JP2002231215A - Weld-sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weld-sealed battery capable of improving reliability by preventing a tab from being cut in the battery inside even when vibration such as falling of the battery is applied. SOLUTION: This weld-sealed battery is provided with a spiral electrode 40, a battery exterior can 60, and a positive electrode collector tab 24 formed by forming an approximately U-shaped cutout 23 in a part of the spiral electrode 40 and raising the cutout, and the positive electrode collector tab 24, the battery exterior can 60, and a sealing lid 50 are welded together with the positive electrode collector tab 24 sandwiched between an opening edge of the battery exterior can 60 and the sealing lid 50. This battery is characterized in that a loose part 25 is provided in the positive electrode collector tab 24, and an adhesive tape 25 fixing the both and having electrolyte resistance is stuck to the positive electrode collector tab 24 and the outermost circumferential face 27 of the spiral electrode 40 opposed to a surface formed with the positive electrode collector tab 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and portable welded-sealed battery, and more particularly, to a shape of a sealing lid of a laser-sealed square ion battery, and more particularly to a structure of a current collecting tab of the laser-sealed square ion battery.

[0002]

2. Description of the Related Art As disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 9-171809, the present applicant discloses a portable small sealed battery having an opening edge (end) of a battery outer can in which a power generation element is housed. In FIG. 16A, the core 101 of either the positive electrode plate or the negative electrode plate is placed on the outermost periphery of the power generation element 106. After placing, and making a substantially U-shaped cut (cutting line) 102 in the exposed portion of the core body 101, FIG.
As shown in FIG. 17B, the cut 102 is folded in the direction of the opening of the battery outer can to form a current collecting tab 103. Thereafter, as shown in FIG. The three pieces were sandwiched between the edge 104a and the sealing lid 105, and in this state, the three pieces were sealed by laser welding.

In this case, when a shock such as a drop is applied to the battery and stress is applied to the current collecting tab, the current collecting tab 1
In order to prevent the current collecting tab 103 from being cut at the base portion 103a of 03 and increasing the internal resistance of the battery, the current collecting tab 103 and a part of the cut 102 are provided with a cut-prevention such as to cover them. The tape 107 was stuck.

As described above, the tape 107 for preventing cutting is used.
Is attached, the base portion 103 of the current collecting tab 103
It is possible to prevent the current collecting tab 103 from being cut at a. However, in this case, when a shock such as a drop is applied to the battery and stress is applied to the current collecting tab, the power generating element 106 tends to move downward (direction A in the figure) as shown in FIG. , The current collection tab 103 is pulled downward. For this reason, the current collecting tab 103 is cut off in the vicinity of the welded portion 108, which causes a new problem that the internal resistance of the battery increases.

In view of the above, a structure in which a slack portion 110 is provided on a current collecting tab 103 as shown in FIG. 19 has been proposed. However, such a structure can sufficiently cope with a case in which a vertical force (direction B in the drawing) acts, but a case in which a force in the horizontal direction (direction C in the drawing) acts or a twisting direction. It is not possible to sufficiently cope with the case where a force in the direction (D direction in the figure) acts, and there is a problem that the tab of the current collecting tab 103 is cut and the internal resistance of the battery increases.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned conventional problems, and applies vibrations such as dropping a battery to apply stress to a current collecting tab in any direction. The purpose of the present invention is to provide a welded-sealed battery that can prevent the current collector tab from being cut off even when added, and can suppress an increase in the internal resistance of the battery and improve reliability. And

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a spiral electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, and the spiral electrode body and electrolytic solution A battery outer can containing a liquid, and a substantially U-shaped cut is made in the exposed portion of the core of the positive electrode plate or the negative electrode plate located at the outermost peripheral portion of the spiral electrode body, and the cut is cut and raised to form the battery outer can. It has a current collecting tab formed by folding back in the opening side direction, and a sealing lid for closing the opening of the battery outer can, and the current collecting tab is provided with an opening edge of the battery outer can and the sealing lid. In a state sandwiched between
In the sealed battery having a structure in which the current collecting tab, the battery outer can, and the sealing lid are welded, the current collecting tab is provided with a slack portion, and the current collecting tab is formed from the slack portion of the current collecting tab. A reinforcing member having an electrolytic solution resistance for fixing the current collecting tab is attached to the outermost peripheral surface on the opposite side to the surface that has been formed.

