Power storage device

Abstract

The disclosed power storage device includes: a housing; a power storage element arranged in the housing; a lead connected to an electrode of the power storage element; and a sealing member that seals an opening of the housing. The sealing member includes: a gasket including a disc-shaped base; and a conductive sealing plate. The base is arranged between the sealing plate and the power storage element. A through hole is formed in the base. A protrusion of the sealing plate is inserted into the through hole. The protrusion of the sealing plate is connected to the lead. As the internal pressure in the housing increases, the protrusion is displaced in a direction away from the lead, thereby cutting off the connection between the protrusion and the lead.

Description

Technical Field

[0001] The present disclosure relates to a power storage device. Background Art

[0002] At present, power storage devices such as secondary batteries and capacitors are used in various fields. For example, these power storage devices are also used in power tools, power-assisted bicycles, and electric vehicles, and their capacity is being increased.

[0003] The power storage devices used in various fields need to show high safety even in harsh use environments. Therefore, in the past, explosion-proof valves, current cut-off mechanisms (CIDs), etc. were set in secondary batteries and the like to ensure safety. For example, as a secondary battery, a cylindrical battery is known, which has: an electrode body, a cylindrical outer can, and a sealing body riveted to the opening of the outer can via a gasket, the sealing body comprising: a valve body having a circular shape and riveted to the gasket, a metal plate arranged closer to the inside of the battery than the valve body and connected to the central part of the valve body, and an annular insulating member between the outer periphery of the valve body and the outer periphery of the metal plate (for example, patent document 1). In this cylindrical battery, when the pressure in the outer can rises, the central part of the valve body moves to the outside of the battery due to the pressure. The valve body is separated from the metal plate by the force of this movement. In addition, the connection between the valve body and the metal plate is cut off, which can cut off the current path in the cylindrical battery. In this cylindrical battery, a sealing mechanism and a safety mechanism of the outer can are installed using at least a valve body, a metal plate, an insulating member, and a gasket.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 157749 Summary of the invention

[0007] -Problems to be solved by the invention-

[0008] The above-mentioned power storage device requires a large number of components to achieve the functions of sealing and safety. This may deteriorate the workability when assembling the power storage device. Therefore, a sealing member that can ensure safety with a simpler structure is required. Under such circumstances, one of the purposes of the present disclosure is to provide a power storage device that is low-cost, can be manufactured efficiently, and has high safety.

[0009] -Methods for solving the problem-

[0010] One aspect of the present disclosure relates to an electric storage device. The electric storage device comprises: a housing having a cylindrical barrel, a bottom that blocks one end of the barrel, and an opening provided at the other end of the barrel; an electric storage element that is arranged in the housing and includes a pair of electrodes; a lead that is connected to one of the pair of electrodes; and a sealing member that seals the opening of the housing, the sealing member comprising: a gasket having an insulating property and including a disc-shaped base, and a sealing plate having conductivity, the sealing plate having: a displacement portion having a protrusion protruding toward the electric storage element, and an outer peripheral portion provided around the displacement portion, the base being arranged between the sealing plate and the electric storage element, a through hole being formed in the base, the protrusion of the sealing plate being inserted into the through hole, the protrusion of the sealing plate being connected to the lead, and the protrusion is displaced in a direction away from the lead as the internal pressure in the housing rises, thereby cutting off the connection between the protrusion and the lead.

[0011] -Effects of the Invention-

[0012] According to the present disclosure, the number of parts that have the functions of sealing and safety is reduced, so that a power storage device that can be manufactured efficiently at low cost and has high safety can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view schematically showing an example of the power storage device of the present disclosure.

[0014] Figure 2 It is schematically indicated Figure 1 A perspective view of a sealing member and a lead wire used in the power storage device shown.

[0015] Figure 3 yes Figure 1 A perspective view schematically showing a sealing member and a lead wire used in the power storage device shown in FIG.

[0016] Figure 4 It is schematically indicated Figure 1 A top view of the power storage device shown.

[0017] Figure 5 It is for Figure 1 A bottom view schematically showing another example of a sealing member and a lead wire used in the power storage device shown.

[0018] Figure 6 It is for Figure 1 A bottom view schematically showing another example of a sealing member and a lead wire used in the power storage device shown.

[0019] Figure 7 It is schematically indicated Figure 1 A cross-sectional view showing a manufacturing process of the power storage device shown. DETAILED DESCRIPTION

[0020] Hereinafter, the embodiments of the present disclosure will be described with examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may also be applied as long as the effects of the present disclosure can be obtained.

[0021] (Electricity storage device)

[0022] The power storage device disclosed in the present invention includes: a shell having a cylindrical barrel, a bottom that blocks one end of the barrel, and an opening provided at the other end of the barrel; a power storage element that is arranged in the shell and includes a pair of electrodes; a lead that is connected to one of the pair of electrodes; and a sealing member that seals the opening of the shell. The sealing member includes: a gasket that has insulation and includes a disc-shaped base, and a sealing plate that has conductivity. The sealing plate includes: a displacement portion formed with a protrusion protruding toward the power storage element, and an outer peripheral portion provided around the displacement portion. The base of the gasket is arranged between the sealing plate and the power storage element. A through hole is formed in the base. The protrusion of the sealing plate is inserted into the through hole. The protrusion of the sealing plate is connected to the lead. As the internal pressure in the shell rises, the protrusion is displaced in a direction away from the lead, so that the connection between the protrusion and the lead is cut off. Hereinafter, the through hole formed in the disk-shaped base of the gasket may be referred to as a “through hole (G)”, and the protrusion of the sealing plate inserted into the through hole (G) may be referred to as a “protrusion (P)”.

