Energy storage cell

Abstract

This increases the degree of dimensional freedom in one direction of the cell case and prevents a decrease in the sealing performance of the cell case. [Solution] In an energy storage cell (10) according to the present disclosure, a cylindrical main body (210) is formed by molding a film (F) into a cylindrical shape. A first sealing body (510) closes a first opening (218). A second sealing body (610) closes a second opening (219). The first sealing body (510) has a first plate-shaped portion (511) and a first extending portion (512). The first plate-shaped portion (511) extends parallel to an imaginary plane perpendicular to a first direction (D1) in which the first opening (218) and the second opening (219) are aligned. The first plate-shaped portion (511) is adjacent to the first opening (218) in the first direction (D1). The first extending portion (512) extends from the first plate-shaped portion (511) in the first direction (D1). The first extending portion (512) is disposed inside the cylindrical main body (210). The first extending portion 512 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] Patent document 1 (JP 2021-061100 A) discloses a battery cell case characterized in that the opening seal is fixed to the container lid via a resin fusion layer between the opening seal film and the container lid film, sealing the opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-061100 Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in Patent Document 1, it is important for the cell casing to suppress a decrease in sealing performance. Furthermore, when using an energy storage cell, for example, in a vehicle, it is necessary to further reduce the height of the energy storage cell and to increase the dimension in one of the lateral directions of the energy storage cell in order to suppress a decrease in energy density. However, with conventional energy storage cells, it has been difficult to manufacture a cell casing that is longer in the aforementioned one direction. This has resulted in restrictions on the dimension in the aforementioned one direction.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a storage cell that increases the dimensional freedom in one direction of the cell case and can suppress a decrease in the sealing performance of the cell case. [Means for solving the problem]

[0006] An energy storage cell according to the present disclosure includes an electrode assembly and a cell case. The cell case houses the electrode assembly. The cell case has a cylindrical main body, a first sealing body, and a second sealing body. The cylindrical main body is formed by molding a film into a cylindrical shape. A first opening and a second opening are formed at each end of the cylindrical main body. The first sealing body closes the first opening. The second sealing body closes the second opening. The first sealing body has a first plate-shaped portion and a first extending portion. The first plate-shaped portion extends parallel to an imaginary plane perpendicular to a first direction in which the first opening and the second opening are aligned. The first plate-shaped portion is adjacent to the first opening in the first direction. The first extending portion extends in the first direction from the first plate-shaped portion. The first extending portion is disposed inside the cylindrical main body. The first extending portion is joined to the inner circumferential surface of the cylindrical main body.

[0007] According to the present disclosure, the cylindrical main body portion of the cell case is formed from a film, which increases the dimensional flexibility of the cell case in the first direction. Furthermore, even when the cylindrical main body portion is formed from a film, the first sealing body has a first extension portion, which tightly bonds the first sealing body and the inner surface of the cylindrical main body portion to each other. This prevents a decrease in the sealing performance of the cell case, even when the cylindrical main body portion of the cell case is formed from a film. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to increase the degree of dimensional freedom in one direction of the cell case and to suppress a decrease in the sealing performance of the cell case. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a storage cell according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of a storage cell according to one embodiment. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. [Figure 5] FIG. 2 is a perspective view schematically showing a state in the middle of forming a cell case in the energy storage cell according to one embodiment. [Figure 6] FIG. 4 is a partial cross-sectional view showing an enlarged area VI of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or equivalent elements are designated by the same reference numerals.

[0011] Fig. 1 is a perspective view showing a storage cell according to one embodiment. Fig. 2 is an exploded perspective view of the storage cell according to one embodiment. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1. As shown in Figs. 1 to 3, the storage cell 10 according to one embodiment includes an electrode assembly 100, a cell case 200, a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.

[0012] Fig. 4 is a cross-sectional view taken along line IV-IV shown in Fig. 1. For convenience, Fig. 4 omits the cell case 200 of the energy storage cell 10 and shows only the electrode assembly 100. Details of the electrode assembly 100 will be described with reference to Fig. 4.

[0013] 4, the electrode assembly 100 includes a plurality of positive electrodes 110, a plurality of negative electrodes 120, and a separator 130. The plurality of positive electrodes 110 and the plurality of negative electrodes 120 are insulated by the separator 130 and are arranged alternately in the thickness direction (second direction D2).

