Sealing plate and power storage device using same

Abstract

A sealing plate of the present disclosure is provided with an annular flange portion provided at an outer periphery, an annular bulging portion positioned closer to the center than the flange portion and thicker than the flange portion, a flimsy portion positioned closer to the center than the bulging portion and being thinnest of the sealing plate, an annular transition portion positioned closer to the center than the flimsy portion, and a central portion positioned closer to the center than the transition portion and including the center of the sealing plate. In a thickness direction of the sealing plate, the flimsy portion is spaced apart from the flange portion in a first direction. In the thickness direction, the transition portion protrudes in a second direction opposite the first direction.

Description

[Technical Field]

[0001] The present disclosure relates to a sealing plate and an electricity storage device using the same. [Background technology]

[0002] Electricity storage devices are widely used as power sources for operating electronic devices and driving mobile objects such as automobiles. One example of such an electricity storage device is a cylindrical battery. This cylindrical battery has a sealing body including a valve body. This valve body seals the opening of the outer can with a gasket interposed between the opening and the outer can. Patent Document 1 listed below is a prior art document that discloses such a sealing body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6662377 Summary of the Invention [Problem to be solved by the invention]

[0004] The valve body is made by processing a metal material such as aluminum, and therefore has a certain level of reliability against external and internal stress. Meanwhile, in order to further increase the volume inside the power storage device and further reduce the size of the power storage device, sealing plates such as the valve body are required to be thinner. However, as the sealing plate becomes thinner, its resistance to the above-mentioned stress tends to decrease, and the reliability of the sealing plate tends to decrease. Therefore, an object of the present disclosure is to provide a highly reliable sealing plate and a power storage device using the same. [Means for solving the problem]

[0005] In one embodiment of the present disclosure, the sealing plate comprises an annular flange portion provided on the outer peripheral edge, an annular raised portion located closer to the center than the flange portion and thicker than the flange portion, a fragile portion located closer to the center than the raised portion and being the thinnest in the sealing plate, an annular relay portion located closer to the center than the fragile portion, and a central portion located closer to the center than the relay portion and including the center of the sealing plate, and when viewed radially of the sealing plate, in the thickness direction of the sealing plate, the fragile portion is separated from the flange portion in a first direction parallel to the thickness direction, and the relay portion protrudes in a second direction opposite to the first direction. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to improve the reliability of sealing plates used in power storage devices. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective cross-sectional view illustrating a portion of an example of a power storage device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a front cross-sectional view showing a part of the electricity storage device of FIG. 1. [Figure 3] FIG. 2 is a perspective cross-sectional view showing a portion of an example of a sealing plate according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a front cross-sectional view of the sealing plate of FIG. 3. [Figure 5A] FIG. 10 is a front cross-sectional view showing a modified example of the sealing plate according to the embodiment of the present disclosure. [Figure 5B] FIG. 10 is a front cross-sectional view showing another modified example of the sealing plate according to the embodiment of the present disclosure. [Figure 6A] FIG. 10 is a perspective cross-sectional view showing a part of a modified example of the power storage device according to the embodiment of the present disclosure. [Figure 6B] FIG. 10 is a perspective cross-sectional view showing a part of another modified example of the power storage device according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present disclosure will be described below with reference to preferred embodiments and drawings. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are intended to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0009] The sealing plate of the present disclosure includes an annular flange portion provided on the outer periphery, an annular raised portion located closer to the center than the flange portion and thicker than the flange portion, a weak portion located closer to the center than the raised portion and thinnest in the sealing plate, an annular relay portion located closer to the center than the weak portion, and a central portion located closer to the center than the relay portion and including the center of the sealing plate. In the thickness direction of the sealing plate, the weak portion is spaced apart from the flange portion in a first direction parallel to the thickness direction. Furthermore, the relay portion protrudes in a second direction opposite the first direction. With this configuration, the relay portion located closer to the center of the sealing plate than the weak portion is thicker, thereby reducing the protruding dimension when the weak portion protrudes in the second direction opposite the first direction away from the flange portion. Therefore, even if the relay portion and the central portion are thick, the thickness of the sealing plate as a whole can be suppressed. When the central portion, located closer to the center of the sealing plate than the relay portion, is configured to be thicker than the relay portion and protrudes in the same direction as the relay portion, the amount of protrusion can be suppressed in the same way as the relay portion. In addition, "in the thickness direction of the sealing plate, the weak portion is separated from the flange portion in a first direction parallel to this thickness direction." is, in other words, the minute portion and the weak portion do not overlap when viewed from the radial direction of the sealing plate (or the storage battery device).

