Sealing body and battery

Abstract

This battery comprises: a case having a cylindrical section, a bottom part for closing one end section of the cylindrical section, and an opening edge section continuous to the other end section of the cylindrical section; an electrode body accommodated in the cylindrical section; and a sealing body fixed to the opening edge so as to seal the opening of the opening edge section, the battery using the sealing body which has a sealing plate composed of a first metal and a terminal member which is held by the sealing plate and is composed of a second metal different from the first metal. The sealing plate has: a fixed section to which the terminal member is fixed; an annular circumferential edge section positioned at the circumferential edge; and a thin wall section formed between the fixed section and the circumferential edge section. The fixed section has a protruding portion protruding from an outer surface of the sealing plate, and the protruding portion is bent inward so that a portion of the terminal member is sandwiched between the fixed section and the protruding section.

Description

[Technical field]

[0001] The present disclosure relates to a battery including an electrode assembly and a battery can that houses the electrode assembly. [Background technology]

[0002] A battery usually has a battery can and an electrode assembly housed in the battery can. The battery can has an opening edge, and the opening of the opening edge is sealed with a sealing body.

[0003] For example, in Patent Document 1, the sealing body is provided with a metal dish-shaped lid case, a thin plate-shaped safety valve, and a metal lid cap, which are stacked in this order from the inside to the outside of the battery can to form a sealing lid. The sealing lid is crimped onto the open end of the battery can via an insulating gasket to seal the battery can. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-90892 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the laminated body of the lid case, the safety valve, and the lid cap is sandwiched between the open end of the battery can and crimped via an insulating gasket, which increases the height of the crimped portion of the battery, which may reduce the energy density of the battery. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to a sealing body comprising: a sealing plate made of a first metal; and a terminal member made of a second metal different from the first metal and held by the sealing plate, wherein the sealing plate has a fixing portion to which the terminal member is fixed, a ring-shaped peripheral portion located on a periphery, and a thin-walled portion formed between the fixing portion and the peripheral portion, the fixing portion having a protrusion protruding from an outer surface of the sealing plate, and the protrusion is bent inwardly so that a portion of the terminal member is sandwiched between the fixing portion and the protrusion.

[0007] Another aspect of the present disclosure relates to a battery comprising: a case having a cylindrical portion, a bottom portion closing one end of the cylindrical portion, and an opening edge portion continuous with the other end of the cylindrical portion; an electrode body contained in the cylindrical portion; and the above-mentioned sealing body, wherein the sealing body is fixed to the opening edge portion so as to seal the opening of the opening edge portion. Effect of the Invention

[0008] According to the present disclosure, it is possible to prevent the peripheral edge of the sealing body from becoming a laminate, and therefore, even when a terminal member is provided, the height of the crimped portion of the battery can be prevented from increasing, and the energy density can be easily increased. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic vertical cross-sectional view of a main portion of a battery according to an embodiment of the present disclosure. [Diagram 2] 2 is an enlarged cross-sectional view of a main part of the sealing plate shown in FIG. 1, showing an engagement portion between a protrusion of the sealing plate and a flange of the terminal member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The sealing body according to this embodiment includes a sealing plate containing a first metal, and a terminal member containing a second metal different from the first metal and held by the sealing plate. The sealing plate has a fixing portion to which the terminal member is fixed, a ring-shaped peripheral portion located on the periphery, and a thin portion formed between the fixing portion and the peripheral portion. The fixing portion has a protrusion protruding from the outer surface of the sealing plate. The protrusion is bent inward so that a part of the terminal member is sandwiched between the fixing portion and the protrusion.

[0011] A sealing body is used in a battery to seal an opening of a case that houses an electrode assembly. In the sealing body, a sealing plate is electrically connected to one electrode (e.g., a positive electrode) of the electrode assembly. When the battery is installed, the sealing plate is also electrically connected to a current collecting member such as an external lead wire, and an electrical connection is made between one electrode of the electrode assembly and the external lead wire via the sealing plate. The sealing plate and the external lead wire are joined by, for example, welding.

