JP2010067379A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery wherein a caulking process of fixing a sealing body on the tip of a battery external can via a gasket is reviewed and the tip of the battery external can is hardly corroded. <P>SOLUTION: The sealed battery has the sealing body 18 which is liquid-tightly fixed on an opening of the battery external can 17 at an electrically insulated state with the battery external can 17 via the gasket 30a. The sealing body 18 is fixed on the opening of the battery external case 17 by caulking an opening end side of the battery external can 17. As a warped uphill section 31a at a pointed head side of the caulked opening end of the battery external can 17 is formed on the tip of the gasket 30a, a hollow is covered with a seal material by forming the hollow between the warped uphill section 31a and the tip of the caulked opening end of the battery external can, or the tip of the gasket 30a covers the tip of the caulked opening end of the battery external can. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealed battery, and more particularly to a sealed battery in which a caulking process for fixing a sealing body to a tip of a battery outer can through a gasket is reviewed so that the tip of the battery outer can is hardly corroded.

  In general, for sealed batteries such as non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries, nickel-cadmium secondary batteries, nickel-hydrogen secondary batteries, prismatic or cylindrical ones are produced. Has been. Among these, the general structure of the nonaqueous electrolyte secondary battery as a cylindrical sealed battery will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective view showing a cylindrical nonaqueous electrolyte secondary battery disclosed in Patent Document 1 below, cut in the vertical direction. FIG. 6 is an enlarged partial cutaway view of the sealing body of FIG.

  This nonaqueous electrolyte secondary battery 10 includes a wound electrode body 14 in which a positive electrode plate 11 and a negative electrode plate 12 are wound via a separator 13, and insulating plates 15 and 16 above and below the wound electrode body 14, respectively. Is placed in a steel cylindrical battery outer can 17 that also serves as a negative electrode terminal, and the current collecting tab 12a of the negative electrode plate 12 is welded to the inner bottom of the battery outer can 17 and the positive electrode plate 11 is collected. After the electric tab 11a is welded to the bottom plate portion of the sealing body 18 in which the safety device is incorporated, a predetermined nonaqueous electrolyte is injected from the opening of the battery outer can 17, and then the battery outer can is sealed by the gasket 30 and the sealing body 18. It is manufactured by sealing 17.

  The sealing body 18 includes a dish-shaped aluminum bottom plate 20 and a nickel-plated iron terminal cap 19 formed in an inverted dish shape. The bottom plate 20 has a concave portion 23 that bulges toward the inside of the battery, and a flat flange portion 24 that constitutes the bottom side portion of the concave portion 23, and a gas vent hole 23 a is provided at a corner portion of the concave portion 23. ing. An annular insulating gasket 27 made of, for example, PP is placed on the flange portion 24 of the bottom plate 20, and a safety valve 25 made of an aluminum foil composed of a recess 25 a and a flange portion 25 b is further mounted on the insulating gasket 27. However, the concave portion 25a of the safety valve 25 is placed on the concave portion 23 of the bottom plate 20, and the bottommost portion of the concave portion 23 of the safety valve 25 and the concave portion 23 of the bottom plate 20 are formed by, for example, ultrasonic welding. Are welded.

The terminal cap 19 has a convex portion 21 that bulges toward the outside of the battery, and a flat-plate-like flange portion 22 that constitutes the bottom side of the convex portion 21. A hole 21a is provided. Then, the terminal cap 19 is placed on the safety valve 25, laser welding is performed at a plurality of locations from the terminal cap 19 side, and the flange portion 24 of the bottom plate 20 is crimped to produce the sealing body 18 having a current blocking function. The Reference numeral 28 indicates a welding mark formed by laser welding. As shown in FIG. 5, the sealing body 18 is placed on the opening of the battery outer can 17 via a separate gasket 30, and then the opening end side of the battery outer can 17 is crimped, thereby It is liquid-tightly attached in a state of being electrically insulated from the outer can 17.
JP 2007-194167 A

