Power storage device

Abstract

To provide a power storage device which can prevent gas leakage between a power storage element and an exhaust duct by using a simple configuration.SOLUTION: A power storage device 1 comprises: a power storage element 100 having a container 110; and an exhaust duct 40. The power storage element 100 has a gas exhaust part 115 disposed on a lid plate 112 which serves as a wall part of the container 110. The gas exhaust part 115 has a cylindrical part 116 and a valve part 117. With part of the lid plate 112 formed in a manner protruding to the outside of the container 110, the cylindrical part 116 is provided integrally with the lid plate 112. The cylindrical part forms a gas passage which communicates with the inside of the container 110. The valve part 117 is disposed on the cylindrical part 116 so as to close the gas passage. The exhaust duct 40 has an insertion hole 44 penetrating through a duct wall part 42a which divides the inside of the exhaust duct 40 from the outside thereof. The cylindrical part 116 is inserted into the insertion hole 44.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device including an electricity storage element. [Background technology]

[0002] Patent Document 1 discloses a power supply device that includes a battery cell with a gas exhaust valve and a gas duct for guiding gas exhausted from the gas exhaust valve to an external gas exhaust path. The gas duct includes a connecting opening that communicates with the gas exhaust valve and a duct outlet that connects to the gas exhaust path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 024433 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional power supply device (electricity storage device) described above, a duct (exhaust duct) opening is provided at a position facing the gas exhaust valve of each of the multiple battery cells (electricity storage elements), and a packing (gasket) is disposed between the periphery of the gas exhaust valve and the periphery of the exhaust duct opening. The gasket is formed, for example, from a highly flexible material such as rubber, thereby ensuring airtightness in the gas flow path connecting the gas exhaust valve and the exhaust duct opening. However, when the gas exhaust valve of the energy storage element is opened, the gas ejected from the gas exhaust valve is at a high temperature, for example, above 400°C. This may cause, for example, a portion of the gasket to melt and gas to leak from the melted location. Such gas leakage from an unexpected location may damage the exterior of the energy storage device or other components near the energy storage device. Furthermore, when arranging the exhaust duct for the multiple energy storage elements, the gasket must be positioned precisely, which increases the number of parts, complicates the assembly procedure, and increases manufacturing costs.

[0005] The present invention was made by the inventor of the present application with a new focus on the above-mentioned problem, and aims to provide an energy storage device that has a simple configuration and can suppress gas leakage between the energy storage element and the exhaust duct. [Means for solving the problem]

[0006] A storage device according to one aspect of the present invention is a storage device comprising a storage element having a container and an exhaust duct, wherein the storage element has a gas exhaust section arranged on a wall of the container, the gas exhaust section being a cylindrical section integrally formed on the wall by forming a part of the wall section so as to protrude towards the outside of the container, the cylindrical section forming a gas flow path communicating with the inside of the container, and a valve section arranged on the cylindrical section to block the gas flow path, and the exhaust duct has an insertion hole penetrating a duct wall section separating the inside and outside of the exhaust duct, into which the cylindrical section is inserted.

[0007] According to this configuration, when the valve of the gas discharge unit opens due to an increase in the internal pressure of the energy storage element container, the gas inside the container is efficiently delivered to the exhaust duct via the tubular portion. Specifically, gas can be delivered to the inside of the exhaust duct while suppressing gas leakage between the gas discharge unit and the exhaust duct without interposing a sealing member such as a gasket between the gas discharge unit and the exhaust duct. Furthermore, because the tubular portion is integral with the wall portion, there is no seam between these components, which would occur, for example, if the tubular portion and the wall portion were separate. Therefore, gas does not leak from the seam between the tubular portion and the wall portion. In this way, the energy storage device according to this aspect can suppress gas leakage between the energy storage element and the exhaust duct with a simple configuration.

[0008] The cylindrical portion of the gas discharge portion may be formed in a frustum shape with a base on the wall side.

[0009] With this configuration, the cylindrical portion is formed so that the opening area decreases toward the tip, which is the end in the protruding direction, thereby suppressing the spread of gas discharged from the end opening of the cylindrical portion and, as a result, more reliably sending the gas discharged from the gas discharge portion into the inside of the exhaust duct.

[0010] The inner circumferential surface of the insertion hole of the exhaust duct may be tapered to fit the outer circumferential surface of the cylindrical portion.

