JP2009152031A - Cylindrical battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical battery of which the open port of a battery case is sealed by an insulative packing and in which a liquid leak resistance at a high temperature use is improved. <P>SOLUTION: In the cylindrical battery, a sealing material of a butyl rubber base is formed between an insulative packing and an battery case and between the insulative packing and a sealing plate so that a curvature radius continuing from a highest point of the battery case after sealing to an open port end portion of the battery case may be equal or less than a curvature radius continuing from the highest point of the battery case after sealing to an upper rising-up portion of a stepped portion, and as a result, the liquid leak resistance at a high temperature use is improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cylindrical battery.

  A lithium manganese dioxide battery using metallic lithium or a lithium alloy as a negative electrode active material and manganese dioxide as a positive electrode active material has high voltage and high energy density, low self-discharge, and extremely long shelf life. In recent years, demand has expanded rapidly and has been used in many electronic devices. The operating temperature range of the lithium manganese dioxide battery is wide from 60 ° C. to −40 ° C., so that it is widely used mainly as a film-type camera battery. Recently, taking advantage of excellent performance, there is a demand for use in automobiles, industrial equipment and the like that require a wide use temperature range from 85 ° C. to −40 ° C.

  In this type of conventional cylindrical battery, an annular step is formed by projecting the vicinity of the opening of a bottomed cylindrical battery case filled with a power generation element to the inside, and the sealing plate is sandwiched between the inner edges of the insulating packing The assembled sealing body is placed on the step of the battery case, and the opening end of the battery case is folded inward so that the insulating packing is sandwiched between the step of the battery case and the opening of the folded case. The thing of the structure of compressing and sealing up and down between the made sealing plates is known.

Patent Document 1 discloses that it is effective to use an asphalt-based or olefin-based sealant to enhance the sealing effect between the insulating packing and the battery case, and the asphalt softens when used at high temperatures. Therefore, it is considered that sealants such as olefin-based butyl rubber are excellent.
Japanese Patent Laid-Open No. 2000-200590

  Then, when the cylindrical battery was produced using the butyl rubber type sealing agent shown by patent document 1, sufficient sealing effect was not acquired in the high temperature range of 85 degreeC, but not only sealing agent. The sealing structure was found to be important. As a countermeasure, it is considered that the rebound elastic force of the insulating packing is improved and the sealing effect is enhanced by reducing the radius of curvature that continues from the rising portion above the stepped portion of the battery case after sealing to the opening end. However, in the above method, the area for compressing the insulation packing is reduced in the portion that continues from the maximum point of the battery case height after sealing to the rising portion above the stepped portion, and there is a gap between the insulation packing and the battery case. There arises a problem that the sealing performance is impaired.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a cylindrical battery having high sealing performance and improved leakage resistance.

  In order to solve the above-described problems, the present invention provides an assembly in which a cylindrical battery case filled with a power generation element is protruded inward to form an annular stepped portion, and a sealing plate is sandwiched between inner edges of the insulating packing. In a cylindrical battery in which a sealing body is placed on the step of the battery case, and the opening end of the battery case is folded inward and sealed, between the insulating packing and the battery case, and the insulating packing A butyl rubber-based sealant is formed between the sealing plates, and the radius of curvature that continues from the maximum point of the battery case height after sealing to the opening end of the battery case is equal to the height of the battery case after sealing. It is characterized by being formed with a radius of curvature equal to or less than the radius of curvature that extends from the maximum point to the rising portion above the stepped portion.

  According to the present invention, the radius of curvature that continues from the maximum point of the battery case height after sealing to the opening end of the battery case is from the maximum point of the battery case height after sealing to the rising portion above the stepped portion. By being formed with a continuous radius of curvature or less, the impact resilience of the insulating packing is improved and the area to be compressed is increased, and a more excellent sealing effect is obtained.

  By reducing the radius of curvature connected to the opening end from the maximum height of the battery case after sealing, the insulating packing at the opening end of the battery case is strongly compressed in the vertical direction to improve the resilience elastic force. it can. Also, by increasing the radius of curvature that continues from the maximum height of the battery case after sealing to the rising part above the step part, the area for compressing the insulation packing is increased, so that not only in the vertical direction but also in the horizontal direction Can compress the insulation packing. In addition, even when stored at 85 ° C., leakage resistance can be further improved by using a butyl rubber-based sealant having a high sealing power.

