JP6194822B2 - Current interrupt device and power storage device including the same - Google Patents

Description

  The present specification relates to a current interrupt device and a power storage device including the current interrupt device.

  The power storage device may be provided with a current interrupt device that interrupts energization when overcharge or the like occurs (for example, Patent Document 1). The current interrupting device is provided on an energization path that connects the electrode assembly and the terminal. When the internal pressure in the case exceeds the set pressure due to overcharging or the like, the current interrupt device is activated and the energization path is interrupted. As a result, the current flowing through the energization path is interrupted.

JP 2013-225500 A

  In the current interrupt device of Patent Document 1, a support member (holder) that supports a current-carrying plate (current collector) with respect to a terminal is provided. A through hole is formed in the energizing plate, and a boss that penetrates the through hole of the energizing plate is formed in the support member. The energizing plate and the support member are fixed by caulking the boss of the support member. Since the support member is directly fixed to the energizing plate using heat caulking, the number of parts can be reduced and the structure can be simplified. However, in this current interrupting device, the support member and the energizing plate are directly fixed by heat caulking, so that heat generated during the heat caulking is conducted to the energizing plate. If the heat conducted to the current-carrying plate is conducted to the terminal side, the characteristics of the current interrupting device may change due to the heat. For example, the current interrupting device is designed to operate when the internal pressure in the case exceeds the set pressure, but the operating pressure of the current interrupting device may change due to the effect of heat conducted from the energizing plate to the terminal side. There is. This specification provides the technique which can suppress the characteristic change of the electric current interruption apparatus by the heat | fever of a heat caulking, fixing an electricity supply board and a supporting member using heat caulking.

  The current interrupt device disclosed in the present specification is provided on an energization path that connects a terminal provided in a case and an electrode assembly accommodated in the case, and the terminal and the electrode when the internal pressure in the case exceeds a set pressure. The current flowing to and from the assembly is cut off. The current interrupting device includes a first energizing plate electrically connected to the terminal, a second energizing plate disposed opposite to the first energizing plate and electrically connected to the electrode assembly, and insulating properties. And a support member fixed to the second energizing plate and supporting the second energizing plate with respect to the terminal. The center part of the 1st electricity supply board and the center part of the 2nd electricity supply board are being fixed. The second energization plate breaks when the internal pressure in the case exceeds the set pressure, and interrupts the current flowing between the terminal and the electrode assembly. A through hole is formed in the outer peripheral portion of the second energization plate. The support member has a heat caulking boss that is inserted into the through hole of the second energization plate and fixes the support member to the second energization plate. In the cross section in which the center of the second current plate and the through hole are connected and the second current plate is cut along a plane perpendicular to the surface of the second current plate, the thermal resistance of the second current plate is larger than that of the through hole. The part side is smaller than the center part side than the through hole.

  In said electric current interruption apparatus, the thermal resistance of the 2nd electricity supply board is made smaller in the direction of an outer peripheral part side than a through-hole than the direction of the center part side rather than the through-hole. For this reason, the heat generated when the support member and the second current plate are fixed by heat caulking is transmitted from the terminal side (that is, the central portion side of the through hole) to the electrode assembly side (the outer peripheral portion side of the through hole). It becomes easy to be done. As a result, it is possible to suppress changes in the characteristics of the current interrupting device due to the heat of the caulking.

  According to the present invention, it is possible to suppress a change in the characteristics of the current interrupting device due to the heat of the heat caulking while fixing the current-carrying plate and the support member using the heat caulking.

Sectional drawing of an electrical storage apparatus. The bottom view of the fracture | rupture board of an electric current interruption apparatus. Sectional drawing when an electric current interruption apparatus is cut | disconnected by the III-III line of FIG. The figure which shows the electric current interruption apparatus when the internal pressure in a case rises and the electricity supply between a terminal and an electrode is interrupted | blocked (sectional drawing corresponding to FIG. 3). The figure for demonstrating the heat crimping process for fixing the fracture | rupture board and holder of an electric current interruption apparatus. The bottom view of the fracture | rupture board which concerns on a modification. The bottom view of the fracture | rupture board which concerns on another modification. The figure which shows the other example of an electric current interruption apparatus.

