Power storage cell

Abstract

To improve a degree of dimension freedom of a cell case in one direction and suppress reduction in sealing properties of the cell case.SOLUTION: In a cell case 200 of a power storage cell 10, a cylindrical main body part 210 is configured by cylindrically molding a film F, and a first opening 218 and a second opening 219 are formed in both ends. A first sealing body 510 closes the first opening 218. A second sealing body 610 closes the second opening 219. The first sealing body 510 includes an outer peripheral surface 511S in contact with an inner peripheral surface 210S of the cylindrical main body part 210. The outer peripheral surface 511S includes a main body surface portion 511Sa and a protruding portion 511Sb. The main body surface portion 511Sa extends in parallel with a first direction D1 in which the first opening 218 and the second opening 219 are disposed side by side. The protruding portion 511Sb protrudes from the main body surface part 511Sa toward the cylindrical main body part 210.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Patent Document 1 (JP 2019-106372 A) discloses a battery having a battery case and an electrode assembly. The battery case includes a housing that houses the electrode assembly and a lid. The lid covers at least a portion of the open surface of the housing. After the electrode assembly is placed and the electrolyte is injected, the open surface of the housing is hermetically sealed or sealed with the lid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-106372 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the cell case of the battery as disclosed in Patent Document 1, it is important to suppress the deterioration of the sealing property in order to suppress the fluctuation of the moisture amount in the cell case. In addition, when the storage cell is used, for example, for in-vehicle use, it is required to make the storage cell lower in height and to increase the dimension in one of the lateral directions of the storage cell in order to suppress the decrease in energy density. However, in the conventional storage cell, it is difficult to manufacture a cell scale having a longer dimension in the one direction. Therefore, there is a restriction on the dimension in the one direction.

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

[0006] The 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 includes 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, and a first opening and a second opening are formed at each end. The first sealing body closes the first opening. The second sealing body closes the second opening. The first sealing body has an outer peripheral surface that contacts the inner peripheral surface of the cylindrical main body. The outer peripheral surface includes 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 and the second opening are aligned. The protruding portion protrudes from the main body surface portion toward the cylindrical main body.

[0007] According to the above configuration, since the cylindrical main body of the cell case is formed from a film, the dimensional freedom of the cell case in the first direction can be increased. Furthermore, even when the cylindrical main body is formed from a film, a labyrinth structure is formed between the inner peripheral surface of the cylindrical main body and the outer peripheral surface of the first sealing body by the main body surface portion and the protruding portion. This makes it possible to suppress a decrease in the sealing performance of the cell case, even when the cylindrical main body of the cell case is formed from a film. Effect of the Invention

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

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

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0011] Fig. 1 is a perspective view showing a storage cell according to an embodiment. Fig. 2 is an exploded perspective view of a storage cell according to an embodiment. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1. As shown in Figs. 1 to 3, a storage cell 10 according to an embodiment includes an electrode body 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. The electrode assembly 100 will be described in detail with reference to Fig. 4.

[0013] 4, the electrode body 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 arranged alternately in the thickness direction (second direction D2) while being insulated by the separator 130.

[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 a negative electrode active material layer 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 longer side in the first direction D1 and its shorter side 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 interposed portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0018] Each interposed portion 132a is interposed between the positive electrode 110 and the negative electrode 120 adjacent to each other in the second direction D2. That is, each interposed portion 132a has a function of insulating the positive electrode 110 and the negative electrode 120. Each interposed 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 intermediate 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 intermediate portions 132a 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 covers each of the first folded portions 132b and each of the second folded portions 132c collectively. More specifically, the outermost covering portion 132d 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 collectively 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 provided below each of the positive electrodes 110 and each of the negative electrodes 120. 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 body 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) therein. The cell case 200 has a cylindrical main body 210, a first sealing body 510, and a second sealing body 610.

[0024] A first opening 218 and a second opening 219 are formed on each of both ends in the first direction D1 of the cylindrical main body 210. 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 the 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 portion 211 , a first side surface portion 212 , a second side surface portion 213 , a top surface portion 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 from 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 band-shaped portion 215.

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

[0030] The strip portion 215 extends along the first direction D1. The strip portion 215 extends to the outside of the cell case 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 ends thereof.

[0032] The first sealing body 510 closes the first opening 218. The first sealing body 510 has a (first) outer peripheral surface 511S that contacts the inner peripheral surface 210S of the cylindrical main body 210. In this embodiment, the entire first sealing body 510 is located on the inner peripheral surface 210S side of the cylindrical main body 210.

