JP2017027779A - Method of manufacturing power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a power storage device capable of inhibiting a joining part of a current interruption part while joining a tab group and a conductive member by ultrasonic-welding.SOLUTION: A secondary battery includes a current interruption part integrated with a negative electrode terminal. The current interruption part includes a contact point plate 81 joined to a first surface 41a in a terminal joining part 41 of a negative electrode conductive member 40. In manufacturing of the secondary battery, the contact point plate 81 and the terminal joining part 41 are joined after a negative electrode tab group 18a and a tab joining part 43 of the negative electrode conductive member 40 are joined by ultrasonic-welding.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a power storage device including a current interrupting unit.

  Conventionally, secondary batteries such as lithium ion secondary batteries have been installed in vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrid Vehicles) as power storage devices for storing electric power used in electrical components. Yes. The secondary battery includes a case, an electrode assembly housed in the case, and two electrode terminals that protrude outside the case and have different polarities. As an electrode assembly, there is an electrode assembly in which sheet-like positive electrodes and sheet-like negative electrodes are alternately laminated with a separator interposed therebetween.

  Some secondary batteries have an electrode terminal with a current interrupting part that interrupts the current in response to an increase in the internal pressure of the case. The current interrupting part is provided on an energization path that electrically connects the electrode terminal and the electrode assembly.

  As shown in FIG. 7, the current interrupting unit 90 disclosed in Patent Document 1 includes a contact plate 92 joined to a negative external terminal (electrode terminal) 89 and an energization plate (conductive member) joined to the contact plate 92. 91 and a deforming plate 93 disposed opposite to the inside of the case with respect to the energizing plate 91. The energizing plate 91 has a rectangular plate shape, and a negative electrode external terminal 89 is connected to one end along the longitudinal direction of the energizing plate 91 via a contact plate 92, and a tab provided in the electrode assembly near the other end. 98 is joined. By this energizing plate 91, the negative external terminal 89 and the electrode assembly are electrically connected.

  The energizing plate 91 has a breaking portion 91a that breaks when a predetermined load is applied. The contact plate 92 is disposed opposite to the energizing plate 91 and is electrically connected (joined) to the energizing plate 91 at a portion surrounded by the fracture portion 91a. The energization plate 91 and the contact plate 92 constitute a part of the energization path. The deformable plate 93 has a first surface facing the first space 94 a held at the same pressure as the internal pressure of the case 95, and a second space 94 b whose other surface is isolated from the internal space of the case 95. It faces the current-carrying plate 91.

  The energization plate 91, the contact plate 92, and the deformation plate 93 are fixed inside the cylindrical support member 96. Further, a sealing member 97 is disposed between the contact plate 92 and the energizing plate 91 at the periphery, and the contact plate 92 and the energizing plate 91 are insulated at the periphery. When the internal pressure of the case 95 rises above a predetermined level, the deformed plate 93 is deformed to the energizing plate 91 side as shown by the two-dot chain line in FIG. The plate 91 is broken. As a result, the energization of the energizing plate 91 and the contact plate 92 is interrupted, and the current flowing between the electrode assembly and the electrode terminal is interrupted.

JP 2014-232690 A

  By the way, at the time of manufacturing the secondary battery, the contact plate 92 is joined to the negative electrode external terminal 89 and the energizing plate 91 is joined to the contact plate 92 to form the current interrupting portion 90, and then the tab 98 is joined to the energizing plate 91. There is a way to do it. Since the tab 98 is a portion protruding from the positive electrode or the negative electrode, when the current plate 91 and the tab 98 are joined, the electrodes and the separator are easily affected by heat. For this reason, the joining of the current-carrying plate 91 and the tab 98 may be performed by ultrasonic welding for the purpose of reducing the thermal effect on each electrode or separator. However, if the current-carrying plate 91 and the tab 98 are ultrasonically welded, ultrasonic vibration propagates through the current-carrying plate 91 to the joint portion with the current interrupting portion 90 and the joint portion is damaged. There is a possibility that the function of the

  The present invention has been made paying attention to such problems existing in the prior art, and its purpose is to join the current blocking portion while joining the tab group and the conductive member by ultrasonic welding. An object of the present invention is to provide a method for manufacturing a power storage device that can prevent damage to the battery.

