JP2010073473A - Flat battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat battery advantageous for achieving high capacity while ensuring sealing capability. <P>SOLUTION: The flat battery 1 is formed by sealing the opening of an outer can 2 with a sealing can 3, the outer can 2 and the sealing can 3 have a cylindrical shape formed by standing the surrounding wall in the periphery of a bottom and opening one end, the tip 12a of a surrounding wall 12 of the outer can 2 is bent toward the center axis 9 of the outer can 3, the outer can 2 is crimped to the sealing can 3, a surrounding wall 16 of the sealing can 3 is a single wall having no turning up part in the cross section shape in the center axis 9 direction of the sealing can 3, a surrounding wall 16 of the sealing can 3 has a straight line part 17 connecting to the bottom 15 through a corner part 18, and the Vickers hardness of the straight part 17 is larger than that of the corner part 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

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. 14 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.

  15 is a cross-sectional view taken along line CC of 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. 15, when the tip 104 a of the peripheral wall 104 of the outer can 101 is bent 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 shape with one end open, and the distal end of the peripheral wall of the outer can is curved toward the central axis 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 that is not folded back, and the peripheral wall of the sealing can forms a straight portion connected to the bottom via a corner portion. The Vickers hardness of the straight portion is larger than the Vickers hardness of the corner portion.

  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 sealing can has a Vickers hardness of the straight portion larger than the Vickers hardness of the corner portion. Therefore, during caulking, deformation of both the corner portion and the straight portion is suppressed, and the gasket Sealability is maintained.

  In the flat battery of the present invention, it is preferable that the corner portion has a Vickers hardness of 150 or more, and the linear portion has a Vickers hardness of 200 or more.

  Moreover, it is preferable that the Vickers hardness of the said linear part is 1.05 times or more of the Vickers hardness of the said corner part.

  Moreover, it is preferable that the said linear part is work-hardened by the process which compresses the said linear part.

  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.

  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 bottom portion 15 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 bottom 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.

  Although the schematic configuration of the flat battery 1 has been described above, the flat battery 1 according to the present embodiment is characterized by the hardness distribution of the sealing can 3. Specifically, in the sealing can 3 of FIG. 3, the Vickers hardness of the linear portion 17 is made larger than the Vickers hardness of the corner portion 18. As will be described in detail later, this prevents the straight portion 17 of the sealing can 3 from being deformed and secures the sealing performance by the gasket 4 during the caulking process for bending the distal end portion 12a of the peripheral wall 12 of the outer can 2. It is to do.

  Here, the Vickers hardness is a hardness measured according to JISZ2244. At the time of measurement, a diamond square conical indenter having a diagonal surface of 136 degrees is used to form a dent on the test surface, and the surface area of the permanent dent is obtained from the diagonal length of the permanent dent. The Vickers hardness is obtained from the value obtained by dividing the indented test load by the surface area of the permanent indentation.

  Hereinafter, a molding method for obtaining the hardness distribution of the sealed can 3 will be described with reference to FIGS. FIG. 4 shows a state in which the disk-like member 41 is punched from the plate 40 that is the raw material of the sealing can 3. The disk-shaped member 41 is processed by a transfer press. The transfer press is a press machine that includes a die corresponding to each of the multi-steps and a transfer mechanism that transports a workpiece to the next step. The disk-like member 41 is processed by a mold corresponding to each process and formed into the shape shown in FIG.

  FIG. 5 shows the change in the shape of the workpiece after each step. Each figure of (a)-(e) has shown the top view and sectional drawing. FIG. 5A shows a disk-like member 41. As described above, the disc-like member 41 is punched from the plate member 40 as shown in FIG. In FIG. 5B, the disk-like member 41 is processed into a cylindrical shape in which a peripheral wall 43 is erected on the outer periphery of the bottom portion 42 by drawing.

  FIG. 5C shows a state after the hitting process. Although the state of FIG. 5C does not change to being cylindrical, the height of the peripheral wall 43 is adjusted by hitting the peripheral wall 43.

  By this height adjustment, the peripheral wall 43 is compressively deformed and work hardened. As described above, in the sealing can 3 according to the present embodiment, the Vickers hardness of the straight portion 17 is larger than the Vickers hardness of the corner portion 18. This is due to work hardening in the tapping process. FIG. 5D shows a state in which the shoulder portion 45 is formed by processing the corner portion 44 of the processed product of FIG. FIG. 5E shows a completed state after finishing.