[0033] Fig. 5 is an enlarged partial cross-sectional view of region V in Fig. 3. As shown in Fig. 2, Fig. 3, and Fig. 5, outer circumferential surface 511S has a (first) main body surface portion 511Sa and a (first) protruding portion 511Sb.

[0034] The main body surface portion 511Sa extends parallel to a first direction D1 in which the first opening 218 and the second opening 219 are aligned (see FIG. 5). The protrusion 511Sb protrudes from the main body surface portion 511Sa toward the cylindrical main body 210. The protrusion 511Sb extends annularly along the circumferential direction of the inner peripheral surface 210S of the cylindrical main body 210 (see FIG. 2).

[0035] The first sealing body 510 has a first plate-shaped portion 511 and a first extending portion 512. Specifically, the first plate-shaped portion 511 has the outer circumferential surface 511S described above.

[0036] The first plate-shaped portion 511 has a flat plate shape. The first plate-shaped portion 511 extends parallel to a virtual 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 is located on the inner circumferential surface 210S side of the cylindrical main body 210. The first plate-shaped portion 511 is made of a metal such as aluminum. The first plate-shaped portion 511 is provided with a negative electrode member 520.

[0037] The first plate-shaped portion 511 is provided with a pressure release valve 515. The pressure release valve 515 is provided so as to break when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 515 breaks, gas within the cell case 200 is discharged to the outside of the cell case 200, and the internal pressure within the cell case 200 decreases.

[0038] 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 on the inner circumferential surface 210S side of 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.

[0039] 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.

[0040] 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.

[0041] 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 between the first plate-shaped portion 511 and 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 for inserting a negative electrode connecting pin 533 described later.

[0042] The second sealing body 610 closes the second opening 219. The second sealing body 610 has a second outer peripheral surface 611S that contacts the inner peripheral surface 210S of the cylindrical main body 210. In this embodiment, the entire second sealing body 610 is located on the inner peripheral surface 210S side of the cylindrical main body 210.

[0043] The second outer circumferential surface 611S has a second main body surface portion 611Sa and a second protrusion portion 611Sb.

[0044] The second main body surface portion 611Sa extends parallel to the first direction D1. The second protrusion portion 611Sb protrudes from the second main body surface portion 611Sa toward the cylindrical main body portion 210. The second protrusion portion 611Sb extends annularly along the circumferential direction of the inner peripheral surface 210S of the cylindrical main body portion 210.

[0045] The second sealing body 610 has a second plate-shaped portion 611 and a second extending portion 612. Specifically, the second plate-shaped portion 611 has the above-mentioned second outer circumferential surface 611S.

[0046] The second plate-shaped portion 611 has a flat plate shape. The second plate-shaped portion 611 extends parallel to a virtual 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 located on the inner circumferential surface 210S side of the cylindrical main body 210. The second plate-shaped portion 611 is made of a metal such as aluminum. The second plate-shaped portion 611 is provided with a positive electrode member 620.

[0047] The second plate-shaped portion 611 is provided with a pressure release valve 615. The pressure release valve 615 is provided so as to break when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 615 breaks, gas within the cell case 200 is discharged to the outside of the cell case 200, and the internal pressure within the cell case 200 decreases.

[0048] The second extending portion 612 extends from the second plate-shaped portion 611 in the first direction D1. The second extending portion 612 is disposed on the inner circumferential surface 210S side of 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.

[0049] 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. In other words, 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.

[0050] 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.

[0051] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0052] 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 constituting the positive electrode 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 electrode 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 electrode terminal plate 621 via the terminal block 622, and is charged with the same polarity as the positive electrode terminal plate 621. Each of the positive electrode terminal plate 621 and the terminal block 622 has a through hole formed therein for inserting a positive electrode connecting pin 633 described later.

[0053] 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 body 610 are electrically insulated from each other. In this case, an insulating plate may be disposed instead of the terminal block 622, or an insulating plate may be disposed between the terminal block 622 and the second plate-shaped portion 611.

[0054] The energy storage cell 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 columnar portion. The tip side of the columnar 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.

[0059] 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.

[0060] 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 disposed in the accommodation space.

[0061] The insulator 560 has a shape that covers the columnar portion of the negative electrode connecting pin 533. The insulator 560 provides insulation between the negative electrode connecting pin 533 and the cell casing 200 (more specifically, the first plate-shaped portion 511).

