TW201824610A - Power storage device exterior case and production method therefor - Google Patents

Abstract

Provided is a power storage device exterior case whereby a large distortion focused on a trihedral angular portion can be suppressed sufficiently, the occurrence of a wrinkle or a crack can be suppressed, and strength can be secured sufficiently. The invention has a configuration comprising: a housing case 2 shaped as an approximately polygonal column and having an open bottom surface; and a flanged portion extending outward in an approximately horizontal direction from the peripheral border of the opening at the housing case bottom surface. Adjacent side walls 11 constituting the housing case are joined by a corner wall portion 4 disposed therebetween and having a curved surface. Each edge of a ceiling wall 12 constituting the housing case is joined to an upper edge 11a of the corresponding side wall through a ridge line portion 5 having a curved surface, each corner border 12b of the ceiling wall 12 is joined to an upper border 4a of the corresponding corner wall portion 4 through a corner summit portion 6 provided with a curved surface. The configuration has the relationship: curvature radius R1 of the ridge line portion 5 < curvature radius R2 of the angle summit portion 6 in a vertical cross section.

Description

 Outer casing for power storage device and method of manufacturing same  

The present invention relates to a power storage device such as a battery or a capacitor used in a portable device such as a smart phone or a touch panel, a hybrid vehicle, an electric vehicle, a wind power generation, a solar power generation, or a nighttime electric storage battery. External casing and its manufacturing method.

Further, in the scope of the patent application of the present invention and the present specification, the term "slightly rectangular shape" is used in the sense of "slightly cubic shape".

Further, in the scope of the patent application of the present invention and the present specification, the term "slightly polygonal column shape" is used in the sense of "a polygonal column shape having a slightly positive polygonal shape on the bottom surface". In addition, the above-mentioned "slightly rectangular column shape" is used in the meaning of the above-mentioned "slightly rectangular shape".

In addition, in the present specification, with respect to the outer casing, the word "above" means the direction from the bottom opening of the outer casing toward the top wall of the housing case (the upward direction in Fig. 7); Word means the direction from the top wall of the receiving casing toward the opening of the bottom surface (the direction downward in FIG. 7); the word "horizontal" means the direction parallel to the surface of the top wall of the receiving casing; The term means the direction perpendicular to the surface of the top wall of the containment casing.

In addition, in this specification, with respect to a punch press, the word "above" means the direction in which the punch enters the hole of the die at the time of forming (refer to FIG. 5); the word "below" means completely opposite to the above. Direction; the word "horizontal" means the direction parallel to the surface of the top wall (forming surface) of the punching machine; the term "vertical" means the direction perpendicular to the surface of the top wall of the punching machine.

Lithium ion batteries, for example, have been widely used as power sources for notebook computers, video cameras, mobile phones, and the like. This lithium ion secondary battery is composed of a member surrounded by a material other than the periphery of the battery main body portion (including the positive electrode, the negative electrode, and the main body of the electrolyte). The outer surface of the main body of the power storage device such as the battery main body is externally mounted. For example, it is known that the inner layer formed of the heat resistant resin film, the aluminum foil layer, and the thermoplastic resin film are sequentially integrated. (refer to Patent Document 1).

In addition, the power storage device is housed in a housing peripheral portion (flange portion) in which the peripheral edge of the bottom opening of the storage case having a rectangular parallelepiped shape in which the bottom surface is opened, and which is extended to the outside in the horizontal direction. The outer casing is placed on the bottom surface side of the housing casing so as to overlap the planar shape, and the sealing peripheral portion of the outer casing is thermally welded (heat-sealed) to the peripheral edge portion of the planar outer casing to be sealed. Sealing by such heat sealing engagement prevents leakage of the electrolyte.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-22336

However, the outer casing is formed by deep-stretching or the like for a flat outer casing (see Patent Document 1), but the skew is concentrated (concentrated) in the housing portion during molding. Among the three corners formed by the side walls of the adjacent pair and the top wall, there is a problem that wrinkles or cracks are likely to occur in the corner faces of the outer casing, and it is difficult to ensure sufficient strength. In particular, the deeper molding is performed to further increase the height (depth) of the housing case, and when the outer casing is externally mounted, wrinkles or cracks are formed in the trihedral portion, and the strength is lowered.

The present invention has been made in view of the related art, and an object of the present invention is to provide an exterior casing for a power storage device and a method of manufacturing the same, which can sufficiently suppress a large skew from concentrating on a trihedral portion and suppress wrinkles or cracks. Fully ensure strength.

In order to achieve the foregoing objects, the present invention provides the following technical means.

[1] An outer casing for an electrical storage device, comprising: a housing case having a slightly polygonal column shape with a bottom surface open; and a flange portion extending from a peripheral edge of the opening of the bottom surface of the housing case to a laterally outward direction The outer casing for the power storage device is characterized in that the adjacent side walls of the storage casing are connected to each other by a corner wall portion disposed on a curved surface of each other; and each side of the top wall constituting the storage casing is guided by Each of the upper side walls and the ridge line portion of the curved surface are connected; the corner edges of the top wall are connected by the upper edge of the corner wall portion and the corner apex portion having the curved surface; the radius of curvature of the ridge portion In the case of "R ₁ ", when the radius of curvature of the vertical section of the corner apex portion is "R ₂ ", the relationship of R ₁ &lt; R ₂ is satisfied.

[2] The outer casing for a power storage device according to the first aspect, wherein the slightly polygonal column shape is a substantially rectangular parallelepiped shape. In other words, the invention of the second aspect of the invention is an outer casing for a power storage device, comprising: a housing case having a substantially rectangular parallelepiped shape with a bottom surface open; and an outer side of the opening of the bottom surface of the housing case in a slightly horizontal direction a flange portion extending; the feature is that the adjacent side walls of the housing case are connected by a corner wall portion disposed on a curved surface of each other; and the four sides of the top wall of the housing case are formed by individual The edge of the upper side wall and the ridge line of the curved surface are connected; the four corner edges of the top wall are connected by the upper edge of the individual corner wall portion and the corner apex portion having the curved surface; the radius of curvature of the ridge portion is "R ₁ ", when the radius of curvature of the vertical section of the apex portion of the corner is "R ₂ ", the relationship of R ₁ &lt; R ₂ is satisfied.

