Lithium-ion battery electrodes with shape-memory-alloy current collecting substrates
AssigneeGM Global Technology Operations LLC
InventorsMark W. Verbrugge, Xingcheng Xiao, Anil K. Sachdev
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Abstract
Lithium-ion battery electrode constructions use an array of nanowires (or of other long thin shapes) of active electrode material anchored at one end to a surface of a metal current collector sheet in an electrode assembly or construction. This form of active electrode material permits good contact with a liquid lithium-ion containing electrolyte that infiltrates the closely-spaced thin shapes. Stresses arising from volume changes in the long shapes with lithiation and de-lithiation of the active material is mitigated by strategic placement of shape memory apply forms between attachment surfaces of the active electrode material and other members of the electrode assembly.
Claims18
A lithium-ion electrochemical cell comprising a negative electrode comprising a current collector carrying a negative electrode active material;
- a positive electrode comprising a current collector carrying a positive electrode active material;
- a liquid electrolyte containing lithium ions, the liquid electrolyte contacting both electrode materials and providing transport of lithium ions between the negative electrode active material and positive electrode active material;
- and a separator preventing electrical contact between the positive and negative electrodes while providing transport of lithium ions between the electrode materials;
- the negative electrode active material and positive electrode active material being formed of different compositions with each electrode active material composition being subject to lithiation and de-lithiation during discharge and charge cycling of the electrochemical cell;
- at least one of the negative electrode and positive electrode further comprising:
- a metallic current collector sheet having opposing sheet surfaces and being formed of a metal composition that is not subject to lithiation, or volume change due to lithiation, in the cycling of the electrochemical cell;
- electrode active material formed on at least one of the current collector sheet surfaces;
- the electrode active material being formed as nanosized bodies that extend outwardly from the sheet surface a distance of at least one micrometer, with each body being in electrical contact with the current collector sheet and having a cross-sectional thickness less than five hundred nanometers, the bodies of electrode active material experiencing repeated volume changes during lithiation and de-lithiation of cell cycling;
- and
- a body of an elastic shape memory alloy formed against at least one portion of each body of the electrode active material.
A lithium-ion electrochemical cell comprising a negative electrode comprising a current collector carrying a negative electrode active material;
- a positive electrode comprising a current collector carrying a positive electrode active material;
- a liquid electrolyte containing lithium ions, the liquid electrolyte contacting both electrode active materials and providing transport of lithium ions between the negative electrode active material and positive electrode active material;
- and a separator preventing electrical contact between the positive and negative electrodes while providing transport of lithium ions between the electrode materials;
- the negative electrode active material and positive electrode active material being formed of different compositions with each electrode material composition being subject to lithiation and de-lithiation during discharge and charge cycling of the electrochemical cell;
- the negative electrode further comprising:
- a metallic current collector sheet having opposing sheet surfaces and a thickness up to about thirty micrometers, the current collector sheet being formed of a metal composition that is not subject to lithiation, or volume change due to lithiation, in the cycling of the electrochemical cell;
- negative electrode active material formed on at least one of the current collector sheet surfaces;
- the negative electrode active material being formed as nanosized bodies that extend outwardly from the sheet surface a distance of at least one micrometer with each body being in electrical contact with the current collector sheet and having a cross-sectional thickness less than five hundred nanometers, the bodies of electrode active material experiencing repeated volume changes during lithiation and de-lithiation of cell cycling;
- and
- a body of an elastic shape memory alloy formed against at least one portion of each body of the electrode active material.
Dependencies are inferred from the claim text.