[0023] In the power storage device disclosed in the present invention, the displacement portion (protrusion (P)) of the sealing plate is displaced in a direction away from the lead as the internal pressure in the shell increases. Furthermore, by displacing the protrusion (P) of the sealing plate in a direction away from the lead, the connection between the protrusion (P) of the sealing plate and the lead can be cut off. That is, the sealing plate and the lead can function as a current interrupt device (Current Interrupt Device: CID). The CID cuts off the current collection path in the power storage device when gas is retained in the shell due to overcharging, etc., causing the pressure in the shell to exceed a specified value. By cutting off the current collection path, the charging and discharging of the power storage device with rising pressure can be prevented. Furthermore, it is possible to prevent the power storage device from becoming unsafe, rupturing due to increased pressure, etc.

[0024] Furthermore, in the power storage device disclosed in the present invention, in addition to the function of the above-mentioned CID, when the internal pressure in the shell further increases, the sealing plate can break and release the gas in the shell to the outside of the shell. By means of such a sealing plate, the rupture of the power storage device disclosed in the present invention can be suppressed. Therefore, safety is further improved. Compared with the existing sealing components that perform the above-mentioned functions, the sealing member disclosed in the present invention has fewer parts and a simpler structure. Therefore, through the present disclosure, a power storage device that maintains safety and reduces manufacturing costs and assembly man-hours can be obtained.

[0025] Furthermore, since the sealing member of the present disclosure has a small number of parts, the volume of the parts can be reduced compared to conventional sealing members having the same function. Therefore, the power storage device of the present disclosure can improve the energy density compared to conventional power storage devices.

[0026] The power storage device may be a secondary battery or a capacitor. The power storage device may also be a non-aqueous electrolyte secondary battery (lithium ion secondary battery, lithium battery, etc.), a nickel-hydrogen secondary battery, etc. The power storage device may also be an electric double layer capacitor using activated carbon as an electrode material, or a lithium ion capacitor, etc.

[0027] There is no particular limitation on the storage element, and it can be selected according to the type of storage device. A known storage element can be used for the storage element. For example, in the case where the storage device is a secondary battery, a storage element including a positive electrode, a negative electrode, a separator, and an electrolyte can also be used. The negative electrode of an example lithium-ion secondary battery contains a substance that reversibly absorbs / releases lithium ions as a negative electrode active material. The negative electrode active material includes, for example, carbon materials such as graphite, inorganic compounds such as silicon and titanium oxide. The positive electrode of these secondary batteries may also include a transition metal composite oxide containing lithium as a positive electrode active material. The transition metal composite oxide includes, for example, elements such as nickel, manganese, cobalt, and aluminum.

[0028] When the power storage device is a capacitor, a power storage element including two electrodes, an electrolyte, and a separator may be used. These components can be selected according to the type of capacitor.

[0029] (case)

[0030] The housing can function as one of the electrode terminals, for example. In the case where the housing functions as an electrode terminal, for example, the housing can also be formed using a conductive metal, and one electrode of the storage element (the electrode not electrically connected to the sealing plate) is electrically connected to the housing. For example, the negative electrode is electrically connected to the housing. In the storage device of the present disclosure, the positive electrode can also be connected to the housing.

[0031] The shell has: a cylindrical barrel, a bottom that blocks the opening at one end of the barrel, and an opening at the other end of the barrel. The barrel may also have an annular groove protruding from the outer circumference of the shell to the inner circumference of the shell in the radial direction of the barrel. A sealing member can be arranged on the groove. The opening end of the shell is bent toward the inner side of the barrel (the central axis side of the barrel) in the radial direction of the barrel by riveting. The further bent opening end is riveted to the outer periphery of the sealing plate via the folded portion of the gasket of the sealing member described later. The sealing member can be clamped by the riveted opening end and the groove. Thus, the opening of the shell is sealed. For example, a metal shell can be used for the shell. The metal shell may include aluminum, iron, nickel-copper, or alloys or composite materials of these metals. The shell of the storage device is not limited to the above-mentioned structure, and a known shell may also be used.

[0032] (lead)

[0033] The lead electrically connects the electrode of the storage element to the sealing plate. For the lead, a lead used in a known storage device can be used. A strip of metal foil can also be used for the lead. Examples of metals (conductive metals) constituting the lead include aluminum, iron, nickel, copper, or alloys or composite materials containing multiple metals among these metals. One end of the lead can be connected to any one of the two electrodes of the storage element, but in the case where the storage device is a secondary battery, for example, the lead is connected to the positive electrode.