[0011] With this configuration, since the cylindrical portion and the insertion hole have corresponding shapes, the occurrence of gaps between the cylindrical portion and the insertion hole is more reliably suppressed, thereby more reliably suppressing gas leakage through the gaps.

[0012] The cylindrical portion may be formed in a truncated cone shape, and the insertion hole may be formed in a circular shape having an inner diameter equal to or smaller than a maximum outer diameter of the cylindrical portion.

[0013] With this configuration, the cylindrical portion has a truncated cone shape and the insertion hole has a circular shape, which makes it easy to form the cylindrical portion and the insertion hole of corresponding sizes. Furthermore, the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the insertion hole can be in contact with each other at least along a line. This more reliably prevents gas leakage between the energy storage device and the exhaust duct.

[0014] The cylindrical portion may be formed to a size such that a tip of the cylindrical portion protrudes into the exhaust duct when inserted into the insertion hole.

[0015] With this configuration, when the valve is opened, the gas in the container is reliably guided to the inside of the exhaust duct by the cylindrical portion, thereby more reliably preventing gas from leaking between the energy storage device and the exhaust duct. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an electricity storage device that can suppress gas leakage between the electricity storage element and the exhaust duct with a simple configuration. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view showing the appearance of a power storage device according to an embodiment; [Figure 2] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. [Figure 3] FIG. 2 is a perspective view of an energy storage element included in the energy storage device according to the embodiment. [Figure 4] FIG. 2 is an exploded perspective view showing the structural relationship between an exhaust duct and an energy storage element unit according to the embodiment. [Figure 5] 3 is a first partial cross-sectional view showing the structural relationship between an exhaust duct and an energy storage element according to the embodiment. FIG. [Figure 6] 10 is a second partial cross-sectional view showing the structural relationship between the exhaust duct and the energy storage element according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including its modified examples). Note that the embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, in each drawing, dimensions and the like are not strictly illustrated. Furthermore, in each drawing, the same or similar components are assigned the same reference numerals.

[0019] In the following description and drawings, the longitudinal direction of the exterior body of the energy storage device, the arrangement direction of multiple energy storage elements, or the opposing direction of the long side surfaces of the containers of the energy storage elements is defined as the Y-axis direction. The lateral direction of the exterior body of the energy storage device, the opposing direction of the short side surfaces of the containers of the energy storage elements, or the arrangement direction of a pair of electrode terminals of one energy storage element is defined as the X-axis direction. The arrangement direction of the main body and lid of the exterior body of the energy storage device, or the up-down direction is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the mode of use, the Z-axis may not be the up-down direction; however, for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0020] In the following description, for example, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis. Furthermore, simply referring to the "X-axis direction" means either or both directions parallel to the X-axis. The same applies to terms related to the Y-axis and Z-axis.

[0021] Furthermore, expressions indicating relative directions or attitudes, such as "parallel" and "orthogonal," also include cases where the directions or attitudes are not strictly those. For example, "two directions are orthogonal" does not only mean that the two directions are completely orthogonal, but also means that the two directions are substantially orthogonal, i.e., there is a difference of, for example, a few percent.

[0022] (Embodiment) [1. General description of the power storage device] First, a schematic configuration of an energy storage device 1 according to the present embodiment will be described. FIG. 1 is a perspective view showing the exterior of the energy storage device 1 according to the embodiment. FIG. 2 is an exploded perspective view of the energy storage device 1 according to the embodiment. FIG. 3 is a perspective view of an energy storage element 100 provided in the energy storage device 1 according to the embodiment. In addition to the components shown in FIG. 2 and subsequent figures, the exterior body 10 may house bus bars, electrical equipment, etc., and may further contain spacers arranged along the energy storage elements 100, restraining members that restrain the plurality of energy storage elements 100, etc. However, illustration and description of these components will be omitted as appropriate.

[0023] The power storage device 1 is a device that can charge with electricity from an external source and discharge electricity to the outside, and in this embodiment has a substantially rectangular parallelepiped shape. The power storage device 1 is, for example, a battery module (battery assembly) used for power storage or power supply purposes. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline-powered vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0024] 1 and 2, the energy storage device 1 includes an exterior body 10, and an energy storage element unit 90 and an exhaust duct 40 housed in the exterior body 10. The exterior body 10 is a box-shaped (substantially rectangular parallelepiped) container (module case) that forms the housing of the energy storage device 1. In other words, the exterior body 10 is disposed outside the energy storage element unit 90 and the exhaust duct 40, fixes the energy storage element unit 90 and the exhaust duct 40 in predetermined positions, and protects them from impacts and the like. The exterior body 10 is formed from an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, or from a metal or the like with an insulating coating. This prevents the energy storage element unit 90 and the like from coming into contact with external metal members and the like. Note that the exterior body 10 may be formed from a conductive material such as a metal as long as electrical insulation is maintained between the exterior body 10 and the energy storage element unit 90 and the like.

