Electric storage device

Abstract

The present disclosure relates to a power storage device. In an element case of an energy storage element according to the present disclosure, a cylindrical body portion is formed by forming a film into a cylindrical shape, and a first opening portion and a second opening portion are formed at both ends, respectively. The first sealing body seals the first opening part. And the second sealing body seals the second opening part. The first sealing body has an outer peripheral surface that is in contact with the inner peripheral surface of the cylindrical main body part. The outer peripheral surface has a main body surface portion and a protruding portion. The main body surface portion extends parallel to a first direction in which the first opening portion and the second opening portion are arranged. The protruding portion protrudes from the main body surface portion toward the cylindrical main body portion.

Description

Technical Field

[0001] The present disclosure relates to an electric storage element. Background Art

[0002] Japanese Patent Application Laid-Open No. 2019-106372 discloses a battery having a battery case and an electrode assembly. The battery case includes a housing portion for housing the electrode assembly and a cover portion. The cover portion covers at least a portion of an open surface of the housing portion. After the electrode assembly is arranged and the electrolyte is injected, the open surface of the housing portion is closed or sealed by the cover portion. Summary of the invention

[0003] For the battery element housing disclosed in Japanese Patent Publication No. 2019-106372, it is important to suppress the decrease in sealing in order to suppress the change in the amount of water in the element housing. In addition, when the storage element is used, for example, for vehicle-mounted use, it is required to make the storage element lower and to make the size of the storage element larger in one direction in the lateral direction in order to suppress the decrease in energy density. However, in the previous storage element, it is difficult to manufacture an element housing with a further longer size in the above-mentioned one direction. Therefore, there is a restriction on the size in the above-mentioned one direction.

[0004] The present disclosure has been made in view of the above-mentioned problems. An object of the present disclosure is to provide an electric storage element that can improve the dimensional freedom in one direction of an element case and suppress a decrease in the sealing performance of the element case.

[0005] The storage element based on the present disclosure comprises an electrode body and an element shell. The element shell accommodates the electrode body. The element shell has a cylindrical main body, a first sealing body and a second sealing body. The cylindrical main body is formed by forming a film into a cylindrical shape, and a first opening and a second opening are formed at both ends respectively. The first sealing body seals the first opening. The second sealing body seals the second opening. The first sealing body has an outer peripheral surface in contact with the inner peripheral surface of the cylindrical main body. The outer peripheral surface has a main body surface portion and a protrusion. The main body surface portion extends parallel to a first direction in which the first opening portion and the second opening portion are arranged. The protrusion protrudes from the main body surface portion toward the cylindrical main body portion.

[0006] According to the above structure, the cylindrical main body of the element housing is formed by a film. Therefore, the dimensional freedom of the element housing in the first direction can be improved. Moreover, even when the cylindrical main body is formed by a film, the inner peripheral surface of the cylindrical main body and the outer peripheral surface of the first sealing body form a labyrinth structure through the main body surface portion and the protruding portion. Therefore, even when the cylindrical main body of the element housing is formed by a film, the decrease in the sealing performance of the element housing can be suppressed.

[0007] According to the present disclosure, it is possible to improve the degree of freedom of the dimension of the element case in one direction and suppress a decrease in the sealing performance of the element case. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Features, advantages and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like numerals represent like elements, and in which:

[0009] Figure 1 is a perspective view showing an electric storage element according to one embodiment;

[0010] Figure 2 is an exploded perspective view of an electric storage element according to an embodiment;

[0011] Figure 3 It is along Figure 1 A cross-sectional view taken along line III-III as shown;

[0012] Figure 4 It is along Figure 1 A cross-sectional view of line IV-IV shown;

[0013] Figure 5 Yes Figure 3 A partial cross-sectional view showing an enlarged area V;

[0014] Figure 6 This is a perspective view schematically showing a state in the middle of molding an element case in an electric storage element according to an embodiment. DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure are described with reference to the accompanying drawings. It should be noted that, in the drawings referred to below, the same or corresponding components are denoted by the same reference numerals.