  The completed sealing can has the same shape as the sealing can 3 shown in FIG. As described above, the Vickers hardness of the straight portion 17 is larger than the Vickers hardness of the corner portion 18 due to the hitting process.

  On the other hand, the sealing can 3 shown in FIG. 3 can also be formed by press working with a progressive die. However, in this processing method, a tapping step cannot be included, and the sealed can 3 in which the Vickers hardness of the straight portion 17 is larger than the Vickers hardness of the corner portion 18 cannot be obtained.

  Hereinafter, a method for forming a sealed can with a progressive die will be described as a comparative example. FIG. 6 shows a plan view of the coil material 50 being processed by the progressive die. FIG. 6 also shows a cross-sectional view of the workpiece. Each cross-sectional view is a cross-sectional view in the width direction of the coil material 50 (a cross-sectional view taken along the line BB).

  In FIG. 6, by sending the coil material 50 for one step (in the direction of arrow a), each workpiece of (a), (b), (c) is one step ahead (b), (c), Sent to position (d). In this state, it is processed into a cross-sectional shape at each position through a press for one stroke. That is, every time the coil material 50 is fed for one stroke, multi-step pressing proceeds simultaneously.

  The disk-shaped member 51 of (a) is processed into the drawn shape of (b). The narrowed corner portion 52 of (b) is processed as shown in (c), and a shoulder portion 53 is formed. The workpiece processed in the state of (c) is punched out of the broken line portion in (d) and is separated from the coil material 50. The workpiece cut from the coil material 50 is folded back at the upper end 54 as shown in (e) to form a shape corresponding to the folded-back portion 107 in FIG. The step (e) can be omitted, and the peripheral wall can be a single wall without a folded portion.

  In the forming method shown in FIG. 6, the processing proceeds while the workpiece is integrated with the coil material 50. This molding is the same as the molding method shown in FIG. 5 in that work hardening is obtained at the corner 52 by bending.

  However, in the molding method shown in FIG. 6, there is no step of compressing the peripheral wall of the cylindrical member. For this reason, when the sealing can 3 shown in FIG. 3 is formed by the forming method shown in FIG. 6, the Vickers hardness of the linear portion 17 is smaller than the Vickers hardness of the corner portion 18. The magnitude relationship of the Vickers hardness is opposite to that of the sealed can 3 molded by the molding method shown in FIG.

  This will be described below with reference to experimental results. FIG. 7 shows measurement points of Vickers hardness of Example 1 and Comparative Example 1. FIG. 7A shows a main part of the sealing can 3 according to the first embodiment. Example 1 is a sealing can for coin-shaped batteries having a diameter of 20 mm and a height of 5 mm. The sealing can 3 of Example 1 is the same structure as the sealing can 3 shown in FIG. 3, and the side wall part 16 is a single wall without a folding | turning part. Further, Example 1 was formed by the forming method shown in FIG. 5, and was formed by proceeding to a workpiece punched into a disk shape.

  FIG. 7B shows the main part of the sealing can 102 according to the comparative example 1. Comparative Example 1 is a sealing can for coin-shaped batteries having a diameter of 24.5 mm and a height of 5 mm. The sealing can 102 of Comparative Example 1 has the same configuration as the sealing can 102 shown in FIG. 15, and a folded portion 107 is formed on the side wall portion 105. Further, Comparative Example 1 is formed by the forming method shown in FIG. 6, and is formed by proceeding processing to a workpiece integrated with the coil material 50.

  FIG. 8 shows the relationship between measurement points and Vickers hardness for Example 1 and Comparative Example 1. A solid line 60 indicates the first embodiment, and a broken line 61 indicates the first comparative example. In both Example 1 and Comparative Example 1, the hardness at point B (corner part) is higher than that at points A and A ′ (bottom part). This is considered to be due to work hardening by bending of the corner portion. The same applies to points D and F that are corner portions of Example 1 and Comparative Example 1, and H point of Comparative Example 1 that is a bent portion.

  Here, the work hardening extends not only to the bent portion but also to the vicinity thereof. For this reason, in Example 1, it is thought that work hardening reaches also in the C point, E point, and G point which are the corner vicinity. Further, in Example 1, the entire peripheral wall is work-hardened by the hitting process, and is work-hardened also at the point H away from the corner portion.