[0025] The exterior body 10 has an exterior body main body 12 that constitutes the main body of the exterior body 10, and a lid body 11. The exterior body main body 12 is a rectangular cylindrical housing with a bottom and an opening 12a formed on the positive side of the Z axis, and houses the energy storage element unit 90 and the exhaust duct 40.

[0026] The lid 11 is a rectangular member that closes the opening 12a of the exterior body main body 12. The lid 11 is joined to the exterior body main body 12 by adhesive, heat sealing, ultrasonic welding, or fastening with bolts and nuts. A pair of external terminals 13, which are a pair of module terminals (general terminals) on the positive and negative sides, are arranged on the lid 11. The energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via the pair of external terminals 13. The external terminals 13 are formed of a conductive metal member such as aluminum, an aluminum alloy, copper, or a copper alloy. In this embodiment, the lid 11 has an exhaust port 15, into which the duct opening 40a of the exhaust duct 40 is inserted, at its end on the negative side of the Y-axis. The position of the exhaust port 15 is not limited to this position. For example, the exhaust port 15 may be provided at the end (the end on the positive side of the Y-axis) opposite to the end of the lid 11 where the external terminals 13 are arranged (see FIG. 1). In this case, the duct opening 40a is provided at the end of the exhaust duct 40 on the positive side of the Y axis, and is inserted into the exhaust port 15.

[0027] The energy storage element unit 90 is a group of energy storage elements 100 composed of one or more energy storage elements 100. The energy storage element unit 90 according to this embodiment is composed of eight energy storage elements 100, and the eight energy storage elements 100 are arranged in the Y-axis direction with their long side surfaces 110a facing the Y-axis direction. The energy storage element unit 90 may include a spacer (not shown) disposed between adjacent energy storage elements 100, or may include a restraining member (not shown) that restrains the plurality of energy storage elements 100. The eight energy storage elements 100 included in the energy storage element unit 90 are connected in series, for example, by a plurality of bus bars (not shown). The electrical connection mode of the eight energy storage elements 100 is not limited thereto. For example, four energy storage element 100 groups, each consisting of two energy storage elements 100 connected in parallel, may be formed, and these four energy storage element 100 groups may be connected in series using a plurality of bus bars.

[0028] The energy storage element 100 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. As shown in FIG. 3 , the energy storage element 100 includes a flat rectangular (square) container 110, an electrode assembly housed in the container 110, a current collector, an electrolyte, and the like. For example, a wound-type electrode assembly formed by winding a layered arrangement of a positive electrode plate and a negative electrode plate with a separator sandwiched between them is used as the electrode assembly. Examples of the electrode assembly included in the energy storage element 100 include a wound-type electrode assembly, a stack-type electrode assembly formed by stacking multiple flat electrode plates, and a bellows-type electrode assembly in which electrode plates are folded in a bellows shape. There are no particular limitations on the type of electrolyte housed in the container 110, and various types can be selected as long as they do not impair the performance of the energy storage element 100. The energy storage element 100 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 100 may not be a secondary battery, but may be a primary battery that allows stored electricity to be used without the user having to charge it. The energy storage element 100 may also be a battery that uses a solid electrolyte. The shape of the energy storage element 100 is not limited to the above-mentioned rectangular shape, but may be other shapes such as a polygonal prism, a cylindrical shape, an elliptical cylindrical shape, or an oblong cylindrical shape.

