Electricity storage device and method for manufacturing the same

Abstract

An electricity storage device disclosed by the present invention is provided with: an electrode body that comprises a first electrode and a second electrode; a can that contains the electrode body, while having a bottomed cylindrical shape that is provided with an opening at one end; and a sealing body that is bonded to the one end of the can so as to seal the opening. The sealing body comprises a conductive first ring, a conductive second ring that is joined to the first ring, a conductive terminal plate that is provided between the first ring and the second ring, and an insulating ring that insulates the first ring and the second ring from the terminal plate. The outer periphery of the terminal plate is held between the first ring and the second ring by the intermediary of the insulating ring.

Description

[Technical Field]

[0001] The present disclosure relates to an electricity storage device and a method for manufacturing an electricity storage device. [Background technology]

[0002] As an example of a conventional energy storage device, a battery including a cylindrical battery can with a bottom and an opening at one end, and a battery cap that seals the opening, has been known (for example, Patent Document 1). As shown in FIG. 4 of Patent Document 1, the battery cap of the battery of Patent Document 1 includes an outer conductive ring, a conductive top plate and a conductive rupture disc that are electrically insulated from the outer conductive ring, and two insulating members for the electrical insulation. The outer conductive ring functions as a cathode, while the conductive top plate and the conductive rupture disc function as a positive electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-519078 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the battery cap of the battery in Patent Document 1 has a large number of parts and each part has a complex shape, which may increase manufacturing costs. In this situation, one of the objects of the present disclosure is to provide an electricity storage device that can be manufactured at low cost and to which external lead wires can be easily connected. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to an energy storage device including an electrode assembly having a first electrode and a second electrode, a cylindrical can that houses the electrode assembly and has a bottom and an opening at one end, and a sealing body that is joined to the one end of the can to seal the opening, the sealing body having a conductive first ring, a conductive second ring joined to the first ring, a conductive terminal plate disposed between the first ring and the second ring, and an insulating ring that insulates the terminal plate from the first ring and the second ring, and the outer periphery of the terminal plate is sandwiched between the first ring and the second ring via the insulating ring.

[0006] Another aspect of the present disclosure relates to a method for manufacturing the above-described power storage device, the method including: a first step of placing the insulating ring and the terminal plate on one of the first ring and the second ring; a second step of pressing the insulating ring with the other of the first ring and the second ring to sandwich the outer periphery of the terminal plate between the insulating ring and compress the insulating ring; a third step of joining the first ring and the second ring together while the insulating ring is compressed to obtain the sealing body; and a fourth step of joining the first ring to the one end of the can. [Effects of the Invention]

[0007] According to the present disclosure, an electricity storage device can be obtained that prevents the sealing body from becoming complicated in configuration, has low manufacturing costs, and allows for easy connection of external lead wires. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a longitudinal sectional view schematically showing a battery of Embodiment 1. FIG. [Figure 2] FIG. 2 is an enlarged end view showing a main part of the battery of the first embodiment. [Figure 3A] FIG. 2 is a diagram illustrating a first step in the method for producing the battery of the first embodiment. [Figure 3B] 4 is a diagram illustrating a second step in the method for producing the battery of the first embodiment. FIG. [Figure 3C] 4 is a diagram illustrating a third step in the method for producing the battery of the first embodiment. FIG. [Figure 3D] 10 is a diagram illustrating a fourth step in the method for producing the battery of the first embodiment. FIG. [Figure 4] FIG. 3 is an enlarged end view showing a main part of a battery according to a modified example of the first embodiment. [Figure 5] FIG. 10 is an enlarged end view showing a main part of a battery according to a second embodiment. [Figure 6A] FIG. 10 is a diagram illustrating a first step in the method for producing a battery according to the second embodiment. [Figure 6B] 10 is a diagram illustrating a second step in the method for producing a battery according to the second embodiment. FIG. [Figure 6C] 10 is a diagram illustrating a third step in the method for producing a battery according to the second embodiment. FIG. [Figure 6D] 10 is a diagram illustrating a fourth step in the method for producing a battery according to the second embodiment. FIG. [Figure 7] FIG. 10 is an enlarged end view showing a main part of a battery according to a first modification of the second embodiment. [Figure 8] FIG. 10 is an enlarged end view showing a main part of a battery according to a second modification of the second embodiment. [Figure 9] FIG. 10 is an enlarged end view showing a main part of a battery according to a third modification of the second embodiment. [Figure 10] FIG. 10 is an enlarged end view showing a main part of a battery according to a fourth modification of the second embodiment. [Figure 11] FIG. 10 is an enlarged end view showing a main part of a battery according to a fifth modification of the second embodiment. [Figure 12] FIG. 10 is an enlarged end view showing a main part of a battery according to a sixth modification of the second embodiment. [Figure 13] FIG. 10 is an enlarged end view showing a main part of a battery according to a seventh modification of the second embodiment. [Figure 14] FIG. 13 is an enlarged end view showing a main part of a battery according to Modification 8 of Embodiment 2. [Figure 15] FIG. 10 is an enlarged end view showing a main part of a battery according to a third embodiment. [Figure 16] FIG. 10 is an enlarged end view showing a main part of a battery according to a first modification of the third embodiment. [Figure 17] FIG. 10 is an enlarged end view showing a main part of a battery according to a second modification of the third embodiment. [Figure 18] FIG. 10 is an enlarged end view showing a main part of a battery according to a third modification of the third embodiment. [Figure 19] FIG. 10 is an enlarged end view showing a main part of a battery according to a fourth modification of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the power storage device of the present disclosure will be described below using an example of a battery. However, the power storage device of the present disclosure is not limited to the example described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may be applied as long as the effects of the present disclosure are obtained. Note that the power storage device of the present disclosure may also include a capacitor in addition to the battery of the following embodiment.