[0014] Each negative electrode 120 is formed in 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 has a negative electrode current collector foil 122 and negative electrode active material layers 124 provided on both sides of the negative electrode current collector foil 122. The negative electrode current collector foil 122 has a negative electrode tab 122n (see FIG. 3) on which the negative electrode active material layer 124 is not provided. The negative electrode tab 122n protrudes toward one side in the first direction D1.

[0015] Each positive electrode 110 is formed in a rectangular shape with its longitudinal axis extending in the first direction D1 and its transverse axis extending in the third direction D3. Each positive electrode 110 has a positive electrode current collector foil 112 and positive electrode active material layers 114 provided on both sides of the positive electrode current collector foil 112 in the second direction D2. The positive electrode current collector foil 112 has a positive electrode tab 112p (see FIG. 3) on which the positive electrode active material layer 114 is not provided. The positive electrode tab 112p protrudes toward the other side in the first direction D1.

[0016] The separator 130 provides insulation between the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ions to pass through. The separator 130 is formed in a zigzag shape.

[0017] The separator 130 has a rectangular shape before being folded in a zigzag shape. The separator 130 is disposed between the positive electrode 110 and the negative electrode 120 while being folded in 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.

[0018] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120 that are adjacent to each other in the second direction D2. In other words, each intervening portion 132a has the function of insulating the positive electrode 110 and the negative electrode 120 from each other. Each intervening portion 132a is formed of a rectangular region.

[0019] Each first folded portion 132b connects one end portion in the third direction D3 of adjacent intervening portions 132a in the second direction D2 so that the positive electrode 110 is located therebetween. The first folded portion 132b is disposed on one side (above) of the positive electrode 110 in the third direction D3.

[0020] Each second folded portion 132c connects the other end portions in the third direction D3 of the intervening portions 132a that are adjacent to each other in the second direction D2 so that the negative electrode 120 is located therebetween. The second folded portion 132c is disposed on the other side (below) of the negative electrode 120 in the third direction D3.

[0021] The outermost covering portion 132d collectively covers each of the first folded portions 132b and each of the second folded portions 132c. More specifically, the outermost covering portion 132d collectively covers all of the positive electrodes 110, all of the negative electrodes 120, all of the intervening portions 132a, all of the first folded portions 132b, and all of the second folded portions 132c while being wound around a central axis parallel to the first direction D1. The end 132e of the outermost covering portion 132d is set in 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 this embodiment, the end 132e of the outermost covering portion 132d is located below each of the positive electrodes 110 and each of the negative electrodes 120. Note that the peripheral surfaces and bottom surfaces of the multiple positive electrodes 110, the multiple negative electrodes 120, and the separator 130 may be covered with an insulating film (not shown).

[0022] The cell case 200 houses the electrode assembly 100. The cell case 200 has a substantially rectangular parallelepiped shape. The cell case 200 is configured so 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. The cell case 200 is also configured so that the dimension in the third direction D3 is longer than the dimension in the second direction D2.

[0023] The cell case 200 accommodates the electrode assembly 100 and an electrolyte (not shown) inside. The cell case 200 has a cylindrical main body 210, a first sealing member 510, and a second sealing member 610.

[0024] The cylindrical main body 210 has a first opening 218 and a second opening 219 formed at each end in the first direction D1. The first opening 218 is provided on one side in the first direction D1, and the second opening 219 is provided on the other side in the first direction D1. The cylindrical main body 210 is formed by molding a film F into a cylindrical shape. A specific method for molding the cylindrical main body 210 will be described later.

[0025] The cylindrical main body 210 has a bottom surface 211 , a first side surface 212 , a second side surface 213 , a top surface 214 , and a band-shaped portion 215 .

[0026] The bottom surface portion 211 is located on one side in the third direction D3. The bottom surface portion 211 has a rectangular outer shape when viewed in the third direction D3.

[0027] The first side surface portion 212 stands up along the third direction D3 from one end in the second direction D2 of the bottom surface portion 211. The second side surface portion 213 stands up along the third direction D3 from the other end in the second direction D2 of the bottom surface portion 211. The first side surface portion 212 and the second side surface portion 213 have a rectangular outer shape when viewed from the second direction D2.

[0028] The top surface portion 214 is located on the other side in the third direction D3. The top surface portion 214 has a rectangular outer shape when viewed in the third direction D3. The top surface portion 214 connects the upper ends of the first side surface portion 212 and the second side surface portion 213 to each other. In this embodiment, the top surface portion 214 extends from the first side surface portion 212. The top surface portion 214 is connected to the second side surface portion 213 via a strip portion 215.