  A method of manufacturing a power storage device for solving the above problem is configured such that electrodes having tabs protruding from one side are stacked with electrodes having different polarities insulated from each other, and the tabs are stacked. An electrode assembly including a tab group, a case containing the electrode assembly, an electrode terminal fixed to a wall portion of the case, a conductive member constituting an energization path of the electrode assembly and the electrode terminal, A current interrupting part that interrupts the energization path between one electrode terminal and the electrode assembly when the internal pressure of the case reaches a set pressure, and the current interrupting part constitutes a part of the energization path And a contact plate connecting the electrode terminal and the conductive member, the conductive member having a tab joint joined to the tab group, and a terminal joint joined to the contact plate. Production of power storage devices A method, and with the tab group said tab joined portion after joining by ultrasonic welding, and the gist to carry out joining of the contact plate and the terminal connection region.

  According to this, the ultrasonic vibration for tab group welding does not propagate to the joint between the terminal joint and the contact plate. For this reason, it can suppress that the junction part of an electric current interruption part and a conductive member receives damage by ultrasonic vibration, and can suppress that the function of an electric current interruption part is impaired.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the junction part of an electric current interruption part receives damage, joining a tab group and an electrically-conductive member by ultrasonic welding.

Sectional drawing which shows the secondary battery of embodiment. The partial expanded sectional view which shows an electric current interruption part. The fragmentary sectional view which shows the ultrasonic welding of a negative electrode tab group and a negative electrode electrically-conductive member. The fragmentary sectional view which shows the state which joined the terminal junction part and the deformation | transformation board. The fragmentary sectional view which shows the state which integrated the terminal junction part and the supporting member. The fragmentary sectional view which shows the laser welding of a terminal junction part and a contact plate. The figure which shows background art.

Hereinafter, an embodiment in which a method for manufacturing a power storage device is embodied in a method for manufacturing a secondary battery will be described with reference to FIGS.
As shown in FIG. 1, the secondary battery 10 as a power storage device is a rectangular lithium ion secondary battery. The secondary battery 10 includes a flat square box-shaped case 11. The case 11 includes a rectangular box-shaped case main body 12 having an opening 12a, and a flat lid 13 serving as a wall covering the opening 12a of the case main body 12. The case body 12 and the lid 13 are made of metal (for example, aluminum). The case body 12 and the lid 13 are welded. The lid 13 has two through holes 13b penetrating in the thickness direction.

  The secondary battery 10 includes a rectangular parallelepiped electrode assembly 14 accommodated in a case 11. The electrode assembly 14 has a structure in which a sheet-like positive electrode and a sheet-like negative electrode are alternately stacked with a separator interposed therebetween so that they are layered. The positive electrode and the negative electrode are insulated by a resin separator.

  The positive electrode has a rectangular positive metal foil (for example, an aluminum foil) and a positive electrode active material layer on both surfaces of the positive metal foil. The positive electrode has a positive electrode tab 17 protruding from one side of the positive electrode. The negative electrode has a rectangular negative electrode metal foil (for example, copper foil) and negative electrode active material layers on both sides of the negative electrode metal foil. The negative electrode has a negative electrode tab 18 protruding from one side of the negative electrode.

  The electrode assembly 14 includes a positive electrode tab group 17a and a negative electrode tab group 18a. The positive electrode tab group 17 a and the negative electrode tab group 18 a protrude from the end surface 14 a facing the lid 13 in the electrode assembly 14. In the positive electrode tab group 17a, a plurality of positive electrode tabs 17 are layered. Similarly, in the negative electrode tab group 18a, a plurality of negative electrode tabs 18 are layered.

  The secondary battery 10 includes an electrolyte solution (not shown) accommodated in the case 11. The secondary battery 10 includes a negative electrode terminal 16 as an electrode terminal and a positive electrode terminal 15 as an electrode terminal having a polarity different from that of the negative electrode terminal 16. The positive terminal 15 and the negative terminal 16 are fixed to the lid 13 of the case 11 in a state of passing through the through hole 13 b of the lid 13. A part of the positive electrode terminal 15 and the negative electrode terminal 16 protrudes inside the case 11, and a part protrudes outside the case 11.

