JP2015095370A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device in which a terminal is caulked and fixed to a case, the device being designed to prevent decrease in sealing force of a sealing member arranged between the terminal and the case even when a long period of time passes, and to prevent decrease in load of caulking in a fixing part of the terminal.SOLUTION: A power storage device 100 comprises a case 1, an electrode assembly 3, terminals 5, 7, and a current cutout device 30. The terminal 5 has a cylindrical part 14, a bottom base part 15, and a fixing part 16 that caulk-fixes the terminal 5 to a terminal wall 9 by bending radially outside the other end of the cylindrical part 14. An O ring 19, which seals the space between the terminal 5 and terminal wall 9 by coming into contact with the terminal 5 and terminal wall 9, is arranged in a range where the terminal 5 and the terminal wall 9 face and in a range occupied by the fixing part 16, as viewed from above. In the space between the terminal 5 and the terminal wall 9 and further inside the case than the position of the O ring 19, an annular insulation member 36 is arranged. The O ring 19 is in contact with the insulation member 36 as well.

Description

  The technology disclosed in this specification relates to a power storage device including a current interrupt device.

  In the technical field of power storage devices, the development of current interrupting devices that cut off the current flowing between the terminals (positive terminal and negative terminal) proceeds when the power storage device is overcharged or when a short circuit occurs internally. It has been. The current interrupt device is disposed between the terminal and the current collector (positive electrode current collector or negative electrode current collector). Patent Document 1 discloses a current interrupting device in which a conductive plate connected to a current collector and a deformed plate connected to a terminal are joined. When the pressure in the power storage device increases, the deformation plate separates from the conduction plate, and the current between the terminal and the conduction plate is interrupted.

JP 2012-119183 A

  In the power storage device of Patent Document 1, the terminal communicates with the inside and outside of the case through an opening formed in the upper wall of the case. A resin seal member is disposed between the terminal and the case upper wall, and seals between the terminal and the case upper wall. The terminal is caulked and fixed to the upper wall of the case by bending one end of the terminal outside the case outward in the radial direction (hereinafter, the caulked portion of the terminal is referred to as a fixing portion). When the terminal is caulked and fixed to the case upper wall, the sealing member is sandwiched between the terminal and the case upper wall by the caulking load. For this reason, a constant load (caulking load) is constantly applied to the seal member from the fixed portion, and the seal member may creep-deform after a long period of time. When the seal member creep-deforms, the sealing force of the seal member is reduced and the caulking load of the fixed portion may be reduced.

  In the present specification, in the power storage device in which the terminal is caulked and fixed to the case, a reduction in the sealing force of the sealing member disposed between the terminal and the case is suppressed even after a long period of time, and A technique for suppressing a reduction in caulking load is provided.

  The power storage device disclosed in this specification includes a case, an electrode assembly, a terminal, a current interrupt device, an O-ring, and an insulating member. The electrode assembly is accommodated in the case and includes a positive electrode and a negative electrode. The terminal protrudes from the case through an opening formed in the terminal wall of the case and communicates with the inside and outside of the case. The current interrupt device is housed in a case, and has a conductive member that is connected to the terminal and the positive electrode or the terminal and the negative electrode, and that switches the terminal and the positive electrode or the negative electrode from a conductive state to a non-conductive state. . The O-ring contacts both the terminal and the terminal wall in the projecting direction of the terminal to seal the space between the terminal and the terminal wall. The insulating member is an annular insulating member, and is disposed in the space inside the case with respect to the position of the O-ring in the space between the terminal and the terminal wall. The terminal is connected to one end of the cylindrical portion through the opening, a base portion that is located inside the case, and is connected to the other end of the cylindrical portion. A fixing portion that bends radially outward from the other end of the wire and crimps and fixes the terminal to the terminal wall. The base portion is made larger than the cylindrical portion in a state where the terminal wall is viewed in plan, and the outer edge of the base portion is connected to the outer edge of the conductive member. The O-ring is disposed in a range in which the terminal and the terminal wall face each other when the terminal wall is viewed in plan, and in a range occupied by the fixing portion, and is also in contact with the insulating member.

  In this power storage device, an O-ring is disposed in a space between the terminal and the terminal wall. An annular insulating insulating member is disposed in a space inside the case with respect to the position of the O-ring in the space between the terminal and the terminal wall. The O-ring abuts against the terminal and the terminal wall to seal the space between the terminal and the terminal wall, and abuts against the insulating member. That is, the O-ring is in contact with the terminal, the terminal wall, and the insulating member. The O-ring is sandwiched between the terminal and the terminal wall by the terminal being caulked and fixed to the terminal wall. Here, the O-ring is disposed in a range where the terminal and the terminal wall face each other when the terminal wall is viewed in plan, and in a range occupied by the fixing portion. For this reason, the direction of the caulking load is the same as the direction of the compressive force for sandwiching the O-ring, and a relatively large compressive force acts on the O-ring, and the O-ring has a gap between the terminal and the terminal wall. It can be tightly sealed. On the other hand, creep deformation occurs with time in the O-ring, but the O-ring is also in contact with an insulating member disposed between the terminal and the terminal wall. For this reason, creep deformation of the O-ring is suppressed by the insulating member, and the O-ring can maintain a good contact state with the terminal and the terminal wall. As a result, a decrease in the sealing force with which the O-ring seals between the terminal and the terminal wall is suppressed, and a decrease in the caulking load of the fixed portion is suppressed.

