge parts of a positive electrode 1b projecting toward the lower end of the power generation element 1 is crimped with and subjected to ultrasonic welding to a part which excludes a window part of the other Al plate, and the window part of the other Al plate is subjected to ultrasonic welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery provided with a winding type power generating element in which band-like positive and negative electrodes are wound via a band-like separator.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the configuration of a non-aqueous electrolyte secondary battery provided with a winding type power generating element 1 having a long cylindrical shape. This power generating element 1 is configured by winding a strip-shaped negative electrode 1a and a positive electrode 1b into a long cylindrical shape via a strip-shaped separator 1c.
By winding the negative electrode 1a and the positive electrode 1b slightly up and down, respectively, the negative electrode 1a
, And only the lower edge of the positive electrode 1b protrudes from the lower end. At this time, the active material is not applied to the upper edge of the negative electrode 1a, and the active material is not applied to the lower edge of the positive electrode 1b. To expose the metal foil. In addition, the separator 1c is wound so as to cover the portion where the negative electrode 1a and the positive electrode 1b overlap, but not to cover the upper and lower edges.

In the above-mentioned non-aqueous electrolyte secondary battery, a negative electrode current collector 2 and a positive electrode current collector 3 as shown in FIG. The negative electrode current collector 2
A current collecting portion 2a is formed above a central side of the upper end of the power generating element 1 and made of a copper plate, and a flat terminal connection portion 2b is pulled out from the current collecting portion 2a to form one of the upper ends of the power generating element 1. Are arranged above the semicircular portion of the above. Current collector 2
a is obtained by bending a copper plate of the negative electrode current collector 2,
The holding portions 2c are formed at three places, and the flat plate portions 2d are provided between the holding portions 2c. The holding portion 2c is a portion in which two copper plates are erected face to face by bending a horizontal flat copper plate upward and turning back at the top, and the two erected faces are opposed to each other. A gap that opens downward is provided between the copper plates. The flat plate portion 2d is a horizontal flat plate-shaped portion that connects adjacent ones of the holding portions 2c at their lower ends.
The lower end of the negative electrode terminal 4 is connected and fixed to the terminal connection portion 2b by caulking.

The positive electrode current collector 3 is formed by pressing an aluminum plate, has the same configuration as the negative electrode current collector 2, and has a current collector 3a which is turned upside down. One end of the current collecting portion 3a is drawn out along the side surface of the power generating element 1 to above the other semicircular portion of the upper end portion, and is connected to the horizontal flat terminal connecting portion 3b. The lower end of the positive electrode terminal 5 is connected and fixed to the terminal connection portion 3b by caulking.

[0005] As shown in FIG.
The edge of the negative electrode 1a protruding from the upper end of the power generating element 1 is clamped together by a plurality of sheets in the gaps between the holding portions 2c of the current collector 2a, and connected and fixed by ultrasonic welding.
At this time, the edge of the negative electrode 1a protruding from the upper end of the power generating element 1 is divided into a plurality of sheets by a jig or the like in advance, and this is applied to each of the holding sections 2c of the current collecting section 2a of the negative electrode current collector 2. Insert it. In the case where the flat plate portion 2d has a V-shaped cross section projecting downward, the negative electrode 1a can be obtained simply by pressing the current collector 2a against the upper end of the power generating element 1 without using such a jig. Can be sorted into a plurality of sheets and inserted into each holding portion 2c. However, when the current collector 2a is directly pressed against the upper end of the power generating element 1, the thin metal foil on the edge of the negative electrode 1a may be wrinkled or broken and cannot be smoothly distributed. May come into contact with the upper end of the positive electrode 1b in the power generating element 1 to cause a short circuit between the positive and negative electrodes. Therefore, it has been proposed to form a flat plate portion 2d like this between the sandwiching portions 2c.

Further, a positive electrode current collector 3 not shown in FIG.
Similarly to the negative electrode current collector 2, the edge of the positive electrode 1b protruding from the lower end of the power generating element 1 is sandwiched between the clamping portions 3c of the current collecting portion 3a, caulked, and connected and fixed by ultrasonic welding.

