Electrochemical cell separators with high crystallinity binders
AssigneePolyStor Corporation
InventorsFabrice Coustier, Gowri S. Nagarajan, Richard Mank, Richard Bradford
Life of this patent
Estimating the term…
Abstract
Provided are alternative fabrication methods and compositions for an electrochemical cell. The methods and compositions of the present invention are particularly, though not exclusively, applicable to the manufacture of polymer-cased lithium-ion secondary battery cells. Briefly, the present invention provides an electrochemical cell fabrication process wherein a PVDF-based binder specifically selected for its physical and chemical properties, in particular, its high crystallinity, is coated on a porous separator material to form a porous separator. The high crystallinity PVDF of the binder results in improved cell structure and performance.
Claims24
A method of coating an electrochemical cell electrode separator, comprising:
- contacting a porous separator material with a solution of a binder material, said binder solution comprising a polyvinylidene fluoride (PVDF) homopolymer having a crystallinity greater than about 50% by weight of the PVDF homopolymer.
A method of making an electrochemical cell, comprising:
- contacting a porous separator material with a solution of a binder material, said binder solution comprising a polyvinylidene fluoride (PVDF) homopolymer having a crystallinity greater than about 50% by weight of the PVDF homopolymer;
- evaporating solvent from said binder material solution such that a porous coating of binder is formed on the separator material;
- and
- forming an electrochemical structure having,
- a positive electrode,
- a negative electrode, and
- the porous binder-coated separator separating the two electrodes;
- packaging said electrochemical structure in a polymer casing;
- applying electrolyte to said structure in said polymer casing;
- laminating said packaged structure under heat and pressure;
- and
- sealing said polymer-cased package structure.
An electrochemical cell electrode separator, comprising:
- a porous separator material;
- and
- a porous coating of a binder formed on the separator material, said binder comprising a PVDF homopolymer having a crystallinity greater than about 50% by weight of the PVDF homopolymer.
An electrochemical cell, comprising:
- an electrochemical structure, comprising,
- a positive electrode,
- a negative electrode, and
- a porous binder-coated separator separating the two electrodes, said separator comprising,
- a porous separator material, and
- a porous coating of a PVDF homopolymer binder formed on the separator material, said binder comprising a PVDF homopolymer having a crystallinity greater than about 50% by weight of the PVDF homopolymer;
- an electrolyte;
- and
- a polymer casing.
Dependencies are inferred from the claim text.