  Details of the technology disclosed in this specification and further improvements will be described in detail in the detailed description and examples.

1 is a longitudinal sectional view of a power storage device according to Embodiment 1. FIG. The elements on larger scale near the crimping terminal which comprises the negative electrode terminal of FIG. The elements on larger scale of the crimping terminal vicinity which comprises the positive electrode terminal of FIG. The elements on larger scale near the crimping terminal which comprises the negative electrode terminal of the electrical storage apparatus of Example 2. FIG. FIG. 9 is a partially enlarged view of the vicinity of a caulking terminal that constitutes a negative electrode terminal of a power storage device of Example 3.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Feature 1) In the power storage device disclosed in this specification, the insulating member may have creep resistance superior to that of the O-ring. According to feature 1, the insulating member is less likely to creep than the O-ring. For this reason, even if the O-ring and the insulating member undergo creep deformation, the amount of deformation of the insulating member is smaller than that of the O-ring. For this reason, the creep deformation of the O-ring can be satisfactorily suppressed by the insulating member.

(Characteristic 2) In the power storage device disclosed in this specification, an O-ring may be arranged inside the case. According to this configuration, the shape of the insulating member with which the O-ring comes into contact can be simplified, and the terminal can be easily assembled to the terminal wall.

(Characteristic 3) In addition, the present specification discloses a power storage device module including a plurality of the above power storage devices and connected to the plurality of power storage devices. In this power storage device module, each of the plurality of power storage devices constituting the power storage device module is prevented from reducing the sealing force of the seal member disposed between the terminal and the terminal wall even after a long period of time. In addition, a reduction in the caulking load of the terminal fixing portion is suppressed. For this reason, an electrical storage apparatus module can be used stably for a long period of time.

  A power storage device 100 according to a first embodiment will be described with reference to FIGS. 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 1, an electrode assembly 3, caulking terminals 5 and 7, and a current interrupt device 30. 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 30 are accommodated. The electrode assembly 3 includes a negative electrode and a positive electrode. The negative electrode current collecting tab 43 is fixed to the negative electrode, and the positive electrode current collecting tab 45 is fixed to the positive electrode. The inside of the case 1 is filled with the electrolytic solution, and the atmosphere is removed. Detailed description of the negative electrode and the positive electrode is omitted. The caulking terminals 5 and 7 correspond to an example of “terminal” in the claims.

  Openings 11 and 13 are formed in the upper wall of the case 1. Hereinafter, the upper wall of the case 1 is particularly referred to as a case upper wall 9. The caulking terminal 5 communicates with the inside and outside of the case 1 through the opening 11, and the caulking terminal 7 communicates with the inside and outside of the case 1 through the opening 13. That is, both the caulking terminal 5 and the caulking terminal 7 are arranged in the same direction with respect to the electrode assembly 3. External terminals 60 and 61 and bolts 64 and 65 for external connection are arranged outside the case 1 (described later). The caulking terminal 5, the external terminal 60, and the bolt 64 are electrically connected to each other and constitute a negative terminal. Similarly, the caulking terminal 7, the external terminal 61, and the bolt 65 are electrically connected to each other and constitute a positive terminal. The lower end of the crimping terminal 5 is located inside the case 1 and is connected to a current interrupt device 30 (described later). The current interrupt device 30 is connected to the negative current collecting tab 43 through the connection terminal 23 and the negative electrode lead 25. The negative electrode lead 25 is insulated from the case upper wall 9 by an insulating sheet 27. On the other hand, the lower end of the crimping terminal 7 is located inside the case 1 and is connected to the positive electrode current collecting tab 45 through the positive electrode lead 41. The positive electrode lead 41 is insulated from the case upper wall 9 by an insulating sheet 37. The case upper wall 9 corresponds to an example of a “terminal wall” in the claims.

  Resin gaskets 62 and 63 are arranged on the upper surface of the case upper wall 9. The gasket 62 has a protruding portion 66 protruding upward from the case upper wall 9 and a flat plate portion 68 extending along the case upper wall 9. The protruding portion 66 is disposed on the center side of the case upper wall 9, and the flat plate portion 68 is disposed on the opening 11 side of the case upper wall 9. An external terminal 60 is disposed on the upper surface of the gasket 62. The external terminal 60 has a shape that follows the shape of the upper surface of the gasket 62. The external terminal 60 is disposed along the upper surface of the gasket 62. In other words, the external terminal 60 and the upper surface of the gasket 62 have a surface contact portion. A bottomed hole 62 a is formed in the protruding portion 66 of the gasket 62. The head of the bolt 64 is disposed in the hole 62a. The shaft portion of the bolt 64 protrudes upward through the opening of the external terminal 60. The external terminal 60 and the gasket 62 are attached to the case upper wall 9 by a crimping terminal 5 (described later). Since the configuration of the gasket 63, the external terminal 61, and the bolt 65 is the same as the configuration of the gasket 62, the external terminal 60, and the bolt 64 described above, description thereof is omitted.

