Battery pack

Abstract

To provide a battery pack that can sufficiently prevent the spread of fire in the event of ignition. [Solution] The battery pack 1A comprises a case 2, a plurality of batteries 3 housed in the case 2, at least one of an insulating material 4 and a heat-absorbing material placed between the plurality of batteries 3, and a fire extinguishing body 5 placed inside the case 2. Because of the insulating material 4, when one battery 3 ignites, heat is less likely to be transferred to adjacent batteries. In addition, heat is blocked even after the fire is extinguished by the action of the fire extinguishing body 5.

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] Lithium-ion batteries are used in electronic devices such as notebook computers and mobile phones, and mobile batteries because they are lightweight, have a high electromotive force, and a high energy density. In addition, lithium-ion batteries are expected to be used for in-vehicle batteries and even for large-scale energy storage modules. In recent years, lithium-ion batteries have been increasing in capacity and the number of cells used in battery packs has been increasing, so a safe battery pack is required. Patent Document 1 discloses a lithium-ion battery stack that is excellent in initial fire extinguishing when it catches fire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The lithium-ion battery stack of Patent Document 1 arranges a self-extinguishing layer between adjacent batteries in the stack to enhance the effect of initial fire extinguishing when it catches fire and prevent the spread of fire to adjacent batteries. However, in reality, preventing the spread of fire may be insufficient only by fire extinguishing by the self-extinguishing layer in some cases. Therefore, an object of the present invention is to provide a battery pack in which a plurality of batteries are housed and which can sufficiently prevent the spread of fire when it catches fire.

Means for Solving the Problems

[0005] According to the inventors' research, it has been found that when one of the multiple batteries housed in a battery pack catches fire, even if the fire is extinguished, the remaining heat can cause adjacent batteries to ignite. To prevent this type of fire spread, the present invention provides a battery pack comprising a case, multiple batteries housed in the case, at least one of an insulating material and a heat-absorbing material placed between the multiple batteries, and a fire extinguishing body placed inside the case.

[0006] In this battery pack, at least one of an insulating material and a heat-absorbing material is placed between the batteries, so that when one battery catches fire, the heat is blocked from easily transferring to adjacent batteries. Furthermore, even after the fire is extinguished by the fire extinguishing device, at least one of the insulating material and the heat-absorbing material blocks the heat, preventing the fire from unexpectedly spreading after initial extinguishing.

[0007] The insulation material may include materials with a thermal conductivity of 0.6 W / (m·K) or less. Such insulation materials have a high thermal insulation effect.

[0008] The heat-absorbing material may contain a material that exhibits an endothermic reaction at temperatures of 150°C or higher and absorbs 500 J / g or more of heat. Such a heat-absorbing material has a high heat-absorbing effect.

[0009] The fire extinguishing body has a first resin layer, a fire extinguishing layer, and a second resin layer in this order, and the fire extinguishing layer may include a base material and a fire extinguishing agent laminated on the base material. Here, the fire extinguishing agent may be solid at room temperature. In such a fire extinguishing body, the fire extinguishing agent is protected from moisture by the fire extinguishing layer being sandwiched between resin layers, so the shelf life is long. From this viewpoint, the water vapor transmission rate of the first and second resin layers at 40°C and 90% RH is 200 g / (m³). 2 It is preferable that it is less than or equal to (day).

[0010] The fire extinguishing body may have an adhesive layer on its outermost layer, and the fire extinguishing body may be attached to the inner surface of the case via this adhesive layer.

[0011] The fire extinguishing body may be in contact with at least one of the heat insulating material and the heat absorbing material. In this case, the surface in contact with at least one of the heat insulating material and the heat absorbing material may or may not have the resin layer described above.

