Battery pack having a fire extinguishing film containing microcapsules for fire extinguishing

Abstract

The present invention relates to a battery pack, and more particularly to a battery pack having a fire extinguishing film containing fire extinguishing microcapsules that can be conveniently disposed in a narrow space formed when arranging a plurality of cylindrical secondary batteries, without having any influence on battery performance or arrangement, and capable of actively extinguishing in the initial stage of abnormal battery heating or fire occurrence. To this end, the present invention includes: a cylindrical secondary battery (10) having a positive electrode (11) protruding from one surface and a negative electrode (12) formed flat on the other side surface; a housing (20) for accommodating a plurality of the cylindrical secondary batteries (10) in the horizontal and vertical directions and forming a predetermined space; and a fire extinguishing film (30) containing fire extinguishing microcapsules and disposed in a predetermined space within the housing (20) in the form of a flexible film.

Description

Technical Field

[0001] The present invention relates to a battery pack, and more particularly to a battery pack having a fire extinguishing film containing fire extinguishing microcapsules, which can be conveniently disposed in a narrow space formed when arranging a plurality of cylindrical secondary batteries, without any influence on battery performance or arrangement, and can actively extinguish fire at the initial stage of abnormal heating or fire occurrence of the battery. Background Art

[0002] Recently, with the commercialization of high-power secondary batteries using non-aqueous electrolytes with high energy density, research and development in related fields are actively underway, aiming to be used not only for portable devices but also for medium and large-sized devices such as electric vehicles that require large power.

[0003] Such secondary batteries not only have the advantage of significantly reducing the use of fossil fuels but also do not produce any by-products generated by using energy at all, and thus are attracting much attention as a new type of environmentally friendly and energy-efficient power source.

[0004] Currently, the types of secondary batteries widely used include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. In order to be applied to devices such as electric vehicles that require a high output voltage, a plurality of secondary batteries are connected to form a battery pack.

[0005] In the above battery pack, cylindrical secondary batteries are mainly used as battery cells. When the voltage of the cylindrical secondary batteries in such a battery pack rapidly rises due to short circuit or over-discharge of the electrode part, the battery may catch fire. When overcharged, as the positive and negative electrodes are heated and become unstable according to the charging state, a fire may also occur due to a rapid heat generation reaction.

[0006] However, considering the structure of the battery pack where secondary batteries are densely arranged and there is almost no unused space, it is not only very difficult to set up an additional protection circuit or fire extinguishing unit in the battery pack itself, but also does not conform to the current trend of miniaturization and cost reduction of the battery pack. Therefore, an effective solution is needed that can be conveniently disposed in a narrow space within the battery pack to actively respond to the abnormal heating or fire occurrence of the secondary battery at the initial stage.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Korean Patent Publication No. 10-2009-0026648

[0010] Patent Document 2: Korean Patent Publication No. 10-2015-0003779 Summary of the Invention

[0011] Technical problem

[0012] The present invention aims to solve the above technical problems in the prior art. Its purpose is to provide a battery pack with a fire-extinguishing film containing fire-extinguishing microcapsules, which can be conveniently arranged in a narrow space formed when arranging multiple cylindrical secondary batteries, without having any impact on battery performance or arrangement, and can actively extinguish fires at the initial stage of abnormal battery heating or fire occurrence.

[0013] Technical solution

[0014] To achieve the above object, the present invention includes: a cylindrical secondary battery, with a positive electrode protruding from one side surface and a negative electrode formed flat on the other side surface; a housing for accommodating a plurality of the cylindrical secondary batteries in the transverse and longitudinal directions and forming a specified space; and a fire-extinguishing film containing fire-extinguishing microcapsules and arranged in a specified space inside the housing in the form of a flexible film.

[0015] Among them, the fire-extinguishing film is formed by fire-extinguishing microcapsules and a polymer composition. The fire-extinguishing microcapsules consist of a core that is a liquid phase at normal temperature and changes to a gas phase at a temperature of 30 to 300 °C as a fire extinguishing agent, and a shell that contains a polymer resin, a precipitant, and a coagulant and surrounds the core with a thickness of 50 to 2000 nm. The polymer composition is used to disperse the fire-extinguishing microcapsules and can be formed into a film shape.