[3] The outer casing for a power storage device according to the above aspect, wherein the edge of the ridge portion in the horizontal direction and the edge of the corner apex facing the edge are via a transfer wall Connected.

[4] The outer casing for a power storage device according to the above-mentioned item 3, wherein at least a part of a boundary ridge line between the transfer wall portion and the top wall is curved outward in a plan view.

[5] The outer casing for a power storage device according to the above aspect, wherein the length of the transfer wall portion in the horizontal direction is more than 0 mm and not more than 5 mm.

The outer casing for a power storage device according to any one of the preceding claims, wherein the housing case and the flange portion are formed of a laminated material, and the laminated material includes A sealing layer in which a metal foil layer and a surface on one side of the metal foil layer are laminated.

[7] A power storage device, comprising: a power storage device main body portion, and an outer casing outer casing member for a power storage device according to any one of the preceding claims 1 to 6, wherein the power storage device main body portion is The exterior component is externally mounted.

[8] A method for producing an outer casing for a power storage device, which is a method for producing an outer casing for a power storage device by stretching a material plate using a mold for forming a strand, the die for forming a stretch forming mold comprising: a punching machine a slightly polygonal column shape formed by inserting a material sheet; a hard mold having a hole having a slightly polygonal column shape that is inserted into a material plate of the punching machine; and a pressure plate having a hole inserted into the punching machine; The manufacturing method of the outer casing comprises: a sandwiching step of sandwiching the material plate between the sandwich layer around the hole of the hard mold and the interlayer of the hole of the pressure plate; forming step, Inserting the punching machine into the hole of the die plate and further entering the hole of the die, thereby forming the material plate to form an outer casing for the power storage device; and the punching machine is disposed adjacent to the sidewall Connected to the corner wall portions of the curved surfaces of each other; the sides of the top wall are connected by the upper side of the side wall and the ridge line of the curved surface; each of the top walls The corner edge is a punch that is connected to the upper edge of the corner wall portion and the apex portion of the curved surface; and the manufacturing method of the outer casing for the power storage device is: the radius of curvature of the ridge portion is "S ₁ ", when the radius of curvature of the vertical section of the corner apex portion is "S ₂ ", the punch satisfying the relationship of S ₁ <S ₂ .

[9] The method for producing an outer casing for a power storage device according to the above aspect, wherein the slightly polygonal column shape is a substantially rectangular parallelepiped shape. In other words, the invention of the above [9] is a method of manufacturing a storage case for an electric storage device by using a jig for forming a jigsaw, and the jig for forming a wrap forming machine includes a punching machine a slightly rectangular shape formed by being inserted into a three-dimensional shape; a hard mold having a hole having a substantially rectangular parallelepiped shape for receiving a material plate pushed into the punching machine; and a pressure plate having a hole inserted into the punching machine; and the method of manufacturing the outer casing of the electricity storage device, The method comprises: a sandwiching step of sandwiching the material sheet between the sandwich layer around the hole of the hard mold and the interlayer of the hole of the pressure plate; forming step by using the punching machine from the foregoing Inserting the hole of the pressure plate into the hole of the hard mold, and forming the material plate to form an outer casing for the power storage device; the punching machine is disposed at a corner of the curved surface of the adjacent side wall Connected to the wall; the four sides of the top wall are connected by the upper side of the side wall and the ridge line of the curved surface; the four corners of the top wall are separated by individual On the edge of the corner wall and includes a curved corner portion are connected to the vertices of the punch; and using the system: the radius of curvature of the ridge line portion is "S _1", the vertical cross section of a radius of curvature of the vertex angle "S _2" At the time, the punch that satisfies the relationship of S ₁ <S ₂ .

[10] The method for producing an outer casing for a power storage device according to the above aspect of the present invention, wherein the edge of the ridge portion in the horizontal direction and the corner apex portion facing the edge The end edges are connected by a transfer wall.

According to the inventions of [1] and [2], the corner portion of the curved surface, the ridge line portion of the curved surface, and the corner apex portion of the curved surface are provided in the accommodating case portion, and the radius of curvature R ₁ < the apex portion of the ridge line portion is satisfied. Since the relationship of the relationship between the curvature radius R ₂ of the vertical cross section is sufficient, it is possible to sufficiently suppress the large skew from concentrating on the trihedral portion (dispersible skew) of the accommodating outer casing portion, and it is possible to provide wrinkles or cracks at the trihedral corner portion and to provide sufficient The outer casing is insulated. Therefore, it is possible to provide an exterior casing having a deeper housing portion.

According to the invention of [3], since the edge of the ridge portion in the horizontal direction and the edge of the apex portion of the corner opposite to the edge are connected by the transfer wall portion (continuous connection is made at the transfer wall portion), Further, the skew of the three corners of the housing portion is sufficiently dispersed, and the strength of the outer casing can be further sufficiently ensured. Therefore, it is possible to provide an outer casing having a deeper housing portion.

According to the invention of [4], since at least a part of the boundary ridge line between the transfer wall portion and the top wall is curved outward in the plan view, the stress of the transfer wall portion can be further reduced.

According to the invention of the fifth aspect, since the length of the transfer wall portion in the horizontal direction is more than 0 mm and 5 mm or less, the skew which is concentrated on the three corners of the housing case portion can be further sufficiently dispersed, and the outer casing can be further improved. The strength of the outer casing.

According to the invention of [6], it is possible to provide an exterior casing which is excellent in heat sealability and excellent in gas barrier properties.

According to the invention of the seventh aspect, since the outer casing is provided with a sufficient strength to prevent wrinkles or cracking, it is possible to provide a power storage device having excellent durability. Further, since the outer casing can be formed deeper without any problem, the electric capacity (battery capacity, etc.) of the power storage device can be further increased.

According to the inventions of [8] and [9], since the punching is performed by using a punching machine, and the punching machine is provided with a corner wall portion of a curved surface, a ridge line portion of a curved surface, and an angular apex portion of the curved surface, the radius of curvature S of the ridge portion is satisfied. _{1 "} The punching of the relationship between the radius of curvature S ₂ of the vertical section of the apex of the corner, so that the outer casing for the electrical storage device can be manufactured, and the outer casing for the electrical storage device can sufficiently suppress the large skew from concentrating on the three corners of the housing portion. (Dispersible skew) to prevent wrinkles or cracks in the trihedral corner and to have sufficient strength.

