JP2020053177A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of discharging gas to the outside when the gas occurs inside the power storage device while maintaining high sealing performance of the power storage device.SOLUTION: A power storage device includes a power storage device element, a container which is configured by a laminate including at least a base layer, a barrier layer, and a heat-fusible resin layer in this order and accommodates the power storage device element therein, and a valve device communicating with the inside of the container, the heat-fusible resin layers face each other at the peripheral edge of the container, a peripheral edge joint portion where the heat-fusible resin layers facing each other and fused together are formed at the peripheral edge of the container, at least a part of the valve device is interposed between the heat-fusible resin layers facing each other at the peripheral joint portion, whereby the valve device is attached to the container, and the valve device is set so as to be opened while a differential pressure between a primary side and a secondary side of the valve device is within a range from 0.05 MPa or more to 0.3 MPa or less.SELECTED DRAWING: None

Description

  The present disclosure relates to a power storage device.

  2. Description of the Related Art Conventionally, various types of power storage devices have been developed. In all power storage devices, a packaging material (outer packaging material) is an indispensable member for sealing power storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been frequently used as exterior materials for power storage devices.

  On the other hand, in recent years, with increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, power storage devices are required to have various shapes and to be thinner and lighter. However, a metal exterior material for a power storage device, which has been frequently used in the past, has a drawback that it is difficult to keep up with diversification of shapes and there is a limit in weight reduction.

  Therefore, in recent years, as a packaging material for an electricity storage device that can be easily processed into various shapes and can be made thinner and lighter, a film-like material in which a base material / aluminum foil layer / heat-fusible resin layer is sequentially laminated is used. Exterior materials have been proposed.

  In such a film-like exterior material, a concave portion is generally formed by cold molding, and an electricity storage device element such as an electrode or an electrolytic solution is arranged in a space formed by the concave portion. By heat-sealing the layers, an electricity storage device in which the electricity storage device element is accommodated inside the exterior material is obtained.

Patent No. 4892842

  There is a method of providing a gas vent valve for releasing gas, a weak seal portion, a hole, a cut, etc., in case an abnormality occurs in the power storage device and gas is generated inside and the internal pressure rises excessively.

  For example, Patent Literature 1 discloses a lithium secondary battery in which an electrode unit having a positive electrode and a negative electrode and a nonaqueous electrolyte are sealed in a battery container, and the battery container has a flat shape having two opposed wide surfaces. An internal pressure release mechanism that is activated on at least one of the wide surfaces of the battery container when the internal pressure of the container rises, and has an opening area corresponding to at least 3% of the area of the wide surface by the operation. An internal pressure release mechanism designed to form a through hole that communicates the inside and outside of the container is provided, and the internal pressure release mechanism has at least a part of the through hole when the battery is seen through from the thickness direction of the battery container. A device designed to open at a position deviated from the electrode unit in the surface direction is disclosed.

  However, when the internal pressure release mechanism is provided in the container itself that seals the battery element as in Patent Literature 1, there is a concern that the strength of the container made of the film-shaped exterior material is reduced, and the sealing performance becomes insufficient. is there. Further, the film-like exterior material has high flexibility and is easily deformed as compared with a metal can or the like. For this reason, when the internal pressure release mechanism is provided in the exterior material itself as in Patent Literature 1, the pressure at the time of releasing the internal pressure is likely to vary, and a stable internal pressure release property may be lacking.

  As described above, it is difficult to appropriately discharge gas generated inside to the outside while maintaining high hermeticity in the conventional power storage device including the film-shaped exterior material itself provided with the gas release mechanism.

  In addition, for example, a medium-sized or large-sized power storage device such as a vehicle-mounted device or a stationary device has a large electric capacity and a large weight of a battery element. Therefore, particularly high sealing performance and appropriate gas release properties are required.

  An object of the present disclosure is to provide a power storage device that can release a gas to the outside when a gas is generated inside while maintaining a high sealing property of the power storage device.

  The inventors of the present disclosure have made intensive studies in order to solve the above-mentioned problems. As a result, the power storage device element is constituted by a laminate having at least a base layer, a barrier layer, and a heat-fusible resin layer in this order, and a housing body for housing the power storage device element therein; Separate from the body, a power storage device including a valve device that communicates with the inside of the housing, and further, a differential pressure between a primary side and a secondary side of the valve device attached to the housing is within a predetermined value range. In such a case, by setting the valve device to be opened, when gas is generated inside while maintaining the high sealing property of the power storage device, the gas can be appropriately discharged to the outside. Was found.

The present disclosure is an invention completed by further study based on such knowledge. That is, the present disclosure provides the following aspects of the invention.
A power storage device element,
At least, a base body, a barrier layer and a heat-fusible resin layer are configured by a laminate having in this order, a housing body for housing the electricity storage device element therein,
A valve device communicating with the inside of the container,
At the periphery of the container, the heat-fusible resin layer faces,
On the peripheral edge of the container, a peripheral joint portion where the opposed heat-fusible resin layers are fused to each other is formed,
At least a portion of the valve device is sandwiched between the heat-fusible resin layers facing each other at the peripheral joint portion, so that the valve device is attached to the container,
The power storage device, wherein the valve device is set such that the valve device is opened when a differential pressure between a primary side and a secondary side of the valve device is in a range of 0.05 MPa or more and 0.3 MPa or less.

  Advantageous Effects of Invention According to the present disclosure, it is possible to provide an electricity storage device that can appropriately discharge gas to the outside when a gas is generated inside while maintaining high sealing properties of the electricity storage device.

FIG. 3 is a plan view of the power storage device according to the first embodiment. It is II-II sectional drawing of FIG. It is a figure showing a container. It is a figure showing an example of section structure of packaging material. FIG. 2 is a plan view of the valve device according to Embodiment 1. It is VI-VI sectional drawing of FIG. FIG. 7 is a sectional view taken along line VII-VII of FIG. 5. FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. 1, and is a diagram for explaining a mounting state of the valve device. 5 is a flowchart illustrating a procedure for manufacturing the power storage device. It is a figure which shows the operation | movement which mounts a valve apparatus between a flange part and packaging material. FIG. 10 is a plan view of a valve device according to Embodiment 2. It is XII-XII sectional drawing of FIG. FIG. 13 is a plan view of a valve device according to Embodiment 3. It is XIV-XIV sectional drawing of FIG. 13 is a plan view of a valve device according to Embodiment 4. FIG. It is XVI-XVI sectional drawing of FIG. 15 is a plan view of a valve device according to Embodiment 5. FIG. 15 is a plan view of a valve device according to Embodiment 6. FIG. It is XIX-XIX sectional drawing of FIG. 15 is a plan view of a valve device according to Embodiment 7. FIG. FIG. 21 is a sectional view taken along the line XXI-XXI in FIG. 20. It is a figure showing a situation at the time of attachment to a container of a valve device. It is a figure showing a section of a valve device in modification 1. It is a figure showing a section of a valve device in modification 2. It is a figure showing a section of a valve device in modification 3. It is a top view of the valve device in the modification 4. It is XXVII-XXVII sectional drawing of FIG. It is a top view of the packaging material in the modification 5. FIG. 29 is a sectional view taken along the line XXIX-XXIX of FIG. 28. It is a schematic diagram of the valve device used in the Example. It is a schematic diagram which shows the crystal grain in the cross section of the thickness direction of an aluminum foil.

  The power storage device of the present disclosure includes a power storage device element, a housing, and a valve device. The container is constituted by a laminate having at least a base material layer, a barrier layer, and a heat-fusible resin layer in this order. The housing houses the power storage device element therein. The valve device communicates with the inside of the container. In the power storage device of the present disclosure, the heat-fusible resin layer faces the periphery of the housing. Further, a peripheral joint portion in which opposing heat-fusible resin layers are fused to each other is formed at the peripheral edge of the container. The valve device is attached to the container because at least a part of the valve device is sandwiched between the heat-fusible resin layers facing each other at the peripheral joining portion. Further, the valve device is set so that the valve device is opened when the differential pressure between the primary side and the secondary side of the valve device is in the range of 0.05 MPa or more and 0.3 MPa or less.

  With the power storage device of the present disclosure having such features, when gas is generated inside while maintaining the high sealing property of the power storage device, the gas can be appropriately discharged to the outside. it can.

  Hereinafter, the valve device for a power storage device of the present disclosure will be described in detail. In this specification, a numerical range indicated by “to” means “over” and “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less. Further, a specific embodiment of a valve device for a power storage device described later will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts have the same reference characters allotted, and description thereof will not be repeated.

  In the power storage device of the present disclosure, the container is configured by a laminate having the base material layer, the barrier layer, and the heat-fusible resin layer in this order. The differential pressure between the primary side and the secondary side of the valve device attached to the container (that is, the opening pressure of the valve device) is in the range of 0.05 MPa or more and 0.3 MPa or less. When the differential pressure of the valve device attached to the container is within the range, while the gas is generated inside while maintaining the high sealing property of the power storage device, the gas is preferably sent to the outside. Can be released. In addition, since the differential pressure is set within the range, gas of the electrolytic solution or the like generated by the repeated chemical reaction of the power storage device can be stably discharged to the outside, and the internal pressure of the power storage device becomes excessive. The gas can be released before rising. On the other hand, when the differential pressure exceeds 0.3 MPa, the container swells greatly with the generation of gas, the power storage device is deformed, the active material is dropped from the electrode, cracks and the like are generated in the container, There is a high possibility that a malfunction such as a short circuit due to contact or contact between the tab and the end of the container will occur. If the pressure difference is less than 0.05 MPa, the valve device opens due to vibration or impact during normal use of the power storage device, causing leakage of the electrolyte (such as a decrease in the amount of the electrolyte) and deterioration of the sealing property (such as moisture). Is likely to deteriorate due to, for example, intrusion into the power storage device). The primary side of the valve device is a side located inside the housing of the power storage device, and the secondary side of the valve device is a side located outside the housing of the power storage device (that is, the external environment). is there. The valve device includes a secondary side located outside the housing of the power storage device (that is, an external environment) and a primary side located inside the housing of the power storage device. When the pressure inside the container increases due to the generated gas, the pressure is reduced (that is, the gas generated inside the container is released from the primary side to the secondary side). It is configured.

  The pressure difference between the primary side and the secondary side of the valve device (opening pressure of the valve device) may be set according to the type of the electric storage device within the above range, but the lower limit is 0.05 MPa or more. Preferably, the pressure is about 0.1 MPa or more, and the upper limit is about 0.3 MPa or less, preferably about 0.2 MPa, and the preferable ranges are about 0.05 to 0.2 MPa and 0.1 to 0. About 3 MPa, about 0.1 to 0.2 MPa are mentioned. When the differential pressure of the valve device is within these ranges, when gas is generated inside while maintaining the high sealing property of the power storage device, the gas can be more appropriately discharged to the outside. .

  The differential pressure when the primary side and the secondary side of the valve device are opened is measured by the following method.

<Method of measuring differential pressure between primary and secondary sides of valve device>
The valve device is installed on a measuring jig made of metal, a compressed air cylinder is installed on the primary side of the jig via a small pressure gauge, and a rubber tube is installed on the secondary side. Installed in At this time, it is confirmed in advance that there is no leakage from the jig or the contact. Air is gradually fed into the valve device from the air cylinder on the primary side, and the pressure at which bubbles start to be generated from the rubber tube of the water tank is read by a pressure gauge, and the differential pressure between the primary side and the secondary side of the valve device is measured.

In the power storage device of the present disclosure, it is preferable that the set pressure inside the housing is set to a certain pressure or less. The set value of the internal pressure is appropriately set according to the type of the electric storage device, but is preferably about 0.1 MPa or less, more preferably about 1.0 × 10 ⁻² MPa or less. 0 × least ¹⁰ -10 MPa, and examples of the preferred range of the internal pressure, 1.0 × ¹⁰ -10 ~0.1MPa ^{about, 1.0 × 10 -10 ~1.0 × 10} -2 MPa approximately Is mentioned.

  The differential pressure between the primary and secondary sides of the valve device (opening pressure of the valve device) can be set by a known method. For example, materials, shapes, and sizes of members (for example, a ball, a valve seat (for example, an O-ring), a spring, and a vent) to be described later that constitute a valve mechanism of the valve device, and a force of pressing the ball by the spring. , The differential pressure can be adjusted.

  In the housing of the power storage device according to the present disclosure, when the thickness of the heat-fusible resin layer that is located at the center of the housing and is not fused to each other is set to 100%, the heat that is located at the peripheral joint and faces the heat It is preferable that the ratio X of the thickness of one of the heat-fusible resin layers in the portion where the heat-fusible resin layers are fused to each other is in the range of 50 to 80%. When the thickness ratio X of the heat-fusible resin layer is in such a range, heat and pressure at the time of fusing the heat-fusible resin layer are appropriately applied to the heat-fusible resin layer. As a result, the sealing performance of the container at the peripheral joint can be improved. Further, by setting the thickness ratio X of the heat-fusible resin layer in such a range, the sealing required for, for example, a vehicle-mounted or stationary power storage device can be highly secured. When the ratio X of the thickness of the heat-fusible resin layer is 50% or more, the heat-fusible resin layer is excessively crushed at the time of sealing or cracks are generated in the heat-fusible resin layer, thereby lowering the insulation. It is less likely that sealing can be enhanced to a higher degree. On the other hand, when the thickness ratio X of the heat-fusible resin layer is 80% or less, the sealing between the heat-fusible resin layers is insufficient (that is, the collapse of the heat-fusible resin layer due to the seal is too small). ) Is suppressed, and the release of gas from between the fused heat-fusible resin layers instead of the valve device due to the rapid increase in the internal pressure is more suitably suppressed.

