JP6314692B2 - Current interrupt device and power storage device using the same - Google Patents

Description

  The present specification discloses a technology related to a current interrupt device and a power storage device using the current interrupt device.

  Development of a current interrupting device that interrupts a current flowing between electrode terminals (a positive electrode terminal and a negative electrode terminal) when a power storage device is overcharged or a short circuit occurs inside is underway. The current interrupting device is disposed between the electrode terminal and the electrode (between the positive electrode terminal and the positive electrode or between the negative electrode terminal and the negative electrode). The current interrupting device of Patent Document 1 includes a first energization member connected to the electrode terminal and a second energization member connected to the electrode. The 2nd electricity supply member is arrange | positioned in the position facing a 1st electricity supply member. A deformation member is disposed between the first energization member and the second energization member. The peripheral edge of the deformable member is fixed to the first energizing member. In patent document 1, when the pressure in a case is below a predetermined value, the center part of a deformation member is contacting the 2nd electricity supply member, and the electrode terminal and the electrode are electrically connected. When the pressure in the case exceeds a predetermined value, the central portion of the deformable member is not in contact with the second energizing member, and conduction between the electrode terminal and the electrode is interrupted.

International Publication WO2013 / 154166A1

  In the current interrupting device of Patent Document 1, when the pressure in the case exceeds a predetermined value, the central portion of the deformable member moves to the first energizing member side, thereby interrupting conduction between the electrode terminal and the electrode. Specifically, the second energization plate is broken, the pressure in the case is applied to the deformable member, and the central portion of the deformable member changes from a state projecting toward the second energizing member side to a state projecting toward the first energizing member side. Invert. In Patent Literature 1, the entire circumference of the peripheral edge of the deformable member is fixed to the first energizing member. Therefore, the deformation member may be applied with a force that suppresses the deformation member from being reversed to the first energization member side. Alternatively, a force is applied from the deformable member to the second energizing plate, the second energizing member resists the pressure increase in the case, and the second energizing plate is not easily broken even if the pressure in the case exceeds a predetermined value. Sometimes. As a result, the responsiveness of the current interrupt device to the pressure increase in the case may be reduced. Therefore, conventionally, the deformation member is adjusted to be deformed at a pressure lower than the pressure in the case reaching the pressure at which the current should be cut off. In this specification, the technique which implement | achieves the electric current interruption apparatus excellent in the responsiveness with respect to the pressure change in a case is provided.

  The current interrupting device disclosed in the present specification interrupts conduction between the electrode terminal and the electrode when the pressure in the case of the power storage device exceeds a predetermined value. The current interrupt device includes a first energization member, a second energization member, and a deformation member. The first energization member is connected to the electrode terminal. The second energization member is connected to the electrode. The deformable member is disposed between the first energizing member and the second energizing member. The deformation member is connected to the first energization member. The deformable member is in contact with the second energizing member when the pressure in the case is equal to or lower than a predetermined value, and the second energizing member when the pressure in the case exceeds a predetermined value. Contactless. In the current interrupt device disclosed in the present specification, a part of the periphery of the deformable member is connected to the first energizing member, and another part of the periphery of the deformable member is connected to the first energizing member. Not connected.

  The “periphery of the deformable member” is not limited to the outer edge of the deformable member, but is a position that surrounds the central portion of the deformable member and is a region having a range that can be connected to the first energizing member. Means that. For example, when the deformable member is a rectangle, the region outside the line connecting the midpoints of the distance between the center of the rectangle and the outer edge of the rectangle is the “periphery of the deformable member”. When the deforming member is a circle, the region that is concentric with the deforming member and outside the half of the deformation of the deforming member is the “periphery of the deforming member”.

  In said electric current interruption apparatus, the periphery of a deformation | transformation member is equipped with the area | region which is not connected with the 1st electricity supply member. Therefore, when the pressure in the case is applied to the deformable member, it is difficult to apply a force to the deformable member to prevent the deformable member from separating from the second energizing member. Further, it is difficult for the deformable member to apply a force against the pressure increase in the case to the second energizing member. As a result, the deformable member is easily separated from the second energizing member when the pressure in the case exceeds a predetermined value. The current interrupting device described above has better responsiveness to pressure changes in the case than the conventional current interrupting device.

  According to the technology disclosed in this specification, it is possible to realize a current interrupting device that is excellent in responsiveness to a pressure change in the case.

Sectional drawing of the electrical storage apparatus of 1st Example is shown. The expanded sectional view of the electric current interruption apparatus used with the electrical storage apparatus of 1st Example is shown. The figure explaining the connection state of a 1st electricity supply member and a deformation | transformation member is shown. The figure explaining the characteristic of the electrical storage apparatus of 2nd Example is shown. The figure explaining the characteristic of the electrical storage apparatus of 3rd Example is shown. The figure explaining the characteristic of the electrical storage apparatus of 4th Example is shown. The figure explaining the characteristic of the electrical storage apparatus of 5th Example is shown. Sectional drawing of the electrical storage apparatus of 6th Example is shown. The expanded sectional view of the electric current interruption apparatus used with the electrical storage apparatus of 6th Example is shown. Sectional drawing of the electrical storage apparatus of 7th Example is shown. The expanded sectional view of the electric current interruption apparatus used with the electrical storage apparatus of 7th Example is shown.

