JP2014022283A - Power storage element and power storage element system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short-circuit element which, when abnormality occurs in a power storage element causing the internal temperature to rise excessively, can surely short-circuit a cathode and an anode to discharge electricity stably.SOLUTION: A power storage element 10 of the present invention comprises an electrode body 120, a short-circuit element 150 for short-circuiting a cathode 122 and an anode 123, and a first container 100 for housing the electrode body and the short-circuit element therein. The short-circuit element 150 includes a first electric conductor 151 on the cathode side, a second electric conductor 152 on the anode side, a melting layer 153 having an insulator film 154 and a low melting point alloy layer 155 disposed between the insulator film 154 and the first electric conductor and/or the second electric conductor, and a short-circuit container 160 for housing the first electric conductor, the second electric conductor and the melting layer therein. The melting layer short-circuits the first electric conductor and the second electric conductor by reason that part or the whole of the low melting point alloy layer is fused at a prescribed temperature or below.

Description

  The present invention suppresses excessive temperature rise and pressure rise by discharging the energy of the electricity storage device stably and quickly by short-circuiting the positive electrode and the negative electrode when an abnormal temperature rise occurs in the electricity storage device. It relates to a power storage element capable of

  In recent years, lithium ion batteries having high energy density and high safety have been demanded as batteries for electric vehicles and power storage.

  In such a lithium ion battery having a high energy density, the temperature inside the battery excessively increases or the internal pressure of the battery significantly increases and the battery case is deformed when an abnormality such as overcharge or internal short circuit occurs. There is a case. In such a case, in order to quickly suppress an increase in the temperature or internal pressure of the battery, a method of releasing energy by short-circuiting the battery can be considered.

  In Patent Document 1, a battery is provided with a short-circuit mechanism including a plate-like positive electrode terminal, a plate-like negative electrode terminal, and an insulating layer sandwiched and connected between the positive electrode terminal and the negative electrode terminal. This insulating layer has a function of electrically connecting the positive electrode terminal and the negative electrode terminal by melting at a predetermined temperature or higher. As a result, when the abnormality occurs in the battery and the temperature exceeds a predetermined temperature, the short-circuit mechanism short-circuits the positive electrode and the negative electrode of the battery and releases the energy of the battery to suppress the increase in the temperature or the internal pressure of the battery. .

  Moreover, in patent document 2, when the temperature of a battery rises by utilizing the NTC element whose resistance value decreases as the temperature rises as an insulating member that performs insulation between a lid plate that is a positive electrode terminal and a negative electrode terminal. The resistance of the insulating member is reduced and the positive and negative electrodes are short-circuited. Furthermore, Patent Document 2 discloses a switch that short-circuits the positive electrode terminal and the negative electrode terminal when the temperature of the battery rises by using bimetal.

  Patent Document 3 discloses a battery in which a low melting point alloy is disposed in each of a casing (battery can) electrically connected to the negative electrode and a battery lid electrically connected to the positive electrode. ing. In this battery, when an abnormality occurs in the battery and the temperature exceeds a predetermined temperature, the low-melting point alloy melts and is short-circuited by electrically connecting the housing and the battery lid.

  Patent Document 4 discloses a battery in which a low melting point alloy electrically connected to the positive electrode is disposed around the negative electrode terminal. In this battery, when an abnormality occurs in the battery and the temperature exceeds a predetermined temperature, the low melting point alloy melts to contact the negative electrode terminal, and the positive electrode and the negative electrode are electrically connected to make a short circuit.

  Further, Patent Document 5 discloses a secondary battery that short-circuits the positive electrode terminal portion and the negative electrode terminal portion inside the battery by melting the heat-melting member when the temperature exceeds a predetermined temperature.

  As described in Patent Documents 1 to 5, when excessive heat is generated due to abnormality of the battery, the battery is connected by short-circuiting the positive electrode terminal and the negative electrode terminal in a short circuit mechanism (including a low melting point alloy), thereby Energy from the battery.

JP 2008-130458 A JP 2005-044626 A JP 2006-228520 A JP 2009-76270 A Japanese Patent No. 4751500

  When the storage element is abnormal, it is necessary to discharge with a large current and quickly release the energy of the storage element in order to quickly suppress the temperature rise and internal pressure increase of the storage element. Difficult from the following viewpoints.

  In the technique such as Patent Document 1, since the insulating layer is sandwiched between the plate-like positive electrode terminal and the plate-like negative electrode terminal, the insulating layer comes off when an impact such as vibration is applied, which is unexpected. It cannot be denied that a short circuit occurs, and there is a problem in terms of vibration resistance and impact resistance. In addition, this short-circuit mechanism is based on the premise that an urging force can be applied from the outside to the positive electrode terminal and the negative electrode terminal, and even if the insulating layer melts, a melt of the insulating layer is interposed due to the urging force from the outside, The resistance value is difficult to reduce. For this reason, with this configuration, it is difficult to reliably short-circuit and discharge. Further, in the technique such as Patent Document 1, there is a problem of stability and reproducibility of the resistance value when the short circuit mechanism (short circuit element) is short-circuited, so that it is difficult to discharge urgently when the battery is abnormal.

  Further, in the technique using the NTC element of Patent Document 2, since a minute current continues to flow even during normal use, the self-discharge amount as the battery system becomes large, which is not preferable.

  Similarly, in the technique using the bimetal switch of Patent Document 2, since the positive electrode terminal and the negative electrode terminal are short-circuited by the bimetal switch, the short-circuited portion is structurally one point. However, in the bimetal switch, the location where the short circuit occurs is structurally one point as described above, so that it is difficult to flow a large current and it is difficult to ensure the short circuit performance. In order to increase the area of the short-circuited portion of the bimetal switch to make the battery safer, there is a problem that the bimetal switch needs to be enlarged and the production cost increases. Further, in the case of a bimetal switch, a portion that is not originally in contact with each other is short-circuited when the temperature rises and the switch portion is deformed and contacted. That is, in applications where vibration resistance and impact resistance are required, it is difficult to obtain stable insulation performance, and it is considered that there is a problem in the reliability of the short-circuit element.

  Further, in the techniques such as Patent Document 3 and Patent Document 4, the portion where the positive electrode and the negative electrode are short-circuited is small. That is, the resistance in the short circuit path when the positive electrode and the negative electrode are short-circuited is not sufficiently small. For this reason, it is difficult to discharge with a large current from the short-circuited portion, and if a large current is to flow, it is necessary to enlarge the portion of the short-circuited portion.

  Moreover, in the technique like patent document 5, since the negative electrode terminal part is being fixed with the spring, there exists a possibility of act | operating by external impacts, such as a vibration.

  Therefore, the present invention has been made in view of such a situation, and when an abnormality occurs and the internal temperature rises excessively, the positive electrode and the negative electrode are short-circuited reliably and stably and promptly. It is an object of the present invention to provide a power storage element that can be discharged.

  To achieve the above object, a power storage device according to an aspect of the present invention accommodates an electrode body, a short-circuit element for short-circuiting a positive electrode and a negative electrode of the electrode body, and the electrode body and the short-circuit element. A first container, wherein the short-circuit element is electrically connected to the positive electrode side of the electrode body, and the second electric conductor is electrically connected to the negative electrode side of the electrode body. A body, an insulator disposed between the first electrical conductor and the second electrical conductor, and between the insulator and at least one of the first electrical conductor and the second electrical conductor. A molten layer having a low-melting-point alloy layer, a first container containing the first electric conductor, the second electric conductor, and the molten layer, and the molten layer Is that part or all of the low melting point alloy layer melts at the predetermined temperature or higher. More, thereby short-circuiting the said said first electrical conductor second electrical conductor.

