JP2017220656A - Air-permeable packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-permeable packing hardly permitting transmission of moisture and readily permitting transmission of gas, for use in an air-tight container in which gas is generated inside and the generated gas at a high temperature invites a pressure rise in the air-tight container, to discharge the generated gas out of the air-tight container.SOLUTION: In an air-permeable packing, low melting point elements 3A are dispersed in gas permeating base material 3D to cause the low melting point elements 3A to prevent permeation of moisture and gas and to melt the low melting point elements 3A at or above their melting point thereby to cause a gas bypass route to be created within the gas permeating base material 3D by the gas pressure. This air-permeable packing 3 is arranged in an air-tight container body 1 having minute ventilation holes 2 with the result that the air-permeable packing is given functions to have a state in which the ventilation holes 2 is blocked by not allowing the low melting point elements 3A to be molten and a state in which the ventilation holes 2 are opened by the gas bypass route generated at or above the melting point and temperature.SELECTED DRAWING: Figure 1

Description

The present invention relates to a breathable packing that makes it difficult for moisture to permeate and facilitates gas permeation.

Gas is generated inside, and when the temperature rises, the generation of gas becomes active and the pressure in the sealed container rises due to the generated gas, and the sealed container expands due to the pressure in the sealed container, Sealed container may burst. As such a sealed container in which gas is generated inside and the pressure of the sealed container increases when the temperature of the sealed container becomes high and the pressure in the sealed container increases due to the generated gas, for example, a capacitor having an electrolyte or lithium In sealed electrochemical devices such as batteries, the electrolyte is sealed so that it does not leak out of the sealed container, so it can be repeatedly charged and discharged, left at high temperatures, shorted, overcharged, reversed The electrolytic solution is decomposed by charging, etc., and gas such as hydrogen gas or carbon dioxide gas is generated in the sealed container. The gas is accumulated in the sealed container, so that the internal pressure increases rapidly, and the sealed container Therefore, a breathable packing that discharges the generated gas to the outside of the sealed container appropriately so that the generated gas does not accumulate excessively in the sealed container is desired. It has been. In addition, even in a lithium battery in which a solid electrolyte is hermetically housed in a sealed container instead of an electrolyte, the sealed container prevents moisture and gas from passing through from outside, so the solvent contained in the solid electrolyte in the sealed container As the gas is generated and accumulated in the sealed container, the internal pressure suddenly rises and the sealed container may expand or rupture. Therefore, there is a demand for a breathable packing that appropriately discharges the generated gas to the outside of the sealed container so that it does not accumulate excessively.

It is effective in preventing the bursting of containers containing gas or liquid or solid content, and even if the container falls over and gets wet with liquid contents, the liquid-imperviousness and air permeability are not impaired over a long period of time. In addition, as a breathable packing which does not leak the contents, in Patent Document 1, a packing substrate made of a polyolefin having a microporous film made of a polyolefin having an intrinsic viscosity of 3 dl / g or more and a gas passage is formed. Ventilation that prevents gas or liquid from leaking when it is used for packing caps of containers that contain gas or liquid or solid as a content. Sex packing has been proposed.

However, in the breathable packing of Patent Document 1, the porosity of the microporous film laminated on the packing substrate made of polyolefin having a gas flow path so as to have a balance between non-liquid permeability and breathability, It is necessary to set the air permeability and average pore diameter.

Further, as a sealed electrochemical device such as a capacitor having an electrolytic solution or a lithium battery, in Patent Document 2, a through-hole penetrating the front and back is formed in a sealing plate of the electrolytic capacitor, and the through-hole is formed with foamed silicon rubber. Sealed with, allows only the gas generated inside the electrolytic capacitor to permeate and discharge (exhaust) it to the outside, so that the increase of internal pressure can be mitigated and the safety valve operation can be delayed, thereby improving the life characteristics of the electrolytic capacitor It has been proposed.