  According to the present invention, a cylindrical battery excellent in leakage resistance can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of a cylindrical non-aqueous electrolyte battery of the present invention. In FIG. 1, a nickel-plated steel plate battery case 1 also serving as a negative electrode terminal includes a positive electrode 2 mainly composed of manganese dioxide and graphite, and a negative electrode 3 mainly composed of lithium metal via a polypropylene separator 4. A power generation element wound in a spiral is inserted. After inserting the power generation element into the battery case 1, the annular step 7 was formed by projecting the vicinity of the opening of the battery case 1 inward. A butyl rubber sealant was applied above the annular step 7. 5 is a sealing plate made of SUS444, and 6 is an insulating packing made of polypropylene that closes the opening of the battery case 1. A sealing plate 5 is sandwiched between inner edges of the insulating packing 6 via a butyl rubber-based sealant. After injecting an electrolytic solution in which 1 mol / l of lithium trifluoromethanesulfonate as a solute was dissolved in a 1: 1 mixed solvent of propylene carbonate and 1.2-dimethoxyethane into the battery case 1, the insulating packing 6 was attached to the battery case. 1 was placed on an annular step 7 formed by projecting the vicinity of the opening 1 inward, and the opening end of the battery case 1 was folded inward to seal it.

  The radius of curvature that continues from the maximum point of the battery case height after sealing to the opening end 8 of the battery case is R1, and from the maximum point of the battery case height after sealing to the rising portion 9 above the step portion 7. Let R2 be the continuous radius of curvature.

  FIG. 2 shows the upper part of the battery case after sealing the cylindrical battery of the present invention.

  A radius of curvature R1 continuous from the maximum point of the battery case height after sealing to the open end 8 of the battery case and a radius of curvature continuous from the maximum point of the battery case height after sealing to the rising portion 9 above the stepped portion 7 When both R2 are small, the insulating packing 6 is strongly compressed in the vertical direction at the opening end 8 of the battery case to improve the resilience elastic force of the insulating packing, but rises above the stepped portion 7 from the maximum point of the battery case height. Since the area for compressing the insulating packing is reduced in the portion 9, the sealing effect is reduced.

  On the other hand, the radius of curvature R1 continuous from the maximum point of the battery case height after sealing to the open end 8 of the battery case and the rising point 9 above the stepped portion 7 from the maximum point of the battery case height after sealing. When both the curvature radii R2 are large, the area for compressing the insulation packing increases from the maximum point of the battery case height at the rising portion 9 above the stepped portion 7, but the insulation packing 6 is provided at the opening end 8 of the battery case. Since it cannot be compressed strongly in the vertical direction and the rebound resilience is reduced, the sealing effect is reduced.

  Furthermore, the radius of curvature R1 connected to the opening end 8 of the battery case is increased from the maximum point of the battery case height after sealing, and the rising portion 9 above the step 7 from the maximum point of the battery case height after sealing. When the radius of curvature R2 is reduced, the insulating packing 6 cannot be strongly compressed in the vertical direction at the opening end 8 of the battery case, the rebound resilience is reduced, and the step from the maximum point of the battery case height is reduced. Since the area for compressing the insulating packing 6 is reduced at the rising portion 9 above the portion 7, the sealing effect is reduced.

  Therefore, the radius of curvature R1 connected to the opening end 8 of the battery case is reduced from the maximum point of the battery case height after sealing, and the rising portion 9 above the step 7 from the maximum point of the battery case height after sealing. When the radius of curvature R2 is increased, the insulating packing 6 at the opening end 8 of the battery case is strongly compressed in the vertical direction to improve the rebound resilience, and the upper portion of the step 7 from the maximum point of the battery case height. Since the area for compressing the insulating packing is increased at the rising portion 9, there is an effect of improving the sealing force.

  Next, the method for sealing a cylindrical battery of the present invention will be specifically described. After inserting the power generation element into the inside of the battery case 1 using a nickel-plated steel plate, an annular step 7 that protrudes inward is formed near the opening of the battery case 1 by a roller as shown in FIG. .

  Next, a sealing agent 10 is applied to the inner surface side of the stepped portion 7 of the battery case 1 and the rising portion 9 thereabove, an electrolyte solution is injected into the battery case 1, and the insulating packing 6 into which the sealing plate 5 is inserted is then connected to the battery. It was placed on the step 7 of the case 1.

  Next, the opening end 8 of the battery case 1 was folded inward by the vertical movement of the sealing mold having a radius of curvature, and the CR2 size cylindrical battery shown in FIG. 1 was manufactured.