In the drawings, for simplicity, the negative electrode 1a, the positive electrode 1b, etc. of the power generating element 1 are coarsely wound with a small number of windings. In the gaps between the holding parts 2c, 3c of the electric parts 2a, 3a, many edge parts of the negative electrode 1a and the positive electrode 1b are respectively inserted and fixed. In addition, these negative electrode current collectors 2
The current collectors 2a and 3a of the positive electrode current collector 3 may be arranged not only on one side of the center of the power generating element 1 but also above and below both sides of the center to improve current collection efficiency.

[0008]

However, while the extremely thin metal foil is exposed at the edges of the negative electrode 1a and the positive electrode 1b of the power generating element 1, the negative electrode current collector 2 and the positive electrode current collector 2 are exposed. The metal plates of the holding portions 2c, 3c of the current collectors 2a, 3a in the body 3 have a certain thickness in order to pass a sufficient charge / discharge current and to hold the power generating element 1 in the battery case. . Accordingly, the thickness of the holding portions 2c, 3c is large.
When ultrasonic welding is performed through a plurality of metal plates, the ultrasonic vibration is not reliably transmitted to a large number of metal foils at the edge portions of the negative electrode 1a and the positive electrode 1b sandwiched therebetween, and particularly, in the middle of the overlapped metal foil. There has been a problem that the melt bonding of the nearby metal foil is not sufficient, and the battery characteristics may deteriorate as the number of charge / discharge cycles of the battery increases. Further, when the power of ultrasonic welding is increased to solve this problem, a new problem arises in that the edges of the negative electrode 1a and the positive electrode 1b made of thin metal foil may be broken by strong ultrasonic vibration. .

The present invention has been made in order to cope with such a situation. By providing a window on a part of one of the metal plates of the holding portion, a large number of metal foils can be welded through the window. It is an object of the present invention to provide a battery capable of reliably performing the following.

[0010]

According to a first aspect of the present invention, a plurality of metal plates are provided so as to face each other through a gap opened at the base side by folding a substantially vertical metal plate at the top. The current collector of the current collector, which is composed of a clamping portion and a flat plate portion that connects adjacent ones of the clamping portions with a flat metal plate on the base side, winds the band-like positive and negative electrodes in the winding axis direction, respectively. Positive and negative electrodes are disposed with the base side facing each of both ends of the winding shaft of a winding type power generating element that is wound through a band-shaped separator while being shifted to, and projecting from both ends of the winding shaft of this power generating element In the battery, the edge portions of which are sandwiched between the nearest holding portions of the current collector and connected and fixed by welding, a part of one metal plate of each of the holding portions in the current collector of the current collector and Make sure that a window that leads to the gap between the And butterflies.

According to the first aspect of the present invention, since the window is formed in a part of one of the metal plates of the holding portion, the edge portions of the plurality of electrodes sandwiched by the holding portion through the window are formed. The connection can be fixed by welding reliably by welding. Further, since the edge portion of the electrode is exposed to one side through the window portion, welding can be performed by directly applying heat by laser welding or the like, not limited to welding by vibration such as ultrasonic welding.

According to a second aspect of the present invention, the edge of the electrode is
It is inserted between the two metal plates of the holding portion of the current collector and caulked, and between the window portion of one metal plate and the other metal plate, and the portion other than the window portion of one metal plate and the other. And is connected and fixed to the metal plate by ultrasonic welding.

According to the second aspect of the present invention, the edges of the plurality of electrodes sandwiched between the holding portions are swaged and superposed between a portion other than the window of one metal plate and the other metal plate. It is held securely by sonic welding as before. Then, between the window of one metal plate and the other metal plate, the edges of the plurality of electrodes are directly ultrasonically welded, so that they are securely welded and securely connected and fixed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a perspective view showing a negative electrode current collector fixedly connected to a power generating element, and FIG. 2 is a current collector of the negative electrode current collector. It is a partial expansion perspective view which expands and shows a part. Components having the same functions as those of the conventional example shown in FIGS. 3 to 5 are denoted by the same reference numerals.

