WO2015060175A1 - Electric storage device equipped with current shutoff device - Google Patents

Abstract

The current shutoff device of this first electric storage device is connected in series between a first electrode terminal provided on a terminal mount wall of a case and a first conductive member electrically connected to an electrode assembly housed inside the case, and connects or cuts off an energizing path from the electrode assembly to the first electrode terminal. The current shutoff device is disposed between the terminal mount wall and the electrode assembly. The electrode assembly has a wound structure, wherein a positive electrode sheet and a negative electrode sheet sandwiching a separator sheet are stacked in this state into a pair of electrodes in layer form and then wound. The first conductive member is connected to the electrode located on the current shutoff device side of the electrode assembly.

Description

Power storage device with current interrupt device

This application has priority based on Japanese Patent Application No. 2013-224502 filed on October 29, 2013 and Japanese Patent Application No. 2013-220012 filed on October 23, 2013. Insist. The entire contents of those applications are incorporated herein by reference. The present invention relates to a power storage device including a current interrupt device.

Japanese Patent Publication No. 2005-149862 describes a lithium battery equipped with a pressure detection type current interrupting device. In this battery, the current interrupting device is provided substantially below the positive electrode terminal (on the electrode assembly side). When the pressure in the battery case increases, the deforming plate of the current interrupting device is deformed, and the energization path between the positive electrode and the positive electrode terminal is interrupted. Japanese Patent Publication No. 2013-157200 describes a lithium battery including a pressure detection type current interrupting device. In this battery, the current interrupt device is provided substantially below the positive electrode terminal (on the electrode assembly side), and constitutes a current-carrying path between the positive electrode and the positive electrode terminal of the electrode assembly, and the pressure in the battery case is When it rises, the deformation plate of the current interrupt device is deformed, and the energization path between the positive electrode and the positive electrode terminal is interrupted. The reversing plate, the positive electrode current collecting plate and the like of the current interrupting device are made of aluminum.

っ て も Even if the pressure in the case is a low pressure within a normal range, the energization path of the power storage device may be interrupted. For example, if a current interrupt device is provided at a position on the electrode assembly side with respect to the electrode terminal, when the electrode assembly moves in the case, the current path on the side where the current interrupt device is installed is configured. May contact the member. As a result, when the positive electrode and the negative electrode are electrically connected, a short circuit may occur and the power storage device may fail. On the other hand, in Japanese Patent Publication No. 2005-149862, by arranging an insulating member on the electrode assembly side of the current interrupting device, the current interrupting device and the electrode assembly are brought into contact and short-circuited. prevent. In addition, for example, in a lithium-based power storage device, aluminum is generally used as the positive electrode current collector foil of the electrode assembly. As in Japanese Patent Publication No. 2013-157200, when a current interrupting device is installed in the current-carrying path on the positive electrode side, if the same aluminum as the current collector foil of the positive electrode is used as the material of the deformed plate, a creep phenomenon or the like may occur. The lower limit value of the pressure at which the deformed plate is deformed may decrease. In this case, even if the pressure in the case is a low pressure within a normal range, a malfunction that the current interrupting device interrupts the energization path may occur.

This specification provides a power storage device that can prevent a current-carrying path from being interrupted by operation other than normal operation of a current interrupting device.

A first power storage device disclosed in the present specification includes a case, an electrode assembly including a positive electrode and a negative electrode housed in the case, a first electrode terminal and a second electrode terminal provided on a terminal mounting wall of the case, The first conductive member housed in the case and connected to the electrode assembly, and both the polarity electrode and the second electrode terminal in the electrode assembly housed in the case and different from the side to which the first conductive member is connected The second conductive member connected to the first electrode member and the first conductive member housed in the case and connected in series to connect or cut off the energization path from the electrode assembly to the first electrode terminal. A current interrupting device. In this power storage device, the current interrupting device is disposed between the terminal mounting wall and the electrode assembly. The electrode assembly has a wound structure in which a sheet-like positive electrode and a sheet-like negative electrode are wound around a pair of electrodes stacked in a layered state with a sheet-like separator interposed therebetween. The first conductive member is connected to an electrode located on the current interrupt device side in the electrode assembly.

In the above first power storage device, the first conductive member is electrically connected to the electrode located on the current interrupting device side in the electrode assembly. The current interrupting device is connected in series between the first electrode terminal and the first conductive member, and connects or interrupts the energization path from the electrode assembly to the first electrode terminal. For this reason, even when the electrode assembly moves within the case, even if the current interrupting device and the first conductive member are in contact with the electrode located on the current interrupting device side in the electrode assembly, they are of the same polarity, Short circuit does not occur. Without using an insulating member, it is possible to more reliably prevent a short circuit due to contact between the member constituting the energization path on the side where the current interrupting device is installed and the electrode assembly.

In the first power storage device, the first electrode terminal is a negative electrode terminal, the first conductive member is connected to the negative electrode of the electrode assembly, and the electrode located on the current interrupting device side of the electrode assembly is: It may be a negative electrode.

In the first power storage device, the first electrode terminal and the second electrode terminal may be arranged along the direction of the winding axis of the electrode assembly.

In the first power storage device, a negative electrode may be disposed on the outermost side of the electrode assembly.

In the first power storage device, the current interrupting device is disposed at a position closer to the electrode assembly side than the first electrode terminal, and the end of the current interrupting device on the electrode assembly side is an electrode of the second electrode terminal. It may be closer to the electrode assembly than the end on the assembly side.

The second power storage device disclosed in this specification is a lithium-based power storage device. This power storage device includes a case, an electrode assembly including a positive electrode and a negative electrode housed in the case, a negative electrode terminal and a positive electrode terminal provided on a terminal mounting wall of the case, and a negative electrode of the electrode assembly housed in the case A first conductive member electrically connected to the electrode, a second conductive member housed in the case and electrically connected to the negative electrode terminal, and a positive electrode and a positive electrode terminal of the electrode assembly housed in the case Connected in series between the electrically connected third conductive member and the first conductive member and the second conductive member housed in the case to connect or cut off the energization path from the electrode assembly to the negative electrode terminal Current interrupting device. The current interrupt device includes a deformed plate that is electrically connected to the first conductive member and the second conductive member to form a part of the energization path. The deformable plate has a joining portion that joins the joined member that is either the first conductive member or the second conductive member and connects the energization path, and is deformed when the pressure in the case rises. The energization path is interrupted by separating from the joining member. The material of the deformable plate is a material that has at least one of creep characteristics and fatigue resistance higher than aluminum and does not alloy with lithium at the negative electrode potential.

In the second power storage device, the current interrupt device is connected in series between the first conductive member and the second conductive member to connect or interrupt the energization path from the electrode assembly to the negative electrode terminal. For this reason, the material of the deformed plate included in the current interrupting device should be selected from materials that do not alloy with lithium at the negative electrode potential and that have at least one of creep characteristics and fatigue resistance higher than that of aluminum. Can do. Thereby, since the durability of the deformable plate can be improved, it is possible to provide a power storage device including a current interrupting device excellent in durability.

In the second power storage device described above, the material of the deformation plate may be any one of copper, an alloy containing copper as a main component, nickel, and an alloy containing nickel as a main component.

In the second power storage device, the material of the deformable plate and the material of the member to be joined may be the same material.