  Here, the caulking terminal 5 will be described with reference to FIG. FIG. 2 shows an enlarged view of the two-dot chain line portion 200a of FIG. The caulking terminal 5 has a cylindrical portion 14, a base portion 15, and a fixing portion 16. The cylindrical portion 14 has a cylindrical shape and passes through the opening 11. For this reason, the upper part of the cylindrical part 14 is located outside the case 1, and the lower part is located inside the case 1. A through hole 14a is formed in the cylindrical portion 14 in the axial direction (vertical direction in FIG. 2). For this reason, the inside of the through-hole 14a is maintained at atmospheric pressure.

  The base portion 15 has a disk shape and is connected to the lower end of the cylindrical portion 14. That is, the base portion 15 is located inside the case 1. The base portion 15 is formed in an annular shape. The upper surface of the base portion 15 is substantially orthogonal to the axial direction of the cylindrical portion 14. The outer diameter of the base portion 15 is larger than the outer diameter of the cylindrical portion 14. The cylindrical portion 14 and the base portion 15 are arranged concentrically. The outer edge of the lower surface of the base portion 15 is connected to the outer edge of a deformation plate 32 (described later) of the current interrupt device 30. A recess 15 a is formed at the center of the bottom surface of the base portion 15. The recess 15a is formed to prevent the inverted portion of the deformable plate 32 from coming into contact with the base portion 15 when the deformable plate 32 is inverted upward. Since the center of the recess 15a communicates with the through hole 14a, the interior of the recess 15a is also maintained at atmospheric pressure. In addition, the shape of the base part 15 is not restricted to a disk shape, For example, a rectangular parallelepiped shape may be sufficient. In this case, the base portion 15 only needs to be larger than the cylindrical portion 14. The same applies to the base portion 95 described later.

  The fixed portion 16 has an annular shape and is connected to the upper end of the cylindrical portion 14. That is, the fixing portion 16 is located outside the case 1. The caulking terminal 5 is fixed to the case upper wall 9 by a fixing portion 16. Before the caulking terminal 5 is fixed to the case upper wall 9, the fixing portion 16 extends in the axial direction of the cylindrical portion 14. That is, the cylindrical portion 14 and the fixed portion 16 constitute one cylindrical member extending in the axial direction. Hereinafter, in order to simplify the description, the above-described cylindrical member is referred to as a “cylindrical member”.

  When the caulking terminal 5 is fixed to the case upper wall 9, the cylindrical member is formed from the inside of the case 1 to the external terminal 60 with the gasket 62 and the external terminal 60 attached to the opening 11 of the case upper wall 9. Insert through the opening. After that, the upper end of the cylindrical member (the part protruding outside the case 1) is bent outward in the radial direction (direction orthogonal to the axial direction) to expand the cylindrical member in the radial direction. Thereby, the cylindrical member abuts on the upper surface of the external terminal 60, and the caulking terminal 5 is caulked and fixed to the case upper wall 9. The cylindrical member (that is, the bent portion of the cylindrical member) corresponds to the fixed portion 16. By fixing the caulking terminal 5 to the case upper wall 9, the O-ring 19, the gasket 62 and the external terminal 60 are sandwiched between the caulking terminal 5 and the case upper wall 9. At this time, the case upper wall 9, the base portion 15, and the fixing portion 16 are substantially parallel to each other. The O-ring 19 is in contact with the base portion 15 at the point C1, and is in contact with the case upper wall 9 at the point C2. As described above, the base portion 15 and the case upper wall 9 are substantially parallel. The cross section of the O-ring 19 is circular. For this reason, the line segment C1C2 connecting the points C1 and C2 passes through the center of the cross section of the O-ring 19. The space between the base portion 15 and the case upper wall 9 is sealed by the O-ring 19. The O-ring 19 is in contact with both the base portion 15 and the case upper wall 9 but is formed of an insulating material, so that the insulation between the base portion 15 and the case upper wall 9 is maintained. Further, the insulation between the external terminal 60 and the case upper wall 9 is ensured by the gasket 62.

  Next, with reference to FIG. 2, the positional relationship of the member arrange | positioned between the crimping terminal 5 and the case upper wall 9 is demonstrated. A space 18 surrounded by a broken line in FIG. 2 represents a space that is a region occupied by the fixing portion 16 in a region where the case upper wall 9 and the base portion 15 face each other when the case upper wall 9 is viewed in plan. That is, the space 18 is a space inside the case, and is formed so as to surround the outer periphery of the cylindrical portion 14 at a portion located inside the case. In the present embodiment, an O-ring 19 is disposed in the space 18. The O-ring 19 is disposed concentrically with the cylindrical portion 14. An ethylene-propylene rubber (EPPM) is used for the O-ring 19. The material of the O-ring 19 is not limited to this, and any material having appropriate liquid resistance against the electrolytic solution may be used. On the outer peripheral side of the O-ring 19, annular insulating support members 36 and 39 are disposed. A PPS resin is used for the support member 36. PPS resin has creep resistance superior to that of EPPM. The material of the support member 36 is not limited to this, and any material may be used as long as it has creep resistance superior to that of the O-ring 19 and also has appropriate corrosion resistance against the electrolytic solution. The creep resistance is determined by a conventionally known creep test. The amount of creep deformation increases as the load acting on the material increases and as the temperature of the material increases. Therefore, a material having suitable creep resistance is selected as the material of the O-ring 19 and the support member 36 based on the caulking load of the caulking terminal 5 and the temperature range when the power storage device 100 is used. The support member 39 is formed of the same material as that of the support member 36, but is not limited thereto, and may be formed of a material having insulation properties and electrolytic solution resistance. The O-ring 19 does not have to be disposed in the space 18 as a whole. If the center of the cross section of the O-ring 19 is located in the space 18, a part of the O-ring 19 may be located outside the space 18.