[0034] The other end of the lead or its vicinity is connected (fixed) to the sealing plate. That is, the lead is electrically and physically connected to the sealing plate. The method of connecting the lead to the sealing plate is not particularly limited, for example, welding can be used. Among them, in order to function as a CID, when the force separating the lead from the sealing plate becomes larger, a connection method in which the connection between the lead and the sealing plate can be releasable (i.e., fixed and released) is required. In the case where the lead is joined to the sealing plate by welding. By changing the conditions such as the welding area and welding depth, the force required to peel the lead from the sealing plate can be adjusted. The welding method is not particularly limited, and laser welding, resistance welding, friction stirring, ultrasonic bonding, etc. can also be used.

[0035] From the viewpoint of reducing the number of components, the lead is preferably directly connected to the sealing plate, but the lead and the sealing plate may be indirectly connected via a conductive member as long as the CID can function.

[0036] (Sealing plate)

[0037] The sealing plate is, for example, a circular plate having conductivity. The sealing plate functions as an electrode terminal, or may also function as a displacement member that electrically connects an electrode terminal (e.g., a terminal cap) to a lead. The sealing plate is formed, for example, of a metal plate, such as a metal including aluminum, nickel, copper, iron, or an alloy or composite material including multiple metals among these metals. For the sealing plate, a known sealing plate (valve body, etc.) can be used.

[0038] The sealing plate may also include: a displacement portion that is displaced according to the internal pressure in the housing, and an outer peripheral portion formed around the displacement portion. A collector portion having a protrusion protruding toward the lead is formed in the displacement portion. The front end of the protrusion may be located at the opening (or near the opening) of the through hole (G) on the storage element side, or at a position closer to the storage element than the opening of the through hole (G).

[0039] The displacement portion of the sealing plate may also be displaced according to a pressure above a prescribed level in the shell. At this time, a thin-walled portion thinner than the peripheral portion may also be formed in the displacement portion. For example, the sealing plate may include a thin-walled portion thinner than the collector portion and the peripheral portion between the portion (collector portion) forming the protrusion (P) and the peripheral portion. The displacement portion may include, for example, a circular plate or a dome shape. In the case where the sealing plate includes a dome-shaped displacement portion, the dome-shaped displacement portion is configured to be a convex portion toward the side of the storage element. In order to increase the displacement of the protrusion (P), the protrusion (P) may, for example, be formed in the center of the displacement portion of the sealing plate (the center of the collector portion).

[0040] The shape of the front end face of the protrusion (the face to which the lead is connected) may also be a shape having a long side direction along the direction extending from the region facing the sealing member in the region of the lead. With this structure, even if the area of ​​the region in the lead that is bonded to the sealing plate is not expanded in all directions, it is easy to expand the bonding area. Therefore, it is easy to improve the bonding strength between the lead and the protrusion. In addition, the distance from the edge of the region in the lead that is bonded to the bonding portion is easy to shorten. Therefore, when the sealing plate is displaced, the above-mentioned bonded region is difficult to bend. Therefore, it is difficult for the lead to follow when the sealing plate is displaced. The width of the front end face having the above-mentioned long side direction may, for example, be narrower than the width of the portion of the lead connected to the front end face. That is, for example, the entire front end face of the protrusion may also be covered by the lead. In addition, in the displacement portion, the thickness of the portion (collecting portion) forming the protrusion may also be thicker than the region outside it. With this structure, a protrusion having a size substantially the same as the protruding height of the protrusion is formed as a depression compared to the back side of the protrusion in the displacement portion (the upper surface of the sealing plate), which can suppress the delay in the operation timing of the CID.

[0041] When the CID function is activated and the sealing plate and the lead are broken, the internal pressure in the housing further increases, and the displacement of the sealing plate becomes particularly large, the thin-walled portion of the sealing plate breaks, and the gas inside the housing is released to the outside of the housing. This can prevent the housing from breaking.

[0042] (liner)

[0043] The gasket includes a material having elasticity and insulation for functioning as a gasket. That is, the gasket has insulation. The gasket may also include a known material used in the gasket of a secondary battery or a capacitor. Examples of gasket materials include: polypropylene (PP), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA) and polyetheretherketone (PEEK). Additives (such as known additives) may also be added to these materials as needed. The formation method of the gasket is not limited, and it may also be formed by methods such as injection molding.

[0044] The gasket includes, for example, a rising portion extending from the peripheral edge of the base in a direction away from the storage element, and an annular folded portion extending from the end of the rising portion toward the inner side of the housing (the central axis of the housing) and covering at least a portion of the upper surface of the outer peripheral portion of the sealing plate. The rising portion and the folded portion are arranged between the inner peripheral surface of the housing near the opening end and the sealing plate to insulate the housing from the sealing plate.

[0045] The cross-sectional shape of the through hole (G) formed at the base of the gasket (the shape of the cross section perpendicular to the thickness direction of the base of the gasket) is not particularly limited to the shape into which the protrusion of the sealing plate can be inserted. The shape of the through hole may also be, for example, circular, elliptical, rectangular (including square) or rounded rectangular. In addition, the shape of the opening of the through hole may also match the shape of the protrusion having the above-mentioned long side direction, and may be a shape having a long side direction parallel to the long side direction of the front end face. In order to suppress the lead from following when the displacement portion of the sealing plate is displaced, the through hole (G) of the gasket may also reduce the gap between the opening on the lead side and the protrusion (P). Therefore, when observing the protrusion and the gasket of the sealing plate from the side of the storage element, the shape of the protrusion and the shape of the opening of the through hole of the gasket may also be almost the same size / shape. The position of the through hole corresponds to the position of the protrusion of the sealing plate. The through hole may also be formed, for example, in the central portion of the disc-shaped base or in the vicinity thereof.