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

(Characteristic 1) The current interrupting device disclosed in this specification is disposed in a space surrounded by the first current plate, the second current plate, and the support member, and the outer periphery of the first current plate and the outer periphery of the second current plate. And a sealing member that seals between the portions. According to such a configuration, heat transmitted to the seal member can be suppressed, and a change in characteristics of the current interrupt device can be suppressed.

(Characteristic 2) In the current interrupting device disclosed in this specification, a plurality of through holes may be formed around the central portion of the energizing plate. A plurality of heat caulking bosses may be formed corresponding to the plurality of through holes. When the second energization plate is viewed in plan, the second energization plate is connected to the plurality of through holes on the outer peripheral side and the first region which is the region inside the first boundary line connected to the plurality of through holes on the inner peripheral side. You may have the 2nd field outside the 2nd boundary line to do. The center part joined to the 1st electricity supply board may be located in the 1st field. The plate thickness in the first region of the second energization plate may be smaller than the plate thickness in the second region of the second energization plate. According to such a structure, it is suppressed that the heat of heat caulking is effectively transmitted to the terminal side, and the characteristic change of the current interrupting device can be suppressed.

(Characteristic 3) The current interrupting device disclosed in the present specification further includes a deformation plate that receives the pressure of the internal space of the case on one surface and receives the pressure of the space isolated from the internal space of the case on the other surface. You may have. The second energizing plate may be disposed on the other surface side of the deforming plate and may be disposed between the deforming plate and the first energizing plate. When the pressure in the internal space of the case exceeds the set value, the second deformable plate may be broken by the deformable plate being deformed to the second energizing plate side. The deformation plate may be fixed to the first region of the second energization plate. According to such a structure, it is suppressed that the heat | fever of a heat crimping is transmitted to a deformation | transformation board, and the characteristic change of an electric current interruption apparatus can be suppressed.

(Feature 4) In the current interrupt device disclosed in this specification, the cross-sectional area of the through hole may be smaller on the terminal side than on the non-terminal side. The heat caulking boss may be in close contact with the inner surface of the through hole by heat caulking. According to such a configuration, the second energization plate and the support member are fixed in close contact with each other, and the second energization plate can be stably supported. Further, the second energization plate and the support member are in close contact with each other, and much heat of the caulking is transmitted to the second energization plate, but the heat transmitted to the second energization plate can be released to the electrode assembly side. For this reason, the characteristic change of an electric current interruption apparatus can be suppressed.

  Hereinafter, the power storage device 100 of the embodiment will be described. The power storage device 100 is a lithium ion secondary battery that is a type of secondary battery. As shown in FIG. 1, the power storage device 100 includes a case 4, an electrode assembly 2, a negative electrode terminal 30 and a positive electrode terminal 10, and a current interrupt device 70. The case 4 is made of metal and has a substantially rectangular parallelepiped shape. Inside the case 4, the electrode assembly 2 and the current interrupt device 70 are accommodated. In addition, an electrolytic solution is injected into the case 4. A negative electrode terminal 30 and a positive electrode terminal 10 are attached to the upper surface 4 a of the case 4. That is, through holes 4 b and 4 c are formed in the upper surface 4 a of the case 4. The negative terminal 30 is attached to the through hole 4b, and the positive terminal 10 is attached to the through hole 4c. An insulating first seal member 42 is disposed in the through hole 4b. An insulating second seal member 22 is disposed in the through hole 4c. The shape of the case 4 is not limited, and may be, for example, a cylindrical shape, a rectangular parallelepiped shape, or a sheet shape formed of a film.

