Valve structure and power storage device

Abstract

A valve structure (10) comprises: a passage (20A) that causes the inside and outside of a container (70A), which accommodates a power storage device element (100), to communicate; and a reservoir (30) that is positioned within the passage, and is for accumulating a liquid (200) through which a gas generated from the power storage device element can pass.

Description

[Technical Field]

[0001] The present invention relates to a valve structure and an electricity storage device including the same. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2016-31934 (Patent Document 1) discloses a battery in which a battery element is housed in a pouch. The pouch has a valve structure with a check valve attached to a heat-sealed portion formed along its periphery. This check valve is configured to activate and release gas when the internal pressure of the pouch rises above a certain level.

[0003] Furthermore, Japanese Patent Laid-Open Publication No. 2010-153841 (Patent Document 2) discloses a battery in which a battery element is housed in a box-shaped laminated container. This laminated container has a flange-shaped heat-sealed portion formed along its periphery, which has a portion (hereinafter referred to as an easy-peel portion) that is easier to peel than other portions. The easy-peel portion peels when the internal pressure of the laminated container rises above a certain level, and gas is released through a hole formed in the center of the easy-peel portion. Unlike the check valve in Patent Document 1, the easy-peel portion is a breakable valve that does not return to its original state once peeled. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-31934 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-153841 Summary of the Invention [Problem to be solved by the invention]

[0005] A check valve is generally a one-way valve designed to prevent backflow. However, in a battery such as that described in Patent Document 1, even a small amount of moisture from the atmosphere entering the pouch can cause battery degradation, so backflow prevention must be performed with greater precision. Therefore, it is practically difficult for a check valve that vents gas from the pouch described in Patent Document 1 to completely prevent the entry of air into the pouch to the high level required for a battery. Therefore, a battery such as that described in Patent Document 1 faces the problem of moisture from the atmosphere entering the pouch, causing battery degradation.

[0006] On the other hand, in a battery such as that in Patent Document 2, once the rupture valve is ruptured, air enters the laminated container through the passage formed by the rupture. Therefore, even when a rupture valve is used as in Patent Document 2, there is a problem in that moisture contained in the air enters the laminated container, causing deterioration of the battery.

[0007] An object of the present invention is to provide a valve structure that can prevent moisture from entering a container that houses an electricity storage device element, and an electricity storage device including the valve structure. [Means for solving the problem]

[0008] A valve structure according to a first aspect of the present invention comprises a passage that connects the inside and outside of a container that houses an electricity storage device element, and a liquid reservoir portion located within the passage that stores a liquid through which gas generated from the electricity storage device element can pass.

[0009] A valve structure according to a second aspect of the present invention is the valve structure according to the first aspect, wherein the passage includes an opening for discharging the gas to the outside of the container, and the liquid reservoir is located at a position away from the opening on the inside of the container.

[0010] A valve structure according to a third aspect of the present invention is the valve structure according to the first or second aspect, and has a valve outer body in which the passage is formed, and the valve outer body includes an attachment portion that is fixed to the container.

[0011] A valve structure according to a fourth aspect of the present invention is the valve structure according to the third aspect, wherein the valve outer body further includes a tubular portion connected to the mounting portion and disposed outside the container, the tubular portion including a curved portion, and the liquid reservoir portion being located in the curved portion.

[0012] A valve structure according to a fifth aspect of the present invention is the valve structure according to the third aspect, wherein the valve outer body further includes a tubular portion connected to the mounting portion and a housing into which the tubular portion is inserted, and the liquid reservoir portion is located within the housing.

[0013] A valve structure according to a sixth aspect of the present invention is the valve structure according to the third or fourth aspect, wherein the liquid reservoir further includes a partition member supported by the valve outer body and partitioning a storage space in the passage for storing the liquid.

[0014] A valve structure according to a seventh aspect of the present invention is the valve structure according to the sixth aspect, wherein the liquid reservoir includes a retaining member that is supported by at least one of the valve outer body and the partition member and is capable of retaining the liquid, and the material constituting the retaining member includes a porous material.

[0015] A valve structure according to an eighth aspect of the present invention is the valve structure according to the third aspect, wherein the valve outer body further includes a nozzle connected to the attachment portion and tapering toward the liquid reservoir portion.

[0016] A valve structure according to a ninth aspect of the present invention is the valve structure according to any one of the first to eighth aspects, further comprising a check valve that is arranged on the inner side of the container with respect to the liquid reservoir portion and opens when the internal pressure of the container increases due to the gas generated inside the container, thereby allowing the gas to pass from the inner side to the outer side of the container.

[0017] A valve structure according to a tenth aspect of the present invention is the valve structure according to any one of the first to ninth aspects, wherein the melting point of the liquid is 0° C. or lower.

[0018] A valve structure according to an eleventh aspect of the present invention is the valve structure according to any one of the first to tenth aspects, wherein the boiling point of the liquid is 150° C. or higher.

[0019] An electricity storage device according to a twelfth aspect of the present invention includes the valve structure according to any one of the first to eleventh aspects, and an internal space defined by the container and accommodating the electricity storage device element.

[0020] A thirteenth aspect of the present invention is an electric storage device according to the twelfth aspect that cites the first or second aspect, wherein the container includes a packaging material and a sealing portion where the packaging material is partially fused to form a storage space in which the electric storage device element is housed, and the passage is formed in a portion of the sealing portion where the packaging material is not fused. [Effects of the Invention]

[0021] According to the valve structure and the electricity storage device of the present invention, it is possible to prevent moisture from entering the container that houses the electricity storage device elements. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a plan view of an electricity accumulation device including a valve structure according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line D2-D2 in FIG. [Figure 3] FIG. 2 is a front view of the valve structure of FIG. 1. [Figure 4] FIG. 4 is a bottom view of the valve structure of FIG. 3 . [Figure 5] FIG. 6 is a cross-sectional view of a valve structure according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a valve structure according to a third embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a valve structure according to a fourth embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a valve structure according to a fifth embodiment. [Figure 9] FIG. 13 is a plan view of an electricity accumulation device according to a sixth embodiment. [Figure 10]FIG. 13 is a front view of a valve structure according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve structure according to an embodiment of the present invention and an electricity storage device including the valve structure will be described below with reference to the drawings.

[0024] [1. First embodiment] <1-1. Overall configuration of the electricity storage device> FIG. 1 shows a plan view of an electricity storage device 1 according to this embodiment. FIG. 2 is a cross-sectional view taken along line D2-D2 in FIG. 1. In these figures, parts that are not normally visible from the outside are partially shown with dotted lines for reference. Hereinafter, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 1 will be referred to as "front-back," the left-right direction will be referred to as "left-right," and the up-down direction in FIG. 2 will be referred to as "up-down." However, the orientation of the electricity storage device 1 during use is not limited to this.

[0025] The electricity storage device 1 includes a housing 70, an electricity storage device element 100, a tab 90A, and a tab film 90B. The housing 70 includes an internal space S1 and a peripheral seal portion 80. The electricity storage device element 100 is housed in the internal space S1 of the housing 70. One end of the tab 90A is joined to the electricity storage device element 100, and the other end protrudes outward from the peripheral seal portion 80 of the housing 70, with a portion of the space between the one end and the other end welded to the peripheral seal portion 80 via the tab film 90B.

