Valve structure for energy storage device, and energy storage device

Abstract

A valve structure for a power storage device, comprising: a passage that connects the interior and exterior of a container that houses a power storage device element; and a non-return valve disposed so as to block the passage, opening when the internal pressure of the container increases due to gas generated inside the container and causing the gas to pass from the inside of the container to the outside. The non-return valve includes a valve seat and a valve body and comprises a liquid arranged so as to be in contact with the valve seat and the valve body.

Description

Technical Field

[0001] The present invention relates to a valve structure for a power storage device and a power storage device including the same.

Background Art

[0002] Patent Document 1 discloses a battery in which battery elements are housed in a pouch. A valve structure having a check valve is attached to a heat seal portion formed along the periphery of the pouch. This check valve operates when the internal pressure of the pouch rises above a certain level and is configured to vent gas.

[0003] Patent Document 2 discloses a battery in which battery elements are housed in a box-shaped laminate container. This laminate container has a portion (hereinafter referred to as an easy peel portion) that is more easily peeled than other portions formed in a flange-shaped heat seal portion formed along the periphery thereof. The easy peel portion peels off when the internal pressure of the laminate container rises above a certain level and vents gas through a hole formed in the center of the easy peel portion. Unlike the check valve as in Patent Document 1, the easy peel portion is a rupture valve that does not return to its original state once peeled off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, a check valve is generally a one-way valve and is intended to prevent backflow. However, in a battery such as that in Patent Document 1, even a small amount in the pouch I feel even a small amount invasionIf air enters, it will cause battery degradation, so a higher level of precision is required to prevent backflow. For this reason, it is practically difficult for a check valve that vents gas from inside the pouch, such as the one in Patent Document 1, to completely prevent air from entering the pouch at the high level required for batteries. Therefore, in batteries like the one in Patent Document 1, large amounts of air enter the pouch. Invading This presents a problem: battery degradation occurs.

[0006] On the other hand, in a battery like the one in Patent Document 2, once the failure valve is destroyed, air enters the laminate container through the passage formed by the destruction. Therefore, even when a failure valve is used as in Patent Document 2, large amounts of air enter the laminate container. Invading This presents a problem: battery degradation occurs.

[0007] This invention relates to the container in which the energy storage device element is housed. atmosphere The objective is to provide a valve structure that can prevent intrusion, and an energy storage device equipped therewith. [Means for solving the problem]

[0008] A valve structure for an energy storage device according to a first aspect of the present invention comprises a passage that connects the inside and outside of a container housing an energy storage device element, and a check valve that is arranged to close the passage and opens when the internal pressure of the container rises due to gas generated inside the container, thereby allowing the gas to pass from the inside to the outside of the container, wherein the check valve includes a valve seat and a valve body, and comprises a liquid arranged in contact with the valve seat and the valve body.

[0009] A valve structure for an energy storage device according to a second aspect of the present invention is a valve structure for an energy storage device according to a first aspect, wherein the melting point of the liquid is 10°C or lower.

[0010] A valve structure for an energy storage device according to a third aspect of the present invention is a valve structure for an energy storage device according to a first or second aspect, wherein the boiling point of the liquid is 150°C or higher.

[0011] A valve structure for an energy storage device according to the fourth aspect of the present invention is a valve structure for an energy storage device according to any one of the first or third aspects, wherein the liquid includes liquid paraffin.

[0012] A valve structure for an energy storage device according to the fifth aspect of the present invention is a valve structure for an energy storage device according to any one of the first or fourth aspects, wherein the viscosity of the liquid is in the range of 0.1 mPa·s to 2000 mPa·s.

[0013] A valve structure for an energy storage device according to the sixth aspect of the present invention is a valve structure for an energy storage device according to any one of the first to fifth aspects, wherein the passage includes an outlet facing the external space and has a sealing member attached to close the outlet.

[0014] A valve structure for an energy storage device according to the seventh aspect of the present invention is a valve structure for an energy storage device according to any one of the first to sixth aspects, and comprises a cover material disposed on at least one of the primary and secondary sides of the check valve and configured to allow the gas to pass through.

[0015] An energy storage device according to the eighth aspect of the present invention comprises a valve structure for an energy storage device according to any one of the first to seventh aspects, and the container to which the valve structure for the energy storage device is attached. [Effects of the Invention]

[0016] According to the valve structure for an energy storage device and the energy storage device of the present invention, into the container in which the energy storage device elements are housed atmosphere This can prevent them from entering. [Brief explanation of the drawing]

[0017] [Figure 1] A plan view of an energy storage device comprising a valve structure for an energy storage device according to the first embodiment. [Figure 2] A cross-sectional view along the line D2-D2 in Figure 1. [Figure 3] Front view of the valve structure in Figure 1. [Figure 4] Bottom view of the valve structure of FIG. 3. [Figure 5] Plan view of the valve structure of FIG. 3. <l [Figure 6] Perspective view of the valve structure of FIG. 3 as viewed from the rear side. [Figure 7A] Cross-sectional view taken along line D7-D7 of FIG. 4. [Figure 7B] Cross-sectional view of the seal member of FIG. 7A. [Figure 8] Cross-sectional view taken along line D8-D8 of FIG. 3. [Figure 9] Front view of the valve structure for a power storage device according to the second embodiment. <000l [Figure 10] Cross-sectional view taken along line D10-D10 of FIG. 9. [Figure 11] Cross-sectional view of the valve structure of the modification. [Figure 12] Cross-sectional view of the valve structure of another modification. [Figure 13] Cross-sectional view of the valve structure of yet another modification. [Figure 14] Plan view of the power storage device of the modification. [Figure 15] Plan view of the power storage device of another modification. [Figure 16] Plan view of the power storage device of yet another modification. [Figure 17] Plan view of the power storage device of yet another modification [Embodiments for Carrying Out the Invention]

[0018] Hereinafter, a valve structure for a power storage device according to an embodiment of the present invention, a power storage device including the same, and a manufacturing method thereof will be described with reference to the drawings. <l

[0019] [1. First Embodiment] [1-1. Overall Configuration of Power Storage Device] Figure 1 shows a plan view of a power storage device 100 equipped with a valve structure 10 for a power storage device according to this embodiment. Figure 2 is a cross-sectional view taken along the line D2-D2 in Figure 1. In these figures, parts that are not normally visible from the outside are partially shown with dotted lines for reference. Hereafter, for the sake of explanation, unless otherwise specified, the vertical direction in Figure 1 will be referred to as "front and back," the horizontal direction as "left and right," and the vertical direction in Figure 2 as "up and down." However, the orientation of the power storage device 100 when in use is not limited to these.

[0020] The energy storage device 100 comprises a housing 110, an energy storage device element 120, a tab 130, and a tab film 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the tab 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion between the one end and the other end is fused to the peripheral seal portion 150 via the tab film 140.