[0016] Figure 1 It is a perspective view showing an electric storage element according to an embodiment. Figure 2 It is an exploded perspective view of an electric storage element according to an embodiment. Figure 3 It is along Figure 1 The cross-sectional view of line III-III is shown in FIG. Figure 1~Figure 3 As shown, the electric storage device 10 according to one embodiment includes an electrode body 100 , a device case 200 , a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.

[0017] Figure 4 It is along Figure 1 The cross-sectional view of the line IV-IV is shown in FIG. Figure 4 In the figure, for convenience, the element case 200 of the storage element 10 is omitted, and only the electrode body 100 is shown. Figure 4 The electrode body 100 will be described in detail.

[0018] like Figure 4 As shown, the electrode body 100 includes a plurality of positive electrodes 110 and a plurality of negative electrodes 120 and a separator 130. The plurality of positive electrodes 110 and the plurality of negative electrodes 120 are arranged alternately in the thickness direction (second direction D2) while being insulated by the separator 130.

[0019] Each negative electrode 120 is formed into a rectangular shape with the width direction (first direction D1) as the long side and the height direction (third direction D3) as the short side. The second direction D2 is a direction perpendicular to the first direction D1. The third direction D3 is a direction perpendicular to both the first direction D1 and the second direction D2. Each negative electrode 120 includes a negative electrode collector foil 122 and a negative electrode active material layer 124 provided on both sides of the negative electrode collector foil 122. The negative electrode collector foil 122 includes a negative electrode tab 122n (see Figure 3 ). The negative electrode tab 122n protrudes toward one side in the first direction D1.

[0020] Each positive electrode 110 is formed into a rectangular shape with the first direction D1 as the long side and the third direction D3 as the short side. Each positive electrode 110 includes a positive electrode collector foil 112 and a positive electrode active material layer 114 provided on both sides of the positive electrode collector foil 112 in the second direction D2. The positive electrode collector foil 112 includes a positive electrode tab 112p (see Figure 3 ). The positive electrode tab 112p protrudes toward the other side of the first direction D1.

[0021] The separator 130 insulates the positive electrode 110 from the negative electrode 120. The separator 130 is made of an insulating material and has minute gaps that allow ions to pass through. The separator 130 is formed in a zigzag shape.

[0022] The separator 130 has a rectangular shape before being formed into a zigzag shape. The separator 130 is arranged between the positive electrode 110 and the negative electrode 120 while being formed into a zigzag shape. The separator 130 has a plurality of intervening portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0023] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120 adjacent to each other in the second direction D2. In other words, each intervening portion 132a has a function of insulating the positive electrode 110 from the negative electrode 120. Each intervening portion 132a is composed of a rectangular region.

[0024] Each first folded portion 132b connects the ends of the interposed portions 132a adjacent to each other in the second direction D2 in a manner that the positive electrode 110 is located in between. The first folded portion 132b is disposed on one side (upper side) of the positive electrode 110 in the third direction D3.

[0025] Each second folded portion 132c connects the other ends of the interposed portions 132a adjacent to each other in the second direction D2 so that the negative electrode 120 is located in between. The second folded portion 132c is disposed on the other side (lower side) of the negative electrode 120 in the third direction D3.

[0026] The outermost covering portion 132d covers the first return portions 132b and the second return portions 132c collectively. In more detail, the outermost covering portion 132d covers all the positive electrodes 110, all the negative electrodes 120, all the interposing portions 132a, all the first return portions 132b and all the second return portions 132c collectively while winding around a central axis parallel to the first direction D1. The terminal 132e of the outermost covering portion 132d is set to a range that does not overlap with the positive electrode active material layer 114 and the negative electrode active material layer 124 in the second direction D2. In the present embodiment, the terminal 132e of the outermost covering portion 132d is arranged below each positive electrode 110 and each negative electrode 120. It should be noted that the peripheral surface and bottom surface of the plurality of positive electrodes 110, the plurality of negative electrodes 120 and the separator 130 may also be covered with an insulating film (not shown).