  The support members 36 and 39 are members that support the base portion 15 and the current interrupt device 30 (described later). One end surface of the support member 36 is in contact with the O-ring 19 over the circumferential direction. In FIG. 2, the support member 36 and the O-ring 19 are in contact with each other at a point C3. The cross section of the O-ring 19 is circular, and one end surface of the support member 36 is substantially orthogonal to the upper surface of the base portion 15 and the lower surface of the case upper wall 9. For this reason, the contact point C3 between the support member 36 and the O-ring 19 is located on the perpendicular bisector of the line segment C1C2. The support member 36 covers the upper surface and the outer peripheral surface of the base portion 15. The other end surface of the support member 36 is in contact with one end surface of the support member 39. The other end of the support member 39 covers the outer edge of the lowermost member (breaking plate 34 (described later)) of the current interrupt device 30 in the circumferential direction. An annular metal plate 40 is disposed on the outer peripheral side of the support members 36 and 39. Specifically, after the support members 36 and 39 are arranged at predetermined positions, the upper and lower ends of the plate member 40 are caulked to the outer peripheral surfaces of the support members 36 and 39. According to this configuration, the support member 36 is necessarily arranged in a space on the outer peripheral side of the O-ring 19 and in a range where the base portion 15 and the case upper wall 9 face each other. In other words, the support member 36 is always disposed in the space between the base portion 15 and the case upper wall 9 in the case inner side than the position of the O-ring 19. The support member 36 corresponds to an example of “insulating member” in the claims.

  A downwardly extending portion 68 a is formed on the outer periphery of the opening formed in the flat plate portion 68 of the gasket 62. The portion 68 a is fitted into the opening 11. By the portion 68a, the caulking terminal 5 and the case upper wall 9 are more reliably insulated from each other, and the gasket 62 can be easily positioned. A space is formed between the O-ring 19 and the portion 68a.

  Subsequently, the positional relationship between the crimping terminal 7 and the crimping terminal 7 and the case upper wall 9 will be described with reference to FIG. 3. FIG. 3 shows an enlarged view of the two-dot chain line portion 200b of FIG. A description of the same configuration as that of the caulking terminal 5 will be omitted, and different points will be described. The caulking terminal 7 has a cylindrical portion 94, a base portion 95, and a fixing portion 96. The caulking terminal 7 is solid, and no through hole and recess are formed. The caulking terminal 7 is caulked and fixed to the case upper wall 9 by bending the fixing portion 96 radially outward as shown in FIG. As a result, the O-ring 99, the gasket 63 and the external terminal 65 are sandwiched between the caulking terminal 7 and the case upper wall 9. At this time, the case upper wall 9, the base portion 95, and the fixing portion 96 are parallel to each other. The O-ring 99 is in contact with the base portion 95 at the point C4, and is in contact with the case upper wall 9 at the point C5. The base portion 95 is connected to the positive electrode lead 41. The caulking terminal 7 is not limited to a solid member, and a through hole may be formed in the cylindrical portion 94.

  A space 98 surrounded by a broken line in FIG. 3 represents a space in a range occupied by the fixed portion 96 in a range where the case upper wall 9 and the base portion 95 face each other when the case upper wall 9 is viewed in plan. An O-ring 99 is disposed in the space 98. An annular insulating member 116 is disposed on the outer peripheral side of the O-ring 99. The insulating member 116 is made of a material having creep resistance superior to that of the O-ring 99 (for example, a PPS resin similar to the support member 36). The inner peripheral surface of the insulating member 116 is in contact with the O-ring 99 in the circumferential direction (in FIG. 3, it is in contact with the point C6). The outer peripheral surface of the insulating member 116 extends to the position of the outer surface of the base portion 95. According to this configuration, the insulating member 116 is necessarily arranged in a space on the outer peripheral side of the O-ring 99 and in a range where the base portion 95 and the case upper wall 9 face each other.

  In a power storage device module including a plurality of power storage devices 100, each power storage device 100 is connected in series and connected in series until a desired voltage is obtained. Thereby, a high-output and large-capacity power storage device module can be configured.