[0012] Multiple batteries may be lithium-ion batteries. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a battery pack that houses multiple batteries and can sufficiently prevent the spread of fire in the event of ignition. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view of the battery pack according to the first embodiment. [Figure 2] Both (A) and (B) are cross-sectional views of a fire extinguishing device. [Figure 3] (A) is a cross-sectional view of the battery pack according to the second embodiment. (B) is a cross-sectional view of the battery pack according to the third embodiment. [Figure 4] (A) is a cross-sectional view of the battery pack according to the fourth embodiment. (B) is a cross-sectional view of the battery pack according to the fifth embodiment. [Modes for carrying out the invention]

[0015] The battery pack of the present invention comprises a case, a plurality of batteries housed within the case, a fire-resistant member (at least one of an insulating material and a heat-absorbing material) arranged between the plurality of batteries, and a fire extinguishing element arranged within the case. This battery pack is attached to another article to supply electricity to that article, and the orientation of the battery pack does not matter, regardless of its top, bottom, left, or right orientation. Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In each drawing, the same parts or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted.

[0016] <First Embodiment> A first embodiment of the present invention will be described. As shown in FIG. 1, the battery pack 1A of this embodiment is one in which three lithium-ion batteries 3 are hermetically housed inside a rectangular parallelepiped case 2. The three lithium-ion batteries 3 are cylindrical, and a heat insulating material 4 is wound around the side circumferential surface thereof individually. The three lithium-ion batteries 3 are fixed with wires and arranged on the same plane in the case 2 so as to face the same direction. On the surfaces of the inner surface of the case 2 other than the surface to which the lithium-ion battery 3 is fixed, plate-like fire extinguishing bodies 5 are pasted. Here, the fire extinguishing body 5 may be pasted to the inner surface of the case 2 by an adhesive layer provided on one side thereof, or may be pasted by a tape.

[0017] The case 2 may be made of resin or metal. When the case 2 is made of resin, for example, PE (polyethylene), PP (polypropylene), PVC (vinyl chloride resin), PS (polystyrene), ABS resin, AS resin, PET (polyethylene terephthalate), PMMA (acrylic resin), PC (polycarbonate), PA (polyamide), POM (acetal resin), PBT (polybutylene terephthalate), phenolic resin, epoxy resin, etc. can be mentioned. Also, from the viewpoint of heat resistance, it is preferable that one or more kinds of flame retardants are added to these resins. Examples of the flame retardant include halogen-based flame retardants, phosphorus-based flame retardants, inorganic-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, etc.

[0018] For the heat insulation material 4, in order to ensure heat insulation performance, it preferably contains a material with a thermal conductivity of 0.6 W / (m·K) or less, and more preferably contains a material with a thermal conductivity of 0.3 W / (m·K) or less. Also, preferably, the entire heat insulation material 4 has a thermal conductivity not exceeding this value. Examples of the material constituting the heat insulation material 4 include glass cloth, non-combustible paper, non-combustible board, mica sheet, glass wool, rock wool, phenolic resin, phenolic foam, etc. The heat insulation material 4 is preferably in sheet form for use by being wound around the lithium-ion battery 3, and the thickness of the sheet is preferably 0.1 mm to 10.0 mm, and more preferably 0.2 mm to 0.5 mm. In fact, for the same material, the greater the thickness, the higher the actual heat insulation effect. Therefore, the material and thickness of the heat insulation material 4 are determined in consideration of the actually required heat insulation performance.

[0019] The fire extinguishing body contains at least a fire extinguishing agent. For example, like the fire extinguishing body 5A shown in Fig. 2(A), it may be a film-like base material 7 with a fire extinguishing agent 8 supported and laminated thereon. Also, like the fire extinguishing body 5B shown in Fig. 2(B), it may be a structure where the fire extinguishing body 5A (herein referred to as the "fire extinguishing layer") is sandwiched between two resin layers 9, 9. Since the fire extinguishing agent generally has high hygroscopicity and deliquescence, it is preferably protected by the resin layers 9, 9 to have high storage stability.

[0020] The material constituting the base material 7 may be a resin or a metal. If it is a resin, examples include PET (polyethylene terephthalate), LLDPE (linear low-density polyethylene), TAC (triacetyl cellulose), PMMA (polymethacrylate), PP (polypropylene), PC (polycarbonate), ETFE (ethylene tetrafluoroethylene), PCTFE (polychlorotetrafluoroethylene), PTFE (polytetrafluoroethylene), PEN (polyethylene naphthalate). If it is a metal, aluminum can be mentioned. The thickness of the base material 7 can be, for example, 4.5 to 1000 μm, and may be 12 to 10 μm, or may be 12 to 50 μm.