Example 1
The curvature radius R1 connected to the opening end 8 of the battery case from the maximum point of the battery case height after sealing is set to 0.8 mm, and the rising portion above the stepped portion 7 from the maximum point of the battery case height after sealing. A cylindrical battery having a curvature radius R2 continuous to 9 at 1.2 mm and using a butyl rubber system as the sealant 10 was designated as battery A.

(Comparative Example 1)
A battery was fabricated in the same manner as the battery of Example 1 except that asphalt was used as the sealant 10. This battery was designated as battery B.

(Comparative Example 2)
The curvature radius R1 connected to the opening end 8 of the battery case from the maximum point of the battery case height after sealing is set to 0.8 mm, and the rising portion above the stepped portion 7 from the maximum point of the battery case height after sealing. A battery was made in the same manner as the battery of Example 1, except that the radius of curvature R2 continuous to 9 was 0.8 mm. This battery was designated as battery C.

(Comparative Example 3)
The curvature radius R1 connected to the opening end 8 of the battery case from the maximum point of the battery case height after sealing is set to 1.2 mm, and the rising portion above the stepped portion 7 from the maximum point of the battery case height after sealing. A battery was made in the same manner as the battery of Example 1, except that the radius of curvature R2 continuous to 9 was 0.8 mm. This battery was designated as battery D.

(Comparative Example 4)
The curvature radius R1 connected to the opening end 8 of the battery case from the maximum point of the battery case height after sealing is set to 1.2 mm, and the rising portion above the stepped portion 7 from the maximum point of the battery case height after sealing. A battery was made in the same manner as the battery of Example 1 except that the radius of curvature R2 continued to 9 was made 1.2 mm. This battery was designated as battery E.

(Battery evaluation)
About the above battery A-battery E, the incidence rate of the liquid leakage at the time of performing the heat shock test which makes 85 degreeC 30 minutes and -40 degreeC 30 minutes 1 cycle is shown in Table 1. The number of tests was 100 each, and the number of cycles was 500.

  As can be seen from Table 1, the battery A according to the embodiment of the present invention has a small radius of curvature R1 connected to the open end 8 of the battery case from the maximum point of the battery case height after sealing, and the battery case after sealing. By increasing the radius of curvature R2 connected to the rising portion 9 above the step 7 from the maximum height point, the insulating packing 6 at the opening end 8 of the battery case is strongly compressed in the vertical direction, and the resilience elastic force is improved. Furthermore, since the area for compressing the insulating packing 6 increases at the rising portion 9 above the stepped portion 7 from the maximum point of the battery case height, the insulating packing 6 is compressed not only in the vertical direction but also in the horizontal direction. It is considered that there was an effect of improving the sealing force.

  Further, when the battery A and the battery B were compared, it was found that the sealing power of the butyl rubber-based sealant 10 was stronger than that of the asphalt-based. From the above points, the radius of curvature R1 connected to the opening end 8 of the battery case is reduced from the maximum point of the battery case height after sealing, and the point above the step 7 from the maximum point of the battery case height after sealing. By increasing the curvature radius R2 connected to the rising portion 9 and using the butyl rubber-based sealant 10 in combination, the leakage resistance when used in a high temperature range can be improved.

  The cylindrical battery of the present invention is useful as a battery for use in a high temperature range in automobiles, industrial equipment and the like.

Sectional drawing of the cylindrical battery concerning the Example of this invention Sectional drawing of the battery case upper part after sealing of the cylindrical battery of this invention Sectional view of a battery case with an annular step formed near the opening

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode 3 Negative electrode 4 Separator 5 Sealing plate 6 Insulation packing 7 Step part 8 Open end part 9 Standing part 10 Sealant

Claims (1)

A cylindrical battery case filled with a power generation element protrudes in the vicinity of the opening to form an annular stepped portion, and an assembly sealing body in which the sealing plate is sandwiched between the inner edges of the insulating packing is mounted on the stepped portion of the battery case. In the cylindrical battery formed by opening and sealing the opening end of the battery case inward, a butyl rubber-based sealant is provided between the insulating packing and the battery case and between the insulating packing and the sealing plate. The radius of curvature formed from the maximum point of the battery case height after sealing to the open end of the battery case is from the maximum point of the battery case height after sealing to the rising portion above the stepped portion. A cylindrical battery characterized by being formed with a continuous radius of curvature or less.

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