  The negative electrode terminal 30 includes an external nut 36, an internal nut 32, and a bolt 34. The external nut 36 is used for connection between the negative electrode terminal 30 and a negative electrode wiring (not shown). The inner nut 32 is attached to the first seal member 42. A part of the inner nut 32 passes through the through hole 4b. The bolt 34 is fastened to the internal nut 32. A third seal member 40 is interposed between the bolt 34 and the case 4. The negative electrode terminal 30 is insulated from the case 4 by the seal members 40 and 42. The inner nut 32 is electrically connected to the negative electrode lead 44 via the current interrupt device 70 and the connection terminal 72. The negative electrode lead 44 is insulated from the case 4 by the first seal member 42. The negative electrode terminal 30 is energized with the negative electrode of the electrode assembly 2 via the current interrupt device 70, the connection terminal 72, and the negative electrode lead 44. The current interrupt device 70 will be described later.

  The positive terminal 10 includes an external nut 16, an internal nut 12, and a bolt 14. The external nut 16 is used for connection between the positive terminal 10 and the positive wiring (not shown). The inner nut 12 is attached to the second seal member 22. A part of the inner nut 12 passes through the through hole 4c. The bolt 14 is fastened to the inner nut 12. A fourth seal member 20 is interposed between the bolt 14 and the case 4. The positive electrode terminal 10 is insulated from the case 4 by the seal members 20 and 22. A positive electrode lead 24 is fixed to the inner nut 12. The inner nut 12 and the positive electrode lead 24 are electrically connected. The positive electrode lead 24 is insulated from the case 4 by the second seal member 22. The positive electrode terminal 10 is energized with the positive electrode of the electrode assembly 2 via the positive electrode lead 24.

(Electrode assembly)
The electrode assembly 2 includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. Illustration of the positive electrode, the negative electrode, and the separator is omitted. The negative electrode has a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector. The negative electrode has a negative electrode current collecting tab 46 at its end. A negative electrode active material layer is not applied to the negative electrode current collecting tab 46. The positive electrode has a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode has a positive electrode current collecting tab 26 at its end. The positive electrode current collecting tab 26 is not coated with a positive electrode active material layer. Note that there are no particular limitations on materials (eg, active material, binder, and conductive additive) included in the active material layer, and materials that are used for electrodes of known power storage devices and the like can be used.

Here, for the positive electrode current collector, for example, aluminum (Al), nickel (Ni), titanium (Ti), stainless steel, or a composite material or alloy thereof can be used. In particular, aluminum or a composite material or alloy containing aluminum is preferable. The positive electrode active material may be any material that allows lithium ions to 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 , LiCoO ₂ , LiNi _0.8 Co _0.15 Al _0.05 O ₂ , Li ₂ MnO ₂ , LiMn ₂ O _{4 and 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. The positive electrode active material is applied to the positive electrode current collector together with a conductive material, a binder and the like as necessary.

  On the other hand, as the negative electrode current collector, aluminum, nickel, copper (Cu), or a composite material or alloy thereof can be used. In particular, copper or a composite material or alloy containing copper is preferable. As the negative electrode active material, a material into which lithium ions can be inserted and removed can be 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. A negative electrode active material is apply | coated to a negative electrode collector with a electrically conductive material, a binder, etc. as needed.

  Note that the separator can be made of an insulating porous material. 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 non-aqueous electrolytic solution in which a supporting salt (electrolyte) is dissolved in a non-aqueous 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.

(Current interrupter)
With reference to FIGS. 2-4, the electric current interruption apparatus 70 is demonstrated. The current interrupt device 70 is disposed on a current path between the negative electrode terminal 30 and the negative electrode current collecting tab (negative electrode) 46. In addition, the electric current interruption apparatus 70 may be arrange | positioned on the electricity supply path | route of a positive electrode and the positive electrode terminal 10, and may be arrange | positioned to both. 3 and 4, the illustration of the seal member 42 interposed between the negative electrode terminal 30 and the case 4 is omitted.