  A nickel-plated iron plate in which iron is nickel-plated is used in an outer can used for such a cylindrical sealed battery. This nickel-plated iron plate has a weak point that when the nickel plating is peeled off due to some influence, the portion is susceptible to corrosion. In order to compensate for these weak points, contrivances such as post-plating have been made. In particular, the tip portion of the battery outer can is greatly bent in a caulking process for fixing the sealing body via a gasket, so that the nickel plating is likely to be peeled off. The nickel plating peeling part reacts with water and oxygen in the atmosphere and is easily corroded, and when it comes into contact with the electrolyte, the corrosion is further accelerated and discolored, which makes the battery user uncomfortable. The problem of giving

  The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to review a caulking process for fixing a sealing body to the tip of a battery outer can via a gasket, and to An object of the present invention is to provide a sealed battery in which the tip of the outer can is hardly corroded.

In order to achieve the above object, the sealed battery of the present invention comprises:
A battery outer can,
An electrode body housed in the battery outer can, and laminated or wound in a state where the positive electrode plate and the negative electrode plate are insulated from each other via a separator;
A sealing body that is liquid-tightly fixed in an electrically insulated state from the battery outer can through a gasket at an opening of the battery outer can;
With
In the sealed battery, the sealing body is fixed to the opening of the battery outer can by crimping the opening end side of the battery outer can.
The tip of the gasket has a dent between the tip of the crimped open end of the battery outer can by forming a warped part on the tip of the crimped open end of the battery outer can. It is formed, The inside of the said hollow is coat | covered with the sealing material, It is characterized by the above-mentioned.

  In the sealed battery of the present invention, the sealing body is fixed to the opening of the battery outer can by caulking the opening end side of the battery outer can, and the opening of the gasket outer can is crimped to the opening of the battery outer can A dent is formed between the end of the battery armored can and the open end of the battery outer can, and a sealing material is applied in the dent. In order to form a recess between the tip of the gasket and the tip of the crimped open end of the battery outer can, the length of the warped portion of the gasket is the tip of the battery outer can. It can be easily formed by making it longer than the thickness of the part. In the sealed battery of the present invention, since the inside of the recess is covered with the sealing material, the tip of the battery outer can becomes more difficult to touch the air, and the electrolyte may ooze out from the inside of the battery. Even if it exists, it becomes possible to hold | maintain sealing performance with a sealing material, and it becomes possible to suppress the corrosion of the front-end | tip part of a battery exterior can.

  A well-known thing can be used as a sealing material. Examples include rubber resins, alkyd resins, ester resins, acrylic resins and the like dissolved in organic solvents and water, and those that are cured by chemical changes such as silicone. The sealing material is in a liquid form, and is preferably applied to the dent and then dried or cured to change to a solid, so that the solid component adheres to the dent and is excellent in handling.

In order to achieve the above object, the sealed battery of the present invention is
A battery outer can,
An electrode body housed in the battery outer can, and laminated or wound in a state where the positive electrode plate and the negative electrode plate are insulated from each other via a separator;
A sealing body that is liquid-tightly fixed in an electrically insulated state from the battery outer can through a gasket at an opening of the battery outer can;
With
In the sealed battery, the sealing body is fixed to the opening of the battery outer can by crimping the opening end side of the battery outer can.
The front end of the gasket has a warped portion formed on the front end side of the crimped open end of the battery outer can, and covers the front end of the crimped open end of the battery outer can. To do.

  In the sealed battery of the present invention, the sealing body is fixed to the opening of the battery outer can by caulking the opening end side of the battery outer can, and the opening of the gasket outer can is crimped to the opening of the battery outer can It is made to warp to the tip side of the end. Such a configuration can be formed by the shape of the mold when the front end side of the battery outer can is swaged and sealed. According to the sealed battery of the present invention, since the tip of the battery outer can covers the tip of the gasket, even if the plating of the battery outer can is peeled off, the tip of the battery outer can is air. Therefore, it becomes difficult to come into contact with moisture and oxygen in the air, and corrosion of the tip of the battery outer can can be suppressed.