[0010] (Electricity storage device) The power storage device of the present disclosure includes a can and a sealing body, which will be described below.

[0011] (can) The can is a bottomed tube with an opening formed at one end. The can may have a cylindrical tube portion and a bottom portion. The tube portion may be cylindrical or rectangular. The tube portion may have an opening at one end and the other end may be closed by a bottom portion. The material of the can is not particularly limited, and may be, for example, iron, an iron alloy, copper, aluminum, or an aluminum alloy. When the can is electrically connected to the negative electrode of the electrode assembly, the can material is preferably iron or copper, and when the can is electrically connected to the positive electrode of the electrode assembly, the can material is preferably aluminum or an aluminum alloy.

[0012] (sealing body) The sealant seals an opening at one end of the can and is joined to that end. The sealant has a conductive first ring, a conductive second ring, a conductive terminal plate, and an insulating ring. The sealant also has an exposed surface that is exposed to the outside of the battery.

[0013] The first ring has a first outer diameter D1. The first ring is joined to one end of the can. The outer peripheral shape of the first ring may be, for example, circular or rectangular. The inner peripheral shape of the first ring may be, for example, circular or rectangular. The material of the first ring is not particularly limited and can be selected from the materials exemplified for the can. Furthermore, the material of the first ring may be different from the material of the can.

[0014] The second ring may have a second outer diameter D2 smaller than the first outer diameter D1. The second ring is joined to the first ring. The outer peripheral edge of the second ring may be joined to the first ring. The outer peripheral shape of the second ring may be, for example, circular or rectangular. The inner peripheral shape of the second ring may be, for example, circular or rectangular. The material of the second ring is not particularly limited and can be selected from the materials exemplified for the can. Furthermore, the material of the second ring may be different from the materials of the can and the first ring. Note that the second outer diameter D2 may be equal to the first outer diameter D1, and the outer peripheral edge of the second ring may be joined to one end of the can together with the outer peripheral edge of the first ring.

[0015] The terminal plate may have a third outer diameter D3 smaller than the second outer diameter D2. The terminal plate is housed in at least one of the first ring and the second ring. The outer peripheral edge of the terminal plate is sandwiched between the first ring and the second ring via an insulating ring. The shape of the terminal plate may be, for example, a disk or a rectangle. The material of the terminal plate is not particularly limited and can be selected from the materials exemplified for the can. When the terminal plate is electrically connected to the negative electrode of the electrode body, the material of the terminal plate is preferably iron or copper, and when the terminal plate is electrically connected to the positive electrode of the electrode body, the material of the terminal plate is preferably aluminum or an aluminum alloy.

[0016] Note that the portion of the terminal plate other than the portion sandwiched between the first ring and the second ring may extend outside the first ring or the second ring. Furthermore, as long as the portion of the terminal plate other than the portion sandwiched between the first ring and the second ring can be electrically insulated from the first ring or the second ring, the outer diameter of the portion extending outside the first ring or the second ring may be larger than the first outer diameter D1 or the second outer diameter D2.

[0017] The insulating ring electrically insulates the first and second rings from the terminal plate. The cross section of the insulating ring cut in the axial direction may be roughly U-shaped or C-shaped. The material of the insulating ring is not particularly limited as long as it has electrical insulation properties, and may be, for example, polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), or polyamide (PA).

[0018] The exposed surface is formed by the first ring or by the first ring and the second ring. The exposed surface extends from one end of the can radially inward of the can. The exposed surface is a surface exposed to the outside of the energy storage device. The exposed surface may be the outer surface of the first ring (i.e., the top surface or upper surface), or the outer surfaces of the first ring and the second ring (i.e., the top surfaces or upper surfaces). The exposed surface may have a generally ring-like shape. The inner diameter D of the exposed surface may be smaller than the third outer diameter D3 of the terminal board. An external lead wire may be connected to the exposed surface.

[0019] (Method of manufacturing an electricity storage device) The method for manufacturing an electricity storage device according to the present disclosure includes a first step, a second step, a third step, and a fourth step, which will be described below.

[0020] (1st step) In the first step, an insulating ring and a terminal plate are placed on one of the first ring and the second ring. In the first step, the cross section of the insulating ring formed by cutting it in the axial direction may be generally L-shaped. One of the first ring and the second ring may have a recess capable of accommodating at least a portion of the insulating ring and the terminal plate.

[0021] (2nd process) In the second step, the insulating ring is pressed down by the other of the first ring and the second ring, so that the outer periphery of the terminal board is sandwiched between the insulating ring and the insulating ring is compressed. The cross-sectional shape of the pressed-down insulating ring may be generally U-shaped or C-shaped.

[0022] (3rd step) In the third step, the first ring and the second ring are joined together while the insulating ring is compressed to obtain a sealing body. The first ring and the second ring may be joined together by, for example, laser welding. The first ring and the second ring may be joined together along the entire circumference of each ring, or may be joined together intermittently. The insulating ring may be held in a compressed state in a predetermined mold, or may be held in a compressed state in an apparatus that joins the two rings.