  As shown in FIG. 3, the current interrupt device 70 includes a metal first reversing plate 84, a metal breaking plate 88, a metal second reversing plate 90, and an insulating support member 92. Yes. The support member 92 is made of a thermoplastic resin (for example, PPS). The support member 92 is formed in a cylindrical shape, and a space for accommodating the lower end portion 32a of the internal nut 32 and the second reversing plate 90 is formed inside thereof. The upper surface 92b of the support member 92 is in contact with the case 4 (see FIG. 1). At the upper end of the support member 92, a protruding piece 92e protruding inward is formed. The protruding piece 92e is in contact with the upper surface of the lower end 32a of the internal nut 32. A heat caulking boss 92 a is formed on the lower surface 92 c of the support member 92. The heat caulking bosses 92 a are respectively provided at the four corners of the lower surface 92 c of the support member 92. As will be described later, the fracture plate 88 is fixed to the support member 92 by a heat caulking boss 92a. When the fracture plate 88 is fixed to the lower surface 92c of the support member 92, the lower end portion 32a and the second reversing plate 90 are accommodated in the support member 92, and the protruding piece 92e of the support member 92 contacts the upper surface of the lower end portion 32a. As a result, the support member 92 supports the first reversing plate 82 and the breaking plate 88 in a stacked state, and the current interrupting device 70 is fixed to the inner nut 32. Since the upper surface 92 b of the support member 92 contacts the case 4, the positions of the internal nut 32, the first reversing plate 82, and the fracture plate 88 with respect to the case 4 are positioned by the support member 92.

  The first inversion plate 84 is a circular plate material and is fixed to the lower surface of the fracture plate 88. Since the fracture plate 88 is fixed and supported by the support member 92, the first reverse plate 84 is also supported by the support member 92. An insulating protrusion 86 is provided on the upper surface of the first reversing plate 84, and the protrusion 86 is located at the center of the first reversing plate 84. The protrusion 86 protrudes upward toward the fracture plate 88. In the state shown in FIG. 3, a gap is formed between the protrusion 86 and the central portion 88 b of the breaking plate 88. The pressure in the space in the case 4 acts on the lower surface of the first reversing plate 84, and the pressure in the space 94 between the first reversing plate 84 and the fracture plate 88 acts on the upper surface of the first reversing plate 84. To do. Since the space 94 is isolated from the space in the case 4, when the pressure in the space in the case 4 increases, the pressure acting on the upper surface and the lower surface of the first reversing plate 84 will be different.

  The fracture plate 88 is a rectangular plate material, and is disposed between the first reverse plate 84 and the second reverse plate 90. That is, the upper surface of the fracture plate 88 faces the second reversal plate 90, while the lower surface faces the first reversal plate 84. A connection terminal 72 is connected to a part of the outer edge of the fracture plate 88 (see FIG. 3). A groove 88 a is formed at the center of the lower surface of the fracture plate 88. As shown in FIG. 2, the groove 88 a is formed in a circular shape when viewed from the bottom. In addition, as shown in FIG. 3, the cross-sectional shape of the groove 88a is a triangular shape that protrudes upward. By forming the groove 88a, the mechanical strength of the fracture plate 88 at the position where the groove 88a is formed is lower than the mechanical strength of the fracture plate 88 at a position other than the groove 88a. The fracture plate 88 is divided into a central part 88b surrounded by the groove part 88a and an outer peripheral part (88e to 88g) located on the outer peripheral side of the groove part 88a by the groove part 88a.

  As shown in FIGS. 2 and 3, the outer peripheral portion (88e to 88g) of the fracture plate 88 includes a first outer peripheral portion 88e adjacent to the central portion 88b, a second outer peripheral portion 88f adjacent to the first outer peripheral portion 88e, A third outer peripheral portion 88g adjacent to the second outer peripheral portion 88f is provided. The first outer peripheral portion 88e is located outside the central portion 88b and surrounds the central portion 88b. The plate thickness of the first outer peripheral portion 88e is the same as the plate thickness of the central portion 88b. The second outer peripheral portion 88f is located outside the first outer peripheral portion 88e and surrounds the first outer peripheral portion 88e. The plate thickness t1 of the second outer peripheral portion 88f is thicker than the plate thickness of the first outer peripheral portion 88e. The third outer peripheral portion 88g is located outside the second outer peripheral portion 88f and surrounds the second outer peripheral portion 88f. The plate thickness t2 of the third outer peripheral portion 88g is thicker than the plate thickness t1 of the second outer peripheral portion 88f (t2> t1). A through hole 88d is formed at the boundary between the second outer peripheral portion 88f and the third outer peripheral portion 88g. More specifically, the through holes 88d are four corners of the second outer peripheral portion 88f and are disposed at positions corresponding to the heat caulking bosses 92a of the support member 92. The boundary line between the second outer peripheral portion 88f and the third outer peripheral portion 88f is in contact with the through hole 88d on the outer peripheral side of the through hole 88d.

