JP2014157792A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to prevent a power storage device to be conducted again after current conduction of the power storage device is interrupted.SOLUTION: The power storage device includes: a case; an electrode assembly accommodated in the case; an electrode terminal provided in the case; and a current interrupting device which is fixed to the case and interrupts a current conduction path between the electrode assembly and the electrode terminal. The current interrupting device includes: a diaphragm which is deformed by receiving a pressure inside the case; and a current conduction member which interrupts the current conduction path by being divided into a first current conduction part and a second current conduction part when the diaphragm is deformed due to increase of a pressure inside the case. At least a part of the diaphragm is formed of a magnetic body, or the magnetic body is bonded to at least a part of the diaphragm. Further, the current interrupting device includes a magnet fixed to the case. The magnet is, with respect to the diaphragm, arranged at the side in which the diaphragm is deformed when the pressure inside the case increases.

Description

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

  The power storage device may be equipped with a current interrupt device to improve safety. In the power storage device of Patent Document 1, positive and negative electrodes are housed in a can and sealed. The current interrupting device mounted on the power storage device interrupts the current flowing between the electrode and the external load when the internal pressure of the can rises. In the current interrupting device, a conductive current interrupting valve and a bridge are joined to form a part of an energization path between the electrode and an external load. One side of the current cutoff valve receives the pressure inside the can. One end of the bridge is fixed to the current cutoff valve, and the other end is fixed to the can. When the pressure of the can rises, the current cutoff valve is deformed. As a result, the bridge fixed to the current cutoff valve is broken and the energization path is interrupted.

Patent No. 4644483

  However, in the power storage device, vibrations, impacts, and the like may be applied from the outside after the current interrupt device is activated and the power supply is interrupted. In the power storage device of Patent Document 1, when vibration, impact, or the like is applied, the deformation of the current cutoff valve may return to the original state, and the broken bridge may come into contact again. In other words, in the power storage device disclosed in Patent Document 1, there is a possibility that the power storage device may be energized again when vibration or impact is applied after the energization is interrupted.

  The present specification provides a technique for solving the above-described problems. This specification provides a technique for suppressing re-energization after the energization of the power storage device is interrupted.

  A power storage device disclosed in the present specification includes a case, an electrode assembly housed in the case, an electrode terminal provided in the case, and being fixed to the case, and between the electrode assembly and the electrode terminal. A current interrupting device that interrupts the energization path. The current interrupt device includes a partition wall that is deformed by receiving the pressure in the case, and a current path by being separated into a first conductive portion and a second conductive portion when the pressure in the case is increased and the partition wall is deformed. And a conductive member that shuts off. At least a part of the partition is made of a magnetic material, or a magnetic material is bonded to at least a part of the partition. The current interrupt device further includes a magnet fixed to the case. The magnet is arranged on the side where the partition wall deforms when the pressure in the case rises with respect to the partition wall.

  In the above power storage device, when the pressure in the case increases and the partition wall is deformed, the distance between the partition wall and the magnet is reduced. As a result, the attractive force that the magnet fixed to the case attracts the partition wall is increased. This prevents the deformed partition wall from returning to its original state. Accordingly, it is possible to prevent the power storage device from being energized again after the current interrupting device interrupts the power storage device. Note that in a state where the pressure in the case is low and the partition wall is not deformed, the distance between the partition wall and the magnet is large, and the attractive force with which the magnet attracts the partition wall is weak. For this reason, the partition is not deformed by the attractive force of the magnet before the pressure in the case rises to a predetermined pressure.

  According to the power storage device disclosed in the present specification, it is possible to prevent the power supply device from being energized again after the current interrupting device interrupts the power storage device.

Sectional drawing which shows the whole structure of the electrical storage apparatus 2 of 1st Example. The partial expanded sectional view of the electric current interruption apparatus 40 (less than electric current interruption pressure value) of 1st Example. The partial expanded sectional view of the electric current interruption apparatus 40 (above electric current interruption pressure value) of 1st Example. The partial expanded sectional view of the electric current interruption apparatus 140 (above electric current interruption pressure value) of 2nd Example. The partial expanded sectional view of the electric current interruption apparatus 240 (above electric current interruption pressure value) of 3rd Example. The partial expanded sectional view of the electric current interruption apparatus 340 (less than electric current interruption pressure value) of 4th Example. The partial expanded sectional view of the electric current interruption apparatus 340 (above electric current interruption pressure value) of 4th Example. The partially expanded sectional view of the electric current interruption apparatus 202 (less than electric current interruption pressure value) of the other 1st form. The partial expanded sectional view of the electric current interruption apparatus 202 (more than electric current interruption pressure value) of the other 1st form. The partial expanded sectional view of the electric current interruption apparatus 402 (less than electric current interruption pressure value) of the other 3rd form. The partial expanded sectional view of the electric current interruption apparatus 402 (more than electric current interruption pressure value) of the other 3rd form.

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

(Characteristic 1) In the power storage device disclosed in the present specification, the magnet may be located at a position overlapping the projected partition when the partition is projected in a direction in which the partition is deformed.

  In the above-described power storage device, an attractive force that the magnet attracts the partition is effectively generated. Thereby, it can prevent effectively that a deformation | transformation of a partition returns.

(Characteristic 2) In the power storage device disclosed in the present specification, the current interrupt device is fixed to the inside of the wall of the case, and the magnet may be positioned between the wall of the case and the partition wall.