[0010] Furthermore, in the sealing plate of the present disclosure, the first direction is above the sealing plate, the second direction is below the sealing plate, the lower surface of the relay portion may have a protruding slope, the raised portion may protrude upward from the upper surface of the flange portion, the fragile portion may be located above the flange portion, the slope of the relay portion may be formed on the lower surface of the relay portion, and the relay portion may be thicker on the central portion side than on the fragile portion side. This configuration allows the sealing plate to be thicker while suppressing a reduction in the volume inside the exterior housing of the energy storage device compared to a sealing plate in which the raised portion protrudes downward and the fragile portion is located below the sealing plate. Note that the sealing plate of the present disclosure does not necessarily have to have the raised portion protruding upward from the flange portion, the fragile portion located above the flange portion, and the slope not formed on the lower surface of the relay portion. For example, the raised portion may protrude downward from the flange portion, the fragile portion may be located below the flange portion, and the slope may be formed on the upper surface of the relay portion. Note that the lower surface of the relay portion is not limited to being sloped. The raised portion may protrude both above and below the flange portion. In this case, the weakened portion may be located either above or below the flange portion in the thickness direction of the flange portion when viewed from the radial direction. The lower surface of the relay portion may be stepped.

[0011] In addition, in the sealing plate of the present disclosure, the slope of the linking portion may overlap the flange portion when viewed from the radial direction. By extending the slope in this manner, the linking portion can be easily made thicker.

[0012] In the sealing plate of the present disclosure, the upper surface of the relay portion may be flat, and the upper surfaces of the fragile portion, the upper surfaces of the raised portion, and the upper surface of the relay portion may be flush with each other. With this configuration, the rigidity of the sealing plate of the present disclosure is increased when the sealing plate is pressed from the bottom toward the top by pressure within the energy storage device, compared to a sealing plate in which the relay portion has an annular slope formed so that the top surface of the sealing plate is recessed.

[0013] Furthermore, the sealing plate of the present disclosure may be thickest in the central portion of the sealing plate. With this configuration, when the lower surface of the central portion is joined to a lead that collects current from the electrodes of the electrode group, and when the upper surface of this central portion is joined to a current collecting member, higher reliability can be achieved when joining the current collecting member to the central portion.

[0014] Furthermore, an energy storage device using the sealing plate of the present disclosure may include an electrode group including a first electrode and a second electrode, an exterior body that houses the electrode group, and a sealing plate that closes the opening of the exterior body via an insulating gasket. The sealing plate may be the above-described sealing plate, and the first electrode may be electrically connected to the sealing plate, and the second electrode may be electrically connected to the exterior body. This configuration improves the reliability of the sealing plate, resulting in a more reliable energy storage device.

[0015] In an energy storage device using the sealing plate of the present disclosure, the exterior body may have a cylindrical portion that houses an electrode group therein, a bottom portion that closes one end of the cylindrical portion, and an opening portion provided at the other end of the cylindrical portion. The cylindrical portion may have a groove portion that is annularly recessed in the outer surface so that the inner peripheral surface of the cylindrical portion protrudes in the radial direction of the sealing plate. The gasket may be cylindrical and cover the upper and lower surfaces of the flange portion of the sealing plate, as well as the outer peripheral surface connecting the upper and lower surfaces of the flange portion. The sealing plate may be disposed on the inner peripheral surface of the groove via a cylindrical gasket, and the opening portion of the exterior body may have a crimping portion that tilts toward the center of the sealing plate and abuts against the upper surface of the flange portion via the gasket. This configuration improves the reliability of the sealing plate, thereby obtaining an energy storage device with higher reliability.