  According to this, the electrode body and the short-circuit element are disposed inside the first container. In the short-circuit element, the molten layer is composed of a low melting point alloy that can conduct current and an insulator that does not conduct current, and the low melting point alloy layer is partially or entirely at a predetermined temperature or higher. By melting, the first electrical conductor and the second electrical conductor are short-circuited. That is, the low melting point alloy layer is melted, and the melted low melting point alloy enters, for example, a hole provided in the insulator in advance, or a gap generated by the deformation of the insulator, and the like. Two electrical conductors are brought into conduction. For this reason, a fusion layer short-circuits the 1st electric conductor and the 2nd electric conductor.

  Thus, since the short circuit element is accommodated in the first container, it is directly affected by the temperature inside the power storage element that becomes high when an abnormality occurs in the power storage element. For this reason, when the abnormality occurs in the storage element and the temperature becomes high, the short-circuit element quickly brings the first electric conductor and the second electric conductor into a conductive state, thereby causing the positive electrode and the negative electrode of the electrode body to Can be short-circuited.

  The short-circuit element includes a first electrical conductor other than the end electrically connected to the positive electrode side, a second electrical conductor other than the end electrically connected to the negative electrode side, and a second molten layer Since it is accommodated in the container, the molten layer can be prevented from coming into contact with the electrolytic solution provided inside the electric storage element. Thereby, it can prevent that the performance of an electrical storage element falls because the low melting-point alloy of a molten layer melt | dissolves with respect to electrolyte solution. In addition, since the short-circuit element includes the second container, the positional relationship among the first electric conductor, the second electric conductor, and the molten layer is broken by an external impact such as vibration, and the first electric conductor and the first electric conductor It has a structure in which the two electrical conductors are not easily short-circuited. For this reason, it is possible to reduce malfunction of the short-circuit element, and the short-circuit element can maintain stable insulation performance under an environment below a predetermined temperature even in applications where vibration resistance and impact resistance are required.

  From the above, when an abnormality occurs and the internal temperature rises excessively, the power storage element can be reliably discharged by short-circuiting the positive electrode and the negative electrode.

  The short-circuit element may be provided inside the electrode body.

  According to this, since the power storage element is provided inside the electrode body that is likely to become high temperature when the power storage element is in an abnormal state, the first electric conductor is quickly provided when the power storage element is in an abnormal state. And the second electrical conductor are short-circuited to release the energy inside the electricity storage device, whereby the temperature rise and pressure rise of the electricity storage device can be reduced.

  The electrode body is a wound body that is wound around the core so that a core, the positive electrode and the negative electrode, and a separator disposed between the positive electrode and the negative electrode are laminated. The short-circuit element may be provided inside the core.

  According to this, the electrode body is a wound electrode body that is wound around a core so that the positive electrode, the negative electrode, and the separator are laminated. And a short circuit element is provided in the inside of the winding core arrange | positioned in the innermost periphery of a wound-type electrode body. For this reason, since the power storage element is provided at the center of the electrode body that is likely to reach the highest temperature when the power storage element is in an abnormal state, the first electrical conductor and By short-circuiting the second electrical conductor and releasing the energy inside the power storage element, it is possible to reduce the temperature rise and pressure rise of the power storage element.

  The short-circuit element is provided between the electrode body and the inner wall of the first container, and the one having higher thermal conductivity between the first electric conductor and the second electric conductor You may arrange | position so that it may face the electrode body side.

  According to this, since the short circuit element is arranged so that the higher thermal conductivity of the first electric conductor and the second electric conductor faces the electrode body side, an abnormality occurs in the power storage element. When the electrode body becomes high temperature, the heat generated in the electrode body can be quickly transmitted to the short-circuit element. For this reason, the short-circuit element can quickly short-circuit the positive electrode and the negative electrode of the electrode body when the power storage element becomes high temperature.

  Further, the low melting point alloy layer may be welded or bonded to at least one of the first electric conductor and the second electric conductor.

  As described above, the low-melting point alloy layer is previously welded or bonded to at least one of the first electric conductor and the second electric conductor, so that the first electric material previously welded or bonded to the low-melting point alloy layer is obtained. The compatibility of the conductor or the second electric conductor with the molten low melting point alloy is improved, and when the abnormality occurs in the electric storage element, the electric storage element becomes hot and the low melting point alloy melts, the first electric conductor Alternatively, the electrical connection between the second electric conductor and the molten low melting point alloy can be made more reliable.

  Further, at least one of the first electric conductor and the second electric conductor may be formed of a mesh member.

  According to this, since at least one of the first electric conductor and the second electric conductor is composed of a mesh-like metal member, a large surface area can be secured, and the melted low-melting-point alloy can be used as a mesh-like metal. It is a structure that can be easily held in a gap formed inside the member. As described above, when the mesh-like metal member is brought into contact with the molten low melting point alloy, the meshed metal member can be maintained while holding the molten low melting point alloy, so that the first electric conductor and the second electric conductor are electrically connected. Can be kept connected. For this reason, when an abnormality occurs in the power storage element and the power storage element becomes high temperature, the short-circuit element can quickly electrically connect the first electrical conductor and the second electrical conductor. Moreover, since the short circuit element can maintain the state in which the first electric conductor and the second electric conductor are electrically connected, the energy of the power storage element can be stably discharged.

  The low melting point alloy layer may be constituted by a low melting point alloy and a frame-shaped member that surrounds the outside of the low melting point alloy in a direction perpendicular to the thickness direction of the low melting point alloy layer.

  According to this, the low melting point alloy layer is provided with a frame-shaped member outside the low melting point alloy layer in the direction perpendicular to the thickness direction of the low melting point alloy layer. In this case, it is possible to prevent the molten low melting point alloy from flowing out of the position of the molten layer before operating the short-circuit element.

  The frame member may be made of an elastic material.

  For this reason, since the frame-shaped member can be contracted in accordance with the pressure even when pressure is applied from the outside, for example, the molten low melting point alloy can be prevented from flowing out of the frame-shaped member. .

  The short-circuit element is further disposed on the outer side of at least one of the first electric conductor and the second electric conductor, and expands in the vicinity of the predetermined temperature, and the thermal expansion member And an expansion suppressing member that suppresses expansion of a volume of the first electric conductor, the second electric conductor, and the molten layer.

  According to this, the short-circuit element is in a state where the expansion combined member suppresses the combined volume of the thermally expandable material, the first electric conductor, the second electric conductor, and the molten layer from expanding. . That is, if an abnormality occurs in the storage element, the storage element becomes high temperature, and the thermally expandable material expands, the volume of the thermal expansion member, the first electrical conductor, the second electrical conductor, and the molten layer combined Since the expansion is suppressed by the expansion suppressing member, pressure is applied in a direction in which the first electric conductor and the second electric conductor approach each other. For this reason, the first electric conductor and the second electric conductor can be easily electrically connected by the molten low melting point alloy.

  The insulator has a hole, and the molten layer melts the low melting point alloy layer and flows into the hole of the insulator, whereby the first electric conductor and the second conductor are formed. You may short-circuit with an electrical conductor.

  According to this, the hole is formed in the insulator, and the first electric conductor and the second electric conductor are short-circuited by melting the low melting point alloy layer and flowing into the hole of the insulator. For this reason, the part electrically connected with a 1st electrical conductor and a 2nd electrical conductor can be increased, and it can short-circuit more reliably. Moreover, since the location where the 1st electrical conductor and the 2nd electrical conductor are electrically connected can be increased, more electric current can be sent. Therefore, the positive electrode terminal and the negative electrode terminal can be reliably short-circuited and stably discharged.