[0026] The container 70 includes a container 70A. The container 70A is configured to include packaging materials 71 and 72. In a plan view, the packaging materials 71 and 72 are heat-sealed and fused together around the outer periphery of the container 70A, thereby forming a peripheral seal 80. The peripheral seal 80 forms an internal space S1 of the container 70A that is isolated from the external space. The peripheral seal 80 defines the periphery of the internal space S1 of the container 70A. Note that the heat sealing method used here may be heat welding from a heat source, ultrasonic welding, or the like. In any case, the peripheral seal 80 refers to the portion where the packaging materials 71 and 72 are fused and integrated. As shown in FIG. 2, the portion of the peripheral seal portion 80 that sandwiches the tab 90A and tab film 90B has the packaging material 72, the tab 90A, the pair of tab films 90B, and the packaging material 71 integrated together, and the portion of the peripheral seal portion 80 that sandwiches only the pair of tab films 90B has the packaging material 72, the pair of tab films 90B, and the packaging material 71 integrated together.

[0027] The packaging materials 71 and 72 are composed of, for example, a resin molded product or a film. The resin molded product referred to here can be manufactured by methods such as injection molding, pressure forming, vacuum forming, and blow molding, and in-mold molding may also be used to impart design and functionality. The resin may be polyolefin, polyester, nylon, ABS, or the like. The film referred to here refers to, for example, a resin film manufactured by methods such as inflation and T-die molding, or a resin film laminated on metal foil. The film referred to here may be stretched or unstretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, or may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

[0028] As described above, the packaging materials 71 and 72 can be configured in various ways, but in this embodiment, they are configured from laminate films. The laminate films can be laminates formed by laminating a base layer, a barrier layer, and a heat-sealable resin layer. The base layer functions as the base material for the packaging materials 71 and 72 and is typically an insulating resin layer that forms the outer layer of the container 70A. The barrier layer not only improves the strength of the packaging materials 71 and 72 but also functions to prevent at least moisture and the like from penetrating into the electricity storage device 1 and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin and forms the innermost layer of the container 70A.

[0029] The shape of the container 70A is not particularly limited and may be, for example, a bag (pouch). Examples of bag-like shapes include three-sided sealed, four-sided sealed, pillow-shaped, and gusseted. However, the container 70A of this embodiment has a shape as shown in FIGS. 1 and 2 and is manufactured by heat-sealing a tray-shaped packaging material 71 and a tray-shaped packaging material 72, which are also stacked on top of the packaging material 71, along their outer peripheries in a plan view. The packaging material 71 includes a rectangular annular flange portion 71B corresponding to the outer periphery in a plan view and a molded portion 71A that is continuous with the inner edge of the flange portion 71B and bulges downward therefrom. Similarly, the packaging material 72 includes a rectangular annular flange portion 72B corresponding to the outer periphery in a plan view and a molded portion 72A that is continuous with the inner edge of the flange portion 72B and bulges upward therefrom. The packaging materials 71 and 72 are stacked so that the respective molded portions 71A and 72A bulge in opposite directions. In this state, flange portion 71B of packaging material 71 and flange portion 72B of packaging material 72 are heat-sealed to be integrated, forming peripheral seal portion 80. Peripheral seal portion 80 extends around the entire outer periphery of container 70A and is formed in a rectangular ring shape. Note that one of packaging materials 71, 72 may be in sheet form.

[0030] The electricity storage device element 100 includes at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, an electricity storage member such as a lithium-ion battery (secondary battery) or a capacitor. When an abnormality occurs in the electricity storage device element 100, gas may be generated in the internal space S1 of the container 70A. When the electricity storage device 1 is a lithium-ion battery, gases such as volatile organic solvents, carbon monoxide, carbon dioxide, methane, ethane, hydrogen, and hydrogen fluoride may be generated in the internal space S1 of the container 70A due to volatilization of the organic solvent serving as the electrolyte and decomposition of the electrolytic solution. When the electricity storage device 1 is a capacitor, gas may be generated in the internal space S1 of the container 70A due to a chemical reaction in the capacitor. The electricity storage device 1 may also be an all-solid-state battery. In this case, the electricity storage device element 100 may include a solid electrolyte capable of generating gas. For example, when the solid electrolyte is sulfide-based, hydrogen sulfide gas may be generated.

[0031] The tabs 90A are metal terminals used for inputting and outputting power to and from the energy storage device element 100. The tabs 90A are arranged separately at the left and right ends of the peripheral seal portion 80 of the container 70A, one of which constitutes a positive electrode terminal and the other of which constitutes a negative electrode terminal. One left and right end of each tab 90A is electrically connected to an electrode (positive electrode or negative electrode) of the energy storage device element 100 in the internal space S1 of the container 70A, and the other end protrudes outward from the peripheral seal portion 80. The above-described configuration of the energy storage device 1 is particularly preferable for use in, for example, electric vehicles, hybrid vehicles, and other electric vehicles in which a large number of energy storage devices 1 are connected in series and used at high voltage. The attachment positions of the two tabs 90A constituting the positive and negative electrode terminals are not particularly limited, and they may be arranged, for example, on the same side of the peripheral seal portion 80.

[0032] The metal material constituting the tab 90A is, for example, aluminum, nickel, copper, etc. When the electricity storage device element 100 is a lithium ion battery, the tab 90A connected to the positive electrode is typically made of aluminum, etc., and the tab 90A connected to the negative electrode is typically made of copper, nickel, etc.

[0033] The left tab 90A is sandwiched between the packaging materials 71 and 72 at the left end of the peripheral seal portion 80 with a tab film 90B interposed therebetween. The right tab 90A is also sandwiched between the packaging materials 71 and 72 at the right end of the peripheral seal portion 80 with a tab film 90B interposed therebetween.

[0034] The tab film 90B is a so-called adhesive film and is configured to adhere to both the packaging materials 71, 72 and the tab 90A (metal). The tab film 90B can fix the tab 90A to the innermost layer (thermally adhesive resin layer) of the packaging materials 71, 72, even if they are made of different materials. The tab film 90B is previously welded and fixed to the tab 90A to be integrated, and the tab 90A with the tab film 90B fixed thereto is sandwiched between the packaging materials 71, 72 and welded to be integrated, as shown in FIG. 2.

[0035] When gas is generated in the internal space S1 of the container 70A as the electricity storage device 1 operates, the pressure in the internal space S1 gradually increases. If the pressure in the internal space S1 increases excessively, the container 70A may burst, damaging the electricity storage device 1. The housing 70 is provided with a valve structure 10 as a mechanism for preventing such an event. The valve structure 10 is a gas vent valve for adjusting the pressure in the internal space S1, and is attached to, for example, a peripheral seal portion 80 of the container 70A. The configuration of the valve structure 10 will be described in detail below.

[0036] <1-2. Valve structure configuration> Figure 3 is a front view of the valve structure 10. However, for reference, parts that are not normally visible from the outside are partially shown with dashed lines in Figure 3. The valve structure 10 has a valve outer body 20 having a passage 20A formed therein, as well as a liquid reservoir 30, a check valve 40, and a membrane filter 50 located within the passage 20A.

[0037] The material constituting the valve outer body 20 can be selected arbitrarily. The material constituting the valve outer body 20 is, for example, a metal or a synthetic resin. The metal is, for example, stainless steel or aluminum. The synthetic resin is, for example, an olefin. In this embodiment, the material constituting the valve outer body 20 is stainless steel. A passage 20A formed inside the valve outer body 20 is a passage that connects the inside and outside of the container 70A. The passage 20A has an opening 20AX that faces the internal space S1 of the container 70A and an opening 20AY that faces the external space.

[0038] The valve outer body 20 has an attachment portion 21, a connecting portion 22, a cylindrical portion 23, and a discharge portion 24. In this embodiment, the attachment portion 21, the connecting portion 22, the cylindrical portion 23, and the discharge portion 24 are arranged consecutively in this order in a direction from the inside to the outside of the container 70A.