[0016] In addition, in an energy storage device using the sealing plate of the present disclosure, the raised portion of the sealing plate may protrude upward from the upper surface of the flange portion, and the gasket covering the upper surface of the flange portion may include an annular wall portion that extends from the crimped portion to near the raised portion and abuts the outer surface of the raised portion. This configuration can prevent a liquid pool from forming between the wall portion and the raised portion, compared to a configuration in which the wall portion is located near the tip of the crimped portion and away from the raised portion. Therefore, it is possible to prevent a short circuit between the case and the sealing plate due to the liquid in the pool. This effect is particularly effective when the upper end of the wall portion is located higher than the upper end of the crimped portion.

[0017] In addition, in an energy storage device using the sealing plate of the present disclosure, the upper end of the wall portion of the gasket may be located higher than the upper end of the sealing plate. This configuration allows the wall portion to separate the crimped portion electrically connected to the second electrode from the sealing plate electrically connected to the first electrode. This makes it easier to insulate the crimped portion from the sealing plate. (Embodiment) A sealing plate and an energy storage device using the same according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the following embodiments will be described based on the configuration of a nonaqueous secondary battery such as a lithium-ion secondary battery as an example of an energy storage device. However, the energy storage device according to the present disclosure is not limited to such a battery. The energy storage device according to the present disclosure may also be an alkaline storage battery, a capacitor, or the like.

[0018] Fig. 1 is a perspective cross-sectional view showing a portion of a power storage device 10 according to an embodiment of the present disclosure. Fig. 2 is a front cross-sectional view showing a portion of the power storage device 10. Note that in Fig. 1, hatching applied to the cut surface of the power storage device 10 has been omitted in consideration of ease of viewing. Furthermore, in Fig. 2, most of the outlines of the space behind the cut surface of the power storage device 10 have been omitted in consideration of ease of viewing.

[0019] As shown in Figures 1 and 2, the energy storage device 10 has an electrode group 11 including a first electrode and a second electrode, an outer casing 12 that houses the electrode group 11, a sealing plate 13 that seals an opening 12b of the outer casing 12 via a gasket 14, a lead 15 that electrically connects the sealing plate 13 and the first electrode, and an insulating plate 16 provided between the electrode group 11 and the sealing plate 13.

[0020] 3 is a perspective cross-sectional view showing a part of sealing plate 13. FIG. 4 is a front cross-sectional view of sealing plate 13 of FIG.

[0021] The sealing plate 13 is electrically connected to the first electrode of the electrode group 11 (the detailed configuration will be described later). Therefore, the sealing plate 13 is made of a conductive material. Examples of materials that form the sealing plate 13 include aluminum, copper, nickel, iron, titanium, and alloys of these metals. The sealing plate 13 is formed, for example, by processing the above-mentioned metal plate. As an example, aluminum is used for the sealing plate 13. The sealing plate 13 is, for example, a circular plate.

[0022] As shown in FIGS. 3 and 4 , the sealing plate 13 has an annular flange portion 13a provided on the outer periphery, an annular raised portion 13b located closer to the center of the sealing plate 13 than the flange portion 13a and thicker than the flange portion 13a, an annular weak portion 13c located closer to the center than the raised portion 13b and thinnest within the sealing plate 13, a relay portion 13d located closer to the center than the weak portion 13c, and a central portion 13e located closer to the center than the relay portion 13d and including the center. The weak portion 13c is spaced apart from the flange portion 13a in a first direction in the thickness direction of the sealing plate 13 (or the height direction of the energy storage device 10), and the relay portion 13d protrudes in a second direction opposite the first direction. Here, the first direction is defined as the upper side of the sealing plate 13, and the second direction is defined as the lower side of the sealing plate 13 (the direction facing the electrode group 11). However, the first direction may be downward and the second direction may be upward.

