JP6565491B2 - Power storage device - Google Patents

Description

  This specification discloses the technique regarding the electrical storage apparatus provided with the electric current interruption apparatus.

  In the technical field of power storage devices, development of a current interrupting device that cuts off the current flowing between the electrode terminals (positive electrode terminal and negative electrode terminal) when the power storage device is overcharged or when a short circuit occurs inside is underway. . The current interrupting device of Patent Document 1 is driven using a pressure difference between the inside and outside of the case. Specifically, when the pressure in the case exceeds a predetermined value, the current interrupt device is driven and the current path is interrupted. The electrode terminal of Patent Document 1 is a rivet type having a through hole, and is caulked and fixed to a case. In the power storage device of Patent Document 1, a rubber plug is inserted into a through hole of a rivet type electrode terminal.

JP 2010-212034 A

  In the power storage device of Patent Document 1, by inserting a rubber plug into the through hole of the electrode terminal, liquid (electrolyte solution, washing water, etc.) adheres to the current interrupting device through the through hole during manufacture. It is preventing. By preventing the liquid from adhering to the current interrupting device, the current interrupting device is prevented from deteriorating. By inserting a rubber plug into the through hole, it is possible to prevent a large amount of moisture from attaching to the current interrupting device through the through hole. However, the power storage device of Patent Document 1 cannot prevent moisture passing through the rubber plug from adhering to the current interrupt device. For this reason, in the power storage device of Patent Document 1, it is impossible to prevent deterioration of the current interrupting device due to adhesion of moisture over a long period of time. The present specification provides a technique for realizing a power storage device including a highly reliable current interrupting device.

  The power storage device disclosed in this specification includes a case, an electrode assembly, an electrode terminal, a current interrupt device, and a sealing plug. The electrode assembly is accommodated in the case and includes a positive electrode and a negative electrode. The electrode terminal passes through the inside and outside of the case and has a through hole. The current interruption device is accommodated in the case and is fixed to the electrode terminal. The current interrupt device switches the electrode terminal and the positive electrode or the negative electrode from the conductive state to the non-conductive state when the pressure in the case exceeds a predetermined value. The sealing plug seals the through hole of the electrode terminal. The sealing plug has a metal part and a resin part covering the periphery of the metal part.

  In the above power storage device, the sealing plug has a metal part and a resin part covering the periphery of the metal part. Metals have extremely low moisture permeability compared to resins. Therefore, by using a sealing plug having a metal portion and a resin portion, moisture passing through the inside of the sealing plug can be significantly reduced as compared with a conventional power storage device. Note that a metal sealing plug can also be used in view of the low moisture permeability. However, in the metal sealing plug, a gap is generated between the through hole and the sealing plug. In order to seal the gap, an operation such as welding the sealing plug to the through hole (electrode terminal) is required. The welding heat may adversely affect other parts of the power storage device. If it is said sealing stopper, the clearance gap between a sealing stopper and a through-hole can be sealed, without performing welding etc., suppressing a water | moisture content passing the inside of a sealing stopper. Water that passes through the through-hole from the outside of the power storage device and enters the power storage device is significantly reduced, and a power storage device including a highly reliable current interrupting device can be realized.

Sectional drawing of the electrical storage apparatus of 1st Example is shown. The enlarged view of the range enclosed with the broken line II of FIG. 1 is shown. The perspective view of a sealing stopper is shown. The characteristic part of the electrical storage apparatus of 2nd Example is shown.

  Hereinafter, some technical features of the power storage device disclosed in this specification will be described. The items described below have technical usefulness independently.

  The power storage device includes a case, an electrode assembly, an electrode terminal, a current interrupt device, and a sealing plug. The electrode assembly is accommodated in the case and may include a positive electrode and a negative electrode. The electrode terminal may pass through the inside and outside of the case. That is, a part of the electrode terminal may be located outside the case, and the other part of the electrode terminal may be located inside the case. The electrode terminal may have a through hole. One opening of the through hole may be located outside the case, and the other opening may be located inside the case. The electrode terminal may include a base portion that extends along the wall surface of the case inside the case, a shaft portion that passes through the inside and outside of the case, and a caulking portion that is caulked and deformed outside the case. The material of the negative electrode may be copper, copper alloy, or nickel.

