Power storage element and method for manufacturing power storage element

Abstract

Provided is a power storage element comprising: a cylindrical case body in which openings are formed at both ends; an electrode body housed in the case body; a spacer disposed between the case body and the electrode body; and a tape wound around the electrode body and the spacer. The spacer has a protrusion protruding from an outer edge of the tape when viewed from a first direction from one opening to the other opening, and the protrusion is provided between the tape and the one opening in the first direction.

Description

Electric energy storage element and method for manufacturing an electric energy storage element

[0001] The present invention relates to an electric energy storage element and a method for manufacturing an electric energy storage element. This application claims priority based on Japanese Patent Application No. 2024-215468 filed in Japan on December 10, 2024, and incorporates the content thereof herein.

[0002] For example, Patent Document 1 discloses an electric energy storage element provided with a spacer. In the electric energy storage element disclosed in Patent Document 1, the spacer is located between a rectangular ceiling portion and a current collector member. Such a spacer maintains the distance between the current collector member and the ceiling portion.

[0003] Japanese Patent No. 5849623 Gazette

[0004] The electric energy storage element may include a case body having openings formed at both ends and an electrode body housed in the case body. When manufacturing such an electric energy storage element, the electrode body and the spacer are fixed outside the case body using a tape, and the electrode body and the spacer together with the tape are inserted into the case body through the openings. At this time, if the tape rubs against the case body, a part of the tape may peel off.

[0005] The present invention has been made in view of the above-described problems, and an object thereof is to prevent the tape from peeling off in an electric energy storage element in which an electrode body and a spacer are fixed with a tape.

[0006] As a means for solving the above problems, each aspect of the present invention has the following configuration. The electric energy storage element according to the first aspect of the present invention includes a cylindrical case body having openings formed at both ends, an electrode body housed in the case body, a spacer located between the case body and the electrode body, and a tape wound around the electrode body and the spacer. The spacer has a protrusion protruding from the outer edge of the tape when viewed from a first direction which is a direction from one of the openings to the other opening, and the protrusion is provided between the tape and the one opening in the first direction.

[0007] In a method for manufacturing an energy storage element according to a second aspect of the present invention, the energy storage element comprises a cylindrical case body having openings formed at both ends, an electrode body housed in the case body, a spacer positioned between the case body and the electrode body, and a tape wrapped around the electrode body and the spacer, wherein the spacer has a projection that protrudes from the outer edge of the tape when viewed from a first direction which is from one opening to the other opening, and the electrode body and the spacer are inserted into the case body from the other opening toward the one opening such that the projection is positioned between the tape and the one opening in the first direction.

[0008] According to an aspect of the present invention, in an energy storage element in which an electrode body and a spacer are fixed with tape, it is possible to prevent the tape from peeling off.

[0009] This is a perspective view of the energy storage element according to the first embodiment. This is a partially exploded perspective view of the energy storage element according to the first embodiment. This is an exploded view of part III in Figure 2. This is a cross-sectional view along the line IV-IV in Figure 1. This is a perspective view of the spacer of the energy storage element according to the first embodiment. This is a cross-sectional view along line V-V in Figure 5. This is a schematic diagram showing a method for manufacturing the energy storage element according to the first embodiment. This is a view of the spacer of the energy storage element according to the second embodiment, seen from the Y direction. This is a view of the end of the spacer of the energy storage element according to the second embodiment, seen from the Z direction. This is a perspective view of a modified example of the spacer.

[0010] (1) A first aspect of the present invention provides an energy storage element comprising a cylindrical case body having openings formed at both ends, an electrode body housed in the case body, a spacer positioned between the case body and the electrode body, and a tape wrapped around the electrode body and the spacer, wherein the spacer has a projection that protrudes from the outer edge of the tape when viewed from a first direction which is from one opening to the other opening, and the projection is provided between the tape and one of the openings in the first direction.

[0011] In the energy storage element described in (1) above, the electrode body and the spacer are fixed by wrapping tape around them. The spacer is provided with a projection that protrudes from the outer edge of the tape when viewed from a first direction from one opening of the case body toward the other opening. Inside the case body, this projection is located between one opening and the tape in the first direction. Therefore, when the electrode body and spacer are fixed with tape outside the case body, and the electrode body and spacer together with the tape are inserted into the case body from the other opening toward the first opening, the projection rubs against the case body, preventing the tape from rubbing against the case body. Thus, the energy storage element described in (1) above can prevent the tape from peeling off in an energy storage element in which the electrode body and spacer are fixed with tape.