[0023] (4th step) In a fourth step, the sealing body is joined to one end of the can, thereby sealing the opening at one end of the can. The sealing body may be joined to the one end of the can by, for example, laser welding. The sealing body may be joined to the one end of the can around the entire periphery.

[0024] As described above, according to the present disclosure, the shapes of the first ring and the second ring are simplified, and an electricity storage device can be obtained that is low in manufacturing cost and to which external lead wires can be easily connected. Furthermore, workability is also improved in that steps 1 to 3 can be carried out separately from other work in step 4. Therefore, according to the present disclosure, such an electricity storage device can be easily manufactured.

[0025] The exposed surface may be formed by a first ring. In this case, the exposed surface can be made flat all over by flattening the outer surface of the first ring. Therefore, the exposed surface can be made flat more easily than when the exposed surface is made up of multiple rings.

[0026] The exposed surface may be formed by a first ring and a second ring.

[0027] The first ring may have a first recess into which the second ring fits. This allows the first ring and the second ring to be easily aligned when they are joined. At this time, the outer periphery of the second ring and the inner periphery of the first recess of the first ring may be welded together. This joining method allows the first ring and the second ring to be joined without penetrating each other.

[0028] A second recess for accommodating at least a portion of the insulating ring may be formed on the surface of the second ring facing the first ring. This configuration facilitates alignment of the insulating ring with the second ring. Furthermore, the second recess of the second ring may have a curved or sloped surface at the connection (inner corner) between the inner bottom surface and the inner side surface. This configuration facilitates bending the side wall of the insulating ring accommodated in the second recess of the second ring so as to tilt radially inward.

[0029] A recess or notch may be formed in the peripheral side surface of at least one of the first ring and the second ring at a position axially spaced from the joint between the sealing body and one end of the can and / or the joint between the first ring and the second ring. Alternatively or in addition, a recess or notch may be formed in the top or bottom surface of at least one of the first ring and the second ring at a position radially spaced from the joint between the sealing body and one end of the can and / or the joint between the first ring and the second ring. These recesses or notches make it more difficult for heat to be transferred to a region of the sealing body radially inward of the recess or notch, thereby suppressing the effects of heat on the insulating ring.

[0030] At least one of the first ring and the second ring may have a protrusion that protrudes toward the insulating ring in the axial direction of the can, whereby the protrusion compresses the insulating ring more strongly, thereby improving the airtightness of the electricity storage device.

[0031] The first ring and the second ring may have protrusions, which increases the number of points on the insulating ring that are strongly compressed, thereby further improving the airtightness of the electricity storage device.

[0032] The protrusions of the first ring and the second ring may be aligned (facing each other) in the axial direction, which makes it easier to apply a compressive force to the insulating ring, further improving the airtightness of the energy storage device.

[0033] The fourth step may be performed after the first, second, and third steps, which allows the second step of pressing down the insulating ring and the third step of joining the first and second rings to be performed without the can being located nearby, thereby improving workability and reliability.

[0034] In the third step, the first ring and the second ring may be joined together with a heat dissipation member (cooling member) in contact with at least one of the first ring and the second ring. This allows at least a portion of the heat generated by the joining to be absorbed by the heat dissipation member. This reduces the thermal impact on the insulating ring. This makes it possible to prevent damage to the insulating ring due to heat. The heat dissipation member may be, for example, a metal body or a member with a larger heat capacity than the first ring or the second ring.

[0035] The heat dissipation member may be in contact with at least one of the first and second rings in an area closer to the outer periphery than the joint between the first and second rings, thereby further reducing the thermal impact on the insulating ring located closer to the inner periphery than the joint area.

[0036] Below, examples of a power storage device and a manufacturing method thereof according to the present disclosure will be specifically described with reference to the drawings. The components and steps of the manufacturing method of the power storage device in the example described below can be applied to the components and steps described above. The components and steps of the manufacturing method of the power storage device in the example described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiment. Of the components and steps of the manufacturing method of the power storage device in the example described below, components that are not essential for the power storage device and manufacturing method thereof according to the present disclosure may be omitted.

[0037] First Embodiment The following description will first explain the battery according to this embodiment, followed by a description of a manufacturing method for the battery according to this embodiment. In the following description, the upper side of each figure will be referred to as the "upper side" and the lower side of each figure as the "lower side," but this is for convenience and does not limit the present disclosure. In the following description, the axial direction of the battery can (in other words, the direction in which the bottom of the battery can faces the sealing body) will be referred to as the "axial direction," and the radial direction of the battery can will be referred to as the "radial direction." In addition, if the battery can is rectangular rather than cylindrical, the radial direction may be interpreted as a direction perpendicular to the central axis of the cylindrical portion.

[0038] (battery) As shown in FIGS. 1 and 2, a battery 10, which is an example of an electricity storage device, includes a battery can 20, which is an example of a can, an electrode assembly 40, and a sealing assembly 30.

[0039] The battery can 20 is a cylindrical body with a bottom, and has an opening at one end (top end). The battery can 20 has a cylindrical portion 21 that houses the electrode body 40, and a bottom portion 22 that closes the bottom end of the cylindrical portion 21. The cylindrical portion 21 is formed in a cylindrical shape. The bottom portion 22 is formed in a disk shape.

