JP2008186712A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily visually discriminate the displacement of a laser light irradiation position with respect to a sealing plug, that is, the displacement of a welding spot by devising the sealing plug for sealing an electrolyte pouring hole of a sealed battery. <P>SOLUTION: On the upper surface 28 of the sealing plug 25, a marker 33 for confirming a position of a laser welding position is formed. This can allow a worker to easily visually discriminate the displacement of the welding spot only by confirming the relative position of a laser welding spot with respect to the sealing plug 25 through use of the maker 33. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealed battery in which an injection hole for supplying an electrolyte provided in a battery case or a lid plate that seals an opening of the battery case is hermetically sealed with a sealing plug.

  This type of sealed battery is known from Patent Document 1, for example. In that case, after injecting the electrolyte from the injection hole, a sealing plug is inserted into the injection hole, and then laser welding is performed over the entire periphery of the peripheral edge of the upper surface of the sealing plug and the upper peripheral edge of the injection hole. Thus, the injection hole is hermetically sealed. A sealed battery having a similar sealing structure can also be found in Patent Documents 2 to 4.

Japanese Patent No. 3652069 (see FIGS. 2 to 4) Japanese Unexamined Patent Publication No. 2000-21437 (see FIG. 2) JP 2002-358948 A (see FIG. 2) Japanese Patent Laying-Open No. 2006-40690 (see FIG. 2)

  The problem with a sealed battery having a sealing structure as described above is that if the irradiation position of the laser beam is misaligned, the weld location is displaced from the periphery of the upper surface of the sealing plug, resulting in poor welding, resulting in liquid leakage. Is to occur. More specifically, since the opening size of the injection hole and the outer dimension of the sealing plug are as small as several millimeters, the welding position is required to have extremely high precision in the order of several millimeters of the comma. For this reason, even if there is a slight deviation in the irradiation position of the laser beam, there is a risk that poor welding will occur.

  In the present situation, inspection work for welds is based on visual inspection by inspectors. That is, a visual inspection of the welded portion around the injection hole is performed on each battery, and a battery whose welding failure is confirmed by the inspection is extracted from the production line. However, since the diameter of the upper surface of the sealing plug is as small as several millimeters, it is not easy to visually confirm the weld location, and advanced skills are required before it can be determined in a short time whether or not there is a displacement. . For this reason, the inspection often becomes a bottleneck in the production line. In particular, when it is unavoidable that only an unskilled worker must carry out the inspection, the production efficiency of the production line may be significantly reduced. It was.

  The present invention has been made in order to solve the above-described problems, and by devising a sealing plug that seals the electrolyte injection hole of a sealed battery, laser light for the sealing plug can be obtained. The object is to make it possible to easily discriminate the positional deviation of the irradiation position, that is, the positional deviation of the welded portion, and thus to perform the visual inspection of the welding state in a shorter time.

  In the present invention, as shown in FIG. 2, the electrolyte solution supply injection hole 21 established in the battery case 2 or the lid plate 3 that seals the opening of the battery case 2 is hermetically sealed by a sealing plug 25. The target is a sealed battery. In this sealed battery 1, the sealing plug 25 and the battery case 2 or the cover plate 3 are integrated by laser welding the outer peripheral edge of the upper surface of the sealing plug 25 and the opening peripheral edge of the injection hole 21. Thus, the injection hole 21 is hermetically sealed. A marker 33 for confirming the position of the laser welding position is formed on the upper surface 28 of the sealing plug 25.

  Specific examples of the marker 33 include various shapes such as a linear shape, a dot shape, a circular shape, and a polygonal shape. These markers 33 may be formed by any method of forming a dent or projecting. The mark may be a printed mark. In short, as long as the rough position of the central portion or the outer peripheral portion of the upper surface 28 of the sealing plug 25 can be discriminated at a glance, the shape and the forming method are not limited. Absent.