According to the invention of [10], since the edge of the ridge line portion in the horizontal direction of the punching machine and the edge of the apex portion of the corner opposite to the end edge are connected by the transfer wall portion, it is possible to manufacture further sufficient strength. Exterior casing.

1‧‧‧Outer casing for power storage device

2‧‧‧ containment enclosure

3‧‧‧Flange

4‧‧‧ corner wall

4a‧‧‧Upper edge

5‧‧‧ ridgeline

5c‧‧‧ edge

6‧‧‧ corner apex

6c‧‧‧ edge

7‧‧‧Transfer wall

11‧‧‧ side wall

11a‧‧‧上上

12‧‧‧ top wall

12b‧‧‧ corner

13‧‧‧Bottom opening

14‧‧‧Boundary ridge

29‧‧‧External parts

30‧‧‧Power storage device

31‧‧‧Power storage unit body

40‧‧‧Molding for forming

41‧‧‧hard mode

41a‧‧‧ Hole

41b‧‧‧ clip level

42‧‧‧Billing plate

42a‧‧‧ Hole

42b‧‧‧ clip level

43‧‧‧ Punch

44‧‧‧ corner wall

44a‧‧‧Upper edge

45‧‧‧ ridgeline

45c‧‧‧ edge

46‧‧‧ corner apex

46c‧‧‧ edge

47‧‧‧Transfer wall

51‧‧‧ side wall

51a‧‧‧上上

52‧‧‧ top wall

52b‧‧‧ corner

R ₁ ‧‧‧The radius of curvature of the vertical section of the ridgeline of the outer casing

R ₂ ‧‧‧The radius of curvature of the vertical section of the apex of the outer casing

L‧‧‧The length in the horizontal direction of the transfer wall of the outer casing

S ₁ ‧‧‧The radius of curvature of the vertical section of the ridgeline of the punch

S ₂ ‧‧‧The radius of curvature of the vertical section of the apex of the corner of the punch

M‧‧‧ Length in the horizontal direction of the transfer wall of the punch

Fig. 1 is an exploded perspective view showing an embodiment of a mold for forming a strand used in the production method of the present invention.

Fig. 2 is a perspective view showing a corner wall portion of the punching machine obliquely from the obliquely lower side and its vicinity.

Fig. 3 is a plan view showing the apex portion of the corner of the punch and its vicinity.

Fig. 4 is a side view showing the apex portion of one corner of the punch and its vicinity.

Fig. 5 is a schematic cross-sectional view showing a state in which a material (material sheet) other than the mold for forming a strand for drawing is used.

Fig. 6 is a perspective view showing an embodiment of an exterior casing for a power storage device according to the present invention.

Fig. 7 is a sectional view taken along line B-B of Fig. 6.

FIG. 8 is a perspective view showing a corner wall portion of the outer casing of the power storage device in the outer casing of the power storage device, which is obliquely viewed from the obliquely oblique side view, and its vicinity (although the flange portion is omitted).

Fig. 9 is a plan view showing the apex portion of the accommodating case and its vicinity in the outer casing for the electrical storage device of Fig. 6 (however, the flange portion is omitted).

Fig. 10 is a side view showing the apex portion of the housing case and its vicinity in the outer casing for the electrical storage device of Fig. 6 (however, the flange portion is omitted).

FIG. 11 is a perspective view showing a corner wall portion of a housing case and its vicinity in an outer casing for an electrical storage device according to another embodiment of the present invention, which is obliquely viewed from the obliquely downward side (however, the flange portion is omitted).

Fig. 12 is a plan view showing the apex portion of the housing case and its vicinity in the outer casing for the electrical storage device of Fig. 11 (however, the flange portion is omitted).

Fig. 13 is a side view showing the apex portion of the housing case and its vicinity in the outer casing for the electrical storage device of Fig. 11 (however, the flange portion is omitted).

Fig. 14 is a cross-sectional view showing an example of a laminated structure of a material sheet (outer material) used in the production method of the present invention.

Fig. 15 is a cross-sectional view showing an embodiment of a power storage device of the present invention.

A method of manufacturing an outer casing for a power storage device according to the present invention will be described. An embodiment of the forming die 40 used in the present manufacturing method is as shown in Fig. 1 .

The above-described wrap forming mold 40 includes a punching machine 43 for stereoscopically molding the material sheet 91 by pressing the material sheet 91, and the hard mold 41 having a hole having a substantially rectangular parallelepiped shape for receiving the material sheet 91 of the punching machine 43. 41a; the pressure plate 42 has a hole 42a (see FIG. 1) inserted into the substantially rectangular parallelepiped shape of the punch 43.

The punch 43 has a substantially rectangular parallelepiped shape (see Fig. 1). The punch 43 has four side walls 51, a top wall 52, and a bottom wall 53 (see Figs. 2 to 4). Any of the side wall 51, the top wall 52, and the bottom wall 53 is slightly rectangular. In the punching machine 43, the adjacent side walls 51 are connected (continuously connected) by the corner wall portions 44 disposed on the curved surfaces of each other; the four sides of the top wall 52 (four sides forming a rectangular shape) are individually The upper side 51a of the side wall 51 and the ridge line 45 of the curved surface are connected (continuously connected); the four corners 52b of the top wall 52 are formed by the upper edge 44a of the corner wall 44 and the corner of the curved surface. The vertices 46 are connected (continuously connected). Each of the corner wall portion 44, the ridge portion 45, and the corner apex portion 46 has a curved surface that protrudes outward (a curved surface that expands outward) (see FIGS. 2 to 4). Further, any of the corner wall portion 44, the ridge portion 45, and the corner apex portion 46 is formed as a quarter arc (a portion of a quarter of a circle) in the middle of the cross-sectional view (see FIGS. 2 to 4). .