  In Comparative Example 1, work hardening occurs at points C and E near the corner, and work hardening also occurs at point G near both the corner (F point) and the bent portion (H point). It will be.

  Therefore, both Example 1 and Comparative Example 1 maintain a high value between point B and point H.

  On the other hand, when the Example 1 and the Comparative Example 1 are compared between the points B and H, the hardness of the Example 1 (solid line 60) is almost entirely over the hardness of the Comparative Example 1 (broken line 61). However, it is getting bigger. In particular, in Comparative Example 1 (broken line 61), point C (straight line portion 111) has a lower hardness than point B (corner portion 108), whereas in Example 1 (solid line 60), point C ( The hardness of the straight portion 17) is higher than that of the point B (corner portion 18).

  This is considered to be due to the difference between the molding methods. That is, the difference in magnitude between the hardnesses of point B and point C in Example 1 and Comparative Example 1 is that, as described above, in Example 1, work hardening by the tapping process of FIG. 5C is obtained. On the other hand, in Comparative Example 1, it is considered that there is no process corresponding to the hitting process.

  Here, in FIG. 2, the distal end portion 12 a of the peripheral wall 12 of the outer can 2 is curved in the direction of the central axis 9. Thus, the outer can 2 is caulked and fixed to the sealed can 3. If the hardness of the point C (straight line portion 17) is higher than that of the point B (corner portion 18) as in the first embodiment, the deformation of the straight portion 17 of the sealing can 3 is suppressed, and the gasket 4 This is advantageous for ensuring sealing performance. Details of this will be described below with reference to FIGS. 2 and 13 after the manufacturing process has been described with reference to FIGS.

  When assembling the components shown in FIG. 3, the assembly is performed with the top and bottom of FIG. 3 turned upside down. FIG. 9 shows a cross-sectional view of the state during assembly. FIG. 9A 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. 9B shows a state where the power generation element 10 is stored in the sealing 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. 10 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. 10 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. 11 is a cross-sectional view showing a state before caulking. The flat battery 1 shown in FIG. 10 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. As a result, the tip 12 a of 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. 12 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.

  In the state of the finished product after the caulking process in FIG. 2, the front 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. During this bending process, an external force is applied to the peripheral wall 16 of the sealing can 3 so as to deform the peripheral wall 16 toward the central axis 9 side. When the peripheral wall 16 is deformed toward the central axis 9, the peripheral wall 16 is displaced away from the gasket 4. As a result, the sealing performance by the gasket 4 is lowered.

  In Comparative Example 1, as shown in FIG. 15, the folded portion 107 is formed to increase the strength, thereby preventing the sealing performance from being lowered. On the other hand, in the single-walled peripheral wall without the folded-back portion 107, the entire peripheral wall is displaced toward the central axis, which is disadvantageous for ensuring sealing performance.

  Specifically, in the configuration of FIG. 2, the corner portion 18 is work-hardened by bending. Even if the corner portion 18 with increased hardness is not deformed during the caulking process, if the straight portion 17 is deformed, the entire peripheral wall 16 that is a single wall is displaced toward the central axis 9 side, and the sealing performance by the gasket 4 is ensured. Disadvantageous.

  On the other hand, in the configuration of FIG. 2, if not only the corner portion 18 of the sealing can 3 but also the hardness of the straight portion 17 of the peripheral wall 16 is increased, the central axis of the entire peripheral wall 16 even if the peripheral wall 16 is a single wall. The displacement to the 9 side can be suppressed, and the deterioration of the sealing performance can be prevented.

  As described above, in Example 1, the hardness of the straight portion 17 is larger than the hardness of the corner portion 18. That is, when the Vickers hardness of the corner portion 18 of the sealing can 3 is Hv1, and the Vickers hardness of the linear portion 17 is Hv2, the sealing can 3 according to the present embodiment satisfies the relationship of the following formula (1). ing.

Formula (1) Hv1 <Hv2
According to this configuration, the hardness of the corner portion 18 is increased by work hardening after bending, and the hardness of the linear portion 17 is further increased than that of the corner portion 18. Therefore, at the time of caulking, deformation of both the corner portion 18 and the straight portion 17 can be suppressed, and deterioration in sealing performance can be prevented.