[0012] As the first metal constituting the sealing plate, for example, aluminum or an aluminum alloy can be preferably used because it is lightweight and has excellent corrosion resistance. However, a sealing plate containing aluminum is not easily welded to a current collecting member made of a metal other than aluminum, and it is difficult to form a good joint by welding. For this reason, there is a demand for the connection between the current collecting member and the sealing body to be made of a metal material (for example, a material containing iron) that is easy to weld.

[0013] For this purpose, it is possible to adopt the configuration of Patent Document 1 and use an iron lid cap to overlap the lid case, safety valve, and lid cap and seal them by crimping. However, in this case, since the opening edge of the laminated members is crimped to seal the opening, a certain height (thickness) is required for the crimping part, and if one tries to maintain the battery at a constant height, the height of the electrode body is limited by the height of the crimping part. Conversely, if one tries to maintain the height of the electrode body, the height of the battery will increase. For this reason, it is difficult to realize a battery with a high energy density.

[0014] Furthermore, in the configuration described in Patent Document 1, three types of members, the lid case, the safety valve, and the lid cap, are overlapped and sealed with a gasket, so there are many interfaces between the members, which makes it easy for airtightness to decrease.

[0015] In contrast, according to the present embodiment, even if the sealing plate and the terminal member are made of different materials, a good electrical connection can be maintained between them. Meanwhile, the electrical connection with the current collecting member can be made via the terminal member fixed to the sealing plate. The material of the terminal member may be any material that is easy to connect with the current collecting member, and may be a material containing iron. This allows a good electrical connection to be realized between the sealing body and the external lead wire regardless of the metal material constituting the sealing plate. The current collecting member has a function of electrically connecting multiple batteries together, or a function of connecting the battery to an external electronic device or electronic circuit. This current collecting member may be a lead wire or a metal plate having welded portions at both ends.

[0016] In addition, since the opening of the case can be sealed by, for example, crimping the edge of the opening to a sealing plate via a gasket, the height of the crimped portion does not increase due to the terminal member, and thus a battery with high energy density can be easily realized.

[0017] In addition, by avoiding the peripheral portion of the sealing body being a laminate of materials, the number of interfaces between materials in the crimped portion that can be passageways for gas and moisture is reduced compared to a configuration in which the peripheral portion is a laminate of materials, thereby improving the reliability of the sealing of the battery.

[0018] The sealing plate has a fixing portion, and a protrusion protruding from the outer surface of the sealing plate is provided at the fixing portion. The protrusion is bent and extends inward (i.e., toward the inner circumference of the cylindrical portion of the battery after sealing) after being planted from the outer surface of the sealing plate, and a part of the end of the terminal member is sandwiched between the fixing portion and the protrusion. As a result, the terminal member and the sealing plate are engaged and electrically connected, and the terminal member is fixed to the sealing plate. In addition, the protrusion is bent in a direction away from the thin portion of the sealing plate to engage with the terminal member. Therefore, when the protrusion is bent, it is possible to suppress a part of the fixing portion escaping toward the thin portion, which causes a change in the thickness of the thin portion.

[0019] The protrusion is bent, for example, by applying a force to the protrusion using a mold or the like. At this time, a force in the bending direction is also applied to the portion of the protrusion located on the base side of the bending position. This may cause the base portion to deform, and the thickness of the sealing plate on the bending direction side may vary. Therefore, if there is a thin-walled portion on the bending direction side of the planting position of the protrusion, there is a risk that the thickness of the thin-walled portion will vary. In contrast, by bending the protrusion in a direction away from the thin-walled portion, it is possible to suppress deviation in the thickness of the thin-walled portion.