  Returning to FIG. 2, the current interrupt device 30 will be described. The current interrupt device 30 includes a metal deformation plate 32 and a metal break plate 34. The current interrupt device 30 is located below the crimping terminal 5 and is not located below the bolt 64. The outer edge of the deformable plate 32 is connected to the outer edge of the base portion 15, and the lower end of the recess 15 a of the base portion 15 is covered with the deformable plate 32. The deformable plate 32, the fracture plate 34 and the base portion 15 are supported by annular insulating support members 36 and 39. A metal plate 40 is caulked on the outer peripheral surfaces of the support members 36 and 39. Thereby, the base part 15, the deformation | transformation board 32, and the fracture | rupture board 34 are clamped to an up-down direction. The deformation plate 32 is a conductive diaphragm having a circular shape when seen in a plan view, and protrudes downward. As described above, the outer edge of the deformable plate 32 is connected to the outer edge of the base portion 15, and the central portion of the deformable plate 32 is connected to the fracture plate 34. The fracture plate 34 is a circular plate material and is located below the deformation plate 32. The connection terminal 23 is connected to a part of the outer edge of the fracture plate 34. A groove 34 a is formed at the center of the lower surface of the fracture plate 34. The groove 34a is formed to be circular when the fracture plate 34 is viewed from the bottom. The fracture plate 34 and the center portion of the deformation plate 32 are connected inside the groove 34a. By forming the groove 34a, the mechanical strength of the fracture plate 34 at the position where the groove 34a is formed is lower than the mechanical strength of the fracture plate 34 at a position other than the groove 34a. A vent hole 34 b is formed in a part of the breaking plate 34, and a space between the deformation plate 32 and the breaking plate 34 communicates with a space in the case 1. An annular insulating member 38 is disposed between the outer edge of the deformable plate 32 and the outer edge of the fracture plate 34. The deformable plate 32 corresponds to an example of “conductive member” in the claims.

  The current interrupt device 30 has an energization path that connects the connection terminal 23, the fracture plate 34, the deformation plate 32, and the crimping terminal 5 in series. For this reason, the electrode assembly 3 and the caulking terminal 5 are electrically connected via the energization path of the current interrupt device 30.

  Here, the interruption operation of the current interruption device 30 will be described. In the power storage device 100 described above, the caulking terminal 5 and the negative electrode current collecting tab 43 (negative electrode) are electrically connected, and the caulking terminal 7 and the positive electrode current collecting tab 45 (positive electrode) are electrically connected. Therefore, the caulking terminal 5 and the caulking terminal 7 can be energized. When the pressure in the case 1 increases, the pressure acting on the lower surface of the deformation plate 32 increases. However, the deformation plate 32 does not reverse until the pressure in the case 1 exceeds a predetermined value. When the pressure in the case 1 exceeds a predetermined value, the deformation plate 32 receives and reverses the pressure in the case 1 and changes from a downwardly convex state to an upwardly convex state. Then, according to the change of the deformation plate 32, the break plate 34 connected to the central portion of the deformation plate 32 breaks starting from the mechanically fragile groove 34a. And the fracture | rupture board 34 isolate | separates into the part enclosed by the groove part 34a, and the outer peripheral part of the groove part 34a. As a result, the energization path connecting the fracture plate 34 and the deformation plate 32 is interrupted, and the energization between the electrode assembly 3 and the crimping terminal 5 is interrupted.

  The effect of the electrical storage apparatus 100 of Example 1 is demonstrated. In the power storage device 100, the O-ring 19 is in contact with the base portion 15 at the point C1, and is in contact with the case upper wall 9 at the point C2. Further, a support member 36 (insulating member 116 in the case of the crimping terminal 7) is disposed on the inner side of the case from the position of the O-ring 19, and the O-ring 19 is in contact with the support member 36 at a point C3. That is, the ring 19 is in contact with the base portion 15, the case upper wall 9, and the support member 36 at three points. The straight line C1C2 is a straight line passing through the center of the cross section of the O-ring 19, and the point C3 is a point on the perpendicular bisector of the line segment C1C2. When the caulking terminal 5 (strictly, the fixing portion 16) is caulked and fixed to the case upper wall 9, a caulking load acts on the O-ring 19 in the direction of the straight line C2C1 by the fixing portion 16. For this reason, the O-ring 19 tends to creep and deform with time. Specifically, the O-ring 19 is compressed and deformed in the direction of the straight line C2C1, and tries to be deformed so as to spread in a direction orthogonal to the straight line C2C1 (hereinafter referred to as an orthogonal direction).

  However, in this embodiment, since the O-ring 19 is in contact with the support member 36 at the point C3, the support member 36 prevents the O-ring 19 from being deformed so as to spread in the orthogonal direction. For this reason, the O-ring 19 is suppressed from being deformed in the direction of the straight line C2C1. Accordingly, the O-ring 19 can maintain a good contact state with the base portion 15 and the case upper wall 9 at the points C1 and C2. As a result, even if the caulking terminal 5 is caulked and fixed to the case upper wall 9 for a long time, the sealing force by which the O-ring 19 seals the space between the base portion 15 and the case upper wall 9 is reduced. This is suppressed, and the caulking load of the fixing portion 16 is suppressed from decreasing.