  As shown in FIG. 3, the through-hole 88d penetrates from the upper surface to the lower surface of the fracture plate 88, and its cross-sectional diameter is D1. The heat caulking boss 92a of the support member 92 is inserted into the through hole 88d. The heat caulking boss 92a is in close contact with the inner surface of the through hole 88d by heat caulking. Further, the diameter of the lower end portion of the heat caulking boss 92a is D2 (> D1) by the heat caulking process. For this reason, the fracture plate 88 is fixed to the support member 92 by heat caulking the thermal caulking boss 92a to the through hole 88d.

The plate thickness t1 of the second outer peripheral portion 88f is made thinner than the plate thickness t2 of the third outer peripheral portion 88g. Therefore, the outer peripheral side region (Figure 2 of the through-hole 88d, points contour line of the straight line and the through-hole 88d connecting the center O ₂ of the center O ₁ and the through hole 88d of the central portion 88b intersect at an outer peripheral side P1 In the region including the through hole 88d, the through hole 88d is in contact with the thick third outer peripheral portion 88g. On the other hand, (in FIG. 2, the region including the center O ₁ and the center O ₂ and the point P2 contour line of the straight line and the through-hole 88d intersect at an inner peripheral side connecting) area of the inner peripheral side of the through hole 88d in the through The hole 88d is in contact with the second outer peripheral portion 88f having a small plate thickness. That is, in this embodiment, the through hole 88d is in contact with the third outer peripheral portion 88g in a region where the central angle on the outer peripheral side of the through hole 88d is approximately 90 °, and the central angle on the inner peripheral side of the through hole 88d is It is in contact with the second outer peripheral portion 88f in a region of approximately 270 °. Therefore, knot the center O ₂ of the center O ₁ and the through hole 88d of the central portion 88b, and, in a cross section obtained by cutting the rupture plate 88 in a plane perpendicular to the surface of the rupture plate 88 (the cross-section shown in FIG. 3), The thermal resistance of the fracture plate 88 is smaller on the outer peripheral side than the through hole 88d than on the central side than the through hole 88d. 2 and 3, the central portion 88b is located inside the four through holes 88d, and the first reversing plate 84 is fixed to the second outer peripheral portion 88f inside the four through holes 88d. Yes.

  The second reversing plate 90 is a circular plate material and is disposed above the fracture plate 88. In the state shown in FIG. 3, the central portion of the second reversing plate 90 is convex downward, and is fixed to the central portion 88 b of the breaking plate 88. Specifically, the central portion of the second reversing plate 90 is joined to the central portion 88b of the fracture plate 88 by welding. Moreover, the outer peripheral part of the 2nd inversion board 90 is joined to the lower end part 32a of the internal nut 32 by welding. A welded portion between the second reverse plate 90 and the internal nut 32 is formed over the entire circumference of the outer peripheral portion of the second reverse plate 90. As apparent from the above, the negative electrode terminal 30 is connected to the electrode assembly 2 via the second reversing plate 90, the fracture plate 88, the connection terminal 72, and the negative electrode lead 44. A space 98 is formed between the upper surface of the second reversing plate 90 and the lower surface of the internal nut 32, and the space 98 is isolated from the space in the case 4. An insulating member 82 and a seal member 89 are disposed between the second reversing plate 90 and the fracture plate 88. A support member 92 is disposed outside the seal member 89. The insulating member 82 is a ring-shaped member and is in contact with the outer peripheral portion of the second reversing plate 90 and the outer peripheral portion of the fracture plate 88 to insulate them. The seal member 89 contacts the lower end portion 32a of the internal nut 32 and the outer peripheral portion of the fracture plate 88, and seals between the two. As a result, the space 96 between the second reversing plate 90 and the breaking plate 88 is hermetically sealed from the space in the case 4. For the seal member 89, for example, a known O-ring or the like can be used.