  The effects as described above can be obtained by providing a structure in which the tip of the gasket has a thickness, or by covering the tip of the gasket with the gasket that has been warped in advance as shown in FIG. It can also be achieved by forming the sealing body by caulking at the tip. However, considering the yield at the time of gasket production, the load force required at the time of sealing, the controllability of the gasket allowance from the tip of the outer can, and the possibility of the gasket breaking when caulked, etc. The gasket warpage is adjusted by adjusting the shape and dimensions of the crimping mold, and compressing the gasket that comes into contact with the outer can tip when the outer can tip presses the gasket in the caulking process. It is preferable to form so as to warp to the side.

  In the sealed battery of the present invention, it is preferable that the height of the gasket warp does not exceed the height of the crimped portion of the battery outer can.

  The assembled battery is processed into an assembled battery in a later process. At this time, a lead is welded to the terminal cap to connect the battery. And the insulating member which covers the crimping part of an outer can is attached so that the short which the welded lead and an outer can contact may not be raise | generated. Here, if the warped height of the gasket exceeds the height of the caulking portion, the insulating member may be lifted by the tip of the gasket and the holding may become unstable. If the height of the gasket warpage does not exceed the height of the caulking portion, the insulating member is not lifted and is stably held.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. However, the embodiment shown below is a sealing body 18 used in the conventional non-aqueous electrolyte secondary battery 10 shown in FIGS. 5 and 6 as a sealed battery for embodying the technical idea of the present invention. This is an example of the crimped portion on the opening end side of the battery outer can 17 using the battery, and is not intended to specify the present invention as the nonaqueous electrolyte secondary battery 10 using the sealing body 18. . That is, the present invention is equally applicable to various sealed batteries without departing from the technical idea shown in the claims, such as when a sealing body having another configuration is used, or a sealed battery using an aqueous electrolyte. It can be applied. 1 to 3, the same components as those of the conventional nonaqueous electrolyte secondary battery 10 and the sealing body 18 shown in FIGS. 5 and 6 will be described with the same reference numerals.

  1 is a partial cross-sectional view of a caulking portion of the sealed battery of Example 1. FIG. 2 is a partial cross-sectional view of a caulking portion of the sealed battery of Example 2. FIG. FIG. 3 is a partial cross-sectional view of a caulking portion of a sealed battery of a comparative example.

  In addition, the structure of the nonaqueous electrolyte secondary battery used by Examples 1-3 and the comparative example and the structure of a sealing body were shown in FIG.5 and FIG.6 except the structure of the caulking part of a gasket and a battery exterior can. Since it is the same as that of a thing, FIG.5 and FIG.6 is used and demonstrated.

  First, the thing of the structure similar to the sealing body 18 of the prior art example shown by FIG. 6 was prepared as a sealing body used by Examples 1-3 and a comparative example. Next, gaskets 30a (Examples 1 and 3), gaskets 30b (Example 2) and 30c (Comparative Examples) were prepared as gaskets used in Examples 1 to 3 and Comparative Examples. The gaskets 30a to 30c are all made of PP, and the length of the warped portions 31a and 31b of the gaskets 30a and 30b of Examples 1 to 3 after the caulking process is the thickness of the tip of the battery outer can 17. It is adjusted to be longer than this.

  And each gasket 30a-30c is mounted in the part of the constriction part 17a formed in the opening part vicinity of the battery exterior can 17, Furthermore, the flange part 24 of the said sealing body 18 touches this gasket 30a-30c. It placed so that it might touch. Next, as in the case of the conventional example, the tip of the battery outer can 17 is crimped using a mold (not shown), and the sealing body 18 is placed on the upper portion of the constricted portion 17a of the battery outer can 17 via gaskets 30a to 30c. Fixed in a liquid-tight state.

