Anisotropic Expansion of Silicon-Dominant Anodes
Systems and methods are provided for managing anisotropic expansion of silicon-dominant anodes. An example battery may include a cathode, an electrolyte, and an anode, with the anode including a current collector and an active material on a surface of the current collector. One or more characteristics of the current collector may ensure meeting particular expansion criteria. The expansion criteria may include expanding less in one of x-y directions and z-direction while expanding more in other one of the x-y directions and the z-direction, the x-y directions being parallel to the surface of the current collector and perpendicular to a thickness of the active material. The one or more characteristics include at least material of the current collector.
1 - 20 . (canceled)
21 . A battery, the battery comprising:
a cathode, an electrolyte, and an anode;
wherein the anode comprises a current collector and an active material on a surface of the current collector;
wherein one or more characteristics of the current collector ensure meeting particular expansion criteria;
wherein the expansion criteria comprise expanding less in one of x-y directions and z-direction while expanding more in other one of the x-y directions and the z-direction, the x-y directions being parallel to the surface of the current collector and perpendicular to a thickness of the active material; and
wherein the one or more characteristics comprise at least material of the current collector.
22 . The battery according to claim 21 , wherein the active material comprises a silicon content of 50% or more by weight.
23 . The battery according to claim 21 , wherein the current collector comprises a copper foil.
24 . The battery according to claim 21 , wherein the material of the current collector is configured to ensure that the anode expands less in one of the x-y directions and the z-direction while expanding more in other one of the x-y directions and the z-direction.
25 . The battery according to claim 24 , wherein an expansion of the anode during operation is configured based on use of copper-based material, and wherein the copper-based material is selected from a plurality of different types or options for the copper-based material.
26 . The battery according to claim 24 , wherein the material of the current collector comprises more rigid material, and wherein an expansion of the anode is more anisotropic when the more rigid material is used compared to a current collector comprising less rigid material.
27 . The battery according to claim 26 , wherein the more rigid material comprises nickel.
28 . The battery according to claim 26 , wherein more rigid material comprises copper coated with carbon.
29 . The battery according to claim 28 , wherein an expansion of the anode in lateral directions is less than 0.5% for the copper coated with carbon.
30 . The battery according to claim 21 , wherein the thickness of the current collector is configured to ensure that the anode expands less in one of the x-y directions and the z-direction while expanding more in other one of the x-y directions and the z-direction.
31 . The battery according to claim 30 , wherein an expansion of the anode is more anisotropic with a thicker current collector, with more anode thickness expansion and less lateral expansion compared to an anode with a thinner current collector.
32 . The battery according to claim 31 , wherein a thicker current collector is 6 μm thick or greater.
33 . The battery according to claim 32 , wherein the lateral expansion of the anode is less than 5% with a 6 μm current collector.
34 . The battery according to claim 31 , wherein a thicker current collector is 10 μm thick or greater.
35 . The battery according to claim 34 , wherein the lateral expansion of the anode is less than 2% with a 10 μm thick current collector.
36 . The battery according to claim 31 , wherein a thicker current collector is 20 μm thick or greater.
37 . The battery according to claim 36 , wherein the thickness of the current collector is configured, at least in part, based on the material of the current collector.
38 . The battery according to claim 21 , wherein the surface of the current collector comprises roughness related features to account for expansion of the anode in the x-y directions during operation of the battery, and wherein the roughness related features are based on one or more characteristics of particles in the active material.
39 . The battery according to claim 38 , wherein the roughness related features are configured based on anisotropic expansion characteristics of the anode.
40 . The battery according to claim 38 , wherein the roughness related features comprise etching features of removed material in the current collector.
41 . The battery according to claim 40 , wherein the etched features range from 1 to 50 μm across.
42 . The battery according to claim 40 , wherein the etched features range from 5 to 50 μm across.