In the second power storage device, the material of the deformation plate may be the same material as the material of the negative electrode terminal.

The first and second power storage devices may be secondary batteries.

According to the present invention, it is possible to provide a power storage device capable of preventing the energization path from being interrupted except by the normal operation of the current interrupting device.

1 is a longitudinal sectional view of a power storage device according to Embodiment 1. FIG. FIG. 2 is a sectional view taken along line II-II in FIG. 1 is a diagram conceptually showing an electrode assembly having a winding structure of a power storage device according to Example 1. FIG. It is a figure which shows the electric current interruption apparatus of FIG. 1 and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus of FIG. 1 and its vicinity, and has shown the state at the time of the overcharge of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 1, and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 1, and its vicinity, and has shown the state at the time of the overcharge of an electrical storage apparatus. 6 is a longitudinal sectional view of a power storage device according to Embodiment 2. FIG. FIG. 9 is a sectional view taken along line IX-IX in FIG. 8. It is a top view of the electrical storage apparatus seen from the XX line of FIG. It is a figure which shows the electric current interruption apparatus of FIG. 8 and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus of FIG. 8, and its vicinity, and has shown the state at the time of the overcharge of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 2, and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 2, and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 2, and its vicinity, and has shown the state at the time of the overcharge of an electrical storage apparatus. It is a figure which shows the electric current interruption apparatus which concerns on the modification of Example 2, and its vicinity, and has shown the state at the time of normal operation of an electrical storage apparatus.

The first power storage device disclosed in this specification can be used as a conventionally known power storage device such as a sealed secondary battery or a sealed capacitor. Furthermore, specific examples of the secondary battery include secondary batteries such as lithium ion batteries, nickel metal hydride batteries, nickel cadmium batteries, and lead storage batteries that are charged and discharged with a relatively high capacity and a large current. The second power storage device disclosed in this specification can be used for a conventionally known lithium-based power storage device such as a sealed secondary battery and a sealed capacitor. The first power storage device and the second power storage device may be mounted on a vehicle, an electric device, or the like.

A first power storage device disclosed in this specification is provided on a case, an electrode assembly, a first conductive member, a second conductive member, and a current interrupting device housed in the case, and a terminal mounting wall of the case. The first electrode terminal and the second electrode terminal are provided. The electrode assembly includes a positive electrode and a negative electrode. The first conductive member is connected to one electrode of the electrode assembly. The second conductive member is connected to both the electrode on the polarity side different from the side to which the first conductive member is connected and the second electrode terminal in the electrode assembly. The current interrupt device is connected in series between the first electrode terminal and the first conductive member. The current interrupting device is disposed between the terminal mounting wall and the electrode assembly.

The electrode assembly has a wound structure in which a sheet-like positive electrode and a sheet-like negative electrode are wound with a pair of electrodes stacked in layers with a sheet-like separator sandwiched therebetween. The electrode pair is wound around a predetermined axis. The electrode assembly may be immersed in the electrolyte.

The current interrupting device connects or interrupts the energization path from the electrode assembly to the first electrode terminal. For example, the electrode blocking device may constitute a part of a current-carrying path from the electrode assembly to the first electrode terminal. More specifically, for example, the energization path from the first electrode (positive electrode or negative electrode) corresponding to the first electrode terminal of the electrode assembly to the first electrode terminal is connected in series in this order. It may be electrically connected via a member or a current interrupt device.

The first conductive member is connected to an electrode located on the current interrupting device side in the electrode assembly. When the negative electrode is positioned closer to the current interruption device side of the electrode assembly than the positive electrode, the first conductive member is connected to the negative electrode, and the current interruption device is connected to the negative electrode side energization path (the negative electrode of the electrode assembly). To the first electrode terminal). When the positive electrode is positioned closer to the current interrupting device side in the electrode assembly than the negative electrode, the first conductive member is connected to the positive electrode, and the current interrupting device is connected to the current path on the positive electrode side (the positive electrode of the electrode assembly). To the first electrode terminal). Note that either the positive electrode or the negative electrode may be disposed on the outermost side of the electrode assembly, or a separator may be disposed. For example, the electrode assembly may be one in which the electrode pair is wound so that either one of the negative electrode and the positive electrode is outside and the other is inside, and the outermost outer periphery is directly used as an electrode. The outermost periphery may be covered with a member that does not constitute an electrode, such as a separator.

Although not limited, the first electrode terminal is a negative electrode terminal, the first conductive member is connected to the negative electrode of the electrode assembly, and the electrode positioned on the current interrupting device side of the electrode assembly is a negative electrode. preferable. In an electrode assembly, when winding an electrode pair in which a sheet-like positive electrode and a sheet-like negative electrode are stacked in a state where a sheet-like separator is sandwiched between them, the negative electrode side should be outside and the positive electrode side should be inside. I often turn. If the current interrupting device is designed so as to connect or interrupt the current path on the negative electrode side, it is possible to cope with the case where the electrode located on the current interrupting device side in the electrode assembly is the negative electrode.

The first electrode terminal and the second electrode terminal may be arranged along the direction of the winding axis of the electrode assembly. A space is easily formed between the electrode assembly and the terminal mounting wall in the case, and a short circuit that may occur when the electrode assembly moves toward the space can be effectively prevented.

The current interrupting device is disposed at a position closer to the electrode assembly side than the first electrode terminal, and the end of the current interrupting device on the electrode assembly side is more electrode than the end of the second electrode terminal on the electrode assembly side. It may be close to the assembly. Since the end of the current interrupting device is positioned closer to the electrode assembly, when the electrode assembly moves in the case, it is easier to contact the current interrupting device than the second electrode terminal. When the electrode assembly moves in the case, the members constituting the energization path on the side where the current interrupting device is preferentially contacted with the electrode assembly, and the electrode assembly and the second electrode terminal side It can suppress that the member which comprises an electricity supply path contacts.

A second power storage device disclosed in the present specification includes a case, an electrode assembly, a first conductive member, a second conductive member, a third conductive member, and a current interrupting device housed in the case, And an electrode terminal provided on the terminal mounting wall. The electrode assembly includes a positive electrode and a negative electrode. The first conductive member is electrically connected to the negative electrode of the electrode assembly, the second conductive member is electrically connected to the negative electrode terminal, and the current interrupt device includes a first conductive member and a second conductive member. They are connected in series. The third conductive member is electrically connected to the positive electrode and the positive electrode terminal of the electrode assembly.

In the second power storage device, as the electrode assembly, for example, an electrode assembly including a pair of electrode layers that are formed in a state where a sheet-like positive electrode and a sheet-like negative electrode sandwich a sheet-like separator therebetween. More specifically, a stacked electrode assembly in which a large number of electrode pairs are stacked, and a wound electrode assembly in which the electrode pairs are wound around a predetermined axis can be exemplified. . The electrode assembly may be immersed in the electrolyte.

In the second power storage device, on the negative electrode side, the current path from the negative electrode to the negative electrode terminal of the electrode assembly is connected in series in this order, the tab, the first conductive member, the current interrupting device, the second It is electrically connected via a conductive member. The current interrupting device of the second power storage device constitutes a part of the energization path from the negative electrode to the negative electrode terminal of the electrode assembly, and is configured to connect or interrupt the energization path.