[0062] 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 assembled together to form the first lid assembly 50.

[0063] 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.

[0064] 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.

[0065] The positive electrode connecting member 630 connects the positive electrode current collector 110P and the positive electrode terminal plate 621. The positive electrode current collector 110P is a portion of the electrode body 100 formed by bundling together a plurality of positive electrode tabs 112p (described later). 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.

[0066] The positive electrode first current collector 631 is made of a thin plate-like conductive member and is connected to the positive electrode current collector 110P by laser welding, ultrasonic welding, or the like.

[0067] The positive electrode side second current collector 632 is configured of a thin plate-like conductive member. 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 it.

[0068] 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. A 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.

[0069] 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.

[0070] 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 disposed in the accommodation space.

[0071] The insulator 660 has a shape that covers the columnar portion of the positive electrode connecting pin 633. The insulator 660 provides insulation between the positive electrode connecting pin 633 and the cell case 200 (more specifically, the second plate-shaped portion 611).

[0072] The positive electrode member 620 , the second sealing body 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 .

[0073] 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 current collecting portion 110P and the positive connecting member 630 fixed by welding or the like.

[0074] Hereinafter, a method for forming the cylindrical main body portion 210 using the film F will be described. Fig. 6 is a perspective view that shows a schematic view of a state in the middle of forming a cell case in an energy storage cell according to one embodiment. In Fig. 6, the same reference numerals as those of the corresponding parts of the cylindrical main body portion 210 are used for the respective parts of the film F.

[0075] In this embodiment, the method for forming the cylindrical main body portion 210 includes three welding steps. As shown in Fig. 1 to Fig. 3 and Fig. 6, in the first welding step, the film F is folded while 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. 6, etc.). At the same time, the above-mentioned portions of the film F may be bonded to the (first) outer peripheral surface 511S and the second outer peripheral surface 611S by an adhesive or the like.

[0076] Next, in a 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. 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 by an adhesive or the like.

[0077] Finally, in a third welding step, the first side end portion FE1 and the second side end portion FE2 are heat-welded to each other, thereby forming the cylindrical main body portion 210, and sealing the cylindrical main body portion 210 with 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.

[0078] After the first welding step and before the second and third welding steps, an electrolyte is injected (see FIG. 6). Specifically, the electrolyte is injected through the injection tube P into the space formed by the film F, the first sealing body 510, and the second sealing body 610. By forming the cylindrical main body 210 from the film F in this manner, even if the cylindrical main body 210 is relatively long in the first direction D1, the electrolyte can be easily injected throughout the entire area in the first direction D1.

[0079] Next, the film constituting the cylindrical main body 210 will be described. As shown in Fig. 5, 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.

[0080] The resin layer L1 constitutes the inner circumferential surface 210S of the cylindrical main body 210. In this embodiment, the resin layer L1 has a (first) hole H1 and a second hole H2. The hole H1 is fitted with the protruding portion 511Sb. The second hole H2 is fitted with the second protruding portion 611Sb. The hole H1 and the second hole H2 penetrate the resin layer L1. The hole H1 extends in an annular shape along the protruding portion 511Sb. The second hole H2 extends in an annular shape along the second protruding portion 611Sb.

[0081] The hole H1 and the second hole H2 may not be provided. When the hole H1 is not provided in the resin layer L1, the film F (the cylindrical main body 210) may be bent along the protruding portion 511Sb. When the second hole H2 is not provided in the resin layer L1, the film F (the cylindrical main body 210) may be bent along the second protruding portion 611Sb.

[0082] Furthermore, 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.

[0083] Examples of materials for 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 or more and 100 μm or less. The resin layer L1 may include a plurality of resin films made of the above materials.

[0084] The metal layer L2 is laminated on the resin layer L1. This can reduce the moisture permeability of the film F. Examples of materials for the metal layer L2 include aluminum, aluminum alloy, and stainless steel. The thickness of the metal layer L2 is, for example, 30 μm or more and 60 μm or less.

[0085] The second resin layer L3 is laminated on the metal layer L2 on the opposite side of the metal layer L2 from the resin layer L1. Examples of the material of 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 a plurality of resin films made of the above materials.

