JP5638748B2 - Flat battery - Google Patents

Description

  The present invention relates to a flat battery called a coin battery or a button battery.

  A flat battery called a coin battery or a button battery is used as a power source mainly for memory backup of information equipment and video equipment. FIG. 11 shows a perspective view of an example of a conventional flat battery. The flat battery 100 is a combination of an outer can 101 that is a positive electrode can and a sealing can 102 that is a negative electrode can.

  12 is a cross-sectional view taken along line BB in FIG. In the flat battery 100, a power generation element 110 is accommodated and filled with a non-aqueous electrolyte. A gasket 103 is interposed between the peripheral wall 104 of the outer can 101 and the folded portion 107 of the peripheral wall 105 of the sealing can 102. By forming the folded portion 107 in the sealing can 102, the strength of the close contact portion with the gasket 103 is ensured.

  The front end 104 a of the peripheral wall 104 of the outer can 101 is curved toward the central axis 106 side of the sealing can 102, and the outer can 101 is caulked and fixed to the sealing can 102. Thus, the gap between the outer can 101 and the sealed can 102 is sealed by the gasket 103, and the outer can 101 and the sealed can 102 having different polarities are insulated.

  For example, the following patent documents 1 and 2 are also described as the flat battery having a configuration corresponding to the folded portion 107. The configuration in which the folded portion 107 is formed is advantageous in terms of strength but disadvantageous in terms of increasing the capacity.

  Specifically, the outer dimension of the flat battery 100 is defined as a predetermined dimension. In the flat battery having the same outer dimensions, the configuration with the folded portion 107 moves the corner portion 108 of the sealing can 102 toward the central shaft 106 as compared with the configuration without the folded portion 107, and the capacity is accordingly increased. Becomes smaller.

On the other hand, the following Patent Documents 3-6 describe a configuration without the folded portion 107, and each of these configurations is advantageous in terms of increasing the capacity.
WO02 / 013290 Publication JP 2003-151511 A JP-A-7-57706 JP 2003-68254 A JP-A-4-341756 Japanese Patent No. 3399801

  However, the configuration without the folded portion 107 as proposed in Patent Documents 3-6 is advantageous in terms of increasing the capacity, but is disadvantageous in terms of strength. Specifically, in FIG. 12, when the tip 104a of the peripheral wall 104 of the outer can 101 is curved toward the central axis 106 and caulked, the peripheral wall 105 of the sealing can 102 is also deformed toward the central axis 106. . That is, the peripheral wall 105 is deformed in a direction away from the inner peripheral surface of the gasket 103. At this time, in the configuration without the folded-back portion 107, the adhesion between the peripheral wall 105 and the gasket 103 becomes weak, and sealing with the gasket 103 may be insufficient.

  In Patent Document 3, a configuration for preventing such insufficient sealing is proposed, but there is no proposal to make up for insufficient strength, and processing for changing the thickness of the peripheral wall is also necessary. .

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a flat battery that is advantageous for increasing the capacity while ensuring sealing performance.

In order to achieve the above object, a flat battery of the present invention is a flat battery in which an opening of an outer can is sealed with a sealing can, and the outer can and the sealing can have a peripheral wall standing on the outer periphery of the bottom. A cylindrical opening at one end, and a gasket is interposed between the outer peripheral surface of the peripheral wall of the sealing can and the inner peripheral surface of the peripheral wall of the outer can, and the tip of the peripheral wall of the outer can The outer can is caulked and fixed to the sealing can by curving toward the central axis side of the sealing can, and in the cross-sectional shape in the central axis direction of the sealing can, the peripheral wall of the sealing can is a single unfolded A bottom portion of the sealing can is a flat portion, a peripheral wall of the sealing can is a straight portion connected to the flat portion via a corner portion, and a shoulder portion that forms a step with respect to the straight portion. and in this order from the side of the bottom portion, and the flat portion and the straight portion Nasu angle θ1 is equal to or less than 95 degrees greater than 90 degrees.

  According to the present invention, it is advantageous to increase the capacity while ensuring sealing performance.

