KR100684845B1 - Storage battery and method for manufacturing armor body of the same and apparatus for forming armor body of the same - Google Patents

Abstract

It is to make uniform the elongation of the raw material which occurs at the time of manufacture of the exterior body used for an electrical storage device.

In shaping the exterior of the electrical storage device by drawing the sheet member 25, the sheet member 25 is placed between the male 23 of the molding apparatus 20 and the bag 29. . The bag 29 is inflated with high pressure air, and the receiving portion is formed in accordance with the shape of the male 23 while gradually pressing the sheet member 25 from the center of the bottom portion 23a of the male 23. After storing a battery element in this accommodating part, electrolyte is inject | poured and it seals.

Forming apparatus, sheet material, drawing

Description

Manufacturing method of power storage device and external body of power storage device and molding apparatus of external body of power storage device

1 is a perspective view of a power storage device according to an embodiment of the present invention.

2 is a perspective view showing a developed shape of the exterior body.

3 is a sectional view showing a schematic configuration of a molding apparatus.

4 is a view for explaining a molding step, showing a state in which part of the sheet material is deformed.

5 is a view showing a state in which the sheet material is molded.

6 is a plan view of a molded article.

7 is a sectional view showing a schematic configuration of a molding apparatus.

8 is a view for explaining a molding step, showing a state in which a part of the sheet member is deformed.

Fig. 9 is a sectional view showing a schematic configuration of a molding apparatus having fine holes in a male mold.

Fig. 10 is a sectional view showing a schematic configuration of a molding apparatus having fine holes in a female mold.

* Description of the symbols for the main parts of the drawings *

1: power storage device 2: outer body

3: battery element 10: receiving portion

23: Male 24, 43: Mounting portion

25: sheet material 27, 45: intake and exhaust holes (holes, supply means)

28: fluid pump 29, 46: bag (expansion body)

41: female 52, 64: fine hole

The present invention relates to a power storage device capable of accumulating electrical energy, a method of manufacturing an exterior body, and a molding apparatus for an exterior body of the power storage device.

BACKGROUND OF THE INVENTION As an electric energy source used for portable electronic devices such as mobile phones, power storage devices such as nonaqueous secondary batteries and electric double layer capacitors have been developed. Such a power storage device is manufactured by inserting a battery element in which a separator is inserted between an anode electrode and a cathode electrode in an exterior body, and then filling and sealing a polymer gel electrolyte in the exterior body.

Here, the outer package is a package composed of a laminate of a soft metal film such as aluminum foil and a plastic film such as nylon, and has a recessed portion in which the laminate is drawn with a die and a punch.

The three-dimensional curvature is formed in the corner part of this recessed part, and in order to form such curvature, the punch is formed with the curvature equivalent to half of the thickness of a battery element, ie, half of drawing quantity (for example, patent document 1 ( Japanese Patent Application Laid-Open No. 2000-133216).

However, in the conventional manufacturing method, when drawing the exterior body, the sheet material of the portion corresponding to the corner portion of the concave portion by the punch is mainly extended, so that after the drawing, the film thickness between the central portion and the corner portion of the exterior body. The difference was huge.

In particular, when the drawing amount is large, the aluminum foil becomes thin, and when the film thickness is less than 20 µm, for example, pin holes, cracks, and wrinkles are likely to occur. As described above, as a conventional manufacturing method, there is a problem that the amount of drawing and the shape of molding are restricted by the elongation of the base metal.

This invention is made | formed in view of such a situation, The objective is to make uniform the increase of the material which arises at the time of manufacture of an exterior body. Moreover, it is providing the exterior body manufactured in this way, and the electrical storage device containing an exterior body.

The present invention for solving the above problems is to form a concave accommodating portion in a sheet material to manufacture an exterior body, and to accommodate a battery element having an electrode in the accommodating portion of the exterior body to produce an electrical storage device. A method for manufacturing an outer body of a power storage device for manufacturing the outer body, wherein the sheet member is placed between a mold made of a rigid body manufactured in accordance with the shape of the housing portion and an inflatable expandable body, and a fluid is applied. The expansion of the expander to pressurize the sheet member, and expand the expander larger than the outer shape of the mold part of the mold, thereby deforming the sheet member to conform to the shape of the mold. Way.

In this manufacturing method, shaping | molding is performed so that a sheet | seat material may be gradually pressed to a mold by expansion | expansion of an expansion body. For this reason, unlike the case where the sheet | seat material extends substantially evenly, and the vicinity of a corner part extends intensively like conventionally, the thickness of a corner part does not become remarkably thin.