[0021] The fire extinguishing agent 8 used is not particularly limited, and any agent having the so-called four elements of fire extinguishing (removal action, cooling action, suffocation action, and negative catalytic action) can be used as appropriate. Examples of fire extinguishing agents 8 include general fire extinguishing agents (such as powder-type fire extinguishing agents mainly composed of potassium salts, as well as general powder-type fire extinguishing agents such as sodium bicarbonate and phosphates), as well as sand (standard sand). When using such inorganic fire extinguishing agent materials, the fire extinguishing agent material may be dispersed in an organic solvent, and this mixture may be applied to the substrate 7 and dried to form a layer of fire extinguishing agent 8. In this embodiment, since the flame coming from the lithium-ion battery 3 is extinguished, a BC fire extinguishing agent is preferred.

[0022] The amount of extinguishing agent 8 can be appropriately selected according to the intensity of the fire at the time of ignition, the time required to extinguish the fire, the allowable space, etc. The more extinguishing agent 8 is used, the better the fire extinguishing ability and the shorter the time required to extinguish the fire. The amount of extinguishing agent 8 can be, for example, 0.4 to 3.9 g / cm³. 2 It can be set to 1.0~2.5 g / cm³ 2 That's fine.

[0023] The fire extinguishing agent 8 may be mixed with a binder (polymer resin). That is, the fire extinguishing agent 8 may be a composition containing a fire extinguishing agent (fire extinguishing agent component) and a binder. The amount of fire extinguishing agent 8 contained in the composition (fire extinguishing agent composition) can be 70 to 97% by mass based on the total amount of the fire extinguishing agent composition. When a fire extinguishing agent composition containing a fire extinguishing agent and a binder is used as the fire extinguishing agent 8, for example, a layer of fire extinguishing agent 8 may be formed by applying a coating liquid containing the fire extinguishing agent composition onto the substrate 7. Alternatively, the fire extinguishing agent 8 may be kneaded into a resin and placed on the substrate 7 to form a laminate.

[0024] The materials that make up the resin layers 9,9 can be those listed as constituent materials for the base material 7. From the viewpoint of protecting the fire extinguishing agent 8, it is preferable that the materials have high gas barrier properties, and the water vapor transmission rate at 40°C and 90%RH measured in accordance with JIS K 7129 should be 200 g / (m³). 2 It is preferable that it be less than or equal to 150g / (m²). 2It is more preferable that the thickness is less than or equal to (day). The thickness of each resin layer 9 can be, for example, 25 to 150 μm, and may be 30 to 100 μm.

[0025] The fire extinguishing body 5B may further have a water vapor barrier layer on the outer surface of the resin layers 9,9. Examples of water vapor barrier layers include polyester resin layers (e.g., PET layers) with metal oxide vapor-deposited layers such as alumina vapor-deposited layers and silica vapor-deposited layers, and metal foils such as aluminum foil. If the water vapor barrier layer has a metal oxide vapor-deposited layer, the metal oxide vapor-deposited layer may face the fire extinguishing agent 8 side. The water vapor transmission rate of the water vapor barrier layer is 10 g / (m³) as measured in accordance with JIS K 7129 at 40°C and 90% RH. 2 It may be less than or equal to 1g / (m 2 It may be less than or equal to (day). The thickness of the water vapor barrier layer can be, for example, 4.5 to 25 μm, and may be 7 to 12 μm.

[0026] In the fire extinguishing body 5B, the lamination of the fire extinguishing body (fire extinguishing layer) 5A and the resin layers 9,9 may be done, for example, by laminating them together after each layer has been manufactured separately.

[0027] The thickness of the fire extinguishing material 5 is preferably 100 μm to 1000 μm, and more preferably 300 μm to 500 μm, due to the need to attach it to the inner surface of case 2.