  The electric current interruption apparatus may be accommodated in the case. Moreover, the electric current interruption apparatus may be fixed to the electrode terminal (a negative electrode terminal or a positive electrode terminal). The current interrupt device may be electrically connected to the negative electrode terminal and the negative electrode. In this case, the current interrupt device is disposed on the energization path between the negative electrode terminal and the negative electrode, and switches the negative electrode terminal and the negative electrode from the conductive state to the nonconductive state when the internal pressure of the case exceeds a predetermined value. Alternatively, the current interrupt device may be electrically connected to the positive terminal and the positive electrode. In this case, the current interrupt device is disposed on the energization path between the positive terminal and the positive electrode, and switches the positive terminal and the positive electrode from the conductive state to the non-conductive state when the internal pressure of the case exceeds a predetermined value.

  The current interruption device may include an energization plate and a deformation plate. The energization plate may be disposed at a position facing the base with a gap from the base of the electrode terminal. The energization plate may be disposed between the deformation plate and the electrode assembly. The deformation plate may be fixed to the electrode terminal. Specifically, the end of the deformation plate may be fixed to the electrode terminal. The through hole of the electrode terminal may be covered with the deformation plate. The central portion of the deformable plate may protrude toward the energizing plate and be fixed to the energizing plate. The deformation plate may be activated when the pressure in the case exceeds a predetermined value, and may be in non-contact with the energization plate. The deformable plate may be reversed so as to be separated from the energizing plate when the pressure in the case exceeds a predetermined value. When the pressure in the case exceeds a predetermined value, the central portion of the energizing plate may be broken and the deformed plate may be separated from the energizing plate. A groove (breaking groove) that becomes a starting point of breakage when the pressure in the case exceeds a predetermined value may be provided in the central portion of the energization plate. The fracture | rupture groove | channel may surround the center part of the electricity supply board continuously or intermittently. The central portion of the deformable plate may be fixed to the energizing plate at a position surrounded by the breaking groove.

  The current interrupt device may include two deformation plates (a first deformation plate and a second deformation plate). In this case, the energization plate may be provided between the first deformation plate and the second deformation plate. The second deformation plate may be provided between the energization plate and the electrode assembly. A protrusion that protrudes toward the energizing plate may be provided on the energizing plate side of the second deformable plate. In other words, the second deformation plate may be disposed on the opposite side of the first deformation plate with respect to the current supply plate, and may include a protrusion protruding toward the current supply plate on the current supply plate side. The protrusion may be opposed to the portion surrounded by the fracture groove in a state of being separated from the current-carrying plate.

  The sealing plug may be inserted into the through hole of the electrode terminal. Moreover, the sealing plug may have a metal part and a resin part covering the periphery of the metal part. The resin part may be welded to the electrode terminal. More specifically, the sealing plug may be welded to the wall surface of the through hole of the electrode terminal. The sealing plug may include an insertion portion that is inserted into the through hole and an expansion portion that is provided at an end portion of the insertion portion and has a size larger than that of the through hole. The extension part may be welded to the crimping part of the electrode terminal. The material of the resin portion may be butyl rubber, perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), or polypropylene (PP). The material of the metal part may be copper, a copper alloy, or nickel. In particular, copper or a composite material containing copper or a copper alloy is preferable. The material of the metal part may contain the same element as the element constituting the material of the electrode terminal. More preferably, the metal part and the electrode terminal are made of the same material.

  As examples of the power storage device disclosed in this specification, a secondary battery, a capacitor, and the like can be given. As an example of an electrode assembly of a secondary battery, a stacked electrode assembly in which a plurality of cells having electrode pairs (a negative electrode and a positive electrode) opposed via a separator are stacked, and a sheet having an electrode pair opposed via a separator And a wound electrode assembly in which the cells are spirally processed.