[0012] (2) In the energy storage element described in (1) above, the spacer has a corner when viewed from the first direction, the tape is arranged to cover the corner, and the projection may be provided on the corner.

[0013] According to the energy storage element described in (2) above, the spacer has corners, and tape is provided so as to cover the corners of the spacer. The corners of the spacer are areas that are prone to rubbing against the case body. The energy storage element described in (2) above has protrusions provided on these corners of the spacer. Therefore, the energy storage element described in (2) above can prevent the tape from peeling off even if the spacer has corners that are prone to rubbing against the case body.

[0014] (3) In the energy storage element described in (1) or (2) above, the spacer has a shape in which the end is further away from the electrode body than the central part in a cross section perpendicular to the first direction, and the protrusion may be provided at the end.

[0015] According to the energy storage element described in (3) above, the spacer is formed in a shape such that, in a cross section perpendicular to the first direction, its ends are further away from the electrode body than the central part. The ends of such a spacer are parts that are prone to rubbing against the case body. The energy storage element described in (3) above has a projection at the end of this spacer. Therefore, even if the spacer has ends that are prone to rubbing against the case body, the energy storage element described in (3) above can prevent the tape from peeling off.

[0016] (4) In a method for manufacturing an energy storage element according to a second aspect of the present invention, the energy storage element comprises a cylindrical case body having openings formed at both ends, an electrode body housed in the case body, a spacer positioned between the case body and the electrode body, and a tape wrapped around the electrode body and the spacer, wherein the spacer has a projection that protrudes from the outer edge of the tape when viewed from a first direction which is from one opening to the other opening, and the electrode body and the spacer are inserted into the case body from the other opening toward the one opening such that the projection is positioned between the tape and the one opening in the first direction.

[0017] According to the method for manufacturing an energy storage element described in (4) above of the present invention, the electrode body and the spacer are fixed by wrapping tape around them. The spacer is provided with a projection that protrudes from the outer edge of the tape when viewed from a first direction from one opening of the case body toward the other opening. When inserting the electrode body and the spacer into the case body, the electrode body and the spacer are inserted integrally into the case body such that the projection is positioned between one opening and the tape in the first direction. As a result, the projection rubs against the case body, preventing the tape from rubbing against the case body. Therefore, the method for manufacturing an energy storage element described in (4) above can prevent the tape from peeling off.

[0018] [Embodiment] (First Embodiment) Next, a first embodiment of the present invention will be described based on the drawings.

[0019] <Energy Storage Element> Figure 1 is a perspective view of the energy storage element 1. Figure 2 is a partially exploded perspective view of the energy storage element 1. Figure 3 is an exploded view of part III in Figure 2. Figure 4 is a cross-sectional view along the line IV-IV in Figure 1. The energy storage element 1 is a secondary battery (single cell) that can charge and discharge electricity. More specifically, the energy storage element 1 is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 1 is used as a battery for driving mobile vehicles such as automobiles, motorcycles, and railway vehicles for electric railways, for starting engines, etc.

[0020] The above-mentioned vehicles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. In addition, the energy storage element 1 can also be used as a stationary battery for household or commercial use.

[0021] The energy storage element 1 is not limited to a non-aqueous electrolyte secondary battery. The energy storage element 1 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or it may be a capacitor. The energy storage element 1 may be a primary battery instead of a secondary battery. The energy storage element 1 may be a battery using a solid electrolyte.

[0022] As shown in Figures 1 to 3, the energy storage element 1 mainly consists of two electrode bodies 2, a case 3 that houses each electrode body 2, positive and negative terminals 4 and a current collector 5 provided on the case 3, and leads 6 that connect the electrode bodies 2 and the current collector 5. Each electrode body 2 is formed in a flat rectangular parallelepiped shape (with an oval cross-section) and is arranged overlapping in the thickness direction. In the following description, the thickness direction (overlapping direction) of the electrode bodies 2 will be referred to as the X direction. The longitudinal direction of the electrode body 2 as viewed from the thickness direction will be referred to as the Y direction. The direction perpendicular to the X and Y directions will be referred to as the Z direction. In addition, the direction facing the center of the electrode body 2 in the Y direction may be referred to as the inside of the Y direction, and the direction opposite to the inside of the Y direction may be referred to as the outside of the Y direction.

