Thermal switch material suitable for use in controlling short circuits in lithium-ion batteries and method of making the thermal switch material
First Claim
1. A composite thermal switch material suitable for use in controlling short-circuiting in a lithium-ion battery, said composite thermal switch material comprising a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature.
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Accused Products
Abstract
A composite thermal switch material suitable for use in controlling short circuits in lithium ion batteries. The switch material comprises a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature.
18 Citations
22 Claims
- 1. A composite thermal switch material suitable for use in controlling short-circuiting in a lithium-ion battery, said composite thermal switch material comprising a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature.
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10. A laminate structure comprising:
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(a) a metal foil; and (b) a composite thermal switch material deposited on said metal foil, said composite thermal switch material comprising a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature. - View Dependent Claims (11, 12)
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13. An electrode assembly, said electrode assembly comprising:
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(a) an electrode active material; (b) an electrically conductive substrate; and (c) a composite thermal switch material positioned between said electrode active material and said electrically conductive substrate, said composite thermal switch material comprising a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature. - View Dependent Claims (14, 15)
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16. A lithium-ion battery, said lithium-ion battery comprising:
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(a) an electrolyte suitable for conducting lithium ions; (b) an anode in contact with the electrolyte, the anode containing lithium; and (c) a cathode in contact with the electrolyte, the cathode being electrically connected to the anode; (d) wherein at least one of the anode and the cathode comprises (i) an electrode active material;
(ii) an electrically conductive substrate; and
(iii) a composite thermal switch material, said composite thermal switch material being positioned between said electrode active material and said electrically conductive substrate, said composite thermal switch material comprising a substantially homogeneous matrix of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles being fused to one another and having a greater thermal expansion coefficient than the metallic nanoparticles, the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles being present in said substantially homogeneous matrix in relative proportions such that the composite thermal switch material is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature. - View Dependent Claims (17, 18, 19)
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20. A method of preparing a composite thermal switch material, said method comprising the steps of:
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(a) providing a mixture of metallic nanoparticles and non-electrically conductive polymeric nanoparticles, the non-electrically conductive polymeric nanoparticles having a greater thermal expansion coefficient than the metallic nanoparticles; (b) preparing a dispersion comprising said mixture in an organic carrier solvent; (c) spraying said dispersion onto a metal foil until a thin coating is formed thereon; (d) heating the coated metal foil to vaporize the organic carrier solvent; and (e) compressing the coated metal foil at an elevated temperature to cause the polymeric nanoparticles in the thin coating to fuse to one another, wherein the metallic nanoparticles and the non-electrically conductive polymeric nanoparticles are present in the thin coating in relative proportions such that the thin coating is electrically conductive below a switching temperature and is substantially non-electrically conductive at or above the switching temperature. - View Dependent Claims (21, 22)
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Specification