[0016] In addition, the fire-extinguishing film is in the shape of an O-ring so as to be placed on one side surface in a manner of fitting over the positive electrode of the cylindrical secondary battery and arranged in the space between the positive electrode and the one side surface, or is formed with a first through hole for simultaneously passing through the positive electrodes of a plurality of cylindrical secondary batteries located inside the housing. And the fire-extinguishing film covers the space between a plurality of positive electrodes and the one side surface and the space between the cylindrical secondary batteries, or is formed with a second through hole for simultaneously exposing the negative electrodes of a plurality of cylindrical secondary batteries located inside the housing to the outside. And the fire-extinguishing film covers the space between the cylindrical secondary batteries.

[0017] Alternatively, the fire-extinguishing film is arranged in the longitudinal space between a plurality of cylindrical secondary batteries in the form of a partition, or is arranged in a lattice shape in the transverse and longitudinal directions in the form of a partition, or is configured to respectively wind around the outer peripheral edge in the longitudinal direction of the cylindrical secondary battery.

[0018] On the other hand, the polymer composition is one or more selected from polypropylene, (meth)acrylic acid polymers, (meth)acrylic acid monomers, 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, cellulose, bisphenol A polycarbonate, (meth)epoxy polymers, epoxy monomers, poly(ethylene-co-propylene-co-5-methylene-2-norbornene), 4,4'-isopropylidenediphenol, vinyl chloride, vinylidene chloride, tetrafluoroethylene, vinyl C1-C10 alkylates (CH2CH-OC(O)R, where R is a C1-C10 alkyl group), vinyl C1-C10 alkyl ethers, vinyl pyrrolidone, vinyl carbazole, acrylic acid, acrylonitrile, acrylamide, acrylic C1-C10 alkyl esters, methacrylic acid, methacrylonitrile, methacrylamide, methacrylic C1-C10 alkyl esters, and silicone rubbers.

[0019] In addition, the precipitating agent contains one or more selected from potassium acetate, sodium citrate, sodium chloride, ammonium chloride, sodium iodide, potassium iodide, copper sulfate, and sodium thiocyanate.

[0020] In addition, the coagulant contains one or more selected from zinc hydroxide and iron hydroxide.

[0021] Furthermore, the polymer composition contains a heat-insulating material component in powder form.

[0022] Advantageous Effects

[0023] The battery pack of the present invention having a fire-extinguishing film containing fire-extinguishing microcapsules can achieve the following effects.

[0024] 1. The fire-extinguishing film with a fire-extinguishing function can be conveniently arranged in a narrow space inside the battery pack, for example, the space between multiple cylindrical secondary batteries, the space between the outer shell and the secondary battery, etc.

[0025] 2. There is no need to change the arrangement of the cylindrical secondary batteries or the existing outer shell structure for arranging the fire-extinguishing film. Therefore, it can also be immediately applied to off-the-shelf products.

[0026] 3. React immediately at the initial stage of abnormal heating or fire occurrence of the cylindrical secondary batteries in the battery pack to reduce the heating temperature or extinguish the fire.

[0027] 4. There is no need to prepare an additional space. By directly applying the relatively inexpensive fire-extinguishing film to the battery pack, the problems of heating and fire can be solved. Therefore, a battery pack that is economical, stable, and can be miniaturized and light-weight can be manufactured. Description of the Drawings

[0028] Figure 1 FIG. 0 is a diagram schematically showing a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0029] Figure 2 FIG. 1 is a diagram showing a state of a fire extinguishing film to which an O-ring structure is applied in a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0030] Figure 3 FIG. 2 is a diagram showing a state of a fire extinguishing film to which a positive electrode covering sheet structure is applied in a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0031] Figure 4 FIG. 3 is a diagram showing a state of a fire extinguishing film to which a negative electrode covering sheet structure is applied in a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0032] Figure 5 FIG. 4 is a diagram showing a state of a fire extinguishing film to which a separator structure is applied in a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0033] Figure 6 FIG. 5 is a diagram showing a state of a fire extinguishing film to which a battery winding structure is applied in a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules. DETAILED DESCRIPTION

[0034] The terms and words used in this specification and the claims should not be construed as limited to the conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the terms to explain his own invention by the optimal method, they should be construed as meanings and concepts conforming to the technical idea of the present invention.