[0023] Flange portion 13a is a flat ring-shaped plate having an upper surface, a lower surface, and an outer circumferential surface connecting the upper surface and the lower surface. Flange portion 13a is fixed to exterior body 12 by being sandwiched in the thickness direction by groove portion 12d and crimping portion 12c of exterior body 12, which will be described later, via gasket 14. By making flange portion 13a thinner, the distance between groove portion 12d and crimping portion 12c can be reduced, and the space required for placing sealing plate 13 of electricity storage device 10 can be reduced.

[0024] The raised portion 13b is a portion of the sealing plate 13 that is thicker than the flange portion 13a. The raised portion 13b increases the rigidity of the sealing plate 13. The raised portion 13b extends from the flange portion 13a, and the raised portion 13b protrudes upward from the flange portion 13a. With this configuration, the crimped portion 12c and part of the gasket 14 can be accommodated in the space partitioned by the flange portion 13a and the raised portion 13b. This allows the dead space in the energy storage device 10 to be utilized.

[0025] The fragile portion 13c is annular and is the thinnest portion of the sealing plate 13. When the pressure inside the energy storage device 10 increases and exceeds a predetermined pressure, the fragile portion 13c is preferentially broken in the sealing plate 13. After breaking, the gas accumulated inside the energy storage device 10 is released from the broken portion. The breaking of the fragile portion 13c prevents the pressure inside the energy storage device 10 from increasing too much and causing the energy storage device 10 to burst at a location other than the fragile portion 13c. The fragile portion 13c is adjacent to the raised portion 13b in the radial direction.

[0026] The fragile portion 13c is formed on the upper end side of the raised portion 13b, and is therefore spaced upward from the flange portion 13a.

[0027] The relay portion 13d is a portion that connects the fragile portion 13c and the central portion 13e, which will be described later. The thickness of the relay portion 13d varies in the radial direction. Specifically, the relay portion 13d is thinner on the side of the fragile portion 13c and thicker on the side of the central portion 13e. This configuration makes it easier to form the fragile portion 13c compared to, for example, a relay portion that becomes thinner as it approaches the central portion. Furthermore, since it is possible to avoid forming a separate thin region at a location away from the fragile portion 13c, the reliability of the operation of the fragile portion 13c is improved, and since the relay portion 13d can be made thicker, the rigidity of the relay portion 13d can be increased.

[0028] To achieve the thickness relationship described above, an annular inclined surface 13f is formed on the lower surface of the relay portion 13d so as to protrude downward. One radial end of this inclined surface 13f is connected to the lower surface of the fragile portion 13c. The other end of the inclined surface 13f is connected to the upper end of the columnar portion below the central portion 13e. The upper surface of the relay portion 13d is a flat surface parallel to the radial direction. This configuration allows the relay portion 13d to be formed thick. The inclined surface 13f overlaps with the flange portion 13a when viewed from the radial direction. Furthermore, a portion of the annular inclined surface 13f extends downward from the flange portion 13a.

[0029] Central portion 13e is, for example, located at the center of sealing plate 13 and is the thickest portion of sealing plate 13. One end of lead 15 is joined to the underside of central portion 13e. The upper surface of central portion 13e has a flat surface parallel to the radial direction, and a current collecting member that electrically connects multiple electricity storage devices may be joined to it. Note that central portion 13e is the thickest portion of sealing plate 13 on the assumption that it will be joined to lead 15 by welding or to a current collecting plate by welding at central portion 13e; however, if the above joining is not taken into consideration, central portion 13e does not have to be the thickest portion of sealing plate 13. For example, central portion 13e may be thinner than protruding portion 13b.

[0030] Furthermore, the top surfaces of central portion 13e, relay portion 13d, fragile portion 13c, and raised portion 13b are flush with one another. With this configuration, even if a bending moment is applied to sealing plate 13 from flange portion 13a or the like, the top surfaces pull against one another, thereby suppressing deformation due to the moment, compared to sealing plates in which the above regions are not flush (specifically, the sealing plate has a recess in its top surface).