  In addition, the shape of the mold is adjusted so that the tip of the gasket is warped at the tip of the outer can in the caulking process. In the case of Examples 1 and 3, by adjusting the mold shape so that the angle formed by the sealing body and the outer can tip is increased, the warping angle of the gasket tip is increased with respect to the sealing body. At this time, in the case of Example 1 and Example 3, there is no gap between the tip of the battery outer can 17 and the warped part 31a of the gasket 30a, and the tip of the battery outer can 17 and the gasket 30a. In other words, a groove is formed between the upper surface of the tip of the battery outer can 17 and the warped portion 31a of the gasket 30a. On the other hand, in the case of Example 2, by adjusting the mold shape so as to reduce the angle formed by the sealing body and the outer can tip, the warping angle of the gasket tip becomes smaller than that of the sealing body. At this time, a gap (groove) is formed between the tip of the battery outer can 17 and the warped portion 31b of the gasket 30b, and the tip of the battery outer can 17 and the warped portion 31b of the gasket 30b are in close contact with each other. In other words, the tip of the battery outer can 17 is exposed in the groove. Further, in the case of the comparative example, by adjusting the mold shape so that the gasket tip cannot be warped, the gasket 30c has no warped portion so that the tip portion of the battery outer can 17 is exposed. It is in a state. A partial sectional view of this comparative example is shown in FIG.

  Next, in the case of Example 1 and Example 2, a rubber-based sealing material 32 is placed in a groove formed between the tip of the battery outer can 17 and the warped portions 31a to 31b of the gaskets 30a to 30b. Applied. A partial cross-sectional view of Example 1 in this state is shown in FIG. 1, and a partial cross-sectional view of Example 2 is shown in FIG. In addition, in the case of Example 3, since it has the same structure as the case of Example 1 except not having apply | coated the sealing material 32, illustration is abbreviate | omitted. The batteries manufactured in Examples 1 to 3 and the comparative example are lithium ion nonaqueous electrolyte secondary batteries. Each battery size is 18 mm in diameter × 65 mm in length, and the designed battery capacity is 1200 mAh. is there.

[Corrosion Resistance Test] After each of the batteries of Examples 1 to 3 and the comparative example obtained in this way were fully charged, 20 pieces were each 70 ° C. and 90% relative humidity. The corrosive state was measured by leaving it to stand under and visually observing the crimped portion of the battery outer can 17 on the first day and the tenth day. In addition, the corrosion state examined the number of things by which rust was recognized by the caulking part of the battery outer can 17 visually. The results are summarized in Table 1.

[Leakage resistance test]
In addition, each of the batteries of Examples 1 to 3 and the comparative example manufactured as described above was allowed to stand at 85 ° C. for 30 minutes and then at −20 ° C. for 30 minutes. The heat shock test was repeated for 30 days, and the corrosion state was detected by visually observing the crimped portion of the battery outer can 17 on the 10th and 30th days. In addition, the corrosion state examined the number of things by which rust was recognized by the caulking part of the battery outer can 17 visually. The results are summarized in Table 1.

  According to the results shown in Table 1 above, according to the batteries of Examples 1 and 2, both the corrosion resistance and the leakage resistance are very excellent, but the comparative batteries are inferior in the corrosion resistance and leakage resistance. I understand that Further, in the battery of Example 3, both the corrosion resistance and the liquid leakage resistance are better than the battery of the comparative example, but it is understood that the battery is inferior to the battery of Example 1. The battery of Example 1 and the battery of Example 3 are the same in that the tip of the battery outer can 17 is in close contact with the warped portion 31a of the gasket 30a, but the upper side of the tip of the battery outer can 17 is the same. In the groove formed between the gasket and the warped portion 31a of the gasket, the battery of Example 1 is covered with the sealing material 32, whereas the battery of Example 3 is not covered with the sealing material. Is different. For this reason, even if only the tip portion of the battery outer can 17 and the warped portion 31a of the gasket are brought into close contact with each other, a good effect is produced. However, between the upper end portion of the battery outer can 17 and the warped portion 31a of the gasket 30a. It can be seen that a better effect is achieved when the inside of the groove formed in is covered with a sealing material.