Further, the edge 45c of the horizontal direction of the ridge portion 45 (the direction parallel to the longitudinal direction of the ridge portion 45) and the edge 46c of the corner apex portion 46 opposite to the end edge 45c are transferred. The wall portion 47 is connected (continuously connected). The transfer wall portion 47 has a curved surface that protrudes outward (a curved surface that expands outward). The upper edge of the transfer wall portion 47 is connected (continuously connected) to the top wall 52, and the lower edge of the transfer wall portion 47 is connected (continuously connected) to the side wall 51 (see Figs. 2 to 4). The transfer wall portion 47 has a configuration in which the radius of curvature from the side of the corner apex portion 46 toward the side of the ridge portion 45 is gradually reduced.

In the punching machine 43 of the present embodiment, at least a part of the ridge line (boundary ridge line) 54 at the boundary between the transfer wall portion 47 and the top wall 52 in a plan view is a curve that protrudes outward (a curve that expands outward) (see the figure). 3). Further, in the present embodiment, the side of the corner apex portion 46 of the boundary ridge line 54 in the plan view is a straight line, and the side of the ridge line portion 45 of the boundary ridge line 54 is curved outward (the curve which expands outward) (refer to the figure). 3).

In the punching machine 43 of the present embodiment, at least a portion of the ridge line (boundary ridge line) 55 at the boundary between the transfer wall portion 47 and the side wall 51 in a side view is a curve that protrudes upward (a curve that expands upward) (refer to Figure 4). Further, in the present embodiment, the side of the corner apex portion 46 of the boundary ridge line 55 is a straight line in the side view, and the side of the ridge line portion 45 of the boundary ridge line 55 is curved upward (the curve which expands upward) (refer to the figure). 4).

In the punching machine 43, the radius of curvature of the vertical section of the ridge portion 45 is "S ₁ ", and when the radius of curvature of the vertical section of the corner apex portion 46 is "S ₂ ", the relationship of S ₁ <S ₂ is satisfied. . By using the punch 43 satisfying such a relationship, it is possible to sufficiently suppress the large skew from concentrating on the trihedral corner portion of the accommodating outer casing portion 2, thereby producing an outer casing 1 which can prevent wrinkles or cracks at the trihedral corner portion and have sufficient strength. .

In the punching machine 43, the length M of the horizontal direction of the transfer wall portion 47 (the direction parallel to the longitudinal direction of the ridge portion 45) is preferably more than 0 mm and not more than 6 mm (see Figs. 3 and 4).

In the punching machine 43, the radius of curvature (S ₁ ) of the vertical cross section of the ridge portion 45 is preferably in the range of 0.05 mm to 4 mm (see Figs. 3 and 4). Further, "S ₂ -S ₁ " (the difference between S ₂ minus S ₁ ) is preferably in the range of 0.1 mm to 4 mm. Further, the radius of curvature (S ₃ ) of the horizontal cross section of the corner wall portion 44 is preferably in the range of more than 0 mm and not more than 8 mm (see Fig. 4).

In the punching machine 43, the relationship of the relationship of M ≧ 2 (S _{2 -} S ₁ ) / π is preferably used. In this case, the acute angle portion in the punch 43 can be reduced, and the stress applied during forming can be sufficiently dispersed. Avoiding concentration, which further enhances formability.

Therefore, the outer casing 1 for a power storage device of the present invention can be manufactured by using the above-described butt molding die 40 having the above configuration. First, the material sheet 91 is sandwiched between the sandwich layer 41b around the hole 41a of the hard mold 41 and the interlayer 42b around the hole 42a of the pressure plate 42 (interlayer step). Next, as shown in FIG. 5, the punch 43 is inserted from the hole 42a of the die plate 42 and further into the hole 41a of the die 41, and the material plate 91 is stretched and formed, as shown in FIG. The outer casing 1 is used for the electrical storage device.

In the present embodiment, the material sheet (outer material) 91 is made of a laminate, and the laminate includes a heat-resistant resin layer 92 on the outer layer, a seal layer 93 on the inner layer, and a metal foil disposed between the two layers. Layer 94 (see Fig. 14). In the present embodiment, the material (outer material) 91, the surface (upper surface) on one side of the metal foil layer 94, the second adhesive layer (outer adhesive layer) 95 and the heat resistant resin layer ( The outer layer) 92 is integrated, and the surface (the lower surface) of the other side of the metal foil layer 94 is laminated and integrated with the first adhesive layer (inner adhesive layer) 96 and the sealing layer (inner layer) 93. (Refer to Figure 14). Further, the material plate (outer material) 91 may be a laminate material, and the laminate material includes a metal foil layer 94 and a sealing layer (inner layer) 93 of an area layer on one side of the metal foil layer 94.

The outer casing 1 for a storage device of the present invention includes a housing case 2 having a substantially rectangular parallelepiped shape in which the bottom surface is opened, and a flange portion 3 extending from the periphery of the opening port 13 of the bottom surface of the housing case 2 to the outer side in the horizontal direction. (Refer to Figures 6 and 7).

The housing case 2 has substantially the same shape as the upper portion of the punch 43 (see Figs. 6 and 7). That is, the housing case 2 has four side walls 11 and a top wall 12 (see FIGS. 8 to 10). Any of the side wall 11 and the top wall 12 is slightly rectangular. In the housing case 2, the adjacent side walls 11 are connected (continuously connected) by the corner wall portions 4 arranged on the curved surface of each other; the four sides of the top wall 12 (four sides forming a rectangular shape) are The upper edge 11a of the side wall 11 and the ridge line portion 5 of the curved surface are connected (continuously connected); the four corner edges 12b of the top wall 12 are provided by the upper edge 4a of the corner wall portion 4 The corner vertices 6 of the curved surface are connected (continuously connected). Each of the corner wall portion 4, the ridge portion 5, and the corner apex portion 6 has a curved surface that protrudes outward (a curved surface that expands outward) (see FIGS. 8 to 10). Further, any of the corner wall portion 4, the ridge portion 5, and the corner apex portion 6 is formed as a quarter arc (a portion of one-fourth of a circle) in the middle of the cross-sectional view (see FIGS. 8 to 10). ).

Further, the end edge 5c of the ridge portion 5 in the horizontal direction (the direction parallel to the longitudinal direction of the ridge portion 5) and the edge 6c of the corner apex portion 6 opposed to the end edge 5c are transferred. The wall portion 7 is connected (continuously connected). The transfer wall portion 7 has a curved surface that protrudes outward (a curved surface that expands outward). The upper edge of the transfer wall portion 7 is connected (continuously connected) to the top wall 12, and the lower edge of the transfer wall portion 7 is connected (continuously connected) to the side wall 11 (see Figs. 8 to 10). The transfer wall portion 7 has a configuration in which the radius of curvature gradually decreases from the corner apex portion 6 side toward the ridge portion 5 side.