  According to the flat battery of the present invention, the angle θ1 formed by the flat portion and the straight portion of the sealing can is larger than 90 degrees, so that the adhesion at the contact portion between the peripheral wall of the sealing can and the gasket is maintained, and Sealability is maintained. Moreover, the improvement effect of the sealing property by the spring back of the surrounding wall of a sealing can and the effect which intensity | strength increases by the work hardening of the corner part vicinity of a sealing can are acquired.

  In the sealed battery of the present invention, the angle θ1 is preferably 90.5 degrees or more. According to this configuration, the angle θ1 can be surely made larger than 90 degrees.

Further, the angle θ1 is, Ru der below 95 degrees. According to this configuration, the dead volume of the internal volume can be reduced.

  The gasket is preferably pressed against the peripheral wall of the sealing can so as to press the peripheral wall of the sealing can toward the central axis. According to this configuration, the insulation and sealing properties between the outer can and the sealed can with different polarities are improved.

  Further, the peripheral wall of the sealing can forms a step through a shoulder portion, the gasket is interposed between the shoulder portion and the peripheral wall of the exterior can, and in the height direction of the sealing can It is preferable that the gasket is pressed. Also with this configuration, the insulation and sealing properties between the outer can and the sealed can with different polarities are improved.

  Moreover, in the single-piece | unit state before the assembly of the said sealing can, it is preferable that angle (theta) 2 which the said plane part and the said linear part make is 92 degree | times or more. According to this configuration, the angle θ1, which is the angle in the completed state of the sealed battery, can be more surely made larger than 90 degrees.

  Further, in the single unit state before assembling the sealing can, if the angle formed by the flat portion and the straight portion is an angle θ2, the angle difference θ3 between the angle θ2 and the angle θ1 is 0.5 ° or more and 5 It is preferable that the angle is not more than °. According to this configuration, while facilitating manufacture, an effect of improving the sealing performance by springback of the peripheral wall of the sealed can and an effect of increasing the strength by work hardening in the vicinity of the corner portion of the sealed can are obtained.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a perspective view of a flat battery according to an embodiment of the present invention. The flat battery 1 is a combination of an outer can 2 that is a positive electrode can and a sealing can 3 that is a negative electrode can. An example of the flat battery 1 is one having an outer diameter (D dimension in FIG. 2) of 20.0 mm and a thickness of 5 mm.

  2 is a cross-sectional view taken along line AA in FIG. The outer can 2 has a cylindrical shape in which a peripheral wall 12 is erected on the outer periphery of the bottom 11 and one end is opened. The sealing can 3 has a cylindrical shape in which a peripheral wall 16 is erected on the outer periphery of the flat portion 15 as a bottom portion, and one end is opened. A gasket 4 is interposed between the inner peripheral surface of the peripheral wall 12 of the outer can 2 and the outer peripheral surface of the peripheral wall 16 of the sealing can 3.

  The distal end portion 12 a of the peripheral wall 12 of the outer can 2 is curved toward the central axis 9 side of the sealing can 3, and the outer can 2 is caulked and fixed to the sealing can 3. Thus, the gap between the outer can 2 and the sealed can 3 is sealed by the gasket 4 and the outer can 2 and the sealed can 3 having different polarities are insulated.

  In the flat battery 1, a power generation element 10 is accommodated and filled with a nonaqueous electrolytic solution. The power generation element 10 includes a positive electrode material (electrode material) 5 in which a positive electrode active material or the like is hardened in a disk shape, a negative electrode material (electrode material) 6 in which a metal lithium or a lithium alloy as a negative electrode active material is formed in a disk shape, and a non-woven fabric The separator 7 is included. A positive electrode material 5 and a negative electrode material 6 are arranged via a separator 7. A positive electrode ring 8 made of stainless steel or the like is mounted on the outer surface of the positive electrode material 5.

