JPH1083802A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery in which no crack is formed in the tack seal of the upper and lower shoulder parts even if stress is applied during the time of use by using a heat-shrinkable resin material having specified thickness, shrinking ratio in the height direction of a battery, and shrinking ratio in the radius direction for the tack seals. SOLUTION: This battery comprises a bottomed cylindrical battery can 1 housing electricity generating elements and a tack seal material made of a heat-shrinkable resin material and installed in the bottom part of the battery can l to cover a ring-like spacer material and a heat-shrinkable resin material having 30-80μm thickness, 40-60% of the shrinking ratio in the height direction of the battery, and 2-15% in the radius direction, resp., is used for the tack seal material. Consequently, a battery sufficiently durable to an impact from the outside and the load can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery in which a battery can containing a power generating element is covered with a heat-shrinkable resin.

[0002]

2. Description of the Related Art In recent years, the progress of electronics such as ICs and LSIs has been remarkable, and demand for primary and secondary batteries as power supplies for electronic precision equipment using these has been rapidly increasing. Conventionally, these batteries have used a metal jacket made of a thin metal plate having a design printed on its surface as an exterior material. The metal jacket requires a mechanical caulking process, and there is a problem that the actual capacity of the battery cannot be effectively used because the metal jacket is thick in order to increase the capacity of the battery.

In order to solve such a problem, a configuration is known in which the outer periphery of a battery can containing a power generating element is covered with a tubular heat-shrinkable resin (see, for example, Japanese Utility Model Application Publication No. SHO-5-58).
8-36326). However, when coating the battery can, it is necessary to shrink the resin after inserting the battery can into the tube of the heat-shrinkable resin cut to a predetermined length in advance, which causes a reduction in productivity.

[0004] Therefore, using a tack seal material obtained by applying a sticky / adhesive paste material to a heat-shrinkable resin film on which a metal is deposited, the surface of the battery is covered except for the terminals, and then the top and bottom of the tack seal material are heated. A method of shrinking the opening to insulate the upper and lower shoulders and side surfaces of the battery has been studied. In this method, a tack seal material using a heat-shrinkable resin is formed in a film shape, and after winding and covering the seal material on a battery can, the battery can is shrunk by heat to shrink the resin. There is no reduction in productivity due to the arrangement inside.

[0005] By the way, the shape of the terminal portion of a battery housed in a cylindrical battery can is such that one terminal portion protrudes by about 1 mm in order to distinguish between a positive electrode and a negative electrode or to prevent reverse connection to equipment. In general, the other pole is concave and the center is depressed. For this reason, the battery structure has a structure in which a cylindrical battery can that also serves as one terminal that houses the power generating element and a convex terminal plate that also serves as the other terminal are sealed via insulating packing, and the bottom of the battery can is A ring-shaped spacer is inserted, and the above-mentioned tack seal material is used as an exterior material.

[0006]

However, in the above-described conventional structure, when the battery is dropped, a crack is generated in a portion corresponding to the joint between the battery can and the ring-shaped spacer of the tack seal material. there were. This is a case in which the base material of the tack seal material is a heat-shrinkable resin film, and more specifically, the shrinkage direction is mainly a material only in the height direction of the battery, and corresponds to a joint portion between a battery can and a ring-shaped spacer. The two main causes are that the upper and lower parts of the part are thermally shrunk in a state of being fixed by an adhesive or an adhesive.

That is, when a tack seal material is coated on a battery can and a spacer, and the upper and lower openings of the tack seal material are thermally shrunk in the next step, a space corresponding to a joint portion between the battery can and the ring-shaped spacer is formed. A part is formed.
Therefore, in this portion, the battery can, the spacer and the tack seal material are not in an adhesive state, and only this portion shrinks during heat shrinkage, so that the battery is manufactured in a state where the tensile stress remains.

Therefore, when an external stress is applied to the battery, such as when the battery is dropped, a crack is generated in a portion of the tack seal material corresponding to the joint between the battery can and the ring-shaped spacer. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery and a battery exterior material in which a tack seal at upper and lower shoulders does not crack even when stress is applied during use of the battery. It is assumed that.