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

  The power storage device includes a case, an electrode assembly, an electrode terminal, and a current interrupt device. The electrode assembly is housed in a case and may include a positive electrode and a negative electrode. The electrode terminal may pass through the inside and outside of the case. That is, a part of the electrode terminal may be located outside the case, and the other part of the electrode terminal may be located inside the case. The current interrupt device may be connected to the negative terminal and the negative electrode. In this case, the current interrupt device is disposed on the energization path between the negative electrode terminal and the negative electrode, and switches the negative electrode terminal and the negative electrode from the conductive state to the non-conductive state when the internal pressure of the case exceeds a predetermined value. The current interruption device may be connected to the positive electrode terminal and the positive electrode. In this case, the current interrupt device is disposed on the energization path between the positive electrode terminal and the positive electrode, and switches the positive electrode terminal and the positive electrode from the conductive state to the non-conductive state when the internal pressure of the case exceeds a predetermined value.

  The current interrupt device may include a first energization member, a second energization member, and a deformation member. The first energization member may be fixed to the case of the power storage device. The first energizing member may be a part of the positive electrode terminal or a part of the negative electrode terminal. Alternatively, the first energizing member may be a conductive component connected to the electrode terminal (positive electrode terminal or negative electrode terminal). The shape of the end surface on the second energizing member side of the first energizing member may be a rectangle or a circle.

  The 2nd electricity supply member may be connected to the electrode. Further, the second energization member may be disposed at a position facing the first energization member at an interval from the first energization member. The thickness of the center part of the second energizing member may be thinner than the thickness of the end part. A rupture groove may be provided in the central portion of the second energization member that serves as a rupture starting point when the pressure in the case exceeds a predetermined value. The breaking groove may be continuously or intermittently made in the center of the second energizing member. In addition, the fracture | rupture groove | channel should just be a weak part used as the starting point of a fracture | rupture when the pressure in a case exceeds predetermined value, and may be provided locally in the center part of the 2nd electricity supply member.

  The deformable member may be disposed between the first energizing member and the second energizing member. That is, the deformation member may be connected to the first energizing member and the second energizing member. A part of the periphery of the deformable member may be connected to the first energizing member. Further, a part of the periphery of the deformable member is connected to the first energizing member, and the other part of the periphery of the deformable member may not be connected to the first energizing member. A part of the periphery of the deformable member may be connected to the first energizing member, and the central portion of the deformable member may be connected to the second energizing member. Alternatively, a part of the periphery of the deformable member may be connected to the first energizing member, and a part of the other periphery of the deformable member may be connected to the second energizing member. The deformable member may be in contact with the central portion of the second energizing member when the pressure in the case is equal to or lower than a predetermined value. The deformable member may be fixed to the second energizing member at a position surrounded by the fracture groove. The deformable member may be out of contact with the second energizing member when the pressure in the case exceeds a predetermined value. When the pressure in the case exceeds a predetermined value, the central portion of the second energizing member may be broken, and the deformable member may be out of contact with the second energizing member.

  The length of the region where the periphery of the deformation member is connected to the first current-carrying member in the direction of going around the outer edge of the deformation member may be less than or equal to half the length of the entire periphery of the periphery of the deformation member. When the shape of the first energizing member on the second energizing member side is a rectangle, the deformable member may be connected to one side of the rectangular end surface of the first energizing member. In the case where the first current-carrying member is a component connected to the electrode terminal, the position where the deformable member is connected to the first current-carrying member when the current interrupting device is viewed in plan is relative to the center of the second current-carrying member. The first current-carrying member may be on the side connected to the electrode terminal. The deformable member may be a polygon. Further, only one of the sides defining the deformable member may be connected to the first energizing member.

  The current interrupting device may include a second deforming member in addition to the above-described deforming member. The 2nd deformation board may be arranged on the opposite side to the above-mentioned deformation member to the 2nd energization member. That is, the 2nd electricity supply member may be provided between the 1st deformation member and the 2nd deformation member. Hereinafter, the deformable member disposed between the first energizing member and the second energizing member may be referred to as a first deformable member, and the second deformable member may be referred to as a second deformable member. The second deformation member may be provided between the second energization member and the electrode assembly. The second deformable member may be fixed to the second energizing member. The second deforming member protrudes in a direction away from the second energizing member when the pressure in the case is equal to or lower than a predetermined value, and the central portion is second energized when the pressure in the case exceeds the predetermined value. You may move toward the member. The second deformation member may be made of metal.

  The second deformation member may separate the inside and the outside of the current interrupt device. That is, the second deformable member may constitute the outer surface of the current interrupt device, and the pressure in the case may act directly on the second deformable member. A protrusion having a shape protruding toward the second energization member may be provided at the center of the second deformable member on the second energization member side. The protrusion may face a portion surrounded by the fracture groove of the second energizing member in a state of being separated from the second energizing member. The protrusion may be insulative. A 2nd electricity supply member may be fractured | ruptured when protrusion (2nd deformation member) contacts a 2nd electricity supply member.