[0039] The attachment portion 21 is a portion for attaching the valve structure 10 to the container 70A. The attachment portion 21 is attached by heat-sealing together with the packaging materials 71, 72 via the adhesive member 60 (see FIG. 1 ) when the container 70A is molded, specifically when the packaging materials 71, 72 are heat-sealed and fused to each other to form the peripheral seal portion 80. Alternatively, when the packaging materials 71, 72 are heat-sealed and fused to each other to form the peripheral seal portion 80, a portion that is not fused may be intentionally left unfused, and then the adhesive member 60 may be pre-fused and fixed to the attachment portion 21 to form an integrated portion. The attachment portion 21 with the adhesive member 60 may then be inserted into the unfused portion and heat-sealed between the packaging materials 71, 72 of the unfused portion. This heat sealing fuses and joins the outer surface of the mounting portion 21 to the packaging materials 71 and 72, and as shown in Figure 2, the mounting portion 21 is fixed to the peripheral seal portion 80 in a manner such that it is sandwiched between the packaging materials 71 and 72.

[0040] The adhesive member 60 is configured to be bonded to both the valve structure 10 and the housing 70 by heat sealing. When the valve structure 10 is attached to the housing 70, the adhesive strength between the adhesive member 60 and the housing 70 is such that the adhesion between the adhesive member 60 and the housing 70 is not broken even when the pressure in the internal space S1 of the housing 70 reaches the pressure at which the check valve 40 opens. Various known adhesive films can be used as the adhesive member 60. For example, the adhesive member 60 may be a single-layer film of maleic anhydride-modified polypropylene (PPa), or a multi-layer laminate film of PPa, polyethylene naphthalate (PEN), and PPa. It may also be a multi-layer laminate film of PPa, polypropylene (PP), and PPa. Instead of the PPa resin, resins capable of bonding to metals, such as ionomer resin, modified polyethylene, and EVA, can also be used. In this embodiment, the adhesive member 60 is a three-layer laminate film containing a core material, consisting of PPa / polyester fiber / PPa. The core material may be any of various known materials other than the polyester fiber described above. For example, the core material may be a polyester film such as PEN, a polyamide fiber, or a carbon fiber.

[0041] The connecting portion 22 is a portion that connects the mounting portion 21 and the tubular portion 23. The connecting portion 22 is arranged outside the peripheral seal portion 80. In this embodiment, the connecting portion 22 is formed integrally with the mounting portion 21. The connecting portion 22 may be configured as a separate body from the mounting portion 21. The connecting portion 22 is connected to the tubular portion 23 by being inserted inside the tubular portion 23. The connecting portion 22 may be joined to the tubular portion 23 by welding or crimping.

[0042] The mounting portion 21 and the connecting portion 22 have a common central axis C1 (see FIG. 4). In other words, the mounting portion 21 and the connecting portion 22 extend coaxially about the central axis C1. The mounting portion 21 has a first passage 20A1. The connecting portion 22 has a second passage 20A2. The first passage 20A1 and the second passage 20A2 extend coaxially about the central axis C1. In this embodiment, the cross sections of the first passage 20A1 and the second passage 20A2 perpendicular to the central axis C1 are circular. The first passage 20A1 and the second passage 20A2 are in communication with each other and constitute a part of the passage 20A. The second passage 20A2 is disposed closer to the exterior of the container 70A than the first passage 20A1.

[0043] 4 is a bottom view of the valve outer body 20. The mounting portion 21 has a non-circular outer shape when viewed along the direction in which the central axis C1 extends. More specifically, when viewed along the direction in which the central axis C1 extends, the mounting portion 21 has a first wing-shaped portion 21A that is formed to become thinner from the center in the left-right direction toward the left, and a second wing-shaped portion 21B that is formed to become thinner toward the right, when viewed along the direction in which the central axis C1 extends. Therefore, in this embodiment, the mounting portion 21 becomes thicker as it approaches the center in the width direction (left-right direction) of the electricity storage device 1, and becomes thinner as it approaches the ends in the width direction (left-right direction) of the electricity storage device 1.

[0044] In this embodiment, because the first wing-shaped portion 21A and the second wing-shaped portion 21B are formed, the outer peripheral surface of the mounting portion 21 forms a smoothly curved surface in both the lower half covered by the packaging material 71 and the upper half covered by the packaging material 72. Furthermore, compared to a case where the mounting portion 21 is formed cylindrically, the first wing-shaped portion 21A and the second wing-shaped portion 21B smooth the change in thickness of the power storage device 1 in the vertical direction at the transition position from the portion of the peripheral seal portion 80 where the mounting portion 21 is not sandwiched to the portion of the peripheral seal portion 80 where the mounting portion 21 is sandwiched. As a result, excessive force is not applied to the packaging materials 71 and 72 in the peripheral seal portion 80 around the position where the mounting portion 21 is attached. Therefore, the mounting portion 21 can be firmly fixed to the peripheral seal portion 80 via the adhesive member 60.

[0045] The outer shape of the connecting portion 22 is generally similar to a cylinder with a central axis C1 as its central axis, with a portion cut out. More specifically, the outer shape of the connecting portion 22 is generally similar to a cylinder with a central axis C1 as its central axis, with a plane cut out at a certain distance from the central axis C1 and a further plane cut out symmetrically to the plane with respect to the central axis C1. Thus, the connecting portion 22 has a pair of planes, a first plane 23XA and a second plane 23XB. The first plane 23XA and the second plane 23XB are parallel to each other (including when they are approximately parallel; the same applies below). The first plane 23XA and the second plane 23XB are parallel to the direction in which the central axis C1 extends (including when they are approximately parallel; the same applies below). In this embodiment, the first plane 23XA and the second plane 23XB are parallel to the direction in which the peripheral seal portion 80 extends (including when they are approximately parallel; the same applies below). The outer circumferential surface of the connecting portion 22 is composed of a first flat surface 23XA, a second flat surface 23XB, and curved surfaces 23C and 23D connecting the first flat surface 23XA and the second flat surface 23XB. When viewed along the direction of extension of the central axis C1, the curved surfaces 23C and 23D each have an arc shape centered on the central axis C1 and overlap the outer shape of the tubular portion 23. The connecting portion 22 described above can be formed by cutting the outer circumferential surface of a cylindrical member so as to form the first flat surface 23XA and the second flat surface 23XB. This configuration of the outer shape of the connecting portion 22 makes it easy to grip the valve structure 10. This facilitates, for example, transporting the valve structure 10 to a processing position and fixing the valve structure 10 at the processing position. This facilitates attachment of the valve structure 10 to the container 70A.

[0046] The tubular portion 23 shown in FIG. 3 has, for example, a cylindrical shape and a third passage 20A3 formed therein. The third passage 20A3 is in communication with the first passage 20A1 and the second passage 20A2. The first passage 20A1, the second passage 20A2, and the third passage 20A3 form a passage 20A. The tubular portion 23 has a first straight portion 23X, a first curved portion 23A, a second straight portion 23Y, a second curved portion 23B, and a third straight portion 23Z. The first straight portion 23X extends coaxially with the mounting portion 21 and the connecting portion 22, with the central axis C1 as its central axis. The first curved portion 23A is continuous with the first straight portion 23X and has an upwardly convex shape. The second straight portion 23Y is continuous with the first curved portion 23A. The second curved portion 23B is continuous with the second straight portion 23Y and has a downwardly convex shape. The third straight portion 23Z is continuous with the second curved portion 23B. As a result, the tubular portion 23 extends while being curved in an S-shape as a whole.