  The ratio X of the thickness of the heat-fusible resin layer is, for example, about 45% or more, preferably about 50% or more, more preferably about 60% or more for the lower limit, and about 95% or less for the upper limit. It is preferably about 80% or less, more preferably about 70% or less, and preferred ranges include about 50 to 80%, about 50 to 70%, about 60 to 80%, and about 60 to 70%. The ratio X of the thickness of the heat-fusible resin layer is a value calculated by measuring the thickness of the cross section of the heat-fusible resin layer.

  Further, in the housing of the power storage device of the present disclosure, when the thickness of the heat-fusible resin layer that is located at the center of the housing and is not fused to each other is set to 100%, the position where the valve device is sandwiched is provided. The ratio Y of the thickness of the heat-fusible resin layer has a lower limit of, for example, about 45% or more, more preferably about 60% or more, and an upper limit of, for example, about 95% or less, preferably about 90% or less. The preferred ranges include about 60 to 90%, about 70 to 90%, and about 80 to 90%. When the thickness ratio Y of the heat-fusible resin layer has such a value, the heat and the pressure for fusing the heat-fusible resin layer when the valve device is attached to the container are reduced by the heat-fusible resin. It is appropriately added to the layer, so that the sealing property of the container between the mounting portion of the valve device and the heat-fusible resin layer can be made appropriate. Further, by setting the thickness ratio Y of the heat-fusible resin layer to such a range, for example, when an abnormality such as thermal runaway occurs, a large amount of gas is generated in the housing at once, When the valve device is closed due to an abnormality in the valve mechanism, the gas is preferably discharged by preferentially opening the space between the mounting portion of the valve device and the heat-fusible resin layer instead of the valve device. Can be. If the ratio Y of the thickness of the heat-fusible resin layer is less than 60%, the sealing property between the mounting portion of the valve device and the heat-fusible resin layer is too high (that is, heat-sealing by the seal). It is difficult to release gas from between the mounting portion of the valve device and the heat-fusible resin layer in the event of thermal runaway or the like. On the other hand, when the ratio Y of the thickness of the heat-fusible resin layer exceeds 90%, the sealing property between the mounting portion of the valve device and the heat-fusible resin layer is insufficient (that is, the heat-fusible resin layer by the seal). Is too small), and the possibility of leakage of the electrolyte or the like increases. The ratio Y is calculated using the maximum thickness of the heat-fusible resin layer at the position sandwiching the valve device.

  In the housing of the power storage device of the present disclosure, it is preferable that the thickness ratio Y of the heat-fusible resin layer is larger than the thickness ratio X of the heat-fusible resin layer. In this way, for example, when a large amount of gas is generated inside the container at a stretch at the time of abnormality such as thermal runaway, or when the valve device is closed due to an abnormality of the valve mechanism of the valve device, the valve is replaced with the valve device. The gas can be preferably released by preferentially opening the space between the mounting portion of the device and the heat-fusible resin layer.

  Further, in the housing of the electricity storage device according to the present disclosure, the peel strength X between the heat-fusible resin layers in the portion where the heat-fusible resin layers opposed to each other are located at the peripheral joint portion and are fused to each other is a valve. It is preferable that the peel strength between the heat-fusible resin layer and the valve device at the position sandwiching the device is larger than the peel strength Y. In this way, for example, when a large amount of gas is generated inside the container at a stretch at the time of abnormality such as thermal runaway, or when the valve device is closed due to an abnormality of the valve mechanism of the valve device, the valve is replaced with the valve device. The gas can be preferably released by preferentially opening the space between the mounting portion of the device and the heat-fusible resin layer. The difference (X-Y) between the peel strength X and the peel strength Y is preferably about 5 N / 15 mm or more for the lower limit, more preferably about 10 N / 15 mm or more, and about 40 N / 15 mm or less for the upper limit. Is about 5 to 40 N / 15 mm, more preferably about 10 to 40 N / 15 mm.

  The peel strengths X and Y are such that the pressure difference between the primary side and the secondary side of the valve device is set within the range of 0.05 MPa or more and 0.3 MPa or less so that the container can be properly sealed. I just need. The peel strength X preferably has a lower limit of about 75 N / 15 mm or more, more preferably about 100 N / 15 mm or more, and an upper limit of about 150 N / 15 mm or less, more preferably about 130 N / 15 mm or less. Preferred ranges include about 75 to 150 N / 15 mm, about 75 to 130 N / 15 mm, about 100 to 150 N / 15 mm, and about 100 to 130 N / 15 mm. The peel strength Y has a lower limit of preferably about 70 N / 15 mm or more, more preferably about 90 N / 15 mm or more, and an upper limit of preferably about 130 N / 15 mm or less, more preferably about 115 N / 15 mm. The following are preferable, and preferable ranges include about 70 to 130 N / 15 mm, about 70 to 115 N / 15 mm, about 90 to 130 N / 15 mm, and about 90 to 115 N / 15 mm.

<Measurement of peel strength X, Y>
The peel strengths X and Y are measured in a 25 ° C. environment in accordance with JIS K7127: 1999. First, for the measurement of the peel strength X, a test piece is obtained by cutting the heat-fusible resin layer of each test sample so that the width becomes 15 mm from the heat-sealed portion. In the measurement of the peel strength Y, in a state where the valve device of each test sample and the heat-fusible resin layer were fused, the heat-fusible resin layer was cut so as to have a width of 5 mm, and the test piece was cut. Get. Next, each test piece is peeled off the heat-fusible resin layer by 4 mm at a speed of 300 mm / min using a tensile tester (eg, AG-Xplus, manufactured by Shimadzu Corporation). The maximum strength at the time of peeling was defined as peel strength (N / 15 mm). Since the peel strength Y is measured at a width of 5 mm, a value obtained by multiplying the actually measured value by 3 is defined as the peel strength Y (N / 15 mm). The distance between the chucks is 50 mm, and the peeling angle is 180 degrees. Each is an average value measured three times.

  Further, the tensile strength of the packaging material constituting the container is preferably about 100 to 200 N / 15 mm. With such a tensile breaking strength, the container can withstand a large weight of, for example, a medium-sized or large-sized power storage device for use in a vehicle or stationary. The tensile breaking strength of the packaging material is a value measured as follows.

<Method of measuring tensile breaking strength of packaging material>
The tensile breaking strength in the MD (Machine Direction) and the TD (Transverse Direction) of the exterior material for a power storage device is measured using a tensile tester (for example, AG-Xplus, manufactured by Shimadzu Corporation) in accordance with the method of JIS K7127. I do. The measurement conditions are a rectangular shape with a sample width of 15 mm, a distance between marked lines of 30 mm, a tensile speed of 100 mm / min, a test environment of 23 ° C., and an average value measured three times. The MD of the exterior material for the power storage device corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the exterior material for the power storage device corresponds to the TD of the aluminum alloy foil. The rolling direction (RD) can be determined by the rolling line. When the MD of the exterior material for a power storage device cannot be specified by the rolling stitches of the aluminum alloy foil, the MD can be specified by the following method. As a method for confirming the MD of the exterior material for a power storage device, the cross section of the heat-fusible resin layer of the exterior material for a power storage device is observed with an electron microscope to confirm the sea-island structure, and the perpendicular to the thickness direction of the heat-fusible resin layer The direction parallel to the cross section where the average of the diameters of the island shapes in the directions is the largest can be determined as MD. Specifically, the angle of the cross-section in the length direction of the heat-fusible resin layer and the direction parallel to the cross-section in the length direction are changed by 10 degrees each, and each angle is changed to a direction perpendicular to the cross-section in the length direction. The cross-section (total of 10 cross-sections) is observed with an electron micrograph to confirm the sea-island structure. Next, in each cross section, the shape of each individual island is observed. Regarding the shape of each island, the straight line distance between the leftmost end in the direction perpendicular to the thickness direction of the heat-fusible resin layer and the rightmost end in the vertical direction is defined as a diameter y. In each section, the average of the top 20 diameters y is calculated in descending order of the diameter y of the island shape. The direction parallel to the cross section where the average of the diameter y of the island shape is the largest is determined as MD.

  Hereinafter, preferred embodiments of the valve device attached to the power storage device of the present disclosure, the structure of the power storage device, and the like will be described.

  Preferably, the valve device includes a first part and a second part. The first portion is a portion in which a valve mechanism for reducing the pressure when the pressure inside the container increases due to the gas generated inside the container is formed inside. The second portion is a portion in which a ventilation path for guiding gas generated inside the container to the valve mechanism is formed.

  The container of the power storage device of the present disclosure is configured by a laminate having at least a base layer, a barrier layer, and a heat-fusible resin layer in this order, and at the periphery of the container, the heat-fusible resin layer Are facing each other. On the periphery of the container, there is formed a peripheral joint where the opposite heat-fusible resin layers are fused to each other. In the valve device, the first portion is preferably located outside the edge of the peripheral joint. Further, at least a part of the second portion is sandwiched between the heat-fusible resin layers at the peripheral joining portion.

  In this power storage device, it is the second portion of the valve device that is sandwiched between the heat-fusible resin layers at the peripheral joining portion, and the first portion of the valve device is not sandwiched between the heat-fusible resin layers. Is preferred. In this electric storage device, a large pressure and heat are not applied to the first portion compared to the second portion when the opposing heat-fusible resin layers are fused. As a result, according to the valve device for an electric storage device, it is possible to suppress the failure of the valve mechanism in the first portion due to the pressure and heat applied when the opposing heat-fusible resin layers are fused.

  Preferably, in the thickness direction of the power storage device, the length of the first portion is longer than the length of the second portion, and a step may be formed at a boundary between the first portion and the second portion.

  In this power storage device, it is preferable that the first portion is longer than the second portion at least in the thickness direction of the power storage device, and that a step is formed at a boundary between the first portion and the second portion. Therefore, in this power storage device, when the second portion is sandwiched between the heat-fusible resin layers in the process of manufacturing the power storage device, even if the valve device is pushed too far into the housing, the step portion is caught on the end of the laminate. . Therefore, according to the power storage device, it is possible to suppress a situation in which the first portion is erroneously sandwiched between the heat-fusible resin layers in the process of manufacturing the power storage device. Further, in this electric storage device, the thickness of the electric storage device at the portion where the second portion is sandwiched in the peripheral joint portion is compared with the case where no step is provided at the boundary between the first portion and the second portion. The difference between the length in the thickness direction and the length in the thickness direction of the power storage device in a portion where the second portion is not sandwiched among the peripheral edge joints is small. Therefore, in the portion where the second portion is sandwiched between the peripheral edge joining portions, the heat-fusible resin layers are fused to each other without applying excessive heat and pressure to the heat-fusible resin layers. As a result, according to this electric storage device, it is possible to suppress a decrease in seal strength and a decrease in insulation due to a reduction in the thickness of the heat-fusible resin layer. Here, the decrease in insulation property is a phenomenon in which a current is generated between the barrier (metal) layer and the electrolyte due to partial thinning or cracking of the heat-fusible resin.

  Preferably, the length of the second portion in the width direction of the power storage device may be longer than the length of the second portion in the thickness direction of the power storage device.

  In this power storage device, the length of the second portion in the thickness direction of the power storage device is shorter than when the cross-sectional shape of the second portion is a perfect circle (having the same area). In other words, in this power storage device, the length in the thickness direction of the power storage device at the portion where the second portion is sandwiched among the peripheral junctions, and the length of the power storage device at the portion where the second portion is not sandwiched among the peripheral junctions The difference from the length in the thickness direction is small. Therefore, in the portion where the second portion is sandwiched between the peripheral edge joining portions, the heat-fusible resin layers are fused to each other without applying excessive heat and pressure to the heat-fusible resin layers. As a result, according to this power storage device, it is possible to suppress a decrease in seal strength and a decrease in insulation due to the thinning of the heat-fusible resin layer.

  In addition, particularly preferably, the second portion has a wing-shaped extending end portion that is formed thinner as approaching an end portion in the width direction of the power storage device.

  In this power storage device, as compared with the case where the wing-shaped extended end portion is not provided in the second portion, the portion of the peripheral joint where the second portion is not interposed is sandwiched from the portion where the second portion is not interposed. The change in the thickness direction of the power storage device at the position where the power storage device moves to the portion where the power storage device moves is smooth. Therefore, no excessive force is applied to the laminate at the boundary between the position where the second portion is sandwiched between the heat-fusible resin layers and the position where the second portion is not sandwiched between the heat-fusible resin layers. As a result, according to this electricity storage device, it is possible to appropriately fuse the heat-fusible resin layer without applying an excessive amount of heat or pressure to the heat-fusible resin layer. In addition, it is possible to suppress a decrease in insulation.

  Preferably, the cross-sectional shape of the ventilation path may be circular.

  Preferably, a cross-sectional length of the ventilation path in a width direction of the power storage device may be longer than a cross-sectional length of the ventilation path in a thickness direction of the power storage device.

  Further, the second portion may have a pillar formed in the ventilation path.

  When pillars are formed in the ventilation path of the second portion, the ventilation path is maintained even if pressure and heat are applied to the second portion sandwiched between the opposing heat-fusible resin layers. Therefore, according to this power storage device, it is possible to suppress breakage of the air passage in the second portion when the opposing heat-fusible resin layers are fused.

  Preferably, the outer surface of the second portion may be a pear.

  In this power storage device, since the outer surface of the second portion is a pear ground, the heat-fusible resin easily melts at a position in contact with the second portion. Therefore, according to this power storage device, the second portion of the valve device can be firmly fixed to the housing as compared with the case where the outer surface of the second portion is smooth.

  Preferably, at least one ridge extending in the circumferential direction may be formed on the outer surface of the second portion.