[0023] <Electrode Body> The electrode body 2 is an energy storage element (power generation element) that can store electricity. The electrode body 2 comprises a positive electrode plate, a negative electrode plate, and a separator (neither of which is shown in the figure) placed between the positive electrode plate and the negative electrode plate. The positive electrode plate is an electrode plate on which a positive electrode active material layer is formed on a positive electrode current collector foil. The positive electrode current collector foil is a long, strip-shaped current collector foil made of aluminum or an aluminum alloy. The negative electrode plate is an electrode plate on which a negative electrode active material layer is formed on a negative electrode current collector foil. The negative electrode current collector foil is a long, strip-shaped current collector foil made of copper or a copper alloy.

[0024] As the current collector foil, nickel, copper, or other appropriately known materials can be used. As the positive electrode active material and negative electrode active material mentioned above, any active material capable of intercalating and deintercalating lithium ions can be used, as appropriate known materials. For the separator, for example, a microporous sheet or nonwoven fabric made of resin can be used.

[0025] Under this configuration, the electrode body 2 is formed by winding a positive electrode plate, a negative electrode plate, and a separator together with the Y direction as the central axis. In other words, the electrode body 2 is a so-called wound-type electrode body. The positive electrode plate and the negative electrode plate have portions where the current collector foil is exposed without an active material layer being formed, as these portions are drawn out separately from both ends in the Y direction. By stacking and bundling these portions, the tabs 7 for the positive and negative electrodes are formed. Thus, the tabs 7 for the positive electrode and the tabs 7 for the negative electrode in the electrode body 2 are drawn out separately from both sides in the Y direction. In this embodiment, two such electrode bodies 2 are arranged stacked in the X direction.

[0026] Furthermore, as shown in Figure 2, the electrode body 2 is formed in a rectangular shape having a pair of short sides 2a and a pair of long sides 2b when viewed from the Y direction (first direction). Each short side 2a extends linearly along the X direction. The two short sides 2a are arranged in the Z direction and are parallel to each other. Each long side 2b extends linearly along the Z direction. The two long sides 2b are arranged in the X direction and are parallel to each other. Each long side 2b connects one short side 2a to the other short side 2a. In other words, each long side 2b connects the short sides 2a to each other.

[0027] <Case> Case 3 comprises a cylindrical case body 8 having openings 8a at both ends in the Y direction, and two lids 9 that close the two openings 8a. The case body 8 and lids 9 are formed from a weldable metal such as stainless steel, aluminum, or aluminum alloy. However, they are not limited to this, and the case body 8 and lids 9 can also be formed from resin.

[0028] The case body 8 is formed in a flat rectangular parallelepiped shape with a thin thickness in the X direction to correspond to the shape of the electrode body 2. The electrode body 2 is housed inside the case body 8, covered with an insulating sheet 10. As for the electrolyte, there are no particular restrictions on the type as long as it does not impair the performance of the energy storage element 1, and various types can be selected.

[0029] The two lids 9 have the same basic structure. Therefore, in the following description, only one of the two lids 9 will be described, and only the differences between the two will be described. The lid 9 is a rectangular plate-like member that is long in the Z direction when viewed from the Y direction, corresponding to the shape of the opening 8a of the case body 8. The lid 9 is connected to the periphery of the opening 8a of the case body 8 by welding or the like. This seals the inside of the case body 8.

[0030] One of the two lids 9 is provided with a gas discharge valve 11 near the first end 9a in the Z direction. The gas discharge valve 11 releases pressure when the pressure inside the case body 8 rises. An electrolyte injection port 12 is provided near the second end 9b, opposite to the first end 9a of the lid 9. The electrolyte injection port 12 is used to inject electrolyte into the case body 8. A lid through-hole 13 is formed closer to the first end 9a than the electrolyte injection port 12 of the lid 9. A terminal 4 is inserted into the lid through-hole 13 via an insulator 14.

[0031] <Insulator> The insulator 14 is formed of a resin material having electrical insulating properties. Examples of this resin material include polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), and polyether sulfone (PES). The insulator 14 located on the positive electrode tab 7 side and the insulator 14 located on the negative electrode tab 7 side have the same configuration and are arranged symmetrically with respect to the electrode body 2. For this reason, in the following description, only one of the two insulators 14 will be described, and the description of the other will be omitted.

[0032] As shown in Figure 3, the insulator 14 is arranged on both sides of the lid 9 in the Z direction. That is, the insulator 14 comprises an outer insulator 15 arranged on the outer surface 9c of the lid 9 and an inner insulator 16 arranged on the inner surface 9d of the lid 9.