[0021] The containment body 110 includes a container 110A. The container 110A is composed of packaging materials 111 and 112. In a plan view, the packaging materials 111 and 112 are heat-sealed and fused together on the outer periphery of the container 110A, thereby forming a peripheral seal portion 150. This peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat sealing method described here may include heating and fusion from a heat source, ultrasonic fusion, etc. In any case, the peripheral seal portion 150 refers to the part where the packaging materials 111 and 112 are fused together and integrated. As shown in Figure 2, the portion of the peripheral seal portion 150 that sandwiches the tab 130 and the tab film 140 is an integrated unit of packaging material 112, tab 130, a pair of tab films 140, and packaging material 111, while the portion of the peripheral seal portion 150 that sandwiches only the pair of tab films 140 is an integrated unit of packaging material 112, a pair of tab films 140, and packaging material 111.

[0022] The packaging materials 111 and 112 are composed of, for example, resin molded articles or films. The resin molded articles referred to here can be manufactured by methods such as injection molding, pressure molding, vacuum molding, and blow molding, and in-mold molding may be performed to impart design or functionality. The type of resin can be polyolefin, polyester, nylon, ABS, etc. The films referred to here are, for example, resin films that can be manufactured by methods such as the inflation method or the T-die method, or such resin films laminated on metal foil. Furthermore, the films referred to here may be stretched or not, and may be single-layer films or multi-layer films. Furthermore, the multi-layer films referred to here may be manufactured by a coating method, by bonding multiple films together with an adhesive, or by a multi-layer extrusion method.

[0023] As described above, the packaging materials 111 and 112 can be composed of various materials, but in this embodiment, they are composed of a laminate film. The laminate film can be a laminate 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 111 and 112, and is typically an insulating resin layer that forms the outer layer of the container 110A. The barrier layer has the function of improving the strength of the packaging materials 111 and 112, as well as preventing at least moisture from entering the energy storage device 100, 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 110A.

[0024] The shape of the container 110A is not particularly limited and can be, for example, a bag-shaped (pouch-shaped). The bag-shaped container can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, etc. However, the container 110A of this embodiment has the shape shown in Figures 1 and 2 and is manufactured by heat-sealing a tray-shaped packaging material 111 and a packaging material 112, which is also molded into a tray shape and placed on top of the packaging material 111, along the outer circumference in a plan view. The packaging material 111 includes an annular flange portion 111A corresponding to the outer circumference in a plan view and a molded portion 111B that is continuous with the inner edge of the flange portion 111A and bulges downward from there. Similarly, the packaging material 112 includes an annular flange portion 112A corresponding to the outer circumference in a plan view and a molded portion 112B that is continuous with the inner edge of the flange portion 112A and bulges upward from there. The packaging materials 111 and 112 are overlapped so that their respective molded portions 111B and 112B bulge in opposite directions. In this state, the flange portion 111A of packaging material 111 and the flange portion 112A of packaging material 112 are heat-sealed together to form a peripheral seal portion 150. The peripheral seal portion 150 extends around the entire outer circumference of the container 110A and is formed in an annular shape. One of the packaging materials 111 or 112 may be in sheet form.

[0025] The energy storage device element 120 comprises at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, an energy storage component such as a lithium-ion battery (secondary battery) or a capacitor. If an abnormality occurs in the energy storage device element 120, gas may be generated in the internal space S1 of the container 110A. If the energy storage device 100 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 110A due to the volatilization of the organic solvent that is the electrolyte and the decomposition of the electrolyte. If the energy storage device 100 is a capacitor, gas may be generated in the internal space S1 of the container 110A due to chemical reactions in the capacitor. The energy storage device 100 may also be an all-solid-state battery, in which case the energy storage device element 120 may include a solid electrolyte that can generate gas. For example, if the solid electrolyte is sulfide-based, hydrogen sulfide gas may be generated.

[0026] Tabs 130 are metal terminals used for inputting and outputting power to the energy storage device element 120. Tabs 130 are arranged separately at the left and right ends of the peripheral seal portion 150 of the container 110A, with one tab constituting the positive terminal and the other constituting the negative terminal. One end of each tab 130 is electrically connected to the electrode (positive or negative) of the energy storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. This configuration of the energy storage device 100 is particularly preferred for use in electric vehicles such as electric vehicles and hybrid vehicles, where multiple energy storage devices 100 are connected in series to operate at high voltage. The mounting positions of the two tabs 130 constituting the positive and negative terminals are not particularly limited and may, for example, be arranged on the same side of the peripheral seal portion 150.

[0027] The metal material that makes up the tab 130 is, for example, aluminum, nickel, copper, etc. If the energy storage device element 120 is a lithium-ion battery, the tab 130 connected to the positive electrode is typically made of aluminum, etc., and the tab 130 connected to the negative electrode is typically made of copper, nickel, etc.

[0028] The left tab 130 is sandwiched between the packaging materials 111 and 112 via the tab film 140 at the left end of the peripheral seal portion 150. The right tab 130 is also sandwiched between the packaging materials 111 and 112 via the tab film 140 at the right end of the peripheral seal portion 150.

[0029] The tab film 140 is a so-called adhesive film and is configured to adhere to both the packaging materials 111 and 112 and the tab 130 (metal). By using the tab film 140, the tab 130 and the innermost layer (heat-fusible resin layer) of the packaging materials 111 and 112 can be fixed together even if they are made of different materials. The tab film 140 is initially fused and fixed to the tab 130 to form an integrated unit, and then the tab 130 with the tab film 140 fixed to it is sandwiched between the packaging materials 111 and 112 and fused together, as shown in Figure 2.

[0030] As the energy storage device 100 operates, gas is generated in the internal space S1 of the container 110A, causing the pressure in the internal space S1 to gradually increase. If the pressure in the internal space S1 rises excessively, the container 110A may rupture, potentially damaging the energy storage device 100. The containment 110 is equipped with a valve structure 10 as a mechanism to prevent such a situation. The valve structure 10 is a gas vent valve for adjusting the pressure in the internal space S1 and is attached, for example, to the peripheral seal portion 150 of the container 110A. The configuration of the valve structure 10 will be described in detail below.

[0031] <1-2. Structure of the valve structure> Figure 3 is a front view of the valve structure 10. The valve structure 10 includes a valve body 20 and a liquid 70 (see Figures 7A and 8). The valve body 20 includes a first body 30, a second body 40, a check valve 50 (see Figures 7A and 8), a sealing member 80, and a lid material 90 (see Figures 7A and 8). In this embodiment, the first body 30 and the second body 40 are arranged in a continuous direction from the inside to the outside of the container 110A (see Figure 1) (from the rear to the front). Figure 4 is a view of the valve structure 10 from the first body 30 side (from the rear). Figure 5 is a view of the valve structure 10 from the second body 40 side (from the front). Figure 6 is a perspective view of the valve structure 10 from the first body 30 side (from the rear).