  In addition, the molten layer may cause the first electrical conductor and the second electrical conductor to be short-circuited by melting the low-melting-point alloy layer and deforming part or all of the insulator. Also good.

  According to this, when a part or all of the insulator is deformed, a gap (hole) into which the melted low melting point alloy layer flows is formed. For this reason, the molten layer can efficiently short-circuit the first electrical conductor and the second electrical conductor when the temperature reaches a predetermined temperature or higher. Thereby, the part electrically connected with a 1st electrical conductor and a 2nd electrical conductor can be increased, and it can short-circuit more reliably. Moreover, since the location where the 1st electrical conductor and the 2nd electrical conductor are electrically connected can be increased, more electric current can be sent. Therefore, the positive electrode terminal and the negative electrode terminal can be reliably short-circuited and stably discharged.

  The molten layer may be formed by laminating the insulator and the low melting point alloy layer.

  Further, the present invention is not only realized as such a storage element, but also a storage element system comprising a storage element group in which a plurality of storage elements are connected in series and / or in parallel, wherein the plurality of storage elements At least one of these can also be realized as a power storage element system that is the power storage element described above.

  According to the electricity storage device of the present invention, when an abnormality occurs in the electricity storage device and the temperature inside the battery rises excessively, the positive electrode and the negative electrode of the electrode body are reliably short-circuited to discharge stably and quickly. Further, it is possible to suppress further temperature rise and pressure rise of the power storage element.

It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on embodiment. It is a perspective view which shows the structure at the time of isolate | separating the container main body of an electrical storage element. It is a perspective view which shows typically the external appearance of an electrode body, and the short circuit element arrange | positioned in the inside. It is a perspective view which shows typically the external appearance of a short circuit element. It is VV sectional drawing of the short circuiting element in FIG. It is a figure which shows the structure at the time of isolate | separating the container main body of the electrical storage element which concerns on a modification (1). It is a figure which shows the structure at the time of isolate | separating the container main body of the electrical storage element which concerns on the other form of a modification (1). It is VIII-VIII sectional drawing in FIG. 4 of the short circuiting element which concerns on a modification (2). It is a disassembled perspective view of the component except the short circuit container of the short circuit element which concerns on a modification (2). It is XX sectional drawing of the short circuiting element in FIG. 4 which concerns on a modification (3). It is XI-XI sectional drawing of the short circuiting element in FIG. 4 which concerns on a modification (5). It is XII-XII sectional drawing of the short circuit element in FIG. 11 which concerns on a modification (5), and is a figure which shows the state before reaching predetermined temperature, and the state when reaching predetermined temperature. It is a disassembled perspective view of the component except the short circuit container of the short circuit element which concerns on a modification (6). It is a perspective view which shows typically the external appearance of the electrical storage element system which concerns on a modification (12).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are examples, and are not intended to limit the present invention. The invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

(Embodiment)
FIG. 1 is a perspective view schematically showing the external appearance of a power storage element. FIG. 2 is a perspective view showing a configuration when the container body of the electricity storage element is separated. FIG. 3 is a perspective view schematically showing the outer appearance of the electrode body and the short-circuit element disposed therein.

  The storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte battery such as a lithium ion secondary battery.

  As shown in the figure, the power storage device 10 includes a power storage container 100 as a first container, a positive electrode terminal 200, and a negative electrode terminal 300. The power storage container 100 includes a cover plate 110 and a container body 111 that are upper walls. And. In addition, the storage container 100 accommodates an electrode body 120, a short-circuit element 150, a positive electrode current collector 130, and a negative electrode current collector 140. That is, the electrical storage element 10 includes an electrode body 120, a short-circuit element 150, and an electrical storage container 100 as a first container.

  In addition, although electrolyte etc. are enclosed with the inside of the electrical storage container 100 of the electrical storage element 10, illustration is abbreviate | omitted. Moreover, the electrical storage element 10 is not limited to a non-aqueous electrolyte battery, and may be a secondary battery other than the non-aqueous electrolyte battery or a capacitor.

  The power storage container 100 includes a container main body 111 having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid plate 110 that closes the opening of the container main body 111. 1 and 2, the cover plate 110 and the container body 111 are arranged side by side along the Z-axis direction (vertical direction). The cover plate 110 is a rectangular plate-like member, and its longitudinal direction is along the Y-axis direction, and its short direction is along the X-axis direction. In addition, the storage container 100 can seal the inside by accommodating the electrode body 120 and the like and then welding the lid plate 110 and the container body 111.

  The electrode body 120 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, the electrode body 120 is formed by winding the negative electrode and the positive electrode with a separator interposed therebetween so that the separator is sandwiched between the negative electrode and the positive electrode, and has an oval shape as a whole. In addition, in the same figure, although the ellipse shape was shown as a shape of the electrode body 120, circular shape or elliptical shape may be sufficient.

  The short-circuit element 150 is an element that is disposed inside the electrode body 120 and short-circuits the positive electrode and the negative electrode of the electrode body 120. The short-circuit element 150 is electrically connected to the positive electrode side and the negative electrode side of the electrode body 120.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 120, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 120. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 120 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 120, It is an electrode terminal made of metal for introducing. The positive electrode terminal 200 and the negative electrode terminal 300 are attached to a lid plate 110 disposed above the electrode body 120.

  The positive electrode current collector 130 is disposed between the positive electrode of the electrode body 120 and the side wall (wall disposed at the end in the Y-axis direction) of the storage container 100, and is electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 120. It is a member having conductivity and rigidity that are connected to each other. The positive electrode current collector 130 is made of aluminum, like the positive electrode of the electrode body 120.

  The negative electrode current collector 140 is disposed between the negative electrode of the electrode body 120 and the side wall of the storage container 100, and has conductivity and rigidity electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 120. It is a member. The negative electrode current collector 140 is made of copper, like the negative electrode of the electrode body 120.

  As shown in FIG. 3, the electrode body 120 includes a wound body 121 and a winding core 126. The wound body 121 is wound around a winding core such that a positive electrode 122 and a negative electrode 123 and a first separator 124 and a second separator 125 disposed between the positive electrode 122 and the negative electrode 123 are laminated. More specifically, in the electrode body 120, the core 126 is formed such that the positive electrode 122, the first separator 124, the negative electrode 123, and the second separator 125 are laminated in this order, and the cross section has an oval shape. It is formed by being wound around the outer periphery of. The short-circuit element is provided inside the electrode body 120 and inside the core 126.

  More specifically, the positive electrode 122 and the negative electrode 123 are shifted from each other in the long band-like width direction (Y-axis direction) via the separators 124 and 125, and are formed in an oval shape around the rotation axis along the width direction. It has been turned. Then, the positive electrode 122 and the negative electrode 123 each have an edge portion in the shifting direction as a non-formation portion of the active material layer, so that the positive electrode base in which the positive electrode active material layer is not formed on one end side of the winding shaft. The aluminum foil that is the material is exposed, and the copper foil that is the negative electrode base material on which the negative electrode active material layer is not formed is exposed on the other end side of the winding shaft. That is, a part on one end side in the Y-axis direction of the electrode body 120 is a positive electrode connection portion 127 where only an aluminum foil as a positive electrode base material is exposed, and a part on the other end side in the Y-axis direction of the electrode body 120 is This is the negative electrode connection portion 128 where only the copper foil as the negative electrode substrate is exposed. Further, the positive electrode current collector 130 and the negative electrode current collector 140 are disposed at both ends in the winding axis direction (Y-axis direction) of the electrode body 120 in a direction perpendicular to the winding axis direction (Y-axis direction) (Z-axis direction). It extends and is arranged. The positive electrode current collector 130 is electrically connected to the positive electrode connection portion 127 of the electrode body 120, and the negative electrode current collector 140 is electrically connected to the negative electrode connection portion 128 of the electrode body 120.