[0046] The power storage device of the present disclosure may also satisfy the following structures (1) and (2).

[0047] (1) The gasket includes: a rising portion extending from the peripheral edge of the base in a direction away from the energy storage element, and an annular folded portion extending from the end of the rising portion (the end farther from the energy storage element) toward the inner side of the shell (the central axis of the shell) and covering at least a portion of the upper surface of the outer peripheral portion of the sealing plate.

[0048] (2) An annular groove is formed on the outer circumferential surface of the cylindrical portion of the housing, and the region where the groove is formed on the inner circumferential surface of the cylindrical portion protrudes toward the inner side of the housing. The sealing member is located on the groove, and the other end of the cylindrical portion is bent toward the inner side of the housing and abuts against the upper surface of the folded portion. Here, the upper surface refers to the surface that is farther from the storage element.

[0049] The sealing plate may have a thin-walled portion between the current collecting portion and the outer peripheral portion where the protrusion is formed and which is thinner than the current collecting portion and the outer peripheral portion.

[0050] The inner circumferential surface (side surface) of the through hole (G) may also be inclined so that the through hole (G) becomes thinner as it approaches the lead. That is, the inner circumferential surface of the through hole of the gasket may also have a tapered shape that becomes thinner from the sealing plate side to the storage element side. By using a through hole of the above shape, the displacement of the protrusion (P) of the sealing plate becomes smooth, and the reliability of the CID in the storage device is improved.

[0051] When the through hole of the gasket has the above-mentioned tapered shape, the outer peripheral surface of the protrusion (P) of the sealing plate may also have a tapered shape that becomes thinner as it approaches the storage element. With this structure, the displacement of the protrusion (P) of the sealing plate becomes smooth, and the reliability of the CID in the storage device is improved.

[0052] The outer peripheral surface of the protrusion (P) of the sealing plate may also be in contact with the inner peripheral surface of the through hole (G). Through this structure, the protrusion (P) can be held by the gasket, so that the sealing plate and the lead can be prevented from breaking when the CID is not working. Alternatively, a gap may be formed between the outer peripheral surface of the protrusion and the inner peripheral surface of the through hole (G). That is, the protrusion may also have a shape in which at least a portion is not in contact with the inner peripheral surface of the through hole (G). Through this structure, when the protrusion is welded to the lead, the heat can be prevented from being conducted from the protrusion to the gasket. As a result, problems caused by deformation of the gasket due to heat (such as non-conformity related to displacement of the sealing plate, etc.) can be suppressed.

[0053] A vent hole for transmitting the internal pressure in the shell to the sealing plate may also be formed at the base of the gasket. The internal pressure in the shell can also be transmitted to the sealing plate only through the through hole (G) through which the protrusion (P) of the sealing plate is inserted. However, by forming a vent hole, the internal pressure in the shell can be transmitted to the sealing plate more quickly and reliably. In this case, the vent hole may also be set at a position that does not overlap with the lead. Through this structure, it is possible to prevent the lead from clogging the vent hole when gas flows into the vent hole. However, in the power storage device disclosed in the present invention, if there is no concern that the lead will clog the vent hole, the vent hole may also be set at a position overlapping with the lead.

[0054] The through hole (G) may have a longitudinal direction along one direction (first direction), and the protrusion (P) of the sealing plate may have a longitudinal direction along the first direction when viewed from the bottom of the housing. Hereinafter, the first direction may be referred to as "first direction D1".

[0055] The lead may include a strip portion connected to the protrusion (P) of the sealing plate, the strip portion and the protrusion (P) may be connected by a welding portion, and the welding portion may have a longitudinal direction along the first direction D1 when viewed from the bottom of the case.

[0056] The lead may include a strip-shaped portion connected to the protrusion (P) of the sealing plate, and an edge of one end of the lead in the extending direction may intersect with the first direction D1 when viewed from the bottom of the case.

[0057] At least one rib (for example, a plurality of ribs) may also be provided on the surface of the lead side in the base of the gasket. By providing the rib, the rigidity of the base of the gasket can be improved, and when the CID is working, it is difficult for the lead to follow the displacement of the sealing plate. Furthermore, by providing the rib, a part of the lead can be clamped on the rib, and when the CID is working, it is difficult for the lead to follow the displacement of the sealing plate. Therefore, the reliability of the function of the CID can be improved. In addition, the rib also makes it easy to position the lead when the lead is connected to the sealing plate. Therefore, the lead is prevented from being displaced, and pressure is applied to the joint position between the lead and the sealing plate. In addition, when the gasket forms a vent hole, it is possible to prevent the vent hole from overlapping the lead.