[0032] Figure 7A is a cross-sectional view taken along the line D7-D7 in Figure 4. Figure 8 is a cross-sectional view taken along the line D8-D8 in Figure 3. As shown in Figures 7A and 8, the check valve 50 is housed in a containment space S2 defined by the first body 30 and the second body 40. The check valve 50 opens when the internal pressure of the container 110A (see Figure 1) rises due to gas generated inside the container 110A, allowing the gas to pass from the inside to the outside of the container 110A. More specifically, the check valve 50 constitutes a relief valve that switches between an open state and a closed state depending on the pressure on its primary side, i.e., the pressure in the internal space S1 (see Figure 1). A passage LA is formed in the containment space S2 inside the valve body 20. The passage LA is a passage that connects the inside and outside of the container 110A, and has an inlet 20A facing the internal space S1 of the container 110A and an outlet 20B facing the external space.

[0033] The check valve 50 is positioned to block the passage LA when it is closed. When the pressure in the internal space S1 rises due to gas generated in the internal space S1, the check valve 50 opens, allowing the gas to pass from its primary side to its secondary side, i.e., from the internal space S1 to the external space. When it is closed, the check valve 50 seals the internal space S1 from the external space.

[0034] The first body 30 includes a mounting portion 31 and a connecting portion 32. The mounting portion 31 is a portion for attaching the valve structure 10 to the container 110A. The mounting portion 31 is heat-sealed together with the packaging materials 111 and 112 via a heat-sealable film 60 (see Figure 1) when the container 110A is formed. This heat sealing fuses the outer surface of the mounting portion 31 with the packaging materials 111 and 112 via the heat-sealable film 60, and the mounting portion 31 is fixed to the peripheral sealing portion 150 in such a manner that it is sandwiched between the packaging materials 111 and 112 (see Figure 2).

[0035] The connecting portion 32 is positioned outside the peripheral seal portion 150 and is not sandwiched between the packaging materials 111 and 112 (see Figures 1 and 2). Furthermore, the second body 40, which is positioned even further outside than the connecting portion 32, is also positioned outside the peripheral seal portion 150 and is not sandwiched between the packaging materials 111 and 112. As a result, the risk of the check valve 50, which is held in the second body 40, being damaged by deformation or the like due to the heat generated when the mounting portion 31 is attached to the container 110A by heat sealing is reduced.

[0036] The mounting portion 31, the connecting portion 32, and the second body 40 extend coaxially with each other. The mounting portion 31, the connecting portion 32, and the second body 40 share a common central axis C1. The mounting portion 31 has a first ventilation passage LX, the second body 40 has a second ventilation passage LY, and the connecting portion 32 has a third ventilation passage LZ. These ventilation passages LX to LZ also extend coaxially with respect to the central axis C1. In this embodiment, the inlet 20A and outlet 20B are located on the front-rear end faces of the valve body 20, rather than on the outer circumferential surface, and in particular, the central axis C1, which extends linearly in the front-rear direction, passes through the centers of the inlet 20A and outlet 20B. Although not limited to this, the cross-sections perpendicular to the central axis C1 of the ventilation passages LX to LZ are circular. The ventilation passages LX to LZ communicate with each other and together constitute a passage LA. The third ventilation passage LZ is located further outside the container 110A than the first ventilation passage LX. The second ventilation passage LY is located even further outside the container 110A than the third ventilation passage LZ.

[0037] As shown in Figures 4 and 6, the mounting portion 31 has a non-circular shape when viewed along the direction in which the central axis C1 extends. More specifically, the mounting portion 31 has a first wing-shaped portion 31A that is thinner towards the left from the center in the left-right direction, and a second wing-shaped portion 31B that is thinner towards the right, when viewed along the direction in which the central axis C1 extends. Therefore, in this embodiment, the mounting portion 31 becomes thicker as it approaches the center in the width direction (left-right direction) of the energy storage device 100, and thinner as it approaches the ends in the width direction (left-right direction) of the energy storage device 100.

[0038] In this embodiment, since the first wing-shaped portion 31A and the second wing-shaped portion 31B are formed, the outer circumferential surface of the mounting portion 31 forms a smooth curved surface in both the lower half covered by the packaging material 111 and the upper half covered by the packaging material 112. Furthermore, compared to, for example, the case in which the mounting portion 31 is formed in a cylindrical shape, the first wing-shaped portion 31A and the second wing-shaped portion 31B make the change in the vertical thickness of the energy storage device 100 smoother at the point where the peripheral seal portion 150 transitions from the portion where the mounting portion 31 is not sandwiched to the portion where the mounting portion 31 is sandwiched. As a result, no undue force is applied to the packaging materials 111 and 112 in the peripheral seal portion 150 around the position where the mounting portion 31 is attached. Therefore, the mounting portion 31 can be firmly fixed to the peripheral seal portion 150 via the heat-seal film 60.

[0039] The external shape of the connecting portion 32 is generally like a cylinder with a central axis C1 as its central axis, with a portion of it cut out. More specifically, the external shape of the connecting portion 32 is generally like a cylinder with a central axis C1 as its central axis, with a portion cut out by a plane at a certain distance from the central axis C1, and further cut out by a plane at a position symmetrical to the said plane with respect to the central axis C1. Therefore, the connecting portion 32 has a pair of planes, a first plane 32A and a second plane 32B. The first plane 32A and the second plane 32B are parallel to each other (including cases where they are substantially parallel; the same applies hereinafter). The first plane 32A and the second plane 32B are parallel to the direction in which the central axis C1 extends (including cases where they are substantially parallel; the same applies hereinafter). In this embodiment, the first plane 32A and the second plane 32B are also parallel to the direction in which the peripheral seal portion 150 extends (including cases where they are substantially parallel; the same applies hereinafter). The outer circumferential surface of the connecting portion 32 is composed of a first plane 32A and a second plane 32B, and curved surfaces 32C and 32D connecting the first plane 32A and the second plane 32B. When viewed along the direction in which the central axis C1 extends, the curved surfaces 32C and 32D are arc-shaped with respect to the central axis C1 and overlap the outer shape of the second body 40. The connecting portion 32 as described above can be formed by cutting the outer circumferential surface of a cylindrical member so that the first plane 32A and the second plane 32B are formed. Because the outer shape of the connecting portion 32 is configured in this way, the valve structure 10 is easy to grip. This makes it easy to transport the valve structure 10 to the processing position and to fix the valve structure 10 at the processing position. For this reason, the valve structure 10 can be easily attached to the container 110A.