  Since the protruding portion surely contacts the heat-fusible resin layer, it is easy to fuse to the laminate. In this electric storage device, the convex portion extends in the circumferential direction on the outer surface of the second portion. Therefore, according to this power storage device, the heat-fusible resin layer and the second portion can be fused in the circumferential direction of the second portion. Further, in this electric storage device, the contact area between the outer surface of the second portion and the heat-fusible resin is larger than that in the case where the convex portion is not formed in the second portion. Therefore, according to this power storage device, the second portion of the valve device can be relatively firmly fixed to the housing. In addition, by providing a plurality of ridges, it is possible to further firmly fix the second portion to the container.

  Also, preferably, in the second portion, the corner of the end portion on the opposite side to the first portion side in plan view may be rounded.

  According to this power storage device, for example, when the end opposite to the first portion is located inside the housing, the possibility that the end damages the power storage device element in the housing is reduced. Can be. Further, according to the power storage device, the possibility that the end portion damages the heat-fusible resin layer inside the container and reduces the insulating property of the heat-fusible resin layer can be reduced.

  Also, preferably, the outer shape of the cross section of the second portion having the normal to the center line of the ventilation path is a polygon, and the corners of the polygon may be rounded.

  According to this power storage device, for example, when the end of the second portion opposite to the first portion is located inside the housing, the portion of the second portion located in the housing is located inside the housing. The possibility of damaging the power storage device element can be reduced, and the portion of the second portion sandwiched between the heat-fusible resin layers damages the heat-fusible resin layers, The possibility of lowering the insulation of the device can be reduced. Further, according to the power storage device, for example, when the end of the second portion opposite to the first portion is sandwiched by the heat-fusible resin layer, the second portion is heat-fusible. The possibility of damaging the resin layer and reducing the insulating property of the heat-fusible resin layer can be reduced.

  Preferably, each of the first portion and the second portion is made of a different material, and the melting point of the material of the first portion may be higher than the melting point of the material of the second portion. The material of the first portion and the second portion is not particularly limited, and for example, resins such as polypropylene (PP), fluorine resin, polyester resin, polyimide resin, polycarbonate resin, acrylic resin, stainless steel, Metals such as aluminum are mentioned.

  In this power storage device, even if pressure and heat are applied to the second portion during fusion of the opposing heat-fusible resin layers, the melting point of the material of the first portion is higher than the melting point of the material of the second portion. Therefore, the possibility that the first portion is deformed by heat is low. Therefore, according to this power storage device, it is possible to suppress the failure of the valve mechanism in the first portion at the time of fusing the opposed heat-fusible resin layers.

  Preferably, a flat surface may be formed on at least a part of the outer surface of at least one of the first portion and the second portion.

  In this electric storage device, since the flat surface is formed on the outer surface of the valve device, the rolling of the valve device is prevented. Therefore, according to this power storage device, the valve device does not roll when the valve device is attached to the housing, so that the valve device can be easily positioned.

  Hereinafter, specific embodiments of the power storage device and the valve device according to the present disclosure will be exemplified. However, the power storage device and the valve device of the present disclosure are not limited to the following.

[1. Embodiment 1]
<1-1. Overview of power storage devices>
FIG. 1 is a plan view of an electric storage device 10 according to the first embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. The power storage device 10 has a configuration in which the positive electrode and the negative electrode of the tab 300 are arranged on opposite sides, and is designed for an electric vehicle such as an electric vehicle or a hybrid vehicle that uses a large number of power storage devices connected in series and uses a high voltage. .

  As shown in FIGS. 1 and 2, the power storage device 10 includes a housing 100, a power storage device element 400, a tab 300, a tab film 310, and a valve device 200. The container 100 has a rectangular shape in a plan view, and the valve device 200 is located at a position different from the side where the tab 300 of the container 100 exists. For example, in a medium-sized or large-sized power storage device for in-vehicle use or stationary use, the valve device 200 is preferably provided on the periphery of the container 100 in order to stack the cells into a module. Furthermore, when the valve device 200 is attached to the same side as the side where the tab 300 is located in the container 100 having a rectangular shape in a plan view, the tab 300 and the valve device 200 can be attached at the same time. I have. On the other hand, as shown in FIG. 1, when the valve device 200 is attached to a side different from the side where the tab 300 is located, when the gas is discharged from the valve device 200 to the outside, the gas adheres to the tab 300 and the connection of the tab 300 is performed. And the like.

  The container 100 includes packaging materials 110 and 120. At the periphery of the container 100, the packaging materials 110 and 120 are heat-sealed to form a peripheral joint 130. That is, in the peripheral joint portion 130, the packaging materials 110 and 120 are fused to each other. The packaging materials 110 and 120 will be described later in detail.

  Power storage device element 400 is, for example, a power storage member such as a lithium ion power storage device or a capacitor. The power storage device element 400 is housed inside the housing 100. When an abnormality occurs in the power storage device element 400, gas may be generated in the housing 100. Further, for example, when power storage device element 400 is a capacitor, gas may be generated in container 100 due to a chemical reaction in the capacitor.

  The tab 300 is a metal terminal used for input and output of power in the power storage device element 400. One end of the tab 300 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 400, and the other end protrudes outward from an edge of the housing 100.

  The metal material forming the tab 300 is, for example, aluminum, nickel, copper, or the like. For example, when power storage device element 400 is a lithium-ion power storage device, tab 300 connected to the positive electrode is usually made of aluminum or the like, and tab 300 connected to the negative electrode is usually made of copper, nickel, or the like. You.

  The power storage device 10 includes two tabs 300. One tab 300 is sandwiched between packaging materials 110 and 120 via a tab film 310 at an end of the container 100 in the direction of the arrow L. The other tab 300 is sandwiched between packaging materials 110 and 120 via a tab film 310 at an end of the container 100 in the direction of arrow R.

  The tab film 310 is an adhesive protective film, and is configured to adhere to both the packaging materials 110 and 120 and the tab 300 (metal). By interposing the tab film 310, the metal tab 300 can be fixed with the packaging materials 110 and 120. Further, when the tab film 310 is used particularly at a high voltage, it is preferable that the tab film 310 contains a heat-resistant layer or a heat-resistant component and has a short-circuit preventing function.

  The valve device 200 communicates with the inside of the container 100, and when the pressure in the container 100 becomes equal to or higher than a predetermined value due to the gas generated in the container 100, the gas in the container 100. To the outside. The casing of the valve device 200 is preferably made of a material that directly adheres to the innermost layers of the packaging materials 110 and 120, and a resin having the same heat-fusing property as the innermost layers of the packaging materials 110 and 120, for example, polypropylene (PP). And the like. If a different material other than PP is used for reasons such as heat resistance, a method in which a film that can be bonded to both the different material and PP is interposed and sealed as in the case of the tab film used for the tab is effective. . The end of the valve device 200 in the direction of arrow B is sandwiched between the packaging materials 110 and 120 at the end of the container 100 in the direction of arrow F. The valve device 200 will be described later in detail.

  In power storage device 10 according to the first embodiment, various structural devices are employed to attach valve device 200 to housing 100. Hereinafter, the configuration of the container 100, the configuration of the valve device 200, the state of attachment of the valve device 200 to the container 100, and the method of manufacturing the power storage device 10 will be sequentially described.

  Note that the direction indicated by each of the arrows LRUDFB is common in each drawing. Hereinafter, the direction of arrow LR is also referred to as “the width direction of power storage device 10”, and the direction of the arrow UD is also referred to as “the thickness direction of power storage device 10”.

<1-2. Configuration of container>
FIG. 3 is a diagram illustrating the container 100. As shown in FIG. 3, the container 100 includes packaging materials 110 and 120. Each of the packaging materials 110 and 120 is formed of a so-called laminate film, and has a substantially identical rectangular shape in plan view.

  The packaging material 110 includes a molded portion 112 molded so as to form the space S1, and a flange portion 114 extending from the molded portion 112 in the arrow FB direction and the arrow LR direction. In the forming part 112, the surface in the direction of the arrow U is open. Power storage device element 400 (FIG. 1) is arranged in space S1 through the open surface.

  FIG. 4 is a diagram illustrating an example of a cross-sectional structure of the packaging materials 110 and 120. As shown in FIG. 4, each of the packaging materials 110 and 120 is a laminate in which a base material layer 31, an adhesive layer 32, a barrier layer 33, an adhesive layer 34, and a heat-fusible resin layer 35 are laminated in this order. It is. In addition, each of the packaging materials 110 and 120 does not necessarily need to include each layer shown in FIG. 4, as long as it has at least the base layer 31, the barrier layer 33, and the heat-fusible resin layer 35 in this order. Good.

  In the container 100, the base material layer 31 is on the outermost layer side, and the heat-fusible resin layer 35 is on the innermost layer. At the time of assembling the electric storage device 10, the heat-fusible resin layers 35 located on the periphery of each of the packaging materials 110 and 120 in a state where the electric storage device element 400 (FIG. 2) is arranged in the space S1 (FIG. 3). Is thermally fused to form a peripheral joint 130, the power storage device element 400 is sealed in the housing 100, the valve device 200 is fused and fixed to the peripheral joint 130, and the tab 300 is also It is fused and fixed to the peripheral joining portion 130 via the tab film 310. Hereinafter, each layer included in the packaging materials 110 and 120 will be described. The thickness of the packaging materials 110 and 120 is, for example, about 50 to 250 μm, and preferably about 90 to 200 μm.

(1-2-1. Base material layer)
The base material layer 31 is a layer that functions as a base material of the packaging materials 110 and 120, and is a layer that forms the outermost layer side of the container 100.

  The material for forming the base layer 31 is not particularly limited as long as it has insulating properties. Examples of the material forming the base layer 31 include polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, polycarbonate, and mixtures and copolymers thereof. . The base layer 31 may be, for example, a resin film formed of the above resin, or may be formed by applying the above resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of a stretching method for forming a biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Furthermore, the base material layer 31 may be a single layer, or may be composed of two or more layers. When the base layer 31 is composed of two or more layers, the base layer 31 may be a laminate in which a resin film is laminated with an adhesive or the like, or may be formed by co-extruding a resin and forming two or more layers. It may be a laminated body of a resin film obtained. Further, a laminate of two or more resin films obtained by co-extrusion of a resin may be used as the base material layer 31 without stretching, or may be used as the base material layer 31 by uniaxial stretching or biaxial stretching. As a specific example of the laminate of the resin film in which the base material layer 31 is two or more layers, a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, a laminate of two or more polyester films Preferred are a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films. For example, when the base layer 31 is a laminate of a two-layer resin film, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film. A laminate is preferable, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferable. Further, it is preferable that the polyester resin is located in the outermost layer of the base material layer 31.

  The thickness of the base material layer 31 is, for example, about 3 to 50 μm, preferably about 10 to 35 μm.

(1-2-2. Adhesive layer)
The adhesive layer 32 is a layer that is disposed as necessary on the base layer 31 in order to firmly adhere the base layer 31. That is, the adhesive layer 32 is provided between the base layer 31 and the barrier layer 33 as needed.

  The adhesive layer 32 is formed of an adhesive capable of adhering the base layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-part curable adhesive or a one-part curable adhesive. The bonding mechanism of the adhesive used for forming the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent evaporation type, a hot-melt type, and a thermocompression bonding type.

  The thickness of the adhesive layer 32 is, for example, about 1 to 10 μm, preferably about 2 to 5 μm.

(1-2-3. Barrier layer)
The barrier layer 33 is a layer that has a function of preventing the invasion of water vapor, oxygen, light, and the like into the power storage device 10 in addition to improving the strength of the packaging materials 110 and 120. Examples of the metal forming the barrier layer 33 include aluminum, stainless steel, titanium, and the like, and preferably aluminum. The barrier layer 33 can be formed of, for example, a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, and a film provided with these vapor-deposited films. Preferably, it is more preferably formed of aluminum foil. From the viewpoint of preventing generation of wrinkles and pinholes in the barrier layer 33 during the production of each packaging material, the barrier layer is made of, for example, annealed aluminum (JIS H4160: 1994 A8021H-O, JIS H4160: 1994). A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O) and the like are more preferably formed of a soft aluminum foil.

  It is particularly preferable that the barrier layer 33 is made of an aluminum foil having an average crystal grain size of 20 μm or less. Such an aluminum foil is excellent in formability. The average crystal grain size of the aluminum foil was obtained by observing a cross section in the thickness direction of the aluminum foil with a scanning electron microscope (SEM), and regarding the crystal grains 33a of 100 aluminum alloys located in the visual field, as shown in the schematic diagram of FIG. As shown, when the maximum distance x is a straight line distance connecting the leftmost end in the vertical direction with the thickness direction of each crystal grain and the rightmost end in the vertical direction with the thickness direction, the corresponding 100 It means the average value of the maximum diameter x. Since FIG. 31 is a schematic diagram, the drawing is omitted and 100 crystal grains 33a are not drawn.

  The thickness of the barrier layer 33 is not particularly limited as long as it functions as a barrier layer for water vapor or the like, but can be, for example, about 10 to 100 μm, preferably about 30 to 100 μm, and more preferably about 20 to 80 μm. When the power storage device is a medium-sized or large-sized power storage device such as an in-vehicle device or a stationary device, the barrier layer 33 is formed from the viewpoint of securing a high strength while forming a sufficiently large molded portion in the container. Is preferably about 30 to 100 μm.

(1-2-4. Adhesive layer)
The adhesive layer 34 is a layer provided as needed between the barrier layer 33 and the heat-fusible resin layer 35 in order to firmly adhere the heat-fusible resin layer 35.