In this manufacturing method, after the sheet member is deformed to conform to the shape of the mold, the inflated body is shrunk, and then fluid can be supplied to the micropores opened on the surface of the mold. In addition, the sheet member may be sucked by the micropores that are expanded on the surface of the mold while expanding the inflatable body.

When the fluid is supplied to the micropores after the processing, the molded sheet material in close contact with the mold is pressurized, so that separation from the mold is promoted. In addition, when the sheet material is sucked from the micropores during processing, the sheet material is easily deformed in conformity with the shape of the mold.

Then, when the battery element and the electrolyte are enclosed in the outer case manufactured by the manufacturing method of the outer case of the electric storage device, a power storage device is obtained.

Moreover, as a shaping | molding apparatus for realizing such a manufacturing method, an exterior body is manufactured by shape | molding the accommodating part of a sheet | seat material, and the battery element which accommodates the battery element provided with an electrode in the said accommodating part is produced in this exterior body, and manufactures an electrical storage device. An apparatus for forming an exterior body of an electrical storage device for manufacturing the exterior body, the apparatus comprising: a mold made of a rigid body made to fit the shape of the housing portion, an expandable body expandable to cover an outer shape of the molding portion of the mold, and the mold. And a mounting portion for placing the sheet member between the inflatable bodies and a supplying means capable of injecting fluid into the inflatable body.

Such a molding apparatus may be provided with the pressurization mechanism which has the microhole opened to the surface of the said mold, and the fluid pump which can discharge a fluid to the said microhole. Moreover, when the said mold is a female type | mold, you may be provided with the pressure reduction mechanism which has the microhole which penetrates this female mold, and the fluid pump which can suck the fluid in the said microhole.

And the electrical storage device manufactured in this way is shape | molded the accommodating part in the sheet | seat material, accommodated the said battery element in the said accommodating part, and then to the electrical storage device which sealed the said accommodating part in the cover part which consists of the said sheet | seat material. Wherein the thickness ratio of the bottom center of the receptacle to the thickness of the lid is between 0.7 and 0.9, and the thickness ratio of the bottom edge of the bottom of the receptacle to the thickness of the lid is between 0.7 and 0.9. The thickness and the thickness of the bottom edge of the receiving portion are approximately equal.

Best Mode for Carrying Out the Invention The present invention will be described in detail with reference to the drawings.

(First embodiment)

As shown in FIG. 1, the electrical storage device 1 is sealed with the battery element 3 and electrolyte in the exterior body 2. As shown in FIG. The battery element 3 is a laminate in which a separator is sandwiched between a positive electrode and a negative electrode. The positive electrode terminal lead 4 extends from the positive electrode, and the negative electrode terminal lead 5 extends from the negative electrode. 4 and 5 are drawn out from the exterior 2.

As shown in FIG. 2, the exterior body 2 has a main body portion 11 in which a receiving portion 10 is concave in a central portion, and the edge of the receiving portion 10 has a smooth curved shape. One edge which is bent and extends here to connect a pair of side edge portions 12, 13 parallel in the longitudinal direction of the body portion 11 and one end of these side edge portions 12, 13. The part 14 is formed. From the remaining edge of the accommodating part 10 and the other end of each side edge part 12 and 13, the cover part 15 which has the external shape substantially equivalent to the main body part 11 is integrally connected, and is formed. .

The accommodating part 10 has the wall part 16 continuous to each edge part 12, 13, and 14, and the bottom part 17 is continuous in the wall part 16. As shown in FIG. The wall 16 and the bottom 17 and the boundary have a gentle curved shape. The size of the bottom part 17 is smaller than the opening of the accommodating part 10, and the accommodating part 10 is substantially trapezoid in cross section. The four corners of the bottom portion 17 are corner portions 18 having a three-dimensional curved shape.

The exterior body 2 is made of a sheet material in which a fusion layer, a metal layer, and a protective layer are laminated. As such a sheet | seat material, the aluminum laminate film which a metal layer consists of an aluminum thin film is mentioned, for example. In this case, the fusion layer and the protective layer are made of a thermoplastic resin such as flute, and the film thickness thereof is, for example, 40 µm. The metal layer is made of a metal thin film having soft and ductility, such as aluminum, and the film thickness is 40 micrometers, for example.