In the second power storage device, the current interrupt device includes a deformation plate that is electrically connected to the first conductive member and the second conductive member to form a part of the energization path. The deformable plate has a joint portion that joins a member to be joined (either the first conductive member or the second conductive member) and connects the energization path. For example, the deformable plate is always electrically connected to one of the first conductive member and the second conductive member, and is electrically connected to the other by a joint portion, and appropriately interrupts energization at the joint portion. It may be possible. Further, either one of the first conductive member and the second conductive member may be formed integrally with the deformable plate, and the other may be joined as a member to be joined to the deformable plate at the joint. In the joining portion, it is preferable that the deformable plate and the member to be joined are fixed so as to be electrically connectable, for example, by welding or the like.

In the second power storage device, the deformable plate is deformed when the pressure in the case is increased, and is separated from the member to be joined, thereby interrupting the energization path. An example of the structure of the deformable plate is a diaphragm structure. The deformation plate may be a pressure-sensitive member that deforms when the pressure in the case increases and the pressure difference between the two surfaces of the deformation plate exceeds a predetermined value, or operates when the pressure in the case increases. It may be deformed by receiving a load applied by another pressure sensitive member. The pressure-sensitive member that applies a load to the deformation plate to be bonded to the member to be bonded may have the same structure as the deformation plate. An additional deformation plate for applying a load is not an essential component for the power storage device disclosed in the present application, and may not be electrically connected to the energization path.

In the second power storage device, when the pressure in the case rises and the deformable plate deforms, the deformable plate and the member to be joined may be separated from each other in the joint portion by, for example, welding of the joint portion peeling off, The deformable plate and the member to be joined may be separated in a state in which the joining at the joining portion is maintained, for example, by the member to be joined being broken around the joining portion. In the case of breaking the member to be joined, a configuration may be formed that facilitates breaking such as engraving on the member to be joined around the joint. When the member to be joined is broken to cut off the energization path, the breaking load can be easily adjusted, and the current interrupting device can be operated more accurately with respect to the desired pressure in the case.

In the second power storage device, the material of the deformable plate is a material that has at least one of creep characteristics and fatigue resistance higher than aluminum and does not alloy with lithium at the negative electrode potential. Specific examples of such materials include copper, an alloy containing copper as a main component, nickel, and an alloy containing nickel as a main component.

FIG. 1 is a cross-sectional view of the power storage device 100 according to the first embodiment. The power storage device 100 includes a case 1, a wound electrode assembly 60, a first conductive member 68, a second conductive member 64, a first electrode terminal 19, a second electrode terminal 119, and a current interrupt device. 120.

Case 1 is a substantially rectangular parallelepiped box-shaped member, and accommodates therein an electrode assembly 60, a first conductive member 68, a second conductive member 64, and a current interrupt device 120. The upper end surface of the case 1 is a terminal mounting wall, to which the first electrode terminal 19 and the second electrode terminal 119 are mounted. The first electrode terminal is electrically connected to the negative electrode of the electrode assembly 60, and the second electrode terminal 119 is electrically connected to the positive electrode of the electrode assembly 60.

As shown in FIGS. 2 and 3, the electrode assembly 60 includes a positive electrode sheet 601, a separator 603, a negative electrode sheet 602, and a separator 603 that are wound in this order with the positive electrode sheet 601 side facing inward. It has a wound structure wound around an axis (r-axis shown in FIGS. 1 and 3). The positive electrode sheet 601 includes an aluminum positive electrode metal foil 601a and a positive electrode active material layer 601b formed on both surfaces of the positive electrode metal foil 601a. The negative electrode sheet 602 includes a copper negative electrode metal foil 602a and negative electrode active material layers 602b formed on both surfaces of the negative electrode metal foil 602a. The separator 603 is an insulating porous body. The electrode assembly 60 is accommodated in the case 1 in a state impregnated with a liquid electrolyte. The r-axis that is the winding axis of the electrode assembly 60 is substantially parallel to the y-axis, and the first electrode terminal 19 and the second electrode terminal 119 are located at both ends of the terminal mounting wall along the r-axis direction. Each is arranged.

The first conductive member 68 includes a current collector 67, and the negative electrode sheet 602 of the electrode assembly 60 is bundled by the current collector 67. The second conductive member 64 includes a current collector 65, and the positive electrode sheet 601 of the electrode assembly 60 is bundled by the current collector 65.

As shown in FIG. 1, the first conductive member 68 has a shape obtained by bending a copper flat plate, extends below the first electrode terminal 19 in the negative direction of the y-axis, is bent, and is negative in the z-axis. It extends in the direction. The first conductive member 68 is connected to the negative electrode sheet 602 of the electrode assembly 60.

The current interrupting device 120 is connected to the first conductive member 68 on the lower surface side, and is connected to the first electrode terminal 19 on the upper surface side. Further, the first electrode terminal 19 and the first conductive member 68 are electrically connected via a current interrupt device 120. As described above, the current-carrying path on the negative electrode side from the negative electrode sheet 602 to the first electrode terminal 19 of the electrode assembly 60 passes through the first conductive member 68 and the current interrupting device 120 connected in series in this order. It is connected.

The second conductive member 64 has a shape obtained by bending a flat plate made of aluminum, extends below the second electrode terminal 119 in the positive direction of the y-axis, bends, and extends in the negative direction of the z-axis. The second conductive member 64 is connected to both the second electrode terminal 119 and the positive electrode sheet 601 of the electrode assembly 60. A current-carrying path on the positive electrode side from the positive electrode sheet 601 to the second electrode terminal 119 of the electrode assembly 60 is connected via a second conductive member 64. The current interrupting device 120 is disposed at a position closer to the electrode assembly 60 side with respect to the first electrode terminal 19, and the first electrode terminal 19 and the second electrode terminal 119 are disposed along the direction of the r-axis. Therefore, the lower end portion (the end portion on the electrode assembly 60 side) of the current interrupt device 120 is closer to the electrode assembly 60 than the lower end portion (the end portion on the electrode assembly 60 side) of the second electrode terminal 119. close. A portion extending in the y direction of the second conductive member 64 is attached above the lower end portion of the second electrode terminal 119. The power storage device 100 can exchange electricity between the electrode assembly 60 and the outside of the case 1 via the first electrode terminal 19 and the second electrode terminal 119.

As shown in FIG. 4, the current interrupt device 120 includes a deformation plate 33 and a contact plate 35. The deformation plate 33 is a copper diaphragm, and is a substantially flat plate-like member that is circular in a plan view, and has a truncated cone-shaped convex portion at the center. During normal operation of the power storage device 100, the convex portion of the deformation plate 33 is convex toward the side where the first conductive member 68 and the electrode assembly 60 are disposed (the negative direction side of the z axis). The contact plate 35 is a substantially flat plate-like member that is circular in a plan view, and has a flat plate-like central portion and a side portion that curves and extends from the central portion toward the deformable plate 33. The deformation plate 33 and the contact plate 35 are in contact with each other at the connection portion 34 and are fixed by welding. A wall that separates the space 40 from the electrode assembly 60 side in the case 1 is formed by the deformation plate 33 and the contact plate 35, and the upper surface (the surface on the positive side of the z axis) of the deformation plate 33 and the contact plate 35. The lower surface (the surface on the negative direction side of the z-axis) faces the space 40.