  The adhesive layer 34 is formed of an adhesive capable of adhering the barrier layer 33 and the heat-fusible resin layer 35. The composition of the adhesive used to form the adhesive layer 34 is not particularly limited, but is, for example, a resin composition containing an acid-modified polyolefin. The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferably includes a polyolefin graft-modified with an unsaturated carboxylic acid or an anhydride thereof.

  The thickness of the adhesive layer 34 is, for example, about 1 to 50 μm, preferably about 2 to 40 μm.

(1-2-5. Heat-fusible resin layer)
The heat-fusible resin layer 35 forms the innermost layer of the container 100. The heat-fusible resin layer 35 is heat-sealed with the opposing heat-fusible resin layer at the periphery of the container 100 to seal the power storage device element 400 in the container 100. Further, by covering the barrier layer with the heat-fusible resin with a certain film thickness or more, insulation between the electrolytic solution and the metal as the barrier layer can be maintained.

  The resin component used in the heat-fusible resin layer 35 is not particularly limited as long as it can be heat-fused, and is, for example, a polyolefin, an acid-modified polyolefin, or the like.

  Examples of the polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; homopolypropylene, block copolymers of polypropylene (eg, block copolymers of propylene and ethylene), and random copolymers of polypropylene ( For example, crystalline or non-crystalline polypropylene such as a random copolymer of propylene and ethylene); ethylene-butene-propylene terpolymer; and the like. Among these polyolefins, polyethylene and polypropylene are preferred. The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferably includes a polyolefin graft-modified with an unsaturated carboxylic acid or an anhydride thereof.

  Further, the thickness of the heat-fusible resin layer 35 is not particularly limited, but from the viewpoint of enhancing the sealing performance of a medium-sized or large-sized power storage device such as a vehicle-mounted or stationary device, the lower limit is preferably 30 μm or more. More preferably, the upper limit is 50 μm or more, and the upper limit is preferably 100 μm or less, more preferably 90 μm or less, even more preferably 80 μm or less, and the preferable range is about 30 to 100 μm, about 30 to 90 μm, or 30 to About 80 μm, about 50 to 100 μm, about 50 to 90 μm, about 50 to 80 μm. When the heat-fusible resin layer 35 is composed of a plurality of layers, the total thickness is preferably equal to these thicknesses. If the thickness of the heat-fusible resin layer is less than 30 μm, the sealing performance of a medium-sized or large-sized power storage device may be reduced.If the thickness exceeds 100 μm, the amount of the heat-fusible resin layer crushed during sealing increases. A part where the crushed heat-fusible resin layer is greatly extruded is formed inside the container, and this part becomes a starting point of a crack, and the possibility of lowering the insulating property increases.

  In the heat-fusible resin layer, it is preferable that a melting peak is observed in a range of 150 to 165 ° C when measured by a differential scanning calorimeter. Medium- and large-sized power storage devices, such as those for in-vehicle use and stationary use, have large capacities. Further, the capacitor is capable of inputting and outputting a large current and a high output. Therefore, these power storage devices tend to generate heat as compared with, for example, a mobile battery and the like, and may have a high installation environment. By observing the melting peak of the heat-fusible resin layer in the above range, it is possible to ensure sufficient adhesion of the heat-fusible resin layer even in these power storage devices.

<1-3. Configuration of Valve Device>
FIG. 5 is a plan view of the valve device 200. FIG. As shown in FIG. 5, the valve device 200 includes a valve function unit 210 and a seal mounting unit 220. Although the details will be described later, at least a part of the seal mounting portion 220 is a portion that is fixed by being sandwiched between the packaging materials 110 and 120 (FIG. 2). The outer peripheral surface of 220 and the heat-fusible resin layer 35 which is the innermost layer of the packaging materials 110 and 120 are in a state of being fused and joined.

  In the seal mounting portion 220, R is formed at the corner of the end in the direction of arrow B. That is, in the seal mounting portion 220, R (for example, R = 0.2 mm to 2.0 mm) is formed at the corner of the end opposite to the valve function portion 210 side in plan view. In the present disclosure, rounded corners are expressed as “R is formed”. Here, “R is formed” means a state in which the corner is rounded similarly to the case where chamfering is performed, and further, “R” alone is Used to mean radius of rounded corners. It should be noted that the sharp corner generated in the manufacturing process of the valve device 200 may be chamfered to round the corner (form R), but the casing of the valve device 200 is formed of a resin molded product. In the case of R, it is also possible to form R without chamfering such as cutting by shaping from the beginning so as to have rounded corners.

  FIG. 6 is a sectional view taken along line VI-VI of FIG. As shown in FIG. 6, in the valve device 200, the cross section of each of the valve function part 210 and the seal attachment part 220 is a perfect circle, and a ventilation path A1 is formed inside the seal attachment part 220. The cross section of the ventilation path A1 is a perfect circle.

  In the valve device 200, the length L2 of the valve function unit 210 in the thickness direction (the direction of the arrow UD) of the power storage device 10 is longer than the length L1 of the seal attachment unit 220 in the thickness direction of the power storage device 10. The length L2 of the valve function unit 210 in the width direction (the direction of the arrow LR) of the power storage device 10 is longer than the length L1 of the seal attachment unit 220 in the width direction of the power storage device 10. That is, the cross-sectional diameter of the valve function section 210 is longer than the cross-sectional diameter of the seal mounting section 220. As a result, a step is formed at the boundary between the valve function part 210 and the seal mounting part 220 (FIG. 5).

  FIG. 7 is a sectional view taken along line VII-VII of FIG. As shown in FIG. 7, R (for example, R = 0.2 mm to 2.0 mm) is formed at the end of the seal mounting portion 220 in the direction of arrow B. Further, a ventilation path A1 is formed inside the seal mounting portion 220. The ventilation path A1 guides, for example, gas generated in the container 100 to the valve function unit 210.

  A valve mechanism configured to discharge gas generated in the container 100 (FIG. 1) is provided inside the valve function unit 210. Specifically, the valve function unit 210 includes a valve seat 212, a ball 214, a spring 216, and a membrane 218. That is, the valve function section 210 is provided with a ball spring type valve mechanism. In addition, the valve mechanism provided in the valve function unit 210 is not particularly limited as long as the pressure in the container 100 that has risen due to the gas can be reduced. For example, a poppet type, a duckbill type, an umbrella type, a diaphragm It may be a valve mechanism such as a mold. In addition, the valve seat 212 may be, for example, an O-ring, or a portion of the valve function unit 210 that contacts the ball 214 may be the valve seat 212. When a part of the valve function part 210 is used as the valve seat 212, the valve function part 210 and the valve seat 212 are integrated.

The valve seat is made of an elastic material such as fluorine rubber, a metal such as stainless steel, a resin, or the like. The surface of the valve seat may be coated with PTFE or the like. Further, the ball 214 may be made of an elastic material such as fluoro rubber. The ball 214 may be made of metal such as stainless steel or resin. The spring 216 is made of, for example, stainless steel. Membrane 218, for example, ^10-2 have to 10 ⁰ [mu] m approximately pore diameter (pore For diameter), without leaking the electrolyte is composed of a PTFE membrane as the only gas permeable (permselective). In addition, PTFE means polytetrafluoroethylene (polytetrafluoroethylene). In addition, since the PTFE membrane is a soft material, if the strength is insufficient, a PTFE membrane that is integrally molded with a mesh or nonwoven fabric of polypropylene or polyester and reinforced can be used. Note that, for example, FIG. 7 and the like show a diagram in which the membrane 218 is provided in the valve function unit 210. However, from the viewpoint of suppressing intrusion of a liquid (for example, an electrolytic solution) into the valve function unit 210, the membrane 218 is used. 218 is preferably provided in the seal attachment part 220 (for example, the ventilation path A1). When an electrolytic solution or the like adheres to the valve function unit 210, the valve function may be impaired due to crystallization of a salt component of the electrolytic solution.

  When the pressure in the container 100 reaches a predetermined pressure in a state where the valve device 200 is attached to the container 100, the gas guided from the ventilation path A1 presses the ball 214 in the direction of arrow F. When the ball 214 is pressed and the spring 216 contracts, the gas in the container 100 passes through a gap formed between the ball 214 and the valve seat 212, passes through the membrane 218, and passes through the exhaust port O 1 through the container 100. Is discharged to the outside.

<1-4. Mounting condition of valve device>
FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. As shown in FIG. 8, the valve function unit 210 of the valve device 200 is located outside the edge of the peripheral joint 130. On the other hand, a part of the seal mounting portion 220 of the valve device 200 is sandwiched between the heat-fusible resin layer 35 of the packaging material 110 and the heat-fusible resin layer 35 of the packaging material 120 at the peripheral joining portion 130. In this state, the outer peripheral surface of the seal mounting portion 220 and the heat-fusible resin layer 35 as the innermost layer of the packaging materials 110 and 120 are fused and joined. In FIG. 8, the valve device 200 is described as being in a state of being fused and joined to the heat-fusible resin layer 35 which is the innermost layer of the packaging materials 110 and 120. Although the adhesive resin layer 35 is partially illustrated only in the vicinity of the peripheral joining portion 130, the heat-fusible resin layer 35 is provided on the entire surfaces of the packaging materials 110 and 120.

  In power storage device 10 according to the first embodiment, seal attaching portion 220 is sandwiched between heat-fusible resin layers 35 at peripheral joining portion 130, and valve function portion 210 is attached to heat-fusible resin layer 35 at peripheral joining portion 130. The reason for not being sandwiched is described below.

  It is assumed that the valve function section 210 is sandwiched between the heat-fusible resin layers 35 at the peripheral joining section 130. In this case, when the heat-fusible resin layers 35 are fused (heat-sealed) to each other at the peripheral edges of the packaging materials 110 and 120, the valve mechanism in the valve function unit 210 fails due to the applied heat and pressure. there's a possibility that.

  In power storage device 10 according to the first embodiment, seal attachment portion 220 is sandwiched between heat-fusible resin layers 35 at peripheral joining portion 130, and valve function unit 210 is attached to heat-fusible resin layer 35. Not sandwiched. Therefore, in the power storage device 10, large pressure and heat are not applied to the valve function unit 210 during heat sealing. That is, in the electricity storage device 10, failure of the valve mechanism due to pressure and heat applied at the time of heat sealing is suppressed by not sandwiching the valve function unit 210 between the heat-fusible resin layers 35.

  Further, in power storage device 10 according to the first embodiment, as described above, the diameter of the cross section of seal mounting portion 220 is shorter than the diameter of the cross section of valve function portion 210. Therefore, as compared with the case where the cross-sectional diameter of the seal mounting portion 220 is equal to or greater than the cross-sectional diameter of the valve function portion 210, the thickness direction of the power storage device in the portion of the peripheral joining portion 130 where the seal mounting portion 220 is sandwiched. Is small, and the length L3 in the thickness direction of the power storage device in a portion of the peripheral joining portion 130 where the seal attachment portion 220 is not sandwiched is small. The larger the difference, the more the outer peripheral surface of the seal attachment portion 220 is fused to the heat-fusible resin layer 35, which is the innermost layer of the packaging materials 110 and 120, so that the outer peripheral surface is joined without gaps. It is necessary to increase the pressure of the seal. As a result, the pressure applied to the periphery of the container 100 for heat sealing increases. When the pressure is increased, the heat-fusible resin layer 35 may be thinner particularly at the position where the seal attachment portion 220 is sandwiched, and further at the position where the tab film 310 and the tab 300 are sandwiched. When the heat-fusible resin layer 35 becomes thin, dielectric breakdown may occur in the power storage device 10.

  In power storage device 10 according to the first embodiment, as described above, the difference between length L4 and length L3 is small. Therefore, when the periphery of the container 100 is sandwiched by the heat sealing machine, pressure and heat are appropriately applied to the heat-fusible resin layer 35 over the entire periphery of the container 100. As a result, according to the power storage device 10, the opposing heat-fusible resin layer 35 is appropriately fused while reducing the possibility of dielectric breakdown occurring in the power storage device 10, and the seal attachment portion 220 is attached to the container 100. Can be fixed firmly.

  Further, in power storage device 10 according to the first embodiment, the end of seal mounting portion 220 in the direction of arrow B protrudes into space S1 beyond flange 114. Therefore, the end of the seal mounting portion 220 in the direction of arrow B may come into contact with the power storage device element 400 depending on the usage state of the power storage device 10. In power storage device 10 according to the first embodiment, R is formed at the end of seal mounting portion 220 in the direction of arrow B as described above (FIG. 5). Therefore, even if the end of the seal attaching portion 220 contacts the power storage device element 400, the possibility that the end damages the power storage device element 400 is low. In addition, depending on the usage state of the power storage device 10, the end of the seal attachment portion 220 in the direction of arrow B may come into contact with the heat-fusible resin layer 35 of the packaging material 120. In power storage device 10 according to the first embodiment, as described above, R is formed at the end of seal mounting portion 220 in the direction of arrow B, so that the end of seal mounting portion 220 is temporarily Even if the edge contacts the heat-fusible resin layer 35, the possibility that the end portion damages the heat-fusible resin layer 35 is low.

<1-5. Manufacturing method>
FIG. 9 is a flowchart illustrating a procedure for manufacturing the power storage device 10. For example, power storage device 10 is manufactured by a manufacturing apparatus.

  Referring to FIG. 9, the manufacturing apparatus places each component in container 100 (step S100). For example, the manufacturing apparatus places the power storage device element 400, to which the tab 300 with the tab film 310 is electrically connected by welding, in the space S1 in the packaging material 110, so that the storage device element 400 is placed on the flange portion 114 of the packaging material 110. The tab 300 with the tab film 310 is placed, and then the valve device 200 is placed on the flange 114 of the packaging material 110. In addition, the electricity storage device element 400 is placed in the space S1 in the packaging material 110, and then the tab 300 with the tab film 310 is welded to the electricity storage device element 400 to be electrically connected, and the flange portion of the packaging material 110 is formed. It is also possible to place the tab 300 with the tab film 310 on the 114, and then place the valve device 200 on the flange 114 of the packaging material 110. Then, the manufacturing device places the packaging material 120 on the packaging material 110.