[0040] The second body 40 is cylindrical and, together with the first body 30, defines a housing space S2 for housing the check valve 50. The first body 30 and the second body 40 are assembled with the check valve 50 housed in the housing space S2. The manner in which the first body 30 and the second body 40 are joined is, for example, at least one of adhesive bonding, screw structure bonding, and interlocking of protrusions and recesses. In this embodiment, the first body 30 and the second body 40 are joined by the interlocking of a male thread 32X (see Figure 7A) formed on the outer surface of the connecting portion 32 of the first body 30 and a female thread 40A (see Figure 7A) formed on the inner surface of the second body 40, as well as by an adhesive applied to the male thread 32X and the female thread 40A. The material of the adhesive is not particularly limited, but can be composed of acid-modified polyolefin and epoxy resin. Such adhesives are superior to, for example, those made of modified silicone resin, in that they can suppress the deterioration of adhesive performance due to the electrolyte contained in the container 110A. Any means can be used for bonding the first body 30 and the second body 40. Therefore, in this embodiment, the structure relating to the engagement between the male screw 32X and the female screw 40A, and at least one of the adhesives, may be omitted.

[0041] As described above, in this embodiment, the external shapes of the mounting portion 31, the connecting portion 32, and the second body 40 are all different when viewed along the direction in which the central axis C1 extends, according to the role assigned to each portion.

[0042] The second body 40 holds the main structural components necessary for the valve structure 10 to function as a gas venting valve. In this embodiment, the check valve 50 has a spring 51, a valve body 52, and a valve seat 53 as a valve mechanism housed in the second air passage LY inside the second body 40. The spring 51, valve body 52, and valve seat 53 are arranged in this order from the outlet 20B to the inlet 20A within the second air passage LY. In this embodiment, as shown in Figures 7A and 8, the first body 30 and the valve seat 53 are configured as separate parts, but they may be configured as an integrated unit.

[0043] The valve seat 53 receives the valve body 52, which is biased from the outside by the spring 51, and at this time, the closed state of the valve structure 10 is formed. The spring 51 is, for example, a coil spring, but is not limited to this, and can also be a leaf spring, for example. In this embodiment, the valve seat 53 is cylindrical with a central axis C1 as its central axis, and has a top surface 53A that defines the front end face in the front-rear direction, and a bottom surface 53B that defines the rear end face. The valve body 52 is, for example, ball-shaped. A part of the surface of the valve body 52 is received by the top surface 53A of the valve seat 53 and contacts the top surface 53A when the check valve 50 is in the closed state. The spring 51 extends spirally with a central axis C1 as its central axis. The spring 51 is connected to the valve body 52.

[0044] The valve seat 53 and the first body 30 can be bonded together, for example, with an adhesive. The material of the adhesive is not particularly limited, but a preferred example when the valve seat 53 is made of fluororubber and the first body 30 is made of a metal such as aluminum is the same adhesive as the one exemplified when joining the first body 30 and the second body 40. Furthermore, from the viewpoint of preventing the valve structure 10 from opening, adhesive can be applied to various other locations as appropriate. For example, adhesive can be applied between the rear end face 41 of the second body 40 and the front end face 32E of the connecting portion 32.

[0045] The mounting portion 31 is fixed to the peripheral seal portion 150 so that gas generated in the internal space S1 of the container 110A flows into the first ventilation passage LX. That is, the first ventilation passage LX inside the mounting portion 31 is in communication with the internal space S1 of the container 110A. Therefore, when the pressure in the internal space S1, i.e., the pressure in the space on the primary side of the check valve 50, reaches a predetermined pressure, the gas that flows out of the internal space S1 and passes through the first ventilation passage LX and the third ventilation passage LZ pushes the valve body 52 toward the outlet 20B. When the valve body 52 is pushed and separates from the valve seat 53, the spring 51 deforms, causing the valve body 52 to move toward the outlet 20B, and the check valve 50 is opened. In this open state, the gas generated in the internal space S1 flows out toward the outlet 20B through the gap formed between the valve body 52 and the valve seat 53 and is discharged into the outside space. In this way, when the gas in the internal space S1 is discharged from the passage LA, the pressure in the internal space S1 that pushes the valve body 52 toward the outlet 20B weakens, and the force of the spring 51 biasing the valve body 52 toward the inlet 20A becomes greater than this weakening force. As a result, the shape of the spring 51 is restored, and the check valve 50 is closed again.

[0046] When the check valve 50 is closed, it can prevent air from entering the internal space S1 of the container 110A from the outside space. After the check valve 50 has opened once, the internal space S1 is maintained at a relatively high pressure equal to or greater than atmospheric pressure, so air is unlikely to enter the internal space S1. The valve structure 10 effectively prevents air from entering the internal space S1 with the check valve 50 as described above, and can prevent deterioration of the energy storage device element 120 due to moisture contained therein. Furthermore, even when the check valve 50 is open, air is unlikely to enter the internal space S1. This is because, when it is open, the pressure on the primary side of the check valve 50 is higher than, or equal to, the pressure on its secondary side.

[0047] The liquid 70 shown in Figures 7A and 8 is placed in the containment space S2. The hatched areas shown in Figures 7A and 8 are examples of the areas where the liquid 70 is present.

[0048] Liquid 70 enters the internal space S1 (see Figure 1) atmosphere To prevent intrusion, the valve body 52 and valve seat 53 are positioned in contact. The type of liquid 70 can be arbitrarily selected. In this embodiment, the liquid 70 is liquid paraffin. Liquid oils such as silicone oil or ionic liquids can also be used as the liquid 70. In a preferred example, the liquid 70 preferably exists as a liquid under the normal operating environment of the energy storage device 100. From this viewpoint, the melting point of the liquid 70 is preferably 10°C or lower, and more preferably 0°C or lower. Similarly, the boiling point of the liquid 70 is preferably 150°C or higher. In this embodiment, the temperatures exemplified as the melting point and boiling point of the liquid 70 are the temperatures under the normal operating environment of the energy storage device 100. The energy storage device 100 of this embodiment is used, for example, under atmospheric pressure or vacuum. The energy storage device 100 may also be used in environments other than under atmospheric pressure or vacuum. The melting point of the liquid is the melting point measured according to "JIS K0064-1992 Method for Measuring the Melting Point and Melting Range of Chemical Products". The boiling point of a liquid is the boiling point measured according to "JIS K0066-1992 Distillation Test Method for Chemical Products". When the energy storage device 100 is used under atmospheric pressure, the measurement conditions for the melting point and boiling point are normal temperature and humidity as specified in "JIS Z8703-1983".

