Heat transfer suppression sheet, heat transfer suppression member, and battery pack

Abstract

To provide a heat transfer suppression sheet capable of maintaining a heat transfer suppression effect even when a resin substrate is burned out by high heat or flame from a battery cell in which thermal runaway has occurred, and also to provide a highly safe battery pack, capable of maintaining a heat transfer suppression effect even when a resin substrate is burned out by high heat or flame from a battery cell in which thermal runaway has occurred.SOLUTION: A heat transfer suppression sheet 1 includes a resin substrate 10, first inorganic particles 20, and second inorganic particles 30 having a melting point lower than that of the first inorganic particles 20. In addition, a heat transfer suppression member 60 has a heat insulation layer 50 on the surface of the heat transfer suppression sheet 1. Furthermore, in a battery pack 100, the heat transfer suppression sheet 1 or the heat transfer suppression member 60 is interposed between battery cells 110, and the battery cells 110 are connected in series or in parallel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heat-transfer-suppressing sheet and a heat-transfer-suppressing member for use in a battery pack, and also to a battery pack including the heat-transfer-suppressing sheet or the heat-transfer-suppressing member. [Background technology]

[0002] In recent years, from the viewpoint of environmental protection, active development of electric vehicles, hybrid vehicles, etc. that are driven by electric motors is underway. These electric vehicles, hybrid vehicles, etc. are equipped with assembled batteries in which multiple battery cells are connected in series or parallel to serve as the power source for the driving electric motor.

[0003] Lithium-ion secondary batteries, which have higher capacity and output than lead-acid batteries or nickel-metal hydride batteries, are mainly used for battery cells. If a battery cell experiences thermal runaway, where the temperature rises suddenly and continues to generate heat due to an internal short circuit or overcharging, the high heat and flames from the battery cell experiencing thermal runaway may spread to other adjacent battery cells. For this reason, heat transfer suppression sheets are placed between battery cells to prevent the transfer of thermal runaway and the spread of fire.

[0004] As an example of a heat transfer suppression sheet, Patent Document 1 describes a heat insulating material made of a urethane resin composition containing a urethane resin, a trimerization catalyst, and a flame retardant. When the fireproof material is heated by high heat or fire from a battery cell that has experienced thermal runaway, the fireproof material expands and blocks the spaces between the battery cells, preventing or delaying heat transfer to adjacent battery cells and the spread of fire. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-206604 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the heat transfer-inhibiting sheet of Patent Document 1, although it contains a flame retardant, depending on the scale and extent of the high heat and flames from a battery cell that has experienced thermal runaway, it is expected that the urethane resin, which is the base material of the insulation material, will be burned and will no longer function as an insulation material.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide a heat-transfer-suppressing sheet that can maintain its heat-transfer suppression effect even if the resin base material is burned away by high heat or flame from a battery cell that has experienced thermal runaway. Another object of the present invention is to provide a safer battery pack that can maintain its heat-transfer suppression effect even if the resin base material is burned away by high heat or flame from a battery cell that has experienced thermal runaway. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the heat-transfer-suppressing sheet having the following configuration [1].

[0009] [1] A heat-transfer-suppressing sheet comprising: a resin substrate; first inorganic particles; and second inorganic particles having a melting point lower than that of the first inorganic particles.

[0010] Preferred embodiments of the present invention relating to the heat transfer-suppressing sheet relate to the following [2] to [8].

[0011] [2] The heat-transfer-suppressing sheet according to [1], wherein the first inorganic particles and the second inorganic particles are dispersed in the resin substrate. [3] The heat-transfer-inhibiting sheet according to [1], wherein a first heat-transfer-inhibiting sheet in which the first inorganic particles are dispersed in the resin substrate and a second heat-transfer-inhibiting sheet in which the second inorganic particles are dispersed in the resin substrate are laminated together. [4] The heat-transfer-suppressing sheet according to [3], wherein the first heat-transfer-suppressing sheet and the second heat-transfer-suppressing sheet are alternately laminated in multiple layers. [5] The heat-transfer-suppressing sheet according to any one of [1] to [4], further comprising inorganic hydrate as third inorganic particles. [6] The inorganic hydrate is aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium hydroxide (Ca(OH) 2 ), zinc hydroxide (Zn(OH) 2 ), iron hydroxide (Fe(OH) 2 ), manganese hydroxide (Mn(OH) 2 ), zirconium hydroxide (Zr(OH) 2 ), gallium hydroxide (Ga(OH) 3 ) at least one selected from the group consisting of: [7] The heat-transfer-suppressing sheet according to any one of [1] to [6], wherein the second inorganic particles have a melting point of 700° C. or lower. [8] The heat-transfer-suppressing sheet according to any one of [1] to [7], further comprising a phosphate compound.