[0029] In this embodiment, the container 110 is a rectangular parallelepiped case having a container body 111 that houses an electrode assembly and the like, and a cover plate 112 that closes the opening of the container body 111. As shown in FIG. 3 , the container body 111 has a pair of long sides 110a and a pair of short sides 110b. The cover plate 112 is an example of a wall portion of the container 110 in this embodiment, and is a rectangular plate-like member that is elongated in the X-axis direction. The cover plate 112 is disposed in a position that closes the opening of the container body 111. A pair of electrode terminals 120 is disposed on the cover plate 112, and a gas exhaust portion 115 is provided between the pair of electrode terminals 120. In this embodiment, the gas exhaust portion 115 has a cylindrical portion 116 that forms a gas flow path that communicates with the interior of the container 110, and a valve portion 117 that is disposed in the cylindrical portion 116 and closes the gas flow path. When the internal pressure of container 110 rises excessively, gas discharge portion 115 opens as valve portion 117 breaks under the internal pressure, thereby discharging the gas inside container 110 to the outside through cylindrical portion 116. Note that in FIG. 3 and other figures, valve portion 117 is shown as a simple flat plate-like portion, but specifically, valve portion 117 is provided on cover plate 112 as a thin-walled portion so as to be easily broken by the internal pressure of container 110. Furthermore, valve portion 117 may be provided with a groove so as to be easily broken by the internal pressure.

[0030] The container 110 having such a configuration has a structure in which the inside can be sealed by, after the electrode body and the like are housed inside the container body 111, welding the container body 111 to the cover plate 112. The materials of the container body 111 and the cover plate 112 are not particularly limited, but are preferably weldable metals such as stainless steel, aluminum, aluminum alloy, iron, and plated steel sheet.

[0031] The electrode terminal 120 is a terminal member electrically connected to the electrode assembly housed in the container 110 and is fixed to the cover plate 112. One of the pair of electrode terminals 120 is electrically connected to the positive electrode of the electrode assembly, and the other is electrically connected to the negative electrode of the electrode assembly. In this embodiment, the electrode terminal 120 is a bolt terminal having a shaft with a thread formed on its outer circumferential surface, and a bus bar is fastened to the electrode terminal 120 by the shaft and a nut (not shown). The electrode terminal 120 is not limited to a bolt terminal and may be a terminal having a flat joining surface to which a bus bar is joined by welding, for example. The electrode terminal 120 is formed of a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0032] The plurality of energy storage elements 100 configured in this manner are aligned in the Y-axis direction with their respective cover plates 112 facing upward (positive Z-axis direction). As a result, the gas discharge sections 115 of the plurality of energy storage elements 100 face upward (positive Z-axis direction) and are aligned in the Y-axis direction. An exhaust duct 40 is provided at a position where the plurality of gas discharge sections 115 face each other. When gas is discharged from any of the gas discharge sections 115, the gas passes through the inside of the exhaust duct 40 and is discharged to the outside of the exterior body 10 through a duct opening 40a inserted into the exhaust port 15 of the exterior body 10.

[0033] In the energy storage device 1 configured in this manner, the connection between the gas discharge section 115 of the energy storage element 100 and the exhaust duct 40 has a structure for suppressing gas leakage. Hereinafter, the configuration of the exhaust duct 40 and its surroundings in the energy storage device 1 according to this embodiment will be described with reference to Figs.

[0034] [2. Exhaust duct and surrounding structure] FIG. 4 is an exploded perspective view showing the structural relationship between an exhaust duct 40 and an energy storage element unit 90 according to the embodiment. FIG. 5 is a first partial cross-sectional view showing the structural relationship between an exhaust duct 40 and an energy storage element 100 according to the embodiment. FIG. 6 is a second partial cross-sectional view showing the structural relationship between an exhaust duct 40 and an energy storage element 100 according to the embodiment. FIGS. 5 and 6 show cross sections of the exhaust duct 40 and the energy storage element 100 in a YZ plane passing through line VV in FIG. 4. FIG. 5 illustrates the exhaust duct 40 and the energy storage element 100 in a separated state, while FIG. 6 illustrates the exhaust duct 40 and the energy storage element 100 in an assembled state. Also, FIGS. 5 and 6 simply illustrate a wound electrode body 200 housed in a container body 111 of the energy storage element 100.

[0035] 4, in this embodiment, the plurality of energy storage elements 100 forming the energy storage element unit 90 are aligned in the Y-axis direction, and each of the plurality of energy storage elements 100 has a gas discharge portion 115 protruding in the positive direction of the Z-axis at the center in the X-axis direction. As a result, the plurality of gas discharge portions 115 are arranged in a line in the Y-axis direction at the center in the X-axis direction of the energy storage element unit 90. An exhaust duct 40 is arranged at a position facing these plurality of gas discharge portions 115.