[0047] The liquid reservoir section 30 prevents moisture from entering the internal space S1. The liquid reservoir section 30 is located within the passage 20A and stores the liquid 200, through which the gas generated from the electricity storage device element 100 can pass. In this embodiment, the liquid reservoir section 30 is disposed in the second curved section 23B, and its function is realized by the curved shape of the second curved section 23B. That is, when the electricity storage device 1 is used with the upper side of FIG. 1 facing upward, the liquid 200 can be stored in the liquid reservoir section 30. On the other hand, even when the electricity storage device 1 is used with the direction perpendicular to the plane of FIG. 1 as the up-down direction, the liquid 200 can be stored in the liquid reservoir section 30 by, for example, attaching a partition member 380 (see FIGS. 6 and 7), which will be described later. However, the position of the liquid reservoir section 30 within the tubular section 23 is not limited to this and can be selected arbitrarily. In a preferred example, as shown in FIG. 1, the liquid reservoir 30 is located at a distance inside the container 70A from the opening 20AY so that the liquid 200 stored in the liquid reservoir 30 is less likely to flow out of the valve outer body 20 through the opening 20AY.

[0048] The liquid 200 stored in the liquid reservoir 30 can be any material that allows at least a portion of the gas generated from the electricity storage device element 100 to pass through but does not allow liquid to pass through. In this embodiment, the liquid 200 is liquid paraffin. Liquid oil such as silicone oil, or an ionic liquid, can also be used as the liquid 200. In a preferred example, the liquid 200 preferably has the property of remaining in liquid form under the normal usage environment of the electricity storage device 1. From this perspective, the melting point of the liquid 200 is preferably 10°C or lower, more preferably 0°C or lower. Similarly, the boiling point of the liquid 200 is preferably 150°C or higher. In this embodiment, the temperatures exemplified as the melting point and boiling point of the liquid 200 are temperatures under the normal usage environment of the electricity storage device 1. The electricity storage device 1 of this embodiment is used, for example, under atmospheric pressure or in a vacuum. The electricity storage device 1 may also be used in environments other than atmospheric pressure or in a vacuum.

[0049] The discharge portion 24 is continuous with the third linear portion 23Z of the cylindrical portion 23. In this embodiment, the discharge portion 24 is formed integrally with the cylindrical portion 23. The discharge portion 24 may be formed separately from the cylindrical portion 23. The discharge portion 24 has an opening 24AY. The discharge portion 24 is shaped so that the opening area of ​​the opening 24AY increases from the inside to the outside of the container 70A. Gas that is generated from the electricity storage device element 100 and passes through the liquid 200 stored in the liquid reservoir portion 30 is discharged to the outside through the opening 24AY.

[0050] The check valve 40 opens when the internal pressure of the container 70A increases due to gas generated from the power storage device element 100 inside the container 70A, allowing the gas to pass from the inside to the outside of the container 70A. When the internal pressure of the container 70A decreases, the check valve 40 closes to prevent the gas from passing from the inside to the outside of the container 70A. In other words, the check valve 40 is a gas vent valve. The valve structure 10 includes the check valve 40, which can prevent, for example, gas generated from the power storage device element 100 from flowing back from the outside to the inside of the container 70A. Furthermore, the internal pressure of the internal space S1 can be easily controlled. The position at which the check valve 40 is disposed in the valve outer body 20 can be arbitrarily selected. In this embodiment, the check valve 40 is disposed closer to the interior of the container 70A than the liquid reservoir portion 30. More specifically, the check valve 40 is disposed within the first straight portion 23X of the tubular portion 23. The structure of the check valve 40 is not particularly limited, but it can be a spring-type valve. A spring-type valve has a valve seat, a valve element, and a spring. When the internal pressure of the container 70A increases, the valve element moves away from the valve seat to open the spring-type valve, and when the internal pressure of the container 70A decreases, the spring presses the valve element against the valve seat to make a tight seal, closing the valve. Alternatively, the check valve 40 can be a poppet-type, duckbill-type, umbrella-type, diaphragm-type, or the like.

[0051] When gas is generated in the internal space S1 of the container 70A in accordance with the operation of the electricity storage device 1, the pressure in the internal space S1 gradually increases. When the pressure in the internal space S1 increases to a predetermined pressure, the check valve 40 opens, and the gas passes through the opening 20AX, the first passage 20A1, the second passage 20A2, the third passage 20A3, and the check valve 40. At least a portion of the gas that passes through the check valve 40 passes through the liquid 200 stored in the liquid reservoir 30 and is discharged to the outside through the opening 20AY. This makes it less likely that the internal pressure in the internal space S1 will increase excessively, causing the container 70A to burst.

[0052] The membrane filter 50 prevents the organic solvent contained in the electricity storage device element 100 from passing through the passage 20A and flowing out of the valve exterior body 20. In the valve exterior body 20, the position at which the membrane filter 50 is disposed can be selected arbitrarily as long as it is closer to the interior of the container 70A than the liquid reservoir section 30. In this embodiment, the membrane filter 50 is disposed in the first straight section 23X of the tubular section 23, closer to the interior of the container 70A than the check valve 40. In this embodiment, a lid material is preferably disposed near the opening 20AY to prevent the liquid 200 from leaking out from the opening 20AY. The lid material may be, for example, a metal mesh, a synthetic resin mesh, or a nonwoven fabric.

[0053] <1-3. Function and effect of the valve structure> If moisture enters the valve outer body 20 through the opening 20AY, the moisture is prevented from entering further into the container 70A than the liquid reservoir 30 by the liquid 200 stored in the liquid reservoir 30. This prevents moisture from entering the container 70A.

[0054] <1-4. Effects of the First Embodiment> The valve structure 10 configured as above can further provide the following effects.

[0055] <1-4-1> Liquid reservoir 30 is located at a position away from opening 20AY on the interior side of container 70A, so that liquid 200 stored in liquid reservoir 30 is less likely to flow out from opening 20AY to the outside.

[0056] <1-4-2> The function of the liquid reservoir 30 is realized by the curved shape of the second curved portion 23B, which allows the configuration of the liquid reservoir 30 to be simplified.

[0057] <1-5. Test> The inventors of the present application manufactured electricity storage devices of Examples and Reference Examples and conducted tests to confirm the extent to which moisture penetrated into the container. Note that, for the sake of convenience of explanation, the following description will be given by assigning the same reference numerals as in the first embodiment to the elements constituting the electricity storage devices of Examples and Reference Examples that are the same as in the first embodiment.

[0058] The electricity storage device 1 of the example has substantially the same configuration as the electricity storage device 1 of the first embodiment. The electricity storage device 1 of the example does not include the tab 90A and the tab film 90B, and includes only an electrolyte as the electricity storage device element 100. The mass of the electrolyte is 3 g. Liquid paraffin is stored as the liquid 200 in the liquid reservoir 30 of the electricity storage device 1 of the example. The volume of the liquid 200 stored in the liquid reservoir 30 is 1 ml.

[0059] The electricity storage device 1 of the reference example has the same configuration as the electricity storage device 1 of the example, except that the liquid 200 is not stored in the liquid reservoir 30 and the opening 20AY of the discharge section 24 is closed.

[0060] In this test, the electricity storage devices 1 of the examples and reference examples were stored for one week under conditions of a temperature of 60°C and a humidity of 90%. After that, the container 70A was opened, and the amount of water contained in the electrolyte was measured using a Karl Fischer water content meter.

[0061] The amount of moisture contained in the electrolyte of the electricity storage device 1 of the reference example was 200 ppm. The amount of moisture contained in the electrolyte of the electricity storage device 1 of the example was also 200 ppm. From these results, it was confirmed that the electricity storage device 1 of the example is less susceptible to moisture penetration from the outside, similar to when the opening 20AY is closed.

[0062] [2. Second Embodiment] The second embodiment differs from the first embodiment in the configuration of the valve structure 10. Other configurations are basically the same as those of the first embodiment. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and their description will be omitted, with the focus being on the differences from the first embodiment.

[0063] <2-1. Valve structure configuration> 5 is a cross-sectional view of a valve structure 210 included in an electricity storage device 1 of the second embodiment. The valve structure 210 includes a valve outer body 220 having a passage 220A formed therein, and a liquid reservoir 270 located within the passage 220A. In this embodiment, as in the first embodiment, at least one of the check valve 40 and the membrane filter 50 can also be disposed in the passage 220A closer to the interior of the container 70A than the liquid reservoir 270.