[0033] The outer insulator 15 has an outer base portion 17 positioned on the outer surface 9c of the lid 9. The outer base portion 17 is formed in a square shape when viewed from the Y direction. A side wall 18 is formed on the outer circumference of the outer base portion 17, rising outward in the Y direction. The side wall 18 and the outer base portion 17 form a terminal storage recess 19. A cylindrical portion 21 is formed in the center of the outer base portion 17 when viewed from the Y direction, projecting inward in the Y direction. The cylindrical portion 21 penetrates the outer base portion 17 in the Y direction. The cylindrical portion 21 is fitted into the lid through hole 13 of the lid 9. The tip of the cylindrical portion 21 and the inner surface 9d of the lid 9 are located on the same plane.

[0034] The inner insulator 16 is formed in the shape of a rectangular plate that is elongated in the Z direction when viewed from the Y direction. More specifically, the inner insulator 16, which is located on the side of the lid 9 where the gas discharge valve 11 is provided, extends from the lid through hole 13 of the lid 9 to the gas discharge valve 11. The inner insulator 16 has an inner through hole 23 formed coaxially with the lid through hole 13. The inner diameter of the inner through hole 23 is the same as the inner diameter of the cylindrical portion 21 of the outer insulator 15.

[0035] <Current Collectors> The current collectors 5 are arranged so as to overlap each other on the inner surface 16a of each inner insulator 16 in the Y direction. The two current collectors 5 are the positive electrode current collector 5 located on the positive electrode tab 7 side and the negative electrode current collector 5 located on the negative electrode tab 7 side. These current collectors 5 have the same configuration and are arranged symmetrically with respect to the electrode body 2. For this reason, in the following explanation, only one of the two current collectors 5 will be described, and the explanation of the other will be omitted.

[0036] The material of the current collector 5 is not particularly limited. However, for example, the positive electrode current collector 5 of the positive electrode current collector 5 is made of aluminum or an aluminum alloy, similar to the positive electrode current collector foil of the electrode body 2. The negative electrode current collector 5 is made of copper or a copper alloy, similar to the negative electrode current collector foil of the electrode body 2.

[0037] The current collector 5 is formed in the shape of a rectangular plate that is elongated in the Z direction when viewed from the Y direction. More specifically, the current collector 5 is formed to overlap most of the inner insulator 16. The thickness of the current collector 5 is, for example, about 1 to 3 mm.

[0038] The current collector 5 has a current collector through-hole 26 that penetrates the current collector 5. The inner diameter of the current collector through-hole 26 is the same as the inner diameter of the inner through-hole 23. The current collector 5 has protrusions 27 formed on both ends in the Z direction and on one side in the X direction. The protrusions 27 are formed in a C shape when viewed from the Y direction. These protrusions 27 are formed by pressing the current collector 5, which pushes the outer surface 5b side toward the inner surface 5a side and bends it. That is, recesses are formed on the outer surface 5b of the current collector 5 to correspond to the protrusions 27.

[0039] <Terminals> The terminals 4 are inserted through the lid through holes 13 of each lid 9 via an insulator 14. The terminals 4 provide electrical conductivity between the inside and outside of the lid 9 (case 3). The two terminals 4 are a positive terminal 4 located on the positive tab 7 side and a negative terminal 4 located on the negative tab 7 side. The positive terminal 4 is made of, for example, aluminum or an aluminum alloy. In contrast, the negative terminal 4 is made of, for example, copper or a copper alloy. These terminals 4 have the same configuration and are arranged symmetrically with respect to the electrode body 2. For this reason, in the following description, only one of the two terminals 4 will be described, and the description of the other will be omitted.

[0040] The terminal 4 comprises a shaft portion 35 and a head portion 36 integrally provided at the axial end of the shaft portion 35. The shaft portion 35 is inserted into the lid through-hole 13 of each lid 9 via an insulator 14. The diameter of the shaft portion 35 is the same as or slightly smaller than the inner diameter of the cylindrical portion 21 of the outer insulator 15. The head portion 36 is formed in a square shape when viewed from the Y direction. The size of the outer shape of the head portion 36 is such that it can be housed in the terminal housing recess 19 of the outer insulator 15.

[0041] In this configuration, the terminal 4 is inserted into the cylindrical portion 21 of the outer insulator 15, the inner through-hole 23 of the inner insulator 16, and the current collector through-hole 26 of the current collector 5, with the tip of the shaft portion 35 opposite to the head portion 36 facing the cover 9 from the outside in the Y direction. The head portion 36 is then housed in the terminal housing recess 19 of the outer insulator 15. As a result, the tip of the shaft portion 35 protrudes from the inner surface 5a of the current collector 5 through the current collector through-hole 26.

