Storage container and storage method

Abstract

[Problem] To provide a storage container having a simple structure, requiring no power source, capable of maintaining a low dew point environment inside the container over a long period of time, and capable of being easily transported. [Solution] A storage container according to the present invention is an airtight storage container having a door and a main body, and maintains a low dew point environment inside the container through disposition of a honeycomb filter carrying an adsorbent. Further, the honeycomb filter is made replaceable, is accommodated in an accommodation section, and is detachably attached to the storage container. Further, a door having a magnetic gasket is adopted, the door being easily openable and closable with excellent airtightness while having a simple structure.

Description

Storage Container and Storage Method

[0005]

[0001] The present invention relates to a storage container that can store stored items for a long period while maintaining them in a dry state.

[0002] Conventionally, a desiccator (humidity-proof storage) for storing stored items in a dehumidified storage has been known. By storing stored items that dislike moisture in a low-humidity state, deterioration, discoloration, rust, mold, etc. are prevented. Depending on the dehumidification (drying) method for maintaining a low humidity inside the desiccator and maintaining a dry state, desiccators are classified into various types.

[0003] The standard (desiccant / dehumidifier) type adsorbs water vapor in the storage with a desiccant or dehumidifier such as silica gel as described in Patent Document 1 to maintain a low humidity. For example, the box-type desiccator described in Patent Document 1 has an opening / closing door provided on the front surface of the main body, and a plurality of shelves for storing samples are arranged vertically inside. When the opening / closing door is closed, the entire desiccator is dehumidified through the ventilation holes of each shelf with a desiccant such as silica gel placed at the bottom of the desiccator. The standard type is the simplest, most common, easy to use, and inexpensive, but maintenance such as replacement or regeneration of the desiccant or dehumidifier that has adsorbed water vapor is required. It is suitable for applications that prevent moisture adhesion for a short period.

[0004] The auto-dryer type includes a solid polymer membrane method that electrolyzes and removes water vapor in the storage, a type that automatically regenerates a desiccant that has adsorbed water vapor as described in Patent Document 2 (desiccant method), etc. For example, the humidity-proof storage described in Patent Document 2 includes a dehumidification unit containing a desiccant, a ventilation section that connects the dehumidification unit and the inside of the storage, an exhaust section that connects the dehumidification unit and the outside of the storage and discharges air containing humidity from the dehumidification unit to the outside of the storage, and a control section that can exclusively open either the ventilation section or the exhaust section. The dehumidification unit further includes a storage section for storing the desiccant, and the desiccant stored in the storage section is configured to be replaceable, so it is possible to improve the dehumidification efficiency inside the humidity-proof storage. The auto-dryer type has excellent maintainability and many relatively inexpensive products. It is used to stably maintain a low humidity inside the storage for a long period.

[0005] Cooling dehumidifiers employ a highly efficient cooling dehumidification method (Peltier system), resulting in superior dehumidification speed. Water vapor inside the chamber is automatically discharged, making maintenance easy. However, both auto-dry and cooling dehumidifiers require a constant power supply. Membrane dryer types dehumidify by passing compressed air through a hollow fiber membrane. They do not require desiccants, offer excellent dehumidification performance, and allow for large-capacity storage of many items. While they only use compressed air and do not require a power supply, they do require air piping equipment.

[0006] When more powerful dehumidification is required, or when storing items that are sensitive to oxygen, the air composition should be controlled along with humidity. Gas displacement type dehumidifiers replace the air inside the chamber with an inert gas such as nitrogen or argon, creating a low-humidity environment. By continuously supplying a small amount of gas, the chamber maintains low humidity. Since it expels oxygen along with water vapor, it is suitable for storing items that are sensitive to both moisture and oxygen (easily oxidized). Equipment for supplying the inert gas into the chamber is required for use.

[0007] Vacuum (reduced pressure) desiccators use a vacuum pump to create a vacuum (reduced pressure) inside the chamber, expelling water vapor along with the air. Since oxygen is also expelled along with the water vapor, they are suitable for storing items that are prone to oxidation, similar to gas-purged desiccators. They are also sometimes used in experimental operations such as vacuum drying, degassing, and defoaming. They offer a high level of protection against moisture adhesion. While a separate vacuum pump is required for use, some products integrate the desiccator and pump.

[0008] Generally, desiccators offer higher dehumidification performance and lower internal humidity in the order of standard type, auto-dry type, and gas-purging type. They maintain a low humidity of 30-50% RH inside the cabinet at room temperature, preventing deterioration of stored goods. There are also ultra-low humidity cabinets that can maintain an internal humidity of 1% RH.

[0009] On the other hand, there is a demand for storing in a dry environment ICs, LED surface mount components, printed circuit boards, flexible circuit boards, etc., used in the mounting process of electronic components and semiconductors, as well as battery-related components and materials (active materials, binders, electrolytes, etc.) such as lithium-ion batteries, solid-state batteries, and capacitors (EDLC, Electric Double Layer Capacitor), organic EL-related components, metal powder materials for 3D printers, and reticles, lenses, wafers, etc., used in semiconductor manufacturing. For example, the storage case described in Patent Document 3 can accommodate electrode rolls in a battery manufacturing line while maintaining appropriate humidity.