  FIG. 3 shows an exploded view of the flat battery 1 shown in FIG. As described above, the outer can 2 and the sealing can 3 have a cylindrical shape with one end opened. These can be formed, for example, by press-molding a stainless material. The peripheral wall portion 16 of the sealing can 3 includes a straight portion 17, and a corner portion 18 is formed at the intersection of the flat portion 15 and the straight portion 17. Further, the peripheral wall portion 16 forms a step through the shoulder portion 19.

  The gasket 4 is a resin molded product, and is molded by a resin composition containing, for example, polyphenylene sulfide (PPS) as a main component and an olefin elastomer. The gasket 4 is a ring-shaped member, and an inner wall 21 and an outer wall 22 rise from the base portion 20. A gap 23 is formed between the inner wall 21 and the outer wall 22. The peripheral wall 16 of the sealing can 3 can be inserted into the gap 23.

  The positive electrode material 5 is formed by integrally forming a positive electrode active material in a disc shape with the positive electrode ring 8. Examples of the positive electrode active material include a material obtained by molding a positive electrode mixture prepared by mixing manganese dioxide with graphite, a tetrafluoroethylene-hexafluoropropylene copolymer, and hydroxypropylcellulose.

  The separator 7 is formed of a nonwoven fabric, for example, a nonwoven fabric made of polybutylene terephthalate fibers.

The separator 7 is impregnated with a non-aqueous electrolyte. As the non-aqueous electrolyte, for example, a solution in which LiClO ₄ is dissolved in a solvent in which propylene carbonite and 1,2-dimethoxyethane are mixed can be used. The thickness of the separator 7 is, for example, about 0.3 to 0.4 mm.

  FIG. 4 shows an enlarged view of the vicinity of the peripheral wall 16 of the sealing can 3 shown in FIG. The angle θ <b> 2 is an angle formed by the flat portion 15 and the straight portion 17 in the single state of the sealing can 3. The angle θ2 is greater than 90 degrees. As a result, the inner diameter of the sealing can 3 increases from the corner portion 18 toward the tip 16 a of the peripheral wall portion 16.

  When assembling the components shown in FIG. 3, the assembly is performed with the top and bottom of FIG. 3 turned upside down. FIG. 5 shows a cross-sectional view in the middle of assembly. FIG. 5A is a cross-sectional view showing a state where the gasket 4 is attached to the sealing can 3. The gasket 4 is attached to the sealing can 3 by inserting the peripheral wall 16 of the sealing can 3 into the gap 23 of the gasket 4.

  FIG. 5B shows a state where the power generation element 10 is stored in the sealed can 3. The negative electrode material 6 is fixed to the sealing can 3 with a conductive adhesive or the like. The separator 7 and the positive electrode material 5 are stacked on the negative electrode material 6. Thereafter, a nonaqueous electrolytic solution is injected into the sealing can 3.

  FIG. 6 is a cross-sectional view showing a state in which the outer can 2 is fitted to the assembly of FIG. In this state, the outer peripheral surface of the gasket 4 and the inner peripheral surface of the peripheral wall 12 of the outer can 2 are fitted. The process proceeds from the state shown in FIG. 6 to the caulking process. In the caulking process, the distal end portion 12 a of the peripheral wall 12 of the outer can 2 is bent toward the central axis 9 side of the sealing can 3.

  FIG. 7 is a cross-sectional view showing a state before caulking. The flat battery 1 shown in FIG. 6 is sandwiched between the knockout pin 30 and the punch 31. The mold surface of the sealing mold 32 is fitted to the outer peripheral surface of the peripheral wall 12 so as to surround the peripheral wall 12 of the outer can 2. In this state, the knockout pin 30 and the punch 31 are lowered. Thus, the peripheral wall 12 of the outer can 2 is bent along the curved surface of the sealing mold 32 toward the central axis 9 of the sealing can 3.

  FIG. 8 is a cross-sectional view showing a state in which the knockout pin 30 and the punch 31 have been lowered. In this state, the gasket 4 is sandwiched between the inner peripheral surface of the peripheral wall 12 of the outer can 2 and the outer peripheral surface of the peripheral wall 16 of the sealing can 3.