[0049] The viscosity of liquid 70 can be arbitrarily selected. In a preferred example, the viscosity of the liquid is determined based on the viewpoint of suitable gas permeability and handling. A preferred example of the maximum viscosity of liquid 70 is 2000 mPa·s. When the viscosity of liquid 70 is 2000 mPa·s or less, the gas can be suitably permeated. A more preferred example of the maximum viscosity of liquid 70 is 500 mPa·s. A more preferred example of the maximum viscosity of liquid 70 is 100 mPa·s. A preferred example of the minimum viscosity of liquid 70 is 0.1 mPa·s. When the viscosity of liquid 70 is 0.1 mPa·s or more, it can be suitably handled. A more preferred example of the minimum viscosity of liquid 70 is 0.5 mPa·s. A more preferred example of the minimum viscosity of liquid 70 is 1.0 mPa·s. A preferred range for the viscosity of liquid 70 is 0.1 mPa·s to 2000 mPas. A more preferred range for the viscosity of liquid 70 is 0.5 mPa·s to 500 mPas. A further preferred range for the viscosity of liquid 70 is 1.0 mPa·s to 100 mPas. Note that the viscosity of liquid 70 is the viscosity at 23°C. Furthermore, if liquid 70 is crude oil or petroleum, the viscosity of liquid 70 is calculated by multiplying the kinematic viscosity, measured according to "JIS K2283 Crude oil and petroleum products - Kinematic viscosity test method and viscosity index calculation method," by the density. If liquid 70 is not crude oil or petroleum, the viscosity of liquid 70 is measured according to "JIS Z8803 Method for measuring the viscosity of liquids."

[0050] The specific arrangement of the liquid 70 can be arbitrarily selected as long as the liquid 70 is in contact with the valve body 52 and the valve seat 53. In this embodiment, the liquid 70 is filled into a predetermined range of the containment space S2. The liquid 70 is filled, for example, from at least one of the inlet 20A and the outlet 20B after the first body 30 and the second body 40 have been assembled. According to this embodiment, when the check valve 50 is in the open state, the gas generated in the internal space S1 (see Figure 1) flows out from the gap formed between the valve body 52 and the valve seat 53. The flowing gas passes through the liquid 70 in a foamy state, and after passing through the liquid 70, flows out towards the outlet 20B. On the other hand, if air and the moisture contained therein enter the valve structure 10 from the outlet 20B, the liquid 70 prevents the moisture from entering the inside of the container 110A beyond the check valve 50. Therefore, the entry of air and the moisture contained therein into the container 110A is suppressed. As shown in Figure 11, the liquid 70 only needs to adhere to the portion of the surface of the valve body 52 that contacts the valve seat 53, and the portion of the surface of the valve seat 53 that contacts the valve body 52, when the check valve 50 is closed. Such a configuration of liquid 70 can be formed, for example, by injecting air from the inlet 20A to blow away the liquid 70, as shown in Figure 7A. In the configuration of liquid 70 shown in Figure 11, the liquid 70 forms a film on the portion of the surface of the valve body 52 that contacts the valve seat 53, and the portion of the surface of the valve seat 53 that contacts the valve body 52, when the check valve 50 is closed. When the check valve 50 is open, the gas generated in the internal space S1 passes through the film of liquid 70 in a bubble-like manner, or breaks through the film of liquid 70 and flows out towards the outlet 20B. When the gas penetrates the film of liquid 70, the check valve 50 moves from an open state to a closed state, causing the valve body 52 and the valve seat 53 to come into contact, and the film of liquid 70 is regenerated.

[0051] The materials that make up each part of the valve structure 10 are not particularly limited. As a preferred example, the valve body 52 may be made of a fluororesin such as polytetrafluoroethylene (PTFE), and the valve seat 53 may be made of a fluororubber such as vinylidene fluoride (FKM). Furthermore, the spring 51 may be made of metal such as stainless steel, and the mounting part 31, the second body 40, and the connecting part 32 may be made of metal such as aluminum alloy, stainless steel, steel plate, or titanium. The second body 40 is preferably made of metal because it plays a role in protecting the check valve 50. The valve body 52 may also be made of metal such as stainless steel, or of a fluororubber such as FKM. When the valve body 52 is made of a fluororubber such as FKM, the valve seat 53 is preferably made of a fluororesin such as PTFE.

[0052] The material constituting the mounting portion 31 and the material constituting the second body 40 may be the same material or different materials. If the material constituting the mounting portion 31 is, for example, resin, the outer surface of the mounting portion 31 and the packaging materials 111 and 112 are fused and joined, so the heat-sealing film 60 described later is unnecessary. This simplifies the configuration of the energy storage device 100. The resin constituting the mounting portion 31 may be, for example, a fluororesin, polyester resin, polyimide resin, polycarbonate resin, polyolefin resin, or acrylic resin.

[0053] Preferably, the melting point of the material constituting the second body 40 is higher than the melting point of the material constituting the mounting portion 31. With this configuration, even if pressure and heat are applied to the mounting portion 31 when the opposing heat-sealable resin layers of the packaging materials 111 and 112 are fused together, the melting point of the material constituting the second body 40 is higher than the melting point of the material constituting the mounting portion 31, thus preventing the check valve 50 from deforming or malfunctioning due to heat.

[0054] In the valve structure 10, the entirety of the first body 30 and the second body 40 may be made of metal or resin. In the valve structure 10, the entirety of the first body 30 and the second body 40 may be made of a mixed material of metal and resin. In the valve structure 10, the first body 30 may be made of a mixed material of metal and resin, and the second body 40 may be made of metal. In the valve structure 10, the first body 30 may be made of resin, and the second body 40 may be made of metal. For example, in the valve structure 10, when the first body 30 is made of a mixed material of metal and resin, the outer circumferential surface of the mounting portion 31 and the packaging materials 111 and 112 are fused and joined, so the heat-sealing film 60 described later is unnecessary. In addition, the first wing-shaped portion 31A and the second wing-shaped portion 31B of the mounting portion 31 can be easily processed. Furthermore, the mounting portion 31 and the packaging materials 111 and 112 can be heat-sealed with high precision. The resins constituting the first body 30 and the second body 40 include, in addition to the resin constituting the mounting portion 31 described above, olefin-based resins. Olefin-based resins include, for example, acid-modified polypropylene, or a resin obtained by two-color molding of acid-modified polypropylene and polypropylene. When the resin material is extruded onto a metal material, it is preferable to apply a coating of a corrosion inhibitor, described later, to the surface of the portion made of the metal material to form a corrosion-preventive coating layer.

[0055] The heat-sealable film 60 shown in Figure 1, etc., is configured to adhere to both the valve structure 10 and the packaging materials 111 and 112 of the container 110A by heat sealing. The heat-sealable film 60 is fused to the mounting portion 31 of the first body 30 before the first body 30 and the second body 40 are assembled while the check valve 50 is housed in the housing space S2 (see Figure 7A). The heat-sealable film 60 is fused to the mounting portion 31 so as to cover most of the surface of the mounting portion 31. Various known adhesive films can be used as the heat-sealable film 60. The heat-sealable film 60 may be, for example, a single-layer film of maleic anhydride-modified polypropylene (PPa), or a multi-layer laminated film of PPa, polyethylene naphthalate (PEN), and PPa. Alternatively, it may be a multi-layer laminated film of PPa, polypropylene (PP), and PPa. In addition, metal-bondable resins such as ionomer resin, modified polyethylene, and EVA can be used instead of the PPa resin mentioned above. In this embodiment, the heat-sealable film 60 employs a three-layer laminated film containing a core material made of PPa / polyester fiber / PPA. Various known materials other than the polyester fiber mentioned above can be used as the core material. For example, the core material may be a polyester film such as PEN, polyethylene terephthalate, or polybutylene terephthalate, or it may be a polyamide fiber or a carbon fiber.