  FIG. 10 is a diagram illustrating an operation of placing the valve device 200 between the flange portion 114 of the packaging material 110 and the packaging material 120. As shown in FIG. 10, a step is formed between the valve function part 210 and the seal attachment part 220. Therefore, when the seal mounting portion 220 is sandwiched between the packaging materials 110 and 120, even if the valve device 200 is pushed too far into the container 100, the step portion is caught by the ends of the packaging materials 110 and 120. Therefore, according to the power storage device 10, it is possible to suppress a situation in which the valve function unit 210 is erroneously sandwiched between the packaging materials 110 and 120 (the heat-fusible resin layer 35) in the manufacturing process of the power storage device 10.

  When the mounting of each component is completed, the manufacturing apparatus heat seals the periphery of the container 100 (Step S110). That is, the manufacturing apparatus applies pressure and heat to the periphery of the container 100 with the periphery of the container 100 interposed therebetween. As a result, the heat-fusible resin layers 35 facing each other are fused to each other at the peripheral edge of the container 100, and the peripheral joint portion 130 is formed. Then, the power storage device element 400 is sealed in the housing 100, the valve device 200 is fused and fixed to the peripheral joint 130, and the tab 300 is also fused to the peripheral joint 130 via the tab film 310. And the power storage device 10 is completed. In the heat sealing step, unnecessary gas is not contained in the container 100 by degassing the inside of the container 100. More specifically, the entire periphery is not joined, and a part of the unjoined edge is left, and degassing is performed from the unjoined edge. Finally, pressure and heat are applied to the unjoined edge. In addition, this completes the entire periphery joining portion 130. Further, in the case of an electricity storage device that requires an electrolytic solution, the entire periphery is not joined, and the unjoined periphery is left partially. In some cases, the electrolyte may be injected from the unjoined periphery and degassed. Finally, pressure and heat may be applied to the unjoined periphery to complete the entire peripheral joint 130.

  It is also effective that the shape of the surface of the seal bar of the manufacturing apparatus that sandwiches the periphery of the container 100 conforms to the outer shape of the seal mounting portion 220. In this case, the adhesion between the heat-fusible resin layers 35 at the position where the seal attachment portion 220 is sandwiched becomes stronger. Even in this case, in order to reduce the deformation and the load of the packaging materials 110 and 120, it is effective to make the shape of the seal attachment portion 220 flat as in Embodiment 2 described later.

<1-6. Features>
As described above, in power storage device 10 according to the first embodiment, at least a part of seal attachment portion 220 of valve device 200 is sandwiched between heat-fusible resin layers 35 at peripheral joining portion 130, and the valve device The valve function portion 210 of the second embodiment is not sandwiched between the heat-fusible resin layers 35 at the peripheral joining portion 130. Therefore, in the power storage device 10, a large pressure and heat are not applied to the valve function unit 210 as compared with the seal attachment unit 220 when the opposing heat-fusible resin layer 35 is fused. As a result, according to the power storage device 10, it is possible to suppress the failure of the valve mechanism in the valve function unit 210 due to the pressure and heat applied when the opposing heat-fusible resin layer 35 is fused.

  The power storage device element 400 is an example of the “power storage device element” of the present disclosure, the container 100 is an example of the “container” of the present disclosure, and the valve device 200 is the “valve device” of the present disclosure. This is an example. The base layer 31 is an example of a “base layer” of the present disclosure, the barrier layer 33 is an example of a “barrier layer” of the present disclosure, and the heat-fusible resin layer 35 is This is an example of the “fusible resin layer”. The peripheral joint 130 is an example of the “peripheral joint” of the present disclosure. The valve function part 210 is an example of the “first part” of the present disclosure, and the seal attaching part 220 is an example of the “second part” of the present disclosure. The air passage A1 is an example of the “air passage” of the present disclosure.

  Further, in order to easily understand that the power storage device element 400 is housed in the space S1 in the housing 100, the power storage device element 400 is shown in a small size with respect to the space S1 of the housing 100 for convenience. Although the storage device element 400 is placed in the space S1 in the manufacturing process, the space S1 is slightly larger than the power storage device element 400 in the manufacturing process, but is degassed as described above in the manufacturing process. In the state of the device 10, the space S <b> 1 is slightly reduced due to the degassing and has substantially the same size as the power storage device element 400, and the power storage device element 400 is housed in the space S <b> 1 with almost no gap.

[2. Embodiment 2]
The second embodiment differs from the first embodiment in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 11 is a plan view of valve device 200A mounted on the electric storage device according to the second embodiment. As shown in FIG. 11, the valve device 200A includes a valve function part 210A and a seal mounting part 220A. At least a part of the seal attachment portion 220A is a portion that is heat-sealed by being sandwiched between the packaging materials 110 and 120. The seal mounting portion 220A has a different cross-sectional shape as compared with the first embodiment. The valve function part 210A is basically the same as that of the first embodiment, but according to the difference in the shape of the ventilation path A6 (FIG. 12) formed in the seal attachment part 220A, the housing and the valve mechanism. The shape of has been partially changed.

  FIG. 12 is a sectional view taken along line XII-XII of FIG. As shown in FIG. 12, in the cross section of the seal attachment portion 220A, the length L5 of the power storage device in the width direction (the direction of the arrow LR) is longer than the length L6 of the power storage device in the thickness direction (the direction of the arrow UD). More specifically, the cross-sectional shape of the seal mounting portion 220A is an elliptical shape.

  An air passage A6 is formed inside the seal mounting portion 220A. Also in the ventilation path A6, the length of the power storage device in the width direction is longer than the length of the power storage device in the thickness direction. More specifically, the cross-sectional shape of the ventilation path A6 is an elliptical shape.

  As described above, in the second embodiment, in the cross section of seal mounting portion 220A, length L5 in the width direction of the power storage device is longer than length L6 in the thickness direction of the power storage device. That is, the length of the seal mounting portion 220A in the thickness direction of the power storage device is shorter than when the cross-sectional shape of the seal mounting portion is a perfect circle (the same area). In this power storage device, the length in the thickness direction of the power storage device in a portion where the seal attachment portion 220A is sandwiched in the peripheral joining portion 130, and the power storage in a portion where the seal attachment portion 220A is not sandwiched in the peripheral joining portion 130 The difference from the length in the thickness direction of the device is smaller. Therefore, according to this power storage device, pressure and heat can be appropriately applied to the heat-fusible resin layer 35 over the entire periphery of the container 100, and the opposing heat-fusible resin layers 35 are appropriately fused. Therefore, the seal mounting portion 220A of the valve device 200A can be firmly fixed to the container 100.

  The valve device 200A is an example of the “valve device” of the present disclosure, the valve function unit 210A is an example of the “first portion” of the present disclosure, and the seal mounting unit 220A is the “second device” of the present disclosure. "Part". The air passage A6 is an example of the “air passage” of the present disclosure.

[3. Third Embodiment]
Embodiment 3 differs from Embodiment 1 in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 13 is a plan view of valve device 200B mounted on the electric storage device according to the third embodiment. As shown in FIG. 13, the valve device 200B includes a valve function unit 210B and a seal mounting unit 220B. At least a part of the seal mounting portion 220B is a portion that is heat-sealed by being sandwiched between the packaging materials 110 and 120. The cross-sectional shape of the seal mounting portion 220B is different from that of the first embodiment. The valve function part 210B is basically the same as that of the first embodiment, but according to the difference in the shape of the ventilation path A7 (FIG. 14) formed in the seal attachment part 220B, the housing and the valve mechanism. The shape of has been partially changed.

  FIG. 14 is a sectional view taken along line XIV-XIV of FIG. As shown in FIG. 14, in the seal attachment portion 220B, wing-like extending ends 40 and 41 are formed at both ends in the width direction (the direction of the arrow LR) of the power storage device. Each of the wing-shaped extending ends 40 and 41 has a shape that becomes thinner as approaching the widthwise end of the power storage device. Further, from another viewpoint, each of the wing-shaped extending ends 40 and 41 has a length in the thickness direction of the power storage device in the direction of the arrow LR as compared with the other portion (circular portion) of the seal attachment portion 220B. It can be said that the change is gradual.

  In the electricity storage device according to the third embodiment, compared to the first embodiment (in a case where wing-shaped extending portions 40 and 41 are not provided in seal attaching portion 220B), seal attaching portion 220B of peripheral joining portion 130 is different from the first embodiment. The change in the thickness direction of the power storage device at the position where the portion where the seal attachment portion 220B is sandwiched between the portion where the seal is not sandwiched from the portion where the seal attachment portion 220B is sandwiched is smooth. Therefore, according to this power storage device, at the boundary between the position where the seal attaching portion 220B is sandwiched by the heat-fusible resin layer 35 and the position where the seal attaching portion 220B is not sandwiched by the heat-fusible resin layer 35. Since no excessive force is applied to the packaging materials 110 and 120, the seal mounting portion 220B of the valve device 200B can be firmly fixed to the container 100.

  The valve device 200B is an example of the “valve device” of the present disclosure, the valve function unit 210B is an example of the “first part” of the present disclosure, and the seal mounting unit 220B is the “second device” of the present disclosure. "Part". The wing-shaped extended ends 40 and 41 are examples of the “wing-shaped extended end” of the present disclosure. The air passage A7 is an example of the “air passage” of the present disclosure.

[4. Embodiment 4]
The fourth embodiment differs from the first embodiment in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 15 is a plan view of valve device 200C mounted on the electric storage device according to the fourth embodiment. As shown in FIG. 15, the valve device 200C includes a valve function unit 210C and a seal mounting unit 220C. At least a part of the seal mounting portion 220C is a portion that is heat-sealed by being sandwiched between the packaging materials 110 and 120. The seal mounting portion 220C has a different cross-sectional shape as compared with the first embodiment. The valve function part 210C is basically the same as that of the first embodiment, but according to the difference in the shape of the ventilation path A2 (FIG. 16) formed in the seal attachment part 220C, the housing and the valve mechanism. The shape of has been partially changed.

  FIG. 16 is a sectional view taken along the line XVI-XVI in FIG. As shown in FIG. 16, pillars 50 and 51 are formed in the seal attachment portion 220C (in the ventilation path A2). Each of the pillars 50 and 51 extends in the thickness direction (the direction of the arrow UD) of the power storage device, and both ends in the thickness direction of the power storage device are connected to the inner periphery of the seal attachment portion 220C. Each of the pillars 50 and 51 extends in the direction of arrow FB in the ventilation path A2 (FIG. 15). In addition, the number of pillars does not necessarily need to be two, and at least one pillar is sufficient.

  In the electricity storage device according to the fourth embodiment, since pillars 50 and 51 are formed in air passage A2, pressure and heat are applied to seal attachment portion 220C sandwiched between opposed heat-fusible resin layers 35. Even if it is performed, the ventilation path A2 is maintained. Therefore, according to this power storage device, it is possible to prevent the air passage A2 in the seal attachment portion 220C from being damaged when the opposing heat-fusible resin layer 35 is fused.

  The valve device 200C is an example of the “valve device” of the present disclosure, the valve function unit 210C is an example of the “first part” of the present disclosure, and the seal mounting unit 220C is the “second portion” of the present disclosure. "Part". The pillars 50 and 51 are examples of the “pillar” of the present disclosure. The air passage A2 is an example of the “air passage” of the present disclosure.

[5. Fifth Embodiment]
The fifth embodiment is different from the first embodiment in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 17 is a plan view of valve device 200D mounted on the electric storage device according to the fifth embodiment. As shown in FIG. 17, the valve device 200D includes a valve function part 210 and a seal mounting part 220D. The configuration of the valve function unit 210 is the same as in the first embodiment.

  At least a part of the seal mounting portion 220D is a portion which is sandwiched between the packaging materials 110 and 120 and heat-sealed. The outer surface of seal mounting portion 220D is different from that of the first embodiment. Specifically, the outer surface of the seal mounting portion 220D is a pear. The surface roughness Ra of the pear is, for example, 1 μm to 20 μm.

  In the power storage device according to the fifth embodiment, since the outer surface of seal mounting portion 220D is a pear ground, the heat-fusible resin easily melts at a position in contact with seal mounting portion 220D. Therefore, according to this power storage device, the seal mounting portion 220D of the valve device 200D can be firmly fixed to the container 100 as compared with Embodiment 1 (when the outer surface of the seal mounting portion 220D is smooth). it can.

  Note that the valve device 200D is an example of the “valve device” of the present disclosure, and the seal mounting portion 220D is an example of the “second portion” of the present disclosure.

[6. Embodiment 6]
The sixth embodiment differs from the first embodiment in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 18 is a plan view of a valve device 200E mounted on the electric storage device according to the sixth embodiment. As shown in FIG. 18, the valve device 200E includes a valve function unit 210 and a seal mounting unit 220E. The configuration of the valve function unit 210 is the same as in the first embodiment.

  At least a part of the seal attachment portion 220E is a portion which is sandwiched between the packaging materials 110 and 120 and heat-sealed. The outer surface of the seal attachment portion 220E is different from that of the first embodiment. Specifically, on the outer surface of the seal mounting portion 220E, a protruding ridge portion 60 extending continuously in the circumferential direction is formed. The three protruding ridges 60 are formed in the arrow FB direction in the seal mounting portion 220E. The number of the ridges 60 is not necessarily three, and at least one ridge 60 may be formed.