[0010] Japanese Utility Model Publication No. 03-044251, Japanese Patent No. 7123422, Japanese Unexamined Patent Publication No. 2023-143415

[0011] However, the storage case disclosed in Patent Document 3 maintains low humidity by filling the case with gas or the like, and does not have a dehumidifying mechanism within the case itself. Furthermore, it is intended for relatively short-term storage, such as storing electrode rolls from the time they are made until unwinding by the unwinding device begins, and is unsuitable for long-term storage. Moreover, it is intended solely for storing electrode rolls of secondary batteries and is not suitable for storing other items.

[0012] To store such items in a low dew point environment for extended periods, a container capable of storing the items in a low humidity environment equivalent to a dry room, around -30 to -40°C DP (approximately 25°C, 1% RH), is required (hereinafter referred to as the "storage container"). (Hereafter, a dry environment equivalent to -30 to -40°C DP will be referred to as the "low dew point environment"). In such cases, an auto-dry type or a gas-purging type is generally chosen, but these require a power source to operate during storage, resulting in ongoing running costs. In other words, they cannot be used in locations without a power source. Furthermore, this type of storage container requires various auxiliary devices and equipment, incurring high initial costs and requiring a large installation space. Moreover, it is unsuitable for transporting the storage container while maintaining the stored items in a low dew point environment.

[0013] Therefore, standard (desiccant / dehumidifier) ​​type storage containers do not require a power source and are easy to use, as they only require replacing the dehumidifier. However, replacement is necessary when the water vapor adsorption of the desiccant reaches saturation, and they are suitable for moderate humidity levels of 30-50% RH, but their dehumidifying performance is low and they are not suitable for long-term storage. They are suitable for relatively small storage volumes and are not suitable for storing large items. Also, large storage containers require a large amount of desiccant. Silica gel is generally used as a desiccant, and there are types such as polyethylene film with holes, non-woven fabric, and sheet types, and some are designed to be easily replaced as dehumidifier cartridges or cassettes, but even so, regularly replacing the dehumidifier in a large desiccator is troublesome. Silica gel can be reused by heating and regeneration, but regeneration is also troublesome. Furthermore, silica gel is granular, and when used by filling it into a case, the surface area in contact with air tends to be small.

[0014] Typically, battery-related components and materials that require storage in a low-dew-point environment are temporarily stored in a dry room required for the manufacturing process. While they may sometimes be stored in airtight containers, such as the electrode roll storage case described in Patent Document 3, they are usually stored in relatively less airtight containers, and these containers are then stored in the dry room. Alternatively, they may be stored without containers, either in the dry room or in a localized dry booth for temporary storage. Therefore, dry rooms require storage space in addition to the manufacturing line, contributing to their larger size. Larger dry rooms require a larger management area, necessitating more advanced management techniques and a greater number of auxiliary devices and equipment. Furthermore, even during periods when the manufacturing line is not operating, the dry room must maintain a low dew-point environment solely for the purpose of storing the materials. Maintaining a low-dew-point environment in a dry room requires a significant amount of electricity as its volume increases, resulting in increased energy and running costs. This electricity requirement is one of the factors contributing to the increased production costs of products such as batteries. Furthermore, even when setting up a localized drying booth for temporary storage, it is necessary to maintain a low dew point environment for storage, which incurs energy and running costs. Space and equipment for setting up the localized booth are also required.

[0015] Therefore, there has been a demand to store items in a low dew point environment even outside of a dry room or in the absence of a dry room. As a result, storage containers specifically designed for low humidity (e.g., 1% RH or less) have been adopted, among auto-dry and gas-purging types. This makes it possible to move items stored in the dry room to these containers, thereby increasing usable space. They can also be used as temporary storage during dry room maintenance. However, as mentioned above, auto-dry and gas-purging type storage containers require power and auxiliary equipment, making them difficult to transport by truck or other means.

[0016] In view of the above circumstances, the main objective of the present invention is to provide a storage container that does not require a power source, can maintain a low dew point environment of -30 to -40°C DP inside the container for a long period of time even outside a dry room, can easily replace the desiccant without requiring as frequent replacement as standard type storage containers, has a simple structure, can store small to large items, and can be easily moved and transported.

[0017] The storage container of the present invention is an airtight storage container having a door and a body, and is characterized by maintaining a low dew point environment inside the container by arranging a honeycomb filter carrying an adsorbent.

[0018] The storage container of the present invention uses a honeycomb filter to adsorb moisture inside the container and dehumidify it, and employs a magnetic gasket door. In this way, by making improvements to the desiccant and structure, it has become possible to maintain a low dew point environment of -30 to -40°C DP (around 25°C, 1% RH) inside the container, which was impossible with conventional standard types.