  For example, when the magnet is disposed outside the case, the attractive force may be reduced due to the presence of the case wall between the magnet and the partition wall. In the above power storage device, the magnet is disposed between the wall of the case and the partition wall. For this reason, the attractive force which a magnet attracts | sucks a partition generate | occur | produces effectively. Thereby, it can prevent effectively that a deformation | transformation of a partition returns.

(Feature 3) In the power storage device disclosed in this specification, the magnetic body is iron.

  In the above power storage device, a magnetic force can be generated between the iron and the magnet. Thereby, it can prevent that a deformation | transformation of a partition returns.

  The power storage device 2 of the first embodiment is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The power storage device 2 is mounted on a vehicle such as a hybrid vehicle or an electric vehicle, and supplies power to the motor. In addition, the power storage device 2 is charged with electric power regenerated by the motor.

  As shown in FIG. 1, the power storage device 2 includes a case 4, an electrode assembly 6 accommodated in the case 4, a positive terminal 12 a and a negative terminal 12 b as electrode terminals provided in the case 4, and a case 4. A current interrupting device 40 provided therein is provided.

  The case 4 is made of metal and has a substantially rectangular parallelepiped shape. The upper wall 4a of the case 4 is provided with a positive terminal 12a at the right end in FIG. 1 and a negative terminal 12b at the left end in FIG. The positive electrode terminal 12a and the negative electrode terminal 12b are electrically connected to the positive electrode and the negative electrode, respectively, in the case 4 (described in detail later). The positive terminal 12 a and the negative terminal 12 b exchange electricity with the electrode assembly 6. A wiring member (not shown) for charging / discharging the power storage device 2 is connected to the positive electrode terminal 12a and the negative electrode terminal 12b.

  As shown in FIG. 1, the positive terminal 12a includes a metal bolt 24a, an inner nut 26a, and an outer nut 28a. The bolt 24a and the inner nut 26a are attached to the case 4 via a seal washer 32a. The bolt 24a and the inner nut 26a are insulated from the case 4 by an insulating sleeve 30a. The outer nut 28a is used for connection with a wiring member.

  The negative electrode terminal 12b includes a metal bolt 24b, an inner nut 26b, and an outer nut 28b. The bolt 24b and the inner nut 26b are attached to the case 4 via a seal washer 32b. The bolt 24b and the inner nut 26b are insulated from the case 4 by an insulating sleeve 30b. The outer nut 28b is used for connection with a wiring member.

  The electrode assembly 6 includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode (not shown). Each of the positive electrode and the negative electrode has a metal foil and an active material layer formed on the metal foil (not shown). A positive electrode tab 55a and a negative electrode tab 55b extend from the positive or negative metal foil.

The electrode assembly 6 is immersed in a liquid electrolyte. The electrolytic solution contains a supporting salt containing a lithium salt in a solvent. For example, FEC (fluoroethylene carbonate) can be used as the solvent. As the supporting salt, for example, LiPF ₆ (lithium hexafluorophosphate) can be used. The electrolyte contains an aromatic monomer additive. When an overvoltage is applied to the electrode assembly 6, the monomer additive contained in the electrolyte is polymerized to generate hydrogen gas. As a result, the pressure in the internal space 41 of the case 4 is increased.

  As shown in FIG. 1, the positive electrode tab 55a, the 1st lead | lead 10a, and the positive electrode terminal 12a are connected in order, and the electricity supply path which connects a positive electrode and the positive electrode terminal 12a is formed. An insulating sheet 34 a is disposed between the upper surface of the first lead 10 a and the inner surface of the upper wall 4 a of the case 4. By connecting the negative electrode tab 55b, the second lead 10b, the current interrupt device 40, the conductive member 14, and the negative electrode terminal 12b in this order, an energization path that connects the negative electrode and the negative electrode terminal 12b is formed. When the pressure in the case 4 rises, the current interrupt device 40 interrupts this energization path.

  The current interrupt device 40 is fixed to the inner surface of the upper wall 4 a of the case 4. An insulating sheet 34 b is disposed between the upper surface of the second lead 10 b and the upper end portion of the current interrupt device 40 and the inner surface of the upper wall 4 a of the case 4. The current interrupt device 40 is a pressure-sensitive current interrupt device. When the pressure in the case 4 is less than the current interrupt pressure value, the current interrupt device 40 sets the current to flow through the energization path between the negative electrode and the negative electrode terminal 12b. Further, when the pressure in the case 4 is equal to or higher than the current interruption pressure value, the current interruption device 40 interrupts the energization path between the negative electrode and the negative electrode terminal 12b so that no current flows.

  Below, the electric current interruption apparatus 40 is demonstrated in detail. The current interrupt device 40 changes from the state shown in FIG. 2 (the pressure in the case 4 is less than the current interrupt pressure value) to the state shown in FIG. 3 (the state in which the pressure in the case 4 is equal to or greater than the current interrupt pressure value). Thus, the energization path between the negative electrode and the negative electrode terminal 12b is interrupted.

  As shown in FIG. 2, the current interrupt device 40 includes a partition wall 38. The partition wall 38 is formed of a circular thin plate as viewed from above in FIG. The partition wall 38 is a so-called diaphragm. The partition wall 38 is made of a material that is conductive and magnetic. As a material for forming the partition wall 38, for example, iron can be used.