[0040] The electrode assembly 40 is a wound type, and is configured by spirally winding a positive electrode (first electrode) and a negative electrode (second electrode) with a separator interposed therebetween. An internal lead wire 50 is connected to one of the positive electrode and the negative electrode. The internal lead wire 50 is joined by welding or the like to the underside of a terminal plate 33, which will be described later. Another lead wire (not shown) is connected to the other of the positive electrode and the negative electrode. The other lead wire is joined by welding or the like to the inner surface of the battery can 20. The electrode assembly 40 is accommodated in the battery can 20 together with an electrolyte (not shown). The electrolyte may contain a non-aqueous solvent and an electrolyte, and may be in a gel or solid form.

[0041] The sealing body 30 is a structure that seals the opening at one end of the battery can 20. The sealing body 30 has a conductive first ring 31, a conductive second ring 32, a conductive terminal plate 33, and an insulating ring 34. The sealing body 30 further has an exposed surface 35 that is exposed to the outside of the battery 10.

[0042] The first ring 31 has a first outer diameter D1. The first ring 31 is joined at its outer periphery to one end of the battery can 20 by, for example, laser welding. A cross-sectional shape of the first ring 31 cut in the axial direction is stepped, with the inner and outer diameters decreasing toward the bottom of the battery can 20. This stepped inner surface forms part of a first recess 31a and a second recess 31b, which will be described later. On the lower axial side (electrode body side), the opening of the first ring 31 is located radially inward of the outer periphery of the terminal plate 33. Note that the opening of the first ring 31 can be interpreted as including the first recess 31a, the second recess 31b, and the through-hole formed in the bottom of the second recess 31b.

[0043] The first ring 31 has a downwardly recessed first recess 31a. The inner diameter of the first recess 31a is substantially the same as or slightly smaller than the second outer diameter D2 of the second ring 32. The depth of the first recess 31a is substantially equal to the thickness (vertical length) of the second ring 32. The second ring 32 fits into the first recess 31a. Note that a portion of the second ring 32 may protrude from the first recess 31a. Furthermore, the second ring 32 may be considered to include a third recess 32a (described below) and a through-hole formed in the bottom of the third recess 32a as an opening of the second ring 32.

[0044] First ring 31 has second recess 31b recessed downward in the bottom surface of first recess 31a. The inner diameter of second recess 31b is larger than third outer diameter D3 of terminal plate 33. Second recess 31b accommodates insulating ring 34 and at least a portion of terminal plate 33.

[0045] The second ring 32 has a second outer diameter D2 smaller than the first outer diameter D1. The outer peripheral edge of the second ring 32 and the open end of the first recess 31a of the first ring 31 (in other words, the upper end opening of the first ring) are joined by, for example, laser welding. The inner peripheral end (opening end) of the second ring 32 is located radially inward of the outer peripheral end of the terminal plate 33. The radial position of the inner peripheral end (opening end) of the second ring 32 may be substantially the same as the radial position of the inner peripheral end of the first ring 31. In other words, the inner peripheral ends of the second ring 32 and the first ring 31 may be aligned (facing each other) in the axial direction. Note that the inner peripheral ends of the first ring 31 and the second ring 32 may be offset from each other in the radial direction.

[0046] The second ring 32 has a third recess 32a recessed upward. The inner diameter of the third recess 32a is substantially equal to the inner diameter of the second recess 31b of the first ring 31. The bottom corners of the third recess 32a (connection points between the inner bottom surface and the inner circumferential surface of the third recess 32a) are rounded. A part of the insulating ring 34 is housed in the third recess 32a. The inner diameters of the second recess 31b and the third recess 32a may be different from each other.

[0047] Terminal plate 33 has a third outer diameter D3 smaller than second outer diameter D2. Terminal plate 33 is formed in a substantially circular plate shape. The outer peripheral edge of terminal plate 33 is sandwiched between the inner peripheral edges of first ring 31 and second ring 32 via insulating ring 34. An external lead wire (not shown) can be connected to the upper surface of terminal plate 33.

[0048] The insulating ring 34 electrically insulates the first ring 31 and the second ring 32 from the terminal plate 33. The cross-sectional shape of the insulating ring 34 is substantially U-shaped or C-shaped. The insulating ring 34 may extend to cover the upper end of the opening of the second ring 32, or may extend to cover the lower end of the opening of the first ring 31. This configuration can improve the reliability of the electrical insulation between the first ring 31 and the second ring 32 and the terminal plate 33.

[0049] The exposed surface 35 is formed by the first ring 31 and the second ring 32. More specifically, a portion of the exposed surface 35 is formed by the upper surface of the first ring 31 that is closer to the outer periphery than the first recess 31a. The remaining portion of the exposed surface 35 is formed by the upper surface of the second ring 32.

[0050] The exposed surface 35 extends radially inward from one end of the battery can 20. The inner peripheral edge of the exposed surface 35 is located radially inward of the outer peripheral edge of the terminal plate 33. In top view, the exposed surface 35 may cover more than half of the insulating ring 34, or may cover less than half of the insulating ring 34. A separate external lead wire (not shown) can be joined to the exposed surface 35.