[0020] Specifically, the fixed portion is a portion of the sealing plate that is expected to come into contact with the terminal member and an area in the vicinity thereof. It is also a region that is thicker than the thin portion and has the thin portion formed therearound. The protrusion may be formed in an annular (or cylindrical) shape in the fixed portion, or may be provided intermittently in the circumferential direction. By connecting the terminal member at the fixed portion, the thin portion is less likely to be hindered from being displaced, compared to a configuration in which the terminal member is disposed to cover the thin portion. In other words, it is no longer necessary to design the terminal member (particularly the top plate portion) to be spaced apart from the thin portion by a certain distance in the height direction, taking into account the area in which the thin portion is displaced when the pressure inside the case increases, and the terminal member can be prevented from becoming larger.

[0021] The terminal member has, for example, a top plate portion, a side wall portion that bends and extends from the periphery of the top plate portion toward the sealing plate, and a flange portion. The flange portion is connected to the side wall portion and extends outward in a plane direction parallel to the top plate portion, for example. By having the side wall portion and the flange portion, the terminal member can suppress the thermal energy generated when the top plate portion is welded to the current collecting member from being transmitted to the inside of the battery. The side wall portion may be bent and extended over the entire circumference of the top plate portion. In this case, the terminal member may be cap-shaped. The top plate portion corresponds to the lid portion of the cap, and the side wall portion corresponds to the side wall portion of the cap. The side wall portion may be intermittently arranged in the circumferential direction from the top plate portion. The terminal member may be a disk without the side wall portion or the flange portion. In this case, the protrusion portion bends toward the periphery of the terminal member that is a disk.

[0022] The flange portion extends from the end of the side wall portion on the sealing plate side in a direction away from the top plate portion (i.e., in the direction of the outer periphery of the cylindrical portion in the battery after sealing). The flange portion may protrude in a direction away from the top plate portion over the entire circumference of the end of the side wall portion, or may protrude in a direction away from the top plate portion at a part of the entire circumference of the end of the side wall portion. The flange portion may be bent from the end of the side wall portion and extend from the top plate portion, or may be erected on the outer periphery of the side wall portion. The flange portion may be plate-shaped, and in particular, when it is provided partially, not entirely, on the side wall portion, it may be a columnar or cone-shaped protrusion. In addition, when the flange portion is plate-shaped, a recess formed by a step or a slope may be formed on the outer periphery of the flange portion, and a part of the protrusion bent toward the terminal member may be accommodated in this recess. With this configuration, the connection space between the terminal member and the protrusion can be reduced. In addition, when the flange portion is plate-shaped, the end faces of the flange portion connected to the main faces located at both ends in the thickness direction may be inclined, and the protrusions may be bent so as to be inclined along the inclination of the end faces. With this configuration, the end faces of the flange portion and the protrusions can be electrically connected to each other.

[0023] The flange portion is sandwiched between the protrusion of the sealing plate and the outer surface of the sealing plate facing the protrusion, and is fixed in a state of close contact with the sealing plate by pressing. Furthermore, a joint by welding may be formed between the protrusion and the flange portion to strengthen the close contact. The joint by welding may be a joint by laser welding. Laser welding may be performed by irradiating a laser from the outer surface of the protrusion and performing a full-through welding. In this case, if the thickness of the flange portion is thinner than the thickness of the side wall portion, it is easy to perform the full-through welding. Note that full-through welding is not necessarily required, and if the protrusion covers the upper surface of the flange portion (the back side of the surface of the flange portion facing the fixing portion), the protrusion and the flange portion may be only joined by welding.

[0024] A battery with high energy density can be realized by using the above-mentioned sealing body. The battery according to this embodiment includes a case having a cylindrical portion, a bottom portion closing one end of the cylindrical portion, and an opening edge portion continuing to the other end of the cylindrical portion, an electrode body housed in the cylindrical portion, and the above-mentioned sealing body. The sealing body is fixed to the opening edge portion so as to seal the opening of the opening edge portion.

[0025] In the following, the direction from the sealing body to the electrode body is referred to as the down direction, and the direction from the electrode body to the sealing body is referred to as the up direction. In general, when the case is stood upright with the bottom facing down, the direction parallel to the axis of the tubular part toward the opening edge is the up direction. In the following, the length in the up-down direction may be referred to as the height.