In FIG. 3, the schematic diagram of the exterior body 2 shaping | molding apparatus is shown. The molding apparatus 20 has an upper base 21 and a lower base 22. The upper base 21 is supported by a lifting mechanism (not shown) so as to be movable in the vertical direction, and on the lower surface thereof, a metallic male 23 having an outer shape that is substantially the same as the inner shape of the receiving portion 10 (see FIG. 2). ) Is fixed. The lower base 22 has a mounting surface 24 thereon, and fixing means (not shown) for positioning and fixing the sheet member 25, which is a material of the exterior body 2, is mounted thereon. have. Moreover, the recessed part 26 is formed larger than the male 23 in the position of the center of the lower base 22, and also below the male 23. As shown in FIG. An intake and exhaust hole 27 is formed in the center of the recess 26, and a fluid pump 28 is connected to the intake and exhaust hole 27, so that a fluid such as high pressure water or gas can be supplied and drawn in. It is.

In addition, a bag-shaped bag 29 is fixed to the recess 26 to cover the intake and exhaust holes 27. The bag 29 is made of, for example, a silicone resin, urethane rubber, or the like, and is made of an elastic body that can be stretched into a substantially spherical shape when the fluid is supplied therein, and the maximum diameter at that time is sufficiently larger than that of the male 23. The bag 29 is surface-treated so that its outer surface has a predetermined coefficient of friction.

Next, the manufacturing process of the electrical storage device 1 is demonstrated centering on the molding process of the exterior body 2.

First, after raising the upper base 21 shown in FIG. 3, the sheet | seat material 25 is placed in the mounting part 24 so that the recessed part 26 may be covered by the lower base 22. As shown in FIG. Thereafter, the upper base 21 is lowered to bring the male 23 close to the sheet member 25. Further, the fluid is discharged from the fluid pump 28 to supply a high pressure fluid into the bag 29 through the intake and exhaust holes 27. This causes the bag 29 to expand to fill the recess 26. Then, as shown in Fig. 4, the upper center of the bag 29, which can be relatively freely inflated, presses up the center of the sheet member 25, and the sheet member 25 is raised from the bottom surface of the male 23 ( Press in the center of 23a) to make contact.

In addition, as the bag 29 expands, the contact area between the sheet member 25 and the male 23 gradually increases, and the sheet member 25 is extended substantially uniformly, thereby being molded along the shape of the male 23. The sheet member 25 is molded in a predetermined amount according to the male 23, and the fixing means of the mounting portion 24 releases the edge portion of the sheet member 25 so that the edge portion of the sheet member 25 has an upper base portion ( 21). And as shown in FIG. 5, when the bag 29 covers the outer periphery of the male 23, and the accommodating part 10 is shape | molded so that the sheet | seat material 25 may fit the shaping | molding part outer shape of the male 23, Shrink (29).

Since the sheet | seat material 25 remains on the male 23 side after shaping | molding, when this is removed from the male 23 and trimming is carried out, it becomes the molded article 30 as shown in FIG. The molded article 30 is connected to the main body 11, the lid 15, and one side edge portion 12 of the main body 11, which is later formed as the exterior body 2. Which consists of a substantially rectangular shape.

The molded part 30 is placed so that the bottom part 17 of the accommodating part 10 is lowered, and the terminal elements 4 and 5 of the battery element 3 manufactured by a separate process extend beyond one edge part 14. It is accommodated to go out of the molded article 30. Next, the lid part 15 is folded back and the lid part 15 is overlapped with the main body part 11 so as to cover the main body of the battery element 3, and the other side edge part 13 and the lid part ( 15) and the edge portion 14 and the lid portion 15 are fused together. Since one side edge part 12 side is open, electrolyte solution is inject | poured here and gas removal is carried out, and the one side edge part 12 and the lid part 15 are fused together. After trimming the speech section 31, the fusion section of the lateral edge section 12 and the cover section 15 and the fusion section of the lateral edge section 13 and the cover section 15 are housed. When bent to comply with the above, the electrical storage device 1 shown in FIG. 1 is completed.

In this embodiment, since the bag 29 is inflated to press the sheet member 25 to inflate the drawing, the drawing is performed near the center of the portion corresponding to the bottom 17 of the receiving portion 10. Since the sheet material 25 can be molded while extending substantially evenly, the film thickness of the bottom part 17 becomes substantially constant irrespective of a place. Furthermore, since the sheet member 25 extends evenly, the difference between the minimum film thickness (bottom 17) and the maximum film thickness (cover 15) of the exterior body 2 becomes smaller than before. For example, in the case where the initial film thickness of the metal layer of the sheet member 25 is 40 μm, the film thickness at the center of the bottom 17 after molding and the film thickness of the corner portion 18 of the bottom 17 are equally 35 μm. do. Moreover, since the film thickness of the cover part 15 is not shape | molded, it is 40 micrometers intact. Although the film thickness differs also by molding depth etc., in any case, the film thickness of the center part 18 of the bottom part 17 and the corner part 18 of the bottom part 17 is substantially the same after shaping | molding. Based on the film thickness of the cover part 15, it can obtain between 0.7 and 0.9.