  The partition wall 38 receives the pressure of the internal space 41 in the case 4 on the lower surface, and receives the pressure of the space 42 that is a space isolated from the internal space 41 in the case 4 on the upper surface. Yes. The partition wall 38 includes an outer peripheral edge portion 72 positioned on the outer peripheral portion of the partition wall 38 and a partition wall displacement portion 73 positioned on the inner side of the outer peripheral edge portion 72. The partition wall displacement portion 73 will be described in detail later. The partition 38 bulges downward as shown in FIG. 2 when the pressure in the case 4 is less than the current cutoff pressure value. The outer peripheral edge 72 of the partition wall 38 is sandwiched between the second lead 10b and the insulating support member 36.

  The second lead 10 b has an opening 11. The opening 11 is located in an inner portion of the portion sandwiching the outer peripheral edge 72 of the partition wall 38. The partition wall 38 has a central flat portion 76 at the center thereof. The upper surface of the outer peripheral edge 72 of the partition wall 38 and the lower surface of the second lead 10b are in contact with each other, and both are electrically connected.

  The conductive member 14 is supported by the support member 36 on the lower side of the partition wall 38 (the side receiving the pressure in the case 4). The outer peripheral edge 72 of the partition wall 38 and the conductive member 14 are insulated by a support member 36 having an insulating property. The lower surface of the central flat portion 76 of the partition wall 38 and the upper surface of the conductive member 14 are fixed and electrically connected. The central flat portion 76 of the partition wall 38 and the conductive member 14 are welded at a welded portion 78. A vent hole 37 is provided in the support member 36. The ventilation hole 37 communicates the space inside the support member 36 (specifically, the space below the partition wall 38) and the space in which the electrode assembly 6 is accommodated. In the following description, the space inside the support member 36 (the space below the partition wall 38) may be simply referred to as the internal space 41 in the case 4.

  A weakened portion 20 is formed on the lower surface of the conductive member 14. The fragile portion 20 has an arc shape when viewed from the top of FIG. The fragile portion 20 is formed so as to surround the welded portion 78 when viewed from above in FIG. The fragile portion 20 is a groove having a triangular cross section and is formed by engraving. The conductive member 14 includes a moving side conductive portion 17 located inside the fragile portion 20 and a fixed side conductive portion 16 located outside the fragile portion 20. The moving side conductive portion 17 and the fixed side conductive portion 16 are adjacent to each other.

  The second lead 10b, the partition wall 38, and the conductive member 14 are electrically connected in this order, so that a current flows through the energization path between the negative electrode and the negative electrode terminal 12b.

  The current interrupt device 40 includes a magnet 80. As the magnet 80, for example, a ferrite magnet can be used. As shown in FIGS. 2 and 3, the magnet 80 is fixed inside the upper wall 4 a of the case 4. The magnet 80 is sandwiched between the upper wall 4a of the case 4 and the insulating sheet 34b. The magnet 80 is disposed in the upper part of FIG. When viewed from above in FIG. 2, the magnet 80 is disposed at a position where the center of the magnet 80 coincides with the center of the partition wall 38. In other words, the magnet 80 is disposed at a position where the partition wall 38 and the magnet 80 overlap when the partition wall 38 is projected upward.

  As shown in FIG. 3, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the conductive member 14 is broken at the weakened portion 20. As a result, the partition wall displacement portion 73 and the moving side conductive portion 17 are integrally moved upward. The partition wall 38 is deformed as the partition wall displacement portion 73 moves upward. The partition wall 38 changes from the above-described bulging state (FIG. 2) to the bulging state (FIG. 3). When the conductive member 14 is broken, a current does not flow in the energization path between the negative electrode and the negative electrode terminal 12b.

  The pressure receiving area of the partition wall 38 and the breaking strength of the conductive member 14 are designed so that the conductive member 14 breaks at the current cutoff pressure value.

  In the power storage device 2 of the present embodiment, as described above, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the partition wall displacement portion 73 moves upward. For this reason, the distance between the partition wall 38 and the magnet 80 is shortened. (In detail, the distance between the partition wall displacement portion 73 of the partition wall 38 and the magnet 80 is shortened.) As a result, the magnetic force acting between the partition wall 38 and the magnet 80 is increased. That is, the attraction force by which the magnet 80 attracts the partition wall 38 is increased. For this reason, after the partition wall 38 is deformed, the partition wall displacement portion 73 of the partition wall 38 is prevented from moving downward again. That is, the deformed partition wall 38 is prevented from returning. Accordingly, it is possible to prevent the power storage device 2 from being energized again after the current interrupt device 40 interrupts the power storage device 2. Note that, in a state where the pressure in the case 4 is low and the partition wall 38 is not deformed, the distance between the partition wall 38 and the magnet 80 is large, and the attractive force for the magnet 80 to attract the partition wall 38 is weak. For this reason, the partition wall 38 is not deformed by the attractive force of the magnet 80 before the pressure in the case 4 rises to a predetermined pressure.

  Further, in the power storage device 2 of the present embodiment, the magnet 80 is disposed at a position overlapping the partition wall 38 when the partition wall 38 is projected. For this reason, a magnetic force acts effectively between the magnet 80 and the partition wall 38. Thereby, it can suppress effectively that a deformation | transformation of the partition 38 returns.

