Energy 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 a storage battery cell.

Background Art

[0002] Patent Document 1 (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 that houses the electrode assembly and a lid portion. The lid portion covers at least a part of the open surface of the housing portion. After the arrangement of the electrode assembly and the injection of the electrolytic solution, the open surface of the housing portion is sealed or closed with the lid portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For a cell case of a battery as disclosed in Patent Document 1, it is important to suppress a decrease in sealing performance in order to suppress fluctuations in the amount of moisture inside the cell case. Further, when the storage battery cell is used, for example, for in-vehicle use, it is required to make the storage battery cell lower in height and to increase the dimension in one direction in the lateral direction of the storage battery cell in order to suppress a decrease in energy density. However, in a conventional storage battery cell, it has been difficult to manufacture a cell case having a dimension longer in the above one direction. Therefore, there has been a restriction on the dimension in the above one direction.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a storage battery cell that can increase the dimensional freedom in one direction of the cell case and suppress a decrease in the sealing performance of the cell case.

Means for Solving the Problems

[0006] The energy storage cell according to this disclosure comprises an electrode body and a cell case. The cell case houses the electrode body. The cell case has a cylindrical body, a first sealing body, and a second sealing body. The cylindrical body is formed by molding a film into a cylindrical shape, and has a first opening and a second opening at each of its ends. The first sealing body closes the first opening. The second sealing body closes the second opening. The first sealing body has an outer surface that is in contact with the inner surface of the cylindrical body. The outer surface has a body surface portion and a protruding portion. The body surface portion extends parallel to the first direction in which the first opening and the second opening are aligned. The protruding portion projects from the body surface portion toward the cylindrical body.

[0007] According to the above configuration, since the cylindrical 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 body is formed from a film, a labyrinth structure is formed between the inner circumferential surface of the cylindrical body and the outer circumferential surface of the first sealing body by the body surface portion and the protruding portion. As a result, even when the cylindrical body of the cell case is formed from a film, a decrease in the sealing performance of the cell case can be suppressed. [Effects of the Invention]

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

[0009] [Figure 1] This is a perspective view showing a power storage cell according to one embodiment. [Figure 2] This is an exploded perspective view of a storage cell according to one embodiment. [Figure 3] This is a cross-sectional view along the line III-III shown in Figure 1. [Figure 4] This is a cross-sectional view along the line IV-IV shown in Figure 1. [Figure 5] This is a partial cross-sectional view showing an enlarged view of region V in Figure 3. [Figure 6]This is a schematic perspective view showing the process of forming the cell case in a storage cell according to one embodiment. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same numbers.

[0011] Figure 1 is a perspective view showing a storage cell according to one embodiment. Figure 2 is an exploded perspective view of the storage cell according to one embodiment. Figure 3 is a cross-sectional view along the line III-III shown in Figure 1. As shown in Figures 1 to 3, the storage cell 10 according to one embodiment comprises 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] Figure 4 is a cross-sectional view along the line IV-IV shown in Figure 1. For convenience, in Figure 4, the cell case 200 of the energy storage cell 10 is omitted, and only the electrode body 100 is shown. The details of the electrode body 100 will be explained with reference to Figure 4.

[0013] As shown in Figure 4, the electrode body 100 comprises a plurality of positive electrodes 110 and a plurality of negative electrodes 120, and a separator 130. The plurality of positive electrodes 110 and a 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 its length in the width direction (first direction D1) and its width direction (third direction D3) as the shorter side. The second direction D2 is perpendicular to the first direction D1. The third direction D3 is 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 Figure 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 the first direction D1 as its length and the third direction D3 as its width. Each positive electrode 110 has a positive electrode current collector foil 112 and a positive electrode active material layer 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 Figure 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 insulates the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ion permeation. The separator 130 is formed in a zigzag pattern.

[0017] 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.