[0019] The honeycomb filter is replaceable and is housed in a compartment that allows it to be detachably attached to the storage container. This allows the container to maintain a low dew point environment for extended periods by replacing the honeycomb filter if the humidity or dew point inside the container tends to rise. The honeycomb filter is regenerative through heat drying and can be reused repeatedly. Pre-dried and regenerated honeycomb filters can be kept separately from the storage container in a dry state. These separately stored honeycomb filters can be used when needed, and the storage container itself can maintain a low dew point environment without power. By handling the honeycomb filter separately from the storage container, it can be dried and regenerated at any location and time. Furthermore, the honeycomb filter can be stored in a sealed case in a dry state, allowing for transport of the entire case.

[0020] The storage container of the present invention requires no power supply and can maintain a low dew point environment equivalent to that of a dry room. Because it requires no power supply, there are no running costs, resulting in energy savings. Therefore, production costs for products such as batteries can be reduced. Furthermore, because there are no moving parts, it generates no noise or vibration and boasts excellent durability. Moisture inside the container is adsorbed by a honeycomb filter, preventing the release of water droplets (condensate). In addition, because no auxiliary devices or equipment are required, the installation area is smaller compared to conventional auto-drying or gas-purging type storage containers, reducing initial costs.

[0021] Furthermore, since the storage container of the present invention can be used in an environment without power, it is possible to transport the storage container itself to a remote location by truck or the like while maintaining a low dew point environment. In the case of inter-process transfers on a manufacturing line, even when it is necessary to transfer work-in-progress or materials that are susceptible to moisture to the next line by passing through the external environment outside the dry room, these can be placed in the storage container of the present invention and transported together with the container, allowing them to be transferred to the next line while maintaining a low dew point environment.

[0022] The storage container of the present invention employs a magnetic gasket door, resulting in a simple structure that offers excellent airtightness and easy door opening and closing. Since no fasteners such as latches are required, it can also be opened and closed by machines (robots) in automated factories.

[0023] Furthermore, by equipping the storage container of the present invention with a thermometer, hygrometer, and dew point meter and transmitting signals to a monitoring terminal, the temperature, humidity, and dew point inside the container can be managed remotely. Moreover, by adjusting the size, number, and cell size of the honeycomb, as well as the type and amount of adsorbent, according to the storage period, the capacity of the storage container, and the required humidity (required dew point temperature), fine-tuned humidity (dew point) control can be performed inside the storage container.

[0024] Furthermore, the storage container of the present invention allows for storage outside of a dry room or in the absence of a dry room. Therefore, it is possible to relocate items that were previously stored inside a dry room, thereby increasing the available space. Alternatively, since the space previously required for storage inside the dry room is no longer needed, the dry room can be made smaller. During periods when the production line is not in operation or when the dry room is undergoing maintenance, work-in-progress, materials, and other items that require storage in a low dew point environment can be stored in the storage container of the present invention without operating the dry room. As a result, the amount of electricity required for storage in the dry room that was previously needed can be reduced, leading to energy savings and cost reductions.

[0025] Figure 1 is a perspective view showing an example of the configuration of the storage container of the present invention. Figure 2 is a right side view showing an example of the configuration of the storage container of the present invention. Figure 3 is a plan view and an enlarged view of the door portion showing an example of the configuration of the storage container of the present invention. Figure 4 shows an example of the filter shape of the honeycomb filter of the storage container of the present invention. Figure 5 shows an example of the configuration of the honeycomb filter housing of the storage container of the present invention. Figure 6 is a diagram showing the measurement results of the dew point temperature inside the storage container in Embodiment 1 of the storage container of the present invention.

[0026] The embodiments for carrying out the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0027] Figure 1 is a perspective view showing an example of the configuration of the storage container of the present invention. The storage container 1 of the present invention can store items that require storage in a low dew point environment equivalent to -30 to -40°C DP (around 25°C, 1% RH), such as ICs, LED surface mount components, printed circuit boards, flexible circuit boards, etc. used in the mounting process of electronic components and semiconductors, battery-related components and materials (active materials, binders, electrolytes, etc.) such as lithium-ion batteries, solid-state batteries, and capacitors, organic EL-related components, metal powder materials for 3D printers, and reticles, lenses, wafers used in semiconductor manufacturing, and can maintain a low dew point environment inside the container for a long period of time. In the present invention, -30 to -40°C DP is defined as a "low dew point environment," but it is not limited to this, and may be in the range of -10 to -50°C DP as required. The items to be stored are not limited to those mentioned above, but may also include precision instruments, food products, chemicals, etc.

[0028] The storage container 1 has a door 2 and a body 3. The container can store precision instruments, food products, chemicals, powdered reagents, electronic components, lenses, and materials sensitive to moisture, and the air inside the container is adjusted to low humidity. The storage container 1 may have improved thermal insulation by using insulating materials. By using an insulating structure, rapid temperature changes in the atmosphere inside the container and the honeycomb filter can be efficiently prevented, and since the volume of the atmosphere inside the container is prevented, the intrusion of air is reliably prevented.