[0029] The strip portion 215 is formed by joining a first end portion FE1 and a second end portion FE2 located at both ends of the film F together.

[0030] The strip portion 215 extends along the first direction D1. The strip portion 215 extends to the outside of the cell casing 200. As described above, in this 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.

[0031] First opening 218 is formed by one end of bottom surface portion 211, first side surface portion 212, second side surface portion 213 and top surface portion 214, and second opening 219 is formed by the other end thereof.

[0032] First sealing member 510 closes first opening 218. First sealing member 510 has first plate-shaped portion 511 and first extending portion 512.

[0033] The first plate-shaped portion 511 has a flat plate shape. The first plate-shaped portion 511 extends parallel to an imaginary plane perpendicular to the first direction D1 in which the first opening 218 and the second opening 219 are aligned. That is, the first plate-shaped portion 511 extends parallel to both the second direction D2 and the third direction D3. The first plate-shaped portion 511 is adjacent to the first opening 218 in the first direction D1. The first plate-shaped portion 511 is made of a metal such as aluminum. A negative electrode member 520 is provided on the first plate-shaped portion 511.

[0034] A pressure release valve 515 is provided on the first plate-shaped portion 511. The pressure release valve 515 is provided so as to rupture when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 515 ruptures, gas inside the cell case 200 is discharged to the outside of the cell case 200, and the internal pressure inside the cell case 200 decreases.

[0035] The first extending portion 512 extends in the first direction D1 from the first plate-shaped portion 511. The first extending portion 512 is disposed inside the cylindrical main body portion 210 (see FIG. 3). The first extending portion 512 extends along the inner circumferential surface 210S of the cylindrical main body portion 210, and has a cylindrical outer shape (see FIG. 2). Specifically, the first extending portion 512 has a rectangular cylindrical outer shape. The first extending portion 512 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

[0036] The first extending portion 512 has an inner layer portion 512a and an outer layer portion 512b. The inner layer portion 512a is integrally formed 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 welding.

[0037] 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.

[0038] The negative electrode terminal plate 521 is formed in a substantially rectangular parallelepiped shape. The negative electrode 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 electrode terminal plate 521. Each of the negative electrode terminal plate 521 and the insulating plate 522 is provided with a through hole through which a negative electrode connecting pin 533 (described later) is inserted.

[0039] Second sealing member 610 closes second opening 219. Second sealing member 610 has second plate-shaped portion 611 and second extending portion 612.

[0040] The second plate-shaped portion 611 has a flat plate shape. The second plate-shaped portion 611 extends parallel to an imaginary plane perpendicular to the first direction D1. That is, the second plate-shaped portion 611 extends parallel to both the second direction D2 and the third direction D3. The second plate-shaped portion 611 is adjacent to the second opening 219 in the first direction D1. The second plate-shaped portion 611 is made of a metal such as aluminum. A positive electrode member 620 is provided on the second plate-shaped portion 611.

[0041] The second plate-shaped portion 611 is provided with a pressure release valve 615. The pressure release valve 615 is provided so as to rupture when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 615 ruptures, gas inside the cell case 200 is discharged to the outside of the cell case 200, thereby reducing the internal pressure inside the cell case 200.

[0042] The second extending portion 612 extends in the first direction D1 from the second plate-shaped portion 611. The second extending portion 612 is disposed inside the cylindrical main body portion 210 (see FIG. 3). The second extending portion 612 extends along the inner circumferential surface 210S of the cylindrical main body portion 210, and has a cylindrical outer shape (see FIG. 2). Specifically, the second extending portion 612 has a rectangular cylindrical outer shape. The second extending portion 612 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

[0043] The second extending portion 612 has an inner layer portion 612a and an outer layer portion 612b. The inner layer portion 612a is integrally formed 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 welding.

[0044] 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.

[0045] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0046] The terminal block 622 is formed in a rectangular parallelepiped shape. The terminal block 622 is made of a metal (such as iron) different from the metal making up 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 with the same polarity as the positive terminal plate 621. A through hole is formed in each of the positive terminal plate 621 and the terminal block 622, through which a positive connecting pin 633 (described later) is inserted.

[0047] An insulating plate may be disposed between the positive electrode component 620 and the second plate-shaped portion 611, so that the positive electrode component 620 and the second sealing member 610 are electrically insulated from each other. In this case, an insulating plate may be disposed instead of the terminal block 622, or the terminal block 622 and the second plate-shaped portion 611 may be electrically insulated from each other. An insulating plate may be disposed between the portion 611 and the insulating plate.

