JP2000156240A - Battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disperse the flexure of an electrode to reduce a clearance between electrodes and to prevent the lowering of battery capacity by inserting a plate- shaped article bent in a wave-like form along the axis direction of a rolling axis in the rolling axis space at the rolling center part of a rolled generation element composed by rolling band-like positive and negative electrodes into a generally elongate cylindrical shape through a band-like separator. SOLUTION: A waved plate core 5 is inserted into a rolling axis space A formed in the rolling center part of a generation element 1. The waved plate core 5 is formed into a waved plate-like shape by bending, repeatedly by several cycles along the axis direction of the rolling axis into a waved shape (sinusoidal wave shape), a plate material having nearly the same width (the depth direction of the rolling axis space A) as a positive electrode 1a and a negative electrode 1b. The edges of the waved plate core 5 are prevented from being erected by bending inward each of both its ends in the lengthwise direction. Thereby, because the flexures of the positive electrode 1a and the negative electrode 1b are constrained in positions along the recesses of the waved plate core 5, a space between the electrodes is prevented from expanding.

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, and a method of manufacturing the battery.

[0002]

2. Description of the Related Art A configuration example of a large-capacity, large-capacity non-aqueous electrolyte secondary battery having a long cylindrical winding type power generating element 1 will be described.
As shown in FIG. 14, the power generating element 1 has a band-shaped positive electrode 1.
a and a negative electrode 1b are wound into a long cylindrical shape via a band-shaped separator 1c. By winding the positive electrode 1a and the negative electrode 1b slightly up and down, respectively, the lower end of the power generating element 1 Only the lower edge of the positive electrode 1a is projected,
Only the upper edge of the negative electrode 1b protrudes from the upper end. The separator 1c includes the positive electrode 1a and the negative electrode 1a.
It is wound so as to cover the portion where b overlaps, but not to cover the upper and lower edges.

[0005] As shown in FIGS. 15 and 16, the power generating element 1 is housed in a long cylindrical battery case 2. The battery case 2 includes a battery case body 2a in the shape of a long cylindrical container and a lid 2b in the shape of an oblong plate. And the power generation element 1
The battery case body 2 is housed in the battery case body 2a.
The inside is hermetically sealed by fitting the lid 2b into the opening at the upper end of a and welding the periphery. At this time, current collectors 3, 3 are connected and fixed to the positive electrode 1a and the negative electrode 1b of the power generating element 1, and the upper ends of the terminals 4, 4 connected and fixed to these current collectors 3, 3 are connected to the lid 2b. A glass hermetic seal or a ceramic hermetic seal is passed through the opening from below to insulate and fix it.

In the non-aqueous electrolyte secondary battery having the above-described structure, the positive electrode 1a and the negative electrode 1b repeatedly expand and contract with charge and discharge. In particular, in the case of a large-capacity and large-capacity battery, as shown in FIG. In order to absorb the increase in volume during expansion, it is necessary to leave a hollow winding space A in the center of the winding. However, in the case of the long cylindrical battery case 2, the positive electrode 1 a and the negative electrode 1
When b is inflated, the flat portion of the side surface may be bent outward to absorb the increase in volume during the inflation. However, in the case where a plurality of batteries are closely arranged on the flat side surface of the battery case 2 and used as an assembled battery, or when a heat sink is used in close contact with the flat side surface of the battery case 2,
Since this flat side cannot be bent outward,
The winding space A is always required at the center of the winding of the power generating element 1. In FIG. 17, for ease of explanation, the number of turns of the positive electrode 1a and the negative electrode 1b is reduced, and the separator 1c is omitted (the same applies hereinafter).

[0005]

However, when the positive electrode 1a and the negative electrode 1b repeatedly expand and contract due to charge and discharge, the power generating element 1 does not always expand and contract uniformly.
In particular, in the curved portion of the winding, the winding of the positive electrode 1a and the negative electrode 1b gradually shifts, and as shown in FIG. 18, the winding of the positive electrode 1a and the negative electrode 1b becomes Deflection occurs. Moreover, the bending of the positive electrode 1a and the negative electrode 1b is such that the winding space A is located at the center of the winding, so that the bending toward the center becomes larger toward the winding space A. For this reason, in the conventional long cylindrical non-aqueous electrolyte secondary battery, as the charge / discharge cycle progresses, the positive electrode 1a and the negative electrode 1b of the power generation element 1 are wound in a linear portion in the winding direction, and the center portion becomes closer to the winding space A. To create a gap between the poles, so the internal resistance of this part increases,
There has been a problem that the battery capacity is reduced and the battery life is shortened.