[0056] Furthermore, it is preferable to apply a corrosion inhibitor coating to the surface of the mounting portion 31, particularly from the viewpoint of electrolyte resistance, to form a corrosion-preventive coating layer. This is especially true when the mounting portion 31 is made of a metal such as aluminum, but it may also apply when the mounting portion 31 is made of other materials. Such a coating can be applied by immersing the mounting portion 31 in a liquid corrosion inhibitor and then performing a baking treatment. This allows a corrosion-preventive coating layer to be formed on the outer surface of the mounting portion 31 and on the inner surface facing the first ventilation passage LX, thereby preventing corrosion of the outer surface due to gas generated from the energy storage device element 120 and corrosion of the inner surface due to gas passing through the first ventilation passage LX. Furthermore, particularly from the viewpoint of electrolyte resistance, a similar coating may be applied not only to the mounting portion 31 but also to the surfaces of the connecting portion 32, the second body 40, and the check valve 50 to form a corrosion-preventive coating layer. When applying a corrosion inhibitor coating to the surfaces of the connecting portion 32, the second body 40, and the check valve 50, it is particularly preferable to form the corrosion inhibitor coating layer in a predetermined area including the male thread 32X of the connecting portion 32, the female thread 40A of the second body 40, the valve body 52, and the area where the second body 40 and the valve seat 53 come into contact. However, from the viewpoint of suppressing deterioration of the adhesive performance between the mounting portion 31 and the packaging materials 111 and 112 due to the electrolyte, it is particularly beneficial to apply such a coating to the mounting portion 31. The material of the corrosion inhibitor is not particularly limited, but an acid-resistant material is preferred, and the corrosion inhibitor coating layer can be formed by chromate treatment of chromium acid or chromate treatment of phosphate, etc.

[0057] The sealing member 80 is attached to the second body 40 so as to close the outlet 20B. This prevents, for example, liquid 70 from leaking out of the outlet 20B during transport of the valve structure 10, and prevents foreign matter from entering the inside of the valve structure 10 from the outlet 20B. When the valve structure 10 is attached to the container 110A, the sealing member 80 is peeled off from the second body 40. The sealing member 80 shown in Figure 7B includes, for example, a surface layer 81 that closes the outlet 20B, and a base layer 82 laminated on the surface layer 81. The sealing member 80 may be an adhesive containing acrylic resin, or it may be a single-layer structure consisting only of the surface layer 81.

[0058] The material constituting the surface layer 81 preferably includes, for example, at least one of polyolefin and elastomer. When polyolefin is present on the surface of the surface layer 81, the sealing member 80 can be easily peeled off from the second body 40 when the valve structure 10 is in use. The polyolefin is, for example, polyethylene or polypropylene. When the material constituting the surface layer 81 includes an elastomer, the surface layer 81 is adhesive, so the sealing member 80 can be easily positioned relative to the outlet 20B. The elastomer is, for example, a thermoplastic elastomer.

[0059] The base layer 82 includes, for example, a first base layer 82A laminated on the surface layer 81, and a second base layer 82B laminated on the first base layer 82A. The material constituting the first base layer 82A preferably includes a metal such as an aluminum alloy, from the viewpoint of improving water vapor barrier properties and airtightness. When the material constituting the first base layer 82A includes a metal, the sealing member 80 as a whole has tension and can be easily peeled off from the second body 40. The second base layer 82B is laminated on the first base layer 82A via, for example, an adhesive. The material constituting the second base layer 82B includes, for example, polyethylene terephthalate.

[0060] The lid material 90 is, for example, 10 -2 μm~10 0The device is composed of a PTFE (PolyTetraFluoroEthylene) membrane having a pore diameter of μm, which selectively permeates only gas and does not allow organic solvents and liquid 70 contained in the energy storage device element 120 to pass through. Because the PTFE membrane is a soft material, if its strength is insufficient, a mesh made of polypropylene and polyester, or a nonwoven fabric, may be integrally molded with the PTFE membrane to reinforce it as the cover material 90. The material constituting the cover material 90 may also be, for example, a metal mesh, a synthetic resin mesh, or a nonwoven fabric. The cover material 90 includes a first cover material 91 arranged on the primary side of the check valve 50 and a second cover material 92 arranged on the secondary side of the check valve 50.

[0061] The first cover material 91 prevents organic solvent contained in the energy storage device element 120 (see Figure 2) from passing through passage LA and opening the check valve 50, thereby preventing it from flowing out of the valve body 20. The position in the valve body 20 where the first cover material 91 is placed can be arbitrarily selected as long as it is on the primary side of the check valve 50. In this embodiment, the first cover material 91 is placed in passage LA near the bottom surface 53B of the valve seat 53. The first cover material 91 may also be placed in passage LA near the inlet 20A, or at any location between the bottom surface 53B of the valve seat 53 and the inlet 20A.

[0062] The second cover material 92 prevents the liquid 70 from leaking out of the outlet 20B when the sealing member 80 is detached, for example, when the valve structure 10 is in use. The second cover material 92 is positioned, for example, near the outlet 20B. The second cover material 92 may be positioned at any position between the liquid level of the liquid 70 and the outlet 20B.

[0063] [2. Second Embodiment] In the second embodiment, the configuration of the valve structure 10 differs from that of the first embodiment. Other configurations are basically the same as in the first embodiment. In the following, components identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The description will focus on the parts that differ from the first embodiment.

[0064] Figure 9 is a front view of the valve structure 200 of the second embodiment. Figure 10 is a cross-sectional view along the line D10-D10 in Figure 9. The second body 40 of this embodiment is configured to hold a plurality of check valves 50. In this embodiment, the second body 40 holds two check valves 50. Hereinafter, in order to distinguish between the two check valves 50, the check valve 50 located closer to the inlet 20A may be referred to as check valve 210, and the check valve 50 located closer to the outlet 20B may be referred to as check valve 220.

[0065] The check valves 210 and 220 are arranged along the direction in which the passage LA extends, with check valve 220 positioned on the secondary side (external side) of check valve 210. When the check valves 210 and 220 open, the passage LA can discharge the gas generated in the internal space S1 (see Figure 1) to the outside of the container 110A. Note that the check valves 210 and 220 do not necessarily open simultaneously, and often open at different times.

