JP2022102890A - Valve structure for power storage device and power storage device - Google Patents

Abstract

To provide a valve structure for a power storage device and a power storage device that prevent moisture from entering a container in which a power storage device element is housed.SOLUTION: A valve structure for a power storage device includes a passage that communicates the inside and outside of a container that houses a power storage device element, and a check valve that is arranged so as to block the passage, and is opened when the internal pressure of the container rises due to gas generated inside the container, and passes the gas from the inside to the outside of the container, and the check valve includes a valve seat and a valve body that contacts the valve seat in the closed state, and the valve seat and the valve body come into contact with each other at a plurality of places in the closed state.SELECTED DRAWING: Figure 7

Description

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

Patent Document 1 discloses a battery in which a battery element is housed in a pouch. A valve structure having a check valve is attached to the heat seal portion formed along the peripheral edge of the pouch. This check valve is configured to operate when the internal pressure of the pouch rises above a certain level to vent gas.

Patent Document 2 discloses a battery in which a battery element is housed in a box-shaped laminated container. In this laminated container, a flange-shaped heat-sealed portion formed along the peripheral edge thereof is formed with a portion (hereinafter referred to as an easy peel portion) that is easier to peel off than other portions. The easy peel portion is peeled off when the internal pressure of the laminated container rises above a certain level, and degassing is performed through a hole formed in the center of the easy peel portion. The easy peel portion is a destructive valve that does not return to its original state once peeled off, unlike a check valve as in Patent Document 1.

Japanese Unexamined Patent Publication No. 2016-31934 Japanese Unexamined Patent Publication No. 2010-153841

By the way, the check valve is generally a one-way valve and is intended to prevent backflow. However, in a battery as in Patent Document 1, if even a small amount of water contained in the atmosphere is mixed in the pouch, the battery deteriorates, so that it is necessary to prevent backflow with higher accuracy. Therefore, it is practically difficult for a check valve for venting gas in a pouch as in Patent Document 1 to completely prevent the ingress of air into the pouch at a high level required for a battery. .. Therefore, in a battery as in Patent Document 1, there is a problem that moisture contained in the atmosphere is mixed in the pouch and the battery is deteriorated.

On the other hand, in a battery as in Patent Document 2, once the destruction valve is destroyed, the atmosphere enters the laminated container through the passage formed by the destruction. Therefore, even when the break valve is used as in Patent Document 2, there is a problem that the moisture contained in the atmosphere is mixed in the laminated container and the battery is deteriorated.

An object of the present invention is to provide a valve structure capable of suppressing the intrusion of water into a container in which a power storage device element is housed, and a power storage device including the valve structure.

The valve structure for a power storage device according to the first aspect of the present invention is arranged so as to block a passage for communicating the inside and outside of the container accommodating the power storage device element and the passage, and to the gas generated inside the container. A check valve that opens when the internal pressure of the container rises and allows the gas to pass from the inside side to the outside side of the container is provided, and the check valve has a valve seat and a closing valve. The valve body that comes into contact with the valve seat in the state is included, and the valve seat and the valve body come into contact with each other at a plurality of places in the closed state.

The valve structure for a power storage device according to a second aspect of the present invention is a valve structure for a power storage device according to the first aspect, and at least one of the valve seat and the valve body is a multi-stage structure having a plurality of steps. The valve seat and the valve body are in contact with each other via the multi-stage structure in the closed state.

The energy storage device valve structure according to the third aspect of the present invention is the electricity storage device valve structure according to the first aspect or the second aspect, and the valve seat is inserted into the valve seat in the closed state. The valve body includes an insertion portion to be inserted into the insertion hole in the closed state, the insertion hole having a tapered shape toward the inside of the container, and the insertion portion having the insertion portion. , The shape is tapered toward the inside of the container so as to follow the shape of the insertion hole.

The valve structure for a power storage device according to a fourth aspect of the present invention is a valve structure for a power storage device according to any one of the first to third viewpoints, and has a valve body for accommodating the check valve. Further provided, the valve body includes a side wall that guides the movement of the valve body when the check valve transitions from one of the closed and open states to the other.

The valve structure for a power storage device according to a fifth aspect of the present invention is a valve structure for a power storage device according to a fourth aspect, and the side wall discharges the gas when the check valve is in the open state. Includes drain holes formed to allow.

The valve structure for a power storage device according to the sixth aspect of the present invention is a valve structure for a power storage device according to any one of the first to fifth viewpoints, and is in contact with the valve seat and the valve body. It comprises a liquid arranged in such a manner.

The valve structure for a power storage device according to the seventh aspect of the present invention is the valve structure for a power storage device according to the sixth aspect, and the melting point of the liquid is 10 ° C. or lower.

The valve structure for a power storage device according to the eighth aspect of the present invention is the valve structure for a power storage device according to the sixth or seventh aspect, and the boiling point of the liquid is 150 ° C. or higher.

The valve structure for a power storage device according to the ninth aspect of the present invention is a valve structure for a power storage device according to any one of the sixth aspect to the eighth aspect, and the liquid contains liquid paraffin.

The valve structure for a power storage device according to the tenth aspect of the present invention is a valve structure for a power storage device according to any one of the sixth aspect to the ninth aspect, and the viscosity of the liquid is 0.1 mPa. It is included in the range of s to 2000 mPa · s.

The power storage device according to the eleventh aspect of the present invention includes a valve structure for a power storage device according to any one of the first to tenth viewpoints and the container to which the valve structure for the power storage device is attached. Be prepared.

According to the valve structure for a power storage device and the power storage device according to the present invention, it is possible to suppress the intrusion of water into the container in which the power storage device element is housed.