[0031] By increasing the rigidity of sealing plate 13 in this way, even if flange portion 13a is thin, it is possible to increase the rigidity of sealing plate 13 to a predetermined level. In addition, since the above-mentioned areas are flush with each other in the state where raised portion 13b is raised upward, it becomes easy to align it with the upper end of crimping portion 12c.

[0032] 5A is a front cross-sectional view of sealing plate 23, which is a modification of sealing plate 13. FIG. 5B is a front cross-sectional view of another modification of sealing plate 13.

[0033] 5A, in sealing plate 23, the inclination of inclined surface 23f does not change compared to sealing plate 13, and it directly connects to central portion 13e at a constant inclination. This configuration makes it easier to further thicken relay portion 23d of sealing plate 23, especially the central portion 23e side. This further increases the rigidity of relay portion 23d.

[0034] 5B , the underside of central portion 33e of sealing plate 33 is larger than that of sealing plate 23. With this configuration, when sealing plate 23 and sealing plate 33 have the same outer diameter and the same thicknesses of central portions 23e, 33e, slope 33f of relay portion 33d of sealing plate 33 has a steeper slope than slope 33f of relay portion 23d of sealing plate 23. The steeper slope makes relay portion 33d thicker than relay portion 23d, and the rigidity of relay portion 33d can be increased. The configuration of the electricity storage device 10 will be described again with reference to FIGS.

[0035] The electrode group 11 includes, for example, a strip-shaped first electrode, a strip-shaped second electrode, and a strip-shaped separator interposed between the first and second electrodes. The first electrode and the second electrode are wound with the separator interposed therebetween to form the electrode group 11.

[0036] The first electrode is, for example, a positive electrode. The positive electrode has, for example, a sheet-shaped current collector foil and a composite layer formed on at least one surface of the current collector foil. The current collector foil is made of a conductive material, such as aluminum, copper, nickel, iron, titanium, or an alloy of these metals. As an example, aluminum is used for the current collector foil of the first electrode of the electrode group 11. The composite layer contains a positive electrode active material, conductive particles, a binder, etc. Examples of the positive electrode active material include lithium composite metal oxides.

[0037] The second electrode is, for example, a negative electrode. The negative electrode has, for example, a sheet-shaped current collector foil and a composite layer formed on at least one surface of the current collector foil. The current collector foil is made of a conductive material, such as aluminum, copper, nickel, iron, titanium, or an alloy of these metals. As an example, copper is used for the current collector foil of the second electrode of the electrode group 11. The composite layer contains a negative electrode active material, conductive particles, a binder, etc. Examples of the negative electrode active material include a carbon material and a silicon compound.

[0038] The separator is made of an insulating material, such as a microporous film made of polypropylene. In the power storage device of the present disclosure, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0039] The exterior body 12 is electrically connected to the second electrode. Therefore, the exterior body 12 is made of a conductive material. Examples of materials for the exterior body 12 include aluminum, copper, nickel, iron, titanium, and alloys of these metals. For example, iron is used as the material for the exterior body 12.

[0040] The exterior body 12 has, for example, a cylindrical tube portion 12a, a bottom portion that closes one end of the tube portion 12a in the height direction of the energy storage device 10, and an opening portion 12b provided at the other end of the tube portion 12a in the height direction.