[0012] The above object of the present invention is achieved by the following configuration [9] relating to a heat transfer suppressing member.

[0013] [9] A heat-transfer-suppressing member comprising the heat-transfer-suppressing sheet according to any one of [1] to [8], and a heat-insulating layer on the surface of the heat-transfer-suppressing sheet.

[0014] The above object of the present invention is achieved by the following configuration

[10] or

[11] relating to a battery pack.

[0015]

[10] An assembled battery, comprising: a heat-transfer-suppressing sheet according to any one of [1] to [8] interposed between battery cells; and the battery cells are connected in series or in parallel.

[11] A battery pack, characterized in that the heat-transfer-suppressing member described in [9] is interposed between battery cells with the heat-transfer-suppressing sheet abutting the battery cells, and the battery cells are connected in series or in parallel. Effect of the Invention

[0016] Even if the resin substrate of the heat transfer-inhibiting sheet of the present invention is burned due to exposure to high heat and flames from a battery cell experiencing thermal runaway, the second inorganic particles, which have a low melting point, melt and penetrate between the first inorganic particles, which have excellent heat resistance, to form a three-dimensional network, thereby maintaining the excellent heat resistance of the first inorganic particles and suppressing heat transfer to adjacent battery cells and the spread of fire.

[0017] Furthermore, the heat-transfer-suppressing member of the present invention has a heat-insulating layer on the surface of the heat-transfer-suppressing sheet, and the heat-insulating performance is added to further enhance the heat-transfer-suppressing effect.

[0018] Therefore, a battery pack equipped with the heat transfer suppression sheet or heat transfer suppression member of the present invention is safer because it more effectively prevents high heat and flames from a battery cell experiencing thermal runaway from being transmitted and spreading to adjacent battery cells. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a schematic diagram of one embodiment of a heat transfer-suppressing sheet of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view that typically illustrates another embodiment of the heat-transfer-suppressing sheet of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates a schematic diagram of one embodiment of a heat-transfer suppressing member of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a battery pack (part 1) provided with the heat-transfer-suppressing sheet of the present invention shown in FIG. [Diagram 5] FIG. 5 is a schematic diagram showing a battery pack (part 2) including the heat transfer suppressing member of the present invention shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below, and can be modified and implemented as desired without departing from the gist of the present invention.

[0021] [Heat transfer suppression sheet] 1 is a cross-sectional view that typically illustrates one embodiment of the heat-transfer-suppressing sheet 1 of the present invention. As illustrated, the heat-transfer-suppressing sheet 1 has first inorganic particles 20 and second inorganic particles 30, which have a melting point lower than that of the first inorganic particles 20, dispersed in a resin substrate (also referred to as an "organic substrate") 10.

[0022] There is no restriction on the type of resin for the resin substrate 10, but since the temperature of the battery cell can rise to nearly 150°C during charging and discharging, the resin substrate 10 must have sufficient heat resistance to not melt at the temperature at which the battery cell rises. The substrate must also be able to follow the expansion and contraction that accompanies charging and discharging of the battery cell. Considering these characteristics, suitable resins include urethane resin, silicone resin, fluororesin, polyether ether ketone resin, polyamide-imide resin, polyimide resin, and polycarbonate resin.

[0023] It is also preferable for the material to have an elastic function in order to enhance adhesion to the battery cell, and for this purpose the material may further contain a foaming agent or foaming assistant.

[0024] The first inorganic particles 20 are particles made of an inorganic material having a higher melting point and higher heat resistance than the second inorganic particles 30, and are preferably, for example, oxide particles. Examples of oxide particles include silica (SiO 2 ), titania (TiO 2 ), zirconia (ZrO 2 ), zircon (ZrSiO 4 ), barium titanate (BaTiO 3 ), zinc oxide (ZnO) and alumina (Al 2 O 3) can be used. In particular, silica is a component with high heat insulating properties, and titania is a component with a high refractive index compared to other metal oxides, and is highly effective in scattering light and blocking radiant heat in a high heat range of 500°C or higher, so it is most preferable to use silica and titania as the oxide particles.