Conventionally, in order to solve the above problem, as shown in FIG. 19, a case where a plate-shaped elastic core 7 made of silicone rubber or the like is inserted into the winding shaft space A of the power generating element 1 may be used. there were. However, in the nonaqueous electrolyte secondary battery, a highly reactive electrolyte is gasified in a large amount at the time of an abnormality. When the winding space A is closed by the elastic core 7 made of such an elastic body, there is no way for gas generated in various places inside the power generating element 1 to escape, so that there is a problem that safety is reduced. In addition, such an elastic core 7 must be inserted into the winding space A after removing the wound power generating element 1 from the winding shaft of the winding machine even in the manufacture of a battery. However, there has been a problem that the number of working steps increases, which leads to an increase in battery cost.

The present invention has been made in order to cope with such a situation, and the bending of the electrodes is dispersed by inserting a repeatedly bent plate-like material into the winding space of the power generating element, so as to disperse the gap between the electrodes. It is an object of the present invention to provide a battery which can reduce the battery capacity and prevent a decrease in battery capacity, and a method for manufacturing the battery.

[0008]

According to a first aspect of the present invention, there is provided a battery including a winding type power generating element in which band-shaped positive and negative electrodes are wound in a substantially long cylindrical shape via a band-shaped separator. A plate-like material bent into an uneven shape along the direction of the winding axis is inserted into the winding shaft space at the center of the winding.

According to the first aspect of the present invention, since the plate-like material bent into an uneven shape is inserted into the winding space of the power generating element, even if the electrode repeatedly expands and contracts due to charging and discharging, it is bent. Since this bending is restricted to a position along the concave portion of the plate-like object,
It is possible to prevent the gap between the poles from being widened.

A second aspect of the present invention is characterized in that the plate-like object is repeatedly bent twice or more in an uneven shape.

According to the second aspect of the present invention, since the uneven bending of the plate-like object is repeated two or more times, the bending of the electrode is also dispersed at two or more places, and the gap between the poles at each bent portion is narrowed. Will be able to do it.

The invention according to claim 3 is characterized in that the uneven bending of the plate-like object has a waveform.

According to the third aspect of the present invention, since the uneven bending of the plate-like object has a waveform, the electrode is smoothly and smoothly bent along the waveform.

A fourth aspect of the present invention is characterized in that a battery case having an uneven surface on the inner surface synchronized with the uneven bending of the plate-like object is used.

According to the fourth aspect of the present invention, since the electrode is bent between the unevenness of the plate-like object and the unevenness of the battery case, the gap between the electrodes at the time of this bending can be further reduced.

The invention of a battery manufacturing method according to claim 5 is characterized in that the plate-shaped object is set as a core on a winding shaft, and a separator and positive and negative electrodes are wound to assemble a power generating element.

According to the fifth aspect of the present invention, since the plate-like object is set in advance on the winding shaft when the power generating element is wound, the step of inserting the plate-like object into the power generating element later can be omitted.

[0018]

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

1 to 13 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery, FIG. 2 is a perspective view of a corrugated sheet core, and FIG. FIG. 4 is a view for explaining a winding process of the power generating element, FIG. 4 is a longitudinal sectional plan view of the nonaqueous electrolyte secondary battery when the electrode is bent, FIG. 5 is a plan view of a corrugated sheet core, and FIG. 7 is a plan view of a corrugated core having a small amplitude at the center, FIG. 7 is a plan view of a corrugated core having a large amplitude at the center, FIG. 8 is a plan view of a triangular corrugated core, and FIG. FIG. 10 is a plan view of a corrugated core having corrugations of 1.5 cycles, FIG. 11 is a plan view of a corrugated core having irregularities of one cycle, and FIG. 12 is a battery. FIG. 1 is a vertical cross-sectional plan view of a nonaqueous electrolyte secondary battery in which unevenness is formed on the side surface of a case.
3 is a vertical cross-sectional plan view of the nonaqueous electrolyte secondary battery in a case where irregularities are formed only on the inner surface of the side surface of the battery case. Components having the same functions as those of the conventional example shown in FIGS. 14 to 19 will be described with the same reference numerals.