[0042] A crimped portion 37 is formed at the tip of the protruding shaft portion 35 by spin crimping. This integrates the cover 9, insulator 14, current collector 5, and terminal 4. The current collector 5 and terminal 4 are connected via the cover 9 and insulator 14. The crimped portion 37 is housed in the recess 25 of the current collector 5.

[0043] <Lead> There are a positive electrode lead 6 that electrically connects the tab 7 of the positive electrode and the terminal 4 of the positive electrode, and a negative electrode lead 6 that electrically connects the tab 7 of the negative electrode and the terminal 4 of the negative electrode. These leads 6 have the same configuration. Each lead 6 is formed in a rectangular plate shape that is long in the Z direction when viewed from the Y direction. More specifically, the length of the lead 6 in the Y direction is the same as the length of the inner insulator 16 in the Y direction. The thickness of the lead 6 is, for example, about 0.5 to 2 mm.

[0044] The material of the lead 6 is not particularly limited. However, for example, the positive electrode lead 6 among the positive electrode and negative electrode leads 6 is formed of aluminum or an aluminum alloy, etc., similar to the positive electrode current collector foil of the electrode body 2. The negative electrode lead 6 is formed of copper or a copper alloy, etc., similar to the negative electrode current collector foil of the electrode body 2.

[0045] <Insulating Sheet> The insulating sheet 10 insulates the case body 8 and the electrode body 2. The insulating sheet 10 is formed of a tape made of a resin sheet such as PP or PE, for example. The insulating sheet 10 is wound around the electrode body 2 and the two spacers 50, and fixes the electrode body 2 and the two spacers 50. The spacers 50 are located between the case body 8 and the electrode body 2. In the present embodiment, each spacer 50 is located between the case body 8 and the short side 2a of the electrode body 2 and the case body 8 when viewed from the Y direction. The insulating sheet 10 is, for example, an adhesive tape with an adhesive attached to one side, and is joined to both the electrode body 2 and the spacer 50. The electrode body 2 and the spacer 50 are fixed to each other and integrated by being adhered to the insulating sheet 10 respectively.

[0046] The insulating sheet 10 is fixed so that the spacer 50 is positioned between the short side 2a of the electrode body 2 and the case body 8, and is joined to the surface of the electrode body 2 that is orthogonal to the X direction. The surface of the electrode body 2 that is orthogonal to the X direction has a larger area than the surface orthogonal to the Z direction and the surface orthogonal to the Y direction, and is the surface having the largest area of the electrode body 2. The surface of the electrode body 2 that is orthogonal to the X direction is referred to as the maximum surface 2c of the electrode body 2. That is, in the present embodiment, the insulating sheet 10 is joined to the maximum surface 2c of the electrode body 2. The insulating sheet 10 may be formed of a single tape. Also, the insulating sheet 10 may be formed of a plurality of tapes.

[0047] The length dimension of the insulating sheet 10 in the Y direction is larger than the length dimension of the electrode body 2 in the Y direction. That is, the length in the first direction of the fixing portion is longer than the length in the first direction of the electrode body. For example, when the length dimension of the electrode body 2 in the Y direction is 200 mm, the length dimension of the insulating sheet 10 in the Y direction is larger than 200 mm.

[0048] <Spacer> The spacer 50 is positioned between the case body 8 and the electrode body 2, and fixes the position of the electrode body 2 within the case body 8. The spacer 50 has insulating properties and is formed of, for example, resin. The spacer 50 restricts the movement of the electrode body 2 with respect to the case body 8. The spacer 50 is arranged so as to contact each of the surfaces of the electrode body 2 that are orthogonal to the Z direction. The two spacers 50 are the spacer 50 that contacts one of the two surfaces of the electrode body 2 that are orthogonal to the Z direction, and the spacer 50 that contacts the other of the two surfaces of the electrode body 2 that are orthogonal to the Z direction. These spacers 50 have the same configuration and are arranged symmetrically with the electrode body 2 interposed therebetween. For this reason, in the following description, only one of the two spacers 50 will be described, and the description of the other will be omitted.

