JPH08185839A - Battery structure body - Google Patents

Abstract

PURPOSE: To provide a secondary battery structure body with high safety and high capacity by dividing a plastic cylindrical body into a plurality of housing pieces in the axial direction, then integrally bonding the housing pieces in fitting parts of undercut structure on divided surface. CONSTITUTION: A plastic cylindrical housing in which a unit cell is housed is formed with housing pieces 1, 2 divided in the axial direction, and fitting parts 1a, 2a and projections 1b, 2b having the female and male relation each other are formed in the housing pieces 1, 2, and the housing pieces 1, 2 are integrally bonded in corresponding fitting parts. The length of undercut in an insertion part I2 of the projection 2b (the fitting part 1a) is limited to 20-200% of the base thickness I1 , the width Ia of the fitting part 2a is limited to about 50% or more of the length of undercut in the insertion part I2 . The cylindrical housing is formed with plastic capable of injection molding and satisfying at least one of such properties that glass transition point is -100 to +200 deg.C, bending strain angle is 5-150 deg., and heat resistant temperature is 50-200 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery structure, and more particularly, to a high capacity secondary battery structure having excellent safety.

[0002]

2. Description of the Related Art A rechargeable battery such as a nickel-cadmium battery, a nickel-hydrogen battery, a lithium-ion battery, that is, a secondary battery is a computer, a mobile phone, or a camera-integrated type which is aimed at downsizing and weight reduction. VTR
It is often used as a power source for cordless consumer devices such as In addition, the use of secondary batteries is expanding as a power source for CD radio cassettes, powerful hand cleaners, etc. instead of conventional primary batteries.Currently, only nickel-cadmium batteries are used, but the amount of use is rapidly increasing. ing. From these circumstances, the secondary battery is desired to have a more suitable usage method than the case of the so-called primary battery, but on the other hand, in order to protect the safety of an unspecified number of users,
Even in the battery structure, attention is paid to the safety design and manufacturing of the battery in anticipation of all situations.

By the way, since the internal resistance (internal impedance) of each secondary battery is extremely small, it is possible to discharge a large current of, for example, several amperes in comparison with the volume of the primary battery, and the number of the secondary battery is small. It has the feature that it can be charged rapidly for about 1 to 10 minutes. Further, since the internal resistance of the battery is small, there is almost no drop in the terminal voltage in the initial stage of use, and the battery can be used as it is in various applications instead of the conventional primary battery. further,
Since the secondary battery can be reused by charging, it is not necessary to increase the capacity, and with the progress of battery manufacturing technology,
Batteries can be miniaturized.

Further, the secondary battery can be made smaller than the standard shape of a dry battery (primary battery) of a single type or a single type, and the miniaturized unit cell is inside an outer can (housing) having a standard shape. It is also used as a battery housed in a so-called dummy battery. In other words, it is used as a dummy battery and used as an alternative power source for the conventional primary battery without changing the battery mounting structure of the device used. Further, even in a battery pack containing a plurality of unit cells, it is indispensable to use an outer container (housing) for housing these. Here, in the outer container used for the construction of the dummy battery or the battery pack, the battery product is dropped from a certain height onto a wooden table, and the impact resistance test at that time has an influence on the battery performance, ignition, explosion, etc. The quality standards are based on safety considerations.

A battery structure of this type in which a unit cell is built in an outer container (housing) is disclosed in, for example, Japanese Patent Publication No.
60-53421, JP 61-19485, JP 61-362
No. 05 and No. 61-113370.
The disclosed configurations generally include built-in (interior)
The non-dividing cylindrical outer container is integrally formed in a concentric circle with respect to the unit cell, and a structure that cannot be easily opened is adopted. When the cylindrical outer container has a structure in which a plurality of divided cylindrical pieces are combined, it is desired that the cylindrical outer container has a structure that cannot be easily opened during the handling process.

Further, in the battery pack as well, the outer container is almost a tubular body made of plastic in order to meet the demands that the electric insulation is important and the workability is good. Then, structurally, a plurality of unit cells are built-in (interior) and wiring is provided in a plastic cylindrical body with openings at both ends, and then a plastic sealing body having a terminal portion is attached to the cylindrical body. It is attached to the openings at both ends. That is, a sealing body having terminal portions is superposed on the openings of both ends of the tubular body, and the superposed surfaces are ultrasonically welded so that they cannot be easily opened.