In the present embodiment, the outer casing 1 is externally mounted, and at least a part of the ridge line (boundary ridge line) 14 at the boundary between the transfer wall portion 7 and the top wall 12 is a curve which protrudes outward (expanded to the outside). Curve) (Refer to Figure 9). Further, in the present embodiment, in the plan view, the corner apex portion 6 side of the boundary ridge line 14 is straight, and the ridge line portion 5 side of the boundary ridge line 14 is curved outward (curved outward). Figure 9).

In the outer casing of the present embodiment, at least a portion of the ridgeline (boundary ridgeline) 15 at the boundary between the transition wall portion 7 and the side wall 11 is a curve that protrudes upward (the upward expansion curve). ) (Refer to Figure 10). Further, in the present embodiment, the side of the corner apex portion 6 of the boundary ridge line 15 is straight in the side view, and the ridge line portion 5 side of the boundary ridge line 15 is curved upward (curved curve upward) (refer to the curve) Figure 10).

In the outer casing 1, the radius of curvature of the vertical section of the ridge portion 5 is "R ₁ ", and when the radius of curvature of the vertical section of the corner apex portion 6 is "R ₂ ", it satisfies R ₁ <R ₂ Relationship. Since the relationship is satisfied, the outer casing 1 can sufficiently suppress the large skew from concentrating on the three corners of the housing case 2, and can prevent the wrinkles or cracks of the trihedral corners and have sufficient strength.

In the outer casing 1, the length L of the horizontal direction of the transfer wall portion 7 (the direction parallel to the longitudinal direction of the ridge portion 5) is preferably more than 0 mm and not more than 5 mm. In this case, the outer casing 1 can be further sufficiently fully The dispersion is concentrated on the skew of the three corners of the housing case 2, so that the outer casing 1 is more excellent in strength.

In the outer casing 1, the radius of curvature (R ₁ ) of the vertical cross section of the ridge portion 5 is preferably in the range of 0.1 mm to 4 mm (see Figs. 9 and 10). Further, "R _{2 -} R ₁ " (the difference between R ₂ minus R ₁ ) is preferably in the range of 0.1 mm to 4 mm. Further, the radius of curvature (R ₃ ) of the horizontal section of the corner wall portion 4 is preferably in the range of 0.1 mm to 8 mm (see Fig. 10).

In the outer casing 1 described above, it is preferable to adopt a configuration in which the relationship of L ≧ 2 (R _{2 -} R ₁ ) / π is established, and by forming the shape, the stress at the time of molding can be sufficiently dispersed to avoid concentration. .

The trihedral portion of the other embodiment of the exterior casing 1 for an electrical storage device according to the present invention and its vicinity are shown in Figs. In this embodiment, the configuration other than the transfer wall portion 7 is the same as that of the above embodiment. In the above embodiment, the transfer wall portion 7 of the accommodating case 2 is configured in two stages as shown in Figs. 8 to 10 (in the plan view, the apex portion 6 side of the boundary ridge line 14 is straight, and the ridge line portion 5 of the boundary ridge line 14 is formed. The side is convex toward the outer side, and in the side view, the side of the apex portion 6 of the boundary ridge line 15 is straight, and the side of the ridge line portion 5 of the boundary ridge line 15 is formed by a curve that protrudes upward. However, this embodiment In the case of head-up, the boundary ridge line 14 is a straight line, and in the side view, the boundary ridge line 15 is a straight line (Figs. 11 to 13). In the case of the two-stage configuration of the above-described embodiment, the advantage of the stress of the transfer wall portion 7 can be further reduced. Therefore, the configuration of the above embodiment is preferable, but it may be configured as shown in Figs. Therefore, it is a matter of course that the punch 43 described above can also be constructed in the same segment.

Further, in the manufacturing method of the above embodiment, the punch 43 has a substantially rectangular parallelepiped shape (see Fig. 1), but may have a polygonal column shape (e.g., a slightly polygonal column shape having a low height). The shape of the slightly polygonal column is not particularly limited, and examples thereof include a slightly pentagonal column shape, a slightly hexagonal column shape, a slightly hexagonal column shape, a slightly octagonal column shape, a slightly pentagonal column shape, and a slightly pentagonal column shape. At this time, the plan view shape of the hole 41a of the die 41 is a slightly polygonal shape which is the same as the bottom surface of each of the slightly polygonal column shapes.

Therefore, by performing the same steps as those of the above-described embodiment using the punch 43 having a slightly polygonal column shape, the following outer casing 1 for a power storage device can be obtained. In other words, the outer casing 1 for a power storage device obtained includes a housing case 2 having a slightly polygonal column shape with a bottom surface open, and a convex portion extending from the periphery of the opening of the bottom surface of the housing case 2 to the outer side in the horizontal direction. The edge portion 3; the adjacent side wall 11 constituting the housing case 2 is connected by the corner wall portion 4 disposed on the curved surface of each other; and the sides of the top wall 12 constituting the housing case 2 are individually The upper side 11a of the side wall 11 and the ridge line part 5 of the curved surface are connected; the corner edges 12b of the top wall 12 are connected by the upper edge 4a of the corner wall portion 4 and the corner apex portion 6 having a curved surface; The radius of curvature of the vertical section of the ridge portion 5 is "R ₁ ", and when the radius of curvature of the vertical section of the corner apex portion 6 is "R ₂ ", the relationship of R ₁ <R ₂ is satisfied. Since the relationship of R ₁ &lt; R ₂ is satisfied, the outer casing 1 can sufficiently suppress the large skew from concentrating on the trigonal corner portion of the accommodating outer casing portion 2, and can prevent wrinkles or cracks of the trihedral corner portion and have sufficient strength. Further, the slightly polygonal column shape of the housing case 2 (for example, a slightly polygonal column shape having a low height) corresponds to a shape of a slightly polygonal column of the punch 43 (for example, a slightly polygonal column shape having a low height). The shape of the polygonal column of the housing case 2 is not particularly limited, and examples thereof include a slightly pentagonal column shape, a slightly hexagonal column shape, a slightly hexagonal column shape, a slightly octagonal column shape, a slightly octagonal column shape, and a slightly octagonal column shape. For example, when the housing case 2 has a hexagonal column shape, the corner wall portion 4 is present at six places, the corner apex portion 6 is present at six places, and the ridge line portion 5 is also present at six places.