However, in the electrolytic capacitor of Patent Document 2, foamed silicon rubber uses a property that gas permeability is high and electrolyte solution does not permeate, but gas is generated inside the electrolytic capacitor as the temperature rises rapidly. Consideration to become prosperous is necessary. That is, consideration must be given to the fact that the safety valve operation of the electrolytic capacitor cannot be delayed unless the gas is discharged to the outside of the electrolytic capacitor following the generation of the gas at a high temperature.

Further, in Patent Document 3, in order to reduce the gas tightness inside the battery at high temperature and dissipate the gas generated inside the battery to the outside to prevent deterioration of the discharge performance of the battery, the upper surface of the sealing gasket and the positive terminal plate A dry battery has been proposed in which a packing impregnated with paraffin set to have a melting point of 40 to 45 ° C. is sandwiched between the lower surface of the peripheral portion and the leakage resistance is improved.

However, in Patent Document 3, the packing impregnated with paraffin at low temperature or normal temperature is well adhered to the upper surface of the sealing gasket and the lower surface of the peripheral edge of the positive terminal plate, and is highly airtight, but at a high temperature of 40 ° C. or higher. This paraffin melts and flows, and the adhesion between the upper surface of the packing and the sealing gasket and the lower surface of the peripheral edge of the positive terminal plate is reduced to dissipate the gas generated inside the battery. Care must be taken to prevent the paraffin from flowing out.

Further, in Patent Document 4, in a thin battery in which a solid electrolyte or gel electrolyte is housed in a sealed container instead of an electrolyte, the sealed container body is an exterior material made of a moisture-proof multilayer film including a resin layer and a metal foil layer, Thin batteries such as lithium batteries that have been sealed by heat sealing or adhesive resin have been proposed. Due to the high energy density of this thin battery, in the unlikely event that internal short-circuiting or destruction due to external force occurs, there is a risk that the battery will be discharged in a short time and the battery will become hot. The vapor pressure of the solvent contained in the electrolyte increases, and the internal pressure of the battery becomes higher due to the solvent-derived gas. Therefore, a cut is made in the resin layer inside the moisture-proof multilayer film, and when the internal pressure of the battery rises, this cut portion tears and breaks linearly to discharge the gas in the battery and prevent the battery from bursting. A safety valve is formed.

However, in Patent Document 4, since the safety valve is used by the exterior material being cleaved, in order for the internal pressure of the battery to rise and the cut portion of the exterior material to tear, the internal pressure needs to increase as the exterior material expands. Therefore, it is necessary to safely discharge the gas by managing the relationship between the internal pressure of the battery due to gas generation, the cleavage of the exterior material, and the gas discharge. In addition, due to the cleavage of the exterior material, an appropriate function as a thin battery is not achieved.

Japanese Patent Laid-Open No. 2002-347821 JP 2001-15391 A Japanese Utility Model Publication No. 62-31369 JP 11-31505 A

In order to solve the above-described problems, the present invention provides a gas container in which a gas is generated, and when the temperature becomes high, the generation of gas increases and the generated gas increases the pressure in the closed container. An object of the present invention is to provide a breathable packing that makes it difficult for moisture to permeate and allows the generated gas to be discharged out of the sealed container by using a transmissive substrate and a low melting point element.

The air-permeable packing according to claim 1 of the present invention is used for a sealed container in which gas is generated and gas is actively generated and the pressure in the sealed container is increased by the generated gas. A gas-permeable packing that discharges the gas to the outside of the sealed container in the process of increasing the pressure in the sealed container, wherein the gas-permeable packing disperses low-melting-point elements in a gas-permeable substrate, and the low-melting-point elements The gas bypass passage that prevents the moisture and gas from permeating and melts the low melting point element at a temperature equal to or higher than the melting point and allows the gas to permeate the gas permeable substrate by the gas pressure is generated. The air-permeable packing is disposed in a sealed container body having a vent hole made of a hole to close the vent hole without melting the low melting point element, and to a temperature higher than the melting point. Characterized in that a function of a state for opening the vent by the gas bypass passage which is generated by the pressure. The invention described in claim 2 is the breathable packing according to claim 1, wherein the breathable packing is disposed inside a sealed container body having a vent hole made of fine holes. The invention described in claim 3 is the breathable packing according to claim 1 or 2, wherein the gas-permeable base material is composed of a nonwoven fabric sheet. The invention described in claim 4 is the breathable packing according to any one of claims 1 to 3, wherein the low melting point element is composed of a low melting point olefin compound. The invention according to claim 5 is the air-permeable packing according to any one of claims 1 to 4, wherein the air-permeable packing is provided inside the sealed container body having the air holes made of the fine holes via a space. It is characterized by arranging and using.