[0049] The spacer 50 is formed in a straight line so as to extend along the Y direction. The Y direction is the first direction, which is the direction from one opening 8a of the case body 8 to the other opening 8a. In other words, the spacer 50 is formed so as to extend in the first direction, which is the direction from one opening 8a of the case body 8 to the other opening 8a. The length dimension of the spacer 50 in the Y direction is greater than the length dimension of the electrode body 2 in the Y direction. For example, if the length dimension of the electrode body 2 in the Y direction is 200 mm, then the length dimension of the spacer 50 in the Y direction is greater than 200 mm. Furthermore, the length dimension of the spacer 50 in the Y direction may be greater than the length dimension of the insulating sheet 10 in the Y direction. In other words, the length of the spacer in the first direction may be longer than the length of the fixing part in the first direction. This allows the spacer 50 to be pressed while the spacer 50 and the lid 9 are in direct contact, so that the electrode body 2 can be reliably inserted into the case body 8.

[0050] Figure 5 is a perspective view of the spacer 50. The spacer 50 has a main body portion 51 and a projection 52 (protrusion). The main body portion 51 is a linearly formed portion that extends along the Y direction and is the portion to which the insulating sheet 10 is adhered. The end portion 51a of the main body portion 51 in the X direction is curved so that its tip surface faces toward the electrode body 2. Because the end portion 51a of the main body portion 51 is curved, a corner portion 51b is formed on the main body portion 51 when viewed from the Y direction. In other words, the spacer 50 has a corner portion 51b when viewed from the Y direction.

[0051] The projections 52 are provided on each of the ends 51c of the main body 51 in the Y direction. The projections 52 are protrusions that extend from the end 51c of the main body 51 toward the side opposite to the electrode body 2. The projections 52 are provided on the entire end 51c, including the corner 51b, in the X direction. In other words, the portion of the projection 52 that protrudes from the corner 51b is curved along the corner 51b when viewed from the Y direction.

[0052] Figure 6 is a cross-sectional view taken along line V-V in Figure 5. The insulating sheet 10 is positioned between the two ends 51c of the main body 51. This insulating sheet 10 is in contact with the main body 51 without overlapping the projection 52. As shown in Figure 6, the projection dimension H of the projection 52 from the main body 51 is greater than the thickness dimension of the insulating sheet 10. Therefore, the tip of the projection 52 is located further from the electrode body 2 than the outer edge 10a of the insulating sheet 10 when viewed from the Y direction. In other words, the projection 52 is formed to protrude beyond the outer edge 10a of the insulating sheet 10.

[0053] <Manufacturing Method for Energy Storage Element> Next, the manufacturing method for the energy storage element 1 will be described. First, after forming the electrode body 2, leads 6 corresponding to each tab 7 are connected in advance. As for the connection method at this time, welding such as ultrasonic connection, laser welding or resistance welding, or mechanical connection such as crimping can be used. Ultrasonic connection is preferred as the method of connecting the tab 7 and the lead 6. Subsequently, the periphery of the electrode body 2 is covered with an insulating sheet 10. The electrode body 2 is wrapped with the insulating sheet 10 together with the spacer 50. The spacer 50 is fixed to the electrode body 2 in contact with the surface of the electrode body 2 perpendicular to the Z direction.

[0054] Meanwhile, the insulators 14, current collectors 5, and terminals 4 are pre-assembled onto the two lids 9. Next, the current collector 5 assembled on one of the lids 9 is superimposed on one of the leads 6 of the spacer 50. Then, the superimposed current collector 5 and lead 6 are connected. One possible method of connection is laser welding.

[0055] Next, as shown in Figure 7, the lid 9, to which the current collector 5 connected to the lead 6 is assembled, is placed against the end face of the spacer 50, and the lid 9 is pushed with a jig or the like (not shown) to house the electrode body 2 inside the case body 8. In other words, the electrode body 2 and the spacer 50 are inserted from the other opening 8a toward the first opening 8a. Furthermore, the lid 9 that pushed the electrode body 2 is used to close the first opening 8a of the case body 8. Note that the connection between the current collector 5 and the lead 6 may be made after the electrode body 2 and spacer 50 have been housed in the case body 8.

[0056] Here, the spacer 50 has a projection 52 that protrudes beyond the outer edge 10a of the insulating sheet 10 when viewed from the Y direction. Therefore, when inserting the electrode body 2 and the spacer 50 into the case body 8, the projection 52 rubs against the case body 8, preventing the insulating sheet 10 from rubbing against the case body 8.