[0010]

In order to solve the above-mentioned problems, a battery according to the present invention comprises a bottomed cylindrical battery can that also serves as one terminal and houses a power generating element, and the other terminal. Then, a convex terminal plate that seals the opening of the battery can via the insulating packing, and a ring-shaped spacer having an outer diameter equal to or less than the outer diameter of the battery can and disposed at the bottom of the battery can. A battery in which a tack seal material made of a heat-shrinkable resin is attached and covered with a battery can and a spacer, and is appropriately shrunk in two directions, a height direction of the battery and a radial direction, as a base material of the tack seal material. A heat-shrinkable resin in the form of a film that shrinks at a predetermined rate is used.

[0011]

Embodiments of the present invention will be described below. The battery according to the present embodiment has a bottomed cylindrical battery can that also serves as one terminal that houses a power generating element, and a convex terminal plate that also serves as the other terminal is hermetically sealed through an insulating packing to form a ring. A battery in which the spacer is disposed at the bottom of the battery can and the battery can and the spacer are covered with a tack seal material made of a heat-shrinkable resin, wherein the tack seal material has a thickness of 30 to 80 μm, The battery is characterized by using a heat-shrinkable resin material having a shrinkage ratio in the height direction of 40 to 60% and a shrinkage ratio in the radial direction of the battery in the range of 2 to 15%.

By configuring the battery as described above,
It can reduce or eliminate the generation of residual stress in the part corresponding to the joint between the battery can and the ring-shaped spacer of the tack seal material, and prevent the external material from cracking or breaking due to external stress You can do it.

[0013]

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

FIG. 1 shows the appearance of a battery using a tack seal material B having the structure shown in FIG.
Shows the respective internal configurations.

As shown in FIGS. 1 and 2, A is a unit cell. The battery structure has a metallic battery can 1 made of a cylindrical SUS material or the like that also serves as one terminal and houses a power generating element (not shown). ,
A convex metallic terminal plate 2 also serving as the other terminal is hermetically sealed via an insulating packing 3 made of a polyolefin resin, and a ring-shaped synthetic resin having a thickness of 1 to 2 mm is provided on the bottom of the battery can 1. Inserting a spacer 4 made of metal, paper, etc., and using the above-mentioned tack seal material B as an exterior material,
And the upper and lower shoulders A1 and A2 and the outer side surface A3 of the unit cell are insulated and covered to constitute a battery.

FIG. 3 shows a sectional configuration of the tack seal material B. A paste material B1 mainly composed of an acrylic resin, a vapor-deposited aluminum film B2, and a heat-shrinkable resin film B3 having a thickness of 30 μm to 80 μm and made of polyethylene terephthalate (PET) resin are laminated. The film of Example 1 has a shrinkage ratio in the height direction of the battery of 40 to 60% and a shrinkage ratio in the radial direction of 2 to 15%. An ink layer B4 on which a design is printed and a varnish layer B5 made of a silicone resin film for protecting the ink layer B4 are further laminated on the film to form an overall thickness of 40 to 120 μm.

Next, as a specific example, a lithium manganese dioxide battery, CR123A (voltage 3 V, diameter 17 mm, height 3
4.5, electric capacity 1.3 Ah) under the following conditions:
The battery was randomly dropped 10 times from a height of 1.5 m onto concrete, and the crack / breakage occurrence rate at the joint between the tack seal material, the battery can, and the ring-shaped spacer was compared for 500 samples. The results are shown in (Table 1).

(Embodiment 1) The battery of Embodiment 1 is a heat-shrinkable resin film made of polyethylene terephthalate resin having a thickness of 30 μm, a shrinkage ratio of 60% in the height direction of the battery, and a shrinkage ratio of 2% in the radial direction. Using.

Example 2 The battery of Example 2 is a heat-shrinkable resin film made of a polyethylene terephthalate resin having a thickness of 50 μm, a shrinkage ratio of 50% in the height direction of the battery, and a shrinkage ratio of 10% in the radial direction. Using.