  An electrode assembly and an electrolytic solution are accommodated in the case. The electrode assembly includes a positive electrode and a negative electrode. As the metal foil for the positive electrode, aluminum (Al), nickel (Ni), titanium (Ti), stainless steel, or a composite material thereof can be used. In particular, aluminum or a composite material containing aluminum is preferable. Moreover, the material similar to the metal foil for positive electrodes can be used as a material of a positive electrode lead.

The positive electrode active material only needs to be a material in which lithium ions can enter and desorb, and Li ₂ MnO ₃ , Li (NiCoMn) _0.33 O ₂ , Li (NiMn) _0.5 O ₂ , LiMn ₂ O ₄ , LiMnO _2, LiNiO _2, and _{LiCoO 2, LiNi 0.8 Co 0.15 Al} 0.05 O 2, Li 2 MnO 2, LiMn 2 O 4 or the like can be used. In addition, alkali metals such as lithium and sodium, or sulfur can be used as the positive electrode active material. These may be used alone or in combination of two or more. A positive electrode active material is apply | coated to the metal foil for positive electrode with a electrically conductive material, a binder, etc. as needed.

  As the metal foil for the negative electrode, aluminum, nickel, copper (Cu) or the like, or a composite material thereof can be used. In particular, copper or a composite material containing copper is preferable. Moreover, the material similar to the metal foil for negative electrodes can be used as a material of a negative electrode lead.

  As the negative electrode active material, a material in which lithium ions can enter and leave is used. Alkali metals such as lithium (Li) and sodium (Na), transition metal oxides containing alkali metals, natural graphite, mesocarbon microbeads, highly oriented graphite, carbon materials such as hard carbon, soft carbon, silicon alone or silicon A containing alloy or a silicon-containing oxide can be used. The negative electrode active material is particularly preferably a material that does not contain lithium (Li) in order to improve battery capacity. A negative electrode active material is apply | coated to the metal foil for negative electrodes with a electrically conductive material, a binder, etc. as needed.

  As the separator, a porous porous material is used. As the separator, a porous film made of a polyolefin-based resin such as polyethylene (PE) or polypropylene (PP), or a woven or non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methyl cellulose or the like can be used.

The electrolytic solution is preferably a nonaqueous electrolytic solution in which a supporting salt (electrolyte) is dissolved in a nonaqueous solvent. As a non-aqueous solvent, a solvent containing a chain ester such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl acetate, A solvent such as methyl propionate or a mixture thereof can be used. Moreover, as a supporting salt (electrolyte), for _example, can be used LiPF _6, LiBF 4, LiAsF _6, and the like.

  The power storage device disclosed in this specification is mounted on, for example, a vehicle and can supply electric power to a motor. Hereinafter, the structure of the power storage device will be described. In the following description, a power storage device in which a current interrupt device is connected on a conduction path between a negative electrode terminal and a negative electrode will be described. The technology disclosed in this specification can also be applied to a power storage device in which a current interrupting device is connected on a conduction path between a positive electrode terminal and a positive electrode.

(First embodiment)
The structure of the power storage device 100 will be described with reference to FIG. The power storage device 100 includes a case 1, an electrode assembly 3, a positive electrode terminal 5, a negative electrode terminal 7, a current interrupt device 10, and a sealing plug 15. Case 1 is made of metal and has a substantially rectangular parallelepiped shape. Inside the case 1, an electrode assembly 3 and a current interrupt device 10 are accommodated. The electrode assembly 3 includes a positive electrode and a negative electrode (not shown). The positive electrode tab 41 is fixed to the positive electrode, and the negative electrode tab 42 is fixed to the negative electrode. An electrolyte is injected into the case 1 to remove the atmosphere. The positive terminal 5 and the negative terminal 7 are fixed to the lid 1 a of the case 1. The positive terminal 5 communicates with the inside and outside of the case 1 through the opening 81 of the lid portion 1a. The negative terminal 7 communicates with the inside and outside of the case 1 through the opening 82 of the lid 1a. The material of the positive electrode terminal 5 is aluminum, and the material of the negative electrode terminal 7 is copper.