In the present invention, the sealing layer (inner layer) 93 is excellent in chemical resistance to an electrolytic solution or the like which is used in a lithium ion battery or the like, and is required to impart heat sealing properties to the exterior material. .

The resin constituting the sealing layer 93 is not particularly limited, and examples thereof include a hot-melt resin. The hot-melt resin is not particularly limited, and examples thereof include polyethylene, polypropylene, ionomer, ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EAA), and ethylene methyl methacrylate resin (EMMA). ), ethylene-vinyl acetate copolymer resin (EVA), anhydrous maleic acid modified polypropylene, anhydrous maleic acid modified polyethylene, and the like. Among them, the sealing layer 93 is preferably formed of a non-stretched polyolefin.

The thickness of the sealing layer (inner layer) 93 is preferably set within a range of 15 μm to 30 μm. When the thickness is 15 μm or more, sufficient heat sealing strength can be ensured, and when it is 30 μm or less, it contributes to thin film formation and weight reduction.

In the present invention, the heat-resistant resin constituting the heat-resistant resin layer (outer layer) 92 is a heat-resistant resin that is not melted by a heat-sealing temperature when the exterior material is heat-sealed. The heat resistant resin is preferably a heat resistant resin having a melting point higher than the melting point of the sealing layer 93 by 10 ° C or higher, and a heat resistant resin having a melting point higher than the melting point of the sealing layer 93 by 20 ° C or higher is particularly preferable.

The heat-resistant resin layer (outer layer) 92 is not particularly limited, and examples thereof include a polyamide film such as a nylon film, a polyester film, and the like, and such a stretched film is preferably used. The heat-resistant resin layer 92 is a biaxially stretched polyimide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, or a biaxially oriented polyethylene terephthalate. Diester (PET) films or biaxially stretched polyethylene naphthalate (PEN) films are particularly preferred. The nylon film is not particularly limited, and examples thereof include a nylon film, a 6,6 nylon film, and an MXD nylon film. Further, the heat-resistant resin layer 2 may be formed of a single layer, or may be formed of, for example, a polyester film/polyamide film (a layer formed of a PET film/nylon film). Further, in the case of the above-mentioned stratification, it is preferred to arrange the polyester film side on the outermost side. The heat resistant resin layer 92 may be formed by coating and drying a heat resistant resin.

The thickness of the heat resistant resin layer (outer layer) 92 is preferably 2 μm to 50 μm. The thickness of the polyester film is preferably 5 μm to 40 μm, and the thickness of the nylon film is preferably 15 μm to 50 μm. By setting it to the above-mentioned appropriate lower limit or more, it is possible to ensure that the outer casing has sufficient strength, and by setting it to the above-mentioned appropriate upper limit or less, the stress at the time of molding can be reduced, and the formability can be further improved.

In the present invention, the metal foil layer 94 is responsible for imparting gas barrier properties against the intrusion of oxygen or moisture into the outer casing 1. The metal foil layer 94 is not particularly limited, and examples thereof include an aluminum foil, a SUS foil (stainless steel foil), a copper foil, a nickel foil, and a titanium foil. Among them, an aluminum foil is preferably used. The thickness of the metal foil layer 94 is preferably 15 μm to 100 μm. When the metal foil is produced, the occurrence of pinholes during rolling can be prevented, and when it is 100 μm or less, the stress during molding can be reduced, and the moldability can be improved. The thickness of the metal foil layer 94 is preferably 15 μm to 45 μm. Further, the aluminum foil is preferably an A8079-O material or an A8021-O material specified in JIS H 4160:2006.

It is preferable that the metal foil layer 94 is subjected to a chemical conversion treatment at least on the inner surface (the surface on the second adhesive layer 96 side). By performing such chemical conversion treatment, corrosion of the surface of the metal foil due to the contents (electrolyte of the battery, etc.) can be sufficiently prevented. Examples of the chemical conversion treatment include chromate treatment and the like.

The first adhesive layer (outer adhesive layer) 95 is not particularly limited, and examples thereof include a polyurethane polyolefin adhesive layer, a polyurethane adhesive layer, a polyester polyurethane adhesive layer, and a polyether polyurethane adhesive layer. The thickness of the first adhesive layer 95 is preferably 1 μm to 6 μm.

The second adhesive layer (inner adhesive layer) 96 is not particularly limited. For example, the first adhesive layer 95 can be used, but a polyolefin system having less swelling due to an electrolytic solution can be used. The agent is preferred. Among them, an acid-denatured polyolefin-based adhesive is particularly preferred. The acid-modified polyolefin-based adhesive agent may, for example, be a maleic acid-modified polypropylene binder or a fumaric acid-modified polypropylene binder. The thickness of the second adhesive layer 96 is preferably 1 μm to 5 μm.

An embodiment of the power storage device 30 constructed by using the outer casing 1 for a power storage device of the present invention is shown in Fig. 15 . This power storage device 30 is a lithium ion battery. In the present embodiment, as shown in FIG. 15, the exterior casing 1 and the outer casing (the planar shape in which the material plate 91 is not formed) 28 are formed by the outer casing 1 for the electricity storage device. Therefore, in the housing recessed portion (accommodating case 2) of the outer casing 1 for the electrical storage device of the present invention, the main body portion (electrochemical device or the like) 31 of the power storage device having a substantially rectangular parallelepiped shape is accommodated, and above the main body portion 31 of the electric storage device, The inner layer 93 side of the planar outer casing 28 is disposed on the inner side (lower side), and the peripheral portion of the inner layer 93 of the planar outer casing 28 and the outer casing 1 are convexly sealed by heat sealing. The inner layer 93 of the edge portion (the peripheral portion for sealing) 3 is hermetically sealed and sealed to constitute the power storage device 30 of the present invention (see FIG. 15). Moreover, the inner surface of the housing recessed portion of the outer casing 1 is an inner layer (sealing layer) 93, and the outer surface of the housing recess is an outer layer (heat resistant resin layer) 92 (see FIG. 15).