[0051] In the battery 10 configured as described above, the first ring 31 and the second ring 32 function as one of the positive and negative terminals, and the terminal plate 33 functions as the other of the positive and negative terminals. Therefore, current can be collected from the positive and negative electrodes from one side (top side) of the battery 10.

[0052] (Battery manufacturing method) 3A to 3D, the battery manufacturing method includes a first step, a second step, a third step, and a fourth step. In this embodiment, the first step, the second step, the third step, and the fourth step are performed in the order shown. However, the order in which the steps are performed is not limited to this.

[0053] In the first step, the insulating ring 34 and the terminal plate 33 are placed on the first ring 31. At this time, the insulating ring 34 and the terminal plate 33 are at least partially housed in the second recess 31b of the first ring 31.

[0054] In the second step, the second ring 32 presses down on the insulating ring 34, sandwiching the outer periphery of the terminal board 33 between the insulating ring 34 and compressing the insulating ring 34. At this time, because the bottom corners of the third recess 32a of the second ring 32 are rounded, the insulating ring 34 can be guided by the rounded portions and bent so as to fall radially inward.

[0055] In the third step, the first ring 31 and the second ring 32 are joined together while the insulating ring 34 is compressed, to obtain the sealing body 30. At this time, the first ring 31 and the second ring 32 are preferably joined together over the entire circumferential direction of the first ring 31 and the second ring 32 by laser welding using a laser L. Alternatively, the first ring 31 and the second ring 32 may be joined together with a heat exhaust member (not shown) in contact with the first ring 31 in a region closer to the outer periphery than the joint between the first ring 31 and the second ring 32.

[0056] In a fourth step, the first ring 31 of the sealing body 30 is joined to one end of the battery can 20 that houses the electrode assembly 40. At this time, it is preferable to join the first ring 31 to one end of the battery can 20 around the entire circumference by laser welding using a laser L. Between the third and fourth steps, the following steps may be performed: connecting one end of an internal lead wire that connects to the positive electrode of the electrode assembly 40 to the positive electrode; connecting one end of an internal lead wire that connects to the negative electrode of the electrode assembly 40 to the negative electrode; joining the other end of one of the two internal lead wires to the inner surface of the bottom of the battery can 20; joining the other end of the other of the two internal lead wires to the lower surface of the terminal plate 33; and housing the electrode assembly 40 and an electrolyte in the battery can 20.

[0057] <<Modification of the First Embodiment>> A modified example of the first embodiment will be described. This modified example differs from the first embodiment in that the first ring 31 and the second ring 32 have protrusions 31c and 32b. The following mainly describes the differences from the first embodiment.

[0058] 4, the first ring 31 has a protrusion 31c that protrudes in the axial direction toward the insulating ring 34. This protrusion 31c is provided on the surface of the first ring 31 that faces the insulating ring 34. It is preferable that the protrusion 31c extends in an annular shape on the surface that faces the insulating ring 34.

[0059] The second ring 32 has a protrusion 32b that protrudes in the axial direction toward the insulating ring 34. This protrusion 32b is provided on the surface of the second ring 32 that faces the insulating ring 34. It is preferable that the protrusion 32b extends in an annular shape on the surface that faces the insulating ring 34.

[0060] The protrusion 31c of the first ring 31 and the protrusion 32b of the second ring 32 are aligned in the axial direction of the battery can 20. In other words, the radial position of the protrusion 31c of the first ring 31 may be substantially the same as the radial position of the protrusion 32b of the second ring 32. With this configuration, the protrusions 31c and 32b can compress the insulating ring 34 more strongly.

[0061] Second Embodiment A second embodiment will be described. This embodiment differs from the first embodiment in that the exposed surface 35 is formed only by the first ring 31. The following mainly describes the differences from the first embodiment.

[0062] (battery) As shown in FIG. 5, the first ring 31 of this embodiment has a shape that fills the space between the first ring 31 and the battery can 20 in the first embodiment. The first ring 31 does not have a stepped outer peripheral surface, but has an outer peripheral surface with an axial length equal to the axial length of the sealing body 30. The first ring 31 is solid from the outer peripheral surface to the inner peripheral surface. A first recess 31a is formed on the lower surface of the first ring 31 (the surface facing the electrode body 40), and a second recess 31b is formed on the bottom surface of the first recess 31a. A third recess 32a is formed on the upper surface of the second ring 32 (the surface facing the first ring 31). The first ring 31 covers at least a portion of the insulating ring 34 from above. The terminal plate 33 and the insulating ring 34 are disposed in the gap between the second recess 31b and the third recess 32a. As in the first embodiment, the outer peripheral edge of terminal board 33 is sandwiched between second recess 31b and third recess 32a via insulating ring .

[0063] The first ring 31 and the second ring 32 are joined to each other on the lower surface side (electrode body 40 side) of the sealing body 30. The exposed surface 35 is formed only by the first ring 31. Specifically, the exposed surface 35 is formed by the upper surface of the first ring 31.

[0064] (Battery manufacturing method) As shown in FIGS. 6A to 6D, the method for manufacturing a battery includes a first step, a second step, a third step, and a fourth step.

[0065] Steps 1 to 3 of this embodiment are substantially the same as steps 1 to 3 of the above-described embodiment 1. Here, in this embodiment, the volume of the first ring 31 is larger than that of the above-described embodiment 1, which has the advantage that the thermal influence of the joining in the third step is less likely to affect the insulating ring 34.