The air-permeable packing of the present invention is used in a sealed container in which gas is generated and gas is actively generated and the pressure in the sealed container rises due to the generated gas. A gas-permeable packing that discharges the gas to the outside of the hermetic container in the process of rising, wherein the gas-permeable packing disperses low-melting-point elements in a gas-permeable base material and allows moisture and gas to permeate through the low-melting-point elements. The low-melting point element is melted at a temperature equal to or higher than the melting point, and a gas bypass passage is formed to allow gas to permeate into the gas-permeable substrate by gas pressure. The air-permeable packing is disposed in a sealed container body having a structure in which the low-melting point element is closed without melting the low-melting point element, and is generated at a temperature and pressure higher than the melting point. By providing the function of opening the vent hole with the gas bypass path, the vent hole is normally closed to prevent moisture from permeating and preventing gas from permeating. When the gas becomes active, the gas vent is opened through the gas bypass passage, and the gas is discharged from the gas vent to the outside of the airtight container so that the gas does not accumulate in the airtight container. The permeable substrate can be returned to a state in which moisture and gas are not permeated by the low melting point element, and the vent hole is closed to prevent moisture and gas from permeating.

It is AA sectional drawing which expanded the structure of the air permeable packing used for an airtight container main body in Embodiment 1 of this invention shown in FIG. It is a top view of FIG. It is sectional drawing which shows the state which breathable packing received temperature and pressure beyond melting | fusing point in Embodiment 1 of this invention. It is sectional drawing to which the site | part of the low melting point element of the air permeable packing of this invention was expanded. FIG. 5 is a plan view of FIG. 4. It is sectional drawing of the experimental apparatus which fuses a low melting-point element with the air permeable packing of this invention. It is a top view of the photograph which photoed the breathability packing of the state where the low melting point element of the present invention was not melted with the measuring microscope. It is a top view of the photograph which image | photographed the air permeable packing of the state which fuse | melted the low melting point element of this invention with the measurement microscope. It is sectional drawing which shows the sealing type electrochemical device using the air permeable packing of this invention. It is BB sectional drawing which expanded the structure of the air permeable packing used for an airtight container main body in Embodiment 2 of this invention shown in FIG. It is a top view of FIG. It is CC sectional drawing shown in FIG. 13 which expanded the structure of the air permeable packing used for an airtight container main body in Embodiment 3 of this invention. FIG. 13 is a plan view of FIG. 12. It is sectional drawing which shows different embodiment of the sealed electrochemical device using the air permeable packing of Embodiment 3 of this invention.

(Embodiment 1)
With reference to FIGS. 1-5, the structure of a breathable packing is demonstrated.