The plan view of the power storage device provided with the valve structure for the power storage device of the first embodiment. FIG. 2 is a cross-sectional view taken along the line D2-D2 of FIG. The front view of the valve structure of FIG. The bottom view of the valve structure of FIG. The plan view of the valve structure of FIG. The perspective view seen from the rear side of the valve structure of FIG. FIG. 4 is a cross-sectional view taken along the line D7-D7 of FIG. The perspective view seen from the bottom surface side of the valve body of FIG. The front view of the valve body of FIG. FIG. 2 is a sectional view of a valve structure for a power storage device according to a second embodiment. The perspective view seen from the upper surface side of the valve seat of FIG. FIG. 3 is a cross-sectional view of a valve seat and a valve body included in the valve structure for a power storage device of a modified example. FIG. 3 is a cross-sectional view of a valve seat and a valve body provided in a valve structure for a power storage device of another modification. Top view of the power storage device of the modified example. Top view of the power storage device of another modification. A plan view of a power storage device of yet another modification. A plan view of a power storage device of yet another modification. Sectional drawing of the valve structure of a modification.

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

[1. First Embodiment]
<1-1. Overall configuration of power storage device>
FIG. 1 shows a plan view of a power storage device 100 including a power storage device valve structure 10 according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line D2-D2 of FIG. In these figures, the parts that are originally invisible from the outside are partially shown by dotted lines for reference. Hereinafter, for convenience of explanation, unless otherwise specified, the vertical direction in FIG. 1 is referred to as "front and back", the left and right direction is referred to as "left and right", and the vertical direction in FIG. 2 is referred to as "up and down". However, the orientation of the power storage device 100 when used is not limited to this.

The power storage device 100 includes an accommodating body 110, a power storage device element 120, a tab 130, and a tab film 140. The housing 110 includes an internal space S1 and a peripheral seal portion 150. The power storage device element 120 is housed in the internal space S1 of the housing body 110. One end of the tab 130 is joined to the power storage device element 120, the other end protrudes outward from the peripheral seal portion 150 of the housing 110, and a part between the one end and the other end is a tab film. It is fused to the peripheral seal portion 150 via 140.

The housing 110 includes a container 110A. The container 110A includes packaging materials 111 and 112. In the outer peripheral portion of the container 110A in a plan view, the packaging materials 111 and 112 are heat-sealed and fused to each other, whereby the peripheral edge sealing portion 150 is formed. Then, the peripheral space S1 of the container 110A blocked from the external space is formed by the peripheral seal portion 150. The peripheral edge sealing portion 150 defines the peripheral edge of the internal space S1 of the container 110A. It should be noted that the mode of heat sealing referred to here is assumed to be a mode of heat fusion from a heat source, ultrasonic fusion, and the like. In any case, the peripheral sealing portion 150 means a portion where the packaging materials 111 and 112 are fused and integrated. As shown in FIG. 2, the packaging material 112, the tab 130, the pair of tab films 140, and the packaging material 111 are integrated in the portion of the peripheral seal portion 150 that sandwiches the tab 130 and the tab film 140. The packaging material 112, the pair of tab films 140, and the packaging material 111 are integrated in the portion of the peripheral seal portion 150 that sandwiches only the pair of tab films 140.

The packaging materials 111 and 112 are made of, for example, a resin molded product or a film. The resin molded product referred to here can be manufactured by a method such as injection molding, pressure molding, vacuum forming, blow molding, or the like, and may be in-molded in order to impart designability and functionality. The type of resin may be polyolefin, polyester, nylon, ABS or the like. Further, the film referred to here is, for example, a resin film that can be manufactured by a method such as an inflation method or a T-die method, or a film obtained by laminating such a resin film on a metal foil. Further, the film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. Further, the multilayer film referred to here may be produced by a coating method, a plurality of films bonded by an adhesive or the like, or may be produced by a multilayer extrusion method.

As described above, the packaging materials 111 and 112 can be variously configured, but in the present embodiment, they are composed of a laminated film. The laminated film can be a laminated body in which a base material layer, a barrier layer, and a heat-sealing resin layer are laminated. The base material layer functions as a base material for the packaging materials 111 and 112, and is typically a resin layer that forms the outer layer side of the container 110A and has an insulating property. The barrier layer has a function of improving the strength of the packaging materials 111 and 112 and preventing at least moisture from entering the power storage device 100, and is typically a metal layer made of an aluminum alloy foil or the like. .. The heat-bondable resin layer is typically made of a heat-bondable resin such as polyolefin, and forms the innermost layer of the container 110A.

The shape of the container 110A is not particularly limited, and may be, for example, a bag shape (pouch shape). The bag shape referred to here may be a three-way seal type, a four-way seal type, a pillow type, a gusset type, or the like. However, the container 110A of the present embodiment has the shape as shown in FIG. 2, and is the packaging material 111 molded in a tray shape and the packaging material 112 which is also molded in a tray shape and superposed on the packaging material 111. Is manufactured by heat-sealing along the outer peripheral portion in a plan view. The packaging material 111 includes an annular flange portion 111A corresponding to an outer peripheral portion in a plan view, and a molding portion 111B continuous with the inner edge of the flange portion 111A and bulging downward from the flange portion 111A. Similarly, the packaging material 112 includes an annular flange portion 112A corresponding to an outer peripheral portion in a plan view, and a molding portion 112B continuous with the inner edge of the flange portion 112A and bulging upward from the flange portion 112A. The packaging materials 111 and 112 are superposed so that the molded portions 111B and 112B bulge in opposite directions. In this state, the flange portion 111A of the packaging material 111 and the flange portion 112A of the packaging material 112 are heat-sealed so as to be integrated to form the peripheral seal portion 150. The peripheral edge sealing portion 150 extends over the entire outer peripheral circumference of the container 110A and is formed in an annular shape. One of the packaging materials 111 and 112 may be in the form of a sheet.

The power storage device element 120 includes at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a power storage member such as a lithium ion battery (secondary battery) or a capacitor. When an abnormality occurs in the power storage device element 120, gas may be generated in the internal space S1 of the container 110A. When the power storage device 100 is a lithium ion battery, the organic solvent which is an electrolyte volatilizes, and the electrolytic solution decomposes, so that the volatile organic solvent, carbon monoxide, carbon dioxide, and methane enter the internal space S1 of the container 110A. , Etan, hydrogen, hydrogen fluoride and other gases can be generated. When the power storage device 100 is a capacitor, gas may be generated in the internal space S1 of the container 110A due to a chemical reaction in the capacitor. Further, the power storage device 100 may be an all-solid-state battery, and in this case, the power 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.