  Furthermore, the tip of the gasket 4 is pressed against the peripheral wall 16 of the sealing can 3 so as to press the peripheral wall 16 toward the central axis 9. This improves the insulation and sealing properties between the outer can 2 and the sealed can 3 having different polarities.

  Further, the gasket 4 is pressed in the height direction of the sealing can 3 between the shoulder 19 of the sealing can 3 and the tip 12 a of the peripheral wall 12 of the outer can 2. This also improves the insulation and sealing between the outer can 2 and the sealed can 3.

  The flat battery 1 is taken out from the state of FIG. 2 is an illustration in which the flat battery 1 is taken out from the state of FIG. 8 and turned upside down. In this state, the peripheral wall 16 of the sealing can 3 is also deformed as the peripheral wall 12 of the outer can 2 is caulked.

  As shown in FIG. 4, in the sealed can 3 before being assembled, the angle formed by the flat portion 15 and the straight portion 17 is θ2, and the angle θ2 is greater than 90 degrees. In the state after caulking in FIG. 2, the angle θ2 is an angle θ1 smaller than the angle θ2. This will be described with reference to FIG.

  FIG. 9 is a cross-sectional view for explaining a change in angle between the flat portion 15 and the straight portion 17 in the single state and the assembled state of the sealing can 3. The angle θ2 in FIG. 9 is the same as the angle θ2 in FIG. 4, and is an angle formed by the flat portion 15 and the straight portion 17 in a single state before the sealing can 3 is assembled.

  A two-dot chain line in FIG. 9 shows the peripheral wall 16 after caulking and fixing, and the peripheral wall 16 is deformed to the central axis 9 side. As a result, the angle formed by the flat surface portion 15 and the straight line portion 17 changes from the angle θ2 to an angle θ1 smaller than the angle θ2.

  The angle θ1 after the caulking is fixed is maintained larger than 90 degrees. Accordingly, in FIG. 2, the contact portion between the peripheral wall 16 of the sealing can 3 and the gasket 4 is kept in close contact, and the sealing performance by the gasket 4 is kept.

  In addition, after the caulking process, a spring back effect is obtained in which the peripheral wall 16 of the sealing can 3 attempts to return to the original state. As a result, the peripheral wall 16 presses the gasket 4. This also helps to secure the sealing performance by the gasket 4.

  On the other hand, in order to maintain the state where the peripheral wall 16 presses the gasket 4, the strength in the vicinity of the corner portion 18 where stress is concentrated is required. In the vicinity of the corner portion 18, work hardening is obtained by bending from the angle θ2 to the angle θ1. As a result, the strength in the vicinity of the corner portion 18 can be increased.

  Next, the numerical range of the angles θ1 and θ2 will be described. The angle θ1 after caulking and fixing is a value larger than 90 degrees as described above, and satisfies the following formula (1). In order to ensure that the angle θ1 is greater than 90 degrees, it is preferable to satisfy the expression (2).

Formula (1) 90 ° <θ1
Formula (2) 90.5 ° ≦ θ1
In consideration of securing the internal volume, the angle θ1 is preferably in the range of the following formula (3), and more preferably in the range of the formula (4).

Formula (3) 90 ° <θ1 ≦ 95 °
Formula (4) 90.5 ° ≦ θ1 ≦ 93 °
The reason why the upper limit value is set to 95 ° in Equation (3) is that the dead volume of the internal volume increases as the angle θ1 increases. Specifically, in FIG. 2, the external dimension D of the flat battery 1 needs to be maintained. If the angle θ1 is increased while the outer dimension D is fixed, the corner portion 18 is displaced toward the central axis 9 and the internal volume is reduced.

  Further, the angle difference θ3 (θ2−θ1) between the angle θ2 in the single state of the sealing can 3 and the angle θ1 after caulking is preferably in the range of the following formula (5), and the range of the formula (6) is more preferable. preferable.

