HIGH HEAT CAPACITY MATERIALS FOR IMPROVED SAFETY OF HIGH ENERGY DENSITY BATTERIES
This disclosure describes designs for improving the safety profile of a Li-ion, Na-ion or other electrochemical device. These designs improve heat capacity and reduce or delay the triggering of thermal runaway in addition to reducing the temperature rise during thermal runaway.
1 . A battery device, comprising:
a cell, and
a high heat capacity material incorporated into the cell, wherein a total added weight of the high heat capacity material is less than 20% of a weight of the cell.
2 . The battery device of claim 1 , wherein the cell is one of a lithium ion cell, and a sodium ion cell.
3 . The battery device of claim 1 , wherein a material, with a change in specific heat capacity of at least 0.5 J/(kg·K 2 ) across any temperature range between 25° C. and 1500° C., is incorporated into the cell.
4 . The battery device of claim 1 , wherein a specific heat capacity of the high heat capacity material is greater than 1 J/(g·K) at room temperature and ambient pressure conditions.
5 . The battery device of claim 1 , wherein a specific heat capacity of the high heat capacity material is greater than 2.5 J/(g·K) at room temperature and ambient pressure conditions.
6 . The battery device of claim 1 , wherein a material, operable to undergo endothermic phase changes, is incorporated into the cell.
7 . The battery device of claim 1 , wherein a material, operable to undergo endothermic phase reactions, is incorporated into the cell.
8 . The battery device of claim 1 , wherein a material, with an endothermic enthalpy greater than 500 J/g, is incorporated into the cell.
9 . The battery device of claim 1 , wherein a material, with an endothermic enthalpy greater than 1,000 J/g, is incorporated into the cell.
10 . The battery device of claim 1 , wherein a material, with a heat absorption capacity of at least 2,000 J/g at a temperature above 25° C., is incorporated into the cell.
11 . The battery device of claim 1 , wherein a material, with a heat absorption capacity of at least 2,000 J/g at a temperature below 1,000° C., is incorporated into the cell.
12 . The battery device of claim 1 , wherein:
a beryllium compound is incorporated into the cell, and
the beryllium compound is one of BeO, BeF2, and Be(OH)2.
13 . The battery device of claim 1 , wherein:
a lithium compound is incorporated into the cell, and
the lithium compound is one of LiF, Li2O, LiOH, LiOH·H2O, Li2CO3, LiAlO2, and LiAlF4.
14 . The battery device of claim 1 , wherein:
the cell is a Li-ion cell,
one or more anodes of the cell comprise one or more of:
graphite,
silicon,
lithium,
a silicon/graphite composite, and
a silicon oxide/graphite composite,
a carbon compound is incorporated into the cell, and
the carbon compound comprises one or more of:
graphite,
amorphous hard carbon,
amorphous soft carbon,
expandable graphite,
expanded graphite,
graphene,
fullerenes,
carbon nanotubes,
carbon fibers,
carbon-carbon composites,
a carbonaceous material, and
a carbon allotrope.
15 . The battery device of claim 14 , wherein a portion of the carbon compound is inactive.
16 . The battery device of claim 1 , wherein:
the cell is a Na-ion cell, and
one or more of graphite and amorphous carbon are incorporated into the cell.
17 . The battery device of claim 1 , wherein:
the cell is a Na-ion cell,
an inactive compound is incorporated into the cell, and
the inactive compound comprises one or more of:
graphite,
amorphous hard carbon,
amorphous soft carbon,
graphene,
expanded graphite,
expandable graphite,
intercalated graphite, and
a carbonaceous material.
18 . The battery device of claim 1 , wherein:
the high heat capacity material is a nonflammable compound, and
the nonflammable compound comprises one or more of:
phosphazene,
an ionic liquid,
a phosphite/phosphate-based solvent,
trimethyl phosphate,
triethyl phosphate,
tris(2,2,2-trifluoroethyl) phosphate,
a high boiling point hydroflouroether,
1,1,2,2-tetrafluoroethyl,
2,2,3,3-tetrafluoropropyl ether,
1,1,2,2-tetrafluoroethyl,
1H,1H,5H-octafluoropentyl ether,
Novec-7300,
Novec-7500,
perfluoroether,
a perfluorocarbon solvent,
a hydrofluorocarbon solvent, and
Al2O3.
19 . The battery device of claim 1 , wherein:
the high heat capacity material is a nonflammable polymer, and
the nonflammable polymer comprises one or more of:
Teflon (PTFE),
PVDF,
PVC, and
Polyvinylidene chloride.
20 . The battery device of claim 1 , wherein:
the high heat capacity material is a polymer, and
the polymer comprises one or more of:
rubber,
paraffin wax,
hydrofluorowax,
fluorinated paraffin,
lignin,
furfural,
phenolic resin,
epoxy resin,
a cellulose-based polymer,
PET,
a polyamide,
a polyimide,
PVA,
PEEK,
PEO,
PEG,
an aramid,
polycarbonate,
polyethylene,
polyarylacetylene,
polystyrene,
PAN,
PMMA,
a polypropylene,
a silicone,
Teflon,
PVDF.
PVC,
polyvinylidene chloride,
ammonium polyphosphate (APP),
triphenyl phosphate, and
a brominated flame retardant.