[0066] The check valves 210 and 220 are arranged to close the passage LA at different positions along the direction in which the passage LA extends, when in the closed state. In this embodiment, the body portion (valve casing) included in the check valves 210 and 220 is made up of a second body 40, and the valve mechanism included in the check valves 210 and 220 is located inside the second body 40. The space included in the passage LA that is located on the secondary side (external side) of the check valve 210 and on the primary side (internal side) of the check valve 220 is called the intervalve space S3. The check valve 210 opens when the pressure in the internal space S1 rises due to gas generated in the internal space S1, allowing the gas to pass from its primary side to its secondary side, i.e., into the intervalve space S3. When the check valve 210 opens and gas generated in the internal space S1 flows into the intervalve space S3, the pressure in the intervalve space S3 rises. The check valve 220 opens when the pressure in the valve space S3 rises in this manner, allowing the gas to pass from its primary side to its secondary side, i.e., to the outside space. The valve structure 200 seals the internal space S1 from the outside space when either the check valve 210 or 220 is closed.

[0067] When the pressure in the internal space S1, that is, the pressure in the space on the primary side of the check valve 210, reaches a predetermined pressure, the gas that flows out of the internal space S1 and passes through the first ventilation passage LX and the third ventilation passage LZ pushes the valve body 52 toward the check valve 220. When the valve body 52 is pushed and separates from the valve seat 53, the spring 51 deforms, causing the valve body 52 to move toward the check valve 220, and the check valve 210 opens. In this open state, the gas generated in the internal space S1 flows out into the intervalve space S3 through the gap formed between the valve body 52 and the valve seat 53. In this way, when the gas in the internal space S1 is discharged to the secondary side of the check valve 210, the pressure on the internal space S1 side that pushes the valve body 52 toward the check valve 220 weakens, and the force of the spring 51 biasing the valve body 52 toward the inlet 20A becomes greater than this weakened pressure. As a result, the shape of the spring 51 is restored, and the closed state of the check valve 210 is formed again.

[0068] When the check valve 210 opens and the pressure in the intervalve space S3 included in the second ventilation passage LY, that is, the pressure in the space on the primary side of the check valve 220, reaches a predetermined pressure, the gas in the intervalve space S3 pushes the valve body 52 toward the outlet 20B. When the valve body 52 is pushed and separates from the valve seat 53, the spring 51 deforms, causing the valve body 52 to move toward the outlet 20B, and the check valve 220 opens. In this open state, the gas contained in the intervalve space S3 flows out toward the outlet 20B through the gap formed between the valve body 52 and the valve seat 53, and is discharged into the outside space from the outlet 20B. In this way, when the gas in the intervalve space S3 is discharged from the passage LA, the pressure on the intervalve space S3 side that pushes the valve body 52 toward the outlet 20B weakens, and the force of the spring 51 biasing the valve body 52 toward the check valve 210 becomes greater than this weakened pressure. As a result, the shape of the spring 51 is restored, and the closed state of the check valve 220 is formed again.

[0069] Each of the check valves 210 and 220, when closed, can prevent air from entering the internal space S1 of the container 110A from the external space. Furthermore, for air to enter the internal space S1 from the external space, it would have to flow back through multiple check valves 210 and 220, making such entry unlikely. Additionally, once check valve 210 opens, the intervalve space S3 is maintained at a relatively high pressure equal to or greater than atmospheric pressure, making it difficult for air to even enter the intervalve space S3 from the external space. Therefore, the valve structure 200, with its multi-stage arrangement of check valves 210 and 220 along the passage LA, effectively prevents air from entering the internal space S1, thereby preventing deterioration of the energy storage device element 120 due to moisture and other contaminants contained within.

[0070] Even when the check valves 210 and 220 are open, atmospheric air is unlikely to enter the internal space S1. This is because, in the open state, the pressure on the primary side of each of the check valves 210 and 220 is maintained to be higher than or equal to the pressure on its secondary side.

[0071] The opening pressures of the check valves 210 and 220 can be set as appropriate. The opening pressure of check valve 210 may be (i) equal to the opening pressure of check valve 220, (ii) lower than the opening pressure of check valve 220, or (iii) higher than the opening pressure of check valve 220. However, (i) and (ii) are preferred from the following viewpoints. In case (ii), the pressure in the internal space S1 can be maintained at a higher level, so that the pressure difference between the internal space S1 and the external space prevents the air from the external space from entering the internal space S1 more effectively. In case (i), the pressure in the internal space S1 can be maintained at a relatively high level, while the manufacturing of check valves 210 and 220 becomes easier, and there is an advantage that, for example, there is no chance of mixing up check valves 210 and 220. For example, the opening pressures of both check valves 210 and 220 can be set to 0.05 MPa. The overall opening pressure of the valve structure 200 is the sum of the opening pressures of the check valves 210 and 220, and in this example, it is 0.1 MPa. The opening pressure is the pressure difference between the primary side pressure and the secondary side pressure.

[0072] It is preferable to fill the valve space S3 with gas so that the pressure is higher than atmospheric pressure before or immediately after attaching the valve structure 200 to the container 110A. In this case, the valve space S3 is kept at a pressure higher than atmospheric pressure from immediately after the energy storage device 100 is manufactured, that is, even before the check valve 210 is opened. Therefore, the entry of air from the outside space into the valve space S3, and consequently into the internal space S1, is more effectively prevented. If, after the manufacture of the valve structure 200, the pressure on the primary side of the check valve 210 is increased to perform an opening inspection of the check valves 210 and 220, this inspection can also serve as the process of filling the valve space S3 with gas. Furthermore, it is preferable that the gas filled into the valve space S3 is an inert gas such as argon. When filling the valve space S3 with gas by performing an opening inspection of the check valves 210 and 220, it is sufficient to use an inert gas for the opening inspection. In this case, even the slight intrusion of gas into the internal space S1 prevents the energy storage device element 120 from degrading.

[0073] Liquid 70 enters the internal space S1 (see Figure 1) atmosphere To prevent the intrusion of liquid, the liquid 70 is positioned to contact the valve body 52 and valve seat 53 of the check valve 210. The specific arrangement of the liquid 70 can be arbitrarily selected as long as the liquid 70 is in contact with the valve body 52 and valve seat 53. In this embodiment, the liquid 70 is filled to a predetermined range of the intervalve space S3. The liquid 70 may be filled, for example, before assembling the check valve 210 and the check valve 220, or it may be filled from the inlet 20A after assembling the check valve 210 and the check valve 220. Alternatively, the liquid 70 may be filled from the outlet 20B before positioning the spring 51 and valve body 52 of the check valve 220. Note that, in the closed state of the check valve 210, the liquid 70 should at least adhere to the portion of the surface of the valve body 52 that contacts the valve seat 53, and to the portion of the surface of the valve seat 53 that contacts the valve body 52. Such a configuration of liquid 70 can be formed, for example, by injecting air from the inlet 20A and blowing away the liquid 70 in the state shown in Figure 10.