  The positive electrode 122 is obtained by forming a positive electrode active material layer on the surface of a long belt-shaped positive electrode current collector sheet made of aluminum. In addition, the positive electrode 122 used for the electrical storage element 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

For example, as the positive electrode active material, a polyanion compound such as LiMPO4, Li ₂ MSiO4, LiMBO3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, Spinel compounds such as lithium manganate, lithium such as Li _{1 + α} M _1-α O2 (0 ≦ α <1, M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) Transition metal oxides or the like can be used.

  The negative electrode 123 is obtained by forming a negative electrode active material layer on the surface of a long strip negative electrode current collector sheet made of copper. Note that the negative electrode 123 used in the electricity storage device 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

For example, as the negative electrode active material, a known material can be appropriately used as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, lithium metal and lithium alloys (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys) and lithium can be occluded / released. Alloy, carbon material (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxide, lithium metal oxide (Li ₄ Ti ₅ O ₁₂ etc.), polyphosphate compound Etc.

  The winding core 126 is made of a long strip material having insulation properties such as polypropylene and polyethylene. The winding core 126 is a member that serves as a winding shaft when the positive electrode 122, the negative electrode 123, and the separators 124 and 125 are wound. As shown in FIG. 3, a short-circuit element 150 is provided inside the winding core 126. The short-circuit element 150 will be described later with reference to FIGS. 4 and 5.

  FIG. 4 is a perspective view schematically showing the external appearance of the short-circuit element 150. 5 is a VV cross-sectional view of the short-circuit element 150 in FIG. As shown in the figure, the short-circuit element 150 includes a first electric conductor 151, a second electric conductor 152, a molten layer 153, and a short-circuit container 160 as a second container.

  The first electric conductor 151 is a long plate-like metal member extending in the Y-axis direction, and is made of aluminum in the present embodiment. The first electric conductor 151 is electrically connected to the positive electrode current collector 130 together with the positive electrode connecting portion 127 that is the positive electrode side of the electrode body 120. The second electric conductor 152 is a long plate-like metal member extending in the Y-axis direction, and is made of copper in the present embodiment. The second electric conductor 152 is electrically connected to the negative electrode current collector 140 together with the negative electrode connection portion 128 that is the negative electrode side of the electrode body 120.

  The molten layer 153 includes an insulator film 154 as an insulator and a low melting point alloy layer 155. The insulator film 154 is disposed between the first electric conductor 151 and the second electric conductor 152. The low melting point alloy layer 155 is disposed between the insulator film 154 and the second electric conductor 152. The low melting point alloy layer 155 is not limited to be disposed between the insulator film 154 and the second electric conductor 152, but may be the insulator film 154, the first electric conductor 151, and the second electric conductor. 152 may be disposed between at least one of 152, and may be disposed between the insulator film 154 and the first electric conductor 151, or may be disposed between the insulator film 154, the first electric conductor 151, and the second electric conductor 151. You may arrange | position between both of the electrical conductors 152. The molten layer 153 insulates the first electrical conductor 151 and the second electrical conductor 152 below a predetermined temperature, and at least a part or all of the low melting point alloy layer 155 melts above the predetermined temperature, One electrical conductor 151 and the second electrical conductor 152 are short-circuited.

  The low melting point alloy layer 155 is preferably an alloy having a melting point of 70 to 250 ° C., more preferably an alloy having a melting point of 70 to 150 ° C., and a more optimal melting point of 70 to 120 ° C. When the melting point of the low melting point alloy layer 155 is 70 to 250 ° C., for example, when the temperature inside the power storage element 10 is measured for the short-circuit element 150 and the temperature inside the power storage element 10 becomes equal to or higher than a predetermined temperature. This is effective when the short-circuit element 150 is intentionally short-circuited by positively heating with a heating means such as a heater. In addition, when the melting point of the low melting point alloy layer 155 is 70 to 150 ° C., it is particularly effective from the viewpoint of suppressing the expansion of the storage element due to the evaporation of the electrolyte in the capacitor or the high safety type lithium battery. Further, when the melting point of the low melting point alloy layer 155 is 70 to 120 ° C., it is effective in a general lithium battery.

  The low melting point alloy layer 155 is, for example, a low melting point solder containing tin (Sn) or lead (Pb). The alloy used for the low melting point alloy layer 155 may be 150 ° C. or higher. For example, an alloy having a melting point of 200 ° C. is effective. The low-melting-point alloy layer 155 is an insulator film 154 that is a layer in which a low-melting-point alloy is mixed with a fluxing agent or is in contact with the low-melting-point alloy layer 155 (hereinafter referred to as “contact layer”). Alternatively, it is preferable to apply a fluxing agent to the first electric conductor 151 and the second electric conductor 152 in advance. Thus, by using the flux agent, the wettability between the low melting point alloy layer 155 and the contact layer is improved, and the power storage element can be more stably short-circuited. Further, the low melting point alloy layer 155 can be easily applied in the form of a layer on the surface of the contact layer. As the fluxing agent, for example, a rosin-based fluxing agent containing at least one of organic acids, amines, halides and the like as an activator can be used.

  The insulator film 154 is a thin-film insulator and has a plurality of holes. The insulator film 154 is preferably made of a material having a melting point of 150 ° C. or higher, such as silicon rubber or Teflon (registered trademark) resin. The insulator film 154 is also preferably silicon rubber that has wettability to the alloy of the low melting point alloy layer 155. Note that the melting point of the insulator film 154 is preferably higher than the melting point of the low melting point alloy layer 155. For example, in the case where the material of the insulator film 154 is 70 to 250 ° C. which is the same melting point as that of the low melting point alloy layer 155, an unnecessary short circuit is caused by deformation (particularly shrinkage) at a temperature lower than the melting point. It is not preferable. Since the insulator film 154 is a member that substantially insulates the first electric conductor 151 and the second electric conductor 152, when the temperature is lower than the temperature at which the short circuit is intended (that is, a predetermined temperature) It is required to insulate the two reliably and to short-circuit them reliably when the temperature exceeds a predetermined temperature. That is, it is preferable that the insulator film 154 is thinner and has a larger area ratio of holes in a state where the first electric conductor 151 and the second electric conductor 152 are reliably insulated. In order to increase the ratio of the hole area, it is conceivable to increase the number of holes and to increase the size of one hole. Note that although the insulator film 154 having holes is shown here as an insulator, the present invention is not limited to this, and any insulating and porous material may be used as long as it is made of an insulating material. A net or mesh porous body (that is, a net-like material) can be used.

  The short-circuit container 160 is a container that houses the first electric conductor 151, the second electric conductor 152, and the molten layer 153, and is made of an aluminum laminate film. The aluminum laminate film constituting the short-circuit container 160 is a rectangular flexible laminate film having a three-layer structure in which a base film layer is laminated on one surface of a metal layer and a sealant layer is laminated on the other surface. The metal layer is made of an aluminum foil, and is an intermediate layer provided in order to secure the gas barrier property of the short-circuit container 160 and reliably prevent the nonaqueous electrolyte from entering. The base film layer is an outer layer made of a resin layer such as nylon and provided to increase the strength of the short circuit container 160. Further, the sealant layer is an inner layer made of a thermoplastic resin such as polypropylene and provided to thermally weld the peripheral edge of the aluminum laminate film. The short-circuit container 160 may be composed of one aluminum laminate film or may be composed of two aluminum laminate films.