  Resin insulators 62 and 63 are disposed on the upper surface of the lid 1a. The insulator 62 is fixed to the positive electrode terminal 5. A positive external terminal (metal plate) 60 is disposed on the upper surface of the insulator 62. A through hole 60 a is formed in the positive external terminal 60. The through hole 60a is larger in size on the lower surface side than on the upper surface side. The insulator 62 insulates the lid 1a from the positive external terminal 60. The bolt 64 passes through the through hole 60a. Specifically, the head of the bolt 64 is accommodated in the through hole 60a. The shaft portion of the bolt 64 protrudes above the positive electrode external terminal 60 through the through hole 60a. The positive electrode terminal 5, the positive electrode external terminal 60, and the bolt 64 are electrically connected, and they can be combined as a positive electrode terminal. The insulator 63 is fixed to the negative electrode terminal 7. A negative external terminal 61 is disposed on the upper surface of the insulator 63. The negative electrode external terminal 61 is also formed with a through hole similar to the through hole 60a of the positive electrode external terminal 60. The head of the bolt 65 is accommodated in the through hole, and the shaft portion of the bolt 65 passes through the through hole. Projecting above the negative external terminal 61. The configurations of the insulator 63, the negative external terminal 61, and the bolt 65 are the same as the configurations of the insulator 62, the positive external terminal 60, and the bolt 64. The negative electrode terminal 7, the negative electrode external terminal 61, and the bolt 65 are electrically connected, and these can be combined to be regarded as a negative electrode terminal.

  A current interrupt device 10 is fixed to the negative terminal 7. A negative electrode lead 44 connected to the negative electrode tab 42 is connected to the current interrupt device 10 via a connection terminal 46. That is, the current interrupt device 10 is electrically connected to the negative electrode of the electrode assembly 3. An insulating member 73 is disposed between the negative electrode lead 44 and the case 1. The insulating member 73 insulates the negative electrode lead 44 from the case 1 (lid portion 1a). A positive electrode lead 43 connected to the positive electrode tab 41 is connected to the positive electrode terminal 5. An insulating member 72 is disposed between the positive electrode lead 43 and the case 1. The insulating member 72 insulates the positive electrode lead 43 from the case 1 (lid portion 1a). The positive terminal 5 is electrically connected to the positive electrode of the electrode assembly 3.

  With reference to FIG. 2, the structure of the negative electrode terminal 7 and the electric current interruption apparatus 10 is demonstrated. As shown in FIG. 2, the negative terminal 7 is caulked and fixed to the case 1. The negative external terminal 61 and the gasket 63 are fixed to the case 1 together with the negative terminal 7. The negative electrode terminal 7 includes a base portion 95, a columnar portion 94, and a caulking portion 96. A columnar portion 94 connects the base portion 95 and the caulking portion 96. The columnar portion 94 passes through the opening 82 of the case 1. The columnar portion 94 extends from the central portion of the base portion 95. A through hole 97 is formed in the columnar portion 94. The upper surface of the base portion 95 has a flat surface that extends along the lid portion 1 a of the case 1. A protruding portion 99 that protrudes downward (on the electrode assembly 3 side) is provided at the end of the base portion 95. That is, when observed from inside the case 1, a recess 98 is formed at the center of the base 95, and a through hole 97 is formed at the center of the recess 98. The base portion 95 is provided inside the case 1, and the caulking portion 96 is provided outside the case 1.

  The current interrupt device 10 is fixed to the negative terminal 7. The current interrupt device 10 includes an energization plate 20, a deformation plate 30, and a holder 80. The deformation plate 30 is a metal diaphragm. The outer peripheral portion 31 of the deformation plate 30 is fixed to the protruding portion 99 of the base portion 95. Specifically, the outer peripheral portion 31 is welded to the protruding portion 99. A central portion 32 of the deformation plate 30 protrudes downward (on the electrode assembly 3 side). The central portion 32 is connected to the energizing plate 20. The space in the case 1 is sealed from the space 51 in the recess 98 by the deformation plate 30. The space 51 is maintained at atmospheric pressure.