  The secondary battery 10 includes an insulating first seal member 20. The first seal member 20 includes a cylindrical portion 20 a fitted in the through hole 13 b through which the negative electrode terminal 16 passes, and a main body portion 20 b disposed along the inner surface of the lid 13. Further, the secondary battery 10 includes an insulating second seal member 21. The second seal member 21 includes a cylindrical portion 21 a fitted in the through hole 13 b through which the positive electrode terminal 15 passes, and a main body portion 21 b disposed along the inner surface of the lid 13.

  The negative electrode terminal 16 includes an external nut 22, an internal nut 23, and a bolt 24. The external nut 22 is used for connection between the negative electrode terminal 16 and a bus bar (not shown). The inner nut 23 is attached to the first seal member 20. A part of the inner nut 23 passes through the through hole 13b. The bolt 24 is fastened to the internal nut 23. A third seal member 25 is interposed between the bolt 24 and the lid 13. The negative electrode terminal 16 is insulated from the lid 13 by the seal members 20 and 25.

  The internal nut 23 is electrically connected to the negative electrode tab group 18 a via the current interrupting part 80 and the negative electrode conductive member 40. The negative electrode conductive member 40 includes a terminal joint portion 41 joined to the negative electrode terminal 16, a connection portion 42 continuous to the terminal joint portion 41, a tab joint portion continuous to the connection portion 42 and joined to the negative electrode tab group 18a. 43. Therefore, the negative electrode conductive member 40 constitutes an energization path between the electrode assembly 14 and the negative electrode terminal 16. The current interrupting unit 80 will be described later.

  The positive terminal 15 includes an external nut 32, an internal nut 33, and a bolt 34. The external nut 32 is used for connection between the positive terminal 15 and a bus bar (not shown). The inner nut 33 is attached to the second seal member 21. A part of the inner nut 33 passes through the through hole 13b. The bolt 34 is fastened to the internal nut 33. A fourth seal member 35 is interposed between the bolt 34 and the lid 13. The positive electrode terminal 15 is insulated from the lid 13 by seal members 21 and 35. A positive electrode conductive member 50 is fixed to the inner nut 33. The inner nut 33 and the positive electrode conductive member 50 are electrically connected. The positive electrode terminal 15 is electrically connected to the positive electrode tab group 17 a of the electrode assembly 14 through the positive electrode conductive member 50. Therefore, the positive electrode conductive member 50 constitutes an energization path between the electrode assembly 14 and the positive electrode terminal 15.

Next, the current interruption unit 80 will be described.
The current interrupting unit 80 is disposed inside the case 11, and when the internal pressure of the case 11 reaches a predetermined set pressure, the electrode assembly 14 is connected to the negative electrode terminal 16 that is one of the electrode terminals. Cut off the current in the current path that is electrically connected. The current interrupting part 80 is located at a connection part between the inner nut 23 of the negative electrode terminal 16 and the negative electrode conductive member 40.

  In this embodiment, the internal nut 23 of the negative electrode terminal 16 is electrically connected to the negative electrode conductive member 40 via the current interrupting portion 80, and the negative electrode conductive member 40 is electrically connected to the negative electrode tab group 18a. Thus, an energization path between the electrode assembly 14 and the negative electrode terminal 16 is configured.

  When the current interrupting unit 80 is activated by the gas generated inside the case 11, the current interrupting unit 80 interrupts the electrical connection between the internal nut 23 of the negative electrode terminal 16 and the negative electrode conductive member 40. That is, the current interrupting unit 80 constitutes a part of the energization path when not operating, and interrupts the energization path when operated under the pressure of the gas generated in the case 11. The current interrupting portion 80 is provided integrally with the terminal joint portion 41 of the negative electrode conductive member 40.

  As shown in FIG. 2, the current interrupting unit 80 includes a contact plate 81 connecting the terminal joint portion 41 of the negative electrode conductive member 40 and the internal nut 23 of the negative electrode terminal 16, and the contact plate 81 is an electrode assembly. 14 and a part of the energization path of the negative electrode terminal 16 are configured. The contact plate 81 is made of a conductive material and has a bowl shape that protrudes toward the electrode assembly 14. The contact plate 81 covers the female screw hole 23a of the internal nut 23 from the electrode assembly 14 side. The outer peripheral part of the contact plate 81 and the internal nut 23 are joined by laser welding. The contact plate 81 and the inner nut 23 may be joined by resistance welding or any method other than ultrasonic welding.