  FIG. 19 is a sectional view taken along the line XIX-XIX in FIG. As shown in FIG. 19, the cross section of the ridge 60 is semicircular. The semicircular R is, for example, 0.05 mm to 1.0 mm. The diameter L12 (the length in the thickness direction of the power storage device, the length in the width direction of the power storage device) in the portion where the ridge portion 60 is formed in the seal attachment portion 220E does not include the ridge portion 60. It is longer than the diameter L11 of the portion.

  At the time of heat sealing, the protruding ridges 60 surely come into contact with the heat-fusible resin layer 35, so that they are easily fused to the packaging materials 110 and 120. In the electricity storage device according to the sixth embodiment, ridge 60 extends continuously around the outer surface of seal mounting portion 220E in the circumferential direction. Therefore, according to this power storage device, the heat-fusible resin layer 35 and the seal attachment portion 220E can be fused together in one circumferential direction of the seal attachment portion 220E. Further, in this electric storage device, the contact between the outer surface of seal mounting portion 220E and the heat-fusible resin is different from that of the first embodiment (in the case where convex portion 60 is not formed in seal mounting portion 220E). Since the area is large, the seal mounting portion 220E of the valve device 200E can be firmly fixed to the packaging material 110.

  Note that the valve device 200E is an example of the “valve device” of the present disclosure, and the seal mounting portion 220E is an example of the “second portion” of the present disclosure. The ridge 60 is an example of the “ridge” of the present disclosure. The air passage A3 is an example of the “air passage” of the present disclosure.

  Further, in the sixth embodiment, the ridge 60 extends continuously in the circumferential direction. However, the ridge 60 may be formed on the entire circumference as long as it extends in the circumferential direction. It does not have to be continuous. For example, when the wing-shaped extending ends 40 and 41 are provided as in the above-described third embodiment, it is not necessary to provide the ridge 60 for making a full circle including the wing-shaped extending ends 40 and 41, and the wing-shaped extending end is not required. It is also possible to provide no ridge 60 at the tip of the ends 40, 41, or to provide no ridge 60 in the wing-like extending ends 40, 41, and to extend the ridge 60 in the circumferential direction. It is also possible to form it intermittently.

[7. Embodiment 7]
The seventh embodiment is different from the first embodiment in the configuration of the valve device. Other configurations are basically the same as those of the first embodiment. Here, portions different from the first embodiment will be described.

  FIG. 20 is a plan view of valve device 200F mounted on the electric storage device according to the seventh embodiment. As shown in FIG. 20, the valve device 200F includes a valve function unit 210F and a seal mounting unit 220F. At least a part of the seal mounting portion 220F is a portion that is heat-sealed by being sandwiched between the packaging materials 110 and 120. The valve function part 210F and the seal attachment part 220F have different cross-sectional shapes as compared with the first embodiment.

  FIG. 21 is a sectional view taken along the line XXI-XXI of FIG. As shown in FIG. 21, the cross section of the valve function unit 210F has a semicircular shape. That is, the surface of the valve function unit 210F in the direction of the arrow U is flat. The cross section of the seal mounting portion 220F has wing-like extending ends 40F and 41F at both ends in the direction of the arrow LR. The surface of the seal mounting portion 220F in the direction of arrow U is flat. The surface of the valve function portion 210F in the direction of the arrow U and the surface of the seal mounting portion 220F in the direction of the arrow U are flush with each other.

  Therefore, when the valve device 200F is disposed with the surface in the direction of the arrow U facing down, the valve device 200F does not roll. Therefore, according to the electric storage device according to the seventh embodiment, when mounting valve device 200F to container 100, valve device 200F does not roll, so that valve device 200F can be easily positioned.

  FIG. 22 is a diagram illustrating a state in which the valve device 200F is attached to the container 100. As shown in FIG. 22, when the valve device 200F is attached to the container 100, the plane of the valve device 200F is placed on the surface of the innermost layer of the packaging material 120. In this state, the valve device 200F does not roll. Therefore, according to the electric storage device according to the seventh embodiment, when mounting valve device 200F to container 100, positioning of valve device 200F can be easily performed. In addition, in the state of the power storage device, the bulging of the peripheral joint 130 by the valve device 200F can be directed in the direction in which the container 100 swells, that is, in FIG.

  The valve device 200F is an example of the “valve device” of the present disclosure, the valve function unit 210F is an example of the “first part” of the present disclosure, and the seal mounting unit 220F is the “second device” of the present disclosure. "Part". The air passage A4 is an example of the “air passage” of the present disclosure.

[8. Modification]
Although the first to seventh embodiments have been described above, the present disclosure is not limited to the first to seventh embodiments, and various changes can be made without departing from the gist of the present disclosure. Hereinafter, modified examples will be described. However, the following modifications can be combined as appropriate.

<8-1>
In the first to seventh embodiments, the cross section of the seal mounting portion (the seal mounting portion 220 and the like) has a shape based on a circle. However, the cross-sectional shape of the seal mounting portion is not limited to this. For example, the cross-sectional shape of the seal mounting portion may have a shape based on a polygon.

  FIG. 23 is a diagram illustrating a cross section of the valve device 200G according to the first modification. As shown in FIG. 23, in the valve device 200G, the cross section of the seal mounting portion 220G has a rhombic shape. In seal mounting portion 220G, length L7 in the width direction of the power storage device is longer than length L8 in the thickness direction of the power storage device. In this power storage device, the length in the thickness direction of the power storage device in the portion where the seal attachment portion 220G is sandwiched in the peripheral joining portion 130 and the power storage in the portion where the seal attachment portion 220G is not sandwiched in the peripheral joint portion 130 The difference from the length in the thickness direction of the device is smaller. Therefore, according to this power storage device, pressure and heat can be appropriately applied to the heat-fusible resin layer 35 over the entire periphery of the container 100, and the opposing heat-fusible resin layers 35 are appropriately fused. Therefore, the seal mounting portion 220G of the valve device 200G can be firmly fixed to the container 100.

  FIG. 24 is a diagram illustrating a cross section of the valve device 200H according to the second modification. As shown in FIG. 24, in the valve device 200H, the cross section of the seal attachment portion 220H has a rhombic shape or a hexagonal shape chamfered at both ends in the thickness direction of the power storage device. In seal mounting portion 220H, length L9 in the width direction of the power storage device is longer than length L10 in the thickness direction of the power storage device. In this power storage device, the length in the thickness direction of the power storage device in the portion where the seal attachment portion 220H is sandwiched in the peripheral joining portion 130 and the power storage in the portion where the seal attachment portion 220H is not sandwiched in the peripheral joining portion 130 The difference from the length in the thickness direction of the device is smaller. Therefore, according to this power storage device, pressure and heat can be appropriately applied to the heat-fusible resin layer 35 over the entire periphery of the container 100, and the opposing heat-fusible resin layers 35 are appropriately fused. Therefore, the seal mounting portion 220H of the valve device 200H can be firmly fixed to the container 100.

  FIG. 25 is a diagram illustrating a cross section of the valve device 200I according to the third modification. As shown in FIG. 25, in the valve device 200I, the cross section of the seal mounting portion 220I has a shape in which wing-shaped extending ends 40I and 41I are provided at both ends of the rhombus (in the width direction of the power storage device). I have. In this electricity storage device, for example, as compared with Embodiment 1 (when the wing-shaped extending ends 40I and 41I are not provided in the seal attachment portion 220I), the seal attachment portion 220I of the peripheral joining portion 130 is sandwiched. The change in the thickness direction of the power storage device at the position where the transition from the non-existing portion to the portion where the seal attachment portion 220I is sandwiched of the peripheral joining portion 130 is smooth. Therefore, according to this power storage device, at the boundary between the position where the seal attaching portion 220I is sandwiched by the heat-fusible resin layer 35 and the position where the seal attaching portion 220I is not sandwiched by the heat-fusible resin layer 35. Since no excessive force is applied to the packaging materials 110 and 120, the seal mounting portion 220I of the valve device 200I can be firmly fixed to the container 100.

  FIG. 26 is a plan view of a valve device 200J according to the fourth modification. As shown in FIG. 26, the valve device 200J includes a valve function part 210J and a seal mounting part 220J. An air passage A5 is formed in the seal attachment portion 220J.

  FIG. 27 is a sectional view taken along the line XXVII-XXVII of FIG. This cross section can also be said to be a plane having the center line C1 of the ventilation path A5 as a normal line. As shown in FIG. 27, in the valve device 200J, the cross section of the seal mounting portion 220J has a hexagonal (polygonal) shape. R (for example, R = 0.2 mm to 2.0 mm) is formed at each corner of the hexagon. According to this power storage device, for example, the possibility that a portion of seal mounting portion 220 </ b> J located within housing 100 can damage power storage device element 400 within housing 100 can be reduced, and seal mounting portion 220 </ b> J can be reduced. Of these, the portion sandwiched between the heat-fusible resin layers 35 can damage the heat-fusible resin layers 35 and reduce the possibility of lowering the insulating properties of the heat-fusible resin layers 35.

<8-2>
In the first to seventh embodiments, the flange portion 114 of the packaging material 110 is in a flat state. However, the shape of the flange 114 is not limited to this. For example, a valve device arranging portion for arranging the seal mounting portion 220 of the valve device 200 may be formed in the flange portion 114 in advance.

  FIG. 28 is a plan view of a packaging material 110K according to the fifth modification. As shown in FIG. 28, a valve device arrangement portion 116K is formed in the flange portion 114K.

  FIG. 29 is a sectional view taken along the line XXIX-XXIX of FIG. As shown in FIG. 29, the valve device arrangement portion 116K formed on the flange portion 114K has a semicircular shape. The diameter of this semicircle is, for example, slightly longer than the diameter of the seal mounting part 220. In a state where, for example, the seal mounting portion 220 is arranged in the valve device arrangement portion 116K, heat sealing is performed on the periphery of the container. Thereby, the deformation of the packaging material at the time of heat sealing is suppressed, and the possibility that pinholes or tears occur near the seal attachment portion 220 can be reduced. In addition, the valve device arrangement part 116K does not necessarily need to be provided in the packaging material 110K, and may be provided in the packaging material 120. Even in this case, the same effect as when the valve device arrangement portion 116K is provided on the packaging material 110K can be obtained.

<8-3>
In the first to seventh embodiments, only a part of the seal attachment portion (for example, the seal attachment portion 220) is sandwiched between the heat-fusible resin layers 35 at the peripheral joining portion 130. However, the mounting state of the seal mounting portion is not limited to this. For example, the entirety of the seal attaching portion may be sandwiched between the heat-fusible resin layers 35 at the peripheral joining portion 130. Even in such a case, R is formed at the corner in plan view of the end of the seal mounting portion (for example, the seal mounting portion 220) opposite to the valve function portion (for example, the valve function portion 210). Therefore, it is unlikely that the ends damage the heat-fusible resin layer 35 and lower the insulating properties of the heat-fusible resin layer 35.

<8-4>
In the first to seventh embodiments, in the valve device (for example, valve device 200), a step is formed at the boundary between the valve function unit (for example, valve function unit 210) and the seal attachment unit (for example, seal attachment unit 220). Had been formed. However, a step is not necessarily formed at the boundary between the valve function part and the seal attachment part. For example, the cross-sectional diameter of the valve function part and the cross-sectional diameter of the seal mounting part may be the same, and the valve function part and the seal mounting part may be connected flat.

<8-5>
In the first to seventh embodiments, the cross section of the air passage (for example, the air passage A1) formed in the seal attachment portion (such as the seal attachment portion 220) has a circular base shape. However, the cross-sectional shape of the ventilation path is not limited to this. For example, the cross-sectional shape of the ventilation path may be a shape based on a polygon.

<8-6>
In Embodiments 1 to 7, R is formed at the corner of the end of the seal mounting portion (for example, the seal mounting portion 220) opposite to the valve function portion (for example, the valve function portion 210). However, the corner does not necessarily have to be formed with R.

<8-7>
In the first to seventh embodiments, the valve device (for example, the valve device 200) is a so-called return valve. However, the valve device need not necessarily be a return valve. The valve device may be, for example, a so-called break valve or a selective permeation valve.

<8-8>
Referring again to FIG. 1, in the first to seventh embodiments, tabs 300 are provided at both ends in the direction of arrow LR of container 100, and a valve device (for example, valve device 200) is provided with an arrow of container 100. It was provided at the end in the F direction. However, the positional relationship between the valve device 200 and the tab 300 is not limited to this. For example, both tabs 300 may be disposed on the same side of the periphery of the container 100, the valve device may be disposed between the two tabs 300, or both tabs 300 may be the same on the periphery of the container 100. The valve device may be disposed on any one of the three sides other than the side on which the tab 300 is disposed on the side.

<8-9>
In the first to seventh embodiments, the container 100 includes the packaging material 110 formed by embossing or the like, and the packaging material 120 separate from the packaging material 110. However, the container 100 does not necessarily have to have such a configuration.

  For example, the packaging material 110 and the packaging material 120 may be integrated (connected) in advance on one side. In this case, at the end of the flange portion 114 of the packaging material 110, the packaging material 110 and the packaging material 120 are integrated (connected), and the packaging material 110 and the packaging material 120 are stacked. The power storage device element 400 may be sealed in the housing 100 by performing four-side sealing. Further, the flange portion 114 is omitted on the side where the packaging material 110 and the packaging material 120 are integrated, and the packaging material 110 and the packaging material 120 are sealed in a three-way manner in a stacked state, so that the container 100 The power storage device element 400 may be sealed therein.

  Further, for example, the packaging material 120 may be formed in the same shape as the packaging material 110. The container 100 may be, for example, a pouch-type container. The pouch type container may be any type such as a three-side seal type, a four-side seal type, a pillow type, and a gusset type.