[0035] Therefore, the embodiments described in this specification and the features shown in the drawings are only the most preferred embodiment of the present invention and do not represent all the technical ideas of the present invention. Therefore, at the time of filing this application, there may be various equivalent inventions and multiple variations that can replace them.

[0036] Hereinafter, a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules will be described with reference to the drawings.

[0037] Figure 1 FIG. 0 is a diagram schematically showing a battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules.

[0038] The present invention basically includes a cylindrical secondary battery 10, a housing 20, and a fire extinguishing film 30.

[0039] Specifically, the present invention includes: a cylindrical secondary battery 10, with a positive electrode 11 protruding from one side surface and a negative electrode 12 formed flat on the other side surface; a housing 20 for accommodating a plurality of cylindrical secondary batteries 10 in the transverse and longitudinal directions and forming a specified space; and a fire extinguishing film 30 containing fire extinguishing microcapsules and disposed in a specified space within the housing 20 in the form of a flexible film.

[0040] The cylindrical secondary battery 10 is used to convert external electrical energy into chemical energy and store it, and generate electricity when needed, and can be charged multiple times. Commonly used secondary batteries include lead-acid batteries, nickel-cadmium batteries (NiCd), nickel-metal hydride batteries (Ni-MH), lithium-ion batteries (Li-ion), lithium-ion polymer batteries (Li-ion polymer), etc. As is well known in the art, the main body is cylindrical, and has a structure with a protruding positive electrode at the center of one side surface and a flat-shaped negative electrode on the other side surface, and can be classified into 18650 (industry standard), 21700, etc. according to size.

[0041] The housing 20 accommodates a plurality of cylindrical secondary batteries 10 to form a battery pack. Although not shown in the drawings, it may include bus bars that are respectively in electrical contact with the positive electrode 11 and the negative electrode 12 of the cylindrical secondary battery 10, and terminals for outputting the power transmitted through the bus bars to the outside. It may also have a structure with holes formed only for making the bus bars or terminals located outside contact the cylindrical secondary battery 10, or a separable structure in which the cylindrical secondary battery 10 is disposed at the lower part and then combined with the upper part. It is preferably interpreted as being able to undergo various other shape deformations to output the power supplied by the plurality of cylindrical secondary batteries 10 to the outside.

[0042] The fire extinguishing film 30 is formed into a film shape after dispersing fire extinguishing microcapsules in a polymer composition, and then disposed in the space formed by the cylindrical secondary battery 10 and the housing 20. Among them, the fire extinguishing microcapsules are composed of a core that is a fire extinguishing agent and is in a liquid phase at normal temperature and changes to a gas phase at a temperature of 30 to 300 °C, and a shell that contains a polymer resin / precipitant / coagulant and surrounds the core with a thickness of 50 to 2000 nm. This fire extinguishing agent can use 1,1,1,2,2-pent (1,1,1,2,2-Pent).

[0043] Among them, the fire extinguishing microcapsules have a core-shell shape with an outer shell surrounding an inner core. The core is a fire extinguishing agent, and the shell is formed of a polymer resin. The fire extinguishing agent accounts for 80% to 97% by weight of the fire extinguishing microcapsules.