In the present embodiment, a large-capacity, large-capacity non-aqueous electrolyte secondary battery including a long cylindrical wound-type power generating element 1 will be described in the same manner as the conventional example shown in FIGS. The configuration of the power generating element 1 and the battery case 2 of the nonaqueous electrolyte secondary battery of the present embodiment is the same as that of the conventional example, and the current collectors 3 and 3 and the terminals 4 and 4 are similarly attached.

As shown in FIG. 1, a corrugated sheet core 5 is inserted into a winding space A formed at the center of the winding of the power generating element 1. As shown in FIG. 2, the corrugated sheet core 5 has substantially the same width as the positive electrode 1 a and the negative electrode 1 b (in the depth direction of the winding shaft space A).
Is repeatedly bent into a corrugated (sinusoidal) shape for several cycles along the winding axis direction to form a corrugated plate. The corrugated sheet core 5 is wound around both ends in the longitudinal direction so that the edge does not stand. Examples of the material of the corrugated sheet core 5 include a synthetic resin plate having an electrolytic solution resistance such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyimide (PI), and polyphenylene sulfide (PPS). A metal plate or the like having an electrolytic solution resistance such as aluminum or copper or an alloy material containing these as a main component is used. These synthetic resin plates, metal plates and the like may have some elasticity.

Here, in the conventional example shown in FIGS. 14 to 16, a current collector 3 of a positive electrode is connected and fixed to a lower edge of a positive electrode 1a protruding toward the lower end side of the power generating element 1, and The aluminum alloy plate constituting 3 was pulled out to the upper part through the side surface of the power generating element 1, and the positive electrode terminal 4 was connected and fixed thereto. However, when a metal material such as an aluminum alloy is used for the corrugated core 5, the positive electrode 1
The current collector 3 connected to a and the other current collector 3 disposed above the power generating element 1 by connecting and fixing the positive electrode terminal 4 can be connected through the corrugated core 5. become.

The corrugated core 5 may be inserted into the winding space A after the power generating element 1 whose winding has been completed is removed from the winding shaft of the winding machine, as shown in FIG. The winding core 6 is fitted in the winding shaft 6 of the winding machine in advance, the positive electrode 1a and the negative electrode 1b are wound together with the separator 1c (not shown), and then only the winding shaft 6 is removed. It can also be inserted into one winding shaft space A. That is, the winding shaft 6 of the winding machine is arranged in parallel in a line at a pitch of 波長 wavelength of the waveform of the corrugated sheet core 5, and the corrugated sheet core 5 is first placed in each concave portion of the corrugated sheet. It is fitted and set so that the winding shaft 6 is along. Next, after the separator 1c is wound several times around these winding shafts 6, the positive electrode 1a and the negative electrode 1b are sandwiched and wound in the direction of the arrow to create the power generating element 1. Then, if the power generating element 1 is taken out from the winding shaft 6 together with the corrugated sheet core 5 in the winding shaft space A, the step of inserting the corrugated sheet core 5 after the winding of the power generating element 1 can be omitted.

According to the above-structured non-aqueous electrolyte secondary battery,
Even if the positive electrode 1a and the negative electrode 1b bend due to expansion and contraction due to charge and discharge, as shown in FIG. 18 is distributed by the number of repetition cycles of FIG.
The gap between the positive electrode 1a and the negative electrode 1b, which occurs in each bent portion, can be made smaller than in the case where the large deflection shown in FIG.