<8-10>
In Embodiments 1 to 7, the housing of the valve function unit (for example, the valve function unit 210) and the housing of the seal mounting unit (for example, the seal mounting unit 220) are formed of the same material (resin). Was. However, the casing of the valve function section and the casing of the seal mounting section need not necessarily be formed of the same material. For example, the housing of the valve function part and the housing of the seal attachment part may be made of different materials, and the melting point of the material of the valve function part may be higher than the melting point of the material of the seal attachment part. For example, the seal attachment portion is made of polypropylene (PP), and the valve function portion is made of a resin having a melting point higher than PP (for example, a fluorine resin, a polyester resin, a polyimide resin, a polycarbonate resin, an acrylic resin) or a metal. May be done. As a resin used for the seal mounting portion, a fluororesin having a high barrier is preferable.

  In this electricity storage device, even when pressure and heat are applied to the seal attachment portion during fusion of the opposing heat-fusible resin layer 35, the melting point of the material of the valve function portion is higher than the melting point of the material of the seal attachment portion. Since it is high, the possibility that the valve function section is deformed by heat is low. Therefore, according to this power storage device, it is possible to suppress failure of the valve mechanism in the valve function unit when the opposing heat-fusible resin layer 35 is fused.

<8-11>
In the first to seventh embodiments, the casing of the valve device 200 is made of resin, and the seal attachment portion 220 is directly sandwiched between the heat-fusible resin layers 35. However, the housing of the valve device 200 does not necessarily need to be made of resin, and may be made of, for example, metal (for example, aluminum or stainless steel). In this case, an adhesive protection film may be disposed between the seal attachment portion 220 and the heat-fusible resin layer 35. The adhesive protective film is configured so that one surface is bonded to at least resin, and the other surface is configured to be bonded to at least metal. As the adhesive protective film, various known adhesive protective films can be employed. For example, the same adhesive protective film as the tab film 310 can be used.

<8-12>
In the first to seventh embodiments, the outer peripheral side of the seal attaching portion (for example, the seal attaching portion 220) (the corner of the end opposite to the valve function portion (for example, the valve function portion 210) side of the seal attaching portion). Was formed, but no R was formed on the inner peripheral side of the seal mounting portion (the edge of the ventilation path (for example, the ventilation path A1)). However, R may be formed on the inner peripheral side of the seal attachment portion. By forming the R on the inner peripheral side of the seal attaching portion, the possibility that the corner on the inner peripheral side of the seal attaching portion is cut and dust (eg, resin, metal, etc.) falls into the container 100 is reduced. be able to.

<8-13>
Referring to FIG. 21 again, in the seventh embodiment, a flat surface is formed on both outer surfaces of valve function section 210F and seal mounting section 220F. However, it is not always necessary to form a flat surface on both outer surfaces of the valve function part 210F and the seal attachment part 220F. It suffices that a flat surface is formed on at least one outer surface of the valve function part 210F and the seal attachment part 220F.

<8-14>
The power storage device 10 according to the first to seventh embodiments is a secondary battery, but is defined by the concept of outputting electricity. For example, a capacitor, an electric double layer capacitor (EDLC), It also includes an electricity storage device such as a lithium ion capacitor, and the type of the secondary battery is not particularly limited. For example, a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel hydrogen battery, a nickel cadmium battery Examples include batteries, nickel-iron storage devices, nickel-zinc storage batteries, silver oxide-zinc storage batteries, metal-air batteries, polyvalent cation batteries, and all-solid batteries.

  Hereinafter, the present disclosure will be described in detail with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the embodiments.

[Example 1-11]
<Preparation of packaging material>
A barrier layer made of an aluminum foil (JIS H4160: 1994 A8021H-O, thickness 40 μm, crystal grain size 4.2 μm) having an acid-resistant film formed on both sides on a polyethylene terephthalate film (25 μm) as a substrate layer. Lamination was performed by a dry lamination method. Specifically, a two-component curable urethane adhesive (with a polyol compound) is formed on one side of an aluminum foil having an acid-resistant film (a film formed by chromate treatment and having a chromium content of 10 mg / m ² ) formed on both surfaces. An aliphatic isocyanate compound) was applied, and an adhesive layer (thickness after curing was 3 μm) was formed on the aluminum foil. Next, after laminating the adhesive layer on the aluminum foil and the polyethylene terephthalate film, an aging treatment was performed to produce a laminate of the base material layer / adhesive layer / barrier layer. Next, a maleic anhydride-modified polypropylene (thickness: 30 μm) as an adhesive layer and a polypropylene (thickness: 30 μm) as a heat-fusible resin layer are coextruded on the barrier layer of the obtained laminate. Thereby, the adhesive layer / heat-fusible resin layer was laminated on the barrier layer. Next, after the obtained laminate is once cooled, it is subjected to a heat treatment to provide a base layer (25 μm) / adhesive layer (3 μm) / barrier layer (30 μm) / heat-fusible resin layer (60 μm) in this order. A laminated packaging material was obtained. The tensile breaking strength of each packaging material was 123 N / 15 mm for MD and 169 N / 15 mm for TD. The tensile breaking strength in MD and TD of each packaging material was measured using a tensile tester (AG-Xplus, manufactured by Shimadzu Corporation) according to a method based on JIS K7127. The measurement conditions were a rectangular shape with a sample width of 15 mm, a distance between marked lines of 30 mm, a tensile speed of 100 mm / min, a test environment of 23 ° C., and an average value measured three times.

<Preparation of test sample>
The obtained packaging material was cut into strips having a length of 130 mm and a width of 120 mm. One strip was subjected to cold forming such that the heat-fusible resin layer side became a concave portion to form a formed portion having a length of 110 mm, a width of 100 mm and a depth of 5 mm. Next, the heat-fusible resin layer side of another strip piece was overlapped from above the molded portion, and the heat-fusible resin layers facing each other at the peripheral edge were thermally fused to seal the molded portion. . At this time, as shown in FIG. 1, two sets of the tab 300 and the tab film 310 and the valve device 200 are interposed between the heat-fusible resin layers facing each other on the peripheral edge, and the heat-sealing resin layers are interposed. By doing so, a peripheral edge joint was formed. The tab of the positive electrode is an aluminum foil, and the tab of the negative electrode is a CuNi-plated tab, each having a thickness of 0.1 mm, a length of 30 mm, and a width of 30 mm, and subjected to the same chromate treatment as the barrier layer. The tab film is a maleic anhydride-modified polypropylene film (100 μm in thickness).

  The conditions of the heat fusion were adjusted in each example such that the surface pressure was adjusted between 0.1 MPa and 1.0 MPa, the temperature was 190 ° C., the sealing time was 30 seconds, and the sealing width was 7 mm. By changing the conditions of the heat-fusible resin layer, the thickness ratio of the heat-fusible resin layer, X, Y ( %) Changes. As described above, the thickness ratio X of the heat-fusible resin layer is determined by determining the thickness of one of the portions where the opposing heat-fusible resin layers are fusion-bonded to each other at the peripheral joining portion of the packaging material. It is a ratio (%) of the thickness of the adhesive resin layer. The thickness ratio Y (%) of the heat-fusible resin layer is the ratio (%) of the thickness of the heat-fusible resin layer at a position sandwiching the valve device. The criterion of the ratios X and Y (%) of the thickness of the heat-fusible resin layer is the thickness of the heat-fusible resin layer (100%, ie, 60 μm). Table 1 shows the ratios X and Y of the thickness of the heat-fusible resin layer in Example 1-11. Note that the thickness ratios X and Y of the heat-fusible resin layer are values calculated by measuring the thickness of the cross-section of the heat-fusible resin layer, respectively.

  A notch (200 μm) is provided at a position where the tab 300 is located as a seal bar used for heat fusion of a peripheral edge where the tab 300 is located, so that a heat-fusible resin located on the tab 300 is located. The layer is suppressed from being significantly crushed. Similarly, as a seal bar used for heat fusion of the periphery where the valve device 200 is located, the shape of the location where the seal mounting portion 220 of the valve device 200 is located is processed so as to conform to the shape of the seal mounting portion 220. As a result, the heat-fusible resin layer located on the seal attachment portion 220 is suppressed from being significantly crushed, and the thickness of the heat-fusible resin layer after heat-sealing (particularly the heat-fusible resin layer The thickness ratio Y (%)) is adjusted.

  The valve device 200 has the size and appearance as shown in FIG. 30, and the valve mechanism is a ball spring type, and the operating pressure is adjusted by a spring (spring). The seal mounting portion 220 (length 5.0 mm, outer diameter φ of the curved surface portion 220 a φ5.0 mm, inner diameter φ of the vent hole 3.0 mm) and the valve function portion 210 (length 13.0 mm, outer diameter φ6.0 mm) are polypropylene. It was made of resin.

  The obtained test sample is set so that the valve device is opened when the differential pressure (opening pressure) between the primary side and the secondary side of the valve device is in the range of 0.05 MPa or more and 0.3 MPa or less. Specifically, the differential pressure (opening pressure) between the primary side and the secondary side of the valve device was set to 0.1 MPa. As in this test sample, when the electricity storage device includes at least a container constituted by a laminate having a base layer, a barrier layer, and a heat-fusible resin layer in this order, a valve device is provided separately from the container. And the differential pressure between the primary side and the secondary side of the valve device is set so that the valve device is opened within a range of 0.05 MPa or more and 0.3 MPa or less. When the gas was generated inside while maintaining the high sealing property of the electricity storage device in the use state of, the gas could be preferably discharged to the outside.

  Next, the release of gas to the outside was evaluated under severe conditions of open tests 1 and 2.

<Opening test 1: Opening from valve device>
At the time of producing the test sample of Example 1-11, another valve device (provided that the valve function was removed and the air passage was provided) on the side (the B side in FIG. 1) opposite to the side on which the valve device was attached. A test sample for the open test 1 was prepared in the same manner as in each example except that the test sample was attached. The obtained test sample was inserted into a frame to which a stainless steel plate (thickness: 5 mm) was fixed at intervals of 7 mm. Next, the internal pressure was increased by injecting air from a valve device serving as an air passage, and the state and pressure at the time of opening were confirmed. This test was performed for each of five test samples (n = 5), and evaluated according to the following criteria. Table 1 shows the results.
A: For all test samples, the valve device was opened and gas was released to the outside, and there was no change in the portion where the heat-fusible resin layers were heat-sealed.
B: With respect to all the test samples, the valve device was opened and the gas was released to the outside, but there was a sample in which the portion where the heat-fusible resin layers were heat-sealed receded (peeled).
C: There was a test sample in which gas was released by cleavage of a portion different from the valve device.

<Opening test 2: Opening when a failure occurs in the valve device>
At the time of manufacturing the test sample of Example 1-11, another valve was placed on the side (the B side in FIG. 1) opposite to the side on which the valve device (with the valve function removed and sealed) was attached. A test sample for the open test 2 was prepared in the same manner as in each example, except that a device (however, the valve function was removed and the valve device was used as an air passage) was attached. The obtained test sample was inserted into a frame to which a stainless steel plate (thickness: 5 mm) was fixed at intervals of 7 mm. Next, the internal pressure was increased by injecting air from a valve device serving as an air passage, and the state and pressure at the time of opening were confirmed. This test was performed for each of five test samples (n = 5), and evaluated according to the following criteria. Table 1 shows the results.
A: With respect to all the test samples, the space between the mounting portion of the valve device and the heat-fusible resin layer was cleaved and gas was released to the outside, and the portion where the heat-fusible resin layers were fused also changed. Did not.
B: In all the test samples, the gas was released to the outside while the space between the mounting portion of the valve device and the heat-fusible resin layer was opened, but the portion where the heat-fusible resin layers were fused receded. (Peeling) was present.
C: There was a test sample which was cleaved from a portion different from the portion between the mounting portion of the valve device and the heat-fusible resin layer to release gas.

<Leak test>
In producing the test sample of Example 1-11, Example 1-11 was repeated except that 50 g of a test solution obtained by mixing 5% of permeate (NEW Microcheck Model No. 00143 Itinene Chemicals) with an electrolyte was sealed in the molded part. Each test sample was prepared in the same manner as described above. The electrolyte was a 1 × 10 ³ mol / m ³ LiPF ₆ solution (ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (DEC) = 1/1/1 volume ratio). Next, each of the obtained test samples was dropped 20 times from a height of 1.5 m, and then the leakage of the test solution from each test sample was visually confirmed. The case where there was no leakage was evaluated as A, and the case where there was leakage was evaluated as C. Table 1 shows the results.