  In the power storage device 2 of the present embodiment, the current interrupt device 40 is fixed inside the case wall 4a. The magnet 80 is disposed between the case wall 4 a and the partition wall 38. For example, when the magnet 80 is disposed outside the case 4, the case wall 4 a is positioned between the magnet 80 and the partition wall 38, and the magnetic force acting between the magnet 80 and the partition wall 38 is weakened. In contrast, in the power storage device 2 of the present embodiment, the magnet 80 is disposed between the case wall 4 a and the partition wall 38. Thereby, a magnetic force can be made to act effectively between the magnet 80 and the partition 38, and it can prevent effectively that a deformation | transformation of the partition 38 returns.

  In the power storage device 2 of the present embodiment, the partition wall 38 is formed of iron that is a magnetic material. For this reason, in the electrical storage apparatus 2 of a present Example, magnetic force can be effectively generated between the iron and the magnet 80 which are magnetic bodies. Thereby, it can prevent effectively that a deformation | transformation of the partition 38 returns.

  In the power storage device 2 of the present embodiment, as described above, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the partition wall displacement portion 73 moves upward. At this time, an elastic force may be generated in the partition wall 38. The elastic force acts in the direction in which the partition wall displacement portion 73 is moved downward (that is, the direction in which the partition wall displacement portion 73 is prevented from moving upward). The magnitude of the elastic force increases as the amount by which the partition wall displacement portion 73 moves upward increases. On the other hand, the magnetic force acting between the magnet 80 and the partition wall 38 acts in a direction opposite to the elastic force (direction in which the partition wall displacement portion 73 is moved upward). The magnitude of the magnetic force increases as the amount by which the partition wall displacement portion 73 moves upward is increased. Thereby, an elastic force and a magnetic force can be balanced and it can suppress effectively that a deformation | transformation of the partition 38 returns.

  The material (specifically, for example, iron) forming the partition wall 38 of the present embodiment is a magnetic body and a conductor. For this reason, the partition wall 38 can generate a magnetic force, and the partition wall 38 can constitute a part of the energization path between the negative electrode terminal 12 b and the electrode assembly 6.

  The magnetic flux density, shape and size of the magnet 80, the distance between the magnet and the partition, and the like are designed in advance. For example, the magnetic flux density of the magnet 80 may be designed so that the attractive force with which the magnet 80 attracts the partition wall 38 is larger than the gravity acting on the partition wall 38 when the partition wall 38 bulges upward. . Alternatively, the magnetic flux density of the magnet 80 is such that the attractive force that the magnet 80 attracts the partition wall 38 in the state where the partition wall 38 bulges upward is the direction in which the gravity acting on the partition wall 38 and the deformation of the partition wall 38 are restored. It may be designed so as to be larger than the size obtained by adding the elastic force of the partition wall 38.

  As described above, in Example 1, the current interrupt device 40 was fixed to the case 4. When the current interrupt device 40 is fixed to the case 4, the current interrupt device 40 may be indirectly fixed to the case 4 via another member. In the first embodiment, the magnet 80 is fixed to the case 4. When the magnet 80 is fixed to the case 4, the magnet 80 may be indirectly fixed to the case 4 via another member.

  The power storage device 2 according to the second embodiment differs from the first embodiment in the position where the magnet 80 is disposed (FIG. 4). In the second embodiment, the magnet 80 is disposed outside the upper wall 4 a of the case 4. Thereby, attachment / detachment of the magnet 80 to / from the power storage device can be facilitated.

  The power storage device 2 according to the third embodiment also differs from the first embodiment in the position where the magnet 80 is disposed (FIG. 5). In the third embodiment, the magnet 80 is disposed inside the upper wall 4a of the case 4 and inside the insulating sheet 34b (lower side in FIG. 5). Thereby, it can suppress that the magnetic force between the magnet 80 and the partition 38 is prevented by the insulating sheet 34b.

  The correspondence between the first to third embodiments and the claims will be described. The conductive member 14 in this embodiment is an example of the “conductive member” in the claims, the moving-side conductive portion 17 is an example of the “first conductive portion” in the claims, and the fixed-side conductive portion 16 is in the claims. It is an example of a “second conductive part”.

  The power storage device 2 of the fourth embodiment is obtained by changing the current interrupt device 40 of the power storage device 2 of the first embodiment to a current interrupt device 340 (FIGS. 6 and 7). The end of the second lead 10b on the right side in FIG. 6 is connected to the negative electrode tab 55b (see FIG. 1) similarly to the current interrupt device 40 of the first embodiment. Further, the end of the third lead 22 on the left side in FIG. 6 is connected to the negative electrode terminal 12b at a position not shown. By connecting the negative electrode tab 55b, the second lead 10b, the current interrupt device 340, the third lead 22, and the negative electrode terminal 12b (see FIG. 1) in this order, an energization path that connects the negative electrode and the negative electrode terminal 12b is formed. ing. When the pressure in the case 4 rises, the current interrupt device 340 interrupts this energization path (described in detail later).

  Hereinafter, the current interrupting device 340 will be described in detail. As shown in FIG. 6, the current interrupt device 340 includes a partition wall 538. The partition wall 538 is a circular conductive diaphragm as viewed from above in FIG. The partition 538 is formed of a magnetic material. As a material for forming the partition wall 538, for example, iron can be used.