[0036] As shown in FIG. 4 , exhaust duct 40 has a duct wall 42a that separates the inside and outside of exhaust duct 40 at a position facing energy storage element unit 90, and duct wall 42a has a plurality of insertion holes 44 formed therein. As shown in FIGS. 5 and 6 , each of the plurality of insertion holes 44 is a hole into which a gas discharge portion 115 of an energy storage element 100 is inserted. When valve portion 117 of gas discharge portion 115 is opened, gas discharged from gas discharge portion 115 flows into exhaust duct 40 and is discharged to the outside of exterior body 10 from duct opening 40a at the end of exhaust duct 40 on the negative Y-axis direction side. At this time, gas discharge portion 115, which is formed in a convex shape toward exhaust duct 40, is inserted into insertion hole 44 of duct wall 42a, and therefore gas can be efficiently sent into exhaust duct 40.

[0037] More specifically, in this embodiment, exhaust duct 40 has a lower member 42 having duct wall portion 42a, and an upper member 41 that covers lower member 42 from above. As shown in Fig. 4, lower member 42 has a shape that is open at both ends in the Y-axis direction. In this embodiment, upper member 41 has a shape such that the end in the positive Y-axis direction closes that end of exhaust duct 40, and the end in the negative Y-axis direction is open. In other words, a duct opening 40a, which is an outlet for gas from the inside to the outside of exhaust duct 40, is provided at the end in the negative Y-axis direction of exhaust duct 40.

[0038] In the exhaust duct 40, the upper member 41, which forms the upper wall portion facing the insertion hole 44, is made of a metal such as aluminum or iron. This allows the upper member 41, which the gas directly impinges on, to have the strength and heat resistance to withstand the heat and pressure of the gas discharged from the gas discharge section 115 inserted into the insertion hole 44. The lower member 42 is made of a highly heat-resistant resin such as PPS. This allows the insertion hole 44 to be easily formed in the lower member 42 with a size and shape corresponding to the size and shape of the gas discharge section 115. The materials of the upper member 41 and the lower member 42 are not limited to these examples. For example, the lower member 42 may be made of a metal such as aluminum or iron. In this case, an insulating member is disposed between the lower member 42 and the plurality of energy storage elements 100 to electrically insulate them from each other. Examples of the insulating member include a resin insulating sheet or a resin coating formed on the lower surface of the lower member 42. Alternatively, the upper member 41 may be made of resin, and a metal plate may be disposed at a position facing the insertion hole 44 in the upper member 41 to protect the upper member 41 from the heat and pressure of the gas.

[0039] As described above, the energy storage device 1 according to this embodiment includes an energy storage element 100 having a container 110 and an exhaust duct 40. The energy storage element 100 has a gas exhaust portion 115 arranged on a cover plate 112, which is a wall portion of the container 110. The gas exhaust portion 115 has a cylindrical portion 116 and a valve portion 117. The cylindrical portion 116 is formed integrally with the cover plate 112 by forming a portion of the cover plate 112 so as to protrude toward the outside of the container 110, and forms a gas flow path that communicates with the inside of the container 110. The valve portion 117 is arranged in the cylindrical portion 116 and closes the gas flow path. The exhaust duct 40 has an insertion hole 44 that penetrates a duct wall portion 42a that separates the inside and outside of the exhaust duct 40. The cylindrical portion 116 is inserted into the insertion hole 44. Specifically, in this embodiment, valve portion 117 is disposed at the tip (top) of cylindrical portion 116 and is normally closed. However, if the internal pressure of container 110 rises excessively, valve portion 117 opens, thereby discharging gas from cylindrical portion 116. In this state, cylindrical portion 116 forms a gas flow path that communicates with the interior of container 110.

[0040] According to this configuration, when the valve portion 117 of the gas discharge portion 115 opens due to an increase in the internal pressure of the container 110 of the energy storage device 100, the gas inside the container 110 is efficiently sent to the exhaust duct 40 via the tubular portion 116. Specifically, the gas can be sent into the exhaust duct 40 while suppressing gas leakage between the gas discharge portion 115 and the exhaust duct 40 without interposing a sealing member such as a gasket between the gas discharge portion 115 and the exhaust duct 40. In other words, the gas discharged from the energy storage device 100 is efficiently sent into the exhaust duct 40 by the tubular portion 116 without causing the sealing member to melt due to the heat of the gas discharged from the gas discharge portion 115, resulting in gas leakage. Furthermore, because the tubular portion 116 is provided integrally with the cover plate 112, there is no seam between these members, which would occur if the tubular portion 116 and the cover plate 112 were separate members, for example. Therefore, gas does not leak from the joint between the cylindrical portion 116 and the cover plate 112. In this way, the energy storage device according to this embodiment can suppress gas leakage between the energy storage element 100 and the exhaust duct 40 with a simple configuration.