[0041] The bottom side of the cylindrical portion 12a accommodates the electrode group 11 together with the electrolyte. The winding axis of the electrode group 11 is parallel to the height direction of the energy storage device 10. An insulating plate 16 may be provided between the electrode group 11 and the bottom. In this case, the lead electrically connecting the second electrode to the outer casing 12 may bypass the insulating plate and connect to the bottom. Alternatively, a through hole may be formed in the insulating plate, and the lead may extend through the through hole. An annular groove 12d may be formed above the space in the cylindrical portion 12a accommodating the electrode group 11. This groove 12d is a depression extending circumferentially on the outer circumferential surface of the cylindrical portion 12a, and causes a corresponding portion of the inner circumferential surface of the cylindrical portion 12a to protrude radially. A gasket 14 is placed on the inner circumferential surface of this groove 12d. An insulating plate 16 may be interposed between the groove 12d and the electrode group 11. The insulating plate 16 may be made of insulating resin, rubber, or the like. Furthermore, the insulating plate 16 may have through holes formed therein through which the leads 15 are inserted.

[0042] The opening 12b is a region located above the groove 12d in the cylindrical portion 12a. A sealing plate 13 is fixed to the opening 12b via a gasket .

[0043] A crimped portion 12c is provided at the tip of opening 12b. Crimped portion 12c is formed by bending the tip of the opening so that it slopes down toward the center of sealing plate 13. By being bent so that crimped portion 12c slopes down, it presses the upper and lower surfaces of flange portion 13a of sealing plate 13, which is covered by gasket 14, in the thickness direction of sealing plate 13. Crimped portion 12c seals opening 12b together with sealing plate 13 and gasket 14. Furthermore, crimped portion 12c is electrically connected to the second electrode, and therefore may function as a connection point for a current collecting member.

[0044] The gasket 14 is, for example, an insulating elastic body. The gasket 14 is cylindrical and may have a bottom with a through-hole at the lower end in the thickness direction of the sealing plate 13. This bottom is interposed between the lower surface of the flange portion 13a and the inner circumferential surface of the groove portion 12d and is compressed by the crimping portion 12c. Furthermore, the protruding portion 13b, the fragile portion 13c, the relay portion 13d, and the central portion 13e of the sealing plate 13 are exposed to the inside of the exterior body 12 from the through-hole at the bottom of the gasket 14.

[0045] The upper end of the cylindrical portion of gasket 14 is bent so as to fall together with crimped portion 12c. By being bent, the upper end of the gasket is interposed between the upper surface of flange portion 13a and crimped portion 12c.

[0046] The gasket 14 may have a wall 14a at the tip of the upper end of the cylindrical portion, extending in the thickness direction of the sealing plate 13 when folded down together with the crimped portion 12c. This wall facilitates electrical insulation between the crimped portion 12c and the sealing plate 13. The wall 14a may be close to and abut against the side surface of the raised portion 13b that protrudes above the flange portion 13a from the crimped portion 12c. This configuration allows the crimped portion 12c to extend radially inward of the battery. This allows for a wider area for connection with the current collecting member when the crimped portion 12c is used as the connection point. Furthermore, the upper end of the wall 14a abutting against the side surface of the raised portion 13b may be higher in the thickness direction than the upper end of the sealing plate 13. With this configuration, the crimped portion 12c, the sealing plate 13, and the wall portion 14a are separated from each other, and the sealing plate 13 and the crimped portion 12c can be more easily insulated from each other.

[0047] The lead 15 electrically connects the first electrode of the electrode group 11 to the sealing plate. The lead 15 is made of a conductive material. Examples of materials for the lead 15 include aluminum, copper, nickel, iron, titanium, and alloys of these metals. The lead 15 is ribbon-shaped, and one end thereof is connected to a portion of the first electrode where no composite layer is formed. The other end thereof is joined to the underside of the central portion 13e of the sealing plate 13.

[0048] Fig. 6A is a perspective cross-sectional view showing a modified example of the energy storage device 10. Fig. 6B is a perspective cross-sectional view showing another modified example of the energy storage device 10. In Figs. 6A and 6B, hatching applied to the cross-section of the energy storage device 10 has been omitted for ease of viewing.

[0049] 6A , a modified example of the energy storage device 10 has a gasket 44 instead of the gasket 14. The gasket 44 has a wall portion 44a that is in contact with the side surface of the raised portion 13b, which is similar to the wall portion 14a. However, a portion of the wall portion 44a may be separated from the sealing plate 13.