  On the other hand, in the battery of Example 2, a gap (groove) is formed between the tip of the battery outer can 17 and the gasket 30b, but the inside of the groove is covered with the sealing material 32. Since the front end portion of the outer can 17 is not exposed, it is recognized that a good effect was obtained as in the case of the battery of Example 1.

  As is clear from the description of FIGS. 1 and 2, it is preferable that the heights of the warped portions 31 a and 31 b of the gaskets 30 a and 30 b do not exceed the height of the crimped portion of the battery outer can 17. That is, even if an insulating member is attached so as to cover the crimped portion of the outer can so that the welded lead does not contact the outer can and cause a short circuit, the warped height of the gasket is higher than the crimped portion. Therefore, the insulating member can be stably held without being lifted.

  Further, in Examples 1 to 3 described above, the sealed battery using the sealing body for crimping the terminal cap and the safety valve with the bottom plate has been described. However, the gasket and safety valve are provided near the opening of the outer can where the electrode body is inserted. The effects of the present invention can also be achieved for a sealed battery or the like of a type in which a terminal cap is placed and these components are fixed in a liquid-tight manner by crimping the open end of the outer can.

3 is a partial cross-sectional view of a caulking portion of the sealed battery of Example 1. FIG. FIG. 4 is a partial cross-sectional view of a caulking portion of a sealed battery according to Example 2. It is a fragmentary sectional view of the crimping part of the sealed battery of a comparative example. It is a fragmentary sectional view which shows the state by which the curvature part was previously formed in the gasket. It is a perspective view which cut | disconnects the cylindrical nonaqueous electrolyte secondary battery of a prior art example to the vertical direction. FIG. 6 is an enlarged partial cutaway view of the sealing body of FIG. 5.

Explanation of symbols

10: Nonaqueous electrolyte secondary battery 11: Positive electrode plate 11a: Current collecting tab 12: Negative electrode plate 12a: Current collecting tab 13: Separator 14: Winding electrode body 15, 16: Insulating plate 17: Battery outer can 17a: Constriction portion 18: Sealing body 19: Terminal cap 20: Bottom plate 21: Convex part (terminal cap) 21a: Gas vent hole 22: Flange part (terminal cap) 23: Concave part 23 (flange part) 23a: Gas vent hole 24: Flange Portion 25: Safety valve 25a: Recessed portion (of safety valve) 25b: Flange portion (of safety valve) 27: Insulating gasket 28: Weld mark 30, 30a-30c: Gasket 31: Sealing material

Claims (3)

A battery outer can,
An electrode body housed in the battery outer can, and laminated or wound in a state where the positive electrode plate and the negative electrode plate are insulated from each other via a separator;
A sealing body that is liquid-tightly fixed in an electrically insulated state from the battery outer can through a gasket at an opening of the battery outer can;
With
In the sealed battery, the sealing body is fixed to the opening of the battery outer can by crimping the opening end side of the battery outer can.
The tip of the gasket has a dent between the tip of the crimped open end of the battery outer can by forming a warped part on the tip of the crimped open end of the battery outer can. A sealed battery characterized in that it is formed and the inside of the recess is covered with a sealing material. A battery outer can,
An electrode body housed in the battery outer can, and laminated or wound in a state where the positive electrode plate and the negative electrode plate are insulated from each other via a separator;
A sealing body that is liquid-tightly fixed in an electrically insulated state from the battery outer can through a gasket at an opening of the battery outer can;
With
In the sealed battery, the sealing body is fixed to the opening of the battery outer can by crimping the opening end side of the battery outer can.
The front end of the gasket has a warped portion formed on the front end side of the crimped open end of the battery outer can, and covers the front end of the crimped open end of the battery outer can. Sealed battery.   3. The sealed battery according to claim 1, wherein a height of warping of the gasket does not exceed a height of a caulking portion of the battery outer can. 4.

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