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

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

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

[0021] The outermost covering portion 132d collectively covers each first folded portion 132b and each second folded portion 132c. More specifically, the outermost covering portion 132d collectively covers all the positive electrodes 110, all the negative electrodes 120, all the intervening portions 132a, all the first folded portions 132b, and all the second folded portions 132c while winding them around a central axis parallel to the first direction D1. The terminal 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 the present embodiment, the terminal 132e of the outermost covering portion 132d is provided below each positive electrode 110 and each negative electrode 120. Note that the circumferential surfaces and bottom surfaces of the plurality of positive electrodes 110, the plurality of 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 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. Also, the cell case 200 is configured such that the dimension in the third direction D3 is longer than the dimension in the second direction D2.

[0023] The cell case 200 houses the electrode body 100 and an electrolytic solution (not shown) inside. The cell case 200 has a cylindrical main body portion 210, a first sealing body 510, and a second sealing body 610.

[0024] The cylindrical body portion 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 body portion 210 is formed by molding a film F into a cylindrical shape. The specific molding method of the cylindrical body portion 210 will be described later.

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

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

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

[0028] The top surface portion 214 is located on the other side of the third direction D3. The top surface portion 214 has a rectangular 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, respectively. 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 the strip-shaped portion 215.

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

[0030] The strip-shaped portion 215 extends along the first direction D1. The strip-shaped portion 215 extends to the outside of the cell case 200. As described above, in this embodiment, the strip-shaped portion 215 connects the top surface portion 214 and the second side surface portion 213. However, the position of the strip-shaped portion 215 is not particularly limited. The strip-shaped portion 215 may connect the top surface portion 214 and the first side surface portion 212, or the bottom surface portion 211 and the first side surface portion 212, or the bottom surface portion 211 and the second side surface portion 213.

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

[0032] The first sealing body 510 closes the first opening 218. The first sealing body 510 has a (first) outer surface 511S that is in contact with the inner surface 210S of the cylindrical body portion 210. In this embodiment, the entirety of the first sealing body 510 is located on the side of the inner surface 210S of the cylindrical body portion 210.

[0033] Figure 5 is a partial cross-sectional view showing an enlarged view of region V in Figure 3. As shown in Figures 2, 3, and 5, the outer peripheral 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 the first direction D1, where the first opening 218 and the second opening 219 are aligned (see Figure 5). The protruding portion 511Sb protrudes from the main body surface portion 511Sa toward the cylindrical main body portion 210. The protruding portion 511Sb extends in an annular shape along the circumferential direction of the inner circumferential surface 210S of the cylindrical main body portion 210 (see Figure 2).

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

[0036] The first plate-like portion 511 has a flat plate shape. The first plate-like portion 511 extends parallel to a virtual plane perpendicular to the first direction D1, where the first opening 218 and the second opening 219 are aligned. That is, the first plate-like portion 511 is located on the inner circumferential surface 210S side of the cylindrical main body portion 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.

[0037] A pressure relief valve 515 is provided in the first plate-shaped portion 511. The pressure relief valve 515 is designed to rupture when the internal pressure of the cell case 200 exceeds a predetermined pressure. When the pressure relief valve 515 ruptures, the gas inside the cell case 200 is discharged to the outside of the cell case 200, causing the internal pressure inside the cell case 200 to decrease.

[0038] The first extension 512 extends from the first plate-like portion 511 in a first direction D1. The first extension 512 is positioned on the inner circumferential surface 210S side of the cylindrical main body portion 210 (see Figure 3). The first extension 512 extends along the inner circumferential surface 210S of the cylindrical main body portion 210 and has a cylindrical outer shape (see Figure 2). Specifically, the first extension 512 has a rectangular cylindrical outer shape. The first extension 512 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

[0039] The first extension 512 has an inner layer 512a and an outer layer 512b. The inner layer 512a is integrally molded with the first plate-like portion 511. That is, the first plate-like portion 511 is made of a metal such as aluminum. The outer layer 512b is positioned between the inner layer 512a and the cylindrical main body portion 210. The outer layer 512b is made of resin. The outer layer 512b is joined to the inner circumferential surface 210S of the cylindrical main body portion 210 by heat 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-like portion 511. The insulating plate 522 insulates the first plate-like portion 511 from the negative electrode terminal plate 521. Both the negative electrode terminal plate 521 and the insulating plate 522 are provided with through holes for inserting the negative electrode connecting pin 533, which will be described later.