[0066] In a fourth step, the sealing body 30 obtained in the third step is turned upside down, and then the first ring 31 is joined to one end of the battery can 20. Because the joint in the third step is located inside the battery 10, the exposed surface 35 can be easily made flat by making the top surface of the first ring 31 flat.

[0067] First Modification of Second Embodiment A first modification of the second embodiment will be described. This modification differs from the second embodiment in the radial length of the second ring 32. The following mainly describes the differences from the second embodiment.

[0068] 7, the radial length of the second ring 32 in this modification is longer than that in the second embodiment. In other words, the inner diameter of the first recess 31a of the first ring 31 in this modification is larger than that in the second embodiment. With this configuration, the joint between the first ring 31 and the second ring 32 is located farther from the insulating ring 34, making the insulating ring 34 less susceptible to the effects of heat from the joint. This improves the reliability of the battery 10.

[0069] <<Modification 2 of Embodiment 2>> Modification 2 of Embodiment 2 will be described. This modification differs from Embodiment 2 above in the axial length of the second ring 32. The following mainly describes the differences from Embodiment 2 above.

[0070] As shown in Fig. 8, the axial length of the portion of the second ring 32 of this modification that is closer to the outer periphery than the insulating ring 34 is longer than that of the second embodiment. Furthermore, the first ring 31 has a first recess 31a into which the second ring 32 fits, but does not have a second recess 31b into which the insulating ring 34 and at least a portion of the terminal board 33 are housed. With this configuration, the volume of the second ring 32 is increased compared to the second ring 32 of the second embodiment, and the heat capacity of the second ring 32 is increased. Therefore, the influence of heat from the joint between the first ring 31 and the second ring 32 on the insulating ring 34 can be suppressed more effectively than the second ring 32 of the second embodiment.

[0071] Third Modification of Second Embodiment Modification 3 of Embodiment 2 will be described. This modification differs from Embodiment 2 above in the dimensions of the second ring 32. The following mainly describes the differences from Embodiment 2 above.

[0072] As shown in FIG. 9 , the radial length of the second ring 32 of this modification is longer than that of the second embodiment. The axial length of the second ring 32 of this modification is longer than that of the second embodiment. The first ring 31 has a first recess 31a into which the second ring 32 fits, but does not have a second recess 31b into which the insulating ring 34 and at least a portion of the terminal board 33 are accommodated. The second ring 32 of this modification has a larger volume than the second ring 32 of the first and second modifications of the second embodiment. Therefore, compared to the second ring 32 of the first and second modifications of the second embodiment, the influence of heat from the joint between the first ring 31 and the second ring 32 on the insulating ring 34 can be suppressed.

[0073] Fourth Modification of Second Embodiment A fourth modification of the second embodiment will be described. This modification differs from the second embodiment in the shape of the first ring 31. The following mainly describes the differences from the second embodiment.

[0074] As shown in FIG. 10 , the first ring 31 of this modification has a shape similar to that of the first ring 31 of the second embodiment, with a portion of the outer periphery closer to the bottom removed (cut out). In other words, the first ring 31 of this modification has a fourth recess 31d (cutout) in a region closer to the outer periphery (a region closer to the outer periphery of the first ring 31 and inside the battery can 20, axially spaced from the joint between the sealing body 30 and the battery can 20). This makes the sealing body 30 of this modification lighter than the sealing body 30 of the second embodiment. Furthermore, the fourth recess 31d reduces the cross-sectional area of ​​the path of heat transfer from the joint between the sealing body 30 and the battery can 20 to the radially inner side of the sealing body 30. Therefore, heat is less likely to be transferred to a region of the sealing body 30 that is radially inner than the fourth recess 31d.

[0075] Fifth Modification of Second Embodiment Modification 5 of Embodiment 2 will be described. This modification differs from Modification 1 of Embodiment 2 above in the shape of the first ring 31. The following mainly describes the differences from Modification 1 of Embodiment 2 above.

[0076] As shown in FIG. 11 , the first ring 31 of this modification has a shape similar to that of the first ring 31 of Modification 1 of Embodiment 2, with the central portion near the outer periphery removed. In other words, the first ring 31 of this modification has a fourth recess 31d in an axially central region of the outer periphery (a region of the outer periphery between both axial ends, axially separated from the joint between the sealing body 30 and the battery can 20). This makes the sealing body 30 of this modification lighter than the sealing body 30 of Modification 1 of Embodiment 2. Furthermore, the fourth recess 31d reduces the cross-sectional area of ​​the path of heat transfer from the joint between the sealing body 30 and the battery can 20 to the radially inner side of the sealing body 30. Therefore, heat is less likely to be transferred to the region of the sealing body 30 that is radially inner than the fourth recess 31d.

[0077] Sixth Modification of Second Embodiment A sixth modification of the second embodiment will be described. This modification differs from the second modification of the second embodiment in the shape of the first ring 31. The following mainly describes the differences from the second modification of the second embodiment.