[0028] In the battery pack 1A of this embodiment, since the insulating material 4 is placed between the lithium-ion batteries 3, when one lithium-ion battery 3 ignites and its electrolyte burns, the heat is blocked so that it is difficult for it to be transferred to the adjacent battery. Specifically, the presence of the insulating material 4 insulates the adjacent battery so that its temperature does not rise above 200°C, thus preventing the fire from spreading to the adjacent battery. Eventually, the fire extinguishing agent 8 is released from the fire extinguishing body 5 and the flames are extinguished. Even after the fire is extinguished by the action of the fire extinguishing body 5, the insulating material 4 blocks the heat, preventing the fire from unexpectedly spreading after the initial extinguishing. In this way, initial fire extinguishing of the battery pack 1A is achieved, which prevents the fire from spreading outside the battery pack 1A, and thus minimizes the damage caused by the fire.

[0029] In this embodiment, a heat-absorbing material may be used instead of the heat-insulating material 4. Here, it is more preferable that the heat-absorbing material contains a material that exhibits an endothermic reaction at a temperature of 150°C or higher and has a heat absorption amount of 500 J / g or more. The heat-absorbing material may also exhibit an endothermic reaction at a temperature of 180°C or higher, or at a temperature of 200°C or higher. The heat absorption amount of the material constituting the heat-absorbing material may be 600 J / g or more, or 700 J / g or more. Examples of materials constituting the heat-absorbing material include aluminum hydroxide-containing paper, aluminum hydroxide, magnesium hydroxide, dawsonite, calcium hydroxide, calcium aluminate, alum, zinc borate hydrate, zinc stannate, boric acid, gypsum dihydrate, zinc nitrate, calcium carbonate, etc. If the heat-absorbing material contains, for example, aluminum hydroxide, heat can be absorbed by the latent heat of water produced by the flame.

[0030] The heat-absorbing material is preferably in sheet form for use wrapped around the lithium-ion battery 3, and the thickness of the sheet is preferably 0.1 mm to 1.0 mm, and more preferably 0.2 mm to 0.5 mm. Even with the same material, a larger thickness results in a higher practical heat absorption effect, so the material and thickness of the heat-absorbing material are determined considering the practically required heat absorption performance.

[0031] <Second Embodiment> A second embodiment of the present invention will now be described. As shown in Figure 3(A), the battery pack 1B of this embodiment differs from the battery pack 1A of the first embodiment in that the lithium-ion battery 3 is wrapped with a fire extinguishing material 5. In this embodiment, the fire extinguishing material 5 is further wrapped around the heat insulating material 4 that is wrapped around the lithium-ion battery 3. As a result, it is expected that initial fire extinguishing will be faster compared to the battery pack 1A of the first embodiment.

[0032] In the fire extinguishing body 5 wrapped around the insulation material 4, it is preferable that the layer of fire extinguishing agent 8 faces the insulation material 4. Furthermore, when using a fire extinguishing body of type 5B, which includes a resin layer 9, the resin layer 9 may not be provided on the side of the fire extinguishing agent 8 layer. Alternatively, the fire extinguishing body 5 may be formed by applying the fire extinguishing agent 8 around the insulation material 4 without including either a resin layer 9 or a base material 7.

[0033] In this embodiment as well, a heat-absorbing material may be used instead of the heat-insulating material 4. The heat-absorbing material that can be used is the same as that used in the first embodiment.

[0034] <Third Embodiment> A third embodiment of the present invention will now be described. As shown in Figure 3(B), the battery pack 1C of this embodiment has a case 2 that is divided into compartments, with three lithium-ion batteries 3 each located in a separate compartment. Specifically, two plate-shaped insulating materials 4 are arranged parallel to each other inside the case 2, dividing the case 2 into three equal parts. In each section, U-shaped plate-shaped fire extinguishing bodies 5 are arranged inside the case 2 so that their openings face the same direction in the thickness direction, and lithium-ion batteries 3 are housed inside each U-shape. As a result, one insulating material 4 and two fire extinguishing bodies 5 located on both sides of it are interposed between each lithium-ion battery 3.