The deformation plate 33 and the contact plate 35 are made of copper like the first conductive member 68. The contact plate 35 is in contact with the first electrode terminal 19 and is fixed by welding. The deformation plate 33 is in contact with the first conductive member 68 and is welded to the first conductive member 68 at the joint portion 41. The first conductive member 68 has a circular hole 68a formed along the circular lower surface of the convex portion of the deformable plate 33, and the joint 41 is located around the hole 68a. . From the electrode assembly 60 toward the first electrode terminal 19, the first conductive member 68, the deformation plate 33, and the contact plate 35 are connected in series in this order.

Since the upper surface of the deformation plate 33 faces the space 40 and the lower surface faces the electrode assembly 60 side in the case 1, the pressure on the electrode assembly 60 side in the case 1 rises, and the case 1 side On the other hand, when the space 40 side has a negative pressure, the deformation plate 33 is reversed in a direction away from the first conductive member 68 as shown in FIG. As a result, the energization path on the negative electrode side is blocked.

Since the current interrupt device 120 is disposed between the terminal mounting wall and the electrode assembly 60, the current interrupt device 120 contacts the current interrupt device 120 or the first conductive member 68 when the electrode assembly 60 moves in the case. There is a case. In the power storage device 100, the first electrode terminal 19 is a negative electrode terminal, the first conductive member 68 is connected to the negative electrode sheet 602, and the current interrupt device 120 is connected to the first electrode terminal 19, the first conductive member 68, and the like. Are connected in series, and the energization path on the negative electrode side from the electrode assembly 60 to the first electrode terminal 19 is connected or cut off. In the electrode assembly 60, a pair of electrodes in which the positive electrode sheet 601, separator 603, negative electrode sheet 602, and separator 603 are stacked in this order are wound around the winding axis with the positive electrode sheet 601 side inside. The electrode which has a winding structure and is located on the current interrupting device 120 side is a negative electrode. For this reason, even if the electric current interruption apparatus 120 and the 1st electroconductive member 68 contact the negative electrode of the electrode assembly 60, it is the mutually same polarity and a short circuit does not occur. Without using an insulating member, it is possible to more reliably prevent the current interrupt device 120 or the first conductive member 68 and the electrode assembly 60 from contacting and short-circuiting.

Further, the end of the current interrupting device 120 on the electrode assembly 60 side is closer to the electrode assembly 60 than the end of the second electrode terminal 119 on the electrode assembly 60 side, and the deformation plate 33 of the current interrupting device 120 Since the lower surface is joined to the first conductive member 68, when the electrode assembly 60 moves in the case, the electrode assembly 60 is located at the first conductive member 68 rather than the lower end portion of the second electrode terminal 119. It is easier to come into contact with the lower surface. When the electrode assembly 60 moves within the case, the current interrupting device 120 or the first current constituting the energizing path (in this case, the energizing path on the negative electrode side) having the same polarity as the outer electrode (in this case, the negative electrode). The electrode assembly 60 comes into contact with the conductive member 68 and its movement is restricted, so that the electrode assembly 60 comes into contact with a member constituting the energization path on the side where the current interrupting device 120 is not installed (in this case, the positive-side energization path). It is suppressed. That is, according to the power storage device 100, it is possible to more reliably prevent a short circuit that may occur when the electrode assembly 60 moves without using an insulating member.

(Modification of Example 1)
In the above-described first embodiment, the case 1 is a substantially rectangular parallelepiped box-shaped member. However, the case may be a substantially cylindrical box-shaped member, for example.

In the first embodiment, the current interrupt device 120 has one surface of the deformation plate 33 having the joint portion 41 exposed to the pressure in the case 1, and the pressure in the case 1 rises, and this deformation occurs. Although it is reversed when the pressure difference between both surfaces of the plate 33 exceeds a predetermined value, it is not limited to this. For example, as in a current interrupting device 720 described below with reference to FIGS. 6 and 7, the pressure in the case 1 is increased in the first deformable plate 5 (an example of a deformed plate) joined to the first conductive member 68. The second deformation plate 3 (an example of a deformation plate) that is sometimes reversed may be deformed by receiving a load applied thereto, thereby interrupting the energization path. Further, the member to be joined (for example, the first conductive member) to be joined to the deformable plate may be cut while maintaining the joining without being divided by peeling when the current is interrupted. In the following description of the modification examples according to FIGS. 6 and 7, only portions different from the power storage device 100 of the first embodiment will be described, and redundant description of the same configuration as the power storage device 100 will be omitted.

The current interrupting device 720 includes the first deformable plate 5, the second deformable plate 3, insulating resin O- rings 14 and 17, support members 11 and 20, and protrusions 12. In the current interrupt device 720, the energization unit 4 provided at the end of the first conductive member 68 is inserted. The first deformation plate 5 is electrically connected to the first electrode terminal 19 through the sealing lid body 7. The first deformation plate 5, the energizing portion 4, and the second deformation plate 3 are arranged in this order in the direction from the first electrode terminal 19 side to the electrode assembly 60 side (the direction from the top to the bottom in FIG. 6). ing. An O-ring 17 is sandwiched between the first deformable plate 5 and the energizing portion 4, and an O-ring 14 is sandwiched between the energizing portion 4 and the second deformable plate 3. A space 740 is formed by the second deformation plate 3, the first deformation plate 5, the O- rings 14 and 17, and the support members 11 and 20.

The second deformable plate 3 is a diaphragm made of stainless steel, and is fixed to the outer peripheral portion by the support member 11 and is sealed from the electrode assembly 60 side in the case 1 by the O-ring 14. An insulating projection 12 is provided at the center of the second deformable plate 3 so as to project toward the energizing portion 4 side. The protrusion 12 has a cylindrical shape, and the surface on the current-carrying part 4 side is the contact part 24. The lower surface side of the second deformation plate 3 facing the surface on which the protrusions 12 are installed is a planar pressure receiving portion 22.

The central portion 15 of the energization portion 4 of the first conductive member 68 is formed thin. The central portion 15 is located above the contact portion of the protrusion 12 of the second deformable plate 3, and a fracture groove 16 is formed on the lower surface thereof. The upper surface of the central portion 15 is the joint portion 6. The energization part 4 is in contact with the first deformation plate 5 at the joint part 6.

The first deformation plate 5 is a copper diaphragm, and is fixed by a support member 11 at the outer peripheral portion. The first deformable plate 5 is in contact with the joint portion 6 of the energization portion 4 at the joint portion 23 on the lower surface of the central portion. The joining part 6 of the energizing part 4 and the joining part 23 of the first deformation plate 5 are fixed to each other by welding and are electrically connected.

An insulating sealing member 10 is mounted between the upper surface of the sealing lid 7 and the inner surface of the case 1 so that the sealing lid 7 and the case 1 are electrically insulated. The support member 11 is insulative, is formed by a resin mold, and is formed in a ring shape with a substantially U-shaped cross section. The outer surface of the second deformable plate 3, the O- rings 14 and 17, the outer periphery of the energization unit 4, and the outer periphery of the sealing lid 7 are covered with the substantially U-shaped inner surface of the support member 11 and these members are laminated. Are held together. The O- rings 14 and 17 and the support member 11 are insulative, the second deformable plate 3 and the energizing portion 4 are insulated, and the energized portion 4 of the first deformable plate 5 and the first conductive member 68 are joined. The parts other than the parts 6 and 23 are insulated. The outer surface of the support member 11 is covered with a metal caulking member 20 to ensure sealing and holding. Further, the inner surface portion of the sealing lid body 7 is a concave portion 18 that is recessed upward, and forms a space 740 when the first deformable plate 5 is deformed upward by the projections 12 of the second deformable plate 3.