  In order to ensure the effect of the formula (1), it is preferable to satisfy the relationship of the following formula (2). In Example 1 of FIG. 8, the value of the point C (straight line portion 17) is about 1.15 times the value of the point B (corner portion 18), and the sealing performance is ensured. Considering this point, the range of the following formula (3) is more preferable.

Formula (2) 1.05 <= Hv2 / Hv1
Formula (3) 1.10 ≦ Hv2 / Hv1
On the other hand, in consideration of the limit of work hardening by tapping, Hv2 / Hv1 is preferably within the range of the following formula (4).

Formula (4) Hv2 / Hv1 ≦ 1.6
The numerical example of the ratio between Hv1 and Hv2 has been described above. Preferred numerical ranges of Hv1 and Hv2 are as follows. The material of the sealing can 3 is usually a stainless material such as SUS430, and the following numerical range is derived from the degree of work hardening by bending of the corner portion in SUS430 and the degree of work hardening by tapping.

  The Vickers hardness Hv1 of the corner portion 18 is preferably in the range of the following formula (5), more preferably in the range of the following formula (6), and further preferably in the range of the following formula (7).

Formula (5) 150 <= Hv1
Formula (6) 170 <= Hv1
Formula (7) 190 <= Hv1
The Vickers hardness Hv2 of the linear portion 17 is preferably in the range of the following formula (8), more preferably in the range of the following formula (9), and further preferably in the range of the following formula (10).

Formula (8) 200 <= Hv2
Formula (9) 210 <= Hv2
Formula (10) 220 <= Hv2
On the other hand, it is difficult to increase the hardness of the corner portion 18, and when the hardness of the corner portion 18 is too high, it becomes difficult to make the hardness of the straight portion 17 larger than that of the corner portion 18. For this reason, it is preferable to make the hardness of the corner part 18 into the range of following formula (11), and it is more preferable to set it in the range of following formula (12).

Formula (11) Hv1 ≦ 210
Formula (12) Hv1 <= 200
Next, the present embodiment will be compared with a comparative example with reference to FIG. FIG. 13A is a cross-sectional view of a main part of a flat battery 100 according to a comparative example. This figure has the same configuration as the conventional example shown in FIG. FIG.13 (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 this movement corresponds to FIG. In the flat battery 1 in FIG. 13B, the inner peripheral surface of the sealing can 3 is moved outward by a dimension A as compared to the flat battery 100 in 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. 13B, 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, the flat battery 1 satisfies the relationship of the above formula (1), the corner portion 18 is increased in hardness by work hardening after bending, and the straight portion 17 is the corner portion. This means that the hardness is further increased than 18.

  Therefore, in the present embodiment, while the peripheral wall 16 of the sealing can 3 is a single wall, the deformation of both the corner portion 18 and the straight portion 17 can be suppressed during the caulking process, and the sealing performance by the gasket 4 is ensured. Can do.

  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 figure which shows the state which punched the disk-shaped member from the board | plate material which concerns on one embodiment of this invention. The figure which shows the change of the shape of the workpiece which passed through each process which concerns on one embodiment of this invention. The figure which shows the molding method of the sealing can which concerns on a comparative example. The figure which shows the measurement point of the Vickers hardness of Example 1 and Comparative Example 1. The figure which shows the relationship between a measurement point and Vickers hardness about Example 1 and Comparative Example 1. 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.9 (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. 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 CC 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 Bottom part of sealed can 16 Perimeter wall of sealed can 17 Straight part of sealed can 18 Corner part of sealed can 19 Shoulder part of sealed can

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,
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 peripheral wall of the sealing can forms a straight part connected to the bottom part through a corner part,
2. The flat battery according to claim 1, wherein the straight portion has a Vickers hardness greater than that of the corner portion.   2. The flat battery according to claim 1, wherein the corner portion has a Vickers hardness of 150 or more, and the linear portion has a Vickers hardness of 200 or more.   3. The flat battery according to claim 1, wherein a Vickers hardness of the linear portion is 1.05 times or more a Vickers hardness of the corner portion.   The flat battery according to any one of claims 1 to 3, wherein the straight portion is work-hardened by a process of compressing the straight portion.   The flat battery according to any one of claims 1 to 4, 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.   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 the gasket in the height direction of the sealing can The flat battery according to claim 1, wherein is pressed.

Images