Transport container for power storage device and method for transporting power storage device using the same

Abstract

To provide a transport container for a power storage device that can reduce the risk of fire spreading to the outside of the container in the event of an abnormality such as damage to the power storage device or a high temperature environment when transporting or moving the power storage device or multiple power storage devices wrapped around it.SOLUTION: A transport container for a power storage device includes a transport container body that houses the power storage device, and a mesh bag or a cage body that houses a pellet-like or bead-like molded body containing an acrylic polymer and that is placed in the gap between the transport container body and the power storage device.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a transport container for packaging and transporting electricity storage devices such as lithium ion batteries, lithium ion capacitors, and electric double layer capacitors, and a method for transporting electricity storage devices using the same, and in particular to a transport container for electricity storage devices that can reduce the risk of fire spreading outside the container even if the electricity storage device catches fire when it is damaged or in an abnormal situation such as a high-temperature environment, and a method for transporting electricity storage devices using the same. [Background technology]

[0002] In recent years, electricity storage devices such as secondary batteries, lithium ion capacitors, and electric double layer capacitors, each of which has an electricity storage device using a non-aqueous electrolyte housed in a casing, have been used as power sources for high-output portable devices, electric vehicles, and the like.

[0003] When transporting or moving such energy storage devices in containers, they are usually transported or moved at a low state of charge (SOC) (for example, below 30%). However, there is a risk of fire or explosion even when the state of charge is low due to a short circuit caused by an external factor or being left in a high-temperature environment.

[0004] As a technique for preventing ignition of such electricity storage devices, for example, a method has been proposed in which gas generated inside a lithium ion battery is absorbed by a flammable gas absorbent material to prevent the battery from exploding (Patent Documents 1 and 2).

[0005] Meanwhile, a method has been proposed in which a fire extinguishing agent is placed inside a lithium-ion battery to lower the temperature of the gas released to the outside when the safety valve opens due to an increase in internal pressure caused by gas generation inside the battery (Patent Document 3).Furthermore, a method has been proposed in which a porous material with a non-flammable gas, aqueous solvent, or non-flammable solvent adsorbed in the pores and on the surface is placed inside the lithium-ion battery to prevent fires caused by gas generated from the lithium-ion battery (Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-155790 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-077549 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-287488 [Patent Document 4] Japanese Patent Application Laid-Open No. 2013-187089 Summary of the Invention [Problem to be solved by the invention]

[0007] However, because a large amount of gas is instantaneously generated when an electrical abnormality or thermal runaway occurs in an electricity storage device, the method of disposing a gas adsorbent in the electricity storage device as described in Patent Documents 1 and 2 has the problem that the amount and speed of gas adsorption by the gas adsorbent are insufficient for the limited space of an electricity storage device, and gas emission from the electricity storage device cannot be completely suppressed. Also, as described in Patent Documents 3 and 4, methods of disposing a fire extinguishing agent to lower the temperature inside a lithium ion battery or disposing a material that adsorbs non-flammable gas or an aqueous solvent or non-flammable solvent in the pores and surface of a porous material in the electricity storage device have the problem that if the gas adsorption amount is insufficient, the effect is not fully exerted and gas emission cannot be completely suppressed.

[0008] Due to these problems, the technologies described in Patent Documents 1 to 4 were not sufficiently effective in preventing short circuits caused by external factors when transporting or moving the electricity storage device in a container, or in preventing fires or explosions when the device is left in a high-temperature environment, thereby preventing the spread of fire to the external environment.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an electricity storage device transport container that can reduce the risk of fire spreading to the outside of the container in the event of an abnormality such as damage to the electricity storage device or a high temperature environment when transporting or moving an electricity storage device or multiple electricity storage devices wrapped around it, and a transportation method using this transport container. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention first provides a transport container for an electricity storage device, comprising a transport container main body that houses an electricity storage device, and a mesh bag or cage that houses pellet- or bead-like molded bodies containing an acrylic polymer and that are placed in the gap between the transport container main body and the electricity storage device (Invention 1). In particular, it is preferable that the pellet- or bead-like molded bodies containing the acrylic polymer have a particle size of 1 mm to 10 mm (Invention 2). Furthermore, it is preferable that the mesh diameter of the mesh bag or cage that houses the pellet- or bead-like molded bodies containing the acrylic polymer is 0.5 mm to 7 mm, which is smaller than the smallest particle size of the molded bodies containing the acrylic polymer (Invention 3).