The tab 130 is a metal terminal used for input / output of electric power of the power storage device element 120. The tabs 130 are arranged separately at the left and right end portions of the peripheral seal portion 150 of the container 110A, one of which constitutes a terminal on the positive electrode side and the other constitutes a terminal on the negative electrode side. One end of each tab 130 in the left-right direction is electrically connected to the electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end is the peripheral seal portion 150. It protrudes outward from. The above-mentioned form of the power storage device 100 is particularly preferable for use in an electric vehicle such as an electric vehicle or a hybrid vehicle in which a large number of power storage devices 100 are connected in series and used at a high voltage. The mounting positions of the two tabs 130 constituting the terminals of the positive electrode and the negative electrode are not particularly limited, and may be arranged on the same side of the peripheral seal portion 150, for example.

The metal material constituting the tab 130 is, for example, aluminum, nickel, copper or the like. When the power storage device element 120 is a lithium ion battery, the tab 130 connected to the positive electrode is typically made of aluminum or the like, and the tab 130 connected to the negative electrode is typically copper, nickel or the like. Consists of.

The tab 130 on the left side is sandwiched between the packaging materials 111 and 112 via the tab film 140 at the left end portion of the peripheral sealing portion 150. The tab 130 on the right side is also sandwiched between the packaging materials 111 and 112 via the tab film 140 at the right end portion of the peripheral sealing portion 150.

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, even if the tab 130 and the innermost layers (heat-fusing resin layers) of the packaging materials 111 and 112 are different materials, both can be fixed. The tab film 140 is integrated by being fused and fixed to the tab 130 in advance, and the tab 130 to which the tab film 140 is fixed is sandwiched between the packaging materials 111 and 112 and fused. As shown in 2, they are integrated.

When gas is generated in the internal space S1 of the container 110A with the operation of the power storage device 100, the pressure in the internal space S1 gradually increases. If the pressure in the internal space S1 rises excessively, the container 110A may explode and the power storage device 100 may be damaged. The accommodating body 110 includes a valve structure 10 as a mechanism for preventing such a situation. The valve structure 10 is a degassing valve for adjusting the pressure in the internal space S1, and is attached to, for example, the peripheral seal portion 150 of the container 110A. Hereinafter, the configuration of the valve structure 10 will be described in detail.

<1-2. Structure of valve structure>
FIG. 3 is a front view of the valve structure 10. The valve structure 10 includes a valve body 20. The valve body 20 includes a first body 30, a second body 40, and a check valve 50 (see FIG. 7). In the present embodiment, the first body 30 and the second body 40 are continuously arranged in the order from the inside to the outside (direction from the back side to the front side) of the container 110A (see FIG. 1). FIG. 4 is a view of the valve structure 10 as viewed from the first body 30 side (from the rear side). FIG. 5 is a view of the valve structure 10 as viewed from the second body 40 side (from the front side). FIG. 6 is a perspective view of the valve structure 10 as viewed from the first body 30 side (from the rear side).

FIG. 7 is a cross-sectional view taken along the line D7-D7 of FIG. As shown in FIG. 7, the check valve 50 is accommodated in the accommodation 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 rises due to the gas generated inside the container 110A (see FIG. 1), and allows the gas to pass from the inside side to the outside side of the container 110A. More specifically, the check valve 50 constitutes a relief valve that switches between the open state and the closed state according to the pressure on the primary side thereof, that is, the pressure in the internal space S1 (see FIG. 1). A passage LA is formed inside the valve body 20. The passage LA is a passage that communicates the inside and outside of the container 110A, and has an inlet 20A facing the inner space S1 of the container 110A and an outlet 20B facing the outer space.

The check valve 50 is arranged so as to close the passage LA in the closed state. The check valve 50 is opened when the pressure in the internal space S1 rises due to the gas generated in the internal space S1, and the gas is transferred from its primary side to its secondary side, that is, from the internal space S1. Let it pass to the external space. The check valve 50 seals the internal space S1 from the external space in the closed state.

The first body 30 includes a mounting portion 31 and a connecting portion 32. The mounting portion 31 is a portion for mounting the valve structure 10 to the container 110A. The mounting portion 31 is heat-sealed together with the packaging materials 111 and 112 via the heat-sealing film 11 (see FIG. 1) when the container 110A is molded. By this heat seal, the outer peripheral surface of the mounting portion 31 and the packaging materials 111 and 112 are fused and joined via the heat fusion film 11, and the mounting portion 31 is sandwiched between the packaging materials 111 and 112. In the embodiment, it is fixed to the peripheral seal portion 150 (see FIG. 2).

The connecting portion 32 is arranged outside the peripheral sealing portion 150 and is not sandwiched between the packaging materials 111 and 112 (see FIGS. 1 and 2). Further, the second body 40 arranged further outside the connecting portion 32 is also arranged outside the peripheral edge sealing portion 150, and is not sandwiched between the packaging materials 111 and 112. As a result, the heat generated when the mounting portion 31 is mounted on the container 110A by the heat seal reduces the possibility that the check valve 50 held by the second body 40 will be destroyed due to deformation or the like.

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 have a common central axis C1. The mounting portion 31 has a first vent LX, the second body 40 has a second vent LY, and the connecting portion 32 has a third vent LZ. These ventilation passages LX to LZ also extend coaxially with each other with the central axis C1 as the central axis. In the present embodiment, the inlet 20A and the outlet 20B are arranged not on the outer peripheral surface of the valve body 20 but on the end surface in the front-rear direction, and in particular, the central axis C1 extending linearly in the front-rear direction is the inlet 20A and the outlet 20B. Pass through the center of. Although not limited to this, the cross section orthogonal to the central axis C1 of the ventilation passages LX to LZ is circular. The ventilation passages LX to LZ communicate with each other and form a passage LA as a whole. The third ventilation passage LZ is arranged on the outer side of the container 110A with respect to the first ventilation passage LX. The second ventilation passage LY is arranged further on the outer side of the container 110A than the third ventilation passage LZ.