From the electrode assembly 60 toward the first electrode terminal 19, the energization part 4, the first deformation plate 5, and the sealing lid 7 of the first conductive member 68 are connected in series in this order. The first electrode terminal 19 and the first conductive member 68 are electrically connected via the first deformation plate 5 of the current interrupt device 720. During normal operation of the power storage device, the contact portion 24 of the protrusion 12 is not in contact with the energization portion 4 as shown in FIG. That is, the energization path on the negative electrode side is connected.

When the power storage device is overcharged, as shown in FIG. 7, the second deformable plate 3 is deformed toward the energizing portion 4, and the abutting portion 24 of the protrusion 12 abuts on the lower surface of the central portion of the energizing portion 4 to energize. The portion 4 is broken at the breaking groove 16, and the central portion of the energization portion 4 is separated from the energization portion 4. As a result, the joining portion 6 and the joining portion 23 are separated from and separated from the energizing portion 4, the electrical connection between the current interrupting device 720 and the first conductive member 68 is interrupted, and the energizing path on the negative electrode side is interrupted. Is done.

In the first embodiment and the modification thereof, the current interrupting device is disposed on the current path on the negative electrode side. However, when the electrode located on the current interrupting device side in the electrode assembly is a positive electrode, The interruption device is disposed on the positive electrode energization path.

FIG. 8 is a cross-sectional view of the lithium-based power storage device 202 according to the second embodiment. The power storage device 202 includes a case 204, an electrode assembly 206, a first conductive member 210a, a second conductive member 222, a third conductive member 210b, a negative electrode terminal 212a, a positive electrode terminal 212b, and an insulating member. 234a, 234b and a current interrupt device 440 are provided.

The electrode assembly 206 includes a sheet-like negative electrode, a sheet-like positive electrode, and a sheet-like separator that is sandwiched between and separated from the negative electrode and the positive electrode. The negative electrode includes a negative electrode active material and a negative electrode metal foil. Examples of the negative electrode active material include materials that can be stored and released in known lithium-based power storage devices (for example, carbon such as graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, and soft carbon, lithium, and sodium) Alkali metals such as, metal compounds, metal oxides such as SiOx, and boron-added carbon. The positive electrode includes a positive electrode active material and a positive electrode metal foil. Examples of the positive electrode active material include materials used in conventionally known lithium-based power storage devices (for example, LiNiO ₂ , LiCoO ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.8 Co _0.15 A composite oxide of lithium and manganese, nickel, cobalt, aluminum, or the like, such as Al _0.05 O ₂ , Li ₂ MnO ₂ , LiMn ₂ O ₄ , or LiNi _0.5 Mn _0.5 O _2. Can do. The electrode assembly 206 is a laminate in which negative electrodes and positive electrodes are alternately laminated in layers with a separator interposed therebetween, and is impregnated with a liquid electrolyte. A tab 208a extends from the negative electrode metal foil of the electrode assembly 206, and a tab 208b extends from the positive electrode metal foil. The negative electrode metal foil is a copper foil, and the positive electrode metal foil is an aluminum foil.

The case 204 is a substantially rectangular parallelepiped box-shaped member, and includes an electrode assembly 206 (including tabs 208a and 208b), a first conductive member 210a, a second conductive member 222, and a third conductive member 210b. The current interrupting device 440 and the insulating members 234a and 234b are accommodated. A negative electrode terminal 212 a and a positive electrode terminal 212 b are provided on the terminal mounting wall 204 a (the wall in the positive z-axis direction) of the case 204. The negative electrode terminal 212a and the positive electrode terminal 212b are provided at both ends of the terminal mounting wall 204a in the x direction, and the tabs 208a and 208b are provided at the center of the electrode assembly 206 in the x direction. Tabs 208a protruding from one end of the plurality of negative electrode metal foils of the electrode assembly 206 are bundled, and similarly tabs 208b protruding from one end of the plurality of positive electrode metal foils are bundled. The electrode assembly 206 is covered with an insulating film, and protrudes from the insulating film at portions connected to the tabs 208a and 208b.

As shown in FIG. 9, the tab 208 a extends from the electrode assembly 206 toward the terminal mounting wall 204 a of the case 204 in the positive direction of the z-axis and bends in the negative direction of the y-axis in the middle. It is formed in a shape having a flat portion 218a substantially parallel to the mounting wall 204a. Similarly, the tab 208b extends in the positive direction of the z-axis from the electrode assembly 206 toward the terminal mounting wall 204a of the case 204, and bends in the negative direction of the y-axis in the middle, to the terminal mounting wall 204a of the case 204. It is formed in a shape having a substantially parallel flat portion 218b.

As shown in FIG. 8, the first conductive member 210a and the second conductive member 222 are flat conductive members made of copper. The first conductive member 210 a extends linearly in the x direction substantially parallel to the terminal mounting wall 204 a of the case 204. The second conductive member 222 is disposed farther from the terminal mounting wall 204a of the case 204 than the first conductive member 210a in the z direction, and is straight in the x direction substantially parallel to the terminal mounting wall 204a of the case 204. It extends to the shape. As shown in FIG. 9, the lower surface (surface on the electrode assembly 206 side) of the first conductive member 210a and the upper surface (surface on the terminal mounting wall 204a side) of the flat portion 218a of the tab 208a are in contact with each other. It is fixed by welding.

As shown in FIG. 8, the third conductive member 210b is a flat conductive member made of aluminum. The third conductive member 210b extends linearly in the x direction substantially parallel to the terminal mounting wall 204a of the case 204. The lower surface of the third conductive member 210b is in contact with the upper surface of the flat portion 218b of the tab 208b, and both are fixed by welding.

The negative electrode terminal 212a includes a bolt 224a, an inner nut 226a, and an outer nut 228a. The bolt 224a, the inner nut 226a, and the outer nut 228a are made of copper. At the position where the negative electrode terminal 212a is disposed, a through hole is formed in the terminal mounting wall 204a of the case 204, and an insulating gasket 230a is attached to the through hole. The inner nut 226a passes through a through hole formed in the second conductive member 222 and is attached to the gasket 230a. The bolt 224a is fastened to the inner nut 226a via the seal washer 232a. The second conductive member 222 is sandwiched between the inner nut 226a and the gasket 230a. The gasket 230a is integrally formed with a flat insulating member 234a that extends in parallel with the inner surface of the terminal mounting wall 204a while contacting the inner surface of the terminal mounting wall 204a of the case 204. The upper surface of the first conductive member 210a and the upper surface of the second conductive member 222 are in contact with the insulating member 234a. The outer nut 228a of the negative electrode terminal 212a is used to connect the negative electrode terminal 212a and the wiring member.