[0035] In battery pack 1C, each lithium-ion battery 3 is housed in a separate compartment, making it difficult for flames from a ignition of one lithium-ion battery 3 to come into contact with other lithium-ion batteries 3. Therefore, the spread of fire to other lithium-ion batteries 3 is further prevented.

[0036] In this embodiment as well, a heat-absorbing material may be used instead of the heat-insulating material 4. The heat-absorbing material that can be used is the same as that used in the first embodiment.

[0037] <Fourth Embodiment> A fourth embodiment of the present invention will now be described. As shown in Figure 4(A), the battery pack 1D of this embodiment differs from the battery pack 1A of the first embodiment in that the insulating material 4 is not wrapped around the lithium-ion battery 3, but is instead arranged to divide the compartments as in the third embodiment. That is, two plate-shaped insulating materials 4 are placed upright and parallel to each other inside the case 2, dividing the case 2 into three equal parts, and lithium-ion batteries 3 are housed in each compartment. In other words, the insulating material 4 is placed between adjacent lithium-ion batteries 3. The insulating material 4 is fixed to the inner surface of the case 2 with tape.

[0038] In this embodiment as well, a heat-absorbing material may be used instead of the heat-insulating material 4. The heat-absorbing material that can be used is the same as that used in the first embodiment.

[0039] <Fifth Embodiment> A fifth embodiment of the present invention will now be described. As shown in Figure 4(B), the battery pack 1E of this embodiment differs from the battery pack 1D of the fourth embodiment in that two insulating materials 4, which are arranged upright and parallel to each other within the case 2, are each sandwiched between heat-absorbing materials 10 on both sides. That is, a plate-like body consisting of a three-layer structure of heat-absorbing material 10, insulating material 4, and heat-absorbing material 10 is arranged between adjacent lithium-ion batteries 3.

[0040] In this embodiment, the heat-insulating material 4 is shown sandwiched between two heat-absorbing materials 10, but conversely, the heat-absorbing material 10 may be sandwiched between two heat-insulating materials 4.

[0041] Although preferred embodiments of the present invention have been described above, the present invention is not limited in any way to the above embodiments. For example, although the battery packs 1A, 1B, and 1C described above all have a portion of the inner surface of the case 2 that does not have the fire extinguishing element 5, the present invention may also be configured to have the fire extinguishing element 5 on the entire inner surface.

[0042] Furthermore, although the above embodiment also shows a fire extinguishing body 5B in which the fire extinguishing layer (5A) is sandwiched between two resin layers 9,9, the resin layers 9,9 may be part of a sealable bag. That is, the fire extinguishing layer is enclosed in a packaging bag formed from the constituent resin of the resin layers 9,9, and the packaging bag is sealed by heat sealing or the like. In this way, a fire extinguishing body is formed with three layers: a resin layer, a fire extinguishing layer, and another resin layer, by combining the packaging bag and the fire extinguishing layer. Here, the packaging bag may have a water vapor barrier layer laminated on the outer surface of the resin layer.

[0043] Furthermore, although the fifth embodiment shows a configuration in which the heat insulating material 4 and the heat absorbing material 10 are separate components, for example, the heat insulating material, which is glass cloth, may be impregnated with the material for the heat absorbing material, and the heat insulating material and the heat absorbing material may be used as an integrated component. [Examples]

[0044] The present invention will be described in more detail below with reference to examples and comparative examples using a battery pack with the shape shown in Figure 1. However, the present invention is not limited to the following examples.

[0045] <Example 1> (Preparation of fire extinguishing devices) A powder-based fire extinguishing agent was dispersed in ethanol and coated onto a polyethylene terephthalate film (Toyobo Co., Ltd. "E7002"; 50 μm thick) as a base material. The mixture was dried in a 100°C oven for 4 minutes to obtain a fire extinguishing body with a 200 μm thick fire extinguishing agent layer.

[0046] (Battery pack construction) A 1.5mm thick stainless steel plate was processed into a U-shape to form part of a rectangular prism with internal dimensions of 80mm x 80mm x 40mm. An adhesive layer was formed on the back of the fire extinguishing body made as described above and attached to the entire inner surface of the stainless steel plate.