[0027] The element case 200 accommodates the electrode body 100. The element case 200 has a substantially rectangular parallelepiped shape. The element case 200 is configured such that the dimension in the first direction D1 is longer than the dimension in the third direction D3 and the dimension in the second direction D2. In addition, the element case 200 is configured such that the dimension in the third direction D3 is longer than the dimension in the second direction D2.

[0028] The element case 200 accommodates the electrode body 100 and an electrolyte solution (not shown) therein. The element case 200 includes a cylindrical main body 210 , a first sealing body 510 , and a second sealing body 610 .

[0029] A first opening 218 and a second opening 219 are formed at both ends of the tubular body 210 in the first direction D1. The first opening 218 is provided on one side of the first direction D1. The second opening 219 is provided on the other side of the first direction D1. The tubular body 210 is formed by forming the film F into a tubular shape. The specific forming method of the tubular body 210 will be described later.

[0030] The cylindrical body portion 210 includes a bottom portion 211 , a first side portion 212 , a second side portion 213 , a top portion 214 , and a strip-shaped portion 215 .

[0031] The bottom surface portion 211 is located on one side in the third direction D3 and has a rectangular outer shape when viewed from the third direction D3.

[0032] The first side surface portion 212 stands along the third direction D3 from one end of the bottom surface portion 211 in the second direction D2. The second side surface portion 213 stands along the third direction D3 from the other end of the bottom surface portion 211 in the second direction D2. The first side surface portion 212 and the second side surface portion 213 have a rectangular shape when viewed from the second direction D2.

[0033] The top face portion 214 is located on the other side of the third direction D3. The top face portion 214 has a rectangular shape when viewed from the third direction D3. The top face portion 214 connects the upper ends of the first side face portion 212 and the second side face portion 213 to each other. In the present embodiment, the top face portion 214 extends from the first side face portion 212. The top face portion 214 is connected to the second side face portion 213 via a strip portion 215.

[0034] The strip-shaped portion 215 is formed by joining a first side end portion FE1 and a second side end portion FE2 located at both ends of the film F to each other.

[0035] The strip portion 215 extends along the first direction D1. The strip portion 215 extends outward from the element housing 200. As described above, in the present embodiment, the strip portion 215 connects the top surface portion 214 and the second side surface portion 213. However, the position of the strip portion 215 is not particularly limited. The strip portion 215 may connect the top surface portion 214 and the first side surface portion 212, may connect the bottom surface portion 211 and the first side surface portion 212, or may connect the bottom surface portion 211 and the second side surface portion 213.

[0036] The first opening 218 is formed by the bottom surface 211, the first side surface 212, the second side surface 213, and one end of the top surface 214. The second opening 219 is formed by the other ends thereof.

[0037] The first sealing member 510 seals the first opening 218. The first sealing member 510 has a (first) outer peripheral surface 511S in contact with the inner peripheral surface 210S of the cylindrical body 210. In the present embodiment, the entire first sealing member 510 is located on the inner peripheral surface 210S side of the cylindrical body 210.

[0038] Figure 5 Yes Figure 3 The area V is enlarged to show a partial cross-sectional view. Figure 2 , Figure 3 and Figure 5 As shown, the outer peripheral surface 511S has a (first) main body surface portion 511Sa and a (first) protruding portion 511Sb.

[0039] The main body surface portion 511Sa extends in parallel with the first direction D1 in which the first opening 218 and the second opening 219 are arranged (see Figure 5The protrusion 511Sb protrudes from the main body surface portion 511Sa toward the cylindrical main body portion 210. The protrusion 511Sb extends in an annular shape along the circumferential direction of the inner peripheral surface 210S of the cylindrical main body portion 210 (see Figure 2 ).

[0040] The first sealing member 510 includes a first plate-shaped portion 511 and a first extending portion 512. Specifically, the first plate-shaped portion 511 includes the outer peripheral surface 511S described above.

[0041] The first plate-like portion 511 has a flat plate shape. The first plate-like portion 511 extends parallel to an imaginary plane orthogonal to the first direction D1 in which the first opening 218 and the second opening 219 are arranged. That is, the first plate-like portion 511 is located on the inner peripheral surface 210S side of the cylindrical body 210. The first plate-like portion 511 is made of a metal such as aluminum. A negative electrode member 520 is provided on the first plate-like portion 511.