  As examples of the power storage device disclosed in this specification, a secondary battery, a capacitor, and the like can be given. As an example of an electrode assembly of a secondary battery, a stacked electrode assembly in which a plurality of cells having electrode pairs (a negative electrode and a positive electrode) opposed via a separator are stacked, and a sheet having an electrode pair opposed via a separator And a wound electrode assembly in which the cells are spirally processed. Further, the power storage device disclosed in this specification is mounted on, for example, a vehicle and can supply electric power to a motor. Hereinafter, the structure of the power storage device will be described. In the following description, a power storage device in which a current interrupting device is connected to a negative electrode terminal and a negative electrode will be described. The technology disclosed in this specification can also be applied to a power storage device in which a current interrupting device is connected to a positive electrode terminal and a positive electrode.

(First embodiment)
The structure of the power storage device 100 will be described with reference to FIG. The power storage device 100 includes a case 18, an electrode assembly 52, a positive electrode terminal 2, a negative electrode terminal 30, and a current interrupt device 50. The case 18 is made of metal and has a substantially rectangular parallelepiped shape. The case 18 includes a lid portion 18a and a main body portion 18b. An electrode assembly 52 and a current interrupt device 50 are accommodated in the case 18. The electrode assembly 52 includes a positive electrode and a negative electrode (not shown). The positive electrode tab 16 is fixed to the positive electrode, and the negative electrode tab 20 is fixed to the negative electrode. An electrolyte is injected into the case 18.

  The positive electrode terminal 2 and the negative electrode terminal 30 pass through the inside and outside of the case 18. The positive electrode terminal 2 and the negative electrode terminal 30 are arranged in one direction of the case 18. That is, both the positive electrode terminal 2 and the negative electrode terminal 30 are disposed in the same direction (side on which the lid portion 18 a is provided) with respect to the electrode assembly 52. The positive electrode terminal 2 includes a bolt portion 8. The bolt portion 8 is a portion of the positive electrode terminal 2 that is threaded to fasten the nut 10. The positive terminal 2 is fixed to the case 18 by engaging the nut 10 with the bolt portion 8. One end of the positive electrode terminal 2 is located outside the case 18, and the other end is located inside the case 18. Similarly, the negative electrode terminal 30 includes a bolt portion 36. The bolt portion 36 is a portion of the negative electrode terminal 30 that is threaded to fasten the nut 38. The negative terminal 30 is fixed to the case 18 by engaging a nut 38 with the bolt portion 36. One end of the negative electrode terminal 30 is located outside the case 18, and the other end is located inside the case 18.

  A positive electrode lead 14 is connected to the positive electrode terminal 2. The positive lead 14 is connected to the positive tab 16. The positive electrode terminal 2 is electrically connected to the positive electrode tab 16 via the positive electrode lead 14. That is, the positive terminal 2 is electrically connected to the positive electrode of the electrode assembly 52. The positive electrode lead 14 is insulated from the case 18 by the insulating sheet 12. The positive electrode terminal 2 and the nut 10 are insulated from the case 18 by an insulating member 58. In the case 18, an insulating seal member 56 is disposed between the positive electrode terminal 2 and the case 18. A gap between the positive electrode terminal 2 and the case 18 is sealed by a seal member 56. The seal member 56 is an insulating O-ring. The bus bar 4 is fixed to the positive electrode terminal 2 by bus bar bolts 6.

  The current interrupt device 50 is connected to the negative terminal 30. The current interrupt device 50 is connected to the negative electrode lead 24 through a metal connection member 26. Details of the current interrupt device 50 will be described later. The negative electrode terminal 30 is electrically connected to the negative electrode tab 20 via the negative electrode lead 24. That is, the negative electrode terminal 30 is electrically connected to the negative electrode of the electrode assembly 52. The negative electrode lead 24 is insulated from the case 18 by the insulating sheet 22. The negative terminal 30 and the nut 38 are insulated from the case 18 by the insulating member 28. In the case 18, an insulating seal member 42 is disposed between the negative electrode terminal 30 and the case 18. A gap between the negative electrode terminal 30 and the case 18 is sealed by a seal member 42. The seal member 42 is an insulating O-ring. The bus bar 32 is fixed to the negative electrode terminal 30 by the bus bar bolt 34.

  In the power storage device 100, the negative electrode terminal 30 and the negative electrode tab 20 are electrically connected via the current interrupt device 50 when the pressure in the case 18 is equal to or lower than a predetermined value. That is, the negative electrode terminal 30 and the negative electrode are electrically connected. When the pressure in the case 18 exceeds a predetermined value, the current interrupt device 50 interrupts conduction between the negative electrode terminal 30 and the negative electrode tab 20, and prevents current from flowing through the power storage device 100.