  The contact plate 81 is convex toward the electrode assembly 14 (downward) in a normal state, and the portion projecting toward the electrode assembly 14 and the terminal joint 41 are joined by laser welding. ing. In addition, resistance welding may be sufficient as joining of the terminal junction part 41 and the contact plate 81, and any method other than ultrasonic welding may be sufficient as it. Further, in the terminal joint portion 41, the surface near the lid 13 and the surface to which the contact plate 81 is joined is defined as a first surface 41 a, which is a surface parallel to the first surface 41 a and the surface near the electrode assembly 14. Is the second surface 41b.

  The negative electrode conductive member 40 and the internal nut 23 of the negative electrode terminal 16 are electrically connected via a contact plate 81. Since the contact plate 81 has a bowl shape, there is a gap between the internal nut 23 and the terminal joint 41 around the contact plate 81 by the amount that the contact plate 81 protrudes from the internal nut 23. The current interrupting portion 80 has an insulating ring 82 disposed in the gap between the inner nut 23 and the terminal joint portion 41. The insulating ring 82 is disposed on the outer peripheral side of the contact plate 81, surrounds the peripheral portion of the contact plate 81, and holds the internal nut 23 and the terminal joint portion 41 at a predetermined interval. A seal ring 83 is disposed on the outer peripheral side of the insulating ring 82.

  The negative electrode conductive member 40 includes a concave portion 41 c that is recessed in a mortar shape from the second surface 41 b of the terminal joint portion 41 toward the lid 13. A welded portion P between the terminal joint 41 and the contact plate 81 is located at the bottom of the recess 41c. The terminal joint portion 41 has a fracture groove 84 at a portion that becomes the bottom of the recess 41c. The fracture groove 84 has an annular shape surrounding the welded portion P.

  The current interrupting unit 80 includes a deformation plate 85 that receives the internal pressure of the case 11 and deforms. The deformation plate 85 is a diaphragm made of an elastic material, for example, a metal plate, and is disposed at a position closer to the electrode assembly 14 than the terminal joint portion 41. The deformation plate 85 has a disk shape and covers the recess 41c from the electrode assembly 14 side. The outer peripheral portion of the deformable plate 85 and the terminal joint portion 41 are joined over the entire circumference of the outer peripheral portion of the deformable plate 85. The deformation plate 85 and the terminal joint 41 are joined by laser welding. The deformation plate 85 and the terminal joint 41 may be joined by resistance welding or any method other than ultrasonic welding. The current interrupting unit 80 hermetically separates the inside of the case 11 from the outside of the case 11.

  The deformation plate 85 is convex from the lid 13 side toward the electrode assembly 14 side (downward) in the normal state, and a protrusion protruding toward the lid 13 at a location facing the welded portion P in the convex portion. 85a. The protrusion 85 a is made of an insulating material and faces the welded portion P surrounded by the fracture groove 84. In the deformable plate 85, one surface near the electrode assembly 14 receives the pressure in the internal space of the case 11, and the other surface close to the lid 13 has a pressure (atmospheric pressure) in a space isolated from the internal space in the case 11. )Is receiving. The space isolated from the internal space of the case 11 is a space surrounded by the second surface 41 b of the terminal joint portion 41 and the deformation plate 85.

  The current interrupting unit 80 includes a support member 54 that supports the inner nut 23, the terminal joint 41, and the contact plate 81. The support member 54 is made of a thermoplastic resin (for example, PPS). The support member 54 has a cylindrical shape, and a part of the inner nut 23, the contact plate 81, the terminal joint portion 41, the insulating ring 82, and the seal ring 83 are accommodated therein. In the support member 54, the surface facing the lid 13 is in contact with the inner surface of the lid 13. In the support member 54, a protruding piece 54 e that protrudes toward the inner nut 23 is formed on the inner peripheral edge near the lid 13. The protruding piece 54 e is in contact with the inner nut 23. The support member 54 includes a caulking boss 54 a, and the caulking boss 54 a protrudes toward the electrode assembly 14. The caulking bosses 54 a are present at the four corners of the surface of the support member 54 facing the electrode assembly 14.