The positive electrode terminal 212b includes a bolt 224b, an inner nut 226b, and an outer nut 228b. The bolt 224b, the inner nut 226b, and the outer nut 228b are made of aluminum. A through hole is formed in the terminal mounting wall 204a of the case 204 at a position where the positive electrode terminal 212b is disposed, and an insulating gasket 230b is attached to the through hole. The inner nut 226b passes through a through hole formed in the third conductive member 210b and is attached to the gasket 230b. The bolt 224b is fastened to the inner nut 226b via the seal washer 232b. The third conductive member 210b is sandwiched between the inner nut 226b and the gasket 230b. The gasket 230b is formed integrally with a flat plate-like insulating member 234b that extends in parallel with the inner surface of the terminal mounting wall 204a while contacting the inner surface of the terminal mounting wall 204a of the case 204. The upper surface of the third conductive member 210b is in contact with the insulating member 234b. The outer nut 228b of the positive electrode terminal 212b is used for connecting the positive electrode terminal 212b and the wiring member.

As shown in FIG. 8, the first conductive member 210 a and the second conductive member 222 are connected via a current interrupt device 440. The first conductive member 210a and the current interrupting device 440 are connected to each other at the connecting portion 440a, and the second conductive member 222 and the current interrupting device 440 are connected to each other at the connecting portion 440b that is farther from the terminal mounting wall 204a than the connecting portion 440a. It is connected. The energization path on the negative electrode side from the negative electrode to the negative electrode terminal 212a is connected by the tab 208a, the first conductive member 210a, the current interrupting device 440, and the second conductive member 222 connected in series in this order. As shown in FIG. 10, the negative electrode terminal 212a, the current interrupting device 440, the tabs 208a and 208b, and the positive electrode terminal 212b are arranged to overlap in the x direction in which the first conductive member 210a extends. .

As shown in FIG. 11, the current interrupt device 440 includes an insulation that mechanically fixes the negative end portion of the first conductive member 210 a in the x-axis direction and the positive end portion of the second conductive member 222 in the x-axis direction. And a reversing plate 438 as a conductive deformation plate held by the bracket 436 in contact with the second conductive member 222. The inversion plate 438 is a diaphragm made of copper. When the pressure in the case 204 is smaller than the predetermined value, it is in a state of bulging in the negative direction of the z-axis as shown in FIG. 11, and when the pressure in the case 204 becomes equal to or higher than the predetermined value, as shown in FIG. It will be in the state of bulging in the positive direction of the shaft. In the state where the reversing plate 438 bulges in the negative z-axis direction as shown in FIG. 11, the portion 438 a bulging in the negative z-axis direction of the reversing plate 438 is the edge of the opening 222 a formed in the second conductive member 222. And are fixed by welding by the joint portion 433. The first conductive member 210a and the second conductive member 222 are electrically connected through the reversing plate 438. When the reversal plate 438 bulges in the positive direction of the z-axis as shown in FIG. 12, the joint portion 433 is peeled off and the reversal plate 438 is separated from the second conductive member 222, and the first conductive member 210a and the second conductive member The conductive member 222 is electrically insulated. The second conductive member 222 has an opening 222a so as not to interfere with the bulged portion 438a of the reversing plate 438 when the reversing plate 438 is swollen in the negative z-axis direction. Yes. The lower surface of the bulged portion 438 a of the reversing plate 438 is exposed to the pressure on the electrode assembly 206 side of the case 204. When the pressure in the case 204 becomes a predetermined value or more, the pressure difference received between the lower surface and the upper surface of the bulged portion 438a of the reversing plate 438 becomes larger than the predetermined value, and the reversing plate 438 is reversed. As a result, the joint portion 433 is peeled off, the reversal plate 438 is separated from the second conductive member 222, and the energization path is interrupted.

As described above, according to the power storage device 202, the current interrupt device 440 is connected in series between the first conductive member 210a and the second conductive member 222, and the negative electrode side tab 208a of the electrode assembly 206 is connected to the negative electrode. Since it arrange | positions so that the electricity supply path | route to the electrode terminal 212a may be connected or interrupted | blocked, copper with a creep characteristic and fatigue resistance higher than aluminum can be used as a material of the inversion board 438 (an example of a deformation | transformation board). For this reason, the reversal plate 438 is deteriorated, and the pressure in the case 204 is deformed in a state lower than the design, so that a malfunction that blocks the energization path is less likely to occur. In other words, according to the power storage device 202, the durability of the reversing plate 438 can be improved, and as a result, the durability of the current interrupt device 440 can be improved.

The material of the reversal plate 438 has been described by taking copper as an example, but is not limited thereto, and at least one of creep characteristics and fatigue resistance is selected from materials that are not alloyed with lithium at the negative electrode potential. If a material higher than aluminum is selected and used, the effect of improving the durability of the reversing plate 438 and the durability of the current interrupting device 440 as described above can be obtained. Examples of materials that can be suitably used as the material of the reversing plate 438 include copper, an alloy containing copper as a main component, nickel, an alloy containing nickel as a main component, and the like. Copper and nickel are known as metals having superior creep characteristics, higher strength and rigidity, and higher fatigue resistance than aluminum.

Also, the material of the reversing plate 438 and the material of the second conductive member 222 joined to the reversing plate 438 are both copper and the same material. For this reason, the inversion board 438 and the 2nd electrically-conductive member 22 can be connected easily and reliably by welding.

Also, the material of the reversing plate 438 and the material of the negative electrode terminal 212a are both copper and the same material. For this reason, the electrical resistance of the energization path on the negative electrode side can be reduced.

Further, according to the power storage device 202, the first conductive member 210a extends in the x direction along the terminal mounting wall 204a at a position closer to the terminal mounting wall 204a than the second conductive member 222 in the z direction. The tab 208a and the current interrupting device 440 are connected by the connecting portion 440a closer to the terminal mounting wall 204a than the second conductive member 222 in the z direction. Further, the second conductive member 222 extends in the x direction along the terminal mounting wall 204a at a position farther from the terminal mounting wall 204a than the first conductive member 210a in the z direction, and more than the connecting portion 440a in the z direction. The current interrupting device 440 and the negative electrode terminal 212a are connected by a connecting portion 440b far from the terminal mounting wall 204a. Therefore, the current interrupting device 440 can be installed using the space generated between the terminal mounting wall 204a and the electrode assembly 206 by the tab 208a protruding toward the terminal mounting wall 204a. Can be miniaturized. Furthermore, the space for largely bending the first conductive member 210a and the second conductive member 222 can be omitted, which can contribute to the miniaturization of the power storage device 202. In addition, since the first conductive member 210a and the second conductive member 222 can be made smaller than in the case of being largely bent, the power storage device 202 can be reduced in cost. Further, since it is not necessary to provide a portion protruding outside the terminal mounting wall 204a in order to accommodate the current interrupt device, the degree of freedom in connecting the negative electrode terminal 212a and the positive electrode terminal 212b to the wiring is improved.

The tabs 208a and 208b and the current interrupt device 440 are at least partially overlapped in the x direction in which the first conductive member 210a extends. For this reason, the dead space in case 204 can be made smaller and the dimension of the power storage device 202 in the z direction can be reduced.

The first conductive member 210a and the second conductive member 222 extend in a straight line parallel to the terminal mounting wall 204a. For this reason, the 1st conductive member 210a and the 2nd conductive member 222 are easy to process, it is excellent in cost performance, and can make processing accuracy high.