1 and 2, reference numeral 1 denotes a part of the sealed container body, and the sealed container body 1 has a ventilation hole 2 made of fine holes. The vent hole 2 is a hole having a circular cross section with a diameter of 0.5 to 100 μm that penetrates the inside and outside of the sealed container body 1, and is formed so as to hardly allow moisture to permeate. In this case, the air holes 2 may be set such that the gas is permeated less easily in combination with the air-permeable packing 3. An air-permeable packing 3 is disposed on the inner side (the lower surface in FIG. 1) of the sealed container body 1. This breathable packing 3 is made by dispersing a low melting point element 3A having a melting point of 40 to 120 ° C. in a gas permeable substrate 3D. In this case, the gas-permeable base material 3D is a rectangular or circular sheet having a thickness of about 0.2 mm, and a material through which moisture and gas permeate through a minute space between the upper surface and the lower surface. It is a material such as polyphenylene sulfide (PPS) resin, polypropyne (PP) resin, aluminum, nonwoven fabric made of glass fiber material, cloth, fine porous or single-hole film, and paper. The gas permeable substrate 3D is filled with a low molecular weight polyethylene wax, paraffin, a low melting point olefin compound or the like, and the low melting point element 3A is dispersed in the gas permeable substrate 3D. The breathable packing 3 made in this way is fixed to the bottom portion (bottom) of the support 4 made of a bottomed cylinder with one end open, so that the breathable packing 3 is attached to the support 4. A space 4 </ b> A is formed inside the support 4 so as to constitute the bottom. The support 4 is formed in a cylindrical shape or a rectangular tube shape so that one end is open and the bottom of the other end is opened and the breathable packing 3 is fixed to the bottom. It is made of a metal material or a synthetic resin material that does not allow moisture or gas to permeate. The support 4 is fixed to the inner side (lower surface in FIG. 1) of the sealed container body 1 so that the air-permeable packing 3 is exposed through the space 4A in communication with the air holes 2. A protective sheet 5 is disposed inside the sealed container body 1. The protective sheet 5 is made of a material similar to the material of the gas permeable substrate 3D and has a rectangular or circular shape with a thickness of about 0.2 mm. In FIG. It is fixed so as to close the vent hole 2 on the inner side (lower surface in FIG. 1), and as a result, the opening portion (opening end) of one end of the support 4 is blocked by this protective sheet 5. Show. In this case, the protective sheet 5 may be fixed in advance so as to close the open end of the support 4, and the support 4 may be fixed together with the protective sheet 5 to the inside of the sealed container body 1. In this way, a breathable packing block 10 is obtained in which the breathable packing 3 is fixed to the inside of the sealed container body 1 via the space 4A. The breathable packing 3 has the low melting point element 3A on the gas permeable substrate 3D. Since they are dispersed, the low melting point element 3A is in a state where moisture and gas are not allowed to pass therethrough. The protective sheet 5 is useful for protecting the melted low melting point element 3A from scattering into the vent hole 2 of the sealed body 1, but may be omitted.

Next, in FIG. 3, when the air-permeable packing 3 disposed inside the sealed container body 1 is subjected to a temperature and pressure P above the melting point in the sealed container, the low melting point element 3A melts at a temperature above the melting point. Under the pressure P, low melting point element removing portions 3B and 3C are formed on the upper and lower surfaces of the gas permeable substrate 3D, respectively. The low melting point element removing unit 3B and the low melting point element removing unit 3C indicate that the upper surface and the lower surface of the gas permeable base material 3D communicate with each other, and a gas bypass passage that allows gas to pass through the gas permeable base material 3D. Thus, the air-permeable packing block 10 that is in a state of opening the air holes 2 is obtained.

4 and 5 show a part of the low melting point element 3A of the breathable packing 3 in an enlarged manner. When the breathable packing 3 receives a temperature and a pressure P higher than the melting point in the sealed container, the low melting point element 3A is shown. As described above, a part of the low-melting-point element removal portions 3B and 3C at a temperature and a pressure equal to or higher than the melting point, and a gas bypass path is generated inside the gas-permeable base material 3D.

FIG. 6 shows a gas permeable base material 3D made of a polyphenylene sulfide (PPS) nonwoven fabric, in which a paraffin wax low melting point element 3A is infiltrated, and a film having a thickness of 0.2 mm is used as the air permeable packing 3. An experimental apparatus is shown in which the low melting point element 3A is melted to form the low melting point element removal portions 3B and 3C. In this experimental apparatus, the temperature was set to 80 ° C., the pressure P was set to 0.1 MPaG, the heated / pressurized air was sent from the lower surface to the upper surface, and the upper surface of the breathable packing 3 was The breathable packing 3 was observed using a Nikon measuring microscope MM-800) C.

