Heat transfer suppression sheet and battery pack

1 . A heat transfer suppression sheet comprising:

inorganic particles comprising wet silica,

first inorganic fibers, and

second inorganic fibers,

wherein the first inorganic fibers are amorphous fibers,

the first inorganic fibers and the second inorganic fibers are randomly oriented, respectively;

and

the second inorganic fibers contain at least one kind selected from amorphous fibers having a glass transition point higher than that of the first inorganic fibers and crystalline fibers;

wherein with respect to a total mass of the heat transfer suppression sheet,

a content of the inorganic particles is 30 mass % or more and 94 mass % or less,

a content of the first inorganic fibers is 3 mass % or more and 30 mass % or less, and

a content of the second inorganic fibers is 3 mass % or more and 30 mass % or less; and

wherein an average fiber diameter of the first inorganic fibers is 1 μm or more and 20 μm or less and an average fiber diameter of the second inorganic fibers is 1 nm or more and less than 1 um.;

wherein the second inorganic fibers have a dendritic shape or a crimped shape; and

a fiber length of each of the second inorganic fibers is 0.1 mm or less.

2 . The heat transfer suppression sheet according to claim 1 ,

wherein the first inorganic fibers have a glass transition point of less than 700° C.

3 . The heat transfer suppression sheet according to claim 1 ,

wherein the first inorganic fibers are fibers containing SiO 2 , and

the second inorganic fibers are fibers containing at least one kind selected from silica fibers, alumina fibers, alumina silicate fibers, zirconia fibers, and mineral-based fibers.

4 . The heat transfer suppression sheet according to claim 3 ,

wherein the first inorganic fibers are glass fibers, and

the second inorganic fibers are the mineral-based fibers.

5 . The heat transfer suppression sheet according to claim 1 ,

wherein the inorganic particles have an average secondary particle diameter of 0.01 μm or more and 200 μm or less.

6 . The heat transfer suppression sheet according to claim 1 ,

wherein the inorganic particles contain at least one kind selected from oxide particles, carbide particles, nitride particles, and inorganic hydrate particles.

7 . The heat transfer suppression sheet according to claim 6 ,

wherein the inorganic particles contain the oxide particles.

8 . The heat transfer suppression sheet according to claim 7 ,

wherein the oxide particles have an average primary particle diameter of 0.001 μm or more and 50 μm or less.

9 . The heat transfer suppression sheet according to claim 6 ,

wherein the oxide particles contain at least one kind selected from silica, titania, zirconia, zircon, barium titanate, zinc oxide, and alumina.

10 . The heat transfer suppression sheet according to claim 6 ,

wherein the inorganic particles contain at least one kind selected from nanoparticles, hollow particles, and porous particles.

11 . The heat transfer suppression sheet according to claim 10 ,

wherein the inorganic particles contain the nanoparticles.

12 . The heat transfer suppression sheet according to claim 10 ,

wherein the nanoparticles are silica nanoparticles.

13 . The heat transfer suppression sheet according to claim 10 ,

wherein the nanoparticles have an average primary particle diameter of 1 nm or more and 100 nm or less.

14 . The heat transfer suppression sheet according to claim 9 ,

wherein the oxide particles contain titania.

15 . A battery pack comprising a plurality of battery cells connected in series or in parallel,

wherein the heat transfer suppression sheet according to claim 1 is interposed between the battery cells.