[0048] The energy storage cell 10 further includes a negative electrode connecting member 530, a negative electrode insulating member 550, and an insulator 560 on the negative electrode member 520 side.

[0049] The negative electrode connecting member 530 connects the negative electrode current collector 120N and the negative electrode terminal plate 521. The negative electrode current collector 120N is a portion of the electrode body 100 formed by bundling together a plurality of negative electrode tabs 122n (described later). The negative electrode connecting member 530 includes a negative electrode first current collector 531, a negative electrode second current collector 532, and a negative electrode connecting pin 533.

[0050] The negative electrode first current collector 531 is made of a thin plate-like conductive member and is connected to the negative electrode current collector 120N by laser welding, ultrasonic welding, or the like.

[0051] The negative electrode second current collector 532 is made of a thin plate-like conductive member. The negative electrode second current collector 532 is connected to the negative electrode first current collector 531 by laser welding, ultrasonic welding, or the like. The negative electrode second current collector 532 has a holding portion 532a that holds 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, and the base end of the negative electrode connecting pin 533 is inserted into the through hole.

[0052] The negative electrode connecting pin 533 connects the negative electrode second current collector 532 and the negative electrode terminal plate 521. The negative electrode connecting pin 533 includes a cylindrical portion. The tip side of the cylindrical portion penetrates the first sealing body 510, the insulating plate 522, and the negative electrode terminal plate 521, and is crimped to the negative electrode terminal plate 521.

[0053] The negative electrode side insulating member 550 is disposed between the first extending 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.

[0054] The first extending portion 512 and the negative electrode side insulating member 550 are assembled to each other so that an accommodation space is formed between the first plate-shaped portion 511 and the negative electrode side insulating member 550. The negative electrode current collector 120N, the negative electrode side first current collector 531, and the negative electrode side second current collector 532 inserted through the slits 552 are arranged in the accommodation space.

[0055] The insulator 560 has a shape that covers the columnar portion of the negative electrode connecting pin 533. The insulator 560 insulates the negative electrode connecting pin 533 from the cell case 200 (more specifically, the first plate-shaped portion 511).

[0056] The negative electrode member 520, the first sealing member 510, the negative electrode connecting member 530, the negative electrode side insulating member 550, and the insulator 560 are assembled together to form the first lid assembly 50.

[0057] The first lid assembly 50 is fixed to the cylindrical main body 210 by attaching the first sealing body 510 to the first opening 218 with the negative electrode current collecting portion 120N and the negative electrode connecting member 530 fixed by welding or the like.

[0058] The energy storage cell 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.

[0059] The positive electrode connecting member 630 connects the positive electrode current collecting portion 110P and the positive electrode terminal plate 621. The current collector 110P is a portion of the electrode assembly 100 formed by bundling together a plurality of positive electrode tabs 112p (described later). The positive electrode connecting member 630 includes a positive electrode first current collector 631, a positive electrode second current collector 632, and a positive electrode connecting pin 633.

[0060] The positive electrode first current collector 631 is made of a thin plate-like conductive material and is connected to the positive electrode current collector 110P by laser welding, ultrasonic welding, or the like.

[0061] The positive electrode side second current collector 632 is made of a thin plate-like conductive material. The positive electrode side second current collector 632 is connected to the positive electrode side first current collector 631 by laser welding, ultrasonic welding, or the like. The positive electrode side second current collector 632 has a holding portion 632a that holds 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, and the base end of the positive electrode connecting pin 633 is inserted into the through hole.

[0062] The positive electrode connecting pin 633 connects the positive electrode second current collector 632 and the positive electrode terminal plate 621. The positive electrode connecting pin 633 includes a cylindrical portion. The tip side of the cylindrical portion penetrates the second sealing body 610, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0063] The positive electrode side insulating member 650 is disposed between the second extending 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.

[0064] The second extending portion 612 and the positive electrode side insulating member 650 are assembled to each other so that an accommodation space is formed between the second plate-shaped portion 611 and the positive electrode side insulating member 650. The positive electrode current collector 110P, the positive electrode side first current collector 631, and the positive electrode side second current collector 632 inserted through the slits 552 are arranged in the accommodation space.

[0065] The insulator 660 has a shape that covers the cylindrical portion of the positive electrode connecting pin 633. The insulator 660 insulates the positive electrode connecting pin 633 from the cell case 200 (more specifically, the second plate-shaped portion 611).