[0011] According to these inventions (Inventions 1 to 3), by disposing a molded body containing an acrylic polymer in the space between the electricity storage device and the electricity storage device transport container, the risk of fire spreading outside the transport container in the event of an abnormality such as damage to the electricity storage device or a high-temperature environment can be reduced. In this case, the molded body containing the acrylic polymer is in the form of pellets or beads and is housed in a mesh bag or cage that is breathable but impermeable to the molded body. Therefore, when gas or ejected material ejected in the event of an abnormality in the electricity storage device passes through the mesh bag or cage, it comes into contact with the acrylic polymer multiple times. Furthermore, the filtering effect of the pellet- or bead-shaped molded body reduces the amount of ejected material released outside the transport container, thereby efficiently and significantly reducing the risk of fire. Furthermore, by disposing the molded body above and below the electricity storage device to be transported as a buffer or cushioning material, it can be made easier to handle. In particular, by making the pellet- or bead-shaped molded bodies containing an acrylic polymer have a particle size of 1 mm to 10 mm and the mesh diameter of the mesh bag or cage body 0.5 mm to 3 mm, which is smaller than the minimum particle size of the molded bodies containing an acrylic polymer, the pellet- or bead-shaped molded bodies containing an acrylic polymer will not leak out of the mesh bag or cage body.

[0012] In the above invention (invention 3), it is preferable that the electricity storage device uses a non-aqueous electrolyte (invention 4).

[0013] According to this invention (Invention 4), when an abnormality occurs in the electricity storage device, it is possible to preferably prevent the fire from spreading to the outside of the transport container.

[0014] In the above invention (Invention 3), the molded article containing the acrylic polymer preferably contains 10% by weight or more of the acrylic polymer as a whole (Invention 5).

[0015] According to this invention (Invention 5), when an abnormality occurs in the electricity storage device, it is possible to preferably exert the effect of preventing the spread of fire to the outside of the transport container.

[0016] In the above invention (Invention 3), the acrylic polymer is preferably a homopolymer or copolymer synthesized using one or more types of (meth)acrylic acid alkyl esters as monomers, polyacrylonitrile synthesized using acrylonitrile as a monomer, or a copolymer of a (meth)acrylic acid alkyl ester or acrylonitrile with one or more other monomers (Invention 6).

[0017] According to this invention (Invention 6), it is possible to suitably reduce the risk of fire spreading to the outside of the transport container in the event of an abnormality such as damage to the electricity storage device or a high temperature environment.

[0018] In the above inventions (Inventions 1 to 6), a plurality of the electricity storage devices may be stacked (Invention 7).

[0019] In the above invention (Invention 7), in an electricity storage device stack in which multiple electricity storage devices are stacked, if there is an abnormality in one electricity storage device, even if flammable gas is ejected from the electricity storage device and flows into the space of the transport container, the material of the molded body containing an acrylic polymer can affect the flammable gas, thereby significantly reducing the risk of the fire spreading outside the transport container, making this invention particularly suitable for application to electricity storage device stacks.

[0020] Secondly, the present invention provides a method for transporting an electricity storage device, in which an electricity storage device is housed in a transportation container for an electricity storage device according to any one of claims 1 to 7 and transported (invention 8).

[0021] According to this invention (Invention 8), by placing a mesh bag or cage containing pellet-shaped or bead-shaped molded bodies containing an acrylic polymer in the space between the electricity storage device and the electricity storage device transport container body, the electricity storage device can be transported with a reduced risk of fire spreading outside the transport container in the event of an abnormality such as damage to the electricity storage device or a high temperature environment. [Effects of the Invention]

[0022] The electricity storage device transport container of the present invention has a mesh bag or cage containing pellet- or bead-like molded bodies containing an acrylic polymer disposed in the gap between the transport container body that houses the electricity storage device and the electricity storage device, so that the acrylic polymer has an effect on high-temperature ejected material and ejected gas that are released from the electricity storage device due to a short circuit, etc., thereby significantly reducing the risk of fire in the electricity storage device transport container. In this case, because the pellet- or bead-like molded bodies containing the acrylic polymer are contained in the mesh bag or cage, they can be disposed above and below the electricity storage device to be transported as buffering or cushioning material, making them easy to handle. DETAILED DESCRIPTION OF THE INVENTION

[0023] The electricity storage device transport container of the present invention will be described in detail based on the following embodiments.

[0024] [Electricity storage device transport container] The energy storage device transport container of this embodiment has a structure in which a mesh bag or cage containing a pellet-shaped or bead-shaped molded body containing an acrylic polymer is placed in the gap between the transport container body that contains the energy storage device and the energy storage device.

[0025] (Electricity storage device) In this embodiment, the power storage device is not particularly limited, and either a primary battery or a secondary battery can be used, but a secondary battery is preferred. The type of secondary battery is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these, those using nonaqueous electrolytes are preferred. Among these secondary batteries, the battery material of the present invention is preferably applicable to lithium ion batteries, lithium ion polymer batteries, lithium ion capacitors, all-solid-state batteries, and the like.

[0026] The above-described electricity storage device may be in the form of an electricity storage device stack in which a plurality of devices are stacked.