[0064] A passage 220A formed inside the valve outer body 220 is a passage that connects the inside and outside of the container 70A (see FIG. 1). The passage 220A has an opening 220AX that faces the internal space S1 of the container 70A and an opening 220AY that faces the external space. The valve outer body 220 has an attachment portion 230, a cylindrical portion 240, a housing 250, and a guide wall 260.

[0065] The attachment portion 230 is a portion for attaching the valve structure 210 to the container 70A, and has substantially the same configuration and function as the attachment portion 21 of the first embodiment. A first passage 220A1 is formed inside the attachment portion 230.

[0066] The tubular portion 240 has a generally cylindrical shape, and a second passage 220A2 is formed therein. The tubular portion 240 may be formed integrally with the attachment portion 230, or may be formed separately. The second passage 220A2 communicates with the first passage 220A1. The maximum diameter of the second passage 220A2 is larger than the maximum diameter of the first passage 220A1. An opening 240X that faces the internal space 250A of the housing 250 is formed at the end of the tubular portion 240 opposite the attachment portion 230.

[0067] The housing 250 has a front wall (not shown), a rear wall 251, a pair of side walls 252, an upper wall 253, and a bottom wall 254. The front wall, rear wall 251, the pair of side walls 252, the upper wall 253, and the bottom wall 254 of the housing 250 are joined together to form an internal space 250A. The first passage 220A1, the second passage 220A2, and the internal space 250A form the passage 220A. The front wall and the rear wall 251 face each other across the internal space 250A and the guide wall 260. The pair of side walls 252 face each other across the internal space 250A and the guide wall 260. The upper wall 253 and the bottom wall 254 face each other across the internal space 250A and the guide wall 260.

[0068] An opening 220AY is formed in the upper wall 253, which discharges gas that has passed through the liquid reservoir portion 270 to the outside space. The opening 220AY is formed in approximately the center in the left-right direction. An opening 254A is formed in the bottom wall 254, into which the cylindrical portion 240 is inserted. The maximum diameter of the opening 254A is substantially equal to or slightly larger than the maximum diameter of the cylindrical portion 240. The opening 254A is formed in approximately the center in the left-right direction.

[0069] The guide wall 260 guides the gas that has passed through the opening 240X of the cylindrical portion 240 to the liquid reservoir portion 270. The guide wall 260 is supported by at least one of the front wall and the rear wall 251. The guide wall 260 has a first wall 261 and a pair of second walls 262. The first wall 261 is disposed to face the opening 240X of the cylindrical portion 240. The length XA of the first wall 261 in the left-right direction is longer than the maximum diameter XB of the cylindrical portion 240. Therefore, the first wall 261 comes into contact with a large amount of gas that has passed through the opening 240X, and can guide the gas to the liquid reservoir portion 270. The second wall 262 extends from an end of the first wall 261 in the left-right direction toward the bottom wall 254. The gas that has passed through the opening 240X of the cylindrical portion 240 comes into contact with the first wall 261, disperses in the left-right direction, and is guided along the second wall 262 to the liquid reservoir portion 270.

[0070] The liquid reservoir 270 is located in a portion defined by the pair of side walls 252, the cylindrical portion 240, and the bottom wall 254. The liquid level of the liquid 200 stored in the liquid reservoir 270 is located closer to the bottom wall 254 than the opening 240X of the cylindrical portion 240.

[0071] <2-2. Function and effect of the valve structure> The electricity storage device 1 is used with the valve structure 210 positioned above the housing 70. When the pressure in the internal space S1 increases to a predetermined pressure due to gas generated from the electricity storage device element 100, the gas passes through the first passage 220A1, the second passage 220A2, and the opening 240X and flows into the internal space 250A. The gas that flows into the internal space 250A comes into contact with the first wall 261 of the guide wall 260 and disperses in the left-right direction. At least a portion of the gas dispersed in the left-right direction flows along the second wall 262 and passes through the liquid 200 stored in the liquid reservoir 270. The gas that has passed through the liquid 200 rises in the internal space 250A and is discharged from the opening 220AY to the external space. This makes it less likely that the internal pressure in the internal space S1 will increase excessively, causing the container 70A to burst. On the other hand, if moisture enters the valve outer body 220 through the opening 220AY, the moisture is prevented from entering further into the container 70A than the liquid reservoir 270 by the liquid 200 stored in the liquid reservoir 270. This prevents moisture from entering the container 70A.

[0072] <2-3. Effects of the Second Embodiment> The valve structure 210 configured as above can further provide the following effects.

[0073] <2-3-1> Liquid reservoir 270 is located at a position away from opening 220AY on the interior side of container 70A, so that liquid 200 stored in liquid reservoir 270 is less likely to flow out from opening 220AY to the outside.

[0074] <2-3-2> The liquid reservoir 270 is located in a section defined by the pair of side walls 252, the cylindrical portion 240, and the bottom wall 254. This allows the configuration of the liquid reservoir 270 to be simplified.

[0075] 3. Third Embodiment The third embodiment differs from the first embodiment in the configuration of the valve structure 10. The other configurations are basically the same as those of the first embodiment. In the following, the same components as those of the first embodiment are given the same reference numerals, and their description will be omitted, and the description will focus on the parts that are different from the first embodiment.

[0076] <3-1. Valve structure configuration> 6 is a cross-sectional view of a valve structure 310 included in an electricity storage device 1 of the third embodiment. The valve structure 310 includes a valve outer body 320 having a passage 320A formed therein, and a liquid reservoir 370 located within the passage 320A. In this embodiment, as in the first embodiment, at least one of the check valve 40 and the membrane filter 50 can also be disposed within the passage 320A closer to the interior of the container 70A than the liquid reservoir 370.

[0077] A passage 320A formed inside the valve outer body 320 is a passage that connects the inside and outside of the container 70A (see FIG. 1). The passage 320A has an opening 320AX that faces the internal space S1 of the container 70A and an opening 320AY that faces the external space. The valve outer body 320 has an attachment portion 330, a cylindrical portion 340, and a discharge portion 350.

[0078] The attachment portion 330 is a portion for attaching the valve structure 310 to the container 70A, and has substantially the same configuration and function as the attachment portion 21 of the first embodiment. A first passage 320A1 is formed inside the attachment portion 330.

[0079] The cylindrical portion 340 has a generally cylindrical shape, and a second passage 320A2 is formed therein. The first passage 320A1 and the second passage 320A2 form a passage 320A. The diameter of the cylindrical portion 340 decreases slightly from the opening 320AY toward the opening 320AX. The cylindrical portion 340 may be formed integrally with the mounting portion 330 or may be formed separately. The second passage 320A2 is in communication with the first passage 320A1. The maximum diameter of the second passage 320A2 is larger than the maximum diameter of the first passage 320A1.

[0080] The discharge portion 350 is continuous with the cylindrical portion 340. In this embodiment, the discharge portion 350 is formed integrally with the cylindrical portion 340. The discharge portion 350 may be formed separately from the cylindrical portion 340. An opening 320AY is formed in the discharge portion 350. The discharge portion 350 is shaped so that the opening area of ​​the opening 320AY increases from the inside to the outside of the container 70A. Gas generated from the electricity storage device element 100 and passing through the liquid 200 stored in the liquid reservoir portion 370 is discharged to the outside through the opening 320AY.