[0029] The storage container 1 is made of a material such as metal (steel, aluminum, stainless steel) or resin (acrylic (PMMA, Polymethylmethacrystalline) or polycarbonate (PC, Polycarbonate)), and the joints are sealed by welding or by using gaskets to create an airtight seal. Using stainless steel provides excellent durability and corrosion resistance. Using transparent resin makes it easy to see inside. An aluminum frame may be used as the frame of the storage container 1, and a plate material such as acrylic may be fitted into the frame groove to seal the inside of the container from the outside.

[0030] Door 2 is attached to the main body 3 by a hinge 4 so that it can be opened and closed. Door 2 is a magnetic gasket door, with a magnetic gasket 5 (a sealing material with a built-in magnet) attached to the door-side frame, and a metal plate to which a magnet will stick (hereinafter referred to as "magnetic metal plate") attached to the main body-side frame. When door 2 is closed, the magnetic gasket 5 and the magnetic metal plate 6 adhere tightly together by magnetic force, closing the door.

[0031] As shown in Figure 3, the magnetic packing 5 has a magnet 8 built into it. Its form is not particularly limited, but for example, a permanent magnet coated or packaged in a rectangular shape with a soft rubber, plastic, or silicone material that can exhibit elasticity and adhesion, or a rubber magnet can be used. A magnetic metal plate 6 is attached to the main body 3. The magnetic metal plate 6 is attached to the main body frame by adhesive or screw fixing. Alternatively, a groove may be made on the surface of the part of the main body 3 that contacts the door 2, and the magnetic metal plate 6 may be fitted into it. Various methods can be considered for attaching the magnetic packing 5 to the door 2, such as insert fixing, screw fixing, or fixing by passing it through a rail as a bar type, but it is not particularly limited as long as it is a method that allows for a tight seal between the magnetic packing 5 and the door frame without any gaps. The material of the magnetic metal plate 6 is not limited as long as it is magnetic. Usually it is an iron plate or a metal plate such as SUS, but SUS is preferable because it is less prone to rust. The material of the magnetic packing 5 is not particularly limited as long as it is flexible and increases airtightness, such as soft rubber.

[0032] By using a magnetic gasket door in this way, the door can be tightly fixed without the need for any other fasteners or fixing devices, providing excellent airtightness and allowing for easy opening and closing with one hand. When closing door 2, one end of door 2 (the fixed end) is rotatably fixed by the hinge 4, so the other end (hereinafter referred to as the "free end") that is not fixed by the hinge 4 should be lightly pressed against the main body. In this way, the magnetic metal plate 6 of the main body 3 of door 2 is attracted and bonded to the magnetic gasket 5 by magnetic force, and door 2 is fixed with high airtightness. Conversely, when opening door 2, simply apply a little force to the free end of the door and pull, and door 2 can be easily opened. In this way, opening and closing of door 2 is possible with simple operation and one-handed operation.

[0033] The area around the door inside the storage container is particularly susceptible to the effects of the outside air. The material that seals the door 2 and the main body 3 when the door is closed requires airtightness and flexibility to allow the door to open easily, prevent leaks, and contain low-dew-point air, as well as durability to maintain this function for a long period without tearing. By using a magnetic gasket door, these requirements can be met with a simple structure. By adjusting the clamping force (magnetic force) of the magnet 8 and the force of the hinge 4, the door can be opened with little force, while also maintaining a securely closed state, and the movement when opening and closing the door can be made smooth. Depending on the material, magnetic gaskets have excellent waterproofing and durability. Replacement and installation are also relatively easy.

[0034] In Figure 1, door 2 is shown as a left-opening door, opening from right to left, but it can also be a right-opening door, opening from left to right. It is not limited to a single door; it can also be a double door, opening from the center to the left and right, or a double door that can be opened from both sides, or an upward or downward opening door using a stay. Furthermore, the magnetic packing 5 may be attached to the main body 3 side and the magnetic metal plate 6 to the door 2 side. Basically, fasteners or other fixing devices are not required to maintain airtightness, but to improve the airtightness of the magnetic packing door, it may be fixed with fasteners (fixing devices) such as a sealing handle or snap lock. It may also be a door with a lock. When a double door, such as a left and right two-door type, is used, a central support column may not be provided in the opening, or may be removable, making it easier to store horizontally long items. A handle may be provided on door 2.

[0035] The size of the storage container 1 is not particularly limited, but it is preferable that the minimum size is 200 mm wide x 200 mm deep x 200 mm high, allowing it to store small items and be held by hand, and the maximum size is 2000 mm wide x 2000 mm deep x 2000 mm high, allowing it to be transported by truck or the like.

[0036] As shown in Figure 2, a honeycomb filter 7 is placed inside the storage container 1. The honeycomb filter 7 has a honeycomb structure formed by corrugating (creating waves) inorganic fiber sheets and laminating and bonding multiple sheets, and an adsorbent material such as silica gel or zeolite is supported on it. As shown in Figures 4(a) to (d), this honeycomb structure in the narrow sense includes a structure in which hollow hexagonal prisms resembling a beehive are arranged without gaps, but is not limited to this shape, and in the broad sense, it also includes a structure in which any hollow three-dimensional shape is arranged without gaps.