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

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

[0044] The second main body surface portion 611Sa extends parallel to the first direction D1. The second projection portion 611Sb protrudes from the second main body surface portion 611Sa toward the cylindrical main body portion 210. The second projection portion 611Sb extends in an annular shape along the circumferential direction of the inner circumferential surface 210S of the cylindrical main body portion 210.

[0045] The second sealing body 610 has a second plate-like portion 611 and a second extension portion 612. Specifically, the second plate-like portion 611 has the second outer peripheral surface 611S described above.

[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 portion 210. 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.

[0047] A pressure relief valve 615 is provided in the second plate-shaped portion 611. The pressure relief valve 615 is designed to rupture when the internal pressure of the cell case 200 exceeds a predetermined pressure. When the pressure relief valve 615 ruptures, the gas inside the cell case 200 is discharged to the outside, causing the internal pressure inside the cell case 200 to decrease.

[0048] The second extension portion 612 extends from the second plate-like portion 611 in the first direction D1. The second extension portion 612 is positioned on the inner circumferential surface 210S side of the cylindrical main body portion 210 (see Figure 3). The second extension portion 612 extends along the inner circumferential surface 210S of the cylindrical main body portion 210 and has a cylindrical outer shape (see Figure 2). Specifically, the second extension portion 612 has a rectangular cylindrical outer shape. The second extension portion 612 is joined to the inner circumferential surface 210S of the cylindrical main body portion 210.

[0049] The second extension 612 has an inner layer 612a and an outer layer 612b. The inner layer 612a is integrally molded with the second plate-like portion 611. That is, the second plate-like portion 611 is made of a metal such as aluminum. The outer layer 612b is positioned between the inner layer 612a and the cylindrical main body portion 210. The outer layer 612b is made of resin. The outer layer 612b is joined to the inner circumferential surface 210S of the cylindrical main body portion 210 by heat 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 terminal plate 621 is formed in a rectangular parallelepiped shape. The positive terminal plate 621 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 different metal (such as iron) than the metal that makes 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. Through holes are formed in both the positive terminal plate 621 and the terminal block 622 for inserting the positive terminal connecting pin 633, which will be described later.

[0053] Furthermore, the positive electrode member 620 may have an insulating plate placed between it and the second plate-shaped portion 611, thereby electrically insulating the positive electrode member 620 from the second sealing body 610. In this case, the insulating plate may be placed instead of the terminal block 622, or the insulating plate may be placed 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 multiple negative electrode tabs 122n, which will be described later. 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.

[0056] The negative electrode side first current collector 531 is made of a thin plate-shaped conductive material. The negative electrode side first current collector 531 is connected to the negative electrode current collector 120N by laser welding or ultrasonic welding or the like.

[0057] The negative electrode side second current collector 532 is made of a thin plate-shaped conductive member. The negative electrode side second current collector 532 is connected to the negative electrode side first current collector 531 by laser welding or ultrasonic welding. The negative electrode side 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 into which the base end of the negative electrode connecting pin 533 is inserted.

[0058] 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 tip of this 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.

[0059] The negative electrode side insulating member 550 is positioned 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 collector portion 120N is inserted.

[0060] The first extension 512 and the negative electrode insulating member 550 are assembled together such that a accommodating space is formed between the first plate-shaped portion 511 and the negative electrode insulating member 550. The negative electrode current collector 120N inserted through the slit 552, the negative electrode first current collector 531, and the negative electrode second current collector 532 are arranged in this accommodating space.