In addition, when the shaping angle of the male mold 23 is 5 degrees and the radius of the corner portion 23b is 1.5 mm, the yield rate at which a pinhole or the like does not occur even when the molding depth is about 5 mm is obtained. You can do it around 90%. Therefore, the high quality exterior body 2 can be manufactured efficiently. Moreover, with the conventional manufacturing method, such molding depth cannot be realized or the yield falls considerably. According to this embodiment, the sheet member 25 can be molded into a shape that has not been realized in the past.

In addition, in such a molding apparatus 20, since the sheet member 25 can be processed by the deformation of the bag 29, the change of the magnitude | size of the accommodating part 10, and the thickness change of the sheet | seat material 25 are carried out. It can respond flexibly. Moreover, since the shape of the male 23 can be made into the shape of a molded article like the conventional mold, the workability of the male 23 is improved. In addition, since it is not necessary to provide a pressurizing mechanism for pressurizing the mold which is a heavy object at a predetermined pressure, the structure of the molding apparatus can be simplified and further downsized.

And the electrical storage device 1 manufactured using such an exterior body 2 can enlarge the capacity | capacitance of the battery element 3 by deepening the accommodating part 10, and can enlarge a battery capacity. In addition, since the incidence rate of pinholes or the like in the exterior body 2 is greatly reduced, the quality is increased.

(2nd Example)

As shown in FIG. 7, the shaping | molding apparatus 40 is equipped with the metal mold 41 which is a lower body rigid metal, and the upper base 42 which can be elevated. The upper surface of the male mold 41 is a mounting portion 43 on which the sheet member 25 is placed. In addition, the female mold 41 is formed with a recess 44 having an inner shape that is joined to the outer shape of the receiving portion 10 (refer to FIG. 2), and the upper base 42 is located above the center of the recess 44. An intake and exhaust hole 45 is formed at a fitting position. The fluid pump 28 is connected to this intake and exhaust hole 45. The bag 46 is fixed to the upper base 42 so as to cover the intake and exhaust holes 45. The bag 46 is an inflatable body that can fill the recess 44 upon inflation. In addition, other apparatus structures, such as the material of the bag 46, are as above.

In manufacture of the exterior body 2, after placing the sheet | seat material 25 in the female mold 41, the upper base 42 is dropped, and the bag 46 is gradually expanded with the high pressure fluid. As shown in FIG. 8, the bag 46 pushes the sheet | seat material 25 into the recessed part 44 gradually increasing the contact area with the sheet | seat material 25 near the center part of the sheet | seat material 25. As shown in FIG. When the bag 46 expands to fill the recess 44, the bag 10 is molded so as to be sandwiched between the bag 46 and the recess 44. At this time, the corner part 18 of the accommodating part 10 is formed by the curved corner part 44a formed in the corner part of the recessed part 44. Thereafter, the bag 46 is reduced, the sheet member 25 is separated from the female mold 41, and trimmed, whereby a molded article 30 as shown in Fig. 6 is obtained. Other processes are the same as the above.

According to this embodiment, since the shaping | molding apparatus 40 shape | molds the sheet | seat material 25 by the metal female 41 and the bag 46 made of metal, manufacture of a metal mold | die becomes easy. Other effects are the same as in the first embodiment. For example, when the angular angle of the female mold 41 is 5 degrees and the radius of the corner portion 41a is 1.5 mm, the limit molding depth can be about 6 mm. In addition, when the molding depth is 5 mm, the yield rate at which no pinhole or the like occurs is 90% or more.

(Third Embodiment)

As shown in Fig. 9, the molding apparatus 50 according to this embodiment has a male 51 having an outer shape that is substantially equivalent to the inner shape of the receiving portion 10 of the exterior body 2, and the male 51 The plurality of fine holes 52 are formed at predetermined intervals, for example, at equal intervals so as to open toward the lower base 22. These micropores 52 are connected to a pressurized fluid pump 53. Such a male 51 can be made of, for example, a sintered metal such as nickel, and the fine holes 52 in this case are formed by continuous bubbles. The rest of the configuration is the same as in the first embodiment.