With the above configuration, when vibration such as dropping the battery is applied, the battery is supported not only by the current collecting tab but also by the reinforcing member. That is, since the structure has a two-point support structure of the current collecting tab and the reinforcing member, the load is dispersed, and the impact on the current collecting tab is dispersed. As a result, even if stress is applied to the current collecting tab from any direction, it is possible to prevent the current collecting tab from being cut off by dispersing the impact on the current collecting tab. .

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the width of the reinforcing member is larger than the width of the current collecting tab. With the above configuration, the portion of the current collecting tab to which the reinforcing member is adhered is not exposed, so that there is also an effect that a short circuit in the battery can be suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a partial sectional view of a sealed battery according to the present invention.

As shown in FIG. 1, the welded-sealed battery of the present invention has a battery outer can 60 having a rectangular tube shape with a bottom. Inside the battery outer can 60, a positive electrode, a negative electrode, A flat spiral spiral electrode body 40 composed of an ion-permeable separator that separates the electrodes is housed. At the open end of the battery outer can 60, a sealing lid 50 having a negative electrode terminal 70 is provided.
Are welded, thereby sealing the battery. The outermost positive electrode core exposed portion 21 of the spiral electrode body 40
Is formed with a notch 23, and this notch 23
To form a positive electrode current collecting tab 24. The positive electrode current collecting tab 24 extends along the inner wall of the battery outer can 60 to the opening end of the battery, and the laser is held in a state of being sandwiched between the sealing lid 50 and the inner wall surface of the battery outer can 60. Welded.

Here, details of each constituent member of the above-mentioned sealed battery will be described below. FIG. 2A is a side view of the positive electrode plate used in the present invention, and FIG. 2B is a front view.
As shown in these figures, the positive electrode plate has a length of 335 mm, a width of 38 mm, and a thickness of 20 μm.
In principle, a positive electrode slurry 22 composed of polyvinylidene fluoride dissolved in LiCoO ₂ as a main component, other graphite, carbon black, and N-methyl-2-pyrrolidone is applied to both surfaces thereof, and the solvent is dried to a predetermined thickness. By compressing, a positive electrode active material layer 22 was formed. Then, the battery outer can 60
A substantially U- or U-shaped notch 23 is provided on the side of the outermost periphery when inserted or inserted.

It is to be noted that the positive electrode active material does not adhere to the portion of the positive electrode core body 21 where the cuts 23 are provided, and that the positive electrode active material adheres to the surface located closer to the battery can 60. The reason for not being provided is to achieve further electrical contact between the positive electrode core body 28 and the battery outer can 60.

FIG. 3A is a side view of the negative electrode plate used in the present invention, and FIG. 3B is a front view. As shown in these figures, the negative electrode plate was composed mainly of natural graphite powder on both sides of the copper foil of the negative electrode core body 31 having a length of 315 mm, a width of 39 mm and a thickness of 18 μm, and was dissolved in N-methyl-2-pyrrolidone. A negative electrode slurry made of polyvinylidene fluoride was applied, dried and compressed to a predetermined thickness, and a negative electrode current collecting tab 33 made of nickel was directly applied to a copper foil of a negative electrode core at a winding center portion described later. It is attached.

FIG. 4 is a sectional view showing the structure of the spiral electrode body 40 used in the present invention. As shown in the figure, a spiral electrode body 40 is formed by winding a positive electrode plate 20 and a negative electrode plate 30 via a polyethylene separator 41 which is slightly wider than both. In this case, the positive electrode plate 2
The spirally wound electrode body 40 is wound so that the one-side exposed portion on which no positive electrode active material is applied is located at the outermost peripheral portion of the spiral electrode body 40. Under this condition, an adhesive tape (not shown) is attached to the end of the winding, and the bottom is covered with an insulating tape (not shown) to prevent contact with the outer can 1.

FIG. 5 is a side view of a spiral electrode body 40 used in the present invention, FIG. 6 is a plan view of a main part of the spiral electrode body 40 used in the present invention, and FIG. 7 is a cross-sectional view of a main part of a sealed battery according to the present invention. It is. Here, the positive electrode current collecting tab 24 is formed by cutting and raising the cut portion 23 shown in FIG. 2, but when manufacturing the battery, as shown in FIG.
Is formed. As shown in FIGS. 5 and 7, one end of an adhesive tape (reinforcing member) 26 made of polypropylene slightly narrower than the positive electrode current collecting tab 24 is attached to the slack portion 25. Is attached to the outermost peripheral surface 27 of the spiral electrode body 40 opposite to the surface on which the positive electrode current collecting tab 24 is formed.