[0025] In addition, inorganic hydrate particles can be blended as third inorganic particles (not shown) in place of a portion of the first inorganic particles 20. When inorganic hydrates receive high heat from a battery cell that has experienced thermal runaway and reach a temperature above the thermal decomposition initiation temperature, they undergo thermal decomposition and release their own water of crystallization, thereby lowering the temperature of the battery cell and its surroundings, thereby exerting the so-called "endothermic effect." After releasing the water of crystallization, they instantly become an oxide, which is porous and exerts a heat insulating effect due to the countless air holes.

[0026] A specific example of an inorganic hydrate is aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium hydroxide (Ca(OH) 2 ), zinc hydroxide (Zn(OH) 2 ), iron hydroxide (Fe(OH) 2 ), manganese hydroxide (Mn(OH) 2 ), zirconium hydroxide (Zr(OH) 2 ), gallium hydroxide (Ga(OH) 3 ) etc.

[0027] For example, aluminum hydroxide contains about 35% water of crystallization, and as shown in the following formula, it decomposes thermally and releases the water of crystallization, thereby exerting an endothermic effect. After releasing the water of crystallization, it becomes a porous alumina (Al 2 O 3 ) and acts as a thermal insulator. 2Al(OH) 3 →Al 2 O 3 +3H 2 O

[0028] In a battery cell that has experienced thermal runaway, the temperature rises sharply to over 200°C, and depending on the type of battery, the temperature may continue to rise to at least around 700°C, and in some cases to around 1000°C or even higher. The thermal decomposition starting temperatures of the inorganic hydrates listed above are approximately 200°C for aluminum hydroxide, approximately 330°C for magnesium hydroxide, approximately 580°C for calcium hydroxide, approximately 200°C for zinc hydroxide, approximately 350°C for iron hydroxide, approximately 300°C for manganese hydroxide, approximately 300°C for zirconium hydroxide, and approximately 300°C for gallium hydroxide, all of which roughly overlap with the temperature range of the sudden temperature rise in a battery cell that has experienced thermal runaway, and can efficiently suppress the temperature rise, making them preferable inorganic hydrates.

[0029] The second inorganic particles 30 are particles made of an inorganic material having a lower melting point than the first inorganic particles 20. Therefore, the second inorganic particles 30 may be selected depending on the type of the first inorganic particles 20, and among them, particles called low-melting glass are preferable.

[0030] The type of low-melting glass is not particularly limited, but examples thereof include soda-lime glass, non-alkali glass, borosilicate glass, potash glass, crystal glass, titanium crystal glass, barium glass, strontium glass, alumina silicate glass, soda zinc glass, soda barium glass, vanadium glass (V 2 O 5 ) and the like. Examples of borosilicate glass include SiO 2 -B 2 O 3 -ZnO-based glass, SiO 2 -B 2 O 3 -Bi 2 O 3 Crystal glass is glass containing PbO, and SiO 2 -PbO-based glass, SiO 2 -PbO-B 2 O 3 Glasses based on SiO 2 -B 2 O 3 -PbO-based glass, etc. Barium glass is BaO-SiO2 From an environmental perspective, lead-free glass is preferred.

[0031] The heat-transfer-suppressing sheet 1 preferably further contains a flame retardant in addition to containing the resin substrate 10, the first inorganic particles 20, and the second inorganic particles 30. The inclusion of a flame retardant enhances the flame retardancy of the heat-transfer-suppressing sheet 1. There are no particular limitations on the flame retardant, and halogen-based flame retardants, phosphorus-based flame retardants, antimony-based flame retardants, etc. may be appropriately selected for use, with phosphorus-based flame retardants being preferred, and phosphate compounds being particularly preferred.

[0032] Heat-transfer-suppressing sheet 1 contains the above-mentioned components and is inserted between battery cells in a battery pack. If a battery cell experiences thermal runaway, the resulting high heat and flames may be transferred to heat-transfer-suppressing sheet 1, causing resin base material 10 to burn. However, even if the resin substrate 10 is burned, the molten second inorganic particles 30, which have a lower melting point, flow into between the first inorganic particles 20, which have higher heat resistance, and function as a binder (binding material) that bonds the first inorganic particles 20 together, thereby forming a three-dimensional network of the first inorganic particles 20.