  The energization plate 20 is a metal flat plate. The energizing plate 20 is disposed at a position facing the base portion 95 with a gap from the base portion 95 of the negative electrode terminal 7. The energization plate 20 is disposed below the deformation plate 30. That is, the energization plate 20 is disposed between the deformation plate 30 and the electrode assembly 3. A metal connection terminal 46 is connected to the energizing plate 20. The conductive plate 20 and the negative electrode lead 44 are electrically connected by the connection terminal 46 (see also FIG. 1). An end 20 e of the energization plate 20 is fixed to the holder 80. A groove 20 a is formed in the central portion 20 c of the energization plate 20. The groove 20a surrounds the center portion 20c. The central portion 32 of the deformable plate 30 is fixed to the central portion 20c of the energizing plate 20 within a range surrounded by the groove 20a. The mechanical strength of the current-carrying plate 20 at the position where the groove 20a is formed is lower than the mechanical strength of the current-carrying plate 20 at a position other than the groove 20a. A vent hole 20b is formed between the central portion 20c and the end portion 20e. The space 50 between the deformation plate 30 and the energization plate 20 communicates with the space in the case 1 by the vent hole 20b. That is, the space 50 is equal to the pressure in the case 1. Since the space 50 is sealed from the space 51 by the deformation plate 30, a pressure difference may be generated between the front and back surfaces of the deformation plate 30.

  The holder 80 has an upper end portion 79, a central portion 78, and a protruding portion 76. The upper end 79 has a flat surface that extends along the lid 1 a of the case 1. A through hole 79 a is formed at the center of the upper end 79. The columnar portion 94 of the negative electrode terminal 7 is provided in the through hole 79a. The upper end 79 is disposed between the lid 1 a of the case 1 and the base 95 of the negative electrode terminal 7. The holder 80 is fixed to the case 1 together with the negative electrode terminal 7. The holder 80 is formed of an insulating material, and insulates the case 1 and the negative electrode terminal 7.

  The central portion 78 extends downward from the outer peripheral edge of the upper end portion 79. The base portion 95 of the negative electrode terminal 7 is disposed inside the central portion 78. A protrusion 76 is provided at the lower end of the central portion 78. The energizing plate 20 is fixed to the protruding portion 76. A recess 77 is formed on the inner surface of the protrusion 76. A seal member 75 is disposed between the recess 77, the outer surface of the projecting portion 99 of the base portion 95, and the surface of the current-carrying plate 20. It is sealed.

  The sealing plug 15 has a metal part 16 and a resin part 14. The sealing plug 15 is inserted into the through hole 97. The sealing plug 15 includes an insertion portion 15 a that is inserted into the through hole 97 and an expansion portion 15 b that is located outside the through hole 97. The size of the extended portion 15 b is larger than the size of the through hole 97. The extended portion 15 b is located on the caulking portion 96 of the negative electrode terminal 7. In the insertion portion 15 a, the resin portion 14 is welded to the wall surface of the through hole 97. In addition, the resin portion 14 is welded to the caulking portion 96 in the extended portion 15b. Further, the metal portion 16 of the extended portion 15 b is welded to the caulking portion 96. The material of the metal part 16 is copper, and the material of the resin part 14 is PP.

  The sealing plug 15 will be described with reference to FIG. As described above, the sealing plug 15 has the metal portion 16 and the resin portion 14. In addition, the sealing plug 15 includes an insertion portion 15a and an expansion portion 15b. The resin part 14 covers the periphery of the metal part 16 including the insertion part 15a and the extension part 15b. In other words, the resin portion 14 is provided on the surface of the metal portion 16 and goes around the surface of the metal portion 16. Specifically, the resin portion 14 covers the periphery of the metal portion 16 in the insertion portion 15a (see the circumferential surface and the bottom surface, see FIG. 2) and the lower surface of the metal portion 16 in the extension portion 15b. Therefore, even if the sealing plug 15 is inserted into the through hole 97 of the negative electrode terminal 7, the surface of the metal portion 16 is exposed to the outside of the through hole 97.