[0041] Furthermore, gas discharge portion 115, which protrudes from container 110 to efficiently guide gas into exhaust duct 40, is inserted into insertion hole 44 in duct wall portion 42a, and duct wall portion 42a is therefore positioned close to cover plate 112. In other words, at least a portion of the length of protrusion of gas discharge portion 115 from container 110 is absorbed by the thickness of duct wall portion 42a. This allows exhaust duct 40 to be positioned close to energy storage devices 100. Therefore, when exhaust duct 40 is positioned above energy storage devices 100, the height from the bottom surface of energy storage devices 100 to the top surface of exhaust duct 40 can be made relatively small. This is advantageous for reducing the size and height of energy storage device 1.

[0042] 4 to 6, the cylindrical portion 116 of the gas discharge portion 115 is formed in a frustum shape with its base on the cover plate 112 side.

[0043] That is, cylindrical portion 116 is formed so that the opening area becomes smaller toward the tip, which is the end in the protruding direction. Therefore, when valve portion 117 is opened, the spread of gas discharged from the end opening of cylindrical portion 116 is suppressed, and as a result, gas discharged from gas discharge portion 115 is sent into exhaust duct 40 more reliably.

[0044] Furthermore, with respect to the cylindrical portion 116 having a frustum shape as described above, the insertion hole 44 of the exhaust duct 40, into which the cylindrical portion 116 is inserted, has a shape that corresponds to the shape of the cylindrical portion 116. Specifically, in this embodiment, as shown in Figures 5 and 6, for example, the inner circumferential surface 44a of the insertion hole 44 of the exhaust duct 40 is formed in a tapered shape that follows the outer circumferential surface of the cylindrical portion 116. In other words, as shown in Figure 5, for example, the outer circumferential surface of the cylindrical portion 116 is inclined with respect to the axial direction (Z-axis direction) of the cylindrical portion 116, and the inner circumferential surface 44a of the insertion hole 44 is also inclined along this outer circumferential surface.

[0045] Thus, since the cylindrical portion 116 and the insertion hole 44 have corresponding shapes, the generation of a gap between the cylindrical portion 116 and the insertion hole 44 is more reliably suppressed, and thereby, the leakage of gas through the gap is more reliably suppressed.

[0046] Further, in the present embodiment, the cylindrical portion 116 is formed in a frustum of a cone shape, and the insertion hole 44 is formed in a circular shape having an inner diameter equal to or less than the maximum outer diameter of the cylindrical portion 116. Specifically, as shown in FIG. 5, when the maximum outer diameter of the frustum of a cone-shaped cylindrical portion 116 is Dc, and the minimum inner diameter and the maximum inner diameter of the circular insertion hole 44 into which the cylindrical portion 116 is inserted are Da and Db, respectively, Da < Db ≦ Dc. Therefore, when the cylindrical portion 116 is inserted into the insertion hole 44, at least one of the inner peripheral surfaces 44a at the position of the maximum inner diameter Db and the position of the minimum inner diameter Da of the insertion hole 44 contacts the outer peripheral surface of the cylindrical portion 116.

[0047] Thus, in the present embodiment, the cylindrical portion 116 is in a frustum of a cone shape, and the insertion hole 44 is in a circular shape, that is, both the cylindrical portion 116 and the insertion hole 44 are based on a circular (true circle) shape. Therefore, it is easy to form the cylindrical portion 116 and the insertion hole 44 having corresponding sizes, and the outer peripheral surface of the cylindrical portion 116 and the inner peripheral surface 44a of the insertion hole 44 can be brought into contact at least in a line. Thereby, the leakage of gas between the power storage element 100 and the exhaust duct 40 can be more reliably suppressed.