Furthermore, in order to make the outer dimensions of the battery pack compact, the outer case is formed into a box-shaped case, and the concavo-convex portions which are continuously fitted to each other are provided on the opposing opening end faces. A structure that is fitted and engaged to be integrated is also known (Japanese Patent Laid-Open No. 2-174052).

[0008]

However, in the case of the battery structure in which the unit cells are contained in the integrated cylindrical outer container (housing), the unit cells are non-interactively placed in the cylindrical outer container. There is a problem in that the process of press-fitting / interioring, and the process of disposing a safety element are complicated and mass productivity is significantly impaired. In this respect, when the cylindrical outer container is divided into a plurality of cylindrical shapes, the assembly workability can be improved to some extent, but the unit cells are press-fitted into the divided cylindrical shapes.
Since it is an interior method, there are still problems in terms of mass productivity.

Also, the cylindrical outer container is divided in the axial direction,
After incorporating the unit cell and, if necessary, a safety element, etc. in one divided piece, combine the other divided pieces with the one divided piece and join the divided surfaces with an adhesive, or on the peripheral surface of the combined divided pieces. It has also been attempted to attach a label and ensure the integrity with the attached label. However, when such a structure is adopted, since the divided pieces are not sufficiently integrated with each other, there is a risk that the divided pieces may separate and lose the function as the outer container due to, for example, damage to the adhesive label.

Further, even in the case of a battery pack, it is desired that the battery pack be made smaller and lighter year by year.
mm thickness is generally used. And, the reduction of the wall thickness of the plastic sealing body leads to a decrease in the reliability of ultrasonic welding, and the formation of continuous concave and convex engagement bumps on the opening end face portion complicates the processing technique. Incurs higher costs.

The present invention has been made in consideration of the above circumstances, and in a dummy battery or a battery pack, the normal handling does not cause the outer container (outer casing) to come off or be released, and the safety and reliability are sufficient. The purpose of the present invention is to provide a battery structure that secures the property.

[0012]

A battery structure according to the present invention comprises a plastic cylindrical casing (outer casing) having openings at both ends.
And a tubular unit cell or a group of unit cells that are respectively built in by exposing the positive electrode terminal side and the negative electrode terminal side separately in the opening of the tubular casing, the tubular structure comprising: -Shaped housing is composed of a plurality of housing pieces that are divided in the axial direction, and the plurality of housing pieces are joined and integrated with each other at a fitting part that has an undercut structure on the dividing surface. Is characterized by.

That is, according to the present invention, a plastic cylindrical housing containing (interior) a cylindrical unit cell or a plurality of unit cells (group of unit cells) is composed of a plurality of axially divided casing pieces. It is characterized in that the casing pieces are formed and are joined and integrated with each other by the fitting portion having the undercut structure provided on the opposing division surfaces. As the fitting portion having the undercut structure, for example, there is a snap fitting mechanism whose perspective view shows the configuration of the main part in FIG. That is, the plastic housing pieces 1 and 2
Corresponds to the fitting portion having a male-female relationship, for example, the fitting portion 1a and the projection portion 1b of the plastic housing piece 1, to which the projection portion 2b and the fitting portion 2a of the plastic housing piece 2 correspond, respectively. It is configured to be joined and integrated by the mating fitting part. Here, the dimensional relationship of the protrusions 2b of the plastic housing piece 2 (the same applies to the fitting portion 1a of the corresponding plastic housing piece 1 below) is as follows.
The length l ₂ of the undercut of the insertion part is 20 of the base thickness l ₁ .
~ 200%, more preferably 50-150%. Further, the fitting portion 2a width l ₃ of the plastic housing piece 2, the insertion portion undercut 50% of the length l ₂ or more, and more preferably set to at least 80%, the slide core in the injection mold Molding is possible without using it, which is economical and preferable.

FIG. 2 is a perspective view showing another snap fitting mechanism, and similarly, plastic housing pieces 1'and 2 '.
This is an example of joining and integrating them by snap connection. Here, in order to facilitate the push-fitting of the fitting portion 1a 'of the plastic housing piece 1', a part of the fitting portion 1a 'is fitted to the protrusion 2b' of the plastic housing piece 2 '. The notch 1c 'is provided so that it is easily deformed when stressed. The dimensional relationship in comparison with the case shown in FIG. 1 is that l ₂ in FIG. 1 corresponds to the sum of l ₂ ′ + l ₂ ″.