[0042] The first plate-shaped portion 511 is provided with a pressure relief valve 515. The pressure relief valve 515 is provided so as to rupture when the internal pressure of the element case 200 becomes equal to or higher than a predetermined pressure. When the pressure relief valve 515 ruptures, the gas in the element case 200 is discharged to the outside of the element case 200. Therefore, the internal pressure in the element case 200 is reduced.

[0043] The first extension portion 512 extends from the first plate-shaped portion 511 in the first direction D1. The first extension portion 512 is disposed on the inner peripheral surface 210S side of the cylindrical body portion 210 (see Figure 3 The first extension portion 512 extends along the inner circumferential surface 210S of the cylindrical body portion 210 and has a cylindrical shape (see Figure 2 Specifically, the first extension portion 512 has a rectangular cylindrical shape. The first extension portion 512 is joined to the inner peripheral surface 210S of the cylindrical main body portion 210.

[0044] The first extension portion 512 includes an inner layer portion 512a and an outer layer portion 512b. The inner layer portion 512a is formed integrally with the first plate-shaped portion 511. That is, the first plate-shaped portion 511 is made of a metal such as aluminum. The outer layer portion 512b is disposed between the inner layer portion 512a and the cylindrical main body portion 210. The outer layer portion 512b is made of resin. The outer layer portion 512b is joined to the inner circumferential surface 210S of the cylindrical main body portion 210 by thermal fusion.

[0045] The negative electrode member 520 is provided on the outer surface of the first plate-shaped portion 511 . The negative electrode member 520 functions as a negative electrode terminal. The negative electrode member 520 includes a negative electrode terminal plate 521 and an insulating plate 522 .

[0046] The negative terminal plate 521 is formed in a substantially rectangular parallelepiped shape. The negative terminal plate 521 is held by an insulating plate 522. The insulating plate 522 is fixed to the outer surface of the first plate-shaped portion 511. The insulating plate 522 insulates the first plate-shaped portion 511 from the negative terminal plate 521. Through holes for inserting a negative electrode connecting pin 533 described later are provided in the negative terminal plate 521 and the insulating plate 522, respectively.

[0047] The second sealing member 610 seals the second opening 219. The second sealing member 610 has a second outer peripheral surface 611S in contact with the inner peripheral surface 210S of the cylindrical body 210. In the present embodiment, the entire second sealing member 610 is located on the inner peripheral surface 210S side of the cylindrical body 210.

[0048] The second outer peripheral surface 611S has a second main body surface portion 611Sa and a second protruding portion 611Sb.

[0049] The second main body surface portion 611Sa extends parallel to the first direction D1. The second protrusion 611Sb protrudes from the second main body surface portion 611Sa toward the cylindrical main body portion 210. The second protrusion 611Sb extends annularly along the circumferential direction of the inner peripheral surface 210S of the cylindrical main body portion 210.

[0050] The second sealing member 610 includes a second plate-shaped portion 611 and a second extending portion 612. Specifically, the second plate-shaped portion 611 includes the second outer peripheral surface 611S described above.

[0051] The second plate-like portion 611 has a flat plate shape. The second plate-like portion 611 extends parallel to an imaginary plane orthogonal to the first direction D1. That is, the second plate-like portion 611 extends parallel to both the second direction D2 and the third direction D3. The second plate-like portion 611 is located on the inner circumferential surface 210S side of the cylindrical main body 210. The second plate-like portion 611 is made of a metal such as aluminum. A positive electrode component 620 is provided on the second plate-like portion 611.

[0052] The second plate-shaped portion 611 is provided with a pressure relief valve 615. The pressure relief valve 615 is provided so as to rupture when the internal pressure of the element case 200 becomes equal to or higher than a predetermined pressure. When the pressure relief valve 615 ruptures, the gas in the element case 200 is discharged to the outside of the element case 200, so that the internal pressure in the element case 200 decreases.