[0027] (Electricity storage device transport container body) In this embodiment, the transport container body is not particularly limited as long as it can encase the above-mentioned electricity storage device (electricity storage device stack) with a gap therebetween, and can be made of various materials such as synthetic resin or metal. This transport container body is generally shaped like a rectangular box, but is not limited to this. This transport container body is preferably provided with a release valve or release hole so that, in the event of an abnormality in the electricity storage device, ejected gas or ejected material released from the electricity storage device can be released outside the transport container.

[0028] (fire-preventive material) In this embodiment, a molded body containing an acrylic polymer is disposed as an ignition prevention material in the gap between the electricity storage device and the transport container body.

[0029] Examples of the acrylic polymer include acrylic polymers (homopolymers or copolymers) synthesized using one or more (meth)acrylic acid alkyl esters as monomers. Also included are polyacrylonitriles synthesized using acrylonitrile as a monomer. Furthermore, examples include copolymers of these (meth)acrylic acid alkyl esters or acrylonitrile with one or more other monomers.

[0030] Specific examples of the (meth)acrylic acid alkyl ester include, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, sec-butyl methacrylate, and isobutyl methacrylate.

[0031] Examples of other monomers copolymerizable with the monomers used in the acrylic polymer include, but are not limited to, other (meth)acrylic acid alkyl esters, acrylonitrile, acrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, and styrene. The amount of these other monomers is preferably less than 90% by weight, particularly about 40% by weight or less, relative to 100% by weight of the total of the monomers used in the acrylic polymer and the other monomers. If the amount of the other monomers is too high, the effect of reducing the risk of fire in the electricity storage device transport container will be insufficient.

[0032] The acrylic polymer may further contain various commonly used additives, provided that the effects of the present invention are not impaired. Examples of additives include crosslinked rubber particles, ultraviolet absorbers, slip agents, antioxidants, release agents, antistatic agents, and flame retardants. The surface of the acrylic polymer may be coated with a material to enhance functionality, provided that the effects of the present invention are not impaired.

[0033] The above-mentioned fire prevention materials may be used alone or in combination of two or more materials.

[0034] Furthermore, these ignition prevention materials can also be used by adding materials that have a cooling effect through heat transfer and absorption against ejected materials and gases from the electricity storage device, an effect of suppressing combustion radical reactions, and an extinguishing effect that makes flames on the surface of the adsorbent unstable.

[0035] (Ignition prevention element) In this embodiment, the molded body of the fire-preventing material placed in the gap between the transport container housing the electricity storage device and the electricity storage device is in the form of pellets or beads. The particle size of the pellet- or bead-shaped molded body is preferably 1 mm to 10 mm, particularly 2 mm to 5 mm. A particle size of less than 1 mm is too small, reducing the breathability of the material housed in the mesh bag or cage described below and resulting in an insufficient reduction in the risk of fire in the electricity storage device transport container. On the other hand, a particle size of more than 10 mm results in an excessively small surface area of ​​the molded body of the fire-preventing material per unit weight, resulting in an insufficient reduction in the risk of fire spreading outside the transport container in the event of an abnormality such as damage to the electricity storage device or a high-temperature environment, as well as an insufficient cushioning effect. Note that, in this specification, the particle size of the pellet- or bead-shaped molded body is assumed to be within a range of ±20%, preferably ±10%, of the median.

[0036] The pellet- or bead-shaped molded products are then housed in a mesh bag or cage and used as a fire prevention element. The mesh diameter of the mesh bag or cage is smaller than the minimum particle size (-20% of the median) of the pellet- or bead-shaped molded products containing the acrylic polymer, and is preferably 0.5 mm to 7 mm, particularly 0.5 mm to 5 mm, and even more preferably 1 mm to 3 mm. The mesh bag or cage that houses the pellet- or bead-shaped molded products is preferably soft or flexible, but may also be rigid. Materials such as synthetic resin, elastomer, and metal can be used, with flexible bags made of synthetic resin being preferred. In the case of a rigid cage, it should be smaller than the main body of the electricity storage device transport container.

[0037] [Transportation method for electrical devices] The transport container for an electric storage device comprising the electric storage device transport container main body and the ignition prevention material element as described above may be transported by first placing a mesh bag or cage containing a molded body of ignition prevention material in the transport container main body, then placing an electric storage device with a state of charge (SOC) of, for example, about 30%, and then covering it from above with a mesh bag or cage containing a molded body of ignition prevention material, and then sealing the transport container. Alternatively, the electric storage device may be placed in the transport container main body, and then a mesh bag or cage containing a molded body of ignition prevention material may be placed in the gap, and the transport container may be sealed and transported.

