Multilayer sheet for preventing thermal runaway

1. A thermally insulating multilayer sheet comprising

a compressible layer comprising a polyurethane foam, and

a thermal insulation layer comprising an aerogel,

wherein the compressible layer has a thickness of 1 to 3 millimeters,

wherein the polyurethane foam has

a density of 5 to 65 pounds per cubic foot;

a compression force deflection of 0.2 to 125 psi, at 25% deflection determined in accordance with ASTM D3574-17; and

a compression set of 0 to 15%, determined in accordance with ASTM D 3574-95 Test D at 70° C.

2. The thermally insulating multilayer sheet of claim 1 , wherein the thermal insulation layer has a thickness of 1 to 3 millimeters.

3. The thermally insulating multilayer sheet of claim 1 , wherein the thermal insulation layer has a thermal conductivity of 0.01 to 0.09 W/m*K at 23° C., a heat of fusion of 70 to 350 J/g, or a combination thereof.

4. The thermally insulating multilayer sheet of claim 1 , further comprising a flame retardant layer, wherein the flame retardant layer comprises boehmite, aluminum hydroxide, magnesium hydroxide, an intumescent material, or a combination thereof.

5. The thermally insulating multilayer sheet of claim 1 , further comprising a flame retardant layer, wherein the flame retardant layer is disposed on a first side of the thermal insulation layer, and a second, opposite side of the thermal insulation layer is disposed on the compressible layer.

6. The thermally insulating multilayer sheet of claim 5 , further comprising an additional thermal insulation layer disposed on a side of the compressible layer opposite to the thermal insulation layer.

7. The thermally insulating multilayer sheet of claim 6 , further comprising an additional flame retardant layer disposed on the additional thermal insulation layer opposite to the compressible layer.

8. The thermally insulating multilayer sheet of claim 5 , further comprising an additional flame retardant layer disposed on a second side of the compressible layer opposite the thermal insulation layer.

9. The thermally insulating multilayer sheet of claim 1 , wherein a ratio of a thickness of the polyurethane foam to a thickness of the aerogel is in a range of 1:10 to 10:1.

10. The thermally insulating multilayer sheet of claim 1 , wherein the thermally insulating multilayer sheet has

a thickness of greater than 1 to 3 millimeters; and

a density of 6 to 30 pounds per cubic foot.

11. The thermally insulating multilayer sheet of claim 1 , wherein a density of the aerogel is 1 to 20 pounds per cubic foot.

12. The thermally insulating multilayer sheet of claim 1 , wherein a thickness of the aerogel is 1 to 3 millimeters.

13. The thermally insulating multilayer sheet of claim 1 , wherein the aerogel comprises a silica aerogel comprising reinforcing fibers.

14. The thermally insulating multilayer sheet of claim 13 , wherein the reinforcing fibers comprises polyester, oxidized polyacrylonitrile, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, fiberglass, high density polyolefin, ceramics, acrylics, fluoropolymer, polyurethane, polyamide, polyimide, or a combination thereof.

15. An electrochemical cell, comprising

the thermally insulating multilayer sheet of claim 1 disposed on at least a portion of at least one surface of the electrochemical cell.

16. The electrochemical cell of claim 15 , wherein the thermally insulating multilayer sheet is disposed on at least two surfaces of the electrochemical cell.

17. The electrochemical cell of claim 15 , wherein the electrochemical cell comprises a prismatic cell, pouch cell, or cylindrical cell.

18. An unconnected array, comprising at least two of the electrochemical cells of claim 15 .

19. A battery, comprising the electrochemical cell of claim 15 .

20. The battery of claim 19 , further comprising a battery case at least partially enclosing the electrochemical cell or the unconnected array.