[0053] The second extension portion 612 extends from the second plate-shaped portion 611 in the first direction D1. The second extension portion 612 is disposed on the inner peripheral surface 210S side of the cylindrical body portion 210 (see Figure 3 The second extension portion 612 extends along the inner circumferential surface 210S of the cylindrical main body 210 and has a cylindrical shape (see Figure 2Specifically, the second extension portion 612 has a rectangular cylindrical shape. The second extension portion 612 is joined to the inner peripheral surface 210S of the cylindrical main body portion 210.

[0054] The second extension portion 612 includes an inner layer portion 612a and an outer layer portion 612b. The inner layer portion 612a is formed integrally with the second plate-shaped portion 611. That is, the second plate-shaped portion 611 is made of a metal such as aluminum. The outer layer portion 612b is disposed between the inner layer portion 612a and the cylindrical main body portion 210. The outer layer portion 612b is made of resin. The outer layer portion 612b is joined to the inner circumferential surface 210S of the cylindrical main body portion 210 by thermal fusion.

[0055] The positive electrode member 620 is provided on the outer surface of the second plate-shaped portion 611 . The positive electrode member 620 functions as a positive electrode terminal. The positive electrode member 620 includes a positive electrode terminal plate 621 and a terminal block 622 .

[0056] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of metal such as aluminum.

[0057] The terminal block 622 is formed in a rectangular parallelepiped shape. The terminal block 622 is made of a metal (iron, etc.) different from the metal constituting the positive terminal plate 621. The terminal block 622 is fixed to the outer surface of the second plate-shaped portion 611 by welding or the like. The positive terminal plate 621 is fixed to the terminal block 622 by welding or the like. The second plate-shaped portion 611 is electrically connected to the positive terminal plate 621 via the terminal block 622, and is charged to the same polarity as the positive terminal plate 621. A through hole for inserting the positive electrode connecting pin 633 described later is formed in the positive terminal plate 621 and the terminal block 622, respectively.

[0058] It should be noted that an insulating plate may be disposed between the positive electrode member 620 and the second plate-shaped portion 611 to electrically insulate the positive electrode member 620 from the second sealing body 610. In this case, the insulating plate may be disposed instead of the terminal block 622 or between the terminal block 622 and the second plate-shaped portion 611.

[0059] The energy storage device 10 further includes a negative electrode connecting member 530 , a negative electrode side insulating member 550 , and an insulator 560 on the negative electrode member 520 side.

[0060] The negative electrode connecting member 530 connects the negative electrode current collecting portion 120N and the negative electrode terminal plate 521. The negative electrode current collecting portion 120N is formed by bundling a plurality of negative electrode tabs 122n described later in the electrode body 100. The negative electrode connecting member 530 includes a negative electrode side first current collector 531, a negative electrode side second current collector 532, and a negative electrode connecting pin 533.

[0061] The negative electrode side first current collector 531 is composed of a thin plate-shaped conductive member and is connected to the negative electrode current collecting portion 120N by laser welding, ultrasonic welding or the like.

[0062] The second negative electrode side current collector 532 is composed of a thin plate-shaped conductive member. The second negative electrode side current collector 532 is connected to the first negative electrode side current collector 531 by laser welding or ultrasonic welding. The second negative electrode side current collector 532 has a holding portion 532a for holding the negative electrode connecting pin 533. The holding portion 532a has a flat plate shape. A through hole is provided in the holding portion 532a for inserting the base end of the negative electrode connecting pin 533.

[0063] The negative electrode connecting pin 533 connects the negative electrode side second current collector 532 and the negative electrode terminal plate 521. The negative electrode connecting pin 533 includes a cylindrical portion. The top end of the cylindrical portion penetrates the first sealing body 510, the insulating plate 522 and the negative electrode terminal plate 521 and is riveted to the negative electrode terminal plate 521.

[0064] The negative electrode side insulating member 550 is disposed between the first extension portion 512 and the electrode body 100. The negative electrode side insulating member 550 is provided with a slit 552 through which the negative electrode current collecting portion 120N is inserted.