[0038] By storing and transporting an electricity storage device in such a transport container of this embodiment, even if the electricity storage device were to ignite due to a short circuit caused by an external factor or if it were left in a high-temperature environment, the provision of a molded body made of an ignition-preventing material prevents the spread of fire within the transport container even if a short circuit caused by an external factor occurs when the electricity storage device is placed in the container for transportation or movement, or if it were to ignite or explode if it were left in a high-temperature environment, thereby reducing the risk of fire spreading outside the transport container.

[0039] The transport container for an electricity storage device of the present invention has been described above. However, the present invention is not particularly limited in size or shape of the electricity storage device (electricity storage device stack), as long as a mesh bag or cage containing a molded body of a fire-preventing material is placed in the gap between the electricity storage device (electricity storage device stack) and the transport container body. Therefore, it is applicable to electricity storage devices for a wide range of uses, from smartphones to automobile-mounted electricity storage devices (electricity storage device stacks). It is particularly suitable as a transport container for relatively large electricity storage devices (electricity storage device stacks) for automobiles. [Example]

[0040] The present invention will be described in more detail based on the following specific examples, but the present invention is not limited to the following examples.

[0041] [Nail penetration test] (Comparative Example 1) A PP resin container (inner diameter: 80 mm wide x 105 mm long x 34 mm deep, resin thickness: 2 mm; the electrode side of an aluminum-laminated lithium-ion battery was placed on the 80 mm side of the PP resin container, and five 10 mm diameter holes were drilled on the 80 mm side of the PP resin container, leaving the top open) was prepared as a transport container for an energy storage device. A fully charged 1500 mAh aluminum-laminated lithium-ion battery (35 mm wide x 75 mm long) with a positive electrode ternary system was placed inside the PP resin container, and a 4 mm thick PP resin plate was placed over the battery and sealed tightly with heat-resistant tape around the edges of the lid. This configuration ensured that any ejection of material from the lithium-ion battery due to overcharge would be released only through the five holes.

[0042] A PP resin container intended for transport (inner diameter: 98 mm wide x 148 mm long x 48 mm deep, resin thickness: 2 mm, open-topped with five 10 mm diameter holes drilled on the 98 mm wide side (a container with holes drilled on the opposite side to the holes on the PP resin container intended for the above-mentioned energy storage device container)) was placed on the outside of this PP resin container intended for the energy storage device container, and a 4 mm thick PP resin plate was used to cover it.The edges of the lid were sealed using heat-resistant tape to ensure there were no gaps, and the battery ejection during the nail penetration test was to be released only through the five drilled holes, completing the energy storage device transport container.

[0043] When a nail penetration test was conducted on this electricity storage device transport container, the lithium-ion battery was destroyed and a violent fire was confirmed on the outside of the transport container.

[0044] Example 1 The energy storage device transport container used in Comparative Example 1 was used as the transport container body, and the gap between this transport container body and the energy storage device container was filled with 40 g of pellet-shaped molded bodies (particle size 2 mm to 5 mm) of an acrylic polymer (94% or more polymer mainly composed of polymethyl methacrylate, 5% or less additives) contained in a flexible synthetic resin bag with a mesh diameter of 1 mm to form an energy storage device transport container.

[0045] When this electricity storage device transport container was subjected to a nail penetration test under the same conditions as in Comparative Example 1, the lithium ion battery was destroyed, but no ignition was observed outside the transport container.

Claims

1. A transport container for an electricity storage device, comprising: a transport container body that houses an electricity storage device; and a mesh bag or cage body that houses a pellet-like or bead-like molded body containing an acrylic polymer, which is placed in the gap between the transport container body and the electricity storage device.

2. 2. The electricity storage device transport container according to claim 1, wherein the pellet-shaped or bead-shaped molded body containing the acrylic polymer has a particle size of 1 mm to 10 mm.

3. 3. The electricity storage device transport container according to claim 2, wherein a mesh diameter of a mesh bag or cage for containing the pellet-shaped or bead-shaped molded body containing the acrylic polymer is 0.5 mm to 7 mm, and is smaller than the minimum particle size of the molded body containing the acrylic polymer.

4. The electricity storage device transport container according to claim 3 , wherein the electricity storage device uses a non-aqueous electrolyte.

5. The electricity storage device transport container according to claim 3 , wherein the molded article containing an acrylic polymer contains 10% by weight or more of the acrylic polymer as a whole.

6. The energy storage device transport container according to claim 3, wherein the acrylic polymer is a homopolymer or copolymer synthesized using one or more (meth)acrylic acid alkyl esters as monomers, polyacrylonitrile synthesized using acrylonitrile as a monomer, or a copolymer of a (meth)acrylic acid alkyl ester or acrylonitrile with one or more other monomers.

7. The electricity storage device transport container according to any one of claims 1 to 6, wherein a plurality of the electricity storage devices are stacked.

8. A method for transporting an electricity storage device, comprising storing the electricity storage device in the electricity storage device transport container according to any one of claims 1 to 7 and transporting the electricity storage device.