[0078] As shown in FIG. 12 , the first ring 31 of this modification has a shape similar to that of the first ring 31 of Modification 2 of Embodiment 2, with a portion of the outer periphery closer to the lower side removed (cut away). In other words, the first ring 31 of this modification has a fourth recess 31d in a region of the outer periphery closer to the lower end (a region of the outer periphery on the electrode assembly 40 side, axially spaced from the joint between the sealing body 30 and the battery can 20). This makes the sealing body 30 of this modification lighter than the sealing body 30 of Modification 2 of Embodiment 2. Furthermore, the fourth recess 31d reduces the cross-sectional area of ​​the path of heat transfer from the joint between the sealing body 30 and the battery can 20 to the radially inner side of the sealing body 30. Therefore, heat is less likely to be transferred to the region of the sealing body 30 that is radially inner than the fourth recess 31d.

[0079] Seventh Modification of Second Embodiment A seventh modification of the second embodiment will be described. This modification differs from the third modification of the second embodiment in the shape of the second ring 32. The following mainly describes the differences from the third modification of the second embodiment.

[0080] As shown in FIG. 13 , the second ring 32 of this modification has an annular groove shape similar to that of the second ring 32 of Modification 3 of Embodiment 2, hollowed out from the bottom. In other words, the second ring 32 of this modification has a fifth recess 32c that is radially spaced from the joint between the first ring 31 and the second ring 32 and opens toward the inside of the battery can 20. This makes the sealing body 30 of this modification lighter than the sealing body 30 of Modification 3 of Embodiment 2. Furthermore, the fifth recess 32c reduces the cross-sectional area of ​​the path of heat that transfers from the joint between the first ring 31 and the second ring 32 to the radially inner side of the sealing body 30. Therefore, heat is less likely to transfer to a region of the sealing body 30 that is radially inward of the fifth recess 32c.

[0081] Eighth Modification of Second Embodiment Modification 8 of Embodiment 2 will be described. This modification differs from Modification 3 of Embodiment 2 above in the shape of the second ring 32. The following mainly describes the differences from Modification 3 of Embodiment 2 above.

[0082] As shown in FIG. 14 , the second ring 32 of this modification has an annular groove shape similar to that of the second ring 32 of Modification 3 of Embodiment 2 described above, hollowed out from the upper side. In other words, the second ring 32 of this modification has a fifth recess 32c that is radially spaced from the joint between the first ring 31 and the second ring 32, opens toward the outside of the battery can 20, and is blocked by the first ring 31. This makes the sealing body 30 of this modification lighter than the sealing body 30 of Modification 3 of Embodiment 2 described above. Furthermore, the fifth recess 32c reduces the cross-sectional area of ​​the path of heat that conducts from the joint between the first ring 31 and the second ring 32 to the radially inner side of the sealing body 30. Therefore, heat is less likely to be conducted to a region of the sealing body 30 that is radially inward of the fifth recess 32c.

[0083] Third Embodiment A third embodiment will be described. This embodiment differs from the first embodiment in that the exposed surface 35 is formed only by the first ring 31. The following mainly describes the differences from the first embodiment.

[0084] 15, the first ring 31 is an annular member with flat upper and lower surfaces. The upper surface of the first ring 31 is an exposed surface 35. The second ring 32 has a third recess 32a that accommodates the insulating ring 34 and at least a portion of the terminal plate 33.

[0085] The first ring 31 and the second ring 32 are joined to each other by, for example, full penetration welding using a laser L. In this embodiment, the first ring 31 and the second ring 32 are joined by full penetration welding from the first ring 31 side (upper side). This configuration makes it possible to simplify the shape of the first ring 31. In addition, the shape of the second ring 32 can also be simplified.

[0086] First Modification of Third Embodiment A first modification of the third embodiment will be described. This modification differs from the third embodiment in the manner in which the first ring 31 and the second ring 32 are joined. The following mainly describes the differences from the third embodiment.

[0087] As shown in FIG. 16, in this embodiment, the first ring 31 and the second ring 32 are joined by full penetration welding from the second ring 32 side (the lower side or the electrode body 40 side).

[0088] <<Modification 2 of Embodiment 3>> Modification 2 of Embodiment 3 will be described. This modification differs from the above-described Embodiment 3 in that the first ring 31 and the second ring 32 are provided with positioning structures. The following mainly describes the differences from the above-described Embodiment 3.

[0089] As shown in FIG. 17 , the first ring 31 has a positioning recess 31e formed on its underside. Meanwhile, the second ring 32 has a positioning protrusion 32d that protrudes upward and fits into the positioning recess 31e. Therefore, when manufacturing the battery 10 of this modification, the first ring 31 and the second ring 32 can be easily positioned relative to each other in the second and third steps. The first ring 31 and the second ring 32 are joined to each other in the areas where the positioning recess 31e and the positioning protrusion 32d are provided. This configuration allows the first ring 31 and the second ring 32 to be easily aligned.

[0090] Third Modification of Third Embodiment Modification 3 of Embodiment 3 will be described. This modification differs from Embodiment 3 in that the first ring 31 and the second ring 32 are provided with positioning structures. The following mainly describes the differences from Embodiment 3.

[0091] As shown in FIG. 18 , the second ring 32 has an annular positioning recess 32e formed on its upper surface. Meanwhile, the first ring 31 has an annular positioning protrusion 31f that protrudes downward and fits into the positioning recess 32e. Therefore, when manufacturing the battery 10 of this modification, the first ring 31 and the second ring 32 can be easily positioned relative to each other in the second and third steps. The first ring 31 and the second ring 32 are joined to each other in the areas where the positioning recess 32e and the positioning protrusion 31f are provided. With this configuration, as with the second modification of the third embodiment, the first ring 31 and the second ring 32 can be easily aligned.