[0058] The movement of the lead can also be suppressed by the interference between the lead and at least one of the above-mentioned ribs. That is, the movement of the lead can also be suppressed by the lead being clamped to the above-mentioned rib. In the case where the lead is displaced with the displacement of the protrusion (P) of the sealing plate, even if the displacement of the protrusion (P) becomes larger, the connection between the sealing plate and the lead may be difficult to release. By utilizing the interference between the ribs formed on the pad and the lead to suppress the displacement of the lead, the reliability of the CID can be improved. In the case where the displacement of the lead is suppressed by the interference between the lead and the rib, the distance between the lead and the rib at the position of the interference can also be set to a range of 0 to 0.6 mm.

[0059] At least one rib formed at the base of the gasket may also include two ribs configured to sandwich a through hole (G) of the base. Furthermore, the lead may also include a strip portion that is arranged between the two ribs and connected to the protrusion (P) of the sealing plate. As examples of the configuration of the leads and ribs in this case, the first and second examples are described below. In addition, the two ribs may also be arranged approximately parallel to each other. In this specification, the term "approximately parallel" means arranged in parallel or at an angle close thereto, for example, the angle formed by the directions in which the two ribs extend is less than 10°.

[0060] In the first example, the lead and the two ribs may also be of the following structure. The lead includes a wide portion connected to a strip portion (for example, one end of the strip portion in the long side direction) and wider than the strip portion. Furthermore, the width of the wide portion is wider than the distance between the two ribs. With this structure, the area on the periphery of the wide portion that faces the ribs engages with the ribs. Therefore, it is difficult for the lead to be displaced when the sealing plate is displaced. In addition, in this structure, the ribs may not be two. Even if there is only one rib, the displacement of the lead can be suppressed compared to a structure with no ribs at all. In addition, at this time, the edges of the wide portion and the strip portion may be a shape connecting multiple straight lines, or may include curves.

[0061] In the second example, the lead and the two ribs may also be the following structure. The lead includes two wide width portions that are respectively connected to the two ends of the strip (for example, one end in the long side direction of the strip and the other end on the opposite side thereof) and are wider than the strip. The widths of the two wide width portions are respectively wider than the distance between the two ribs. In addition, the lead is configured so that the two wide width portions clamp at least a portion of the two ribs. Through this structure, the area facing the ribs in the periphery of the wide width portion is clamped to the ribs. Through this clamping, the lead is difficult to move when the sealing plate is displaced. Connected (fixed) to the sealing plate. In other words, it can also be said that a cutout portion is formed at both ends of the strip in the width direction, and the above-mentioned two ribs are accommodated in the pair of cutout portions. In addition, the above-mentioned cutout portions and ribs may not be two. The cutout portion and the rib may also be only one each, and the lead is difficult to move compared to a structure without ribs and cutout portions. In addition, the rib can also be a columnar shape filling most of the cutout portion, or a shape extending along the shape of the edge of the cutout portion. In addition, the shape of the edge of the cutout portion can be rectangular, or can be U-shaped, V-shaped, or C-shaped.

[0062] In addition, a through hole can also be formed in the strip-shaped portion of the lead, and the rib can be embedded in the through hole. In this case, the through hole formed in the lead can also be a circular hole or a rectangular hole. In addition, when the pad and the lead are observed from the electrode group side, the shape of the hole can be almost the same as the shape of the rib, or the rib can be smaller than the opening of the hole. In the case where the through hole of the strip-shaped portion is embedded in the rib, the lead can also be pressed into the rib. Thereby, the lead can be fixed to the pad more firmly. In addition, when the sealing plate and the lead are observed from the electrode group side, the through hole of the lead can also be arranged in the long side direction of the strip-shaped portion with the front end surface of the protrusion.

[0063] The power storage device disclosed in the present invention may also include a terminal cap (not shown) connected to a sealing plate. The terminal cap may also include a conductive material (e.g., a conductive metal) including a convex portion that functions as a terminal. The terminal cap may also include a flat annular portion and a convex portion formed in the center of the portion. The terminal cap is arranged on the side opposite to the power storage element relative to the sealing plate. That is, the sealing plate is arranged between the terminal cap and the power storage element. In one example, the peripheral portion of the terminal cap overlaps the peripheral portion of the sealing plate, and the two peripheral portions are riveted at the open end of the shell via a gasket. In this case, a vent hole for releasing the gas inside the shell when the sealing plate is broken may also be formed in the terminal cap.

[0064] In addition, one aspect of the present disclosure relates to the above-mentioned sealing member. As described above, the sealing member involved in the present disclosure includes: a gasket including a disc-shaped base and a conductive sealing plate, the base is arranged between the sealing plate and the storage element, a through hole (G) is formed in the base, and a protrusion (P) provided on the displacement portion of the sealing plate is inserted into the through hole (G).

[0065] Hereinafter, an example of an electric storage device of the present disclosure and an example of an example of a manufacturing method thereof will be specifically described with reference to the accompanying drawings, but the electric storage device of the present disclosure is not limited to the following contents. The above-mentioned structural elements can be applied to the structural elements of the electric storage device of the example described below. In addition, the structural elements of the electric storage device of the example described below can be changed based on the above description, and structural elements that are not necessary in the electric storage device of the present disclosure can also be omitted. In addition, the matters described below can also be applied to the above-mentioned embodiments.