In Fig. 15, reference numeral 39 denotes a heat seal portion in which a peripheral portion of the planar outer casing 28 and a flange portion (sealing portion for sealing) of the outer casing 1 are joined (fused). Further, in the power storage device 30, the end portion before the tab of the main body portion 31 of the power storage device is connected to the outside of the exterior member 29, but the illustration is omitted.

The power storage device main body portion 31 is not particularly limited, and examples thereof include a battery main body portion, a capacitor main body portion, and an electric double layer capacitor main body portion.

In the above embodiment, the exterior member 29 is formed of the outer casing 1 and the planar outer casing 28 (see FIG. 15). However, the exterior member 29 is not particularly limited to such a configuration. For example, the exterior member 29 is also A pair of outer casings 1 can be formed.

[Examples]

Next, specific embodiments of the present invention will be described, but the present invention is not limited to the embodiments.

<Example 1>

The twist forming mold 40 shown in Fig. 1 is used, and the twist forming mold 40 is provided with a punch 43 having the structure shown in Figs. 2 to 4, and the outer casing is manufactured by the method of manufacturing the outer casing. The material 91 is subjected to stretch forming (see Fig. 5) to manufacture the outer casing 1 for an electrical storage device shown in Fig. 6. At this time, the forming was performed, and the forming depth was gradually increased (increased) from 3.0 mm to 0.5 mm, and the outer casing was obtained for each forming depth. Further, when the forming depth is gradually increased by 0.5 mm, when the pinhole and the crack of the outer casing are confirmed, the above-mentioned stretching is completed.

The dimensions of the hard mold and the press plate to be used are a rectangle having a long side of 120 mm × a short side of 80 mm, individual holes, a long side straight line system of 50.4 mm, and a short side straight line part of 29.8 mm. Further, in the punching machine 43 to be used, the radius of curvature (S ₁ ) of the vertical section of the ridge portion 45 is 2.0 mm, and the radius of curvature (S ₂ ) of the vertical section of the corner apex portion 46 is 4.0 mm, and the transition wall portion is The length (M) of the horizontal direction of 47 is 1.0 mm, and the radius of curvature (S ₃ ) of the horizontal section of the corner wall portion 44 is 2.5 mm (see Figs. 2 to 4).

In addition, the material sheet (exterior material) 91 used is a surface of one side of an aluminum foil (aluminum foil of A8021 prescribed by JIS H4160-2006) having a thickness of 30 μm via a urethane-based adhesive (the outer side is followed by The agent 95 is bonded to a two-axis stretch nylon film 92 having a thickness of 25 μm, and the other side of the aluminum foil 94 is provided with a two-liquid-hardened maleic acid-modified polypropylene adhesive (inner adhesive) 96 and a thickness of 40 μm. The non-stretched polypropylene film 93 is bonded to the formed laminate (see Fig. 14). The material plate 91 has the same dimensions as the hard mold and the pressure plate, and has a rectangular shape with a long side of 120 mm and a short side of 80 mm.

In the outer casing 1 for a power storage device, the radius of curvature (R ₁ ) of the vertical section of the ridge line portion 5 of the housing case 2 is 2.0 mm, and the radius of curvature (R ₂ ) of the vertical section of the corner apex portion 6 is 4 .0 mm, the length (L) of the transfer wall portion 7 in the horizontal direction is 1.0 mm (see Figs. 8 to 10).

<Example 2>

The curvature radius S ₂ of the vertical section of the corner apex portion 46 is set to 4.1 mm, except that the radius of curvature S ₁ of the vertical section of the ridge portion 45 of the punch 43 is set to 4.0 mm, and the horizontal direction of the transfer wall portion 47 is set. The outer casing 1 for the electrical storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that the length M was set to 1.0 mm. In the outer casing 1 for a power storage device, the radius of curvature R ₁ of the vertical section of the ridge portion 5 of the housing case 2 is 4.0 mm, and the radius of curvature R ₂ of the vertical section of the corner apex portion 6 is 4.1 mm. The length L of the wall portion 7 in the horizontal direction is 1.0 mm (see Figs. 8 to 10).

<Example 3>

The outer casing 1 for the electrical storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that S _{1 was} set to 0.5 mm, S _{2 was} set to 4.0 mm, and M was set to 1.0 mm. In the outer casing 1 for a power storage device, the R ₁ of the housing case 2 is 0.5 mm, R ₂ is 4.0 mm, and L is 1.0 mm (see FIGS. 8 to 10 ).

<Example 4>

The outer casing 1 for the electricity storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that S _{1 was} set to 2.0 mm in the press, and S _{2 was} set to 2.1 mm and M was set to 1.0 mm. In the outer casing 1 for a power storage device, the R ₁ of the casing 2 is 2.0 mm, R ₂ is 2.1 mm, and L is 1.0 mm (see FIGS. 8 to 10 ).

<Example 5>

The outer casing 1 for the electricity storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that S _{1 was} set to 2.0 mm in the press, S _{2 was} set to 6.0 mm, and M was set to 1.0 mm. In the outer casing 1 for a power storage device, the R ₁ of the casing 2 is 2.0 mm, R ₂ is 6.0 mm, and L is 1.0 mm (see FIGS. 8 to 10 ).

<Example 6>

The outer casing 1 for the electrical storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that S _{1 was} set to 2.0 mm in the punching machine, S _{2 was} set to 4.0 mm, and M was set to 0 mm. In the outer casing 1 for the electric storage device, the R ₁ of the casing 2 is 2.0 mm, R ₂ is 4.0 mm, and L is 0 mm (see FIGS. 8 to 10 ).

<Example 7>

The outer casing 1 for the electricity storage device shown in Fig. 6 was produced in the same manner as in the first embodiment except that S _{1 was} set to 2.0 mm in the press, S _{2 was} set to 4.0 mm, and M was set to 6.0 mm. In the outer casing 1 for a power storage device, the R ₁ of the housing 2 is 2.0 mm, R ₂ is 4.0 mm, and L is 6.0 mm (see FIGS. 8 to 10 ).