[0037] The honeycomb structure is lightweight, strong, has low pressure loss, and a large surface area. Therefore, compared to granular or pelletized desiccants (adsorbents) mainly used in standard (desiccant / dehumidifier) ​​type storage containers, the honeycomb filter 7 used in the storage container of the present invention has a larger contact area with air, allowing for more effective utilization of the adsorbent. As a result, dehumidification efficiency is improved compared to when granular adsorbents are used, and the amount of adsorbent used can be reduced. Therefore, it is possible to maintain a low dew point environment of -30 to -40°C DP (around 25°C, 1% RH) inside the container, which was not possible with conventional standard types. Furthermore, by using a honeycomb filter carrying an adsorbent instead of the granular desiccant used in standard types, the frequency of replacing the desiccant (adsorbent) can be reduced compared to standard type storage containers, and the regeneration of the desiccant (adsorbent) is easier.

[0038] Silica gel has adsorption properties over a wide range of humidity levels, from low to high. Zeolite has stronger adsorption capacity than silica gel, exhibiting particularly high adsorption capacity in low humidity levels. When zeolite is placed in a high-humidity space, it first absorbs moisture, reducing its ability to adsorb gases other than moisture, so using it in combination with silica gel is efficient. For example, if the dew point inside a container is relatively high, a honeycomb filter supported with silica gel can be used to absorb moisture and lower the dew point, and then it can be replaced with a honeycomb filter supported with zeolite to further lower the dew point inside the container or to adsorb gases other than moisture. Alternatively, honeycomb filters supported with silica gel and zeolite, respectively, can be used.

[0039] The honeycomb filter 7 adsorbs moisture inside the storage container 1, dehumidifying the container and maintaining a low dew point environment. The honeycomb filter 7, which carries the adsorbent material, adsorbs moisture and approaches saturation, and its moisture adsorption capacity (dehumidification performance) gradually decreases as storage time progresses. Therefore, it is preferable to configure the honeycomb filter 7 to be replaceable. That is, by temporarily detaching the housing section containing the honeycomb filter 7 from the storage container, the honeycomb filter can be easily replaced.

[0040] For example, as shown in Figures 5(a) and (c), if the honeycomb filter 7 is housed in a cartridge 10 as a housing and made pull-out type for easy, one-touch attachment and detachment, the filter can be easily and quickly replaced. As shown in Figure 5(b), multiple honeycomb elements 9 are arranged inside the cartridge 10 so that the cartridge 10 can be housed in the storage container 1. The cartridge 10 is provided with numerous ventilation holes such as slits and punches, and the housed filter elements 9 communicate with the inside of the container through these ventilation holes, allowing air from inside the storage container 1 to flow into the cartridge 10 and come into contact with the honeycomb filter 7. It is preferable, but not limited to, that ventilation holes be provided on all surfaces of the cartridge that come into contact with the inside of the container. The material of the cartridge 10 is not particularly limited, such as metal or resin, and may be fixed to the main body 3 with screws or the like.

[0041] The arrangement of the honeycomb filter 7 is not particularly limited, but the honeycomb filter 7 (storage section 10) may be configured to be located on the bottom surface of the container. This allows the honeycomb filter 7 to efficiently adsorb moisture-containing air that accumulates near the bottom surface of the container, enabling effective dehumidification of the air inside the container and maintaining low humidity inside the container. In addition, it may be located on the sides, top, back, or behind the door 2 of the storage container 1, or it may be located on multiple surfaces. The honeycomb filter 7 may be replaceable with the door 2 open, but it is preferable to replace it with the door 2 closed in order to prevent moisture from entering from the outside while the stored items are in storage. That is, it is preferable that the storage section 10 be removable even with the door 2 closed. For example, as shown in Figure 5(c), the cartridge 10 may be inserted by sliding it in from the vertical or horizontal direction. Alternatively, it may be installed on the back of the door 2 so that the cartridge 10 can be removed with a single touch by sliding it even with the door 2 closed. Furthermore, to prevent communication between the inside and outside of the storage container when attaching or detaching the housing containing the honeycomb filter 7, an airtight lid may be provided over the cartridge insertion port. The lid may be designed so that it closes when no cartridge is inserted, opens when a cartridge is inserted, and the insertion port is closed by the lid or the cartridge itself when a cartridge is inserted.

[0042] The size and number of honeycomb elements 9 constituting the honeycomb filter 7 and / or the honeycomb elements 9 are not limited. That is, the honeycomb filter 7 may be one large honeycomb element 9, or it may be composed of multiple honeycomb elements 9 arranged together. The moisture adsorption capacity and amount of moisture adsorbed can be adjusted by changing the size, number, cell size, type and amount of adsorbent material of the honeycomb filter 7 or honeycomb elements 9. Therefore, by changing these according to the storage period, the capacity of the storage container, and the required dew point temperature (humidity), the optimal honeycomb filter can be selected and finely adjusted. For example, if the required dew point temperature is low, the amount of zeolite supported can be increased, or the number of honeycomb elements 9 can be increased compared to normal. Also, when replacing the honeycomb filter 7, only a portion of the honeycomb elements 9 may be replaced.