[0026] The opening of the case can be sealed, for example, by disposing a gasket on the peripheral edge of the sealing plate and crimping the opening edge to the peripheral edge of the sealing plate via the gasket. For example, an annular groove is formed on the outer peripheral surface of the cylindrical portion so that the inner peripheral surface of the cylindrical portion protrudes inwardly of the cylindrical portion, and the opening edge is bent on the opening side of the groove. The opening edge can be bent so that the gasket and the sealing plate are sandwiched between the opening edge and the groove, thereby sealing the gap between the sealing body and the opening edge. In other words, the sealing body and the opening edge can be sealed by sandwiching a sealing body including a gasket between the groove and the opening edge. In this case, the terminal member is not used for sealing, so the height of the electrode body is not limited by the terminal member, and this does not hinder the realization of a battery with a high energy density.

[0027] Hereinafter, a sealing body and a battery according to an embodiment of the present disclosure will be specifically described with reference to the drawings, but the present invention is not limited thereto.

[0028] 1 is a schematic vertical cross-sectional view of a main portion of a battery 10 including a sealing body 130 according to the present embodiment. The battery 10 has a cylindrical shape and includes a cylindrical, bottomed case 110, a cylindrical electrode assembly 120 housed in a can, and a sealing body 130 that seals the opening of the case 110.

[0029] The case 110 has a cylindrical portion 111 that houses the electrode body 120, a bottom portion 112 that closes one end of the cylindrical portion 111, and an opening edge portion 113 that is continuous with the other end of the cylindrical portion 111. The opening of the opening edge portion 113 is closed by a sealing body 130.

[0030] The sealing body 130 has a sealing plate 131 and a gasket 133 arranged on a peripheral portion 131B of the sealing plate 131. The sealing plate 131 may be disk-shaped and has an explosion-proof function. Specifically, the sealing plate 131 is provided in a central region and includes a thick fixing portion 131A and a peripheral portion 131B for ensuring structural strength, and a thin portion 131C that exerts an explosion-proof function. The thin portion 131C is provided in a region between the peripheral portion 131B and the fixing portion 131A. The peripheral portion 131B and the thin portion 131C are formed in an annular shape so as to surround the fixing portion 131A, for example.

[0031] The sealing body 130 further includes a terminal member 135. The terminal member 135 engages with the sealing plate 131 at a fixing portion 131A and is held by the sealing plate 131.

[0032] The terminal member 135 is, for example, in the form of a cap having a top plate portion 135A and a side wall portion 135B that bends and extends from the periphery of the top plate portion 135A toward the sealing plate 131. In the terminal member 135, a flange portion 135C bends from the end of the side wall portion 135B on the sealing plate 131 side toward the outer periphery of the tube portion 111 and extends away from the top plate portion 135A.

[0033] The fixing portion 131A is provided with a protrusion 131D that protrudes from the outer surface of the sealing plate 131. The protrusion 131D is bent in the inner circumferential direction of the tube portion 111 and engages with a flange portion 135C of the terminal member 135. This causes the terminal member 135 to be fixed to and electrically connected to the sealing plate 131. The protrusion 131D and the flange portion 135C may be formed over the entire circumference of the side wall portion 135B, or may be formed intermittently in a portion of the circumference of the side wall portion 135B.

[0034] The sealing plate 131 is made of a first metal. The first metal may be, for example, a metal containing aluminum. The metal containing aluminum may be, for example, metallic aluminum or an aluminum alloy. In contrast, the terminal member 135 is made of a second metal different from the first metal constituting the sealing plate 131. The second metal may be, for example, a metal containing at least one of iron and nickel. The metal containing iron may be, for example, iron or an iron alloy. As the iron alloy, stainless steel may be used. As the second metal, iron or an iron alloy plated with nickel or the like may be used.