FIG. 7 is a photograph obtained by observing the upper surface of the breathable packing 3 in a state where the low melting point element 3A is not melted with a measuring microscope. FIG. 8 is a view showing that the low melting point element 3A is melted and the low melting point element removing portion 3B is formed. It is the photograph figure obtained by observing the upper surface of the air-permeable packing 3 of the formed state with a measurement microscope. In FIG. 8, low-melting-point element removal portions 3 </ b> B having a small diameter, which are three gas bypass passages surrounded by a broken line ○ on the upper surface of the air-permeable packing 3, can be confirmed.

(Principle of moisture impermeability and gas permeation of breathable packing)
In FIG. 1 to FIG. 5, the air-permeable packing is applied to the closed container body 1 having the air holes 2 made of fine holes so as to make it difficult to permeate moisture. Since the element 3A is dispersed, a gas barrier that prevents the low-melting point element 3A from blocking moisture and gas by closing the micropores or gaps of the gas-permeable substrate 3D at a temperature at which the low-melting point element 3A does not melt, that is, at room temperature. Thus, the gas permeable base material 3D acts to block the vent hole 2 of the sealed container body 1 and make it difficult for moisture and gas to permeate through the vent hole 2. By this action, the sealed container makes it difficult for moisture and gas to permeate at room temperature. Next, when the airtight container body 1 reaches the melting temperature of the low melting point element 3A, that is, a high temperature, the low melting point element 3A is in a molten state, and the blocking action of the low melting point element 3A is weakened through the fine holes or gaps of the gas permeable substrate 3D. When the gas pressure is received in this state, a portion where the low melting point element 3A is removed from the fine hole or gap of the gas permeable substrate 3D is generated by the gas pressure, and the gas permeable group is generated by this portion (low melting point element removing portion). A fine hole or gap in the material 3D is opened to form a gas bypass path in the gas permeable base material 3D, and the vent hole 2 of the sealed container body 1 closed by the gas permeable base material 3D is opened. It acts to make gas difficult to permeate from the gas. Next, when the airtight container body 1 is lowered to a temperature at which the low melting point element 3A does not melt, the low melting point element 3A closes the micropores or gaps of the gas permeable base material 3D to form a gas barrier. The air vent 2 of the sealed container body 1 is closed, and the state is restored so that moisture and gas are hardly transmitted through the air vent 2. In this way, the gas can be transmitted through the air-permeable packing according to the temperature and internal pressure of the sealed container body 1. Depending on the temperature, an open / close cycle between a state in which gas is not permeated and a state in which gas is permeated is obtained.

(Use of breathable packing)
FIG. 9 shows a sealed container body in which the air-permeable packing of the present invention is used, formed in a sealed container of a sealed electrochemical device having an electrode element and an electrolytic solution so as not to allow moisture such as water vapor to permeate. An example of use in a sealed electrochemical device that facilitates discharge of gas generated inside to a sealed container will be described.