[0050] 6B, another modification of power storage device 10 has a gasket 54 instead of gasket 14. Wall portion 54a at the tip of gasket 54 is arranged to cover the tip of crimped portion 12c. This allows for more reliable insulation between sealing plate 13 and crimped portion 12c. [Industrial Applicability]

[0051] The sealing plate and the power storage device using the same according to the present disclosure have improved reliability as a sealing plate. This allows for charging and discharging of a higher-performance power storage device and charging and discharging under more severe environments. Therefore, the sealing plate and the power storage device using the same according to the present disclosure can be used in a wide range of fields, such as a power source for electronic devices and a driving power source for a driving body. [Explanation of symbols]

[0052] 10. Energy storage device 11 electrode group 12 Exterior body 12a Cylinder part 12b opening 12c Crimping part 12d Groove 13, 23, 33 Sealing plate 13a Flange 13b Ridge 13c Weak area 13d, 23d, 33d relay section 13e, 23e, 33e center 13f, 23f, 33f slopes 14, 44, 54 Gaskets 14a, 44a, 54a wall 15 Lead 16 Insulating plate

Claims

1. A sealing plate used in an electricity storage device, The sealing plate is an annular flange portion provided on the outer circumferential edge; an annular protrusion portion located closer to the center than the flange portion and thicker than the flange portion; a weak portion located closer to the center than the protruding portion and having the thinnest thickness in the sealing plate; an annular relay portion located closer to the center than the fragile portion; a central portion located closer to the center than the relay portion and including the center of the sealing plate, In a thickness direction of the sealing plate, the fragile portion is spaced apart from the flange portion in a first direction parallel to the thickness direction, the relay portion protrudes in a second direction opposite to the first direction in the thickness direction, the first direction is above the sealing plate and the second direction is below the sealing plate, The lower surface of the relay portion has a protruding slope, The raised portion protrudes upward from the upper surface of the flange portion, the weakened portion is located above the flange portion, the slope of the relay portion is formed on the lower surface of the relay portion, The relay portion is thicker on the central portion side than on the weak portion side, The upper surface of the relay portion is a flat surface, an upper surface of the fragile portion, an upper surface of the protruding portion, and an upper surface of the relay portion are flush with each other; Sealing board.

2. When viewed from the radial direction, the inclined surface of the relay portion overlaps with the flange portion. The sealing plate according to claim 1 .

3. The sealing plate has a thickness that is greatest in the central portion. The sealing plate according to claim 1 or 2.

4. an electrode group including a first electrode and a second electrode; an exterior body that houses the electrode group; a sealing plate that closes the opening of the exterior body via an insulating gasket, The sealing plate is the sealing plate according to any one of claims 1 to 3, the first electrode is electrically connected to the sealing plate; The second electrode is electrically connected to the outer casing. Energy storage device.

5. the exterior body has a cylindrical portion that houses the electrode group therein, a bottom portion that closes one end of the cylindrical portion, and the opening portion that is provided at the other end of the cylindrical portion, the cylindrical portion has an annular groove recessed in an outer peripheral surface such that an inner peripheral surface of the cylindrical portion protrudes in a radial direction, the gasket is cylindrical and covers an upper surface, a lower surface, and an outer circumferential surface connecting the upper surface and the lower surface of the flange portion of the sealing plate; the sealing plate is provided on the inner circumferential surface of the groove portion via a cylindrical gasket, The opening of the exterior body has a crimping portion that tilts toward the center and abuts against the upper surface of the flange portion via the gasket. The power storage device according to claim 4.

6. The raised portion of the sealing plate protrudes upward from the upper surface of the flange portion, The gasket covering the upper surface of the flange portion extends from the crimped portion to near the raised portion and includes an annular wall portion abutting against an outer surface of the raised portion. The power storage device according to claim 5 .

7. The upper end of the wall portion is located above the upper end of the sealing plate. The electricity storage device according to claim 6.

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