Further, the power storage device 202 is provided with plate-like insulating members 234a and 234b that are in contact with the inner wall of the terminal mounting wall 204a of the case 204 in parallel. Therefore, the current interrupting device 440 and the tabs 208a and 208b are placed as close as possible to the terminal mounting wall 204a of the case 204 while ensuring insulation from the case 204, and the terminal mounting wall 204a of the case 204 and the electrode assembly 206 are The distance between them can be shortened, and the power storage device 202 can be reduced in size. Furthermore, since the first conductive member 210a is disposed in contact with the plate-like insulating member 234a, the current interrupt device 440 and the tab 208a can be prevented from vibrating with respect to the case 204.

Further, the tabs 208a and 208b are bent in the y direction substantially parallel to the terminal mounting wall 204a, and flat portions 218a and 218b substantially parallel to the terminal mounting wall 204a are formed. With such a configuration, the vertical dimension (z direction) of the power storage device 202 can be reduced as compared with the case where the tabs 208a and 208b are straightened.

Further, the negative electrode terminal 212a, the current interrupt device 440, and the tab 208a are arranged offset from each other when viewed from the terminal mounting wall 204a of the case 204, and the negative electrode terminal 212a, the current interrupt device 440 and the tab 208a overlap with each other in the x direction in which the first conductive member 210a extends. Further, in the power storage device 202 of the present embodiment, the upper end portion of the tab 208 a is disposed at a position closer to the terminal mounting wall 204 a of the case 204 than the lower end portion of the current interrupt device 440. With such a configuration, the space on the side of the negative electrode terminal 212a and the side of the current interrupting device 440, which have conventionally been a dead space, is effectively used, and the vertical dimension of the power storage device 202 is reduced. Can be

(Modification of Example 2)
In the second embodiment, the case is described where the case is a substantially rectangular parallelepiped box-shaped member. However, the case may be a substantially cylindrical box-shaped member, for example.

In the second embodiment, the case where the first conductive member 210a is sandwiched between the flat portion 218a of the tab 208a and the insulating member 234a has been described, but other configurations may be employed. For example, the flat portion 218a may be brought into contact with the insulating member 234a, and the first conductive member 210a may be brought into contact with the lower side of the flat portion 218a. Alternatively, the flat portion 218a may be brought into contact with the insulating member 234a, and the first conductive member 210a may be inserted into the flat portion 218a. The same applies to the relationship between the tab 208b, the third conductive member 210b, and the insulating member 234b.

Further, instead of the current interrupt device 440, a current interrupt device 240 as shown in FIG. 13 may be used. The current interrupting device 240 is different from the current interrupting device 440 in that the protective plate 470 is provided, and the other configuration is the same as that of the current interrupting device 440. Omitted. As shown in FIG. 13, in the current interrupt device 240, an insulating protective plate 470 is provided below the reversing plate 438. The protection plate 470 is fixed to the lower surface of the insulating bracket. The protective plate 470 is disposed between the reversing plate 438 and the electrode assembly 206 (see FIG. 1). Therefore, even if the electrode assembly 206 contacts the current interrupt device 240, it is possible to prevent the reverse plate 438 from malfunctioning. When the internal pressure of the case 204 is less than a predetermined level (for example, when the internal pressure of the case 204 is normal), it is possible to prevent the energization path between the electrode assembly 206 and the positive electrode terminal 212b from being interrupted. Further, since the protective plate 470 is insulative, it is possible to prevent the reversal plate 438 and the electrode assembly 206 from coming into contact with each other and short-circuiting. The protective plate 470 is provided with a through hole 472. Therefore, when the internal pressure of the case 204 rises above a predetermined level, the pressure is not prevented from being applied to the portion 438a of the reversing plate 438.

Moreover, in said Example 2 and its modification, as for the electric current interruption apparatuses 440 and 240, one surface of the inversion board which has a junction part is exposed to the pressure in a case, the pressure in a case rises, The reversal is reversed when the pressure difference between both surfaces of the reversal plate is equal to or greater than a predetermined value. However, the present invention is not limited to this. For example, like the current interrupting device 340 described below with reference to FIGS. 14 and 15, the first reversing plate 330 (an example of a deforming plate) having the joint portion 333 is reversed when the pressure in the case increases. You may reverse in response to the load which the 2nd inversion board 342 (an example of a deformation | transformation board) applies. Further, the member to be joined (the first conductive member or the second conductive member) joined to the reversing plate at the joining portion may not be broken when the current is interrupted, and may be peeled off from the reversing plate. 14 and 15 described below, only portions different from the power storage device 202 of the second embodiment will be described, and redundant description of the same configuration as the power storage device 202 will be omitted.

As shown in FIG. 14, the current interrupting device 340 includes a first reversing plate 330, a second reversing plate 342, support members 360 and 370, and an O-ring 371. The current interrupting device 340 includes an inner portion 350 that is an end of the first conductive member 210a on the negative electrode terminal 212a side (the negative direction of the x-axis shown in FIG. 8), and a tab 208a side of the second conductive member 222 ( An inner portion 320 that is an end portion in the positive direction of the x-axis shown in FIG. 8 is inserted. An inner portion 350, a first reversing plate 330, an inner portion 320, and a second reversing plate 342 are arranged in this order in the direction from the negative electrode terminal 212a toward the electrode assembly 206 (the negative direction of the z-axis). Yes. The first reversing plate 330 is housed in the current interrupt device 340, and the lower surface (the surface on the negative side of the z axis) of the second reversing plate 342 is exposed to the pressure on the electrode assembly 206 side of the case 204. Has been. An O-ring 371 is sandwiched between the first reversing plate 330 and the inner portion 320.

The support member 360 and the terminal mounting wall 204a of the case 204 are electrically insulated by an insulating member 234a. The support member 370 is insulative, molded with a resin mold, and formed in a ring shape with a substantially U-shaped cross section. The substantially U-shaped inner surface of the support member 370 covers the outer peripheral portions of the first reversing plate 330 and the second reversing plate 342, the outer peripheral portions of the O-ring 371 and the inner peripheral portions 320 and 350, and covers these members. They are sandwiched and held together. The support member 360 is a caulking member made of stainless steel, and covers the outer surface of the support member 370 to ensure sealing and holding.

The first reversing plate 330 and the second reversing plate 342 are made of a thin plate, for example, a diaphragm made of copper. The first reversing plate 330 and the second reversing plate 342 are fixed on the outer peripheral portion by the support member 370 and sealed to the electrode assembly 6 side in the case 204. ing. The first reversing plate 330 and the second reversing plate 342 have center portions 330a and 342a and peripheral portions 330b and 342b, respectively. The central portions 330a and 342a are disk-shaped substantially perpendicular to the z-axis, and the peripheral portions 330b and 342b are curved shapes surrounding the central portions 330a and 342a. A convex portion 343 that protrudes toward the inner portion 320 side is provided at the central portion 342 a of the second reversing plate 342. The convex portion 343 has a cylindrical shape, and the surface on the inner portion 320 side of the convex portion 343 is covered with an insulating member 344.

The inner portion 320 and the inner portion 350 have center portions 320a and 350a and peripheral portions 320b and 350b, respectively. The central portions 320a and 350a are formed thin, and the peripheral portions 320b and 350b are gradually thinner toward the central portions 320a and 350a, respectively. As described above, the inner portion 320 and the inner portion 350 as a whole have a recessed portion that is recessed upward, and forms a space for the first reversing plate 330 and the second reversing plate 342 to be reversed.