  In addition, the resin part may coat | cover only the lower surface of the metal part 16 in the expansion part 15b, and does not need to coat | cover the insertion part 15a. Also in this case, it can be said that the resin portion makes a round on the surface of the metal portion 15 (see FIGS. 2 and 3). Or the resin part does not need to coat | cover only the surrounding surface of the insertion part 15a, and has coat | covered the lower surface of the metal part 16 in the expansion part 15b. Also in this case, it can be said that the resin portion makes a round on the surface of the metal portion 15. Further, the resin portion may not cover the bottom surface of the insertion portion 15a. That is, if the resin part has a structure that seals between the metal part 16 and the through hole 97, the range in which the resin part is provided can be selected as appropriate. The structure in which the resin portion 14 covers the periphery of the insertion portion 15a and the lower surface of the expansion portion 15b like the sealing plug 15 is simple in the manufacturing process of covering the metal portion 16 with the resin portion 14, and a long seal length is confirmed. Has the advantage of being able to.

  In the power storage device 100, the negative electrode terminal 7 and the negative electrode tab 42 are electrically connected via the current interrupt device 10 when the pressure in the case 1 is equal to or lower than a predetermined value. That is, the negative electrode terminal 7 and the negative electrode are electrically connected. When the pressure in the case 1 exceeds a predetermined value, the current interrupt device 10 interrupts conduction between the negative electrode terminal 7 and the negative electrode tab 42, and prevents current from flowing through the power storage device 100. Specifically, when the pressure in the case 1 rises, the pressure acting on the lower surfaces of the energization plate 20 and the deformation plate rises. On the other hand, atmospheric pressure acts on the upper surface of the deformation plate 30. For this reason, when the internal pressure of the case 1 rises and reaches a predetermined value, the energizing plate 20 connected to the central portion 32 of the deformable plate 30 breaks starting from the mechanically fragile groove 20a. And the deformation | transformation board 30 inverts and changes to a convex state upwards. As a result, the energization path connecting the energization plate 20 and the deformation plate 30 is interrupted, and the electrode assembly 3 (negative electrode) and the negative electrode terminal 7 are brought out of electrical conduction.

  Advantages of the power storage device 100 will be described. As described above, the sealing plug 15 has a structure in which the metal portion 16 is covered with the resin portion 14. Metals have extremely low moisture permeability compared to resins. Therefore, the amount of moisture passing through the inside of the sealing plug 15 can be reduced by using the sealing plug 15. The movement path of moisture from the external space of power storage device 100 into space 51 can be reliably reduced. Further, by covering the metal part 16 with the resin part 14, the resin part 14 of the sealing plug 15 comes into contact with the through hole 97. It is possible to prevent a gap from being generated between the sealing plug 15 and the through hole 97. If the metal part is not covered with the resin part (in the case of a sealing plug formed only of metal), it is necessary to weld the sealing plug to the through hole in order to close the gap between the sealing plug and the through hole. Become. The welding heat may adversely affect other members of the power storage device.

  The resin portion 14 of the sealing plug 15 is welded to the wall surface of the through hole 97 and the caulking portion 96. Therefore, the sealing plug 15 and the negative electrode terminal 7 (the through hole 97, the caulking portion 96) are in close contact with each other without any gap, and it is possible to reliably prevent moisture from moving from the external space into the space 51. Further, the surface of the metal part 16 is exposed from the resin part 14. When the resin part 14 is welded to the negative electrode terminal 7, the resin part 14 can be easily melted by heating the metal part 16.

  The material of the metal part 16 and the material of the negative electrode terminal 7 are the same (copper). Therefore, metal corrosion is suppressed from occurring at the contact portion between the sealing plug 15 and the negative electrode terminal 7. Moreover, if the material of the metal part 16 is the same as the material of the negative electrode terminal 7, both can be welded easily.

(Second embodiment)
The power storage device 200 will be described with reference to FIG. The power storage device 200 is a modification of the power storage device 100, and the structure of the current interrupt device 210 is different from the current interrupt device 10 of the power storage device 100. With respect to the power storage device 200, the same components as those of the power storage device 100 may be denoted by the same reference numerals as those of the power storage device 100, and description thereof may be omitted.