As shown in FIGS. 4 and 6, the outer shape of the mounting portion 31 is non-circular when visually recognized along the extending direction of the central axis C1. More specifically, when the mounting portion 31 is visually recognized along the extending direction of the central axis C1, the first wing-shaped portion 31A formed thinner toward the left from the central portion in the left-right direction, and to the right. It has a second wing-shaped portion 31B that is formed thinner toward it. Therefore, in the present embodiment, the mounting portion 31 becomes thicker as it approaches the central portion in the width direction (left-right direction) of the power storage device 100, and becomes thinner as it approaches the end portion in the width direction (left-right direction) of the power storage device 100. ..

In the present embodiment, since the first wing-shaped portion 31A and the second wing-shaped portion 31B are formed, the outer peripheral surface of the mounting portion 31 is the upper side covered with the packaging material 112 even in the lower half covered with the packaging material 111. Even in half, each draws a smooth curved surface. Further, for example, as compared with the case where the mounting portion 31 is formed in a cylindrical shape, from the portion of the peripheral edge sealing portion 150 in which the mounting portion 31 is not sandwiched by the first wing-shaped portion 31A and the second wing-shaped portion 31B. At the position of the peripheral seal portion 150 where the attachment portion 31 is sandwiched, the change in the thickness of the power storage device 100 in the vertical direction becomes smooth. As a result, no unreasonable force is applied to the packaging materials 111 and 112 in the peripheral portion of the peripheral seal portion 150 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 fusion film 11.

The outer shape of the connecting portion 32 has a shape in which a part of a cylinder with the central axis C1 as the central axis is cut out. More specifically, the outer shape of the connecting portion 32 is such that a cylinder centered on the central axis C1 is cut out in a plane separated from the central axis C1 by a certain distance, and the plane is formed with respect to the central axis C1. It has a shape like a notch in a plane at a symmetrical position. Therefore, the connecting portion 32 has a pair of planes, the first plane 32A and the second plane 32B. The first plane 32A and the second plane 32B are parallel to each other (including the case where they are substantially parallel; the same applies hereinafter). The first plane 32A and the second plane 32B are parallel to the extending direction of the central axis C1 (including a case where they are substantially parallel; the same applies hereinafter). Further, in the present embodiment, the first plane 32A and the second plane 32B are parallel to each other in the direction in which the peripheral edge sealing portion 150 extends (including a case where they are substantially parallel; the same applies hereinafter). The outer peripheral 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. The curved surfaces 32C and 32D each have an arc shape centered on the central axis C1 when viewed along the extending direction of 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 peripheral surface of the cylindrical member so that the first plane 32A and the second plane 32B are formed.

The second body 40 has a cylindrical shape, and together with the first body 30, defines a storage space S2 for accommodating the check valve 50. The first body 30 and the second body 40 are assembled in a state where the check valve 50 is accommodated in the accommodation space S2.

The bonding mode between the first body 30 and the second body 40 is, for example, at least one of bonding by an adhesive, bonding by a screw structure, and bonding by meshing of irregularities. In the present embodiment, the male screw 32X (see FIG. 7) formed on the outer surface of the connecting portion 32 of the first body 30 and the female screw 40A (see FIG. 7) formed on the inner surface of the second body 40 are engaged with each other, and The first body 30 and the second body 40 are bonded by the adhesive applied to the male screw 32X and the female screw 40A. The material of the adhesive is not particularly limited, but may be composed of an acid-modified polyolefin and an epoxy resin. Such an adhesive is superior in that it can suppress deterioration of the adhesive performance due to the electrolytic solution contained in the container 110A, as compared with the case where an adhesive made of a modified silicone resin is used, for example. Any means can be adopted for the connection between the first body 30 and the second body 40. Therefore, in the present embodiment, at least one of the structure related to the meshing of the male screw 32X and the female screw 40A and the adhesive may be omitted.

As described above, in the present embodiment, the outer shapes of the mounting portion 31, the connecting portion 32, and the second body 40 are assigned to the respective portions when viewed along the extending direction of the central axis C1. Each has a different shape depending on the above.

The second body 40 holds a portion having a main structure for demonstrating the function of the valve structure 10 as a degassing valve. In this embodiment, the check valve 50 has a spring 60, a valve seat 70, and a valve body 80 as a valve mechanism housed in a second air passage LY inside the second body 40. The spring 60, the valve body 80, and the valve seat 70 are arranged in this order from the outlet 20B to the inlet 20A in the second air passage LY. In the present embodiment, as shown in FIGS. 7 and 8, the first body 30 and the valve seat 70 are configured as separate parts, but these may be integrally configured.

The valve seat 70 receives the valve body 80 urged from the outside by the spring 60, and at this time, the closed state of the valve structure 10 is formed. The spring 60 is, for example, a coil spring, but is not limited to this, and may be, for example, a leaf spring.

In the present embodiment, the valve seat 70 has a shape similar to a cylinder extending with the central axis C1 as the central axis. The valve seat 70 has an insertion hole 71 into which a part of the valve body 80 is inserted in the closed state of the check valve 50. In the present embodiment, the inner surface 71A of the insertion hole 71 is generally a smooth surface. The diameter of the insertion hole 71 decreases toward the inlet 20A. That is, the insertion hole 71 has a tapered shape toward the inlet 20A.