FIG. 8 is a half sectional view of the sealing lid used in the present invention,
FIG. 9 is a perspective view of the sealing lid used in the present invention as viewed obliquely from below. As shown in FIGS. 8 and 9, the sealing lid 50 includes a sealing plate 51 having a through hole near the center, a metal hollow cap 53 disposed in the through hole via an insulating gasket 52, Battery cap electrically connected to the upper end of hollow cap 53 (not shown, also serving as negative electrode external terminal)
And a current collecting terminal plate 54 electrically connected to the hollow cap 53, and an insulating plate 55 interposed between the sealing plate 51 and the current collecting terminal plate 54 to electrically insulate them.

The insulating gasket 52 and the insulating plate 5
5 and the current collecting terminal plate 54 are fixed to the sealing plate 51 by caulking the upper and lower ends of the hollow cap 53. Further, spacers 56 are arranged at both ends of the insulating plate 55. The spacer 56 is formed integrally with the insulating plate 55, and is disposed between the sealing plate 51 and the spiral electrode body 40, so that the spiral electrode body 40 does not swing in the vertical direction when a normal battery is used. Is to do so.
The current collecting terminal plate 54 is partially cut and raised in the downward direction, and the negative electrode current collecting tab 33 connected to the negative electrode core 31 described above is electrically connected to this portion.

The sealing lid 50 and the spiral electrode body 4
0, as shown in FIG.
A spacer 29 for preventing a short circuit with the spiral electrode body 40 is provided.

Here, a method of manufacturing the sealed battery having the above structure will be described with reference to FIGS. First, as shown in FIG. 10A, prevention of contact with the bottom of the battery outer can,
While the sealing lid 50 is located above the spiral electrode body 40 in which an adhesive tape is important for preventing unwinding and the like,
A notch 23 is formed in the outermost positive electrode core exposed portion 21 of the spiral electrode body 40. Next, as shown in FIG. 10B, the cuts 23 are cut and raised, and bent upward to form the positive electrode current collecting tabs 24. Next, as shown in FIG. 11A, after forming a slack portion 25 in the positive electrode current collecting tab 24, FIG.
As shown in FIG. 1B, the loosened portion 25 and the outermost peripheral surface 27 of the spiral electrode body 40 opposite to the surface on which the positive electrode current collecting tab 24 is formed are adhered with an adhesive tape 26.

Thereafter, the spiral electrode body 40 is inserted into a rectangular battery outer can 60 made of aluminum. At this time, the positive electrode current collecting tab 24 derived from the positive electrode plate 20 is
The sealing lid 50 is extended along the inner wall of the battery can to the opening end of the battery, and the upper end thereof is sandwiched between the outer peripheral side surface of the sealing lid 50 and the inner wall surface of the battery outer can 60.
Cover the opening edge. Thereafter, the fitting portion between the battery outer can 60 and the sealing plate 51 is irradiated with a laser beam to weld the portion to seal the battery. And, together with the positive electrode current collecting tab 24
And the battery outer can 60 are strongly connected electrically.

Further, the battery outer can 6
Then, a non-aqueous electrolyte is injected into the inside of the battery pack 0, and a battery cap is placed in the through hole. As a result, the sealed battery shown in FIG. 1 is manufactured. The embodiments of the present invention have been described above, but the present invention is of course not limited to these embodiments. That is, for example, the following may be performed.

(1) As shown in FIGS. 12 and 13, the adhesive tape 26 is configured to be wider than the width of the positive electrode current collecting tab 24, or as shown in FIGS. 14 and 15, the slack portion 25 is made larger. (Extends to the vicinity of the outermost peripheral surface 27 on the opposite side to the surface on which the positive electrode current collecting tab 24 is formed). (2) The adhesive tape is made of a material having resistance to organic electrolytes such as polyethylene, polyethylene terephthalate, and polyphenylene sulfide. (3) The current collecting tab is formed by the cut portion on the negative electrode side. (4) The dimensions and materials of the cores of the positive and negative electrodes are other values and materials. (5) The types of power generation elements of the battery are other.

[0024]

EXAMPLES (Examples) As examples, batteries manufactured by a method similar to the method described in the above embodiment of the present invention were used. The battery fabricated in this manner is hereinafter referred to as Battery A of the invention.