  In the present embodiment, the O-ring 19 is disposed in the space 18. That is, when the case upper wall 9 is seen in a plan view, the O-ring 19 overlaps the fixing portion 16. For this reason, a relatively large caulking load acts on the O-ring 19. As a result, the sealing force of the O-ring 19 is improved as compared with the configuration in which the O-ring 19 is disposed outside the space 18. That is, according to the configuration of the present embodiment, the O-ring 19 can maintain a relatively high sealing force over a long period of time, and the performance of the power storage device 100 is improved.

  In this embodiment, two different members, that is, an O-ring 19 and a support member 36 are disposed between the base portion 15 and the case upper wall 9. According to this configuration, the deformation of the O-ring 19 is restrained by the support member 36. For this reason, it is possible to further suppress the deformation of the O-ring 19 as compared with the configuration in which there is one seal member disposed between the base portion 15 and the case upper wall 9.

  Further, according to the configuration of the power storage device 100, the support member 36 is always disposed in a space on the outer peripheral side of the O-ring 19 and in a range where the base portion 15 and the case upper wall 9 face each other. For this reason, in the said space, the base part 15 and the case upper wall 9 do not directly oppose. Therefore, even if the electrolytic solution enters the space between the support member 36 and the case upper wall 9, the base portion 15 and the case upper wall 9 do not conduct through the electrolytic solution. As a result, insulation between the base portion 15 and the case upper wall 9 can be ensured. Further, since the O-ring 19 seals between the base portion 15 and the case upper wall 9, the electrolytic solution is prevented from flowing out of the case from the position of the O-ring 19. In addition, since the O-ring 99 which contacts each of the base portion 95 of the crimping terminal 7, the case upper wall 9, and the insulating member 116 at three points also has the same effect as described above, the description thereof is omitted. As for the following functions and effects, unless otherwise specified, the O-ring 99 and the insulating member 116 have the same functions and effects as those of the O-ring 19 and the support member 36, and a description thereof will be omitted. The same applies to the other embodiments.

  When a caulking load acts on the O-ring 19, a part of the caulking load acts on the support member 36 at the point C3. In the present embodiment, the support member 36 is made of a material that is more excellent in creep resistance than the O-ring 19. That is, the support member 36 is less likely to creep than the O-ring 19. For this reason, even if a part of the caulking load is applied to the support member 36, the support member 36 is suppressed from being deformed, and the support member 36 can maintain a good contact state with the O-ring 19. Therefore, deformation of the O-ring 19 can be suppressed, and a decrease in the sealing force of the O-ring 19 can be further suppressed.

  In this embodiment, the O-ring 19 is disposed inside the case 1. For this reason, the shape of the support member 36 can be simplified, and the manufacturing efficiency of the power storage device 100 can be improved.

  Next, Example 2 will be described with reference to FIG. Hereinafter, only differences from the first embodiment will be described, and detailed description of the same configurations as those of the first embodiment will be omitted. The same applies to other embodiments.

  A two-dot chain line portion 300a in FIG. 4 corresponds to the two-dot chain line portion 200a in FIG. 1 and shows a partially enlarged view in the vicinity of the crimping terminal 5 of the second embodiment. A space 118 surrounded by a broken line in FIG. 4 represents a space that is an area where the case upper wall 9 and the fixing portion 16 face each other when the case upper wall 9 is viewed in plan, and is a space outside the case. In the present embodiment, an O-ring 119 is disposed in the space 118. The O-ring 119 is in contact with the fixed portion 16 at the point C7, and is in contact with the case upper wall 9 at the point C8. The O-ring 119 seals between the fixed portion 16 and the case upper wall 9 and insulates the fixed portion 16 from the case upper wall 9.

  An annular insulating member 136 and an annular insulating support member 137 are arranged in a space inside the case with respect to the position of the O-ring 119 in the space between the crimping terminal 5 and the case upper wall 9. . One end surface of the insulating member 136 is in contact with the O-ring 119 at a point C 9, and the other end surface of the insulating member 136 is in contact with one end surface of the support member 137. The insulating member 136 covers the outer periphery of the cylindrical portion 14. The support member 137 covers the outer periphery of the cylindrical portion 14 and is disposed between the base portion 15 and the case upper wall 9. The cylindrical portion 14 and the base portion 15 are insulated from the case upper wall 9 by the insulating member 136 and the support member 137. The base 15 and the current interrupt device 30 are supported by support members 137 and 139. A metal plate 140 is caulked on the outer peripheral surfaces of the support members 137 and 139. In the power storage device of this embodiment, the insulating member 136 and the support member 137 are formed as separate members.

  Also with this configuration, the deformation of the O-ring 119 is restrained by the insulating member 136. For this reason, it is suppressed that the sealing force in which the O-ring 119 seals the space between the fixing portion 16 and the case upper wall 9 is reduced, and the caulking load of the fixing portion 16 is suppressed from being reduced. Further, since the O-ring 119 is disposed in a range where the fixing portion 16 and the case upper wall 9 face each other when the case upper wall 9 is viewed in plan, a relatively large caulking load acts on the O-ring 119. Therefore, the O-ring 119 can maintain a relatively high sealing force over a long period of time, and the performance of the power storage device is improved. Further, by arranging the O-ring 119 and the insulating member 136 as separate members, deformation of the O-ring 119 can be further suppressed. In addition, the caulking terminal 5 and the case upper wall 9 are prevented from conducting by the electrolytic solution.