The snap-type fitting mechanism shown in FIGS. 1 and 2 has such an integrity that once fitted / integrated, it cannot be easily released / disengaged manually. Then, such a structure is based on the basic mechanism shown in FIG. 1 and is, for example, as shown in plan view in FIGS. 3 (a) to 3 (d).
It can lead to various variations. That is, forming a side surface on the fitting portion 1a of the plastic housing piece 1 shown in FIG. 1 or one of the upper and lower surfaces thereof so that the protrusions 2b of the plastic housing piece 2 do not shift, or It may be provided on a thickened portion. The location and number of the fitting parts depend on the size and weight of the dummy battery and the battery pack, the wall thickness of the plastic case piece, etc., but are generally provided at intervals of 2 to 5 cm. Is desirable.

As described above, in the battery structure according to the present invention, the casing piece 1, which constitutes the plastic cylindrical casing 1,
The fitting portions of the divided surfaces 1 ', 2, 2'which face each other have an undercut structure. Therefore, for example, when fitting the fitting portions 1a, 1a 'and the protruding portions 1b, 1b',
It is premised that a part of the insertion openings of the fitting portions 1a and 1a 'are distorted and deformed by the force at the time of inserting the protrusions 1b and 1b'.
After the protrusions 1b and 1b 'are set in the fitting portions 1a and 1a', the strain deformation returns to the original shape, and the protrusions 1b and 1b
1b 'must be in a form that does not easily come off.
Such strain deformation phenomenon is called plastic deformation and is a physical property characteristic of a plastic material, and in the practice of the present invention, it is desirable to consider physical properties such as glass transition point, bending strain angle and heat resistant temperature.

Here, the glass transition point indicates the rigidity of the material, and is generally about -100 to + 200 ° C, preferably -100 ° C.
It is about 50 to + 180 ° C. That is, if the rigidity is low, permanent set is likely to occur, and conversely, if the rigidity is high, fitting becomes difficult. Bending strain shows the ease of fitting, and it depends on the undercut structure of the fitting part.
It is about 0 °, preferably about 10 to 90 °. Further, the heat resistance temperature is about 50 to 200 ° C, preferably 70 to 70 ° C when it is indicated by the three-point support heat distortion temperature (HDT) under a load of 18.56 kg / cm ^2.
~ 150 ℃ is recommended.

As described above, in consideration of practically desired physical properties, the material for the cylindrical casing is, for example, polystyrene resin such as GP polystyrene, HI polystyrene, ABS resin, or the like, such as polypropylene or high molecular weight polyethylene. Polyolefin resin such as 6 nylon,
Polyamide resins such as 66 nylon, 610 nylon, 46 nylon and wholly aromatic nylon, for example, polyester resins such as polycarbonate, polyethylene terephthalate and polybutylene terephthalate, polyarylate resins, modified polyphenylene ether resins, polyvinyl chloride resins, polyacetals. Resin, thermoplastic polyurethane resin, ACS resin, polyvinyl alcohol resin, ionomer and the like can be mentioned. And, to these resins, within a range that does not impair the physical properties described above, for example, inorganic fillers such as glass fiber, talc, calcium carbonate, potassium titanate, organic fibers and powders, flame retardants, antistatic agents, lubricants. It may be a mixture of the above.

Further, in the battery structure according to the present invention, a safety element such as a thermostat, a PTC, and a thermal fuse connected in series with the unit cell is provided in a plastic casing having a fitting mechanism having an undercut. It is also possible to incorporate. That is, in order to incorporate the safety element in the integrally molded cylindrical plastic housing (particularly in the dummy battery), the workability of the mounting process (assembly) is extremely poor, but for example, the plastic housing is divided into two parts. In the case of the configuration of combining the pieces, the work of incorporating and assembling the unit cell and the safety element becomes easier. And
When incorporating and arranging the safety element, the safety element may be stored in an arbitrary space in the plastic housing while maintaining electrical safety. However, according to the experiments by the present inventors, when the battery is brought into contact with the side surface of the battery or installed at a very close distance to the battery, the behavior of the battery and the safety control by the safety element are effective. It was confirmed that