  The second reversing plate 90 may be sandwiched between the insulating member 82 and the inner nut 32 in a state where the second reversing plate 90 is biased in a direction away from the fracture plate 88. By energizing the breaking plate 88, the second reversing plate 90 can be moved away from the breaking plate 88 when the breaking plate 90 breaks at the groove 88a.

  In the power storage device 100 described above, in the state illustrated in FIG. 3, the negative electrode terminal 30 and the negative electrode current collecting tab 46 (negative electrode) are energized, and the positive electrode terminal 10 and the positive electrode current collecting tab 26 (negative electrode) are energized. ing. For this reason, the negative electrode terminal 30 and the positive electrode terminal 10 are energized. When the internal pressure in the case 4 rises and exceeds a predetermined value set in advance, as shown in FIG. 4, the fracture plate 88 breaks at the groove 88a, and the outer peripheral portion (88e to 88g) of the fracture plate 88 and the second The energization path between the reversing plates 90 (internal nuts 32) is interrupted. That is, when the internal pressure in the case 4 increases, the pressure acting on the lower surface of the first reversing plate 84 increases (state shown in FIG. 3). Since the space 94 is isolated from the space in the case 4, the pressure acting on the upper surface of the first reversing plate 84 (that is, the pressure in the space 94) is not easily affected by the pressure increase in the space in the case 4. For this reason, when the internal pressure in the case 4 exceeds a predetermined value (set pressure), the first reversing plate 84 is reversed to change from a downward convex state to an upward convex state. When the first reversing plate 84 is reversed, the protrusion 86 of the first reversing plate 84 collides with the central portion 88b of the breaking plate 88, and the breaking plate 88 is broken at the groove 88a. Then, the second reversing plate 90 is also reversed in accordance with the displacement of the first reversing plate 84, and the second reversing plate 90, the central portion 88b of the breaking plate 88, and the first reversing plate 84 are displaced upward (in FIG. 4). State). As a result, the energization path connecting the fracture plate 88 and the second reversing plate 90 is interrupted, and the energization between the electrode assembly 2 and the negative electrode terminal 30 is interrupted.

  In the power storage device 100 of the present embodiment, the fracture plate 88 is fixed to the lower surface 92c of the support member 92 using heat caulking. That is, when manufacturing the current interrupt device 70, first, the inner nut 32, the second reversing plate 90, the fracture plate 88, the first reversing plate 84, the insulating member 82, and the seal member 89 are combined to form a subassembly. Next, the sub-assembled component is fixed to the support member 92. Specifically, as shown in FIG. 5, the sub-assembly is made so that the lower end portion 32 a of the inner nut 32, the second reversing plate 90, the insulating member 82, and the seal member 89 are accommodated inside the support member 92. The inserted part is inserted into the support member 92, and the protruding piece 92e of the support member 92 is brought into contact with the upper surface of the lower end portion 32a. In this state, the lower surface 92c of the support member 92 is in contact with the upper surface of the breaker plate 88, and the heat caulking boss 92a (before deformation) of the support member 92 is inserted into the through hole 88d of the breaker plate 88. (The state of FIG. 5). Next, the heat caulking boss 92 a inserted into the through hole 88 d is heated by the heater chip 200. As a result, the heat caulking boss 92d is thermally deformed and changes to the state shown in FIG. That is, the heat caulking boss 92a is brought into close contact with the inner surface of the through hole 88d by thermal deformation, and the lower end portion thereof is larger than the diameter D1 of the through hole 88d. As a result, the fracture plate 88 is fixed to the lower surface 92 c of the support member 92.