[0074] According to this embodiment, when the check valve 50 is open, the gas generated in the internal space S1 (see Figure 1) flows out through the gap formed between the valve body 52 and the valve seat 53. The flowing gas passes through the liquid 70 in a foamy state, and after passing through the liquid 70, flows out towards the outlet 20B. On the other hand, if air and the moisture contained therein enter the valve structure 200 from the outlet 20B, the liquid 70 prevents the moisture from entering the inside of the container 110A beyond the check valve 210. Therefore, the entry of air and the moisture contained therein into the container 110A is suppressed.

[0075] <3. Variant> The embodiments described above are illustrative of possible forms of the valve structure for energy storage devices and energy storage devices according to the present invention, and are not intended to limit their forms. The valve structure for energy storage devices and energy storage devices according to the present invention may take forms different from those illustrated in each embodiment. One example is a form in which a part of the configuration of each embodiment is replaced, modified, or omitted, or a form in which a new configuration is added to each embodiment. Several examples of modifications of each embodiment are shown below. The gist of the following modifications is applicable to the second embodiment as well as the first embodiment.

[0076] <3-1> The configuration of the check valve 50 is not limited to those shown in each embodiment and can be changed as desired. For example, the check valve 50 can be configured as a different type of check valve that allows for repeated gas venting, such as a poppet type, duckbill type, umbrella type, or diaphragm type, rather than the ball spring type described above.

[0077] <3-2> In the second embodiment, instead of the check valve 210 or the check valve 220, a rupture valve capable of one-time gas release may be used, that is, a rupture valve configured to rupture when the internal pressure of the container 110A rises due to gas generated inside the container 110A. In this modified example, considering that the liquid 70 is filled from the inlet 20A, it is preferable to use a rupture valve instead of the check valve 220.

[0078] <3-3> In the second embodiment, as shown in Figure 12, the liquid 70 may be arranged to be in contact with the valve body 52 and valve seat 53 of the check valve 220. The specific arrangement of the liquid 70 can be arbitrarily selected as long as the liquid 70 is in contact with the valve body 52 and valve seat 53 of the check valve 220. In this modified example, the liquid 70 fills a predetermined range of the containment space S2. In this modified example, the liquid 70 arranged to be in contact with the valve body 52 and valve seat 53 of the check valve 210 can also be omitted.

[0079] <3-4> In the second embodiment shown in Figure 10 and the modified version of the second embodiment shown in Figure 12, the first cover material 91 may be positioned on the primary side of the check valve 220 and above the liquid level of the liquid 70 that contacts the valve body 52 and valve seat 53 of the check valve 210. According to this modified version, the opening of the check valve 220 is suppressed by the liquid 70 that contacts the valve body 52 and valve seat 53 of the check valve 210, and the organic solvent contained in the energy storage device element 120 (see Figure 2).

[0080] <3-5> In the second embodiment, the valve structure 200 had two check valves 210, 220, but it may have three or more check valves arranged along the direction in which the passage LA extends. These three or more check valves, when closed, block the passage LA at different locations within the passage LA.

[0081] <3-6> The configuration of the valve body 52 is not limited to those shown in each embodiment and can be arbitrarily changed. Figure 13 is a cross-sectional view of a valve structure 10 having a modified valve body 252. The valve body 252 is inverted T-shaped and has a disc-shaped portion 252A and a cylindrical shaft portion 252B that is continuous with the front end face 252AX of the disc-shaped portion 252A in the front-rear direction and extends forward from the center of the end face 252AX. Both the disc-shaped portion 252A and the shaft portion 252B extend with a central axis C1 as their central axis. The bottom surface 252AY, which is the rear end face of the disc-shaped portion 252A in the front-rear direction, is received by the top surface 253A of the valve seat 253 and contacts the top surface 253A when the check valve 250 is closed. The shaft portion 252B of the valve body 252 is inserted into the space inside the spring 51, thereby connecting the valve body 252 and the spring 51.

[0082] <3-7> The configuration of the peripheral seal portion 150 is not limited to those shown in each embodiment and can be arbitrarily changed. As shown in Figure 14, the peripheral seal portion 150 may have inclined seal portions 151 and 152 in which the seal width narrows as it approaches the valve structure 10. As shown in Figure 15, the peripheral seal portion 150 may have inclined seal portions 251X and 252X that are inclined to approach the valve seal portion 253X in which the valve structure 10 and the packaging materials 111 and 112 are sealed. As shown in Figure 16, the peripheral seal portion 150 may have stepped inclined seal portions 351 and 352 that are inclined to approach the valve seal portion 353 in which the valve structure 10 and the packaging materials 111 and 112 are sealed. As shown in Figure 17, the peripheral seal portion 150 may have inclined seal portions 451 and 452 that are inclined to approach the valve structure 10 and have a substantially constant seal width. According to the modified examples shown in Figures 14 to 17, the gas generated in the internal space S1 is guided toward the valve structure 10, so that the gas can be effectively discharged from the valve structure 10.

[0083] <3-8> Although container 110A is constructed by heat-sealing packaging material 111 and packaging material 112, container 110A may also be constructed by folding a single sheet of packaging material and heat-sealing the periphery.

[0084] <3-9> The container 110A may be composed of the packaging materials 111 and 112 as described above, but it may also be made of other materials, such as a metal can. [Explanation of Symbols]

[0085] 10, 200: Valve structure for energy storage devices 20B:Exit 50: Check valve 52, 252: Valve body 53: Alveolar seat 70:Liquid 80: Sealing material 90: Lid material 100: Energy storage devices 110A: Container 120: Energy storage device element LA: Passageway

Claims

1. A passage that connects the inside and outside of the container housing the energy storage device element, A check valve is provided, which is positioned to block the passage and opens when the internal pressure of the container rises due to gas generated inside the container, allowing the gas to pass from the inside to the outside of the container. A first body including a mounting portion that is joined to the container, It comprises a second body connected to the first body and housing the check valve, The aforementioned check valve includes a valve seat and a valve body, In order to prevent air from entering the container, the container is provided with a liquid that is in contact with the valve seat and the valve body, The melting point of the material constituting the second body is higher than the melting point of the material constituting the mounting portion. Valve structure for energy storage devices.

2. The liquid includes liquid paraffin. Valve structure for energy storage device according to claim 1.

3. The viscosity of the aforementioned liquid is in the range of 0.1 mPa·s to 2000 mPa·s. Valve structure for energy storage device according to claim 1 or 2.

4. The aforementioned passage includes an exit facing the external space, It has a sealing member that is attached to close the aforementioned outlet. A valve structure for an energy storage device according to any one of claims 1 to 3.

5. The check valve has a cover material positioned on at least one of the primary and secondary sides, configured to allow the gas to pass through. A valve structure for an energy storage device according to any one of claims 1 to 4.

6. A valve structure for an energy storage device according to any one of claims 1 to 5, The container to which the valve structure for the energy storage device is attached comprises Energy storage device.

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