[0033] Moreover, since it is preferable that the time required to construct a network by the first inorganic particles 20 is as short as possible, the melting point of the second inorganic particles 30 (note: the softening point in the case of glass particles) is preferably low, and is preferably 700° C. or lower, more preferably 500° C. or lower, and even more preferably 400° C. or lower. However, if the melting point of the second inorganic particles 30 is too low, in addition to causing problems such as softening during normal use of the battery cell, the viscosity when melted becomes too low, making it difficult to construct and maintain a network by the first inorganic particles 20, so that the melting point is preferably 200° C. or higher.

[0034] The network of the first inorganic particles 20 prevents heat transfer and the spread of fire to adjacent battery cells.

[0035] In order to more effectively construct a network of the first inorganic particles 20, the amount of the first inorganic particles 20 blended in the heat-transfer-suppressing sheet 1 is preferably 70 to 95 volume %, and more preferably 80 to 90 volume %, of the total amount of the blended first inorganic particles 20 and second inorganic particles 30. When third inorganic particles (inorganic hydrates) are further blended, the blending amount is an amount that replaces a portion of the first inorganic particles 20. Although there is no particular restriction on the average particle size of the first inorganic particles 20, the larger the particle size is, the fewer the number of particles is and the longer the particle intervals are, even with the same mass, making it difficult to construct a network by the first inorganic particles 20. The average particle size of the first inorganic particles 20 is preferably 10 to 1000 nm, and more preferably 10 to 100 nm. In addition, when third inorganic particles (inorganic hydrates) are blended, it is also preferable that the particle size is approximately the same as that of the first inorganic particles 20.

[0036] To facilitate the construction of a network of the first inorganic particles 20, the amount of the second inorganic particles 30 blended in the heat-transfer-suppressing sheet 1 is preferably 5 to 30 volume %, and more preferably 10 to 20 volume %, of the total amount of the first inorganic particles 20 and the second inorganic particles 30 blended. The average particle size of the second inorganic particles 30 is not particularly limited, but the larger the number of the second inorganic particles 30, the easier it is for the melted second inorganic particles 30 to flow between the first inorganic particles 20, so it is preferable that the second inorganic particles 30 have a small diameter. Even with the same mass, the smaller the particle size, the greater the number of particles, and the smaller particles take less time to melt as a whole than the larger particles, so they function suitably as a binder. The average particle size of the second inorganic particles 30 is preferably 10 to 1000 nm, more preferably 10 to 100 nm.

[0037] The heat-transfer-suppressing sheet 1 can be obtained by adding the first inorganic particles 20 and the second inorganic particles 30, and, if necessary, a foaming agent, a foaming assistant, a flame retardant, and the like to a resin that becomes the resin substrate 10, and kneading the mixture. However, if there is a large difference in specific gravity between the first inorganic particles 20 and the second inorganic particles 30, the first inorganic particles 20 and the second inorganic particles 30 may be unevenly distributed in the resin substrate 10. Thus, as shown in FIG. 2, a first heat-transfer-suppressing sheet 41 in which the first inorganic particles 20 are dispersed in the resin substrate 10 and a second heat-transfer-suppressing sheet 42 in which the second inorganic particles 30 are dispersed in the resin substrate 10 may be laminated to form a single heat-transfer-suppressing sheet 1A.

[0038] In such a heat-transfer-inhibiting sheet 1A, the resin base material 10 of the first heat-transfer-inhibiting sheet 41 and the resin base material 10 of the second heat-transfer-inhibiting sheet 42 are burned away at approximately the same time. Furthermore, since there is no uneven distribution of the first inorganic particles 20 and the second inorganic particles 30, the molten second inorganic particles 30 of the second heat-transfer-inhibiting sheet 42 are more likely to flow more uniformly between the first inorganic particles 20 of the first heat-transfer-inhibiting sheet 41. Therefore, since the resin base material 10 of the first heat-transfer-inhibiting sheet 41 and the resin base material 10 of the second heat-transfer-inhibiting sheet 42 are burned away in the same way, it is preferable that the resins used are the same.

[0039] In addition, while the heat-transfer-inhibiting sheet 1A in FIG. 2 has a two-layer structure of a first heat-transfer-inhibiting sheet 41 and a second heat-transfer-inhibiting sheet 42, it may have a multi-layer structure in which the first heat-transfer-inhibiting sheet 41 and the second heat-transfer-inhibiting sheet 42 are alternately laminated (not shown).