[0020]

According to the present invention, a plastic cylindrical casing containing a cylindrical unit cell or a group of unit cells is formed of a plurality of axially divided casing pieces, and these casing pieces are formed. Is joined and integrated with each other by a fitting portion of a snap mechanism having an undercut structure provided on the opposing division surfaces. That is, by making good use of the plasticity and mechanical pressure deformability of the plastic forming the tubular casing, the plurality of casing pieces divided in the axial direction (along the axis) are They are fitted and integrated so that they cannot be easily separated from each other on the opposing split surfaces. The structure of fitting / integrating the housing pieces maintains the required bonding / integrality in normal handling operations, so even in practical use as a dummy battery or a pack battery, mechanical strength and standard dimensions / It can be said that the shape is maintained and the protective function is maintained and ensured, which greatly contributes to the improvement of safety and reliability.

[0021]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 4A and 4B.

FIG. 4 (a) is a vertical cross-sectional view showing a schematic configuration example of a rechargeable dummy battery, and FIG. 4 (b) is a horizontal cross-sectional view taken along the line AA of FIG. 4 (a). 4 (a) and (b),
Reference numerals 1 and 1 ′ are two-piece integrated plastic casing pieces (exterior casing pieces) of a designated battery shape, such as a single type or a single type. Then, a fitting portion having an undercut provided with a fitting portion 1a and a projection portion 1b is provided at a predetermined position / position on the mating surface (opposing surface) of one plastic housing piece 1, and the other plastic housing. Two mating faces (opposing faces)
At the predetermined locations and positions of the
Fittings with undercuts with b'are provided correspondingly. Here, as shown in FIG. 1, the structure of the fitting portion having the undercut is such that the fitting portion 1a region is formed on the plastic casing piece 1 side.
I ₁ = I ₂ and set to 1: 1, while on the plastic housing piece 2 side, the projection 2b area is I ₁ = I ₂ and 1:
It is set to correspond to 1 mutually. In addition, in this configuration example, the fitting portion having the undercut has an upper end side, a central portion,
It is installed at three locations on the upper end side.

Further, 3 is the plastic casing piece 1
And a unit cell (for example, a nickel-hydrogen battery) mounted and arranged in the plastic housing assembled from the plastic housing piece 2, and 4 as a safety element also mounted and arranged in the plastic housing. It is a thermostat. The thermostat 4 is located on the side surface of the unit cell 3, and is connected to the cathode side of the unit cell 3 and the bottom metal 5.
It is connected in series between and. Further, 6 is a top metal whose exposed surface is covered with an insulating layer 6a except for the front end surface side, which is electrically connected to the anode side of the unit cell 3. That is, in the configuration of this dummy battery, the plastic housing is of a double-ended type, and both the cathode side and the positive electrode side of the unit cell 3 that is internally mounted are mounted so as to seal the both-end openings of the plastic housing. Each of the phantom metal 5 and the top metal 6 thus formed has a configuration in which it is led out (exposed).

Next, an example of an assembling process of the dummy battery having the above structure will be described.

First, a required unit cell 3 such as a nickel-hydrogen secondary battery, a plastic casing piece provided with a fitting portion of the snap mechanism having the above-described undercut,
For example, the ABS resin case pieces 1 and 2, the thermostat 4, the bolt metal 5, the top metal 6 and the like are prepared.
Here, the ABS resin has a bending strain angle of 15 to 30 ° and a heat resistant temperature of 80 to 100 ° C. at 18.6 kgf / cm ² . Next, the unit cell 3 is attached to either one of the plastic housing pieces 1 or 2 and the thermostat 4 having the connecting lead at a predetermined position of the other plastic housing piece 2 or 1.
Is installed. After that, the bolt metal 5 and the top metal 6 are mounted on the mounting portions 5a and 6a of the plastic housing piece 1 or 2 on which the unit cell 3 is mounted, for example. In this state, the divided surfaces of the plastic casing pieces 1 and 2 that face each other are opposed and aligned, and the fitting portions of the corresponding snap mechanisms are fitted to join and integrate them. That is, an external force is applied to the corresponding snap mechanism areas of the plastic housing pieces 1 and 2 to utilize the plastic deformability of the plastics forming the housing pieces 1 and 2, and thus the corresponding sandwiching portions are sandwiched. The dummy batteries are assembled and formed by fitting the parts 1a and 2a and the projections 1b and 2b into one piece and joining and integrating them.