In manufacturing the exterior body 2, air is uniformly discharged from the fluid pump 53 to all the fine holes 52 in a state where the sheet member 25 remains on the male 51 side after molding. In the fine holes 52, the bottom opening of the male 51 is covered with the sheet material 25, so that the internal pressure of the fine holes 52 increases. This internal pressure acts in the direction of removing the receiving portion 10 from the male mold 51, and as a result, the sheet member 25 is separated from the mold. Other manufacturing processes are as above. According to this embodiment, since the pressurizing mechanism made up of the fine hole 52 and the fluid pump 53 is provided on the male mold 51 side, the mold can be easily separated from the mold and the productivity can be improved. . In addition, the yield rate at which pinholes and the like do not occur is improved than in the first embodiment. In addition, the diameter of the fine hole 52 is a magnitude | size which does not break the sheet | seat material 25 at the time of shaping | molding, For example, it is preferable that it is about several ten micrometers.

(Example 4)

As shown in Fig. 10, the molding apparatus 60 used in this embodiment has a two-ply structure in which the female mold 61, which is a lower mold, is laminated with the second portions 6 and 3 on the first portion 62. Have. And the recessed part 44 is formed so that a part of 1st part 62 may be recessed through the 2nd part 63. FIG. This recessed portion 44 has an inner shape that is approximately equal to the outer shape of the housing portion 10 of the exterior body 2. Further, the plurality of fine holes 64 are formed in the first portion 62 at substantially equal intervals so as to be open to the bottom portion 44b of the recess 44. These minute holes 64 are connected to a pressurized fluid pump 65. The first portion 62 can be made of, for example, a sintered metal such as nickel, and in this case, the fine holes 64 are formed by continuous bubbles. Moreover, the 2nd part 63 becomes a mounting part of the sheet | seat material 25, and is manufactured from the metal plate which has airtightness which does not have a fine hole. In addition, the female mold 61 is also covered with an airtight member (not shown) leaving the outer periphery and the lower portion of the first portion 62 with the fine holes 64, so that the airtightness is maintained except for the fine holes 64. Consists of. The rest of the configuration is the same as in the second embodiment.

In manufacture of the exterior body 2, after the bag 46 is reduced after shaping | molding, the pressurization mechanism which consists of the fluid pump 65 and the fine hole 64 is operated. Specifically, air is supplied to the fine holes 64 by the fluid pump 65. Since the opening is closed by the sheet member 25, the fine hole 64 acts to extrude the sheet member 25, whereby the sheet member 25 after molding is separated from the mold. According to this embodiment, since the pressurizing mechanism is provided on the female mold 61 side, separation from the mold becomes easy, and productivity can be improved. In addition, the yield rate at which no pinholes or the like occurred was improved as compared with the second embodiment. In addition, the diameter of the fine hole 64 is preferably about the same as in the third embodiment.

Moreover, in this shaping | molding apparatus 60, the pressure reduction mechanism can be comprised by the fine hole 64 and the fluid pump 65 by making the fluid pump 65 into a pressure reduction type pump. In this case, during molding, the fluid pump 65 depressurizes the recess 44 through the fine hole 64. As a result, the sheet member 25 is attracted and easily deformed according to the shape of the recess 44. In particular, since the sheet member 25 is easily deformed following the shape of the corner portion 44a of the concave portion 44, the sheet member 25 is drawn more uniformly, resulting in uniformity and shape accuracy of the film thickness. Is improved. In this way, when the exterior body 2 is molded, the yield rate at which no pinholes or the like is generated is improved compared to the second embodiment, and is close to 100%.

In the case of the pressure reduction mechanism, in addition to the fine holes 64, the fine holes 70 may be provided so as to be opened in the side wall of the recess 44. At first, suction is started from the fine hole 64 provided on the bottom 44b side, and the fine hole 64 provided on the edge portion side of the bottom 44 gradually and the fine hole provided on the corner 44a side therefrom. (64), like the fine hole 70 provided in the wall part, you may gradually expand the suction range. In addition, suction can also be performed only by the fine holes 64 and 70 provided in the vicinity of the corner portion 44a.