<Insulation test>
The packaging material was cut into strips 60 mm long × 60 mm wide. Next, the strip is folded in two in the length direction, and the opposing two sides are heat-sealed with a width of 7 mm so that the terminal extends outside from one side, and a pouch type having an opening on one side. A container was prepared. Next, a dummy cell made of an acrylic resin plate was sealed in the obtained container, an electrolytic solution was put therein, and the opening was hermetically sealed with a width of 3 mm to produce a test sample. At this time, the heat sealing was performed under the same sealing conditions as in Example 1-11 (thus, the thickness of the heat-fusible resin layer in the heat-sealed portion was the same as the thickness X described above). Next, the portion of the obtained test sample that had been heat-sealed after sealing the electrolyte was bent inward and returned. Next, an insulation evaluation test for cracks was performed using an impulse application method (a lithium-ion battery insulation tester manufactured by Japan Technate Co., Ltd.). First, 10 test samples were prepared, and an impulse voltage of 100 V was applied between the terminal of each test sample and the aluminum foil of the packaging material. The voltage drop after 99 msec was within 40 V. Was passed. The criteria for the three-step evaluation were set as follows based on the number of NGs (fail, voltage drop of 40 V or more). Table 1 shows the evaluation results.
Number of NG in 10 samples A: Number of NG 0 B: Number of NG 1 to 4 C: Number of NG 5 or more

<Measurement of peel strength X, Y>
For each of the test samples prepared in Example 1-11, the peel strength X between the heat-fusible resin layers at the portion where the heat-fusible resin layers facing each other are located at the peripheral joining portion and are fused to each other. The peel strength Y between the heat-fusible resin layer and the valve device at the position sandwiching the valve device was measured by the following procedure. Peel strengths X and Y were measured in a 25 ° C. environment in accordance with JIS K7127: 1999. First, for the measurement of the peel strength X, a test piece was obtained by cutting the heat-fusible resin layer of each test sample so that the width became 15 mm from the heat-sealed portion. In the measurement of the peel strength Y, in a state where the valve device of each test sample and the heat-fusible resin layer were fused, the heat-fusible resin layer was cut so as to have a width of 5 mm, and the test piece was cut. I got Next, each test piece was peeled off the heat-fusible resin layer by 4 mm at a speed of 300 mm / min using a tensile tester (AG-Xplus, manufactured by Shimadzu Corporation). The maximum strength at the time of peeling was defined as peel strength (N / 15 mm). Since the peel strength Y was measured at a width of 5 mm, a value obtained by triple the actually measured value was taken as the peel strength Y (N / 15 mm). The distance between the chucks is 50 mm, and the peeling angle is 180 degrees. Each was an average value measured three times. Table 1 shows the results.

  As shown in Table 1, particularly in Examples 1 to 6, the ratio X of the thickness of the heat-fusible resin layer is in the range of 50 to 80%, and the ratio Y of the thickness of the heat-fusible resin layer is about It is in the range of 60 to 90%, and the degree to which the heat-fusible resin layer is crushed by heat and pressure during sealing is appropriately adjusted by adjusting the sealing conditions when the heat-fusible resin layer is heat-sealed. I have. Also, the peel strengths X and Y are adjusted in the same manner. Since the peel strength X is larger than the peel strength Y, in the open test 2, the distance between the mounting portion of the valve device and the heat-fusible resin layer is increased. It can be seen from FIG. 3 that the gas is properly released to the outside. In Examples 1 to 6, in the severe evaluations of the open tests 1 and 2, the leak test, and the insulation test, there was no evaluation C, and it can be seen that the storage device was particularly excellent.

As described above, the present disclosure provides the following aspects of the invention.
Item 1. A power storage device element,
At least, a base body, a barrier layer and a heat-fusible resin layer are configured by a laminate having in this order, a housing body for housing the electricity storage device element therein,
A valve device communicating with the inside of the container,
At the periphery of the container, the heat-fusible resin layer faces,
On the peripheral edge of the container, a peripheral joint portion where the opposed heat-fusible resin layers are fused to each other is formed,
At least a portion of the valve device is sandwiched between the heat-fusible resin layers facing each other at the peripheral joint portion, so that the valve device is attached to the container,
The power storage device, wherein the valve device is set such that the valve device is opened when a differential pressure between a primary side and a secondary side of the valve device is in a range of 0.05 MPa or more and 0.3 MPa or less.
Item 2. Item 2. The power storage device according to Item 1, wherein the thickness of the heat-fusible resin layer is 50 μm or more and 100 μm or less.
Item 3. In the container, when the thickness of the heat-fusible resin layer which is located at the center of the container and is not fused to each other is set to 100%, the heat-fusible resin layer which is located at the peripheral joining portion and faces the thermal fusion Item 3. The electric storage device according to Item 1 or 2, wherein the ratio X of the thickness of one of the heat-fusible resin layers in a portion where the adhesive resin layers are fused to each other is in a range of 50% or more and 80% or less. .
Item 4. In the container, when the thickness of the heat-fusible resin layer that is located at the center of the container and is not fused to each other is 100%, the heat fusion at a position sandwiching the valve device is performed. Item 4. The power storage device according to any one of Items 1 to 3, wherein a ratio Y of the thickness of the conductive resin layer is in a range of 60% or more and 90% or less.
Item 5. In the container, the thickness ratio Y of the heat-fusible resin layer at a position sandwiching the valve device is located at the peripheral edge joint, and the opposing heat-fusible resin layers are fused to each other. The power storage device according to any one of Items 1 to 4, wherein the ratio of the thickness of the heat-fusible resin layer of one of the portions is larger than X.
Item 6. The container has a rectangular shape in plan view,
The power storage device according to any one of claims 1 to 5, wherein the valve device is located at a position different from a side of the housing where the tab is located.
Item 7. The valve device includes:
A valve mechanism for reducing the pressure when the pressure inside the container increases due to gas generated inside the container,
An air passage for guiding gas generated inside the container to the valve mechanism,
The electricity storage device according to any one of claims 1 to 6, wherein the ventilation path includes a membrane that transmits gas and suppresses transmission of liquid.
Item 8. Item 8. The electricity storage device according to any one of Items 1 to 7, wherein the membrane is a polytetrafluoroethylene membrane.
Item 9. In the container, the peel strength X between the heat-fusible resin layers in a portion where the heat-fusible resin layers opposed to each other are located at the peripheral joining portion and are fused to each other sandwiches the valve device. The electric storage device according to any one of Items 1 to 7, wherein the peel strength between the heat-fusible resin layer and the valve device at a position where the heat-fusible resin layer is located is larger than the peel strength Y.
Item 10. The valve device includes:
A first portion formed therein with a valve mechanism that reduces the pressure when the pressure inside the container increases due to gas generated inside the container;
A second portion having an air passage formed therein for guiding a gas generated inside the container to the valve mechanism,
The first portion is located outside an edge of the peripheral joint,
Item 10. The power storage device according to any one of Items 1 to 9, wherein at least a part of the second portion is sandwiched between the heat-fusible resin layers at the peripheral joining portion.
Item 11. In the thickness direction of the power storage device, the length of the first portion is longer than the length of the second portion,
Item 11. The power storage device according to Item 10, wherein a step is formed at a boundary between the first portion and the second portion.
Item 12. The power storage device according to claim 10 or 11, wherein a length of the second portion in a width direction of the power storage device is longer than a length of the second portion in a thickness direction of the power storage device.
Item 13. The power storage device according to any one of Items 10 to 12, wherein the second portion has a wing-shaped extending end portion that is formed thinner as approaching an end portion in the width direction of the power storage device.
Item 14. 14. The power storage device according to any one of Items 10 to 13, wherein a cross-sectional shape of the ventilation path is circular.
Item 15. The power storage device according to any one of claims 10 to 14, wherein a cross-sectional length of the ventilation path in a width direction of the power storage device is longer than a cross-sectional length of the ventilation path in a thickness direction of the power storage device. .
Item 16. The power storage device according to any one of Items 10 to 15, wherein the second portion has a pillar formed in the ventilation path.
Item 17. The power storage device according to any one of Items 10 to 16, wherein an outer surface of the second portion is a pear ground.
Item 18. The power storage device according to any one of Items 10 to 17, wherein at least one ridge extending in a circumferential direction is formed on an outer surface of the second portion.
Item 19. The power storage device according to any one of Items 10 to 18, wherein, in the second portion, an end of the end opposite to the first portion has a rounded corner in plan view.
Item 20. The outer shape of the cross section of the second portion having the center line of the ventilation path as a normal line is a polygon,
Item 20. The power storage device according to any one of Items 10 to 19, wherein corners of the polygon are rounded.
Item 21. Each of the first portion and the second portion is made of a different material,
21. The electricity storage device according to any one of items 10 to 20, wherein a melting point of the material of the first portion is higher than a melting point of the material of the second portion.
Item 22. 22. The power storage device according to any one of Items 10 to 21, wherein a plane is formed on at least a part of an outer surface of at least one of the first portion and the second portion.

  Reference Signs List 10 electricity storage device, 31 base material layer, 32 adhesive layer, 33 barrier layer, 33a crystal grain, 34 adhesive layer, 35 heat-fusible resin layer, 40, 40I, 41, 41I winged end portion, 50, 51 pillar , 60 ridges, 100 container, 110, 110K, 120 packaging material, 112 molding, 114, 114K flange, 116K valve device arrangement, 130 peripheral joint, 200, 200A, 200B, 200C, 200D, 200E , 200F, 200G, 200H, 200I, 200J Valve device, 210, 210A, 210B, 210C, 210E, 210F, 210G, 210H, 210I, 210J Valve function part, 212 valve seat, 214 ball, 216 spring, 218 membrane, 220 , 220A, 220B, 220C, 220D, 220E, 20F, 220G, 220H, 220I, 220J seal mounting portion, 300 tabs 310 tabs film, 400 electric storage device element, A1, A2, A3, A4, A5, A6, A7 air passage, C1 centerline, O1 outlet.

Claims (22)

A power storage device element,
At least, a base body, a barrier layer and a heat-fusible resin layer are configured by a laminate having in this order, a housing body for housing the electricity storage device element therein,
A valve device communicating with the inside of the container,
At the periphery of the container, the heat-fusible resin layer faces,
On the peripheral edge of the container, a peripheral joint portion where the opposed heat-fusible resin layers are fused to each other is formed,
At least a portion of the valve device is sandwiched between the heat-fusible resin layers facing each other at the peripheral joint portion, so that the valve device is attached to the container,
The power storage device, wherein the valve device is set such that the valve device is opened when a differential pressure between a primary side and a secondary side of the valve device is in a range of 0.05 MPa or more and 0.3 MPa or less.   The power storage device according to claim 1, wherein the thickness of the heat-fusible resin layer is 50 μm or more and 100 μm or less.   In the container, when the thickness of the heat-fusible resin layer that is located at the center of the container and is not fused to each other is set to 100%, the heat-fusible resin layer that is located at the peripheral joining portion and faces the heat-fusible resin layer facing each other. 3. The method according to claim 1, wherein a ratio X of a thickness of one of the heat-fusible resin layers in a portion where the adhesive resin layers are fused to each other is in a range of 50% or more and 80% or less. 4. Power storage device.   In the container, when the thickness of the heat-fusible resin layer that is located at the center of the container and is not fused to each other is 100%, the heat fusion at a position sandwiching the valve device is performed. The power storage device according to any one of claims 1 to 3, wherein a ratio Y of the thickness of the conductive resin layer is in a range of 60% or more and 90% or less.   In the container, the thickness ratio Y of the heat-fusible resin layer at a position sandwiching the valve device is located at the peripheral edge joint, and the opposing heat-fusible resin layers are fused to each other. The power storage device according to any one of claims 1 to 4, wherein a ratio of the thickness X of the heat-fusible resin layer of one of the portions is larger than X. The container has a rectangular shape in plan view,
The power storage device according to any one of claims 1 to 5, wherein the valve device is located at a position different from a side of the housing where the tab is located. The valve device includes:
A valve mechanism for reducing the pressure when the pressure inside the container increases due to gas generated inside the container,
An air passage for guiding gas generated inside the container to the valve mechanism,
The power storage device according to any one of claims 1 to 6, wherein the ventilation path includes a membrane that transmits gas and suppresses transmission of liquid.   The electricity storage device according to any one of claims 1 to 7, wherein the membrane is a polytetrafluoroethylene membrane.   In the container, the peel strength X between the heat-fusible resin layers in a portion where the heat-fusible resin layers opposed to each other are located at the peripheral joining portion and are fused to each other sandwiches the valve device. The power storage device according to any one of claims 1 to 7, wherein the peel strength between the heat-fusible resin layer and the valve device at a position where the heat-fusible resin layer is located is higher than the peel strength Y. The valve device includes:
A first portion formed therein with a valve mechanism that reduces the pressure when the pressure inside the container increases due to gas generated inside the container;
A second portion having an air passage formed therein for guiding a gas generated inside the container to the valve mechanism,
The first portion is located outside an edge of the peripheral joint,
The power storage device according to any one of claims 1 to 9, wherein at least a part of the second portion is sandwiched between the heat-fusible resin layers at the peripheral edge joint. In the thickness direction of the power storage device, the length of the first portion is longer than the length of the second portion,
The power storage device according to claim 10, wherein a step is formed at a boundary between the first portion and the second portion.   The power storage device according to claim 10, wherein a length of the second portion in a width direction of the power storage device is longer than a length of the second portion in a thickness direction of the power storage device.   The power storage device according to any one of claims 10 to 12, wherein the second portion has a wing-shaped extending end portion that is formed thinner toward an end portion in a width direction of the power storage device.   The power storage device according to any one of claims 10 to 13, wherein a cross-sectional shape of the ventilation path is circular.   15. The power storage device according to claim 10, wherein a cross-sectional length of the air passage in a width direction of the power storage device is longer than a cross-sectional length of the air passage in a thickness direction of the power storage device. Power storage device.   The power storage device according to any one of claims 10 to 15, wherein the second portion has a pillar formed in the ventilation path.   The power storage device according to any one of claims 10 to 16, wherein an outer surface of the second portion is a pear ground.   The power storage device according to any one of claims 10 to 17, wherein at least one ridge extending in a circumferential direction is formed on an outer surface of the second portion.   The power storage device according to any one of claims 10 to 18, wherein, in the second portion, an end of the end opposite to the first portion has a rounded corner in plan view. The outer shape of the cross section of the second portion having the center line of the ventilation path as a normal line is a polygon,
The power storage device according to any one of claims 10 to 19, wherein corners of the polygon are rounded. Each of the first portion and the second portion is made of a different material,
The power storage device according to any one of claims 10 to 20, wherein a melting point of the material of the first portion is higher than a melting point of the material of the second portion.   The power storage device according to any one of claims 10 to 21, wherein a plane is formed on at least a part of an outer surface of at least one of the first portion and the second portion.

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