The valve body 80 has a columnar base 81, a conical insertion portion 82 extending from the lower surface 81A of the base 81 toward the valve seat 70, and a columnar shaft portion extending from the upper surface 81B of the base 81 toward the outlet 20B. Has 83. The base portion 81, the insertion portion 82, and the shaft portion 83 extend with the central axis C1 as the central axis. In the closed state of the check valve 50, the insertion portion 82 is inserted into the insertion hole 71 of the valve seat 70. The outer shape of the insertion portion 82 is configured to follow the inner shape of the insertion hole 71. Specifically, the diameter of the insertion portion 82 decreases from the base 81 toward the valve seat 70. That is, the insertion portion 82 has a tapered shape from the base portion 81 toward the valve seat 70. Therefore, when the check valve 50 shifts from the open state to the closed state, the valve body 80 is guided to a predetermined position by the insertion hole 71. Therefore, the position of the valve body 80 with respect to the valve seat 70 when the check valve 50 is closed is unlikely to shift. In other words, the position of the valve body 80 with respect to the central axis C1 is unlikely to shift. The spring 60 extends spirally with the central axis C1 as the central axis. The shaft portion 83 of the valve body 80 is inserted into the space inside the spring 60. Therefore, the valve body 80 and the spring 60 are connected.

In the present embodiment, the valve seat 70 and the valve body 80 are configured to come into contact with each other at a plurality of places so that the valve seat 70 and the valve body 80 come into contact with each other more firmly when the check valve 50 is closed. .. More specifically, in the present embodiment, at least one of the valve seat 70 and the valve body 80 includes a multi-stage structure 90 having a plurality of steps, and the valve seat 70 and the valve body 80 are in a closed state of the check valve 50. In contact with each other via the multi-stage structure 90. In this embodiment, the multi-stage structure 90 is formed on the valve body 80.

As shown in FIGS. 8 and 9, the insertion portion 82 of the valve body 80 is formed with a multi-stage structure 90 including a plurality of convex portions 91 and a plurality of concave portions 92. Such a multi-stage structure 90 can be realized, for example, by forming a recess 92 in the insertion portion 82. The convex portion 91 and the concave portion 92 are arranged alternately in the extending direction of the central axis C1. The convex portion 91 and the concave portion 92 are formed as a whole in the circumferential direction of the insertion portion 82. The number of convex portions 91 in the multi-stage structure 90 can be arbitrarily selected as long as it is 2 or more. In this embodiment, the multi-stage structure 90 has six protrusions 91. The number of recesses 92 in the multi-stage structure 90 is determined, for example, based on the number of protrusions 91. In this embodiment, the multi-stage structure 90 has six recesses 92.

In the closed state of the check valve 50, the insertion portion 82 is inserted into the insertion hole 71, and the convex portion 91 of the multi-stage structure 90 formed in the insertion portion 82 comes into contact with the inner surface 71A of the insertion hole 71. In the present embodiment, since the multi-stage structure 90 has six convex portions 91, the valve seat 70 and the valve body 80 come into contact with each other at six points in the closed state of the check valve 50. Therefore, when the urging force of the spring 60 is the same, for example, the valve seat 70 and the valve body 80 of the present embodiment have stronger pressure than the case where the valve seat 70 and the valve body 80 come into surface contact at one place. Contact with. Therefore, when the atmosphere and the moisture contained therein enter the valve structure 10 through the outlet 20B in the closed state of the check valve 50, the moisture or the like enters the valve structure 10 through the outlet 20B, and the moisture or the like enters the container 110A rather than the check valve 50. The check valve 50 prevents the vehicle from entering the inside of the vehicle. Therefore, it is possible to prevent the atmosphere and the moisture contained therein from entering the container 110A.

The side wall 42 of the second body 40 extends along the central axis C1 so that the movement of the valve body 80 can be guided when the check valve 50 transitions from one of the closed and open states to the other. Substantially no gap is formed between the inner surface 42A of the side wall 42 and the surface of the base 81 of the valve body 80. In other words, the inner surface 42A of the side wall 42 and the surface of the base 81 of the valve body 80 are in contact with each other. Therefore, when the check valve 50 shifts from one of the closed state and the open state to the other, the base portion 81 of the valve body 80 moves along the central axis C1 while being in contact with the inner surface 42A of the side wall 42.

Since the inner surface 42A of the side wall 42 and the surface of the base 81 of the valve body 80 are in contact with each other, when the check valve 50 is opened, there are many passages between the side wall 42 and the valve body 80. Gas is difficult to pass through. Therefore, in the present embodiment, the discharge hole 42B is formed on the side wall 42 in addition to the outlet 20B so that the gas can be smoothly discharged when the check valve 50 is in the open state. The discharge hole 42B is a hole that penetrates the side wall 42. When gas is generated in the internal space S1 and the check valve 50 is opened, most of the gas is discharged to the outside through the gap between the valve seat 70 and the side wall 42 and the discharge hole 42B. A part of the gas is also discharged to the outside through the outlet 20B. The position where the discharge hole 42B is formed on the side wall 42 can be arbitrarily selected. In the present embodiment, the discharge hole 42B is formed on the side wall 42 at a position facing the valve seat 70. The discharge hole 42B may be formed on the side wall 42 at a position facing the valve body 80.

The valve seat 70 and the first body 30 can be adhered to each other by, for example, an adhesive. The material of the adhesive is not particularly limited, but preferred examples of the case where the valve seat 70 is made of fluororubber and the first body 30 is made of a metal such as aluminum are the first body 30 and the second body 40. It is the same as the adhesive exemplified for bonding. Further, from the viewpoint of preventing the opening of the valve structure 10, the adhesive can be appropriately applied to various other places. For example, an adhesive can be applied between the rear end surface 41 of the second body 40 and the front end surface 32E of the connecting portion 32.