  In the state in which the short-circuit element 150 is accommodated in the short-circuit container 160, a part of the first electric conductor 151 is exposed from one of the end portions in the Y-axis direction, and the second from the other end portion in the Y-axis direction. A part of the electric conductor 152 is exposed. In the short-circuit element 150, a part of the first electric conductor 151 exposed from the short-circuit container 160 is electrically connected to the positive electrode current collector 130, and the short-circuit element 150 is exposed from the short-circuit container 160 of the second electric conductor 152. And the negative electrode current collector 140 are electrically connected.

  In addition, when the molten layer 153 is configured as the short-circuit element 150, it is between the first electric conductor 151 and the second electric conductor 152, and the first electric conductor 151 and the second electric conductor 152. Are disposed at least in a region where the two overlap with each other (hereinafter referred to as a “short-circuit region”). By disposing the molten layer 153 in this way, the first electric conductor 151 and the second electric conductor 152 are electrically insulated by the insulator film 154 inside the short-circuit element 150.

When the molten layer 153 reaches or exceeds a predetermined temperature (in this embodiment, one of 70 to 150 ° C. and the melting point of the low melting point alloy layer 155), the low melting point alloy layer 155 is melted and insulated. By flowing into the hole of the body film 154, the first electric conductor 151 and the second electric conductor 152 are short-circuited. At this time, the resistance value (Ω) of the short-circuit element 150 is reduced by 9 digits or more compared to before the short-circuit. That is, normally, the short-circuit element 150 needs to be substantially insulative in order to reduce the self-discharge of the power storage element, and preferably has a high resistance of 1 MΩ or more. On the other hand, the short-circuit element 150 needs to short-circuit between the terminals with a low resistance because it is necessary to rapidly discharge the power storage element and release the energy in the battery in the short-circuit state. The resistance value at the time of short circuit differs depending on the battery voltage at the start of discharge, the capacity of the battery and the magnitude of the short circuit current to be set, but the resistance value of the short circuit element should be reduced by 6 digits or more compared to before the short circuit. Is desirable. More specifically, the resistance value R [Ω] at the time of short circuit is R = x / yz (where x is the battery voltage [V], y is the battery capacity (Ah), z is the value of the short circuit current / battery capacity ( It is desirable to set the value calculated from h ⁻¹ )). Thus, by making the resistance change of the short-circuit element 150 before and after the short circuit to be 6 digits or more, the normal self-discharge can be reduced and the battery can be rapidly discharged at the time of the short-circuit.

  According to power storage element 10 according to the present embodiment, electrode body 120 and short-circuit element 150 are arranged inside power storage container 100. In the short-circuit element 150, the molten layer 153 includes a low melting point alloy layer 155 capable of conducting current and an insulator film 154 that does not conduct current, and the low melting point alloy layer 155 has a predetermined temperature. By melting part or all of the above, the first electrical conductor 151 and the second electrical conductor 152 are electrically connected and short-circuited. That is, when the low melting point alloy layer 155 is melted and the melted low melting point alloy layer 155 enters, for example, a hole or the like provided in the insulator film 154 in advance, the first electric conductor 151 and the second electric conductor 152 Is made conductive. For this reason, the molten layer 153 short-circuits the first electric conductor 151 and the second electric conductor 152.

  As described above, since the short-circuit element 150 is housed inside the power storage container 100, the short-circuit element 150 is directly affected by the temperature inside the power storage element 10 that becomes high when an abnormality occurs in the power storage element 10. For this reason, the short-circuit element 150 quickly brings the first electric conductor 151 and the second electric conductor 152 into a conductive state when an abnormality occurs in the power storage element 10 and the temperature becomes high. The positive electrode 122 and the negative electrode 123 can be short-circuited.

  The short-circuit element 150 includes a first electric conductor 151 other than the end portion electrically connected to the positive electrode side, a second electric conductor 152 other than the end portion electrically connected to the negative electrode side, and a molten layer Since 153 is accommodated in the short-circuit container 160, the molten layer 153 can be prevented from coming into contact with the electrolytic solution provided inside the power storage element 10. Thereby, it can prevent that the performance of the electrical storage element 10 falls because the low melting-point alloy layer 155 of the fusion | melting layer 153 melt | dissolves with respect to electrolyte solution. In addition, since the short-circuit element 150 includes the short-circuit container 160 as the second container, the positional relationship between the first electric conductor 151, the second electric conductor 152, and the molten layer 153 is caused by external impact such as vibration. The first electric conductor 151 and the second electric conductor 152 are not easily short-circuited. For this reason, it is possible to reduce malfunction of the short-circuit element 150, and the short-circuit element 150 can maintain stable insulation performance under an environment below a predetermined temperature even in applications where vibration resistance and impact resistance are required.

  As described above, the storage element 10 can reliably discharge the positive electrode 122 and the negative electrode 123 by short-circuiting when the abnormality occurs and the internal temperature rises excessively.

  Moreover, according to the electricity storage element 10 according to the present embodiment, the electricity storage element 10 is abnormal because the electricity storage element 10 is provided inside the electrode body 120 that tends to become high temperature when the electricity storage element 10 is in an abnormal state. In such a case, the first electrical conductor 151 and the second electrical conductor 152 are quickly short-circuited to release the energy in the energy storage device 10, thereby increasing the temperature and pressure of the energy storage device 10. Can be reduced.

  Further, according to power storage device 10 according to the present exemplary embodiment, electrode body 120 is wound around winding core 126 so that positive electrode 122 and negative electrode 123 and separators 124 and 125 are laminated. This is a wound electrode body. The short-circuit element 150 is provided inside the winding core 126 disposed on the innermost periphery of the wound electrode body 120. For this reason, since the electrical storage element 10 is provided at the center of the electrode body 120 that is likely to become high temperature when the electrical storage element 10 is in an abnormal state, the first electrical device is promptly provided when the electrical storage element 10 is in an abnormal state. By short-circuiting the conductor 151 and the second electric conductor 152 and releasing the energy inside the electricity storage device 10, the temperature rise and pressure rise of the electricity storage device 10 can be reduced.

  In addition, according to short-circuit element 150 of power storage element 10 according to the present embodiment, holes are formed in insulator film 154, and low melting point alloy layer 155 melts and flows into the holes of insulator film 154. As a result, the first electric conductor 151 and the second electric conductor 152 are short-circuited. For this reason, the part electrically connected with the 1st electrical conductor 151 and the 2nd electrical conductor 152 can be increased, and it can short-circuit more reliably. Moreover, since the location where the 1st electrical conductor 151 and the 2nd electrical conductor 152 are electrically connected can be increased, more electric current can be sent. Therefore, the positive electrode side and the negative electrode side of the electrode body can be reliably short-circuited and stably discharged.

(Modification of the embodiment)
(1)
In the power storage element 10 according to the above embodiment, the short-circuit element 150 is provided inside the electrode body 120. However, the present invention is not limited thereto, and may be provided, for example, as long as it is provided inside the power storage container 100 as the first container. As shown in FIG. 6 or 7, it may be provided outside the electrode body 120.

  FIG. 6 is a diagram showing a configuration when the container body 111 of the electricity storage device 10a according to the modification (1) is separated. FIG. 7 is a diagram showing a configuration when the container body 111 of the electricity storage device 10b according to another form of the modification (1) is separated. In addition, the same code | symbol is attached | subjected to the same component as the electrical storage element 10 which concerns on the said embodiment, and the description is abbreviate | omitted.