  With reference to FIG.2 and FIG.3, the electric current interruption apparatus 50 is demonstrated. The current interrupt device 50 includes a negative electrode terminal 30, a fracture plate 88, and a deformable member 80. The negative electrode terminal 30, the fracture plate 88, and the deformable member 80 are made of metal. In the case 18, a fixing portion 37 is provided on the negative electrode terminal 30. The fixing part 37 is a part of the negative electrode terminal 30. By sandwiching the case 18 between the nut 38 and the fixing portion 37, the negative electrode terminal 30 is fixed to the case 18. The fixing portion 37 (negative electrode terminal 30) is an example of a first energization member. A groove 92 and a depression 86 are provided on the side of the fracture plate 88 of the fixed portion 37. The recess 86 is provided inside the groove 92. The opposing surface 35 of the fixing portion 37 on the fracture plate 88 side faces the fracture plate 88 and is recessed toward the center. Specifically, the opposing surface 35 is inclined so as to be away from the fracture plate 88 as it goes from the end toward the center. The facing surface 35 means a surface where the deformable member 80 is not fixed among the surfaces facing the fracture plate 88 of the fixing portion 37.

  FIG. 3 shows a view of the negative electrode terminal 30 (fixed portion 37) observed from the broken plate 88 side. 3 is a schematic diagram for explaining a connection state between the fracture plate 88 and the deformable member 80, and does not accurately show the shape of the negative electrode terminal 30. FIG. For example, the above-described groove 92 and the like are not shown. As shown in FIG. 3, the end surface of the fixing portion 37 on the side of the fracture plate 88 is rectangular. The deformation member 80 is connected to one side of the rectangular end surface. Specifically, the end 80 b of the deformable member 80 is welded to the fixed portion 37. That is, a part of the periphery of the deformable member 80 is welded to the fixed portion 37. Details of the deformable member 80 will be described later.

  As shown in FIG. 2, the breaking plate 88 is disposed at a position facing the fixed portion 37 with a space from the fixed portion 37. The fracture plate 88 is an example of a second energizing member. Between the electrode assembly 52 (see also FIG. 1) and the case 18, the fracture plate 88, the deformable member 80, and the fixing portion 37 are arranged in this order above the electrode assembly 52. A groove 96 is provided on the fixing plate 37 side of the breaking plate 88. The groove 96 is formed at a position facing the groove 92. The connecting member 26 is fixed to the fracture plate 88. The fracture plate 88 is electrically connected to the negative electrode tab 20 via the connecting member 26 and the negative electrode lead 24 (see also FIG. 1). The thickness of the central portion 88a of the breaking plate 88 is thinner than the thickness of the end portion 88b. In addition, a break groove 90 is provided in the central portion 88a. The breaking groove 90 continuously makes a round at the central portion 88a.

  An insulating member 94 is disposed between the fixed portion 37 and the fracture plate 88. The insulating member 94 maintains the distance between the fixing portion 37 and the breaking plate 88. The insulating member 94 prevents the fixed portion 37 and the fracture plate 88 from coming into direct contact. That is, the insulating member 94 prevents the fixing portion 37 and the fracture plate 88 from being directly connected. A part of the insulating member 94 is located in the grooves 92 and 96. In addition, a seal member 84 is disposed outside the insulating member 94. The seal member 84 is an insulating O-ring. The seal member 84 insulates the fixing portion 37 and the fracture plate 88 and keeps the inside of the current interrupt device 50 airtight. That is, the space inside the current interrupt device 50 is blocked from the space outside the current interrupt device 50 (the space in the case 18) by the seal member 84. The seal member 84 is restricted from moving toward the deformation member 80 by the insulating member 94.

  The deformation member 80 will be described. As shown in FIG. 3, the deformation member 80 is rectangular (rectangular) when observed from the broken plate 88 side. The deformable member 80 is disposed between the fixing portion 37 and the fracture plate 88 (see also FIG. 2). One end 80 a in the longitudinal direction of the deformable member 80 is fixed to the fracture plate 88 inside the fracture groove 90. More specifically, the end portion 80 a is welded to the fracture plate 88 in a range surrounded by the fracture groove 90. The other end 80 b in the longitudinal direction of the deformable member 80 is welded to the end face of the fixed portion 37. More specifically, the end portion 80 b of the deformable member 80 is welded to the fixed portion 37 in a state where the outer edge of the end portion 80 b is in contact with the side wall of the recess 86 of the fixed portion 37. Since the deformable member 80 is connected to the fixing portion 37 and the breaking plate 88, the fixing portion 37 and the breaking plate 88 are electrically connected.

  As shown in FIG. 3, only the peripheral edge including the end 80 b among the peripheral edges of the four sides of the deformable member 80 is connected to the fixed part 37. The other three side ends (the end 80 a and both ends in the short direction) are not connected to the fixed portion 37. In the deformable member 80, a part of the periphery (end portion 80 b) is connected to the fixed part 37, and the other part of the periphery is not connected to the fixed part 37. In other words, in the circumferential direction of the portion (periphery) surrounding the center of the deformable member 80, a part of the deformable member 80 is fixed to the fixed portion 37 and the other portion is not fixed to the fixed portion 37.