Formula (5) 0.5 ° ≦ θ3 ≦ 5 °
Formula (6) 1 ° ≦ θ3 ≦ 3 °
If the angle difference θ3 is too large, it becomes difficult to insert the gasket 4 shown in FIG. 5A and to fit the outer can 2 shown in FIG. If the angle difference θ3 is within the range of the formulas (5) and (6), it is possible to obtain the effect of improving the sealing performance by the spring back and the effect of increasing the strength by work hardening in the vicinity of the corner portion 18 while facilitating the production. .

  In the vicinity of the lower limit values of the expressions (5) and (6), the degree of the springback effect and work hardening is small, but if the angle θ1 after caulking and fixing is maintained larger than 90 degrees, the gasket The sealing performance by 4 is not changed.

  Next, in order to make the angle θ1 larger than 90 degrees as described above, it is preferable that the angle θ2 in the single state of the sealing can 3 satisfies the following formula (7).

Formula (7) 92 ° ≦ θ2
On the other hand, considering the above formulas (3) and (4) for securing the internal volume, and the above formulas (5) and (6) for balancing the ease of manufacture with work hardening and the springback effect The angle θ2 is preferably in the range of the following formula (8), and more preferably in the range of formula (9).

Formula (8) 92 ° ≦ θ2 ≦ 98 °
Formula (9) 93 ° ≦ θ2 ≦ 95 °
As an embodiment within the above numerical range, the angle θ1 of the sealing can 3 after caulking and fixing is 90.9 °, the angle θ2 in the single state of the sealing can 3 is 93.8 °, and the angle difference θ3 is 2 .9 ° may be mentioned.

  Next, the present embodiment will be compared with a comparative example with reference to FIG. Fig.10 (a) is principal part sectional drawing of the flat battery 100 which concerns on a comparative example. This figure has the same configuration as the conventional example shown in FIG. FIG.10 (b) is principal part sectional drawing of the flat battery 1 which concerns on this Embodiment. This figure has the same configuration as the flat battery 1 shown in FIG.

  Both the flat battery 100 and the flat battery 1 have the same outer dimension D. Whereas the flat battery 100 forms the folded portion 107 in the sealing can 102, the peripheral wall 16 of the flat battery 1 is a single wall that is not folded.

  Even if the folded-back portion 107 is omitted from the sealing can 102, the hanging margin between the shoulder portion 109 of the peripheral wall 105 and the gasket 103 does not change. In this case, the entire peripheral wall 105 of the sealing can 102 can be moved to the peripheral wall 104 side of the outer can 101 by the amount that the folded portion 107 is omitted.

  The state after the movement corresponds to FIG. In the flat battery 1 of FIG. 10B, the inner peripheral surface of the sealing can 3 is moved outward by the dimension A, compared to the flat battery 100 of FIG. As a result, the flat battery 1 can have a larger capacity while having the same external dimension D as the flat battery 100.

  Also, the formation of the straight portion 17 is advantageous for securing the capacity. In FIG. 10B, when the radius of the corner portion 18 is increased, the straight portion 17 becomes a part of the corner portion 18. In this configuration, the corner portion 18 is displaced toward the central axis 9, which is disadvantageous for securing the capacity. That is, the capacity can be increased as the radius of the corner portion 18 is reduced and the length of the straight portion 17 is increased.

  On the other hand, as described above, since the flat battery 1 has the angle θ1 larger than 90 degrees, the sealing performance by the gasket 4 can be secured. Further, the sealing performance can be further improved by the springback effect, and the lack of strength can be compensated by work hardening.

  That is, the present embodiment can be said to be a configuration that is advantageous for securing the sealing performance by the gasket 4 while the peripheral wall 16 of the sealing can 3 is a single wall that is not folded back and has a structure that is advantageous for high capacity. .

  In addition, the sealing can 3 according to the present embodiment forms a straight portion 17 in the cross-sectional shape of the peripheral wall 16 both before and after the caulking process. On the other hand, external force is applied to the peripheral wall 16 by caulking. For this reason, after caulking, the straight portion 17 may not be able to maintain a complete straight shape. Even if it is such a structure, it does not change that the effect which improves the sealing performance by the gasket 4 is acquired.