[0043] The storage container of the present invention is excellent in maintaining a low dew point environment inside the container and keeping stored items in a dry state, but is not suitable for drying wet stored items. When the stored items are wet or contain a large amount of moisture, the ability of the storage container to remove water vapor may not be sufficient, and it may be difficult to keep the inside of the container at a low humidity. Therefore, it is desirable to store extremely wet stored items in the container after pre-drying them by ventilation drying or the like.

[0044] Zeolite and silica gel are regenerable adsorbents, and even when the honeycomb filter becomes saturated with moisture, it can be repeatedly used by heating regeneration or the like. The honeycomb filter 7 is preferably pre-heated and dried before installation. The heating temperature depends on the type of adsorbent, but is, for example, 80 to 200°C. It is also possible to put a heated and dried honeycomb filter at the same time as storing the stored items, but a pre-dried and regenerated honeycomb filter may be held separately from the storage container in a dry state, and replaced when storing the stored items or when the moisture adsorption capacity of the honeycomb filter decreases and replacement becomes necessary. Since the honeycomb filter 7 installed in the storage container has been pre-dried and regenerated, the honeycomb filter 7 adsorbs and removes the moisture remaining in the storage container or the moisture that enters the storage container, and the inside of the storage container is kept at a low dew point. Note that the drying and regeneration of the honeycomb filter may be performed not only by a temperature difference such as heating, but also by gas replacement or a pressure difference.

[0045] When storing items and simultaneously placing a heated and dried honeycomb filter at a high temperature, the temperature inside the container rises, requiring the stored items to have sufficient heat resistance to withstand this temperature. Even for items that can be stored under these conditions, the temperature rises due to the placement of the high-temperature honeycomb filter, creating convection within the container. Especially when the honeycomb filter is placed at the bottom, convection occurs from bottom to top, circulating air and efficiently adsorbing moisture onto the filter. Storing a heated and dried honeycomb filter in a storage container at a high temperature, followed by purging with a low-relative-humidity gas or nitrogen gas, can suppress the adsorption of moisture by the adsorbent material in the dried container, extending the time between honeycomb filter replacements. If there is a heat source, such as exhaust heat, near the storage container, after installation, the honeycomb filter inside the container may be heated and dried via a duct or similar means from the nearby heat source to enhance its adsorption function. Furthermore, increasing the pressure inside the container to a positive pressure higher than atmospheric pressure using a pump can prevent moisture from entering. If necessary, after storing the items, the gas inside the container may be replaced from air to an inert gas such as nitrogen, or a vacuum may be applied.

[0046] If pre-dried and regenerated honeycomb filters are kept in a dry state, separate from the storage container, they can be dried and regenerated by heating or other means at a location away from the storage container or at a different time than when they were stored, i.e., at any location or time. After drying and regeneration, they can be kept dry, for example, by placing them in a sealed case. Alternatively, they can be stored in a reduced pressure or vacuum container, a commercially available dry box or portable desiccator, or simply stored in a dry room, but are not limited to these methods.

[0047] If the case for placing the honeycomb filter is portable, it can be transported, which is convenient for transporting it together with the storage container or moving the honeycomb filter from the place where it is dried and regenerated to the place where the storage container is located. When it becomes necessary to replace the honeycomb filter at the location of the storage container, it can be taken out of the case at any time. Also, since the honeycomb filter can be dried and regenerated at any timing at an arbitrary location away from the storage container, for example, at a location where exhaust heat is generated such as a factory, by heating and drying the honeycomb filter with the exhaust heat, the energy-saving effect becomes extremely high. Note that the heat source is not limited to such exhaust heat, and it may be obtained from, for example, solar heat or geothermal heat. A heating regeneration device that can set and repeatedly use the honeycomb filter may be attached.

[0048] Inside the dry room, the heated and dried honeycomb filter can be stored as it is without being put into a sealed case. Also, by storing the honeycomb filter that has adsorbed moisture as it is in the dry room, the moisture adsorbed on the honeycomb filter is dehumidified by the relative humidity difference without heating and drying, so the honeycomb filter becomes in a dry state at the low dew point environment level of the dry room. Furthermore, when storing stored items in the storage container inside the dry room, the honeycomb filter that has been stored in the dry room is also placed and stored together, so that the inside of the storage container is in a dry state from the beginning of storage, and even if the storage container is taken out of the dry room, since the honeycomb filter is stored, the dry state can be maintained.

[0049] Even if the honeycomb filter in a state of having absorbed moisture is left in the container, it will not desorb moisture conversely. By making the intrusion of external moisture approach zero as much as possible, a low dew point environment can be maintained for a long period. Also, when the moisture adsorption ability of the honeycomb filter decreases, by configuring the honeycomb filter as a detachable housing part, it can be easily replaced, and a low dew point environment can be maintained for a longer period.