  6 and 7, the short-circuit element 150 is provided between the electrode body 120 and the inner wall of the storage container 100, and the first electric conductor 151 and the second electric conductor 152 Among these, it arrange | positions so that the one with higher heat conductivity may face the electrode body 120 side. In the storage element 10 a shown in FIG. 6, the short-circuit element 150 is disposed on the side surface of the electrode body 120 so that the longitudinal direction thereof is along the winding axis direction of the electrode body 120. 7, the short-circuit element 150 is arranged on the bottom surface side of the electrode body 120 so that the longitudinal direction thereof is along the winding axis direction of the electrode body 120. And in electrical storage element 10a, 10b, the short circuit element 150 is arrange | positioned so that the 2nd electrical conductor 152 whose heat conductivity is higher than the 1st electrical conductor 151 may face the electrode body 120 side. In addition, although not shown, the power storage elements 10a and 10b are electrically connected to the positive electrode current collector 130 of the first electrical conductor 151 of the short-circuit element 150 in the same manner as the power storage element 10 according to the above embodiment. Two electric conductors 152 are electrically connected to the negative electrode current collector 140.

  According to the electricity storage elements 10a and 10b according to the modified example (1), the short-circuit element 150 includes the second electric conductor 152 having high thermal conductivity among the first electric conductor 151 and the second electric conductor 152. Since it is arranged so as to face the electrode body 120 side, when an abnormality occurs in the power storage elements 10a and 10b and the electrode body 120 becomes high temperature, the heat generated in the electrode body 120 is quickly transmitted to the short-circuit element 150. be able to. For this reason, the short-circuit element 150 can quickly short-circuit the positive electrode 122 and the negative electrode 123 of the electrode body 120 when the power storage elements 10a and 10b reach a high temperature.

(2)
In the power storage element 10 according to the above embodiment, the low melting point alloy layer 155 that is one of the constituent elements of the short circuit element 150 is a layer of only the low melting point alloy, but the short circuit element 250 shown in FIG. As described above, the low melting point alloy 256 and the frame-shaped member 257 surrounding the outside in the direction perpendicular to the thickness direction of the low melting point alloy layer 255 of the low melting point alloy 256 (that is, the extending direction of the low melting point alloy layer 255) It may be configured. FIG. 8 is a VIII-VIII cross-sectional view of the short-circuit element 250 according to the modification (2) in FIG. FIG. 9 is an exploded perspective view of the constituent elements of the short-circuit element 250 according to the modification (2) excluding the short-circuit container 160. In addition, the same code | symbol is attached | subjected to the same component as the electrical storage element 10, 10a, 10b which concerns on the said embodiment or modification (1), and the description is abbreviate | omitted.

  According to the short-circuit element 250 according to the modified example (2), the molten layer 253 includes the frame-shaped member 257 that surrounds the outside in the extending direction of the low-melting-point alloy 256. Thus, when the power storage element 10 reaches a high temperature, the melted low melting point alloy 256 can be prevented from flowing out of the position of the molten layer before the short circuit element is activated due to the presence of the frame-like member 257. The frame member 257 is preferably made of an elastic material. If the frame-shaped member 257 is made of an elastic material, for example, even if pressure is applied from the outside, the molten low-melting-point alloy 256 flows out to the outside of the frame-shaped member 257 because it can contract according to the pressure. Can be prevented. Further, the frame-like member 257 is elastically deformed if the low-melting-point alloy 256 is melted and can be deformed to prevent the low-melting-point alloy 256 from flowing out of the frame-like member 257 when pressure is applied. The material is not limited to a material that performs plastic deformation, and may be a material that plastically deforms.

(3)
In the electricity storage device 10 according to the above embodiment, the first electric conductor 151 and the second electric conductor 152 which are part of the constituent elements of the short-circuit element 150 are plate-like metal members, but are plate-like members. Without being limited thereto, a mesh-like metal member may be used. 10 is a cross-sectional view taken along line XX in FIG. 4 of the short-circuit element 350 according to the modification (3). A short-circuit element 350 shown in FIG. 10 includes a first electric conductor 351, a second electric conductor 352, a molten layer 153, a positive electrode connection member 353, a negative electrode connection member 354, and a short-circuit container 360. The first electric conductor 351 is a mesh-like metal member and is made of aluminum. The second electric conductor 352 is a mesh-like metal member and is made of copper. The first electric conductor 351, the molten layer 153, and the second electric conductor 352 are stacked in this order.

  The positive electrode connection member 353 is a long plate-like metal member and is made of aluminum. The positive electrode connecting member 353 is a member that electrically connects the first electric conductor 351 and the positive electrode connecting portion 127 of the electrode body 120 and / or the positive electrode current collector 130. The positive electrode connection member 353 has a portion where the end portion is exposed from the short-circuit container 160, and the exposed portion functions as a connection terminal connected to the positive electrode side.

  The negative electrode connection member 354 is made of copper which is a long plate-like metal member. The negative electrode connection member 354 is a member that electrically connects the second electric conductor 352 and the negative electrode connection portion 128 of the electrode body 120 and / or the negative electrode current collector 140. The negative electrode connection member 354 has a portion whose end is exposed from the short-circuit container 160, and the exposed portion functions as a connection terminal connected to the negative electrode side.

  According to the short-circuit element 350 of the electric storage element according to the modified example (3), the first electric conductor 351 and the second electric conductor 352 are made of a mesh-like metal member, so that a large surface area can be secured, and In this structure, the molten low melting point alloy 256 is easily held in a gap formed inside the mesh-like metal member. As described above, when the first electric conductor 351 and the second electric conductor 352 formed of the mesh-shaped metal member are in contact with the molten low melting point alloy 256, the molten low melting point alloy 256 is retained. Since it can maintain, the state where the 1st electric conductor 351 and the 2nd electric conductor 352 were electrically connected can be maintained. For this reason, when an abnormality occurs in the storage element and the storage element becomes high temperature, the short-circuit element 350 can quickly electrically connect the first electrical conductor 351 and the second electrical conductor 352. it can. In addition, the short-circuit element 350 can maintain the state in which the first electric conductor 351 and the second electric conductor 352 are electrically connected, and thus can stably release the energy of the power storage element. . In addition, although both the 1st electrical conductor 351 and the 2nd electrical conductor 352 are made into the mesh-shaped metal member, even if it is any one, it has the effect mentioned above.

(4)
In the electricity storage devices 10, 10 a, and 10 b according to the above embodiments or modifications (1) to (3), the first electric conductor 151 (351) and the second electric conductor 152 (352) are not particularly mentioned. ) May have a low melting point alloy layer 155 (255) welded or bonded thereto.

  As described above, the low melting point alloy layer 155 (255) is previously welded or bonded to at least one of the first electric conductor 151 (351) and the second electric conductor 152 (352), thereby reducing the low melting point. The compatibility of the first electric conductor 151 (351) or the second electric conductor 152 (352) previously welded or bonded to the alloy layer 155 (255) and the molten low melting point alloy is improved, and the electrical connection is improved. This is preferable because it can be made more reliable and can stably short-circuit the storage element.

  Further, the low melting point alloy layer 155 (255) is previously welded or bonded to at least one of the first electric conductor 151 (351) and the second electric conductor 152 (352), so that the low melting point alloy is formed. Since heat is easily conducted, it is possible to quickly short-circuit the power storage elements 10, 10a, and 10b. In addition, the low melting point alloy layer 155 (255) is previously welded or bonded to the higher one of the first electric conductor 151 (351) and the second electric conductor 152 (352) to thereby form an electrode. It is preferable because the heat of the body 120 can be efficiently transmitted to the low melting point alloy layer 155 (255), and the power storage elements 10, 10a, and 10b can be short-circuited more quickly.

(5)
In the short-circuit elements 150, 250, and 350 according to the embodiment, the modification (2), or the modification (3), the first electric conductor 151 (351) and the second electric conductor 152 (352) are brought close to each other. However, the biasing force for bringing the first electrical conductor 351 and the second electrical conductor 352 closer to each other when the electrical contact between them is intended is short-circuited. The element 450 may be used (see FIGS. 11 and 12).