The first reversing plate 330 is joined to and electrically connected to the inner portion 350 at the outer edge of the peripheral portion 330b, and joined to the inner portion 320 at the joint portion 333 of the central portion 330a, and is fixed by welding. The outer edge of the peripheral portion 330b and the inner portion 320 are insulated by an O-ring 371. The first reversing plate 330 and the inner portion 320 are electrically connected only at the joint 333. Inside the current interrupting device 340, the negative-side energization path is connected by an inner portion 350, a first reversing plate 330, and an inner portion 320 that are connected in series in this order. In addition, although the 2nd inversion board 342 is joined and electrically connected with the inner part 320 in the outer edge of the peripheral part 342b, these do not need to be electrically connected.

The joint part 333 is located above the convex part 343 of the second reversing plate 342, and a marking part 322 is formed on the lower surface of the central part 320a located below the periphery of the joint part 333. The central portion 320a is thin in the stamped portion 322 so as to be easily broken.

When the pressure in the case 204 rises, the upper surface side of the second reversing plate 342 becomes a negative pressure with respect to the lower surface side. When the pressure difference between the upper surface side and the lower surface side of the second reversing plate 342 becomes a predetermined value or more, as shown in FIG. 15, the second reversing plate 342 is reversed in the z direction, and the convex portion 343 moves toward the central portion 320a. Moving. The convex portion 343 contacts the lower surface of the central portion 320a through the insulating member 344 and applies a load. As a result, the central portion 320 a is broken in the marking portion 322, the portion joined to the joint portion 333 is separated from the inner portion 320, and the first reversing plate 330 is reversed and separated from the inner portion 320. In the normal operation of the power storage device 202 shown in FIG. 14, the first reversing plate 330 and the inner portion 320 are electrically connected only at the joint portion 333, so the portion joined to the joint portion 333 as shown in FIG. 15. Is separated from the inner portion 320 and the first reversing plate 330 is separated from the inner portion 320, whereby the energization of the first reversing plate 330 and the inner portion 320 is interrupted. As a result, the electrical connection between the first conductive member 210a and the second conductive member 222 is interrupted, and the energization path on the negative electrode side is interrupted.

Further, instead of the current interrupt devices 440, 240, and 340, a current interrupt device 540 as shown in FIG. 16 may be used. The current interrupting device 540 is different from the current interrupting device 340 in that the protective plate 570 is provided, and the other configuration is the same as that of the current interrupting device 340. Omitted. As shown in FIG. 16, in the current interrupt device 540, an insulating protective plate 580 is provided below the second reversing plate 342. The protection plate 580 is supported by the support members 360 and 370 together with the outer periphery of the first reversing plate 330 and the second reversing plate 342, the O-ring 371 and the inner portions 320 and 350. The protection plate 580 is disposed between the second reverse plate 342 and the electrode assembly 206 (see FIG. 8). Therefore, even if the electrode assembly 206 contacts the current interrupt device 540, it is possible to prevent the second reversing plate 342 from malfunctioning. When the internal pressure of the case 204 is less than a predetermined level, it is possible to prevent the energization path between the electrode assembly 206 and the positive electrode terminal 212b from being interrupted. Further, since the protective plate 580 is insulative, it is possible to prevent the second reversal plate 342 and the electrode assembly 206 from coming into contact with each other and short-circuiting. The protective plate 580 is provided with a through hole 582. Therefore, when the internal pressure of the case 204 rises above a predetermined level, the pressure is not prevented from being applied to the convex portion 343 of the second reverse plate 342.

In the above embodiment, the current interrupting devices 440, 240, 340, and 540 are embodied as reversing plates by reversing plates that reverse when the pressure in the case rises, but are not limited thereto. Any deformable plate may be used as long as the pressure in the case rises and deforms in response to the pressure and blocks the energization path.

As mentioned above, although embodiment and the Example of this invention were described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

Claims (10)

1. Case and
   An electrode assembly housed in the case and comprising a positive electrode and a negative electrode;
   A first electrode terminal and a second electrode terminal provided on a terminal mounting wall of the case;
   A first conductive member housed in the case and connected to the electrode assembly;
   A second conductive member connected to both the second electrode terminal and the polarity side different from the side to which the first conductive member is connected in the electrode assembly housed in the case;
   A current interrupting device that is accommodated in the case and connected in series between the first electrode terminal and the first conductive member, and that connects or blocks an energization path from the electrode assembly to the first electrode terminal; A power storage device comprising:
   The current interrupting device is disposed between the terminal mounting wall and the electrode assembly;
   The electrode assembly has a wound structure in which a sheet-like positive electrode and a sheet-like negative electrode are wound around a pair of electrodes stacked in a state where a sheet-like separator is sandwiched therebetween,
   The first conductive member is connected to an electrode located on the current interrupting device side in the electrode assembly.
   Power storage device.
2. The first electrode terminal is a negative electrode terminal;
   The first conductive member is connected to a negative electrode of the electrode assembly;
   The power storage device according to claim 1, wherein the electrode located on the current interrupt device side of the electrode assembly is a negative electrode.
3. The power storage device according to claim 1 or 2, wherein the first electrode terminal and the second electrode terminal are arranged along a winding axis direction of the electrode assembly.
4. The power storage device according to claim 2, wherein a negative electrode is disposed on the outermost side of the electrode assembly.
5. The current interrupting device is disposed at a position closer to the electrode assembly side than the first electrode terminal,
   The end portion on the electrode assembly side of the current interrupt device is closer to the electrode assembly than the end portion on the electrode assembly side of the second electrode terminal, according to any one of claims 1 to 4. Power storage device.
6. Case and
   An electrode assembly housed in the case and comprising a positive electrode and a negative electrode;
   A negative electrode terminal and a positive electrode terminal provided on the terminal mounting wall of the case;
   A first conductive member housed in the case and electrically connected to the negative electrode of the electrode assembly;
   A second conductive member housed in the case and electrically connected to the negative electrode terminal;
   A third conductive member housed in the case and electrically connected to the positive electrode of the electrode assembly and the positive electrode terminal;
   A current interrupting device that is accommodated in the case and connected in series between the first conductive member and the second conductive member, and connects or interrupts an energization path from the electrode assembly to the negative electrode terminal; Prepared,
   The current interrupting device includes a deformation plate that is electrically connected to the first conductive member and the second conductive member to form a part of the energization path,
   The deformable plate has a joint portion that joins the member to be joined, which is either the first conductive member or the second conductive member, and connects the energization path, and when the pressure in the case rises To be separated from the member to be joined and cut off the energization path,
   The material of the deformable plate is a lithium power storage device in which at least one of creep characteristics and fatigue resistance is higher than aluminum and does not alloy with lithium at the negative electrode potential.
7. The power storage device according to claim 6, wherein the material of the deformable plate is any one of copper, an alloy containing copper as a main component, nickel, and an alloy containing nickel as a main component.
8. The power storage device according to claim 6 or 7, wherein a material of the deformation plate and a material of the member to be joined are the same material.
9. The power storage device according to claim 8, wherein a material of the deformation plate is the same material as that of the negative electrode terminal.
10. The power storage device according to any one of claims 1 to 9, wherein the power storage device is a secondary battery.

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