  Therefore, the shape of the straight line portion 17 includes not only a complete straight line but also a curve that has a large radius of curvature and can be regarded as a straight line. More specifically, the shape of the straight portion 17 includes a curve having a radius of curvature of 5 mm or more, or a curve having a radius of curvature of 20 times or more the radius of the corner portion 18.

  Moreover, although the dimension of the flat battery 1 and the material of the component were demonstrated using FIGS. 1-3, these are an example, The thing of another dimension may be used, Even if it uses what was other materials Good.

  As described above, according to the present invention, the flat battery of the present invention is mainly used for memory backup such as information equipment and video equipment, because it is advantageous for high capacity while ensuring sealing performance. It is useful as a power source.

The perspective view of the flat battery which concerns on one embodiment of this invention. Sectional drawing in the AA line of FIG. FIG. 3 is an exploded view of the flat battery 1 shown in FIG. 2. The enlarged view of the surrounding wall 16 vicinity of the sealing can 3 shown in FIG. It is sectional drawing in the middle of the assembly of the flat battery which concerns on one embodiment of this invention, (a) A figure is sectional drawing which shows the state which attached the gasket 4 to the sealing can 3, (b) A figure is a sealing can FIG. 3 is a cross-sectional view showing a state where a power generation element 10 is housed in 3. Sectional drawing which shows the state which made the exterior can 2 fit to the assembly of FIG.5 (b). Sectional drawing which shows the state before crimping which concerns on one embodiment of this invention. Sectional drawing which shows the state after caulking which concerns on one embodiment of this invention. The figure explaining the change of the angle which the plane part and a linear part make in the single-piece | unit state and assembly completion state of the sealing can which concern on one embodiment of this invention. It is sectional drawing for comparing this Embodiment and a comparative example, (a) A figure is sectional drawing of a comparative example, (b) A figure is sectional drawing of this Embodiment. The perspective view of an example of the conventional flat battery. Sectional drawing in the BB line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat battery 2 Exterior can 3 Sealing can 4 Gasket 11 Bottom part of exterior can 12 Perimeter wall of exterior can 15 Plane part of sealed can 16 Perimeter wall of sealed can 17 Straight part of sealed can 18 Corner part of sealed can 19 Shoulder of sealed can Part

Claims (6)

A flat battery in which the opening of the outer can is sealed with a sealing can,
The outer can and the sealing can have a cylindrical shape in which a peripheral wall is erected on the outer periphery of the bottom, and one end is opened,
A gasket is interposed between the outer peripheral surface of the peripheral wall of the sealing can and the inner peripheral surface of the peripheral wall of the outer can,
The outer wall of the outer peripheral can be curved to the center axis side of the sealed can, and the outer can is caulked and fixed to the sealed can;
In the cross-sectional shape in the central axis direction of the sealing can,
The peripheral wall of the sealing can is a single wall without folding,
The bottom part of the sealing can is a flat part,
The peripheral wall of the sealing can includes a straight part connected to the flat part via a corner part, and a shoulder part forming a step with respect to the straight part in this order from the bottom part side ,
The flat battery according to claim 1, wherein an angle θ1 formed by the flat portion and the straight portion is greater than 90 degrees and less than or equal to 95 degrees.   The flat battery according to claim 1, wherein the angle θ1 is 90.5 degrees or more.   The flat battery according to claim 1, wherein the gasket is pressed against the peripheral wall of the sealing can so as to press the peripheral wall of the sealing can toward the central axis. Flat form according to the gasket and is interposed, one of claims 1-3, wherein the gasket in the height direction of the sealing can is pressed between the front Kikata peripheral wall of the exterior can battery.   5. The flat battery according to claim 1, wherein an angle θ <b> 2 formed by the flat portion and the straight portion is 92 degrees or more in a single state before the sealing can is assembled.   In a single state before assembly of the sealing can, if an angle formed by the flat portion and the straight portion is an angle θ2, an angle difference θ3 between the angle θ2 and the angle θ1 is 0.5 ° or more and 5 ° or less. The flat battery according to any one of claims 1 to 5.

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