[0057] Next, the current collector 5 attached to the other lid 9 and the other lead 6 are superimposed. Then, the superimposed current collector 5 and lead 6 are connected. One possible method of connection is laser welding. Furthermore, this lid 9 is used to close the other opening 8a of the case body 8. After this, welding is performed around the case body 8 and the two lids 9 to seal the case 3.

[0058] Each tab 7 is bent so as to be slightly folded. Inside the case 3 are the internal insulator 16, current collector 5, lead 6, tab 7, and electrode body 2. The terminal 4 penetrates the inside and outside of the lid 9. Next, electrolyte (non-aqueous electrolyte) is poured into the case body 8 through the liquid injection port 12 of the lid 9. This completes the manufacturing of the energy storage element 1.

[0059] <Function and Effects> As described above, the energy storage element 1 of this embodiment comprises a case body 8, an electrode body 2, a spacer 50, and an insulating sheet 10. The case body 8 is formed in a cylindrical shape with openings 8a formed at both ends. The electrode body 2 is housed in the case body 8. The spacer 50 is located between the case body 8 and the electrode body 2. The insulating sheet 10 is wrapped around the electrode body 2 and the spacer 50. The spacer 50 has a projection 52 that protrudes from the outer edge 10a of the insulating sheet 10 when viewed from the Y direction, which is the direction from one opening 8a to the other opening 8a. The projection 52 is provided between the insulating sheet 10 and one of the openings 8a in the Y direction.

[0060] In this embodiment of the energy storage element 1, the electrode body 2 and the spacer 50 are fixed together by wrapping an insulating sheet 10 around them. The spacer 50 is provided with a projection 52 that protrudes from the outer edge 10a of the insulating sheet 10 when viewed from the Y direction, from one opening 8a of the case body 8 toward the other opening 8a. Inside the case body 8, this projection 52 is located between one opening 8a and the insulating sheet 10 in the Y direction. Therefore, when the electrode body 2 and the spacer 50 are fixed together with the insulating sheet 10 outside the case body 8, and the electrode body 2 and the spacer 50 are inserted into the case body 8 together with the insulating sheet 10 from the other opening 8a toward the one opening 8a, the projection 52 rubs against the case body 8, preventing the insulating sheet 10 from rubbing against the case body 8. Thus, in this embodiment of the energy storage element 1, where the electrode body 2 and the spacer 50 are fixed together with the insulating sheet 10, it is possible to prevent the insulating sheet 10 from peeling off.

[0061] Furthermore, in the energy storage element 1 of this embodiment, the spacer 50 has a corner portion 51b when viewed from the Y direction. The insulating sheet 10 is arranged to cover the corner portion 51b. The projection 52 is provided on the corner portion 51b.

[0062] In this embodiment of the energy storage element 1, the spacer 50 has a corner portion 51b, and an insulating sheet 10 is provided so as to cover the corner portion 51b of the spacer 50. The corner portion 51b of the spacer 50 is a part that is prone to rubbing against the case body 8. In this embodiment of the energy storage element 1, a projection 52 is provided on the corner portion 51b of the spacer 50. Therefore, even if the spacer 50 has a corner portion 51b that is prone to rubbing against the case body 8, the insulating sheet 10 can be prevented from peeling off.

[0063] In the manufacturing method of the energy storage element 1 of this embodiment, the electrode body 2 and spacer 50 are inserted into the case body 8 from the other opening 8a toward the one opening 8a such that the projection 52 is positioned between the insulating sheet 10 and one opening 8a in the Y direction.

[0064] In the manufacturing method of the energy storage element 1 of this embodiment, the electrode body 2 and the spacer 50 are fixed together by wrapping an insulating sheet 10 around them. The spacer 50 is provided with a projection 52 that protrudes from the outer edge 10a of the insulating sheet 10 when viewed from the Y direction, from one opening 8a of the case body 8 toward the other opening 8a. When inserting the electrode body 2 and the spacer 50 into the case body 8, the electrode body 2 and the spacer 50 are inserted integrally into the case body 8 such that the projection 52 is positioned between one opening 8a and the insulating sheet 10 in the Y direction. As a result, the projection 52 rubs against the case body 8, preventing the insulating sheet 10 from rubbing against the case body 8. Therefore, the manufacturing method of the energy storage element 1 of this embodiment can prevent the insulating sheet 10 from peeling off.

[0065] (Second Embodiment) Next, a second embodiment of the present invention will be described based on the drawings. In the description of this embodiment, parts that are the same as those of the first embodiment described above will be omitted or simplified.