  11 is a cross-sectional view taken along line XI-XI of the short-circuit element 450 in FIG. 4 according to the modification (5). 12 is an XII-XII cross-sectional view of the short-circuit element 450 in FIG. 11 according to Modification (5). 11 includes a first electrical conductor 351, a second electrical conductor 352, a molten layer 253, a positive electrode connection member 353, a negative electrode connection member 354, a thermal expansion member 456, and a short circuit container. 460. That is, the short-circuit element 450 according to the modification (5) functions by adding the thermal expansion member 456 to the configuration of the short-circuit element 350 according to the modification (3) and by adding the thermal expansion member 456. Is different from the short-circuit container 460 to which is added. For this reason, only the thermal expansion member 456 and the short circuit container 460 will be described below.

  The thermal expansion member 456 is disposed outside the first electrical conductor 351 among the multilayered body of the first electrical conductor 351, the molten layer 253, and the second electrical conductor 352, and is near a predetermined temperature. Inflates. Specifically, the thermal expansion member 456 may be, for example, a thermal expansion microcapsule. The thermally expandable microcapsule is composed of a shell made of a thermoplastic resin (for example, acrylonitrile) and a liquid hydrocarbon gas (for example, isobutane) filled in the shell. When the thermally expandable microcapsule is heated to a predetermined temperature or higher, the thermoplastic resin constituting the shell is softened, and the liquid hydrocarbon gas contained in the shell is gasified to increase the internal pressure in the shell. It expands. As described above, when the thermal expansion member 456 is heated to a predetermined temperature, the liquid hydrocarbon gas in the shell expands by gasification. Therefore, the volume of the thermal expansion member 456 immediately after reaching the predetermined temperature is predetermined. It becomes as large as about 50 times the volume of the thermal expansion member 456 before reaching the temperature. The short-circuit container 460 has a volume (hereinafter referred to as “short-circuit element volume”) in which the thermal expansion member 456, the first electric conductor 351, the second electric conductor 352, and the molten layer 253 are combined. It functions as an expansion suppressing member that suppresses this.

  The “near the predetermined temperature” at which the thermal expansion member 456 expands is preferably equal to or lower than a predetermined temperature at which the low melting point alloy 256 melts, and more preferably the same temperature as the predetermined temperature at which the low melting point alloy 256 melts. preferable. However, even if the “near the predetermined temperature” is a temperature higher than the predetermined temperature at which the low melting point alloy 256 melts, the short-circuit element 150 can be short-circuited. That is, when the low-melting-point alloy 256 is melted and the thermal expansion member 456 expands, pressure is applied in a direction in which the first electric conductor 351 and the second electric conductor 352 approach each other, thereby solving the problem. Therefore, the temperature at which the thermal expansion member 456 expands does not have to coincide with the predetermined temperature.

  In addition, although the short circuit container 460 is functioning as an expansion | swelling suppression member, it is not restricted to using the short circuit container 460 if it is a member which can suppress that a short circuit element volume expand | swells not only to this. For example, two plate-like members provided on the outer side of the thermal expansion member 456 and on the outer side of the second electric conductor 352 and two plate-like members connected to the end portions of the two plate-like members. It may be an expansion suppressing member configured with a connecting member that regulates the distance of the member so as to maintain the thickness of the short-circuit element. Further, the thermal expansion member 456 is not limited to being disposed outside the first electric conductor 351 in the multilayer body, and is at least one of the first electric conductor 351 and the second electric conductor 352. If it has been arrange | positioned on the outer side, the arrangement position will not be limited.

  In this way, the thermal expansion member 456 is heated to a predetermined temperature and its volume is about 50 to 100 times, and the short-circuit container 160 includes the thermal expansion member 456, the first electric conductor 351, and the second electric Since the total thickness of the conductor 352 and the molten layer 253 is regulated to be a predetermined thickness, pressure is applied in a direction in which the first electric conductor 351 and the second electric conductor 352 approach each other. become. That is, the biasing force that causes the first electric conductor 351 and the second electric conductor 352 to approach each other in accordance with the timing at which the low melting point alloy 256 of the molten layer 253 is melted by the configuration of the thermal expansion member 456 and the short-circuit container 460. Can be provided to the first electrical conductor 351 and the second electrical conductor 352. For this reason, the melted low melting point alloy can easily connect the first electric conductor and the second electric conductor.

(6)
In the short-circuit element 250 according to the modification (2), the melted layer 253 has substantially the same area when viewed from the X-axis direction of the insulator film 154 and the low-melting-point alloy layer 255 according to FIG. That is, the area of the surface where the insulator film 154 and the low melting point alloy layer 255 are in contact with each other is substantially the same), but is not limited thereto. For example, as shown in FIG. 13, a molten layer 553 that employs an insulator film 554 having a larger area when viewed from the X-axis direction than the low melting point alloy layer 255 may be used. FIG. 13 is an exploded perspective view of the components excluding the short-circuit container of the short-circuit element according to the modification (6). That is, the area of the insulator film 554 is larger than the area of the low melting point alloy layer 255 on the surface where the insulator film 554 and the low melting point alloy layer 255 are in contact with each other. Thus, by configuring the insulator film 554, the size of the insulator film 554 can be made larger than the area of the short-circuit region where the first electric conductor 151 and the second electric conductor 152 overlap, The first electric conductor 151 and the second electric conductor 152 can be configured to be more difficult to contact directly than the configuration of the short-circuit element 250 according to the modification (2). Accordingly, even when an impact such as vibration is applied, it is possible to prevent the first electric conductor 151 and the second electric conductor 152 from being short-circuited under unintended conditions.

(7)
In the short-circuit elements 150, 250, 350, 450 according to the embodiment or the modifications (1) to (6), the molten layers 153, 253 are composed of one insulating film 154 and one low melting point alloy layer 155. However, the present invention is not limited to this. For example, the molten layer may have a three-layer structure in which one insulating film is laminated so that two low-melting-point alloy layers are sandwiched therebetween.

(8)
For example, although not shown, the molten layer may have a coating structure in which the low-melting point alloy layer is coated so as to be wrapped with an insulator coating.

  Note that it is conceivable that the insulating coating when the molten layer has a coating structure employs a material such as an insulating coating agent, a wax material, a heat shrink film, or an electrically insulating paint.

  More specifically, examples of the insulator coating agent include epoxy-based, urethane-based, silicon-based, acrylic-based, or Teflon (registered trademark) -based resins. In this case, when the molten layer reaches a predetermined temperature or higher, the low melting point alloy layer melts and the insulating coating (insulating coating agent) coated on the low melting point alloy layer is torn and collapsed, and the first electric conduction The body and the second electrical conductor are short-circuited when the low melting point alloy layer is electrically connected.

  An example of the wax material is paraffin wax. In this case, when the molten layer reaches a predetermined temperature or more, the low melting point alloy layer is melted, and further, the insulator coating (brazing material) is melted from the gap formed by melting after the low melting point alloy layer is melted or simultaneously. When the alloy is oozed out, the first electric conductor and the second electric conductor are short-circuited when the low melting point alloy layer is electrically connected.

  An example of the heat shrink film is a polystyrene or polyester film. In this case, when the molten layer reaches a predetermined temperature or more, the insulator coating (heat-shrinkable film) is thermally contracted, thereby generating a gap in the insulator coating. At the same time, since the low melting point alloy layer is melted in the molten layer, the molten low melting point alloy layer flows into the gap generated in the insulator coating, and the first electric conductor and the second electric conductor are connected. The low melting point alloy layer is short-circuited by electrical connection.