  The partition wall 538 includes an outer peripheral edge portion 572 positioned on the outer peripheral portion of the partition wall 538 and a partition wall displacement portion 573 positioned on the inner side of the outer peripheral edge portion 572. The partition wall displacement portion 573 will be described in detail later. The outer peripheral edge 572 of the partition wall 538 is sandwiched between the second lead 10 b and the support member 36. The outer peripheral edge 572 of the partition wall 538 and the second lead 10b are in contact with each other, and both are electrically connected. The third lead 22 is supported by the support member 36 below the partition wall 538. The edge of the partition wall 538 and the third lead 22 are insulated by the support member 36. The partition wall 538 receives the pressure of the space 41 in the case 4 on the lower surface. The upper surface receives the pressure of a space 42 that is a space isolated from the space in the case 4.

  As in the first embodiment, a magnet 80 is disposed inside the upper wall 4a of the case 4 (FIGS. 6 and 7). Specifically, the magnet 80 is disposed between the upper wall 4a of the case 4 and the above-described insulating sheet 34b.

  The partition wall 538 can be deformed between the state shown in FIG. 6 (the state bulging downward) and the state shown in FIG. 7 (the state bulging upward) according to the pressure in the space 41. . That is, when the pressure in the case 4 is less than the current interruption pressure value, the partition wall 538 bulges downward (FIG. 6). In this state, the portion bulging below the partition wall 538 (that is, the partition displacement portion 573) is in contact with the third lead 22, and both are electrically connected. When the third lead 22 and the partition 538 are electrically connected, a current flows through the energization path between the negative electrode and the negative electrode terminal 12b.

  When the pressure in the case 4 rises and becomes equal to or greater than the current cutoff pressure value, the partition wall 538 bulges upward (FIG. 7). In this case, the partition 538 (specifically, the partition displacement portion 573 of the partition 538) and the third lead 22 are separated from each other, and the partition 538 and the third lead 22 are electrically insulated. Since the partition wall 538 and the third lead 22 are insulated, a current does not flow through the energization path between the negative electrode and the negative electrode terminal 12b.

  In the power storage device 2 of the present embodiment, as described above, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the partition wall displacement portion 573 moves upward. For this reason, the distance between the partition wall 538 and the magnet 80 is reduced. As a result, the attractive force with which the magnet 80 attracts the partition wall 538 is increased. This prevents the deformed partition wall 538 from returning to its original state. Accordingly, it is possible to prevent the power storage device 2 from being re-energized after the current interrupt device 340 has interrupted the power storage device 2.

  The correspondence between Example 4 and claims will be described. In this embodiment, the partition 538 and the third lead 22 are examples of “conductive member” in the claims, the partition 538 is an example of “first conductive portion” in the claims, and the third lead 22 is claimed. This is an example of “second conductive portion” in the section.

(Other form 1)
Hereinafter, another embodiment of the power storage device 2 disclosed in this specification will be described. The power storage device 2 of the first form is obtained by changing the current interrupt device 40 of the power storage device 2 of the first embodiment to a current interrupt device 202 (FIGS. 8 and 9). The current interrupt device 202 is disposed on the inner surface of the upper wall 4a of the case 4 in the same manner as the current interrupt device 40 of the first embodiment. In the power storage device 2 of this embodiment, similarly to the first embodiment, the negative electrode tab 55b (see FIG. 1), the current interrupt device 202, and the negative electrode terminal 12b (see FIG. 1) are connected in this order, so that the negative electrode and the negative electrode terminal are connected. An energization path that connects 12b is formed. When the pressure in the case 4 rises, the current interrupt device 202 interrupts this energization path (described in detail later).

  The current interrupting device 202 includes a deformable plate 603, an energizing plate 604, a contact plate 605, a lid 640, an insulating support member 611, and a caulking member 620. The deformation plate 603, the current supply plate 604, the contact plate 605, and the lid 640 are sequentially arranged from the lower side of FIG. 8 (inner side of the case 4) to the upper side of FIG. 8 (outside of the case 4). Has been.

  The deformation plate 603 is a thin plate diaphragm. The deformation plate 603 is made of a magnetic material. As a material for forming the deformation plate 603, for example, iron can be used. The outer peripheral portion of the deformation plate 603 is fixed by an insulating support member 611 described later. An insulating seal member 614 is disposed between the outer peripheral portion of the deformation plate 603 and the outer peripheral portion of the energization plate 604. Thereby, the outer peripheral part of the deformation | transformation board 603 and the outer peripheral part of the electricity supply board 604 are electrically insulated. A central portion of the deformation plate 603 is a pressure receiving portion 622. The lower surface of the pressure receiving portion 622 in FIG. 8 receives the pressure in the case 4. When the internal pressure in the case 4 rises above a predetermined level, the deformation plate 603 is deformed (described in detail later). A protrusion 612 that protrudes toward the contact plate 605 is provided on the upper surface of the central portion of the deformation plate 603. The protrusion 612 can have a cylindrical shape, for example. The protrusion 612 may be an insulator. The upper surface of the protrusion 612 is a contact portion 624. As shown in FIG. 8, the deformable plate 603 bulges inside the case 4 (lower side in FIG. 8) when the pressure in the case 4 is less than the current cutoff pressure value.