Moreover, in this shaping | molding apparatus 60, the fluid pump 65 is comprised so that pressurization and pressure reduction are possible, and it can be set as the structure which has a pressurization mechanism and a pressure reduction mechanism. In this case, the molding assists the molding of the sheet member 25 as a pressure reducing mechanism, and when separating from the post-molding mold, the assisting mechanism assists the separation from the mold of the sheet material 25 as a pressing mechanism. The uniformity and shape accuracy of the film thickness can be improved by the pressure reduction mechanism, and the separation from the mold can be speeded up by the pressure mechanism. In this case, a yield ratio in which pinholes and the like do not occur is close to 100%, thereby improving productivity.

In addition, this invention can be applied widely without being limited to each said Example.

For example, the first portion 62 of the male 51 or the female 61 having the fine holes 52 can be made of a porous material, for example, pumice stone. In addition, the shape of the bags 29 and 46 can be made into the cone shape which makes the intake-exhaust hole 27 and 45 side bottom, a square spindle shape, and a cube shape.

Moreover, the pressure reduction mechanism can be provided in the shaping | molding apparatus 20, 50 provided with the male 23, 51. In this case, the sheet member 25 is sucked into the corner portion (by sucking the air in the gap formed in the corner portion 23b of the sheet member 25 and the male bodies 23 and 51 pressed by the bag 29). Aspiration is carried out at 23b).

According to this invention, since the film thickness of the accommodating part of the exterior body which comprises an electrical storage device becomes substantially uniform, generation | occurrence | production of a crack, a wrinkle, and a pinhole can be prevented. In addition, by sucking the sheet material during molding of the exterior body, it is possible to improve the shape accuracy and shorten the processing time. When the molded article is pressed after molding of the exterior body, separation from the mold can be accelerated, and processing time can be shortened. Moreover, since the shaping | molding apparatus which concerns on this invention is comprised so that shaping | molding to the mold which consists of an inflated body and a rigid body may be carried out, only one mold which consists of rigid bodies can reduce the cost of an apparatus. Further, since the inflatable body is smaller and lighter than the mold, the device can be miniaturized.

Claims (9)

In the power storage device manufactured by molding a receiving portion having a concave shape in a sheet material and accommodating a battery element having an electrode in the receiving portion, the method for manufacturing the exterior body, The sheet member is placed between a mold made of a rigid body manufactured according to the shape of the housing portion and an expandable inflatable body, By injecting a fluid to expand the expander to pressurize the sheet material, and expand the expander larger than the outer shape of the molding portion of the mold, The manufacturing method of the exterior of an electrical storage device which deform | transforms the said sheet material so that it may correspond to the shape of the said die | dye. According to claim 1, And deforming the sheet member to conform to the shape of the mold, and then contracting the inflatable body, and supplying a fluid to the micropores opened on the surface of the mold. The method according to claim 1 or 2,  A method for manufacturing an exterior of a power storage device, in which the inflatable member is inflated and the sheet member is sucked into a fine hole that is opened in the surface of the mold. The electrical storage device which seals a battery element and electrolyte in the exterior body manufactured by the manufacturing method of the exterior body of the electrical storage device of Claim 3. An exterior of a power storage device for manufacturing the exterior body is produced by forming a recessed portion in a sheet material to manufacture an exterior body, and in accommodating a battery element having an electrode in the housing portion to produce a power storage device. As a molding apparatus of the sieve, A mold made of a rigid body manufactured according to the shape of the receiving part; An inflatable expandable to cover the outer shape of the mold of the mold; A mounting portion for placing the sheet member between the mold and the inflatable body; Apparatus for shaping the exterior of a power storage device, comprising supply means capable of injecting fluid into the inflatable body. The method of claim 5, And a pressurizing mechanism having a microhole opened on the surface of the mold and a fluid pump capable of discharging fluid into the microhole. The method of claim 5 or 6, The mold is a female mold, and the apparatus for forming an exterior body of a power storage device, comprising a pressure reducing mechanism having a fine hole penetrating the female mold and a fluid pump capable of sucking the fluid in the micro hole. In the electrical storage device in which the accommodating portion is formed in a sheet material, the battery element is accommodated in the accommodating portion, and the accommodating portion is sealed in a lid portion made of the sheet material. The thickness ratio of the center of the bottom of the receptacle to the thickness of the lid is between 0.7 and 0.9, The thickness ratio of the bottom edge of the receiving portion to the thickness of the lid is between 0.7 and 0.9, The electrical storage device of which the thickness of the center of the bottom part of the said accommodating part is equal to the thickness of the bottom edge part of the said accommodating part. An electricity storage device comprising a battery element and an electrolyte enclosed in an exterior body manufactured by the method for manufacturing an exterior body of the power storage device according to claim 1.

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