[0047] Three cylindrical lithium-ion batteries (ternary type, rated 3.7V, capacity 3.6Ah) were prepared and wrapped with glass cloth (Unitika "A335"; 250μm thick) as insulation. The three lithium-ion batteries were placed on a 1.5mm thick stainless steel plate to form the base of the battery pack, and the U-shaped stainless steel plate prepared above was placed over them. When placing the U-shaped stainless steel plate, it was positioned so that the top and bottom surfaces of the cylindrical lithium-ion batteries were covered, and glass plates were attached to the open sides to seal it.

[0048] (Nail-piercing test) Of the three lithium-ion batteries lined up, a nail was driven into the middle battery from the side of the U-shaped stainless steel plate. The nail penetrated the U-shaped stainless steel plate and the fire extinguishing material attached to its inner surface, and also pierced the lithium-ion battery, causing it to ignite. The flames were extinguished by the fire extinguishing material. During the fire, the fire did not spread to the adjacent batteries, and after the fire was extinguished, the fire did not spread to the adjacent batteries.

[0049] <Example 2> A fire extinguishing agent similar to that in Example 1 was applied to a release PET film to form a sheet of fire extinguishing agent, which was then attached to the inside of a U-shaped SUS plate, and the release PET film was peeled off. A battery pack was fabricated and a nail-piercing test was performed in the same manner as in Example 1. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0050] <Example 3> Except for using glass cloth as the base material, the battery pack was fabricated and a nail-piercing test was performed in the same manner as in Example 1. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0051] <Example 4> The fire extinguishing element prepared in Example 1 was sandwiched between two sheets of linear low-density polyethylene film (LLDPE film) to form the fire extinguishing element (as shown in Figure 2(B)). Except for using this fire extinguishing element, the battery pack was prepared and the nail-piercing test was performed in the same manner as in Example 1. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0052] <Example 5> A powder-based fire extinguishing agent was laminated onto aluminum foil (Toyo Aluminum Co., Ltd. "TY-X2"; 35 μm thick) as the base material. A linear low-density polyethylene film (LLDPE film) was laminated on the fire extinguishing agent side to form the fire extinguishing body. Except for the use of this fire extinguishing body, the battery pack was fabricated and a nail-piercing test was performed in the same manner as in Example 1. During ignition, the fire did not spread to adjacent batteries, and after extinguishing, the fire did not spread to adjacent batteries.

[0053] <Comparative Example 1> The battery pack was fabricated and a nail-piercing test was performed in the same manner as in Example 4, except that insulation material was not used. The fire spread to the adjacent battery during ignition and after extinguishing.

[0054] <Comparative Example 2> The battery pack was fabricated and a nail-piercing test was performed in the same manner as in Example 1, except that no fire extinguishing agent was used. The fire spread to adjacent batteries both during ignition and after extinguishing.

[0055] <Comparative Example 3> Without using fire extinguishing agents or insulation materials, a battery pack was created using only the same lithium-ion battery and SUS plate as in Example 1, and a nail-piercing test was performed. During ignition and after extinguishing, the fire spread to the adjacent battery.

[0056] Table 1 summarizes the configurations of Examples 1-5 and Comparative Examples 1-3, as well as the results of the nail-insertion test. These results show that a battery pack equipped with both a fire extinguishing element placed on the inner surface of the case and insulating material placed between batteries was able to prevent the spread of fire between adjacent batteries.