  In particular, as shown in FIG. 3, a protrusion 36 integrally formed in a bulging upward direction is formed at the center of the upper surface 28 of the sealing plug 25, and the marker 33 is formed on the protrusion by pressing. It is preferable to form the groove 34 formed on the upper surface.

  As shown in FIG. 4, the marker 33 can be formed in a cross shape in plan view formed by combining two concave grooves 34. In this case, it is preferable that the cross-shaped intersection coincides with the center position of the upper surface 28 of the sealing plug 25 having a circular shape.

  As shown in FIG. 5, the marker 33 can be composed of a plurality of protrusions 42 protruding upward on the outer peripheral edge of the upper surface 28 of the sealing plug 25.

  According to the sealed battery of the present invention, since the marker 33 is formed on the upper surface 28 of the sealing plug 25, it is only necessary to confirm the relative position of the laser welding location with respect to the sealing plug 25 using the marker 33. Thus, it is possible to easily discriminate the positional deviation of the welded part visually.

  As a specific example, when the upper surface 28 of the sealing plug 25 has a circular shape and the laser beam is irradiated in a ring shape along the outer peripheral edge of the upper surface 28, the outline of the upper surface 28 is unclear by welding. Therefore, after performing the welding, it is likely that it is difficult to determine whether or not the welding location is displaced with respect to the sealing plug 25. On the other hand, if the marker 33 is formed on the upper surface 28 of the sealing plug 25 as in the present invention, the welded portion is misaligned with respect to the outer peripheral edge of the upper surface 28 using the marker 33. It is possible to easily determine whether or not.

  More specifically, for example, when the marker 33 is formed so that the center portion of the upper surface 28 can be specified, the center portion of the upper surface 28 specified by the marker 33 and the center portion of the ring-shaped welded portion It can be easily determined visually whether there is a gap between the two. In addition, when the marker 33 is formed so that the outer peripheral edge of the upper surface 28 can be specified, is there a deviation between the outer peripheral edge of the upper surface 28 specified by the marker 33 and the ring-shaped welding point? Whether or not can be easily determined visually.

  As described above, according to the present invention, it is possible to easily determine the position shift of the welded portion with respect to the sealing plug 25 by visual observation, so that the visual inspection of the welded state can be performed in a shorter time without requiring skill. This can be performed reliably, and it is possible to suppress the occurrence of inspection mistakes caused by inspection by unskilled inspectors, improve inspection accuracy, and contribute to product quality improvement. In addition, it is possible to solve the problem of a decrease in production efficiency of the production line due to the inspection delay.

  Since the sealing plug 25 has an outer dimension of several millimeters, it is extremely difficult to print and form the marker on the outer surface thereof with high positional accuracy. In that respect, when the marker 33 is formed by the concave groove 34 engraved on the upper surface of the protrusion 36 by press working, the concave groove 34 is simultaneously and integrally formed when the sealing plug 25 is press-molded. Therefore, the marker 33 is excellent in that it can be formed with high positional accuracy and without causing an increase in the cost of the sealing plug 25.

  The marker 33 is formed in a cross shape in plan view formed by combining two concave grooves 34 and 34, and the cross-shaped intersection is made to coincide with the center position of the upper surface 28 of the sealing plug 25 having a circular shape. Then, since the center position of the sealing plug 25 can be determined at a glance based on the crossing intersection of the marker 33, it is possible to easily determine the positional deviation of the welding portion with respect to the sealing plug 25 by visual observation. it can. Further, since the marker portion to be watched by the inspector becomes clear, it is excellent in that the inspection time can be shortened.

  When the marker 33 is composed of a plurality of protrusions 42 projecting upward on the outer peripheral edge of the upper surface 28 of the sealing plug 25, sealing can be performed simply by confirming the degree of breakage of these protrusions 42 after welding. It is possible to determine the positional deviation of the welded portion with respect to the plug 25. That is, when even one protrusion 42 is damaged, it can be determined that the irradiation position of the laser beam on the sealing plug 25 is shifted.