  The fixing portion 37 and the fracture plate 88 are fixed by a support member 78. In other words, the support member 78 fixes the fixing portion 37 of the negative electrode terminal 30 and the fracture plate 88. The support member 78 includes a metal outer portion 72, an insulating first inner portion 74, and an insulating second inner portion 75. The first inner portion 74 is disposed inside the outer portion 72 and is disposed above the second inner portion 75 (on the lid portion 18a side). The second inner portion 75 is disposed inside the outer portion 72 and is disposed below the first inner portion 74 (on the electrode assembly 52 side). The fixing portion 37 and the breaking plate 88 are positioned by the outer portion 72. Specifically, after the first inner portion 74 and the second inner portion 75 are arranged at predetermined positions, the fracture plate 88 is fixed to the fixing portion 37 by caulking the outer portion 72. The inner portions 74 and 75 insulate the fixing portion 37 and the fracture plate 88 from each other.

  When the internal pressure of the case 18 is equal to or lower than a predetermined value, the negative electrode terminal 30 is electrically connected to the negative electrode via the deformable member 80, the fracture plate 88, the connecting member 26, the negative electrode lead 24, and the negative electrode tab 20. For example, when the power storage device 100 is overcharged, the internal pressure of the case 18 increases and may exceed a predetermined value. When the internal pressure of the case 18 exceeds a predetermined value, a pressure difference is generated between the inside and outside of the current interrupt device 50. A force is applied to the breaking plate 88, and the breaking plate 88 breaks starting from the breaking groove 90. As a result, the deformable member 80 and the breaking plate 88 are separated from each other, and the fixing portion 37 and the breaking plate 88 become non-conductive. Since the negative electrode terminal 30 and the negative electrode become non-conductive, it is possible to prevent a current from flowing between the positive electrode terminal 2 and the negative electrode terminal 30 (see also FIG. 1).

  When the fracture plate 88 is fractured, the end portion 80a of the deformable member 80 is moved from the fracture plate 88 side toward the fixed portion 37 side by the force at the time of the fracture. However, as described above, since the facing surface 35 of the fixing portion 37 is recessed, it is not hindered that the end portion 80a of the deformable member 80 moves to the fixing portion 37 side.

  Advantages of the power storage device 100 will be described. As described above, only the end 80 b of the deformation member 80 is connected to the fixed portion 37. The deformable member 80 does not apply a force that stays on the fracture plate 88 side to the end 80a. Therefore, when the breaking plate 88 is broken, the end portion 80a is easily moved to the fixed portion 37 side. Further, the deformable member 80 does not apply a pressing force to the breaker plate 88 to the outside of the current interrupt device 50 (on the electrode assembly 52 side). In other words, the deformable member 80 does not apply a force against the breaking plate 88 against the force applied to the breaking plate 88 based on the pressure difference between the inside and the outside of the current interrupt device 50. Therefore, the breaking plate 88 can be broken at a set pressure (pressure difference inside and outside the current interrupt device 50).

  For example, in the case of a current interrupting device in which the entire periphery of the deformable member is fixed to the fixing portion 37 and the central portion of the deformable member is connected to the break plate 88, the deform member is reversed when the break plate 88 breaks. As a result, the conduction between the negative electrode terminal 30 and the negative electrode is interrupted. However, a force that suppresses reversal (force that suppresses the central portion from moving toward the fixed portion 37) is applied to the deformable member. That is, a force that remains on the fracture plate 88 side is applied to the central portion of the deformable member. Therefore, even if the internal pressure of the case 18 exceeds a predetermined value and the fracture plate 88 is fractured, the central portion of the deformable member may not move to the fixed portion 37 side, and the conduction between the negative electrode terminal 30 and the negative electrode may not be interrupted. . Alternatively, when the deformable member applies a force pushing the fracture plate 88 toward the electrode assembly 52, the fracture plate 88 may not break at the set pressure (pressure difference between the inside and outside of the current interrupt device 50). In the power storage device 100, only the end 80 b of the deformable member 80 is connected to the fixed portion 37, so that the fracture plate 88 is fractured with the set pressure, and after the fracture plate 88 is fractured, the end of the deformation member 80 is broken. 80a easily moves to the fixed portion 37 side. Therefore, the power storage device 100 can improve the responsiveness of the current interrupt device 50 to the change in the internal pressure of the case 18.

  In the above embodiment, the mode in which the current interrupting device is connected to the negative electrode lead via the connecting member has been described. However, the connecting member and the negative electrode lead may be an integral part. That is, the current interrupt device may be directly connected to a member (negative electrode lead) connected to the negative electrode tab. Moreover, when the current interrupting device is disposed between the positive electrode terminal and the positive electrode, the current interrupting device may be directly connected to a member (positive electrode lead) connected to the positive electrode tab.

(Second embodiment)
With reference to FIG. 4, the electrical storage apparatus of 2nd Example is demonstrated. Note that the power storage device of this embodiment is a modification of the power storage device 100, and the shape of the deformation member 180 is different from that of the deformation member 80 of the power storage device 100. Since other structures are the same as those of the power storage device 100, illustration and description thereof are omitted. Note that FIG. 4 illustrates a portion corresponding to FIG. 3 of the power storage device 100.