  The terminal joint 41 is fixed to the support member 54 by caulking with the caulking boss 54a. By fixing the terminal joint portion 41 to the support member 54, the support member 54 supports the contact plate 81 and the terminal joint portion 41 in a stacked state.

  In the secondary battery 10 including the current interrupting unit 80 having the above-described configuration, the internal pressure of the case 11 increases when gas is generated in the electrode assembly 14 during overcharge / overdischarge. When the internal pressure reaches the set pressure, the deformed plate 85 receiving the pressure is deformed so as to be convex toward the welded portion P. Then, the projection 85 a collides with the welded portion P surrounded by the fracture groove 84, the welded portion P in the negative electrode conductive member 40 is broken, and the contact plate 81 is deformed toward the lid 13. As a result, the contact plate 81 and the negative electrode conductive member 40 are separated from each other, so that the electrical connection between the negative electrode conductive member 40 and the negative electrode terminal 16 is physically interrupted, and the electrode assembly 14 and the negative electrode terminal 16 are disconnected. The current flowing between them is interrupted.

Next, the manufacturing method of the secondary battery 10 will be described together with the operation.
The manufacturing method of the secondary battery 10 includes a manufacturing process of the electrode assembly 14, a bonding process of the positive electrode tab group 17a and the positive electrode conductive member 50, a bonding process of the negative electrode tab group 18a and the negative electrode conductive member 40, and negative electrode conduction. And integrating the current interrupting part 80 with the member 40. Further, the method for manufacturing the secondary battery 10 includes a step of fixing the positive electrode terminal 15 and the negative electrode terminal 16 to the lid 13 and a step of fixing the lid 13 to the case body 12.

  First, in the manufacturing process of the electrode assembly 14, the sheet-like positive electrode and the sheet-like negative electrode are alternately stacked with a separator interposed therebetween to manufacture the electrode assembly 14, A positive electrode tab group 17a in which the positive electrode tabs 17 are stacked and a negative electrode tab group 18a in which the negative electrode tabs 18 are stacked are manufactured. In the joining step of the positive electrode tab group 17a and the positive electrode conductive member 50, the positive electrode tab group 17a and the positive electrode conductive member 50 are joined by ultrasonic welding. In the joining step of the negative electrode tab group 18a and the negative electrode conductive member 40, the tab joint portion 43 of the negative electrode conductive member 40 and the negative electrode tab group 18a are joined by ultrasonic welding.

  As shown in FIG. 3, the negative electrode tab group 18 a is superposed on the tab joint portion 43 of the negative electrode conductive member 40, and the tab joint portion 43 and the negative electrode tab group 18 a are sandwiched by a horn 44 for ultrasonic welding. Then, ultrasonic vibration is applied to the tab joint 43 and the negative electrode tab group 18 a by the pair of horns 44, and the negative electrode tab group 18 a and the tab joint 43 are welded.

  After joining the tab groups 17a and 18a, the negative electrode conductive member 40 is provided with a current interrupting portion 80. First, as shown in FIG. 4, the outer peripheral part of the deformation | transformation board 85 is joined to the 2nd surface 41b of the terminal junction part 41 by laser welding.

  Next, as shown in FIG. 5, after the outer peripheral portion of the contact plate 81 is joined to the internal nut 23 by laser welding, the internal nut 23 and the contact plate 81 are accommodated inside the support member 54. Next, after the insulating ring 82 and the seal ring 83 are accommodated inside the support member 54, the terminal joint portion 41 and the support member 54 are assembled together, and the caulking boss 54 a of the support member 54 penetrates the terminal joint portion 41. Let Next, heat is applied to the caulking boss 54a protruding from the terminal joint 41 by a heater chip (not shown). Then, the caulking boss 54 a is thermally deformed, and the terminal joint portion 41 is integrated with the support member 54. That is, the support member 54 and the terminal joint portion 41 of the negative electrode conductive member 40 are integrated by heat caulking.