[0065] The first extension 512 and the negative electrode side insulating member 550 are assembled to form a receiving space between the first plate-shaped portion 511 and the negative electrode side insulating member 550. The negative electrode current collecting portion 120N inserted through the slit 552, the negative electrode side first current collector 531, and the negative electrode side second current collector 532 are arranged in the receiving space.

[0066] The insulator 560 has a shape covering the cylindrical portion of the negative electrode connecting pin 533. The insulator 560 insulates the negative electrode connecting pin 533 from the element case 200 (more specifically, the first plate-shaped portion 511).

[0067] The negative electrode member 520 , the first sealing body 510 , the negative electrode connecting member 530 , the negative electrode side insulating member 550 , and the insulator 560 are incorporated to form the first cap assembly 50 .

[0068] The first cap assembly 50 is fixed to the cylindrical body portion 210 by attaching the first sealing body 510 to the first opening portion 218 in a state where the negative electrode current collecting portion 120N and the negative electrode connecting member 530 are fixed by welding or the like.

[0069] The energy storage device 10 further includes a positive electrode connecting member 630 , a positive electrode side insulating member 650 , and an insulator 660 on the positive electrode member 620 side.

[0070] The positive electrode connecting member 630 connects the positive electrode current collecting portion 110P and the positive electrode terminal plate 621. The positive electrode current collecting portion 110P is formed by bundling a plurality of positive electrode tabs 112p described later in the electrode body 100. The positive electrode connecting member 630 includes a positive electrode side first current collector 631, a positive electrode side second current collector 632, and a positive electrode connecting pin 633.

[0071] The positive electrode side first current collector 631 is composed of a thin plate-shaped conductive member and is connected to the positive electrode current collecting portion 110P by laser welding, ultrasonic welding or the like.

[0072] The second current collector 632 on the positive electrode side is composed of a thin plate-shaped conductive member. The second current collector 632 on the positive electrode side is connected to the first current collector 631 on the positive electrode side by laser welding or ultrasonic welding. The second current collector 632 on the positive electrode side has a holding portion 632a for holding the positive electrode connecting pin 633. The holding portion 632a has a flat plate shape. A through hole is provided in the holding portion 632a for inserting the base end of the positive electrode connecting pin 633.

[0073] The positive electrode connecting pin 633 connects the positive electrode side second current collector 632 and the positive electrode terminal plate 621. The positive electrode connecting pin 633 includes a cylindrical portion. The top end of the cylindrical portion penetrates the second sealing body 610, the terminal block 622 and the positive electrode terminal plate 621 and is riveted to the positive electrode terminal plate 621.

[0074] The positive electrode side insulating member 650 is disposed between the second extension portion 612 and the electrode body 100. The positive electrode side insulating member 650 is provided with a slit 652 through which the positive electrode current collecting portion 110P is inserted.

[0075] The second extension 612 and the positive electrode side insulating member 650 are assembled to form a receiving space between the second plate-shaped portion 611 and the positive electrode side insulating member 650. The positive electrode current collecting portion 110P inserted through the slit 552, the positive electrode side first collector 631, and the positive electrode side second collector 632 are arranged in the receiving space.

[0076] The insulator 660 has a shape covering the cylindrical portion of the positive electrode connecting pin 633. The insulator 660 insulates the positive electrode connecting pin 633 from the element case 200 (more specifically, the second plate-shaped portion 611).

[0077] The positive electrode component 620 , the second sealing body 610 , the positive electrode connecting member 630 , the positive electrode side insulating member 650 , and the insulator 660 are incorporated to form the second cap assembly 60 .

[0078] The second cap assembly 60 is fixed to the cylindrical body portion 210 by attaching the second sealing body 610 to the second opening portion 219 in a state where the positive electrode current collecting portion 110P and the positive electrode connecting member 630 are fixed by welding or the like.

[0079] Next, a method for molding the cylindrical body portion 210 using the film F will be described. Figure 6 1 is a perspective view schematically showing a state in which an element case is being molded in an electric storage element according to an embodiment. Figure 6 In FIG. 1 , the parts of the film F are denoted by the same reference numerals as the corresponding parts of the tubular body 210 .