[0044] This fire extinguishing agent can use 1,1,1,2,2-pentafluoroethane (entafluoroethane; CF3CF2H; HFC-125), 1,1,1,2,3,3,3-heptafluoropropane (1,1,1,2,3,3,3-Heptafluoropropane; CF3CHFCF3), chlorotetrafluoroethane (Chlorotetrafluoroethane; CHClFCF3), fluorochemical ketone compounds, dodecafluoro-2-methyl-3-pentanone (dodecafluoro-2-methylpentan-3-one; FK-5-1-12; CF3CF2C(O)CF(CF3)2)), 1-chloro-1,2,2,2-tetrafluoroethane (1-chloro-1,2,2,2-tetrafluoroethane; C2HClF4), 2-chloro-1,1,1,2-tetrafluoroethane (2-chloro-1,1,1,2-tetrafluoroethane; CHClFCF3;HCFC-124), perfluorocyclohexanone (decafluorocyclohexanone), CF3CF2C(O)CF(CF3)2 (1,1,1,2,4,4,5,5,5-nonafluoro-2-trifluoromethyl-3-pentanone), (CF3)2CFC(O)CF(CF3)2 (1,1,1,2,4,5,5,5-octafluoro-2,4-bis(trifluoromethyl)-3-pentanone), CF3CF2C(O)CF2CF2CF3, CF3C(O)CF(CF3)2, 1,1,1,3,3,4,4,5,5,6,6,7,7,8,8,8-hexadecafluoro-2-octanone (CF3CF2CF2CF2CF2CF2C(O)CF3), 1,1,1,3,4,4,4-heptafluoro-3-trifluoromethyl-2-butanone (CF3C(O)CF(CF3)2), 1,1,1,2,4,4,5,5-octafluoro-2-trifluoromethyl-3-pentanone (HCF2CF2C(O)CF(CF3)2), 1,1,1,2,4,4,5,5,6,6,6-undecafluoro-2-trifluoromethyl-3-hexanone (CF3CF2CF2C(O)CF(CF3)2), 1-chloro-1,1,3,4,4,4-hexafluoro-3-trifluoromethyl-2-butanone ((CF3)2CFC(O)CF2Cl), 1,1,1,2,2,4,4,5,5,6,6,6-dodecafluoro-3-hexanone (CF3CF2C(O)CF2CF2CF3), 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (CF3C(O)CH2C(O)CF3), 1,1,1,2,5,6,6,6-octafluoro-2,5-bis(trifluoromethyl)-3,4-hexanedione ((CF3)2CFC(O)C(O)C(O)CF(CF3)2), 1,1,1,2,2,3,3,5,5,6,6,7,7,7-tetradecafluoro-4-heptanone (CF3CF2CF2C(O)CF2CF2CF3), 1,1,1,3,3,4,4,4-octafluoro-2-butanone (CF3C(O)CF2CF3), 1,1,2,2,4,5,5,5-octafluoro-1-trifluoromethoxy-4-trifluoromethyl-3-pentanone (CF3OCF2CF2C(O)CF(CF3)2), 1,1,1,2,4,4,5,5,6,6,7,7,7-tridecafluoro-2-trifluoromethyl-3-heptanone (CF3CF2CF2CF2C(O)CF(CF3)2), etc.;

[0045] In addition, the fire extinguishing agent can be perfluorobutane (FC-3-1-10), a mixture of hydrochlorofluorocarbons (HCFC-123, HCFC-22, HCFC-124), chlorotetrafluoroethane (HCFC-124), pentafluoroethane (HFC-125), heptafluoropropane (HFC-227ea), trifluoromethane (HFC-23), hexafluoropropane (HFC-236fa), trifluoroiodomethane (FIC-13I1), a non-combustible gas / inert gas mixture (e.g., N2, Ar, CO2), and dodecafluoro-2-methyl-3-pentanone (FK-5-1-12), etc.

[0046] The above-mentioned fire extinguishing agent can play a role in indirectly reducing the surrounding heat energy to suppress the occurrence of a fire or directly extinguishing the fire.

[0047] The shell of the fire extinguishing microcapsule plays a role in surrounding the outside of the fire extinguishing agent to store the fire extinguishing agent in the encapsulated internal space, and ensures weather resistance and airtightness to prevent the fire extinguishing agent from being exposed to the atmosphere under the influence of the external environment at normal temperature.

[0048] This shell softens at 100 - 300 °C regarded as a fire. At the same time, it expands and ruptures along with the phase change of the fire extinguishing agent, thereby spraying the fire extinguishing agent outward. In order to react within the above-mentioned fire temperature range, the thickness is preferably 50 - 2000 nm.

[0049] In addition, the polymer resin used to form the shell can be polyurethane resin, polyurea resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, melamine resin, polystyrene resin, styrene-acrylate copolymer resin, styrene-methacrylate copolymer resin, gelatin or its derivatives, polyvinyl alcohol, phenolic resin, resorcinol formaldehyde resin, etc.

[0050] In addition, when preparing by adding a precipitating agent such as potassium acetate, sodium citrate, sodium chloride, ammonium chloride, sodium iodide, potassium iodide, copper sulfate, and sodium thiocyanate or a coagulant such as aluminum sulfate, zinc hydroxide, iron hydroxide, and iron chloride to the polymer resin, the microcapsule selection rate or the curing speed can be adjusted.