(First embodiment)
1 to 3 show a first embodiment of a sealed battery according to the present invention. The sealed battery 1 is a cylindrical battery having a cylindrical battery case 2 and a cover plate 3 that seals the upper surface opening of the battery case 2 as exterior elements. The electrode body 4 formed by spirally winding the positive electrode body 5 and the negative electrode body 6 with a separator interposed therebetween, and the electrolytic solution are accommodated. The battery case 2 and the cover plate 3 are made of stainless steel, and after the electrode body 4 is accommodated, the two 2 and 3 are fixed in an integrated manner by welding.

  In FIG. 2, reference numeral 9 indicates a positive electrode terminal connected to the positive electrode body 5 via the positive electrode lead 10, and the positive electrode terminal 9 has a rubber insulating packing 11 in the opening at the center of the lid plate 3. It is mounted in a penetrating manner. An insulating plate 12 is disposed below the lid plate 3. The insulating plate 12 includes a disk-shaped base portion 13 and inner and outer cylindrical walls 14 and 15 erected on the upper surface of the base portion 13, and a gas passage 16 is opened at the center of the base portion 13. Has been. Reference numeral 17 denotes a negative electrode lead connecting the inner surface of the battery case 2 and the negative electrode body 6.

  As shown in FIGS. 1 and 2, the lid plate 3 is provided with a partial arc-shaped pressure relief valve 20 in plan view and an injection hole 21 for injecting an electrolytic solution. The pressure release valve 20 is formed in a thin shape, and is cleaved when the battery internal pressure rises abnormally to release the pressure. The injection hole 21 is formed in a cylindrical shape, and a circular step portion 23 is formed in a stepped shape at the periphery of the opening (see FIG. 3).

  After injecting the electrolyte into the battery case 2 through the injection hole 21, the injection hole 21 is hermetically sealed with a sealing plug 25. The sealing plug 25 is a press-molded product made of stainless steel, and includes a cylindrical pin shaft 26 inserted into the injection hole 21 and a disc-shaped retaining portion 27 formed at the upper end of the pin shaft 26. Consists of. When the retaining portion 27 is fitted to the step portion 23 of the injection hole 21, the retaining portion 27 is received by the step portion 23, thereby preventing the sealing plug 25 from coming off from the lid plate 3. Yes.

  After the sealing plug 25 is inserted into the injection hole 21, laser welding is performed over the entire periphery (the entire periphery of the retaining portion 27) with respect to the peripheral edge portion of the upper surface 28 of the retaining portion 27 and the opening periphery of the injecting hole 21. By doing so, the injection hole 21 is hermetically sealed. As shown in FIG. 1, a ring-shaped melted portion 30 is formed at the weld location.

  On the upper surface 28 of the sealing plug 25, a marker 33 for confirming the position of the laser welding position is formed. In the present embodiment, the marker 33 is constituted by the concave groove 34 engraved on the upper surface 28 by press working. Specifically, a protrusion 36 that bulges upward is integrally formed at the center of the upper surface 28 of the sealing plug 25, and a concave groove 34 is formed on the upper surface of the protrusion 36. The concave groove 34 is formed so as to pass through the circular center of the circular retaining portion 27, that is, at a position that divides the protrusion 36 into two. Therefore, the center position of the upper surface 28 of the sealing plug 25 can be easily confirmed only by checking the marker 33 constituted by the concave groove 34.

  As described above, when the marker 33 is formed on the upper surface 28 of the sealing plug 25, the marker 33 can be used to check the relative position of the laser welding position with respect to the sealing plug 25. Since the misalignment can be easily determined visually, it is possible to perform the visual inspection of the welding state reliably in a shorter time without requiring skill. As a result, it is possible to suppress the occurrence of inspection mistakes caused by inspection by unskilled inspectors, improve inspection accuracy, and contribute to product quality improvement. In addition, it is possible to solve the problem of reduction in production efficiency of the production line due to the inspection delay.

  When the marker 33 is formed by the concave groove 34 engraved on the upper surface of the protrusion 36 by press working, the concave groove 34 can be formed simultaneously and integrally when the sealing plug 25 is press-molded. it can. According to this, it is excellent in that the marker 33 can be formed with high positional accuracy and without increasing the cost of the sealing plug 25.