  The energization plate 604 is disposed on the upper side of the deformation plate 603. As shown in FIG. 8, the central portion of the energization plate 604 is thinner in the vertical direction than the outer peripheral portion of the energization plate 604. A fracture groove 616 is formed on the lower surface of the central portion of the energization plate 604. The fracture groove 616 is formed in an annular shape in plan view. The cross-sectional shape of the breaking groove 616 is a triangle. However, the sectional shape of the breaking groove 616 may be other shapes (for example, a semicircle). Moreover, the fracture | rupture groove | channel 616 is formed continuously. However, the breaking groove 616 may be formed discontinuously. The diameter of the fracture groove 616 is slightly larger than the diameter of the outer periphery of the contact portion 624 in plan view. The energization plate 604 includes a moving-side conductive portion 117 located inside the breaking groove 616 and a fixed-side conducting portion 116 located outside the breaking groove 616. A connection member 613 is provided on a part of the outer periphery of the current-carrying plate 604 (the end on the right side in FIG. 8). The connecting member 613 is electrically connected to the electrode assembly 6 at a position not shown (described in detail later).

  The contact plate 605 is disposed on the upper side of the energization plate 604. The contact plate 605 is a so-called diaphragm. Specifically, the contact plate 605 is a flat plate-shaped thin plate. The contact plate 605 is made of a conductive material. As a material for forming the contact plate 605, for example, metal (specifically, for example, aluminum) can be used.

  The outer peripheral portion of the contact plate 605 is fixed by an insulating support member 611 described later. The lower surface of the central portion 623 of the contact plate 605 is in contact with the upper surface of the energizing plate 604 described above. Specifically, the lower surface of the central portion 623 of the contact plate 605 and the upper surface of the moving-side conductive portion 117 are in contact with each other. Further, the lower surface of the central portion 623 of the contact plate 605 is also in contact with the upper surface of the fixed-side conductive portion 116 (specifically, the portion located around the fracture groove 616). Note that the lower surface of the central portion 623 of the contact plate 605 and the upper surface of the energizing plate 604 may be fixed by welding or the like. An insulating seal member 617 is provided between the outer periphery of the contact plate 605 and the outer periphery of the energization plate 604. The outer periphery of the contact plate 605 and the outer periphery of the energization plate 604 are electrically insulated from each other.

  The lid body 640 is disposed on the upper side of the contact plate 605. Moreover, the cover body 640 is arrange | positioned under the insulating sheet 34b. The lid 640 includes a main body portion 641 and a connection member 642 provided at the end portion of the main body portion 641 on the left side in FIG. The outer peripheral portion of the lid body 640 (specifically, the outer peripheral portion of the main body portion 641 of the lid body 640) is fixed by an insulating support member 611. The lower surface of the outer peripheral portion of the main body portion 641 and the upper surface of the outer peripheral portion of the contact plate 605 described above are electrically connected by being in contact with each other. A concave portion 618 that is recessed upward is formed on the lower surface of the main body portion 641. Thereby, when the pressure in case 4 rises and the contact plate 605 deform | transforms upwards, interference with the contact plate 605 and the cover body 640 is prevented. The connection member 642 is electrically connected to the negative electrode terminal 12b at a position not shown (described in detail later).

  An insulating support member 611 is disposed outside the outer peripheral portions of the deformation plate 603, the current supply plate 604, the contact plate 605, and the lid body 640. The support member 611 is formed by, for example, a resin mold. The support member 611 is formed in a ring shape. The inner surface of the support member 611 has a substantially U shape that opens toward the inside of the support member 611 in the cross-sectional shape. The outer periphery of the deformable plate 603, the seal member 614, the outer periphery of the energizing plate 604, the seal member 617, the outer periphery of the contact plate 605, and the outer periphery of the lid 640 are substantially U-shaped of the support member 611. Covered inside. Thereby, the deformation | transformation board 603, the sealing member 614, the electricity supply board 604, the sealing member 617, the contact plate 605, and the cover body 640 are integrally hold | maintained in the mutually laminated | stacked state. Since these components are integrally held in a state where they are stacked on each other, gas flow between the space in the case 4 and the space in the current interrupting device 602 is prevented. A metal caulking member 620 is disposed so as to cover the outer peripheral surface of the support member 611 and the upper and lower surfaces. The caulking member 620 holds the support member 611 in a state where it is sandwiched vertically. Thereby, the flow of gas between the space in the case 4 and the space in the current interrupting device 602 is further reliably prevented. An insulating sheet 34 b is disposed between the upper end portion of the current interrupt device 602 and the inner surface of the upper wall 4 a of the case 4.

  An energization path in the current interrupt device 202 of this embodiment will be described. Electrode assembly 6, connection member 613 of current plate 604, center portion of current plate 604, center portion 623 of contact plate 605, outer periphery of contact plate 605, outer periphery of lid 640, connection member 642 of lid 640, The negative electrode terminal 12b is electrically connected in order to form a series energization path.

  As shown in FIGS. 8 and 9, a magnet 80 is disposed inside the upper wall 4 a of the case 4. The magnet 80 is disposed above the deformation plate 603 in FIG. When viewed from above in FIG. 8, the magnet 80 is disposed at a position where the center of the magnet 80 and the center of the deformation plate 603 coincide. In other words, the magnet 80 is disposed at a position where the deformation plate 603 and the magnet 80 overlap when the deformation plate 603 is projected upward. The magnet 80 is disposed between the upper wall 4a of the case 4 and the above-described insulating sheet 34b.