[0066] The positive electrode member 620, the second sealing member 610, the positive electrode connecting member 630, the positive electrode side insulating member 650, and the insulator 660 are assembled together to form the second lid assembly 60.

[0067] The second lid assembly 60 is fixed to the cylindrical main body 210 by attaching the second sealing body 610 to the second opening 219 with the positive electrode current collecting portion 110P and the positive electrode connecting member 630 fixed by welding or the like.

[0068] A method for forming the cylindrical main body portion 210 using the film F will be described below. Fig. 5 is a perspective view schematically showing a state in the middle of forming a cell case in an energy storage cell according to one embodiment. In Fig. 5, the same reference numerals as those of the corresponding parts of the cylindrical main body portion 210 are used for the parts of the film F.

[0069] In this embodiment, the method for forming the cylindrical main body portion 210 includes three welding steps. As shown in FIGS. 1 to 3 and 5, 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 extending portion 512 and the second extending portion 612 (see FIG. 5, etc.). Next, in the second welding step, the portion of the film F corresponding to the top surface portion 214 is heat-welded to the first extending portion 512 and the second extending portion 612 (see FIG. 5, etc.). In the third welding step, the first side end portion FE1 and the second side end portion FE2 are heat-welded to each other. This forms the cylindrical main body 210, and the cylindrical main body 210 is sealed by the first sealing member 510 and the second sealing member 610. The order of the second welding step and the third welding step is not particularly limited.

[0070] After the first welding step and before the second and third welding steps, an electrolyte solution is injected (see FIG. 5). Specifically, the electrolyte solution is injected through the injection tube P into the space formed by the film F, the first sealing member 510, and the second sealing member 610. By configuring the cylindrical main body 210 from the film F in this way, even if the cylindrical main body 210 is relatively long in the first direction D1, the electrolyte solution can be easily injected throughout the entire cylindrical main body 210 in the first direction D1.

[0071] Next, we will explain the film that constitutes the cylindrical main body 210. Fig. 6 is an enlarged partial cross-sectional view of region VI in Fig. 3.

[0072] 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.

[0073] The resin layer L1 forms the inner circumferential surface 210S of the cylindrical main body 210. An outer layer portion 512b made of resin of the first extending portion 512 is heat-welded to the resin layer L1. Similarly, an outer layer portion 612b made of resin of the second extending portion 612 is heat-welded to the resin layer L1.

[0074] Examples of materials for the resin layer L1 include olefin-based resins such as polypropylene (PP) and polyethylene (PE). The thickness of the resin layer L1 is, for example, 40 μm or more and 100 μm or less. The resin layer L1 may include a plurality of resin films made of the above materials.

[0075] The metal layer L2 is laminated on the resin layer L1. This reduces the moisture permeability of the film F. Examples of materials for 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.

[0076] The second resin layer L3 is laminated on the metal layer L2 on the side opposite to the resin layer L1 as viewed from the metal layer L2. Examples of materials for the second resin layer L3 include polyethylene terephthalate (PET) and nylon. The thickness of the resin layer is, for example, 20 μm or more and 60 μm or less. The second resin layer L3 may include multiple resin films made of the above materials.

[0077] As described above, the energy storage cell 10 according to one embodiment of the present disclosure includes an electrode assembly 100 and a cell casing 200. The cell casing 200 houses the electrode assembly 100. The cell casing 200 has a cylindrical main body 210, a first sealing body 510, and a second sealing body 610. The cylindrical main body 210 is formed by molding a film F into a cylindrical shape. A first opening 218 and a second opening 219 are formed at each end of the cylindrical main body 210. 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 a first plate-shaped portion 511 and a first extending portion 512. The first plate-shaped portion 511 extends parallel to an imaginary plane perpendicular to the first direction D1 in which the first opening 218 and the second opening 219 are aligned. The first plate-shaped portion 511 is adjacent to the first opening 218 in the first direction D1. The first extending portion 512 extends from the first plate-shaped portion 511 in the first direction D1. The first extending portion 512 is disposed inside the cylindrical main body portion 210. The first extending portion 512 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

[0078] According to the above configuration, the cylindrical main body portion 210 of the cell case 200 is formed from the film F, which increases the dimensional flexibility of the cell case 200 in the first direction D1. Furthermore, even when the cylindrical main body portion 210 is formed from the film F, the first sealing body 510 has the first extending portion 512, which tightly bonds the first sealing body 510 and the inner circumferential surface 210S of the cylindrical main body portion 210 to each other. As a result, even when the cylindrical main body portion 210 of the cell case 200 is formed from the film F, it is possible to suppress a decrease in the sealing performance of the cell case 200.