<Comparative Example 1>

An outer casing for a storage battery device was produced in the same manner as in the first embodiment except that S _{1 was} set to 2.0 mm in the press, S _{2 was} set to 2.0 mm, and M was set to 0 mm. In the outer casing for the electric storage device, the R ₁ of the housing case was 2.0 mm, the R ₂ was 2.0 mm, and the L system was 0 mm.

<Comparative Example 2>

An outer casing for a storage battery device was produced in the same manner as in the first embodiment except that S _{1 was} set to 4.0 mm in the press, S _{2 was} set to 2.0 mm, and M was set to 1.0 mm. In the outer casing for the electric storage device, the R ₁ of the housing case was 4.0 mm, the R ₂ was 2.0 mm, and the L system was 1.0 mm.

The outer casing for each electrical storage device obtained as described above was evaluated for formability based on the following evaluation method. The results are shown in Table 1.

<Formability Evaluation Method>

Investigate the presence of wrinkles, pinholes, and cracks in each of the outer casings (the outer casings formed by the forming of the 0.5 mm unit), and investigate such wrinkles, pinholes, and cracks. The "maximum forming depth (mm)" was evaluated based on the following criteria. Moreover, the presence or absence of pinholes or cracks is investigated by light transmission in a dark room.

(judgment basis)

○"...The maximum forming depth of wrinkles, pinholes and cracks does not occur is 6.0mm or more.

"△"... The maximum forming depth of wrinkles, pinholes and ruptures is 4.5 mm or more and less than 6.0 mm.

“×”... The maximum forming depth of wrinkles, pinholes and cracks that did not occur was less than 4.5 mm.

As is clear from Table 1, the outer casing for the electrical storage device according to the first to seventh embodiments of the present invention obtained by the production method of the present invention does not cause wrinkles or pinholes even when the molding is deep. And rupture (crack) and excellent formability. According to the present invention, it is possible to provide an exterior casing for a power storage device including a housing portion having a deep depth.

On the other hand, in Comparative Examples 1 and 2 which deviated from the predetermined range of the present invention, wrinkles, pinholes, and cracks occurred when molding was performed at a deep molding depth.

[Industry Utilization]

An outer casing for an electrical storage device obtained by the outer casing for an electrical storage device of the present invention and the method for producing the present invention, as a specific example, for example,

‧Electric storage devices such as lithium batteries (lithium ion batteries, lithium polymer batteries, etc.)

‧Lithium ion capacitor

‧Electric double layer capacitor

‧All solid state battery

The various power storage devices are used in addition to the outer casing.

The present application claims priority to Japanese Patent Application No. 2016-226436, the entire disclosure of which is incorporated herein by reference.

The terms and descriptions used herein are for describing embodiments of the invention, but the invention is not limited thereto. Various modifications within the scope of the invention should be construed as being acceptable.

Claims (10)

An outer casing for a power storage device, comprising: a housing case having a slightly polygonal column shape with a bottom surface open; and a power storage device having a flange portion extending outward from a peripheral edge of the opening of the bottom surface of the housing case The outer casing is characterized in that the adjacent side walls of the accommodating casing are connected by the corner wall portions disposed on the curved surfaces of each other; the sides constituting the top wall of the accommodating casing are individually The edge of the top wall and the ridge line of the curved surface are connected; the corner edges of the top wall are connected by the upper edge of the individual corner wall portion and the corner apex portion having the curved surface; the radius of curvature of the ridge portion is "R ₁ ", when the radius of curvature of the vertical section of the apex portion of the corner is "R ₂ ", the relationship of R ₁ &lt; R ₂ is satisfied.  The outer casing for a power storage device according to claim 1, wherein the slightly polygonal column shape is a substantially rectangular parallelepiped shape.    The outer casing for a power storage device according to the first or second aspect of the invention, wherein the edge of the ridge portion in the horizontal direction and the edge of the corner apex facing the edge are transferred Connected to the wall.    The outer casing for a power storage device according to the third aspect of the invention, wherein at least a part of a boundary ridge line between the transfer wall portion and the top wall is curved outward in a plan view.    The outer casing for a power storage device according to the third aspect of the invention, wherein the length of the transfer wall portion in the horizontal direction is more than 0 mm and not more than 5 mm.    The outer casing for a power storage device according to claim 1 or 2, wherein the storage casing and the flange portion are formed of a laminate, and the laminate includes: a metal foil a sealing layer in which a layer and a surface on one side of the metal foil layer are laminated.    A power storage device, comprising: a power storage device main body portion, and an outer casing outer casing member for a power storage device according to any one of claims 1 to 6, wherein the power storage device main body portion is The exterior member is externally attached.   A method for producing an outer casing for a power storage device, which is a method for producing an outer casing for a power storage device by using a tool for forming a strand to form a casing for a power storage device, wherein the die for forming a strand is provided with a punch The material plate is inserted into the three-dimensionally shaped shape of a slightly polygonal column; the hard mold has a hole in a shape of a slightly polygonal column that is inserted into the material plate of the punching machine; and the pressure plate is inserted into the hole of the punching machine; the outer casing of the power storage device is The manufacturing method is characterized in that: a sandwiching step of sandwiching the material sheet between the sandwich layer around the hole of the hard mold and the periphery of the hole of the pressure plate; forming step by using the punching machine The hole of the pressure plate is inserted into the hole of the hard mold, and the material plate is stretched to obtain an outer casing for the power storage device; the punch is adjacent to the side wall through the curved surface disposed therebetween The corner walls are connected; the sides of the top wall are connected by the upper side of the side wall and the ridge line of the curved surface; the corner edges of the top wall are On the edge of the other corner wall and includes a curved corner portion are connected to the vertex of the press; and the method of manufacturing a power storage device using the outer shell of the system: the radius of curvature of the ridge line portion is "S _1", the corner point When the radius of curvature of the vertical section of the section is "S ₂ ", the punch that satisfies the relationship of S ₁ <S ₂ is used.  The method for producing an outer casing for a power storage device according to claim 8, wherein the slightly polygonal column shape is a substantially rectangular parallelepiped shape.    The manufacturing method of the outer casing for a power storage device according to the eighth aspect of the invention, wherein the edge of the ridge portion in the horizontal direction and the corner apex portion facing the edge The end edges are connected by a transfer wall portion.