  The current interrupting device 210 includes a second deformable plate 40 in addition to the deformable plate 30. In the following description, the first deformation plate 30 and the second deformation plate 40 are referred to. The second deformation plate 40 is disposed on the side opposite to the first deformation plate 30 with respect to the energization plate 20. That is, the energization plate 20 is disposed between the first deformation plate 30 and the second deformation plate 40. An end 40 e of the second deformation plate 40 is fixed to the energization plate 20. Specifically, the end 40 e of the second deformation plate 40 is welded to the end 20 e of the energization plate 20.

  An insulating protrusion 45 is provided on the current plate 20 side of the second deformation plate 40. The protrusion 45 is fixed to the central portion 40 c of the second deformation plate 40 and protrudes toward the energization plate 20. The protrusion 45 faces the central portion 20 c of the energization plate 20. More specifically, the protrusion 45 is opposed to a range surrounded by the groove 20a of the energization plate 20.

  When the internal pressure of the case 1 is less than or equal to a predetermined value, a gap is provided between the protrusion 45 and the energizing plate 20. When the internal pressure of the case 1 exceeds a predetermined value, the second deformable plate 40 is deformed toward the energizing plate 20. That is, the protrusion 45 moves toward the central portion 20 c of the energization plate 20. The protrusion 45 comes into contact with the energizing plate 20, and the energizing plate 20 is broken starting from the groove 20a. The current-carrying plate 20 and the first deformation plate 30 become non-conductive, and the negative electrode terminal 7 and the negative electrode become non-conductive (see also FIG. 1). The space 50a between the energizing plate 20 and the first deformable plate 30 communicates with the space 50b between the energizing plate 20 and the second deformable plate 40 through the vent hole 20b. Therefore, when the protrusion 45 moves toward the energization plate 20, the pressure in the space 50a increases, and the first deformation plate 30 can be deformed upward.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Case 4: Positive terminal (contact prevention structure)
16: Negative terminal 20: Current interruption device 24: Electrode assembly 100: Power storage device

Claims (9)

Case and
An electrode assembly housed in the case and comprising a positive electrode and a negative electrode;
An electrode terminal passing through the inside and outside of the case and having a through hole;
It is accommodated in the case and fixed to the electrode terminal, and when the pressure in the case exceeds a predetermined value, the electrode terminal and the positive electrode or the negative electrode are changed from a conductive state to a non-conductive state. A current interrupting device to switch,
A sealing stopper sealing the through hole, and
The sealing plug is
It has a metal part and a resin part provided on the surface of the metal part,
Including an insertion portion inserted into the through-hole, and an expansion portion located outside the through-hole and larger in size than the through-hole,
The power storage device, wherein the resin portion is provided around the insertion portion around the insertion portion .   The power storage device according to claim 1, wherein the resin portion is welded to the electrode terminal in the through hole. The power storage device according to claim 1, wherein the resin portion is provided around the insertion portion on a surface of the extension portion on the through-hole side. Case and
An electrode assembly housed in the case and comprising a positive electrode and a negative electrode;
An electrode terminal passing through the inside and outside of the case and having a through hole;
It is accommodated in the case and fixed to the electrode terminal, and when the pressure in the case exceeds a predetermined value, the electrode terminal and the positive electrode or the negative electrode are changed from a conductive state to a non-conductive state. A current interrupting device to switch,
A sealing stopper sealing the through hole, and
The sealing plug is
It has a metal part and a resin part provided on the surface of the metal part,
Including an insertion portion inserted into the through-hole, and an expansion portion located outside the through-hole and larger in size than the through-hole,
The power storage device, wherein the resin portion is provided around the insertion portion on a surface of the extension portion on the through-hole side. The power storage device according to claim 3 or 4 , wherein the resin portion is welded to the electrode terminal outside the through hole. The power storage device according to claim 1, wherein the metal part is welded to the electrode terminal. The power storage device according to any one of claims 1 to 6 , wherein the metal part includes the same element as an element constituting a material of the electrode terminal. The power storage device according to claim 1, wherein the metal part is a copper-based material. Said power storage device, a power storage device according to any one of claims 1 to 8 is a secondary battery.

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