  As shown in FIG. 4, the deformable member 180 covers the entire circumference of the end surface of the fixed portion 37. In other words, the deformable member 180 can connect the entire periphery of the periphery to the fixed portion 37. However, in the deformable member 180, only the periphery including the end portion 180b indicated by the solid line is connected to the fixed portion 37, and the periphery including the end portion 181b indicated by the broken line is not connected to the fixed portion 37. Specifically, of the four sides of the deformable member 180, two sides including the end 180b are welded to the fixed portion 37, and the other two sides including the end 181b are fixed to the fixed portion 37. Not welded to. In other words, in the deformable member 180, the length of the region where the end portion is connected to the fixed portion 37 is half of the entire circumference. The central portion 180a of the deformable member 180 is connected to the central portion 88a (see FIG. 2) of the fracture plate 88.

  Even if only a part of the periphery (end portion 180 b) is connected to the fixing part 37 as in the deforming member 180, the central part 180 a of the deforming member 180 is compared with the case where the entire periphery is connected to the fixing part 37. Becomes easy to move to the fixed portion 37 side (the deformable member 180 is easily reversed). Further, as compared with the case where the entire periphery is connected to the fixing portion 37, the force that the deformable member 180 pushes the fracture plate 88 toward the electrode assembly 52 can be weakened. In the deformable member 180, two of the four peripheral edges are connected to the fixed portion 37, and the other two sides are not connected to the fixed portion 37. However, it is only necessary that a part of the periphery of the deformable member 180 is not connected to the fixed portion 37, and a region not connected to the fixed portion 37 may be discontinuous. In particular, if the region where the deformable member 180 is connected to the fixed portion 37 is less than half of the entire circumference of the deformable member 180, the response of the case 18 to changes in internal pressure can be improved satisfactorily. it can.

(Third embodiment)
With reference to FIG. 5, the electrical storage apparatus of 3rd Example is demonstrated. The power storage device of this embodiment is a modification of the power storage device 100, and the shape of the negative terminal fixing portion 237 is different from the fixing portion 37 of the power storage device 100. Since other structures are the same as those of the power storage device 100, illustration and description thereof are omitted. FIG. 5 shows a portion corresponding to FIG. 3 of the power storage device 100.

  As shown in FIG. 5, the end surface of the fixing part 237 is circular. The deformation member 280 is substantially the same as the deformation member 80. An end portion 280 b of the deformable member is connected to the fixing portion 237, and the end portion 280 a is connected to the central portion 88 a of the fracture plate 88. Even if the end surface of the fixing portion 237 is circular, the same advantages as those of the current interrupt device 50 can be obtained.

(Fourth embodiment)
A power storage device according to a fourth embodiment will be described with reference to FIG. The power storage device of this embodiment is a modification of the power storage device of the third embodiment, and the shape of the deformation member 380 is different from that of the deformation member 280 of the third embodiment. That is, the shapes of the fixing portion 337 and the deformation member 380 are different from those of the fixing portion 37 and the deformation member 80 of the power storage device 100, respectively. Since other structures are the same as those of the power storage device 100, illustration and description thereof are omitted. 6 illustrates a portion corresponding to FIG. 3 of the power storage device 100.

  As shown in FIG. 6, the end surface of the fixing portion 337 is circular, and the deformable member 380 is semicircular. An end portion (arc portion of the peripheral edge) 380 b is connected to the fixing portion 337, and a central portion (intermediate portion of the straight portion of the peripheral edge) 380 a is connected to the central portion 88 a of the fracture plate 88. The end portion 380 b of the deformation member 380 is connected to approximately half of the fixing portion 337 in the circumferential direction. In the deformable member 380, the central portion 380a is easily moved to the fixed portion 337 side when the internal pressure of the case 18 is changed as compared with the case where the deformable member is circular and connected to the entire circumference of the fixed portion 337. . Even when the deformable member 380 is used, the same advantages as those of the current interrupt device 50 can be obtained.

  With reference to FIG. 7, the electrical storage apparatus of 5th Example is demonstrated. The power storage device of this embodiment is a modification of the power storage device of the fourth embodiment, and the shape of the deformation member 480 is different from that of the deformation member 480 of the fourth embodiment. That is, the shapes of the fixing portion 437 and the deformation member 480 are different from those of the fixing portion 37 and the deformation member 80 of the power storage device 100, respectively. Since other structures are the same as those of the power storage device 100, illustration and description thereof are omitted. 6 illustrates a portion corresponding to FIG. 3 of the power storage device 100.