[0081] The liquid reservoir 370 is supported by the valve outer body 320 and includes a partition member 380 that partitions a storage space S2 in the passage 320A for storing the liquid 200. The position of the liquid reservoir 370 within the tubular portion 340 can be selected as desired. In a preferred example, the liquid reservoir 370 is positioned at a distance toward the interior of the container 70A from the opening 320AY so that the liquid 200 stored in the liquid reservoir 370 is less likely to flow out of the valve outer body 320 through the opening 320AY. The material constituting the partition member 380 can be selected as desired, as long as it is a material that can store the liquid 200 stored in the storage space S2. The material constituting the partition member 380 is, for example, a metal mesh, a synthetic resin mesh, or a nonwoven fabric.

[0082] The partitioning member 380 has, for example, a circular shape in a plan view. The partitioning member 380 includes a first partitioning member 381 and a second partitioning member 382 that is positioned closer to the opening 320AY than the first partitioning member 381. As described above, the diameter of the tubular portion 340 decreases slightly from the opening 320AY toward the opening 320AX. The maximum outer diameters of the first partitioning member 381 and the second partitioning member 382 are equal to or smaller than the maximum inner diameter of the tubular portion 340. Therefore, when the first partitioning member 381 and the second partitioning member 382 are inserted into the tubular portion 340 through the opening 320AY, they are supported by the tubular portion 340 at any position within the tubular portion 340. The maximum outer diameter of the first partitioning member 381 is smaller than the maximum outer diameter of the second partitioning member 382. Note that when the inner diameter of the tubular portion 340 is constant, a step protruding from the inner surface of the tubular portion 340 is formed in the tubular portion 340 to support the partitioning member 380. The partition member 380 has a plurality of minute holes 380A. The size of the holes 380A is such that the liquid 200 contained in the containing space S2 can be held therein by surface tension.

[0083] <3-2. Function and effect of valve structure> The electricity storage device 1 is used with the valve structure 310 positioned above the housing 70. When the pressure in the internal space S1 rises to a predetermined pressure due to gas generated from the electricity storage device element 100, the gas passes through the opening 320AX and the first passage 320A1 and flows into the second passage 320A2. At least a portion of the gas that flows into the second passage 320A2 passes through the hole 380A of the first partitioning member 381 and passes through the liquid 200 stored in the liquid reservoir 370. The gas that has passed through the liquid 200 passes through the hole 380A of the second partitioning member 382, ​​rises through the second passage 320A2, and is discharged to the external space through the opening 320AY. This makes it less likely that the internal pressure in the internal space S1 will rise excessively, causing the container 70A to burst. On the other hand, if moisture enters the valve outer body 320 through the opening 320AY, the moisture is prevented from entering further into the container 70A than the liquid reservoir 370 by the liquid 200 stored in the liquid reservoir 370. This prevents moisture from entering the container 70A.

[0084] <3-3. Effects of the Third Embodiment> The valve structure 310 configured as above can further provide the following effects.

[0085] Liquid reservoir 370 is located at a position away from opening 320AY on the interior side of container 70A, so that liquid 200 stored in liquid reservoir 370 is less likely to flow out through opening 320AY to the outside.

[0086] [4. Fourth Embodiment] The fourth embodiment differs from the third embodiment in the configuration of the valve structure 10. The other configurations are basically the same as those of the third embodiment. In the following, the same components as those of the third embodiment are denoted by the same reference numerals, and their description will be omitted, with the focus being on the differences from the third embodiment.

[0087] <4-1. Valve structure configuration> 7 is a cross-sectional view of a valve structure 410 included in an electricity storage device 1 of the third embodiment. The valve structure 410 has a liquid reservoir section 470. The liquid reservoir section 470 has a partition member 380 similar to that of the third embodiment, and a holding member 383 capable of holding liquid 200. The holding member 383 is supported by at least one of the valve outer body 320 and the partition member 380. In this embodiment, the holding member 383 is supported by a first partition member 381.

[0088] The holding member 383 has a shape that seals the storage space S2. In this embodiment, the holding member 383 has a cylindrical shape. Any material can be selected from the holding member 383 as long as it is a material that can hold the liquid 200. The material from which the holding member 383 is made is, for example, a porous material. The porous material is, for example, paper, cloth, nonwoven fabric, sponge, or the like.

[0089] <4-2. Function and effect of valve structure> According to the valve structure 410 of the fourth embodiment, in addition to the same actions and effects as those obtained by the valve structure 310 of the third embodiment, the following effect can be obtained.

[0090] Since the holding member 383 is disposed in the accommodation space S2, the liquid 200 can be easily stored in the liquid reservoir section 370.

[0091] [5. Fifth Embodiment] The fifth embodiment differs from the first embodiment in the configuration of the valve structure 10. The other configurations are basically the same as those of the first embodiment. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and their description will be omitted, with the focus being on the differences from the first embodiment.

[0092] <5-1. Valve structure configuration> 8 is a cross-sectional view of a valve structure 510 included in an electricity storage device 1 of the fifth embodiment. The valve structure 510 includes a valve outer body 520 having a passage 520A formed therein, and a liquid reservoir 570 located within the passage 520A. In this embodiment, as in the first embodiment, at least one of the check valve 40 and the membrane filter 50 can also be disposed in the passage 520A closer to the interior of the container 70A than the liquid reservoir 570.

[0093] A passage 520A formed inside the valve outer body 520 is a passage that connects the inside and outside of the container 70A (see FIG. 1). The passage 520A has an opening 520AX that faces the internal space S1 of the container 70A and an opening 520AY that faces the external space. The valve outer body 520 has an attachment portion 530, a nozzle 540, and a housing 550.

[0094] The mounting portion 530 is a portion for mounting the valve structure 510 to the container 70A, and has substantially the same configuration and function as the mounting portion 51 of the first embodiment. Inside the mounting portion 530, a first passage 520A1 is formed.

[0095] A second passage 520A2 is formed inside the nozzle 540. The nozzle 540 is connected to the mounting portion 530 and has a tapered shape as it approaches the liquid reservoir portion 570, in other words, as it approaches the opening 520AY. Therefore, the diameter of the second passage 520A2 decreases as it approaches the opening 520AY. An opening 540X facing the internal space 550A of the housing 550 is formed at the end of the nozzle 540 opposite the mounting portion 530. The nozzle 540 may be formed integrally with the mounting portion 530 or may be formed separately. At least a portion of the nozzle 540 is located in the internal space 550A of the housing 550. In this embodiment, the entire nozzle 540 is located in the internal space 550A.

[0096] The housing 550 has a front wall (not shown), a rear wall 551, a pair of side walls 552, an upper wall 553, and a bottom wall 554. The front wall, rear wall 551, the pair of side walls 552, the upper wall 553, and the bottom wall 554 are joined together to form an internal space 550A. The first passage 520A1, the second passage 520A2, and the internal space 550A form the passage 520A. The front wall and the rear wall 551 face each other across the internal space 550A. The pair of side walls 552 face each other across the internal space 550A. The upper wall 553 and the bottom wall 554 face each other across the internal space 550A.

[0097] An opening 520AY is formed in the upper wall 553, through which gas that has passed through the liquid reservoir 570 is discharged to the outside space. The opening 520AY is formed in approximately the center in the left-right direction. An opening 554A is formed in the bottom wall 554, into which the mounting portion 530 and the nozzle 540 are inserted. The maximum diameter of the opening 554A is substantially equal to or slightly larger than the maximum diameter of the mounting portion 530. The opening 554A is formed in approximately the center in the left-right direction.

[0098] Liquid reservoir 570 is located in a portion defined by a pair of side walls 552, nozzle 540, and bottom wall 554. The liquid level of liquid 200 stored in liquid reservoir 570 is located closer to upper wall 553 than opening 540X of nozzle 540.