  Here, when the caulking boss 92a is caulked, the heater chip 200 applies heat to the caulking boss 92a. For this reason, heat is transmitted from the heat caulking boss 92 a to the fracture plate 88. In the fracture plate 88 of the present embodiment, a third outer peripheral portion 88g is provided on the outer peripheral side of the through hole 88d, and a second outer peripheral portion 88f is provided on the inner peripheral side of the through hole 88d. As described above, the plate thickness t2 of the third outer peripheral portion 88g is thicker than the plate thickness t1 of the second outer peripheral portion 88f, and the thermal resistance on the outer peripheral side of the through hole 88d is smaller than the thermal resistance on the inner peripheral side of the through hole 88d. It has become. For this reason, the heat transmitted from the heat caulking boss 92a to the fracture plate 88 is made easier to flow from the second outer peripheral portion 88f side to the third outer peripheral portion 88g side. As a result, the heat transmitted to the central portion 88b side of the fracture plate 88 can be reduced. Thereby, it can suppress that the characteristic of the electric current interruption apparatus 70 changes. For example, when the amount of heat transmitted to the central portion 88b side of the fracture plate 88 increases, the sealing performance of the seal member 89 may deteriorate due to the heat. When the sealing performance of the seal member 89 deteriorates, the space 96 and the space in the case 4 communicate with each other, and the operating pressure of the current interrupt device 70 may change. In the present embodiment, since the amount of heat transmitted to the central portion 88b side of the breaker plate 88 can be reduced, the deterioration of the seal member 89 can be suppressed and the characteristic change of the current interrupt device 70 can be suppressed.

  As is clear from the above description, in the power storage device 100 of the present embodiment, heat generated during thermal caulking can be suppressed from being transmitted to the central portion 88b side of the fracture plate 88. For this reason, the characteristic change of the electric current interruption apparatus 70 can be suppressed. As a result, the current interrupting device 70 can be appropriately operated while a simple configuration is achieved by fixing the fracture plate 88 to the support member 92 using thermal caulking.

  Finally, the correspondence relationship between the above-described embodiment and the description of the claims will be described. The second reversing plate 90 is an example of a “first energizing plate”, and the fracture plate 88 is an example of a “second energizing plate”.

  As mentioned above, although the specific example of the technique disclosed by this specification was demonstrated in detail, this is only an illustration and does not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  For example, in the above-described embodiment, the thermal resistance is adjusted between the inner peripheral side and the outer peripheral side of the through hole 88d by providing the second outer peripheral portion 88f and the third outer peripheral portion 88g in the fracture plate 88. The technology disclosed in the above is not limited to such an example. For example, the thermal resistance at the point P1 (see FIG. 2) on the outer peripheral side of the through hole 88d only needs to be smaller than the thermal resistance at the point P2 (see FIG. 2) on the inner peripheral side of the through hole 88d. For this reason, the boundary between the second outer peripheral portion 88f having the plate thickness t1 and the third outer peripheral portion 88e having the plate thickness t2 (> t1) is not limited to the example illustrated in FIG. For example, like the fractured plate 188 shown in FIG. 6, most of the through hole 188d in the circumferential direction may be in contact with the third outer peripheral portion 188g. In this case, it is possible to further promote the transfer of heat at the time of heat caulking to the outer peripheral side of the fracture plate 188. Furthermore, the boundary between the second outer peripheral portion having the plate thickness t1 and the third outer peripheral portion having the plate thickness t2 (> t1) is not limited to the example of FIGS. 2 and 6, and various forms can be adopted. For example, as shown in FIG. 7, the boundary between the second outer peripheral portion and the third outer peripheral portion can be arbitrarily set in a region between the boundary line B1 and the boundary line B2. Moreover, it is not necessary to provide the boundary of both in a straight line, and you may provide in a curved line. Even if the boundary between the second outer peripheral portion and the third outer peripheral portion is arbitrarily set, if the boundary is located between the boundary lines B1 and B2, the region inside the boundary line B1 (the first term in the claims) In the example of the region, the thickness of the fracture plate 288 is t1, and in the region outside the boundary line B2 (second region in the claims), the thickness of the fracture plate 288 is t2. As a result, heat can be prevented from being transmitted to the central portion 288b of the fracture plate 288.