FIG. 9 shows a sealed electrochemical device in which a pair of electrode terminals 100 and 100 are arranged side by side on a lid that becomes the sealed container body 1, and this sealed electrochemical device is a capacitor or a lithium battery having an electrolytic solution 104. A joining member such that a lid (sealed container body 1) made of a synthetic resin material having a disc shape (including an ellipse) or a rectangular shape closes a cylindrical or rectangular box-shaped case 11 having an open end. 12 constitutes a sealed container of the sealed electrochemical device joined together. Inside the sealed container, the connection portion 101 of the electrode terminal 100, the lead 102 electrically connected to the connection portion 101, the electrode element portion 103 electrically connected to the lead 102 and the electrolyte 104 are sealed and accommodated. Has been. As described above, in a sealed electrochemical device such as a capacitor or a lithium battery having the electrode element portion 103 and the electrolytic solution 104, the electrolytic solution 104 is hermetically sealed so as not to leak out. Repeatedly, left at high temperature, or the electrolyte solution 8 is decomposed by short circuit, overcharge, reverse charge, etc., and gas such as oxygen and carbon dioxide is generated, and the internal pressure rapidly increases due to accumulation of the gas. There is a possibility that the lid body and the box-shaped case 11 that will become the sealed container body 1 will rise or rupture. In order to prevent the generated gas from accumulating excessively in the sealed container, a lid (the ventilating packing block 10 formed on the lower surface of the lid body with the vent hole 2 formed in the sealed container body 1 and the like) is used. Preventing moisture from permeating and preventing the gas generated in the sealed container from being appropriately discharged from the vent hole 2 to the outside of the lid as the sealed container body 1 and continuing to accumulate in the sealed container. Although not shown in the figure, the sealed container of the above-mentioned sealed electrochemical device may be provided with a safety valve for releasing the gas by opening the sealed container at a high pressure in the sealed container.

(Embodiment 2)
10 and 11 show different configurations in which the air-permeable packing described in the first embodiment is arranged in the airtight container body based on the principle of moisture impermeability and gas permeation.

10 and 11, a vent hole 2 made of a through hole of the sealed container main body 1 similar to that of the first embodiment is provided, and a space 2A having a large diameter is formed inside (lower part in FIG. 11). Has been. Protective sheets 6 and 7 are fixed to the upper and lower surfaces of the vent hole 2 of the sealed container main body 1, respectively. The shape of these protective sheets 6 and 7 is a rectangular or circular shape with a thickness of about 0.2 mm, and the material thereof is the same material as the material of the gas permeable substrate 3D like the protective sheet 5 shown in the first embodiment. is made of. In addition, a breathable packing 3 is disposed in the space 2A. The breathable packing 3 is spaced from the vent hole 2 on the upper surface and spaced from the protective sheet 7 on the lower surface. In this case, the protective sheet 6 protects the low-melting point element 3A melted from the vent hole 2 from splashing outside the sealed body 1 (upper part in FIG. 10), and the protective sheet 7 has the breathable packing 3 inside the sealed container. This is useful for protecting immersion in the electrolyte solution (the electrolyte solution in the lower part of the sealed container body 1 in FIG. 1), but may be omitted.

In this way, a breathable packing block 10 is obtained. In this case, the air-permeable packing 3 is made of the same material as that of the first embodiment, and the thickness of the sealed container body 1 is increased, but the configuration can be simplified.

(Embodiment 3)
12 and 13 show different configurations in which the breathable packing is arranged in the sealed container body based on the principle of moisture impermeability and gas permeation of the breathable packing described in the first embodiment.

12 and 13, the sealed container body 1 is made of an inner layer 1A made of a heat-sealing resin such as a polypropylene resin as in Patent Document 4, a metal foil layer 1B such as aluminum, a polyethylene terephthalate resin, etc., but an outer layer 1C. It is made of a moisture-proof multilayer film with laminated layers. The airtight container body 1 has a vent 2 comprising a line-shaped cut 2B passing through the outer layer 1C and the metal foil layer 1B, and a space 2A having a diameter larger than the cut 2B in the inner layer 1A in communication with the cut 2B. Is formed. The air-permeable packing 3 similar to the embodiment 1 or 2 that closes the air hole 2 via the space 2A is directly fixed to the inner side (the lower surface in FIG. 12) of the airtight container body 1, and the air-permeable packing block 10 is provided. can get.

(Different embodiments of the use of breathable packing)
FIG. 14 shows a sealed electrochemical device using the breathable packing of Embodiment 3, which is formed in a sealed container of a sealed electrochemical device having an electrode element and a solid electrolyte as a sealed container body in which the breathable packing is used. An example of use in a sealed electrochemical device that makes it easy to discharge the gas generated in the sealed container so as not to allow moisture such as water vapor to pass through will be described.