[0066] (Implementation Method 1)

[0067] In the first embodiment, an example of the power storage device of the present disclosure will be described. Figure 1Schematically shows a cross-sectional view of an electric storage device 100 according to Embodiment 1. The electric storage device 100 includes: a housing 10, an electric storage element 20 disposed in the housing 10, leads 21 and 22 connected to electrodes (not shown) of the electric storage element 20, and a sealing member 40 for sealing an opening of the housing 10. The electric storage device 100 further includes insulating plates 23 and 24. The insulating plates 23 and 24 are respectively disc-shaped members having through holes formed therein.

[0068] The sealing member 40 includes a gasket 41 including a disc-shaped base 41a and a sealing plate 42. The base 41a is disposed between the sealing plate 42 and the storage element 20. A through hole 41h is formed in the center of the base 41a. The base 41a has a planar shape having a size that is almost the same as the planar shape (circular) of the sealing plate 42. The peripheral edge of the base 41a is in close contact with the peripheral edge of the sealing plate 42.

[0069] The housing 10 has: a cylindrical barrel 10b, a bottom 10c that blocks one end of the barrel 10b, and an opening 10d that constitutes the other end (opening end) of the barrel 10b. An annular groove 10a is formed near the opening 10d of the barrel 10b in the radial direction of the barrel 10b and protrudes from the outside of the housing 10 to the inside of the housing 10. The sealing member 40 is arranged on the inner peripheral surface of the groove 10a. The opening end at the opening 10d of the housing 10 is riveted to the outer peripheral portion of the sealing plate 42 via a gasket 41. As a result, the sealing member 40 is clamped by the groove 10a and the opening end, and the housing 10 is sealed.

[0070] The gasket 41 includes a rising portion 41b extending from the peripheral edge of the base 41a in a direction away from the energy storage element 20, and an annular folded portion 41d extending from the end of the rising portion 41b toward the inside of the case 10 and covering at least a portion of the upper surface of the outer peripheral portion 42p of the sealing plate 42.

[0071] The sealing plate 42 includes a dome-shaped displacement portion 42d that is a convex portion toward the storage element 20 side, and an outer peripheral portion 42p provided around the displacement portion 42d. At least a portion of the displacement portion 42d is thinned so that it breaks if the displacement of the displacement portion 42d increases. A collector portion having a protrusion 42a protruding toward the storage element 20 side is provided in the central portion (collector portion) 42c of the displacement portion 42d. The protrusion 42a of the sealing plate 42 is inserted into the through hole 41h of the gasket 41. The front end surface of the protrusion 42a may be on the same plane as or near the surface 41s on the storage element 20 side of the gasket 41, or may protrude toward the storage element 20 side more than the surface 41s. The lead 21 is fixed (connected) to the front end surface of the protrusion 42a.

[0072] The sealing plate 42 has a thin portion 42t that is thinner than the outer peripheral portion 42p. More specifically, the sealing plate 42 has a thin portion 42t between the central portion 42c forming the protrusion 42a and the outer peripheral portion 42p.

[0073] In addition, in Embodiment 1, an example is shown in which there is no gap between the protrusion 42a and the through hole 41h, but there may be a gap between them. That is, the protrusion 42a and the side surface (inner peripheral surface) of the through hole 41h may not be in contact. In addition, in Embodiment 1, an example is shown as follows, namely: the shape of the opening of the through hole 41h is an oblong shape having a long side direction along the first direction D1, and the shape of the front end surface of the protrusion 42a is a shape having a long side direction parallel to the long side direction of the opening of the through hole 41h, but these may also be other shapes mentioned above. For example, the protrusion 42a and the through hole 41h may also be truncated cone shapes, respectively.

[0074] The connection portion C (eg, welding portion) between the protrusion 42a and the lead 21 is as follows: Figure 5 as well as Figure 6 As shown, the longitudinal direction may be along the first direction D1.

[0075] Figure 2 Schematically shows a perspective view of the lead wire 21 and the sealing member 40 viewed from the surface 41s side. Figure 2 middle, Figure 3 Schematically shows a partially exploded perspective view in which a portion of the pad 41 and the lead 21 are removed. Figure 4 Schematically shows a top view of the power storage device 100 when viewed from the sealing plate 42 side. Figure 1 The cross-sectional view is along Figure 3 A cross-sectional view of the ridge-shaped protrusion 42a in the longitudinal direction is shown.

[0076] like Figure 2 as well as Figure 3 As shown, a plurality of vent holes (through holes) 41c are formed in the base portion 41a of the gasket 41. The vent holes 41c communicate with the displacement portion 42d so that the internal pressure in the housing 10 is transmitted to the displacement portion 42d.

[0077] Two ribs 41r are formed on the surface 41s of the base 41a of the gasket 41. The two ribs 41r are arranged substantially in parallel with the through hole 41h. Each rib 41r extends in a direction parallel to the longitudinal direction (first direction D1) of the protrusion 42a.

[0078] The rib 41r is, for example, a linear convex portion. The lead 21 includes a strip portion 21a disposed between two ribs 41r. The shape of the front end surface of the protrusion 42a is smaller than the planar shape of the strip portion 21a. A portion of the strip portion 21a is fixed to the front end surface of the protrusion 42a by welding or the like.