[0048] Note that the specific shape of the cylindrical portion 116 when the cylindrical portion 116 is in a frustum shape is not limited to a frustum of a cone shape in which the outer shape in a plan view (viewed from the +Z axis direction) is circular. The cylindrical portion 116 may be, for example, a frustum of a pyramid shape in which the outer shape in a plan view is polygonal, or a frustum of an elliptical cone shape in which the outer shape in a plan view is elliptical (excluding a circular shape). In any case, if the insertion hole 44 is a hole having a shape similar to the outer shape of the cylindrical portion 116 in a plan view and having a size equal to or less than the outer shape (similarity ratio of 1 or less), the outer peripheral surface of the cylindrical portion 116 and the inner peripheral surface 44a of the insertion hole 44 can be brought into contact at least in a line.

[0049] Also, focusing on the relationship between the protruding length of the cylindrical portion 116 and the length of the insertion hole 44 in its protruding direction (the depth of the insertion hole 44), the following can be said. That is, the cylindrical portion 116 is formed in a size such that the tip of the cylindrical portion 116 protrudes into the exhaust duct 40 when inserted into the insertion hole 44. Specifically, as shown in FIG. 5, if the protruding length of the cylindrical portion 116 of the gas discharge portion 115 from the container 110 (the height in the Z-axis direction from the edge of the cover plate 112 in the present embodiment) is Tc, and the length of the insertion hole 44 in the Z-axis direction is Tb, then Tb < Tc. As a result, as shown in FIG. 6, when substantially the entire portion from the tip of the cylindrical portion 116 to Tc is inserted into the insertion hole 44, the tip of the cylindrical portion 116 is exposed to the inside of the exhaust duct 40 from the insertion hole 44. Therefore, when the valve portion 117 is opened, the gas in the container 110 is surely guided to the inside of the exhaust duct 40 by the cylindrical portion 116. As a result, gas leakage between the power storage element 100 and the exhaust duct 40 can be more surely suppressed.

[0050] Further, in the present embodiment, more specifically, a thin portion having a thickness of Tb (Tb < Ta) is formed in the duct wall portion 42a having a thickness of Ta, and the insertion hole 44 is formed in the thin portion. Thereby, while ensuring the rigidity or heat resistance of the duct wall portion 42a by making the wall thickness relatively thick, an insertion hole 44 having a depth at which the tip of the cylindrical portion 116 (gas discharge portion 115) can be exposed can be provided. In other words, even when the protruding length of the cylindrical portion 116 from the container 110 is smaller than the thickness of the duct wall portion 42a, an insertion hole 44 having a depth (length in the Z-axis direction) at which the tip of the cylindrical portion 116 protrudes into the exhaust duct 40 can be formed.

[0051] [3. Modified Example] As described above, the power storage device 1 according to the embodiment of the present invention has been described. However, the present invention is not limited to this embodiment. That is, the embodiment disclosed this time is illustrative in all respects and not restrictive, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0052] For example, the position of duct opening 40a, which serves as a gas outlet in exhaust duct 40, does not have to be the end of exhaust duct 40 in the main gas flow direction (Y-axis direction). For example, a position other than the end of exhaust duct 40 in the Y-axis direction that is convenient in relation to the destination of the gas discharged from power storage device 1 may be determined as the arrangement position of duct opening 40a. Furthermore, multiple duct openings 40a may be provided in exhaust duct 40. For example, duct openings 40a may be provided at both ends of exhaust duct 40 in the Y-axis direction.

[0053] Furthermore, exhaust duct 40 does not necessarily have to be formed by combining lower member 42 and upper member 41. For example, a metal plate having a plurality of insertion holes 44 formed therein may be bent to produce a metal square tube having a plurality of insertion holes 44 arranged in the longitudinal direction of one surface, and the square tube may be used as exhaust duct 40.

[0054] Furthermore, in the container 110, the wall portion on which the gas exhaust portion 115 is provided does not have to be the cover plate 112. For example, the gas exhaust portion 115 may be provided on the wall portion that forms the short side surface 110b (see FIG. 3) of the container body 111. Even in this case, by each of the multiple energy storage elements 100 included in the energy storage element unit 90 having the gas exhaust portion 115 on the short side surface 110b, it is possible to arrange one exhaust duct 40 corresponding to these multiple gas exhaust portions 115.

[0055] Furthermore, cylindrical portion 116 does not necessarily have to be frustum-shaped, and may have a cylindrical shape whose inner and outer diameters are constant in the axial direction (the Z-axis direction in the embodiment). Furthermore, although valve portion 117 is provided at the tip of cylindrical portion 116 in the embodiment, it may be located at any position in the axial direction of cylindrical portion 116. Furthermore, valve portion 117 does not need to be provided integrally with cover plate 112 and cylindrical portion 116, and for example, a circular metal plate separate from cylindrical portion 116 may be joined to cylindrical portion 116 by welding.