  In the above-described embodiment, the current interrupting device 70 includes the three plates of the first reversing plate 84, the breaking plate 88, and the second reversing plate 90, but the configuration of the current interrupting device is such a configuration. Not limited to. For example, like the current interrupt device 170 shown in FIG. 8, the current interrupt device 170 may be configured by two plate members of the fracture plate 88 and the second reversing plate 90.

  The technical elements described in this specification or the 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: Electrode assembly 4: Case 10: Positive electrode terminal 24: Positive electrode lead 12, 32: Internal nut 14, 34: Bolt 16, 36: External nut 30: Negative electrode terminal 44: Negative electrode lead 70: Current interruption device 84: First Reverse plate 88: Breaking plate 90: Second reverse plate 100: Power storage device

Claims (6)

Provided on a current-carrying path connecting a terminal provided in the case and the electrode assembly accommodated in the case, and flows between the terminal and the electrode assembly when an internal pressure in the case exceeds a set pressure A current interrupting device for interrupting current,
A first current plate electrically connected to the terminal;
A second energization plate disposed opposite to the first energization plate and electrically connected to the electrode assembly;
A support member that has insulating properties and is fixed to the second energization plate and supports the second energization plate with respect to the terminal,
The central portion of the first current plate and the central portion of the second current plate are fixed,
The second energization plate breaks when an internal pressure in the case exceeds a set pressure, and interrupts a current flowing between the terminal and the electrode assembly,
A through hole is formed in the outer peripheral portion of the second energization plate,
The support member is inserted into a through hole of the second current plate, and has a heat caulking boss that fixes the support member to the second current plate,
In a cross section in which the second current plate is cut by a plane that connects the central portion of the second current plate and the through hole and is orthogonal to the surface of the second current plate, the thermal resistance of the second current plate is The current interrupting device, wherein the outer peripheral side of the through hole is smaller than the central side of the through hole.   The current interrupting device is disposed in a space surrounded by the first energizing plate, the second energizing plate, and the support member, and between the outer peripheral portion of the first energizing plate and the outer peripheral portion of the second energizing plate. The current interrupting device according to claim 1, further comprising: a sealing member that seals. A plurality of the through holes are formed around the central portion of the energization plate,
A plurality of the thermal caulking bosses are formed corresponding to the plurality of through holes,
When the second energization plate is viewed in plan, the second energization plate is formed in a first region that is an area inside a first boundary line that is connected to the plurality of through holes on the inner peripheral side, and the plurality of through holes. Having a second region outside the second boundary line connected on the outer peripheral side;
In the first region, a central portion to be joined to the first current plate is located,
The current interrupting device according to claim 1 or 2, wherein a plate thickness in the first region of the second energization plate is thinner than a plate thickness in the second region of the second energization plate. The current interrupt device further includes a deformation plate that receives the pressure of the internal space of the case on one surface and receives the pressure of the space isolated from the internal space of the case on the other surface,
The second energization plate is disposed on the other surface side of the deformation plate, and is disposed between the deformation plate and the first energization plate,
When the pressure in the internal space of the case exceeds a set value, the deforming plate is deformed to the second energizing plate side, whereby the second energizing plate is broken,
The current interrupting device according to claim 3, wherein the deformation plate is fixed to the first region of the second energization plate. The cross-sectional area of the through hole is such that the terminal side is smaller than the non-terminal side,
The current interrupting device according to claim 1, wherein the thermal caulking boss is in close contact with the inner surface of the through hole by thermal caulking processing.   An electrical storage apparatus provided with the electric current interruption apparatus as described in any one of Claims 1-5.

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