[0040] In the above manufacturing method, the first inorganic particles 20 can be partially replaced with third inorganic particles (inorganic hydrate).

[0041] [Heat transfer suppression material] A heat-transfer-inhibiting layer can be attached (or laminated) to the surface of the heat-transfer-inhibiting sheet 1 or heat-transfer-inhibiting sheet 1A described above to form a heat-transfer-inhibiting member. Fig. 3 shows one example of this, and shows a heat-transfer-inhibiting member 60 in which a heat-transfer-inhibiting layer 50 is attached to one surface of the heat-transfer-inhibiting sheet 1 shown in Fig. 1. Although not shown in the figure, the heat-transfer-inhibiting layer 50 can also be attached to the heat-transfer-inhibiting sheet 1A shown in Fig. 2.

[0042] The heat transfer suppression member 60 combines the heat transfer suppression effect of the heat transfer suppression sheet 1 (1A) with the insulating effect of the insulating layer 50, and the higher the insulating performance of the insulating layer 50, the more preferable. For example, the following insulating materials can be mentioned.

[0043] The heat insulating material may include inorganic particles and organic fibers. The heat insulating material has a plurality of three-dimensionally connected pores between the inorganic particles and the organic fibers. The organic fibers have a welded portion covering at least a portion of the surface, and at least a portion of the inorganic particles are welded to the surface of the organic fibers by the welded portion. As a result, the surface of the organic fibers is covered with the inorganic particles.

[0044] In the insulating material configured in this manner, since it has a plurality of three-dimensionally connected pores, it is possible to obtain the effect of air insulation and improve the insulating performance. In addition, since the insulating material contains highly flexible organic fibers, it is possible to increase the flexibility of the insulating material, and the organic fibers are easily entangled with each other, improving the strength of the insulating material as a whole. Furthermore, since the presence of pores improves the cushioning properties of the insulating material as a whole, when the battery cells expand during charging and discharging, the insulating material can absorb the expansion of the battery cells. Therefore, it is possible to suppress the destruction of the insulating layer 50 having such insulating material.

[0045] It is also preferable that at least some of the pores communicate with the surface of the insulating material and open outward. With the pores configured in this way, even if high heat from a battery cell that has experienced thermal runaway is transferred to the insulating layer 50 through the heat-transfer-suppressing sheet 1 (1A) and organic fibers or the like are decomposed, the decomposition gas does not remain inside the insulating material but is released to the outside through the pores. Therefore, from this point of view as well, the effect of preventing destruction of the insulating layer 50 can be obtained.

[0046] As described above, when the welded portion on the outer peripheral surface of the organic fiber fixes the inorganic particles to the organic fibers, it is possible to obtain the effect of suppressing the falling off (powdering) of the inorganic particles. Therefore, even if the battery cell expands and compressive stress or impact is applied to the insulating material, the effect of maintaining the shape of the insulating material can be further improved, and a decrease in the insulating effect due to compressive deformation of the insulating layer 50 can be prevented.

[0047] The insulating material preferably contains inorganic fibers. Since inorganic fibers are not easily decomposed even at high temperatures, even if the battery cell experiences thermal runaway (for example, heating to 800°C or higher) and the organic fibers of the insulating material decompose, the inorganic fibers remain, so the shape of the insulating material can be reliably maintained. Furthermore, flexible organic fibers tend to be entangled with relatively hard inorganic fibers, and the inorganic fibers and organic fibers form a three-dimensional skeleton (aggregate), which is a three-dimensional structure having spaces, and the strength of the insulating material can be further improved.

[0048] The heat insulating material may be produced by either a wet method or a dry method.

[0049] Furthermore, a mica sheet may be laminated on at least one of the first and second surfaces perpendicular to the thickness direction of the insulating material. Mica has excellent heat resistance and insulation properties, and a mica sheet made by processing a material containing mica into a sheet also has excellent impact resistance. Therefore, if the battery cell explodes and debris is generated, the insulating layer 50 can be protected by the mica sheet and prevented from being damaged.

[0050] "Battery pack (part 1)] 4 is a schematic diagram showing a battery pack 100 including the heat-transfer-restricting sheet 1 shown in FIG. 1. As shown in the figure, the battery pack 100 has the heat-transfer-restricting sheet 1 interposed between the battery cells 110. The battery cells 110 are connected in series or in parallel by bus bars. Although not shown in the figure, the battery cells 110 may be placed on a cooling plate (not shown). The heat-transfer-restricting sheet 1 and the battery cells 110, and if a cooling plate is used, the cooling plate is housed in a battery case 120.