Example 3 The battery of Sample 3 was a heat-shrinkable resin film made of a polyethylene terephthalate resin having a thickness of 80 μm, a shrinkage ratio of 40% in the height direction of the battery and 15% in the radial direction. Was.

(Comparative Example) The battery of Comparative Example 1 uses a polyethylene terephthalate resin having a thickness of 30 μm as a heat-shrinkable resin film, a shrinkage ratio in the height direction of the battery of 60% and a shrinkage ratio in the radial direction of 20%. Was. The battery of Comparative Example 2
As the heat-shrinkable resin film, a polyethylene terephthalate resin having a thickness of 50 μm, a shrinkage ratio of 40% in the height direction of the battery, and a shrinkage ratio of 30% in the radial direction was used.

[0022]

[Table 1]

As is clear from Table 1, the battery of the present invention can prevent cracking and breakage occurring at a portion corresponding to the joint between the battery can of the tack seal material and the ring-shaped spacer.

As the heat-shrinkable resin film, a polyester resin such as polyethylene naphthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin having a thickness of 30 to 80 μm;
Similar results can be obtained by using a polyolefin resin such as a polypropylene resin.

The heat-shrinkable resin film has a thickness of 3
The reason why the thickness is set to 0 to 80 μ is that if it is 30 μ or less, it is not suitable for long-term use in terms of abrasion resistance and mechanical strength as an exterior material of this type of battery. If it is 80 μm or more, the variation in the heat shrinkage is large, the appearance after the heat shrinkage is not preferable, and the effective volume of the battery is small, which is disadvantageous.

On the other hand, the shrinkage rate in the radial direction is 2 to 15
The percentage of shrinkage in the height direction of the battery is 4% or less when it is 2% or less.
Since it is too small for 0 to 60%, tensile stress in the height direction remains. On the other hand, if it is 15% or more, since shrinkage is performed in two directions in the height direction and the radial direction, the deformation of this portion is distorted, and the appearance is dirty and the commercial value is reduced. The reason why the shrinkage ratio in the height direction is set to 40 to 60% is that when the shrinkage ratio is 40% or less, sufficient shrinkage cannot be obtained, and the adhesion of the tack seal material to the upper and lower shoulders of the battery does not become perfect. This is because it is difficult to provide a product with a large appearance and a uniform appearance.

[0027]

As is apparent from the above description, according to the present invention, the heat-shrinkable insulating resin material shrinks not only in the height direction of the battery but also in the radial direction, and the shrinkage rate By using a material that is within the specified range, the battery can be packaged without leaving tensile stress due to thermal shrinkage at the part of the tack seal material that abuts on the joint between the battery can and the ring-shaped spacer. Battery that can sufficiently withstand the impact and load of the battery.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of a battery according to one embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view of the battery.

FIG. 3 is a partially cutaway sectional view of the tack seal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery can 2 Metallic terminal board 3 Insulating packing 4 Spacer A unit cell A1 Upper shoulder A2 Lower shoulder A3 Outer side surface B Tack seal B1 Glue material B2 Aluminum vapor deposition film B3 Heat shrinkable film B4 Ink layer B5 Varnish layer

Claims (4)

[Claims] 1. A bottomed cylindrical battery can that also serves as one terminal housing a power generating element is hermetically sealed with a convex terminal plate also serving as the other terminal via an insulating packing, and a ring-shaped spacer is provided. A battery in which the battery can and the spacer are covered with a tack seal material made of a film-like heat-shrinkable resin, which is disposed at the bottom of the battery can, wherein the tack seal material has a thickness of 30 to 80 μm, and The battery has a shrinkage ratio in the height direction of 40 to 60% and a shrinkage ratio in the radial direction of 2-1.
A battery characterized by using a heat-shrinkable resin material of 5%. 2. The battery according to claim 1, wherein the heat-shrinkable resin material constituting the tack seal material is a polyester resin or a polyolefin resin. 3. The battery according to claim 2, wherein the polyester resin is a polyethylene terephthalate resin, a polyethylene naphthalate resin or a polybutylene terephthalate resin. 4. The battery according to claim 2, wherein the polyolefin resin is a polypropylene resin or a polyethylene resin.