(Second Embodiment)
In FIG. 4, the principal part of the sealed battery which concerns on 2nd Embodiment of this invention is shown. The marker 33 in this case is greatly different from the first embodiment in that the marker 33 is formed in a cross shape in a plan view formed by combining two concave grooves 34. The intersection of the grooves 34 and 34 coincides with the center position of the upper surface 28 of the sealing plug 25 having a circular shape. Since other configurations are substantially the same as those of the first embodiment, the same members are denoted by the same reference numerals, and the description thereof is omitted.

  According to this, since the center position of the sealing plug 25 can be determined at a glance based on the crossing point of the marker 33, it is possible to easily determine the positional deviation of the welded portion with respect to the sealing plug 25 visually. Can do. Further, since the marker portion to be watched by the inspector becomes clear, it is excellent in that the inspection time can be shortened.

(Third embodiment)
In FIG. 5, the principal part of the sealed battery which concerns on 3rd Embodiment of this invention is shown. In this case, the marker 33 is composed of a plurality of (four in the illustrated example) protrusions 42 protruding upward on the outer peripheral edge of the upper surface 28 of the sealing plug 25. These protrusions 42 are formed at radial positions at an equal angle (90 °) from the center of the upper surface 28. Further, the distances from the central portion of the upper surface 28 to the protrusions 42 are set equal. Since other configurations are substantially the same as those of the first embodiment, the same members are denoted by the same reference numerals, and the description thereof is omitted.

  According to this, it is possible to determine the positional deviation of the welding portion with respect to the sealing plug 25 only by confirming the degree of breakage of the protrusion 42 after welding. That is, when even one protrusion 42 is damaged, it can be determined that the irradiation position of the laser beam on the sealing plug 25 is shifted.

(Other embodiments)
In each of the above embodiments, the sealing plug 25 is configured by the cylindrical pin shaft 26 and the disc-shaped retaining portion 27 formed at the upper end of the pin shaft 26. It can also be formed so as to be tapered and tapered as a whole. In the second embodiment, the grooves 34 and 34 do not necessarily have to be orthogonal. Further, the marker 33 may be composed of a plurality of concave grooves 34 that are formed radially from the central portion of the upper surface 28 of the sealing plug 25 at equal intervals.

It is a top view which shows the principal part of the sealed battery which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the principal part of the sealed battery which concerns on 1st Embodiment. It is a figure which shows the shape of the sealing stopper which concerns on 1st Embodiment. It is a top view which shows the principal part of the sealed battery which concerns on 2nd Embodiment. It is a top view which shows the principal part of the sealed battery which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealed battery 2 Battery case 3 Cover plate 21 Injection hole 25 Seal plug 28 Top surface 33 of seal plug Marker

Claims (4)

An injection hole for supplying an electrolyte opened in a battery case or a lid plate that seals the opening of the battery case is a sealed battery that is hermetically sealed by a sealing plug,
By applying laser welding to the outer peripheral edge of the upper surface of the sealing plug and the opening peripheral edge of the injection hole, the sealing plug and the battery case or the lid plate are integrated to form the injection hole. It is designed to be hermetically sealed,
A sealed battery characterized in that a marker for position confirmation of a laser welding position is formed on the upper surface of the sealing plug. At the center of the upper surface of the sealing plug, a protrusion is integrally formed so as to bulge upward,
The sealed battery according to claim 1, wherein the marker is formed by a concave groove formed on the upper surface of the protrusion by press working. The marker is formed in a cross shape in a plan view formed by combining the two concave grooves,
The sealed battery according to claim 2, wherein the cross-shaped intersection coincides with a circular center position of the upper surface of the sealing plug having a circular shape.   2. The sealed battery according to claim 1, wherein the marker is composed of a plurality of protrusions protruding upward on an outer peripheral edge of the upper surface of the sealing plug.

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