[0051] As described above, even if the resin base material 10 is burned, the heat transfer-suppressing sheet 1 can ensure safety even if a certain battery cell 110 experiences thermal runaway, because the first inorganic particles 20 form a network to suppress heat transfer.

[0052] Although not shown in the drawings, heat-transfer-restricting sheet 1A can also be used, in which case either first heat-transfer-restricting sheet 41 or second heat-transfer-restricting sheet 42 may be in contact with battery cell 110.

[0053] [Battery pack (part 2)] Fig. 5 is a schematic diagram showing a battery pack 100 including the heat-transfer-reducing member 60 shown in Fig. 3. As shown in the figure, the heat-transfer-reducing member 60 is interposed between the battery cells 110, but the heat-transfer-reducing member 60 also has a heat-transfer-reducing sheet 1 on the other side of the heat-insulating layer 50, i.e., the heat-transfer-reducing sheet 1 is provided on both sides of the heat-insulating layer 50, and the battery cells 110 abut against the heat-transfer-reducing sheet 1.

[0054] The battery cells 40 are connected in series or in parallel by bus bars, and the heat transfer suppressing members 60 and the battery cells 110 , as well as a cooling plate, if one is used, are housed in the battery case 120 .

[0055] The heat-transfer-suppressing member 60 adds the heat-insulating effect of the heat-insulating layer 50 to the heat-transfer-suppressing effect of the heat-transfer-suppressing sheet 1, thereby further improving the safety of the battery pack 100. [Explanation of symbols]

[0056] 1. 1A Heat transfer suppression sheet 10 Resin base material (organic base material) 20. First inorganic particles 30 Secondary inorganic particles 41 First heat transfer suppression sheet 42 Second heat transfer suppression sheet 50 Insulation Layer 60 Heat transfer suppression material 100 battery packs 110 Battery Cell 120 Battery case

Claims

1. A heat transfer-suppressing sheet comprising: a resin substrate; first inorganic particles; and second inorganic particles having a melting point lower than that of the first inorganic particles.

2. The heat transfer-suppressing sheet according to claim 1 , wherein the first inorganic particles and the second inorganic particles are dispersed in the resin substrate.

3. 2. The heat-transfer-inhibiting sheet according to claim 1, wherein a first heat-transfer-inhibiting sheet in which the first inorganic particles are dispersed in the resin base material and a second heat-transfer-inhibiting sheet in which the second inorganic particles are dispersed in the resin base material are laminated together.

4. 4. The heat-transfer-suppressing sheet according to claim 3, wherein the first heat-transfer-suppressing sheet and the second heat-transfer-suppressing sheet are alternately laminated in multiple layers.

5. The heat transfer-suppressing sheet according to any one of claims 1 to 4, further comprising an inorganic hydrate as third inorganic particles.

6. The inorganic hydrate is aluminum hydroxide (Al(OH) ３ ), magnesium hydroxide (Mg(OH) ２ ), calcium hydroxide (Ca(OH) ２ ), zinc hydroxide (Zn(OH) ２ ), iron hydroxide (Fe(OH) ２ ), manganese hydroxide (Mn(OH) ２ ), zirconium hydroxide (Zr(OH) ２ ), gallium hydroxide (Ga(OH) ３ 6. The heat transfer-suppressing sheet according to claim 5, wherein the heat transfer-suppressing material is at least one selected from the group consisting of fluororesin, fluororesin, fluoroisotope, fluorosulfone, fluoroisotope and fluoroisotope.

7. 5. The heat transfer-suppressing sheet according to claim 1, wherein the melting point of the second inorganic particles is 700° C. or lower.

8. The heat transfer-suppressing sheet according to any one of claims 1 to 4, further comprising a phosphate compound.

9. A heat transfer-suppressing member comprising the heat transfer-suppressing sheet according to any one of claims 1 to 4, and a heat insulating layer on the surface of the heat transfer-suppressing sheet.

10. 5. A battery pack comprising: a heat transfer-suppressing sheet according to claim 1 interposed between battery cells; and the battery cells are connected in series or in parallel.

11. 10. A battery pack comprising: a heat-transfer-reducing member according to claim 9 interposed between battery cells with the heat-transfer-reducing sheet in contact with the battery cells; and the battery cells are connected in series or in parallel.

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