[0066] Figure 8 is a view of the spacer 60 of the energy storage element of this embodiment, as seen from the Y direction. Figure 9 is a view of one end of the spacer 60 in the Y direction, as seen from the Z direction. Similar to the spacer 50 of the first embodiment, two spacers 60 are provided. Each spacer 60 is located between the electrode body 2 and the case body 8 and is fixed to the electrode body 2 by an insulating sheet 10. Since the shapes of the two spacers 60 are identical, the explanation of only one spacer 60 will be given with reference to Figures 8 and 9, and the explanation of the other spacer 60 will be omitted.

[0067] As shown in Figure 8, the spacer 60 is formed such that, in a cross-section perpendicular to the Y direction (X-Z cross-section), the end portion 61 is further away from the electrode body 2 than the central portion 62. In addition, the spacer 60 is curved between the end portion 61 and the central portion 62.

[0068] As shown in Figure 9, the spacer 60 has projections 64 provided at its Y-direction end 63. The projections 64 are provided for each of the X-direction end 61 and protrude from the end 61 toward the side opposite to the electrode body 2. The insulating sheet 10 is in contact with the spacer 60 without covering the projections 64. Therefore, the projections 64 protrude beyond the outer edge 10a of the insulating sheet 10 toward the side opposite to the electrode body 2.

[0069] In this embodiment of the energy storage element, when the electrode body 2 and spacer 60, together with the insulating sheet 10, are inserted into the case body 8 from the other opening 8a toward the one opening 8a, the projection 64 rubs against the case body 8, preventing the insulating sheet 10 from rubbing against the case body 8. Therefore, the energy storage element of this embodiment can prevent the insulating sheet 10 from peeling off.

[0070] Furthermore, in the energy storage element of this embodiment, the spacer 60 is formed such that, in a cross-section perpendicular to the Y direction, the end portion 61 is further away from the electrode body 2 than the central portion 62. The end portion 61 of such a spacer 60 is a part that is prone to rubbing against the case body 8. In the energy storage element of this embodiment, a projection 64 is provided on the end portion 61 of the spacer 60. Therefore, even if the spacer 60 has an end portion 61 that is prone to rubbing against the case body 8, it is possible to prevent the insulating sheet 10 from peeling off.

[0071] [Modifications] The present invention is not limited to the embodiments described above, and includes various modifications to the embodiments described above, without departing from the spirit of the present invention.

[0072] Figure 10 is a perspective view showing a modified example of the spacer 50. As shown in this figure, the spacer 50 may have a projection 53 extending in the Y direction from the center of the main body 51 in the X direction. The projection 53 is formed from one end to the other end of the main body 51 in the Y direction. In such a case, the projection 52 is formed to protrude from the projection 53 as well.

[0073] For example, the above-described embodiment described a configuration in which two spacers 50 are provided. However, the present invention is not limited thereto. The number of spacers 50 may be changed.

[0074] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries.

[0075] 1...Energy storage element 2...Electrode body 3...Case 8...Case body 8a...Opening 10...Insulating sheet (tape) 10a...Outer edge 50...Spacer 51...Main body part 51a...End part 51b...Corner part 51c...End part 52...Protrusion 53...Protruding part 60...Spacer 61...End part 62...Center part 63...End part 64...Protrusion

Claims

1. An energy storage element comprising: a cylindrical case body with openings formed at both ends; an electrode body housed in the case body; a spacer positioned between the case body and the electrode body; and a tape wrapped around the electrode body and the spacer, wherein the spacer has a projection that protrudes from the outer edge of the tape when viewed from a first direction which is from one opening to the other opening, and the projection is provided between the tape and the one opening in the first direction.

2. The energy storage element according to claim 1, wherein the spacer has a corner when viewed from the first direction, the tape is arranged to cover the corner, and the projection is provided on the corner.

3. The energy storage element according to claim 1 or 2, wherein the spacer has a shape in which, in a cross section perpendicular to the first direction, the end portion is further away from the electrode body than the central portion, and the projection is provided at the end portion.

4. A method for manufacturing an energy storage element, comprising: a cylindrical case body with openings formed at both ends; an electrode body housed in the case body; a spacer positioned between the case body and the electrode body; and a tape wrapped around the electrode body and the spacer, wherein the spacer has a projection that protrudes from the outer edge of the tape when viewed from a first direction which is from one of the openings to the other opening, and the electrode body and the spacer are inserted into the case body from the other opening toward the one opening such that the projection is positioned between the tape and the one opening in the first direction,

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