  After that, as shown in FIG. 6, the laser welder 45 irradiates the laser from the first surface 41 a side of the terminal joint portion 41 through the female screw hole 23 a of the inner nut 23, and the terminal joint portion 41 and the contact plate 81. Are joined by laser welding to form a welded portion P, whereby the current interrupting portion 80 is completed.

  In the step of fixing the positive electrode terminal 15 and the negative electrode terminal 16 to the lid 13, the bolt 34 penetrating the through hole 13 b is fastened to each internal nut 23, 33, and the positive electrode terminal 15 and the negative electrode terminal 16 are fixed to the lid 13. To do. At this time, the positive electrode terminal 15 and the negative electrode terminal 16 and the lid 13 are insulated by the first to fourth seal members 20, 21, 25 and 35. Finally, the lid 13 is fixed to the case body 12 to form the case 11, and the secondary battery 10 is completed.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) In the manufacture of the secondary battery 10, after joining the negative electrode tab group 18 a and the negative electrode conductive member 40 by ultrasonic welding, joining the terminal joint portion 41 and the deformation plate 85 in the current interrupting portion 80, The contact plate 81 and the inner nut 23 are joined, and the terminal joint portion 41 and the contact plate 81 are joined. For this reason, the ultrasonic vibration at the time of joining the negative electrode tab group 18 a and the tab joint portion 43 is propagated to each joint portion of the current interrupting portion 80, particularly to the welded portion P between the terminal joint portion 41 and the contact plate 81. In addition, each joint portion is not damaged by vibration, and the function of the current interrupting portion 80 is not impaired.

  As a result, in the current interrupting unit 80, when the internal pressure of the case 11 exceeds the set pressure, the deforming plate 85 is normally deformed, and when the deforming plate 85 is deformed, the contact plate 81 is normally deformed to Can be shut off.

  (2) In the manufacture of the secondary battery 10, after joining the negative electrode tab group 18 a and the negative electrode conductive member 40 by ultrasonic welding, the caulking boss 54 a of the support member 54 is thermally deformed to form the support member 54. The negative electrode conductive member 40 was integrated. For this reason, the ultrasonic vibration at the time of joining the negative electrode tab group 18a and the tab joint part 43 does not propagate to the crimping part of the electric current interruption part 80 and the negative electrode electrically-conductive member 40, and a crimping part is damaged by vibration. And the current interrupting part 80 is not damaged.

  (3) The negative electrode tab group 18a and the negative electrode conductive member 40, and the positive electrode tab group 17a and the positive electrode conductive member 50 were joined by ultrasonic welding. Ultrasonic welding requires less heat for welding than laser welding or resistance welding. For this reason, when the tab groups 17a, 18a and the conductive members 40, 50 are joined, the thermal effect on the electrode assembly 14 can be reduced. Therefore, damage to the positive electrode and the negative electrode due to heat is suppressed, and the separator can be prevented from melting due to heat.

In addition, you may change this embodiment as follows.
In the embodiment, after the negative electrode tab group 18a and the negative electrode conductive member 40 are joined by ultrasonic welding, the terminal joint portion 41 and the deformed plate 85 are joined, the contact plate 81 and the internal nut 23 are joined, and The terminal joining portion 41 and the contact plate 81 are joined. However, the joining order is not limited to this.

  For example, after joining the inner nut 23 and the contact plate 81 and joining the deformable plate 85 and the terminal joint portion 41, ultrasonic welding is performed between the negative electrode tab group 18a and the negative electrode conductive member 40, and this ultrasonic welding is performed. Later, the terminal joint portion 41 and the contact plate 81 may be joined.

  The integration of the support member 54 and the negative electrode conductive member 40 may be performed by thermally deforming the caulking boss 54a with ultrasonic waves. In this case, the deformation plate 85 is joined to the terminal joining portion 41 and the contact plate 81 is joined to the internal nut 23 by laser welding, and then the internal nut 23 and the contact plate 81 are accommodated inside the support member 54. Next, after the insulating ring 82 and the seal ring 83 are accommodated inside the support member 54, the terminal joint portion 41 and the support member 54 are assembled together, and the caulking boss 54 a of the support member 54 penetrates the terminal joint portion 41. Let

  First, the caulking boss 54 a protruding from the terminal joint portion 41 is thermally deformed by ultrasonic waves, and the terminal joint portion 41 is integrated with the support member 54. Thereafter, the terminal joint 41 and the contact plate 81 are joined by laser welding.