[0057] [Table 1]

[0058] <Example 6> As a heat absorbent, aluminum hydroxide-containing paper (Lintec's "Cerafoam"; 150 μm thick) was used. The nail-piercing test was performed in the same manner as in Example 1, except that a 10 mm thick bakelite plate (made of resin) was used instead of a 1.5 mm thick SUS plate to form the base of the battery pack, the heat absorbent was wrapped around the lithium-ion battery instead of the insulating material, and the fire extinguishing body was the same as that used in Example 4. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0059] <Example 7> In the same procedure as in Example 6, the nail-piercing test was performed, except that the fire extinguishing material was wrapped around the lithium-ion battery, which already had a heat-absorbing material wrapped around it, instead of being attached to the inner surface of the case. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0060] <Example 8> In the procedure of Example 6, the nail-piercing test was performed in the same manner as in Example 6, except that the heat-absorbing material was not wrapped around the lithium-ion batteries but was instead secured to the bakelite plate with tape to separate the lithium-ion batteries (as shown in Figure 4(A)). During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0061] <Example 9> The nail-piercing test was performed in the same manner as in Example 8, except that the fire extinguishing material was wrapped around the lithium-ion battery instead of being attached to the inner surface of the case. During ignition, the fire did not spread to adjacent batteries, and after extinguishing the fire, the fire did not spread to adjacent batteries.

[0062] <Example 10> The nail-piercing test was performed in the same manner as in Example 8, except that both the heat-absorbing material and the fire extinguishing material were placed to separate the lithium-ion batteries. During ignition, the fire did not spread to the adjacent battery, and after extinguishing the fire, the fire did not spread to the adjacent battery.

[0063] <Comparative Example 4> Without using fire extinguishing materials or heat-absorbing materials, a battery pack was created using the same lithium-ion battery, SUS plate, and bakelite plate as in Example 6, and a nail-piercing test was performed. During ignition and after extinguishing, the fire spread to adjacent batteries.

[0064] <Comparative Example 5> In Comparative Example 4, a battery pack was prepared in the same manner as in Example 4, except that the fire extinguishing material used in Example 4 was attached to the inner surface of the case, and a nail-piercing test was performed. The fire spread to adjacent batteries both during ignition and after extinguishing.

[0065] Table 2 summarizes the configurations of Examples 6-10 and Comparative Examples 4-5, as well as the results of the nail-insertion test. These results show that a battery pack equipped with both a heat-absorbing material placed between batteries and a fire extinguishing element placed inside the case was able to prevent the spread of fire between adjacent batteries.

[0066] [Table 2] [Industrial applicability]

[0067] This invention prevents the damage caused by battery pack ignition from escalating. [Explanation of Symbols]

[0068] 1A, 1B, 1C, 1D, 1E... Battery pack, 2... Case, 3... Lithium-ion battery, 4... Insulation material, 5 (5A, 5B)... Fire extinguishing material, 7... Base material, 8... Fire extinguishing agent, 9... Resin layer, 10... Heat absorbent material.

Claims

1. The case and Multiple batteries housed in the aforementioned case, At least one of a heat insulating material and a heat absorbing material is placed between the plurality of batteries, A battery pack comprising a fire extinguishing element placed inside the aforementioned case.

2. The battery pack according to claim 1, wherein the thermal insulation material includes a material having a thermal conductivity of 0.6 W / (m·K) or less.

3. The battery pack according to claim 1 or 2, wherein the heat-absorbing material contains a material that exhibits an endothermic reaction at a temperature of 150°C or higher and has a heat absorption amount of 500 J / g or more.

4. The fire extinguishing body has a first resin layer, a fire extinguishing layer, and a second resin layer in this order. The battery pack according to any one of claims 1 to 3, wherein the fire extinguishing layer comprises a base material and a fire extinguishing agent laminated on the base material.

5. The battery pack according to claim 4, wherein the fire extinguishing agent is solid at room temperature.

6. The water vapor permeability of the first resin layer and the second resin layer at 40°C and 90% RH is 200 g / (m²). ２ The battery pack according to claim 4 or 5, wherein the number of days is less than or equal to 2 days.

7. The fire extinguishing body has an adhesive layer on its outermost layer, The battery pack according to any one of claims 1 to 6, wherein the fire extinguishing element is attached to the inner surface of the case via the adhesive layer.

8. The battery pack according to any one of claims 1 to 7, wherein the fire extinguishing element is in contact with at least one of the heat insulating material and the heat absorbing material.

9. The battery pack according to any one of claims 1 to 8, wherein the plurality of batteries are lithium-ion batteries.

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