[0061] The insulator 560 has a shape that covers the cylindrical 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 from 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 to constitute 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 collector 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 multiple positive electrode tabs 112p, which will be 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 side first current collector 631 is made of a thin plate-shaped conductive material. The positive electrode side first current collector 631 is connected to the positive electrode current collector 110P by laser welding or ultrasonic welding or the like.

[0067] The positive electrode side second current collector 632 is made of a thin plate-shaped conductive material. The positive electrode side second current collector 632 is connected to the positive electrode side first current collector 631 by laser welding or ultrasonic welding. 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 into which the base end of the positive electrode connecting pin 633 is inserted.

[0068] 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 tip of this cylindrical portion passes through 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 positioned 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 collector portion 110P is inserted.

[0070] The second extension 612 and the positive electrode side insulating member 650 are assembled together such that a accommodating 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 are arranged in this accommodating space, with the positive electrode current collector 110P inserted through the slit 552 being positioned within it.

[0071] 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 from 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 to constitute the second lid assembly 60.

[0073] The second cover 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 collector 110P and the positive electrode connecting member 630 fixed together by welding or the like.

[0074] The following describes a method for forming the cylindrical body portion 210 using the film F. Figure 6 is a schematic perspective view showing the process of forming the cell case in a storage cell according to one embodiment. In Figure 6, each part of the film F is denoted by the same reference numerals as the parts corresponding to the cylindrical body portion 210.

[0075] In this embodiment, the method for forming the cylindrical body portion 210 includes three welding steps. As shown in Figures 1 to 3 and Figure 6, in the first welding step, while folding the film F, the portions of the film F corresponding to the bottom portion 211, the first side portion 212, and the second side portion 213 are heat-welded to the first extension portion 512 and the second extension portion 612 (see Figure 6, etc.). At the same time, the above portions of the film F may be bonded to the (first) outer peripheral surface 511S and the second outer peripheral surface 611S with an adhesive or the like.

[0076] Next, in the second welding step, the portion of the film F corresponding to the top surface 214 is heat-welded to the first extension 512 and the second extension 612. At the same time, the portion of the film F corresponding to the top surface 214 may be bonded to the (first) outer peripheral surface 511S and the second outer peripheral surface 611S using an adhesive or the like.

[0077] Finally, in the third welding step, the first end portion FE1 and the second end portion FE2 are heat-welded together. This forms the cylindrical body portion 210, and the cylindrical body portion 210 is sealed by the first sealing body 510 and the second sealing body 610. The order of the second and third welding steps described above is not particularly limited.

[0078] Furthermore, after the first welding step and before the second and third welding steps, the electrolyte is injected (see Figure 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. In this way, by constructing the cylindrical body portion 210 from the film F, the injection of the electrolyte can be easily carried out over the entire length in the first direction D1, even when the cylindrical body portion 210 is relatively long in the first direction D1.

[0079] Next, the film constituting the cylindrical body portion 210 will be described. As shown in Figure 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 portion 210. In this embodiment, the resin layer L1 has a (first) hole H1 and a second hole H2. Hole H1 is fitted with the projection 511Sb. The second hole H2 is fitted with the second projection 611Sb. Hole H1 and the second hole H2 penetrate the resin layer L1. Hole H1 extends in an annular shape along the projection 511Sb. The second hole H2 extends in an annular shape along the second projection 611Sb.

[0081] Note that the holes H1 and the second hole H2 are not required. If the resin layer L1 does not have a hole H1, the film F (tubular body portion 210) may be bent along the protrusion 511Sb. If the resin layer L1 does not have a second hole H2, the film F (tubular body portion 210) may be bent along the second protrusion 611Sb.

[0082] Furthermore, the outer layer portion 512b of the first extension portion 512, which is made of resin, is heat-welded to the resin layer L1. Similarly, the outer layer portion 612b of the second extension portion 612, which is made of resin, 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 to 100 μm. The resin layer L1 may also contain multiple resin films made of the above materials.

[0084] 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 alloy, or stainless steel. The thickness of the metal layer L2 is, for example, 30 μm to 60 μm.