The mounting portion 31 is fixed to the peripheral seal portion 150 so that the 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 communicates with the internal space S1 of the container 110A. Therefore, when the pressure in the internal space S1, that is, the pressure in the space on the primary side of the check valve 50 reaches a predetermined pressure, the gas flows out from the internal space S1 and passes through the first ventilation passage LX and the third ventilation passage LZ. Presses the valve body 80 toward the outlet 20B. When the valve body 80 is pressed and the valve body 80 separates from the valve seat 70, the spring 60 is deformed, the valve body 80 moves toward the outlet 20B, and the check valve 50 is formed in an open state. In this open state, the gas generated in the internal space S1 flows out toward the outlet 20B and the discharge hole 42B through the gap formed between the valve body 80 and the valve seat 70, and is discharged to the external space. .. In this way, when the gas in the internal space S1 is discharged through the passage LA, the pressure on the internal space S1 side that presses the valve body 80 toward the outlet 20B weakens, and the spring 60 causes the valve body 80 to press the valve body 80. The force that urges the entrance 20A side increases. As a result, the shape of the spring 60 is restored, and the closed state of the check valve 50 is formed again.

The check valve 50 can prevent the atmosphere from entering the internal space S1 of the container 110A from the external space in the closed state. After the check valve 50 is opened once, the internal space S1 is maintained in a relatively high pressure state equal to or higher than the atmospheric pressure, so that the entry of the atmosphere into the internal space S1 is particularly unlikely to occur. The check valve 50 as described above can effectively prevent the entry of the atmosphere into the internal space S1 and prevent deterioration of the power storage device element 120 due to moisture or the like contained therein. .. Further, even when the check valve 50 is open, it is unlikely that the atmosphere will enter the internal space S1. This is because, in the open state, the pressure on the primary side of the check valve 50 is higher than or equivalent to the pressure on the secondary side.

The material constituting each part of the valve structure 10 is not particularly limited. As a preferred example, the valve body 80 can be made of a fluororesin such as polytetrafluoroethylene (PTFE), and the valve seat 70 can be made of a fluororubber such as vinylidene fluoride (FKM). Further, the spring 60 can be made of a metal such as stainless steel, and the mounting portion 31, the second body 40 and the connecting portion 32 can be made of a metal such as an aluminum alloy, stainless steel, a steel plate, or titanium. Further, the valve body 80 may be made of a metal such as aluminum or stainless steel, or a fluororubber such as PTFE or FKM. When the valve body 80 is made of fluororubber such as FKM, the valve seat 70 is preferably made of fluororesin such as PTFE.

The heat-sealing film 11 shown in FIG. 1 and the like is configured to be adhered to both the valve structure 10 and the packaging materials 111 and 112 of the container 110A by heat sealing. The heat-sealing film 11 is accommodated in the accommodation space S2 (see FIG. 7) with the check valve 50, and the attachment portion 31 of the first body 30 is before the first body 30 and the second body 40 are assembled. Is fused to. The heat-sealing film 11 is fused to the mounting portion 31 so as to cover most of the surface of the mounting portion 31. As the heat-sealing film 11, various known adhesive films can be adopted. The heat-sealed film 11 may be, for example, a single-layer film of maleic anhydride-modified polypropylene (PPa), or may be a multi-layer laminated film of PPa, polyethylene naphthalate (PEN), and PPa. good. Further, a laminated film having a plurality of layers of PPa, polypropylene (PP), and PPa may be applied. Further, instead of the above-mentioned PPa resin, a metal-bondable resin such as an ionomer resin, modified polyethylene, and EVA can also be applied. In the present embodiment, the heat-sealing film 11 adopts a laminated film having a three-layer structure including a core material, which is made of PPa / polyester fiber / PPa. As the core material, various known materials other than the polyester fiber described above can be adopted. For example, the core material may be a polyester film such as PEN, polyethylene terephthalate, or polybutylene terephthalate, a polyamide fiber, or a carbon fiber.

Further, it is preferable that the surface of the mounting portion 31 is coated with a corrosion inhibitor to form a corrosion preventive coating layer, particularly from the viewpoint of electrolytic solution resistance. This is especially true when the mounting portion 31 is made of a metal such as aluminum, but it can also be applied 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 of a corrosion inhibitor and then performing a baking treatment. As a result, a corrosion prevention coating layer can be formed on the outer surface of the mounting portion 31 and the inner surface facing the first air passage LX, and the outer surface is corroded by the gas generated from the power storage device element 120, and It is possible to prevent corrosion of the inner surface due to the gas passing through the first ventilation path LX. Further, particularly from the viewpoint of electrolytic solution resistance, the same coating is 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 prevention coating layer. You may. When the surfaces of the connecting portion 32, the second body 40, and the check valve 50 are coated with a corrosion inhibitor, in particular, the male screw 32X of the connecting portion 32, the female screw 40A of the second body 40, the valve body 80, and the second body 40. It is preferable to form a corrosion prevention coating layer in a predetermined range including a portion where the body 40 and the valve seat 70 come into contact with each other. 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 electrolytic solution, it is meaningful to apply such a coating to the mounting portion 31 in particular. The material of the corrosion inhibitor is not particularly limited, but an acid resistant one is preferable, and the corrosion inhibitor film layer can be formed by chromic acid chromate treatment, phosphoric acid chromate treatment or the like.

[2. Second Embodiment]
In the second embodiment, the configuration of the valve structure 10 is different from that in the first embodiment. Other configurations are basically the same as those of the first embodiment. Hereinafter, the same configurations as those of the first embodiment are designated by the same reference numerals, the description thereof will be omitted, and the parts different from those of the first embodiment will be mainly described.

FIG. 10 is a cross-sectional view of the valve structure 200 of the second embodiment. In the present embodiment, the multi-stage structure 290 is formed in the insertion hole 71 of the valve seat 70. The surface of the base 81 of the valve body 80 is generally a smooth surface.