[0056] Furthermore, the exhaust duct 40 may be provided in the energy storage device 1 as a part of another member. For example, if a bus bar holder that holds a bus bar (not shown) is arranged above the energy storage element unit 90, the exhaust duct may be formed by a part of the bus bar holder. Furthermore, if an inner lid is arranged to cover the energy storage element unit 90 from above, the exhaust duct may be formed by a part of the inner lid. In other words, if another member is arranged on the side of the energy storage element unit 90 from which the multiple gas discharge portions 115 protrude, exhaust ducts corresponding to the multiple energy storage elements 100 of the energy storage element unit 90 may be provided as a part of the other member. This prevents an increase in the number of parts in the energy storage device 1.

[0057] Furthermore, exhaust duct 40 does not need to be formed in a box shape as shown in FIG. 2, but may be formed, for example, in a dome shape with a raised central portion in the X-axis direction and an elongated dome shape in the Y-axis direction.

[0058] Furthermore, configurations constructed by arbitrarily combining the components included in the above-described embodiments and their modifications are also included within the scope of the present invention. [Industrial Applicability]

[0059] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0060] 1. Energy storage device 10. Exterior body 11 Lid 12. Exterior body 12a opening 13 External terminal 15 exhaust port 40 Exhaust duct 40a Duct opening 41 Upper member 42 Lower member 42a Duct wall 44 Insertion hole 44a Inner surface 90 Energy storage element unit 100 Energy storage element 110 Container 110a long side 110b short side 111 Container body 112 Lid plate 115 Gas exhaust section 116 Cylindrical part 117 Valve section 120 Electrode terminal 200 Electrode body

Claims

1. An electricity storage device including an electricity storage element having a container and an exhaust duct, the energy storage element has a gas exhaust portion disposed on a wall portion of the container, The gas exhaust section a cylindrical portion that is integrally formed with the wall portion by forming a portion of the wall portion protruding toward the outside of the container, the cylindrical portion forming a gas flow path that communicates with the inside of the container; a valve portion disposed in the cylindrical portion and configured to close the gas flow path, the exhaust duct has an insertion hole penetrating a duct wall portion that separates the inside and outside of the exhaust duct, the insertion hole into which the cylindrical portion is inserted; the insertion hole is a hole having a shape similar to the outer shape of the cylindrical portion when viewed from the protruding direction of the cylindrical portion, and an outer peripheral surface of the cylindrical portion and an inner peripheral surface of the insertion hole are in contact with each other at least along a line; The cylindrical portion of the gas discharge portion is formed in a frustum shape having a base on the wall portion side. Energy storage device.

2. A power storage device comprising a power storage element having a container and an exhaust duct, the energy storage element has a gas exhaust portion disposed on a wall portion of the container, The gas exhaust section a cylindrical portion that is integrally formed with the wall portion by forming a portion of the wall portion protruding toward the outside of the container, the cylindrical portion forming a gas flow path that communicates with the inside of the container; a valve portion disposed in the cylindrical portion and configured to close the gas flow path, The exhaust duct has an insertion hole penetrating a duct wall portion that separates the inside and outside of the exhaust duct, and the insertion hole into which the cylindrical portion is inserted. the cylindrical portion of the gas discharge portion is formed in a frustum shape having a base on the wall portion side, The inner circumferential surface of the insertion hole of the exhaust duct is formed in a tapered shape along the outer circumferential surface of the cylindrical portion. Energy storage device.

3. The cylindrical portion is formed in a truncated cone shape, The insertion hole is formed in a circular shape having an inner diameter equal to or smaller than the maximum outer diameter of the cylindrical portion. The electricity storage device according to claim 1 or 2.

4. The cylindrical portion is formed to have a size such that a tip of the cylindrical portion protrudes into the exhaust duct when inserted into the insertion hole. The electricity storage device according to any one of claims 1 to 3.

5. The exhaust duct has a plurality of the insertion holes aligned in the longitudinal direction of the duct wall portion, A plurality of the energy storage elements are arranged in the longitudinal direction, The cylindrical portions of the plurality of energy storage elements are inserted into the plurality of insertion holes. The electricity storage device according to any one of claims 1 to 4.

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