[0092] Fourth Modification of the Third Embodiment Modification 4 of Embodiment 3 will be described. This modification differs from the above-described Embodiment 3 in that the first ring 31 has a positioning structure. The following mainly describes the differences from the above-described Embodiment 3.

[0093] As shown in FIG. 19 , a positioning protrusion 31f that protrudes downward is provided on the underside of the first ring 31. The inner diameter of the positioning protrusion 31f is substantially equal to or slightly smaller than the outer diameter (second outer diameter D2) of the second ring 32. The second ring 32 fits into the annular positioning protrusion 31f. Therefore, when manufacturing the battery 10 of this modified example, the first ring 31 and the second ring 32 can be easily positioned relative to each other in the second and third steps. The inner peripheral edge of the positioning protrusion 31f of the first ring 31 and the outer peripheral edge of the second ring 32 are joined to each other.

[0094] It goes without saying that the sealing body 30 described so far in embodiments 1 to 3 (including each of the modified examples) may be joined to one end of the battery can 20 with the top and bottom surfaces inverted from the described configuration, provided that the flatness of the exposed surface 35 is not taken into consideration. [Industrial Applicability]

[0095] The present disclosure can be used in an electricity storage device and a method for manufacturing an electricity storage device. [Explanation of symbols]

[0096] 10: Battery (power storage device) 20: Battery can 21:Cylinder part 22: Bottom 30: Sealing body 31: First Ring 31a: First recess 31b: Second recess 31c:Protrusion 31d: 4th recess 31e: Positioning recess 31f: Positioning protrusion 32: Second Ring 32a: Third recess 32b:Protrusion 32c: 5th recess 32d: Positioning protrusion 32e: Positioning recess 33:Terminal board 34: Insulation ring 35: Exposed surface 40: Electrode body 50: Internal lead wire D: Inner diameter of exposed surface D1: 1st outer diameter D2: 2nd outer diameter D3: Third outer diameter L: Laser

Claims

1. an electrode assembly having a first electrode and a second electrode; a can that accommodates the electrode assembly and has a bottomed cylindrical shape and an opening at one end; a sealing body joined to the one end of the can to seal the opening, The sealing body is a conductive first ring; a conductive second ring joined to the first ring; a conductive terminal plate provided between the first ring and the second ring; an insulating ring that insulates the first ring, the second ring, and the terminal plate, an outer peripheral edge of the terminal board is sandwiched between the first ring and the second ring via the insulating ring; The first ring has a first recess into which the second ring fits.

2. the first ring has a first outer diameter D1; the second ring has a second outer diameter D2 that is smaller than the first outer diameter D1; the terminal plate has a third outer diameter D3 smaller than the second outer diameter D2, The electricity storage device according to claim 1 , wherein the first ring is joined to the one end of the can.

3. 3. The energy storage device according to claim 2, wherein the sealing body is formed by the first ring or by the first ring and the second ring, and has an exposed surface that extends from the one end of the can toward a radially inner side of the can.

4. The power storage device according to claim 3 , wherein an outer circumferential edge of the second ring and an inner circumferential edge of the first recess are welded together.

5. a second recess for accommodating at least a portion of the insulating ring is formed on a surface of the second ring facing the first ring, The power storage device according to claim 4 , wherein a connecting portion between an inner bottom surface and an inner side surface of the second recess is a curved surface or an inclined surface.

6. 6. The energy storage device according to claim 1, wherein a recess or a notch is formed on a side peripheral surface of at least one of the first ring and the second ring at a position spaced apart in the axial direction of the can from at least one of a joint between the sealing body and the one end of the can and a joint between the first ring and the second ring.

7. 7. The energy storage device according to claim 1, wherein a recess or a notch is formed on an upper surface or a lower surface of at least one of the first ring and the second ring at a position radially spaced apart from at least one of a joint between the sealing body and the one end of the can and a joint between the first ring and the second ring.

8. 8. The power storage device according to claim 1, wherein at least one of the first ring and the second ring has a protrusion that protrudes toward the insulating ring in the axial direction of the can.

9. The power storage device according to claim 8 , wherein the first ring and the second ring have the protrusion.

10. The power storage device according to claim 9 , wherein the protruding portion of the first ring and the protruding portion of the second ring are aligned in the axial direction.

11. A method for manufacturing the electricity storage device according to any one of claims 1 to 10, a first step of placing the insulating ring and the terminal plate on one of the first ring and the second ring; a second step of pressing the insulating ring with the other of the first ring and the second ring to sandwich the outer periphery of the terminal board between the insulating ring and compress the insulating ring; a third step of joining the first ring and the second ring together while the insulating ring is compressed to obtain the sealing body; a fourth step of joining the sealing body to the one end of the can; A method for manufacturing an electricity storage device, comprising:

12. The method for manufacturing an electricity storage device according to claim 11 , wherein the fourth step is performed after the first step, the second step, and the third step.

13. 13. The method for manufacturing an energy storage device according to claim 11, wherein in the third step, the first ring and the second ring are joined to each other in a state where a heat exhaust member is in contact with at least one of the first ring and the second ring.

14. The method for manufacturing an electric storage device according to claim 13 , wherein the heat dissipation member is brought into contact with at least one of the first ring and the second ring in an area closer to an outer periphery than a joint between the first ring and the second ring.

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