As shown in FIGS. 10 and 11, the insertion hole 71 of the valve seat 70 is formed with a multi-stage structure 290 including a plurality of convex portions 291 and a plurality of concave portions 292. Such a multi-stage structure 290 can be realized, for example, by forming a recess 292 in the insertion hole 71. The convex portion 291 and the concave portion 292 are alternately arranged in the extending direction of the central axis C1. The convex portion 291 and the concave portion 292 are formed as a whole in the circumferential direction of the insertion hole 71. The number of convex portions 291 in the multi-stage structure 290 can be arbitrarily selected as long as it is 2 or more. In this embodiment, the multi-stage structure 290 has six protrusions 291. The number of recesses 292 in the multi-stage structure 290 is determined, for example, based on the number of protrusions 291. In this embodiment, the multi-stage structure 290 has six recesses 292.

In the closed state of the check valve 50, the insertion portion 82 is inserted into the insertion hole 71, and the convex portion 291 of the multi-stage structure 290 formed in the insertion hole 71 comes into contact with the surface of the insertion portion 82. In the present embodiment, since the multi-stage structure 290 has six convex portions 291, the valve seat 70 and the valve body 80 come into contact with each other at six points in the closed state of the check valve 50. Therefore, when the urging force of the spring 60 is the same, for example, the valve seat 70 and the valve body 80 of the present embodiment have stronger pressure than the case where the valve seat 70 and the valve body 80 come into surface contact at one place. Contact with. Therefore, when the atmosphere and the moisture contained therein enter the valve structure 10 through the outlet 20B in the closed state of the check valve 50, the moisture or the like enters the valve structure 10 through the outlet 20B, and the moisture or the like enters the container 110A rather than the check valve 50. The check valve 50 prevents the vehicle from entering the inside of the vehicle. Therefore, it is possible to prevent the atmosphere and the moisture contained therein from entering the container 110A.

<3. Modification example>
Each of the above embodiments is an example of a valve structure for a power storage device according to the present invention and a form that the power storage device can take, and is not intended to limit the form. The valve structure for a power storage device and the power storage device according to the present invention may take a form different from the embodiment exemplified in each embodiment. One example thereof is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a new configuration is added to each embodiment. Some examples of modifications of each embodiment are shown below. It should be noted that the following gist of the modified example can be similarly applied to the second embodiment in addition to the first embodiment.

<3-1>
The configurations of the valve seat 70 and the valve body 80 are not limited to those shown in each embodiment, and can be arbitrarily changed.

FIG. 12 is a cross-sectional view showing a valve seat 370 and a valve body 380 of a modified example. The valve seat 370 of this modification has a cylindrical shape. A multi-stage structure 390 is formed on the upper surface 371 of the valve seat 370. The multi-stage structure 390 has a plurality of convex portions 391 and a plurality of concave portions 392. The valve body 380 has a columnar base portion 381 and a columnar shaft portion 382 extending from the upper surface 381A of the base portion 381 toward the side opposite to the valve seat 370. The lower surface 381B of the base portion 381 is generally a smooth surface. In the closed state of the check valve 50, the lower surface 381B of the base portion 381 comes into contact with the plurality of convex portions 391. A multi-stage structure may be formed on the lower surface 381B of the base portion 381. In this case, the upper surface 371 of the valve seat 370 may be a smooth surface.

FIG. 13 is a cross-sectional view showing a valve seat 470 and a valve body 480 of another modified example. The valve seat 470 of this modification has a cylindrical shape and has an insertion hole 471 into which a part of the valve body 480 is inserted in the closed state of the check valve 50. A multi-stage structure 490 is formed on the side surface 471A of the insertion hole 471. The multi-stage structure 490 has a plurality of convex portions 491 and a plurality of concave portions 492. The valve body 480 has a columnar base portion 481 and a columnar shaft portion 482 extending from the upper surface 481A of the base portion 481 toward the side opposite to the valve seat 470. Of the surface of the base 481, at least the side surface 481C is a smooth surface. In this embodiment, the entire surface of the base 481 is a smooth surface. In the closed state of the check valve 50, the lower surface 481B of the base 481 is in contact with the bottom surface 471B of the insertion hole 471, and the side surface 481C is in contact with the plurality of convex portions 491. A multi-stage structure may be formed on the side surface 481C of the base portion 481. In this case, the side surface 471A of the insertion hole 471 is a smooth surface.

<3-2>
The configuration of the multi-stage structure 90 and 290 is not limited to that shown in each embodiment, and can be arbitrarily changed. For example, in the first embodiment, in addition to the multi-stage structure 90 formed on the valve body 80, the multi-stage structure 290 formed on the valve seat 70 shown in the second embodiment can also be added. In this modification, when the check valve 50 is in the closed state, the convex portion 91 of the multi-stage structure 90 formed in the valve body 80 fits into the concave portion 292 of the multi-stage structure 290 formed in the valve seat 70. Similarly, the convex portion 291 of the multi-stage structure 290 formed on the valve seat 70 fits into the concave portion 92 of the multi-stage structure 90 formed on the valve body 80.

<3-3>
The valve seat 70 and the valve body 80 may be in contact with each other at a plurality of locations in the closed state of the check valve 50. Therefore, for example, in the first embodiment, a plurality of protrusions protruding from the surface of the insertion portion 82 may be provided instead of the multi-stage structure 90. Similarly, in the second embodiment, instead of the multi-stage structure 290, a plurality of protrusions protruding from the inner surface 71A of the insertion hole 71 may be provided.

<3-4>
The configuration of the peripheral seal portion 150 is not limited to that shown in each embodiment, and can be arbitrarily changed. As shown in FIG. 14, the peripheral seal portion 150 may have inclined seal portions 151 and 152 whose seal width becomes narrower as they approach the valve structure 10. As shown in FIG. 15, the peripheral seal portion 150 has inclined seal portions 251 and 252 inclined so as to approach the valve seal portion 253 to which the valve structure 10 and the packaging materials 111 and 112 are sealed. May be. As shown in FIG. 16, the peripheral seal portion 150 has stepped inclined seal portions 351 and 352 that are inclined so as to approach the valve seal portion 353 to which the valve structure 10 and the packaging materials 111 and 112 are sealed. May have. As shown in FIG. 17, the peripheral seal portion 150 may have inclined seal portions 451 and 452 that are inclined so as to approach the valve structure 10 and have a substantially constant seal width. According to the modification shown in FIGS. 14 to 17, since the gas generated in the internal space S1 is guided toward the valve structure 10, the gas can be suitably discharged through the valve structure 10.