[0035] In order to strengthen the fixation and electrical connection, a joint may be formed by welding at the engagement portion between the protrusion 131D and the flange portion 135C. For example, welding may be performed by irradiating the outer surface of the protrusion 131D covering the flange portion 135C with a laser beam from the top plate portion 135A side to perform a full penetration welding. The welding may be performed at one location on the circumference of the side wall portion 135B, or at multiple locations.

[0036] 2 is an enlarged cross-sectional view showing an engagement portion between the sealing plate 131 and the terminal member 135 in FIG. 1. Between the protrusion 131D and the flange portion 135C, a weld mark 170 is formed by full penetration welding. The weld mark 170 can be formed to a depth that penetrates the flange portion 135C and exceeds the outer surface of the sealing plate 131 (fixing portion 131A) that faces the protrusion 131D across the flange portion 135C. In order to facilitate the formation of a welded joint to a depth that penetrates the flange portion 135C, the thickness D2 of the flange portion 135C in the terminal member 135 may be made thinner than the thickness D1 of the side wall portion 135B.

[0037] The sealing plate 131 is also in contact with the terminal plate 160 at the inner surface of the fixing portion 131A (the surface facing the electrode body 120). The terminal plate 160 has a central region 160A, a peripheral portion 160B, and a thin portion 160C provided between the central region 160A and the peripheral portion 160B. The central region 160A of the terminal plate 160 is in contact with the fixing portion 131A of the sealing plate 131. The central region 160A of the terminal plate 160 and the fixing portion 131A of the sealing plate 131 may be welded to each other.

[0038] Meanwhile, the peripheral portion 160B of the terminal plate 160 is connected to an end of the internal lead 122 derived from the positive electrode or negative electrode constituting the electrode body 120. This allows the sealing plate 131 (and the terminal member 135) to have one terminal function. By connecting the current collecting member 302 to the terminal member 135, electrical connection with one electrode (first electrode) of the electrode body 120 can be made.

[0039] An insulating member 150 is interposed between peripheral portion 160B of terminal plate 160 and fixed portion 131A of sealing plate 131. Insulating member 150 may be formed integrally with gasket 133. In the battery of the present disclosure, terminal plate 160 and insulating member 150 are not essential. Internal lead 122 may be directly connected to fixed portion 131A.

[0040] A groove 114 having an inner diameter smaller than the inner diameter of the cylindrical portion of opening edge 113 and the inner diameter of cylindrical portion 111 is provided between cylindrical portion 111 and opening edge 113 of case 110. In other words, opening edge 113 is continuous with cylindrical portion 111 via groove 114.

[0041] The sealing body 130 is disposed above the groove 114 (the side away from the electrode body 120), and the opening edge 113 is bent so as to sandwich the sealing body 130 (sealing plate 131 and gasket 133) disposed above the groove 114. This causes the gasket 133 to be pressed vertically, sealing the battery 10. The repulsive force of the gasket due to the pressure ensures the airtightness of the battery 10.

[0042] An internal insulating plate 140 may be disposed below the groove portion 114 (on the electrode body 120 side) to prevent contact between the electrode body 120 and the sealing body 130 and terminal plate 160. A predetermined lead hole 141 is provided in the internal insulating plate 140. An internal lead 122 extending from one electrode constituting the electrode body 120 passes through the lead hole 141 and connects to the terminal plate 160, and is electrically connected to the sealing body 130. Meanwhile, the other electrode (second electrode) constituting the electrode body 120 is electrically connected to the case 110.

[0043] In the sealing body 130, the sealing plate 131 and the gasket 133 may be integrally molded by, for example, insert molding.

[0044] The material of the gasket 133 is not particularly limited, but for example, materials that are easy to mold into a single piece include polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), and polyamide (PA).

[0045] In the battery 10 of this embodiment, when the internal pressure rises, an outward pressure is applied to the sealing body 130 and the terminal plate 160. This pushes the sealing plate 131 and the terminal plate 160 outward. When the internal pressure exceeds a predetermined value, first, the thin portion 160C of the terminal plate 160 breaks, and the central region 160A and the peripheral portion 160B are electrically separated. As a result, the electrical connection between the sealing plate 131 and the internal lead 122 is cut off, and the current flowing through the battery 10 is interrupted.