In this embodiment, a non-aqueous electrolyte secondary battery including a wound power generating element 1 wound in a long cylindrical shape will be described. As shown in FIG. 3, the power generating element 1 of this non-aqueous electrolyte secondary battery is configured such that the negative electrode 1a and the positive electrode 1b are slightly shifted in the vertical direction (winding axis direction), respectively, and wound. 1, only the upper edge of the negative electrode 1a protrudes from the upper end, and only the lower edge of the positive electrode 1b protrudes from the lower end. The negative electrode 1a is obtained by applying a negative electrode active material such as graphite to the surface of a strip-shaped copper foil, and the positive electrode 1b is obtained by applying a positive electrode active material such as a lithium-cobalt composite oxide to the surface of a strip-shaped aluminum foil. is there. However, by applying the negative electrode active material only to the portion excluding the upper edge, the negative electrode 1a is applied with the positive electrode active material only to the portion excluding the lower edge,
The copper foil and the aluminum foil are exposed and protruded from the upper and lower ends of the power generating element 1, respectively. Separator 1c
Used a strip-shaped microporous resin film.
It is wound so as to cover the overlapping portion of the positive electrode 1a and the positive electrode 1b, but not to cover the upper and lower edges.

A negative electrode current collector 2 as shown in FIG. 1 is connected to the negative electrode 1a of the power generating element 1. The negative electrode current collector 2
A current collecting portion 2a is formed above a central side of the upper end of the power generating element 1 and made of a copper plate, and a flat terminal connection portion 2b is pulled out from the current collecting portion 2a to form one of the upper ends of the power generating element 1. Are arranged above the semicircular portion of the above. Current collector 2
a is obtained by bending a copper plate of the negative electrode current collector 2,
The holding portions 2c are formed at three places, and the flat plate portions 2d are provided between the holding portions 2c. The holding portion 2c is a portion in which two copper plates are erected face to face by bending a horizontal flat copper plate upward and turning back at the top, and the two erected faces are opposed to each other. A gap that opens downward is provided between the copper plates. Further, a window 2e is formed in a part of one of these two copper plates. In the present embodiment, as shown in FIG. 2, two windows 2e are formed except for both ends and a central portion of one copper plate. Although the number and the opening position of the windows 2e are arbitrary, it is preferable that the window 2e be in a range of 10 to 80% of the entire area of one copper plate. Also, here, a case is shown in which the window portion 2e is open from one copper plate to the entire top of these copper plates so that the state of ultrasonic welding described later is easy to see, but this top is not necessarily opened. There is no.

The flat plate portion 2d is a horizontal flat plate-like portion that connects adjacent ones of the holding portions 2c at their lower ends, and is provided so that a certain interval is opened between the holding portions 2c. . Negative terminal 4
Is connected and fixed by caulking.

The power generating element 1 is formed by inserting a comb-shaped jig having downwardly V-shaped teeth formed on one side of a central portion of an upper end portion thereof. Distribute the edges into three places and collect. Next, FIG.
As shown in (a), the negative electrode current collector 2 is placed on the upper end of the power generating element 1 and the edges of the negative electrodes 1a divided by the jig are arranged on the holding portions 2c of the current collecting portion 2a. Insert each in the gap. Then, a portion other than the window 2e of one copper plate of each holding portion 2c is swaged between the other copper plate. The caulking operation is performed by inserting attachments of a caulking tool from above into both sides of each holding portion 2c and applying force so as to crush the two copper plates. Further, as shown by an arrow A in FIG. 2, ultrasonic welding is performed between a portion other than the window portion 2e of one of the copper plates of each of the holding portions 2c and the other copper plate, and as shown by an arrow B in FIG. Then, ultrasonic welding is also performed between the window portion 2e of one copper plate of each holding portion 2c and the other copper plate. Ultrasonic welding is performed by inserting attachments of an ultrasonic welder from both sides of each holding portion 2c from above and applying ultrasonic vibration to two copper plates. However, in a portion other than the window portion 2e of one of the copper plates indicated by the arrow A, the two thick copper plates are caulked and the edge of the negative electrode 1a is welded between the two copper plates. Welding is performed, and the thin copper foil on the edge of the negative electrode 1a is directly welded to the window 2e of one copper plate shown by the arrow B, so that ultrasonic welding with limited power is performed.

In the drawings, for simplicity, the negative electrode 1a, the positive electrode 1b, etc. of the power generating element 1 are coarsely wound with a small number of windings. In the gaps between the holding portions 2c of the electric portion 2a, a large number of the edge portions of the negative electrode 1a are held and connected and fixed.