  When the pressure in the case 4 rises and becomes equal to or higher than the current cutoff pressure value, the deformable plate 603 is deformed and the state shown in FIG. For this reason, the pressure receiving part 622 of the deformation plate 603 moves toward the upper side (outside of the case 4). As a result, the contact portion 624 of the protrusion 612 collides with the lower surface of the energizing plate 604 (specifically, the lower surface of the moving-side conductive portion 117 of the energizing plate 604). When the contact portion 624 collides with the lower surface of the energization plate 604, the energization plate 604 is broken at the portion of the breaking groove 616. When the breaking groove 616 breaks, the fixed-side conductive portion 116 and the moving-side conductive portion 117 of the energizing plate 604 are separated, and the moving-side conductive portion 117 moves upward. As described above, the moving-side conductive portion 117 is in contact with the central portion 623 of the contact plate 605. For this reason, the contact plate 605 is deformed. Thereby, the center part 623 of the contact plate 605 moves upward. As the center portion 623 of the contact plate 605 moves upward, the contact portion between the above-described center portion 623 of the contact plate 605 and the upper surface of the fixed-side conductive portion 116 (portion located around the breaking groove 616) is separated. To do. As a result, the energization path between the negative electrode terminal 12 b and the electrode assembly 6 is cut off, and no current flows between the negative electrode terminal 12 b and the electrode assembly 6.

  In the power storage device 2 of this embodiment, as described above, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the deformation plate 603 is deformed. For this reason, the pressure receiving part 622 of the deformation plate 603 moves upward. That is, the distance between the pressure receiving portion 622 of the deformation plate 603 and the magnet 80 is reduced. For this reason, the attractive force by which the magnet 80 attracts the pressure receiving portion 622 of the deformation plate 603 is increased. As a result, the state where the pressure receiving portion 622 moves upward is prevented from returning to the original state. Accordingly, it is possible to prevent the power storage device 2 from being re-energized after the current interrupt device 202 is disconnected from the power storage device 2.

  In the power storage device 2 of this embodiment, the deforming plate 603 blocks the contact portion between the energizing plate 604 and the contact plate 605 from the electrolyte atmosphere. Thereby, it can suppress that a contact part deteriorates with electrolyte solution or ambient environment. Even when the energization path is broken and an arc (spark) is generated, the influence on the case 4 in which hydrogen gas is generated can be suppressed.

  Further, in the power storage device 2 of this embodiment, the current interruption pressure is stabilized because the impact force of the protrusion 612 provided on the deformation plate 603 compensates for the variation in the breaking load of the breaking groove 616.

(Other form 2)
The power storage device 2 of the second form is obtained by changing the current interrupting device 202 of the power storage device 2 of the first form into a current interrupting device 302. Since the shape of the current interrupting device 302 is the same as that of the current interrupting device 202 (see FIGS. 8 and 9), the illustration is omitted. In the current interrupt device 202 of the first form, the deformation plate 603 is formed of a magnetic material. On the other hand, in the current interrupt device 302 of the second form, the contact plate 605 is made of a magnetic material.

  In the current interrupt device 302 of the second embodiment, as in the first embodiment, when the pressure in the case 4 becomes equal to or higher than the current interrupt pressure value, the energization path between the negative electrode and the negative electrode terminal 12b is interrupted. At this time, as in the first embodiment, the central portion 623 of the contact plate 605 moves upward. For this reason, the distance between the contact plate 605 and the magnet 80 is reduced. As a result, the attractive force with which the magnet 80 attracts the contact plate 605 is increased. As a result, the deformed contact plate 605 is prevented from returning. Thereby, it is possible to prevent the power storage device 2 from being re-energized after the current interrupt device 302 is disconnected from the power storage device 2.

  The correspondence relationship between the first and second embodiments and the claims will be described. The energization plate 604 and the contact plate 605 in the present embodiment are examples of the “conductive member” in the claims, and the moving-side conductive portion 117 and the contact plate 605 of the energization plate 604 are “first” in the claims. It is an example of a “conductive part”, and the fixed-side conductive part 116 of the energization plate 604 is an example of a “second conductive part” in the claims.

(Other form 3)
The power storage device 2 of the third embodiment is obtained by changing the current interrupt device 202 of the power storage device 2 of the first embodiment to a current interrupt device 402 (FIGS. 10 and 11). The current interrupt device 202 was provided with an energization plate 604. On the other hand, the current interrupt device 402 includes an energization plate 633. A through hole 634 is formed in the central portion 631 of the current supply plate 633. Similar to the first embodiment, the power storage device 2 of the third embodiment includes a contact plate 605. The contact plate 605 is disposed on the upper side of the energization plate 604. The central portion 631 of the current supply plate 633 (specifically, the portion around the through hole 634) and the central portion 623 of the contact plate 605 are in contact with each other and are electrically connected. The power storage device 2 according to the third embodiment includes the deformation plate 603 as in the first embodiment. The deformation plate 603 is made of a magnetic material. As a material for forming the deformation plate 603, for example, iron can be used.

  A protrusion 612 is provided on the upper side of the central portion of the deformation plate 603 (that is, on the upper side of the pressure receiving portion 622). When the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the deformation plate 603 is deformed, so that the pressure receiving portion 622 of the deformation plate 603 moves upward. As the pressure receiving portion 622 moves upward, the projection 612 penetrates the through hole 634 and the contact portion 624 of the projection 612 collides with the contact plate 605. For this reason, the contact plate 605 is deformed. Thereby, the center part 623 of the contact plate 605 moves upward. As a result, the central portion 623 of the contact plate 605 and the central portion 631 of the energizing plate 633 are separated. As a result, no current flows between the negative electrode terminal 12 b and the electrode assembly 6.