  In the case of an electrically insulating paint, the molten layer acts in the same manner as in the case of the insulator coating agent, and short-circuits the first electrical conductor and the second electrical conductor.

  According to the short-circuit element of the modified example (8), a part or the whole of the insulator coating is deformed, so that a gap through which the low melting point alloy layer melted in the insulator coating can flow is generated in the insulator coating. For this reason, the molten layer can efficiently short-circuit the first electrical conductor and the second electrical conductor when the temperature reaches a predetermined temperature or higher. Thereby, the location where the 1st electric conductor and the 2nd electric conductor are electrically connected can be increased, and more electric current can be sent. Therefore, the positive electrode terminal and the negative electrode terminal can be reliably short-circuited and stably discharged. Further, when the molten layer is formed by coating the low melting point alloy layer with the insulator coating as in the modified example (8), it can be manufactured at a lower cost than the molten layer of the above embodiment.

(9)
In the short-circuit elements 150, 250, 350, and 450 according to the above-described embodiments or modifications (1) to (8), the first electric conductor 151 (351), the molten layer 153 (253), and the second electric conduction Although the body 152 (352) is laminated in a planar shape, the present invention is not limited to this.

  For example, the short-circuit element may have a wound structure formed by winding a first electric conductor and a second electric conductor in a state of being laminated via a molten layer. A folded structure formed by folding the electric conductor and the second electric conductor in a bellows state in a state where the electric conductor and the second electric conductor are stacked via a melted layer may be used.

  In this way, by configuring the short-circuit element so as to have a wound structure or a folded structure, when the melted layer becomes a predetermined temperature or higher and the low melting point alloy layer melts, the first electric conductor and the second electric conductor The area in contact with the conductor can be increased, and a larger short-circuit current can be passed.

(10)
In the short-circuit elements 150, 250, 350, and 450 according to the above-described embodiments or modifications (1) to (9), the predetermined temperature for short-circuiting the short-circuit elements 150, 250, 350, and 450 is 70 to 250 ° C. For example, it is preferable that it is below the shutdown temperature of the separators 124 and 125 of the electrical storage element 10. Thereby, before the electrical storage element 10 is shut down by the separators 124 and 125, the short circuit elements 150, 250, 350, and 450 are short-circuited, whereby the energy stored in the electrical storage element 10 can be released. For this reason, it is in a lower temperature state, and the energy of the electrical storage element 10 can be rapidly released.

(11)
In the short-circuit elements 150, 250, 350, 450 according to the above-described embodiments or modifications (1) to (10), the first electric conductor 151 (351) is made of aluminum, and the second electric conductor 152 ( 352) is made of copper, but is not limited to this, as long as it has high thermal conductivity. For example, at least one of the first electrical conductor 151 (351) and the second electrical conductor 152 (352) can be selected from aluminum, nickel, iron, copper, stainless steel, nichrome, and other metallic materials. Similarly, the same can be said for the positive electrode connecting member 353 and the negative electrode connecting member 354.

(12)
The short-circuit element 150 of the above embodiment is for short-circuiting the positive electrode side and the negative electrode side of one power storage element 10, but not limited to one power storage element 10, a combination of a plurality of power storage elements 10. You may apply to. For example, a configuration in which a plurality of terminals of the power storage element 10 are connected in series by the terminal connection member 501 as in the power storage element system 500 illustrated in FIG. Further, the power storage device system is not limited to the power storage device system 500 connected in series as shown in FIG. 14 but may be a power storage device system in which a plurality of power storage devices 10 are connected in parallel, or power storage in which series connection and parallel connection are combined. It is good also as an element system.

  The present invention is used as a power storage element or the like that can make the power storage element safe by reliably short-circuiting the positive electrode and the negative electrode only when an abnormality occurs in the power storage element and the temperature inside the battery rises excessively. Can do.

10, 10a, 10b Storage element 100 Storage container 110 Cover plate 111 Container body 120 Electrode body 121 Winding body 122 Positive electrode 123 Negative electrode 124 First separator 125 Second separator 126 Core 127 Positive electrode connection portion 128 Negative electrode connection portion 130 Positive electrode current collector Body 140 Negative electrode current collector 150, 250, 350, 450 Short-circuit element 151, 351 First electric conductor 152, 352 Second electric conductor 153, 253, 553 Molten layer 154, 554 Insulator film 155, 255 Low melting point alloy Layer 160, 360, 460 Short-circuit container 200 Positive electrode terminal 256 Low melting point alloy 257 Frame member 300 Negative electrode terminal 353 Positive electrode connection member 354 Negative electrode connection member 456 Thermal expansion member

Claims (13)

An electrode body;
A short-circuit element for short-circuiting the positive electrode and the negative electrode of the electrode body;
A first container containing the electrode body and the short-circuit element;
With
The short-circuit element is
A first electrical conductor electrically connected to the positive electrode side of the electrode body;
A second electrical conductor electrically connected to the negative electrode side of the electrode body;
An insulator disposed between the first electrical conductor and the second electrical conductor; and between the insulator and at least one of the first electrical conductor and the second electrical conductor. A low melting point alloy layer, and a molten layer,
A first container containing the first electric conductor, the second electric conductor, and the molten layer;
The molten layer is configured to short-circuit the first electric conductor and the second electric conductor by melting a part or all of the low melting point alloy layer at the predetermined temperature or higher. The electric storage element according to claim 1, wherein the short-circuit element is provided inside the electrode body. The electrode body is
Winding core,
A wound body wound around the core so that the positive electrode and the negative electrode and a separator disposed between the positive electrode and the negative electrode are laminated;
Have
The electric storage element according to claim 2, wherein the short-circuit element is provided inside the winding core. The short-circuit element is provided between the electrode body and the inner wall of the first container, and the one having the higher thermal conductivity between the first electric conductor and the second electric conductor is on the electrode body side. The electric storage element according to claim 1, wherein the electric storage element is disposed so as to face. 5. The power storage device according to claim 1, wherein at least one of the first electric conductor and the second electric conductor has the low melting point alloy layer welded or bonded thereto. The power storage device according to any one of claims 1 to 5, wherein at least one of the first electric conductor and the second electric conductor is configured by a mesh-like member. The low melting point alloy layer is
Low melting point alloy,
The power storage device according to any one of claims 1 to 6, comprising: a frame-shaped member that surrounds an outside of the low-melting-point alloy in a direction perpendicular to a thickness direction of the low-melting-point alloy layer. The power storage element according to claim 7, wherein the frame-shaped member is made of an elastic material. The short-circuit element further includes:
A thermal expansion member that is disposed outside at least one of the first electrical conductor and the second electrical conductor and expands in the vicinity of the predetermined temperature;
The expansion | extension suppression member which suppresses expansion | swelling of the volume which match | combined the said thermal expansion member, said 1st electrical conductor, said 2nd electrical conductor, and the said fusion | melting layer. The electrical storage element of 1 item | term. The insulator has a hole,
The melted layer short-circuits the first electrical conductor and the second electrical conductor by melting the low-melting-point alloy layer and flowing into the hole of the insulator. The electrical storage element of Claim 1. 2. The molten layer short-circuits the first electric conductor and the second electric conductor by melting the low-melting-point alloy layer and deforming part or all of the insulator. The electrical storage element of any one of 1-9. The electric storage element according to any one of claims 1 to 11, wherein the molten layer is formed by laminating the insulator and the low-melting-point alloy layer. A power storage element system comprising a power storage element group in which a plurality of power storage elements are connected in series and / or in parallel,
The power storage element system according to claim 1, wherein at least one of the plurality of power storage elements is the power storage element according to claim 1.

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