[0080] In this embodiment, the forming method of the cylindrical body 210 includes three welding steps. Figure 1~Figure 3 and Figure 6 As shown, in the first welding step, the film F is folded and the portions of the film F corresponding to the bottom surface portion 211, the first side surface portion 212, and the second side surface portion 213 are heat-welded to the first extension portion 512 and the second extension portion 612. Figure 6 At the same time, the above-mentioned parts of the film F may be bonded to the (first) outer peripheral surface 511S and the second outer peripheral surface 611S using an adhesive or the like.

[0081] Next, in the second welding step, the portion of the film F corresponding to the top surface portion 214 is thermally welded to the first extension portion 512 and the second extension portion 612. At the same time, the portion of the film F corresponding to the top surface portion 214 may be bonded to the (first) outer peripheral surface 511S and the second outer peripheral surface 611S using an adhesive or the like.

[0082] Finally, in the third welding step, the first side end FE1 and the second side end FE2 are heat-welded to each other, thereby forming the cylindrical body 210, and the cylindrical body 210 is sealed by the first sealing body 510 and the second sealing body 610. The order of the second welding step and the third welding step is not particularly limited.

[0083] It should be noted that after the first welding step and before the second welding step and the third welding step, an electrolyte solution is injected (see Figure 6 ). Specifically, the electrolyte is injected into the space formed by the film F, the first sealing body 510, and the second sealing body 610 through the injection tube P. In this way, by forming the cylindrical body 210 using the film F, even if the cylindrical body 210 is relatively long in the first direction D1, the electrolyte can be easily injected throughout the entire first direction D1.

[0084] Next, the film constituting the cylindrical body portion 210 will be described. Figure 5As shown, the film F in this embodiment is a so-called laminate film. The thickness of the film F is, for example, 70 μm or more and 220 μm or less. The film F includes a resin layer L1, a metal layer L2, and a second resin layer L3.

[0085] The resin layer L1 constitutes the inner circumferential surface 210S of the cylindrical body 210. In the present embodiment, the resin layer L1 has a (first) hole portion H1 and a second hole portion H2. The hole portion H1 is engaged with the protrusion 511Sb. The second hole portion H2 is engaged with the second protrusion 611Sb. The hole portion H1 and the second hole portion H2 penetrate the resin layer L1. The hole portion H1 extends in an annular shape along the protrusion 511Sb. The second hole portion H2 extends in an annular shape along the second protrusion 611Sb.

[0086] It should be noted that the hole H1 and the second hole H2 may not be provided. When the resin layer L1 is not provided with the hole H1, the film F (cylindrical body 210) may be bent along the protrusion 511Sb. When the resin layer L1 is not provided with the second hole H2, the film F (cylindrical body 210) may be bent along the second protrusion 611Sb.

[0087] In addition, the outer layer portion 512b made of resin in the first extension portion 512 is thermally fused to the resin layer L1. Similarly, the outer layer portion 612b made of resin in the second extension portion 612 is thermally fused to the resin layer L1.

[0088] Examples of the material of the resin layer L1 include olefin resins such as polypropylene (PP) and polyethylene (PE). The thickness of the resin layer L1 is, for example, 40 μm to 100 μm. The resin layer L1 may include a plurality of resin films made of the above-mentioned materials.

[0089] The metal layer L2 is laminated on the resin layer L1. This can reduce the moisture permeability of the film F. Examples of the material of the metal layer L2 include aluminum, aluminum alloys, and stainless steel. The thickness of the metal layer L2 is, for example, 30 μm or more and 60 μm or less.

[0090] The second resin layer L3 is stacked on the metal layer L2 on the side opposite to the resin layer L1 when viewed from the metal layer L2. As the material of the second resin layer L3, for example, polyethylene terephthalate (PET) or nylon can be cited. The thickness of the resin layer is, for example, not less than 20 μm and not more than 60 μm. The second resin layer L3 may also include a plurality of resin films composed of the above-mentioned materials.

