Intumescent battery pad

1. An intumescent battery pad for a lithium ion battery, comprising:

a polyurethane foam having a compression force deflection of 5 to 1,035 kilopascal at 25% deflection determined in accordance with ASTM D3574-17; and

an intumescent material comprising an acid source, a carbon source, and a blowing agent;

wherein the intumescent battery pad has a UL-V0 rating at a thickness of 1 millimeter, and

wherein the intumescent material is present as a coating layer having a thickness of 25 to 250 micrometers on at least an exterior surface of the foam.

2. The intumescent battery pad of claim 1 , wherein the intumescent battery pad has a thickness of 1 to 5 millimeters.

3. The intumescent battery pad of claim 1 , wherein the polyurethane foam has at least one of

the compression force deflection of 5 to 500 kPa at 25% deflection determined in accordance with ASTM D3574-17;

a compression force deflection of 100 to 500 kPa at 75% deflection determined in accordance with ASTM D3574-17;

a compression set at 50% deflection of 0 to 15% as determined in accordance with ASTM D3574-95, Test D at 23° C. or 70° C.; or

a SAG factor as defined by the compression force deflection at 65% divided by the compression force deflection at 25% of less than or equal to 3.

4. The intumescent battery pad of claim 1 , wherein the acid source comprises at least one of an organic or inorganic phosphorous or a sulfate;

wherein the organic or inorganic phosphorous compound comprises at least one of tris(2,3-dibromopropyl)phosphate, tris(2-chloroethyl)phosphate, tris(2,3-dichloropropyl)phosphate, tris(1-chloro-3-bromoisopropyl) phosphate, bis(1-chloro-3-bromoisopropyl)-1-chloro-3-bromoisopropyl phosphonate, polyaminotriazine phosphate, melamine phosphate, or guanylurea phosphate; an organophosphite ester; or a phosphorus-containing inorganic compound.

5. The intumescent battery pad of claim 1 , wherein the carbon source comprises at least one of dextrin, a phenol-formaldehyde resin, pentaerythritol, a clay, or a polymer.

6. The intumescent battery pad of claim 1 , wherein the blowing agent comprises at least one of a dicyandiamide, an azodicarbonamide, a melamine, a guanidine, a glycine, a urea, or a halogenated organic material.

7. The intumescent battery pad of claim 1 , wherein the blowing agent decomposes at a temperature of greater than or equal to 120° C.

8. The intumescent battery pad of claim 1 , wherein the intumescent material further comprises at least one of a synergist or a binder.

9. The intumescent battery pad of claim 1 , wherein the intumescent material is located on all of the surfaces of the intumescent battery pad.

10. The intumescent battery pad of claim 1 , wherein the polyurethane foam has

the compression force deflection of 5 to 500 kPa at 25% deflection determined in accordance with ASTM D3574-17;

a compression force deflection of 100 to 500 kPa at 75% deflection determined in accordance with ASTM D3574-17;

a compression set at 50% deflection of 0 to 15% as determined in accordance with ASTM D3574-95, Test D at 23° C. or 70° C.; and

a SAG factor as defined by the compression force deflection at 65% divided by the compression force deflection at 25% of less than or equal to 3.

11. A method of making the intumescent battery pad of claim 1 , comprising:

coating a frothed composition comprising a reactive mixture onto a release liner;

curing the reactive mixture to form the polyurethane foam; and

wherein the frothed composition comprises the intumescent material, or wherein the method further comprises depositing the intumescent material on at least one surface of the polyurethane foam to form the intumescent battery pad.

12. The method of claim 11 , wherein the coating the frothed composition comprises depositing the frothed composition on the release liner at a deposition location; and wherein the curing the reactive mixture comprises translating frothed composition and the release liner through a heating zone to cure the reactive mixture and form the polyurethane foam.

13. The method of claim 12 , wherein the depositing the intumescent material comprises translating the polyurethane foam from the heating zone to an intumescent material deposition zone and depositing the intumescent material on the polyurethane foam.

14. The method of claim 12 , wherein the depositing the intumescent material comprises translating the polyurethane foam from the heating zone to an intumescent material dipping zone to provide the intumescent material on the polyurethane foam.

15. The method of claim 12 , wherein the frothed composition comprises the intumescent material.

16. A method of making the intumescent battery pad of claim 1 , comprising depositing the intumescent material on the polyurethane foam.

17. The method of claim 16 , wherein the depositing comprises dip coating, flow coating, or spray coating.

18. A battery comprising:

at least two battery cells; and

an intumescent battery pad located in between the at least two battery cells;

wherein the intumescent battery pad comprises a polyurethane foam and an intumescent material; wherein the polyurethane foam has a compression force deflection of 5 to 1,035 kilopascal at 25% deflection determined in accordance with ASTM D3574-17; and wherein the intumescent material comprises an acid source, a carbon source, and a blowing agent;

wherein the intumescent battery pad has a UL-V0 rating at a thickness of 1 millimeter, and

wherein the intumescent material is present as a coating layer having a thickness of 25 to 250 micrometers on at least an exterior surface of the foam.

19. The battery of claim 18 , wherein the battery is a lithium ion battery for a vehicle.

20. The battery of claim 18 , wherein the polyurethane foam has

the compression force deflection of 5 to 500 kPa at 25% deflection determined in accordance with ASTM D3574-17;

a compression force deflection of 100 to 500 kPa at 75% deflection determined in accordance with ASTM D3574-17;

a compression set at 50% deflection of 0 to 15% as determined in accordance with ASTM D3574-95, Test D at 23° C. or 70° C.; and

a SAG factor as defined by the compression force deflection at 65% divided by the compression force deflection at 25% of less than or equal to 3.