[0086] As described above, the energy storage cell 10 according to an embodiment of the present disclosure includes an electrode assembly 100 and a cell case 200. The cell case 200 houses the electrode assembly 100. The cell 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 each end. 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 that contacts the inner peripheral surface 210S of the cylindrical main body 210. The outer peripheral surface 511S includes 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 aligned. The protrusion 511Sb protrudes toward the cylindrical main body 210 from the main body surface portion 511Sa.

[0087] According to the above configuration, since the cylindrical main body portion 210 of the cell case 200 is formed from the film F, the dimensional freedom of the cell case 200 in the first direction D1 can be increased. Furthermore, even when the cylindrical main body portion 210 is formed from the film F, a labyrinth structure is formed between the inner peripheral surface 210S and the outer peripheral surface 511S by the main body surface portion 511Sa and the protruding portion 511Sb. As a result, even when the cylindrical main body portion 210 of the cell case 200 is formed from the film F, a decrease in the sealing property of the cell case 200 can be suppressed.

[0088] In this embodiment, the film F includes a resin layer L1 that constitutes the inner circumferential surface 210S of the cylindrical main body 210, and a metal layer L2 that is laminated on the resin layer L1. The resin layer L1 has a hole H1 that fits with the protrusion 511Sb.

[0089] According to the above-mentioned configuration, the thickness of the resin layer L1 between the metal layer L2 and the protruding portion 511Sb is relatively thin, which can reduce the moisture permeability between the metal layer L2 and the protruding portion 511Sb.

[0090] In this embodiment, the hole H1 penetrates the resin layer L1. The protrusion 511Sb is in contact with the metal layer L2 through the hole H1.

[0091] According to the above-mentioned configuration, the moisture permeability between the metal layer L2 and the protruding portion 511Sb can be further reduced.

[0092] In this embodiment, the protruding portion 511Sb extends annularly along the circumferential direction of the inner peripheral surface 210S of the cylindrical main body 210. The hole H1 extends annularly along the protruding portion 511Sb.

[0093] According to the above configuration, a labyrinth structure is formed over the entire circumferential direction of the inner circumferential surface 210S by the main body surface portion 511Sa and the protruding portion 511Sb. As a result, deterioration in the sealing performance of the cell case 200 can be further suppressed.

[0094] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0095] 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 portion, 213 Second side portion, 214 Top surface portion, 215 Strip portion, 218 First opening, 219 second opening, 510 first sealing body, 511 first plate-shaped portion, 511S outer circumferential surface, 511Sa main body surface portion, 511Sb protruding portion, 512 first extension portion, 512a, 612a inner layer portion, 512b, 612b outer layer portion, 515, 615 pressure release valve, 520 negative electrode member, 521 negative electrode terminal plate, 522 insulating plate, 530 negative electrode connecting member, 531, 631 first current collector, 532, 632 second current collector, 532a, 632a holding portion, 533 negative electrode connecting pin, 550 negative electrode side insulating member, 552, 652 slit, 560, 660 insulator, 610 second sealing body, 611 second plate-shaped portion, 611S Second outer peripheral surface, 611Sa second main body surface portion, 611Sb second protrusion portion, 612 second extension portion, 620 positive electrode member, 621 positive electrode terminal plate, 622 terminal block, 630 positive electrode connecting member, 633 positive electrode connecting pin, 650 positive electrode side insulating member, F film, FE1 first side end portion, FE2 second side end portion, H1 hole portion, H2 second hole portion, L1 resin layer, L2 metal layer, L3 second resin layer.

Claims

1. An electrode body; A cell case that houses the electrode assembly, The cell casing comprises: 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 each end; a first sealing body that closes the first opening; a second sealing body that closes the second opening, the first sealing body has an outer circumferential surface bonded to an inner circumferential surface of the cylindrical main body, A storage cell, wherein the outer peripheral surface has a main body surface portion extending parallel to a first direction in which the first opening and the second opening are aligned, and a protrusion protruding from the main body surface portion toward the cylindrical main body portion.

2. the film includes a resin layer that configures the inner circumferential surface of the cylindrical main body portion, and a metal layer that is laminated on the resin layer, The energy storage cell according to claim 1 , wherein the resin layer has a hole in which the protrusion is fitted.

3. The hole penetrates the resin layer, The energy storage cell according to claim 2 , wherein the protrusion is in contact with the metal layer through the hole.

4. The protrusion extends annularly along a circumferential direction of the inner peripheral surface of the cylindrical main body, The energy storage cell according to claim 2 or 3, wherein the hole extends in an annular shape along the protrusion.

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