Therefore, according to the present embodiment, even when the positive electrode 1a and the negative electrode 1b are bent, the gap between the electrodes at this portion is not excessively widened and the internal resistance is suppressed from increasing. In addition, it is possible to prevent the battery capacity from decreasing with the progress of the charge / discharge cycle and shortening the battery life. In addition, since the deflection of the positive electrode 1a and the negative electrode 1b follows the waveform of the corrugated sheet core 5, the variation in the deflection between the batteries is eliminated, and as a result, the variation in the battery performance is reduced. For this reason, when used as an assembled battery, it is possible to suppress performance degradation due to variations between batteries. In addition, since the corrugated core 5 inserted into the winding space A has a hollow shape in each recess, unlike the case where the solid elastic core 7 of the solid body shown in FIG. The generated gas can escape up and down from the winding space A.

In the above embodiment, as shown in FIG. 5, the corrugated core 5 having a constant amplitude of the corrugations has been described, but as shown in FIG. Alternatively, as shown in FIG. 7, it is also possible to use one having a larger amplitude at the center. Moreover, in the above embodiment, the case where the corrugated sheet core 5 is bent in a sine wave shape has been described. However, as shown in FIG. 8, the corrugated sheet core 5 may be bent in a triangular wave shape, or as shown in FIG. Can also be bent. That is, as long as the plate-like object is formed with an uneven bend along the length direction, the shape of the uneven shape is not limited. Also, both ends of the corrugated sheet core 5 do not necessarily need to be wound as in the above-described embodiment as long as the separator 1c and the like are not damaged.

Further, in the above-described embodiment, the case where the corrugations of the corrugated sheet core 5 is repeated for several cycles has been described. However, as shown in FIG. It is also possible. In this case, since the bending of the positive electrode 1a and the negative electrode 1b is divided into two portions on one side (the lower side in the figure) of the corrugated sheet core 5, the gap between these electrodes can be narrowed. However, corrugated sheet core 5
On the other side (upper side in the figure), there is only one flexure as in the conventional example shown in FIG. However, since the bending at both ends of the linear portion of the winding is restricted by the convex portions on both sides of the corrugated sheet core 5, it is possible to prevent a large gap between the poles at the bending portion. In addition, corrugated sheet core 5
As shown in FIG. 11, it is also possible to use a structure in which unevenness is repeated only for one cycle. In this case, the bending of the positive electrode 1a and the negative electrode 1b is not divided, but the bending position can be shifted to the concave portion on either side of the corrugated sheet core 5, thereby narrowing the gap between the electrodes. be able to.

Further, in the above embodiment, the battery case 2
Although the case where the portion other than the curved portion on the side surface of the (battery case main body 2a) has a flat plate-like long cylindrical shape has been described, as shown in FIG. It can also be formed in a concavo-convex shape in synchronization with the concavo-convex bending. By doing so, the positive electrode 1a and the negative electrode 1b bend along both the unevenness of the corrugated core 5 and the unevenness of the side surface of the battery case 2, so that the gap between the electrodes due to this bending is further narrowed. Will be able to do it. At this time, the outer surface of the battery case 2 may be made uneven like the inner surface.
As shown in FIG. 3, only the inner surface may be uneven and the outer surface may be linear.

Further, the width and the length of the corrugated sheet core 5 are not particularly limited.
It is sufficient that the length is within the range of 00%.
Is at least 50% or more and may be a size that can be accommodated in the battery case 2.

Further, in the above embodiment, the power generating element 1 wound in a long cylindrical shape has been described. However, the power generating element 1 is wound in a circular or elliptical shape and then compressed from both sides to obtain a long cylindrical shape or a shape close to a long cylindrical shape. The same can be applied to the power generating element 1 described above. In addition, the present invention can be similarly applied to a case where the power generating element 1 wound in an elliptical shape or a substantially long cylindrical shape similar thereto is used as it is. Further, the winding shaft 6 of the winding machine used for winding the power generating element 1 may be of any shape such as a plate shape, a diamond shape, etc., in addition to a pin shape. Further, in the above embodiment, the non-aqueous electrolyte secondary battery has been described. However, the present invention can be similarly applied to other batteries as long as the battery includes a wound power generating element 1 wound in a substantially long cylindrical shape. It is.