  A two-dot chain line portion 400a in FIG. 5 corresponds to the two-dot chain line portion 200a in FIG. 1 and shows a partially enlarged view in the vicinity of the crimping terminal 5 of the third embodiment. In this power storage device, the configuration of the current interrupt device is different from that of the first embodiment. The current interrupt device 70 includes a metal first deformation plate 71, a metal break plate 73, and a metal second deformation plate 75. The first deformation plate 71, the fracture plate 73, the second deformation plate 75, and the base portion 15 of the crimping terminal 5 are supported by insulating support members 77 and 78. A metal plate 79 is caulked on the outer peripheral surfaces of the support members 77 and 78. Thereby, the base part 15, the 1st deformation board 71, the fracture | rupture board 73, and the 2nd deformation board 75 are clamped to an up-down direction. With this configuration, the current interrupt device 70 is attached to the crimping terminal 5.

  The first deformation plate 71 is a circular plate material and is disposed below the fracture plate 73. The lower surface of the outer edge of the first deformation plate 71 is supported by the support member 78 over the entire circumference. An insulating member 81 is disposed on the upper surface of the outer edge of the first deformation plate 71. The insulating member 81 is an annular member, and insulates the first deformation plate 71 and the fracture plate 73. In addition, a protrusion 83 is provided on the upper surface of the first deformation plate 71. The protrusion 83 is located at the center of the first deformation plate 71. The protruding portion 83 protrudes upward toward the fracture plate 73. Above the protrusion 83, the central portion 73b of the fracture plate 73 is located. When the fracture plate 73 and the protruding portion 83 are viewed from the bottom, the outer periphery of the protruding portion 83 is smaller than the outer periphery of the central portion 73b. Note that the pressure in the space in the case 1 acts on the lower surface of the first deformation plate 71. The pressure of the space 86 between the first deformation plate 71 and the fracture plate 73 acts on the upper surface of the first deformation plate 71. The space 86 is sealed from the space in the case 1. Therefore, when the pressure in the space in the case 1 is increased, the pressure acting on the upper surface and the lower surface of the first deformation plate 71 is different.

  The fracture plate 73 is a circular plate material and is disposed between the first deformation plate 71 and the second deformation plate 75. The connection terminal 23 is connected to a part of the outer peripheral portion of the fracture plate 73. A groove 73 a is formed at the center of the lower surface of the fracture plate 73. The groove 73a is formed in a circular shape when viewed from the bottom. The cross-sectional shape of the groove 73a is a triangular shape that protrudes upward. By forming the groove 73a, the mechanical strength of the fracture plate 73 at the position where the groove 73a is formed is lower than the mechanical strength of the fracture plate 73 at a position other than the groove 73a. The fracture plate 73 is divided into a central part 73b surrounded by the groove part 73a and an outer peripheral part 73c located on the outer peripheral side of the groove part 73a by the groove part 73a. The central portion 73b is thin, and the outer peripheral portion 73c is thick.

  The second deformation plate 75 is a circular plate material and is disposed above the fracture plate 73. The central portion of the second deformable plate 75 is convex downward and is fixed to the central portion 73 b of the fracture plate 73. The outer peripheral portion of the second deformation plate 75 is electrically connected to the base portion 15 of the crimping terminal 5. An insulating member 85 is disposed between the second deformable plate 75 and the fracture plate 73. The insulating member 85 is an annular member, and is in contact with the outer peripheral portion of the second deformation plate 75 and the outer peripheral portion of the fracture plate 73. A space 87 is formed between the upper surface of the second deformation plate 75 and the lower surface of the base portion 15. A seal member 89 is disposed between the fracture plate 73 and the outer peripheral portion of the base portion 15. The seal member 89 is an annular member and is disposed outside the insulating member 85. The seal member 89 is in contact with the lower surface of the base portion 15 and the upper surface of the fracture plate 73, and makes a round along the outer peripheral portions of the base portion 15 and the fracture plate 73. The seal member 89 seals the gap between the base portion 15 and the fracture plate 73. The space 87 communicates with a through hole 14 a provided in the crimping terminal 5. The second deformable plate 75 corresponds to an example of “conductive member” in the claims.

  The energization path of the current interrupt device 70 will be described. The fracture plate 73 is connected to the second deformation plate 75 at the central portion 73b. The outer peripheral portion of the second deformation plate 75 is connected to the crimping terminal 5. Therefore, the current interrupt device 70 has an energization path that connects the connection terminal 23, the fracture plate 73, the second deformation plate 75, and the crimping terminal 5 in series. For this reason, the electrode assembly 3 and the caulking terminal 5 are electrically connected via the energization path of the current interrupt device 70.