[0050] Since storage containers are generally airtight, the air inside the container remains stagnant without being replaced. However, even with airtightness, moisture from the outside air can enter from near the door. Also, the door may be opened and closed for a short time to retrieve stored items. In this case, the humidity inside the container will rise. At this time, for example, replacing the honeycomb filter with a new, dry one can quickly lower the elevated humidity inside the container back to the original low dew point environment. The area near the door is particularly susceptible to the effects of moisture from the outside air, so by focusing the honeycomb filter on the back of the door and close to the door inside the container, this effect can be mitigated.

[0051] By installing a thermometer, hygrometer, and / or dew point meter in the storage container and transmitting signals to a monitoring terminal, the temperature, humidity, and / or dew point inside the container can be monitored remotely. If the moisture adsorption capacity of the honeycomb filter decreases and the humidity and / or dew point inside the container tend to rise, replacing the honeycomb filter will lower the dew point inside the container again, enabling long-term storage.

[0052] In this way, the storage container of the present invention removes moisture from inside the container using a honeycomb filter, and the storage container itself does not require a power source, allowing it to maintain a low dew point environment without power. Furthermore, it achieves the maintenance of a low dew point environment that could not be achieved with conventional standard (desiccant / dehumidifier) ​​types, and makes the replacement and attachment / detachment of the honeycomb filter easier. In addition, because the storage container has a simple structure, it is easy to install and can be flexibly processed to any size and material. Conventional auto-dry type and gas-purging type storage containers are large in size and require a power source because they are equipped with auxiliary devices such as dehumidifiers and gas supply devices. The storage container of the present invention is compact and can be used even in places without a power source. In the storage container of the present invention, the honeycomb filter for dehumidification and maintenance of a low dew point environment inside the container is built into the container, and does not require auxiliary devices or equipment and does not require a power source, so it can be transported while maintaining a low dew point environment with only the storage container itself. Furthermore, compared to conventional dehumidification methods, it does not require electricity or replacement gas, so initial costs and running costs can be significantly reduced. This makes it possible to reduce the production costs of products such as batteries.

[0053] Furthermore, the storage container of the present invention can be used in an environment without power supply and has a simple structure, making it possible to move and transport the stored items together with the container. In addition, the use of a magnetic gasket door provides excellent airtightness, and the door can be opened and closed with light force without the need for tools. Therefore, it is useful for automation on the manufacturing line, such as moving the storage container or opening and closing the storage container by robot. It is also possible to deliver or transport the stored items to remote locations by truck or ship while maintaining a low dew point environment, and to pass the stored items through the external environment outside the dry room during the handover between processes.

[0054] Furthermore, since the storage containers themselves can be placed outside the dry room while the stored items are kept in a low-dew-point environment, the space previously used for storage inside the dry room can be effectively utilized. Additionally, the dry room itself can be made smaller, leading to cost reductions.

[0055] Thus, conventionally, for those skilled in the art, it is common sense to store items in a dry room, or in an auto-dry type or gas-purging type storage container or local dry booth to maintain a low dew point environment. A storage container using a honeycomb filter that does not require a power source, as in the present invention, would not have been conceived. However, the inventors diligently investigated a method to maintain a dry environment in the low dew point region for a long period of time without using the power source or gas supply equipment required in the conventional technology, and without power, and with a simple configuration that could not be achieved with standard (desiccant / dehumidifier) ​​types. As a result, the storage container of the present invention was developed by the inventors using a honeycomb filter, which the applicant has used as a core technology for many years, and by devising ways to use the honeycomb filter and the structure of the container.

[0056] The following describes an embodiment 1 of the present invention, in which electrode materials and coated rolls are temporarily stored as storage items in the manufacturing process of lithium-ion batteries. For example, electrode materials are usually stored in a dry room either as they are or in storage containers with low airtightness to prevent reaction with moisture. The dew point required for storage is, for example, -30°C DP or lower.

[0057] Figure 6 shows the change in the dew point temperature inside the storage container of the present invention when a honeycomb filter is installed in the container and the arrangement pattern of the filter is changed. The storage container was left standing in a room with general air conditioning. In arrangement pattern 1, the honeycomb filter was installed on the bottom surface of the storage container 1, and in arrangement pattern 2, the honeycomb filter was installed so as to surround the opening near the door. The honeycomb filter was installed in a heated and dried state. Immediately after the start of storage, the dew point inside the container rose but then quickly fell, and then rose slowly thereafter. In both arrangement patterns, the dew point was maintained at -30°C DP or lower until 130 to 150 hours had elapsed.

[0058] Although the dew point temperature inside the storage container tended to gradually rise due to the intrusion of surrounding moisture, it became possible to store the product outside the dry room for extended periods by replacing the honeycomb filter with a new, dry one before the dew point inside the container exceeded -30°C DP. The timing of replacement can also be adjusted depending on the size, number, and cell size of the honeycomb filter and honeycomb elements, the type and amount of adsorbent, and the airtightness of the storage container.