  Also in the power storage device 2 of the third form, as in the first form, when the pressure in the case 4 becomes equal to or higher than the current cutoff pressure value, the pressure receiving portion 622 of the deformation plate 603 moves upward. As a result, the attractive force with which the magnet 80 attracts the deformation plate 603 is increased. This prevents the deformed deformation plate 603 from returning to its original state. Accordingly, it is possible to prevent the power storage device 2 from being energized again after the current interrupting device 402 interrupts the power storage device 2.

  In the current interrupt device 402 of the third embodiment, the deformation plate 603 is made of a magnetic material. However, the contact plate 605 may be formed of a magnetic material as in the case of the current interrupt device 302 of the second embodiment.

  The correspondence between the third embodiment and the claims will be described. In the present embodiment, the energization plate 633 and the contact plate 605 are examples of the “conductive member” in the claims, and the contact plate 605 is an example of the “first conductive portion” in the claims, and the energization plate 633. Is an example of “second conductive portion” in the claims.

  In the first to third embodiments, the deformation plate 603 and the energization plate 633 are insulated while the protrusion 612 passes through the through hole 634. Here, the method of insulating the deformation plate 603 and the energization plate 633 may be to form the deformation plate 603 itself or the protrusion 612 on the deformation plate 603 with an insulating material. Further, the inner peripheral portion of the through hole 634 may be subjected to an insulating coating. Alternatively, in a state where the protrusion 612 passes through the through hole 634, the power storage device 2 is configured such that the protrusion 612 and the energization plate 633 are not in contact with each other and the deformation plate 603 and the energization plate 633 are not in contact with each other. It may be.

  In the above embodiment and other embodiments, the current interrupting device is arranged in the energization path that connects the negative electrode and the negative electrode terminal 12b. However, the current interrupting device may be disposed in an energization path that connects the positive electrode and the positive electrode terminal 12a.

  The partition walls 38 of Examples 1 to 3, the partition wall 538 of Example 4, and the contact plates 605 and deformation plates 603 of the other first to third forms were made of a magnetic material. However, in these configurations, it is only necessary that at least a part of these configurations is formed of a magnetic material. The part formed by the magnetic body may be at least a part of the part that is displaced when the pressure in the case 4 rises and these structures are deformed. These structures may be formed of an alloy of a magnetic material (for example, iron) and another material (for example, aluminum). Moreover, these structures may be formed by joining a magnetic body to the main body formed of the material (for example, aluminum) which is not a magnetic body. The magnetic body joined to the main body may also serve as the moving-side conductive portions 17 and 117 of the first embodiment, the other first form, and the other second form. The magnetic body joined to the main body may also serve as the projections 612 of other first to third forms.

The magnetic bodies forming the partition wall 38 of the first to third embodiments, the partition wall 538 of the fourth embodiment, the contact plate 605 and the deformation plate 603 of the first to third modes are shown in the above-described embodiments and other embodiments. It is not limited to iron (Fe). That is, the magnetic material is cobalt (Co), nickel (Ni), permalloy (Fe—Ni), FeCo alloy, or stainless steel (having a composition of Fe—Cr—C), Heusler alloy. (Cu ₂ MnAl) may also be used. In addition, the magnetic material includes an intermetallic compound samarium cobalt magnet (SmCo ₅ ), an inorganic neodymium magnet (Nd ₂ Fe ₁₄ B), an oxide magnetite (Fe ₃ O ₄ ), and a maghematite (γ-Fe _2). O ₃ ).

  In the above embodiments and other embodiments, the magnet 80 was a ferrite magnet. However, the magnet 80 may be another permanent magnet (for example, a neodymium magnet). The magnet 80 may be an electromagnet. Thereby, adjustment of the magnetic force of the magnet 80 can be facilitated. When the magnet 80 is an electromagnet, the power storage device 2 may include electrical wiring that supplies power from the electrode assembly 6 to the electromagnet.

  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 Power storage device 4 Case 4a Case upper wall 6 Electrode assembly 10a First lead 10b Second lead 14 Conductive member 16 Fixed side conductive portion 17 Moving side conductive portion 20 Fragile portion 22 Third lead 34b Insulating sheets 38 and 538 40, 202, 302, 340, 402 Current interrupter 72, 572 Outer peripheral edge 73, 573 Partition displacement part 80 Magnet

Claims (5)

Case and
An electrode assembly housed in the case;
An electrode terminal provided in the case;
A current interrupting device that is fixed to the case and interrupts an energization path between the electrode assembly and the electrode terminal;
The current interrupt device is
A partition wall that is deformed by receiving pressure in the case;
A conductive member that cuts off the energization path by being separated into a first conductive part and a second conductive part when the pressure in the case rises and the partition is deformed,
At least a part of the partition wall is formed of a magnetic material, or a magnetic material is bonded to at least a part of the partition wall;
The current interrupt device further includes a magnet that is fixed to the case and disposed on a side of the partition that deforms when the pressure in the case rises with respect to the partition.
Power storage device.   The power storage device according to claim 1, wherein the magnet is located at a position overlapping with the projected partition when the partition is projected in a direction in which the partition is deformed. The current interrupting device is fixed to the inner surface of the wall of the case;
The power storage device according to claim 1, wherein the magnet is located between a wall of the case and the partition wall.   The power storage device according to claim 1, wherein the magnetic body is iron. The power storage device according to any one of claims 1 to 4, wherein the power storage device is a secondary battery.

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