A positive electrode current collector 3 not shown in FIG.
Similarly to the negative electrode current collector 2, a plurality of the portions where the aluminum foil is exposed at the edge of the positive electrode 1 b protruding from the lower end of the power generating element 1 are collectively inserted into the gap of the holding portion 3 c of the current collector 3 a. Then, a portion other than the window of one aluminum plate is caulked and ultrasonically welded, and the window of one aluminum plate is ultrasonically welded and fixedly connected.

According to the above configuration, the window 2e is formed in a part of one of the metal plates of the holding portions 2c, 3c in the current collectors 2a, 3a of the negative electrode current collector 2 and the positive electrode current collector 3. The negative electrode 1a and the positive electrode 1b sandwiched by the holding portion through the window portion
By directly ultrasonic welding the plurality of edge portions, it is possible to securely weld and connect and fix, and there is no danger that the battery characteristics will decrease with use.
In addition, the portions other than the window portion 2e of one of the metal plates of the sandwiching portions 2c, 3c are also caulked and ultrasonically welded to form the negative electrode 1a or the positive electrode 1a.
b can hold the plurality of edges firmly.

In the above embodiment, the power generating element 1 wound in a long cylindrical shape has been described, but the present invention can be similarly applied to other wound power generating elements. However,
For example, in the case of a cylindrical power generating element, the current collectors 2a and 3a
Are formed to be curved along the winding of the negative electrode 1a and the positive electrode 1b.

In the above embodiment, the non-aqueous electrolyte secondary battery has been described. However, the present invention can be applied to other batteries in general. Furthermore, in the above embodiment, the case where a copper plate and an aluminum plate are used for the negative electrode current collector 2 and the positive electrode current collector 3 has been described. However, other metal plates can be used according to the type of battery.

Further, in the above embodiment, the negative electrode current collector 2
And the case where the sandwiching portions 2c, 3c of the positive electrode current collector 3 are caulked and ultrasonically welded has been described. If so, laser welding or the like can be used.

[0026]

As is apparent from the above description, according to the battery of the present invention, since the window is formed in one of the metal plates of the holding portion, a plurality of sheets sandwiched by the holding portion through the window are provided. The edges of the electrodes can be securely welded and fixed by welding, and the battery characteristics do not deteriorate with use due to insufficient electrical connection.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a perspective view showing a negative electrode current collector connected and fixed to a power generation element.

FIG. 2 illustrates one embodiment of the present invention, and is a partially enlarged perspective view showing an enlarged current collector of a negative electrode current collector.

FIG. 3 is a perspective view showing a configuration of a power generating element of the non-aqueous electrolyte secondary battery.

FIG. 4 is a perspective view showing a conventional example and showing a configuration of a negative electrode current collector and a positive electrode current collector.

FIG. 5 is a perspective view showing a conventional example and showing a negative electrode current collector connected and fixed to a power generating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation element 1a Negative electrode 1b Positive electrode 1c Separator 2 Negative electrode current collector 2a Current collection part 2b Terminal connection part 2c Holding part 2d Flat plate part 2e Window part

Claims (2)

[Claims] 1. A plurality of holding portions, which are formed by folding a substantially vertical metal plate at a top portion so that two metal plates face each other via a gap opened at a base side, and adjacent to these holding portions. Current collector of a current collector consisting of a flat plate portion that connects the base members to each other by a flat metal plate on the base side, and the band-like positive and negative electrodes are respectively shifted in the winding axis direction and wound via a band-like separator. Both ends of the winding type power generating element are disposed with their bases facing the both ends of the winding shaft, and the edges of the positive and negative electrodes protruding at both ends of the winding shaft of the power generating element are respectively located near the current collector. In the battery which is sandwiched between the holding portions of the current collector and fixedly connected by welding, a window portion communicating with a part of one metal plate of each holding portion in the current collector of the current collector and a gap between the other metal plate A battery, wherein a battery is formed. 2. An end edge of the electrode is inserted and caulked between two metal plates of a sandwiching portion of a current collector, and between the window of one metal plate and the other metal plate, and 2. The battery according to claim 1, wherein a portion other than the window of one of the metal plates and the other metal plate are connected and fixed by ultrasonic welding.