  As shown in FIG. 7, the end surface of the fixing portion 437 is circular. The shape of the deformable member 480 is a circle. The deformable member 480 covers the entire circumference of the end surface of the fixed portion 437. The deformable member 480 can connect the entire periphery of the peripheral edge to the fixed portion 437. However, in the deformable member 480, only the periphery including the end portion 480b indicated by the solid line is connected to the fixed portion 437, and the periphery including the end portion 481b indicated by the broken line is not connected to the fixed portion 437. The length of the end portion 480b is half of the entire circumference (end portion 480b + end portion 481b). Even when the deformable member 480 is used, the same advantages as those of the current interrupt device 50 can be obtained. In the deformable member 480, the semicircular portion (end portion 481b) of the circular periphery is not connected to the fixed portion 437. However, it is sufficient that a part of the periphery of the deformable member 480 is not connected to the fixing portion 437, and a region not connected to the fixing portion 437 may be discontinuous. In particular, if the region where the deformable member 480 is connected to the fixed portion 437 is less than half of the entire circumference of the deformable member 480, the response of the case 18 to changes in internal pressure can be improved satisfactorily. it can.

  The power storage device 500 will be described with reference to FIGS. The power storage device 500 is a modification of the power storage device 100, and the structure of the current interrupt device 550 is different from the current interrupt device 50 of the power storage device 100. With respect to the power storage device 500, the same components as those of the power storage device 100 may be denoted by the same reference numerals as those of the power storage device 100, and description thereof may be omitted.

  The current interrupt device 550 of the power storage device 500 includes a second deformable member 501 in addition to the deformable member 80. In the following description, the first deformation member 80 and the second deformation member 501 are referred to. The second deformation member 501 is disposed on the opposite side of the fracture plate 88 from the first deformation member 80. That is, the fracture plate 88 is disposed between the first deformation member 80 and the second deformation member 501. The periphery including the end portion 501 b of the second deformable member 501 is fixed to the fracture plate 88. Specifically, the peripheral edge including the end portion 501 b of the second deformable member 501 is welded to the end portion 88 b of the fracture plate 88.

  In the current interrupt device 550, the fixing portion 37, the fracture plate 88, and the second deformation member 501 are supported by the support member 578. That is, the fracture plate 88 and the second deformation member 501 are fixed to the fixing portion 37 by the support member 578. The support member 578 includes an outer portion 72, a first inner portion 74, and a second inner portion 575. The second inner portion 575 covers a part of the second deformation member 501 below (opposite side of the fracture plate 88).

  An insulating protrusion 503 is provided on the broken plate 88 side of the second deformable member 501. The protrusion 503 is disposed at the central portion 501 a of the second deformable member 501 and protrudes toward the fracture plate 88. The protrusion 503 faces the central portion 88 a of the fracture plate 88. More specifically, when the current interrupt device 550 is viewed in plan (observed from the direction in which the bolt portion 36 extends, that is, from the axial direction of the negative electrode terminal 30), the range in which the protrusion 503 is surrounded by the fracture groove 90 Located in.

  When the internal pressure of the case 18 is equal to or less than a predetermined value, the second deformable member 501 is separated from the fracture plate 88 toward the center portion 501a from the end portion 501b. Therefore, a gap is provided between the protrusion 503 and the fracture plate 88 when the internal pressure of the case 18 is equal to or less than a predetermined value. When the internal pressure of the case 18 exceeds a predetermined value, the second deformation member 501 is deformed toward the fracture plate 88. That is, the central portion 501a moves toward the central portion 88a of the fracture plate 88. In other words, the second deformation member 501 is reversed with the end portion 501b as a fulcrum. The protrusions 503 come into contact with the breaking plate 88, and the breaking plate 88 breaks starting from the breaking groove 90. The fracture plate 88 and the first deformable member 80 become non-conductive, and the negative electrode terminal 30 and the negative electrode become non-conductive.

  As described above, the deformable member 80 does not apply a force pushing the fracture plate 88 toward the electrode assembly 52 side. Therefore, the deformable member 80 does not apply a force against the breaking plate 88 against the force applied from the protrusion 503 to the breaking plate 88 when the projection 503 contacts the breaking plate 88. Therefore, the breaking plate 88 can be broken at a set pressure (a pressure difference between the inside and outside of the current interrupt device 550). Further, when the second deformable member 501 is reversed, a part of the protrusion 503 is positioned above the fracture plate 88. In other words, the protrusion 503 passes through the central portion of the fracture plate 88. The protrusion 503 restricts the first deformation member 80 from moving downward (fracture plate 88 side). Therefore, it is possible to reliably prevent the first deformable member 80 and the fracture plate 88 from re-conducting.

  In the current interrupt device 550, the second deformation member 501 separates the inside and the outside of the current interrupt device 550. Therefore, the internal pressure change of the case 18 directly acts on the second deformation member 501. By using the second deformable member 501 that reverses according to the internal pressure of the case 18, the fracture plate 88 can be more reliably broken when the internal pressure of the case 18 exceeds a predetermined value. Further, by using the second deformable member 501, the fracture plate 88 can be blocked from the outside of the current interrupting device 550 (inside the case 18). Even if an arc is generated when the breaking plate 88 is broken, it is possible to prevent the arc from coming into contact with a gas (for example, hydrogen) in the case 18.

  The power storage device 600 will be described with reference to FIGS. 10 and 11. The power storage device 600 is a modification of the power storage device 100, and the structure and arrangement location of the current interrupt device 650 are different from the current interrupt device 50 of the power storage device 100. With respect to the power storage device 600, the same components as those of the power storage device 100 may be denoted by the same reference numbers as the power storage device 100 or the same reference numerals with the last two digits, and the description thereof may be omitted.