[0099] <5-2. Function and effect of valve structure> The electricity storage device 1 is used with the valve structure 510 positioned above the container 70. When the pressure in the internal space S1 rises to a predetermined pressure due to gas generated from the electricity storage device element 100, the gas flows through the first passage 520A1, the second passage 520A2, and the opening 540X into the internal space 550A. The gas that flows into the internal space 550A passes through the liquid 200 stored in the liquid reservoir 570. The gas that has passed through the liquid 200 rises in the internal space 550A and is discharged to the external space through the opening 520AY. This makes it less likely that the internal pressure of the internal space S1 will rise excessively, causing the container 70A to burst. On the other hand, if moisture enters the valve exterior body 520 through the opening 520AY, the liquid 200 stored in the liquid reservoir 570 will prevent the moisture from penetrating further into the container 70A than the liquid reservoir 570. This prevents moisture from entering the container 70A.

[0100] <5-3. Effects of the Fifth Embodiment> The valve structure 510 configured as above can further provide the following effects.

[0101] <5-3-1> Liquid reservoir 570 is located at a position away from opening 520AY on the interior side of container 70A, so that liquid 200 stored in liquid reservoir 570 is less likely to flow out from opening 520AY to the outside.

[0102] <5-3-2> The liquid reservoir 570 is located in a portion defined by the pair of side walls 552, the nozzle 540, and the bottom wall 554. This allows the configuration of the liquid reservoir 270 to be simplified.

[0103] <5-3-3> Nozzle 540 has a tapered shape toward liquid reservoir 570, in other words, toward opening 520AY, and therefore second passage 520A2 also has a reduced diameter toward opening 520AY. Therefore, gas that has passed through second passage 520A2 tends to turn into bubbles when passing through opening 540X and flow into liquid 200. Therefore, gas tends to pass through liquid 200 more quickly.

[0104] [6. Sixth Embodiment] The sixth embodiment differs from the first embodiment in the configuration of the valve structure 10. The other configurations are basically the same as those of the first embodiment. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and their description will be omitted, with the focus being on the differences from the first embodiment.

[0105] <6-1. Valve structure configuration> FIG. 9 is a plan view of an electricity storage device 1 according to a sixth embodiment. However, in FIG. 9, portions that are not normally visible from the outside are partially shown by dashed lines for reference. The valve structure 610 included in the electricity storage device 1 has a pattern seal portion 620 and a liquid reservoir portion 630. The pattern seal portion 620 is a portion of the peripheral seal portion 80 where the packaging materials 71 and 72 are not partially fused together. The pattern seal portion 620 can be formed at any position in the peripheral seal portion 80. In this embodiment, the pattern seal portion 620 is formed on one of a pair of long sides of the peripheral seal portion 80.

[0106] In the pattern sealed portion 620, a passage 620A that connects the inside and outside of the container 70A is formed in a portion where the packaging material 71 and the packaging material 72 are not partially heat-sealed. The number of passages 620A formed in the pattern sealed portion 620 can be selected arbitrarily. In this embodiment, four passages 620A are formed in the pattern sealed portion 620. The number of passages 620A formed in the pattern sealed portion 620 may be one to three, or four or more. The passage 620A has an opening 620AX that faces the internal space S1 of the container 70A and an opening 620AY that faces the external space.

[0107] The liquid reservoir 630 includes a holding member 631 arranged to cross the multiple passages 620A in the left-right direction. The holding member 631 has a function similar to that of the holding member 383 described in the fourth embodiment, for example. The holding member 631 is sandwiched between the packaging materials 71 and 72 and fused to the packaging materials 71 and 72 by a seal bar that performs pattern sealing. Therefore, only the portion of the holding member 631 located in the passages 620A has the function of holding the liquid 200.

[0108] <6-2. Function and effect of valve structure> When the pressure in the internal space S1 rises to a predetermined pressure due to gas generated from the electricity storage device element 100, the gas flows from the opening 620AX into the passage 620A. The gas that flows into the passage 620A passes through the liquid 200 held in the holding member 631 and is discharged to the external space through the opening 620AY. This makes it less likely that the internal pressure in the internal space S1 will rise excessively, causing the container 70A to burst. On the other hand, when moisture enters the passage 620A from the opening 620AY, the liquid 200 held in the liquid reservoir 630 will prevent the moisture from penetrating further into the container 70A than the liquid reservoir 630. This prevents moisture from penetrating into the container 70A.

[0109] 6-3. Effects of the Sixth Embodiment The valve structure 610 configured as above can further provide the following effects.

[0110] <6-3-1> Since the valve structure 610 is located inside the outer periphery of the container 70A, the size of the electricity accumulation device 1 can be reduced.

[0111] [7. Seventh Embodiment] The seventh embodiment differs from the first embodiment in the configuration of the valve structure 10. Other configurations are basically the same as those of the first embodiment. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and their description will be omitted, with the focus being on the differences from the first embodiment.

[0112] <7-1. Valve structure configuration> FIG. 10 is a front view of a valve structure 710 of the seventh embodiment. However, in FIG. 10, parts that are not normally visible from the outside are partially shown with dashed lines for reference. The valve structure 710 is configured so that it can be attached to multiple containers 70A. The valve structure 710 includes a valve outer body 720 having a passage 720A formed therein, and a liquid reservoir 770 located within the passage 720A. Note that in this embodiment, as in the first embodiment, at least one of the check valve 40 and the membrane filter 50 can also be disposed in the passage 720A closer to the interior of the container 70A than the liquid reservoir 770.

[0113] The material constituting the valve outer body 720 can be selected arbitrarily. The material constituting the valve outer body 720 is preferably a highly flexible material so that it can deform according to the arrangement of the multiple containers 70A. One example of a highly flexible material is a flexible synthetic resin. Examples of flexible synthetic resins include olefin resin, polyester resin, acrylic resin, urethane resin, fluororesin, and synthetic rubber. The material constituting the valve outer body 720 may be a synthetic resin alone, or a composite material with metal to provide barrier properties. For example, aluminum foil may be laminated onto the synthetic resin, or a thin film of aluminum oxide or other oxide may be laminated onto the synthetic resin. Furthermore, since bendable portions of the valve outer body 720 require flexibility during use, they may be made of synthetic resin, while straight portions that cannot be bent during use may be made of highly rigid metal. In other words, the valve outer body 720 may be constructed by combining components made of synthetic resin and components made of metal.

[0114] A passage 720A formed inside the valve outer body 720 is a passage that connects the inside and outside of the container 70A (see FIG. 1). The passage 720A has an opening 720AX that faces the internal space S1 of the container 70A and an opening 720AY that faces the external space. The valve outer body 720 has an attachment portion 730, a plurality of branch portions 740, and a junction portion 750.

[0115] The mounting portion 730 is a portion for mounting the valve structure 710 to the container 70A, and has substantially the same configuration and function as the mounting portion 21 of the first embodiment. A first passage 720A1 is formed inside the mounting portion 730.

[0116] The multiple branch portions 740 are generally cylindrical, and have second passages 720A2 formed therein. The branch portions 740 may be formed integrally with the mounting portion 730 or may be formed separately. The number of branch portions 740 included in the valve structure 710 can be selected as desired, as long as it is two or more. In this embodiment, the valve structure 710 has three branch portions 740. The second passage 720A2 communicates with the first passage 720A1. The maximum diameter of the second passage 720A2 is larger than the maximum diameter of the first passage 720A1. The multiple branch portions 740 are attached to different containers 70A via the mounting portion 730.

[0117] The junction 750 has a generally cylindrical shape, and a third passage 720A3 is formed inside the junction 750. The third passage 720A3 communicates with the second passage 720A2, and is a passage where the second passages 720A2 formed in the multiple branching sections 740 join together.

[0118] Liquid reservoir 770 is located in at least one of third passage 720A3 and second passage 720A2. In this embodiment, liquid reservoir 770 is located in third passage 720A3. The specific configuration of liquid reservoir 770 can be, for example, the configurations exemplified in the first to fifth embodiments. As shown by the dashed dotted line in FIG. 10, when liquid reservoir 770 is located in second passage 720A2, the specific configuration can be, for example, the configuration exemplified in the third or fourth embodiment.