[0051] With the above composition, a large number of fire extinguishing microcapsules do not react (rupture, expose) due to the durability and airtightness of the shell, but react and explode simultaneously at a specific temperature (e.g., above 100 °C), spraying out the vaporized fire extinguishing agent, so that the fire extinguishing agent directly acts on the fire ignition point, blocking the fuel (combustible), oxygen (air), heat (fire source), and the chain reaction with heat (fire source) among the four major conditions for combustion, in order to extinguish high-energy fires.

[0052] The polymer composition may be one or more selected from polypropylene, (meth)acrylic acid polymers, (meth)acrylic acid monomers, 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, cellulose, bisphenol A polycarbonate, (meth)epoxy polymers, epoxy monomers, poly(ethylene-co-propylene-co-5-methylene-2-norbornene), 4,4'-isopropylidenediphenol, vinyl chloride, vinylidene chloride, tetrafluoroethylene, vinyl C1-C10 alkylates (CH2CH-OC(O)R, where R is a C1-C10 alkyl group), vinyl C1-C10 alkyl ethers, vinyl pyrrolidone, vinyl carbazole, acrylic acid, acrylonitrile, acrylamide, C1-C10 alkyl acrylates, methacrylic acid, methacrylonitrile, methacrylamide, C1-C10 alkyl methacrylates, and silicone rubbers.

[0053] Among them, the polymer composition may further contain a monofunctional acrylate of a monohydric alcohol having physical properties of adhering to the surface of a low surface energy. Such an acrylate may be one or more selected from isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, decyl acrylate, dodecyl acrylate, hexyl acrylate, butyl acrylate, octadecyl acrylate, 2-propylheptyl acrylate, etc.

[0054] The fire extinguishing film 30 obtained by mixing the above-mentioned microcapsules for fire extinguishing and the polymer composition is easy to adjust the thickness, and can be manufactured into a non-sticky type or a slightly sticky type according to the selection of the composition. A double-sided tape may be attached to or an adhesive may be coated on one surface of the fire extinguishing film 30 to firmly fix the fire extinguishing film 30 to the cylindrical secondary battery 10 or the outer casing 20.

[0055] The polymer composition may contain a heat insulating material component in powder form, which is used to endow the fire extinguishing film with a heat insulating function to prevent, to the greatest extent, the heat or fire generated in the cylindrical secondary battery 10 from transferring to other batteries. Examples of the heat insulating material component may include glass wool, vermiculite, asbestos, rock wool, perlite, siliceous, aluminous, magnesious, carbonaceous, etc.

[0056] Next, the structure of the fire extinguishing film 30 is applied to the specified space formed by the outer casing 20 and the cylindrical secondary battery 10, and with reference to Figure 1 the part corresponding to A in Figures 2 to 6 which is enlarged and shown, a detailed description thereof will be given.

[0057] 1. O-ring structure (refer to Figure 2 )

[0058] - It has a shape that is arranged on one side surface in a way that fits into the positive electrode 11 of the cylindrical secondary battery 10 and is configured in the space between the positive electrode 11 and the one side surface.

[0059] - The positive electrode 11 penetrates through a through-hole formed in the center, and annular thin film portions are respectively located on one side surface of each secondary battery 10.

[0060] - The fire extinguishing film can be located in the space between a conductive component such as a bus bar on the upper surface of the positive electrode 11 of the cylindrical secondary battery 10 for outputting the power supplied by the secondary battery 10 to the outside and one side surface of the secondary battery 10. Therefore, without ensuring an additional space, a minimum amount of fire extinguishing film can be used to insulate between one side surface of the secondary battery 10 and the conductive component, and at the same time, it can immediately extinguish the fire when the secondary battery 10 generates heat and reaches a specific temperature or higher or a fire occurs.

[0061] 2. Positive electrode covering sheet structure (refer to Figure 3 )

[0062] - A first through-hole 31 is formed for simultaneously passing through the positive electrodes 11 of a plurality of cylindrical secondary batteries 10 located in the housing 20, and it covers the space between the plurality of positive electrodes 11 and one side surface and the space between the cylindrical secondary batteries 10.

[0063] - Different from the O-ring structure arranged one by one for secondary batteries, it can cover a plurality of cylindrical secondary batteries 10 in the form of a sheet for easy construction.