[0079] When the internal pressure in the housing 10 increases, the protrusion 42a of the displacement portion 42d moves in a direction away from the storage element 20 (i.e., away from the lead 21). On the other hand, the movement of the lead 21 is suppressed by the base 41a. Therefore, when the displacement of the protrusion 42a increases, the connection between the protrusion 42a and the lead 21 breaks and the connection is released. As a result, overcharging and the like can be suppressed.

[0080] When the internal pressure in the housing 10 further increases and the displacement of the displaceable portion 42 d further increases, the thin-walled portion 42 t or its peripheral edge portion breaks. As a result, the gas in the housing 10 is released to the outside of the housing 10 .

[0081] exist Figure 2 as well as Figure 3 In the structure shown, the movement of the strip portion 21a is suppressed by the rib 41r. Specifically, the movement of the strip portion 21a in a direction perpendicular to the long side direction of the strip portion 21a (the direction parallel to the first direction D1) can be suppressed. Furthermore, the movement of the strip portion 21a in the long side direction of the strip portion 21a can also be suppressed by the interference between the lead 21 and the rib 41r. Figure 5 The first example of this method is schematically shown in FIG. Figure 6 The second example is schematically shown in FIG. Figure 5 as well as Figure 6 These are diagrams showing a portion of the lead 21 and the pad 41 as viewed from the surface 41 s side.

[0082] exist Figure 5 In one example, the lead 21 includes: a strip portion 21a disposed between two ribs 41r, and a wide portion 21b connected to one end of the strip portion 21a and having a width greater than the width Wa of the strip portion 21a. Such a lead 21 can be formed by cutting a metal plate into a predetermined shape (for example, Figure 6 The same is true for the lead wire 21 shown in FIG. 1 ). The width Wb of the wide portion 21b is wider than the distance L between the two ribs 41r. Therefore, the movement of the strip portion 21a is suppressed by the interference between the wide portion 21b and the two ribs 41r. Figure 5 In the case of the example shown, the strip-shaped portion 21 a is prevented from moving in the direction of the arrow A. At this time, the rib portion 41 r is bent and extended in a crank shape (step shape) along the shape of the peripheral edge of the lead 21 .

[0083] exist Figure 6In one example, the lead 21 includes: a strip portion 21a disposed between two ribs 41r, and two wide portions 21b connected to both ends of the strip portion 21a in the long side direction and having a width wider than the width Wa of the strip portion 21a. The two wide portions 21b are configured to sandwich at least a portion of the two ribs 41r. The width Wb of the two wide portions 21b is wider than the distance L between the two ribs 41r. Therefore, the movement of the strip portion 21a is suppressed by the interference between the two wide portions 21b and the two ribs 41r. Figure 6 In the case of the example shown, the strip-shaped portion 21a can be suppressed from moving in the directions of arrows A and B. In addition, the widths Wb of the two wide portions 21b may be the same or different.

[0084] Furthermore, in the above-described example, when viewed from the bottom portion 10 c of the housing 10 , the edge portion at one end of the direction in which the lead wire 21 extends intersects with the first direction D1 .

[0085] The following, Figure 1 An example of a method for manufacturing the power storage device 100 shown in FIG. Figure 7 The groove portion 10a is formed after the energy storage element 20 is arranged in the shell 10. The lead 21 is connected to one of the electrodes of the energy storage element 20 and the protrusion 42a. The lead 22 is connected to the shell 10. Next, the open end of the shell 10 is bent inward, and the outer peripheral portion 42p of the sealing plate 42 is riveted while clamping the cylindrical wall portion of the gasket 41. Through this process, the folded portion 41d is formed from the cylindrical wall portion. In this way, the energy storage device 100 can be manufactured. The processes used in the known method for manufacturing energy storage devices can be applied to these processes.

[0086] Industrial Applicability

[0087] The present disclosure can be utilized in a power storage device.

[0088] -Explanation of symbols-

[0089] 10 Housing

[0090] 20 Storage element

[0091] 21, 22 Lead

[0092] 40 Sealing components

[0093] 41 Pad

[0094] 41a Base

[0095] 41b Rising part

[0096] 41c Ventilation hole

[0097] 41d Turning section

[0098] 41h Through hole

[0099] 41r Rib

[0100] 42 Sealing plate

[0101] 42a Protrusion

[0102] 42d Displacement

[0103] 100 Power storage device

[0104] Connecting portion C (welding portion).

Claims

1. A power storage device, comprising: a housing having a cylindrical barrel, a bottom portion blocking one end of the barrel, and an opening provided at the other end of the barrel; a power storage element disposed in the housing and comprising a pair of electrodes; a lead wire connected to one of the pair of electrodes; and a sealing member that seals the opening of the housing, The sealing member includes: a gasket having insulating properties and including a disc-shaped base; and sealing plate, which is conductive, The sealing plate includes: a displacement portion formed with a protrusion protruding toward the electric storage element; and an outer peripheral portion provided around the displacement portion. The base is arranged between the sealing plate and the energy storage element. A through hole is formed in the base, The protrusion of the sealing plate is inserted into the through hole, The protrusion of the sealing plate is connected to the lead, As the internal pressure in the housing increases, the protrusion is displaced in a direction away from the lead, thereby cutting off the connection between the protrusion and the lead. At least one rib is provided on the surface of the base portion on the lead side, The at least one rib includes two ribs arranged to sandwich the through hole, The lead includes a strip portion disposed between the two ribs and connected to the protrusion of the sealing plate. The lead includes a wide portion connected to the strip-shaped portion and having a width wider than the strip-shaped portion. The width of the wide portion is wider than the distance between the two ribs.