[0119] <7-2. Function and effect of valve structure> The electricity storage device 1 is used with the valve structure 710 positioned above the housing 70. When the pressure in the internal space S1 rises to a predetermined pressure due to gas generated from the electricity storage device element 100, the gas flows from the opening 720AX into the first passage 720A1. The gas that flows into the first passage 720A1 flows into the second passage 720A2 and joins together at the third passage 720A3. The gas that joins together at the third passage 720A3 passes through the liquid 200 stored in the liquid reservoir 770. The gas that has passed through the liquid 200 rises through the third passage 720A3 and is discharged to the external space through the opening 720AY. This makes it less likely that the internal pressure in the internal space S1 will rise excessively, causing the container 70A to burst. On the other hand, if moisture enters the valve exterior body 720 through the opening 720AY, the moisture is prevented from entering further into the container 70A than the liquid reservoir 770 by the liquid 200 stored in the liquid reservoir 770. This prevents moisture from entering the container 70A.

[0120] <7-3. Effects of the Seventh Embodiment> The valve structure 710 configured as above can further provide the following effects.

[0121] <7-3-1> The valve structure 710 has a plurality of branch portions 740, and therefore can discharge gas generated from the electricity storage device elements 100 housed in a plurality of containers 70A to the outside, thereby improving convenience.

[0122] <8. Variations> The above-described embodiments are examples of possible forms of the valve structure and electricity storage device according to the present invention, and are not intended to limit the forms. The valve structure and electricity storage device according to the present invention may take forms different from those exemplified in the embodiments. Examples of such forms include forms in which part of the configuration of each embodiment is replaced, modified, or omitted, or forms in which a new configuration is added to the embodiment. Below are some examples of modified versions of each embodiment.

[0123] <8-1> The configuration of the valve structure 10 is not limited to that shown in the first embodiment and can be modified as desired. For example, the liquid reservoir 30 of the valve structure 10 can be located inside the container 70A. In this case, for example, the liquid reservoir 30 is located in the first passage 20A1. Note that this modification can also be applied to the second to fifth embodiments and the seventh embodiment.

[0124] <8-2> In the first embodiment, the connecting portion 22 of the valve outer body 20 can be omitted. In this case, the attachment portion 21 is connected to the cylindrical portion 23, or the attachment portion 21 and the cylindrical portion 23 are integrally formed.

[0125] <8-3> In the first to fifth embodiments and the seventh embodiment, at least one of the check valve 40 and the membrane filter 50 may be omitted. In the first embodiment, the membrane filter 50 needs to be placed more inward than the liquid reservoir section 30 (closer to the electricity storage device element 100). When the check valve 40 is placed more inward than the liquid reservoir section 30, the membrane filter 50 is preferably placed even further inward than the check valve 40. The same applies to the second to fifth embodiments and the seventh embodiment.

[0126] <8-4> In the third and fourth embodiments, the second partition member 382 of the liquid reservoir 370 may be omitted.

[0127] <8-5> In the first to seventh embodiments, container 70A is formed by heat-sealing packaging material 71 and packaging material 72 together, but container 70A may also be formed by folding a single sheet of packaging material and heat-sealing the peripheral edges.

[0128] <8-6> In the first embodiment, the cross-sectional shape of the cylindrical portion 23 may be any cross-sectional shape such as a polygonal shape, an elliptical shape, etc. The same applies to the cylindrical portion 240 of the second embodiment, the cylindrical portion 340 of the third and fourth embodiments, the attachment portion 530 of the fifth embodiment, and the branch portion 740 and the junction portion 750 of the seventh embodiment. [Explanation of symbols]

[0129] 1...electricity storage device, 10...valve structure, 20...valve outer body, 20A...passage, 20AY...opening, 21...mounting portion, 23...cylindrical portion, 23B...second curved portion (curved portion), 30...liquid reservoir portion, 40...check valve, 70...accommodation body, 70A...container, 71...packaging material, 72...packaging material, 100...electricity storage device element, 200...liquid, 210...valve structure, 220...valve outer body, 220A...passage, 220AY...opening, 230...mounting portion, 240...cylindrical portion, 270...liquid reservoir portion, 310...valve structure, 320...valve outer body Body, 320A...passage, 320AY...opening, 330...mounting portion, 383...retaining member, 340...cylindrical portion, 370...liquid reservoir, 410...valve structure, 510...valve structure, 520...valve outer body, 520A...passage, 520AY...opening, 530...mounting portion, 570...liquid reservoir, 610...valve structure, 620...pattern seal portion, 620A...passage, 620AY...opening, 630...liquid reservoir, 710...valve structure, 720...valve outer body, 720A...passage, 720AY...opening, 730...mounting portion, 770...liquid reservoir.

Claims

1. a passageway that connects the inside and outside of a container that accommodates the electricity storage device element; a liquid reservoir portion located within the passage for storing a liquid through which gas generated from the electricity storage device element can pass, the passage includes an opening for discharging the gas to the outside of the container; the liquid reservoir is located at a position on the inner side of the container away from the opening, a valve outer body having the passage formed therein; The valve outer body is a mounting portion fixed to the container; a cylindrical portion connected to the mounting portion and disposed outside the container, the tubular portion includes a curved portion; The liquid reservoir is located in the curved portion. Valve structure.

2. A passage that connects the inside and outside of a container that houses an electricity storage device element; a liquid reservoir portion located within the passage for storing a liquid through which gas generated from the electricity storage device element can pass, a valve outer body having the passage formed therein; The valve outer body is a mounting portion fixed to the container; a cylindrical portion connected to the mounting portion; a housing into which the cylindrical portion is inserted, The liquid reservoir is located within the housing. Valve structure.

3. The liquid reservoir further includes a partition member that is supported by the valve outer body and that partitions a storage space that stores the liquid within the passage. The valve structure according to claim 1 or 2.

4. A passage that connects the inside and outside of a container that houses an electricity storage device element; a liquid reservoir portion located within the passage for storing a liquid through which gas generated from the electricity storage device element can pass, a valve outer body having the passage formed therein; the valve outer body includes a mounting portion fixed to the container, The liquid reservoir portion is a partition member supported by the valve outer body and defining a storage space in the passage for storing the liquid; a holding member supported by at least one of the valve outer body and the partition member and capable of holding the liquid, The material constituting the holding member includes a porous material. Valve structure.

5. A passage that connects the inside and outside of a container that houses an electricity storage device element; a liquid reservoir portion located within the passage for storing a liquid through which gas generated from the electricity storage device element can pass, a valve outer body having the passage formed therein; The valve outer body is a mounting portion fixed to the container; a nozzle connected to the mounting portion and tapering toward the liquid reservoir portion. Valve structure.

6. a check valve that is disposed on the inner side of the container relative to the liquid reservoir and that opens when the internal pressure of the container increases due to the gas generated inside the container, allowing the gas to pass from the inside to the outside of the container. The valve structure according to any one of claims 1 to 5.

7. The melting point of the liquid is 0°C or less The valve structure according to any one of claims 1 to 6.

8. The boiling point of the liquid is 150°C or higher. The valve structure according to any one of claims 1 to 7.

9. The valve structure according to any one of claims 1 to 8, an internal space defined by the container and accommodating the power storage device element; Energy storage device.

10. A passage that connects the inside and outside of a container that houses an electricity storage device element; a liquid reservoir portion located within the passage for storing a liquid through which gas generated from the electricity storage device element can pass, the container includes a packaging material and a pattern seal portion that is a portion where the packaging material is partially fused to form a storage space for storing the electricity storage device element; The passage is formed in a portion of the pattern seal portion where the packaging material is not fused. Energy storage device.

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