[0046] If the internal pressure of the battery 10 does not decrease even when the current is interrupted, for example, stress due to tension is concentrated at the boundary between the peripheral portion 131B and the thin portion 131C of the sealing plate 131, causing breakage at the boundary. As a result, the internal pressure of the battery 10 is released, and the safety of the battery 10 is ensured. Note that the above current interrupt mechanism does not limit the present invention. The present invention can be applied to both batteries with and without a current interrupt mechanism. The configuration of the current interrupt mechanism is also not limited to the specific example above, and any configuration may be adopted.

[0047] In the above embodiment, the terminal member 135 is cap-shaped, but it does not necessarily have to be cap-shaped. In the terminal member 135, the side wall portion 135B may be bent and extend around the entire circumference of the top plate portion 135A, or a side wall portion may not be provided on a part of the circumference of the top plate portion 135A. Since the terminal member 135 is not used for sealing, even if there is an area on a part of the circumference of the top plate portion 135A where the side wall portion 135B (and the flange portion 135C) is not provided, this does not affect airtightness.

[0048] In the above embodiment, the groove 114 is provided in the cylindrical portion 111 of the case 110 for sealing, but the present invention is not limited to the groove. The terminal member of the present disclosure is not limited to batteries manufactured by the above sealing method, and can also be preferably used in cases where a conventional sealing method that does not provide a groove is adopted.

[0049] Examples of sealing methods that do not provide a groove include sealing by welding and pressing the side wall of the gasket in the radial direction of the opening (toward the axis of the cylindrical part) through the opening edge of the case. In these cases, by not providing a groove, the height of the electrode body can be increased by the width (height) of the groove, making it possible to further increase the capacity.

[0050] Next, the configuration of the electrode body 120 will be described by way of example using a lithium ion secondary battery. The cylindrical electrode body 120 is a wound type, and is configured by winding a positive electrode and a negative electrode in a spiral shape with a separator interposed between them. An internal lead 122 is connected to one of the positive electrode and the negative electrode. The internal lead 122 is electrically connected to a fixed portion 131A of a sealing plate 131. Another lead wire is connected to the other of the positive electrode and the negative electrode, and the other lead wire is connected to the inner surface of the case 110 by welding or the like.

[0051] (Negative electrode) The negative electrode has a strip-shaped negative electrode collector and a negative electrode active material layer formed on both sides of the negative electrode collector. A metal film, a metal foil, or the like is used for the negative electrode collector. The material of the negative electrode collector is preferably at least one selected from the group consisting of copper, nickel, titanium, alloys thereof, and stainless steel. The thickness of the negative electrode collector is preferably, for example, 5 to 30 μm.

[0052] The negative electrode active material layer contains a negative electrode active material, and optionally contains a binder and a conductive agent. The negative electrode active material layer may be a deposition film formed by a gas phase method (e.g., vapor deposition). Examples of the negative electrode active material include Li metal, metals or alloys that react electrochemically with Li, carbon materials (e.g., graphite), silicon alloys, silicon oxides, and metal oxides (e.g., lithium titanate). The thickness of the negative electrode active material layer is preferably, for example, 1 to 300 μm.

[0053] (positive electrode) The positive electrode has a strip-shaped positive electrode current collector and a positive electrode active material layer formed on both sides of the positive electrode current collector. For the positive electrode current collector, a metal film, a metal foil (stainless steel foil, aluminum foil, or aluminum alloy foil), or the like is used.

[0054] The positive electrode active material layer contains a positive electrode active material and a binder, and optionally contains a conductive agent. The positive electrode active material is not particularly limited, but may be a lithium-containing composite oxide such as LiCoO2 or LiNiO2. The thickness of the positive electrode active material layer is preferably, for example, 1 to 300 μm.