In FIG. 14, the sealed container body 1 made of a moisture-proof multilayer film is on the upper side, and the sealed container body 11 made of a similar moisture-proof multilayer film is on the lower side, and electrode terminals 100 and 100 are provided on the respective end faces. The hermetic container body 1 and the hermetic container body 11 are thermally welded via the connection portion 101 of the electrode terminal 100 to constitute a hermetic container. Inside this sealed container, a lead 102 electrically connected to the connection part 101 of the electrode terminal 100, an electrode element part 103 electrically connected to the lead 102 and a solid electrolyte 105 are sealed and accommodated. Thus, in a sealed electrochemical device such as a lithium battery having the electrode element portion 103 and the solid electrolyte 105, it is sealed so as to make it difficult for moisture and gas to permeate. The solid electrolyte 105 is decomposed by being left at a high temperature, short-circuited, overcharged, reverse charged, etc., and gas is generated. By accumulating the gas, the internal pressure suddenly increases, and the sealed container body 1 and the sealed container body 11 may swell or rupture. In view of this, moisture such as water vapor is formed by using the air-permeable packing block 10 formed on the lower surface of the sealed container main body 1 with the vent hole 2 formed in the sealed container main body 1 so that the generated gas does not accumulate in the sealed container. It is possible to prevent the gas from continuing to accumulate in the sealed container by preventing the gas from permeating through or by appropriately discharging the gas generated in the sealed container from the vent hole 2 to the outside of the sealed container.

In the first to third embodiments, the low melting point element 3A dispersed in the gas permeable base material 3D closes the fine holes or gaps of the gas permeable base material 3D with temperature to form a gas barrier or open to form a gas bypass path. It is necessary to consider the fine holes or gaps of the gas permeable substrate 3D and the distribution of the dispersion of the low melting point element 3A so that the action of returning to the gas barrier can be performed. It is also necessary to set the low melting point element 3A so that it does not scatter outside the sealed container due to the presence or absence of gas or the gas pressure in the container body.

Further, although not shown, the breathable packing may be disposed on the upper surface of the sealed container body 1 having the vent holes 2 made of fine holes, that is, outside the sealed container body 1.

The air-permeable packing of the present invention is used for a sealed container in which gas is generated at a high temperature and gas is actively generated, and the pressure in the sealed container increases due to the generated gas. It is useful as a sealed electrochemical device such as a capacitor or a lithium battery having an electrolytic solution or a solid electrolyte therein.

DESCRIPTION OF SYMBOLS 1 Airtight container body 2 Vent hole 3 Breathable packing 3A Low melting point element

Claims (5)

Gas is generated inside, and when the temperature rises, the generation of gas becomes active, and the generated gas increases the pressure in the sealed container, and the gas in the process of increasing the pressure in the sealed container A gas-permeable packing that disperses low-melting-point elements in a gas-permeable base material so that moisture and gas cannot be permeated by the low-melting-point elements. The low-melting point element is melted at a temperature equal to or higher than the melting point, and a gas bypass path is generated inside the gas-permeable substrate by gas pressure, and the air-permeable packing is provided in a sealed container body having vent holes made of fine holes. The vent hole is opened by the gas bypass path generated at a temperature and pressure higher than the melting point and the state in which the vent hole is closed without melting the low melting point element. Breathable packing, characterized in that a function with that state. The breathable packing according to claim 1, wherein the breathable packing is disposed inside a sealed container body having a vent hole made of fine holes. The breathable packing according to claim 1 or 2, wherein the gas permeable substrate is formed of a nonwoven fabric sheet. The breathable packing according to any one of claims 1 to 3, wherein the low melting point element is composed of a low melting point olefin compound. The breathable packing according to any one of claims 1 to 4, wherein a breathable packing is disposed inside a sealed container main body having a vent hole made of fine holes through a space. .

Images