Battery with enhanced resistance to dendrite formation
A battery includes a case having a feedthrough port, a feedthrough assembly disposed in the feedthrough port, and a cell stack disposed within the case. The feedthrough port includes an inner conductor and an insulator core separating the inner conductor from the case. The cell stack includes an anode, a cathode, and a separator insulating the anode from the cathode, wherein the anode and cathode are offset from one another. An insulating boot surrounding the cell stack insulates the cell stack from the case. The insulating boot has an opening configured to receive therein the feedthrough assembly, which may include overmolded insulation. The interior surfaces and interior walls of the battery case may be thermal spray-coated with a dielectric material to prevent lithium dendrite formation between cathode and anode surfaces.
1. A battery, comprising:
a case;
a cell stack disposed within the case, the cell stack including
an anode having a main anode body and an anode tab projecting from the main anode body, the main anode body having an anode outer edge, the anode outer edge having a first peripheral portion distant from the anode tab, and a second peripheral portion that is a remainder of the anode outer edge, surfaces of the main anode body including an anode active material;
a cathode having a main cathode body and a cathode tab projecting from the main cathode body, the main cathode body having a cathode outer edge, the cathode outer edge having a first peripheral portion adjacent the cathode tab, and a second peripheral portion that is a remainder of the cathode outer edge, surfaces of the main cathode body including a cathode active material; and
one or more separator layers electrically insulating the anode from the cathode, the anode, the cathode and the one or more separator layers being stacked together with the main anode body offset from the main cathode body such that the first peripheral portion of the anode outer edge is recessed from the first peripheral portion of the cathode outer edge by a first offset distance, and such that the anode active material at the first peripheral portion of the anode outer edge is recessed from the cathode active material at the first peripheral portion of the cathode outer edge.
2. The battery as claimed in claim 1 , wherein the first offset distance is between about 0.010 inches and about 0.080 inches.
3. The battery as claimed in claim 1 , wherein the first offset distance is between 0.001 inches and 0.03 inches.
4. The battery as claimed in claim 1 , wherein the first offset distance is 0.015 inches.
5. The battery as claimed in claim 1 , wherein the cathode outer edge has a total length, and the first peripheral portion of the cathode outer edge has a length that is between 10% and 25% of the total length.
6. The battery as claimed in claim 1 , wherein the anode includes an anode current collector and an anode foil disposed on opposite sides of the anode current collector.
7. The battery as claimed in claim 6 , wherein the anode current collector is in the form of a solid plate or a mesh.
8. The battery as claimed in claim 1 , wherein the separator layers include a shut-down bag, and the anode is sealed in the shut-down bag.
9. The battery as claimed in claim 1 , wherein the separator layers protrude outwardly from the anode outer edge around the entirety of the main anode body.
10. The battery as claimed in claim 1 , wherein the first peripheral portion of the cathode outer edge extends between 0.15 inches and 0.75 inches from the cathode tab in a first direction along the cathode outer edge and between 0.15 inches and 0.75 inches from the cathode tab in a second direction transverse to the first direction.
11. The battery as claimed in claim 1 , wherein the second peripheral portion of the cathode outer edge is recessed from the second peripheral portion of the anode outer edge by a second offset distance.
12. The battery as claimed in claim 11 , wherein the second offset distance is the same as the first offset distance.
13. The battery as claimed in claim 1 , wherein the first peripheral portion of the cathode outer edge is the portion of the cathode outer edge that protrudes from the first peripheral portion of the anode outer edge.
14. The battery as claimed in claim 13 , wherein the second peripheral portion of the cathode outer edge is recessed from the anode outer edge.
15. The battery as claimed in claim 1 , wherein the first peripheral portion of the anode outer edge is the portion of the anode outer edge that is recessed from the cathode outer edge.
16. The battery as claimed in claim 15 , wherein the second peripheral portion of the anode outer edge is not recessed from the cathode outer edge.
17. The battery as claimed in claim 1 , wherein the anode tab is positioned between different portions of the second peripheral portion of the anode outer edge.
18. The battery as claimed in claim 1 , wherein the cathode tab is positioned between different portions of the first peripheral portion of the cathode outer edge.
19. The battery as claimed in claim 1 , wherein the second peripheral portion of the anode outer edge is aligned with the cathode outer edge.