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US 5,962,170 AGranted
Electrochemical cell
AssigneeValence Technology, Inc.
InventorPorter H. Mitchell
Life of this patent
Estimating the term…
Abstract
A method of preparing an electrochemical cell wherein the electrode material adheres to the current collector to create good electrical contact is provided. A critical aspect in the process of preparing the polymer mixture for both the anode and cathode slurries is that the polymer (or copolymer) not be subject to high shear so as to be degraded. Polymer degradation contributes to the creation of the polymer concentration gradient in the electrode film.
Claims26
An electrochemical cell fabricated by a process comprising the steps of:
- (a) preparing an anode film by:
- (i) mixing a first polymer in a first inert liquid solvent under low shear conditions effective not to degrade the first polymer to form a first polymer mixture;
- (ii) mixing an intercalation carbon material in a second inert liquid solvent to form a carbon mixture;
- (iii) mixing a first portion of the first polymer mixture and the carbon mixture under low shear conditions effective not to degrade the first polymer to form an anode slurry;
- and
- (iv) forming a layer of the anode slurry and allowing the first and second inert liquid solvents to evaporate to form the anode film, wherein the first polymer is homogeneously distributed within said anode film that has a first surface and an oppositely facing second surface;
- (b) preparing a cathode film by:
- (i) mixing a cathodic material in a third inert liquid solvent to form a cathodic material mixture;
- (ii) mixing a second portion of the first polymer mixture and the cathodic material mixture under low shear conditions effective not to degrade the first polymer to form a cathode slurry;
- and
- (iii) forming a layer of cathode slurry and allowing the first and third inert liquid solvents to evaporate to form a cathode film wherein the first polymer is homogeneously distributed within said cathode film that has a first surface and an oppositely facing second surface;
- (c) positioning a polymer layer between said anode film and said cathode film;
- and
- (d) placing an electrolyte solution comprising an electrolyte solvent and an inorganic salt into said anode film, cathode film and polymer layer wherein the anode film has a first polymer concentration at the first surface that is substantially equal to the first polymer concentration at the second surface and wherein the cathode film has a first polymer concentration at the first surface that is substantially equal to the first polymer concentration at the second surface.
11 more elements
An electrochemical cell fabricated by a process comprising the steps of:
- (a) preparing an anode film by:
- (i) mixing a first polymer in a first inert liquid solvent under low shear conditions effective not to degrade the first polymer to form a first polymer mixture;
- (ii) mixing an intercalation carbon material in a second inert liquid solvent to form a carbon mixture;
- (iii) mixing the first polymer mixture and the carbon mixture under low shear conditions effective not to degrade the first polymer to form an anode slurry;
- and
- (iv) forming a layer of the anode slurry and allowing the first and second inert liquid solvents to evaporate to form the anode film, wherein the first polymer is homogeneously distributed within said anode film that has a first surface and an oppositely facing second surface;
- (b) preparing a cathode film by:
- (i) mixing a second polymer in a third inert liquid solvent under low shear conditions effective not to degrade the second polymer to form a second polymer mixture;
- (ii) mixing a cathodic material in a fourth inert liquid solvent to form a cathodic material mixture;
- (iii) mixing the second polymer mixture and the cathodic material mixture under low shear conditions effective not to degrade the second polymer to form a cathode slurry;
- and
- (iv) forming a layer of cathode slurry and allowing the third and fourth inert liquid solvents to evaporate to form a cathode film wherein the second polymer is homogeneously distributed within said cathode film that has a first surface and an oppositely facing second surface;
- (c) positioning a polymer layer between said anode film and said cathode film;
- and
- (d) placing an electrolyte solution comprising an electrolyte solvent and an inorganic salt into said anode film, cathode film and polymer layer wherein the anode film has a first polymer concentration at the first surface that is substantially equal to the first polymer concentration at the second surface and wherein the cathode film has a second polymer concentration at the first surface that is substantially equal to the second polymer concentration at the second surface.
12 more elements
Dependencies are inferred from the claim text.