  The power storage device 600 includes a positive electrode terminal 602 and a negative electrode terminal 630. The current interrupt device 650 is disposed between the negative electrode terminal 630 and the negative electrode tab 20. Specifically, the current interrupt device 650 is connected to the negative electrode terminal 630 via the first negative electrode lead 44 and is connected to the negative electrode tab 20 via the second negative electrode lead 624. The first negative electrode lead 44 is an example of a first energization member.

  As shown in FIG. 11, the current interrupt device 650 includes a deformable member 680, a fracture plate 688, and an insulating support member 678. The shape of the deformable member 680 is rectangular and is substantially the same as the deformable member 80 (see also FIG. 3). A breaking groove 90 is provided in the central portion 688 a of the breaking plate 688. The peripheral edge including the end 688 b of the breaking plate is fixed to the support member 678. A second negative electrode lead 624 is connected to the negative electrode tab 20 side of the end portion 688b (see also FIG. 10). The first end 680 a of the deformable member 680 is connected to the central portion 688 a of the fracture plate 688. The first end portion 680 a is welded to a portion surrounded by the fracture groove 90 of the fracture plate 688. The second end 680 b of the deformation member 680 is fixed to the support member 678. The second end portion 680 b is fixed to the negative electrode terminal 602 side of the support member 678. More specifically, when the current interrupt device 650 is viewed in plan, the second end 680 b of the deformation member 680 is connected to the first negative electrode lead 44 and the negative electrode terminal 630 with respect to the center of the fracture plate 688. On the other side, it is connected to the first negative electrode lead 44. Note that the end portion 680b and the end portion 688b are insulated by a support member 678.

  In the current interrupt device 650, the deformable member 680 has a rectangular shape. However, the shape of the deformable member may be a semicircle like the deformable member 380 or a circle like the deformable member 480. In addition to the deformable member 680, a second deformable member may be provided like the current interrupt device 550.

  In the power storage device described above, a part of the periphery of the deformable member may not be connected to the first energizing member. For this reason, various structures and materials can be used for the structure of the current interrupt device and the components and materials constituting the power storage device. Hereinafter, parts and materials constituting the power storage device will be exemplified for a lithium ion secondary battery which is an example of the power storage device.

  The electrode assembly will be described. The electrode assembly includes a positive electrode, a negative electrode, and a separator interposed at a position between the positive electrode and the negative electrode. The positive electrode has a positive electrode metal foil and a positive electrode active material layer formed on the positive electrode metal foil. A positive electrode tab is corresponded to the metal foil for positive electrodes in which the positive electrode active material layer is not apply | coated. The negative electrode has a negative electrode metal foil and a negative electrode active material layer formed on the negative electrode metal foil. A negative electrode tab is corresponded to the metal foil for negative electrodes in which the negative electrode active material layer is not apply | coated. 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.

  As the metal foil for the positive electrode, aluminum (Al), nickel (Ni), titanium (Ti), stainless steel, or a composite material thereof can be used. In particular, aluminum or a composite material containing aluminum is preferable. Moreover, the material similar to the metal foil for positive electrodes can be used as a material of a positive electrode lead.

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

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

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

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

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

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

2: Positive terminal 18: Case 30: Negative terminal 37: First energization member 50: Current interrupt device 80: Deformation member 88: Breaking plate 100: Power storage device

Claims (7)

A current interrupting device that interrupts conduction between the electrode terminal and the electrode when the pressure in the case of the power storage device exceeds a predetermined value,
A first energization member connected to the electrode terminal;
A second energization member connected to the electrode;
It arrange | positions between the said 1st electricity supply member and the said 2nd electricity supply member, is connected to the said 1st electricity supply member, and when the pressure in a case is below a predetermined value, it contacts the said 2nd electricity supply member And a deformable member that is in non-contact with the second energizing member when the pressure in the case exceeds a predetermined value,
The shape of the end surface on the second energizing member side of the first energizing member is a rectangle,
A current interrupting device in which a part of the periphery of the deformable member is connected to the first energizing member, and the other part of the periphery is not connected to the first energizing member.   2. The current interrupting device according to claim 1, wherein a length of a region in which the peripheral edge is connected to the first current-carrying member is equal to or less than half of a total length of the peripheral edge. The current interrupting device according to claim 1 or 2 , wherein the deformable member is connected to one side of the rectangular end surface of the first energizing member. The current interrupting device according to any one of claims 1 to 3 , wherein the deformable member is a polygon, and only one of the sides defining the deformable member is connected to the first energizing member. apparatus. When the current interrupting device is viewed in plan, the deformable member is connected to the first energizing member on the side where the first energizing member and the electrode terminal are connected to the center of the second energizing member. The current interrupting device according to any one of claims 1 to 4 , which is connected. An electrical storage apparatus provided with the electric current interruption apparatus as described in any one of Claim 1 to 5 . The power storage device according to claim 6 , wherein the power storage device is a secondary battery.

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