[0091] As described above, the energy storage element 10 according to one embodiment of the present disclosure includes an electrode body 100 and an element case 200. The element case 200 accommodates the electrode body 100. The element case 200 includes a cylindrical main body 210, a first sealing body 510, and a second sealing body 610. The cylindrical main body 210 is formed by forming a film F into a cylindrical shape, and a first opening 218 and a second opening 219 are formed at both ends, respectively. The first sealing body 510 closes the first opening 218. The second sealing body 610 closes the second opening 219. The first sealing body 510 has an outer peripheral surface 511S in contact with the inner peripheral surface 210S of the cylindrical main body 210. The outer peripheral surface 511S has a main body surface portion 511Sa and a protruding portion 511Sb. The main body surface portion 511Sa extends parallel to the first direction D1 in which the first opening 218 and the second opening 219 are arranged. The protrusion 511Sb protrudes from the main body surface portion 511Sa toward the cylindrical main body portion 210 .

[0092] According to the above structure, since the cylindrical body 210 of the element case 200 is formed by the film F, the dimensional freedom of the element case 200 in the first direction D1 can be improved. Moreover, even when the cylindrical body 210 is formed by the film F, the inner peripheral surface 210S and the outer peripheral surface 511S form a labyrinth structure through the body surface portion 511Sa and the protruding portion 511Sb. Therefore, even when the cylindrical body 210 of the element case 200 is formed by the film F, the decrease in the sealing performance of the element case 200 can be suppressed.

[0093] In the present embodiment, the film F includes a resin layer L1 constituting the inner peripheral surface 210S of the cylindrical body 210 and a metal layer L2 laminated on the resin layer L1. The resin layer L1 has a hole H1 that fits with the protrusion 511Sb.

[0094] According to the above structure, the thickness of the portion between the metal layer L2 and the protruding portion 511Sb in the resin layer L1 becomes relatively thin, thereby making it possible to further reduce the moisture permeability between the metal layer L2 and the protruding portion 511Sb.

[0095] In addition, in the present embodiment, the hole H1 penetrates the resin layer L1 , and the protrusion 511Sb contacts the metal layer L2 via the hole H1 .

[0096] According to the above-mentioned structure, the moisture permeability between the metal layer L2 and the protruding portion 511Sb can be further reduced.

[0097] In addition, in the present embodiment, the protrusion 511Sb extends annularly along the circumferential direction of the inner peripheral surface 210S of the cylindrical body 210. The hole H1 extends annularly along the protrusion 511Sb.

[0098] According to the above configuration, the main body surface portion 511Sa and the protruding portion 511Sb form a labyrinth structure in the entire circumferential direction of the inner peripheral surface 210S, thereby further suppressing a decrease in the sealing performance of the element case 200 .

[0099] It should be noted that the embodiments disclosed this time should be considered to be illustrative and non-restrictive in all aspects. The scope of the present invention is not indicated by the description of the above-mentioned embodiments but by the claims. Moreover, the scope of the present invention includes all changes within the meaning and scope equivalent to the claims.

Claims

1. A power storage element comprising: an electrode body; and An element housing, accommodating the electrode body, The element housing has: A cylindrical main body portion is formed by forming the film into a cylindrical shape, and has a first opening and a second opening formed at both ends thereof; A first sealing body, sealing the first opening; and A second sealing body seals the second opening. The first sealing body has an outer peripheral surface bonded to the inner peripheral surface of the cylindrical body. The outer peripheral surface includes a main body surface portion extending parallel to a first direction in which the first opening and the second opening are arranged, and a protrusion protruding from the main body surface portion toward the cylindrical main body portion.

2. The electric storage element according to claim 1, The film includes a resin layer constituting the inner peripheral surface of the cylindrical body and a metal layer laminated on the resin layer. The resin layer has a hole portion that fits with the protrusion.

3. The power storage element according to claim 2, The hole portion penetrates the resin layer, The protrusion is in contact with the metal layer via the hole.

4. The electric storage element according to claim 2 or 3, The protrusion extends annularly along the circumferential direction of the inner peripheral surface of the cylindrical body. The hole portion extends annularly along the protrusion.

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