In the dummy battery thus constructed, the plastic casing in which the unit cells 3 and the like are built in and mounted is
By joining and integrating the plastic housing pieces 1 and 2 that form this plastic housing, which do not easily come off,
It provides the necessary and sufficient bonding and integrity during normal handling, such as during packaging of dummy batteries, during transportation, and when attaching / detaching to / from equipment as a power source. In other words, when this dummy battery is dropped from a predetermined height onto a wooden table surface and the impact resistance is evaluated, the housing pieces do not separate from each other (separation of the outer housing), and the battery performance is not affected. No adverse effect was observed. Although the dummy battery structure has been described above as an example, similar results were also found in the configuration of a battery pack in which a plurality of unit cells are contained and mounted in a plastic casing. That is, in order to incorporate and mount a plurality of unit cells 3, except that the internal structure and size are set correspondingly, a two-division type plastic casing piece is used and the opposing division surface is predetermined. A snap mechanism having an undercut was installed at a location, and a plastic battery case for a battery bag that is joined and integrated by fitting of the snap mechanism was used to construct a battery pack according to the above means. Then, when the battery pack was dropped from a predetermined height onto a wooden surface and evaluated for impact resistance, it was confirmed that the housing pieces did not separate from each other (separation of the outer housing), and the battery performance showed no difference. No adverse effect was observed.

The present invention is not limited to the above-mentioned construction, and various modifications can be made without departing from the spirit of the invention.

[0028]

As can be seen from the above description, according to the battery structure of the present invention, the plastic forming of the cylindrical casing is prevented from being plastically deformed and the mechanical pressure deformability is skillfully utilized. The plurality of housing pieces that are divided in the axial direction (along the axis) are fitted and integrated so that they cannot be easily separated from each other on the opposing division surfaces. In addition, the fitting / integrating structure of this housing piece ensures the required joining / integrality during normal handling operations, so it has a mechanical strength even when used as a dummy battery or a battery pack. In addition, it can be said that it functions as a battery structure with high safety and reliability by maintaining and maintaining the standard dimensions and shape and maintaining and maintaining a protective function.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of a main part of a snap fitting mechanism having an undercut included in a casing piece forming a plastic cylindrical casing of a battery structure according to the present invention.

FIG. 2 is a perspective view showing another configuration example of a main part of a snap fitting mechanism having an undercut included in a casing piece forming a plastic cylindrical casing of a battery structure according to the present invention.

FIG. 3 is a plan view showing another configuration example of a main part of a snap fitting mechanism having an undercut included in a casing piece forming a plastic cylindrical casing of a battery structure according to the present invention.

4A and 4B show an example of a main configuration of a battery structure according to the present invention, in which FIG. 4A is a vertical sectional view and FIG. 4B is a horizontal sectional view.

[Explanation of symbols]

1,1 ', 2,2' ... Plastic housing pieces
1a, 1a ', 2a, 2a' ... Fitting parts 1b, 1b ',
2b, 2b '... Protrusion 3c' ... Notch
3 ………… Unit cell 4 ………… Thermostat
5 ... Bottom metal 6 ... Top metal

Claims (4)

[Claims] 1. A plastic cylindrical housing having openings at both ends,
A battery structure comprising: a cylindrical battery having a positive electrode terminal side and a negative electrode terminal side exposed separately in an opening of the cylindrical casing, wherein the cylindrical casing is arranged in an axial direction. A battery structure comprising a plurality of divided casing pieces, and the plurality of casing pieces are joined and integrated with each other at a fitting portion having an undercut structure on the dividing surface. . 2. The undercut structure is such that one surface of the fitting depth is undercut, and the length ratio to the other surface forming the pair is
The battery structure according to claim 1, wherein the battery structure is 20 to 200%. 3. The plastic cylindrical casing is injection-molded to satisfy at least one of a glass transition point of −100 to + 200 ° C., a bending strain angle of 5 to 150 °, and a heat resistant temperature of 50 to 200 ° C. The battery structure according to claim 1 or 2, wherein the battery structure is formed of a possible plastic. 4. The battery structure according to claim 1, wherein a safety element component connected in series to the unit cell is built in a plastic cylindrical casing. .