[0085] The second resin layer L3 is laminated on the metal layer L2 on the side opposite to the resin layer L1 when viewed from the metal layer L2. Examples of materials for the second resin layer L3 include polyethylene terephthalate (PET) or nylon. The thickness of the resin layer is, for example, 20 μm to 60 μm. The second resin layer L3 may include multiple resin films made of the above materials.

[0086] As described above, an energy storage cell 10 according to one embodiment of the present disclosure comprises an electrode body 100 and a cell case 200. The cell case 200 houses the electrode body 100. The cell case 200 has a cylindrical body portion 210, a first sealing body 510, and a second sealing body 610. The cylindrical body portion 210 is formed by molding a film F into a cylindrical shape, and has a first opening 218 and a second opening 219 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 is in contact with the inner peripheral surface 210S of the cylindrical body portion 210. The outer peripheral surface 511S has a body surface portion 511Sa and a protruding portion 511Sb. The main body surface portion 511Sa extends parallel to the first direction D1, where the first opening 218 and the second opening 219 are aligned. The protruding portion 511Sb protrudes from the main body surface portion 511Sa toward the cylindrical main body portion 210.

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

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

[0089] According to the above configuration, the thickness of the resin layer L1 between the metal layer L2 and the protrusion 511Sb becomes relatively thin. This makes it possible to further reduce the moisture permeability between the metal layer L2 and the protrusion 511Sb.

[0090] Furthermore, 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 configuration, the moisture permeability between the metal layer L2 and the protrusion 511Sb can be further reduced.

[0092] Furthermore, in this embodiment, the projection 511Sb extends in an annular shape along the circumferential direction of the inner circumferential surface 210S of the cylindrical body portion 210. The hole H1 extends in an annular shape along the projection 511Sb.

[0093] According to the above configuration, the main body surface portion 511Sa and the protruding portion 511Sb form a labyrinth structure along the entire circumferential direction of the inner circumferential surface 210S. Consequently, the decrease 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 not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to 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 Intervening part, 132b First folded part, 132c Second folded part, 132d Outermost covering part, 132e Termination, 200 Cell case, 210 Cylindrical body part, 210S Inner circumferential surface, 211 Bottom surface part, 212 First side surface part, 213 Second side surface part, 214 Top surface part, 215 Strip-shaped part, 218 510 First opening, 219 Second opening, 510 First sealing body, 511 First plate-shaped part, 511S Outer surface, 511Sa Main body surface, 511Sb Protruding part, 512 First extension part, 512a, 612a Inner layer part, 512b, 612b Outer layer part, 515, 615 Pressure relief 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 part, 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 part, 611S Second outer surface, 611Sa Second main body surface, 611Sb Second protrusion, 612 Second extension, 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, FE2 Second side end, H1 Hole, H2 Second hole, L1 Resin layer, L2 Metal layer, L3 Second resin layer.

Claims

1. Electrode body and The system comprises a cell case that houses the electrode body, The aforementioned cell case is A cylindrical body portion formed by shaping a film into a tube, with a first opening and a second opening formed at each end, A first sealing body that closes the first opening, It has a second sealing body that closes the second opening, The first sealing body has an outer surface that adheres to the inner surface of the cylindrical main body, The outer circumferential surface has a main body surface portion extending parallel to the first direction in which the first opening and the second opening are aligned, and a projection portion that protrudes from the main body surface portion toward the cylindrical main body portion. The film comprises a resin layer constituting the inner circumferential surface of the cylindrical body portion and a metal layer laminated on the resin layer. The resin layer has a hole that fits with the protruding portion, thus forming an energy storage cell.

2. The aforementioned holes penetrate the resin layer, The energy storage cell according to claim 1, wherein the protruding portion is in contact with the metal layer through the hole.

3. The aforementioned protrusion extends in an annular shape along the circumferential direction of the inner surface of the cylindrical main body, The energy storage cell according to claim 1 or claim 2, wherein the hole extends in an annular shape along the protrusion.

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