[0059] If the electrode material contains a sulfide-based electrolyte, hydrogen sulfide will be generated if the ambient humidity is not kept low. When such electrode material is stored in the storage container of the present invention, the inside of the container is kept at a low dew point, so the generation of harmful substances such as hydrogen sulfide from the electrode material can be prevented. Even if hydrogen sulfide is generated during storage, by selecting an appropriate adsorbent, the harmful gas can be adsorbed along with moisture, thereby reducing the impact of harmful gases when removing the stored product from the storage container.

[0060] In the manufacturing process of lithium-ion batteries, for example, the electrode manufacturing process includes steps such as weighing and mixing, coating, roll pressing, and slitting. When each process is separate, movement between processes and storage of materials and work-in-progress are necessary. If all processes are completed within a dry room, then movement and storage within the dry room are sufficient. However, if the processes are separated into different dry rooms, for example, materials and work-in-progress must be moved and stored in the external environment outside the dry room. In such cases, the storage container of the present invention can be used to store materials that require storage in a low dew point environment, and the entire storage container can be moved to the next process for use. Furthermore, materials are usually intended to be stored in environments outside the dry room, resulting in short shelf lives and a large amount of expired waste. By using the storage container of the present invention even in environments outside the dry room, the shelf life of materials can be extended, waste can be reduced, and battery manufacturing costs can be lowered by effectively using materials. Because the storage container of the present invention allows storage outside the dry room, the dry environment required for storage space is no longer necessary, the dry room itself can be made smaller for each process, and power consumption and running costs can be reduced. Furthermore, it allows for more effective use of the storage space that was previously required for storage.

[0061] The storage container of the present invention can be used for storing various items, not just in the manufacturing process of lithium-ion batteries. For example, it is suitable for long-term storage in a low dew point environment for chemical raw materials and powdered pharmaceuticals, surface mount components for ICs and LEDs used in the mounting process of electronic components and semiconductors, printed circuit boards, flexible circuit boards, etc., battery-related components and materials (active materials, binders, electrolytes, etc.) such as lithium-ion batteries, all-solid-state batteries, and capacitors, organic EL-related components, metal powder materials for 3D printers, and reticles, lenses, wafers, etc. used in semiconductor manufacturing. It can also be used as a substitute for commercially available dry boxes and desiccators.

[0062] As a variation of the storage container of the present invention, functions and accessories can be added as needed. By providing doors on the front and rear of the storage container, it is possible to load and unload stored items from both sides, which is convenient for handing over items between processes, saving workspace and effectively shortening the time required for transportation and loading / unloading. The storage container is not limited to rectangular prisms such as cubes or cuboids, but may also be other rectangular prisms or cylinders. Casters can be attached to the bottom of the storage container to make it a wagon type. In this case, a handle may be attached to the main body. Shelves may be provided in the storage container. The shelves may be removable by inserting them, or they may be moved in and out by sliding rails. Multiple doors may be provided, and several doors may be connected to be used as a single opening and closing door. The storage containers may be made stackable. In this case, connecting fittings may be used to fix the stacked storage containers so that they do not shift. A forklift opening may be provided so that it can be transported by forklift. For stored items that are sensitive to light, light-shielding materials may be used for the main body, doors, etc.

[0063] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. Modifications can be combined as appropriate. Furthermore, modifications and the matters described in the embodiment can also be combined as appropriate.

[0064] 1. Storage container 2. Door 3. Main body 4. Hinge 5. Magnetic gasket 6. Magnetic metal plate 7. Honeycomb filter 8. Magnet 9. Honeycomb element 10. Cartridge (storage section)

Claims

1. An airtight storage container having a door and a body, characterized in that a low dew point environment is maintained inside the storage container by arranging a honeycomb filter carrying an adsorbent.

2. The storage container according to claim 1, characterized in that the dew point temperature inside the storage container is adjusted by changing at least one of the following: the size, number, or cell size of the honeycomb filter and / or the plurality of honeycomb elements constituting the honeycomb filter, or the type or amount of adsorbent.

3. The storage container according to claim 1, characterized in that the honeycomb filter is configured to be replaceable.

4. The storage container according to claim 3, characterized in that the honeycomb filter is housed in a housing section, and the housing section is detachably attached to the storage container.

5. The storage container according to claim 3, characterized in that the honeycomb filter is kept separately from the storage container in a state that has been dried and regenerated in advance.

6. The storage container according to claim 1, characterized in that the door is a magnetic gasket door.

7. The storage container according to any one of claims 1 to 6, characterized in that the storage container is provided with a thermometer, hygrometer and / or dew point meter, and the temperature, humidity and / or dew point inside the storage container are controlled.

8. A storage method characterized by maintaining a low dew point environment inside an airtight storage container having a door and a body, by placing a honeycomb filter carrying an adsorbent material inside the storage container.

9. The storage method according to claim 8, characterized in that the low dew point environment is maintained by replacing the honeycomb filter.

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