[0031]

As is apparent from the above description, according to the battery of the present invention and the method of manufacturing this battery, the deflection of the electrode due to charging and discharging is restricted to the position along the concave portion of the plate-like object. In addition, it is possible to prevent the gap between the poles from becoming wide.
In addition, by repeating the uneven bending of the plate-like object two or more times, the bending of the electrode can be dispersed at two or more places, and the gap between the electrodes at each bent portion can be narrowed. Therefore, an increase in the internal resistance at the bent portions of these electrodes is suppressed, so that a decrease in battery capacity due to the progress of the charge / discharge cycle can be prevented, and the battery life can be prolonged. In addition, the gasket space generated when an abnormality occurs can be passed through the winding shaft space into which the plate-shaped object is inserted, so that the safety of the battery can be improved. Also, when the battery is manufactured, if the plate is set on a winding shaft in advance during winding, the step of inserting the plate later can be omitted.

[Brief description of the drawings]

FIG. 1, showing one embodiment of the present invention, is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery.

FIG. 2, showing one embodiment of the present invention, is a perspective view of a corrugated sheet core.

FIG. 3, showing an embodiment of the present invention, is a view for explaining a winding step of a power generating element.

FIG. 4 illustrates one embodiment of the present invention, and is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery in which an electrode is bent.

FIG. 5, showing an embodiment of the present invention, is a plan view of a corrugated sheet core.

FIG. 6, showing an embodiment of the present invention, is a plan view of a corrugated core having a small amplitude at a central portion.

FIG. 7, showing an embodiment of the present invention, is a plan view of a corrugated sheet core having a large amplitude at a central portion.

FIG. 8, showing one embodiment of the present invention, is a plan view of a triangular corrugated core.

FIG. 9, showing an embodiment of the present invention, is a plan view of a trapezoidal corrugated core.

FIG. 10, showing an embodiment of the present invention, is a plan view of a corrugated sheet core having irregularities of 1.5 cycles.

FIG. 11, showing one embodiment of the present invention, is a plan view of a corrugated sheet core having one cycle of unevenness.

FIG. 12 illustrates one embodiment of the present invention, and is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery in which unevenness is formed on a side surface of a battery case.

FIG. 13 illustrates one embodiment of the present invention, and is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery in which unevenness is formed only on the inner surface of the side surface of the battery case.

FIG. 14 is a perspective view illustrating the structure of a power generation element of a nonaqueous electrolyte secondary battery.

FIG. 15 is a perspective view illustrating the structure of a non-aqueous electrolyte secondary battery.

FIG. 16 is an overall perspective view of a non-aqueous electrolyte secondary battery.

FIG. 17 shows a conventional example, and is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery.

FIG. 18 illustrates a conventional example, and is a vertical cross-sectional plan view of a nonaqueous electrolyte secondary battery in which an electrode is bent.

FIG. 19 shows a conventional example, and is a longitudinal sectional plan view of a nonaqueous electrolyte secondary battery in which an elastic core is inserted into a winding shaft space.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation element 1a Positive electrode 1b Negative electrode 1c Separator 5 Corrugated core

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takefumi Inoue 1 Kinoshoin Nishinosho, Minami-ku, Kyoto Ino Babacho, Japan Within (72) Inventor Takahiro Shizuki Nishinosho, Kichijoin, Minami-ku, Kyoto No. 1, Inono Babacho, Japan Battery Co., Ltd. (72) Inventor Hideki Masuda, No. 1, Nishinosho, Kisho-in, Minami-ku, Kyoto, Japan

Claims (5)

[Claims] 1. A battery provided with a winding type power generating element in which a band-shaped positive and negative electrode is wound in a substantially long cylindrical shape via a band-shaped separator, wherein a winding shaft space at the center of the winding of the power generating element is provided. A battery, wherein a plate-like material bent into an uneven shape along the winding axis direction is inserted. 2. The battery according to claim 1, wherein the irregular bending of the plate-like object is repeated twice or more. 3. The battery according to claim 1, wherein the uneven bending of the plate-like object has a waveform. 4. The battery according to claim 1, wherein a battery case having an uneven surface on the inner surface synchronized with the uneven bending of the plate-like object is used. 5. A power generating element is assembled by setting the plate-shaped object according to claim 1 as a core on a winding shaft and winding a separator and positive and negative electrodes. Battery manufacturing method.