When comprised in this way, an ultrasonic vibration will not propagate to the welding part P in the electric current interruption part 80, and the welding part P will not be damaged.
A current interrupting unit 80 may be provided on the positive terminal 15.

(Circle) the positive electrode terminal 15 and the negative electrode terminal 16 may be comprised with the bolt-shaped thing single-piece | unit instead of the structure which integrated the external nut, the internal nut, and the volt | bolt.
The specific configuration of the current interrupting unit 80 may be changed. For example, the fracture groove 84 may not be annular, but may be a recess provided on the outside of the welded portion P with a gap.

  The specific configuration of the electrode assembly 14 may be changed. For example, the shapes of the positive electrode, the negative electrode, and the separator may be changed. For example, the square may be a front view, and the separator may be a bag that wraps the positive electrode. Furthermore, the electrode assembly 14 may be a wound electrode assembly in which a strip-shaped positive electrode and a strip-shaped negative electrode are wound with a separator interposed therebetween.

The embodiment can be applied to a power storage device other than the secondary battery such as a capacitor.
The secondary battery 10 is not limited to being mounted on a vehicle, but may be a stationary battery used in a house or the like.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

  (A) The current interrupting portion is a deformation plate that receives the pressure of the internal space of the case on one surface and receives the pressure of the space isolated from the internal space of the case on the other surface, A deformation plate bonded to a surface of the bonding portion near the electrode assembly; after the tab group and the tab bonding portion are bonded by ultrasonic welding, and between the terminal bonding portion and the contact plate A method for manufacturing a power storage device, comprising joining the terminal joining portion and the deformation plate and joining the electrode terminal and the contact plate before joining.

  (B) The current interrupting portion is a deformation plate that receives the pressure of the internal space of the case on one surface and receives the pressure of the space isolated from the internal space of the case on the other surface, A deformation plate bonded to a surface of the bonding portion near the electrode assembly; and after the bonding between the terminal bonding portion and the deformation plate and the bonding between the electrode terminal and the contact plate, the tab A method of manufacturing a power storage device in which a group and the tab joint are joined by ultrasonic welding, and then the electrode terminal and the contact plate are joined.

(C) A method of manufacturing a power storage device including a support member that supports the electrode terminal, the contact plate, and the terminal joint, wherein the support member and the terminal joint are integrated by thermal caulking.
(D) A method of manufacturing a power storage device that performs the thermal caulking after welding of a joint included in the current interrupting unit.

  (E) A method of manufacturing a power storage device in which joining of the electrode terminal and the contact plate, and joining of the terminal joint and the deformation plate are performed by laser welding.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as a power storage device, 11 ... Case, 13 ... Lid as wall, 14 ... Electrode assembly, 15 ... Positive electrode terminal as electrode terminal, 16 ... Negative electrode terminal as electrode terminal, 17 ... As tab Positive electrode tab, 17a ... positive electrode tab group as a tab group, 18 ... negative electrode tab as a tab group, 18a ... negative electrode tab group as a tab group, 40 ... negative electrode conductive member as a conductive member, 41 ... terminal joint, 43 ... Tab junction, 50 ... positive electrode conductive member as conductive member, 80 ... current interrupting part, 81 ... contact plate.

Claims (1)

An electrode assembly including a tab group in which electrodes having tabs protruding from one side are stacked in a state where electrodes of different polarities are insulated from each other, and the tabs are stacked,
A case containing the electrode assembly;
An electrode terminal fixed to the wall of the case;
A conductive member constituting an energization path of the electrode assembly and the electrode terminal;
When the internal pressure of the case reaches a set pressure, it has a current cut-off portion that cuts off the energization path between one electrode terminal and the electrode assembly,
The current interrupting portion comprises a contact plate that constitutes a part of the energization path and connects the electrode terminal and the conductive member;
The conductive member has a tab joint joined to the tab group, and a method of manufacturing a power storage device having a terminal joint joined to the contact plate,
A method of manufacturing a power storage device, comprising: joining the terminal joint and the contact plate after joining the tab group and the tab joint by ultrasonic welding.

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