(Comparative Example) Except that the current collecting tab 103 was provided with a slack portion 110 as shown in FIG. A battery was manufactured in the same manner as in Example 1. The battery fabricated in this manner is hereinafter referred to as Comparative Battery X.

(Experiment 1) The number of defects when the battery A of the present invention and the comparative battery X were subjected to an impact was examined. The results are shown in Table 1. The experimental conditions were such that each battery was dropped onto concrete from a height of 1.5 m in a discharged state, and the number of drops was one time with each side (6 surfaces) of the battery facing the floor. Each set was set to drop one by one. Then, the internal resistance of the battery was measured for each set, and a case where the resistance fluctuated by 10 mΩ or more before and after the experiment was regarded as defective. The number of samples was 100 for each battery.

[0027]

[Table 1]

As a result, the comparative battery X was defective in 18 to 26 sets, whereas the battery A of the present invention was defective in 38 to 26 sets.
It was confirmed that no failure occurred up to 49 sets.

[0029]

As described above, according to the present description,
Even if vibration is applied such as dropping the battery and stress is applied to the current collection tab from any direction,
It is possible to prevent the current collecting tab from being cut off, suppress an increase in the internal resistance of the battery, and improve the reliability.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a sealed battery according to the present invention.

FIG. 2 is a configuration diagram of a positive electrode plate used in the present invention.

FIG. 3 is a configuration diagram of a negative electrode plate used in the present invention.

FIG. 4 is a diagram showing a configuration of a horizontal (horizontal) cross section of a spirally wound electrode body used in a welded sealed battery used in the present invention.

FIG. 5 is a side view of a spiral electrode body used in the present invention.

FIG. 6 is a plan view of a main part of a spiral electrode body used in the present invention.

FIG. 7 is a cross-sectional view of a main part of the sealed battery according to the present invention.

FIG. 8 is a half sectional view of a sealing lid used in the present invention.

FIG. 9 is a perspective view of a sealing lid used in the present invention as viewed obliquely from below.

FIG. 10 is an explanatory view showing a manufacturing process of the sealed battery according to the present invention.

FIG. 11 is an explanatory view showing a manufacturing process of the sealed battery according to the present invention.

FIG. 12 is a plan view of a sealed battery according to another example of the present invention.

FIG. 13 is an enlarged view of a main part of a sealed battery according to another example of the present invention.

FIG. 14 is an enlarged view of a main part of a sealed battery according to another example of the present invention.

FIG. 15 is an enlarged view of a main part of a sealed battery according to another example of the present invention.

FIG. 16 is an explanatory view showing a manufacturing process of a conventional sealed battery.

FIG. 17 is a partial cross-sectional view of a conventional sealed battery.

FIG. 18 is a cross-sectional view showing a state in which stress is applied to a conventional sealed battery.

FIG. 19 is a partial cross-sectional view of a sealed battery according to another conventional example.

[Explanation of symbols]

 20: Positive electrode plate 23: Cut portion 24: Positive electrode current collecting tab 25: Loose portion 26: Adhesive tape 30: Negative electrode plate 40: Spiral electrode body 41: Separator 50: Sealing lid 60: Battery outer can

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H022 AA09 AA18 BB02 CC12 CC16 CC21 5H029 AJ12 AJ14 AK03 AL07 BJ02 CJ03 CJ04 CJ05 DJ05 DJ07 HJ04

Claims (2)

[Claims] 1. A spiral electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, a battery outer can containing the spiral electrode body and an electrolyte, and an outermost peripheral portion of the spiral electrode body. A current collector tab formed by making a substantially U-shaped cut in the exposed portion of the core of the positive electrode plate or the negative electrode plate, cutting the cut and turning the cutout toward the opening side of the battery outer can,
A sealing cover for closing the opening of the battery outer can, and a collector tab and a battery in a state where the current collecting tab is sandwiched between the opening edge of the battery outer can and the sealing lid. In a welded sealed battery having a structure in which an outer can and a sealing lid are welded, a slack portion is provided in the current collecting tab, and a surface on which the current collecting tab is formed from the slack portion of the current collecting tab. A welded-sealed battery, wherein a reinforcing member having an electrolytic solution resistance for fixing a current collecting tab is attached to an outermost peripheral surface on the opposite side. 2. The sealed battery according to claim 1, wherein the width of the reinforcing member is larger than the width of the current collecting tab.