[0079] The first extending portion 512 extends along the inner circumferential surface 210S of the cylindrical main body 210, and has a cylindrical outer shape.

[0080] According to the above configuration, the first extending portion 512 can be in closer contact with the cylindrical main body portion 210, so that the deterioration of the sealing performance of the cell case 200 can be further suppressed.

[0081] The film F also includes a resin layer L1 and a metal layer L2. The resin layer L1 forms the inner circumferential surface 210S of the cylindrical main body 210. The metal layer L2 is laminated on the resin layer L1. The first extending portion 512 has an inner layer portion 512a and an outer layer portion 512b. The inner layer portion 512a is integrally formed with the first plate-shaped portion 511. The outer layer portion 512b is disposed between the inner layer portion 512a and the cylindrical main body 210. The outer layer portion 512b is made of resin and is heat-sealed to the resin layer L1 of the film F.

[0082] According to the above configuration, the first extending portion 512 and the cylindrical main body portion 210 are joined together more tightly by thermal welding, so that the deterioration of the sealing performance of the cell case 200 can be further suppressed.

[0083] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0084] 10 Energy storage cell, 50 First lid assembly, 60 Second lid assembly, 100 Electrode body, 110 Positive electrode, 110P Positive electrode current collector, 112 Positive electrode current collector foil, 112p Positive electrode tab, 114 Positive electrode active material layer, 120 Negative electrode, 120N Negative electrode current collector, 122 Negative electrode current collector foil, 122n Negative electrode tab, 124 Negative electrode active material layer, 130 Separator, 132a Interposition portion, 132b First folded portion, 132c Second folded portion, 132d Outermost coating portion, 132e End, 200 Cell case, 210 Cylindrical main body portion, 210S Inner peripheral surface, 211 Bottom surface portion, 212 First side surface portion, 213 Second side surface portion, 214 Top surface portion, 215 Strip portion, 218 First opening, 219 Second opening, 510 First sealing body, 511 First plate-shaped portion, 512 First extension portion, 512a Inner layer portion, 512b Outer layer portion, 515 Pressure release valve, 520 Negative electrode member, 521 Negative electrode terminal plate, 522 Insulating plate, 530 Negative electrode connecting member, 531 First current collector, 532 Second current collector, 532a Holding portion, 533 Negative electrode connecting pin, 550 Negative electrode side insulating member, 552 Slit, 560 Insulator, 610 Second sealing body, 611 Second plate-shaped portion, 612 Second extension portion, 612a Inner layer portion, 612b Outer layer portion, 615 Pressure release valve, 620 Positive electrode member, 621 Positive electrode terminal plate, 622 Terminal block, 630 Positive electrode connecting member, 631 First current collector, 632 second current collector, 632a holding portion, 633 positive electrode connecting pin, 650 positive electrode side insulating member, 652 slit, 660 insulator, F film, FE1 first side end portion, FE2 second side end portion, L1 resin layer, L2 metal layer, L 3 Second resin layer, P Injection tube.

Claims

1. An electrode body; a cell case that houses the electrode body, The cell casing is a cylindrical main body portion formed by molding a film into a cylindrical shape, the cylindrical main body portion having a first opening and a second opening formed at both ends thereof; a first sealing body that closes the first opening; a second sealing body that closes the second opening, the first sealing body includes a first plate-shaped portion extending parallel to an imaginary plane perpendicular to a first direction in which the first opening and the second opening are aligned, and adjacent to the first opening in the first direction; a first extending portion extending in the first direction from the first plate-shaped portion and disposed inside the cylindrical main body portion; The first extension portion is joined to an inner circumferential surface of the cylindrical main body portion.

2. The energy storage cell according to claim 1 , wherein the first extension portion extends along the inner circumferential surface of the cylindrical main body portion and has a cylindrical outer shape.

3. the film includes a resin layer that forms the inner circumferential surface of the cylindrical main body portion and a metal layer that is laminated on the resin layer, the first extending portion has an inner layer portion integrally formed with the first plate-shaped portion and an outer layer portion disposed between the inner layer portion and the cylindrical main body portion, The energy storage cell according to claim 1 or 2, wherein the outer layer portion is made of resin and is welded to the resin layer of the film.

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