[0055] The conductive agent contained in each active material layer is, for example, 0 to 20 parts by mass of the conductive agent per 100 parts by mass of the active material. The binder contained in the active material layer is, for example, fluororesin, acrylic resin, rubber particles, etc. The amount of the binder is, for example, 0.5 to 15 parts by mass of the binder per 100 parts by mass of the active material.

[0056] (Separator) As the separator, a resin microporous film or nonwoven fabric is preferably used. As the material (resin) of the separator, polyolefin, polyamide, polyamideimide, etc. are preferable. The thickness of the separator is, for example, 8 to 30 μm.

[0057] (electrolyte) The electrolyte may be a non-aqueous solvent in which a lithium salt is dissolved. Examples of the lithium salt include LiClO4, LiBF4, LiPF6, LiCF3SO3, LiCF3CO2, and imide salts. Examples of the non-aqueous solvent include cyclic carbonates such as propylene carbonate, ethylene carbonate, and butylene carbonate, chain carbonates such as diethyl carbonate, ethyl methyl carbonate, and dimethyl carbonate, and cyclic carboxylates such as γ-butyrolactone and γ-valerolactone.

[0058] Although a lithium ion secondary battery has been described above as an example, the present disclosure can be used in batteries in which the battery can is sealed using a sealing body, regardless of whether the battery is a primary battery or a secondary battery. [Industrial Applicability]

[0059] Batteries according to the present disclosure can be used in a variety of can-type batteries, and are suitable for use as power sources for, for example, portable devices, hybrid automobiles, electric automobiles, electrically assisted bicycles, electric motorcycles, and the like. [Explanation of symbols]

[0060] 10:Battery 110: Case 111:Cylinder part 112: Bottom 113: Opening edge 114: Groove 120: Electrode body 122: Internal lead 130: Sealing body 131: Sealing board 131A: Fixed part 131B: Periphery 131C: Thin wall part 131D:Protrusion 133: Gasket 135: Terminal material 135A: Top plate 135B: Side wall part 135C: Flange part 140: Internal insulation plate 141: Lead hole 150: Insulating material 160:Terminal board 160A: Central area 160B: Periphery 160C: Thin wall part 170: Weld marks 302: Current collecting member

Claims

1. A sealing plate made of a first metal; a terminal member made of a second metal different from the first metal and held by the sealing plate; the sealing plate has a fixing portion to which the terminal member is fixed, a ring-shaped peripheral portion located on a periphery, and a thin-walled portion formed between the fixing portion and the peripheral portion, the fixing portion has a protrusion protruding from an outer surface of the sealing plate, the protrusion is bent inwardly so that a portion of the terminal member is sandwiched between the fixed portion and the protrusion.

2. the terminal member has a top plate portion, a side wall portion bending and extending from a peripheral edge of the top plate portion toward the sealing plate, and a flange portion extending from an end of the side wall portion on the sealing plate side in a direction away from the top plate portion, The closure according to claim 1 , wherein the flange portion engages with the protrusion.

3. The sealing body according to claim 2 , wherein a joint is formed between the projection and the flange by welding.

4. The sealing body according to claim 3 , wherein the flange portion has a thickness smaller than a thickness of the side wall portion.

5. the first metal comprises aluminum; The sealing body according to any one of claims 1 to 3, wherein the second metal includes at least one of iron and nickel.

6. a case having a cylindrical portion, a bottom portion closing one end of the cylindrical portion, and an opening edge portion continuing to the other end of the cylindrical portion; An electrode body accommodated in the cylindrical portion; The sealing body according to any one of claims 1 to 5, The battery, wherein the sealing body is fixed to the opening edge portion so as to seal the opening of the opening edge portion.

7. an annular groove is formed on an outer peripheral surface of the cylindrical portion such that an inner peripheral surface of the cylindrical portion protrudes inwardly of the cylindrical portion; The sealing body further includes a gasket that covers the peripheral portion, The battery according to claim 6 , wherein the opening edge is bent so as to sandwich the gasket and the sealing plate between the opening edge and the groove, thereby sealing the gap between the sealing body and the opening edge.

Images