<3-5>
As shown in FIG. 18, the valve structure 10 is a liquid arranged so as to be in contact with the valve body 80 and the valve seat 70 in order to prevent moisture from entering the internal space S1 (see FIG. 1). It may be provided with 500. The range surrounded by the ellipse shown in FIG. 18 is an example of the range in which the liquid 500 exists. The type of liquid 500 can be arbitrarily selected. In this embodiment, the liquid 500 is liquid paraffin. As the liquid 500, a liquid oil such as silicone oil, an ionic liquid or the like can also be used. In a preferred example, the liquid 500 preferably has the property of being present as a liquid under the normal usage environment of the power storage device 100. From such a viewpoint, the melting point of the liquid 500 is preferably 10 ° C. or lower, and more preferably 0 ° C. or lower. Similarly, the boiling point of the liquid 500 is preferably 150 ° C. or higher.

The viscosity of the liquid 500 can be arbitrarily selected. In a preferred example, the viscosity of the liquid is determined based on the viewpoint of suitable permeation of the gas and the viewpoint of handling. A preferred example of the maximum viscosity of the liquid 500 is 2000 mPa · s. When the viscosity of the liquid 500 is 2000 mPa · s or less, the gas can be suitably permeated. A more preferred example of the maximum viscosity of the liquid 500 is 500 mPa · s. A more preferred example of the maximum viscosity of the liquid 500 is 100 mPa · s. A preferred example of the minimum viscosity of the liquid 500 is 0.1 mPa · s. When the viscosity of the liquid 500 is 0.1 mPa · s or more, it can be handled suitably. A more preferable example of the minimum viscosity of the liquid 500 is 0.5 mPa · s. A more preferable example of the minimum viscosity of the liquid 500 is 1.0 mPa · s. An example of a preferable range of the viscosity of the liquid 500 is 0.1 mPa · s to 2000 mPas. An example of a more preferable range of the viscosity of the liquid 500 is 0.5 mPa · s to 500 mPas. An example of a more preferable range of the viscosity of the liquid 500 is 1.0 mPa · s to 100 mPas. The viscosity of the liquid 500 is a viscosity in the measurement range of 10 ° C to 40 ° C. When the liquid 500 is crude oil or petroleum, the viscosity of the liquid 500 is calculated by multiplying the kinematic viscosity measured based on "JIS K2283 crude oil and petroleum products-kinematic viscosity test method and viscosity index calculation method". The viscosity to be. When the liquid 500 is other than crude oil and petroleum, the viscosity of the liquid 500 is the viscosity measured based on "JIS Z8803 Liquid Viscosity Measuring Method".

The specific arrangement mode 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 the example shown in FIG. 18, in the closed state of the check valve 50, a portion of the surface of the valve seat 80 that contacts the valve seat 70 and a portion of the surface of the valve seat 70 that contacts the valve body 80. Arranged to at least adhere to. In another example, the liquid 500 is filled in a predetermined range of the accommodation space S2.

<3-6>
The container 110A is configured by heat-sealing the packaging material 111 and the packaging material 112, but the container 110A may be configured by folding one packaging material and heat-sealing the peripheral portion.

<3-7>
The container 110A may be composed of the above-mentioned packaging materials 111 and 112, but may also be, for example, a metal can.

10, 200: Valve structure for power storage device 20: Valve body 42: Side wall 42B: Discharge hole 50: Check valve 70, 370, 470: Valve seat 71: Insert hole 80, 380, 480: Valve body 82: Insert 100: Power storage device 110A: Container 120: Power storage device element 90, 290: Multi-stage structure LA: Passage

Claims (11)

A passage that communicates the inside and outside of the container that houses the power storage device element,
It is arranged so as to block the passage, and is opened when the internal pressure of the container rises due to the gas generated inside the container, and the gas is passed from the inside side to the outside side of the container. With a check valve,
The check valve includes a valve seat and a valve body that contacts the valve seat in the closed state.
The valve seat and the valve body are valve structures for a power storage device that come into contact with each other at a plurality of places in the closed state. At least one of the valve seat and the valve body includes a multi-stage structure having a plurality of steps.
The valve structure for a power storage device according to claim 1, wherein the valve seat and the valve body are in contact with each other via the multi-stage structure in the closed state. The valve seat includes an insertion hole into which the valve body is inserted in the closed state.
The valve body includes an insertion portion to be inserted into the insertion hole in the closed state.
The insertion hole has a tapered shape toward the inside of the container.
The valve structure for a power storage device according to claim 1 or 2, wherein the insertion portion has a shape that tapers toward the inside of the container so as to follow the shape of the insertion hole. Further equipped with a valve body for accommodating the check valve,
The valve body according to any one of claims 1 to 3, wherein the valve body includes a side wall that guides the movement of the valve body when the check valve shifts from one of the closed state and the open state to the other. Valve structure for power storage devices. The valve structure for a power storage device according to claim 4, wherein the side wall includes a discharge hole formed so that the gas can be discharged when the check valve is in the open state. The valve structure for a power storage device according to any one of claims 1 to 5, comprising a liquid arranged so as to be in contact with the valve seat and the valve body. The melting point of the liquid is 10 ° C. or lower.
The valve structure for a power storage device according to claim 6. The valve structure for a power storage device according to claim 6 or 7, wherein the liquid has a boiling point of 150 ° C. or higher. The valve structure for a power storage device according to any one of claims 6 to 8, wherein the liquid contains liquid paraffin. The valve structure for a power storage device according to any one of claims 6 to 9, wherein the viscosity of the liquid is in the range of 0.1 mPa · s to 2000 mPa · s. The valve structure for a power storage device according to any one of claims 1 to 10.
A power storage device including the container to which the valve structure for the power storage device is attached.

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