2. The power storage device according to claim 1, wherein The gasket includes: a rising portion extending from the peripheral edge of the base in a direction away from the storage element; and an annular folded portion extending from the end of the rising portion toward the inner side of the housing and covering at least a portion of the upper surface of the outer peripheral portion of the sealing plate. An annular groove is formed on the outer peripheral surface of the cylindrical portion of the housing. The region where the groove is formed on the inner peripheral surface of the cylinder protrudes toward the inner side of the housing. The sealing member is located on the groove portion, The other end of the cylindrical portion is bent toward the inner side of the housing and abuts against the upper surface of the folded portion.

3. The power storage device according to claim 1, wherein The sealing plate has a thin-walled portion between the current collecting portion on which the protrusion is formed and the outer peripheral portion, and the thin-walled portion is thinner than the current collecting portion and the outer peripheral portion.

4. The power storage device according to claim 1, wherein The inner peripheral surface of the through hole is inclined so that the through hole becomes thinner as it approaches the lead.

5. The power storage device according to claim 1, wherein The base portion is formed with a vent hole for transmitting the internal pressure in the housing to the sealing plate.

6. The power storage device according to claim 1, wherein The through hole has a longitudinal direction along a first direction, and the protrusion of the sealing plate has a longitudinal direction along the first direction when viewed from the bottom of the housing.

7. The power storage device according to claim 6, wherein: The lead includes a strip portion connected to the protrusion of the sealing plate, The strip portion and the protrusion are connected by a welding portion, The weld portion has a longitudinal direction along the first direction when viewed from the bottom portion of the housing.

8. The power storage device according to claim 6, wherein: The lead includes a strip portion connected to the protrusion of the sealing plate, When viewed from the bottom of the housing, an edge portion at one end of a direction in which the lead wire extends intersects with the first direction.

9. A power storage device, comprising: a housing having a cylindrical barrel, a bottom portion blocking one end of the barrel, and an opening provided at the other end of the barrel; a power storage element disposed in the housing and comprising a pair of electrodes; a lead wire connected to one of the pair of electrodes; and a sealing member that seals the opening of the housing, The sealing member includes: a gasket having insulating properties and including a disc-shaped base; and sealing plate, which is conductive, The sealing plate includes: a displacement portion formed with a protrusion protruding toward the electric storage element; and an outer peripheral portion provided around the displacement portion. The base is arranged between the sealing plate and the energy storage element. A through hole is formed in the base, The protrusion of the sealing plate is inserted into the through hole, The protrusion of the sealing plate is connected to the lead, As the internal pressure in the housing increases, the protrusion is displaced in a direction away from the lead, thereby cutting off the connection between the protrusion and the lead. At least one rib is provided on the surface of the base portion on the lead side, The at least one rib includes two ribs arranged to sandwich the through hole, The lead includes a strip portion disposed between the two ribs and connected to the protrusion of the sealing plate. The lead includes two wide portions connected to both ends of the strip-shaped portion and wider than the strip-shaped portion. The widths of the two wide portions are respectively wider than the distance between the two ribs. The lead is arranged so that the two wide portions sandwich at least a portion of the two ribs.

10. The power storage device according to claim 9, wherein: The gasket includes: a rising portion extending from the peripheral edge of the base in a direction away from the storage element; and an annular folded portion extending from the end of the rising portion toward the inner side of the housing and covering at least a portion of the upper surface of the outer peripheral portion of the sealing plate. An annular groove is formed on the outer peripheral surface of the cylindrical portion of the housing. The region where the groove is formed on the inner peripheral surface of the cylinder protrudes toward the inner side of the housing. The sealing member is located on the groove portion, The other end of the cylindrical portion is bent toward the inner side of the housing and abuts against the upper surface of the folded portion.

11. The power storage device according to claim 9, wherein The sealing plate has a thin-walled portion between the current collecting portion on which the protrusion is formed and the outer peripheral portion, and the thin-walled portion is thinner than the current collecting portion and the outer peripheral portion.

12. The power storage device according to claim 9, wherein The inner peripheral surface of the through hole is inclined so that the through hole becomes thinner as it approaches the lead.

13. The power storage device according to claim 9, wherein The base portion is formed with a vent hole for transmitting the internal pressure in the housing to the sealing plate.

14. The power storage device according to claim 9, wherein The through hole has a longitudinal direction along a first direction, and the protrusion of the sealing plate has a longitudinal direction along the first direction when viewed from the bottom of the housing.

15. The power storage device according to claim 14, wherein: The lead includes a strip portion connected to the protrusion of the sealing plate, The strip portion and the protrusion are connected by a welding portion, The weld portion has a longitudinal direction along the first direction when viewed from the bottom portion of the housing.

16. The power storage device according to claim 14, wherein The lead includes a strip portion connected to the protrusion of the sealing plate, When viewed from the bottom of the housing, an edge portion at one end of a direction in which the lead wire extends intersects with the first direction.

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