  Here, the interruption operation of the current interruption device 70 will be described. In the power storage device described above, the caulking terminal 5 and the negative electrode current collecting tab 43 (negative electrode) are electrically connected, and the caulking terminal 7 and the positive electrode current collecting tab 45 (positive electrode) are electrically connected. For this reason, between the caulking terminal 5 and the caulking terminal 7 can be energized. When the pressure in the case 1 increases, the pressure acting on the lower surface of the first deformation plate 71 increases. However, the first deformation plate 71 does not reverse until the pressure in the case 1 exceeds a predetermined value. The pressure acting on the upper surface of the first deformation plate 71 (pressure from the space 86) is not affected by the pressure increase in the case 1 and does not change. For this reason, when the pressure in the case 1 exceeds a predetermined value, the first deformation plate 71 is reversed and changes from a downwardly convex state to an upwardly convex state. When the first deforming plate 71 is reversed, the protruding portion 83 of the first deforming plate 71 collides with the central portion 73b of the breaking plate 73, and the breaking plate 73 is broken at the groove 73a. Then, according to the displacement of the first deformation plate 71, the second deformation plate 75 is also reversed, and the second deformation plate 75, the central portion of the fracture plate 73, and the first deformation plate 71 are displaced upward. As a result, the energization path connecting the fracture plate 73 and the second deformation plate 75 is interrupted, and the electrical connection between the electrode assembly 3 and the crimping terminal 5 is interrupted. The above-described current interrupt device 70 may be attached to the power storage device of the second embodiment. Also according to the configuration of the power storage device of the third embodiment, the same operational effects as those of the first embodiment can be obtained.

  As described above, the embodiments of the technology disclosed in this specification have been described in detail. However, these are merely examples, and the power storage device disclosed in this specification includes various modifications and changes of the above-described embodiments. It is. For example, in the first embodiment, the support member 36 that contacts the O-ring 19 has a role of supporting the base portion 15 and the current interrupt device 30 together with the support member 39, but is not limited to this configuration. That is, the member that contacts the O-ring 19 and the member that supports the base portion 15 and the current interrupt device 30 may be formed separately. In the first embodiment, a space is formed between the O-ring 19 and the portion 68a. However, the present invention is not limited to this. For example, an insulating member may be disposed in the space, or the portion 68a and the O-ring 19 may be in contact with each other. When the insulating member or portion 68a and the O-ring 19 are in contact with each other, creep deformation of the O-ring 19 is further suppressed. Further, the current interrupt device 30 and the current interrupt device 70 may be provided on the caulking terminal 7 side, or may be provided on both the caulking terminal 5 and the caulking terminal 7. Further, the O-ring may be creep-deformed to such an extent that the O-ring can be kept in contact with the crimping terminal and the upper wall of the case during the period when the service life of the O-ring elapses. According to this configuration, the O-ring can appropriately seal between the crimping terminal and the case upper wall during the period when the service life of the O-ring elapses. Further, in the above-described embodiment, the deformation plate 32 is reversed, and the conduction with the fracture plate 34 is interrupted. However, the deformation method of the deformation plate 32 is not limited to inversion. For example, a configuration in which the central portion of the deformable plate 32 bends upward causes the breakable plate 34 to break from the groove 34a and the conduction between the deformable plate 32 and the breakable plate 34 is interrupted. The deformation plate 32 may be deformed in any way as long as the conduction between the deformation plate 32 and the fracture plate 34 is interrupted. The same applies to the second deformation plate 75.

  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. 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 illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

1: Case, 3: Electrode assembly, 5: Caulking terminal, 7: Caulking terminal, 9: Case upper wall, 11: Opening, 13: Opening, 14: Cylindrical part, 15: Base part, 16: Fixing part, 19 : O-ring, 30: Current interrupt device, 32: Deformation plate, 36: Support member, 100: Power storage device

Claims (4)

Case and
An electrode assembly housed in the case and comprising a positive electrode and a negative electrode;
A terminal projecting from the case through an opening formed in the terminal wall of the case and communicating with the inside and outside of the case;
Conductivity contained in the case, connected to the terminal and the positive electrode or the terminal and the negative electrode, and switching the terminal and the positive electrode or the negative electrode from a conductive state to a non-conductive state A current interrupting device having a member;
An O-ring that abuts both the terminal and the terminal wall in the projecting direction of the terminal and seals a space between the terminal and the terminal wall;
An annular insulating insulating member disposed in the space inside the case with respect to the position of the O-ring in the space between the terminal and the terminal wall; and
The terminal is connected to the cylindrical portion that penetrates the opening, a base portion that is connected to one end of the cylindrical portion and located inside the case, and is connected to the other end of the cylindrical portion. And a fixing portion that bends radially outward from the other end of the cylindrical portion and fixes the terminal to the terminal wall by caulking,
The base portion is larger than the cylindrical portion in a state where the terminal wall is seen in plan view, and an outer edge of the base portion is connected to an outer edge of the conductive member,
The O-ring is disposed in a range in which the terminal and the terminal wall face each other when the terminal wall is viewed in plan and in a range occupied by the fixing portion, and is in contact with the insulating member. A power storage device.   The power storage device according to claim 1, wherein the insulating member has creep resistance superior to that of the O-ring.   The power storage device according to claim 1, wherein the O-ring is disposed inside the case.   A power storage device module comprising a plurality of power storage devices according to claim 1, wherein the plurality of power storage devices are connected.

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