[0064] - Similar to the O-ring structure, it is located in the space between the positive electrode 11 and one side surface to insulate between one side surface of the secondary battery 10 and the conductive component.

[0065] 3. Negative electrode covering sheet structure (refer to Figure 4 )

[0066] - A second through-hole 32 is formed for simultaneously exposing the negative electrodes 12 of a plurality of cylindrical secondary batteries 10 located in the housing 20 to the outside, and it covers the space between the cylindrical secondary batteries 10.

[0067] - Generally, considering that the negative electrode 12 usually has a diameter almost the same as the cylindrical diameter of the battery, the second through-hole 32 formed in the thin film in the shape of a sheet also has a size that can allow the whole battery to pass through. And while the negative electrode 12 is in contact with the conductive component to output the power supplied by the secondary battery 10 to the outside, the whole thin film is located on the bottom surface of the housing to provide a fire extinguishing function when the secondary battery 10 generates heat or a fire occurs.

[0068] 4. Separator structure (refer to Figure 5 )

[0069] - It is disposed in the longitudinal space between multiple cylindrical secondary batteries 10 in the form of a partition.

[0070] - In view of the fact that the fire extinguishing film 30 can be formed with a relatively thin thickness, the film can be arranged in a manner inserted between the secondary batteries 10.

[0071] - At this time, multiple fire extinguishing films 30 are arranged in a grid shape in the transverse and longitudinal directions in the form of partitions so that the film is located in a larger space, thereby maximizing the fire extinguishing performance.

[0072] 5. Battery winding structure (refer to Figure 6 )

[0073] - It is configured to wind around the outer peripheral edge in the longitudinal direction of the cylindrical secondary battery 10 respectively.

[0074] - Each battery is wound with a fire extinguishing film, and the fire extinguishing film itself has adhesiveness. Therefore, it can be easily attached without the need to coat an adhesive on the film additionally.

[0075] The O-ring, positive electrode covering sheet, negative electrode covering sheet, partition, and battery winding structure of the above-mentioned fire extinguishing film can be selectively or comprehensively applied in a suitable manner according to the space of the secondary battery 10 arranged in the housing 20.

[0076] As above, with reference to the drawings, the present invention has been described mainly in a specific shape and direction. However, the present invention can be variously deformed and changed by those skilled in the art, and such deformations and changes should be construed as belonging to the scope of the rights of the present invention.

[0077] Industrial Applicability

[0078] The battery pack of the present invention having a fire extinguishing film containing fire extinguishing microcapsules can achieve the following effects.

[0079] 1. The fire extinguishing film with a fire extinguishing function can be conveniently arranged in a narrow space within the battery pack, for example, the space between multiple cylindrical secondary batteries, the space between the housing and the secondary battery, etc.

[0080] 2. There is no need to change the arrangement of the cylindrical secondary batteries or the existing housing structure for arranging the fire extinguishing film. Therefore, it can also be immediately applied to off-the-shelf products.

[0081] 3. It reacts immediately at the initial stage of abnormal heating or fire occurrence of the cylindrical secondary batteries in the battery pack to reduce the heating temperature or extinguish the fire.

[0082] 4. Without the need to prepare additional space, by directly applying a relatively inexpensive fire extinguishing film to the battery pack, the problems of heat generation and fire can be solved. Therefore, a battery pack that is economical, stable, and can be miniaturized and lightweight can be manufactured.

Claims

1. A battery pack having a fire extinguishing film containing microcapsules for fire extinguishing, characterized in that, Comprising: A cylindrical secondary battery (10), with a positive electrode (11) protruding from one side surface and a negative electrode (12) formed flat on the other side surface; A housing (20) for accommodating a plurality of said cylindrical secondary batteries (10) in the transverse and longitudinal directions and forming a prescribed space; And A fire extinguishing film (30), containing fire extinguishing microcapsules, and disposed in a prescribed space within the housing (20) in the form of a flexible film, Said fire extinguishing film (30) is formed by fire extinguishing microcapsules and a polymer composition, Said fire extinguishing microcapsules are composed of a core which is a fire extinguishing agent in a liquid phase at normal temperature and which changes to a gas phase at a temperature of 30 to 300 °C, and a shell which contains a polymer resin, a precipitant and a coagulant and surrounds the core with a thickness of 50 to 2000 nm, Said polymer composition is used to disperse said fire extinguishing microcapsules and can be formed into a film form, Said shell softens at 100 to 300 °C and expands and ruptures together with the phase change of said fire extinguishing agent, thereby spraying said fire extinguishing agent outwards, Said polymer composition contains a heat-insulating material component in powder form, One surface of said fire extinguishing film (30) is attached with a double-sided adhesive or coated with an adhesive, A plurality of said fire extinguishing films (30) are disposed in a lattice shape in the space between a plurality of cylindrical secondary batteries (10) in the transverse and longitudinal directions in the form of a partition.

2. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1, characterized in that, Said fire extinguishing film (30) is in the shape of an O-ring so as to be disposed on one side surface in a manner of fitting over the positive electrode (11) of the cylindrical secondary battery (10) and disposed in the space between the positive electrode (11) and the one side surface.

3. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1, characterized in that, Said fire extinguishing film (30) is formed with a first through hole (31) for enabling the positive electrodes (11) of a plurality of cylindrical secondary batteries (10) located within the housing (20) to pass through simultaneously, and said fire extinguishing film (30) covers the space between a plurality of positive electrodes (11) and the one side surface and the space between the cylindrical secondary batteries (10).

4. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1, characterized in that, Said fire extinguishing film (30) is formed with a second through hole (32) for enabling the negative electrodes (12) of a plurality of cylindrical secondary batteries (10) located within the housing (20) to be exposed outwards simultaneously, and said fire extinguishing film (30) covers the space between the cylindrical secondary batteries (10).

5. A battery pack having a fire extinguishing film containing microcapsules for fire extinguishing, characterized in that, Comprising: A cylindrical secondary battery (10), with a positive electrode (11) protruding from one side surface and a negative electrode (12) formed flat on the other side surface; A housing (20) for accommodating a plurality of said cylindrical secondary batteries (10) in the transverse and longitudinal directions and forming a prescribed space; And A fire extinguishing film (30), containing fire extinguishing microcapsules, and disposed in a prescribed space within the housing (20) in the form of a flexible film, Said fire extinguishing film (30) is formed by fire extinguishing microcapsules and a polymer composition, Said fire extinguishing microcapsules are composed of a core which is a fire extinguishing agent in a liquid phase at normal temperature and which changes to a gas phase at a temperature of 30 to 300 °C, and a shell which contains a polymer resin, a precipitant and a coagulant and surrounds the core with a thickness of 50 to 2000 nm, Said polymer composition is used to disperse said fire extinguishing microcapsules and can be formed into a film form, While the shell softens at 100 to 300 °C, it expands and ruptures together with the phase change of the fire extinguishing agent, thereby ejecting the fire extinguishing agent outward. The polymer composition contains a heat insulating material component in powder form. One surface of the fire extinguishing film (30) is attached with double-sided tape or coated with an adhesive. The fire extinguishing film (30) is configured to respectively wind around the outer peripheral edge of the cylindrical secondary battery (10) along the longitudinal direction.

6. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1 or 5, characterized in that, The polymer composition is selected from one or more of polypropylene, (meth)acrylic acid polymers, (meth)acrylic acid monomers, 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, cellulose, bisphenol A polycarbonate, (meth)epoxy polymers, epoxy monomers, poly(ethylene-co-propylene-co-5-methylene-2-norbornene), 4,4'-isopropylidenediphenol, vinyl chloride, vinylidene chloride, tetrafluoroethylene, vinyl C1-C10 alkylates, vinyl C1-C10 alkyl ethers, vinyl pyrrolidone, vinyl carbazole, acrylic acid, acrylonitrile, acrylamide, acrylic C1-C10 alkyl esters, methacrylic acid, methacrylonitrile, methacrylamide, methacrylic C1-C10 alkyl esters, and silicone rubbers.

7. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1 or 5, characterized in that The precipitating agent contains one or more selected from potassium acetate, sodium citrate, sodium chloride, ammonium chloride, sodium iodide, potassium iodide, copper sulfate, and sodium thiocyanate.

8. The battery pack having a fire extinguishing film containing microcapsules for fire extinguishing according to claim 1 or 5, characterized in that The coagulant contains one or more selected from zinc hydroxide and iron hydroxide.

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